CN107709493B - Photocurable adhesive sheet, and image display device - Google Patents

Photocurable adhesive sheet, and image display device Download PDF

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Publication number
CN107709493B
CN107709493B CN201680032296.2A CN201680032296A CN107709493B CN 107709493 B CN107709493 B CN 107709493B CN 201680032296 A CN201680032296 A CN 201680032296A CN 107709493 B CN107709493 B CN 107709493B
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meth
acrylate
adhesive sheet
adhesive
sheet
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CN201680032296.2A
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CN107709493A (en
Inventor
新美嘉穗儿
山本亮太
内田贵久
稻永诚
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Mitsubishi Chemical Corp
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Mitsubishi Chemical Corp
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Priority to CN201810737369.9A priority Critical patent/CN108977113B/en
Priority to CN202010703204.7A priority patent/CN111732904A/en
Publication of CN107709493A publication Critical patent/CN107709493A/en
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/10—Adhesives in the form of films or foils without carriers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J151/00—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
    • C09J151/06—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
    • C09J4/06—Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond in combination with a macromolecular compound other than an unsaturated polymer of groups C09J159/00 - C09J187/00
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/318—Applications of adhesives in processes or use of adhesives in the form of films or foils for the production of liquid crystal displays
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/312—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier parameters being the characterizing feature
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2433/00—Presence of (meth)acrylic polymer

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Adhesive Tapes (AREA)

Abstract

Provided is an adhesive sheet which can fill in each corner by following the height difference of a bonding surface, does not reduce bonding reliability even after long-term light irradiation, and can be easily bonded. Therefore, there is proposed a pressure-sensitive adhesive sheet before photocuring, which is formed from a resin composition containing a (meth) acrylic copolymer (a), a crosslinking agent (B), and a photopolymerization initiator (C), and which has photocurability and has the following characteristics (1) and (2): (1) can maintain the shape at 0-40 ℃ and shows self-adhesion; (2) the viscosity is 100 to 3000 pas at 70 to 100 ℃.

Description

Photocurable adhesive sheet, and image display device
Technical Field
The present invention relates to a photocurable adhesive sheet before photocuring and an adhesive sheet obtained by photocuring the same. More particularly, the present invention relates to an image display device such as a computer, a mobile terminal (PDA), a game machine, a Television (TV), a car navigation system, a touch panel, a writing tablet, and the like, and an adhesive sheet suitably used as a constituent member thereof.
Background
In recent years, in order to improve visibility of an image display device, the following operations are performed: the gap between an image display panel such as a Liquid Crystal Display (LCD), a Plasma Display Panel (PDP), or an electroluminescence display (ELD) and a protective panel or a touch panel member disposed on the front surface side (viewing side) thereof is filled with an adhesive sheet, a liquid adhesive, or the like, to suppress reflection of incident light or light emitted from a display image at an air layer interface.
As a method for filling the gap between the constituent members for an image display device with such an adhesive, a method is known in which a liquid adhesive resin composition containing an ultraviolet curable resin is filled in the gap, and then irradiated with ultraviolet rays to be cured (patent document 1).
In addition, a method of filling a gap between constituent members for an image display device with an adhesive sheet is also known. For example, patent document 2 discloses: as a method for producing a laminate for image display device formation having a structure in which an image display device constituent member is laminated on at least one side of an adhesive sheet, there is a method in which an adhesive sheet once crosslinked with ultraviolet rays is bonded to an image display device constituent member, and then the adhesive sheet is irradiated with ultraviolet rays through the image display device constituent member to be secondarily cured.
Patent document 3 discloses a sheet using a hot-melt adhesive composition containing a polyurethane (meth) acrylate having a weight average molecular weight of 2 to 10 ten thousand as a main component and having a loss tangent at 25 ℃ of less than 1.
Further, patent document 4 discloses an adhesive layer suitable for bonding a touch panel, which contains a crosslinking agent and a (meth) acrylic polymer obtained by copolymerizing a monomer containing a (meth) acrylic monomer having a crosslinkable functional group and a specific macromonomer.
Documents of the prior art
Patent document
Patent document 1: international publication No. 2010/027041
Patent document 2: international publication No. 2012/032995
Patent document 3: international publication No. 2010/038366
Patent document 4: japanese patent laid-open publication No. 2013-18227
Patent document 5: japanese laid-open patent publication No. 2012-184423
Disclosure of Invention
Problems to be solved by the invention
In the field of image display devices, such as mobile phones and mobile terminals, the design has been increasingly diversified due to the reduction in thickness and high precision, and new problems have been raised accordingly. For example, a frame-shaped black shielding portion is usually printed on the peripheral edge portion of the surface protection panel. Therefore, an adhesive sheet for bonding a component member having such a printing portion is required to have a printing step following property capable of following a printing step and filling each corner.
Further, the range of use of image display devices such as touch panels is increasing, and along with this, adhesive sheets used in laminates for image display device construction are required to have adhesion reliability that does not deteriorate even when exposed to light such as illumination or sunlight for a long time.
The present invention has as its object the provision of a novel adhesive sheet which can fill each corner following the step of the adhesive surface before photocuring and which can be easily bonded because the adhesion reliability does not deteriorate even after long-term light irradiation in the state after photocuring.
The 2 nd object of the present invention is to provide a novel adhesive sheet which can obtain conformability to a stepped portion and surface flatness even when bonded to a constituent member for an image display device having a light-opaque portion such as a printed portion and a light-transmissive portion in a bonding surface, does not cause strain or deformation even in the light-opaque portion, can firmly bond adherends to each other with high cohesive force, and can prevent an exposed adhesive surface from being sticky even in an extreme environment such as a high temperature and high humidity environment.
The 3 rd object of the present invention is to provide a photo-crosslinkable pressure-sensitive adhesive sheet which has adhesiveness even before photo-crosslinking, does not cause the adhesive material to flow excessively during bonding and thus causes the adhesive resin composition to overflow or collapse, and can obtain sufficient hardness after photo-crosslinking.
Means for solving the problems
The present invention provides a pressure-sensitive adhesive sheet before photocuring, which is formed from a resin composition containing the (meth) acrylic copolymer (a), a crosslinking agent (B), and a photopolymerization initiator (C), and which has photocurability and has the following characteristics (1) and (2):
(1) can maintain the shape at 0-40 ℃ and shows self-adhesion;
(2) the viscosity is 100 to 3000 pas at 70 to 100 ℃.
The adhesive sheet proposed in the present invention to achieve the object 1 can maintain a sheet shape in a normal state at room temperature of 0 to 40 ℃, and can exhibit self-adhesiveness, so that handling is easy, and for example, positioning at the time of sticking is easy, and the sticking operation can be efficiently performed. Further, the viscosity of the adhesive becomes 100 to 3000 pas at 70 to 100 ℃ and exhibits hot-melt property, so that the adhesive can be filled following the uneven portion such as the printing step. Furthermore, the adhesive exhibits high cohesive force after photocuring, and exhibits excellent foaming resistance even after long-term light irradiation, for example, and the adhesion reliability does not decrease even after long-term light irradiation. Therefore, the photocurable adhesive sheet according to the present invention is suitably used for components of image display devices such as computers, mobile terminals (PDA), game machines, Televisions (TV), car navigation systems, touch panels, and writing pads.
The present invention has been made to achieve the object of the 2 nd aspect, and is a pressure-sensitive adhesive sheet which contains a (meth) acrylic copolymer (a) and is photocured, and which is characterized by having a sheet portion with a gel fraction of less than 1% and a sheet portion with a gel fraction of 40% or more.
The pressure-sensitive adhesive sheet proposed in the present invention to achieve the object 2 can obtain conformability to uneven portions and surface flatness and can alleviate strain and deformation in the sheet by the sheet portion having a gel fraction of less than 1%, and can firmly bond adherends to each other with high cohesive force while preventing the adhesive surface from being sticky by the sheet portion having a gel fraction of 40% or more.
Therefore, even when the adhesive sheet is bonded to a constituent member for an image display device having a light-opaque portion such as a printed portion and a light-transmissive portion in a bonding surface, for example, the adhesive sheet as a whole can have conformability to a printed step portion and surface flatness, and can be firmly bonded to each other with high cohesive force without causing strain or deformation in the light-opaque portion. Further, by making the exposed adhesive surface a hard portion, the exposed adhesive surface can be made less sticky even under extreme environments such as high temperature and high humidity.
The present invention provides an adhesive sheet for achieving the 3 rd object, which is characterized by being formed from a resin composition containing 100 parts by mass of a (meth) acrylic copolymer (A), 0.5 to 20 parts by mass of a crosslinking agent (B), and 0.1 to 5 parts by mass of a photopolymerization initiator (C), and the adhesive sheet has a tensile modulus (X) before photocrosslinking 1 ) Tensile modulus (X) after photocrosslinking 2 ) Ratio of (X) 2 /X 1 ) Is 3 or more.
The pressure-sensitive adhesive sheet of the present invention to achieve the object of the present invention as set forth in the item 3 has a tensile modulus (X) before and after photocrosslinking 1 ) The adhesive composition has a remarkably large difference in the degree of adhesion even before photocrosslinking, and the adhesive resin composition does not flow excessively during bonding and therefore does not overflow or collapse, and sufficient hardness can be obtained after photocrosslinking.
Drawings
Fig. 1 is a top perspective view showing an example of the adhesive sheet of the present invention.
Fig. 2 is a top perspective view showing another example of the adhesive sheet of the present invention.
Fig. 3 is a top perspective view showing another example of the adhesive sheet of the present invention.
Fig. 4 is a view showing an example of a psa sheet laminate including the psa sheet shown in fig. 3 (B), where (a) is a top perspective view thereof and (B) is a cross-sectional view thereof.
Fig. 5 is a top perspective view showing another example of the adhesive sheet of the present invention.
Detailed Description
An example of the embodiment of the present invention will be described in detail below. In addition, the present invention is not limited to the following embodiments.
[ adhesive sheet 1]
An adhesive sheet (referred to as "the present adhesive sheet 1") according to an embodiment of the present invention is a pre-photocuring adhesive sheet formed from a resin composition (referred to as "the present adhesive composition 1") containing a (meth) acrylic copolymer (1-a), a crosslinking agent (1-B), and a photopolymerization initiator (1-C), and has photocurability, and has the following characteristics (1) and (2):
(1) can maintain the shape at 0-40 ℃ and shows self-adhesion;
(2) the viscosity is 100 to 3000 pas at 70 to 100 ℃.
Here, the "pressure-sensitive adhesive sheet before photocuring" is not limited to a pressure-sensitive adhesive sheet that has not been subjected to a photocuring step at all, as long as it is a pressure-sensitive adhesive sheet having photocurability. That is, for example, a pressure-sensitive adhesive sheet that has undergone a photocuring step and can be further photocured is also included in the present invention as long as the effects of the present invention are achieved.
The adhesive sheet 1 has the characteristics of (1) and (2) described above in a state before photocuring, and therefore can be kept in a sheet form at room temperature of 0 to 40 ℃, in other words, in a normal state, and has self-adhesiveness, i.e., a property of exhibiting adhesive force in an original state. Further, the composition exhibits melt or fluidized hot melt properties when heated, exhibits excellent cohesive force after photocuring, and exhibits foam resistance after long-term light irradiation, for example.
< Properties in the Room temperature State >
The adhesive sheet 1 has a characteristic that (1) the sheet can be kept in a state before photocuring and in a state of room temperature of 0 to 40 ℃, and the sheet exhibits self-adhesiveness.
When the sheet-like member is held at room temperature, that is, in a normal state, handling is easy, and the productivity of the bonded member is particularly excellent. Further, when the self-adhesiveness is normally exhibited, positioning at the time of attachment, for example, is easy, and the attaching operation is very convenient.
In order to obtain such characteristics, the present adhesive sheet 1 can be produced from, for example, the adhesive composition (1-I) or (1-II) described later. Further, the present invention is not limited thereto.
(180 ℃ peeling strength at 23 ℃ 40% RH)
The adhesive sheet 1 may have the following characteristics (6). That is, (6) the 180 ° peel force to glass when the adhesive sheet 1 is peeled from the soda-lime glass at a peel angle of 180 ° and a peel speed of 60 mm/min at 23 ℃ · 40% RH may be 3N/cm or more. When the 180 ° peel force at 23 ℃ is 3N/cm or more, the adhesive has a proper adhesion to an adherend at normal temperature, and the bonding workability is excellent.
From the above viewpoint, the 180 ° peel force at 23 ℃. 40% RH of the present adhesive sheet 1 is preferably 3N/cm or more, more preferably 20N/cm or less, and particularly preferably 4N/cm or more or 15N/cm or less.
In the present adhesive sheet 1, in order to adjust the 180 ° peel force at 23 ° c.40% RH, for example, the present adhesive sheet 1 is produced from the adhesive composition (1-I) or (1-II) described later, and the kinds and composition ratio of the crosslinking agent and the photopolymerization initiator, the heating/pressurizing conditions at the time of bonding, and the light irradiation conditions after bonding may be adjusted. In addition, the method is not limited to this.
< characteristics when heated at 70 to 100 >
The adhesive sheet 1 has a characteristic (2) that the viscosity becomes 100 to 3000 pas when heated to 70 to 100 ℃ before photocuring and the adhesive sheet exhibits fluidity.
When the adhesive sheet 1 is hot-melt, the adhesive can be filled following the uneven portions such as the printing step by softening or fluidizing the adhesive by heating, and therefore, the adhesive sheet can be filled without foaming or the like.
In order to obtain such characteristics, the adhesive sheet 1 can be produced from, for example, the adhesive composition (1-I) or (1-II) described later. Further, the present invention is not limited thereto.
The viscosity of the adhesive sheet 1 is 100 to 3000 pas, preferably 150 pas or more or 2700 pas or less, preferably 200 pas or more or 2500 pas or less when heated to 70 to 100 ℃.
(180 ℃ peel force at 10% RH)
The adhesive sheet 1 may have the following characteristics (7). That is, (7) the peeling mode when the adhesive sheet 1 is peeled from the soda-lime glass at a peeling angle of 180 ° and a peeling speed of 60 mm/min at 80 ℃ · 10% RH by pressure bonding to soda-lime glass is cohesive failure, and the 180 ° peeling force to glass may be 1N/cm or less.
A180 DEG peel force at 80 ℃ of 1N/cm or less is preferred because high wettability to an adherend can be obtained.
From the above viewpoint, the 180 ° peel force at 80 ℃. 10% RH of the present adhesive sheet 1 is preferably 1N/cm or less, more preferably 0.8N/cm or less, and particularly preferably 0.5N/cm or less.
In the present adhesive sheet 1, in order to adjust the 180 ° peel force at 80 ° c.10% RH, for example, the present adhesive sheet 1 is produced from the adhesive composition (1-I) or (1-II) described later, and the kinds and composition ratio of the crosslinking agent and the photopolymerization initiator, or the heating/pressurizing conditions at the time of bonding and the light irradiation conditions after bonding may be adjusted. In addition, the method is not limited to this.
< Properties after photocuring >
The adhesive sheet 1 is photo-curable and has a characteristic that (3) after photo-curing, the viscosity at 70 to 100 ℃ is 3000 to 50000Pa & s.
The viscosity of the adhesive sheet 1 at 70 to 100 ℃ after photocuring is preferably 3000 to 50000Pa · s, more preferably 3500Pa · s or more or 48000Pa · s or less, and further preferably 4000Pa · s or more or 45000Pa · s or less, from the viewpoint of obtaining a high cohesive force.
(180 ℃ peel force at 23 ℃ 40% RH after photocuring)
The adhesive sheet 1 may have the following characteristics (4) after photocuring. That is, (4) the photo-cured adhesive sheet which is pressure-bonded to soda-lime glass and cured by light irradiation may have a 180 ° peel force from the glass at a peel angle of 180 ° and a peel speed of 60 mm/min at 23 ℃ · 40% RH of 3N/cm or more when the adhesive sheet is peeled from the soda-lime glass.
It is preferable that the 180 DEG peel force at 23 ℃ after photocuring is 3N/cm or more because the adherends can be strongly bonded to each other.
From the above viewpoint, the 180 ° peel force at 23 ℃ after photocuring of the present adhesive sheet 1 is preferably 3N/cm or more, more preferably 4N/cm or more, and particularly preferably 5N/cm or more or 30N/cm or less.
(180 ℃ peel force at 80. 10% RH after photocuring)
The adhesive sheet 1 may have the following characteristics (5) after photocuring. That is, (5) the photo-cured adhesive sheet which is pressure-bonded to soda-lime glass and cured by light irradiation may have a 180 ° peel force from the glass at a peel angle of 180 ° and a peel speed of 60 mm/min of 80 ℃ · 10% RH of 3N/cm or more when the adhesive sheet is peeled from the soda-lime glass.
A180 DEG peel force at 80 ℃ after photocuring of 3N/cm or more is preferred because the foaming resistance in a high-temperature environment is excellent.
From the above viewpoint, the 180 ° peel force at 80 ℃ after photocuring of the present adhesive sheet 1 is preferably 3N/cm or more, more preferably 4N/cm or more, and particularly preferably 5N/cm or more or 20N/cm or less.
In the present adhesive sheet 1, in order to adjust the 180 ° peel force at 23 ℃ or 80 ℃ after photocuring, for example, the present adhesive sheet 1 may be produced from the adhesive composition (1-I) or (1-II) described later, and the type and composition ratio of the crosslinking agent and the photopolymerization initiator may be adjusted, or the heating/pressurizing conditions at the time of bonding and the light irradiation conditions after bonding may be adjusted. In addition, the method is not limited to this.
< exhaust gas (outgas) Generation amount >
The present adhesive sheet 1 after photocuring preferably has an outgas generation amount of 40000ppm in terms of hexadecane or more after 24-hour light irradiation using a xenon arc lamp type light resistance tester specified in JIS K7350-2(ISO 4892-2).
When the amount of outgas generation is 40000ppm or more in terms of hexadecane, the adhesiveness of the pressure-sensitive adhesive sheet and the wettability to an adherend are improved, which is preferable.
Therefore, in the present adhesive sheet 1, the amount of outgas generated is preferably 40000ppm or more, more preferably 45000ppm or more, and particularly preferably 50000ppm or more in terms of hexadecane.
In the present psa sheet 1, the present psa sheet 1 may be produced from the psa composition (1-I) or (1-II) described below, for example, in order to keep the outgassing amount within the above-mentioned range. Further, the present invention is not limited thereto.
< reliability of foam resistance >
The present pressure-sensitive adhesive sheet 1 after photocuring preferably exhibits an anti-foaming property in a following anti-foaming test, in which the diameter of the cells is 5mm or less.
Foaming resistance test: a laminate is produced by sandwiching an adhesive sheet between two glass plates having a diagonal line length of 5 inches or more and a thickness of 1mm or less, and the diameter of bubbles generated in the adhesive sheet is measured when the laminate is irradiated with light for 24 hours by a xenon arc light resistance tester in accordance with JIS K7350-2(ISO 4892-2).
The adhesive sheet 1 has a viscosity of 3000 to 50000 pas at 70 to 100 ℃ after photocuring, and therefore can exhibit such a foaming resistance after photocuring. Therefore, the adhesive exhibits a property of not deteriorating reliability even when irradiated with light for a long time, and can obtain adhesion reliability of not deteriorating performance even when exposed to light such as illumination or sunlight for a long time when used in various image display devices.
In order to obtain such characteristics, the present adhesive sheet 1 can be produced from, for example, the adhesive composition (1-I) or (1-II) described later. Further, the present invention is not limited thereto.
< adhesive composition 1>
An example of a suitable pressure-sensitive adhesive composition 1 used for producing the pressure-sensitive adhesive sheet 1 is a pressure-sensitive adhesive composition (1-I) containing an acrylic copolymer (1-a1) composed of a graft copolymer having a macromonomer as a branch component, a crosslinking agent (1-B1), and a photopolymerization initiator (1-C1).
Another example of the present pressure-sensitive adhesive composition 1 is a pressure-sensitive adhesive composition (1-II) containing a (meth) acrylic copolymer (1-a2) in which a monomer a1 having a glass transition temperature (Tg) of less than 0 ℃, a monomer a2 having a glass transition temperature (Tg) of 0 ℃ or more and less than 80 ℃, and a monomer A3 having a glass transition temperature (Tg) of 80 ℃ or more are mixed in such a manner that a ratio of a monomer a1 having a glass transition temperature (Tg) of less than 0 ℃, a monomer a2 having a glass transition temperature (Tg) of 0 ℃ or more and less than 80 ℃, a 1: a 2: a3 is 10-40: 90-35: 0 to 25, and has a weight average molecular weight of 50000 to 400000.
In addition, the adhesive composition used to form the present adhesive sheet 1 is not limited to the adhesive composition (1-I) or (1-II).
The number average molecular weight and the weight average molecular weight are calculated by Gel Permeation Chromatography (GPC) using polystyrene as a standard substance.
When the adhesive sheet 1 is produced from the adhesive composition (1-I) or (1-II) prepared by a known method, the sheet can be maintained at room temperature and exhibits self-adhesiveness, and the sheet can be melted or fluidized by heating in an uncrosslinked state, and further can be photocured, and can exhibit excellent cohesive force after photocuring.
< adhesive composition (1-I) >
The pressure-sensitive adhesive composition (1-I) includes an acrylic copolymer (1-A1) comprising a graft copolymer having a macromonomer as a branch component, a crosslinking agent (1-B1), and a photopolymerization initiator (1-C1).
(acrylic copolymer (1-A1))
The acrylic copolymer (1-A1) as the base polymer may be a graft copolymer having a macromonomer as a branch component.
(Main component)
The main component of the acrylic copolymer (1-a1) is preferably composed of a copolymer component containing a repeating unit derived from a (meth) acrylate ester.
The glass transition temperature of the copolymer constituting the main component of the acrylic copolymer (1-A1) is preferably-70 to 0 ℃.
In this case, the glass transition temperature of the copolymer component constituting the main component means the glass transition temperature of a polymer obtained by copolymerizing only the monomer components constituting the main component of the acrylic copolymer (1-a 1). Specifically, the value is calculated by the Fox equation based on the glass transition temperature and the composition ratio of the polymer obtained from the homopolymer of each component of the copolymer.
The Fox equation is a calculated value obtained by the following formula, and can be obtained by using a value described in a polymer handbook [ polymer handbook, j.
1/(273+Tg)＝Σ(Wi/(273+Tgi))
[ in the formula, Wi represents the weight percent of the monomer i, and Tgi represents the Tg (. degree. C.) of the homopolymer of the monomer i. ]
Since the glass transition temperature of the copolymer component constituting the main component of the acrylic copolymer (1-A1) affects the flexibility of the pressure-sensitive adhesive composition (1-I) in a room temperature state and the wettability, i.e., the adhesiveness, of the pressure-sensitive adhesive composition (1-I) to an adherend, the glass transition temperature is preferably-80 ℃ to 0 ℃, particularly preferably-75 ℃ or higher or-5 ℃ or lower, and particularly preferably-70 ℃ or higher or-10 ℃ or lower, in order to obtain a proper adhesiveness (tackiness) of the pressure-sensitive adhesive composition (1-I) in a room temperature state.
Among them, even if the glass transition temperature of the copolymer component is the same temperature, the viscoelasticity can be adjusted by adjusting the molecular weight. For example, by reducing the molecular weight of the copolymer component, it can be made softer.
Examples of the (meth) acrylate monomer contained in the main component of the acrylic copolymer (1-a1) include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, isopropyl (meth) acrylate, hexyl (ethyl (meth) acrylate, hexyl (ethyl acrylate, hexyl (meth) acrylate, hexyl (ethyl (meth) acrylate, hexyl (ethyl (methyl (ethyl acrylate, hexyl (meth) acrylate, hexyl (ethyl acrylate, hexyl (meth) acrylate, hexyl (ethyl acrylate, hexyl (, Stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, isobornyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 3,5, 5-trimethylcyclohexyl acrylate, p-cumylphenol EO-modified (meth) acrylate, dicyclopentyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, benzyl (meth) acrylate, and the like. Hydroxyl-containing (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and glycerol (meth) acrylate having a hydrophilic group, an organic functional group and the like, (meth) acrylic acid, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxypropylphthalic acid, 2- (meth) acryloyloxyethylmaleic acid, 2- (meth) acryloyloxypropylmaleic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxypropylsuccinic acid, crotonic acid, fumaric acid, maleic acid, and the like, Carboxyl group-containing monomers such as itaconic acid, monomethyl maleate and monomethyl itaconate, anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, glycidyl (meth) acrylate, glycidyl α -ethacrylate, epoxy group-containing monomers such as 3, 4-epoxybutyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, amino group-containing monomers such as diethylaminoethyl (meth) acrylate, (meth) acrylamide, N-t-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide, maleic amide and maleimide, amide group-containing monomers such as vinylpyrrolidone, vinylpyridine and vinylcarbazole, heterocyclic basic monomers such as vinylpyrrolidone, vinylpyridine and vinylcarbazole, and the like, And the like.
In addition, various vinyl monomers such as styrene, t-butylstyrene, α -methylstyrene, vinyltoluene, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, alkyl vinyl ether, hydroxyalkyl vinyl ether, and alkyl vinyl monomer copolymerizable with the above acrylic monomer and methacrylic monomer can also be suitably used.
The main component of the acrylic copolymer (1-a1) preferably contains a hydrophobic (meth) acrylate monomer and a hydrophilic (meth) acrylate monomer as constituent units.
Since the main component of the acrylic copolymer (1-a1) is composed of only a hydrophobic monomer, whitening due to moist heat tends to be observed, it is preferable to introduce a hydrophilic monomer into the main component to prevent whitening due to moist heat.
Specifically, the main component of the acrylic copolymer (1-a1) includes a copolymer component obtained by randomly copolymerizing a hydrophobic (meth) acrylate monomer, a hydrophilic (meth) acrylate monomer, and a polymerizable functional group at the end of a macromonomer.
Here, the hydrophobic (meth) acrylate monomer is preferably an alkyl ester having no polar group (excluding methyl acrylate), and examples thereof include: n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, and mixtures thereof, Isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, methyl methacrylate.
Examples of the hydrophobic vinyl monomer include: vinyl acetate, styrene, t-butyl styrene, alpha-methyl styrene, vinyl toluene, alkyl vinyl monomers, and the like.
The hydrophilic (meth) acrylate monomer is preferably methyl acrylate or an ester having a polar group, and examples thereof include: hydroxyl group-containing (meth) acrylates such as methyl acrylate, meth) acrylic acid, tetrahydrofurfuryl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and glycerol (meth) acrylate, (meth) acrylic acid, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxypropylphthalic acid, 2- (meth) acryloyloxyethylmaleic acid, 2- (meth) acryloyloxypropylmaleic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxypropylsuccinic acid, crotonic acid, maleic acid, and mixtures thereof, Carboxyl group-containing monomers such as fumaric acid, maleic acid, itaconic acid, monomethyl maleate and monomethyl itaconate, anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, epoxy group-containing monomers such as glycidyl (meth) acrylate, α -glycidyl ethacrylate and 3, 4-epoxybutyl (meth) acrylate, alkoxy polyalkylene glycol (meth) acrylates such as methoxypolyethylene glycol (meth) acrylate, N-dimethylacrylamide and hydroxyethylacrylamide.
(Branch component: macromonomer)
As the graft component of the graft copolymer, the acrylic copolymer (1-A1) is preferably one in which a macromonomer is introduced and which contains a repeating unit derived from the macromonomer.
The macromonomer is a high molecular monomer having a polymerizable functional group at the end and a high molecular weight skeleton component.
The glass transition temperature (Tg) of the macromonomer is preferably higher than the glass transition temperature of the copolymer component constituting the above-mentioned acrylic copolymer (1-A1).
Specifically, the glass transition temperature (Tg) of the macromonomer affects the heating melting temperature (hot melt temperature) of the adhesive composition (1-I), and therefore the glass transition temperature (Tg) of the macromonomer is preferably 30 ℃ to 120 ℃, wherein 40 ℃ or more or 110 ℃ or less is preferred, and wherein 50 ℃ or more or 100 ℃ or less is further preferred.
When the glass transition temperature (Tg) is adjusted as described above, it is possible to maintain excellent processability and storage stability by adjusting the molecular weight, and it is possible to adjust the glass transition temperature so that hot melting occurs at around 80 ℃.
The glass transition temperature of the macromonomer itself is the glass transition temperature of the macromonomer itself, and can be measured by a Differential Scanning Calorimeter (DSC) (temperature rising rate: 5 ℃ C./minute, Tg from the inflection point of the baseline shift).
Further, it is also preferable to adjust the molecular weight and content of the macromonomer because the branched components are adsorbed to each other at room temperature, the physical crosslinking state can be maintained as the binder composition, and the physical crosslinking can be released to obtain fluidity by heating to an appropriate temperature.
From the above viewpoint, the macromonomer is preferably contained in the acrylic copolymer (1-a1) at a ratio of 5 to 30% by mass, of which 6% by mass or more or 25% by mass or less is preferable, and 8% by mass or more or 20% by mass or less is preferable.
In addition, the number average molecular weight of the macromonomer is preferably 500 or more and less than 8000, among them preferably 800 or more or less than 7500, among them preferably 1000 or more or less than 7000.
As the macromonomer, conventionally produced one (for example, macromonomer produced by Toyo Synthesis Co., Ltd.) can be suitably used.
The high molecular weight backbone component of the macromonomer is preferably an acrylic polymer or a vinyl polymer.
Examples of the high molecular weight skeleton component of the macromonomer include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, isopropyl (meth) acrylate, hexyl (ethyl (meth) acrylate, hexyl (ethyl acrylate, hexyl (meth) acrylate, hexyl (ethyl (meth) acrylate, hexyl (ethyl (methyl (ethyl acrylate, hexyl (meth) acrylate, hexyl (ethyl acrylate, hexyl (meth) acrylate, hexyl (ethyl acrylate, hexyl (, (meth) acrylate monomers such as stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, isobornyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 3,5, 5-trimethylcyclohexyl acrylate, p-cumylphenol EO-modified (meth) acrylate, dicyclopentyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, benzyl (meth) acrylate, hydroxyalkyl (meth) acrylate, meth) acrylic acid, glycidyl (meth) acrylate, (meth) acrylamide, N-dimethyl (meth) acrylamide, (meth) acrylonitrile, alkoxyalkyl (meth) acrylate, alkoxypolyalkylene glycol (meth) acrylate, and the like, Various vinyl monomers such as styrene, t-butylstyrene, α -methylstyrene, vinyltoluene, alkyl vinyl monomer, vinyl acetate, alkyl vinyl ether, and hydroxyalkyl vinyl ether, and these may be used alone or in combination of two or more.
Examples of the terminal polymerizable functional group of the macromonomer include a methacryloyl group, an acryloyl group, and a vinyl group.
(crosslinking agent (1-B1))
As the crosslinking agent (1-B1), for example, a crosslinking agent having 2 or more crosslinkable groups such as an epoxy group, an isocyanate group, an oxetanyl group, a silanol group, and a (meth) acryloyl group can be suitably selected. Among them, in terms of reactivity and strength of the obtained cured product, a polyfunctional (meth) acrylate having 2 or more (meth) acryloyl groups, preferably 3 or more (meth) acryloyl groups; (meth) acrylate having an epoxy group, an isocyanate group, or the like.
After the image display device constituting members are bonded and integrated, the sheet loses its hot-melt property by crosslinking the crosslinking agent (1-B1) in the adhesive material, and instead, exhibits a high cohesive force in a high-temperature environment, thereby obtaining excellent reliability in foaming resistance.
Examples of such (meth) acrylates include: 1, 4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerol glycidyl ether di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, bisphenol A polyalkoxy di (meth) acrylate, bisphenol F polyalkoxy di (meth) acrylate, polyalkylene glycol di (meth) acrylate, trimethylolpropane triethoxy ethyl (meth) acrylate, epsilon-caprolactone-modified tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, ethylene glycol di (meth) acrylate, ethylene glycol (meth) acrylate, and (meth), Ethoxylated pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyethylene glycol di (meth) acrylate, tris (acryloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, di (meth) acrylate of the epsilon-caprolactone adduct of hydroxypivalic acid neopentyl glycol, trimethylolpropane tri (meth) acrylate, alkoxylated trimethylolpropane tri (meth) acrylate, poly (meth) acrylate, and poly (meth) acrylate, Ultraviolet-curable polyfunctional monomers such as ditrimethylolpropane tetra (meth) acrylate; and polyfunctional acrylic oligomers such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyether (meth) acrylate, isocyanate (meth) acrylate, 1- (bis (meth) acryloyloxymethyl) ethyl isocyanate, 2- (2- (meth) acryloyloxyethyloxy) ethyl isocyanate, glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate glycidyl ether, hydroxypropyl (meth) acrylate glycidyl ether, hydroxybutyl (meth) acrylate glycidyl ether, and the like.
Among the above, polyfunctional monomers or oligomers containing a polar functional group such as a hydroxyl group are preferable from the viewpoint of improving the adhesion to an adherend and suppressing the effect of whitening by moist heat.
Among them, polyfunctional (meth) acrylates having a hydroxyl group or a carboxyl group are preferably used.
Therefore, from the viewpoint of preventing moist heat whitening, it is preferable to contain a hydrophobic acrylate monomer and a hydrophilic acrylate monomer as the main component of the acrylic copolymer (1-a1), that is, the graft copolymer, and further, it is preferable to use a polyfunctional (meth) acrylate having a hydroxyl group as the crosslinking agent (1-B).
The content of the crosslinking agent (1-B1) is not particularly limited. The amount of the acrylic copolymer (1-A1) is 0.5 to 20 parts by mass, preferably 1 part by mass or more and 15 parts by mass or less, and more preferably 2 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the acrylic copolymer.
By containing the crosslinking agent (1-B1) within the above range, the shape stability of the present adhesive sheet 1 in an uncrosslinked state and the reliability of foaming resistance in the crosslinked adhesive material can be both satisfied. In addition, the balance with other elements may be out of the range.
(photopolymerization initiator (1-C1))
The photopolymerization initiator (1-C1) functions as a reaction initiation assistant in the crosslinking reaction of the crosslinking agent (1-B1).
The photopolymerization initiator may be any of those known in the art. Among them, a photopolymerization initiator which is sensitive to ultraviolet rays having a wavelength of 380nm or less is preferable from the viewpoint of easiness of control of the crosslinking reaction.
On the other hand, light induced by the photopolymerization initiator which is sensitive to light having a wavelength longer than 380nm is preferable in that it easily reaches the depth of the adhesive sheet 1.
Photopolymerization initiators are roughly classified into two types according to the mechanism of radical generation: a cleavage type photopolymerization initiator capable of generating radicals by breaking and decomposing a single bond of the photopolymerization initiator itself; and a hydrogen abstraction type photopolymerization initiator which forms an excited complex with a hydrogen donor in the system by the photo-excited initiator and can transfer hydrogen from the hydrogen donor.
Among these, the cleavage type photopolymerization initiators decompose to form other compounds when radical is generated by irradiation with light, and once excited, lose the function as a reaction initiator. Therefore, the binder after the completion of the crosslinking reaction is preferably because the binder does not remain as an active species any longer, and the binder is not likely to cause unexpected light deterioration or the like.
On the other hand, since the hydrogen abstraction-type photopolymerization initiator does not generate a decomposition product such as a cleavage-type photopolymerization initiator when radical generation reaction is caused by irradiation with active energy rays such as ultraviolet rays, it is not likely to become a volatile component after the reaction is completed, and is useful in that damage to an adherend can be reduced.
Examples of the cleavage type photoinitiator include: 2, 2-dimethoxy-1, 2-diphenylethan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- (4- (2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- [4- {4- (2-hydroxy-2-methyl-propionyl) benzyl } phenyl ] -2-methyl-propan-1-one, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone); poly (1-hydroxy-2-methyl-1-one, poly (2-hydroxy-2-methyl-1-propanone); poly (2-hydroxy-2-1-methyl-1-methyl-propanone); poly (1-hydroxy-2-methyl-1-propanone); poly (1-methyl-propanone); poly (1-hydroxy-1-methyl-propanone), Methyl phenylglyoxylate, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropan-1-one, 2- (dimethylamino) -2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholino) phenyl ] -1-butanone, bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, derivatives of these, and the like.
Examples of the hydrogen abstraction photoinitiator include: benzophenone, 4-methyl-benzophenone, 2,4, 6-trimethylbenzophenone, 4-phenylbenzophenone, 3' -dimethyl-4-methoxybenzophenone, 4- (meth) acryloyloxybenzophenone, methyl 2-benzoylbenzoate, methyl benzoylformate, bis (2-phenyl-2-oxoacetic acid) oxydiethylene, 4- (1, 3-acryloyl-1, 4,7,10, 13-pentaoxotridecyl) benzophenone, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2, 4-dimethylthioxanthone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, derivatives thereof, and the like.
The photopolymerization initiator is not limited to the above examples. Any one of the above-listed cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators may be used, or two or more thereof may be used in combination.
The content of the photopolymerization initiator (1-C1) is not particularly limited. For reference, the amount of the acrylic copolymer (1-A1) is preferably 0.1 to 10 parts by mass, more preferably 0.5 part by mass or less, or 5 parts by mass or less, more preferably 1 part by mass or less, or 3 parts by mass or less, per 100 parts by mass of the acrylic copolymer.
By setting the content of the photopolymerization initiator (1-C1) to the above range, appropriate response sensitivity to active energy rays can be obtained.
(other Components)
The pressure-sensitive adhesive composition (1-I) may contain, as components other than those described above, known components usually blended in pressure-sensitive adhesive compositions. For example, various additives such as a tackifier resin, an antioxidant, a light stabilizer, a metal deactivator, an antioxidant, a moisture absorbent, a polymerization inhibitor, an ultraviolet absorber, a rust inhibitor, a silane coupling agent, and inorganic particles may be suitably contained as required.
Further, if necessary, a reaction catalyst (tertiary amine compound, quaternary ammonium compound, tin laurate compound, etc.) may be suitably contained.
< adhesive composition (1-II) >
The pressure-sensitive adhesive composition (1-II) includes a pressure-sensitive adhesive composition containing a (meth) acrylic copolymer (1-a2) containing a monomer a1 having a glass transition temperature (Tg) of less than 0 ℃, a monomer a2 having a glass transition temperature (Tg) of 0 ℃ or more and less than 80 ℃, and a monomer A3 having a glass transition temperature (Tg) of 80 ℃ or more, a crosslinking agent (1-B2), and a photopolymerization initiator (1-C2), and the pressure-sensitive adhesive composition (1-II) includes a pressure-sensitive adhesive composition containing a (meth) acrylic copolymer (1-a2) containing a monomer a1 having a glass transition temperature (Tg) of less than 0 ℃, a monomer a2 having a glass transition temperature (Tg) of 0 ℃ or more and less than 80 ℃, a monomer A3 having a glass transition temperature (Tg) of 80 ℃ or more, a 1: a 2: a3 is 10-40: 90-35: a (meth) acrylate copolymer or an ethylene copolymer having a weight average molecular weight of 50000 to 400000, which is obtained by copolymerization at a molar ratio of 0 to 25.
((meth) acrylic acid-based copolymer (1-A2))
The (meth) acrylic copolymer (1-a2) as the base polymer is preferably a (meth) acrylate copolymer or an ethylene copolymer.
The weight average molecular weight of the (meth) acrylate copolymer or the ethylene copolymer is preferably 50000 to 500000, more preferably 60000 or higher or 450000 or lower, and still more preferably 70000 or higher or 400000 or lower, from the viewpoint of satisfying both the shape retention property in a room temperature state and the hot-melt property.
The physical properties such as glass transition temperature (Tg) and molecular weight of the acrylate copolymer can be appropriately adjusted by appropriately selecting the kind and composition ratio of the acrylic monomer and methacrylic monomer used for the preparation thereof, and further the polymerization conditions.
In this case, examples of the acrylic monomer constituting the acrylic ester copolymer include 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, n-butyl acrylate, ethyl acrylate, and the like as a main raw material.
In addition to these, a (meth) acrylic monomer having various functional groups may be copolymerized with the above acrylic monomer for the purpose of imparting cohesive force, imparting polarity, and the like.
Examples of the (meth) acrylic monomer having such a functional group include methyl methacrylate, methyl acrylate, hydroxyethyl acrylate, acrylic acid, glycidyl acrylate, N-substituted acrylamide, acrylonitrile, methacrylonitrile, fluorine-containing alkyl acrylate, and organic silyl acrylate.
On the other hand, examples of the ethylene copolymer include ethylene copolymers obtained by further polymerizing various vinyl monomers such as vinyl acetate, alkyl vinyl ether, and hydroxyalkyl vinyl ether copolymerizable with the above acrylic monomer and methacrylic monomer.
As the (meth) acrylic copolymer (1-a2) of the present adhesive sheet 1, it is preferable to use a monomer a1 having a glass transition temperature (Tg) of less than 0 ℃, a monomer a2 having a glass transition temperature (Tg) of 0 ℃ or more and less than 80 ℃, and a monomer a3 having a glass transition temperature (Tg) of 80 ℃ or more in the ratio of a 1: a 2: a3 is 10-40: 90-35: (meth) acrylate copolymer or ethylene copolymer copolymerized in a molar ratio of 0 to 25.
In this case, the glass transition temperatures (Tg) of the monomers a1, a2, and a3 are the glass transition temperatures (Tg) when a polymer is produced from the monomers (homopolymerization).
The monomer a1 is preferably, for example, a (meth) acrylate monomer having the following alkyl structure: the alkyl structure is an alkyl structure having a side chain having 4 or more carbon atoms.
In this case, the side chain having 4 or more carbon atoms may be a straight chain or a branched carbon chain.
More specifically, the monomer a1 is preferably a (meth) acrylate monomer having a C4-10 linear alkyl structure or a (meth) acrylate monomer having a C6-18 branched alkyl structure.
Here, examples of the "(meth) acrylate monomer having a linear alkyl group structure having 4 to 10 carbon atoms" include: n-butyl acrylate, n-hexyl acrylate, n-octyl acrylate, n-nonyl acrylate, n-decyl acrylate, and the like.
On the other hand, examples of the "(meth) acrylate monomer having a branched alkyl group with 6 to 18 carbon atoms" include: 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-methylhexyl acrylate, isooctyl acrylate, isononyl acrylate, isodecyl methacrylate, and the like.
The monomer a2 is preferably a (meth) acrylate monomer having 4 or less carbon atoms, a (meth) acrylate monomer having a cyclic skeleton in a side chain thereof, a vinyl monomer having 4 or less carbon atoms, or a vinyl monomer having a cyclic skeleton in a side chain thereof.
Among these, the monomer a2 is particularly preferably a vinyl monomer having a side chain of 4 or less carbon atoms.
Here, examples of the "c 4 or less (meth) acrylate monomer" include: methyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl acrylate, isobutyl methacrylate, and the like.
Examples of the "(meth) acrylate monomer having a cyclic skeleton in a side chain" include: isobornyl acrylate, cyclohexyl methacrylate, 1, 4-cyclohexanedimethanol monoacrylate, tetrahydrofurfuryl methacrylate, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 3, 5-trimethylcyclohexanol acrylate, cyclic trimethylolpropane formal acrylate, 4-ethoxylated cumylphenol acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentenyl acrylate, and the like.
Examples of the "vinyl monomer having 4 or less carbon atoms" include: vinyl acetate, vinyl propionate, vinyl butyrate, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, and the like.
Examples of the "vinyl monomer having a cyclic skeleton in a side chain" include: styrene, cyclohexyl vinyl ether, norbornyl vinyl ether, norbornenyl vinyl ether, and the like. Among them, a vinyl monomer having a side chain of 4 or less carbon atoms or an acrylate monomer having a side chain of 4 or less carbon atoms is particularly preferable.
The monomer a3 is preferably a (meth) acrylate monomer having a side chain with 1 or less carbon atoms, or a (meth) acrylate monomer having a cyclic skeleton in the side chain.
Here, examples of the "(meth) acrylate monomer having a side chain with 1 or less carbon atoms" include: methyl methacrylate, acrylic acid, methacrylic acid, and the like.
Examples of the "(meth) acrylate monomer having a cyclic skeleton in a side chain" include: isobornyl methacrylate, 3, 5-trimethylcyclohexyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl methacrylate, dicyclopentenyl methacrylate, and the like.
The (meth) acrylic copolymer (1-a2) comprises a mixture of a monomer a1 and a monomer a2 and a monomer a3 in a ratio of a 1: a 2: a3 is 10-40: 90-35: the (meth) acrylate copolymer or ethylene copolymer copolymerized in a molar ratio of 0 to 25 can have a Tan delta peak of 0 to 20 ℃ and can maintain a sheet-like shape in a normal state, i.e., at room temperature. Further, a property of adhering to an adherend in a short time by a slight force (referred to as "tackiness") can be exhibited. When heated to a temperature at which the adhesive can be melted, the adhesive exhibits fluidity and can be filled into the corners following the step portions of the adhesive surface.
Therefore, from the viewpoint described above, the molar ratio of the monomer a1 to the monomer a2 to the monomer a3 in the (meth) acrylate ester copolymer or the ethylene copolymer constituting the (meth) acrylic copolymer (1-a2) is preferably a ratio of a 1: a 2: a3 is 10-40: 90-35: 0 to 25, preferably 13 to 40: 87-35: 0 to 23, preferably 15 to 40: 85-38: 2 to 20.
From the same viewpoints as described above, the molar ratio of the monomer a1 to the monomer a2 to the monomer a3 in the (meth) acrylate copolymer or the ethylene copolymer of the (meth) acrylic copolymer (1-a2) is preferably a2> a1> a 3.
(crosslinking agent (1-B2))
By crosslinking the crosslinking agent (1-B2) in the present adhesive sheet 1, the present adhesive sheet 1 can exhibit high cohesive force in a high-temperature environment, and excellent reliability in resistance to foaming can be obtained.
As such a crosslinking agent (1-B2), for example, a crosslinking agent having 2 or more crosslinkable groups such as an epoxy group, an isocyanate group, an oxetanyl group, a silanol group, and a (meth) acryloyl group can be suitably selected. Among them, in terms of reactivity and strength of the obtained cured product, a polyfunctional (meth) acrylate having 2 or more (meth) acryloyl groups, preferably 3 or more (meth) acryloyl groups; (meth) acrylate having an epoxy group, an isocyanate group, or the like.
Examples of such (meth) acrylates include: 1, 4-butanediol di (meth) acrylate, glycerol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, bisphenol A polypropoxy di (meth) acrylate, bisphenol F polyethoxy di (meth) acrylate, ethylene glycol di (meth) acrylate, trimethylolpropane triethoxyethyl (meth) acrylate, epsilon-caprolactone-modified tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and mixtures thereof, Propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyethylene glycol di (meth) acrylate, tris (acryloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, ultraviolet-curable polyfunctional monomers such as tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, di (meth) acrylate of an epsilon-caprolactone adduct of hydroxypivalic acid neopentyl glycol, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxy tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and the like; and polyfunctional acrylic oligomers such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyether (meth) acrylate, isocyanate (meth) acrylate, 1- (bis (meth) acryloyloxymethyl) ethyl isocyanate, 2- (2- (meth) acryloyloxyethyloxy) ethyl isocyanate, glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate glycidyl ether, hydroxypropyl (meth) acrylate glycidyl ether, hydroxybutyl (meth) acrylate glycidyl ether, and the like.
Among the above, polyfunctional monomers or oligomers having a polar functional group are preferable from the viewpoint of improving the adhesion to an adherend, heat resistance, and the effect of suppressing whitening by moist heat. Among them, polyfunctional (meth) acrylates having an isocyanuric ring skeleton are preferably used.
The content of the crosslinking agent (1-B2) is not particularly limited. The ratio is 0.5 to 20 parts by mass, preferably 1 part by mass or more and 15 parts by mass or less, and preferably 2 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the (meth) acrylic copolymer (1-a 2).
By containing the crosslinking agent (1-B2) within the above range, the shape stability of the present adhesive sheet 1 in an uncrosslinked state and the reliability of the foaming resistance in the crosslinked adhesive sheet can be both satisfied. In addition, the balance with other elements may be out of the range.
(photopolymerization initiator (1-C2))
The photopolymerization initiator (1-C2) functions as a reaction initiation assistant in the crosslinking reaction of the crosslinking agent (1-B2), and the photopolymerization initiator (1-C1) described above can be suitably used.
The content of the photopolymerization initiator (1-C2) is not particularly limited. For reference, it is preferable that the content is 0.1 to 10 parts by mass, 0.5 part by mass or more or 5 parts by mass or less, or 1 part by mass or more or 3 parts by mass or less, based on 100 parts by mass of the (meth) acrylic copolymer (1-a 2).
By setting the content of the photopolymerization initiator (1-C2) to the above range, appropriate response sensitivity to active energy rays can be obtained.
(other Components)
The pressure-sensitive adhesive composition (1-II) may contain, as components other than those described above, known components usually blended in pressure-sensitive adhesive compositions. For example, various additives such as a tackifier resin, an antioxidant, a light stabilizer, a metal deactivator, an antioxidant, a moisture absorbent, a polymerization inhibitor, an ultraviolet absorber, a rust inhibitor, a silane coupling agent, and inorganic particles may be suitably contained as required.
Further, if necessary, a reaction catalyst (tertiary amine compound, quaternary ammonium compound, tin laurate compound, etc.) may be suitably contained.
< laminated Structure >
The present adhesive sheet 1 may be a sheet formed of a single layer, or may be a multilayer sheet formed by laminating 2 or more layers.
When the present pressure-sensitive adhesive sheet 1 is a multilayer pressure-sensitive adhesive sheet, it is sufficient to provide a pressure-sensitive adhesive layer formed from the present pressure-sensitive adhesive composition 1 (referred to as "present pressure-sensitive adhesive layer 1"), and for example, when a pressure-sensitive adhesive sheet having a laminate structure including an intermediate layer and an outermost layer is formed, the outermost layer is preferably formed from the present pressure-sensitive adhesive composition 1, and particularly preferably from the pressure-sensitive adhesive compositions (1-I) and (1-II).
The pressure-sensitive adhesive sheet 1 may be a sheet having a structure in which the pressure-sensitive adhesive layer 1 formed from the pressure-sensitive adhesive composition 1 is formed on a release film, or a sheet having a structure in which the pressure-sensitive adhesive layer 1 is formed on an adherend, for example, a component member for an image display device, which will be described later. For example, the present adhesive layer 1 may be formed on a substrate to form a substrate-attached adhesive sheet, or may be a substrate-free adhesive sheet having no substrate. Further, the double-sided pressure-sensitive adhesive sheet may have the present pressure-sensitive adhesive layer 1 on both the upper and lower sides, or may have the present pressure-sensitive adhesive layer 1 only on one of the upper and lower sides.
< thickness >
From the viewpoint of not hindering the thinning of the image display device, the thickness of the maximum thickness portion of the adhesive sheet 1 is preferably 250 μm or less. In other words, the present pressure-sensitive adhesive sheet 1 may be a sheet having a uniform thickness or a sheet having a locally different thickness, and when the sheet has a non-uniform thickness, the thickness of the portion having the largest thickness is preferably 250 μm or less.
From the viewpoint of not impairing the adhesion force to an adherend and the impact absorbability, the thickness of the maximum thickness portion is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more.
< use >
The present adhesive sheet 1 may be used as it is, or may be used as follows. In addition, the method of using the adhesive sheet 1 is not limited.
The present adhesive sheet 1 may be provided in the form of an adhesive sheet laminate having a structure in which a release film is laminated on one surface or both surfaces of the present adhesive sheet 1, for example.
< laminate 1 for constituting image display device >
Further, a laminate for image display device configuration having a configuration in which 2 image display device-constituting members are laminated with the present adhesive sheet 1 interposed therebetween (hereinafter referred to as "laminate 1 for image display device configuration") may be prepared and provided.
The laminate 1 for constituting an image display device can be produced, for example, by the following method: the adhesive sheet 1 is laminated with an image display device-constituting member and another image display device-constituting member interposed therebetween, and the adhesive sheet 1 is photocured by irradiating the adhesive sheet 1 with light through the former image display device-constituting member.
Examples of the laminate 1 for constituting the image display device include: examples of the laminate having the structure of protective panel/present adhesive sheet 1/polarizing film include, for example, image display panel/present adhesive sheet 1/touch panel, image display panel/present adhesive sheet 1/protective panel, image display panel/present adhesive sheet 1/touch panel/present adhesive sheet 1/protective panel, polarizing film/present adhesive sheet 1/touch panel/present adhesive sheet 1/protective panel, and the like.
As for the protective panel and the image display panel, a touch panel sensor may be incorporated in the protective panel or the image display panel itself.
< present image display apparatus 1>
An image display device (hereinafter referred to as "the present image display device 1") can be configured using the present adhesive sheet 1 or the present image display device configuration laminate.
An example of a preferable manufacturing method of the image display device 1 will be described.
First, the present adhesive sheet 1 is heated and thermally melted, and a component member for an image display device and another component member for an image display device are laminated with the present adhesive sheet 1 interposed therebetween. At this stage, the present adhesive sheet 1 is moderately flexible, and therefore can sufficiently follow the level difference while maintaining storage stability.
Next, light such as ultraviolet light is irradiated from the outside of the image display device constituent member. Thus, the crosslinking reaction can be carried out to allow photocuring, and excellent peeling resistance and foaming resistance can be achieved.
Examples of the 2 image display device components include: a computer, a mobile terminal (PDA), a game machine, a Television (TV), a car navigation system, a touch panel, a tablet, or the like, and an image display device such as an LCD, a PDP, or an EL. More specifically, examples thereof include: a touch panel, an image display panel, a surface protection panel, and a polarizing film, or a laminate formed by combining two or more of them.
[ adhesive sheet 2]
An adhesive sheet (referred to as "present adhesive sheet 2") according to another embodiment of the present invention is an adhesive sheet including: a pressure-sensitive adhesive sheet which comprises a (meth) acrylic copolymer (A) as a base polymer and is partially photo-cured, wherein any part of the pressure-sensitive adhesive sheet has a sheet portion (referred to as a "soft portion") having a gel fraction of less than 1% and a sheet portion (referred to as a "hard portion") having a gel fraction of 40% or more.
The gel fraction can be measured by extraction with a solvent. Specifically, when the polymer constituting the adhesive sheet is not crosslinked, a solvent (good solvent) dissolving the polymer is selected, and then the adhesive sheet is extracted using the solvent. Examples of the solvent used in the extraction include: vinyl acetate, acetone, toluene, xylene, lower alcohols, tetrahydrofuran, and the like.
The temperature and time for extraction can be set arbitrarily. After the extraction operation, the component (swollen component) which is not dissolved in the solvent may be recovered and dried, and then the weight fraction thereof may be measured. Specific extraction methods include: soxhlet extraction, the method described in the examples described below, and the like.
When the gel fraction is high, the pressure-sensitive adhesive sheet can be suitably crushed and then subjected to extraction.
For example, in a display screen of a cellular phone, a protective panel made of plastic is laminated on a liquid crystal panel display (LCD) by laminating a polarizing film or the like thereon and further laminating an adhesive or a sheet thereon, and a non-light-transmitting portion such as a printed portion is usually provided on a peripheral edge portion of a back surface of the protective panel.
When such a protective panel with a printed portion is bonded to another image display device component such as a touch panel with an adhesive sheet interposed therebetween, the adhesive sheet fills the corners following the difference in print level, and if the surface of the adhesive sheet is not smooth, the adhesive sheet is strained or deformed when the image display component is bonded, and display unevenness causes deterioration in visibility, and therefore flexibility is required for the adhesive sheet. Further, there is a problem that strain or deformation is likely to occur in the pressure-sensitive adhesive sheet due to a difference in print level or the like.
On the other hand, it is required that the exposed adhesive surface is not sticky even under extreme environments such as high temperature and high humidity. In addition, the pressure-sensitive adhesive sheet is required to have a high cohesive force that prevents peeling and foaming of the pressure-sensitive adhesive sheet after the image display device constituent member is bonded to the pressure-sensitive adhesive sheet via the pressure-sensitive adhesive sheet.
Accordingly, the present invention is intended to provide a novel adhesive sheet 2 which, for example, even when it is bonded to a component member for an image display device having a light-opaque portion such as a printed portion and a light-transmissive portion in a bonding surface, can obtain conformability to a step portion and the like and surface flatness, does not cause strain or deformation even in the light-opaque portion, can firmly bond adherends to each other with high cohesive force, and can prevent the exposed adhesive surface from becoming sticky in an extreme environment such as a high-temperature high-humidity environment.
The present pressure-sensitive adhesive sheet 2 can obtain conformability to stepped portions and the like and surface flatness by the soft portion having a gel fraction of less than 1%, and can relax strain and deformation in the sheet, while can firmly bond adherends to each other with high cohesive force without causing the adhesive surface to be sticky by the hard portion having a gel fraction of 40% or more.
Therefore, for example, even when the adhesive sheet is bonded to a component member for an image display device having a light-opaque portion such as a printed portion and a light-transmissive portion in a bonding surface, the adhesive sheet as a whole can have conformability to a printed step portion and surface flatness, and can be firmly bonded to each other with high cohesive force without causing strain or deformation in the light-opaque portion. Further, by making the exposed adhesive surface a hard portion, the exposed adhesive surface can be made less sticky even under extreme environments such as high temperature and high humidity.
The present adhesive sheet 2 may have the soft portion and the hard portion on the sheet surface of the adhesive sheet as shown in fig. 1 or 2, or may have the hard portion on at least one end surface of the adhesive sheet as shown in fig. 3 (a) (B) or 5. In this case, the sheet surface of the pressure-sensitive adhesive sheet may be a soft portion or a hard portion. As shown in fig. 5, the adhesive sheet may have the hard portion on at least one end surface thereof, which is wound in a roll.
The "base polymer" in the present invention means a resin that constitutes a main component of the adhesive composition forming each layer. The specific content of the base polymer is not limited, and is defined as a resin that accounts for 50 mass% or more, 80 mass% or more, and 90 mass% or more (including 100 mass%) of the resins contained in the adhesive composition forming each layer. When the base polymer is two or more, the total amount thereof corresponds to the above content.
The gel fraction of the soft portion is preferably less than 1%, more preferably less than 0.8%, even more preferably less than 0.5%, from the viewpoint of conformability to the uneven portion, surface flatness, and further relaxation of strain and deformation in the sheet.
On the other hand, the gel fraction of the hard portion is preferably 40% or more, more preferably 45% or more, and particularly preferably 50% or more, from the viewpoint of exhibiting high cohesive force to improve adhesiveness and preventing the adhesive surface from becoming sticky even under extreme environments such as high temperature and high humidity.
Further, since the soft part has appropriate flexibility and self-adhesiveness in a normal temperature range when the glass transition temperature (Tg S) of the soft part is-70 to-10 ℃ as measured by a Differential Scanning Calorimeter (DSC), the Tg of the soft part is preferably-70 to-10 ℃, more preferably-65 ℃ or-15 ℃ or less, even more preferably-60 ℃ or-20 ℃ or less.
On the other hand, since a high cohesive force can be obtained when the glass transition temperature (Tg H) of the hard portion measured by a Differential Scanning Calorimeter (DSC) is-60 to +10 ℃, the Tg of the hard portion is preferably-60 to +20 ℃, more preferably-55 ℃ or higher or +15 ℃ or lower, and particularly preferably-50 ℃ or higher or +10 ℃ or lower.
Further, when the difference (Tg [ H ] -Tg [ S ]) between the glass transition temperature (Tg [ S ]) of the soft portion and the glass transition temperature (Tg [ H ]) of the hard portion is 3 ℃ or more, both contradictory properties of flexibility and cohesive force can be satisfied at a higher level, and as a result, both followability to the surface to be bonded at the time of bonding and excellent reliability against foaming after the laminate is produced can be satisfied, and therefore, this is preferable. Therefore, the difference (Tg H-Tg S) between the glass transition temperature (Tg S) of the soft portion and the glass transition temperature (Tg H) of the hard portion is preferably 3 ℃ or higher, more preferably 5 ℃ or higher, and particularly preferably 7 ℃ or higher.
(ASKER hardness of Soft portion)
The ASKER hardness (c) of the soft portion in the present adhesive sheet 2 is preferably 10 or more because appropriate hardness can be obtained in terms of cutting processability and ease of curling. Further, it is preferable that the ASKER hardness (c) is less than 60 because appropriate flexibility and adhesion to an adherend can be obtained.
From the above viewpoint, the ASKER hardness (c) of the soft portion in the present adhesive sheet 2 is preferably 10 or more and less than 60, more preferably 15 or more and 55 or less, and particularly preferably 20 or more and 50 or less.
(ASKER hardness of hard portion)
By setting the ASKER hardness (d) of the hard portion in the present adhesive sheet 2 to 40 or more, a laminate having high cohesive force, excellent shape stability and foam resistance reliability can be obtained. Further, it is preferable that the ASKER hardness (d) is less than 90 because a laminate excellent in impact resistance can be obtained without becoming excessively brittle.
From the above viewpoint, the ASKER hardness (d) of the hard portion in the present adhesive sheet 2 is preferably 40 or more and less than 90, more preferably 43 or more or 88 or less, and particularly preferably 45 or more or 85 or less.
Further, in the present adhesive sheet 2, it is preferable that the (d) to (c) are 20 or more because the following property to the adherend surface at the time of bonding and the excellent reliability of the foaming resistance after the laminate is produced can be both satisfied.
From the above viewpoint, in the present adhesive sheet 2, the difference ((d) - (c)) between the ASKER hardness (c) of the soft portion and the ASKER hardness (d) of the hard portion is preferably 20 or more, more preferably 20 or more or 80 or less, and particularly preferably 25 or more or 75 or less.
In the present adhesive sheet 2, in order to adjust the ask hardness (c) of the soft portion and the ask hardness (d) of the hard portion, the composition ratio of the crosslinking agent and the photopolymerization initiator may be adjusted in the composition and the production method, or the light irradiation amount to the adhesive composition may be adjusted. In addition, the method is not limited to this.
(180 ℃ Peel force of Soft portion)
When the 180 ° peel force of the soft portion in the present pressure-sensitive adhesive sheet 2 is 3N/cm or more, the sheet has moderate adhesion to an adherend at normal temperature, and is excellent in bonding workability, and therefore, it is preferable.
From the above viewpoint, the 180 ° peel force of the soft portion in the present adhesive sheet 2 is preferably 3N/cm or more, more preferably 20N/cm or less, and particularly preferably 4N/cm or more or 15N/cm or less.
(180 degree peeling force of hard portion)
The hard portion of the present adhesive sheet 2 preferably has a 180 ° peel force of 5N/cm or more, because excellent foaming/peeling resistance can be obtained.
From the above viewpoint, the 180 ° peel force of the hard portion in the present adhesive sheet 2 is preferably 5N/cm or more, more preferably 25N/cm or less, and particularly preferably 6N/cm or more or 20N/cm or less.
In the present adhesive sheet 2, in order to adjust the 180 ° peel force of the soft portion and the hard portion, the kind and composition ratio of the crosslinking agent and the photopolymerization initiator, or the heating/pressurizing conditions at the time of bonding and the light irradiation conditions after bonding may be adjusted in the composition and the production method. In addition, the method is not limited to this.
(40 ℃ C. holding Power of Soft portion)
By setting the holding force of the soft part in the present adhesive sheet 2 at a temperature of 40 ℃ to a deflection length of less than 10mm, excellent workability and storage stability can be obtained.
From the above viewpoint, the holding force of the soft part in the present adhesive sheet 2 at a temperature of 40 ℃ is preferably less than 10mm, more preferably less than 8mm, and still more preferably less than 5mm in offset length.
(Soft portion 70 ℃ C. Retention force)
The holding power at a temperature of 70 ℃ of the soft part in the present adhesive sheet 2 is preferable because when the sticking surface is deviated and a weight is dropped in less than 10 minutes, excellent adhesion to an adherend and excellent uneven absorbency can be obtained at the time of sticking.
From the above viewpoint, the holding force at a temperature of 70 ℃ of the soft part in the present adhesive sheet 2 is preferably such that the sticking surface shifts and the weight drops in less than 10 minutes, more preferably such that the sticking surface shifts and the weight drops in less than 8 minutes, and even more preferably such that the sticking surface shifts and the weight drops in less than 6 minutes.
(40 ℃ or 70 ℃ holding power of hard portion)
The holding force of the hard portion in the present adhesive sheet 2 at both temperatures of 40 ℃ and 70 ℃ is preferably less than 1mm, more preferably less than 0.7mm, and still more preferably less than 0.5mm in offset length.
By setting the holding power at 40 ℃ and 70 ℃ of the hard portion in the present adhesive sheet 2 to the above range, high cohesive force, shape stability under a hot and humid environment, and reliability in foaming resistance can be obtained.
< method for producing adhesive sheet 2>
The present adhesive sheet 2 can be produced as follows.
(1) In the case of a photocurable adhesive sheet, when a portion to be a soft portion is shielded by an opaque member, i.e., a member through which light used for photocuring does not pass, and light is irradiated, a portion covered with the opaque member may be a soft portion, and a portion not covered with the opaque member, i.e., a portion irradiated with light, may be photocured to be a hard portion.
(2) Further, when light is irradiated to the end surface portion of the adhesive sheet and light is not irradiated to the portion other than the end surface portion, the end surface portion may be a hard portion and the other portion may be a soft portion.
For example, the end surface portion of the adhesive sheet may be irradiated with light from a vertical direction, a horizontal direction, or an obliquely upward and downward direction (provided such that the front surface and the back surface of the sheet are arranged along the vertical upward and downward direction), or the end surface portion of the adhesive sheet may be irradiated with light from a vertical direction, a horizontal direction, or an obliquely upward and downward direction, with sheets that do not pass light used for photocuring being laminated in advance on one or both of the front surface and the back surface of the adhesive sheet. When light is irradiated in this manner, the end surface portion of the adhesive sheet can be photocured. In this case, as the sheet through which light used for photocuring does not pass, a release sheet through which light used for photocuring does not pass is particularly preferably used as follows: examples of the release sheet include release sheets using polyethylene terephthalate as a base polymer, and release sheets using a polyethylene terephthalate film or a polyolefin film mixed with an ultraviolet absorber or a film coated with an ultraviolet absorber on the surface thereof.
When light is irradiated, the end surface portion and the peripheral portion thereof may be hard portions.
(3) In addition, adhesive sheets each having a desired gel fraction are prepared separately in advance, and the soft portion and the hard portion may be formed in the adhesive sheet by integrating the two.
< adhesive sheet X >
The adhesive sheet 2 can be formed by partially photocuring the adhesive sheet X as follows. The present adhesive sheet 2 is not limited to the adhesive sheet X described below.
From the viewpoint that hot-melt property can be exhibited in the state before photocuring, the gel fraction (a) before photocuring of the adhesive sheet X is less than 1%, preferably less than 0.8%, particularly preferably less than 0.5%.
In addition, the gel fraction (b) of the pressure-sensitive adhesive sheet X after photocuring is preferably 40% or more, more preferably 45% or more or 95% or less, and particularly preferably 50% or more or 90% or less, from the viewpoint of obtaining high cohesive strength after photocuring and obtaining reliability in foaming resistance under a moist heat environment.
In order to adjust the gel fraction (a) before photocuring and the gel fraction (b) after photocuring to the above-mentioned values, the composition and the composition ratio of the crosslinking agent and the photopolymerization initiator in the production method may be adjusted, or the temperature and the irradiation light amount during the processing may be adjusted. In addition, the method is not limited to this.
< adhesive composition 2>
A resin composition (hereinafter referred to as "present adhesive composition 2") that can be suitably used for forming the adhesive sheet X will be described. This is merely an example, and is not limited thereto.
The present pressure-sensitive adhesive composition 2 is preferably a photocurable pressure-sensitive adhesive composition. Among these, preferred is a resin composition containing a (meth) acrylic copolymer (2-A), a crosslinking agent (2-B), and a photopolymerization initiator (2-C).
The composition of the adhesive composition used to form the adhesive sheet 2 is not limited as long as the gel fraction after attachment can be made different depending on the site in the adhesive sheet as described above.
Here, the present adhesive sheet 2 is particularly preferably a photocurable adhesive sheet which can be held in a sheet form in a normal state, has a hot-melt property that melts or flows when heated in an uncrosslinked state, and can be photocured.
When the sheet-like adhesive is held in a normal state, handling is easier than with a liquid adhesive, filling with a liquid can be omitted, and productivity is particularly excellent.
Further, since positioning at the time of sticking is easy and handling is excellent in a property (referred to as "tackiness") that the adhesive has an appropriate adhesiveness in a normal state, that is, in the vicinity of room temperature, that is, can be adhered to an adherend with a slight force in a short time, it is preferable to have tackiness in a normal state, that is, in the vicinity of room temperature, and more preferably, to have tackiness even in a relatively low temperature region of-5 ℃ to 20 ℃.
In addition, in the case of hot melt which melts or flows when heated, the binder can be filled so as to follow up the uneven portions such as the printing step by softening or flowing the hot melt by heating, and therefore, the binder can be filled without causing foaming or the like.
Further, when photo-curable, strong adhesion can be achieved by final photo-curing.
In order to produce a pressure-sensitive adhesive sheet which can be held in a sheet form in a normal state, has a hot-melt property that melts or flows when heated in an uncrosslinked state, and can be photo-cured, for example, a single-layer pressure-sensitive adhesive sheet may be produced from the pressure-sensitive adhesive composition (2-I) or (2-II) described below. On the other hand, in the case of a multilayer adhesive sheet, for example, there are: 2 kinds of 2 layers obtained by laminating an adhesive layer formed of the adhesive composition (2-I) or (2-II) and an adhesive layer formed of another adhesive composition; 2 kinds of 3 layers each having an adhesive layer formed of the adhesive composition (2-I) or (2-II) disposed on the front and back surfaces thereof with the intermediate resin layer interposed therebetween; and 3 types of 3 layers in which an adhesive layer composed of the adhesive composition (2-I) or (2-II), an intermediate layer composed of an intermediate resin composition, and an adhesive layer composed of another adhesive composition are laminated in this order.
In addition, the adhesive composition used for forming the present adhesive sheet 2 is not limited to the adhesive composition (2-I) or (2-II).
< adhesive composition (2-I) >
The pressure-sensitive adhesive composition (2-I) includes a resin composition containing an acrylic copolymer (2-A1) composed of a graft copolymer having a macromonomer as a branch component, a crosslinking agent (2-B1), and a photopolymerization initiator (2-C1).
(acrylic copolymer (2-A1))
The acrylic copolymer (2-A1) as the base polymer may be a graft copolymer having a macromonomer as a branch component.
(Main component)
The main component of the acrylic copolymer (2-a1) is preferably composed of a copolymer component containing a repeating unit derived from a (meth) acrylate ester.
The glass transition temperature of the copolymer constituting the main component of the acrylic copolymer (2-A1) is preferably-70 to 0 ℃.
In this case, the glass transition temperature of the copolymer component constituting the main component means the glass transition temperature of a polymer obtained by copolymerizing only the monomer components constituting the main component of the acrylic copolymer (2-a 1). Specifically, the value is calculated by the Fox equation based on the glass transition temperature and the composition ratio of the polymer obtained from the homopolymer of each component of the copolymer.
The Fox equation is a calculated value obtained by the following formula, and can be obtained by using a value described in polymer handbook [ polymer handbook, j.
1/(273+Tg)＝Σ(Wi/(273+Tgi))
[ in the formula, Wi represents the weight percent of the monomer i, and Tgi represents the Tg (. degree. C.) of the homopolymer of the monomer i. ]
Since the glass transition temperature of the copolymer component constituting the main component of the acrylic copolymer (2-A1) affects the flexibility of the pressure-sensitive adhesive composition (2-I) in a room temperature state and the wettability, i.e., the adhesiveness, of the pressure-sensitive adhesive composition (2-I) to an adherend, the glass transition temperature is preferably-70 ℃ to 0 ℃, more preferably-65 ℃ or more or-5 ℃ or less, particularly preferably-60 ℃ or more or-10 ℃ or less, in order to obtain a proper adhesiveness (tackiness) of the pressure-sensitive adhesive composition (2-I) in a room temperature state.
Even when the glass transition temperature of the copolymer component is the same temperature, the viscoelasticity can be adjusted by adjusting the molecular weight. For example, by reducing the molecular weight of the copolymer component, it can be made softer.
Examples of the (meth) acrylate monomer contained in the main component of the acrylic copolymer (2-a1) include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isoamyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl acrylate, hexyl (meth) acrylate, hexyl (meth) acrylate, hexyl (, Stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, isobornyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 3,5, 5-trimethylcyclohexyl acrylate, p-cumylphenol EO-modified (meth) acrylate, dicyclopentyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, benzyl (meth) acrylate, and the like. Hydroxyl-containing (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and glycerol (meth) acrylate having a hydrophilic group, an organic functional group and the like, (meth) acrylic acid, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxypropylphthalic acid, 2- (meth) acryloyloxyethylmaleic acid, 2- (meth) acryloyloxypropylmaleic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxypropylsuccinic acid, crotonic acid, fumaric acid, maleic acid, and the like, Carboxyl group-containing monomers such as itaconic acid, monomethyl maleate and monomethyl itaconate, anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, glycidyl (meth) acrylate, glycidyl alpha-ethacrylate, epoxy group-containing monomers such as 3, 4-epoxybutyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, amino group-containing (meth) acrylate monomers such as diethylaminoethyl (meth) acrylate, and (meth) acrylamide, amide group-containing monomers such as N-t-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide, maleimide and maleimide, and heterocyclic basic monomers such as vinylpyrrolidone, vinylpyridine and vinylcarbazole.
In addition, various vinyl monomers such as styrene, t-butylstyrene, α -methylstyrene, vinyltoluene, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, alkyl vinyl ether, hydroxyalkyl vinyl ether, and alkyl vinyl monomer copolymerizable with the above acrylic monomer and methacrylic monomer can also be suitably used.
The main component of the acrylic copolymer (2-a1) preferably contains a hydrophobic (meth) acrylate monomer and a hydrophilic (meth) acrylate monomer as constituent units.
Since the main component of the acrylic copolymer (2-a1) is composed of only a hydrophobic monomer, the main component tends to be whitened by moist heat, it is preferable to introduce a hydrophilic monomer into the main component to prevent whitening by moist heat.
Specifically, the main component of the acrylic copolymer (2-a1) includes a copolymer component obtained by random copolymerization of a hydrophobic (meth) acrylate monomer, a hydrophilic (meth) acrylate monomer, and a polymerizable functional group at the end of a macromonomer.
Here, the hydrophobic (meth) acrylate monomer is preferably an alkyl ester having no polar group (excluding methyl acrylate), and examples thereof include: n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, and mixtures thereof, Isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, methyl methacrylate.
Examples of the hydrophobic vinyl monomer include: vinyl acetate, styrene, t-butyl styrene, alpha-methyl styrene, vinyl toluene, alkyl vinyl monomers, and the like.
The hydrophilic (meth) acrylate monomer is preferably methyl acrylate or an ester having a polar group, and examples thereof include: hydroxyl group-containing (meth) acrylates such as methyl acrylate, meth) acrylic acid, tetrahydrofurfuryl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and glycerol (meth) acrylate, (meth) acrylic acid, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxypropylphthalic acid, 2- (meth) acryloyloxyethylmaleic acid, 2- (meth) acryloyloxypropylmaleic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxypropylsuccinic acid, crotonic acid, maleic acid, and mixtures thereof, Carboxyl group-containing monomers such as fumaric acid, maleic acid, itaconic acid, monomethyl maleate and monomethyl itaconate, anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, epoxy group-containing monomers such as glycidyl (meth) acrylate, glycidyl α -ethacrylate, 3, 4-epoxybutyl (meth) acrylate, alkoxy polyalkylene glycol (meth) acrylates such as methoxypolyethylene glycol (meth) acrylate, N-dimethylacrylamide, hydroxyethylacrylamide, and the like.
(Branch component: macromonomer)
As the graft component of the graft copolymer, the acrylic copolymer (2-A1) is preferably one in which a macromonomer is introduced and which contains a repeating unit derived from the macromonomer.
The macromonomer is a high molecular monomer having a polymerizable functional group at the end and a high molecular weight skeleton component.
The glass transition temperature (Tg) of the macromonomer is preferably higher than the glass transition temperature of the copolymer component constituting the above-mentioned acrylic copolymer (2-A1).
Specifically, the glass transition temperature (Tg) of the macromonomer affects the heating melting temperature (hot melt temperature) of the adhesive composition (2-I), and therefore the glass transition temperature (Tg) of the macromonomer is preferably 30 ℃ to 120 ℃, more preferably 40 ℃ or more or 110 ℃ or less, further preferably 50 ℃ or more or 100 ℃ or less.
When the glass transition temperature (Tg) is adjusted as described above, it is possible to maintain excellent processability and storage stability by adjusting the molecular weight, and it is possible to adjust the glass transition temperature so that hot melting occurs at around 80 ℃.
The glass transition temperature of the macromonomer is the glass transition temperature of the macromonomer itself and can be measured by a Differential Scanning Calorimeter (DSC). (temperature rising Rate: 5 ℃ C./minute, Tg was measured from the inflection point of the base line shift)
In addition, in the room temperature state, the branch components are mutually adsorbed, as a binder composition can be maintained as a physical crosslinking state, and by heating to an appropriate temperature, the physical crosslinking can be released and fluidity can be obtained, therefore, the adjustment of the molecular weight and content of the macromonomer is preferred.
From the above viewpoint, the macromonomer is preferably contained in the acrylic copolymer (2-a1) at a ratio of 5 to 30% by mass, of which 6% by mass or more or 25% by mass or less is preferable, and 8% by mass or more or 20% by mass or less is preferable.
In addition, the number average molecular weight of the macromonomer is preferably 500 or more and less than 8000, among them preferably 800 or more or less than 7500, among them preferably 1000 or more or less than 7000.
As the macromonomer, conventionally produced one (for example, macromonomer produced by east asian synthesis company) can be used.
The high molecular weight backbone component of the macromonomer is preferably an acrylic polymer or a vinyl polymer.
Examples of the high molecular weight skeleton component of the macromonomer include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, isopropyl (meth) acrylate, hexyl (ethyl (meth) acrylate, hexyl (ethyl acrylate, hexyl (meth) acrylate, hexyl (ethyl (meth) acrylate, hexyl (ethyl (methyl (ethyl acrylate, hexyl (meth) acrylate, hexyl (ethyl acrylate, hexyl (meth) acrylate, hexyl (ethyl acrylate, hexyl (, (meth) acrylate monomers such as stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, isobornyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 3,5, 5-trimethylcyclohexyl acrylate, p-cumylphenol EO-modified (meth) acrylate, dicyclopentyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, benzyl (meth) acrylate, hydroxyalkyl (meth) acrylate, meth) acrylic acid, glycidyl (meth) acrylate, (meth) acrylamide, N-dimethyl (meth) acrylamide, (meth) acrylonitrile, alkoxyalkyl (meth) acrylate, alkoxypolyalkylene glycol (meth) acrylate, and the like, Various vinyl monomers such as styrene, t-butylstyrene, α -methylstyrene, vinyltoluene, alkyl vinyl monomer, vinyl acetate, alkyl vinyl ether, hydroxyalkyl vinyl ether, and the like, and these may be used alone or in combination of two or more.
Examples of the terminal polymerizable functional group of the macromonomer include a methacryloyl group, an acryloyl group, and a vinyl group.
(crosslinking agent (2-B1))
As the crosslinking agent (2-B1), for example, a crosslinking agent having 2 or more crosslinkable groups such as an epoxy group, an isocyanate group, an oxetanyl group, a silanol group, and a (meth) acryloyl group can be suitably selected. Among them, polyfunctional (meth) acrylates having 2 or more (meth) acryloyl groups, preferably 3 or more (meth) acryloyl groups among them, and (meth) acrylates having epoxy groups, isocyanate groups, and silanol groups are preferable in terms of reactivity and strength of the resulting cured product.
After the image display device constituting members are bonded and integrated, the sheet loses its hot-melt property by crosslinking the crosslinking agent (2-B1) in the adhesive material, and instead, exhibits a high cohesive force in a high-temperature environment, thereby obtaining excellent reliability in foaming resistance.
Examples of such (meth) acrylates include: 1, 4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerol glycidyl ether di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, bisphenol A polyalkoxy di (meth) acrylate, bisphenol F polyalkoxy di (meth) acrylate, polyalkylene glycol di (meth) acrylate, trimethylolpropane triethoxy ethyl (meth) acrylate, epsilon-caprolactone-modified tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, propylene glycol di (meth) acrylate, and/or mixtures thereof, Ethoxylated pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyethylene glycol di (meth) acrylate, tris (acryloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, di (meth) acrylate of the epsilon-caprolactone adduct of hydroxypivalic acid neopentyl glycol, trimethylolpropane tri (meth) acrylate, alkoxylated trimethylolpropane tri (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, and mixtures thereof, Ultraviolet-curable polyfunctional monomers such as ditrimethylolpropane tetra (meth) acrylate; and polyfunctional acrylic oligomers such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyether (meth) acrylate, isocyanate (meth) acrylate, 1- (bis (meth) acryloyloxymethyl) ethyl isocyanate, 2- (2- (meth) acryloyloxyethyloxy) ethyl isocyanate, glycidyl (meth) acrylate, hydroxyethyl acrylate glycidyl ether, hydroxypropyl (meth) acrylate glycidyl ether, hydroxybutyl (meth) acrylate glycidyl ether, and the like.
Among the above, polyfunctional monomers or oligomers containing a polar functional group such as a hydroxyl group are preferable from the viewpoint of improving the adhesion to an adherend and the effect of suppressing whitening by heat under moisture.
Among them, polyfunctional (meth) acrylates having a hydroxyl group or a carboxyl group are preferably used.
Therefore, from the viewpoint of preventing moist heat whitening, it is preferable to contain a hydrophobic acrylate monomer and a hydrophilic acrylate monomer as the main component of the acrylic copolymer (2-a1), that is, the graft copolymer, and further, it is preferable to use a polyfunctional (meth) acrylate having a hydroxyl group as the crosslinking agent (2-B).
The content of the crosslinking agent (2-B1) is not particularly limited. The amount of the acrylic copolymer (2-A1) is 0.5 to 20 parts by mass, preferably 1 part by mass or more and 15 parts by mass or less, and more preferably 2 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the acrylic copolymer.
By containing the crosslinking agent (2-B1) within the above range, the shape stability of the present adhesive sheet 2 in an uncrosslinked state and the reliability of the foaming resistance in the crosslinked adhesive material can be both satisfied. In addition, the balance with other elements may be out of the range.
(photopolymerization initiator (2-C1))
The photopolymerization initiator (2-C1) functions as a reaction initiation assistant in the crosslinking reaction of the crosslinking agent (2-B1).
The photopolymerization initiator may be any of those known in the art. Among them, a photopolymerization initiator which is sensitive to ultraviolet rays having a wavelength of 380nm or less is preferable from the viewpoint of easiness of control of the crosslinking reaction.
On the other hand, light induced by the photopolymerization initiator which is sensitive to light having a wavelength longer than 380nm is preferable in that it easily reaches the depth of the adhesive sheet 2.
Photopolymerization initiators are roughly classified into two types according to the mechanism of radical generation: a cleavage type photopolymerization initiator capable of generating radicals by breaking and decomposing a single bond of the photopolymerization initiator itself; and a hydrogen abstraction type photopolymerization initiator which forms an excited complex with a hydrogen donor in the system by the photo-excited initiator and can transfer hydrogen from the hydrogen donor.
Among these, the cleavage type photopolymerization initiators decompose to form other compounds when radicals are generated by irradiation with light, and once excited, lose their functions as reaction initiators. Therefore, the binder after the completion of the crosslinking reaction is preferably because the binder does not remain as an active species any longer, and there is no possibility that the binder is subjected to unexpected light deterioration or the like.
On the other hand, since the hydrogen abstraction-type photopolymerization initiator does not generate a decomposition product such as a cleavage-type photopolymerization initiator when radical generation reaction is caused by irradiation with active energy rays such as ultraviolet rays, it is not likely to become a volatile component after the reaction is completed, and is useful in that damage to an adherend can be reduced.
Examples of the cleavage type photoinitiator include: 2, 2-dimethoxy-1, 2-diphenylethan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- (4- (2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- [4- {4- (2-hydroxy-2-methyl-propionyl) benzyl } phenyl ] -2-methyl-propan-1-one, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone); poly (1-hydroxy-2-methyl-1-one, poly (2-hydroxy-2-methyl-1-propanone); poly (2-hydroxy-2-1-methyl-1-methyl-propanone); poly (1-hydroxy-2-methyl-1-propanone); poly (1-methyl-propanone); poly (1-hydroxy-1-methyl-propanone), Methyl phenylglyoxylate, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropan-1-one, 2- (dimethylamino) -2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholino) phenyl ] -1-butanone, bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, derivatives of these, and the like.
Examples of the hydrogen abstraction photoinitiator include: benzophenone, 4-methyl-benzophenone, 2,4, 6-trimethylbenzophenone, 4-phenylbenzophenone, 3' -dimethyl-4-methoxybenzophenone, 4- (meth) acryloyloxybenzophenone, methyl 2-benzoylbenzoate, methyl benzoylformate, bis (2-phenyl-2-oxoacetic acid) oxydiethylene, 4- (1, 3-acryloyl-1, 4,7,10, 13-pentaoxotridecyl) benzophenone, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2, 4-dimethylthioxanthone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, derivatives thereof, and the like.
The photopolymerization initiator is not limited to the above examples. Any one of the above-listed cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators may be used, or two or more thereof may be used in combination.
The content of the photopolymerization initiator (2-C1) is not particularly limited. For reference, it is preferable that the acrylic copolymer (2-A1) is contained in a ratio of 0.1 to 10 parts by mass, 0.5 part by mass or more and 5 parts by mass or less, and 1 part by mass or more and 3 parts by mass or less, based on 100 parts by mass of the acrylic copolymer.
By setting the content of the photopolymerization initiator (2-C1) to the above range, appropriate response sensitivity to active energy rays can be obtained.
(other Components)
The pressure-sensitive adhesive composition (2-I) may contain, as components other than those described above, known components usually blended in pressure-sensitive adhesive compositions. For example, various additives such as a tackifier resin, an antioxidant, a light stabilizer, a metal deactivator, an antioxidant, a moisture absorbent, a polymerization inhibitor, an ultraviolet absorber, a rust inhibitor, a silane coupling agent, and inorganic particles may be suitably contained as required.
Further, if necessary, a reaction catalyst (tertiary amine compound, quaternary ammonium compound, tin laurate compound, etc.) may be suitably contained.
< adhesive composition (2-II) >
The pressure-sensitive adhesive composition (2-II) includes a resin composition containing a (meth) acrylic copolymer (2-A2), a crosslinking agent (2-B2), and a photopolymerization initiator (2-C2), wherein the (meth) acrylic copolymer (2-A2) contains a monomer a having a glass transition temperature (Tg) of less than 0 ℃, a monomer B having a glass transition temperature (Tg) of 0 ℃ or more and less than 80 ℃, and a monomer C having a glass transition temperature (Tg) of 80 ℃ or more, and the ratio of a: b: c is 10-40: 90-35: a (meth) acrylate copolymer or an ethylene copolymer having a weight average molecular weight of 50000 to 400000, which is obtained by copolymerization at a molar ratio of 0 to 25.
The number average molecular weight and the weight average molecular weight are values converted using Gel Permeation Chromatography (GPC) and polystyrene as a standard substance.
((meth) acrylic copolymer (2-A2))
The (meth) acrylic copolymer (2-a2) as the base polymer is preferably a (meth) acrylate copolymer or an ethylene copolymer.
The weight average molecular weight of the (meth) acrylate copolymer or the ethylene copolymer is preferably 50000 to 400000, more preferably 60000 or more and 350000 or less, and still more preferably 70000 or more and 300000 or less, from the viewpoint of satisfying both the shape retention property in a room temperature state and the hot-melt property.
The physical properties such as glass transition temperature (Tg) and molecular weight of the acrylate copolymer can be appropriately adjusted by appropriately selecting the kind and composition ratio of the acrylic monomer and methacrylic monomer used for the preparation thereof, and further the polymerization conditions.
In this case, examples of the acrylic monomer constituting the acrylic ester copolymer include 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, n-butyl acrylate, ethyl acrylate, and the like as a main raw material.
In addition to these, a (meth) acrylic monomer having various functional groups may be copolymerized with the above acrylic monomer for the purpose of imparting cohesive force, imparting polarity, and the like.
Examples of the (meth) acrylic monomer having such a functional group include methyl methacrylate, methyl acrylate, hydroxyethyl acrylate, acrylic acid, glycidyl acrylate, N-substituted acrylamide, acrylonitrile, methacrylonitrile, fluorine-containing alkyl acrylate, and organic silyl acrylate.
On the other hand, examples of the ethylene copolymer include ethylene copolymers obtained by further polymerizing various vinyl monomers such as vinyl acetate, alkyl vinyl ether, and hydroxyalkyl vinyl ether copolymerizable with the above acrylic monomer and methacrylic monomer.
The (meth) acrylic copolymer (2-a2) of the present adhesive sheet 2 is preferably a mixture of a monomer a having a glass transition temperature (Tg) of less than 0 ℃, a monomer b having a glass transition temperature (Tg) of 0 ℃ or more and less than 80 ℃, and a monomer c having a glass transition temperature (Tg) of 80 ℃ or more, wherein a: b: c is 10-40: 90-35: (meth) acrylate copolymer or ethylene copolymer copolymerized in a molar ratio of 0 to 25.
In this case, the glass transition temperatures (Tg) of the monomers a, b and c are the glass transition temperatures (Tg) when a polymer is produced from the monomers (homopolymerization).
The monomer a is preferably, for example, a (meth) acrylate monomer having the following alkyl structure: the alkyl structure is an alkyl structure having a side chain having 4 or more carbon atoms.
In this case, the side chain having 4 or more carbon atoms may be a straight chain or a branched carbon chain.
More specifically, the monomer a is preferably a (meth) acrylate monomer having a C4-10 linear alkyl structure or a (meth) acrylate monomer having a C6-18 branched alkyl structure.
Here, examples of the "(meth) acrylate monomer having a linear alkyl group structure having 4 to 10 carbon atoms" include: n-butyl acrylate, n-hexyl acrylate, n-octyl acrylate, n-nonyl acrylate, n-decyl acrylate, and the like.
On the other hand, examples of the "(meth) acrylate monomer having a branched alkyl group with 6 to 18 carbon atoms" include: 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-methylhexyl acrylate, isooctyl acrylate, isononyl acrylate, isodecyl methacrylate, and the like.
The monomer b is preferably a (meth) acrylate monomer having 4 or less carbon atoms, a (meth) acrylate monomer having a cyclic skeleton in a side chain, a vinyl monomer having 4 or less carbon atoms, or a vinyl monomer having a cyclic skeleton in a side chain.
Among these, the monomer b is particularly preferably a vinyl monomer having a side chain of 4 or less carbon atoms.
Here, examples of the "c 4 or less (meth) acrylate monomer" include: methyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl acrylate, isobutyl methacrylate, and the like.
Examples of the "(meth) acrylate monomer having a cyclic skeleton in a side chain" include: isobornyl acrylate, cyclohexyl methacrylate, 1, 4-cyclohexanedimethanol monoacrylate, tetrahydrofurfuryl methacrylate, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 3, 5-trimethylcyclohexanol acrylate, cyclic trimethylolpropane formal acrylate, 4-ethoxylated cumylphenol acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentenyl acrylate, and the like.
Examples of the "vinyl monomer having 4 or less carbon atoms" include: vinyl acetate, vinyl propionate, vinyl butyrate, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, and the like.
Examples of the "vinyl monomer having a cyclic skeleton in a side chain" include: styrene, cyclohexyl vinyl ether, norbornyl vinyl ether, norbornenyl vinyl ether, and the like. Among them, a vinyl monomer having a side chain of 4 or less carbon atoms or an acrylate monomer having a side chain of 4 or less carbon atoms is particularly preferable.
The monomer c is preferably a (meth) acrylate monomer having a side chain with 1 or less carbon atoms, or a (meth) acrylate monomer having a side chain with a cyclic skeleton.
Here, examples of the "(meth) acrylate monomer having a side chain with 1 or less carbon atoms" include: methyl methacrylate, acrylic acid, methacrylic acid, and the like.
Examples of the "(meth) acrylate monomer having a cyclic skeleton in a side chain" include: isobornyl methacrylate, 3, 5-trimethylcyclohexyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl methacrylate, dicyclopentenyl methacrylate, and the like.
The (meth) acrylic copolymer (2-a2) comprises a monomer a and a monomer b and a monomer c in a ratio of a: b: c is 10-40: 90-35: 0 to 25, the peak of Tan delta can be adjusted to 0 to 20 ℃, and the sheet shape can be maintained in a normal state, that is, a room temperature state. Further, adhesiveness (referred to as "tackiness") of a degree that can be peeled off can be exhibited. When heated to a temperature at which the adhesive can be melted, the adhesive exhibits fluidity and can be filled into the corners following the step portions of the adhesive surface.
Therefore, from the viewpoint described above, the molar ratio of the monomer a, the monomer b, and the monomer c in the (meth) acrylate ester copolymer or the ethylene copolymer constituting the (meth) acrylic copolymer (2-a2) is a: b: c is 10-40: 90-35: 0 to 25, preferably 13 to 40: 87-35: 0 to 23, preferably 15 to 40: 85-38: 2 to 20.
From the same viewpoint as described above, the molar ratio of the monomer a, the monomer b, and the monomer c in the (meth) acrylate copolymer or the ethylene copolymer constituting the (meth) acrylic copolymer (2-a2) is preferably b > a > c.
(crosslinking agent (2-B2))
By crosslinking the crosslinking agent (2-B2) in the present adhesive sheet 2, the present adhesive sheet 2 can exhibit high cohesive force in a high-temperature environment, and excellent reliability in resistance to foaming can be obtained.
As such a crosslinking agent (2-B2), for example, a crosslinking agent having 2 or more crosslinkable groups such as an epoxy group, an isocyanate group, an oxetanyl group, a silanol group, and a (meth) acryloyl group can be suitably selected. Among them, polyfunctional (meth) acrylates having 2 or more (meth) acryloyl groups, preferably 3 or more (meth) acryloyl groups among them, and (meth) acrylates having epoxy groups, isocyanate groups, and silanol groups are preferable in terms of reactivity and strength of the resulting cured product.
Examples of such (meth) acrylates include: 1, 4-butanediol di (meth) acrylate, glycerol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, bisphenol A polypropoxy di (meth) acrylate, bisphenol F polyethoxy di (meth) acrylate, ethylene glycol di (meth) acrylate, trimethylolpropane triethoxyethyl (meth) acrylate, epsilon-caprolactone-modified tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and mixtures thereof, Propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyethylene glycol di (meth) acrylate, tris (acryloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, ultraviolet-curable polyfunctional monomers such as tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, di (meth) acrylate of an epsilon-caprolactone adduct of hydroxypivalic acid neopentyl glycol, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxy tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and the like; and polyfunctional acrylic oligomers such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyether (meth) acrylate, isocyanate (meth) acrylate, 1- (bis (meth) acryloyloxymethyl) ethyl isocyanate, 2- (2- (meth) acryloyloxyethyloxy) ethyl isocyanate, glycidyl (meth) acrylate, hydroxyethyl acrylate glycidyl ether, hydroxypropyl (meth) acrylate glycidyl ether, and hydroxybutyl (meth) acrylate glycidyl ether.
Among the above, polyfunctional monomers or oligomers having a polar functional group are preferable from the viewpoint of improving the adhesion to an adherend, heat resistance, and the effect of suppressing whitening by moist heat. Among them, polyfunctional (meth) acrylates having an isocyanuric ring skeleton are preferably used.
The content of the crosslinking agent (2-B2) is not particularly limited. The ratio is 0.5 to 20 parts by mass, preferably 1 part by mass or more and 15 parts by mass or less, and preferably 2 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the (meth) acrylic copolymer (2-a 2).
By containing the crosslinking agent (2-B2) within the above range, the shape stability of the present adhesive sheet 2 in an uncrosslinked state and the reliability of the foaming resistance in the crosslinked adhesive sheet can be both satisfied. In addition, the balance with other elements may be out of the range.
(photopolymerization initiator (2-C2))
The photopolymerization initiator (2-C2) functions as a reaction initiation assistant in the crosslinking reaction of the crosslinking agent (2-B2), and the photopolymerization initiator (2-C1) described above can be suitably used.
The content of the photopolymerization initiator (2-C2) is not particularly limited. For reference, it is preferable that the content is 0.1 to 10 parts by mass, 0.5 part by mass or more or 5 parts by mass or less, or 1 part by mass or more or 3 parts by mass or less, based on 100 parts by mass of the (meth) acrylic copolymer (2-a 2).
By setting the content of the photopolymerization initiator (2-C2) to the above range, appropriate response sensitivity to active energy rays can be obtained.
(other Components)
The pressure-sensitive adhesive composition (2-II) may contain, as components other than those described above, known components usually blended in pressure-sensitive adhesive compositions. For example, various additives such as a tackifier resin, an antioxidant, a light stabilizer, a metal deactivator, an antiaging agent, a moisture absorbent, a polymerization inhibitor, an ultraviolet absorber, a rust inhibitor, a silane coupling agent, and inorganic particles may be suitably contained as required.
Further, if necessary, a reaction catalyst (tertiary amine compound, quaternary ammonium compound, tin laurate compound, etc.) may be suitably contained.
< method for producing adhesive sheet X >
Examples of the method for producing the adhesive sheet X include: a solution coating method of dissolving and coating the adhesive compositions (2-I) and (2-II) prepared by a known method in a solvent, a hot melt coating method of heating and melting the adhesive compositions and coating, and the like. The psa sheet is not particularly limited as long as the psa sheet of interest can be obtained, and can be produced by a known method.
When the pressure-sensitive adhesive compositions (2-I) and (2-II) are formed into a film product having a thickness of 50 μm or less, the solution coating method is preferably used from the viewpoint of easiness of thickness control. On the other hand, when a pressure-sensitive adhesive sheet having a thickness of 50 μm or more is formed, it is preferable to use a hot-melt coating method in view of environmental pollution and easiness of thick film formation.
< laminated Structure >
The present adhesive sheet 2 may be a sheet formed of a single layer, or may be a multilayer sheet formed by laminating 2 or more layers.
When the present adhesive sheet 2 is a multilayer transparent double-sided adhesive material, specific examples of the laminate structure include: 2 types of 2-layer structures obtained by laminating the present adhesive composition 2 and another adhesive resin composition, 2 types of 3-layer structures in which the present adhesive composition 2 is disposed on the front and back surfaces with an intermediate resin layer interposed therebetween, and 3 types of 3-layer structures in which the present adhesive composition 2, an intermediate resin composition, and another adhesive resin composition are laminated in this order. Among these, the outermost layer is preferably formed of the present adhesive composition 2, for example, the above adhesive compositions (2-I) and (2-II).
The present adhesive sheet 2 may be obtained by forming the present adhesive composition 2 and other adhesive resin compositions into a sheet on different release films or image display device constituting members, and laminating both adhesive surfaces, the present adhesive sheet 2 may be obtained by sequentially co-extruding the present adhesive composition 2, an intermediate resin composition, and an adhesive resin composition to obtain 2 types of 3-layer present adhesive sheets 2, and the present adhesive sheet 2 may be obtained by laminating the present adhesive composition 2 or other adhesive resin compositions on the front surface or the back surface of the intermediate resin layer.
For example, the pressure-sensitive adhesive sheet may be a substrate-attached pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from the present pressure-sensitive adhesive composition 2 (referred to as "present pressure-sensitive adhesive layer 2") on a substrate, or may be a substrate-free pressure-sensitive adhesive sheet having no substrate. Further, the double-sided pressure-sensitive adhesive sheet may be provided with the present adhesive layer 2 on both the upper and lower sides, or may be provided with the single-sided pressure-sensitive adhesive sheet with the present adhesive layer 2 only on one of the upper and lower sides.
< thickness >
From the viewpoint of preventing the thinning of the image display device, the thickness of the adhesive sheet 2 is preferably 250 μm or less at the maximum thickness portion. In other words, the present pressure-sensitive adhesive sheet 2 may be a sheet having a uniform thickness or a sheet having a locally different thickness, and when the sheet has a non-uniform thickness, the thickness of the portion having the largest thickness is preferably 250 μm or less.
From the viewpoint of not impairing the adhesion force to an adherend and the impact absorbability, the thickness of the maximum thickness portion is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more.
< use >
The present pressure-sensitive adhesive sheet 2 may be used in the original form or in the following manner. In addition, the method of using the adhesive sheet 2 is not limited.
(adhesive sheet laminate 2)
The present adhesive sheet 2 may be provided in the form of an adhesive sheet laminate 2 having a structure in which a release film is laminated on one or both sides of the present adhesive sheet 2, for example.
In this case, the present adhesive sheet 2 may have the soft portion and the hard portion on the sheet surface as shown in fig. 1 or 2, or may have the hard portion on at least one end surface of the adhesive sheet as shown in fig. 3 (a) and (B). In this case, the entire surface of the end surface portion may be the hard portion, or a part of the end surface portion may be the hard portion. In addition, the end face and the inner surface may have a hard portion.
As shown in fig. 4 (a) and (B), when the end surface portion of the present adhesive sheet 2 is in the form of a hard portion, the exposed end surface portion is not sticky even under extreme environments such as high temperature and high humidity, and thus can be suitably stored.
(laminate for constituting image display device 2)
When the present adhesive sheet 2 has the soft portion and the hard portion in the sheet surface, for example, a laminate for constituting an image display device having a structure in which the present adhesive sheet 2 is laminated between 2 constituent members for an image display device (hereinafter referred to as "laminate 2 for constituting an image display device") can be produced and provided.
The laminate 2 for constituting an image display device can be produced, for example, as follows: an image display device constituting member having a light-impermeable portion and a light-permeable portion on a bonding surface and another image display device constituting member are laminated with the adhesive sheet X therebetween, and the adhesive sheet X is irradiated with light through the former image display device constituting member to partially photocure the adhesive sheet.
Examples of the laminate 2 for constituting the image display device include: examples of the laminate including the protective panel/the present adhesive sheet 2/the polarizing film include image display panel/the present adhesive sheet 2/touch panel, image display panel/the present adhesive sheet 2/protective panel, image display panel/the present adhesive sheet 2/touch panel/the present adhesive sheet 2/protective panel, polarizing film/the present adhesive sheet 2/touch panel/the present adhesive sheet 2/protective panel, and the like.
As for the protective panel and the image display panel, a touch panel sensor may be incorporated in the protective panel or the image display panel itself.
(present image display device 2)
An image display device (hereinafter referred to as "the present image display device 2") can be configured using the present adhesive sheet 2 or the above-described image display device configuration laminate.
That is, the present image display device 2 may be configured as an image display device: the image display device is provided with at least 2 image display device components which face each other, and at least one of the image display device components has a light-impermeable portion and a light-permeable portion on a bonding surface, and is characterized by having a structure in which the 2 image display device components are filled with an adhesive sheet, wherein the adhesive sheet has a gel fraction of 40% or more at a position in contact with the light-permeable portion, and a gel fraction of less than 1% at a position in contact with the light-impermeable portion.
In the laminate 2 for constituting an image display device and the image display device 2, when a constituent member for an image display device having a portion which does not transmit light of a wavelength necessary for photocuring (referred to as "opaque portion" in the present invention) such as a printed portion around a screen and a portion which transmits light of a wavelength necessary for photocuring (referred to as "transparent portion" in the present invention) is bonded to another constituent member for an image display device, stress applied by being pressed by the opaque portion can be relaxed by setting the gel fraction of a portion in contact with the opaque portion to less than 1% and setting the gel fraction of a portion in contact with the transparent portion to 40% or more, and adherends can be firmly bonded to each other with high cohesive force while reducing strain generated in the portion.
The gel fraction at the position in contact with the opaque portion is particularly preferably less than 1%, and more preferably less than 0.8%.
On the other hand, the gel fraction at the position in contact with the light-transmitting portion is particularly preferably 40% or more, and more preferably 45% or more.
An example of a preferable manufacturing method of the image display device 2 will be described.
First, the adhesive sheet X is heated and melted, and the image display device component 1 having the printing portion (1) and the image display device component 3 are laminated with the adhesive sheet X therebetween. At this stage, the pressure-sensitive adhesive sheet X is appropriately flexible, and therefore can sufficiently follow the level difference while maintaining storage stability.
Next, light such as ultraviolet light is irradiated from the outside of the image display device constituting member 1. Thus, the printing portion (1) shields light, so that the light does not reach a portion in contact with the printing portion (1) or the reaching light is significantly limited, while the light sufficiently reaches a portion in contact with the light transmitting portion (3) not provided with the printing portion (1), and the crosslinking reaction of the portion can proceed to photocure, whereby excellent peeling resistance and foaming resistance can be achieved.
Examples of the 2 image display device components include: a computer, a mobile terminal (PDA), a game machine, a Television (TV), a car navigation system, a touch panel, a tablet, or the like, and an image display device such as an LCD, a PDP, or an EL. More specifically, examples thereof include: a touch panel, an image display panel, a surface protection panel, and a polarizing film, or a laminate formed by combining two or more of them.
(adhesive sheet roll)
The present adhesive sheet 2 may be in a form of being wound into a roll as shown in fig. 5. For example, the adhesive sheet X may be produced by winding up the adhesive sheet X in a roll and then irradiating only the end face with light to cure the adhesive sheet X by light, or the adhesive sheet 2 having only the end face subjected to light curing may be produced by winding up the adhesive sheet X in a roll. In any case, if the end face of the pressure-sensitive adhesive sheet wound in a roll form is a photocurable part, the exposed end face of the roll does not become sticky even under extreme environments such as high temperature and high humidity, and thus can be suitably stored.
< present pressure-sensitive adhesive sheet 3>
A double-sided adhesive sheet (hereinafter referred to as "present adhesive sheet 3") which is another example of an embodiment of the present invention is a double-sided adhesive sheet formed from an adhesive resin composition (hereinafter referred to as "present adhesive resin composition 3") containing 100 parts by mass of a (meth) acrylic copolymer (3-A), 0.5 to 20 parts by mass of a crosslinking agent (3-B), and 0.1 to 5 parts by mass of a photopolymerization initiator (3-C), and is characterized in that the tensile modulus (X) before photocrosslinking is the tensile modulus 1 ) Tensile modulus (X) after photocrosslinking 2 ) Ratio of (X) 1 /X 2 ) Is 3 or more.
In the field of image display devices such as mobile phones and mobile terminals, design diversification is progressing in addition to thinning and high precision, and new problems are also occurring. For example, a frame-shaped black shielding portion is usually printed on the peripheral edge portion of the surface protection panel. Therefore, the pressure-sensitive adhesive sheet for bonding a component member having such a printing portion is required to have a print step following property capable of following the print step and filling the corners. In this case, when the tackiness (tackiness) before photocrosslinking is absent, the bonding operation is not easy.
Accordingly, the present invention provides a photo-crosslinkable pressure-sensitive adhesive sheet 3 which has adhesiveness even before photo-crosslinking, does not cause overflow or collapse of the pressure-sensitive adhesive resin composition due to excessive flow of the pressure-sensitive adhesive material during bonding, and can obtain sufficient hardness after photo-crosslinking.
The adhesive sheet 3 has a tensile modulus (X) before and after photocrosslinking 1 ) The adhesive composition has a remarkably large difference in the degree of adhesion even before photocrosslinking, and the adhesive resin composition does not flow excessively during bonding and thus does not overflow or collapse, and further sufficient hardness can be obtained after photocrosslinking.
< present adhesive resin composition 3>
As described above, the adhesive resin composition 3 is a resin composition containing the (meth) acrylic copolymer (3-A), the crosslinking agent (3-B), and the photopolymerization initiator (3-C).
< (meth) acrylic copolymer (3-A) >
The (meth) acrylic copolymer (3-A) as the base polymer is preferably a graft copolymer (3-A1) having a macromonomer as a branch component.
Here, the "base polymer" refers to a resin constituting the main component of the present adhesive resin composition 3. The specific content of the base polymer is not limited, and is, as a standard, 50 mass% or more, 80 mass% or more, and 90 mass% or more (including 100 mass%) of the resin contained in the present adhesive resin composition 3. In the case where the base polymer is two or more, the total amount thereof corresponds to the above content.
(Main component)
The stem component of the graft copolymer (3-A1) is preferably composed of a copolymer component containing a repeating unit derived from a (meth) acrylate ester.
The glass transition temperature of the copolymer constituting the main component of the graft copolymer (3-A1) is preferably-70 to 0 ℃.
In this case, the glass transition temperature of the copolymer component constituting the main component means the glass transition temperature of a polymer obtained by copolymerizing only the monomer component constituting the main component of the graft copolymer (3-a 1). Specifically, the value is calculated by the Fox equation based on the glass transition temperature and the composition ratio of the polymer obtained from the homopolymer of each component of the copolymer.
The Fox equation is a calculated value obtained by the following formula, and can be obtained by using a value described in a polymer handbook [ polymer handbook, j.
1/(273+Tg)＝Σ(Wi/(273+Tgi))
[ in the formula, Wi represents the weight percent of the monomer i, and Tgi represents the Tg (. degree. C.) of the homopolymer of the monomer i. ]
Since the glass transition temperature of the copolymer component constituting the main component of the graft copolymer (3-a1) affects the flexibility of the present adhesive resin composition 3 in a room temperature state and the wettability, i.e., the adhesiveness of the present adhesive resin composition 3 to an adherend, the glass transition temperature is preferably-70 ℃ to 0 ℃, more preferably-65 ℃ or-5 ℃ or less, particularly preferably-60 ℃ or more or-10 ℃ or less, in order to obtain a proper adhesiveness (viscosity) of the present adhesive resin composition 3 in a room temperature state.
Even when the glass transition temperature of the copolymer component is the same temperature, the viscoelasticity can be adjusted by adjusting the molecular weight. For example, by reducing the molecular weight of the copolymer component, it can be made softer.
Examples of the (meth) acrylate monomer contained in the backbone component of the graft copolymer (3-a1) include: 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, n-butyl acrylate, ethyl acrylate, methyl methacrylate, methyl acrylate, and the like. Among them, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, glycidyl acrylate, acrylamide, N-dimethylacrylamide, acrylonitrile, methacrylonitrile, and the like having a hydrophilic group, an organic functional group, and the like can be used.
In addition, various vinyl monomers such as vinyl acetate, alkyl vinyl ether, and hydroxyalkyl vinyl ether copolymerizable with the above acrylic monomer and methacrylic monomer can also be suitably used.
The stem component of the graft copolymer (3-a1) preferably contains a hydrophobic (meth) acrylate monomer and a hydrophilic (meth) acrylate monomer as constituent units.
Since the main component of the graft copolymer (3-a1) is composed of only a hydrophobic monomer, the main component tends to be whitened by moist heat, it is preferable to introduce a hydrophilic monomer into the main component to prevent whitening by moist heat.
Specifically, the main component of the graft copolymer (3-a1) includes a copolymer component obtained by random copolymerization of a hydrophobic (meth) acrylate monomer, a hydrophilic (meth) acrylate monomer, and a polymerizable functional group at the end of a macromonomer.
Here, the hydrophobic (meth) acrylate monomer is preferably an alkyl ester having no polar group (excluding methyl acrylate), and examples thereof include: n-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, n-decyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-methylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isodecyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, methyl methacrylate, vinyl acetate, and the like.
The hydrophilic (meth) acrylate monomer is preferably methyl acrylate or an ester having a polar group, and examples thereof include: methyl acrylate, (meth) acrylic acid, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, N-dimethylacrylamide, hydroxyethylacrylamide, and the like.
(Branch component: macromonomer)
As the graft component of the graft copolymer (3-A1), it is preferable to introduce a macromonomer containing a repeating unit derived from the macromonomer.
The macromonomer is a high molecular monomer having a polymerizable functional group at the end and a high molecular weight skeleton component.
The glass transition temperature (Tg) of the macromonomer is preferably higher than the glass transition temperature of the copolymer component constituting the above graft copolymer (3-A1).
Specifically, the glass transition temperature (Tg) of the macromonomer affects the heating melting temperature (hot melt temperature) of the present adhesive resin composition 3, and the glass transition temperature (Tg) of the macromonomer is preferably 30 ℃ to 120 ℃, of these, 40 ℃ or more or 110 ℃ or less is preferable, and 50 ℃ or more or 100 ℃ or less is further preferable.
When the glass transition temperature (Tg) is set as described above, excellent processability and storage stability can be maintained by adjusting the molecular weight, and the temperature can be adjusted to be hot-melted at around 80 ℃.
The glass transition temperature of the macromonomer is the glass transition temperature of the macromonomer itself and can be measured by a Differential Scanning Calorimeter (DSC). (temperature rising Rate: 5 ℃ C./minute, Tg was measured from the inflection point of the base line shift)
Further, it is also preferable to adjust the molecular weight and content of the macromonomer because the branched components are adsorbed to each other at room temperature, the present binder resin composition 3 can maintain a physically crosslinked state, and the physical crosslinking can be released to obtain fluidity by heating to an appropriate temperature.
From the above-mentioned viewpoint, the macromonomer is preferably contained in the graft copolymer (3-a1) at a ratio of 5 to 30% by mass, of which 6% by mass or more or 25% by mass or less is preferable, and 8% by mass or more or 20% by mass or less is preferable.
In addition, the number average molecular weight of the macromonomer is preferably 500 or more and less than 8000, among them preferably 800 or more or less than 7500, among them preferably 1000 or more or less than 7000.
As the macromonomer, conventionally produced one (for example, macromonomer produced by Toyo Synthesis Co., Ltd.) can be used.
The high molecular weight backbone component of the macromonomer is preferably an acrylic polymer or a vinyl polymer.
Examples of the high molecular weight skeleton component of the macromonomer include: polystyrene, copolymers of styrene and acrylonitrile, poly (t-butylstyrene), poly (α -methylstyrene), polyvinyltoluene, polymethyl methacrylate, and the like.
Examples of the terminal polymerizable functional group of the macromonomer include a methacryloyl group, an acryloyl group, and a vinyl group.
Physical Properties of (meth) acrylic copolymer (3-A)
The complex viscosity of the (meth) acrylic copolymer (3-A) at a temperature of 130 ℃ and a frequency of 0.02Hz is preferably 100 to 800 pas, more preferably 150 to 700 pas, and still more preferably 170 to 600 pas.
Since the complex viscosity of the (meth) acrylic copolymer (3-A) at 130 ℃ affects the fluidity of the adhesive resin composition when the transparent double-sided adhesive material is used by hot-melting, the complex viscosity is 100 to 800 pas, which can provide excellent hot-melt suitability.
In order to adjust the complex viscosity of the (meth) acrylic copolymer (3-A) to the above range, for example, the glass transition temperature of the copolymer component constituting the main component of the graft copolymer (3-A1) may be adjusted. A preferable method is a method of adjusting the viscoelasticity by adjusting the molecular weight of the copolymer component to-70 ℃ to 0 ℃, particularly-65 ℃ or higher or-5 ℃ or lower, particularly-60 ℃ or higher or-10 ℃ or lower. In addition, the method is not limited thereto.
< crosslinking agent (3-B) >
As the crosslinking agent (3-B), for example, a crosslinking agent having 2 or more crosslinkable groups such as an epoxy group, an isocyanate group, an oxetanyl group, a silanol group, and a (meth) acryloyl group can be suitably selected. Among them, polyfunctional (meth) acrylates having 2 or more (meth) acryloyl groups, preferably 3 or more (meth) acryloyl groups among them, and (meth) acrylates having epoxy groups, isocyanate groups, and silanol groups are preferable in terms of reactivity and strength of the resulting cured product.
Examples of such a polyfunctional (meth) acrylate include: 1, 4-butanediol di (meth) acrylate, glycerol glycidyl ether di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, bisphenol A polypropoxy di (meth) acrylate, bisphenol F polyethoxy di (meth) acrylate, ethylene glycol di (meth) acrylate, trimethylolpropane triethoxy ethyl (meth) acrylate, epsilon-caprolactone-modified tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, ethylene glycol di (meth) acrylate, ethylene glycol, Pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyethylene glycol di (meth) acrylate, tris (acryloyloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ultraviolet-curable polyfunctional monomers such as dipentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, di (meth) acrylate of an epsilon-caprolactone adduct of hydroxypivalic acid neopentyl glycol, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxy tri (meth) acrylate, and ditrimethylolpropane tetra (meth) acrylate; and polyfunctional acrylic oligomers such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyether (meth) acrylate, isocyanate (meth) acrylate, 1- (bis (meth) acryloyloxymethyl) ethyl isocyanate, 2- (2- (meth) acryloyloxyethyloxy) ethyl isocyanate, glycidyl (meth) acrylate, hydroxyethyl acrylate glycidyl ether, hydroxypropyl (meth) acrylate glycidyl ether, and hydroxybutyl (meth) acrylate glycidyl ether.
Among the above, polyfunctional monomers or oligomers containing a polar functional group such as a hydroxyl group are preferable from the viewpoint of improving the adhesion to an adherend and suppressing the effect of whitening by moist heat.
Among them, polyfunctional (meth) acrylates having a hydroxyl group are preferably used.
Therefore, from the viewpoint of preventing moist heat whitening, it is preferable to contain a hydrophobic acrylate monomer and a hydrophilic acrylate monomer as the main component of the graft copolymer (3-a1), and further, it is preferable to use a hydroxyl group-containing polyfunctional (meth) acrylate as the crosslinking agent (3-B).
The content of the crosslinking agent (3-B) is preferably 0.5 to 20 parts by mass, more preferably 1 part by mass or more and 15 parts by mass or less, and still more preferably 2 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the (meth) acrylic copolymer (3-a).
By containing the crosslinking agent (3-B) within the above range, the shape stability of the present adhesive sheet 3 in an uncrosslinked state and the reliability of foaming resistance in the crosslinked adhesive material can be both satisfied. In addition, the balance with other elements may be out of the range.
< photopolymerization initiator (3-C) >
The photopolymerization initiator (3-C) functions as a reaction initiation aid in the crosslinking reaction of the crosslinking agent (3-B).
The photopolymerization initiator may be any of those known in the art. Among them, a photopolymerization initiator which is sensitive to ultraviolet rays having a wavelength of 380nm or less is preferable from the viewpoint of easiness of control of the crosslinking reaction.
On the other hand, light induced by a photopolymerization initiator which induces light having a wavelength longer than 380nm is preferable in that the light easily reaches the depth of the adhesive sheet 3.
Photopolymerization initiators are roughly classified into two types according to the mechanism of radical generation: a cleavage type photopolymerization initiator capable of generating radicals by breaking and decomposing a single bond of the photopolymerization initiator itself; and a hydrogen abstraction type photopolymerization initiator which forms an excited complex with a hydrogen donor in the system by the photo-excited initiator and can transfer hydrogen from the hydrogen donor.
Among these, the cleavage type photopolymerization initiators decompose to form other compounds when radicals are generated by irradiation with light, and once excited, lose their functions as reaction initiators. Therefore, the binder after the completion of the crosslinking reaction is not left as an active species in the binder, and there is no possibility that the binder is subjected to unexpected photo-deterioration or the like, so that it is preferable.
On the other hand, since the hydrogen abstraction-type photopolymerization initiator does not generate a decomposition product such as a cleavage-type photopolymerization initiator when radical generation reaction is caused by irradiation with active energy rays such as ultraviolet rays, it is not likely to become a volatile component after the reaction is completed, and is useful in that damage to an adherend can be reduced.
Examples of the cleavage type photoinitiator include: 2, 2-dimethoxy-1, 2-diphenylethan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- (4- (2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- [4- {4- (2-hydroxy-2-methyl-propionyl) benzyl } phenyl ] -2-methyl-propan-1-one, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone); poly (1-hydroxy-2-methyl-1-one, poly (2-hydroxy-2-methyl-1-propanone); poly (2-hydroxy-2-1-methyl-1-methyl-propanone); poly (1-hydroxy-2-methyl-1-propanone); poly (1-methyl-propanone); poly (1-hydroxy-1-methyl-propanone), Methyl phenylglyoxylate, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropan-1-one, 2- (dimethylamino) -2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholino) phenyl ] -1-butanone, bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, derivatives of these, and the like.
Examples of the hydrogen abstraction photoinitiator include: benzophenone, 4-methyl-benzophenone, 2,4, 6-trimethylbenzophenone, 4-phenylbenzophenone, 3' -dimethyl-4-methoxybenzophenone, 4- (meth) acryloyloxybenzophenone, methyl 2-benzoylbenzoate, methyl benzoylformate, bis (2-phenyl-2-oxoacetic acid) oxydiethylene, 4- (1, 3-acryloyl-1, 4,7,10, 13-pentaoxotridecyl) benzophenone, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2, 4-dimethylthioxanthone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, derivatives thereof, and the like.
The photopolymerization initiator is not limited to the above examples. Any one of the above-listed cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators may be used, or two or more thereof may be used in combination.
The content of the photopolymerization initiator (3-C) is preferably 0.1 to 5 parts by mass, more preferably 0.5 parts by mass or more or 3 parts by mass or less, and further preferably 1 part by mass or more, relative to 100 parts by mass of the (meth) acrylic copolymer (3-a).
When the content of the photopolymerization initiator (3-C) is in the above range, a suitable response sensitivity to active energy rays can be obtained.
< other ingredients >
The present adhesive resin composition 3 may contain, as components other than those described above, known components that can be generally blended in an adhesive resin composition. For example, various additives such as a tackifier resin, an antioxidant, a light stabilizer, a metal deactivator, an antioxidant, a moisture absorbent, a polymerization inhibitor, an ultraviolet absorber, a rust inhibitor, a silane coupling agent, and inorganic particles may be suitably contained as required.
Further, if necessary, a reaction catalyst (tertiary amine compound, quaternary ammonium compound, tin laurate compound, etc.) may be suitably contained.
< features of the adhesive sheet 3>
The present adhesive sheet 3 may be the following adhesive sheet: can be kept in a sheet form in a normal state, has a hot-melt property that melts or flows when heated in an uncrosslinked state, and has a photocurable property that enables photocuring.
When the sheet-like adhesive is held in a normal state, handling is easier than with a liquid adhesive, filling with a liquid can be omitted, and productivity is particularly excellent. In this case, in the case where the adhesive sheet has a proper adhesiveness in a normal state, that is, in the vicinity of room temperature, that is, a property of being able to adhere to an adherend by a slight force in a short time (referred to as "tackiness"), since positioning at the time of sticking is easy to be performed and workability is excellent, the adhesive sheet preferably has tackiness in a normal state, that is, in the vicinity of room temperature, and more preferably also has tackiness in a relatively low temperature region of-5 ℃ to 20 ℃. Such tackiness can be obtained by using the above graft copolymer (3-A1) as the (meth) acrylic copolymer (3-A).
In addition, in the case of hot melt which melts or flows when heated, the adhesive can be filled so as to follow up the uneven portions such as the printing step by softening or flowing the hot melt by heating, and therefore, the adhesive can be filled without causing foaming or the like.
Further, when photo-curable, the adhesive can be firmly bonded by final photo-curing.
As described above, in order to produce a pressure-sensitive adhesive sheet which can be held in a sheet form in a normal state, has a hot-melt property that melts or flows when heated in an uncrosslinked state, and can be photo-cured, for example, a single-layer pressure-sensitive adhesive sheet can be produced from the present pressure-sensitive adhesive resin composition 3. On the other hand, in the case of a multilayer adhesive sheet, for example, there are: 2 types of 2 layers in which a pressure-sensitive adhesive layer composed of the present pressure-sensitive adhesive resin composition 3 and a pressure-sensitive adhesive layer composed of another pressure-sensitive adhesive resin composition are laminated, 2 types of 3 layers in which pressure-sensitive adhesive layers composed of the present pressure-sensitive adhesive resin composition 3 are disposed on the front and back surfaces with an intermediate resin layer interposed therebetween, 3 types of 3 layers in which a pressure-sensitive adhesive layer composed of the present pressure-sensitive adhesive resin composition 3, an intermediate layer composed of the intermediate resin composition, and a pressure-sensitive adhesive layer composed of another pressure-sensitive adhesive resin composition are laminated in this order, and the like.
In addition, the adhesive resin composition used for forming the adhesive sheet 3 is not limited to the present adhesive resin composition 3.
(gel fraction)
From the viewpoint of exhibiting hot-melt properties in the state before photocuring, the gel fraction (a) of the present adhesive sheet 3 before photocuring is 5% or less, preferably 4% or less, and particularly preferably 2% or less.
In addition, the gel fraction (b) of the adhesive sheet 3 after photocuring is preferably 50% or more, more preferably 60% or more or 90% or less, and particularly preferably 65% or more or 80% or less, from the viewpoint of obtaining high cohesive strength after photocuring and obtaining reliability in foaming resistance under a wet heat environment.
In order to adjust the gel fraction (a) before photocuring and the gel fraction (b) after photocuring as described above, for example, a graft copolymer (a1) containing a macromonomer as a branch component is used as the (meth) acrylic copolymer (3-a), and the composition ratio of a crosslinking agent and a photopolymerization initiator, or the temperature and the light irradiation amount during processing, may be adjusted. In addition, the method is not limited to this.
(tensile modulus)
The present adhesive sheet 3 had a tensile modulus (X) before photocrosslinking 1 ) Tensile modulus (X) after photocrosslinking 2 ) Ratio of (X) 2 /X 1 ) When the amount is 3 or more, good level difference absorption property and foaming resistance reliability can be obtained.
From the above viewpoint, the tensile modulus (X) before photocrosslinking 1 ) Tensile modulus (X) after photocrosslinking 2 ) Ratio of (X) 2 /X 1 ) Preferably 3 or more, and among them, preferably 5 or moreOr 30 or less, more preferably 10 or more or 27 or less.
Tensile modulus (X) before photocrosslinking 1 ) Preferably 0.01MPa or more and 0.2MPa or less, and more preferably 0.05MPa or more or 0.1MPa or less.
On the other hand, tensile modulus (X) after photocrosslinking 2 ) Preferably 0.8MPa or more and 2.0MPa or less, and more preferably 1.0MPa or more or 1.8MPa or less.
(tensile maximum stress (Y))
The present adhesive sheet 3 had a tensile maximum stress (Y) before photocrosslinking 1 ) Tensile maximum stress (Y) after photocrosslinking 2 ) Ratio of (Y) 2 /Y 1 ) When the amount is 5 or more and 20 or less, good level difference absorption property and foaming resistance reliability can be obtained.
From the above viewpoint, the tensile maximum stress (Y) before photocrosslinking of the adhesive sheet 3 is 1 ) Tensile maximum stress (Y) after photocrosslinking 2 ) Ratio of (Y) 2 /Y 1 ) Preferably 5 or more and 20 or less, and more preferably 8 or more or 15 or less.
Tensile maximum stress (Y) before photocrosslinking 1 ) Preferably 0.5N or more and 5N or less, and particularly preferably 0.8N or more or 2N or less.
On the other hand, the tensile maximum stress (Y) after photocrosslinking 2 ) It is preferably 7N or more and 15N or less, and particularly preferably 9N or more or 12N or less.
(tensile breaking stress (Z))
The present adhesive sheet 3 had a tensile breaking stress (Z) before photocrosslinking 1 ) Tensile stress at break (Z) after photocrosslinking 2 ) Ratio of (Z) 2 /Z 1 ) When the amount is 10 or more and 50 or less, good level difference absorption property and foaming resistance reliability can be obtained.
From the above viewpoint, the tensile breaking stress (Z) before photocrosslinking of the adhesive sheet 3 1 ) Tensile stress at break (Z) after photocrosslinking 2 ) Ratio of (Z) 2 /Z 1 ) Preferably 10 or more and 50 or less, and particularly preferably 15 or more or 40 or less.
Tensile stress at break (Z) before photocrosslinking 1 ) Preferably 0.1N or more and 2N or less, and particularly preferably 0.2N or more or 0.6N or less.
On the other hand, tensile breaking stress (Z) after photocrosslinking 2 ) Preferably 7N or more and 16N or less, and particularly preferably 9N or more or 12N or less.
In the present pressure-sensitive adhesive sheet 3, in order to adjust the tensile modulus, the maximum tensile stress and the tensile breaking stress to the above ranges, for example, a graft copolymer (3-a1) having a macromonomer as a branch component may be used as the (meth) acrylic copolymer (3-a), and the type and the number of parts of the macromonomer may be adjusted. In addition, the method is not limited to this.
When the graft copolymer (3-a1) containing a macromonomer as a branch component is used as the (meth) acrylic copolymer (3-a), the sheet-like shape can be maintained even in a normal state, fluidity can be exhibited by heating to satisfy level difference following properties, and curing reaction can be performed by ultraviolet crosslinking to obtain excellent adhesion reliability.
< laminated Structure >
The present adhesive sheet 3 may be a sheet formed of a single layer, or may be a multilayer sheet formed by laminating 2 or more layers.
When the present adhesive sheet 3 is a multilayer transparent double-sided adhesive material, the outermost layer preferably has both unevenness follow-up property and foaming resistance reliability as in the case of the single layer, and therefore is preferably molded with the present adhesive resin composition 3.
On the other hand, the intermediate layer does not contribute to adhesion of the image display device constituent member, and therefore, preferably has light transmittance to such an extent that transparency is not impaired and 2-time curing reaction of the outermost layer is not inhibited, and has properties of improving cuttability and handleability.
The kind of the base polymer forming the intermediate layer is not particularly limited as long as it is a transparent resin. The base polymer forming the intermediate layer may be the same resin as the base polymer of the outermost layer or may be a different resin. Among them, from the viewpoint of ensuring transparency, facilitating production, and preventing refraction of light at the lamination interface, it is preferable to use the same acrylic resin as the base polymer of the outermost layer.
The intermediate layer and the other resin layer may or may not have active energy ray curability. For example, the curable composition may be formed so as to be cured by ultraviolet crosslinking, or may be formed so as to be cured by heat. In addition, the post-curing may be performed without particular limitation. In view of adhesion to the outermost layer, the resin composition is preferably formed by post-curing, and particularly preferably by ultraviolet crosslinking.
In this case, since the light transmittance decreases when the content of the crosslinking initiator is increased, it is preferable to contain the ultraviolet crosslinking agent in a content lower than the content of the crosslinking initiator in the outer layer in the intermediate layer.
When the present adhesive sheet 3 is a multilayer transparent double-sided adhesive material, specific examples of the laminate structure include: 2 types of 2-layer structures obtained by laminating the present adhesive resin composition 3 and another adhesive resin composition, 2 types of 3-layer structures in which the present adhesive resin composition 3 is disposed on the front and back surfaces with an intermediate resin layer interposed therebetween, and 3 types of 3-layer structures in which the present adhesive resin composition 3, an intermediate resin composition, and another adhesive resin composition are laminated in this order.
The present adhesive sheet 3 can be obtained by forming the present adhesive resin composition 3 and other adhesive resin compositions into a sheet form on different release films or image display device constituting members, and laminating both adhesive surfaces; further, the present adhesive resin composition 3, the intermediate resin composition and the adhesive resin composition may be coextruded in order to obtain 2 types of the present adhesive sheet 3 having 3 layers; the adhesive sheet 3 may be obtained by laminating the adhesive resin composition 3 or another adhesive resin composition on the front and back surfaces of the intermediate resin layer.
For example, the present adhesive layer 3 may be formed on a substrate to form a substrate-attached adhesive sheet, or may be a substrate-free adhesive sheet having no substrate. Further, the double-sided pressure-sensitive adhesive sheet may have the present pressure-sensitive adhesive layer 3 on both the upper and lower sides, or may have the present pressure-sensitive adhesive layer 3 only on one of the upper and lower sides.
< thickness >
The thickness of the adhesive sheet 3, i.e., the total thickness, is preferably 50 μm to 1mm, more preferably 75 μm or more, or 500 μm or less, from the viewpoint of not hindering the thinning of the image display device and from the viewpoint of the step absorption.
When the total thickness of the adhesive sheet 3 is 50 μm or more, it can follow irregularities such as high printing step, and when it is 1mm or less, it can satisfy the demand for thinning.
Further, the total thickness of the adhesive sheet 3 is preferably 75 μm or more, and more preferably 100 μm or more, from the viewpoint that the printing height of the shielding layer at the peripheral edge is higher than that in the conventional image display device, specifically, the step of about 80 μm can be filled. On the other hand, from the viewpoint of satisfying the demand for thinning, it is preferably 500 μm or less, and particularly preferably 350 μm or less.
From the viewpoint of not impairing the adhesion force to an adherend and the impact absorbability, the thickness of the maximum thickness portion is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more.
In the case of a multilayer structure, the ratio of the thickness of each outermost layer to the thickness of the intermediate layer is 1: 1-1: 20, particularly preferably 1: 2-1: 10.
when the thickness of the intermediate layer is within the above range, the contribution of the thickness of the adhesive material layer in the laminate is not excessive, and the intermediate layer is not excessively flexible, so that the workability in cutting and handling is not deteriorated.
In addition, when the outermost layer is in the above range, the adhesion to an adherend and the wettability can be maintained without deteriorating the conformability to uneven and curved surfaces, which is preferable.
The thickness of the maximum thickness portion of the adhesive sheet 3 is preferably 250 μm or less. In other words, the present pressure-sensitive adhesive sheet 3 may be a sheet having a uniform thickness or a sheet having a locally different thickness, and when the sheet has a non-uniform thickness, the thickness of the portion having the largest thickness is preferably 250 μm or less.
< use >
The present adhesive sheet 3 may be used as it is, or may be used as follows. In addition, the method of using the adhesive sheet 3 is not limited.
(adhesive sheet laminate)
The present adhesive sheet 3 may be provided as, for example, an adhesive sheet laminate having a structure in which a release film is laminated on one surface or both surfaces of the present adhesive sheet 3.
(laminate for constituting image display device 3)
As an example of the application of the present adhesive sheet 3, a laminate for constituting an image display device (hereinafter referred to as "laminate for constituting an image display device 3") having a structure in which the present adhesive sheet 3 is laminated between 2 constituent members for an image display device can be produced.
The laminate 3 for constituting an image display device includes, for example, the following laminates for constituting an image display device: the adhesive sheet is provided with a laminate for image display device construction, which comprises at least 2 facing image display device constituent members, at least one of which has a light-impermeable portion and a light-permeable portion on a bonding surface, and the adhesive sheet 3 is filled between the 2 image display device constituent members, wherein the adhesive sheet is partially photocured by irradiating the adhesive sheet with light through the image display device constituent members.
In this case, the adhesive sheet may have a gel fraction of 50% or more at a position in contact with the light-transmitting portion and a gel fraction of less than 5% at a position in contact with the non-light-transmitting portion.
Here, the constituent member for an image display device may be any one of a group consisting of a touch panel, an image display panel, a surface protection panel, and a polarizing film, or a laminate formed by combining two or more of them.
Examples of the laminate 3 for constituting the image display device include: examples of the laminate having the protective panel/adhesive sheet 3/polarizing film structure include image display panel/adhesive sheet 3/touch panel, image display panel/adhesive sheet 3/protective panel, image display panel/adhesive sheet 3/touch panel/adhesive sheet 3/protective panel, polarizing film/adhesive sheet 3/touch panel/adhesive sheet 3/protective panel, and the like.
As for the protective panel and the image display panel, a touch panel sensor may be incorporated in the protective panel or the image display panel itself.
The laminate 3 for constituting the image display device can be produced through, for example, the following steps (1) to (3).
Further, the method of manufacturing the laminate 3 for constituting an image display device of the present invention may include at least the following steps (1) to (3), and thus, other steps may be added or inserted between the steps.
Step (1) a pressure-sensitive adhesive resin composition containing a (meth) acrylic copolymer (3-a), a crosslinking agent (B), and a photopolymerization initiator (C) is prepared, and the pressure-sensitive adhesive resin composition is molded into a single-layer or multi-layer sheet to produce the pressure-sensitive adhesive sheet 3.
Step (2) is to laminate 2 image display device components by attaching them with the present adhesive sheet 3 interposed therebetween.
Step (3) irradiates the adhesive sheet 3 with active energy rays from the outside of at least one of the image display device constituent members to crosslink the adhesive sheet 3, thereby bonding 2 image display device constituent members.
(step (1))
In the step (1), the adhesive resin composition 3 is prepared by a known method, and a single-layer or multi-layer sheet-like material having an adhesive layer formed of the adhesive resin composition in an uncrosslinked state is formed to produce the adhesive sheet 3.
The method for forming the binder resin composition 3 into a sheet can be any conventionally known method.
In this case, the present adhesive resin composition 3 may be formed into a single-layer or multi-layer sheet on a release film to produce a single-layer or multi-layer transparent double-sided pressure-sensitive adhesive material having a pressure-sensitive adhesive layer.
The adhesive resin composition 3 may be formed into a single-layer or multi-layer sheet on an image display device-constituting member to produce a single-layer or multi-layer transparent double-sided adhesive material having an adhesive layer on the image display device-constituting member.
(step (2))
In the step (2), 2 image display device constituting members may be attached to sandwich the present adhesive sheet 3 and laminated.
In this case, when the graft copolymer (a1) is used as the base polymer of the present adhesive sheet 3, the macromonomers are polymerized in and form a physical crosslinked structure at room temperature, which is a normal state, and thus the present adhesive sheet 3 can be provided with excellent storage stability and cutting processability.
The (meth) acrylic copolymer (3-A) has a complex viscosity of 100 to 800 pas at a temperature of 130 ℃ and a frequency of 0.02Hz, and can be used as a hot-melt sheet for bonding, thereby having excellent handling properties.
In this way, in the step (2), 2 image display device constituting members can be attached and laminated with the present adhesive sheet 3 interposed therebetween. In this way, since the pressure-sensitive adhesive sheet 3 can be simply adhered to an adherend by merely pressing the sheet, positioning of the adhesive material can be easily performed, and the operation is very convenient.
In addition, the adhesive sheet 3 may be cut in advance from the release film, which is formed on the release film, in accordance with the size of the image display device constituent member to be laminated, because the adhesive sheet 3 has excellent shape retention and can be processed into an arbitrary shape in advance.
In the cutting method, punching with a thomson cutter, cutting with a super cutter (super cutter), or a laser is generally used, and it is more preferable that the mold release film on either the front surface or the back surface is half-cut so that the mold release film is easily peeled off, and the cut film is left in a frame shape.
In the step (2), the present adhesive sheet 3, i.e., the transparent double-sided adhesive material is also in an uncrosslinked state.
(step (3))
In the step (3), the adhesive layer of the adhesive sheet 3 is irradiated with active energy rays from the outside of at least one of the image display device constituting members to crosslink the adhesive layer, and 2 image display device constituting members are bonded to each other, whereby the laminate 3 for constituting an image display device can be produced.
Since the adhesive sheet 3 contains the crosslinking agent (B) and the photopolymerization initiator (C), the adhesive layer of the adhesive sheet 3 can be crosslinked and cured by irradiating the adhesive layer with active energy rays, and 2 image display device constituting members can be firmly attached.
In this case, the active energy ray may be an energy ray which triggers the polymerization initiator, such as a heat ray, an X-ray, an electron beam, an ultraviolet ray, or a visible light. Among them, from the viewpoint of suppressing damage to the image display device constituent member and the ease of reaction control, it is preferable to irradiate with ultraviolet rays, particularly ultraviolet rays having a wavelength of 380nm or less.
The ultraviolet irradiation conditions are not particularly limited. For example, the cumulative amount of ultraviolet light reaching the adhesive material is preferably 500 to 5000mJ/cm at a wavelength of 365nm 2 The irradiation is performed in the manner of (1). This is from the viewpoint of maintaining workability and sufficiently advancing the crosslinking reaction.
When the image display device constituting member interposed upon irradiation with ultraviolet rays shields light having the above-mentioned wavelength, it is preferable to appropriately adjust the type of energy ray absorbed by the adhesive material depending on the type of the polymerization initiator in accordance with the interposed member.
(other steps)
A step of heating the laminate obtained in the step (2) to heat and melt the adhesive layer of the transparent double-sided adhesive material may be interposed between the step (2) and the step (3). That is, the laminate attached in the step (2) may be heated to heat-melt (fuse) the adhesive layer of the present adhesive sheet 3.
The present adhesive sheet 3 can exhibit high fluidity by releasing the physical crosslinked structure by releasing the cohesion between the macromonomers upon heating. Therefore, when 2 image display device constituting members are laminated on the pressure-sensitive adhesive surface having irregularities such as printed step differences, the present pressure-sensitive adhesive sheet 3 is heated and fluidized (hot-melt), whereby the adhesive material has improved irregularity following properties and wettability to an adherend, and the members can be integrated more firmly without leaving any strain.
In this case, the composition is preferably heated to 60 to 100 ℃ to be thermally melted. When the temperature is 60 ℃ or higher, fluidity of the binder can be sufficiently imparted, and the uneven portions can be sufficiently filled with the binder resin composition. On the other hand, when the temperature is 100 ℃ or lower, not only can thermal damage to an image display device constituting member as an adherend be suppressed, but also occurrence of overflow or collapse of the pressure-sensitive adhesive resin composition due to excessive flow of the pressure-sensitive adhesive material can be prevented.
From such a viewpoint, the hot-melt temperature is preferably 60 to 100 ℃, more preferably 62 ℃ or more or 95 ℃ or less, and further preferably 65 ℃ or more or 90 ℃ or less.
(present image display device 3)
An image display device (hereinafter referred to as "the present image display device 3") can be configured using the present adhesive sheet 3 or the above-described image display device configuration laminate.
Examples thereof include: the present image display apparatus 3 is an image display apparatus including at least 2 facing image display apparatus components, at least one of the image display apparatus components having a non-light-transmissive portion and a light-transmissive portion on a bonding surface, and includes a configuration in which adhesive sheets are filled between the 2 image display apparatus components. In this case, the adhesive sheet may have a gel fraction of 50% or more at a position in contact with the light-transmitting portion and a gel fraction of less than 5% at a position in contact with the non-light-transmitting portion.
In the laminate 3 for constituting an image display device and the image display device 3, a constituent member for an image display device having a portion which does not transmit light of a wavelength necessary for photocuring (referred to as an "opaque portion" in the present invention) such as a printed portion around a screen and a portion which transmits light of a wavelength necessary for photocuring (referred to as a "transparent portion" in the present invention) is bonded to another constituent member for an image display device, and by setting the gel fraction at a position in contact with the opaque portion to less than 1% and setting the gel fraction at a position in contact with the transparent portion to 40% or more, stress applied by being pressed by the opaque portion can be relaxed, strain generated at the portion can be reduced, and adherends can be firmly bonded to each other with high cohesive force.
An example of a preferable manufacturing method of the image display device 3 will be described.
First, the present adhesive sheet 3 is heated and thermally melted, and the image display device component having the opaque portion as the printed portion and the image display device component are laminated with the present adhesive sheet 3 interposed therebetween. At this stage, the present adhesive sheet 3 is moderately flexible, and therefore can sufficiently follow the level difference while maintaining storage stability.
Next, light such as ultraviolet light is irradiated from the outside of the image display device constituent member. In this way, since the printed portion blocks light, the light does not reach the portion in contact with the printed portion, or the light reached is significantly limited, while the light sufficiently reaches the portion in contact with the light-transmitting portion where the printed portion is not present, and the crosslinking reaction at this portion can proceed to photocure the light, and excellent peeling resistance and foaming resistance can be achieved.
Examples of the 2 image display device components include: a computer, a mobile terminal (PDA), a game machine, a Television (TV), a car navigation system, a touch panel, a tablet, or the like, and an image display device such as an LCD, a PDP, or an EL. More specifically, examples thereof include: a laminate formed of any one of the group consisting of a touch panel, an image display panel, a surface protection panel, and a polarizing film, or a combination of two or more of them.
[ explanations of words and sentences, etc. ]
The general "sheet" means a thin flat product having a relatively small thickness with respect to the length and width in the definition of JIS; a general "film" refers to a thin and flat product having a thickness extremely small compared to the length and width and having a maximum thickness arbitrarily defined, and is usually supplied in the form of a roll (japanese industrial standard JIS K6900). However, since the boundary between the sheet and the film is not fixed, and it is not necessary to distinguish the two in the present invention in terms of letters, the case of "film" in the present invention also includes "sheet" and the case of "sheet" also includes "film".
In addition, the case of being expressed as a "panel" as in an image display panel, a protection panel, or the like includes a plate shape, a sheet, a film, or a laminate of these.
In the present specification, the description of "X to Y" (X, Y is an arbitrary number) includes, without particular limitation, the meaning of "X or more and Y or less" and also includes the meaning of "preferably more than X" or "preferably less than Y".
The term "X" or more (X is an arbitrary number) includes the meaning of "preferably more than X" without any particular limitation, the term "Y" or less (Y is an arbitrary number), and the meaning of "preferably less than Y" without any particular limitation.
Examples
Hereinafter, the details will be described in further detail with reference to examples. In addition, the present invention is not limited to these.
[ example 1-1]
1kg of an acrylic copolymer (1-A-1) (weight-average molecular weight: 23 ten thousand) obtained by random copolymerization of 15 parts by mass (18 mol%) of a polymethyl methacrylate macromonomer (Tg: 105 ℃) having a number-average molecular weight of 2400, 81 parts by mass (75 mol%) of butyl acrylate (Tg: -55 ℃) and 4 parts by mass (7 mol%) of acrylic acid (Tg: 106 ℃) as a (meth) acrylic copolymer (1-A), 75g of glycerol dimethacrylate (manufactured by Nichikoku Co., Ltd., product name: GMR) (1-B-1) as a crosslinking agent (1-B), and 15g of a mixture (manufactured by LAMBI GROUP, product name: ESACURE TZT) (1-C-1) of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone as a photopolymerization initiator (1-C) were uniformly mixed, adhesive composition 1-1 was prepared.
The composition 1-1 was sandwiched between two release films, i.e., two polyethylene terephthalate films (DIAFOIL MRV-V06 manufactured by Mitsubishi resin corporation, "DIAFOIL MRQ" manufactured by Mitsubishi resin corporation, thickness 100 μm/DIAFOIL MRQ manufactured by Mitsubishi resin corporation, thickness 75 μm), and the composition was shaped into a sheet form so as to have a thickness of 150 μm using a laminator, thereby producing an adhesive sheet 1-1 (thickness 150 μm).
A glass plate with a printing step having a non-printing portion of 198mm X148 mm was prepared by printing a glass plate having a peripheral portion (20 mm on the long side and 17mm on the short side) of 238mm X182 mm X0.8 mm thick and not transmitting ultraviolet light and having a thickness of 60 μm.
One release film of the pressure-sensitive adhesive sheet 1-1 was peeled off, and the sheet was roll-bonded to soda-lime glass 150mm × 200mm thick and 1mm thick.
Then, the remaining release film was peeled off, and after the printed surface of the glass plate with the printed step was pressed and bonded by a vacuum press so that 4 sides of the adhesive surface were laid on the printed step (absolute pressure 5kPa, temperature 80 ℃, pressing pressure 0.04MPa), autoclave treatment (80 ℃, gauge pressure 0.2MPa, 20 minutes) was performed to complete the attachment. Ultraviolet rays having a wavelength of 365nm reaching the adhesive sheet 1-1 from the glass side on which printing was performed were 2000mJ/cm 2 The adhesive sheet 1-1 was cured by irradiation with ultraviolet light using a high-pressure mercury lamp, thereby producing a laminate 1-1.
[ examples 1-2]
1kg of an acrylic copolymer (1-A-2) (weight-average molecular weight: 17 ten thousand) obtained by random copolymerization of 55 parts by mass (36 mol%) of 2-ethylhexyl acrylate (Tg: -70 ℃) and 40 parts by mass (56 mol%) of vinyl acetate (Tg: 32 ℃) and 5 parts by mass (8 mol%) of acrylic acid (Tg: 106 ℃), which are a (meth) acrylic copolymer (1-A), epsilon caprolactone-modified isocyanuric acid triacrylate (1-B-2) (product name: A9300-1CL, manufactured by Newzhou chemical Co., Ltd.) as a crosslinking agent (1-B) and 5g of ESACURE KTO46(1-C-2) (manufactured by LAMBERTI GROUP) as a photopolymerization initiator (1-C) were uniformly mixed to prepare adhesive compositions 1-2.
The composition 1-2 was shaped into a sheet form in the same manner as in example 1-1 to prepare a pressure-sensitive adhesive sheet 1-2 (thickness: 150 μm).
A laminate 1-2 was produced in the same manner as in example 1-1, except that the pressure-sensitive adhesive sheet 1-2 was used.
[ examples 1 to 3]
An acrylic copolymer (1-A-3) (weight-average molecular weight: 23 ten thousand) 1kg obtained by random copolymerization of 10 parts by mass (17 mol%) of a polymethyl methacrylate macromonomer (Tg: 105 ℃) having a number-average molecular weight of 1400 and 90 parts by mass (83 mol%) of 2-ethylhexyl acrylate (Tg: -70 ℃) as a (meth) acrylic copolymer (1-A), 50g of propoxylated pentaerythritol triacrylate (product name: ATM-4PL) (1-B-3) as a crosslinking agent (1-B) and 15g of 4-methylbenzophenone (1-C-3) as a photopolymerization initiator (1-C) were uniformly mixed to prepare an adhesive composition 1-3.
The composition 1-3 was shaped into a sheet form in the same manner as in example 1-1 to prepare a pressure-sensitive adhesive sheet 1-3 (thickness: 150 μm).
A laminate 1-3 was produced in the same manner as in example 1-1, except that the pressure-sensitive adhesive sheet 1-3 was used.
[ examples 1 to 4]
1kg of an acrylic copolymer (1-A-4) (weight-average molecular weight: 8 ten thousand) obtained by random copolymerization of 12 parts by mass (19 mol%) of a polymethyl methacrylate macromonomer (Tg: 105 ℃) having a number-average molecular weight of 2400, and 85 parts by mass (74 mol%) of 2-ethylhexyl acrylate (Tg: -70 ℃) and 3 parts by mass (7 mol%) of acrylic acid (Tg: 106 ℃), as the crosslinking agent (1-B), 90g of glycerol dimethacrylate (product name: GMR manufactured by Nichisu oil Co., Ltd.) (1-B-1) and 5g of ESACURE KTO46(1-C-2) (manufactured by LAMBERTI GROUP) as a photopolymerization initiator (1-C) were uniformly mixed to prepare adhesive compositions 1 to 4.
The above-mentioned composition 1-4 was shaped into a sheet in the same manner as in example 1-1 to prepare a pressure-sensitive adhesive sheet 1-4 (thickness: 150 μm).
A laminate 1-4 was produced in the same manner as in example 1-1, except that the pressure-sensitive adhesive sheet 1-4 was used.
Comparative examples 1 to 1
Laminate 5 was produced as follows in a manner corresponding to the example of international publication No. 2012/032995.
To 1kg of an acrylic copolymer (1-A-5) obtained by random copolymerization of 75 parts by mass (57 mol%) of 2-ethylhexyl acrylate (Tg: -70 ℃ C.), 20 parts by mass (33 mol%) of vinyl acetate (Tg: 32 ℃ C.) and 5 parts by mass (10 mol%) of acrylic acid (Tg: 106 ℃ C.) as a (meth) acrylic copolymer (1-A) were added 200g of trimethylolpropane triacrylate (1-B-4) as a crosslinking agent (1-B) and 10g of 4-methylbenzophenone (1-C-3) as a photopolymerization initiator (1-C) to prepare a resin composition for an intermediate layer. The resin composition for an intermediate layer was sandwiched between two peeled polyethylene terephthalate films (NP 75Z01, thickness 75 μm/TOYOBO CO., LTD., E7006, thickness 38 μm, manufactured by PANAC CORPORATION), and was shaped into a sheet form to a thickness of 80 μm to prepare an intermediate layer sheet (. alpha.).
Subsequently, 20g of 4-methylbenzophenone (1-C-3) was added and mixed as a photopolymerization initiator (1-C) to 1kg of the acrylic copolymer (1-A-5) to prepare a resin composition for an adhesive layer.
The resin composition for an adhesive layer was sandwiched between two release films, namely two peeled polyethylene terephthalate films ("DIAFOIL MRA" manufactured by Mitsubishi resin corporation, thickness 75 μm/TOYOBO CO., and thickness 38 μm "manufactured by LTD.), and was shaped into a sheet form so that the thickness was 35 μm, thereby producing a resin sheet (β) for an adhesive layer.
Further, the resin composition for adhesive layer was sandwiched between two peeled polyethylene terephthalate films (manufactured by Mitsubishi resin Co., DIAFOIL MRF, thickness 75 μm/TOYOBO CO., manufactured by LTD., thickness 38 μm), and formed into a sheet shape so as to have a thickness of 35 μm, to prepare a resin sheet (β') for adhesive layer.
The PET films on both sides of the intermediate layer sheet (α) were sequentially peeled off and the PET films on one sides of the adhesive layer resin sheets (β) and (β ') were peeled off, and the exposed adhesive surfaces were sequentially bonded to both surfaces of the intermediate layer sheet (α), thereby producing a 3-layer adhesive sheet composed of (β)/(α)/(β').
The amount of accumulated light at a wavelength of 365nm of the PET film remaining on the surfaces of (beta) and (beta') was 1000mJ/cm 2 By the way ofThe pressure-sensitive adhesive sheets 1 to 5 (thickness 150 μm) were prepared by irradiating a high-pressure mercury lamp with ultraviolet rays to crosslink (. alpha.,. beta.') with ultraviolet rays.
Laminates 1 to 5 were produced in the same manner as in example 1-1, except that the pressure-sensitive adhesive sheets 1 to 5 were used.
Comparative examples 1 and 2
1.85g of an isocyanate-based curing agent (trade name "L-45" manufactured by Soken chemical Co., Ltd.) and 0.5g of an epoxy-based curing agent (trade name "E-5 XM" manufactured by Soken chemical Co., Ltd.) were uniformly mixed with 1kg of a commercially available acrylic adhesive (1-A-6) (trade name "SK-DYNE 1882" manufactured by Soken chemical Co., Ltd.) as a (meth) acrylic copolymer (1-A) to prepare adhesive compositions 1-6.
The above compositions 1 to 6 were applied to a release surface of a release film having a thickness of 50 μm, that is, a polyethylene terephthalate film (MRF 75 manufactured by Mitsubishi resin corporation: thickness 75 μm) which had been subjected to a peeling treatment so that the thickness after drying became 75 μm, and the solvent was dried by heating to prepare an adhesive sheet having a thickness of 75 μm.
Further, the above-mentioned compositions 1 to 6 were applied to a release surface of a release film, that is, a polyethylene terephthalate film (100 μm thick "DIAFOIL MRV-V06 manufactured by Mitsubishi resin Co., Ltd.) subjected to a peeling treatment so that the thickness after drying became 75 μm, and the solvent was dried by heating to prepare an adhesive sheet having a thickness of 75 μm.
Two pressure-sensitive adhesive sheets prepared were bonded to each other on their adhesive surfaces and cured for 1 week to prepare pressure-sensitive adhesive sheets 1 to 6 (thickness 150 μm).
A glass plate with a printing step having a non-printing portion of 198mm X148 mm was prepared by printing a glass plate having a peripheral portion (20 mm on the long side and 17mm on the short side) of 238mm X182 mm X0.8 mm thick and not transmitting ultraviolet light and having a thickness of 60 μm.
One of the release films of the pressure-sensitive adhesive sheets 1 to 6 was peeled off, and the sheet was roll-bonded to soda-lime glass 150mm × 200mm thick and 1mm thick.
Next, the remaining release film was peeled off, and after the printed surface of the glass plate with the printed step was pressed and bonded by a vacuum press so that 4 sides of the adhesive surface were laid on the printed step (absolute pressure 5kPa, temperature 80 ℃, pressing pressure 0.04MPa), autoclave treatment (80 ℃, gauge pressure 0.2MPa, 20 minutes) was performed to complete the adhesion, thereby producing laminates 1 to 6.
Comparative examples 1 to 3
Laminates 1-7 were made as follows, in a manner corresponding to the example of WO 2010038366.
Adhesive compositions 1 to 7 were prepared by uniformly mixing 650g of phenoxy resin (1-A-7) (manufactured by InChem Holdings, Inc., PKHH, weight average molecular weight 5.2 ten thousand) as an alternative to (meth) acrylic copolymer (1-A), 1kg of urethane acrylate (1-B-4) having a carbonate skeleton (manufactured by Kokusan Kogyo Co., Ltd., UN5500, weight average molecular weight 6.7 ten thousand) as an alternative to crosslinking agent (1-B), and 43g of 1-cyclohexylphenyl ketone (1-C-4) (manufactured by BASF corporation, Irgacure184) as a photopolymerization initiator (1-C).
The compositions 1 to 7 were shaped into a sheet form in the same manner as in example 1 to prepare adhesive sheets 1 to 7 (thickness: 150 μm).
A glass plate with a printing step having a non-printing portion of 198mm X148 mm was prepared by printing a glass plate having a peripheral portion (20 mm on the long side and 17mm on the short side) of 238mm X182 mm X0.8 mm thick and not transmitting ultraviolet light and having a thickness of 60 μm.
One of the release films of the pressure-sensitive adhesive sheets 1 to 7 was peeled off, and the peeled release film was bonded to soda-lime glass 150mm × 200mm thick and 1mm in thickness by heating at 80 ℃ while rolling.
Then, the remaining release film was peeled off, and after the printed surface of the glass plate with the printed step was pressed and bonded by a vacuum press so that 4 sides of the adhesive surface were laid on the printed step (absolute pressure 5kPa, temperature 80 ℃, lamination pressure 0.04MPa), autoclave treatment (80 ℃, gauge pressure 0.2MPa, 20 minutes) was performed to complete the attachment. From the glass side on which printing was performed, ultraviolet light having a wavelength of 365nm reaching the adhesive sheet reached 2000mJ/cm 2 The adhesive sheet 1-7 was cured by irradiating ultraviolet light with a high-pressure mercury lamp to produce a laminate 1-7.
[ evaluation ]
The pressure-sensitive adhesive sheets and laminates produced in examples and comparative examples were evaluated as follows.
(measurement of viscosity)
Using a plurality of adhesive sheets 1-1 to 1-7 produced in examples and comparative examples, the sheets were laminated to a thickness of 1mm to 2mm, and circular sheets punched out to a diameter of 20mm were produced.
Using a rheometer ("MARS" manufactured by enghong fine co., ltd.) in an adhesion jig: Φ 25mm parallel plate, strain: 0.5%, frequency: 1Hz, temperature rise rate: the complex viscosity of the adhesive sheet before photocuring was measured at from 70 ℃ to 120 ℃ under the condition of 3 ℃/min.
For 1-1 to 1-5 and 1-7, high pressure mercury lamp was used to reach 2000mJ/cm of accumulated light at 365nm 2 In the embodiment (1), the pressure-sensitive adhesive sheet is cured by irradiating the pressure-sensitive adhesive sheet with ultraviolet rays through the polyethylene terephthalate film. The cured adhesive sheets were laminated to a thickness of 1mm to 2mm, and punched out into circular sheets having a diameter of 20 mm.
Using a rheometer ("MARS" manufactured by enghong fine co., ltd.) in an adhesion jig: Φ 25mm parallel plate, strain: 0.5%, frequency: 1Hz, temperature rise rate: the complex viscosity of the pressure-sensitive adhesive sheet after photocuring at 70 ℃ to 120 ℃ was measured at 3 ℃/min.
(adhesion after curing)
One of the release films of the adhesive sheets 1-1 to 1-7 produced in examples and comparative examples was peeled off, and a 50 μm PET film (DIAFOIL T100, thickness 50 μm) as a liner film was laminated to prepare a laminate.
After the laminate was cut into a length of 150mm and a width of 10mm, the remaining release film was peeled off, and the exposed adhesive surface was roll-bonded to soda-lime glass by reciprocating 1 time with a 2kg roll. After the adhesive article was attached by autoclave treatment (80 ℃, gage pressure 0.2MPa, 20 minutes), the cumulative light amount at 365nm reached 2000mJ/cm 2 The pressure-sensitive adhesive sheet was cured by irradiation with ultraviolet rays and cured for 15 hours to prepare a peel force measurement sample.
The peel force (N/cm) of the above peel force measurement sample to glass was measured at a peel angle of 180 DEG and a peel speed of 60 mm/min in an environment of 23 ℃ 40% RH and 80 ℃ 10% RH, and the adhesion after curing was determined.
(adhesion before curing)
One of the release films of the adhesive sheets 1-1 to 1-7 produced in examples and comparative examples was peeled off, and a 50 μm PET film (DIAFOIL T100, 50 μm thick) was laminated as a liner film to prepare a laminate.
After the laminate was cut into a length of 150mm and a width of 10mm, the remaining release film was peeled off, and the exposed adhesive surface was rolled on soda-lime glass by 1 round trip with a 2kg roller.
The adhesion before curing was determined by measuring the peel strength (N/cm) to glass when the adhesion measurement sample was peeled at a peel angle of 180 ℃ and a peel speed of 60 mm/min under an environment of 23 ℃ 40% RH and 80 ℃ 10% RH.
The peeling pattern in the case of peeling at 80 ℃ under 10% RH environment is shown as "CF" in the table for cohesive failure and "AF" in the table for interfacial peeling.
(transparency)
One of the release films of the adhesive sheets 1-1 to 1-7 produced in examples and comparative examples was peeled off, and the exposed adhesive surface roller was bonded to two soda-lime glasses (82mm × 53mm × 0.5mm in thickness), followed by autoclave treatment (80 ℃ C., gauge pressure 0.2MPa, 20 minutes) to complete bonding, thereby producing a laminate for optical evaluation.
The laminate was measured for haze value according to JIS K7136 and total light transmittance (%) according to JIS K7361-1 using a haze meter (NDH 5000, manufactured by nippon electro-color industries, inc.).
(workability of bonding)
In the production of the above-described laminate for optical evaluation, when the sheets produced in examples and comparative examples were bonded to soda-lime glass, the laminate was judged to be "o (excellent)" when it was bonded to a glass plate by roll bonding in an environment of 40% at 23 ℃; the glass plate and the sheet were determined to be "x (inferior)" when they were not closely adhered to each other in an environment of 40% at 23 ℃ and heating was necessary for roll bonding.
(exhaust gas analysis)
According to the present invention, the outgas after the light irradiation refers to outgas detected by the following analysis method.
(exhaust gas generating method)
The adhesive sheets 1-1 to 1-5 and 1-7 prepared in examples and comparative examples were irradiated with 365nm accumulated light to 2000mJ/cm using a high pressure mercury lamp 2 In the embodiment (1), the pressure-sensitive adhesive sheet was irradiated with ultraviolet rays through a polyethylene terephthalate film to prepare a pressure-sensitive adhesive sheet corresponding to the photo-cured product. The photo-cured adhesive sheet was cut into 1cm × 3cm, and put into a 20ml vial (visual bottle) and sealed. The vial was charged into a xenon UV irradiation apparatus (SUNTEST CPS: Toyo essence mechanism) at an illuminance of 765W/m 2 UV irradiation treatment was carried out at 60 ℃ for 24 hours.
The adhesive sheets 1-6 of comparative examples 1-2 were cut into 1cm X3 cm, filled into 20ml vials and sealed. The vial was charged into a xenon UV irradiation apparatus (SUNTEST CPS: Toyo essence mechanism) at an illuminance of 765W/m 2 UV irradiation treatment was carried out at 60 ℃ for 24 hours.
(exhaust gas analysis method)
The gas generated in the UV-treated resin composition as described above can be measured by gas chromatography with a headspace sampler (HS-GC).
(1) Collection of analyte gases
The gas generated from the adhesive sheet was collected under the following conditions.
HS injector: TuboMatrix40(Perkinelmer Co., Ltd.)
2. Heating temperature: 80 deg.C
3. Heating time: 30 minutes
4. Temperature of the sampling needle: 110 deg.C
5. Transmission line temperature: 170 deg.C
6. Injection time: 0.1 minute
7. Column pressure: 16.0psi
(2) GC analysis
The generated gas was analyzed by GC (Perkinelmer Co., Ltd., manufactured by Clarus580), and the amount of exhaust gas generated was determined by conversion into hexadecane.
(concave-convex absorbency)
The laminates 1-1 to 1-7 produced in examples and comparative examples were visually observed, and the case where the adhesive material did not follow the vicinity of the printed level difference and air bubbles remained was judged to be "x (inferior)"; a case where unevenness of residual strain derived from the adhesive sheet was observed in the vicinity of the level difference was determined as "Δ"; the result was judged as "good" when the adhesive tape was smoothly attached without bubbles.
(reliability of resistance to foaming)
The laminates 1-1 to 1-7 prepared in examples and comparative examples were placed in a xenon UV irradiation apparatus (SUNTEST CPS: Toyo Seiki Seisaku Kogyo Co., Ltd.) and observed at an illuminance of 765W/m 2 And appearance after UV irradiation treatment at 60 ℃ for 24 hours.
Judging that bubbles having a diameter of 5mm or more are generated in the adhesive sheet as "x (inferior)"; determining that bubbles with a diameter of 5mm or less are observed as "Δ (normal)"; the case where no foaming was present and the appearance was not changed was judged as "good".
[ Table 1]
Figure GDA0002154617120000841
The numbers in the respective tables indicate parts by mass.
[ Table 2]
Figure GDA0002154617120000842
(investigation)
It is clear from the fact that the peeling mode at high temperature before photocuring was cohesive failure, that the pressure-sensitive adhesive sheets produced in examples 1-1 to 1-4 had excellent wettability to the adherend surface and excellent conformability to uneven surfaces, and also had high adhesion after photocuring. Therefore, the adhesive sheets produced in examples 1-1 to 1-4 were not peeled, foamed, or deformed even under severe environmental tests such as long-term ultraviolet irradiation at high temperatures, and a laminate having high reliability was obtained.
Further, the pressure-sensitive adhesive sheets produced in examples 1-1 to 1-4 were capable of retaining their shapes at 0 to 40 ℃ and showed self-adhesiveness.
In the adhesive sheet of comparative example 1-1, the adhesive resin composition was partially crosslinked by irradiation with ultraviolet rays, that is, in a state after photocuring, and therefore, when the adhesive sheet was laminated on glass with a printed step, unevenness due to residual strain of the adhesive sheet was observed in the vicinity of the printed step, and the lamination appearance was poor. Further, after the photocurable composition is cured again, the adhesive force is low and the cohesive force is poor, so that foaming is observed in the ultraviolet irradiation test and the bonding reliability is also poor.
Since the crosslinking reaction of the adhesive resin composition of comparative examples 1-2 was completed in the stage before the composition was bonded to a member, the viscosity and the adhesive strength did not change even when the composition was irradiated with ultraviolet light. In addition, when the glass laminate is laminated with a glass having a printed step, the adhesive is partially filled in the vicinity of the corner portions where the printed steps are staggered, and air bubbles remain. Further, growth of bubbles was confirmed in the ultraviolet irradiation test from the strain of the adhesive material in the vicinity of the level difference.
Comparative examples 1 to 3 are hot-melt adhesive sheets using an adhesive resin composition having a certain degree of rigidity in a room temperature region without using a (meth) acrylic copolymer as a main component.
The sheets of comparative examples 1 to 3 had a low adhesive force before photocuring, and from this point, it was found that the tackiness at around room temperature was very low and the self-adhesiveness at 0 to 40 ℃ was insufficient as compared with the adhesive sheets of examples. The pressure-sensitive adhesive sheets of comparative examples 1 to 3 required preheating of the adherend from the stage of positioning at the time of bonding, and had inconvenience of complicated operation as compared with the pressure-sensitive adhesive sheets that can be bonded at normal temperature by pressing only.
[ example 2-1]
An acrylic graft copolymer (2-A-1) (weight average molecular weight: 23 ten thousand) 1kg obtained by random copolymerization of 15 parts by mass (18 mol%) of a macromonomer having a number average molecular weight 2900 composed of polymethyl methacrylate (Tg: 105 ℃) and 81 parts by mass (75 mol%) of butyl acrylate (Tg: -55 ℃) and 4 parts by mass (7 mol%) of acrylic acid (Tg: 106 ℃) as a (meth) acrylic copolymer (2-A), 90g of glycerol dimethacrylate (manufactured by Nichikoku Co., Ltd., product name: GMR) (2-B-1) as a crosslinking agent (2-B), and 15g of a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (manufactured by LAMBERTI GRP, product name: ESACURE ZT) (2-C-1) as a photopolymerization initiator (2-C) were uniformly mixed, an adhesive resin composition 2-1 was prepared.
The composition 2-1 was sandwiched between a release-treated polyethylene terephthalate film Y (manufactured by Mitsubishi resin corporation, DIAFOIL MRV-V06, thickness 100 μm, referred to as "release film Y") and a release-treated polyethylene terephthalate film Z (manufactured by Mitsubishi resin corporation, DIAFOIL MRQ, thickness 75 μm, referred to as "release film Z"), and the resulting mixture was shaped into a sheet form to a thickness of 150 μm using a laminator to prepare an adhesive sheet X1 (thickness 150 μm).
A double-sided tape was bonded to one side of a black sheet (LSL-8, manufactured by INOAC Corporation, light transmittance 0%) and the sheet was cut into 50mm × 100mm, and the cut sheet was bonded to the surface of the release film Z laminated on one side of the pressure-sensitive adhesive sheet X1 to form a light-impermeable portion, thereby producing a pressure-sensitive adhesive sheet laminate having a light-permeable portion and a light-impermeable portion in the sheet surface.
Then, from the black sheet side of the adhesive sheet laminate thus produced, the cumulative light amount at a wavelength of 365nm reached 2000mJ/cm using a high-pressure mercury lamp 2 The adhesive sheet 2-1 having a soft portion and a hard portion is produced by irradiating ultraviolet rays to cure the light-transmitting portion of the adhesive sheet laminate. (refer to FIG. 2)
Here, the soft portion refers to a portion of the adhesive sheet that is masked by the black sheet; the hard portion refers to a portion of the adhesive sheet that is not masked by the black sheet.
[ examples 2-2]
1kg of an acrylic copolymer (2-A-2) (weight-average molecular weight: 17 ten thousand) obtained by random copolymerization of 55 parts by mass (36 mol%) of 2-ethylhexyl acrylate (Tg: -70 ℃) and 40 parts by mass (56 mol%) of vinyl acetate (Tg: 32 ℃) and 5 parts by mass (8 mol%) of acrylic acid (Tg: 106 ℃), which are a (meth) acrylic copolymer (2-A), an adhesive resin composition 2-2 was prepared by uniformly mixing 70g of a mixture (2-B-2) (manufactured by Toyo Synthesis Co., Ltd., product name: Aronix M313) of isocyanurate EO-modified diacrylate and isocyanurate EO-modified triacrylate as a crosslinking agent (2-B) and 5g of ESACURE KTO46(2-C-2) (manufactured by LAMBERTI GROUP) as a photopolymerization initiator (2-C).
The composition 2-2 was sandwiched between the release films Y, Z, and shaped into a sheet form to a thickness of 150 μm using a laminator, to prepare a psa sheet X2 (thickness 150 μm).
A psa sheet laminate was produced in the same manner as in example 2-1, except that psa sheet X2 was used, and psa sheet 2-2 having a soft portion and a hard portion was produced in the same manner as in example 2-1.
[ examples 2 to 3]
1kg of an acrylic graft copolymer (2-A-3) (weight-average molecular weight: 23 ten thousand) obtained by random copolymerization of 10 parts by mass (17 mol%) of a polymethyl methacrylate macromonomer (Tg: 105 ℃) having a number-average molecular weight of 1400 and 90 parts by mass (83 mol%) of 2-ethylhexyl acrylate (Tg: -70 ℃) as a (meth) acrylic copolymer (2-A), 50g of tricyclodecane dimethacrylate (product name: DCP) (2-B-3) as a crosslinking agent (2-B) and 15g of a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (product name: ESACURE TZT) (2-C-1) as a photopolymerization initiator (2-C) were uniformly mixed, adhesive resin compositions 2 to 3 were prepared.
The compositions 2 to 3 were sandwiched between the release films Y, Z, and formed into a sheet shape so as to have a thickness of 150 μm using a laminator, to prepare a psa sheet X3 (thickness 150 μm).
A psa sheet laminate was produced in the same manner as in example 2-1, except that psa sheet X3 was used, and a psa sheet 2-3 having a soft portion and a hard portion was produced in the same manner as in example 2-1.
[ examples 2 to 4]
1kg of an acrylic graft copolymer (2-A-4) (weight average molecular weight: 8 ten thousand) obtained by random copolymerization of 12 parts by mass (19 mol%) of a polymethyl methacrylate macromonomer (Tg: 105 ℃) having a number average molecular weight of 2400, 85 parts by mass (74 mol%) of 2-ethylhexyl acrylate (Tg: -70 ℃) and 3 parts by mass (7 mol%) of acrylic acid (Tg: 106 ℃) as a (meth) acrylic copolymer (2-A), 90g of glycerol dimethacrylate (manufactured by Nichikoku Co., Ltd., product name: GMR) (2-B-1) as a crosslinking agent (2-B), and 15g of a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (manufactured by LAMBERTI GROUP product name: ESACURE TZT) (2-C-1) as a photopolymerization initiator (2-C) were uniformly mixed, adhesive resin compositions 2 to4 were prepared.
The compositions 2 to4 were sandwiched between the release films Y, Z, and shaped into a sheet form so as to have a thickness of 150 μm using a laminator, to prepare a psa sheet X4 (thickness 150 μm).
A psa sheet laminate was produced in the same manner as in example 2-1, except that psa sheet X4 was used, and psa sheet 2-4 having a soft portion and a hard portion was produced in the same manner as in example 2-1.
[ examples 2 to 5]
1kg of the acrylic copolymer (2-A-1) (weight-average molecular weight: 23 ten thousand) used in example 2-1, 70g of trimethylolpropane triacrylate (2-B-4) as a crosslinking agent (2-B), and 8g of a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (product name: ESACURE TZT) (2-C-1) as a photopolymerization initiator (2-C) were uniformly mixed to prepare an adhesive resin composition 2-5.
The adhesive resin compositions 2 to 5 were diluted with ethyl acetate to a solution having a solid content concentration of 40%, the solution was applied to a release-treated surface of a release-treated polyethylene terephthalate film Y (manufactured by Mitsubishi resin corporation, DIAFOIL MRV-V06, thickness 100 μm, referred to as "release film Y") so that the dried thickness thereof became 25 μm, and the solution was dried, and then the release-treated polyethylene terephthalate film Z (manufactured by Mitsubishi resin corporation, DIAFOIL MRQ, thickness 75 μm, referred to as "release film Z") was coated on the coated adhesive surface to prepare an adhesive sheet X5 (thickness 25 μm).
A psa sheet laminate was produced in the same manner as in example 2-1, except that psa sheet X5 was used, and psa sheet 2-5 having a soft portion and a hard portion was produced in the same manner as in example 2-1.
Comparative example 2-1
To 1kg of a (meth) acrylic copolymer (2-A-5) obtained by random copolymerization of 75 parts by mass (57 mol%) of 2-ethylhexyl acrylate (Tg: -70 ℃ C.), 20 parts by mass (33 mol%) of vinyl acetate (Tg: 32 ℃ C.) and 5 parts by mass (10 mol%) of acrylic acid (Tg: 106 ℃ C.), 200g of trimethylolpropane triacrylate (2-B-4) and 10g of 4-methylbenzophenone (2-C-3) were mixed and added to prepare a resin composition for an intermediate layer.
The resin composition for an intermediate layer was sandwiched between two peeled polyethylene terephthalate films (NP 75Z01, thickness 75 μm/TOYOBO CO., LTD., E7006, thickness 38 μm, manufactured by PANAC CORPORATION), and was shaped into a sheet form to a thickness of 80 μm to prepare an intermediate layer sheet (. alpha.).
Subsequently, 20g of 4-methylbenzophenone (2-C-3) was added and mixed to 1kg of the acrylic copolymer (2-A-5) as a photopolymerization initiator (2-C) to prepare a resin composition for an adhesive layer.
The adhesive layer resin composition was sandwiched between two peeled polyethylene terephthalate films (DIAFOIL MRA, thickness 75 μm/TOYOBO CO., LTD., thickness 38 μm) and formed into a sheet shape to a thickness of 35 μm to prepare an adhesive layer resin sheet (. beta.).
On the other hand, the adhesive layer resin composition was sandwiched between two peeled polyethylene terephthalate films (manufactured by Mitsubishi resin corporation, DIAFOIL MRF, thickness 75 μm/TOYOBO CO., LTD., E7006, thickness 38 μm), and formed into a sheet shape to a thickness of 35 μm to prepare an adhesive layer resin sheet (. beta.').
The PET films on both sides of the intermediate layer sheet (α) were sequentially peeled off and removed, and the PET films on one sides of the adhesive layer resin sheets (β) and (β ') were peeled off, and the exposed adhesive surfaces were sequentially bonded to both surfaces of the intermediate layer sheet (α), thereby producing a 3-layer adhesive sheet composed of (β)/(α)/(β').
The accumulated light quantity at 365nm of the PET film through the surface of the film (beta) and (beta') is 1000mJ/cm 2 The pressure-sensitive adhesive sheet X6 (thickness 150 μm) was prepared by irradiating a high-pressure mercury lamp with ultraviolet light to crosslink (. alpha.,. beta. ') and (. beta.') with ultraviolet light.
A double-sided tape was bonded to one side of a black sheet (LSL-8, manufactured by INOAC Corporation, light transmittance 0%) and cut into 50mm × 100mm pieces, which were bonded to the surface of the polyethylene terephthalate film (DIAFOIL MRF) subjected to the peeling treatment on one side of the pressure-sensitive adhesive sheet X6, thereby forming a light-impermeable portion, and a pressure-sensitive adhesive sheet laminate having a light-permeable portion and a light-impermeable portion in the sheet surface was produced.
Then, from the black sheet side of the adhesive sheet laminate thus produced, a high pressure mercury lamp was used to obtain a cumulative light amount of 2000mJ/cm at a wavelength of 365nm 2 The adhesive sheet 2-6 is produced by irradiating the adhesive material at the portion in contact with the light-transmitting portion of the laminate with ultraviolet light and further irradiating the adhesive material with light.
Comparative examples 2 and 2
An adhesive resin composition 2-7 was prepared by uniformly mixing 650g of phenoxy resin (2-A-6) (manufactured by InChem Holdings, Inc., PKHH, weight average molecular weight 5.2 ten thousand) and 1kg of urethane acrylate (2-B-4) (manufactured by Kayaku Kogyo Co., Ltd., UN5500, weight average molecular weight 6.7 ten thousand) having a carbonate skeleton as a substitute for the crosslinking agent (2-B) and 43g of 1-cyclohexylphenylketone (2-C-4) (manufactured by BASF corporation, Irgacure184) as a photopolymerization initiator (2-C).
The compositions 2 to 7 were sandwiched between two peeled polyethylene terephthalate films (DIAFOIL MRV-V06, thickness 100 μm/DIAFOIL MRQ, thickness 75 μm manufactured by Mitsubishi resin Co., Ltd.), and shaped into a sheet form so as to have a thickness of 150 μm using a laminator to prepare an adhesive sheet X7 (thickness 150 μm).
A pressure-sensitive adhesive sheet laminate having a light-transmitting portion and a light-impermeable portion in the sheet surface was produced by bonding a double-sided tape to one side of a black sheet (LSL-8, manufactured by INOAC Corporation, light transmittance 0%) and cutting the black sheet into a 50mm × 100mm sheet, and bonding the 50mm × 100mm sheet to the surface of the peeled polyethylene terephthalate film (DIAFOIL MRQ, manufactured by mitsubishi resin Corporation) on one side of the pressure-sensitive adhesive sheet X7 to form a light-impermeable portion.
Then, from the black sheet side of the adhesive sheet laminate thus produced, a high pressure mercury lamp was used to obtain a cumulative light amount of 2000mJ/cm at a wavelength of 365nm 2 The adhesive sheet 2-7 was produced by curing the light-transmitting portion of the adhesive sheet laminate by irradiation with ultraviolet light.
Comparative examples 2 to 3
1.85g of an isocyanate-based curing agent (trade name "L-45" manufactured by Soken chemical Co., Ltd.) and 0.5g of an epoxy-based curing agent (trade name "E-5 XM" manufactured by Soken chemical Co., Ltd.) were uniformly mixed with 1kg of a commercially available acrylic adhesive (2-A-7) (trade name "SK-DYNE 1882" manufactured by Soken chemical Co., Ltd.) to prepare an adhesive resin composition 2-6.
The aforementioned compositions 2 to 6 were applied to a release surface of a polyethylene terephthalate film (trade name "MRF 75": manufactured by Mitsubishi resin Co., Ltd.) having a thickness of 50 μm and subjected to a peeling treatment so that the thickness after drying became 75 μm, and the solvent was dried by heating to prepare an adhesive sheet having a thickness of 75 μm.
Further, the above-mentioned compositions 2 to 6 were applied to a release surface of a polyethylene terephthalate film (DIAFOIL MRV-V06, thickness 100 μm, manufactured by Mitsubishi resin Co., Ltd.) subjected to a peeling treatment so that the thickness after drying became 75 μm, and the solvent was dried by heating to prepare an adhesive sheet having a thickness of 75 μm.
Two adhesive sheets were prepared, and the adhesive surfaces were adhered and cured for one week to react the curing agent, thereby preparing adhesive sheets 2 to 8 (thickness 150 μm).
[ evaluation ]
The adhesive sheets 2-1 to 2-8 prepared in examples and comparative examples were measured and evaluated for various physical property values as follows.
(gel fraction)
The following measurements were carried out on samples of the pressure-sensitive adhesive sheets 2-1 to 2-7 produced in examples and comparative examples, which were respectively taken from the hard portion, which was the portion in contact with the light-transmitting portion, and the soft portion, which was the portion not in contact with the light-transmitting portion.
The following measurements were carried out on arbitrary sites of the pressure-sensitive adhesive sheets 2 to 8 of comparative examples 2 to 3.
1) The adhesive composition (W1) was weighed and wrapped in a SUS mesh (W0) of 200 mesh, the weight of which was measured in advance.
2) The SUS net was immersed in 100mL of ethyl acetate for 24 hours.
3) The SUS net was taken out and dried at 75 ℃ for 4 hours and a half.
4) The weight (W2) after drying was obtained, and the gel fraction of the adhesive composition was measured by the following formula.
Gel fraction (%) < 100 × (W2-W0)/W1
(glass transition temperature (Tg))
The temperature was measured at a temperature increase rate of 5 ℃/min in accordance with JIS K-7121(ISO3146) using a differential scanning calorimetry apparatus (DSC-8500) manufactured by PerkinElmer co., ltd., and the glass transition temperature (Tg) of each of the portions of the adhesive sheets 2-1 to 2-7 that contact the light transmitting portions, that is, the hard portions and the portions that do not contact the light transmitting portions, that is, the soft portions was determined from the obtained thermograms.
The same measurements were carried out on arbitrary sites of the pressure-sensitive adhesive sheets 2 to 8 of comparative examples 2 to 3.
(ASKER hardness)
The release films of the release sheets were sequentially stacked on the exposed adhesive surfaces of the soft portions of the adhesive sheets 2-1 to 2-7 produced in examples and comparative examples, which are portions not in contact with the light-transmitting portions, and a plurality of adhesive sheets were stacked so that the total thickness was in the range of 5mm to 7 mm. This can reduce the influence of the hardness of the stage on which the measurement sample is placed, and can compare and measure indentation hardness specific to the material. Further, the exposed adhesive surface of the laminated adhesive sheet was pressed at a rate of 3 mm/min vertically downward with a load of 1kg against the tip terminal of an ASKER C2L durometer gauge, and the C2ASKER hardness (C) of the soft portion was measured.
The adhesive sheets 2-1 to 2-7 prepared in examples and comparative examples were laminated so that the thickness of the hard portion, which is the portion in contact with the light-transmitting portion, was within the range of 5mm to 7mm, and the C2ask hardness (d) of the hard portion was measured.
The same measurement was performed for any part of the pressure-sensitive adhesive sheets 2 to 8 produced in comparative examples 2 to 3.
(180 ℃ Peel force of Soft portion)
The adhesive sheets 2-1 to 2-7 produced in examples and comparative examples were cut out at the portions not in contact with the light-transmitting portions, i.e., the soft portions, and one of the release films was peeled off to prepare a laminate by laminating a 50 μm PET film (available from mitsubil corporation, DIAFOIL T100, thickness 50 μm) as a liner film.
After the laminate was cut into a length of 150mm and a width of 10mm, the remaining release film was peeled off, and the exposed adhesive surface was rolled on soda-lime glass by 1 round trip with a 2kg roller.
The adhesive force measurement sample was subjected to peeling at a peeling angle of 180 degrees and a peeling speed of 60 mm/min under an environment of 23 ℃ and 40% RH, and the peeling force (N/cm) against glass was measured to obtain the 180-degree peeling force of the soft portion which is a portion not in contact with the light-transmitting portion.
(180 degree peeling force of hard portion)
A laminate was prepared by peeling off one of the release films from the pressure-sensitive adhesive sheets X1-7 prepared in examples 2-2-1 to4 and comparative examples 2-1 and 2-2 in a state before irradiation with light, and then laminating a 50 μm PET film (DIAFOIL T100, 50 μm, manufactured by Mitsubishi resin corporation) as a liner film.
After the laminate was cut into a length of 150mm and a width of 10mm, the remaining release film was peeled off, and the exposed adhesive surface was pressure-bonded to soda-lime glass by 1 round trip with a 2kg roller. After the adhesive article was attached by autoclave treatment (80 ℃, gage pressure 0.2MPa, 20 minutes), the cumulative light amount at 365nm reached 2000mJ/cm 2 The pressure-sensitive adhesive sheet was cured by irradiation with ultraviolet rays and cured for 15 hours to obtain a peel force measurement sample.
The peeling force (N/cm) to glass when the above peeling force measurement sample was peeled at a peeling angle of 180 degrees and a peeling speed of 60 mm/min under an environment of 23 ℃ and 40% RH was measured, and the 180 DEG peeling force of the hard portion, which is a portion in contact with the light-transmitting portion, was determined.
The pressure-sensitive adhesive sheets 2 to 8 produced in comparative examples 2 to 3 were cut at arbitrary positions and measured in the same manner as the procedure for the 180 ℃ peel force of the soft part.
(Retention force of Soft portion)
The pressure-sensitive adhesive sheets 2-1 to 2-7 produced in examples and comparative examples were cut into strips of 25mm in width by 100mm in length by cutting the soft portions, which were portions not in contact with the light-transmitting portions, into 50mm by 100mm, peeling off the release film on one side, and attaching the adhesive sheets with a hand roll so that one side of the adhesive sheets was overlapped with a polyethylene terephthalate film (38 μm in thickness) for a liner, thereby obtaining test pieces.
Then, the remaining release film was peeled off, and the SUS plate (thickness 120mm, 5 mm. times.1.5 mm) vertically placed was attached with a hand roller so that the test piece was overlapped only by a length of 20 mm. At this time, the attached area of the transparent double-sided adhesive sheet to the SUS plate was 25mm × 20 mm.
Thereafter, the test piece was cured at 40 ℃ and 70 ℃ for 15 minutes, and then a 4.9N weight was hung on the test piece in the vertical direction and left standing for 30 minutes, and then the length (mm) of the downward deviation of the position of attachment of SUS to the test piece was measured. In the case where the attachment surface was deviated and the weight was dropped, the time required for the weight to drop was measured.
The pressure-sensitive adhesive sheet 2-7 of comparative example 2-2 was not self-adhesive, and therefore, a test piece laminated on a SUS plate was preheated at 80 ℃ for 5 minutes to adhere to an adherend and then the holding power was measured.
(holding power of hard portion)
With respect to the pressure-sensitive adhesive sheets X1 to 7 before light irradiation prepared in examples 2-2-1 to 5 and comparative examples 2-1 and 2-2, laminates of SUS and test pieces were prepared in the same manner as the measurement of the holding power before light curing, and then ultraviolet rays having a wavelength of 365nm reaching the pressure-sensitive adhesive sheets were made to reach 2000mJ/cm 2 In the embodiment (1), while confirming the accumulated light amount with a light meter (U.S. instrument 250/detector: UVD-C365, manufactured by USHIO INC.), ultraviolet rays were irradiated from the polyethylene terephthalate film side used for the liner with a high-pressure mercury lamp, and an adhesive sheet corresponding to a hard portion, which is a portion in contact with the light transmitting portion, was produced.
Thereafter, the test piece was cured at 40 ℃ and 70 ℃ for 15 minutes, and then a 4.9N weight was hung on the test piece in the vertical direction and left standing for 30 minutes, and then the length (mm) of the downward deviation of the position of attachment of SUS to the test piece was measured.
For test pieces that were essentially stationary, the offset length was below 0.1mm, and is reported as "< 0.1 mm" in Table 3.
The adhesive sheets 2 to 8 produced in comparative examples 2 to 3 were cut at arbitrary positions and then measured in the same manner as the procedure for measuring the holding power of the soft portion.
(transparency)
One of the release films was peeled off from the hard portion of the adhesive sheets 2-1 to 2-7 produced in examples and comparative examples, which portion was in contact with the light-transmitting portion, and the exposed adhesive surface roller was bonded to two pieces of soda-lime glass (82mm × 53mm × 0.5mm in thickness), followed by autoclave treatment (80 ℃, 0.2MPa gage pressure, 20 minutes) to complete bonding, thereby producing a laminate for optical evaluation.
Samples were similarly prepared for arbitrary sites of the adhesive sheets 2 to 8 prepared in comparative examples 2 to 3.
The laminate was measured for haze value according to JIS K7136 and total light transmittance (%) according to JIS K7361-1 using a haze meter (NDH 5000, manufactured by nippon electro-color industries, inc.).
(concave-convex absorbency)
The pressure-sensitive adhesive sheets X1 to4, 6 and 7 prepared in examples 2-1 to 2-4 and comparative examples 2-1 and 2-2 in a state before light irradiation were cut into pieces of 50 mm. times.80 mm, and the printed surface of soda-lime glass (82 mm. times.53 mm. times.0.5 mm thick) having a thickness of 80 μm printed on the peripheral portion of 3mm of the pressure-sensitive adhesive surface exposed by peeling off one release film was subjected to pressure bonding using a vacuum press so that 4 sides of the pressure-sensitive adhesive material were laid on the printing step (absolute pressure 5kPa, temperature 80 ℃ C., pressure 0.04 MPa). Subsequently, the remaining release film was peeled off, and a ZEONOR film (100 μm thick, manufactured by ZEON CORPORATION) was press-bonded, followed by autoclave treatment (80 ℃, gage pressure 0.2MPa, 20 minutes) to complete the bonding. From the side of the printed soda-lime glass, ultraviolet light having a wavelength of 365nm reaching the sheet X reached 2000mJ/cm 2 The method (2) is to irradiate ultraviolet light with a high-pressure mercury lamp so as to form an opening part where no printing is performed,That is, the sheet of the portion in contact with the light-transmitting portion was cured to produce laminates 2-1 to 2-6 for evaluation.
For the pressure-sensitive adhesive sheet X5 produced in example 2-5, a laminate 2-7 for evaluation was produced in the same manner as above, using soda-lime glass printed with a thickness of 15 μm.
With respect to the adhesive sheets 2 to 8 produced in comparative examples 2 to 3, laminates of soda-lime glass and ZEONOR films (100 μm thick, manufactured by ZEON CORPORATION) on which printing was performed were produced in the same order as described above using the adhesive sheets 2 to 7, and then, the laminates were completed by autoclave treatment (80 ℃, gauge pressure of 0.2MPa, 20 minutes), and laminates for evaluation 2 to 8 were produced.
The produced laminates 2-1 to 2-8 were visually observed, and the laminates were judged to have "x" when the adhesive material did not follow the printed level difference and air bubbles remained; the film was judged to have "Δ" in the case where unevenness due to bending or deformation of the film in the vicinity of the height difference was observed; the case where the adhesive tape was smoothly attached without bubbles was determined to be "o".
(reliability of resistance to foaming)
The laminates 2-1 to 2-8 for evaluation prepared in the evaluation of the uneven absorbency were put into a constant temperature and humidity chamber at 85 ℃ and 85% RH, and the appearance after 100 hours of curing was observed. The occurrence of bubbles in the adhesive sheet was judged as "x"; the case where the appearance was not changed was judged as "o".
[ Table 3]
Figure GDA0002154617120000961
[ Table 4]
Figure GDA0002154617120000962
(investigation)
The adhesive sheets produced in examples 2-1 to 2-5 exhibited high fluidity by heating because the gel fraction of the soft part was less than 1%. Therefore, by heating and melting the adhesive at the time of bonding, not only is excellent in conformability to uneven surfaces, but also even if one of the adherends is a low-rigidity material such as a thin film, a smooth laminate can be obtained without causing bending in the vicinity of the step. Further, since the hard portion has a gel fraction of 40% or more, it exhibits high cohesive force even under severe environmental tests such as high-temperature and high-humidity conditions, and a highly reliable laminate can be obtained without peeling, foaming, or deformation.
In the adhesive sheet of comparative example 2-1, since the adhesive resin composition was partially crosslinked by irradiation with ultraviolet rays, when the adhesive sheet was laminated with a glass and a film having a printed step, irregularities due to the printed step were transferred to the film side, and a smooth laminate could not be obtained. Further, it was confirmed that the adhesive material was foamed under the high temperature and high humidity test with the strain of the adhesive material around the level difference as a starting point, and the storage stability was poor.
Comparative example 2-2 is a hot-melt adhesive sheet using an adhesive resin composition having a certain degree of rigidity in a room temperature region without using a (meth) acrylic copolymer.
With the sheet of comparative example 2-2, the tackiness at around room temperature was very low as compared with the pressure-sensitive adhesive sheet of example. When the glass with the printed step was laminated with the sheet, since fluidity during heating was low, unevenness due to the printed step was slightly transferred to one side, and as a result, the laminate was inferior in smoothness to the adhesive sheet of example. Further, since the sheet has high rigidity and is not self-adhesive during the bonding operation, it is necessary to preheat the adherend from the stage of positioning during the bonding operation, and there is a problem that the operation is complicated as compared with an adhesive sheet that can be bonded at normal temperature only by pressing, as is apparent from the fact that ASKER hardness in opaque parts is high.
In comparative examples 2 to 3, since the crosslinking reaction of the adhesive resin composition of the adhesive sheets 2 to 7 was already completed, there was no soft part having a gel fraction of 1% or less in the adhesive sheet, and not only was unevenness due to the printing step transferred to the film side and a smooth laminate could not be obtained, but also, as a result, bubbles remained without completely filling a part of the adhesive in the vicinity of the corner portions where the printing steps are staggered.
From the results of the above examples and the test results carried out by the present inventors up to now, it is considered that when a photocurable transparent double-sided adhesive sheet including a soft portion having a gel fraction of less than 1% and a hard portion having a gel fraction of 40% or more and including a (meth) acrylic copolymer is used, 2 image display device constituent members can be suitably bonded in the same manner as in the examples.
It is considered that the gel fraction of the soft portion in the surface of the pressure-sensitive adhesive sheet is preferably less than 1%, and the gel fraction of the hard portion is preferably 40% or more.
It is also found that the glass transition temperature (measured Tg) of the soft part in the surface of the pressure-sensitive adhesive sheet is preferably-70 to-10 ℃, the glass transition temperature (measured Tg) of the hard part is-60 to +20 ℃, and the difference (Tg H-Tg S) between the glass transition temperature (Tg H) of the hard part and the glass transition temperature (Tg S) of the soft part is preferably 3 ℃ or more.
[ examples 2 to 6]
For the adhesive sheet X1 produced in example 2-1, a long laminate sheet having a width of 150mm and a length of 100m was wound around a plastic core having a diameter of 6 inches under an initial winding tension of 70N and a taper ratio of 20%, to produce an adhesive sheet roll.
The end face of the produced roll was irradiated with a high-pressure mercury lamp to obtain a cumulative light intensity of 500mJ/cm at a wavelength of 365nm 2 The method (4) is a method in which light irradiation is performed to photocure the end surface portion, thereby obtaining an adhesive sheet roll having a hard portion on the end surface portion.
Comparative examples 2 to4
Adhesive sheet rolls were produced in the same manner as in examples 2 to 6, except that no light was applied.
The pressure-sensitive adhesive sheet rolls of comparative examples 2 to4 and examples 2 to 6, which were produced in this way and had no hard portion but only a soft portion, were stored in a constant temperature and humidity chamber at 40 ℃ and 90% RH for 2 weeks, and then the end surfaces of the pressure-sensitive adhesive sheet rolls were visually observed.
While the adhesive sheet rolls of examples 2 to 5 having the hard portions at the end surfaces did not cause the adhesive to flow out from the end surfaces, and the sheet was excellent in winding workability, the end surfaces of the adhesive sheet rolls of comparative examples 2 to4 composed of only soft portions were sticky due to the flow out of the adhesive, and as a result, the winding workability was hindered.
[ example 3-1]
As the (meth) acrylic copolymer (3-A), a graft copolymer (3-A1) was used which was obtained by random copolymerization of 15 parts by mass (18 mol%) of a polymethyl methacrylate macromonomer (Tg: 105 ℃ C., number average molecular weight 2400) and 81 parts by mass (75 mol%) of butyl acrylate (Tg: -55 ℃ C.) and 4 parts by mass (7 mol%) of acrylic acid (Tg: 106 ℃ C.).
In the graft copolymer (3-A1), the glass transition temperature of the copolymer constituting the main component was-60 ℃, the content of the macromonomer in the graft copolymer (3-A1) was 15 mass%, the complex viscosity at 130 ℃ and the frequency of 0.02Hz was 260 pas.
1kg of the graft copolymer (3-A1), 90g of glycerol dimethacrylate (GMR) as a crosslinking agent (3-B), and 15g of a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (ESACURE TZT, product name: LAMBERTI GROUP) as a photopolymerization initiator (3-C) were uniformly mixed to prepare an adhesive resin composition 3-1.
The adhesive resin composition 3-1 was sandwiched between two release films, i.e., two polyethylene terephthalate films (DIAFOIL MRV-V06 manufactured by Mitsubishi resin corporation, "DIAFOIL MRQ" manufactured by Mitsubishi resin corporation, thickness 100 μm/DIAFOIL MRQ manufactured by Mitsubishi resin corporation, thickness 75 μm), and shaped into a sheet form so as to have a thickness of 150 μm using a laminator, thereby producing an adhesive sheet 3-1 (thickness 150 μm).
[ examples 3-2]
An adhesive resin composition 3-2 was prepared in the same manner as in example 3-1, except that 90g of glycerol dimethacrylate (product name: NK ESTER 701, manufactured by NONSHOM CHEMICAL INDUSTRIAL CO., LTD.) (3-B-1) was used as the crosslinking agent (3-B).
Using the adhesive resin composition 3-2, an adhesive sheet 3-2 (thickness 150 μm) was produced in the same manner as in example 3-1.
[ examples 3 to 3]
1kg of the same graft copolymer (3-A1) as in example 3-1, 90g of glycerol dimethacrylate (manufactured by Nichikura, Ltd., product name: GMR) as a crosslinking agent (3-B), 15g of a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (manufactured by LAMBERTI GROUP, product name: ESACURE TZT) as a photopolymerization initiator (3-C) and 50g of an ultraviolet stabilizer (manufactured by Ciba Japan, product name: TIN123) were uniformly mixed to prepare an adhesive resin composition 3-3.
Further, using this adhesive resin composition 3-3, an adhesive sheet 3-3 (thickness 150 μm) was produced in the same manner as in example 3-1.
[ examples 3 to 4]
As the (meth) acrylic copolymer (3-A), a graft copolymer (3-A2) was used which was obtained by random copolymerization of 10 parts by mass (12 mol%) of a polymethyl methacrylate macromonomer (Tg: 105 ℃ C., number average molecular weight 2500) with 88 parts by mass (84 mol%) of butyl acrylate (Tg: -55 ℃ C.) and 2 parts by mass (7 mol%) of acrylic acid (Tg: 106 ℃ C.).
In the graft copolymer (3-A2), the glass transition temperature of the copolymer constituting the main component was-60 ℃, the content of the macromonomer in the graft copolymer (3-A2) was 10% by mass, and the complex viscosity at 130 ℃ and a frequency of 0.02Hz was 240 pas.
Adhesive resin compositions 3 to4 were prepared by mixing 1kg of the graft copolymer (3-A2), 50g of trimethylolpropane triacrylate (product name: CLM400, manufactured by Ningmura chemical industries Co., Ltd.) as a crosslinking agent (3-B), and 15g of a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (product name: ESACURE TZT, manufactured by LAMBERTI GROUP) as a photopolymerization initiator (3-C).
Further, using this adhesive resin composition 3-4, an adhesive sheet 3-4 (thickness 150 μm) was produced in the same manner as in example 3-1.
[ examples 3 to 5]
As the (meth) acrylic copolymer (3-A), a graft copolymer (3-A3) was used which was obtained by random copolymerization of 8 parts by mass (10 mol%) of a polymethyl methacrylate macromonomer (Tg: 105 ℃ C., number average molecular weight 2500) and 89 parts by mass (85 mol%) of butyl acrylate (Tg: -55 ℃ C.) and 3 parts by mass (5 mol%) of acrylic acid (Tg: 106 ℃ C.).
In the graft copolymer (3-A3), the glass transition temperature of the copolymer constituting the main component was-40 ℃, the content of the macromonomer in the graft copolymer (3-A3) was 8 mass%, and the complex viscosity at 130 ℃ and a frequency of 0.02Hz was 220 pas.
1kg of the graft copolymer (3-A3), 90g of glycerol dimethacrylate (GMR) as a crosslinking agent (3-B), and 15g of a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (ESACURE TZT, product name: LAMBERTI GROUP) as a photopolymerization initiator (3-C) were uniformly mixed to prepare an adhesive resin composition 3-5.
Further, using this adhesive resin composition 3-5, an adhesive sheet 3-5 (thickness 150 μm) was produced in the same manner as in example 3-1.
Comparative example 3-1
An example corresponding to International publication No. 2012/032995 was produced.
Specifically, 1kg of an acrylic copolymer (3-A-5) obtained by random copolymerization of 75 parts by mass (57 mol%) of 2-ethylhexyl acrylate (Tg: -70 ℃ C.), 20 parts by mass (33 mol%) of vinyl acetate (Tg: 32 ℃ C.) and 5 parts by mass (10 mol%) of acrylic acid (Tg: 106 ℃ C.) as a (meth) acrylic copolymer (3-A) was mixed with 200g of trimethylolpropane triacrylate (3-B-4) as a crosslinking agent (3-B) and 10g of 4-methylbenzophenone (3-C-3) as a photopolymerization initiator (3-C) to prepare a resin composition for an intermediate layer.
The resin composition for an intermediate layer was sandwiched between two peeled polyethylene terephthalate films (NP 75Z01, thickness 75 μm/TOYOBO CO., LTD., E7006, thickness 38 μm, manufactured by PANAC CORPORATION), and was shaped into a sheet form to a thickness of 80 μm to prepare an intermediate layer sheet (. alpha.).
Subsequently, 20g of 4-methylbenzophenone (3-C-3) was added and mixed as a photopolymerization initiator (3-C) to 1kg of the acrylic copolymer (3-A-5) to prepare a resin composition for an adhesive layer.
The resin composition for an adhesive layer was sandwiched between two release films, namely two peeled polyethylene terephthalate films ("DIAFOIL MRA" manufactured by Mitsubishi resin corporation, thickness 75 μm/TOYOBO CO., and thickness 38 μm "manufactured by LTD.), and was shaped into a sheet form so that the thickness was 35 μm, thereby producing a resin sheet (β) for an adhesive layer.
Further, the resin composition for adhesive layer was sandwiched between two peeled polyethylene terephthalate films (manufactured by Mitsubishi resin Co., DIAFOIL MRF, thickness 75 μm/TOYOBO CO., LTD., E7006, thickness 38 μm), and formed into a sheet shape to a thickness of 35 μm to prepare a resin sheet (β') for adhesive layer.
The PET films on both sides of the intermediate layer sheet (α) were sequentially peeled off and removed, and the PET films on one sides of the adhesive layer resin sheets (β) and (β ') were peeled off, and the exposed adhesive surfaces were sequentially bonded to both surfaces of the intermediate layer sheet (α), thereby producing a 3-layer adhesive sheet composed of (β)/(α)/(β').
The accumulated light quantity at 365nm of the PET film through the surface of the film (beta) and (beta') is 1000mJ/cm 2 The adhesive sheets 3 to 6 (thickness 150 μm) were prepared by irradiating ultraviolet light with a high-pressure mercury lamp to crosslink (. alpha.,. beta. ') and (. beta.') with ultraviolet light.
Comparative examples 3 and 2
An adhesive sheet was produced according to example 6 of WO 2010/038366.
That is, an adhesive resin composition 3-7 was prepared by uniformly mixing 650g of phenoxy resin (manufactured by InChem Holdings, Inc., PKHH, weight average molecular weight 5.2 ten thousand) as an alternative to the (meth) acrylic copolymer (3-A), 1kg of urethane acrylate having a carbonate skeleton (manufactured by Kokusho Kogyo Co., Ltd., UN5500, weight average molecular weight 6.7 ten thousand) as an alternative to the crosslinking agent (3-B), and 43g of 1-cyclohexylphenylketone (manufactured by BASF, Irgacure184) as a photopolymerization initiator (3-C).
A pressure-sensitive adhesive sheet 3-7 (thickness 150 μm) was produced for the composition 3-7 in the same manner as in example 3-1.
[ evaluation ]
The pressure-sensitive adhesive sheets and laminates produced in examples and comparative examples were evaluated as follows.
(tensile modulus, breaking Strength, elongation at Break)
The pressure-sensitive adhesive sheets 3-1 to 3-7 were cut to a width of 20mm to obtain a tensile test specimen before photocrosslinking.
Cutting the adhesive sheets 3-1 to 3-7 to a width of 20mm, and obtaining a cumulative light amount of 2000mJ/cm at 365nm 2 In the embodiment (1), the pressure-sensitive adhesive sheet was cured by irradiation with ultraviolet light from the release PET side using a high-pressure mercury lamp, and cured at 23 ℃ and 50% RH for 15 hours to obtain a tensile test measurement sample after photocrosslinking.
The tensile test measurement specimen was measured for tensile modulus, tensile strength at break and tensile elongation at break at a test speed of 300 mm/min under an environment of 23 ℃ and 50% RH.
The displacement under the tensile modulus measurement condition is 30 to 50 mm.
(gel fraction)
The following measurements were carried out on samples taken from the portions of the pressure-sensitive adhesive sheets 3-1 to 3-7 produced in examples and comparative examples, which portions were in contact with the light-transmitting portions, i.e., the hard portions, and the portions which were not in contact with the light-transmitting portions, i.e., the soft portions.
1) The adhesive resin composition (W1) was weighed and wrapped in a SUS mesh (W0) of 200 mesh, the weight of which was measured in advance.
2) The SUS net was immersed in 100mL of ethyl acetate for 24 hours.
3) The SUS net was taken out and dried at 75 ℃ for 4 hours and a half.
4) The weight (W2) after drying was obtained, and the gel fraction of the binder resin composition was measured by the following formula.
Gel fraction (%) < 100 × (W2-W0)/W1
(operability (conservation))
Adhesive sheets 3-1 to 3-7 cut into a square of 50mm × 50mm were sandwiched between two glass plates of 100mm × 100mm square and 2mm in thickness to produce a laminate. A 500g weight was placed on the laminate, and after standing at 60 ℃ for 24 hours, the laminate was visually observed for the presence of an adhesive overflow.
The laminate thus produced was visually observed, and the overflow of the entire adhesive was judged as "x"; the case where the adhesive overflows only at the corners was judged as "Δ"; the case where the adhesive did not overflow was judged as "O".
(differential height absorbency)
The pressure-sensitive adhesive sheets 3-1 to 3-6 prepared in examples 3-1 to 3-5 and comparative example 3-1 in the state before light irradiation were cut into 50mm × 80mm pieces, and the printed surface of soda-lime glass (82mm × 53mm × 0.5mm thick) having a thickness of 80 μm printed on the peripheral portion 3mm was pressed and bonded by a vacuum press so that 4 sides of the pressure-sensitive adhesive material were laid on the printing step (absolute pressure 5kPa, temperature 80 ℃, pressing pressure 0.04 MPa). Subsequently, the remaining release film was peeled off, and a ZEONOR film (manufactured by ZEON CORPORATION, 100 μm thick) was laminated and attached, followed by autoclave treatment (80 ℃, gauge pressure of 0.2MPa, 20 minutes) to complete the attachment.
Then, ultraviolet light having a wavelength of 365nm reaching the sheet X was irradiated from the side of the printed soda-lime glass to 2000mJ/cm 2 The laminates 3-1 to 3-6 for evaluation were produced by irradiating a high-pressure mercury lamp with ultraviolet rays to cure the sheet at the portions in contact with the light-transmitting portions, i.e., the openings where printing was not performed.
With respect to the adhesive sheet 3-7 produced in comparative example 3-2, a laminate of soda-lime glass and a ZEONOR film (100 μm thick, manufactured by ZEON CORPORATION) printed using the adhesive sheet 3-7 was produced in the same order as described above, and then subjected to autoclave treatment (80 ℃, 0.2MPa gauge pressure, 20 minutes) to complete the sticking, thereby producing a laminate for evaluation 3-7.
The produced laminates 3-1 to 3-7 were visually observed, and the laminates were judged to have "x" when the adhesive material did not follow the printed step and air bubbles remained; a case where unevenness due to bending or deformation of the film in the vicinity of the level difference was observed was judged as "Δ"; the case where the adhesive tape was smoothly attached without bubbles was determined to be "o".
[ Table 5]
Figure GDA0002154617120001041
The adhesive sheets prepared in examples 3-1 to 3-5 exhibited a large change in tensile properties before and after photocuring. With such characteristics, it was confirmed that the pressure-sensitive adhesive sheets produced in examples 3-1 to 3-5 can have excellent step absorption before photocuring and excellent foaming resistance after photocuring.
On the other hand, in comparative example, the change in tensile properties before and after photocuring was insufficient, and therefore, in comparative example 3-1, the change after photocrosslinking was insufficient, and thus, a sheet having poor reliability was obtained, and in comparative example 3-2, a sheet having poor handling properties (storage properties) before photocrosslinking was obtained.

Claims (4)

1. A photocurable curable adhesive sheet which is an adhesive sheet in an uncrosslinked state before photocrosslinking and which is formed from a resin composition comprising 100 parts by mass of a (meth) acrylic copolymer (A), 0.5 to 20 parts by mass of a crosslinking agent (B), and 0.1 to 5 parts by mass of a photopolymerization initiator (C), wherein the crosslinking agent (B) is a polyfunctional (meth) acrylate having 2 or more (meth) acryloyl groups,
a tensile modulus (X) of the curable adhesive sheet before photocrosslinking 1 ) Tensile modulus (X) after photocrosslinking 2 ) Ratio of (X) 2 /X 1 ) Is 3 or more, and has hot melt property.
2. The adhesive sheet according to claim 1, wherein the (meth) acrylic copolymer (A) is a graft copolymer having a macromonomer as a branched component, and the macromonomer is contained at a ratio of 5 to 30 mass%.
3. The adhesive sheet according to claim 1, wherein the gel fraction (a) of the adhesive sheet before photocuring is 0%.
4. A laminate for image display device construction, characterized by having a structure in which 2 image display device components are laminated with the photocurable adhesive sheet according to any one of claims 1 to 3 in an uncrosslinked state interposed therebetween.
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Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6370967B1 (en) * 2017-06-28 2018-08-08 デクセリアルズ株式会社 Method for manufacturing image display device, photocurable resin composition, and light transmissive cured resin layer
JP6866881B2 (en) * 2017-08-08 2021-04-28 三菱ケミカル株式会社 Method for manufacturing photo-curable adhesive sheet laminate, photo-curable adhesive sheet laminate, and method for manufacturing image display panel laminate
JP6866880B2 (en) * 2017-08-08 2021-04-28 三菱ケミカル株式会社 Photo-curable adhesive sheet
CN111876091B (en) * 2017-08-08 2023-04-14 三菱化学株式会社 Photocurable adhesive sheet with release film
WO2019124333A1 (en) * 2017-12-18 2019-06-27 王子ホールディングス株式会社 Adhesive sheet and laminate manufacturing method
KR102024080B1 (en) * 2018-01-03 2019-09-24 주식회사 테이팩스 Composition for optical adhesive agent curable by ultraviolet, and an adhesive agent prepared from the composition, and a method for preparing the adhesive agent
CN108641620A (en) * 2018-03-28 2018-10-12 广州慧谷工程材料有限公司 A kind of pressure sensitive adhesive and its application process being used for imagery optical component, touch panel, display device
WO2020031991A1 (en) * 2018-08-06 2020-02-13 三菱ケミカル株式会社 Photocurable adhesive sheet, adhesive sheet laminate, laminate for image display device, and image display device
KR102024081B1 (en) * 2018-11-27 2019-09-24 주식회사 테이팩스 Composition for optical adhesive agent curable by light, an adhesive agent prepared from the composition, and a method for preparing the adhesive agent
KR102352953B1 (en) * 2018-12-14 2022-01-18 삼성에스디아이 주식회사 Adhesive film, optical member comprising the same and optical display apparatus comprising the same
KR102473023B1 (en) * 2019-11-01 2022-12-01 코제노벨머티얼리스코리아 주식회사 Pressure-sensitive adhesive film
KR20220103113A (en) * 2019-11-22 2022-07-21 미쯔비시 케미컬 주식회사 Adhesive sheet, laminated sheet, flexible image display device member, and flexible image display device
CN111518480B (en) * 2020-04-28 2021-07-16 常州百佳年代薄膜科技股份有限公司 Composite adhesive film, preparation method and equipment thereof, hot melt adhesive, adhesive and photovoltaic module
JP7276730B2 (en) * 2021-03-31 2023-05-18 大日本印刷株式会社 Transfer film, hard coat film, hard coat molding and method for producing the same
CN114149388B (en) * 2021-11-10 2023-05-02 广东红墙新材料股份有限公司 Prepolymer and derivative thereof, and preparation method and application thereof

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101195734A (en) * 2006-12-06 2008-06-11 日东电工株式会社 Removable pressure-sensitive adhesive composition and pressure-sensitive adhesive tape or sheet

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4825992B2 (en) * 1999-08-11 2011-11-30 綜研化学株式会社 Acrylic pressure-sensitive adhesive composition, method for producing pressure-sensitive adhesive tape using the composition, and pressure-sensitive adhesive tape
ATE400624T1 (en) * 2001-12-07 2008-07-15 3M Innovative Properties Co ACRYLIC PRESSURE SENSITIVE HOT HOT ADHESIVE AND USE THEREOF
JP4524320B2 (en) * 2008-08-11 2010-08-18 日東電工株式会社 Adhesive composition, adhesive layer, and adhesive sheet
TWI485214B (en) 2008-09-05 2015-05-21 Kyoritsu Chemical Co Ltd And a photohardenable resin composition for bonding an optical functional material
JP5716881B2 (en) 2008-10-04 2015-05-13 スリーボンドファインケミカル株式会社 Photocurable adhesive composition
JP5586497B2 (en) * 2010-04-21 2014-09-10 日東電工株式会社 Adhesive composition for optical member, adhesive layer, optical member provided with adhesive layer, image display device with optical member, and method of manufacturing image display device
JP2012007047A (en) * 2010-06-23 2012-01-12 Nitto Denko Corp Re-peeling off adhesive tape and manufacturing method therefor
EP3093832B1 (en) 2010-09-06 2018-01-31 Mitsubishi Chemical Corporation Image display device
JP5757809B2 (en) 2011-07-13 2015-08-05 綜研化学株式会社 Laminated body and touch panel having the laminated body
CN103748487B (en) * 2011-08-19 2017-05-17 Lg化学株式会社 Polarizing plate
KR101773756B1 (en) * 2012-01-18 2017-09-01 미쯔비시 케미컬 주식회사 Transparent double-sided adhesive sheet for image display device and image display device using same
JP5924324B2 (en) * 2012-10-05 2016-05-25 東亞合成株式会社 Adhesive composition and use thereof
CN104277720B (en) * 2013-07-08 2017-07-21 三星Sdi株式会社 Adhesive composition, binder film, polarization plates and display device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101195734A (en) * 2006-12-06 2008-06-11 日东电工株式会社 Removable pressure-sensitive adhesive composition and pressure-sensitive adhesive tape or sheet

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