TW202045674A - Adhesive sheet, adhesive sheet with release sheet, layered product, and production method for layered product - Google Patents

Abstract

The present invention provides an adhesive sheet that can exhibit superior adhesion to a base material and superior durability even under high-temperature and high-humidity conditions, and is less likely to wrinkle even in an application in which optical members having a large screen are attached together (an application in which the sheet having a relatively large area is applied) and thus has superior workability. The present invention is specifically an adhesive sheet having an adhesive agent layer containing an adhesive agent composition in a half-cured state, wherein the adhesive agent composition contains a crosslinkable acrylic copolymer A having an acidic component, a crosslinking agent B, a polyfunctional monomer C having two or more reactive double bonds in the molecule, and a photopolymerization initiator D, the crosslinkable acrylic copolymer A has a glass transition temperature (Tg) of -40 DEG C or higher, the adhesive agent layer is post-curable, and, when the adhesive agent layer is irradiated with actinic radiation in a cumulative light amount of 3000 mJ/cm2 for post-curing, the adhesive agent layer satisfies physical properties (1) and (2). Physical property (1): The elongation at break is 300% or more as measured in tensile testing at a rate of elongation of 10 mm/min. Physical property (2): The constant-load peel distances at i) 85 DEG C and a relative humidity of 85% and at ii) 85 DEG C and a relative humidity of less than 10% are each 50 mm or less under the following measurement conditions. (Measurement conditions) A region having a width of 25 mm and a length of 75 mm of the adhesive surface of the adhesive agent layer measuring 25 mm wide and 100 mm long is attached to an adherend, and is allowed to undergo post-curing. The adherend is fixed horizontally such that the non-attached region of the adhesive agent layer hangs downward in each of the environments: i) 85 DEG C and a relative humidity of 85%; and ii) 85 DEG C and a relative humidity of less than 10%. A load of 100 g is applied to an end in the length direction of the non-attached region of the adhesive agent layer for 5 minutes, during which the distance over which the attached region of the adhesive agent layer is released from the adherend is measured as respective constant-load peel distances at i) 85 DEG C and a relative humidity of 85% and at ii) 85 DEG C and a relative humidity of less than 10%.

Description

Adhesive sheet, adhesive sheet with release sheet, laminate, and method for manufacturing laminate

Invention field

The present invention relates to an adhesive sheet, an adhesive sheet with a release sheet, a laminate, and a method for manufacturing the laminate.

Background technique

In the past, display devices such as liquid crystal displays (LCD), and input devices such as touch panels used in combination with display devices have been widely used. In the manufacture of such display devices and input devices, transparent adhesive sheets are used for bonding optical components, and transparent adhesive sheets are also used for bonding between display devices and input devices.

The adhesive composition which forms the adhesive sheet for optical members can be manufactured by a well-known polymerization method. The polymerization method includes, for example, solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, etc. Among them, since it is easy to manufacture and can produce optically transparent adhesive sheets, solvent-based adhesives are widely used in adhesive layers. The adhesive sheet. Examples of the solvent-based adhesive include acrylic resin as the main component. Such an acrylic resin can be obtained by performing a polymerization reaction in a solvent in which an acrylic monomer has been dissolved in a solvent by a method called solution polymerization. In solution polymerization, as the polymerization progresses, the molecular weight of the polymer increases and the viscosity of the reaction solution increases. Therefore, the synthesis of a polymer with the necessary molecular weight in order to obtain the cohesive force necessary as an adhesive has technical limitations. Therefore, in order to ensure the cohesive force necessary for the adhesive, a crosslinking agent capable of reacting with acrylic resin, such as an isocyanate compound or an epoxy compound, is blended into the adhesive composition. This crosslinking agent reacts with acrylic resin over time, thereby building a crosslinking network and improving the cohesion of the adhesive layer.

In addition, as a method of forming an adhesive sheet for an optical member, a method of curing by two-stage hardening is sometimes used. The two-stage hardening is cross-linking by heat (or active energy rays) and then using the active The polymerization of energy rays (or heat). Such an adhesive sheet is formed of, for example, an adhesive composition having both thermosetting properties and active energy ray curability (hereinafter also referred to as "double-curing adhesive composition"), and therefore has thermosetting properties and active energy rays Hardening. Therefore, before bonding with the adherend, for example, only heat curing is performed to develop a hardness that is easy to handle. Then, after the adherend is bonded, the active energy rays are used to harden (called post Hardening or post-curing), which can firmly adhere to the adherend.

For example, Patent Document 1 describes an adhesive sheet containing an adhesive layer formed by semi-hardening the adhesive composition by heating, and the adhesive composition contains: a base polymer (A ), which contains a non-crosslinkable (meth)acrylate unit (a1) and an acrylic monomer unit (a2) with a crosslinkable functional group; monomer (B), which contains lauryl acrylate (b1); The crosslinking agent (C), which reacts with the base polymer (A) by heat; the polymerization initiator (D), which starts the polymerization reaction of the monomer (B) by irradiation of active energy rays; and the solvent ( E). In addition, Patent Document 2 discloses an adhesive sheet having at least one or more adhesive layers that can be cured by ultraviolet rays. Here, the storage elastic modulus G'(1 Hz) of the adhesive layer at a measurement temperature of 20°C and a frequency of 1 Hz after being cured by ultraviolet rays is 1×10 ⁴ to 1×10 ⁶ Pa. Prior Art Document Patent Document

Patent Document 1: Japanese Patent Application Publication No. 2016-084391 Patent Document 2: JP 2012-031059 A

Summary of the invention Problems to be solved by the invention

However, when the inventors studied the properties of the adhesive sheets described in Patent Documents 1 and 2, they found that the adhesion and durability of the substrate may be insufficient. Especially under high temperature and high humidity conditions, it may not be sufficient. Obtain substrate adhesion and durability. In addition, the workability after curing is also insufficient. In order to improve the workability, an attempt has been made to increase the hardness of the cured adhesive layer. However, if the hardness is excessively increased, it is likely to occur in applications such as lamination of large-screen optical components. Wrinkles, especially when one of the attached optical members is a cellulose triacetate film, is more likely to produce wrinkles, so there is still room for improvement.

Therefore, in order to solve the problems of this conventional technology, the inventors have studied for the purpose of providing an adhesive sheet that can exhibit excellent substrate adhesion and durability even under high temperature and high humidity conditions. , It is not easy to produce wrinkles even in applications such as laminating large-screen optical components (construction applications in a large area), and has excellent workability. Means to solve the problem

In order to achieve the above-mentioned problem, the inventors have carefully studied and found that the above-mentioned object can be achieved by the following adhesive sheet, and thus completed the present invention, namely: an adhesive sheet having a semi-hardened state of the adhesive composition The adhesive layer, and the aforementioned adhesive composition contains a specific crosslinkable acrylic copolymer A with an acid component, a crosslinking agent B, a multifunctional monomer C having two or more reactive double bonds in the molecule, and photopolymerization Initiator D satisfies specific physical property groups at the same time.

That is, the present invention relates to the following adhesive sheets, adhesive sheets with release sheets, laminates, and methods for manufacturing laminates. 1. An adhesive sheet having an adhesive layer having an adhesive composition in a semi-hardened state, the aforementioned adhesive composition containing a crosslinkable acrylic copolymer A having an acid component, a crosslinking agent B, The polyfunctional monomer C and photopolymerization initiator D with 2 or more reactive double bonds, and the glass transition temperature (Tg) of the aforementioned crosslinkable acrylic copolymer A is -40°C or more, and the aforementioned adhesive layer has post-curing When the adhesive layer is irradiated with active energy rays to form 3000mJ/cm ² of accumulated light and then cured, the adhesive layer satisfies the following physical properties (1) and (2); Physical properties (1): stretching speed The elongation at break measured by the tensile test at 10mm/min is more than 300%; physical properties (2): measured under the following measuring conditions at i) 85℃, relative humidity 85% and ii) 85℃, relative humidity less than 10 The peeling distance of each fixed load under% is 50mm or less: (Measurement conditions) The area of 25mm in width and 75mm in length on the adhesive surface of an adhesive layer with a width of 25mm and a length of 100mm is attached to the adherend, and then cured. Under i) 85℃, relative humidity 85% and ii) 85℃, relative humidity less than 10%, fix the adherend in the horizontal direction by hanging the non-laminated area of the adhesive layer downward. A load of 100g was applied to the longitudinal end of the non-bonding area of the adhesive layer for 5 minutes, and the distance between the bonding area of the adhesive layer and the adherend was measured, as i) 85°C, relative humidity 85% and ii) The peeling distance of each constant load under 85℃ and relative humidity less than 10%. 2. The adhesive sheet according to the above item 1, wherein the aforementioned adhesive composition contains a monofunctional monomer E having one reactive double bond in the molecule. 3. The adhesive sheet of item 2 above, wherein the content of the monofunctional monomer E is 1 to 20 parts by mass relative to 100 parts by mass of the crosslinkable acrylic copolymer A. 4. The adhesive sheet according to any one of the above items 1 to 3, wherein the content of the multifunctional monomer C is 1 to 20 parts by mass relative to 100 parts by mass of the crosslinkable acrylic copolymer A. 5. The adhesive sheet according to any one of the above items 1 to 4, wherein the acid value of the aforementioned crosslinkable acrylic copolymer A is 1 mgKOH/g or more. 6. The adhesive sheet according to any one of the above items 1 to 5, wherein the difference between the gel fraction of the adhesive layer in the semi-cured state and the gel fraction after post-curing is 15% or more. 7. An adhesive sheet with a release sheet, which has a pair of release sheets with different peeling forces on both sides of the adhesive sheet of any one of items 1 to 6 above. 8. A laminate having the adhesive sheet of any one of the above items 1 to 6 and an adherend provided on at least one side of the adhesive sheet, wherein the adhesive layer of the adhesive sheet is irradiated with active energy The thread then hardens. 9. A method for manufacturing a laminate, which sequentially includes: step 1, applying a volume layer to be adhered to at least one side of the adhesive sheet of any one of items 1 to 6; and step 2, by comparing the foregoing The adhesive layer of the adhesive sheet is irradiated with active energy rays to harden the aforementioned adhesive layer. Invention effect

According to the present invention, an adhesive sheet can be produced, which can exhibit excellent substrate adhesion and durability even under high temperature and high humidity conditions, and is not easy to produce in applications such as laminating large-screen optical components. Wrinkles and excellent workability.

The form used to implement the invention

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on representative embodiments or specific examples, and the present invention is not limited to such embodiments. In addition, in this specification, the numerical range indicated by "~" means the range which includes the numerical value described before and after "~" as the lower limit and the upper limit.

In addition, in this specification, "(meth)acrylate" means both or either of acrylate and methacrylate, and "(meth)acrylic" means both or either of acrylic acid and methacrylic acid.

In addition, in this specification, "monomer" and "monomer" are synonymous, and "polymer" and "polymer" are synonymous.

<Adhesive sheet> The adhesive sheet of the present invention has an adhesive layer in which the adhesive composition has been semi-hardened. The adhesive composition contains a crosslinkable acrylic copolymer A having an acid component, a crosslinking agent B, a multifunctional monomer C having two or more reactive double bonds in the molecule, and a photopolymerization initiator D, and the aforementioned crosslinking The glass transition temperature (Tg) of the acrylic copolymer A is -40°C or higher. The adhesive layer has post-curing properties. When the accumulated light amount constitutes 3000mJ/cm ^2, the adhesive layer is irradiated with active energy rays and then cured When the aforementioned adhesive layer satisfies the following physical properties (1) and (2); Physical properties (1): The breaking elongation measured by the tensile test at a tensile speed of 10 mm/min is more than 300%; Physical properties (2): Use The following measurement conditions are measured at i) 85°C, relative humidity 85%, and ii) 85°C, relative humidity less than 10%, each fixed load peeling distance is less than 50mm: (Measurement conditions) The width of 25mm, length of 100mm The area of 25mm in width and 75mm in length on the adhesive surface of the adhesive layer is attached to the adherend, and then cured. Under i) 85℃, relative humidity 85% and ii) 85℃, relative humidity less than 10%, fix the adherend in the horizontal direction by hanging the non-laminated area of the adhesive layer downward. A load of 100g was applied to the longitudinal end of the non-bonding area of the adhesive layer for 5 minutes, and the distance between the bonding area of the adhesive layer and the adherend was measured, as i) 85°C, relative humidity 85% and ii) The peeling distance of each constant load under 85℃ and relative humidity less than 10%. In addition, the fixed load peeling distance under the conditions of i) shows the high temperature and high humidity substrate adhesion, and the fixed load peeling distance under the conditions shows the high temperature substrate adhesion.

The adhesive sheet of the present invention having the above-mentioned structure can exhibit excellent substrate adhesion and durability even under high temperature and high humidity conditions, and at the same time, it is not prone to wrinkles in applications such as laminating large-screen optical members , Processability is also excellent. Such effects of the present invention can be obtained particularly by the following: the crosslinkable acrylic copolymer A contained in the adhesive composition has an acid component, and the glass transition temperature (Tg) is -40°C or higher, and satisfies the above Physical properties (1) and (2) conditions. We believe that especially by making the crosslinkable acrylic copolymer A have an acid component, the uniformity of the crosslinked structure formed by the crosslinkable acrylic copolymer A is improved, thereby improving the durability of the adhesive sheet. In addition, we believe that by making the crosslinkable acrylic copolymer A have an acid component, the adhesion between the adhesive sheet and the adherend (substrate adhesion) is improved, thereby also improving the durability of the adhesive sheet Sex. Furthermore, by satisfying the above-mentioned physical properties (1), the post-curing adhesive layer has an appropriate hardness, even when cellulose triacetate is used, it is also used in applications such as bonding large-screen optical members. Wrinkles are less likely to occur, and processability is also excellent.

In this specification, the durability of the adhesive sheet can be evaluated by the following method. First, a cellulose triacetate film is attached to one side of the adhesive sheet, and a polycarbonate plate is attached to the other side, and the light is irradiated from the side of the cellulose triacetate film to form 3000mJ/cm ² The active energy rays harden the adhesive layer. Then, the adhesive sheet was allowed to stand at i) 85° C., 85% relative humidity and ii) 85° C. and relative humidity less than 10% for 240 hours. Then, by observing the adhesive sheet, when floating or peeling from the polycarbonate plate and/or cellulose triacetate film can be suppressed, it is judged that the durability is excellent. In addition, the judgment of i) condition shows the durability of high temperature and high humidity, and the judgment of condition ii) shows the durability of high temperature.

Furthermore, in the adhesive sheet of the present invention, it is possible to suppress stickiness on the end surface after hardening. For example, it is possible to prevent the adhesive from adhering to the punching knife during punching, or the deformation of the adhesive layer accompanying this. Furthermore, after the adhesive sheet of the present invention is post-hardened and punched to a desired size, when cutting for the purpose of adjusting the end face, deformation, exudation or peeling of the adhesive layer will not occur. The sex is also excellent.

＜The structure of the adhesive sheet＞ The adhesive sheet of the present invention has an adhesive layer. The adhesive sheet may be a single-layer adhesive sheet composed of only an adhesive layer. In addition, the adhesive sheet may be a single-sided adhesive sheet with a substrate (preferably a transparent substrate) on one side, or a double-sided adhesive sheet. Examples of adhesive sheets include: single-layer adhesive sheets composed of adhesive layers; multilayer adhesive sheets laminated with multiple adhesive layers; multilayer adhesive sheets with other adhesive layers laminated between the adhesive layer and the adhesive layer Material; a multilayer adhesive sheet with a support laminated between the adhesive layer and the adhesive layer; a multilayer adhesive sheet with an adhesive layer laminated on one side of the support and another adhesive layer laminated on the other side. When the double-sided adhesive sheet has a support, it is preferable to use a transparent support for the support. The support may be the same as the transparent substrate, and a general film used in the optical field may be used. Such a double-sided pressure-sensitive adhesive sheet is also excellent in transparency as the entire pressure-sensitive adhesive sheet, and therefore can be suitably used for bonding optical members.

When the adhesive sheet of the present invention is a single-sided adhesive sheet, as shown in FIG. 1, it may have a structure in which a transparent substrate 12a is provided on one side of the adhesive layer 11. At this time, the other side of the adhesive layer 11 is preferably covered by the release sheet 12b. When using an adhesive sheet, it is preferable to peel off the peeling sheet 12b, and stick the adhesive layer 11 close to the desired adherend, and then irradiate active energy rays to perform post-curing. As the transparent substrate, a general film used in the optical field such as a polyethylene terephthalate film, an acrylic film, a polycarbonate film, a cellulose triacetate film, or a cycloolefin polymer film can be used. In addition, an easy-to-bond layer can also be provided on the adhesive layer side of the transparent substrates. Furthermore, functional layers such as a hard coat layer, an anti-reflection layer, an anti-fouling layer, or an ultraviolet absorbing layer may be provided on the opposite side of the transparent substrate from the adhesive layer.

The present invention also relates to an adhesive sheet with a release sheet, which is provided with release sheets on both sides of the adhesive sheet. When the adhesive sheet of the present invention has release sheets on both sides, as shown in FIG. 1, it is preferable to have release sheets 12a and 12b on both sides of the adhesive layer 11.

Examples of the release sheet include: a release laminate sheet having a base material for a release sheet and a release agent layer provided on one side of the base material for a release sheet; or a polyethylene film or polymer as a low-polarity base material Polyolefin films such as propylene films.

Among the peelable laminated sheets, paper or polymer films can be used as the base material for the peelable sheet. As the release agent constituting the release agent layer, for example, a general addition type or condensation type silicone release agent or a long-chain alkyl group-containing compound can be used. It is especially suitable to use an addition type silicone release agent with high reactivity.

Specific examples of the silicone-based release agent include BY24-4527 and SD-7220 manufactured by Dow Corning Toray Silicone; or KS-3600, KS-774, X62-2600 manufactured by Shin-Etsu Chemical Industries, etc. In addition, the silicone-based release agent should preferably contain silicone resin, which is an organic compound having SiO ₂ units and (CH ₃ ) ₃ SiO _1/2 units or CH ₂ =CH(CH ₃ )SiO _1/2 units. Silicon compound. Specific examples of silicone resins include BY24-843, SD-7292, SHR-1404 manufactured by Dow Corning Toray Silicone, etc.; or KS-3800, X92-183 manufactured by Shin-Etsu Chemical Co., Ltd., etc.

Commercial products can also be used for the peelable laminated sheet. For example, it can be listed: Teijin DuPont Films manufactured by Teijin DuPont Films is a polyethylene terephthalate film that has undergone mold release processing; or Teijin DuPont Films is manufactured by Teijin DuPont Films is a polyethylene terephthalate film that has undergone mold release processing. Light isolation film.

When the adhesive sheet of the present invention is a double-sided adhesive sheet, it is preferable to have a pair of peeling sheets with different peeling forces. That is, in order to make the peeling sheet easy to peel, it is preferable to make the peelability of the peeling sheet 12a and the peeling sheet 12b different. If the releasability from one is different from the releasability from the other, it is easy to constitute that only the release sheet with higher releasability will peel off first. At this time, the peelability of the peeling sheet 12a and the peeling sheet 12b can be adjusted in accordance with the bonding method or bonding order.

Moreover, the present invention also relates to an adhesive sheet with a transparent film, which has a transparent film on at least one side of the adhesive sheet. In this case, the transparent film is preferably at least one selected from polyethylene terephthalate film, acrylic film, polycarbonate film, cellulose triacetate film, and cycloolefin polymer film. The adhesive sheet with transparent film may also be a sheet in which a transparent film/adhesive sheet/release sheet has been laminated in this order.

＜Adhesive layer＞ The adhesive sheet of the present invention has an adhesive layer in which the adhesive composition is in a semi-hardened state, and the adhesive layer has post-curing properties.

Here, in this specification, when the active energy rays are irradiated under the following conditions, whereby the gel fraction of the adhesive layer can be increased by more than 10% by mass, the adhesive layer before irradiation is in a semi-cured state. In this case, on both sides of the adhesive layers laminated to an optical transparent PET separator to accumulated light quantity constituting 3000mJ / cm Embodiment ² of from one optical transparent PET separator irradiated with active energy ray (high pressure mercury lamp or a metal halide light).

Among them, the gel fraction of the adhesive layer in the semi-hardened state is preferably 10% by mass or more and less than 75% by mass, preferably 12% by mass or more and less than 75% by mass, and more preferably 15 to 70% by mass. Furthermore, the gel fraction of the adhesive layer after post-curing is preferably 60-100% by mass, preferably 65-100% by mass, and more preferably 70-100% by mass. In addition, the difference between the gel fraction of the adhesive layer in the semi-cured state and the gel fraction after post-curing is preferably 15% or more, more preferably 20% or more.

The gel fraction of the adhesive layer is a value measured by the following method. First, about 0.1 g of an adhesive sheet (adhesive layer) was collected in a sample bottle, 30 ml of ethyl acetate was added and shaken for 24 hours. Then, the contents of the sample bottle were filtered out with a stainless steel wire mesh of 150 mesh, and the residue on the wire mesh was dried at 100°C for 1 hour, and the dry mass (g) was measured. Using the following formula 1, the gel fraction was calculated from the obtained dry mass. Gel fraction (mass%)=(dry mass/collected mass of adhesive layer)×100...Equation 1

In this manual, the "semi-hardened state" is preferably the state after thermal hardening. In addition, it is more desirable to irradiate the active energy rays later to perform "post-curing". That is, the adhesive layer of the adhesive sheet of the present invention is preferably such that the adhesive composition is thermally hardened to form a semi-cured state, and it is preferable to have active energy ray curability.

When the adhesive layer is irradiated with active energy rays to form 3000mJ/cm ² of accumulated light quantity and then cured, the adhesive layer satisfies the following physical properties (1) and (2); Physical properties (1): stretching speed of 10mm/min The elongation at break measured in the tensile test is more than 300%; Physical properties (2): measured under the following measuring conditions at i) 85℃, relative humidity 85% and ii) 85℃, relative humidity less than 10%. The fixed load peeling distance is less than 50mm: (Measurement conditions) The area of 25mm wide and 75mm long on the adhesive surface of the adhesive layer with a width of 25mm and a length of 100mm is attached to the adherend, and then cured. Under i) 85℃, relative humidity 85% and ii) 85℃, relative humidity less than 10%, fix the adherend in the horizontal direction by hanging the non-laminated area of the adhesive layer downward. A load of 100g was applied to the longitudinal end of the non-bonding area of the adhesive layer for 5 minutes, and the distance between the bonding area of the adhesive layer and the adherend was measured, as i) 85°C, relative humidity 85% and ii) The peeling distance of each constant load under 85℃ and relative humidity less than 10%.

The above-mentioned physical property (1) (elongation at break) may be 300% or more, but it is preferably 320% or more, preferably 350% or more, and more preferably 500% or more. In addition, the upper limit of the elongation at break is not particularly limited, for example, 1000%. Here, the elongation at break is measured in accordance with JIS K 7161-1. At this time, the stretching speed was set to 10 mm/min, and the measurement was performed at 23° C. and a relative humidity of 50%. In addition, the measurement sample used the following: an adhesive layer having a thickness of 25 μm, a width of 60 mm, and a length of 200 mm was rounded in the longitudinal direction and processed into a cylindrical shape with a cross-sectional area of 5 mm ² and a height of 60 mm. Stretch it so that the distance between the chucks is 30 mm, and set the elongation when the sample is broken as the elongation at break. In addition, as a measuring device, for example, AUTOGRAPH AGS-X manufactured by Shimadzu Corporation can be used.

For the measurement of the above-mentioned physical property (2) (fixed load peeling distance), in detail, first, a test piece for measurement is produced by the following method. Using a hand roller, a cellulose triacetate film (manufactured by FUJIFILM, FUJITAC TD60UL, thickness 60μm) was laminated on one surface of the adhesive layer to produce a laminated film. The laminated film was cut into a size of 25mm in width and 100mm in length. Next, using a 2kg pressure bonding roller, the other side of the adhesive layer with a width of 25mm and a length of 100mm was applied on the adhesive surface with a width of 25mm and a length of 75mm. (Polycarbonate board with hard coating: manufactured by Mitsubishi Gas Chemical Corporation, IUPILON MR58, thickness 1mm) on the hard-coated side. In this state, it was kept in an autoclave at 40°C and 5 atmospheres for 30 minutes to adhere to the adherend.

In addition, in the above-mentioned measurement conditions, when post-curing was performed, ultraviolet rays were irradiated from the cellulose triacetate film side of the test piece for measurement so that the accumulated light amount constitutes 3000 mJ/cm ² .

Then, after placing for 24 hours under i) 85℃, relative humidity 85% and ii) 85℃, relative humidity less than 10%, respectively, at i) 85℃, relative humidity 85% and ii) 85℃, relative humidity Under an environment of less than 10%, hang a weight 34 of 100g on the lengthwise end of the non-laminated area (width 25mm, length 25mm) of the laminated film as shown in Figure 4, in a plane relative to the adherend 32. Apply a load of 100g in the direction of 90° and leave it for 5 minutes in this state. The length L (the peeling distance under a constant load) at the point where the laminated film has been peeled off is measured.

Using the above measurement conditions, i) the peeling distance under a constant load at 85°C and 85% relative humidity is 50mm or less, preferably 45mm or less, preferably 40mm or less, more preferably 35mm or less, and particularly preferably 30mm or less. Moreover, the peeling distance under a constant load at ii) 85°C and a relative humidity of less than 10% is 50 mm or less, and preferably 45 mm or less, preferably 40 mm or less, more preferably 35 mm or less, and particularly preferably 30 mm or less. In addition, the peeling distance under constant load at i) 85°C, relative humidity 85% and ii) 85°C and relative humidity less than 10% can also be 0 mm respectively.

When the adhesive layer is irradiated with active energy rays to form 3000 mJ/cm ² of integrated light and then cured, the adhesive layer preferably satisfies the following physical properties (3) in addition to the above physical properties (1) and (2).

Physical properties (3): The probe viscosity value is 1.0N/5mmφ or less.

(Measurement condition of probe viscosity value) Measuring machine: NS probe viscosity tester (manufactured by NICHIBAN) Probe diameter: 5mmφ Probe substrate: stainless steel surface finishing AA#400 grinding mirror Weight: 19.6±0.2g (made of brass) Probe moving speed: 1.0cm/sec Residence time: 1 second

The probe viscosity value of the adhesive layer after the above post-curing is more preferably 1.0N/5mmφ or less, and more preferably 0.5N/5mmφ or less. In addition, the lower limit of the probe viscosity value is not particularly limited. For example, it is more preferably 0.1N/5mmφ or more, and particularly preferably 0.01N/5mmφ or more. By setting the probe viscosity value of the post-cured adhesive layer within the above range, workability is excellent and workability becomes good.

The thickness of the adhesive layer can be appropriately set according to the application, and is not particularly limited, and is preferably 5 to 150 μm, more preferably 8 to 100 μm, and particularly preferably 10 to 80 μm. By setting the thickness of the adhesive layer within the above range, the exudation or stickiness of the adhesive can be suppressed, thereby improving the workability. Furthermore, by setting the thickness of the adhesive layer within the above range, the production of the double-sided adhesive sheet becomes easy.

＜Adhesive composition＞ The above-mentioned adhesive layer is one that has made the adhesive composition in a semi-hardened state. The adhesive composition used in the present invention is a double hardening type adhesive composition. The adhesive composition contains: a cross-linkable acrylic copolymer A with an acid component (however, the glass transition temperature (Tg) is -40°C or higher); a cross-linking agent B; a molecule having two or more reactive double bonds Multifunctional monomer C; and photopolymerization initiator D.

(Crosslinkable acrylic polymer A) The crosslinkable acrylic polymer A is not particularly limited as long as it has an acrylic monomer unit containing an acid component and has a glass transition temperature (Tg) of -40°C or higher. For example, it is preferably a non-crosslinkable (A Yl) Acrylate unit (a1) and acrylic monomer unit (a2) having an acid component-containing crosslinkable functional group are copolymerized. The cross-linkable acrylic polymer A preferably has transparency that does not reduce the visibility of the display device. In addition, in this specification and the scope of patent application, "unit" is a repeating unit (monomer unit) constituting a polymer.

The non-crosslinkable (meth)acrylate unit (a1) is a repeating unit derived from an alkyl (meth)acrylate. Examples of alkyl (meth)acrylates include: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, (meth)acrylic acid N-butyl ester, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate Ester, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, (meth) ) Isodecyl acrylate, n-undecyl (meth)acrylate, n-dodecyl (meth)acrylate, stearyl (meth)acrylate, methoxyethyl (meth)acrylate, Ethoxy ethyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, etc. These may be used individually by 1 type, and may use 2 or more types together.

Among the above-mentioned alkyl (meth)acrylates, in view of improving adhesion, they are preferably selected from methyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate At least one of the esters.

In this invention, the crosslinkable functional group which a crosslinkable acrylic polymer has contains an acid component. Here, the crosslinkable functional group constituting the acid component is preferably a carboxyl group or a group derived from a carboxyl group, or a sulfonic acid group or a group derived from a sulfonic acid group, and particularly preferably a carboxyl group. That is, the acrylic monomer unit (a2) having an acid component-containing crosslinkable functional group is preferably a carboxyl group-containing monomer unit. Examples of carboxyl group-containing monomer units include acrylic acid and methacrylic acid.

Moreover, the crosslinkable functional group which the crosslinkable acrylic polymer A has may have functional groups other than the crosslinkable functional group which comprises an acid component. Examples of other functional groups include a hydroxyl group, an amino group, an amide group, a glycidyl group, or an isocyanate group.

The content of the acrylic monomer unit (a2) having a crosslinkable functional group containing an acid component in the crosslinkable acrylic polymer A is preferably 0.01-40% by mass, more preferably 0.5-35% by mass. If the content of the acrylic monomer unit (a2) having a crosslinkable functional group containing an acid component is more than the lower limit of the above range, the crosslinkability necessary to maintain the semi-cured state can be fully exhibited. If it is below the upper limit of the above range, it is easy to maintain the necessary adhesiveness.

The crosslinkable acrylic polymer A may have other monomer units as needed. Other monomers may be copolymerized with the above-mentioned acrylic monomers, and examples thereof include (meth)acrylonitrile, vinyl acetate, styrene, vinyl chloride, vinylpyrrolidone, vinylpyridine, and the like. The content of other monomer units in the crosslinkable acrylic polymer is preferably 20% by mass or less, more preferably 15% by mass or less.

The glass transition temperature (Tg) of the crosslinkable acrylic polymer A may be -40°C or higher, preferably -38°C or higher, and more preferably -35°C or higher. The upper limit of the glass transition temperature (Tg) is not limited, and for example, it may be 0°C or less. By setting the glass transition temperature (Tg) of the crosslinkable acrylic polymer A within the above range, the workability of the adhesive sheet can be more effectively improved.

The specific glass transition temperature can use literature values, or the value of the glass transition temperature of the crosslinkable acrylic polymer A measured by DSC (differential scanning calorimetry).

The weight average molecular weight of the crosslinkable acrylic polymer A is preferably 100,000 to 2 million, and more preferably 200,000 to 1.5 million. If the weight average molecular weight is within the above range, the semi-cured state of the adhesive layer is easily maintained, and the hardness after post-curing is easily generated, and the workability is excellent. In addition, the weight average molecular weight of crosslinkable acrylic polymer A is the value before crosslinking by a crosslinking agent. The weight average molecular weight is measured by particle size sieve analysis chromatography (SEC), and is a value obtained on the basis of polystyrene. As the crosslinkable acrylic polymer, a commercially available product can be used, or one synthesized by a known method can also be used.

The acid value of the crosslinkable acrylic polymer A is preferably 1 mgKOH/g or more, preferably 2 mgKOH/g or more, and more preferably 3 mgKOH/g or more. In addition, the acid value of the crosslinkable acrylic polymer A is preferably 200 mgKOH/g or less. In addition, in the present invention, the acid value of the adhesive layer formed of the adhesive composition is also preferably within the above range.

The acid value of the crosslinkable acrylic polymer A is calculated by the following method. First, in a 100ml Erlenmeyer flask, accurately weighed with a precision balance to make the solid content of the sample crosslinkable acrylic polymer A constitute about 2g, and add toluene/2-propanol/water=5/5/ 10 ml of a mixed solvent of 0.5 (weight ratio) was dissolved. Next, add 1 to 3 drops of p-naphtholbenzene solution as an indicator to the container, and stir thoroughly until the sample becomes uniform. Titrate it with 0.1N potassium hydroxide-2-propanol solution, and set the end point of neutralization when the light red of the indicator has continued for 30 seconds. From this result, the value obtained using the following formula (1) was taken as the acid value of the sample.

Acid value (mgKOH/g)=[cKOH×(V1-V0)×5.611]/S (1) In the formula (1), cKOH is the molar concentration (mol/L) of the 0.1N potassium hydroxide-2-propanol solution, and V1 is the 0.1mol/L potassium hydroxide-2-propanol solution required for the titration of the sample Volume (mL), V0 is the volume (mL) of 0.1 mol/L potassium hydroxide-2-propanol solution required for the titration of the blank test, and S is the sample collection volume (g).

(Crosslinking agent B) The adhesive composition contains a crosslinking agent. The crosslinking agent can be appropriately selected in consideration of the reactivity with the crosslinkable functional group of the crosslinkable acrylic polymer A. For example, it can be selected from known crosslinking agents such as isocyanate compounds, epoxy compounds, oxazoline compounds, aziridine compounds, metal chelate compounds, and butylated melamine compounds. Among them, it is preferable to use an epoxy compound in view of easily crosslinking carboxyl group-containing acrylate. That is, the crosslinking agent is preferably an epoxy compound having two or more functions.

The epoxy compound includes, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and glycerol bicyclic ring Oxypropyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, tetraglycidyl diamine, 1,3-bis(N,N-diglycidyl) Glycidylaminomethyl) cyclohexane, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether Ether etc.

The content of the cross-linking agent in the adhesive composition can be appropriately selected according to the desired adhesiveness, etc., relative to 100 parts by mass of the cross-linkable acrylic polymer, it is preferably 0.01-5 parts by mass, more preferably 0.01-3 parts by mass . By setting the content of the crosslinking agent within the above-mentioned range, the adhesion to the substrate can be improved, and the processability can be further improved. In addition, the crosslinking agent may be used alone or in combination of two or more types. When two or more types are used in combination, the total mass is preferably within the above range.

(Multifunctional monomer C) The adhesive composition contains a multifunctional monomer C having two or more reactive double bonds in the molecule.

Examples of the multifunctional monomer C include ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4 -Butanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,6-hexanediol diacrylate, polybutylene glycol di(meth)acrylate, Neopentyl glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, bisphenol A diepoxy One of polyols such as diacrylate of propyl ether, trimethylolpropane tri(meth)acrylate, neopentaerythritol tri(meth)acrylate, neopentaerythritol tetra(meth)acrylate, etc. Base) Acrylic esters, vinyl methacrylate, etc.

The multifunctional monomer C has two or more reactive double bonds. Among them, the multifunctional monomer preferably has two or more and less than 5 reactive double bonds, and more preferably has two or more and less than 4.

Commercially available products can be used for the polyfunctional monomer C. Examples of commercially available products include: trifunctional monomer M310 (trimethylolpropane PO modified triacrylate) or trifunctional monomer M321 (trimethylolpropane propylene oxide modified triacrylate) manufactured by Toagosei Ester), the bifunctional monomer M211B (bisphenol A EO modified diacrylate) manufactured by Toagosei.

The multifunctional monomer C may also have a bisphenol skeleton in one molecule. By using a multifunctional monomer with a bisphenol skeleton in one molecule, the hardness of the adhesive layer after hardening can be more effectively increased, and the workability of the adhesive sheet can be easily improved.

Examples of such multifunctional monomer C include: the diacrylate of bisphenol A diglycidyl ether, the diacrylate of propoxylated bisphenol A, the diacrylate of bisphenol F diglycidyl ether Wait.

The glass transition temperature (Tg) when the polyfunctional monomer C is made into a homopolymer is preferably 30°C or higher, more preferably 50°C or higher. The glass transition temperature (Tg) when the polyfunctional monomer is a homopolymer can be, for example, 300°C or lower. The glass transition temperature (Tg) when the polyfunctional monomer C is made into a homopolymer can be more effectively improved in the workability of the adhesive sheet by setting it within the above range.

In addition, the glass transition temperature in this specification is the glass transition temperature when the polyfunctional monomer C is made into a homopolymer. The specific glass transition temperature can use literature values, or it can be measured by DSC (differential scanning calorimetry) after making the polyfunctional monomer C into a homopolymer with a weight average molecular weight of 10,000 or more. The value of the glass transition temperature of the object.

The content of the multifunctional monomer C in the adhesive composition is preferably 1-20 parts by mass relative to 100 parts by mass of the crosslinkable acrylic polymer A, preferably 1-15 parts by mass, and more preferably 1-10 parts by mass. The above-mentioned polyfunctional monomer C may be used alone or in combination of two or more types. When two or more types are used in combination, the total mass is preferably within the above range. By setting the content of the multifunctional monomer C within the above range, the aforementioned physical properties (1) to (3) can be easily achieved, and the high temperature and high humidity durability can be improved. Furthermore, by setting the content of the multifunctional monomer C within the above range, the hardness of the post-curing adhesive layer can be more effectively increased, and the workability of the adhesive sheet can be improved.

(Photopolymerization initiator D) The adhesive composition contains a photopolymerization initiator D. The photopolymerization initiator is preferably one that starts polymerization of the crosslinkable acrylic polymer or multifunctional monomer by irradiation with active energy rays. As the photopolymerization initiator E, a known photopolymerization initiator can be used.

Here, the so-called "active energy rays" refer to electromagnetic waves or charged particle beams that have energy quantum, such as ultraviolet rays, electron beams, visible rays, X-rays, ion beams, etc. Among them, from the viewpoint of versatility, ultraviolet light or electron beam is preferable, and ultraviolet light is particularly preferable.

The photopolymerization initiator D includes, for example, acetophenone-based initiators, benzoin ether-based initiators, benzophenone-based initiators, hydroxyalkylphenone-based initiators, thioxanthone-based initiators, and amine-based initiators , Phosphine oxide-based initiators, etc.

Specific examples of the acetophenone-based initiator include diethoxyacetophenone, benzil dimethyl ketal, and the like.

Specific examples of the benzoin ether-based initiator include benzoin and benzoin methyl ether.

Specific examples of the benzophenone-based initiator include benzophenone, methyl phthalate and the like.

Specific examples of the hydroxyalkyl phenone-based initiator include 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF Japan, commercially available as IRGACURE 184) and the like.

Specific examples of the thioxanthone-based initiator include 2-isopropylthioxanthone and 2,4-dimethylthioxanthone.

Specific examples of the amine-based initiator include triethanolamine and ethyl 4-dimethylbenzoate.

Specific examples of the phosphine oxide-based initiator include phenylbis(2,4,6-trimethylbenzyl) phosphine oxide (manufactured by BASF Corporation in Japan, and marketed as IRGACURE 819).

The content of the photopolymerization initiator D in the adhesive composition is preferably 0.05-10 parts by mass relative to 100 parts by mass of the crosslinkable acrylic polymer, and more preferably 0.1-5 parts by mass. If it is more than the above lower limit, post-curing can be used to adjust the hardness to a desired hardness, and the molecular weight after post-curing can be set in an appropriate range, so an adhesive sheet with excellent workability can be obtained. The photopolymerization initiator D may be used alone or in combination of two or more types. When two or more types are used in combination, the total mass is preferably within the above range.

(Monofunctional monomer E) In addition to the above-mentioned essential components, the adhesive composition may contain a monofunctional monomer E having one reactive double bond in the molecule.

Examples of the monofunctional monomer E include: isobornyl acrylate, isostearyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, benzyl methacrylate, N-acryloyloxy Ethyl hexahydrophthalimide, acrylamide, N,N-dimethyl acrylamide, N,N-diethyl acrylamide, acryl morpholine, vinyl pyrrolidone, etc. Among them, the monofunctional monomer is preferably an alkyl (meth)acrylate, and is preferably at least one selected from isobornyl acrylate and isostearyl acrylate, more preferably isobornyl acrylate. Examples of commercially available products of the monofunctional monomer E include DEAA manufactured by KJ Chemical Co., Ltd., IBXA manufactured by Osaka Organic Chemical Industry Co., Ltd., and the like.

The glass transition temperature (Tg) when the monofunctional monomer E is made into a homopolymer is preferably 50°C or more and less than 200°C, more preferably 55°C or more and less than 180°C.

The content of the monofunctional monomer E is preferably 1 to 20 parts by mass relative to 100 parts by mass of the crosslinkable acrylic polymer A, preferably 1 to 15 parts by mass, and more preferably 1 to 10 parts by mass. The monofunctional monomer E may be used alone or in combination of two or more types. When two or more types are used in combination, the total mass is preferably within the above range.

(Solvent) The adhesive composition may also contain a solvent. At this time, the solvent is used to improve the coating suitability of the adhesive composition. Examples of the solvent include hydrocarbons such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; dichloromethane, trichloroethane, trichloroethylene, and tetrachloroethylene. Halogenated hydrocarbons such as vinyl chloride and dichloropropane; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and diacetone alcohol; diethyl ether, diisopropyl ether, and diethyl ether , Tetrahydrofuran and other ethers; acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone and other ketones; methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, acetic acid Esters such as amyl ester and ethyl butyrate; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Polyols such as propylene glycol monomethyl ether acetate and their derivatives.

The content of the solvent in the adhesive composition is not particularly limited. It is preferably 25 to 500 parts by mass, and more preferably 30 to 400 parts by mass relative to 100 parts by mass of the crosslinkable acrylic polymer A.

Furthermore, the content of the solvent is preferably 10 to 90% by mass, and more preferably 20 to 80% by mass relative to the total mass of the adhesive composition. The solvent may be used alone or in combination of two or more types. When two or more types are used in combination, the total mass is preferably within the above range.

(Other ingredients) The adhesive composition may contain components other than the above within a range that does not impair the effects of the present invention. Other components can be exemplified as well-known components as additives for adhesives. For example, if necessary, it can be selected from plasticizers, antioxidants, metal corrosion inhibitors, tackifiers, silane coupling agents, ultraviolet absorbers, hindered amine compounds and other light stabilizers. Furthermore, for the purpose of coloring, dyes or pigments may be added.

Examples of plasticizers include: vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate , Vinyl stearate, vinyl cyclohexane carboxylate, vinyl benzoate-like vinyl carboxylates or styrene.

Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, lactone-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. These antioxidants may be used individually by 1 type, and may use 2 or more types together.

In view of the compatibility or high effect of the adhesive, the metal corrosion inhibitor can be exemplified by benzotriazole-based resins.

Examples of the tackifier include rosin resins, terpene resins, terpene phenol resins, lavender-indene resins, styrene resins, xylene resins, phenol resins, and petroleum resins.

Examples of the silane coupling agent include mercapto alkoxy silane compounds (for example, alkoxy oligomers substituted with mercapto groups) and the like.

Examples of ultraviolet absorbers include benzotriazole-based compounds and benzophenone-based compounds. However, when ultraviolet rays are used as active energy rays during post-curing, it is preferable to add them within a range that does not hinder the polymerization reaction.

＜Manufacturing method of adhesive sheet＞ The manufacturing method of the adhesive sheet of the present invention preferably includes the following steps: coating the above-mentioned adhesive composition on the release sheet to form a coating film; and heating the cured product to make the coating film in a semi-cured state. By heating the coating film, the cross-linkable acrylic polymer A and the cross-linking agent B react to form a cured product (adhesive layer) in a semi-cured state. That is, during heating, the polymerization reaction of the monomer using the photopolymerization initiator E does not proceed in the coating film, or even if it progresses, it is very small. Therefore, the monomers C, D and the photopolymerization initiator contained in the adhesive composition At least a part of E will be contained in the adhesive layer in an unreacted state. The adhesive sheet of the present invention preferably has post-curing properties and active energy ray curability.

In addition, in order to make the adhesive composition in a semi-hardened state, after the solvent is removed after coating, it is advisable to perform an aging treatment in which the adhesive sheet is allowed to stand at a certain temperature for a certain period of time. The aging treatment can be performed by standing still at 23°C for 7 days, for example.

The application of the adhesive composition can be performed using a known coating device. Examples of the coating device include: knife coater, air knife coater, roll coater, bar coater, gravure coater, micro-gravure coater, bar knife coater, die lip Coating machine, die coating machine, curtain coating machine, etc.

For heating the coating film formed by applying the adhesive composition, a known heating device such as a heating furnace and an infrared lamp can be used.

<How to use the adhesive sheet> In the use method of the adhesive sheet of the present invention, it is preferable to make the adhesive layer of the adhesive sheet contact the surface of the adherend. In the use method of the adhesive sheet, it is more desirable that the adhesive layer of the adhesive sheet is attached to the adherend in the semi-hardened state, and the active energy rays are irradiated to harden the adhesive layer. That is, the adhesive sheet of the present invention is a two-stage curing type adhesive sheet, which has an adhesive layer that is semi-cured by heat only before bonding, and the adhesive layer is cured by active energy rays after bonding.

＜Use of adhesive sheet＞ The adhesive sheet of the present invention is preferably used for bonding optical members, which are optical members that require durability and must be molded after being laminated with the optical member.

After the adhesive sheet of the present invention is attached to an adherend such as a substrate and cured afterwards, even if it is exposed to a high-temperature and high-humidity environment, the substrate has excellent adhesion and durability, and therefore can suppress floating or The generation of flaking. The adhesive sheet of the present invention can be prevented from floating or peeling from the polycarbonate substrate even if it is exposed to a high-temperature and high-humidity environment after being bonded to a polycarbonate substrate and then cured.

The adhesive sheet of the present invention can also be bonded to optical members such as polarizing plates. Here, the so-called polarizing plate includes a polarizer and a polarizer protective film, and the adhesive sheet of the present invention is preferably attached to the polarizer protective film. Examples of polarizer protective films include cycloolefin resin films, cellulose acetate resin films such as cellulose triacetate and cellulose diacetate, polyethylene terephthalate, polyethylene naphthalate, and polyethylene terephthalate. Polyester resin films such as butylene phthalate, polycarbonate resin films, acrylic resin films, polypropylene resin films, etc.

[Layered body] The present invention also relates to a laminated body having the above-mentioned adhesive sheet and an adherend. The laminated body includes: an adhesive layer that is cured by irradiating the adhesive layer of the adhesive sheet with active energy rays and then cured; and an adherend on at least one side of the adhesive layer after curing. That is, the laminate of the present invention has an adhesive sheet and an adherend provided on at least one side of the adhesive sheet, and the adhesive layer of the adhesive sheet is cured by irradiating active energy rays. When the adhesive sheet is a double-sided adhesive sheet, it is advisable to irradiate active energy rays in the state where the semi-cured adhesive sheet is used to bond the two adherends to form a laminate by hardening the adhesive layer. . Here, the adherend is more preferably a substrate and an optical member, and particularly preferably a polycarbonate substrate, polarizing plate, transparent film, transparent resin or glass.

Fig. 2 is a schematic cross-sectional view showing an example of the laminate of the present invention. 2 is a cross-sectional view showing an example of the structure of the laminate 20 in which the adhesive sheet 21 of the present invention is bonded to the base material 22 and the optical member 24. As shown in FIG. 2, the adhesive sheet 21 of the present invention is suitable for bonding to the substrate 22, and is suitable for bonding the substrate 22 and other optical components 24. In addition, the adhesive sheet 21 of the present invention can also be used for bonding with polarizing plates.

The optical members contained in the laminate include, for example, various constituent members in optical products such as touch panels and image display devices; or shatterproof films attached to the surface cover of the outermost layer. The constituent members of the touch panel include, for example, an ITO film provided with an ITO film on a transparent resin film, an ITO glass provided with an ITO film on the surface of a glass plate, and a transparent resin film coated with a conductive polymer. Conductive film, hard coat film, fingerprint resistant film, etc. Examples of constituent members of the image display device include anti-reflection films, alignment films, polarizing films, retardation films, and brightness enhancement films used in liquid crystal display devices.

The materials used in these components include glass, polycarbonate, polyethylene terephthalate, polymethyl methacrylate, polyethylene naphthalate, cycloolefin polymer, and cellulose triacetate. , Polyimide, cellulose amide, etc.

When the adhesive sheet of the present invention is a double-sided adhesive sheet, it can be used for bonding of two adherends. At this time, the adhesive sheet of the present invention can be used for bonding of transparent optical films inside touch panels, bonding of transparent optical films and glass, bonding of transparent optical films of touch panels and liquid crystal panels , The bonding of cover glass and transparent optical film, the bonding of cover glass and transparent optical film, etc., are useful when any of the components is a polycarbonate substrate. As the film for transparent optics, general films used in the optical field such as polyethylene terephthalate film, acrylic film, polycarbonate film, cellulose triacetate film, or cycloolefin polymer film can be used. In addition, a hard coat layer may be provided on a transparent optical film or a polycarbonate substrate.

Fig. 3 is a schematic cross-sectional view showing another example of the laminate of the present invention. As shown in Fig. 3, the adherend may have a drop portion (27a, 27b, 27c, 27d). In Fig. 3, the base material has drop portions (27a, 27b), and the optical member has drop portions (27c, 27d). In addition, the thickness of the drop portion (27a, 27b, 27c, 27d) is usually 5 to 60 μm. According to this, the adhesive sheet 21 of the present invention can also be attached to a member having a drop portion, and can cater to the unevenness generated from the drop portion.

[Method of manufacturing laminated body] The manufacturing method of the laminated body includes the following steps: after bonding the adhesive layer of the adhesive sheet to the adherend in a semi-cured state, irradiating active energy rays to harden the adhesive layer. That is, the manufacturing method of the laminated body of the present invention sequentially includes: step 1, applying the adhered volume layer on at least one side of the adhesive sheet; and step 2, by irradiating the adhesive layer of the adhesive sheet with active energy rays , After curing the aforementioned adhesive layer. Before the active energy ray is irradiated, the adhesive layer of the adhesive sheet is in a semi-cured state, so the initial adhesion to the substrate is good. Accordingly, after the adhesive sheet is attached to the adherend, the adhesive layer is post-cured by the active energy rays, thereby increasing the cohesive force of the adhesive layer and the adhesion to the adherend. In addition, the post-cured adhesive layer can prevent deformation or strain of the substrate.

Examples of the active energy rays include ultraviolet rays, electron beams, visible rays, X-rays, ion beams, etc., which can be appropriately selected according to the photopolymerization initiator contained in the adhesive layer. Among them, from the viewpoint of versatility, ultraviolet light or electron beam is preferable, and ultraviolet light is particularly preferable.

As the light source of ultraviolet light, for example, high-pressure mercury lamp, low-pressure mercury lamp, ultra-high pressure mercury lamp, metal halide lamp, carbon arc, xenon arc, electrodeless ultraviolet lamp, etc. can be used.

For example, the electron beam can be used from various electron beam accelerators such as Kirklauf-Walton type, Van der Graff type, resonance transformer type, insulating core transformer type, linear type, high frequency and high voltage type, high frequency type, etc. Electron beam.

The irradiation output of ultraviolet light should be set to 100~10000mJ/cm ² , more preferably 500~5000mJ/cm ² . In addition, in the present invention, when the above-mentioned physical properties (1) to (3) are measured, active energy rays are irradiated so that the accumulated light amount constitutes 3000 mJ/cm ² . Example

Examples and comparative examples are listed below to more specifically illustrate the characteristics of the present invention. The materials, usage amount, ratio, processing content, processing sequence, etc. shown in the following examples can be appropriately changed as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the specific examples shown below.

<Synthesis of cross-linkable acrylic polymer A (A-1)> By solution polymerization in ethyl acetate, a crosslinkable acrylic polymer A (A-1) having an acid component was produced. Specifically, butyl acrylate monomer (BA), methyl acrylate monomer (MA), methyl methacrylate (MMA), and acrylic acid (AA) are made up of 90:1:4:6 by mass ratio. It is blended in this way, and AIBN (azobisisobutyronitrile) as a radical polymerization initiator is dissolved in the solution. The solution was heated to 60°C to perform random copolymerization, and a crosslinkable acrylic polymer A (A-1) was obtained.

The 21% by mass solution of the crosslinkable acrylic polymer A (A-1) had a solution viscosity of 4900 mPa at 23°C. s. In addition, the glass transition temperature (Tg) obtained from the composition of the crosslinkable acrylic polymer A (A-1) using the FOX formula was -21°C.

<Synthesis of cross-linkable acrylic polymer A (A-2)> By solution polymerization in ethyl acetate, a crosslinkable acrylic polymer A (A-2) without an acid component was produced. Specifically, the 2-methoxyethyl acrylate monomer (MEA), 2-hydroxyethyl acrylate monomer (2HEA), methyl methacrylate (MMA), diethyl acrylamide (DEAA) And butyl acrylate (BA) are blended in a mass ratio of 70:10:10:5:5, and AIBN (azobisisobutyronitrile) as a radical polymerization initiator is dissolved in the solution. The solution was heated to 60° C. to perform random copolymerization to obtain a crosslinkable acrylic polymer A (A-2).

The solution viscosity of a 35% by mass solution of the crosslinkable acrylic polymer A (A-2) at 23°C is 2000 mPa. s. In addition, the glass transition temperature (Tg) obtained from the composition of the crosslinkable acrylic polymer A (A-2) using the FOX formula was -11°C.

[Example 1] With respect to 100 parts by mass of the crosslinkable acrylic polymer A (A-1), 0.05 parts by mass of an epoxy compound (manufactured by Mitsubishi Gas Chemical Corporation, TETRAD X) as a crosslinking agent B is added as a multifunctional monomer C 5 parts by mass of ethylene oxide modified diacrylate (manufactured by Toagosei Co., Ltd., ARONIX M211B, Tg=75°C), isocamyl acrylate as a monofunctional monomer E (manufactured by Osaka Organic Chemical Industry Co., Ltd., IBXA, Tg =97°C) 5 parts by mass, as the photopolymerization initiator D, 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by Japan, IRGACURE184) (abbreviated as "Irg184") 0.7 parts by mass, with a solid content concentration of 40 parts by mass % By adding ethyl acetate as a solvent to prepare an adhesive composition.

The above-mentioned adhesive composition was coated on the first release sheet (heavy release film, manufactured by Teijin DuPont Films, a polyethylene terephthalate film subjected to mold release treatment). The coating was performed using a doctor blade (Doctor Blade) YD type manufactured by Yoshimitsu Seiki Co., and the thickness after drying was 25 μm. Then, using a hot air dryer, it was dried at 100° C. for 3 minutes to remove the solvent to form an adhesive sheet with a semi-cured adhesive layer.

A second release sheet (light release film, manufactured by Teijin DuPont Films), which has higher release properties than the first release sheet and has been subjected to a mold release process, is attached to one side of the adhesive sheet to form an attached sheet. The adhesive sheet of Example 1 of the adhesive sheet of the release sheet.

[Example 2] Except that the addition amounts of the multifunctional monomer C and the monofunctional monomer E were changed to 7 parts by mass in Example 1, they were set to be the same as in Example 1. The adhesive composition and the adhesive with the release sheet were prepared Sheet.

[Example 3] Except that the addition amounts of the multifunctional monomer C and the monofunctional monomer E were changed to 15 parts by mass in Example 1, they were set to be the same as in Example 1, and an adhesive composition and an adhesive with a release sheet were prepared. Sheet.

[Example 4] Except that the addition amount of the multifunctional monomer C was changed to 15 parts by mass in Example 1, and the monofunctional monomer E was not added at the same time, it was set to be the same as Example 1, and an adhesive composition and attached peeling were obtained. Adhesive sheet of sheet.

[Comparative Example 1] Except that the addition amount of crosslinking agent B was changed to 0.5 parts by mass in Example 1, the addition amount of multifunctional monomer C was changed to 20 parts by mass, and the addition amount of monofunctional monomer E was changed to 15 parts by mass. With the exceptions, it was the same as in Example 1, and an adhesive composition and an adhesive sheet with a release sheet were prepared.

[Comparative Example 2] With respect to 100 parts by mass of crosslinkable acrylic polymer A (A-2), 0.5 parts by mass of a diisocyanate compound (manufactured by Mitsui Chemicals Co., Ltd., TAKENATE D-110N) as crosslinking agent B was added as a multifunctional Ethylene oxide modified diacrylate of monomer C (manufactured by Toagosei Co., Ltd., ARONIX M211B, Tg=75°C) 15 parts by mass, isocamyl acrylate as a monofunctional monomer E (manufactured by Osaka Organic Chemical Industry Co., Ltd., IBXA, Tg=97°C) 15 parts by mass, ethyl acetate was added as a solvent so that the solid content concentration constitutes 40% by mass to prepare an adhesive composition, except that it was the same as in Example 1, and prepared Adhesive composition and adhesive sheet with release sheet.

[Measurement and Evaluation] ＜Acid value＞ In a 100ml Erlenmeyer flask, use a precision balance to accurately weigh the adhesive composition so that the solid content of the crosslinkable acrylic polymer A prepared in the above as the sample constitutes about 2g, and toluene/2-propanol/ Water=5/5/0.5 (weight ratio) mixed solvent 10ml and dissolved. Next, add 1 to 3 drops of p-naphtholbenzene solution as an indicator to the container, and stir thoroughly until the sample becomes uniform. Titrate it with 0.1N potassium hydroxide-2-propanol solution, and set the end point of neutralization when the light red of the indicator has continued for 30 seconds. From this result, the value obtained using the following formula (1) was taken as the acid value of the sample.

Acid value (mgKOH/g)=[cKOH×(V1-V0)×5.611]/S (1) In the formula (1), cKOH is the molar concentration (mol/L) of the 0.1N potassium hydroxide-2-propanol solution, and V1 is the 0.1mol/L potassium hydroxide-2-propanol solution required for the titration of the sample Volume (mL), V0 is the volume (mL) of 0.1 mol/L potassium hydroxide-2-propanol solution required for the titration of the blank test, and S is the sample collection volume (g).

＜Gel fraction＞ The adhesive layer was cut into 100mm×60mm, and a semi-hardened state test sample was produced.

The adhesive layer was cut into a size of 100 mm×60 mm, and the first release sheet side of the self-weight separator was irradiated with ultraviolet rays so that the accumulated light amount constitutes 3000 mJ/cm ^{2 to} prepare a post-cured measurement sample.

Approximately 0.1 g of the adhesive sheet of each measurement sample was collected in the sample bottle, 30 ml of ethyl acetate was added and shaken for 24 hours. Then, the contents of the sample bottle were filtered out with a stainless steel wire mesh of 150 mesh, and the residue on the wire mesh was dried at 100°C for 1 hour, and the dry mass (g) was measured. Using the following formula 1, the gel fraction was calculated from the obtained dry mass. Gel fraction (mass%)=(dry mass/collected mass of adhesive sheet)×100…Equation 1

＜Probe viscosity value＞ Peel off the second release sheet of the light release film of the adhesive sheet and stick it on the PET film to produce a semi-cured state test sample.

Peel off the second release sheet of the light release film of other adhesive sheets, and stick it on the PET film. Next, ultraviolet rays were irradiated on the side of the first release sheet of the self-weight separator to produce a post-cured measurement sample so that the accumulated light amount constitutes 3000 mJ/cm ² .

Each measurement sample was cut into 3 cm×3 cm, and the measurement was performed under the following conditions using a probe viscosity tester. The measurement temperature is 23°C and the relative humidity is 50%. Measuring machine: NS probe viscosity tester (manufactured by NICHIBAN) Probe diameter: 5mmφ Probe substrate: stainless steel surface finishing AA#400 grinding mirror Weight: 19.6g (made of brass) Probe moving speed: 1.0cm/sec Residence time: 1 second

<Elongation at break> The elongation at break was measured in accordance with JIS K 7161-1. At this time, the stretching speed was set to 10 mm/min, and the measurement was performed in an environment of 23° C. and a relative humidity of 50%. In addition, the measurement sample used the following: an adhesive layer having a thickness of 25 μm, a width of 60 mm, and a length of 200 mm was rounded in the longitudinal direction and processed into a cylindrical shape with a cross-sectional area of 5 mm ² and a height of 60 mm. The sample is placed and stretched so that the distance between the chucks is 30 mm, and the elongation when the sample is broken is set as the elongation at break. In addition, the measurement equipment used the AUTOGRAPH AGS-X manufactured by Shimadzu Corporation.

<Fixed load peeling distance> Peel off the light peeling spacer of the second peeling sheet, and use a hand roller to paste a cellulose triacetate film (manufactured by FUJIFILM, FUJITAC TD60UL, thickness 60μm) to replace the peeled off Separate parts to produce laminated film. This laminated film was cut into a size of 25 mm in width and 100 mm in length, and the first release sheet was peeled off. Secondly, using a 2kg crimping roller, the exposed area of 25mm wide and 100mm long adhesive surface with a width of 25mm and a length of 75mm is pasted on the adherend (polycarbonate plate with hard coating: manufactured by Mitsubishi Gas Chemical Corporation, IUPILON MR58 thickness 1mm) hard-coated side. In this state, so that at 40 ℃, holding the autoclave was 5 atmospheric conditions for 30 minutes and the adhesion to the PC board to accumulated light quantity constituting 3000mJ / cm Embodiment ² of from cellulose triacetate film side irradiated with ultraviolet rays, Make a test piece.

Then, the test piece was placed in an environment of i) 85°C, 85% relative humidity and ii) 85°C and relative humidity less than 10% for 24 hours, and then at i) 85°C, relative humidity 85% and ii) 85 In an environment with a temperature of less than 10% and a relative humidity of less than 10%, hang a weight 34 of 100g on the longitudinal end of the non-laminated area (width 25mm, length 25mm) of the laminated film as shown in Figure 4, A load of 100g is applied to the plane of 32 in a direction of 90°, and placed in this state for another 5 minutes. The length L (the peeling distance under a constant load) at the point where the laminated film has been peeled off is measured. The evaluation criteria are as follows, A and B are acceptable (allowable ranges), and C is unacceptable. A: Peeling cannot be confirmed, or peeling less than 1mm is observed B: Peeling of 1mm or more and 50mm or less is observed C: Peeling larger than 50mm is observed

＜Durability＞ The second release sheet of the light release film of the adhesive layer was peeled off and attached to a cellulose triacetate film (manufactured by FUJIFILM, FUJITAC TD60UL, thickness 60 μm).

Next, peel off the first release sheet of the heavy-duty isolation film and stick it on a PC board (polycarbonate board with hard coating: manufactured by Mitsubishi Gas Chemical Corporation, IUPILON MR58 thickness 1mm). The sample of cellulose triacetate film/adhesive layer/PC board structure is subjected to autoclave treatment (40°C, 0.5MPa, 30min), and secondly, the accumulated light quantity constitutes 3000mJ/cm ² from cellulose triacetate Ultraviolet rays were irradiated on the film side to prepare a test sample with a size of 100mm×200mm.

Then, the test specimens were allowed to stand for 240 hours in an environment of i) 85°C, a relative humidity of 85%, and ii) 85°C, and a relative humidity of less than 10%.

Then, observe the test sample, and observe whether there is floating and peeling. In addition, the judgment of i) condition shows the durability of high temperature and high humidity, and the judgment of condition ii) shows the durability of high temperature. The evaluation criteria are as follows, a is a pass (allowable range), and b is a failure. a: No floating or peeling above 1.0mm is observed b: floating and/or peeling above 1.0mm are observed

＜Wrinkles＞ The test environment of the aforementioned durability test ii) In the sample at 85°C and relative humidity less than 10%, visually observe whether there are wrinkles. The evaluation criteria are as follows, A and B are acceptable (allowable ranges), and C is unacceptable. A: No wrinkles are observed B: The generation of wrinkles smaller than 5mm is observed C: The generation of wrinkles over 5mm is observed

[Table 1]

It can be seen from Table 1 above that the adhesive sheets of the examples can also exhibit excellent substrate adhesion and durability under high temperature and high humidity conditions, in addition to high temperature conditions. In addition, the adhesive sheet of the embodiment does not stick to the end surface, and is not prone to wrinkles in applications such as bonding large-screen optical components (construction applications in a larger area), and the workability is also good. On the other hand, the adhesive sheet of the comparative example has poor substrate adhesion and durability under high-temperature conditions and high-temperature and high-humidity conditions, and/or poor workability in construction applications in a large area (wrinkles can be seen The production).

1,21: Adhesive sheet 11: Adhesive layer 12a: Transparent substrate or release sheet 12b: peel off sheet 20: Laminated body 22: Substrate 24: Optical components 27a, 27b, 27c, 27d: drop part 30: cellulose triacetate film 32: adherend 34: scale hammer L: length (fixed load peeling distance)

Fig. 1 is a schematic cross-sectional view showing the adhesive sheet of the present invention having a release sheet or substrate. Fig. 2 is a schematic cross-sectional view showing an example of the laminate of the present invention. Fig. 3 is a schematic cross-sectional view showing another example of the laminate of the present invention. Fig. 4 is a diagram illustrating a method of measuring a peeling distance under a constant load in the present invention.

1: Adhesive sheet

11: Adhesive layer

12a: Transparent substrate or release sheet

12b: peel off sheet

Claims (9)

An adhesive sheet having an adhesive layer in which an adhesive composition has been semi-hardened. The aforementioned adhesive composition contains a crosslinkable acrylic copolymer A with an acid component, a crosslinking agent B, and two in the molecule The above-mentioned reactive double bond multifunctional monomer C and photopolymerization initiator D, the glass transition temperature (Tg) of the aforementioned crosslinkable acrylic copolymer A is -40°C or higher, the aforementioned adhesive layer has post-curing properties, when When the adhesive layer is irradiated with active energy rays to form 3000mJ/cm ² of integrated light and then cured, the adhesive layer satisfies the following physical properties (1) and (2); Physical properties (1): Tensile speed 10mm/min The breaking elongation measured in the tensile test is more than 300%; Physical properties (2): measured under the following measuring conditions at i) 85℃, relative humidity 85% and ii) 85℃, relative humidity less than 10% The peeling distance of each fixed load is less than 50mm: (Measurement conditions) The area of 25mm in width and 75mm in length on the adhesive surface of the adhesive layer with a width of 25mm and a length of 100mm is attached to the adherend, and then cured; in i) Under 85°C, relative humidity 85% and ii) 85°C, relative humidity less than 10%, fix the adherend in the horizontal direction with the non-laminated area of the adhesive layer hanging downward; on the adhesive layer A load of 100g is applied to the longitudinal end of the non-bonding area for 5 minutes, and the distance between the bonding area of the adhesive layer and the adherend is measured, as i) 85℃, relative humidity 85% and ii) 85℃ , The relative humidity is less than 10% at each fixed load peeling distance. The adhesive sheet of claim 1, wherein the aforementioned adhesive composition contains a monofunctional monomer E having one reactive double bond in the molecule. The adhesive sheet of claim 2, wherein the content of the aforementioned monofunctional monomer E is 1-20 parts by mass relative to 100 parts by mass of the aforementioned crosslinkable acrylic copolymer A. The adhesive sheet according to any one of claims 1 to 3, wherein the content of the aforementioned multifunctional monomer C is 1-20 parts by mass relative to 100 parts by mass of the aforementioned crosslinkable acrylic copolymer A. The adhesive sheet according to any one of claims 1 to 4, wherein the acid value of the crosslinkable acrylic copolymer A is 1 mgKOH/g or more. The adhesive sheet according to any one of claims 1 to 5, wherein the difference between the gel fraction of the adhesive layer in the semi-cured state and the gel fraction after post-curing is 15% or more. An adhesive sheet with a peeling sheet provided with a pair of peeling sheets with different peeling forces on both sides of the adhesive sheet of any one of claims 1 to 6. A laminated body having an adhesive sheet according to any one of claims 1 to 6 and an adherend provided on at least one side of the adhesive sheet, wherein the adhesive layer of the adhesive sheet is irradiated with active energy rays hardening. A manufacturing method of laminated body, in order: Step 1. Place the adhered volume layer on at least one side of the adhesive sheet according to any one of claims 1 to 6; and Step 2, by irradiating the adhesive layer of the adhesive sheet with active energy rays, the adhesive layer is post-cured.

Images