TWI728035B - Double-sided adhesive plate, display body and manufacturing method of display body - Google Patents

Abstract

The subject of the present invention is to provide a double-sided adhesive sheet with excellent step-following properties and good workability, and a display body obtained by using the double-sided adhesive sheet, and a manufacturing method thereof.

The solution of the present invention is a double-sided adhesive sheet 2 comprising: a first adhesive layer 21 as an outer layer on one side; a second adhesive layer 22 as an outer layer on the other side; and In the intermediate layer 23 between the first adhesive layer 21 and the second adhesive layer 22, the glass transition temperature of the intermediate layer 23 is 0°C or more and 60°C or less.

Description

Double-sided adhesive board, display body and manufacturing method of display body

The present invention relates to a double-sided adhesive sheet suitable for pasting constituent members of a display body, a display body obtained by using the double-sided adhesive sheet, and a manufacturing method thereof.

In recent years, various mobile electronic devices such as smartphones and tablet computers have equipped displays that use display modules such as liquid crystal elements, light-emitting diodes (LED elements), and organic electroluminescence (organic EL) elements. There are also more cases where the display is used as a touch panel. In the above-mentioned display, usually, a protective plate is provided on the surface of the display module.

Here, between the protection board and the display module, there is provided a gap where the deformed protection board will not hit the display module even when the protection board is deformed by an external force.

However, if there is a void as described above, that is, an air layer, the light reflection loss due to the difference in refractive index between the protective plate and the air layer, and the difference in refractive index between the air layer and the display module is large, and there is a The problem of reducing the picture quality of the display.

Therefore, there is a proposal to improve the image quality of the display by filling the gap between the protective plate and the display module with an adhesive layer. However, on the display module side of the protective plate, there is a step in the frame-shaped printed layer. If the adhesive layer cannot follow the level difference, the adhesive layer will float near the level difference, so light reflection will occur. Shot loss. Therefore, in the above-mentioned adhesive layer, step followability is required.

In order to solve the above-mentioned problems, in Patent Document 1, as an adhesive layer that fills the gap between the protective plate and the display module, it is disclosed that the shear storage elastic modulus (G') at 25° C. and 1 Hz is 1.0×10 ^{Adhesive layer below 5} Pa and with a gel fraction of 40% or more.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2010-97070

The invention disclosed in Patent Document 1 reduces the storage elastic modulus (G') of the adhesive layer at room temperature to improve the followability of the step. However, if the storage elastic modulus (G') at room temperature is as low as described above, the drape strength of the adhesive layer will decrease, which will deteriorate the workability. For example, when cutting the adhesive sheet, the adhesive layer will collapse and the adhesive will overflow on the cut surface, causing problems such as adhesion of the adhesive to the blade.

The present invention was completed in view of the above-mentioned actual situation, and aims to provide a double-sided adhesive sheet with excellent step followability and good processability, and a display body obtained by using the double-sided adhesive sheet and a manufacturing method thereof. .

In order to achieve the above objectives, first, the present invention provides a double-sided adhesive sheet, which is characterized by having: a first adhesive layer as an outer layer on one side; and a second adhesive layer as an outer layer on the other side Agent layer; and located above In the intermediate layer between the first adhesive layer and the second adhesive layer, the glass transition temperature of the intermediate layer is 0°C or more and 60°C or less (Invention 1).

According to the above invention (Invention 1), by setting the glass transition temperature of the intermediate layer in the above range, the intermediate layer has a certain degree of hardness at room temperature, thereby increasing the film strength of the entire double-sided adhesive sheet, and making Good processability. In addition, by setting the glass transition temperature of the intermediate layer within the above-mentioned range, the intermediate layer can be softened by heating, thereby making the entire double-sided adhesive sheet excellent in flexibility and step followability.

In the above invention (Invention 1), the first adhesive layer and the second adhesive layer preferably have active energy ray curability (Invention 2).

In the above inventions (Inventions 1 and 2), the intermediate layer preferably has active energy ray curability (Invention 3).

In the above invention (Invention 3), the intermediate layer preferably contains a resin having a glass transition temperature of 0°C or more and 60°C or less, and an active energy ray curable component (Invention 4).

Regarding the double-sided adhesive sheets of the above inventions (Inventions 1 to 4), the Young's modulus is preferably 0.01 MPa or more and 100 MPa or less (Invention 5).

In the above inventions (Inventions 1 to 5), the ratio of the thickness of the intermediate layer to the total thickness of the first adhesive layer and the second adhesive layer is preferably 0.05 or more and 2 or less (Invention 6).

Regarding the double-sided adhesive sheet of the aforementioned inventions (Inventions 1 to 6), it is preferable to adhere one display component and another display component (Invention 7) having a step difference at least on the surface to be adhered.

Second, the present invention provides a double-sided adhesive sheet with a peel-off sheet attached A sheet characterized by comprising: two peeling plates; and the double-sided adhesive sheet sandwiched by the peeling plate so as to contact the peeling surfaces of the two peeling plates (Inventions 1 to 7) (Inventions 1 to 7) 8).

Third, the present invention provides a display body characterized by: a display body constituent member having a step at least on the surface to be pasted; other display body constituent members; and a combination of the above-mentioned one display body constituent member and the above-mentioned other display body It is obtained by the above-mentioned double-sided adhesive sheet (Invention 1-7) in which the constituent members are bonded to each other (Invention 9).

Fourth, the present invention provides a display body characterized by: having a display body constituent member having a step at least on the surface to be adhered; other display body constituent members; and the above-mentioned one display body constituent member and the above-mentioned other display body are formed The hardened double-sided adhesive sheet (Invention 10) is a cured double-sided adhesive sheet formed by curing the above-mentioned double-sided adhesive sheets (Inventions 2, 3) in which the members are bonded to each other.

Fifthly, the present invention provides a method for manufacturing a display body, characterized in that: a laminated body formed by bonding a display body constituent member and another display body constituent member through the above-mentioned double-sided adhesive sheet (Inventions 2, 3) ; The double-sided adhesive sheet of the laminate is irradiated with active energy rays to harden the double-sided adhesive sheet (Invention 11).

Regarding the double-sided adhesive sheet of the present invention, it has excellent step followability and good processability. In addition, regarding the display of the present invention, the double-sided adhesive sheet having excellent step-following properties can suppress the occurrence of voids, floating, etc. in the vicinity of the step. Furthermore, according to the method for manufacturing a display body of the present invention, it is possible to obtain a display body that suppresses the occurrence of voids, floating, etc. near the step.

1‧‧‧Double-sided adhesive sheet with peel-off sheet

2‧‧‧Double-sided adhesive plate

2'‧‧‧Double-sided adhesive plate after hardening

21‧‧‧The first adhesive layer

22‧‧‧Second adhesive layer

23‧‧‧Middle floor

31、32‧‧‧Peeling plate

4‧‧‧Display body

51‧‧‧The first display body component

52‧‧‧The second display body component

6‧‧‧Printing layer

Fig. 1 is a cross-sectional view of an adhesive sheet according to an embodiment of the present invention.

[Fig. 2] is a cross-sectional view of a laminated body related to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described.

[Double-sided adhesive plate]

Fig. 1 shows a cross-sectional view of a double-sided pressure-sensitive adhesive sheet according to an embodiment of the present invention.

As shown in FIG. 1, the double-sided adhesive sheet 2 of this embodiment includes: a first adhesive layer 21 as an outer layer on one side; a second adhesive layer 22 as an outer layer on the other side And the intermediate layer 23 located between the first adhesive layer 21 and the second adhesive layer 22.

Regarding the double-sided adhesive sheet 2 of this embodiment, it is sandwiched by the above-mentioned peeling sheet pieces 31, 32 so as to contact the peeling surfaces of the two peeling sheet pieces 31, 32, and this laminate is referred to as a peeling plate attached. The double-sided adhesive board of the film. However, it is not necessary to laminate the peeling plate 31 and/or the peeling plate 32 on the double-sided adhesive sheet 2. In addition, the peeling surface of the peeling sheet in this specification refers to the peeling surface of the peeling sheet, including any one of the surface subjected to peeling treatment and the surface that shows peeling even if no peeling treatment is applied. By.

In this embodiment, the first adhesive layer 21 and the second adhesive layer 22 are the outermost layers of the double-sided adhesive sheet 2, respectively, the first adhesive layer 21 is in contact with the peeling surface of the peeling sheet 31, and the second adhesive layer is The agent layer 22 is in contact with the peeling surface of the peeling sheet 32, but it is not limited to this. In addition, in this embodiment, the intermediate layer 23 and the first adhesive layer 21 are directly laminated, and the intermediate layer 23 and the second adhesive layer 22 Direct layering, but it is not limited to this.

The glass transition temperature (Tg) of the intermediate layer 23 in this embodiment is 0°C or more and 60°C or less. By setting the glass transition temperature of the intermediate layer 23 in this range, the intermediate layer 23 has a certain degree of hardness at room temperature. Thereby, the film strength of the entire double-sided adhesive sheet 2 is improved, and the workability is improved. For example, when the double-sided adhesive sheet 1 with a release sheet is processed and cut, the double-sided adhesive sheet 2 itself becomes less likely to collapse. In addition, due to the presence of the intermediate layer 23, it is relatively easy to collapse. The cross-sectional areas of the first adhesive layer 21 and the second adhesive layer 22 are also reduced, so that problems such as the adhesive overflowing on the cut surface and the adhesive adhering to the blade can be suppressed.

On the other hand, by setting the glass transition temperature of the intermediate layer 23 in the above-mentioned range, the intermediate layer 23 can be softened by heating, and the double-sided adhesive sheet 2 as a whole can be excellent in flexibility. Therefore, when the double-sided adhesive sheet 2 is adhered to an object having a step (for example, a display body constituent member), the double-sided adhesive sheet 2 is heated to make the double-sided adhesive sheet 2 become a step follower Those with excellent performance (initial step followability), while suppressing the occurrence of voids, floating, etc. near the step.

From the above viewpoint, the glass transition temperature of the intermediate layer 23 is preferably 20°C or higher, particularly preferably 30°C or higher. In addition, the glass transition temperature is preferably 60°C or less, especially 40°C or less. In addition, the measuring method of the glass transition temperature in this specification is as shown in the test example mentioned later.

Here, as described later, when the first adhesive layer 21 and the second adhesive layer 22 are curable with active energy rays, it is preferable that when the intermediate layer 23 is further curable with active energy rays, the The equal layer is irradiated with active energy rays to harden it, and the double-sided adhesive plate 2 is not only the initial step followability, even in the high Accompanied by high temperature and humidity, the followability of the step difference is also excellent. For example, even if a laminated body with a stepped object (for example, a display body constituent member) and a double-sided adhesive sheet 2 is placed under the conditions of 85°C and 85%RH for 72 hours, it is also It can suppress the occurrence of bubbles, floating, peeling, etc. near the level difference. Furthermore, here, the so-called hardening (the state in which it is hardened) refers to a state in which a new high-order structure is formed by the irradiation of active energy rays, and even if the active energy rays are further irradiated, there is little further high-order structure formation. . Whether a higher-order structure is further formed can be judged by, for example, the amount of change in the gel fraction. Specifically, by further irradiating active energy rays, when the increase in the gel fraction is small (preferably 5% or less), it can be said to be a hardened state.

1. The first adhesive layer and the second adhesive layer

The first adhesive layer 21 and the second adhesive layer 22 are not particularly limited as long as they can exert the above-mentioned effects due to the intermediate layer 23, and may be active energy ray curable or active energy ray non-curable. However, it is preferable that at least one of them is active energy ray curability, and it is more preferable that both the first adhesive layer 21 and the second adhesive layer 22 have active energy ray curability. Thereby, the double-sided adhesive sheet 2 can be made not only the initial step followability, but also the step followability under high temperature and high temperature conditions. Furthermore, the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer may be the same adhesive or different adhesives.

When at least one of the first adhesive layer 21 and the second adhesive layer 22 is non-curable with active energy rays, the adhesive constituting the adhesive layer may be, for example, an acrylic adhesive, a rubber-based adhesive, or a silicone adhesive. Any of ketone-based adhesives, urethane-based adhesives, polyester-based adhesives, polyvinyl ether-based adhesives, etc. What kind. In addition, the above-mentioned adhesive may be any one of latex type, solvent type or solvent-free type, and may also be any one of bridging type or non-bridging type. Among the above, acrylic adhesives are preferred.

Furthermore, the non-curing active energy ray adhesive layer may also be composed of an adhesive after active energy ray hardening (active energy ray hardening adhesive before hardening).

When at least one of the first adhesive layer 21 and the second adhesive layer 22 is active energy ray curable, the adhesive constituting the adhesive layer is an active energy ray curable adhesive (active energy ray curable adhesive) . The active energy ray curable adhesive preferably contains at least any one of active energy ray curable monomers, oligomers, and polymers, or a mixture of these. In addition to these, it may also contain active energy ray non-curing Any one of sexual monomers, oligomers and polymers, or a mixture of these.

The active energy ray curable adhesive is preferably composed of an adhesive composition containing: (meth)acrylate polymer (A); and an active energy ray curable compound (B) (hereinafter sometimes referred to as "adhesive Sexual composition P".) Obtained. The adhesive composition P preferably further contains a bridging agent (C). At this time, the obtained adhesive is composed of an adhesive obtained by bridging the (meth)acrylate polymer (A) of the adhesive composition P with a bridging agent (C) (preferably active energy ray The curable compound (B) does not polymerize but exists in the adhesive layer). In addition, in this specification, (meth)acrylate means both acrylate and methacrylate. Other similar terms are also the same. In addition, "polymer" also includes the concept of "copolymer".

(1) Active energy ray hardening adhesive

(1-1) (Meth) acrylate polymer (A)

(Meth)acrylate polymer (A), by containing alkyl (meth)acrylate alkyl having 1 to 20 carbon atoms as the monomer unit constituting the polymer, it can exhibit better adhesiveness . Examples of alkyl (meth)acrylates having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, ( N-Butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, (meth) N-decyl acrylate, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, palmyl (meth)acrylate, stearyl (meth)acrylate, etc. Among them, from the viewpoint of improving the adhesiveness, (meth)acrylate having 1 to 8 carbon atoms in the alkyl group is preferred, and n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate is particularly preferred. . In addition, these can be used individually or in combination of 2 or more types.

The (meth)acrylate polymer (A) preferably has an alkyl (meth)acrylate containing 40% by mass or more of alkyl groups and a carbon number of 1 to 20 as the monomer unit constituting the polymer, especially The content is preferably 50% by mass or more, and more preferably 60% by mass or more. When the alkyl (meth)acrylate is contained at least 40 masses, appropriate adhesiveness can be imparted to the (meth)acrylate polymer (A). In addition, the alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group preferably contains 90% by mass or less, particularly 80% by mass or less, and more preferably 70% by mass or less. By making the content of the alkyl (meth)acrylate 90% by mass or less, a desired amount of other monomer components can be introduced into the (meth)acrylate polymer (A).

The (meth)acrylate polymer (A) is preferably contained in the molecule A monomer containing a reactive functional group (a monomer containing a reactive functional group) serves as a monomer unit constituting the polymer. The reactive functional group derived from this reactive functional group-containing monomer reacts with a cross-linking agent (C) described later to form a cross-linking structure (three-dimensional network structure), and an adhesive having a desired cohesive force can be obtained.

Examples of monomers containing reactive functional groups contained in the (meth)acrylate polymer (A) constituting the monomer units of the polymer include monomers having a hydroxyl group in the molecule (hydroxyl-containing monomers). Monomer), a monomer having a carboxyl group in the molecule (a monomer containing a carboxyl group), a monomer having an amine group in the molecule (a monomer containing an amine group), and the like. Among these, a hydroxyl group-containing monomer having excellent reactivity with the cross-linking agent (C) and less adverse effects on the adherend is particularly preferred.

Examples of monomers containing a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth)acrylic acid. Hydroxyalkyl (meth)acrylates such as 2-hydroxybutyl, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like. Among them, in terms of the reactivity between the hydroxyl group of the obtained (meth)acrylate polymer (A) and the cross-linking agent (C) and the copolymerizability with other monomers, (meth)acrylic acid 2 -Hydroxyethyl or 4-hydroxybutyl (meth)acrylate is preferred. These can be used individually or in combination of 2 or more types.

Examples of monomers containing a carboxyl group include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Among them, from the viewpoint of the reactivity of the carboxyl group of the obtained (meth)acrylate polymer (A) with the bridging agent (C) and the copolymerization with other monomers, acrylic acid is preferred. These can be used individually or in combination of 2 or more types.

As the monomer containing an amine group, for example, aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, and the like can be cited. These can be used individually or in combination of 2 or more types. In addition, the nitrogen atom-containing monosystem described later is excluded from the amine group-containing monomer.

When the (meth)acrylate polymer (A) contains a hydroxyl-containing monomer as the monomer unit constituting the polymer, the lower limit of its content is preferably 3% by mass or more, especially 10% by mass or more Preferably, it is more preferably 15% by mass or more. In addition, the upper limit of its content is preferably 35% by mass or less, particularly preferably 30% by mass or less, and further preferably 25% by mass or less. When the (meth)acrylate polymer (A) contains a hydroxyl group-containing monomer as a monomer unit in the above-mentioned amount, a predetermined amount of hydroxyl groups will remain in the obtained adhesive. Hydroxy-based hydrophilic group. When such a hydrophilic group is present in the adhesive in a predetermined amount, even if the adhesive is placed under high temperature and high humidity conditions, it has good compatibility with the water immersed in the adhesive under the high temperature and high humidity conditions. As a result, it is possible to suppress the whitening of the adhesive at the time of returning to normal temperature and humidity (excellent heat and humid whitening resistance).

When the (meth)acrylate polymer (A) contains a carboxyl group-containing monomer as the monomer unit constituting the polymer, the lower limit of its content is preferably 0.5% by mass or more, and more preferably 3% by mass or more Good, especially with a quality of 7 or more. In addition, the upper limit of its content is preferably 20 mass or less, more preferably 17 mass or less, and particularly preferably 13 mass% or less.

Furthermore, when the coated system is easily affected by acid, for example, transparent conductive film or metal wiring, the (meth)acrylate polymer (A) preferably does not contain a carboxyl group-containing monomer as the constituent The monomer unit of the polymer. Thereby, it is possible to suppress, for example, corrosion of the transparent conductive film or metal wiring, Or change the resistance value of the transparent conductive film.

Here, the term "does not contain carboxyl group-containing monomers" means that it does not substantially contain carboxyl group-containing monomers. In addition to not containing carboxyl group-containing monomers at all, it is also allowed to contain the transparent conductive film or Monomers containing carboxyl groups to the extent of corrosion of carboxyl groups such as metal wiring. Specifically, in the (meth)acrylate polymer (A), the allowable amount of the carboxyl group-containing monomer contained as a monomer unit is 0.1% by mass or less, preferably 0.01% by mass or less.

The (meth)acrylate polymer (A) preferably contains a monomer having an alicyclic structure in the molecule (monomer containing an alicyclic structure) as a monomer unit constituting the copolymer. The alicyclic structure-containing monomer has a large volume, and by making it exist in the polymer, it is presumed that the gap between the polymers can be enlarged, and the resulting adhesive can be made excellent in flexibility. Therefore, by making the (meth)acrylate polymer (A) contain an alicyclic structure-containing monomer as a constituent monomer unit, an adhesive obtained by bridging the adhesive composition P can have excellent initial step followability.

The carbocyclic ring of the alicyclic structure of the monomer containing an alicyclic structure may have a saturated structure or may have an unsaturated bond in a part. In addition, the alicyclic structure may be a monocyclic alicyclic structure, or a polycyclic alicyclic structure such as a bicyclic ring and a tricyclic ring. From the viewpoint of expanding the distance between the obtained (meth)acrylate polymer (A) and effectively exerting the flexibility of the adhesive, the above-mentioned alicyclic structure is a polycyclic alicyclic structure (polycyclic structure) Better. Furthermore, considering the compatibility of the (meth)acrylate polymer (A) with other components, the above-mentioned polycyclic structure is particularly preferably bicyclic to tetracyclic. In addition, in the same way as above, from the viewpoint of effectively exerting the effect of the flexibility of the adhesive, the carbon number of the alicyclic structure (refers to the number of all carbons in the part forming the ring, and when the plural rings exist independently, it means The total carbon number), usually 5 The above is preferable, and 7 or more is particularly preferable. On the other hand, the upper limit of the carbon number of the alicyclic structure is not particularly limited, and as described above, from the viewpoint of compatibility, 15 or less is preferable, and 10 or less is particularly preferable.

As the alicyclic structure, for example, cyclohexyl skeleton, dicyclopentadiene skeleton, adamantane skeleton, isobornyl skeleton, cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononane skeleton, ring Decane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.), cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, cubane skeleton, basket Alkyl skeleton, room alkane skeleton, spiro ring skeleton, etc., including the dicyclopentadiene skeleton (the carbon number of the alicyclic structure: 10) and the adamantane skeleton (the carbon number of the alicyclic structure) which can exert more excellent durability : 10) Or an isobornyl skeleton (the carbon number of the alicyclic structure: 7) is preferable, especially if it contains an isobornyl skeleton.

The above-mentioned alicyclic structure-containing monomer is preferably a (meth)acrylate monomer containing the above-mentioned skeleton. Specifically, cyclohexyl (meth)acrylate and dicyclopentyl (meth)acrylate , Adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenoxyethyl (meth)acrylate, etc., among which it can perform better The durability of dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate or isobornyl (meth)acrylate is preferred, and isobornyl (meth)acrylate is particularly preferred. These can be used individually by 1 type, and can also be used in combination of 2 or more types.

When the (meth)acrylate polymer (A) contains an alicyclic structure-containing monomer as the monomer unit constituting the polymer, the (meth)acrylate polymer (A) contains 5% by mass or more Monomers with an alicyclic structure are preferable, especially 8 mass% or more are preferable, and 10 mass or more are more preferable. In addition, The (meth)acrylate polymer (A) preferably contains 40% by mass or less of monomers containing an alicyclic structure as the monomer unit constituting the polymer, and particularly preferably contains 30% by mass or less, and further It is better to contain 20% by mass or less. By setting the content of the alicyclic structure-containing monomer within the above-mentioned range, the initial step followability of the obtained adhesive can be more excellent.

The (meth)acrylate polymer (A) preferably contains a monomer having a nitrogen atom (a nitrogen atom-containing monomer) in the molecule as a monomer unit constituting the polymer. The presence of a monomer containing a nitrogen atom as a constituent unit in the polymer can promote the reaction between the (meth)acrylate polymer (A) and the bridging agent (C), impart polarity to the adhesive, and improve the cohesive force of the adhesive itself .

Examples of the above-mentioned monomers containing nitrogen atoms include: monomers having tertiary amine groups, monomers having amine groups, monomers having nitrogen-containing heterocycles, etc. Among them, monomers having nitrogen-containing heterocycles are preferred. .

As the monomer having a nitrogen-containing heterocyclic ring, for example, N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone , N-(meth)acrylic piperidine, N-(meth)acrylic pyrrolidine, N-(meth)acrylic aziridine, aziridinyl ethyl (meth)acrylate , 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide, etc., among which, N-(meth)acrylomorpholine, which exerts better adhesion, is preferred, and N-acrylomorpholine is particularly preferred.

Furthermore, as monomers containing nitrogen atoms other than the above-mentioned monomers having nitrogen-containing heterocycles, it is also possible to use, for example, (meth)acrylamide, N-methyl(meth)acrylamide, N- Hydroxymethyl (meth)acrylamide, N-tert-butyl (meth)propane Enamide, N,N-dimethyl(meth)acrylamide, N,N-ethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide , N-isopropyl(meth)acrylamide, N-phenyl(meth)acrylamide, dimethylaminopropyl(meth)acrylamide, N-vinylcaprolactam, ( Dimethylaminoethyl meth)acrylate and the like. The above nitrogen atom-containing monomers may be used singly or in combination of two or more kinds.

When the (meth)acrylate polymer (A) contains a nitrogen atom-containing monomer as the monomer unit constituting the polymer, the (meth)acrylate polymer (A) contains 1% by mass or more of nitrogen A monomer having an atom is preferred, particularly 2% by mass or more is preferred, and 5% by mass or more is further preferred. In addition, the (meth)acrylate polymer (A) preferably contains 40% by mass or less of a nitrogen atom-containing monomer as the monomer unit constituting the polymer, and particularly preferably contains 25% by mass or less, and further It is preferable to contain 15% by mass or less. The content of the monomer containing nitrogen atoms within the above range can effectively enhance the cohesive force of the resulting adhesive.

The (meth)acrylate polymer (A) may contain other monomers as monomer units constituting the polymer as desired. Other monomers are preferably monomers that do not contain reactive functional groups. As the other monomers, for example, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and other alkoxyalkyl (meth)acrylates, vinyl acetate , Styrene, etc. These can be used individually or in combination of 2 or more types.

The polymerization state of the (meth)acrylate polymer (A) may be a random copolymer or a block copolymer.

The lower limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 100,000 or more, especially 200,000 or more, and further preferably 30 Ten thousand or more is better. The lower limit of the weight average molecular weight of the (meth)acrylate polymer (A) is above the above, the film strength of the obtained adhesive can be made relatively higher, and the step following under high temperature and high humidity conditions can be improved. Sex. In addition, the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 900,000 or less, particularly preferably 800,000 or less, and further preferably 700,000 or less. When the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is not more than the above, the initial step followability of the obtained adhesive can be made more excellent. In addition, the weight average molecular weight in this specification is a standard polystyrene conversion value measured by a gel permeation chromatography (GPC) method.

In addition, in the adhesive composition P and the (meth)acrylate polymer (A), one type may be used alone, or two or more types may be used in combination.

(1-2) Active energy ray hardening compound (B)

When the adhesive composition P contains the active energy ray curable compound (B), the resulting adhesive layer becomes active energy ray curable. Furthermore, the active energy ray curability of the adhesive layer is adhesiveness before the active energy ray is irradiated, and the adhesive strength is improved by curing the active energy ray after being adhered to the body.

Here, when the adhesive composition P contains the cross-linking agent (C) described later in addition to the active energy ray-curable compound (B), it is presumed that the obtained adhesive layer is made of the above-mentioned (meth)acrylic acid The ester polymer (A) and the bridging agent (C) form a bridge structure, and the active energy ray-curable compound (B) remains unreacted (not polymerized) and is present in the adhesive layer. Then, when the adhesive layer is irradiated with active energy rays, the active energy ray curable compound (B) is mutually polymerized, and the polymerized active energy ray curable compound (B) is entangled with the (meth)acrylate poly The bridging structure (three-dimensional network structure) of compound (A) hardens the adhesive layer. The adhesive with this high-level structure has a high cohesive force and shows a relatively high elastic modulus. Therefore, the hardened first adhesive layer 21 and/or the second adhesive layer 22 are used as the outermost double-sided adhesive sheet 2 (corresponding to the double-sided adhesive sheet 2'after curing described later) has excellent step followability under high temperature and high humidity conditions.

The active energy ray curable compound (B) is not particularly limited as long as it is a compound that can be cured by irradiation with active energy rays to obtain the above-mentioned effects, and may be any of monomers, oligomers, or polymers, or It is a mixture of these. Among them, a polyfunctional acrylate-based monomer having a molecular weight of less than 1,000, which is excellent in compatibility with the (meth)acrylate polymer (A), etc., can be suitably cited.

Examples of polyfunctional acrylate monomers having a molecular weight of less than 1000 include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl Glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxytrimethyl acetate neopentyl glycol bis(meth) Base) acrylate, dicyclopentyl di(meth)acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified phosphate di(meth)acrylate, di(meth)acrylate Acrylic oxyethyl) isocyanurate, allylated cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2-acrylic acid) Oxyethoxy) phenyl] 茀, etc. 2-functional type; trimethylolpropane tri(meth)acrylate, dineopentylerythritol tri(meth)acrylate, propionic acid-modified dineopentylerythritol 3 (Meth)acrylate, neopentylerythritol tri(meth)acrylate, propylene oxide denatured trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl) isocyanurate, ε-caprolactone modified tris(2-(meth)acryloyloxyethyl) isocyanurate, etc. trifunctional type; diglycerol tetra(meth)acrylate, neopentyl tetracycline 4-functional type such as alcohol tetra(meth)acrylate; 5-functional type such as propionic acid denatured dineopentaerythritol penta(meth)acrylate; dineopentaerythritol hexa(meth)acrylate, caprolone Ester-modified hexafunctional type such as dineopentaerythritol hexa(meth)acrylate. Among the above, from the viewpoint of the step followability of the obtained adhesive, neopentylerythritol tri(meth)acrylate and ε-caprolactone were used to denature tris(2-(meth)acrylic acid ethylene oxide). Base) isocyanurate is preferred. These can be used individually by 1 type, and can also be used in combination of 2 or more types.

As the active energy ray-curable compound (B), an active energy ray-curable acrylic oligomer can also be used. The acrylic oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such acrylic oligomers include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, and silicone Acrylic series, etc.

The upper limit of the weight average molecular weight of the acrylic oligomer is preferably 50,000 or less, and particularly preferably 40,000 or less. In addition, the lower limit of the weight average molecular weight is preferably 1,000 or more, and particularly preferably 3,000 or more. These acrylic oligomers may be used singly or in combination of two or more kinds.

In addition, as the active energy ray-curable compound (B), an addition acrylate-based polymer in which a group having a (meth)acryloyl group is introduced into a side chain can also be used. Such an addition acrylate polymer can have a (meth)acrylic acid group and bridging properties by using a copolymer of (meth)acrylate and a monomer having a bridging functional group in the molecule. The functional group-reactive group compound is obtained by reacting a part of the bridging functional group of the copolymer.

The lower limit of the weight average molecular weight of the addition acrylate polymer is preferably 50,000 or more, and particularly preferably 100,000 or more. In addition, the upper limit of the weight average molecular weight is preferably 900,000 or less, and particularly preferably 500,000 or less.

The active energy ray-curable compound (B) can be selected from one of the above-mentioned multifunctional acrylate monomers, acrylate oligomers and addition acrylate polymers, or a combination of two or more can be used. It can be used in combination with active energy ray curable components other than these.

In the adhesive composition P, the content of the active energy ray curable compound (B) is important for (methyl ) 100 parts by mass of the acrylate polymer (A), and the lower limit is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and particularly preferably 5 parts by mass or more. On the other hand, from the viewpoint of preventing the active energy ray curable compound (B) from separating from the (meth)acrylate polymer (A), the upper limit of the above content is preferably 50 parts by mass or less, and 20 Parts by mass or less is more preferable, and further considering the viewpoint that the step followability under high-temperature and high-humidity conditions is better, 12 parts by mass or less is particularly preferable.

(1-3) Bridging agent (C)

The adhesive composition P preferably contains a bridging agent (C). By making the adhesive composition P contain the bridging agent (C), the (meth)acrylate polymer (A) can be bridged to form a three-dimensional network structure, and the cohesive force of the resulting adhesive can be improved, which can be further improved at high temperatures. Followability of step difference under high humidity conditions.

As the bridging agent (C), any one capable of reacting with the reactive group possessed by the (meth)acrylate polymer (A) may be used, and examples include isocyanate-based bridging agents, epoxy-based bridging agents, and amines. Bridging agent, melamine bridging Agent, aziridine-based bridging agent, hydrazine-based bridging agent, aldehyde-based bridging agent, oxazoline-based bridging agent, metal alkoxide-based bridging agent, metal chelate-based bridging agent, metal salt-based bridging agent, ammonium Salt-based bridging agent, etc. When the (meth)acrylate polymer (A) contains a hydroxyl-containing monomer as a monomer unit constituting the polymer, it is preferable to use an isocyanate-based bridging agent having excellent reactivity with the hydroxyl group. In addition, when the (meth)acrylate polymer (A) contains a carboxyl group-containing monomer as a monomer unit constituting the polymer, it is preferable to use an epoxy-based bridging agent having excellent reactivity with the carboxyl group. In addition, the bridging agent (C) can be used singly or in combination of two or more kinds.

The isocyanate-based bridging agent is one containing at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate; aliphatic polyisocyanates such as hexamethylene isocyanate; isophorone diisocyanate , Alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, etc., and such biuret, isocyanurate, and further with ethylene glycol, propylene glycol, neopentyl glycol, trimethylol Addition products of reactants of low-molecular-weight active hydrogen-containing compounds such as propyl propane and castor oil. Among them, from the viewpoint of reactivity with a hydroxyl group, aromatic polyisocyanate modified with trimethylolpropane is preferred, and toluene diisocyanate modified with trimethylolpropane is particularly preferred.

As the epoxy-based bridging agent, for example, 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane, N,N,N,N'-tetraglycidyl metadi Toluene diamine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidyl amine, etc. Among them, from the viewpoint of reactivity with a carboxyl group, 1,3-bis(N,N'- Diglycidylaminomethyl)cyclohexane is preferred.

For the content of the cross-linking agent (C) in the adhesive composition P, based on 100 parts by mass of the (meth)acrylate polymer (A), the lower limit is preferably 0.001 parts by mass or more, especially 0.01 parts by mass or more Preferably, it is more preferably 0.02 parts by mass or more. In addition, the upper limit is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and further preferably 1 part by mass or less.

By setting the content of the cross-linking agent (C) in the above range, the resulting adhesive has good cohesive force and can improve the step followability of the resulting adhesive under high-temperature and high-humidity conditions.

(1-4) Photopolymerization initiator (D)

When curing the active energy ray-curable adhesive, when ultraviolet rays are used as the active energy ray to be irradiated, the adhesive composition P preferably further contains a photopolymerization initiator (D). By including the photopolymerization initiator (D) in this way, the active energy ray-curable compound (B) can be efficiently polymerized, and the curing time for polymerization and the amount of active energy ray irradiation can be reduced.

As such a photopolymerization initiator (D), for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminobenzene Ethanone, 2,2-Dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl Propan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propan-1-one, 4-( 2-Hydroxyethoxy) phenyl-2-(hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, two Chlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone Ketone, 2-Chlorothioxanthone, 2,4- Dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylamino benzoate, oligo[2-hydroxyl -2-Methyl-1[4-(1-methylvinyl)phenyl]acetone], 2,4,6-trimethylbenzyldiphenylphosphine oxide, etc. These can be used individually or in combination of 2 or more types.

For the content of the photopolymerization initiator (D) in the adhesive composition P, based on 100 parts by mass of the active energy ray curable compound (B), the lower limit is preferably 0.1 parts by mass or more, especially 1 part by mass The above is better. In addition, the upper limit is preferably 30 parts by mass or less, and particularly preferably 10 parts by mass or less.

(1-5) Various additives

In the adhesive composition P, various additives commonly used in acrylic adhesives can be added as desired, for example, silane coupling agent, anti-static agent, adhesion imparting agent, oxidation inhibitor, light stabilizer, softener, filler , Refractive index modifier, etc.

In addition, the adhesive composition P refers to a mixture of various components remaining in the adhesive in the original state or in the state after the reaction, and the components removed in the drying step, for example, the polymerization solvent or dilution described later The solvent is not included in the adhesive composition P.

(1-6) Manufacturing of adhesive composition

The adhesive composition P can be produced by producing the (meth)acrylate polymer (A), and the obtained (meth)acrylate polymer (A) and the active energy ray curable compound (B) can be mixed at the same time , As desired, it is manufactured by adding a cross-linking agent (C), a photopolymerization initiator (D), and additives.

The (meth)acrylate polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by a normal radical polymerization method. (methyl) The polymerization of the acrylate polymer (A) is preferably carried out by a solution polymerization method according to the desired use of a polymerization initiator. As the polymerization solvent, for example, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, etc. may be mentioned, and two or more kinds may be used in combination.

As a polymerization initiator, an azo compound, an organic peroxide, etc. can be mentioned, You may use 2 or more types together. As the azo compound, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclo Hexane-1-nitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxy Valeronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] and the like.

Examples of organic peroxides include, for example, benzyl peroxide, t-butyl peroxybenzoate, cumene hydrogen peroxide, diisopropyl peroxydicarbonate, and di-n-propyl peroxydicarbonate. , Bis(2-ethoxyethyl) peroxydicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxytrimethyl acetate, peroxy(3,5,5-trimethyl Hexane), dipropylene peroxide, diacetyl peroxide, etc.

Furthermore, in the above-mentioned polymerization step, by formulating a chain transfer agent such as 2-mercaptoethanol, the weight average molecular weight of the obtained polymer can be adjusted.

After the (meth)acrylate polymer (A) is obtained, the active energy ray curable compound (B) is added to the (meth)acrylate polymer (A) solution, and the cross-linking agent (C) according to the desired , The photopolymerization initiator (D), additives, and diluting solvent are mixed thoroughly to obtain the adhesive composition P (coating solution) diluted with the solvent. Furthermore, when any one of the above-mentioned components is used in a solid form, Alternatively, when mixing with other components in an undiluted state causes precipitation, the component may be separately dissolved or diluted with a diluting solvent in advance, and then mixed with other components.

As the above-mentioned dilution solvent, for example, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane and dichloroethane, methanol, ethanol, Alcohols such as propanol, butanol, 1-methoxy-2-propanol, acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone and other ketones, ethyl acetate, butyl acetate, etc. Serosu series solvents such as esters, ethyl Serosu, etc.

The concentration and viscosity of the coating solution prepared in this way are not particularly limited as long as the coating solution is within the coatable range, and can be appropriately selected according to the situation. For example, the concentration of the adhesive composition P is diluted to 10 to 60% by mass. In addition, when obtaining a coating solution, the addition of a dilution solvent etc. is not an essential condition, as long as the adhesive composition P has the viscosity which can apply|coat, the dilution solvent may not be added. At this time, the adhesive composition P becomes a coating solution in which the polymerization solvent of the (meth)acrylate polymer (A) is directly used as a diluting solvent.

(1-7) Manufacturing of adhesive

The active energy ray-curable adhesive can be better obtained by bridging the adhesive composition P. The bridging of the adhesive composition P can usually be performed by heat treatment. In addition, this heating process can also be used as a drying process when volatilizing the coating film of the adhesive composition P applied to a desired target object, such as a dilution solvent.

The heating temperature of the heat treatment is preferably 50 to 150°C, especially 70 to 120°C. In addition, the heating time is preferably 10 seconds to 10 minutes. Especially 50 seconds to 2 minutes is better.

After the heat treatment, if necessary, an aging period of about 1 to 2 weeks can be set at normal temperature (for example, 23° C., 50% RH). When the aging period is required, after the aging period has elapsed, and when the aging period is not required, the adhesive is formed after the heat treatment is completed.

By the above-mentioned heat treatment (and aging), (when the cross-linking agent (C) is included, the (meth)acrylate polymer (A)) is sufficiently bridged via the cross-linking agent (C).

(2) The thickness of the adhesive layer

The thickness of the first adhesive layer 21 and the thickness of the second adhesive layer 22 are preferably 15 μm or more, particularly 30 μm or more, and more preferably 50 μm or more. In addition, the thickness is preferably 300 μm or less, particularly 150 μm or less, and more preferably 100 μm or less. By making the thickness fall within the above-mentioned range, the effects of the above-mentioned step followability and workability can be better exhibited. Furthermore, the thickness of the first adhesive layer 21 and the thickness of the second adhesive layer 22 may be the same or different. For example, from the viewpoint of step followability, it is preferable that the adhesive layer adhered to the side of the body having the step is thicker than the other adhesive layer.

2. Middle layer

The intermediate layer 23 is as described above, and the glass transition temperature is 0°C or more and 60°C or less. From the viewpoint of obtaining excellent workability, the glass transition temperature is preferably 20°C or higher, and more preferably 27°C or higher. On the other hand, from the viewpoint of making the initial step followability excellent, the glass transition temperature is preferably 50°C or less, more preferably 40°C or less, and particularly preferably 30°C or less.

The intermediate layer 23 may be active energy ray non-curable or active energy ray curable. However, the first adhesive layer 21 and the second adhesive layer 22 When at least one of is active energy ray curability, it is preferable that the intermediate layer 23 also has active energy ray curability. This is because the active energy ray-curable adhesive layer and the active energy ray-curable intermediate layer can react with each other at the interface to form a chemical bond. Thereby, the adhesion strength between the adhesive layer and the intermediate layer 23 is improved, and the interlayer peeling is suppressed, so that the double-sided adhesive sheet 2 has better step followability under high-temperature and high-humidity conditions.

Furthermore, the active energy ray curability of the intermediate layer 23 refers to the property of showing relatively small elasticity before the active energy ray is irradiated, and the elasticity is improved by curing it by irradiating the active energy ray after being adhered to the body.

In order to obtain the intermediate layer 23 having the above-mentioned glass transition temperature, the material constituting the intermediate layer 23 contains a resin having a glass transition temperature of 0°C or higher and 60°C or lower (hereinafter sometimes referred to as "resin (E)") as good. That is, the intermediate layer 23 is preferably composed of a resin composition containing the resin (E) (hereinafter may be referred to as "resin composition Q").

(1) Resin composition

(1-1) Resin (E)

When the glass transition temperature of the resin (E) contained in the material (resin composition Q) constituting the intermediate layer 23 is 0° C. or more and 60° C. or less, the glass transition temperature of the intermediate layer 23 itself is likely to fall within the above range. From this viewpoint, the glass transition temperature of the resin (E) is particularly preferably 20°C or higher, and more preferably 30°C or higher. In addition, the glass transition temperature of the resin (E) is particularly preferably 50°C or less, and more preferably 40°C or less.

As the resin (E), vinyl acetate resin, polyolefin resin, etc. can be cited. Among them, the double-sided adhesive sheet 2 has an initial step followability particularly Excellent vinyl acetate resin is preferred. Vinyl acetate resins, in addition to polyvinyl acetate, which is a single polymer of vinyl acetate, can include copolymers of vinyl acetate and other monomers copolymerizable with vinyl acetate, for example, ethylene-vinyl acetate copolymers. Things and so on.

The lower limit of the average molecular weight of the vinyl acetate resin is preferably 10,000 or more, especially 20,000 or more, and more preferably 100,000 or more. By making the lower limit of the weight average molecular weight of the vinyl acetate resin more than the above, the film forming property and processability of the intermediate layer 23 can be improved. In addition, the upper limit of the weight average molecular weight of the vinyl acetate resin is preferably 1 million or less, particularly preferably 700,000 or less, and further preferably 500,000 or less. By setting the upper limit of the weight average molecular weight of the vinyl acetate resin to the above-mentioned or less, the step followability can be further improved.

The resin composition Q preferably contains the above-mentioned resin (E) as the main component. Specifically, it preferably contains 50% by mass or more of the resin (E), particularly preferably contains 60% by mass or more, and contains 80% by mass. % Or more is further better. The resin composition Q may be composed only of the resin (E). On the other hand, when the resin composition Q contains other components (for example, the active energy ray-curable compound (F) or the photopolymerization initiator (G) described later), it may contain 95% by mass or less of the resin (E) Preferably, it is particularly preferable to contain 93% by mass or less, and it is even more preferable to contain 90% by mass or less.

(1-2) Other ingredients

When the intermediate layer 23 is active energy ray curable, the resin composition Q preferably contains an active energy ray curable compound (F) in addition to the above-mentioned resin (E). As active energy ray curable compound (F), it can be used and can be used in the above The active energy ray hardening compound (B) of the active energy ray hardening adhesive is the same active energy ray hardening compound. From the viewpoint of interlayer adhesion, it is particularly preferable to use an active energy ray curable compound of the same kind as the active energy ray curable compound (B) contained in the active energy ray curable adhesive constituting the adhesive layer It is further preferable to use the same active energy ray curable compound as the active energy ray curable compound (B) included in the active energy ray curable adhesive constituting the adhesive layer.

In terms of the content of the active energy ray curable compound (F) of the resin composition Q, from the viewpoint of excellent interlayer adhesion and step followability under high-temperature and high-humidity conditions, 100 parts by mass of the resin (E) is below The limit is preferably 1 part by mass or more, particularly preferably 5 parts by mass or more, and from the viewpoint of making the initial step followability more excellent, 10 parts by mass or more is more preferable. On the other hand, from the viewpoint of not reducing the glass transition temperature of the intermediate layer 23 excessively with the above content, the upper limit is preferably 40 parts by mass or less, particularly preferably 30 parts by mass or less, and 20 parts by mass or less. Further better.

In addition, when curing the active energy ray-curable resin composition Q, when ultraviolet rays are used as the irradiated active energy rays, the resin composition Q preferably further contains a photopolymerization initiator (G). As the photopolymerization initiator (G), the same photopolymerization initiator as the photopolymerization initiator (D) that can be used for the above-mentioned active energy ray curable adhesive can be used.

In the content of the photopolymerization initiator (G) of the resin composition Q, with respect to 100 parts by mass of the active energy ray curable compound (F), the lower limit is preferably 0.1 part by mass or more, especially 1 part by mass or more good. In addition, the upper limit is preferably 30 parts by mass or less, and particularly preferably 10 parts by mass or less.

On the other hand, when the resin composition Q is non-curable with active energy rays, the resin composition Q, in addition to the above-mentioned resin (E), may be included in the first constituent adhesive layer 21 and the second adhesive. The reactive functional group of the (meth)acrylate polymer (A) in the adhesive of the layer 22 (derived from the monomer containing the reactive functional group) is preferably a bridging monomer that forms a bridging structure, and it is further preferred to include The bridging agent forming the bridging structure is particularly preferred. As the bridging monomer, the same functional group as the reactive functional group contained in the (meth)acrylate polymer (A) is preferred. For example, the same functional group as the reactive functional group contained in the (meth)acrylate polymer (A) is used. The monomers containing reactive functional groups are preferably the same monomers. In addition, as the bridging agent, it is preferable to use the same bridging agent (C) in the adhesives constituting the first adhesive layer 21 and the second adhesive layer 22. Furthermore, the adhesive constituting the first adhesive layer 21 and the second adhesive layer 22 may be an active energy ray curable adhesive or an active energy ray non-curable adhesive.

In the above case, the adhesive composition and resin composition Q used to form the first adhesive layer 21 and the second adhesive layer 22 are thermally bridged, and the (meth)acrylate polymer (A) and the bridging monomer are thermally bridged. The body is chemically bonded via the bridging agent (C) in the adhesive composition or the bridging agent in the resin composition Q. Thereby, the adhesion between the first adhesive layer 21 and the intermediate layer 23, the second adhesive layer 22 and the intermediate layer 23 is improved, and the adhesion between the intermediate layer 23 and the first adhesive layer 21 and the second adhesive layer can be suppressed. Interlayer peeling occurred at the interface of 22.

In the resin composition Q, various additives may be added as desired, such as an antistatic agent, an adhesion imparting agent, an oxidation inhibitor, a light stabilizer, a softening agent, a filler, a refractive index adjusting agent, and the like.

In addition, the resin composition Q is expressed in the intermediate layer, and is based on the original In the state after the reaction, the remaining mixture of various components, the components removed in the drying step, for example, the diluent solvent described later, are not included in the adhesive composition Q.

(1-3) Resin composition‧Manufacturing of intermediate layer

The resin composition Q can be produced by adding an active energy ray curable compound (F), a photopolymerization initiator (D), additives, etc., to the resin (E) as desired. When applying the resin composition Q, by adding a dilution solvent as desired, a resin composition Q (coating solution) diluted with a solvent can be obtained.

The intermediate layer 23 can be formed by, for example, applying a coating solution of the resin composition Q and drying it. This drying can usually be performed by heat treatment. The conditions of the heat treatment are the same as the heat treatment conditions in the production of the above-mentioned adhesive.

Furthermore, when the intermediate layer 23 is non-curable with active energy rays, and when the resin composition Q contains the active energy ray curable compound (F), after the coating and drying, it may be further irradiated with active energy rays. The resin composition Q is cured, and this is used as the intermediate layer 23. However, in consideration of the initial level difference followability, it is preferable to bond the display component with the level difference and other display components with the double-sided adhesive sheet 2, and then irradiate the active energy rays to make the intermediate layer 23 (composed of resin Composition Q) hardened.

(2) Thickness of the middle layer

The ratio of the thickness of the intermediate layer 23 to the total thickness of the first adhesive layer 21 and the second adhesive layer 22 is preferably 0.01 or more, especially 0.05 or more, and more preferably 0.15 or more. In addition, the ratio is preferably 2 or less, particularly 1.5 or less, further preferably 1 or less, and most preferably 0.5 or less. By setting the ratio to 0.01 or more, the effects of the step following and processability can be more satisfactorily exhibited. In addition, the thickness of each layer is a value measured in compliance with JIS K7130.

The thickness of the intermediate layer 23 is preferably 5 μm or more, especially 10 μm or more, and more preferably 15 μm or more. In addition, the thickness is preferably 100 μm or less, particularly preferably 70 μm or less, and more preferably 50 μm or less. By making the thickness fall within the above-mentioned range, the above-mentioned step-following and workability effects can be exhibited more satisfactorily.

3. Peel off the plate

The peeling plates 31 and 32 are used to protect the contact surface of the double-sided adhesive plate 2 until the time of use. When the double-sided adhesive plate 2 is used, it will be peeled off. Regarding the double-sided pressure-sensitive adhesive sheet 1 with a release sheet of the present embodiment, one of the release sheet pieces 31 and 32 is not necessary.

As the release sheet 31, 32, it is possible to use, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, Polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene‧( Meth) acrylic copolymer film, ethylene‧(meth)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. In addition, such bridging films can be used. Furthermore, these laminated films may also be used.

It is preferable to apply a peeling treatment to the peeling surfaces of the peeling sheets 31 and 32 (especially the surface contacting the double-sided adhesive sheet 2). As for peeling treatment Examples of the release agent include alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax release agents. In addition, among the peeling plates 31 and 32, one of the peeling plates is made as a heavy peeling type peeling plate with a large peeling force, and the other peeling plate is made as a light peeling type peeling plate with a small peeling force. good.

The thickness of the peeling sheet pieces 31 and 32 is not particularly limited, but is usually about 20 to 150 μm.

4. The physical properties of the adhesive sheet, etc.

The total thickness of the double-sided adhesive sheet 2 is preferably 50 μm or more, especially 100 μm or more, and more preferably 150 μm or more. In addition, the total thickness is preferably 600 μm or less, particularly 400 μm or less, and more preferably 300 μm or less. By making the total thickness of the double-sided adhesive sheet 2 fall within the above-mentioned range, the above-mentioned step-following and processability effects can be better exhibited.

The lower limit of the Young's modulus of the double-sided adhesive sheet 2 is preferably 0.01 MPa or more, especially 0.5 MPa or more, and further preferably 5 MPa or more. When the Young's modulus is more than the above lower limit, the film strength of the double-sided adhesive sheet 2 can be made high, and the workability of the double-sided adhesive sheet 1 with a release sheet can be improved. In addition, the upper limit of the above Young's modulus is preferably 100Mpa or less, particularly preferably 50Mpa or less, and further preferably 20Mpa or less. When the Young's modulus is less than the above upper limit, the flexibility of the double-sided adhesive sheet 2 can be improved, and the initial step followability of the double-sided adhesive sheet 2 can be more excellent. In addition, the measuring method of this Young's modulus is as shown in the test example mentioned later.

5. Manufacturing of double-sided adhesive plates

As an example of the production of a double-sided adhesive sheet 1 with a release sheet, the adhesive composition P is applied to the release surface of one release sheet 31 Liquid, heat treatment is performed to thermally bridge the adhesive composition P to form a coating layer, and a release sheet 31 with a coating layer of the adhesive composition P is obtained. In addition, on the peeling surface of the other peeling sheet 32, the coating liquid of the adhesive composition P is applied, and the adhesive composition P is heated to bridge the adhesive composition P to form a coating layer to obtain an adhesive composition. The release sheet 32 of the coating layer of the material P. Furthermore, the coating liquid of the above-mentioned resin composition Q is apply|coated to the peeling layer of another peeling board sheet, and it is dried, and the peeling board sheet with the intermediate layer 23 is obtained.

Next, the peeling sheet 31 with the coating layer of the adhesive composition P and the peeling sheet with the intermediate layer 23 are pasted so that the two layers are in contact with each other, and the peeling sheet is peeled from the intermediate layer 23. Next, the intermediate layer 23 and the release sheet 32 to which the coating layer of the adhesive composition P is attached are adhered so that the two layers are in contact with each other. When the aging period is required, leave the aging period. When the aging period is not required, leave it as it is. The coating layer of the adhesive composition P on one side of the above-mentioned laminate becomes the first adhesive layer 21, and the coating layer of the adhesive composition P on the other side is applied. The cloth layer becomes the second adhesive layer 22. With this, a double-sided adhesive sheet 2 composed of a first adhesive layer 21, an intermediate layer 23, and a second adhesive layer 22 is obtained by sandwiching the peeling sheets 31 and 32, and a double-sided adhesive with a peeling sheet is obtained. Plate 1. In addition, the maturation of the coating layer of the adhesive composition may be performed after bonding the coating layer of the adhesive composition into three layers as described above, or may be performed before bonding.

The method of applying the coating liquid of the adhesive composition P and the coating liquid of the resin composition Q can be used, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, and a mold Coating method, gravure coating method, etc.

Regarding the double-sided adhesive sheet 1 with a release sheet of the present embodiment, since the workability is good, the double-sided adhesive sheet with the release sheet is cut during processing. In the case of the sheet 1, it is possible to suppress the problem of the adhesive overflowing on the cut surface and adhering to the blade.

[Display body]

As shown in FIG. 2, regarding the display body 4 of this embodiment, the structure includes: a first display body constituent member 51 (a display body constituent member) having a step at least on the surface of the adhered side; and a second display body constituent member 52 (other display body constituent members); located between these, the double-sided adhesive sheet 2 that bonds the first display body constituent member 51 and the second display body constituent member 52 to each other. In the display body 4 of this embodiment, the first display body constituent member 51 has a level difference on the surface of the double-sided adhesive sheet 2 side, specifically, a level difference caused by the printed layer 6.

When any one of the first adhesive layer 21, the second adhesive layer 22, and the intermediate layer 23 of the double-sided adhesive sheet 2 is curable with active energy rays, on the double-sided adhesive sheet 2 of the above-mentioned display body 4, The double-sided adhesive sheet 2 of the above-mentioned double-sided adhesive sheet 1 with a release sheet is cured by irradiating active energy rays to become a hardened double-sided adhesive sheet 2'. Here, the term “active energy rays” refers to those having energy quantum in electromagnetic waves or charged particle rays. Specifically, ultraviolet rays, electron beams, and the like can be cited. Among the active energy rays, ultraviolet rays, which are easy to operate, are particularly preferred.

Ultraviolet rays can be irradiated by high-pressure mercury lamps, fusion H lamps, xenon lamps, etc. The amount of ultraviolet irradiation is preferably about ^{50~1000mW/cm 2.} Further, the light amount to 50 ~ 10000mJ / cm ² preferably, to 80 ~ 5000mJ / cm ² is more preferably, 200 ~ 2000mJ / cm ² is particularly preferred. On the other hand, the irradiation of the electron beam can be carried out by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10~1000krad.

The irradiation of the active energy rays of the double-sided adhesive sheet 2 is preferably After the first display body constituent member 51 and the second display body constituent member 52 are adhered to each other by the double-sided adhesive sheet 2, the first display body constituent member 51 and the second display body constituent member 52 can be worn through Through the active energy ray components.

When the double-sided adhesive sheet 2 is irradiated with active energy rays, the active energy ray curable compound (B) in the first adhesive layer 21, the active energy ray curable compound (B) in the second adhesive layer 22, At least one of the active energy ray-curable compound (F) in the intermediate layer 23 polymerizes and hardens. The hardened double-sided adhesive sheet 2'formed by irradiation hardening of active energy rays has excellent step followability under high temperature and high humidity. In addition, when at least one of the first adhesive layer 21 and the second adhesive layer 22 and the intermediate layer 23 are active energy ray curable, the active energy ray curable compound (B) and the active energy ray curable compound ( F) The active energy ray irradiation reacts with each other to chemically bond, so that the adhesive layer and the intermediate layer 23 can improve the adhesiveness of the active energy ray curability, while suppressing the adhesion between the adhesive layer and the intermediate layer 23 Interlayer peeling occurs at the interface.

As the display body 4, for example, a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, electronic paper, etc. can be cited, and it may be a touch panel. In addition, the display body 4 may be a member constituting a part of these.

In addition to the glass plate, plastic plate, etc., the first display body constituent member 51 is preferably a protective plate composed of a laminate including these. At this time, the printed layer 6 is generally formed on the double-sided adhesive sheet 2 side of the first display body constituent member 51 and formed in a frame shape.

As the above-mentioned glass plate, there is no particular limitation. For example, chemically strengthened glass, alkali-free glass, quartz glass, soda-lime glass, barium-containing ‧ Strontium glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass, etc. The thickness of the glass plate is not particularly limited, but is usually 0.1 to 5 mm, preferably 0.2 to 2 mm.

It does not specifically limit as said plastic board, For example, an acrylic board, a polycarbonate board, etc. can be mentioned. The thickness of the plastic plate is not particularly limited, and is usually 0.2 to 5 mm, preferably 0.4 to 3 mm.

Furthermore, various functional layers (transparent conductive film, metal layer, silicon dioxide layer, hard coating, anti-glare layer, etc.) can also be provided on one or both sides of the glass plate and plastic plate, and optical layers can also be laminated member. In addition, the transparent conductive film and the metal layer can also be patterned.

The second display component 52 is an optical member and a display module (for example, a liquid crystal (LCD) module, a light-emitting diode (LED) module, an organic electro-optical device) that should be adhered to the first display component 51 A light-emitting (organic EL) module, etc.) is preferably an optical member that is a part of the display module, or a laminate including the display module.

As the above-mentioned optical member, for example, a scattering prevention film, a polarizing plate (polarizing film), a polarizer, a retardation film (retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film , Diffusion film, transflective film, transparent conductive film, etc. As the anti-scattering film, a hard coat film formed by forming a hard coat on one side of a base film, etc. can be exemplified.

The material constituting the printing layer 6 is not particularly limited, and conventional materials for printing can be used. The thickness of the printed layer 6, that is, the lower limit of the height of the step, is preferably 3μm or more, more preferably 5μm or more, and 10μm or more as Particularly good, 50μm or more is the best. By setting the lower limit value to be more than the above, it is possible to sufficiently ensure the concealment of the electrical wiring and the like from the viewer's side. In addition, the upper limit is preferably 200 μm or less, more preferably 150 μm or less, particularly preferably 100 μm or less, and even more preferably 80 μm or less. By making the upper limit value below the above, it is possible to prevent the double-sided pressure-sensitive adhesive sheet 2 from deteriorating the step followability of the printed layer 6.

The above-mentioned display body 4 is manufactured. As an example, one of the release sheets 31 of the double-sided adhesive sheet 1 with the release sheet is peeled off, and the exposed adhesive surface of the double-sided adhesive sheet 2 is pasted on the first The surface of the display component 51 on the side where the printed layer 6 exists.

After that, the other release sheet 32 is peeled from the double-sided adhesive sheet 1 to which the release sheet is attached, and the exposed adhesive surface of the double-sided adhesive sheet 2 is bonded to the second display constituent member 52. In addition, as another example, the bonding order of the first display body constituent member 51 and the second display body constituent member 52 may be reversed.

When the above-mentioned bonding is performed, the double-sided adhesive sheet 1 with the release sheet is heated to soften the intermediate layer 23 in the double-sided adhesive sheet 2. The heating temperature may be any temperature that can soften the intermediate layer 23, usually 25°C or more and 70°C or less, especially 30°C or more and 60°C or less, and further 35°C or more and 50°C or less. Better. By the above heating, the entire double-sided adhesive sheet 2 is excellent in flexibility, and the initial step followability is excellent, so that the occurrence of voids or floating near the step due to the printed layer 6 can be suppressed.

Next, when any one of the first adhesive layer 21, the second adhesive layer 22, and the intermediate layer 23 of the double-sided adhesive sheet 2 is curable with active energy rays, the double-sided adhesive sheet 2 is irradiated with active energy rays , Hardenable layer of active energy rays hardening.

In the above display 4, when at least one of the first adhesive layer 21, the second adhesive layer 22, and the intermediate layer 23 of the double-sided adhesive sheet 2 is cured by irradiation with active energy rays, after curing The double-sided adhesive sheet 2'has excellent step followability even under high temperature and high humidity conditions. Therefore, even when the display body 4 is placed under high temperature and high humidity conditions (for example, 85° C., 85% RH, 72 hours), it is still possible to suppress the occurrence of bubbles, floating, peeling, etc. near the step. In addition, when at least one of the first adhesive layer 21 and the second adhesive layer 22 and the intermediate layer 23 are cured by active energy rays, it is also possible to suppress the occurrence of interlayer at the interface between the adhesive layer and the intermediate layer 23. Peel off.

The embodiments described above are described in order to facilitate the understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above-mentioned embodiment includes all design changes or equivalents belonging to the technical scope of the present invention.

For example, one of the peeling sheets 31 and 32 of the double-sided adhesive sheet 1 with a peeling sheet may be omitted, and a desired optical member may be laminated instead of the peeling sheet 31 and/or 32. Furthermore, between the first adhesive layer 21 and/or the second adhesive layer 22 of the double-sided adhesive sheet 2 and the intermediate layer 23, other layers may also be present. On the outside of the adhesive layer 21 and/or the second adhesive layer 22 (the side of the release sheet 31, 32), other layers may be further present.

In addition, the first display body constituent member 51 may have a step other than the printed layer 6. In addition, not only the first display component 51 but the second display component 52 may have a step on the double-sided adhesive sheet 2 side.

[Example]

Hereinafter, the present invention will be explained in more detail through examples, but the present invention is not limited to these examples.

[Example 1]

(1) Production of laminated body with first adhesive layer or second adhesive layer

(1-1) Preparation of (meth)acrylate polymer (A)

Copolymerize 65 parts by mass of 2-ethylhexyl acrylate, 5 parts by mass of N-propenylmorpholine, 15 parts by mass of isobornyl acrylate, and 15 parts by mass of 2-hydroxyethyl acrylate to prepare (meth)acrylic acid Ester polymer (A). The molecular weight of the (meth)acrylate polymer (A) was measured by the method described later, and the weight average molecular weight (Mw) was 500,000.

(1-2) Preparation of adhesive composition P

100 parts by mass of the (meth)acrylate polymer (A) obtained in the above step (1-1) (solid content conversion value; the same below) and 5 parts by mass are used as the ε of the active energy ray curable compound (B) -Caprolactone denatured tris(2-propenoxyethyl) isocyanurate (manufactured by Shinnakamura Chemical Co., Ltd., product name "NK ESTER A-9300-1CL"), 0.15 parts by mass as a bridging agent (C) Toluene diisocyanate-based bridging agent (manufactured by TOYO CHEM, product name "BHS-8515"), and 0.5 parts by mass of benzophenone and 1-hydroxycyclohexyl phenyl ketone as the photopolymerization initiator (D) : 1 mass ratio of the mixture (manufactured by BASF, product name "IRGCURE 500") was mixed, fully stirred, and diluted with methyl ethyl ketone to obtain a coating solution of the adhesive composition P.

(1-3) Production of laminated body

The coating solution of the adhesive composition P obtained in the above step (1-2) was coated with a knife coater, and the polyethylene terephthalate was peeled off with a silicone-based release agent After the peeling treatment surface of the heavy peeling type peeling sheet (manufactured by LINTEC Corporation, product name "SP-PET752150") of one side of the glycol ester film, the coating layer was formed by heat treatment at 90°C for 1 minute. Then, on the coating layer, a light-peelable release sheet (manufactured by LINTEC Corporation, product name "SP-PET382120") is attached to one side of the polyethylene terephthalate film with a silicone-based release agent. The peeling treatment surface. After that, it was aged for 7 days under the conditions of 23°C and 50% RH to obtain a heavy peelable peelable sheet/first adhesive layer (active energy ray curability, thickness: 100μm)/light peelable peelable sheet The first layered body composed of the composition.

In addition, in the same manner as described above, a second laminated body composed of a heavy peelable release sheet/second adhesive layer (active energy ray curability, thickness: 50 μm)/lightly peelable release sheet was produced.

The thickness of the above-mentioned adhesive layer is a value measured using a constant pressure thickness measuring device (manufactured by TECLOCK, product name "PG-02") in compliance with JIS K7130.

(2) Production of laminated body with intermediate layer

(2-1) Preparation of resin composition Q

100 parts by mass of polyvinyl acetate (VAc, weight average molecular weight (Mw): 20,000, Tg: 32°C) as resin (E), and 10 parts by mass of ε-hexyl as active energy ray curable compound (F) Lactone-modified tris(2-propenoxyethyl) isocyanurate (manufactured by Shinnakamura Chemical Co., Ltd., product name "NK ESTER A-9300-1CL"), 1 part by mass as a photopolymerization initiator (G) A mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name "IRGACURE 500") at a mass ratio of 1:1, mixed well, and diluted with methyl ethyl ketone to obtain resin composition Q Coating solution.

(2-2) Production of laminated body

Using the coating solution of the resin composition Q obtained in the above step (2-1), except that it is not matured, in the same manner as the above-mentioned adhesive composition P, a heavy-peelable release sheet/intermediate layer (active energy ray Hardenability, thickness: 10μm)/light-peelable release sheet composition composed of the third laminate.

Here, the above-mentioned weight average molecular weight (Mw) is a weight average molecular weight in terms of polystyrene measured by a gel permeation chromatograph (GPC) under the following conditions (GPC measurement).

<Measurement conditions>

‧GPC measuring device: manufactured by TOSO, HLC-8020

‧GPC string (pass in the following order): made by TOSO

TSK guard column HXL-H

TSK gel GMHXL(×2)

TSK gel G2000HXL

‧Measuring solvent: Tetrahydrofuran

‧Measuring temperature: 40℃

(3) Production of double-sided adhesive plates with release plates

While peeling the lightly peelable release sheet from the first laminate obtained in (1) above, peel off the lightly peelable release sheet from the third laminate obtained in (2) above to make the exposed first adhesive The agent layer and the intermediate layer are bonded in contact with each other, and the re-peelable release sheet is peeled from the intermediate layer. Next, the lightly peelable release sheet is peeled from the second laminate obtained in (1) above, and the exposed second adhesive layer and the intermediate layer are bonded in contact with each other to obtain a first adhesive layer, The double-sided adhesive sheet composed of the intermediate layer and the second adhesive layer is sandwiched by two heavy-peelable peeling sheets. The double-sided adhesive sheet with the peeling sheet is formed.

[Example 2]

Except that the compounding amount of the active energy ray-curable compound (F) was changed to 5 parts by mass and the photopolymerization initiator (G) was changed to 0.5 parts by mass, the resin composition Q was prepared in the same manner as in Example 1. The solution is applied to produce a third laminate. Except having used this 3rd laminated body, it carried out similarly to Example 1, and produced the double-sided adhesive sheet with a peeling sheet.

[Example 3]

Except having changed the thickness of the intermediate layer to 25 μm, in the same manner as in Example 1, a double-sided pressure-sensitive adhesive sheet with a release sheet was produced.

[Example 4]

When forming the intermediate layer, use 100 parts by mass of polyvinyl acetate (VAc, weight average molecular weight (Mw): 200,000, Tg: 32°C) instead of polyvinyl acetate (VAc, weight average molecular weight ( Mw): 20,000, Tg: 32°C) except for 100 parts by mass, in the same manner as in Example 3, a double-sided adhesive sheet with a release sheet was produced.

[Example 5]

Except having changed the thickness of the intermediate layer to 50 μm, in the same manner as in Example 1, a double-sided pressure-sensitive adhesive sheet with a release sheet was produced.

[Example 6]

Except for not preparing the active energy ray-curable compound (F) and the photopolymerization initiator (G), in the same manner as in Example 1, a coating solution of the resin composition Q was prepared to produce a third laminate. Except having used this 3rd laminated body, it carried out similarly to Example 1, and produced the double-sided adhesive sheet with a peeling sheet.

[Example 7]

Except that the compounding amount of the active energy ray curable compound (F) was changed to 30 parts by mass and the compounding amount of the photopolymerization initiator (G) was changed to 3 parts by mass, the resin composition was prepared in the same manner as in Example 1. A coating solution of the substance Q was prepared to produce a third layered product. Except having used this 3rd laminated body, it carried out similarly to Example 1, and produced the double-sided adhesive sheet with a peeling sheet.

[Comparative Example 1]

While peeling the lightly peelable release sheet from the first laminate obtained in (1) of Example 1, the lightly peelable release sheet was peeled from the second laminate obtained in (1) of Example 1, at the same time, The exposed first adhesive layer and the second adhesive layer are bonded in contact with each other, and the adhesive layer composed of the first adhesive layer and the second adhesive layer is sandwiched by two heavy peelable release plates. Adhesive plates made. Except having used this adhesive sheet, it carried out similarly to Example 1, and produced the double-sided adhesive sheet with a peeling board.

[Comparative Example 2]

The lightly peelable release sheet was peeled from the first laminate obtained in (1) of Example 1, and the exposed first adhesive layer was bonded to a polyethylene terephthalate film (thickness : 12μm, Tg: 80°C). Next, the lightly peelable release sheet was peeled from the second laminate obtained in (1) of Example 1, and the exposed second adhesive layer and the polyethylene terephthalate film were brought into contact with each other. Adhesive method to obtain a double-sided adhesive sheet composed of the first adhesive layer, the intermediate layer (ethylene terephthalate film) and the second adhesive layer, which is sandwiched by two heavy peelable release sheets. The double-sided adhesive sheet with peel-off sheet.

[Test Example 1] (Measurement of Glass Transition Temperature)

The glass transition temperature of the intermediate layer used in the examples and comparative examples (Tg) is measured using a differential scanning calorimetry device (manufactured by TA INSTRUMENT JAPAN, product name "DSC Q2000") under the conditions of a heating and cooling rate of 20°C/min. The results are shown in Table 1.

[Test Example 2] (Measurement of Young's Modulus of Adhesive Layer)

The double-sided adhesive sheets produced in the examples and comparative examples were laminated in plural to a thickness of about 1000 μm, and cut into test pieces of 10 mm×70 mm. Then, in compliance with JIS K7161: 1994, the Young's modulus at 23° C. and 50% RH was measured. Specifically, the above-mentioned test piece was tested using a universal tensile tester (manufactured by ORIENTEC, product name "Tensilon RTA-T-2M") with a clamp spacing of 20 mm, and then a tensile test was performed at a speed of 200 mm/min. Measure Young's modulus (unit: MPa). The results are shown in Table 1.

[Test Example 3] (Evaluation of the followability of the step difference)

Screen printing on the surface of a glass plate (product name "Corning Glass EAGLE XG" made by NSG PRECISION, 90mm in length × 50mm in width × 0.5mm in thickness) in a frame shape (outer shape: length 90mm × width 50mm, line width 5mm) UV-curable ink (manufactured by Teikoku Ink, product name "POS-911 ink"). Next, irradiate ultraviolet rays (80W/cm ² , 2 metal halide mercury lamps, lamp height 15cm, conveyor speed 10~15m/min) to harden the above-mentioned ultraviolet curable ink after printing, and produce a step difference caused by printing ( The height of the step: 60μm) of the glass plate with the step.

Peel off the release sheet on the second adhesive layer (thickness 50μm) side from the double-sided adhesive sheet with release sheet obtained in the examples and comparative examples, and stick the exposed adhesive layer on the adhesive layer Polyethylene terephthalate (PET) film (manufactured by Toyobo, product name "PET A4300", thickness: 100μm) The easy-adhesive layer. Next, the release sheet on the side of the first adhesive layer (100 μm in thickness) was peeled off to expose the adhesive layer. Then, using a laminator (manufactured by FUJIPLA, product name "LPD3214"), the adhesive layer was used to cover the printed surface of the frame shape, and the laminate was laminated on a glass plate with steps. After that, autoclave treatment was carried out for 30 minutes under the conditions of 50°C and 0.5 MPa. At this stage, visually confirm whether there are bubbles in the double-sided adhesive sheet (especially near the step caused by the printed layer). As a result, those with no bubbles at all were evaluated as ⊚, those with less than 10 bubbles were evaluated as ○, and those with more than 10 bubbles were evaluated as × (evaluation of initial stage difference followability). The results are shown in Table 1.

Next, the above-mentioned double-sided adhesive sheet was irradiated with ultraviolet light under the following ultraviolet irradiation conditions through the PET film to cure the double-sided adhesive sheet.

<Ultraviolet radiation conditions>

‧Using UV conveyor system made by EYE GRAPHICS

‧Illuminance 200mW/cm ² , light intensity 1000mJ/cm ²

‧UV illuminance‧Light meter uses "UVPF-36" made by EYE GRAPHICS

The laminated body of the double-sided adhesive sheet cured as described above was stored for 72 hours under high temperature and high humidity conditions of 85° C. and 85% RH. After that, visually confirm whether there are bubbles in the double-sided adhesive sheet (especially near the step caused by the printed layer). As a result, those with no bubbles at all were evaluated as ⊚, those with 10 or less bubbles were evaluated as ○, and those with more than 10 bubbles were evaluated as × (evaluation of poor followability under high-temperature and high-humidity conditions). The results are shown in Table 1. In addition, regarding the adhesive sheet of Example 6, although the number of bubbles was 10 or less, interlayer peeling between the adhesive layer and the intermediate layer was seen near the step (evaluation: △). The results are shown in Table 1.

[Test Example 4] (Evaluation of Workability)

<A method>

The double-sided adhesive sheets with release sheets obtained in the Examples and Comparative Examples were cut with an automatic cutter (manufactured by Ogino Manufacturing Co., Ltd., product name "Super Cutter OSS-PN1 Type N-L"). This cutting is performed 10 times. The cut surface (length: 100 mm) of the cut adhesive sheet was visually confirmed, and the workability was evaluated based on the following criteria. The results are shown in Table 1.

⊚: No adhesive spilled out of 10 times.

○: In 10 times, there was no adhesive overflow in 5-9 times.

△: 1 to 4 times out of 10 times, there was no overflow of the adhesive.

×: Out of 10 times, the adhesive overflowed in 10 times.

<Method B>

The double-sided adhesive sheet with release sheet obtained in the Examples and Comparative Examples was cut into a length of 100 mm × a width of 100 mm. Place the cut double-sided adhesive sheet with the release sheet on a horizontal table with the release sheet on the second adhesive layer (thickness 50μm) side facing upwards, and place the first adhesive layer ( The release sheet on the side (thickness 100 μm) is fixed on the table with an adhesive.

Next, it was cut longitudinally at a position of 50 mm in width, and cut with a utility knife to before the lowermost release sheet (cut to the position of the first adhesive layer). After that, only one side of the peeling plate piece on the surface side of the split was removed. In this way, half of the surface is covered with the peeling plate, and the other half is exposed to the double-sided adhesive plate of the second adhesive layer.

Furthermore, the adhesive tape (manufactured by LINTEC Corporation, product name "PET50(A)PL SHIN 8LK") with a length of 100mm x a width of 100mm is cut to make The adhesive surface is attached to the entire surface of the double-sided adhesive plate in such a way that the adhesive surface contacts the above-mentioned double-sided adhesive plate. In this bonding, sufficient pressure is applied from the adhesive tape to prevent air bubbles from remaining at the interface between the above-mentioned adhesive surface and the double-sided adhesive sheet.

Finally, peel off the pasted adhesive tape from the double-sided adhesive sheet. Thereby, the double-sided adhesive sheet of the part where the peeling sheet remains on the surface, and the double-sided adhesive sheet remaining on the lowermost peeling sheet, exposing the part of the second adhesive layer, together with the adhesive tape, from the lowermost layer of the adhesive sheet Peel the board to remove. Do this job 10 times. The cross section (length: 100 mm) of the double-sided pressure-sensitive adhesive sheet that appeared in this way was visually confirmed, and the workability was evaluated based on the following criteria. The results are shown in Table 1.

◎: There was no overflow of the adhesive in 10 times.

○: In 10 times, there was no adhesive overflow in 5-9 times.

△: 1 to 4 times out of 10 times, there was no overflow of the adhesive.

×: Out of 10 times, the adhesive overflowed in 10 times.

It can be seen from Table 1 that the double-sided adhesive sheets obtained from the examples have excellent step-following properties in the initial stage and under high-temperature and high-humidity conditions, as well as good processability. it is good.

【Industrial Profitability】

The double-sided adhesive sheet of the present invention can be suitably used for bonding, for example, a protective plate having a step difference and a desired display body constituent member.

1‧‧‧Double-sided adhesive sheet with peel-off sheet

2‧‧‧Double-sided adhesive plate

21‧‧‧The first adhesive layer

22‧‧‧Second adhesive layer

23‧‧‧Middle floor

31、32‧‧‧Peeling plate

Claims (7)

A display body characterized in that it is obtained by: a display body constituent member; other display body constituent members; and a double-sided adhesive sheet for bonding the above-mentioned one display body constituent member and the above-mentioned other display body constituent members to each other. A display body constituent member is a glass plate, a plastic plate, or a laminated body including a glass plate or a plastic plate with a step at least on the surface to be stuck, and the above-mentioned other display body constituent members are a display body module or include a display body The laminated body of the module, the above-mentioned double-sided adhesive sheet, includes: a first adhesive layer as an outer layer on one surface side; a second adhesive layer as an outer layer on the other surface side; and the above-mentioned first adhesive layer In the intermediate layer between the adhesive layer and the second adhesive layer, the glass transition temperature of the intermediate layer is 0°C or more and 60°C or less. The display body described in claim 1, wherein the first adhesive layer and the second adhesive layer of the double-sided adhesive sheet are formed by curing active energy rays. The display body according to the first item of the scope of patent application, wherein the intermediate layer of the double-sided adhesive sheet is formed by curing active energy rays. The display body as described in item 3 of the scope of patent application, wherein the intermediate layer of the double-sided adhesive sheet is a resin containing a resin having a glass transition temperature of 0°C or more and 60°C or less, and active energy ray curable components The active energy rays of the composition are hardened. The display body described in item 1 of the scope of patent application, wherein the Young's modulus of the double-sided adhesive sheet is 0.01 MPa or more and 100 MPa or less. The display body described in claim 1, wherein the ratio of the thickness of the intermediate layer of the double-sided adhesive sheet to the total thickness of the first adhesive layer and the second adhesive layer is 0.05 or more, 2 the following. A method for manufacturing a display body, which is the method for manufacturing a display body as described in any one of items 2 to 4 in the scope of the patent application: manufacturing a display body constituent member and other display body constituent members through the above-mentioned double-sided adhesive sheet A laminate formed by bonding the sheets; the double-sided adhesive sheet of the laminate is irradiated with active energy rays to harden the double-sided adhesive sheet.

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