TW201819571A - Active energy ray curable adhesive sheet and laminate which are excellent in level difference followability, resistance to moist heat whitening, durability and blister resistance - Google Patents

Abstract

The present invention provides an active energy ray curable adhesive sheet having an adhesive layer excellent in level difference followability, resistance to moist heat whitening, durability and blister resistance, and also provides a laminate. To solve the problem, there is provided an active energy ray curable adhesive sheet 1 which contains an adhesive sheet 1 with an active energy ray curable adhesive layer 11. The ratio of an energy storage modulus at 23 DEG C, after irradiating active energy ray to the adhesive layer 11, to an energy storage modulus at 23 DEG C, before irradiating active energy ray to the adhesive layer 11, is 1.1 to 10. Both sides of the adhesive layer 11 are sandwiched between two pieces of alkali-free glass with a thickness of 1.1 mm, and a laminate obtained by irradiating the active energy ray through the glass on one side thereof is stored under a moist heat condition of 85 DEG C and 85% RH for 240 hours. Then, from the value determined by subtracting a haze value (%) before the moist heat condition from a haze value (%) taken out at 23 DEG C and 50% RH at normal temperature and humidity, the increase in haze value after the moist heat condition is less than 5 points.

Description

   Active energy ray-curable adhesive sheet and laminated body   

The present invention relates to an adhesive sheet of an adhesive layer having an active energy ray curability, and a laminated body obtained by using the adhesive layer of the adhesive sheet.

In recent years, various mobile electronic devices such as mobile phones and tablet terminals are equipped with displays using display modules such as liquid crystal elements, light emitting diodes (LED elements), and organic plated cold light (organic EL) elements.

In such a display, a protective panel is usually formed on the surface side of the display module. Between the protective panel and the display module, when the protective panel is deformed due to external force, a gap is also formed, so that the deformed protective panel does not touch the display module.

However, as mentioned above, if there is an air layer, the refractive index difference between the protective panel and the air layer, and the light reflection loss caused by the refractive index difference between the air layer and the display module are large. problem.

Therefore, some studies have proposed to improve the picture quality of the display by filling the gap between the protective panel and the display module with an adhesive layer. However, the display module side of the protective panel may have a frame-shaped printed layer as unevenness. If the adhesive layer does not follow the unevenness, the adhesive layer floats from the vicinity of the unevenness, and thus, a reflection loss of light occurs. Therefore, the above-mentioned adhesive layer is required to have unevenness followability.

In order to solve the above-mentioned problems, Patent Document 1 describes an adhesive layer for filling a gap between a protective panel and a display module, and a shear storage modulus (G ') at 25 ° C and 1 Hz is 1.0 × 10 ⁵ Pa or less. In addition, the adhesive layer has a gel fraction of 40% or more.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-97070

In Patent Document 1, it is intended to improve the unevenness followability by reducing the storage modulus at room temperature in the adhesive layer. However, if the storage modulus at room temperature is lowered as described above, the storage modulus at high temperature will be excessively reduced, causing problems under durable conditions. For example, after the high-temperature and high-humidity conditions are implemented, when the temperature is returned to normal temperature and normal humidity, problems such as whitening of the adhesive layer or generation of bubbles near the unevenness may occur.

In addition, as the above-mentioned protective panel, a glass plate is generally used, but in recent years, a plastic plate is sometimes used in accordance with requirements such as thinning and weight reduction. In a high-temperature environment, gas (deaeration) may occur from the plastic plate. In the case of using such a plastic plate, due to the above-mentioned degassing, air bubbles may be generated between the plastic plate and the adhesive layer, and they may float or peel (blister).

The present invention has been made in view of such a situation, and an object thereof is to provide an active energy ray-curable adhesive having an adhesive layer that is excellent in unevenness followability and also excellent in moist heat whitening resistance, durability, and blister resistance. Sheet and laminated body.

In order to achieve the above object, first, the present invention provides an active energy ray-curable adhesive sheet, which is an adhesive sheet containing an active energy ray-curable adhesive layer, and is characterized in that the adhesive layer is irradiated onto the adhesive layer. The ratio of the storage modulus at 23 ° C after the active energy ray to the storage modulus at 23 ° C before the active energy ray is irradiated onto the adhesive layer is 1.1 to 10; The laminated body obtained by holding an alkali-free glass having a thickness of 1.1 mm, and irradiating the glass through one side with active energy rays was stored at 85 ° C and 85% RH for 240 hours in a humid heat condition, and thereafter at 23 ° C and 50 ° C. The haze value (%) when taken out at normal temperature and normal humidity of% RH minus the haze value (%) before the above-mentioned wet heat condition, and the increase in the haze value after the wet heat condition is less than 5.0 points (Invention 1).

Secondly, the present invention provides an active energy ray-curable adhesive sheet, which is an adhesive sheet containing an active energy ray-curable adhesive layer, and is characterized in that after the active energy ray is irradiated to the adhesive layer, The storage modulus at 85 ° C is 1.1 ~ 10 compared to the storage modulus at 85 ° C before the active energy ray is irradiated onto the adhesive layer; the thickness of the two sides of the adhesive layer is 1.1 mm with two pieces. The laminated body obtained by holding an alkali-free glass and irradiating the active energy ray through one side of the glass was stored in a humid and hot condition at 85 ° C and 85% RH for 240 hours, and then from normal temperature and normal temperature at 23 ° C and 50% RH. The value of the haze value (%) at the time of taking out under wet is subtracted from the value of the haze value (%) before the above-mentioned wet heat condition, and the increase in the haze value after the wet heat condition is less than 5.0 points.

In the above inventions (Inventions 1, 2), it is preferable that the storage modulus of the adhesive layer at 23 ° C before irradiation with active energy rays is 0.01 to 0.2 MPa (Invention 3).

In the above inventions (Inventions 1 to 3), after the adhesive layer is irradiated with active energy rays, the storage modulus at 23 ° C is preferably 0.02 to 2 MPa (Invention 4).

In the above inventions (Inventions 1 to 4), the storage modulus of the adhesive layer at 85 ° C before irradiation with the active energy ray is preferably 0.01 to 0.1 MPa (Invention 5).

In the above inventions (Inventions 1 to 5), the storage modulus of the adhesive layer at 85 ° C after irradiation with active energy rays is preferably 0.02 to 0.5 MPa (Invention 6).

In the above inventions (Inventions 1 to 6), the thickness of the adhesive layer is preferably 50 to 400 μm (Invention 7).

In the above invention (Invention 1 to Invention 7), the adhesive sheet includes two release sheets, and the adhesive layer is preferably sandwiched by the release sheet so as to contact the release surfaces of the two release sheets (Invention 8). ).

Third, the present invention provides a laminated body, which is characterized in that it includes two rigid plates and an adhesive layer sandwiched by the two rigid plates, and the adhesive layer is directed to the adhesive sheet (invention 1 ~ Invention 8) The adhesive layer is cured by irradiating active energy rays (Invention 9).

In the above invention (Invention 9), it is preferable that at least one of the hard plates has unevenness on a surface on the side of the adhesive layer (Invention 10).

In the said invention (invention 10), it is preferable that the said unevenness | corrugation is the unevenness | corrugation based on the presence or absence of a printing layer (invention 11).

In the above invention (Invention 9 to Invention 11), at least one of the hard plates preferably includes a polarizing plate (Invention 12).

In the above invention (Invention 9 to Invention 12), at least one of the hard plates preferably includes a plastic plate (Invention 13).

In the above invention (Invention 9 to Invention 11), one of the two hard boards is preferably a display module or a part thereof, and the other of the two hard boards is preferably on a surface of the adhesive layer side, Frame-shaped uneven protective plate (Invention 14).

In the above inventions (Inventions 9 to 14), the total light transmittance of the adhesive layer is preferably 80% or more.

Fourth, the present invention provides a pressure-sensitive adhesive sheet having a weight average molecular weight of 200,000 to 900,000 as a monomer unit constituting a polymer, containing 5 to 20% by mass of a monomer having a carboxyl group, or 15% by weight. (%) To 30% by mass of a (meth) acrylate copolymer (A) of a monomer having a hydroxyl group, an active energy ray curable component (B), and a bridging agent (C), and the active energy ray curable component (B) The content of 5% by weight is 50 μm to 400 μm, based on 100 parts by mass of the (meth) acrylate copolymer (A).剂 层。 The agent layer.

In the above invention, the adhesive layer obtained by thermally bridging an adhesive composition containing a (meth) acrylate copolymer having a small weight average molecular weight and containing a certain amount of hydroxyl or carboxyl groups, the unevenness followability, and Excellent moist-heat whitening resistance and excellent durability. In addition, the adhesive composition contains a large amount of active energy ray-curable components, and the adhesive layer is cured by irradiation with active energy rays. The thus cured adhesive layer is excellent in durability and blister resistance.

In the above invention, the content of the bridging agent (C) in the adhesive composition is preferably 0.01 to 5 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A).

The adhesive layer of the active energy ray-curable adhesive sheet according to the present invention has excellent unevenness followability, and after active energy ray irradiation, it also has excellent moist heat whitening resistance, durability, and blister resistance. In a laminated body obtained by using such an active energy ray-curable adhesive sheet, even if there are irregularities on the adhesive layer side, the adhesive layer will follow the irregularities, so that no floating or bubbles are generated near the irregularities. Wait. Moreover, in the said laminated body, the adhesive layer after active energy ray irradiation is also excellent in moist-heat whitening resistance, durability, and blister resistance.

1‧‧‧Active energy ray curable adhesive sheet

11‧‧‧Adhesive layer

12a, 12b ‧‧‧ peeling sheet

2‧‧‧ laminated body

21‧‧‧The first hard board

22‧‧‧The second hard board

3‧‧‧print layer

FIG. 1 is a cross-sectional view of an active energy ray-curable adhesive sheet according to an embodiment of the present invention.

FIG. 2 is a sectional view of a laminated body according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described.

[Active energy ray-curable adhesive sheet]

As shown in FIG. 1, the active energy ray-curable adhesive sheet 1 described in this embodiment (in this specification, it may be simply referred to as an “adhesive sheet”). The two release sheets 12 a and 12 b and the The two release sheets 12a and 12b are configured such that the release surfaces of the two release sheets 12a and 12b are in contact with each other and sandwich the adhesive layer 11 of the two release sheets 12a and 12b. The release surface of the release sheet in the present specification refers to a surface having releasability in the release sheet, and includes both a surface subjected to a release treatment and a surface that exhibits releasability even without a release treatment.

Adhesive layer

The adhesive layer 11 contains a monomer unit constituting a polymer having a weight average molecular weight of 200,000 to 900,000, and contains 5% to 20% by mass of a monomer having a carboxyl group (carboxyl-containing monomer) or 15 to 30% by mass (meth) acrylate copolymer (A) of a monomer (hydroxyl-containing monomer) having a hydroxyl group, an active energy ray-curable component (B), and a bridging agent (C) Composition (hereinafter may be referred to as "adhesive composition P".) An active energy ray-curable adhesive layer composed of a thermal bridge. In addition, in this specification, (meth) acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms.

The adhesive layer 11 in the adhesive sheet 1 is constituted by thermally bridging the adhesive composition P. Specifically, the (meth) acrylate copolymer (A) passes through the bridging agent (C) to become a bridging agent. status. On the other hand, the active energy ray-curable component (B) is not yet cured, and exists in the adhesive layer 11 in a state of being mixed with the adhesive composition P. The active energy ray-curable component (B) is polymerized and cured when the adhesive sheet 1 is used (when the adherend is bonded) when the active energy ray is irradiated to the adhesive layer 11.

(1) (meth) acrylate copolymer (A)

The (meth) acrylate copolymer (A) is an adhesion main agent in the adhesive composition P. The (meth) acrylate copolymer (A), as a monomer unit constituting the polymer, contains 5 to 20% by mass of a carboxyl group-containing monomer, or 15 to 30% by mass of a hydroxyl group-containing monomer. . If the content of the carboxyl group-containing monomer or the hydroxyl group-containing monomer is within the above range, the bridging structure formed by the (meth) acrylate copolymer (A) and the bridging agent (C) becomes good, and the adhesive layer 11 is excellent. Of durability. The adhesive layer 11 obtained from the adhesive composition P containing a (meth) acrylate copolymer (A) having a carboxyl group-containing monomer or a hydroxyl group-containing monomer in the above-mentioned range is After the adhesive layer 11 is cured, under high-temperature and high-humidity conditions (for example, under conditions of 85 ° C. and 85% RH for 240 hours), whitening upon returning to normal temperature and humidity is suppressed, that is, it has excellent moist heat and whitening resistance . When the (meth) acrylate copolymer (A) contains a carboxyl group-containing monomer or a hydroxyl group-containing monomer in the above-mentioned amount as a monomer unit, a certain amount of carboxyl group or hydroxyl group remains in the obtained adhesive. The carboxyl group and the hydroxyl group are hydrophilic functional groups. If such hydrophilic functional groups are present in the adhesive in a certain amount, it is presumed that even if the adhesive is placed under high temperature and high humidity conditions, it is immersed in the adhesive under the high temperature and high humidity conditions. When the moisture of the adhesive is restored to normal temperature and humidity, it is easy to detach from the adhesive. As a result, whitening of the adhesive is suppressed.

In the (meth) acrylate copolymer (A), as the monomer unit, if the content of the carboxyl group-containing monomer is less than 5 mass%, or the content of the hydroxyl group-containing monomer is less than 15 mass%, the adhesive layer 11 In particular, moist heat and whitening resistance will decrease. On the other hand, when the content of the carboxyl group-containing monomer exceeds 20% by mass, or the content of the hydroxyl group-containing monomer exceeds 30% by mass, the workability of the adhesive composition P is deteriorated.

From the viewpoints described above, the (meth) acrylate copolymer (A), as a monomer unit constituting the polymer, preferably contains 7 to 15% by mass, particularly 8 to 12% by mass. A carboxyl monomer, or a hydroxyl-containing monomer containing 17% to 28% by mass, particularly 20% to 25% by mass.

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Among these, (meth) acrylic acid is preferred, and particularly preferred is (meth) acrylic acid from the viewpoint of the reactivity of the carboxyl group in the obtained (meth) acrylate polymer (A) with the bridging agent (B) and the copolymerizability with other monomers. For acrylic. These may be used alone or in combination of two or more.

Examples of the hydroxyl-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and (meth) 2-hydroxybutyl (meth) acrylate, hydroxyalkyl (meth) acrylate, and the like, such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Among these, (meth) acrylic acid 2- (meth) acrylic acid ester polymer (A) is preferably a (meth) acrylic acid 2- from the viewpoint of the reactivity of the hydroxyl group with the bridging agent (B) and the copolymerizability with other monomers. Hydroxyethyl ester. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A), as a monomer unit constituting the polymer, is preferably an (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms containing an alkyl group, and particularly preferably used as a main component. Ingredients. Thus, the obtained adhesive can exhibit excellent adhesiveness.

Examples of the alkyl (meth) acrylate having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. Ester, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isomethacrylate Octyl ester, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, (methyl) ) Stearyl acrylate and the like. Among these, from the viewpoint of further improving the adhesion, (meth) acrylates having 1 to 8 carbon atoms in the alkyl group are preferred, and methyl (meth) acrylate and n-butyl (meth) acrylate are particularly preferred. Esters and 2-ethylhexyl (meth) acrylate. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A), as a monomer unit constituting the polymer, is preferably a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms having an alkyl group of 50% by mass or more, and particularly preferably It is 60% by mass or more, and more preferably 70% by mass or more. The upper limit of the content of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group is preferably the remainder other than the carboxyl group-containing monomer and the hydroxyl group-containing monomer.

The (meth) acrylate copolymer (A) may contain other monomers as a monomer unit constituting the polymer, if necessary. As another monomer, it is preferable not to contain the monomer which has a reactive functional group, even if it does not inhibit the reaction of a carboxyl group-containing monomer or a hydroxyl group-containing monomer. Examples of such monomers include alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; (meth) (Meth) acrylates having an aliphatic ring, such as cyclohexyl acrylate; non-bridged acrylamide, such as acrylamide, methacrylamide; N, N-dimethylaminoethyl (meth) acrylate (Meth) acrylic acid esters having non-bridged tertiary amino groups such as N, N-dimethylaminopropyl (meth) acrylic acid; vinyl acetate, styrene, and the like. These may be used alone or in combination of two or more.

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

The weight average molecular weight of the (meth) acrylate copolymer (A) is 200,000 to 900,000, and preferably 250,000 to 700,000. In addition, the weight average molecular weight in this specification is a polystyrene conversion value measured by the gel permeation chromatography (GPC) method.

The weight average molecular weight of the main component (meth) acrylate copolymer (A) of the adhesive composition P is small as described above, and the adhesive layer 11 obtained by thermally bridging the adhesive composition P is 11 , Has excellent uneven followability. When the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) exceeds 900,000, the unevenness followability is reduced. On the other hand, if the weight average molecular weight of the (meth) acrylate copolymer (A) is less than 200,000, the durability of the adhesive layer 11 after active energy ray irradiation is reduced. From the above viewpoint, from the viewpoint of unevenness followability and durability, the weight average molecular weight of the (meth) acrylate copolymer (A) is particularly preferably 300,000 to 500,000. From the viewpoint of blister resistance, The weight average molecular weight of the (meth) acrylate copolymer (A) is particularly preferably 500,000 to 700,000.

Moreover, in the adhesive composition P, a (meth) acrylate copolymer (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

(2) Active energy ray curable component (B)

The adhesive layer P formed by containing the active energy ray-curable component (B) is an active energy ray-curable adhesive layer. The adhesive layer 11 is excellent in unevenness followability and durability by containing an active energy ray-curable component (B).

The active energy ray-curable component (B) is not particularly limited as long as it is a component that is cured by irradiation with active energy rays without impeding the effects of the present invention, and may be any of monomers, oligomers, and polymers. One kind or a mixture of them. Among these, a polyfunctional acrylate-based monomer having a molecular weight of less than 1,000, which has excellent compatibility with the (meth) acrylate copolymer (A) and the like, can be cited.

Examples of the polyfunctional acrylate monomer having a molecular weight of less than 1,000 include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and neopentyl Alcohol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) Acrylate, dicyclopentyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified phosphate di (meth) acrylate, di ( 2-functional types such as propylene ethoxyethyl) isocyanate, allyl cyclohexyl di (meth) acrylate; trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate , Propionic acid-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (propyleneoxyethyl) ) Isocyanate, ε-caprolactone modified tri- (2- (meth) acryloxyethyl) isocyanate, etc .; trifunctional type; diglycerol tetra (meth) acrylate, pentaerythritol 4-functional types such as tetra (meth) acrylate; 5-functional types such as propionic acid-modified dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa 6-functional type such as (meth) acrylate. These may be used alone or in combination of two or more.

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

Here, the polyester acrylate-based oligomer can be obtained by, for example, using (meth) acrylic acid and polycondensing a polycarboxylic acid and a polyhydric alcohol to obtain a hydroxyl group and an ester of a polyester oligomer having hydroxyl groups at both ends. Alternatively, it can be obtained by esterifying a hydroxy group terminal of an oligomer obtained by adding an alkylene oxide to a polycarboxylic acid with (meth) acrylic acid. The epoxy acrylate-based oligomer can be obtained, for example, by reacting and esterifying (meth) acrylic acid on an ethylene oxide ring of a bisphenol-type epoxy resin and a novolac-type epoxy resin. A carboxy-modified epoxy acrylate oligomer obtained by partially modifying the epoxy acrylate-based oligomer with a dibasic carboxylic anhydride may also be used. The urethane acrylate oligomer can be obtained, for example, by esterifying a urethane oligomer obtained by reacting a polyether polyol and a polyester polyol with a polyisocyanate using (meth) acrylic acid. The polyol acrylate oligomer can be obtained by esterifying a hydroxyl group of a polyether polyol with (meth) acrylic acid.

The weight average molecular weight of the acrylate oligomer is preferably 50,000 or less, particularly preferably 500 to 50,000, and still more preferably 3,000 to 40,000. These acrylate oligomers may be used singly or in combination of two or more kinds.

In addition, as the active energy ray-curable component (B), an adduct acrylate-based polymer obtained by introducing a group having a (meth) acrylfluorenyl group into a side chain may be used. Such an adduct acrylate-based polymer can have a copolymer with a (meth) acrylfluorene group and a bridging functional group by using a copolymer of (meth) acrylate and a monomer having a bridging functional group in the molecule. A compound of a reactive group is obtained by reacting with a part of the bridging functional group of the copolymer.

The (meth) acrylate is preferably an alkyl (meth) acrylate containing 1 to 20 carbon atoms in the alkyl group, and examples thereof include methyl (meth) acrylate and ethyl (meth) acrylate Ester, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) ) 2-ethylhexyl acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, ( Cetyl (meth) acrylate, stearyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

The monomer having a bridging functional group in the molecule preferably contains, as a functional group, at least one selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an amido group. Examples of the monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and (meth) acrylic acid 2 -Hydroxybutyl (meth) acrylate, such as hydroxybutyl ester, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate; N-hydroxymethacrylamide, etc. Allylamines; monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, (meth) acrylic acid Monoalkylaminoalkyl (meth) acrylates such as monoethylaminopropyl esters; ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid Wait. These monomers may be used alone or in combination of two or more.

As the compound having a group that reacts with a (meth) acrylfluorenyl group and a bridging functional group, for example, 2-methacrylfluorenyloxyethyl isocyanate and methacrylic acid 2- (0- [1 '-Methylpropaneamino] carboxyamino) ethyl, 2-[(3,5-dimethylpyridine) carbonylamino] ethyl methacrylate, 1,1- (bispropenyloxymethyl) Ethyl isocyanate, 2-propenyloxyethyl isocyanate, 2-propenyloxyethyl succinate, 2-propenyloxyethylhexahydrophthalimide, imine, ω-carboxy-polycaprolactone mono Acrylate, phthalic acid monohydroxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and the like. These compounds may be used alone or in combination of two or more.

The weight average molecular weight of the adduct acrylate polymer is preferably about 50,000 to 900,000, and particularly preferably about 100,000 to 300,000.

The active energy ray-curable component (B) may be selected from one of the above-mentioned polyfunctional acrylate monomers, acrylate oligomers, and adduct acrylate polymers, or two or more of them may be used. They can be used in combination, and can also be used in combination with other active energy ray-curable components.

The content of the active energy ray-curable component (B) in the adhesive composition P needs to be 10 to 50 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A), and is preferably 15 to 45 parts by mass, and particularly preferably 25 to 40 parts by mass. When the content of the active energy ray-curable component (B) is 10 parts by mass or more, the cohesive force of the adhesive layer 11 after the active energy ray irradiation is increased, and even if the plastic plate is degassed in a high-temperature environment, bubbles can be suppressed Or the occurrence of floating and peeling is excellent in blister resistance. That is, if the content of the active energy ray-curable component (B) is less than 10 parts by mass, excellent blisters resistance of the adhesive layer 11 after active energy ray irradiation cannot be obtained. On the other hand, when the content of the active energy ray-curable component (B) exceeds 50 parts by mass, the adhesive force of the adhesive layer 11 before the active energy ray irradiation becomes too high, and the release sheet is peeled from the adhesive layer 11 It is difficult to peel off 12a and 12b smoothly. When peeling off the peeling sheets 12a and 12b, the adhesive layer 11 may be damaged. In addition, since the adhesive layer 11 after irradiation with active energy rays has an adhesive force (to a glass substrate) of 10 N / 25 mm or more, it is possible to firmly maintain the bonding state between the hard plates.

(3) bridging agent (C)

The adhesive composition P contains a bridging agent (C) and bridges the (meth) acrylate copolymer (A) to form a three-dimensional network structure, thereby improving the cohesive force of the obtained adhesive. In addition, after the active energy ray is irradiated, the adhesive may be given durability.

The bridging agent (C) may be a bridging agent that is reactive with a reactive functional group (carboxyl group or hydroxyl group) of the (meth) acrylate copolymer (A), and examples thereof include isocyanate bridging agents. , Epoxy bridging agent, amine bridging agent, melamine bridging agent, aziridine bridging agent, hydrazine bridging agent, aldehyde bridging agent, oxaline bridging agent, metal alkoxide bridging agent, metal chelate Compound bridging agent, metal salt bridging agent, ammonium salt bridging agent, etc. The bridging agent (C) may be used singly or in combination of two or more kinds.

When the (meth) acrylate copolymer (A) contains a carboxyl group-containing monomer, it is preferable to use at least one selected from the group consisting of an epoxy-based bridging agent and an isocyanate-based bridging agent having excellent reactivity with a carboxyl group (C ), Particularly preferably an epoxy-based bridging agent. When the (meth) acrylate copolymer (A) contains a hydroxyl-containing monomer, it is preferable to use an isocyanate-based cross-linking agent having excellent reactivity with a hydroxyl group.

Examples of the epoxy-based bridging agent include 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, and N, N, N ', N'-tetraglycidyl di-bis Toluenediamine, ethylene glycol diglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, diglycidylamine, and the like.

The isocyanate-based bridging agent is a bridging agent containing at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as methylenephenyl diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; isophorone Alicyclic polyisocyanates, such as diisocyanates, hydrogenated diphenylmethane diisocyanates, etc .; and these bisuretons, isocyanates; further examples include ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor Adducts of sesame oil and the like as reactants with low-molecular active hydrogen compounds.

The content of the bridging agent (C) in the adhesive composition P is preferably 0.01 to 5 parts by mass, and particularly preferably 0.05 to parts by mass, with respect to 100 parts by mass of the (meth) acrylate copolymer (A). 1 part by mass. When the content of the cross-linking agent (C) is 0.01 parts by mass or more, the adhesive after irradiation with active energy rays can provide an effect of improving durability. When the content of the bridging agent (C) exceeds 5 parts by mass, the degree of bridging is excessive, and the unevenness followability of the obtained adhesive may be reduced. In addition, a large number of carboxyl groups or hydroxyl groups of the (meth) acrylate copolymer (A) react with the bridging agent (C), and the amount of carboxyl groups or hydroxyl groups remaining in the adhesive decreases, and the moisture-heat whitening resistance may be reduced. From the above point of view, the content of the bridging agent (C) is preferably 0.05 parts by mass to 0.4 parts by mass from the viewpoint of optimizing durability, and the bridging agent (C) is preferred from the viewpoint of optimizing blister resistance. The content of is preferably 0.3 to 1 part by mass.

(4) Photopolymerization initiator (D)

As an active energy ray irradiated to the adhesive layer 11, when using an ultraviolet-ray, it is more preferable that the adhesive composition P contains a photoinitiator (D). By containing the photopolymerization initiator (D) as described above, the active energy ray-curable component (B) can be effectively cured, and the polymerization curing time and the amount of irradiation of the active energy ray can be reduced.

Examples of such a photopolymerization initiator (D) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, Benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylbenzene Ethyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] 2-morpholin-propane-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) one, benzophenone, p-phenylbenzophenone , 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2 -Methylxanthone, 2-ethylxanthone, 2-chloroxanthone, 2,4-dimethylxanthone, 2,4-diethylxanthone, benzyldimethylketal Ketone, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) benzene] acetone], 2 , 4,6-trimethylbenzylidene-diphenyl-phosphine oxide and the like. These may be used alone or in combination of two or more.

The photopolymerization initiator (D) is preferably used in an amount ranging from 2 parts by mass to 15 parts by mass with respect to 100 parts by mass of the active energy ray-curable component (B), and particularly in an amount ranging from 4 parts by mass to 12 parts by mass.

(5) Various additives

The adhesive composition P may be added with various additives commonly used in acrylic adhesives, such as a silane coupling agent, an antistatic agent, an adhesion preventing agent, an oxidation preventing agent, an ultraviolet absorber, and a light, as needed. Stabilizer, flame retardant, filler, refractive index adjuster, etc.

Particularly from the viewpoint of improving durability, it is preferable to add a silane coupling agent as an additive to the adhesive composition P. The silane coupling agent is an organosilicon compound having at least one alkoxysilyl group in the molecule, and preferably has good compatibility with the (meth) acrylate copolymer (A). When the adhesive sheet 1 is used for optical applications, a silane coupling agent having light transmittance is preferable.

Examples of the silane coupling agent include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, and the like. -Silicon compounds having an epoxy structure such as glycidoxytrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3 -Mercapto-containing silicon compounds such as mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl)- Amino-containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-isocyanate propyltriethoxysilane, or at least one of these with methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. Condensates of alkyl silicon compounds and the like. These may be used alone or in combination of two or more.

The addition amount of the silane coupling agent is preferably 0.01 to 1.0 parts by mass, and particularly preferably 0.05 to 0.5 parts by mass, with respect to 100 parts by mass of the (meth) acrylate copolymer (A).

(6) Production of adhesive composition

The adhesive composition P can be produced by (meth) acrylate copolymer (A), and the obtained (meth) acrylate copolymer (A), an active energy ray-curable component (B), and a bridging agent ( C) It mixes and manufactures by adding a photoinitiator (D) and / or an additive as needed.

The (meth) acrylate copolymer (A) can be produced by polymerizing a mixture of monomers constituting a polymer by a general radical polymerization method. The polymerization of the (meth) acrylate copolymer (A) can be performed by a solution polymerization method or the like using a polymerization initiator as necessary. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more of them may be used in combination.

Examples of the polymerization initiator include an azo compound, an organic peroxide, and the like, and two or more of them may be used simultaneously. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), and 1,1'-azobis (cyclohexane 1). -Nitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), Dimethyl 2,2'-azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxy Methylpropionitrile), 2,2'-azobis [2- (2-imidoline-2-yl) propane], and the like.

Examples of the organic peroxide include benzamidine peroxide, tert-butyl peroxybenzoate, cumene hydrogen peroxide, diisopropylperoxydicarbonate, and di-n-propylperoxy. Dicarbonate, bis (2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxynecaprylate, tert-butyl peroxypivalate, (3,5,5-trimethyl Hexamethylene) peroxide, dipropylhydrazone peroxide, diethylhydrazone peroxide, and the like.

Moreover, in the said polymerization process, the weight average molecular weight of the obtained polymer can be adjusted by mix | blending a chain shifting agent, such as 2-mercaptoethanol.

After the (meth) acrylate copolymer (A) is obtained, to the solution of the (meth) acrylate copolymer (A), an active energy ray-curable component (B), a bridging agent (C) are added, and if necessary, added The photopolymerization initiator (D) and additives are sufficiently mixed to obtain an adhesive composition P.

(7) Formation of adhesive layer

The adhesive layer 11 is formed by thermally bridging the adhesive composition P. That is, the bridging of the adhesive composition P is performed by heat processing. This heat treatment can also be used as a drying treatment after the adhesive composition P is applied.

The heating temperature of the heat treatment is preferably 50 ° C to 150 ° C, and particularly preferably 70 ° C to 120 ° C. The heating time is preferably 10 seconds to 10 minutes, and particularly preferably 50 seconds to 2 minutes. After the heat treatment, if necessary, it can be kept at a normal temperature (for example, 23 ° C., 50% RH) for a maturation period of about 1 to 2 weeks. When the maturation period is required, the maturation period is passed; when the maturation period is not required, the adhesive layer is formed after the heat treatment is completed.

Through the heat treatment (and maturation) of the bridging agent (C), the (meth) acrylate copolymer (A) is well bridged.

The thickness (value measured based on JIS K7130) of the formed adhesive layer 11 is 50 μm to 400 μm, preferably 70 μm to 300 μm, and particularly preferably 90 μm to 250 μm. The adhesive layer 11 may be formed of a single layer or a plurality of layers.

When the thickness of the adhesive layer 11 is less than 50 μm, sufficient unevenness followability cannot be obtained, and when the thickness of the adhesive layer 11 exceeds 400 μm, processability is reduced.

2. Release sheet

Examples of the release sheets 12a and 12b include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, and a polymer film. Terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene- (methyl Based) acrylic copolymer film, ethylene- (meth) acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. These bridge films can also be used. Furthermore, these laminated films may be used.

It is preferable that a peeling process is performed on the peeling surface (especially the surface which contacts the adhesive layer 11) of the said peeling sheet 12a, 12b. Examples of the release agent used in the peeling treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. Moreover, among the peeling sheets 12a and 12b, it is preferable that the peeling sheet of one side is a heavy peeling type peeling sheet with a large peeling force, and the peeling sheet of the other side is a light peeling type peeling sheet with a small peeling force.

The thickness of the release sheets 12a and 12b is not particularly limited, but is usually about 20 μm to 150 μm.

3. Manufacturing of adhesive sheet

As an example of manufacturing the adhesive sheet 1, the coating liquid of the adhesive composition P is coated and heat-treated on the release surface of one release sheet 12a (or 12b) to thermally bridge the adhesive composition P. After the coating layer is formed, the release surface of the other release sheet 12b (or 12a) is polymerized on the coating layer. When the ripening period is required, the ripening period is retained; when the ripening period is not required, the coating layer directly becomes the adhesive layer 11. Thereby, the above-mentioned adhesive sheet 1 is obtained. In addition, at this stage, active energy rays are not irradiated.

As another example of manufacturing the adhesive sheet 1, the coating liquid of the adhesive composition P is coated and heated on the release surface of one release sheet 12a, and the adhesive composition P is thermally bridged to form a coating layer. Thus, a release sheet 12a with a coating layer was obtained. In addition, on the release surface of the other release sheet 12b, the coating solution of the adhesive composition P was coated and heated, and the adhesive composition P was thermally bridged to form a coating layer to obtain a coating layer with a coating layer. The release sheet 12b. Then, the release sheet 12a with a coating layer and the release sheet 12b with a coating layer are bonded together, and the two coating layers are brought into contact with each other. When the ripening period is required, the ripening period is retained; when the ripening period is not required, the above-mentioned laminated coating layer directly becomes the adhesive layer 11. Thereby, the above-mentioned adhesive sheet 1 is obtained. According to this manufacturing example, even when the adhesive layer 11 is thick, it can be stably manufactured.

As a method of applying the coating liquid of the adhesive composition P, for example, a bar coating method, a blade coating method, a roll coating method, a plate coating method, a mold coating method, a gravure coating method, or the like can be used.

4. Physical properties

The ratio of the storage modulus at 23 ° C after the adhesive layer 11 is irradiated with the active energy ray, relative to the storage modulus at 23 ° C before the adhesive layer 11 is irradiated with the active energy ray (active energy ray irradiation After storage modulus / storage modulus before active energy ray irradiation), it is preferably 1.1 to 10, and particularly preferably 1.2 to 7. The storage modulus in this specification is a value measured by a torsional shear method at a measurement frequency of 1 Hz based on JIS K7244-6.

As described above, after the active energy ray is irradiated (after curing), the storage modulus of the adhesive layer 11 at 23 ° C. increases, and the cured adhesive layer 11 is excellent in durability and unevenness followability. In addition, from the viewpoint described above, from the viewpoint of blister resistance, the ratio of the storage modulus is particularly preferably 3 to 7.

In addition, the ratio of the storage modulus at 85 ° C. after the active energy ray is irradiated to the adhesive layer 11 is compared to the storage modulus at 85 ° C. (active energy) The storage modulus after the linear irradiation / the storage modulus before the active energy ray irradiation) is preferably 1.1 to 10, and particularly preferably 1.3 to 7. In addition, from the viewpoint described above, from the viewpoint of blister resistance, the ratio of the storage modulus is particularly preferably 3 to 7.

As described above, after the active energy ray is irradiated (after curing), the storage modulus of the adhesive layer 11 at 85 ° C. is increased, and the cured adhesive layer 11 is excellent in durability even at a high temperature.

If the ratio of the above-mentioned storage modulus at 23 ° C or 85 ° C is less than 1.1, the effect of improving durability as described above may not be obtained. On the other hand, if the ratio of the storage modulus at 23 ° C. or 80 ° C. exceeds 10, the adhesive force of the cured adhesive layer 11 is reduced, and sufficient durability may not be obtained.

The storage modulus of the adhesive layer 11 before active energy ray irradiation at 23 ° C. is preferably 0.01 MPa to 0.2 MPa, particularly preferably 0.04 MPa to 0.15 MPa, and still more preferably 0.07 MPa to 0.1 MPa. In addition, the storage modulus of the adhesive layer 11 before activation energy ray irradiation at 85 ° C. is preferably 0.01 MPa to 0.1 MPa, particularly preferably 0.01 MPa to 0.06 MPa, and even more preferably 0.02 MPa to 0.04 MPa. The adhesive layer 11 before the active energy ray irradiation has the above-mentioned storage modulus, and thus has excellent unevenness followability.

The storage modulus of the adhesive layer 11 after the active energy ray irradiation at 23 ° C. is preferably 0.02 MPa to 2 MPa, particularly preferably 0.05 MPa to 1 MPa, and still more preferably 0.1 MPa to 0.6 MPa. In addition, the storage modulus of the adhesive layer 11 after irradiation with active energy rays at 85 ° C. is preferably 0.02 MPa to 0.5 MPa, particularly preferably 0.02 MPa to 0.2 MPa, and still more preferably 0.03 MPa to 0.1 MPa. The adhesive layer 11 after active energy ray irradiation is excellent in durability and blister resistance by having the storage modulus as described above.

The above adhesive sheet 1 has excellent unevenness followability because of the adhesive layer 11 before the active energy ray irradiation. Therefore, even when the adherend has unevenness, it is difficult for the unevenness and the adhesive layer 11 to appear. Voids or air bubbles are generated, and the adhesive layer 11 can fill the unevenness. In addition, the adhesive layer 11 is cured by irradiation with active energy rays, and is excellent in moist heat whitening resistance, durability, and blister resistance.

As described later, the adhesive layer 11 of the adhesive sheet 1 in this embodiment is preferably used for bonding two hard boards to each other.

[Laminated body]

As shown in FIG. 2, the laminated body 2 according to this embodiment is composed of a first hard plate 21, a second hard plate 22, and an adhesive sandwiched between the first hard plate 21 and the second hard plate 22. The adhesive layer 11 is formed. In the laminated body 2 according to the present embodiment, the first hard plate 21 has unevenness on the surface on the side of the adhesive layer 11, and specifically has unevenness due to the presence or absence of the print layer 3.

The first hard plate 21 and the second hard plate 22 are not particularly limited as long as the adhesive layer 11 can be adhered. The first rigid plate 21 and the second rigid plate 22 may be the same material or different materials.

As the first rigid plate 21 and the second rigid plate 22, for example, in addition to glass plates, plastic plates, metal plates, and semiconductor plates, these laminated bodies, or plate-shaped rigid plates such as display modules and solar cell modules can also be cited. Products, etc. Since the adhesive layer 11 in this embodiment is excellent in blister resistance, at least one of the first hard plate 21 and the second hard plate 22 preferably includes a plastic plate.

The glass plate is not particularly limited, and examples thereof include chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, barium strontium glass, aluminosilicate glass, lead glass, borosilicate glass, and barium borosilicate. Acid glass and so on. The thickness of the glass plate is not particularly limited, but is usually 0.1 mm to 5 mm, and preferably 0.2 mm to 2 mm.

The plastic plate is not particularly limited, and examples thereof include an acrylic plate and a polycarbonate plate. The thickness of the plastic plate is not particularly limited, but is usually 0.2 mm to 5 mm, and preferably 0.4 mm to 3 mm.

In addition, various functional layers (transparent conductive film, metal layer, silicon dioxide layer, hard coating layer, anti-glare layer, etc.) may be formed on one or both sides of the glass plate and the plastic plate, and metal wiring may also be formed. There may be laminated optical components.

Examples of the optical member include a polarizing plate (polarizing film), a polarizer, a retardation plate (a retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, a diffusion film, and a hard coating. Layer film, transflective film, etc.

Examples of the display module include a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroplating cold light (organic EL) module, and electronic paper. In addition, in these display modules, the above-mentioned glass plate, plastic plate, optical member and the like are usually laminated. For example, a polarizing plate is laminated in the LCD module, and the polarizing plate forms a side surface of the LCD module.

In the laminated body 2 according to the present embodiment, it is preferable that at least one surface of the first hard plate 21 and the second hard plate 22 has a polarizing plate. In the laminated body 2 according to the present embodiment, the second rigid plate 22 is preferably a display module or a part thereof (for example, an optical member such as a polarizing plate), and the first rigid plate 21 is a protective plate made of a plastic plate or the like. At this time, the print layer 3 is generally formed in a frame shape on the adhesive layer 11 side of the first hard board 21.

The material constituting the printed layer 3 is not particularly limited, and a known material for printing is used. The thickness of the printed layer 3, that is, the height of the unevenness, is preferably 3 μm to 45 μm, particularly preferably 5 μm to 35 μm, further preferably 7 μm to 25 μm, and even more preferably 7 μm to 15 μm.

The thickness (height of the unevenness) of the printed layer 3 is preferably 3% to 30% of the thickness of the adhesive layer 11, particularly preferably 3.2% to 20%, and still more preferably 3.5% to 15%. Thereby, the adhesive layer 11 can reliably follow the unevenness due to the printed layer 3, and no floating, bubbles, etc. occur near the unevenness.

In the present embodiment, the adhesive layer 11 of the multilayer body 2 is cured by irradiating the adhesive layer 11 in the adhesive sheet 1 with active energy rays. The active energy ray here means that there is an energy quantum in an electromagnetic wave or a charged particle beam, and specific examples include ultraviolet rays and electron beams. Among the active energy rays, ultraviolet rays that are easy to handle are also particularly preferred.

The irradiation of ultraviolet rays can be performed by a high-pressure mercury lamp, a Fusion H lamp, a xenon lamp, or the like, and the irradiation amount of ultraviolet rays is preferably about 50 mW / cm ² to 1,000 mW / cm ² . Further, the light amount is preferably ^{50mJ / cm 2 ~ 10000mJ / cm} 2, particularly preferably ^{80mJ / cm 2 ~ 5000mJ / cm} 2, more preferably ^{200mJ / cm 2 ~ 2000mJ / cm} 2. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 krad to 1,000 krad.

When the active energy ray is irradiated to the adhesive layer 11 of the adhesive sheet 1, the active energy ray-curable component (B) is polymerized and cured. The adhesive layer 11 cured by irradiation with active energy rays is excellent in durability, moisture-heat whitening resistance, and blister resistance.

To manufacture the laminated body 2 described above, as an example, first, a peeling sheet 12a (or 12b) of the adhesive sheet 1 is peeled off, and the adhesive layer 11 and the first hard plate 21 (or the second hard sheet) exposed by the adhesive sheet 1 are peeled off. Board 22) fits. Next, the other peeling sheet 12b (or 12a) is peeled from the adhesive layer 11 of the adhesive sheet 1, and the adhesive layer 11 and the second hard board 22 (or the first hard sheet) exposed by the adhesive sheet 1 are peeled off. Plate 21) fits.

When the adhesive layer 11 and the first hard board 21 are bonded in the above steps, the adhesive layer 11 has excellent unevenness followability, and it is difficult to generate a gap between the unevenness of the print layer 3 and the adhesive layer 11. The adhesive layer 11 can fill the unevenness.

Then, from either side of the first hard plate 21 or the second hard plate 22, the adhesive layer 11 is irradiated with active energy rays to cure the adhesive layer 11. At this time, the hard board irradiating the active energy ray side needs to have active energy ray permeability.

In the laminated body 2 described above, since the adhesive layer 11 before the active energy ray irradiation has excellent unevenness followability, voids or bubbles are hardly generated between the unevenness of the printed layer 3 and the adhesive layer 11. In addition, after the adhesive layer 11 cured by irradiation with active energy rays is subjected to high-temperature and high-humidity conditions, whitening at the time of returning to normal temperature is suppressed, and moisture-heat whitening resistance is excellent. In addition, the adhesive layer 11 irradiated with active energy rays can prevent the occurrence of bubbles and the like near the unevenness even when a high-temperature and high-humidity condition is implemented, and has excellent durability. In addition, at least one of the first hard plate 21 and the second hard plate 22 may include a plastic plate. Even if the plastic plate is degassed under high temperature conditions, the adhesive layer 11 irradiated with active energy rays is resistant to blisters. It is also excellent in properties, and therefore, occurrence of bubbles, floating, and peeling is suppressed.

The excellent wet heat whitening resistance of the adhesive layer 11 cured by irradiating active energy rays can be evaluated as follows. For example, the two sides of the adhesive layer 11 are sandwiched between two pieces of alkali-free glass having a thickness of 1.1 mm, and the alkali-free glass is irradiated with the above-mentioned illuminance and active energy rays on at least one side to obtain a laminated body. This laminated body was stored under the conditions (humid heat conditions) of 85 ° C. and 85% RH for 240 hours, and then taken out at 23 ° C. and 50% RH at normal temperature and normal humidity. At this time, it was confirmed that the degree of whitening of the adhesive layer 11 was small.

The degree of the whitening can be quantitatively evaluated by a haze value. Specifically, a value obtained by subtracting the haze value (%) before the moist heat condition (after the moist heat condition) from the haze value (%) of the laminate after the moist heat condition (the value measured based on JIS K7136: 2000) is the same as the value (after the moist heat condition) The haze value rises). The increase in the haze value after moist heat conditions is preferably less than 5.0 points, and particularly preferably less than 1.0 points. Moreover, in the said evaluation, as said alkali-free glass, it is preferable to use a haze value of almost 0%. In addition, the haze value of the adhesive layer after the wet heat condition is preferably 1.0% or less, particularly preferably 0.9% or less, and still more preferably 0.8% or less.

In addition, the total light transmittance (value measured based on JIS K7361-1: 1997) of the adhesive layer 11 is preferably 80% or more, particularly preferably 90% or more, and still more preferably 99% or more. If the total light transmittance is 80% or more, the transparency is high, and it is suitable for optical applications. In addition, the total light transmittance of the adhesive layer 11 is generally almost constant before and after irradiation with active energy rays.

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

For example, any one of the release sheets 12 a and 12 b of the adhesive sheet 1 may be omitted. The first hard plate 21 may have unevenness other than the printed layer 3 or may not have unevenness. Further, not only the first hard plate 21 but also the second hard plate 22 may have unevenness on the adhesive layer 11 side.

[Example]

Hereinafter, the present invention will be described in more detail through examples and the like, but the scope of the present invention is not limited by these examples and the like.

[Example 1]

1. Preparation of (meth) acrylate copolymer

60 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl methacrylate, and 20 parts by mass of 2-hydroxyethyl acrylate were copolymerized to prepare a (meth) acrylate copolymer (A). When the molecular weight of this (meth) acrylate copolymer (A) was measured by the method mentioned later, the weight average molecular weight was 600,000.

2. Preparation of adhesive composition

100 parts by mass of the (meth) acrylate copolymer (A) obtained in the step (1) (solid content conversion value; the same applies hereinafter); as the active energy ray-curable component (B), polyethylene glycol 25 parts by mass of a diacrylate (produced by Shin Nakamura Chemical Co., Ltd. under the trade name "NK Ester A-400"); as an isocyanate-based bridging agent (C), trimethylolpropane-modified methylphenyl diisocyanate (Japanese polyurethane 0.23 parts by mass of "CORONATE L" manufactured by Industrial Co., Ltd .; 0.2 mass of 3-glycidoxytrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") as a silane coupling agent 0.5 parts by mass of 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, trade name "IRUGACURE 184") was used as a photopolymerization initiator (D), and the mixture was sufficiently stirred and methyl ethyl The ketone was diluted to obtain a coating solution of an adhesive composition having a solid content concentration of 33% by mass.

The blending of this adhesive composition is shown in Table 1. The details of the abbreviations and the like described in Table 1 are as follows.

[(Meth) acrylate copolymer]

2EHA: 2-ethylhexyl acrylate

BA: n-butyl acrylate

MMA: methyl methacrylate

HEA: 2-hydroxyethyl acrylate

AA: Acrylic

[Active energy ray curable component]

A400: Polyethylene glycol diacrylate (manufactured by Shin Nakamura Chemical Co., Ltd., trade name "NK Ester A-400")

A9300-1CL: ε-caprolactone-modified tri- (2- (meth) acryloxyethyl) isocyanate (manufactured by Shin Nakamura Chemical Co., Ltd., trade name "A-9300-1CL")

[Bridge agent]

TDI: Trimethylolpropane modified methylenephenyl diisocyanate (manufactured by Japan Polyurethane Industry Co., Ltd., trade name "CORONATE L")

Epoxy: 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemical Company, trade name "TETRAD-C")

3. Manufacturing of adhesive sheet

A heavy-peeling type peeling sheet (lintec type) of the coating solution of the obtained adhesive composition was peeled on one side of a polyethylene terephthalate film with a silicone-based peeling agent A company-made, trade name "SP-PET752150") was coated with a doctor blade applicator to a thickness of 100 μm after drying, and then heated at 100 ° C. for 4 minutes to form a coating layer. Similarly, a light-peeling type release sheet (Linder) having a coating solution of the obtained adhesive composition and one side of a polyethylene terephthalate film subjected to a release treatment with a silicone-based release agent (Linde) A peeling treatment surface (trade name: "SP-PET382120", manufactured by Co., Ltd.) was applied with a doctor blade coater to a thickness of 100 μm after drying, and then a heat treatment was performed at 100 ° C. for 4 minutes to form a coating layer.

Next, the above-obtained heavy-peel-type release sheet with a coating layer and the light-peel-type release sheet with a coating layer obtained above were bonded together so that the coating layers on both sides were in contact with each other at 23 ° C. and 50% RH. It was aged for 7 days under conditions to produce an adhesive sheet composed of a heavy release type release sheet / adhesive layer (thickness: 200 μm) / light release type release sheet. The thickness of the adhesive layer is a value measured based on JIS K7130 using a constant pressure thickness gauge (manufactured by TECHLOCK, trade name "PG-02").

[Examples 2 to 4, Comparative Examples 1 to 3]

In addition to the ratio of each monomer constituting the (meth) acrylate copolymer (A), the weight average molecular weight of the (meth) acrylate copolymer (A), the type of active energy ray-curable component (B), and the combination The amount, the type and blending amount of the bridging agent (C), the blending amount of the photopolymerization initiator (D), the blending amount of the silane coupling agent, and the thickness of the adhesive layer were changed in accordance with Table 1, and were the same as in Example 1. The same operation was performed to produce an adhesive sheet.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured using a gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement conditions>

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

‧GPC column (passed in the following order): made by TOSOH

TSK guard column HXL-H

TSK gel GMHXL (× 2)

TSK gel G2000HXL

‧Determination solvent: tetrahydrofuran

‧Measuring temperature: 40 ℃

[Test Example 1] (Measurement of storage modulus)

From the pressure-sensitive adhesive sheets obtained in the examples or comparative examples, a light release-type release sheet and a heavy release-type release sheet were peeled, and the thickness of the adhesive layer was 0.6 mm, and a plurality of layers were laminated. A cylindrical body (height: 0.6 mm) having a diameter of 8 mm was punched out of the laminated body of the obtained adhesive layer, and this was used as a sample (sample before ultraviolet irradiation).

For the above-mentioned samples, the storage modulus (MPa) was measured based on JIS K7244-6 using a viscoelasticity measuring device (manufactured by Physica Co., Ltd., MCR300) according to the torsional shear method under the following conditions.

Measurement frequency: 1Hz

Measurement temperature: 23 ℃, 85 ℃

In addition, the same sample as described above was irradiated with ultraviolet rays under the following conditions by using an ultraviolet irradiation device (produced by EYE GRAPHIC, trade name "EYE GRANTAGEECS-401GX model") to cure the adhesive layer to obtain the sample. The obtained sample after ultraviolet irradiation was subjected to the same operation as that of the sample before ultraviolet irradiation, and the storage modulus (MPa) was measured.

[UV irradiation conditions]

‧Light source: high pressure mercury lamp

‧Light quantity: 1000mJ / cm2

‧Illumination: 200mW / cm2

From the above measurement results, the ratios of the storage modulus after UV irradiation to the storage modulus before UV irradiation at 23 ° C and 85 ° C (storage modulus after UV irradiation / before UV irradiation) were calculated. Storage modulus). These measurement results and calculation results are shown in Table 2.

[Test Example 2] (Processability Evaluation)

From the adhesive sheet obtained in the Example or the comparative example, a light peeling type peeling sheet was peeled, and the peeling state of the light peeling type peeling sheet at this time was evaluated as workability. Evaluation of smooth peeling of the light-peelable release sheet from the adhesive layer was good in processability ((), and evaluation of breakage of the adhesive layer when peeling the light-peelable release sheet was poor in processability (×). The results are shown in Table 2.

[Test Example 3] (Evaluation of Humidity and Whitening Resistance)

The adhesive layer of the adhesive sheet obtained in the example or the comparative example was sandwiched between two pieces of alkali-free glass having a thickness of 1.1 mm, passed over one side of the glass, and irradiated with ultraviolet rays under the ultraviolet irradiation conditions of Test Example 1. To get a laminated body. The haze value (%) of this laminated body was measured based on JIS K7136: 2000 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., trade name "NDH2000").

Then, the laminated body was stored under a humid heat condition of 85 ° C. and 85% RH for 240 hours. After that, the temperature was returned to normal temperature and humidity of 23 ° C. and 50% RH, and the haze value was measured on the layered body using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd. under the trade name “NDH2000”) based on JIS K7136: 2000 ( %). The haze value was measured within 30 minutes after the laminate was returned to normal temperature and humidity.

Based on the above results, the haze value before the moist heat condition is subtracted from the haze value after the moist heat condition, and the haze value rise (points) after the moist heat condition is calculated. Evaluation of a haze value increase of less than 1.0 point after moist heat condition is good for moist heat whitening resistance (○), and evaluation of a haze value increase of more than 1.0 point after moist heat condition is less than 5.0 point for moist heat whitening resistance (△) The evaluation that the haze value rose more than 5.0 points after the wet heat condition was poor in wet heat whitening resistance (×). The results are shown in Table 2.

[Test Example 4] (Unevenness followability and durability test)

(a) Preparation of evaluation samples

On the surface of a glass plate (manufactured by NSG PRECISION, trade name "Corning Glass, Eagle XG", 90 mm in length x 50 mm in width x 0.5 mm in thickness), a UV curable ink (manufactured by Imperial Ink Co., Ltd., trade name "POS-911 Ink ”), Screen printing was performed on a frame shape (outer shape: 90 mm in length × 50 mm in width and 5 mm in thickness) so that the coating thickness was 8 μm and 15 μm. Next, ultraviolet rays were irradiated (80 W / cm ² , ^two metal halide lamps, a lamp height of 15 cm, and a belt speed of 10 m / min to 15 m / min) to cure the printed ultraviolet curable ink to produce unevenness due to printing ( Height of unevenness: 8 μm and 15 μm).

The pressure-sensitive adhesive sheet obtained in the example or the comparative example was cut into a shape of 90 mm in length × 50 mm in width, and the light release-type release sheet was removed to expose the adhesive layer. Then, using a laminator (manufactured by Fuji Corporation, trade name "LPD3214"), the adhesive layer was completely covered with the frame-shaped printing, and the adhesive sheet was molded on a glass plate with unevenness.

After the above-mentioned plastic sealing, the heavy release type peeling sheet was peeled off, and a glass plate (product name "Corning Glass, Eagle XG", manufactured by NSG PRECISION, Inc.) was 90 mm in length, 50 mm in width, and 0.5 mm in thickness on the exposed adhesive layer. ), Plastic-sealed with the above-mentioned laminator to prepare a sample for evaluation.

(b) Evaluation of bump followability (initial)

The obtained evaluation sample was pressurized at 0.5 MPa and 50 ° C. for 30 minutes using a pressure cooker made by Kurihara Seisakusho. Then, the presence or absence of air bubbles in the adhesive layer (especially near the unevenness of the printed layer) was visually confirmed. As a result, the evaluation without bubbles was ◎, the evaluation with few bubbles was ○, and the evaluation with bubbles was ×. (Evaluation of initial unevenness compliance). The results are shown in Table 2.

(c) Evaluation of durability (concave-convex property after durability)

Next, the above-mentioned evaluation samples (1) and (2) were stored under a humid heat condition of 85 ° C. and 85% RH for 240 hours. Thereafter, the presence or absence of air bubbles in the adhesive layer (especially in the vicinity of the unevenness of the printed layer) was visually confirmed. As a result, the evaluation without bubbles was ◎, the evaluation with few bubbles was ○, and the evaluation with bubbles was ×. (Durability (concave-convex conformability after durability) evaluation). The results are shown in Table 2.

[Test Example 5] (Measurement of total light transmittance)

The adhesive layer of the adhesive sheet obtained in the Example or the comparative example was bonded to glass, and it was set as the sample for a measurement. After the background measurement was performed on glass, the measurement sample was measured for total light transmittance (%) using a haze meter (NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7361-1: 1997. . The results are shown in Table 2.

[Test Example 6] (Evaluation of blister resistance)

A 125 μm-thick polyethylene terephthalate film (ITO film) made of a transparent conductive film made of indium tin oxide (ITO) was formed on one surface by sputtering.

For the adhesive layer of the adhesive sheet obtained in the examples or comparative examples, the transparent conductive film of the ITO film and a 1 mm thick polycarbonate plate (manufactured by Mitsubishi Gas Chemical Co., Ltd. under the trade name "UPIRON‧SHEET MR58" were used. '') A sandwich was passed through the polycarbonate plate and irradiated with ultraviolet rays under the ultraviolet irradiation conditions of Test Example 1 to obtain a laminated body.

The obtained laminated body was autoclaved under conditions of 50 ° C. and 0.5 MPa for 30 minutes, and then left for 15 hours. Then, it was stored for 72 hours under the durable conditions of 85 ° C. and 85% RH. After that, it was confirmed with naked eyes whether there were bubbles, floating or peeling on the adhesive layer. As a result, it was evaluated that there were no bubbles or swells, and peeling was ◎, that there were almost no bubbles or swells, and peeling was ○, and that that bubbles or swells, and peeling occurred were x. (Evaluation of blister resistance). The results are shown in Table 2.

As can be seen from Table 2, the adhesive sheet obtained in the example was excellent in processability. Moreover, the adhesive layer obtained in the Example was excellent in uneven | corrugated follow-up before ultraviolet irradiation, and was excellent in moist-heat whitening resistance, durability, and blister resistance after ultraviolet irradiation.

[Industrial availability]

The active energy ray-curable adhesive sheet of the present invention is suitable for bonding to, for example, a display module, a protective plate having unevenness, and particularly a plastic plate.

Claims (14)

    An active energy ray-curable adhesive sheet, which is an adhesive sheet containing an active energy ray-curable adhesive layer, and is characterized in that: after the active energy ray is irradiated to the adhesive layer, the energy storage mold at 23 ° C. The ratio of the storage modulus to 23 ° C before irradiating the active energy ray to the adhesive layer is 1.1 to 10; both sides of the adhesive layer are sandwiched by two pieces of alkali-free glass having a thickness of 1.1mm. The laminated body obtained by irradiating the active energy ray through the glass on one side was stored in a hot and humid condition at 85 ° C and 85% RH for 240 hours, and then removed from the fog at 23 ° C and 50% RH at normal temperature and humidity. The value of the degree (%) minus the haze value (%) before the hot and humid conditions, and the increase in the haze value after the hot and humid conditions is less than 5.0 points.         An active energy ray-curable adhesive sheet, which is an adhesive sheet containing an active energy ray-curable adhesive layer, and is characterized in that: after the active energy ray is irradiated to the adhesive layer, the energy storage mold at 85 ° C. The ratio of the storage modulus to the adhesive layer at 85 ° C before irradiation with the active energy ray is 1.1 to 10; the two sides of the adhesive layer are sandwiched by two alkali-free glasses having a thickness of 1.1 mm. The laminated body obtained by irradiating the active energy ray through the glass on one side was stored in a hot and humid condition at 85 ° C and 85% RH for 240 hours, and then removed from the fog at 23 ° C and 50% RH at normal temperature and humidity. The value of the degree (%) minus the haze value (%) before the hot and humid conditions, and the increase in the haze value after the hot and humid conditions is less than 5.0 points.         According to the active energy ray-curable adhesive sheet according to item 1 or 2 of the scope of the patent application, the storage modulus of the adhesive layer at 23 ° C before irradiating the active energy ray is 0.01 to 0.2 MPa.         According to the active energy ray-curable adhesive sheet according to item 1 or 2 of the scope of the patent application, the storage modulus of the adhesive layer at 23 ° C. after irradiating the active energy ray is 0.02 to 2 MPa.         According to the active energy ray-curable adhesive sheet according to item 1 or 2 of the scope of the patent application, before the adhesive layer is irradiated with the active energy ray, the storage modulus at 85 ° C. is 0.01 to 0.1 MPa.         According to the active energy ray-curable adhesive sheet according to item 1 or 2 of the scope of the patent application, the storage modulus of the adhesive layer at 85 ° C. after the active energy ray is irradiated is 0.02 to 0.5 MPa.         According to the active energy ray-curable adhesive sheet according to item 1 or 2 of the scope of the patent application, the thickness of the adhesive layer is 50-400 μm.         The active energy ray-curable adhesive sheet according to item 1 or 2 of the scope of the patent application, wherein the adhesive sheet includes two release sheets, and the adhesive layer is in contact with the release surfaces of the two release sheets. The pattern is sandwiched by the above-mentioned release sheet.         A laminated body, characterized in that it comprises two rigid plates and an adhesive layer sandwiched by the two rigid plates, and the adhesive layer is any one of items 1 to 8 of the scope of patent application. The adhesive layer of the active energy ray-curable adhesive sheet is cured by irradiating the active energy ray.         The laminated body according to item 9 of the scope of patent application, wherein at least one of the hard plates has unevenness on a surface on the side of the adhesive layer.         The laminated body according to claim 10, wherein the unevenness is unevenness due to the presence or absence of a print layer.         The laminated body according to item 9 of the scope of patent application, wherein at least one of the hard plates includes a polarizing plate.         The laminated body according to item 9 of the scope of patent application, wherein at least one of the hard boards includes a plastic board.         The laminated body according to item 9 of the scope of the patent application, wherein one of the two hard boards is a display module or a part thereof, and the other of the two hard boards is on the side of the adhesive layer side, having Frame-shaped uneven protection plate.