TW201441330A - Adhesive sheet and laminate - Google Patents

Abstract

The present invention provides an adhesive sheet and the laminate with the excellent convex/concave compliance and containing the adhesive layer simultaneously having the excellent resistance to heat and humidity whitening and durability. To solve the above-mentioned issue, the present invention provides an adhesive sheet 1 constituted by thermally hardening of the adhesive composition containing the adhesive layer 11, containing the (meth) acrylate ester copolymer (A) having the average molecular weight of 200 thousands to 900 thousands and the monomer unit used to constitute the polymer containing 5 mass% to 20 mass% of the (meth) acrylic acid, the active energy line-curable ingredient (B), and the bridging agent (C), and with 50μm to 400 μm.

Description

Adhesive sheet and laminated body

The present invention relates to an adhesive sheet having an active energy ray-curable adhesive layer and a laminate obtained by using the adhesive layer of the adhesive sheet.

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

In such a display, generally, a protective panel is provided on the surface side of the display module. When the protective panel is deformed due to an external force between the protective panel and the display module, a gap is also formed, so that the deformed protective panel does not hit the display module.

However, the void as described above, that is, the air layer, if present, has a difference in refractive index between the protective panel and the air layer, and a reflection loss of light caused by a difference in refractive index between the air layer and the display module is large, and the image quality of the display is lowered. problem.

Therefore, research has proposed to improve the image quality of the display by filling the gap between the protective panel and the display module with the adhesive layer. However, the display module side of the protective panel may have a frame-shaped printed layer as the unevenness. If the adhesive layer does not follow the unevenness, the adhesive layer floats from the vicinity of the unevenness, whereby light reflection loss occurs. Therefore, the adhesive layer is required to have irregularity follow-up.

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

[Previous Technical Literature] [Patent Literature]

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

In Patent Document 1, it is intended to improve the unevenness of the storage by reducing the storage modulus at the normal temperature in the adhesive layer. However, if the storage modulus at normal temperature is lowered as described above, the storage modulus at a high temperature is excessively lowered, causing problems under endurance conditions. For example, after the high-temperature and high-humidity conditions are applied, when the temperature is returned to normal temperature and normal humidity, there is a problem that the adhesive layer is whitened or bubbles are generated in the vicinity of the unevenness.

The present invention has been made in view of the above circumstances, and it is an object of the invention to provide an adhesive sheet and a laminate having an adhesive layer which is excellent in unevenness and excellent in wet heat and whitening resistance and durability.

In order to achieve the above object, the present invention provides a bonding sheet characterized in that it has a weight average molecular weight of 200,000 to 900,000 as a monomer unit constituting a polymer, and contains 5 mass% to 20 mass. The (meth)acrylate copolymer (A) of the (meth)acrylic acid, the active energy ray-curable component (B), and the bridging agent (C) are thermally bridged, and have a thickness of 50 μm. 400 μm adhesive layer (Invention 1).

In the above invention (Invention 1), by thermally bridging the adhesive composition containing a (meth) acrylate copolymer having a small weight average molecular weight, the obtained adhesive layer has sufficient cohesive force and at the same time Excellent from sex. Further, the adhesive composition contains an active energy ray-curable component, and the adhesive layer is cured by irradiation with an active energy ray, and the thus-cured adhesive layer is excellent in moist heat whitening resistance and durability.

In the above invention (Invention 1), the content of the active energy ray-curable component (B) in the adhesive composition is preferably 1 in terms of 100 parts by mass of the (meth) acrylate copolymer (A). Parts by mass to 10 parts by mass (Invention 2).

In the above invention (Invention 1, Invention 2), the content of the bridging agent (C) in the adhesive composition is preferably 0.001 based on 100 parts by mass of the (meth) acrylate copolymer (A). Parts by mass to 2 parts by mass (Invention 3).

In the above invention (Invention 1 to Invention 3), the storage modulus at 23 ° C after the active energy ray is applied to the adhesive layer is at 23 ° C before the application of the active energy ray to the adhesive layer. The ratio of the storage modulus is preferably 1.1 to 2.5 (Invention 4).

In the above invention (Invention 1 to Invention 4), the storage modulus at 85 ° C after the active energy ray is applied to the adhesive layer is at 85 ° C before the application of the active energy ray to the adhesive layer. The ratio of the storage modulus is preferably 1.1 to 3.5 (Invention 5).

In the above invention (Invention 1 to Invention 5), the adhesive sheet includes two release sheets, and the adhesive layer is preferably sandwiched by the release sheet so as to be in contact with the release surface of the two release sheets (Invention 6) ).

Secondly, the present invention provides a laminated body characterized in that: The invention provides a two-piece hard plate and an adhesive layer which bonds the two rigid plates to each other, and the adhesive layer is cured by irradiating the adhesive layer of the adhesive sheet (Invention 1 to Invention 6) with an active energy ray. (Invention 7).

In the above invention (Invention 7), at least one of the hard plates may have irregularities on the surface on the side of the adhesive layer (Invention 8).

In the above invention (Invention 8), it is preferable that the unevenness is due to the unevenness of the printed layer (Invention 9).

In the above invention (Invention 7 to Invention 9), at least one of the hard plates may include a polarizing plate (Invention 10).

Further, in the above invention (Invention 7 to Invention 9), one of the two rigid plates is a display module or a part thereof, and the other of the two rigid plates is on the surface on the side of the adhesive layer. A protective plate having a frame-like unevenness is also possible (Invention 11).

In the above invention (Invention 7 to Invention 11), the total light transmittance of the adhesive layer is preferably 80% or more (Invention 12).

The adhesive layer of the adhesive sheet of the present invention is excellent in unevenness followability, and is excellent in moisture heat whitening resistance and durability after irradiation with an active energy ray. In the laminated body obtained by using such an adhesive sheet, even if the adhesive layer side has irregularities, the adhesive layer follows the unevenness, so that floating or bubbles are not generated in the vicinity of the unevenness. Further, in the laminate, the adhesive layer after the active energy ray irradiation is excellent in moisture heat whitening resistance and durability.

1‧‧‧bonding piece

11‧‧‧Adhesive layer

12a, 12b‧‧‧ peeling film

2‧‧‧Laminated body

21‧‧‧1st hard board

22‧‧‧2nd hard board

3‧‧‧Printing layer

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

Fig. 2 is a cross-sectional view showing a laminated body according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described.

[bonding sheet]

As shown in Fig. 1, in the bonding sheet 1 of the present embodiment, the two release sheets 12a and 12b are sandwiched between the two release sheets 12a and 12b and the release surfaces of the two release sheets 12a and 12b. The adhesive layer 11 of 12b is composed. In addition, the peeling surface of the peeling sheet in this specification is the surface which has the peeling property in the peeling sheet, and the surface which carried out the peeling process, and the surface which shows the peeling-

Adhesive layer

The adhesive layer 11 contains a (meth) acrylate copolymer having a weight average molecular weight of 200,000 to 900,000 as a monomer unit constituting the polymer and containing 5% by mass to 20% by mass of (meth)acrylic acid. The active energy ray formed by the thermal bridging of the adhesive composition of the active material (A), the active energy ray-curable component (B), and the bridging agent (C) (hereinafter referred to as "adhesive composition P") A curable adhesive layer. In the present specification, the term "(meth)acrylic acid" means both of acrylic acid and methacrylic acid. The same is true for other similar terms.

The adhesive layer 11 in the adhesive sheet 1 is formed by thermally bridging the adhesive composition P. Specifically, the (meth) acrylate copolymer (A) is bridged by the bridging agent (C). status. On the other hand, the active energy ray-curable component (B) is not cured, and is present in the adhesive layer 11 in a state of being bonded to the adhesive composition P. The active energy ray-curable component (B) is used when the adhesive sheet 1 is used In the case of a sticky substance, it is polymerized and cured when the active energy ray is irradiated to the adhesive layer 11.

(1) (meth) acrylate copolymer (A)

The (meth) acrylate copolymer (A) contains 5% by mass to 20% by mass of (meth)acrylic acid as a monomer unit constituting the polymer, and preferably contains 7% by mass to 15% by mass, particularly preferably It is contained in an amount of 8 mass% to 12 mass%. When the content of (meth)acrylic acid is in the above range, the bridging structure formed by the (meth) acrylate copolymer (A) and the bridging agent (C) is good, and the adhesive layer 11 is excellent in durability. Further, the content of (meth)acrylic acid is in the above range, and it is presumed that the cohesive force in the appearance of the adhesive can be improved, and the weight average molecular weight and bridging density of the (meth) acrylate copolymer (A) are suppressed. At the same time, since the stress relaxation property can be improved, the adhesive layer 11 is excellent in the unevenness of the adhesion. Further, the adhesive composition layer P containing the (meth)acrylic acid ester copolymer (A) having a content of (meth)acrylic acid in the above range, and the obtained adhesive layer 11 on the adhesive layer 11 After the curing, after performing high-temperature and high-humidity conditions (for example, leaving at 85 ° C and 85% RH for 240 hours), whitening at the time of returning to normal temperature and normal humidity is suppressed, that is, it is excellent in wet heat and whitening resistance. When the (meth) acrylate copolymer (A) contains the above amount of (meth)acrylic acid as a monomer unit, a certain amount of carboxyl groups remain in the obtained binder. The carboxyl group is a hydrophilic functional group. If the hydrophilic functional group is present in the binder in a quantitative amount, it is presumed that even if the adhesive is placed under high temperature and high humidity conditions, the adhesive is immersed in the adhesive under high temperature and high humidity conditions. The moisture is easily detached from the adhesive when it is returned to normal temperature and humidity, and as a result, whitening of the adhesive is suppressed.

In the (meth) acrylate copolymer (A), when the content of the (meth)acrylic acid as the monomer unit is less than 5% by mass, the adhesive layer 11 is specifically Don't get wet and heat whitening will be reduced. On the other hand, when the content of (meth)acrylic acid exceeds 20% by mass, the workability of the adhesive composition P is deteriorated.

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

Examples of the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylic acid. Base ester, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylate Octyl ester, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, (methyl) ) Acrylic stearyl group and the like. Among them, from the viewpoint of further improving the adhesion, a (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferable, and methyl (meth)acrylate and n-butyl (meth)acrylate are particularly preferable. 2-ethylhexyl (meth)acrylate. Further, these may be used alone or in combination of two or more.

The (meth) acrylate copolymer (A), as a monomer unit constituting the polymer, preferably contains 40% by mass to 95% by mass of an alkyl group having 1 to 20 carbon atoms of (meth)acrylic acid alkyl group. The ester is particularly preferably contained in an amount of from 80% by mass to 93% by mass, and more preferably from 88% by mass to 92% by mass.

The (meth) acrylate copolymer (A) may contain other monomers as a monomer unit constituting the polymer, as needed. Other monomers are preferably not included in order to prevent the reaction of (meth)acrylic acid from being affected. A monomer having a reactive functional group. Examples of such other monomers include (meth)acrylic acid alkoxyalkyl esters such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, and (methyl). a non-branching acrylamide such as an aliphatic ring-containing (meth) acrylate such as cyclohexyl group, acrylamide or methacrylamide, or N,N-dimethylamino (meth)acrylate A (meth) acrylate having a non-branching tertiary amino group such as an ethyl group or an N,N-dimethylaminopropyl group (meth)acrylate, vinyl acetate, styrene or 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 (meth) acrylate copolymer (A) has a weight average molecular weight of 200,000 to 900,000, preferably 250,000 to 700,000, particularly preferably 300,000 to 500,000. The weight average molecular weight in the present specification is a value in terms of polystyrene measured by a 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, Excellent bump tracking. When the weight average molecular weight of the (meth) acrylate copolymer (A) exceeds 900,000, the unevenness followability is lowered. On the other hand, when the weight average molecular weight of the (meth) acrylate copolymer (A) is less than 200,000, the durability of the adhesive layer 11 after the active energy ray irradiation is lowered.

Further, in the adhesive composition P, the (meth) acrylate copolymer (A) may be used alone or in combination of two or more.

(2) Active energy ray curable component (B)

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

The active energy ray-curable component (B) is not particularly limited as long as it does not inhibit the effects of the present invention, and is cured by irradiation with an active energy ray, and may be any of a monomer oligomer or a polymer. It can also be a mixture of them. Among them, a polyfunctional acrylate monomer having a molecular weight of less than 1,000 which is excellent in compatibility with the (meth) acrylate copolymer (A) or the like can be preferably used.

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 neopenta-2. Alcohol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(methyl) Acrylate, dicyclopentyl di(meth) acrylate, caprolactone modified dicyclopentenyl di(meth) acrylate, ethylene oxide modified di(meth) acrylate, di Bifunctional type such as acryloxyethyl)isocyanate or allylated 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(propylene oxyoxyethyl) a trifunctional type such as isocyanate or ε-caprolactone modified tris(2-(meth)acryloxyethyl)isocyanate; diglycerin tetra(meth)acrylate, pentaerythritol (Methyl) acrylates such as tetrafunctional; propanoic acid-modified dipentaerythritol penta (meth) acrylate, trifunctional 5; dipentaerythritol hexa (meth) acrylate, caprolactone-modified A 6-functional type such as dipentaerythritol hexa(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 can also be used. The acrylate oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such an acrylate-based oligomer include polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polybutadiene acrylates, and fluorenone acrylates.

Here, as the polyester acrylate oligomer, for example, a hydroxyl group or a polyester of a polyester oligomer having a hydroxyl group at both terminals obtained by polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol can be used by using (meth)acrylic acid. Alternatively, it may be obtained by esterifying a hydroxyl group at the terminal of the oligomer obtained by adding an alkylene oxide to a polyvalent carboxylic acid with (meth)acrylic acid. The epoxy acrylate oligomer can be, for example, reacted and esterified on a bisphenol type epoxy resin having a relatively low molecular weight and an oxirane ring of a novolac type epoxy resin. And get it. Further, a carboxy-modified epoxy acrylate oligomer obtained by partially modifying the epoxy acrylate oligomer with a dibasic carboxylic acid anhydride can also be used. The urethane acrylate oligomer can be obtained, for example, by esterifying a urethane oligomer obtained by a reaction of a polyether polyol and a polyester polyol with a polyisocyanate with (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 alone or in combination. Use two or more combinations.

Further, as the active energy ray-curable component (B), an additive acrylate-based polymer obtained by introducing a group having a (meth) acrylonitrile group into a side chain can also be used. Such an additive acrylate-based polymer can have a (meth) acrylonitrile group and a bridging functional group by using a copolymer of a (meth) acrylate and a monomer having a bridging functional group in the molecule. The compound of the reactive group is obtained by reacting a part of the bridging functional group of the copolymer.

The (meth) acrylate is preferably an alkyl (meth) acrylate having an alkyl group and having 1 to 20 carbon atoms, and examples thereof include methyl (meth)acrylate and ethyl (meth)acrylate. Base ester, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (methyl) ) 2-ethylhexyl acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, ( Cetylmethyl methacrylate, 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 at least one selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a guanamine group as a functional group. Examples of the monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth)acrylic acid 2. Hydroxyalkyl (meth)acrylate such as -hydroxybutyl ester, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate; N-methylol acrylamide Acrylamide; monomethylaminoethyl (meth)acrylate, ( (meth)acrylic acid monoalkylaminoalkyl group such as monoethylaminoethyl methacrylate, monomethylaminopropyl (meth) acrylate or monoethylaminopropyl (meth) acrylate Ester; an ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid or citraconic acid. These monomers may be used singly or in combination of two or more.

As the compound having a group reactive with a (meth)acryl fluorenyl group and a bridging functional group, for example, 2-methylpropenyloxyethyl isocyanate or 2-(0-[1] methacrylate can be preferably used. '-Methylpropylenepropaneamino]carboxyamino)ethyl, 2-[(3,5-dimethylpyridyl)carbonylamino]ethyl methacrylate, 1,1-(bispropenyloxymethyl) Ethyl isocyanate, 2-propenyloxyethyl isocyanate, 2-propenyloxyethyl succinate, 2-propenyl oxiranyl hexahydrophthalate, ω-carboxy-polycaprolactone Acrylate, monohydroxyethyl phthalate, 2-hydroxy-3-phenoxypropyl acrylate, and the like. These compounds may be used singly or in combination of two or more.

The weight average molecular weight of the above-mentioned additive acrylate polymer is preferably from 50,000 to 900,000, particularly preferably from about 100,000 to 500,000.

The active energy ray-curable component (B) may be selected from the above-mentioned polyfunctional acrylate monomer, acrylate oligomer, and additive acrylate polymer, or two or more types may be used. When used in combination, it can also be used in combination with active energy ray-curable components other than these.

The content of the active energy ray-curable component (B) in the adhesive composition P is preferably from 1 part by mass to 10 parts by mass per 100 parts by mass of the (meth) acrylate copolymer (A), and particularly preferably It is 2 parts by mass to 8 parts by mass, and more preferably 3 parts by mass to 7 parts by mass. Active energy ray curable component (B) If the amount is less than 1 part by mass, the durability of the adhesive layer 11 after the active energy ray irradiation may be lowered. When the content of the active energy ray-curable component (B) exceeds 10 parts by mass, the wet heat whitening resistance of the adhesive layer 11 after the active energy ray irradiation may be deteriorated.

(3) bridging agent (C)

The adhesive composition P is bridged with a bridging agent (C) to form a three-dimensional network structure, thereby improving the cohesive force of the obtained adhesive. In addition, the adhesive may be imparted with durability after irradiation with the active energy ray.

The bridging agent (C) is a reactive bridging agent which is reactive with respect to the reactive functional group (carboxyl group of (meth)acrylic acid of a monomer unit) which the (meth)acrylate copolymer (A) has. Examples thereof include an isocyanate bridging agent, an epoxy bridging agent, an amine bridging agent, a melamine bridging agent, an aziridine bridging agent, an anthraquinone bridging agent, an aldehyde bridging agent, an oxalate-type bridging agent, Metal alkoxide bridging agents, metal chelate bridging agents, metal salt bridging agents, ammonium salt bridging agents, and the like. The bridging agent (C) may be used alone or in combination of two or more.

Among them, 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 is preferable as the bridging agent (C), and an epoxy-based bridging agent is particularly preferably used. The adhesive layer 11 using an epoxy-based bridging agent is excellent in heat resistance and is not easily yellowed, and is suitable for optical use.

Examples of the epoxy-based bridging agent include 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane and N,N,N',N'-tetraglycidyl group. Toluene diamine, ethylene glycol diglycidyl ether, 1,6-hexanediol Glycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidylamine, and the like.

The isocyanate bridging agent is a bridging agent containing at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as methylphenyl diisocyanate, diphenylmethane diisocyanate and xylene diisocyanate, and aliphatic polyisocyanates such as hexamethylene diisocyanate and isophor. Examples of the alicyclic polyisocyanate such as keto diisocyanate and hydrogenated diphenylmethane diisocyanate, and the biuret or isocyanate of these, and further examples thereof include ethylene glycol, propylene glycol, neopentyl glycol, and trimethylolpropane. An additive such as castor oil or the like which is a reactant containing a low molecular weight active hydrogen compound.

The content of the bridging agent (C) in the adhesive composition P is preferably 0.001 parts by mass to 2 parts by mass, particularly preferably 0.01 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer (A). 1 part by mass, more preferably 0.02 part by mass to 0.3 part by mass. When the content of the bridging agent (C) is 0.001 part by mass or more, the adhesive after the active energy ray irradiation can provide an effect of improving durability. When the content of the bridging agent (C) exceeds 2 parts by mass, the degree of bridging is excessive, and the unevenness of the obtained adhesive may be lowered. Further, the carboxyl group of the (meth) acrylate copolymer (A) is largely reacted with the bridging agent (C), and the amount of the carboxyl group remaining in the binder is small, and the above-mentioned moist heat whitening property may be lowered.

(4) Photopolymerization initiator (D)

When the ultraviolet ray is used as the active energy ray to be applied to the adhesive layer 11, the adhesive composition P further preferably contains a photopolymerization initiator (D). By containing the photopolymerization initiator (D), the active energy ray-curable component (B) can be effectively cured, and the polymerization curing time and activity energy can be reduced. The amount of exposure of the measuring line.

Examples of such a photopolymerization initiator (D) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and 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-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl] -2-Merlin-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone 4,4'-Diethylaminobenzophenone, dichlorobenzophenone, 2-methyloxime, 2-ethylhydrazine, 2-tert-butylhydrazine, 2-aminopurine, 2 -methyl ketoxime, 2-ethyl ketoxime, 2-chloroseptone, 2,4-dimethyl ketoxime, 2,4-diethyl ketoxime, benzyl dimethyl condensate Ketone, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2 , 4,6-trimethylbenzimidyl-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 of from 2 parts by mass to 15 parts by mass, particularly preferably from 4 parts by mass to 12 parts by mass, per 100 parts by mass of the active energy ray-curable component (B).

(5) Various additives

The adhesive composition P may be added with various additives commonly used in acrylic adhesives, such as a decane coupling agent, a charge preventing agent, an adhesion-imparting agent, an oxidation preventing agent, an ultraviolet absorber, and light stabilization, as needed. Agent, softener, filler, refractive index modifier, and the like.

As a decane coupling agent, it has at least one alkoxy group in the molecule The organic ruthenium compound of formoxane preferably has good compatibility with the (meth) acrylate copolymer (A). Further, when the adhesive sheet 1 is used for optical use, it is preferably a light-transmitting decane coupling agent.

The decane coupling agent may, for example, be a polymerizable unsaturated group-containing oxime compound such as vinyl trimethoxy decane, vinyl triethoxy decane or methacryl methoxypropyl trimethoxy decane, or - an oxime compound having an epoxy structure such as glycidoxytrimethoxydecane or 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, 3-mercaptopropyltrimethoxydecane, 3 a mercapto group-containing hydrazine compound such as mercaptopropyltriethoxydecane or 3-mercaptopropylmethyldimethoxydecane, 3-aminopropyltrimethoxydecane, N-(2-aminoethyl)- An amino group-containing hydrazine compound such as 3-aminopropyltrimethoxydecane or N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, 3-chloropropyltrimethoxydecane, 3-isocyanate propyl triethoxy decane, or a mixture of at least one of these and methyl triethoxy decane, ethyl triethoxy decane, methyl trimethoxy decane, ethyl trimethoxy decane, etc. A condensate of an alkyl ruthenium compound or the like. These may be used alone or in combination of two or more.

The amount of the decane coupling agent to be added is preferably 0.01 parts by mass to 1.0 part by mass, and particularly preferably 0.05 parts by mass to 0.5 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer (A).

(6) Manufacture of adhesive composition

The adhesive composition P can be obtained by producing the (meth) acrylate copolymer (A), the obtained (meth) acrylate copolymer (A), the active energy ray-curable component (B), and a bridging agent ( C) mixing is carried out, and at the same time, a photopolymerization initiator (D) and/or an additive is added as needed to manufacture.

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

Examples of the polymerization initiator include an azo compound and an organic peroxide, and two or more kinds thereof can be used at the same time. 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-cyanoshikimate), 2,2'-azobis(2-hydroxyl) Methylpropionitrile), 2,2'-azobis[2-(2-misoline-2-yl)propane], and the like.

Examples of the organic peroxide include benzamidine peroxide, t-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, and di-n-propyl peroxygen. Dicarbonate, bis(2-ethoxyethyl)peroxydicarbonate, tert-butyl peroxy neopentate, tert-butyl peroxypivalate, (3,5,5-trimethyl Benzyl) peroxide, dipropylene peroxide, diethyl hydrazine peroxide, and the like.

Further, in the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by mixing a chain shifting agent such as 2-mercaptoethanol.

After obtaining the (meth) acrylate copolymer (A), in (meth)acrylic acid In the solution of the ester copolymer (A), the active energy ray-curable component (B), the bridging agent (C), and, if necessary, a polymerization initiator (D) and an additive are added, and the mixture is 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 treatment. Further, this heat treatment can also serve as a drying treatment after the application of the adhesive composition P.

The heating temperature of the heat treatment is preferably from 50 ° C to 150 ° C, particularly preferably from 70 ° C to 120 ° C. Further, the heating time is preferably from 10 seconds to 10 minutes, particularly preferably from 50 seconds to 2 minutes. In particular, it is preferable to retain the ripening period of about 1 to 2 weeks at room temperature (for example, 23 ° C, 50% RH) after the heat treatment.

The (meth) acrylate copolymer (A) is well bridged by the above-described heat treatment (and aging) involving the bridging agent (C).

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

When the thickness of the adhesive layer 11 is less than 50 μm, sufficient unevenness tracking cannot be obtained, and if the thickness of the adhesive layer 11 exceeds 400 μm, workability is lowered.

2. Stripping 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, and a vinyl chloride copolymer film. Polyethylene terephthalate Ester film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene-(meth)acrylic copolymer film, An ethylene-(meth)acrylate copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film, or the like. In addition, bridging films of these can also be used. Further, it is also possible to laminate these films.

It is preferable that the peeling surface of the peeling sheets 12a and 12b (particularly the surface which contact|connects the adhesive bond layer 11) is the peeling process. Examples of the release agent used for the release treatment include a release agent of an alkyd, an anthrone, a fluorine, an unsaturated polyester, a polyolefin, and a wax. In the release sheets 12a and 12b, it is preferable that one of the release sheets is a heavy release type release sheet having a large peeling force, and the other release sheet is a light release type release sheet having 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. Manufacture of adhesive sheets

As an example of the production of the adhesive sheet 1, the coating liquid of the adhesive composition P is applied and heat-treated on the peeling surface of one of the release sheets 12a (or 12b), and the adhesive composition P is thermally bridged. After the coating layer is formed, the peeling 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.

As another example of the production of the adhesive sheet 1, the coating liquid of the adhesive composition P is applied and heated on the peeling surface of one of the release sheets 12a. After the treatment, the adhesive composition P is thermally bridged to form a coating layer, and a release sheet 12a to which the coating layer adheres is obtained. In addition, the coating liquid of the adhesive composition P is applied and heat-treated on the peeling surface of the other release sheet 12b, and the adhesive composition P is thermally bridged to form a coating layer, thereby obtaining peeling of the coating layer. Sheet 12b. Thereafter, the release sheet 12a to which the coating layer is adhered is bonded to the release sheet 12b to which the coating layer is attached, and the coating layers on both sides 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 laminated coating layer directly becomes the adhesive layer 11. Thereby, the above-mentioned adhesive sheet 1 is obtained.

As a method of applying the coating liquid of the above-mentioned adhesive composition P, for example, a bar coating method, a knife coating method, a roll coating method, a plate coating method, a die 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 active energy ray is applied to the adhesive layer 11 to the storage modulus at 23 ° C before the application of the active energy ray to the adhesive layer 11 (active energy ray irradiation) The storage modulus after the storage/expansion of the active energy ray is preferably from 1.1 to 2.5, particularly preferably from 1.2 to 2.0, still more preferably from 1.3 to 1.7. In addition, the storage modulus in this specification is a value measured by the torsion shear method based on JIS K7244-6 at the measurement frequency of 1 Hz.

As described above, after the active energy ray irradiation (after curing), the storage modulus of the adhesive layer 11 at 23 ° C increases, and the cured adhesive layer 11 is excellent in durability at normal temperature.

Further, the ratio of the storage modulus at 23 ° C after the active energy ray is applied to the adhesive layer 11 to the storage modulus at 85 ° C before the application of the active energy ray to the adhesive layer 11 (active energy ray) Storage modulus / active energy line after irradiation The storage modulus before the injection is preferably from 1.1 to 3.5, particularly preferably from 1.3 to 2.5, still more preferably from 1.4 to 2.0.

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

When the ratio of the above storage modulus at 23 ° C or 85 ° C is less than 1.1, the effect of improving the durability as described above may not be obtained. On the other hand, if the ratio of the storage modulus at 23 ° C exceeds 2.5, or the ratio of the storage modulus at 85 ° C exceeds 3.5, the adhesion of the cured adhesive layer 11 is lowered, and there may be no possibility. Get full durability.

The storage modulus of the adhesive layer 11 before the 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 further preferably 0.07 MPa to 0.1 MPa. Further, the storage modulus of the adhesive layer 11 before the active 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 more preferably 0.02 MPa to 0.04 MPa. The adhesive layer 11 before the active energy ray irradiation has the storage modulus as described above, and is excellent in 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 0.5 MPa, particularly preferably 0.05 MPa to 0.3 MPa, and more preferably 0.09 MPa to 0.2 MPa. Further, the storage modulus of the adhesive layer 11 after the active energy ray irradiation at 85 ° C is preferably 0.02 MPa to 0.2 MPa, particularly preferably 0.02 MPa to 0.1 MPa, and more preferably 0.03 MPa to 0.05 MPa. The adhesive layer 11 after the active energy ray irradiation has excellent storage durability by having the storage modulus as described above.

In the above-mentioned adhesive sheet 1, since the adhesive layer 11 before the active energy ray irradiation is excellent in the unevenness followability, when the adherend has irregularities, the unevenness and the adhesive layer 11 are hard to appear. The voids or bubbles may occur, and the adhesive layer 11 may fill the irregularities. Further, the adhesive layer 11 is cured by irradiation with an active energy ray, and is excellent in wet heat whitening resistance and durability.

The adhesive layer 11 of the adhesive sheet 1 of the present embodiment is preferably used to bond two rigid plates to each other as will be described later.

[layered body]

As shown in FIG. 2, in the laminated body 2 of the present embodiment, the first hard plate 21, the second hard plate 22, and the first hard plate 21 and the second hard plate 22 are bonded to each other. The adhesive layer 11 is composed of. Further, in the laminated body 2 of the present embodiment, the first hard plate 21 has irregularities on the surface on the side of the adhesive layer 11, and specifically has irregularities due to the printed 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 bonded. Further, the first hard plate 21 and the second hard plate 22 may be the same material or different materials.

Examples of the first hard plate 21 and the second hard plate 22 include, for example, a glass plate, a plastic plate, a metal plate, a semiconductor plate, and the like, and a laminated body such as a display module or a solar cell module. Hard products, etc.

The glass plate is not particularly limited, and examples thereof include chemically tempered glass, flawless glass, quartz glass, soda lime glass, barium glass, aluminosilicate glass, lead glass, borosilicate glass, and bismuth. Boron silicate glass and the like. The thickness of the glass plate is not particularly limited, but is usually 0.1 mm to 5 mm, which is excellent. Choose 0.2mm~2mm.

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, preferably 0.4 mm to 3 mm.

Further, one or both surfaces of the glass plate and the plastic plate may be provided with various functional layers (a transparent conductive film, a metal layer, a ceria layer, a hard coat layer, an anti-glare layer, etc.), or an optical member may be laminated.

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

Further, examples of the display module include a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroplating luminescent (organic EL) module, and electronic paper. Further, in these display modules, a laminate of the above-described glass plate, plastic plate (film), optical member, and the like is usually used. For example, the LCD module has a polarizing plate laminated, and the polarizing plate forms a side surface of the LCD module.

In the laminated body 2 of the present embodiment, at least one of the first hard plate 21 and the second hard plate 22 preferably has a polarizing plate. In the laminated body 2 of the present embodiment, the second hard plate 22 is preferably a display module or a part thereof (for example, an optical member such as a polarizing plate), and the first hard plate 21 is a protective plate made of a glass plate or the like. At this time, the printed layer 3 is generally formed in a frame shape on the side of the adhesive layer 11 of the first hard plate 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. ~45 μm, particularly preferably 5 μm to 35 μm, more preferably 7 μm to 25 μm, still more preferably 7 μm to 15 μm.

Further, the thickness (height of the unevenness) of the printed layer 3 is preferably from 3% to 30%, particularly preferably from 3.2% to 20%, and more preferably from 3.5% to 15%, of the thickness of the adhesive layer 11. Thereby, the adhesive layer 11 can surely follow the unevenness of the printed layer 3, and floating, bubbles, and the like do not occur near the unevenness.

In the adhesive layer 11 of the laminated body 2 of the present embodiment, the adhesive layer 11 in the adhesive sheet 1 is cured by irradiation with an active energy ray. Here, the active energy ray means that the electromagnetic wave or the charged particle beam has an energy quantum, and specific examples thereof include ultraviolet rays and electron beams. Ultraviolet rays which are easy to handle are also particularly preferable among the active energy rays.

The irradiation of ultraviolet rays can be carried out by a high pressure mercury lamp, a Fusion H lamp, a xenon lamp or the like, and the irradiation amount of the ultraviolet rays is preferably about 50 mW/cm ² to 1000 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 1000 KRaD.

When the active energy ray is applied to the adhesive layer 11 in the adhesive sheet 1, the active energy ray-curable component (B) is polymerized and cured. The adhesive layer 11 which is cured by irradiation with an active energy ray is excellent in durability and wet heat whitening resistance.

As an example, the laminated body 2 is produced by first peeling off one of the release sheets 12a (or 12b) of the adhesive sheet 1, and exposing the adhesive layer 11 and the first hard board 21 (or the second hard type) in which the adhesive sheet 1 is exposed. Plate 22) is fitted. Next, the other release sheet 12b (or 12a) is peeled off from the adhesive layer 11 of the adhesive sheet 1, and the adhesive sheet 1 is removed. The exposed adhesive layer 11 is bonded to the second hard board 22 (or the first hard board 21).

When the adhesive layer 11 and the first hard plate 21 are bonded in the above-described steps, the adhesive layer 11 is excellent in unevenness, and the gap between the unevenness of the printed layer 3 and the adhesive layer 11 is hard to occur. The adhesive layer 11 can fill the unevenness.

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

In the laminated body 2, the adhesive layer 11 before the irradiation of the active energy ray is excellent in the unevenness of the adhesion, and it is difficult to generate voids or bubbles between the unevenness of the printed layer 3 and the adhesive layer 11. In addition, after the high-temperature and high-humidity conditions are applied, the adhesive layer 11 which is solidified by the irradiation of the active energy ray is suppressed from whitening at normal temperature, and is excellent in moist heat whitening resistance. In addition, even when the high-temperature and high-humidity conditions are applied, the adhesive layer 11 which is irradiated with the active energy ray can prevent bubbles from occurring in the vicinity of the unevenness, and is excellent in durability.

The excellent moist heat whitening resistance of the adhesive layer 11 which is cured by irradiation of the active energy ray can be evaluated as follows. For example, the both surfaces of the adhesive layer 11 are sandwiched between two sheets of non-twisted glass having a thickness of 1.1 mm, and the illuminating energy and the amount of active energy of the light are irradiated on at least one side of the untwisted glass to obtain a laminated body. The laminate was stored under the conditions of 85 ° C and 85% RH (humid heat conditions) for 240 hours, and then taken out at 23 ° C and 50% RH under normal temperature and normal humidity. At this time, it was confirmed that the degree of whitening of the above-mentioned adhesive layer 11 was small.

The degree of whitening described above can be quantitatively evaluated by the haze value. Specifically, the haze value before the wet heat condition can be subtracted from the haze value (%) (the value measured based on JIS K7136:2000, the same applies hereinafter) from the above-mentioned laminated body under the moist heat condition. The value of (%) (the haze value after the wet heat condition was increased) was evaluated. The haze value after the moist heat condition is increased, preferably less than 5.0 points, and particularly preferably less than 1.0 point. Further, in the above evaluation, it is preferable that the haze value is almost 0% as the above-mentioned flawless glass. Moreover, the haze value of the adhesive layer after the above-mentioned moist heat condition is preferably 1.0% or less, particularly preferably 0.9% or less, and further preferably 0.8% or less.

In addition, the total light transmittance (value measured based on JIS K7361-1:1997) of the above-mentioned adhesive layer 11 is preferably 80% or more, particularly preferably 90% or more, and further preferably 99% or more. When the total light transmittance is 80% or more, the transparency is high, and it is suitable for optical use. Such a total light transmittance is easily achieved by using an epoxy-based bridging agent which is difficult to yellow the adhesive layer 11 as a bridging agent (C). Further, the total light transmittance of the adhesive layer 11 hardly changes before and after the irradiation of the active energy ray.

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

For example, either one of the release sheets 12a and 12b of the adhesive sheet 1 can be omitted. Further, the first hard plate 21 may have irregularities other than the printed layer 3 or may have no irregularities. Further, not only the first hard plate 21 but also the side of the adhesive layer 11 of the second hard plate 22 may have irregularities.

[Examples]

The present invention will be specifically described by the following examples, but the scope of the present invention is not limited by the examples and the like.

[Example 1]

1. Modulation of (meth) acrylate copolymer

90 parts by mass of n-butyl acrylate, 10 parts by mass of acrylic acid, 200 parts by mass of ethyl acetate, and 2,2'-even were placed in a reaction vessel including a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube. 0.18 parts by mass of nitrogen diisobutyronitrile, and the air in the above reaction vessel was replaced with nitrogen. The reaction solution was heated to 60 ° C while stirring in a nitrogen atmosphere, and the reaction was allowed to proceed for 16 hours, and then cooled to room temperature. Here, the molecular weight of a part of the obtained solution was measured by the method described later, and it was confirmed that the (meth)acrylate copolymer (A) having a weight average molecular weight of 400,000 was formed.

2. Modulation of adhesive composition

100 parts by mass of the (meth) acrylate copolymer (A) obtained in the above step (1) (solid content conversion value; the same applies hereinafter); as the active energy ray-curable component (B), polyethylene glycol Diacrylate (trade name "NK ester A-400", manufactured by Shin-Nakamura Chemical Co., Ltd., solid content concentration: 100% by mass) 5 parts by mass; as epoxy type bridging agent (C), 1,3-double (N) , N-diglycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD-C", solid content concentration: 100% by mass), 0.06 parts by mass; as a decane coupling agent, 3- 0.2 parts by mass of glycidoxytrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403"); as a photopolymerization start to dilute the solid content concentration to 50% by mass in methyl ethyl ketone (D), 0.25 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Corporation, trade name "IRGACURE 184") was mixed, thoroughly stirred, and diluted with methyl ethyl ketone to obtain a solid content concentration. It is a coating solution of 39% by mass of the adhesive composition.

Here, the matching of the adhesive composition is shown in Table 1. In addition, The details of the abbreviations and the like described in Table 1 are as follows.

[(Meth)acrylate copolymer]

BA: n-butyl acrylate

AA: Acrylic

[Bridge agent]

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

Isocyanate: Trimethylolpropane modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "CORONATEL")

3. Manufacture of adhesive sheets

The coating solution of the obtained adhesive composition was subjected to a peeling-off peeling sheet which was subjected to a release treatment on one surface of a polyethylene terephthalate film with an anthrone-based release agent (Lindeaceae) The peeling-treated surface of the product, the product name "SP-PET752150" was applied by a knife coater to a thickness of 100 μm after drying, and then a coating layer was formed by heat treatment at 100 ° C for 4 minutes. Similarly, the coating solution of the obtained adhesive composition was subjected to a peeling-off peeling sheet which was peeled off with an anthrone-based release agent on one side of a polyethylene terephthalate film (Linde) The peeling-treated surface of the product type "SP-PET382120" manufactured by Kokusai Co., Ltd. was coated with a knife coater to have a thickness of 100 μm after drying, and then a coating layer formed by heat treatment at 100 ° C for 4 minutes.

Then, the heavy-peelable release sheet to which the coating layer obtained as described above and the light release-type release sheet to which the coating layer obtained is adhered are bonded, and the coating layers on both sides are brought into contact with each other, and are aged at 23 ° C and 50% RH. 7 days, manufactured by a heavy release type release sheet/adhesive layer (thickness: 200 μm) / light release type release sheet The formed adhesive sheet is formed. In addition, the thickness of the adhesive layer is a value measured based on JIS K7130 using a static pressure thickness gauge (manufactured by Teclock Co., Ltd., trade name "PG-02").

[Examples 2 to 9, Comparative Examples 1 to 3]

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 the active energy ray-curable component (B), and the like The amount, the type of bridging agent (C), the amount of collocation, the amount of photopolymerization initiator (D), the amount of decane coupling agent, and the thickness of the adhesive layer are changed as shown in Table 1, and Example 1 was operated in the same manner to produce a bonding sheet. Further, in the second embodiment, the heavy release type release sheet to which the coating layer adhered and the light release type release sheet to which the coating layer adhered were formed so that the thickness of each coating layer was 75 μm and the thickness of the adhesive layer was 150 μm. . Further, in Example 8, as the active energy ray-curable component (B), ε-caprolactone-modified tris(2-propenyl methoxyethyl) isocyanate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK" In the case of the active energy ray-curable component (B), pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK" was used as the active energy ray-curable component (B). Ester A-TMM-3L", triester: 55 mass%, solid content concentration: 100% by mass).

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

<Measurement conditions>

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

‧GPC column (the following sequence is passed): Tosoh company

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

‧ Determination of solvent: tetrahydrofuran

‧Measurement temperature: 40 ° C

[Test Example 1] (Measurement of storage modulus)

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

For the above sample, the storage modulus (MPa) was measured under the following conditions using a viscoelasticity measuring apparatus (MCR300, manufactured by Physica Co., Ltd.) based on JIS K7244-6 under the following conditions.

Measurement frequency: 1 Hz

Measurement temperature: 23 ° C, 85 ° C

In addition, the same sample as above was irradiated with ultraviolet rays under the following conditions using an ultraviolet irradiation device (trade name "EYEGRANDAGEECS-401GX type" manufactured by Eyegraphics Co., Ltd.) to cure the adhesive layer, and a sample after ultraviolet irradiation was obtained. The sample after the obtained ultraviolet ray irradiation was subjected to the same operation as the sample before the ultraviolet ray irradiation, and the storage modulus (MPa) was measured.

[UV irradiation conditions]

‧Light source: high pressure mercury lamp

‧Light quantity: 1000mJ/cm ²

‧ Illuminance: 200mW/cm ²

In the above measurement results, the storage modulus after ultraviolet irradiation was calculated, and the ratio of the storage modulus before ultraviolet irradiation at 23 ° C and 85 ° C (storage modulus after ultraviolet irradiation / ultraviolet irradiation) Pre-storage modulus) These measurement results and calculation results are shown in Table 2.

[Test Example 2] (Evaluation of moisture and heat resistance)

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

Then, the laminate was stored under humid heat conditions of 85 ° C and 85% RH for 240 hours. Then, the temperature was normalized to normal temperature and humidity of 23 ° C and 50% RH, and the haze value was measured based on JIS K7136:2000 using a haze meter (product name "NDH2000" manufactured by Nippon Denshoku Industries Co., Ltd.). %). In addition, the haze value was measured within 30 minutes after returning the laminated body to normal temperature and normal humidity.

From the above results, the haze value before the moist heat condition was subtracted from the haze value after the moist heat condition, and the haze value (dot) after the moist heat condition was calculated. When the haze value after the wet heat condition is increased by less than 1.0 point, the wet heat resistance is good (○), and the haze value after the wet heat condition is increased by more than 1.0 point and less than 5.0 points, the wet heat whitening property is within an appropriate value (Δ), and the damp heat condition When the haze value was increased by more than 5.0 points, it was evaluated by the wet heat whitening resistance (×). The results are shown in Table 2.

[Test Example 3] (concavity and follow-up, durability test)

(a) Production of samples for evaluation

UV-curable ink (manufactured by Imperial Ink Co., Ltd., trade name "POS-911 ink" on the surface of a glass plate (manufactured by NSG PRECISION Co., Ltd., trade name "Corning Glass, Eagle XG", vertical 90 mm × lateral 50 mm × thickness 0.5 mm) ” Screen printing was performed on a frame shape (outer shape: longitudinal direction 90 mm × lateral direction 50 mm, thickness 5 mm) so that the coating thickness was 8 μm and 15 μm. Next, ultraviolet rays (80 W/cm ² , metal halide lamp 2 盏, lamp height 15 cm, belt speed 10 m/min to 15 m/min) were irradiated, and the printed ultraviolet curable ink was cured to have printed unevenness (height of unevenness). : 8 μm and 15 μm) of the uneven adhesion glass plate.

The adhesive sheet obtained in the examples or the comparative examples was cut into a shape of 90 mm in the longitudinal direction and 50 mm in the transverse direction, and the light-peelable release sheet was removed to expose the adhesive layer. Then, using a laminator (manufactured by Fuji Co., Ltd., trade name "LPD3214"), the adhesive layer was completely covered by the frame-like printing, and the adhesive sheet was molded on the uneven-attached glass plate.

Thereafter, the following samples for evaluation (1) and (2) were prepared.

(1) After the above-mentioned plastic sealing, the heavy release type release sheet was peeled off, and a glass plate (manufactured by NSG PRECISION Co., Ltd., trade name "Corning Glass, Eagle XG", longitudinal direction 90 mm × lateral direction 50 mm × was peeled off on the exposed adhesive layer. The thickness of 0.5 mm) was molded by the above-mentioned laminator to prepare a sample for evaluation.

(2) A glass plate (manufactured by NSG PRECISION Co., Ltd., trade name "Corning Glass, Eagle XG", vertical 90 mm × lateral 50 mm × thickness 0.5 mm) was inserted into the adhesive, and a hard plate in which a polarizing plate was laminated was prepared. After that, in the concave-convex adhesion glass plate obtained in the above step, the plastic-bonded adhesive sheet is peeled off. The sheet was peeled off, and the exposed adhesive layer and the polarizing plate surface of the hard plate were brought into contact with each other, and both sides were plastic-sealed by the above-mentioned laminator to prepare a sample for evaluation.

(b) Concavity follow-up (initial) evaluation

The obtained evaluation samples (1) and (2) were pressurized at 0.5 MPa and 50 ° C for 30 minutes in a pressure cooker manufactured by Kurihara Seisakusho Co., Ltd. Then, it was visually confirmed whether or not there was a bubble on the adhesive layer (especially due to the unevenness of the printed layer). The initial irregularities following the absence of air bubbles were good (○), and the initial irregularities following the bubbles (×) were evaluated. The results are shown in Table 2.

(c) Evaluation of durability (concave tracking after durability)

Next, the samples (1) and (2) for evaluation described above were stored under humid heat conditions of 85 ° C and 85% RH for 240 hours. Thereafter, it was confirmed with the naked eye whether or not there was a bubble on the adhesive layer (especially due to the unevenness of the printed layer). The durability (the obscuration-resistance after durability) of the air bubbles was not good (○), and the durability (the unevenness after the endurance) of the air bubbles was evaluated (×). The results are shown in Table 2.

[Test Example 4] (total light transmittance measurement)

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

【Table 1】

【Table 2】

As is clear from Table 2, the adhesive layer obtained in the examples was excellent in the tracking followability before ultraviolet irradiation, and was excellent in moisture heat whitening resistance and durability after ultraviolet irradiation.

[Industrial Availability]

The adhesive sheet of the present invention is suitably used for bonding to, for example, a display module and a protective sheet having irregularities.

1‧‧‧bonding piece

11‧‧‧Adhesive layer

12a, 12b‧‧‧ peeling film

Claims (12)

An adhesive sheet comprising a (meth) acrylate copolymer containing a weight average molecular weight of 200,000 to 900,000 as a monomer unit constituting a polymer and containing 5 to 20% by mass of (meth)acrylic acid ( A) An adhesive layer having a thickness of 50 μm to 400 μm, which is composed of an adhesive structure of an active energy ray-curable component (B) and a bridging agent (C). The adhesive sheet according to the above aspect of the invention, wherein the content of the active energy ray-curable component (B) in the adhesive composition is relative to the (meth) acrylate copolymer (A) 100 parts by mass, from 1 part by mass to 10 parts by mass. The adhesive sheet according to the above aspect of the invention, wherein the content of the bridging agent (C) in the adhesive composition is 100 parts by mass based on the (meth) acrylate copolymer (A). It is 0.001 parts by mass to 2 parts by mass. The adhesive sheet according to claim 1, wherein the storage modulus at 23 ° C after the active energy ray is applied to the adhesive layer is relative to the application of the active energy ray to the adhesive layer The ratio of storage modulus at 23 ° C is 1.1 to 2.5. The adhesive sheet according to claim 1, wherein the storage modulus at 85 ° C after the active energy ray is applied to the adhesive layer is relative to the application of the active energy ray to the adhesive layer. The ratio of storage modulus at 85 ° C is 1.1 to 3.5. The adhesive sheet according to claim 1, wherein the adhesive sheet has two release sheets, and the adhesive layer is sandwiched by the release sheet so as to be in contact with the peeling surface of the two release sheets. . A laminated body comprising two rigid plates and an adhesive layer for bonding the two rigid plates to each other, wherein the adhesive layer is the first item of the patent application scope and the sixth item of the patent application scope The adhesive layer of the adhesive sheet according to any one of the preceding claims is cured by irradiating an active energy ray. The laminated body according to claim 7, wherein at least one of the hard plates has irregularities on a surface on the side of the adhesive layer. The laminated body according to claim 8, wherein the unevenness is due to irregularities of the printed layer. The laminated body according to claim 7, wherein at least one of the hard plates comprises a polarizing plate. The laminated body according to claim 7, wherein one of the two rigid plates is a display module or a part thereof, and the other two of the two hard plates have a surface on the side of the adhesive layer. Frame-shaped bump protection board. The laminated body according to claim 7, wherein the adhesive layer has a total light transmittance of 80% or more.