TW201502233A - Adhesive sheet and laminate - Google Patents

Abstract

To provide an adhesive sheet and a laminate excellent in step difference-following property, moisture/heating whitening resistance, durability and blister resistance. An adhesive sheet 1 having an adhesive layer 11 with a thickness of 50-400 <mu>m made by thermal crosslinking of an adhesive composition, the adhesive layer 11 comprising (meth)acrylate ester copolymer (A) with a weight average molecular weight of 200,000 to 900,000 and containing, as the monomer units constituting the polymer, 5-20 mass% of carboxyl-containing monomer or 15-30 mass% of hydroxyl-containing monomer, active energy ray curable ingredient (B) and crosslinker (C), wherein the content of an active energy ray curable ingredient (B), relative to 100 parts by mass of (meth)acrylate ester copolymer (A), is 10-50 parts by mass.

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 elements, light emitting diodes (LED elements), and organic electroplated luminescent (organic EL) elements.

In such a display, generally, a protective panel is formed 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 carried out, when it 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.

In addition, as the above-mentioned protective panel, a glass plate is generally used. However, there is a case where a plastic plate is used in accordance with requirements such as thin film formation and weight reduction in recent years. In a high temperature environment, there is a case where gas (degiation) occurs from the plastic plate. In the case of using such a plastic plate, bubbles may be generated or floated or peeled off (bubble) between the plastic plate and the adhesive layer due to the above degassing.

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

In order to achieve the above object, first, the present invention provides a bonding And a sheet having a weight average molecular weight of 200,000 to 900,000 as a monomer unit constituting the polymer, containing 5 to 20% by mass of a monomer having a carboxyl group or 15 to 30% by mass of a hydroxyl group. The monomer (meth) acrylate copolymer (A), the active energy ray-curable component (B), and the bridging agent (C), and the content of the active energy ray-curable component (B), relative to the above (A) 100 parts by mass of the acrylate copolymer (A), which is composed of 10 parts by mass to 50 parts by mass of the adhesive composition, and an adhesive layer having a thickness of 50 μm to 400 μm (Invention 1).

In the above invention (Invention 1), the adhesive layer obtained by thermally bridging the adhesive composition containing a (meth) acrylate copolymer having a small weight average molecular weight and containing a predetermined hydroxyl group or a carboxyl group is obtained. It is excellent in followability and moisture and whitening resistance, and also has excellent durability. Further, the adhesive composition contains a large amount of active energy ray-curable components, and the adhesive layer is cured by irradiation with an active energy ray, and the thus-cured adhesive layer is excellent in durability and blister resistance.

In the above invention (Invention 1), the content of the bridging agent (C) in the adhesive composition is preferably 0.01 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A). 5 parts by mass (Invention 2).

In the above invention (Invention 1, Invention 2), 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 10 (Invention 3).

In the above invention (Invention 1 to Invention 3), 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 storage modulus is preferably 1.1 to 10 ( Invention 4).

In the above invention (Invention 1 to Invention 4), 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 5) ).

Secondly, the present invention provides a laminated body comprising: two rigid plates and an adhesive layer sandwiched by the two rigid plates, wherein the adhesive layer is applied to the adhesive sheet (Invention 1~) The adhesive layer of the invention 5) is cured by irradiation with an active energy ray (Invention 6).

In the above invention (Invention 6), at least one of the hard plates preferably has irregularities on the surface on the side of the adhesive layer (Invention 7).

In the above invention (Invention 7), it is preferable that the unevenness is due to the presence or absence of the printed layer (Invention 8).

In the above invention (Invention 6 to Invention 8), at least one of the hard plates preferably includes a polarizing plate (Invention 9).

In the above invention (Invention 6 to Invention 9), at least one of the hard plates preferably includes a plastic plate (Invention 10).

In the above invention (Invention 6 to Invention 8), one of the two hard plates is preferably a display module or a part thereof, and the other two of the hard plates are preferably on the side of the adhesive layer side. Protective plate with frame-like irregularities (Invention 11).

In the above invention (Invention 6 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 invention has excellent concave and convex followability After the active energy ray irradiation, it is also excellent in moist heat whitening resistance, durability, and blister resistance. 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 also excellent in moist heat whitening resistance, durability, and blister resistance.

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 by the two release sheets 12a and 12b so as to be in contact with the peeling faces of the two release sheets 12a and 12b. The adhesive layer 11 of 12b is formed. 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 pressure-sensitive adhesive layer 11 contains a monomer having a weight average molecular weight of 200,000 to 900,000 as a monomer unit constituting the polymer, and contains 5 to 20% by mass of a monomer having a carboxyl group (carboxyl group-containing monomer) or Adhesion of (meth)acrylate copolymer (A), active energy ray-curable component (B) and bridging agent (C) of a monomer having a hydroxyl group (hydroxyl-containing monomer) of 15% by mass to 30% by mass Composition (hereinafter referred to as "adhesiveness" The case of composition P". An active energy ray-curable adhesive layer composed of a thermal bridge. 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 polymerized and cured when the adhesive layer 11 is irradiated with an active energy ray when the adhesive sheet 1 is used (when the adherend is bonded).

(1) (meth) acrylate copolymer (A)

The (meth) acrylate copolymer (A) is a binder main component in the adhesive composition P. The (meth) acrylate copolymer (A) contains, as a monomer unit constituting the polymer, 5% by mass to 20% by mass of a carboxyl group-containing monomer, or 15% by mass to 30% by mass of a hydroxyl group-containing monomer. . When the content of the carboxyl group-containing monomer or the hydroxyl group-containing monomer is in 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. Durability. Further, the adhesive layer 11 obtained from the adhesive composition P containing the carboxyl group-containing monomer or the hydroxyl group-containing monomer in the above range of the (meth) acrylate copolymer (A) is After the adhesive layer 11 is cured, after performing high-temperature and high-humidity conditions (for example, under conditions of 85 ° C and 85% RH for 240 hours), whitening at the time of returning to normal temperature and normal humidity is suppressed, that is, excellent resistance to moisture and heat whitening. . When the (meth) acrylate copolymer (A) contains a carboxyl group-containing monomer or a hydroxyl group-containing monomer in the above amount as a monomer unit, a predetermined amount of a carboxyl group or a hydroxyl group remains in the obtained binder. The carboxyl group and the hydroxyl group are hydrophilic functional groups, and if such hydrophilic functional groups are quantified It is present in the adhesive. It is presumed that even if the adhesive is placed under high temperature and high humidity conditions, the moisture immersed in the adhesive under the high temperature and high humidity conditions is easy to remove from the adhesive when it returns to normal temperature and humidity. In the middle, the whitening of the adhesive is suppressed.

In the (meth) acrylate copolymer (A), if the content of the carboxyl group-containing monomer is less than 5% by mass or the content of the hydroxyl group-containing monomer is less than 15% by mass as the monomer unit, the adhesive layer 11 In particular, the resistance to moist heat whitening will be reduced. 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 coatability of the adhesive composition P deteriorates.

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

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 them, (meth)acrylic acid is preferred from the viewpoints of reactivity of the carboxyl group in the obtained (meth)acrylate polymer (A) with the bridging agent (B) and copolymerizability with other monomers. For acrylic acid. These may be used alone or in combination of two or more.

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

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) ) stearyl acrylate 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 a methyl (meth) acrylate or a n-butyl (meth) acrylate is particularly preferable. Ester and 2-ethylhexyl (meth)acrylate. Further, these may be used alone or in combination of two or more.

The (meth) acrylate copolymer (A) is preferably a (meth)acrylic acid alkyl ester having 50 to 30% by mass or more of an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer, and particularly preferably It is contained in an amount of 60% by mass or more, and more preferably 70% by mass or more. Further, the upper limit of the content of the alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group is preferably a monomer other than the carboxyl group-containing monomer. And the remainder other than the hydroxyl-containing monomer.

The (meth) acrylate copolymer (A) may contain other monomers as a monomer unit constituting the polymer, as needed. As the other monomer, it is preferred that the monomer having a reactive functional group is not contained in order not to interfere with the reaction of the carboxyl group-containing monomer or the hydroxyl group-containing monomer. Examples of such a monomer include (meth)acrylic acid alkoxyalkyl esters such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; (methyl) An aliphatic ring-containing (meth) acrylate such as cyclohexyl acrylate; a non-branching acrylamide such as acrylamide or methacrylamide; and N,N-dimethylaminoethyl (meth)acrylate (meth)acrylate having a non-branching tertiary amino group such as N,N-dimethylaminopropyl (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. The weight average molecular weight in the present specification is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

When the weight average molecular weight of the main component (meth) acrylate copolymer (A) of the adhesive composition P is small as described above, the adhesive layer 11 obtained by thermally bridging the adhesive composition P is bonded. , with excellent bump followability. When the weight average molecular weight of the (meth) acrylate copolymer (A) exceeds 900,000, the unevenness followability is lowered. 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 the active energy ray irradiation is lowered. . In view of the above, the weight average molecular weight of the (meth) acrylate copolymer (A) is particularly preferably from 300,000 to 500,000, from the viewpoint of blister resistance, from the viewpoint of blister resistance. The weight average molecular weight of the (meth) acrylate copolymer (A) is particularly preferably from 500,000 to 700,000.

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 layer P which is formed by the active energy ray-curable component (B) 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, an oligomer, or a polymer. One may also be a mixture thereof. 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 Propylene oxiranyl ethyl) isocyanate, allylation a bifunctional type such as cyclohexyl di(meth)acrylate; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylic acid Ester, pentaerythritol tri(meth) acrylate, propylene oxide modified trimethylolpropane tri(meth) acrylate, tris(propylene decyloxyethyl) isocyanate, ε-caprolactone modified tri-( a trifunctional type such as 2-(meth)acryloxyethyl)isocyanate; a tetrafunctional type such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; and propionic acid-modified dipentaerythritol A 5-functional type such as penta (meth) acrylate; a bifunctional type such as dipentaerythritol hexa(meth) acrylate or caprolactone-modified 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 obtained, for example, by reacting (meth)acrylic acid on an oxirane ring of a bisphenol type epoxy resin and a novolak type epoxy resin, and esterifying it. Further, it is also possible to use the epoxy acrylate oligomer by using a dibasic carboxylic anhydride. The resulting carboxy-modified epoxy acrylate oligomer is partially modified. 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 of two or more.

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 can be used alone or in combination More than one kind.

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 Acrylamides; monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, (meth)acrylic acid Monoalkylaminoalkyl (meth)acrylate such as monoethylaminopropyl ester; ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid or citraconic acid Wait. 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 300,000.

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 10 parts by mass to 50 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A), and is preferably 15 parts by mass to 45 parts by mass, particularly preferably 25 parts by mass to 40 parts by mass. When the content of the active energy ray-curable component (B) is 10 parts by mass or more, the adhesive layer 11 after the active energy ray irradiation improves the cohesive force, and the bubble can be suppressed even if the plastic plate is degassed in a high-temperature environment. Or the occurrence of floating and peeling is excellent in blister resistance. In other words, when the content of the active energy ray-curable component (B) is less than 10 parts by mass, excellent blister 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 smoothly peel off 12a and 12b, and the adhesive layer 11 may be damaged when the release sheets 12a and 12b are peeled off. Further, since the adhesive layer 11 after the active energy ray irradiation has an adhesive force (for a glass substrate) of 10 N/25 mm or more, the bonding state between the hard plates can be firmly maintained.

(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, after the active energy ray is irradiated, the adhesive may also be imparted with durability.

The bridging agent (C) may be a bridging agent which is reactive with a reactive functional group (carboxyl group or a hydroxyl group) which the (meth)acrylate copolymer (A) has, and examples thereof include an isocyanate bridging agent. , epoxy bridging agent, amine bridging agent, melamine bridging agent, aziridine bridging agent, anthraquinone bridging agent, aldehyde bridging agent, dysentery 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 alone or in combination of two or more.

When the (meth) acrylate copolymer (A) contains a carboxyl group-containing monomer, it is preferred to use at least one selected from the group consisting of an epoxy bridging agent having excellent reactivity with a carboxyl group and an isocyanate bridging agent as a bridging agent (C). In particular, it is preferred to use an epoxy-based bridging agent. When the (meth) acrylate copolymer (A) contains a hydroxyl group-containing monomer, it is preferred to use an isocyanate bridging agent which is excellent in 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 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; aliphatic polyisocyanates such as hexamethylene diisocyanate; and isophorone; An alicyclic polyisocyanate such as a diisocyanate or a hydrogenated diphenylmethane diisocyanate; and a biuret or isocyanate; and further examples thereof include ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and hydrazine. Sesame oil, etc. As an additive object with a reactant containing a low molecular weight active hydrogen compound.

The content of the bridging agent (C) in the adhesive composition P is preferably 0.01 parts by mass to 5 parts by mass, particularly preferably 0.05 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer (A). 1 part by mass. When the content of the bridging agent (C) is 0.01 parts 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 5 parts by mass, the degree of bridging is excessive, and the unevenness of the obtained adhesive may be lowered. Further, the carboxyl group or the hydroxyl group of the (meth) acrylate copolymer (A) is largely reacted with the bridging agent (C), and the amount of the carboxyl group or the hydroxyl group remaining in the binder is small, and the wet heat whitening resistance may be lowered. In view of the above, 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 the durability, and the bridging agent (C) is considered from the viewpoint of optimizing the blister resistance. The content is preferably from 0.3 part by mass to 1 part by mass.

(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) as described above, the active energy ray-curable component (B) can be effectively cured, and the polymerization curing time and the irradiation amount 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, 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-morphin-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, diphenyl Ketone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylindole, 2-ethylanthracene, 2-tert-butyl Base, 2-aminoindole, 2-methyl ketoxime, 2-ethyl ketoxime, 2-chlorosultone, 2,4-dimethyl ketoxime, 2,4-diethyl Kesone ketone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo [2-hydroxy-2-methyl-1[4-(1- Methylvinyl) phenyl]propanone], 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 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, as needed. Stabilizer, flame retardant, filler, refractive index modifier, etc.

In particular, from the viewpoint of improving durability, it is preferable to add a decane coupling agent as an additive to the adhesive composition P. The oxime coupling agent is preferably an organic ruthenium compound having at least one alkoxycarbenyl group in the molecule, and is preferably compatible with the (meth) acrylate copolymer (A). Moreover, when the adhesive sheet 1 is used for optical use, it is preferable that it is a light-permeable decane coupling agent.

Examples of the above decane coupling agent include vinyltrimethoxydecane, vinyltriethoxydecane, and methacryloxypropyltrimethoxy. An epoxy group having a polymerizable unsaturated group-containing fluorene compound such as decane or the like, 3-glycidoxytrimethoxydecane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, or the like A fluorene-containing hydrazine compound, 3-aminopropyl group, such as an anthracene compound, 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, 3-mercaptopropylmethyldimethoxydecane, etc. The content of trimethoxydecane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, etc. Aminoguanidine compound, 3-chloropropyltrimethoxydecane, 3-isocyanatepropyltriethoxydecane, or at least one of these and methyltriethoxydecane, ethyltriethoxydecane, A A condensate of an alkyl group-containing hydrazine compound such as a trimethoxy decane or an ethyltrimethoxy decane. 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 while adding a photopolymerization initiator (D) and/or an additive as needed to produce.

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, and methyl ethyl. A ketone or the like may be used in combination of two or more.

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-propylperoxy. 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), the active energy ray-curable component (B), the bridging agent (C), and, if necessary, are added to the solution of the (meth) acrylate copolymer (A). The photopolymerization initiator (D) and the additive are thoroughly mixed to obtain a tackifying 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. In addition, the heating It can also be used 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. After the heat treatment, a ripening period of about 1 to 2 weeks may be retained at normal temperature (for example, 23 ° C, 50% RH) as needed. In the case where the ripening period is required, after the ripening period, and when the ripening period is not required, the adhesive layer is formed after the heat treatment is completed.

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, a vinyl chloride copolymer film, and a poly Ethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, vinyl acetate film, ionomer resin film, ethylene-(A) Acrylic copolymer film, ethylene-(meth)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, and 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. In addition, at this stage, the active energy ray is not illuminated.

As another 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 the one release sheet 12a, and the adhesive composition P is thermally bridged to form a coating layer. A release sheet 12a with a coating layer was obtained. Further, 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 a coating layer. Release sheet 12b . Thereafter, the release sheet 12a with the coating layer attached thereto and the release sheet 12b with the coating layer attached thereto 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 laminated coating layer directly becomes the adhesive layer 11. Thereby, the above-mentioned adhesive sheet 1 is obtained. According to this manufacturing example, the adhesive layer 11 can be stably manufactured in a thick case.

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 modulus/active energy ray irradiation is preferably 1.1 to 10, particularly preferably 1.2 to 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 is increased, and the cured adhesive layer 11 is excellent in durability and unevenness followability. Further, from the above viewpoints, the ratio of the storage modulus is particularly preferably from 3 to 7 from the viewpoint of blister resistance.

Further, the ratio of the storage modulus at 85 ° 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) The storage modulus after the line irradiation/the storage modulus before the irradiation of the active energy ray is preferably 1.1 to 10, particularly preferably 1.3 to 7. Further, from the above viewpoint, the above energy storage is considered from the viewpoint of blister resistance. The ratio of the modulus is particularly preferably from 3 to 7.

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.

If 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 or 80 ° C exceeds 10, the adhesive strength of the cured adhesive layer 11 is lowered, and sufficient durability may not be obtained.

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 2 MPa, particularly preferably 0.05 MPa to 1 MPa, and more preferably 0.1 MPa to 0.6 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 0.5 MPa, particularly preferably 0.02 MPa to 0.2 MPa, and more preferably 0.03 MPa to 0.1 MPa. The adhesive layer 11 after the active energy ray irradiation is excellent in durability and blister resistance 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 concave portion It is also difficult to form voids or bubbles between the convex and adhesive layers 11, and the adhesive layer 11 can 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, durability, and blister resistance.

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 rigid plate 21 and the second hard plate 22 are interposed therebetween. The adhesive layer 11 is formed. 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 presence or absence of 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. Products, etc. In the adhesive layer 11 of the present embodiment, since the blister resistance is excellent, 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, flawless glass, quartz glass, soda lime glass, barium glass, aluminosilicate glass, lead glass, borosilicate glass, and bismuth boron bismuth. Acid crystal glass, etc. 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, on one or both sides of the glass plate and the plastic plate, various functional layers (a transparent conductive film, a metal layer, a ceria layer, a hard coat layer, an anti-glare layer, etc.) may be formed, or a metal wiring may be formed. There may be an optical component laminate.

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, optical member, or 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 plastic 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 printing layer 3 is not particularly limited, and printing is used. Known materials 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 particularly 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 of 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, wet heat whitening resistance, and blister 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 adhesion from the adhesive sheet 1 On the adhesive layer 11, the other release sheet 12b (or 12a) is peeled off, and the adhesive layer 11 from which the adhesive sheet 1 is exposed is bonded to the second hard sheet 22 (or the first hard sheet 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 active energy ray irradiation 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. Further, at least one of the first hard plate 21 and the second hard plate 22 may include a plastic plate, and the adhesive layer 11 that is irradiated with the active energy ray is blister-resistant even if the plastic plate is degassed under high temperature conditions. The properties are also excellent, so the occurrence of bubbles or floating and peeling is suppressed.

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 (%) after the wet heat condition of the laminate (the value measured based on JIS K7136:2000, the same applies hereinafter) can be obtained by subtracting the value of the haze value (%) before the moist heat condition (after the wet heat condition) The haze value is increased) and 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. Further, the total light transmittance of the adhesive layer 11 is generally hardly changed 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 peeling 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 second hard plate 22 may have irregularities on the side of the adhesive layer 11.

[Examples]

Hereinafter, the present invention will be further described by way of examples and the like. It is to be understood that the scope of the invention is not limited by the embodiments and the like.

[Example 1]

1. Modulation 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). The molecular weight of the (meth) acrylate copolymer (A) was measured by the method described later, and as a result, the weight average molecular weight was 600,000.

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 25 parts by mass of diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK ester A-400"); as an isocyanate bridging agent (C), trimethylolpropane modified methyl phenyl diisocyanate (Japanese polyurethane) Industrial Co., Ltd., product name "CORONATE L", 0.23 parts by mass; as a decane coupling agent, 3-glycidoxytrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") 0.2 mass In the photopolymerization initiator (D), 0.5 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name "IRUGACURE 184", manufactured by BASF Corporation) was mixed, and the mixture was sufficiently stirred to pass methyl ethyl group. The ketone was diluted to obtain a coating solution of the adhesive composition having a solid concentration of 33% by mass.

Here, the matching of the 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 tris-(2-(methyl) propylene oxiranyl ethyl) isocyanate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "A-9300-1CL")

[Bridge agent]

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

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

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 company name, "SP-PET752150" was applied by a knife coater to a thickness of 100 μm after drying, and then heat-treated at 100 ° C for 4 minutes to form a coating layer. 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" was applied by a knife coater to a thickness of 100 μm after drying, and then heat-treated at 100 ° C for 4 minutes to form a coating layer.

Next, the coating layer-attached heavy-peelable release sheet obtained above was bonded to the above-mentioned obtained light-peelable release sheet with a coating layer, and the coating layers on both sides were brought into contact with each other at 23 ° C and 50% RH. Under the conditions of aging for 7 days, an adhesive sheet formed of a structure of a heavy release type release sheet/adhesive layer (thickness: 200 μm)/light release type release sheet was produced. In addition, the thickness of the adhesive layer is a value measured based on JIS K7130 using a constant pressure thickness gauge (trade name "PG-02", manufactured by TECHLOCK Co., Ltd.).

[Examples 2 to 4, 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 the bridging agent (C), the amount of the collocation, the amount of the photopolymerization initiator (D), the amount of the hydrazine coupling agent, and the thickness of the adhesive layer were changed in accordance with Table 1, and Example 1 The same operation was carried out to manufacture a bonding sheet.

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 (height: 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 (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 described above was irradiated with ultraviolet rays under the following conditions by using an ultraviolet irradiation device (trade name "EYE GRANTAGEECS-401GX", manufactured by EYE GRAPHIC Co., Ltd.), and the adhesive layer was cured to obtain ultraviolet rays. sample. 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/cm2

‧ Illuminance: 200mW/cm2

In the above measurement results, the storage modulus after ultraviolet irradiation at 23 ° C and 85 ° C was calculated, respectively, with respect to the storage modulus before ultraviolet irradiation. Ratio (storage modulus after ultraviolet irradiation / storage modulus before ultraviolet irradiation). These measurement results and calculation results are shown in Table 2.

[Test Example 2] (Processability Evaluation)

The light release type release sheet was peeled off from the adhesive sheet obtained in the example or the comparative example, and the peeling state of the light release type release sheet was evaluated as workability. The evaluation of the smooth peeling of the light release-type release sheet from the adhesive layer was performed (O), and the evaluation of the damage of the adhesive layer when the light-peelable release sheet was peeled off was evaluated as poor workability (×). The results are shown in Table 2.

[Test Example 3] (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 the glass of one side was passed, and ultraviolet rays were irradiated under the ultraviolet irradiation conditions of Test Example 1. , 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. After that, it was returned 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 (manufactured by Nippon Denshoku Industries Co., Ltd., trade name "NDH2000"). %). 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. The evaluation of the haze value after the wet heat condition was less than 1.0 point was evaluated as good wet heat and whitening resistance (○), and the haze value after the wet heat condition was increased by more than 1.0 point and less than 5.0 points, and the evaluation was such that the wet heat whitening resistance was within an appropriate value (Δ). Haze value rises above 5.0 after hot and humid conditions The evaluation of the point was poor resistance to moist heat and whitening (×). The results are shown in Table 2.

[Test Example 4] (concavity tracking ‧ 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 produce unevenness due to printing ( The height of the concavities and convexities: 8 μm and 15 μm) are attached with a concave-convex 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 release type 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 glass plate with the unevenness.

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

(b) Concavity follow-up (initial) evaluation

The obtained evaluation sample was pressurized at 0.5 MPa and 50 ° C for 30 minutes using 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 result will be finished The evaluation of all the bubbles was ◎, the evaluation of almost no bubbles was ○, and the evaluation of bubbles was ×. (Initial evaluation of bump followability). 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). As a result, the evaluation of the absence of bubbles was ◎, the evaluation of almost no bubbles was ○, and the evaluation of bubbles was ×. (Evaluation (concavity and follow-up after durability) evaluation). The results are shown in Table 2.

[Test Example 5] (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.

[Test Example 6] (evaluation of blister resistance)

By sputtering, a transparent conductive film made of indium tin oxide (ITO) and a polyethylene terephthalate film (ITO film, manufactured by Oike Co., Ltd.) having a thickness of 125 μm were prepared.

The adhesive layer of the adhesive sheet obtained in the examples or the comparative examples was a transparent conductive film of the above ITO film and a polycarbonate plate having a thickness of 1 mm (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "UPIRON‧ SHEET MR58". In the case of the polycarbonate sheet, ultraviolet rays were irradiated under the ultraviolet irradiation conditions of Test Example 1 to obtain a laminate.

The obtained laminate was subjected to 50 ° C and 0.5 MPa. After autoclaving for 30 minutes, it was allowed to stand for 15 hours. Next, it was stored under the endurance conditions of 85 ° C and 85% RH for 72 hours. After that, it was confirmed with the naked eye whether or not there was air bubbles on the adhesive layer or floated and peeled off. As a result, the evaluation was as follows: no bubbles, no floating, and peeling were observed, ◎, almost no bubbles or floating, and evaluation of peeling was ○, bubbles were generated or floated, and peeling was evaluated as ×. (Evaluation of blister resistance). The results are shown in Table 2.

As is clear from Table 2, the adhesive sheet obtained in the examples was excellent in workability. Further, the adhesive layer obtained in the examples is excellent in unevenness after ultraviolet irradiation, and is excellent in wet heat whitening resistance, durability, and blister resistance after ultraviolet irradiation.

[Industrial Availability]

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

1‧‧‧bonding piece

11‧‧‧Adhesive layer

12a, 12b‧‧‧ peeling film

Claims (12)

An adhesive sheet having a thickness of 50 μm to 400 μm formed by a thermal bridge of an adhesive composition, wherein the adhesive layer contains a weight average molecular weight of 200,000 to 900,000 as a constituent polymer. The monomer unit contains 5 to 20% by mass of a monomer having a carboxyl group or 15 to 30% by mass of a monomer having a hydroxyl group (meth)acrylate copolymer (A) and an active energy ray-curable component (B). And the bridging agent (C), and the content of the active energy ray-curable component (B) is 10 parts by mass to 50 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A). 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 0.01 parts by mass to 5 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 10. 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 10. 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 characterized in that it has two hard plates and is covered by the above two The adhesive layer sandwiched by the sheet hard plate, wherein the adhesive layer of the adhesive sheet according to any one of claims 1 to 5 is cured by irradiation of an active energy ray. The laminated body according to claim 6, 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 Item 7, wherein the unevenness is due to irregularities of the printed layer. The laminated body according to claim 6, wherein at least one of the hard plates comprises a polarizing plate. The laminated body according to claim 6, wherein at least one of the hard plates comprises a plastic plate. The laminated body according to claim 6, wherein one of the two rigid plates is a display module or a part thereof, and the other of the two hard plates has a surface on the side of the adhesive layer. Frame-shaped bump protection board. The laminated body according to claim 6, wherein the adhesive layer has a total light transmittance of 80% or more.