JP5547869B2 - Blister resistant adhesive sheet - Google Patents

Description

  The present invention relates to a blister-resistant adhesive sheet. Specifically, the present invention relates to a blister-resistant pressure-sensitive adhesive sheet that prevents blisters such as blisters and floats when stuck on the surface of various plastic molded products.

Conventionally, pressure-sensitive adhesive sheets coated with a pressure-sensitive adhesive (pressure-sensitive adhesive) on a substrate have been widely used in many fields due to the simplicity of being able to be easily attached to an adherend by pressing. In recent years, plastic molded products have been frequently used due to demands for weight reduction of products. Accordingly, the use of pressure-sensitive adhesive sheets for attaching to plastic molded products is increasing. Examples of the plastic molded article include those obtained by molding a resin such as polycarbonate, polymethyl methacrylate, polystyrene, ABS, and the like.
When a pressure-sensitive adhesive sheet (for example, pressure-sensitive adhesive label) using a base material having a gas barrier property is attached to the surface of these plastic molded products, gas is generated from the plastic molded product, and the pressure-sensitive adhesive sheet and the plastic molded product In some cases, bubbles are formed between them and blisters or floats, that is, blisters are generated. When such blisters are generated, the appearance of the molded product is impaired, and the decorative function as an adhesive sheet is significantly reduced.
Conventionally, as an adhesive composition, for example, Patent Document 1 includes a copolymer obtained by radical polymerization of a (meth) acrylic acid ester, a copolymerizable carboxyl group-containing compound, and a tertiary amine having a vinyl group. An acrylic pressure-sensitive adhesive composition is disclosed.
Patent Document 2 discloses an aziridine-based copolymer consisting of an acrylic ester having an alkyl group having 4 to 12 carbon atoms and 0.1 to 10% by weight of a polar monomer such as acrylic acid or 2-hydroxyethyl acrylate. A blister-resistant pressure-sensitive adhesive sheet using a pressure-sensitive adhesive containing a crosslinking agent has been proposed, but it is not sufficient as a blister-resistant pressure-sensitive adhesive sheet.
Patent Document 3 discloses a pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive component and a curable component that is an acrylic monomer or oligomer as a component that forms a pressure-sensitive adhesive layer, but the curable component reduces the cohesive strength of the pressure-sensitive adhesive layer. If the adhesive layer is not compatible with the adhesive component, the adhesive layer may be whitened.
Further, in Patent Document 4, a resin composition (1) having a specific molecular weight obtained by copolymerizing a (meth) acrylic acid alkyl ester having 1 to 12 carbon atoms and a carboxyl group-containing unsaturated monomer, and 1 to 1 carbon atoms. Specific Tg and specific value obtained by copolymerization of one or more monomers selected from 20 methacrylic acid alkyl esters or methacrylic acid cycloalkyl alkyl esters, benzyl methacrylate or styrene with amino group-containing unsaturated monomers An adhesive composition containing a resin composition having a molecular weight of 1 is disclosed.
In Patent Document 5, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms as a main component, a styrenic monomer, a carboxyl group-containing unsaturated monomer, and an amino group-containing unsaturated monomer are used. A blister-resistant pressure-sensitive adhesive composition obtained by blending a copolymer having a specific molecular weight obtained by copolymerization with a crosslinking agent having a glycidyl group is disclosed, but the blister resistance is insufficient.
Patent Document 6 discloses a resin composition having a molecular weight of 1,500,000 or more and a weight average molecular weight / number average molecular weight of 4.0 or less polymerized in acetone, but the blister resistance is insufficient.

Japanese Patent Publication No. 7-98926 JP-A-8-3521 Japanese Patent No. 3618192 Japanese Patent No. 3516035 JP 2001-335766 A JP 2001-354745 A

  The present invention provides an excellent blister-resistant pressure-sensitive adhesive sheet that prevents blisters from occurring even when time elapses when pasted on the surface of various plastic molded articles under such a background. Is an issue.

  As a result of intensive studies, the present inventors have polymerized a monomer mixture containing a copolymerizable monomer having (meth) acrylic acid ester as a main component and a functional group in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet. An active energy ray-curable (meth) acrylic acid ester copolymer obtained by reacting a (meth) acrylic acid ester copolymer with an unsaturated group-containing compound having a substituent that reacts with the same functional group. It has been found that the above-mentioned problems can be solved by using a pressure-sensitive adhesive obtained by irradiating active energy rays to the pressure-sensitive adhesive composition, and the present invention has been completed.

That is, the present invention includes the following:
(1) In a pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer, the base material is a base material to which a metal vapor-deposited film is applied, and a vapor-deposited surface of the metal vapor-deposited film is bonded to the pressure-sensitive adhesive layer, The pressure-sensitive adhesive layer is mainly composed of a (meth) acrylic acid ester (a) having an alkyl group having 1 to 18 carbon atoms, and a copolymerizable monomer (b) having a functional group is 0.5 to (Meth) acrylic acid ester copolymer having a weight average molecular weight of 300,000 to 1,200,000 obtained by polymerizing a monomer mixture containing 20% by mass, and an unsaturated group-containing compound having a substituent that reacts with the same functional group (c A blister-resistant pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive obtained by irradiating a pressure-sensitive adhesive composition containing an active energy ray-curable (meth) acrylic acid ester copolymer with a reactive energy beam,
(2) The blister-resistant adhesive sheet according to (1), wherein the copolymer is a solution polymerized,
(3) The blister-resistant adhesive sheet according to (1) or (2), wherein the functional group is a hydroxyl group and / or a carboxyl group,
(4) The blister-resistant pressure-sensitive adhesive sheet according to any one of (1) to (3), wherein the unsaturated group-containing compound having a substituent is (meth) acryloyloxyethyl isocyanate.
(5) The blister-resistant pressure-sensitive adhesive sheet according to any one of (1) to (4), wherein the pressure-sensitive adhesive composition further contains a crosslinking agent,
(6) the one crosslinking agent blister resistance adhesive sheet according to (5) a polyisocyanate compound and (7) the pressure-sensitive adhesive composition (1) to include a photopolymerization initiator (6) providing blister resistance adhesive sheet for the crab according.

  By using the blister-resistant pressure-sensitive adhesive sheet of the present invention, it is possible to prevent the occurrence of blisters such as blisters and floats when pasted on the surface of various plastic molded products.

Hereinafter, the present invention will be described in detail.
As a base material used for the blister-proof adhesive sheet of this invention, it does not specifically limit as a material, Various things can be used. Examples thereof include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene; polyvinyl alcohol, polyvinylidene chloride, and polycarbonate. Among these, polyesters such as polyethylene terephthalate are preferable from the viewpoint of weather resistance and strength.
The thickness of the substrate is not particularly limited, but is about 5 to 200 μm, preferably 10 to 100 μm, from the viewpoints of thin and light weight and workability.

Moreover, as a base material, the base material which has light-shielding property or light reflectivity may be sufficient, and a transparent base material may be sufficient.
In the case where the base material is made into a colored base film in consideration of light shielding properties and light reflectivity, pigments and the like corresponding to the respective colors are blended. Further, for example, a colored layer can be formed on a substrate by coating a compound containing a pigment, a binder and a solvent on the substrate. As the binder, those used for forming the colored layer can be used without particular limitation. For example, polyurethane, phenol resin, epoxy resin, urea melamine resin, polymethyl methacrylate and the like are exemplified. The solvent is appropriately selected according to the type of pigment and binder. As the pigment, a pigment corresponding to the colored layer is appropriately selected.
The thickness of the colored layer is generally about 1 to 10 μm in total thickness. As for the thickness of each colored layer produced by the printing method, about 1-2 micrometers is preferable normally. In addition, the formation method of the colored layer by a printing method can employ | adopt the method employ | adopted conventionally in formation of a colored layer, such as gravure printing, flexographic printing, and offset printing, without a restriction | limiting.

  As a method for forming the colored layer other than the above, it can be performed by a metal vapor deposition method. Since the metal vapor deposition layer contributes to reflectivity and light shielding properties, the metal vapor deposition layer is preferably prepared by a metal vapor deposition method. The layer produced by the metal vapor deposition method is advantageous in that both the reflectivity and the light shielding rate can be improved because the surface smoothness and the denseness of the layer are better than those produced by the printing method.

  As the metal vapor deposition method, a vacuum vapor deposition method, a physical sputtering method, a chemical sputtering method, or the like can be employed. Among these, the vacuum vapor deposition method is generally employed. A metal material having a high reflectance is suitably used for forming the metal vapor deposition layer. Examples of the metal material include silver, aluminum, gold, rhodium, copper, and titanium. Among these, silver and aluminum are preferable. The thickness of a metal vapor deposition layer is about 30-100 nm, Preferably it is 40-70 nm. In addition, since a metal vapor deposition film reduces gas permeability, it becomes easy to generate | occur | produce a blister or blister. Therefore, in this invention, when the base material which gave the metal vapor deposition film is used, an effect can be exhibited more.

Next, the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer in the blister-resistant pressure-sensitive adhesive sheet of the present invention will be described.
Examples of the (meth) acrylic acid ester (a) having an alkyl group having 1 to 18 carbon atoms used in the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth N-butyl acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate , Decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. Of these, butyl (meth) acrylate and methyl (meth) acrylate are more preferred.
These may be used alone or in combination of two or more.

Examples of the copolymerizable monomer (b) having a functional group used in the present invention include (meth) acrylic acid, β-carboxyethyl acrylate, itaconic acid, crotonic acid, maleic acid, fumaric acid and maleic anhydride. Monomers having a carboxyl group, such as 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, chloro-2-hydroxypropyl acrylate, diethylene glycol mono (meth) acrylate and allyl alcohol-containing monomers, Monomers containing amino groups such as aminomethyl (meth) acrylate and monomethylaminoethyl (meth) acrylate, amide group-containing monomers such as acrylamide, methylol (meth) acrylamide and methoxyethyl (meth) acrylamide, methacrylate Examples thereof include an alkoxysilane-containing monomer such as loxypropylmethoxysilane and a monomer having an acetoacetyl group such as acetoacetoxyethyl (meth) acrylate.
Among these monomers, a monomer having a carboxyl group and a hydroxyl group-containing monomer are preferable. These can be used alone or in combination.

  The copolymerizable monomer (b) having a functional group is used in an amount of 0.5 to 20% by mass, preferably 1 to 10% by mass in the monomer mixture. If it is less than 0.5% by mass, it is necessary to reduce the amount of the unsaturated group-containing compound (c) having a substituent described later, and the expression of adhesiveness due to irradiation with active energy rays becomes insufficient. . When the amount exceeds 20% by mass, the amount of the unsaturated group-containing compound (c) described later is increased, which is not preferable because the tackiness becomes too low or the solubility in a solvent is lowered. Moreover, when the usage-amount of an unsaturated group containing compound (c) is reduced, since the functional group which remains in a copolymer increases and the water resistance of an adhesive may worsen, it is unpreferable.

  The (meth) acrylic acid ester copolymer in the present invention may be copolymerized with other vinyl monomers in addition to the components (a) and (b). Examples of the other vinyl monomers include styrene and methylstyrene. And aromatic vinyl monomers such as vinyltoluene, vinyl acetate, vinyl chloride, (meth) acrylonitrile and the like. These can be used alone or in combination.

In this invention, this (meth) acrylic acid ester copolymer may be used individually by 1 type, and may be used in combination of 2 or more type.
The (meth) acrylic acid ester copolymer in the present invention can be prepared by a conventional method in the presence or absence of an inert organic solvent. Examples of the inert organic solvent include acetone, ethyl acetate, toluene and the like. Organic solvents having a hydroxyl group such as alcohols and glycols cannot be used. Examples of the polymerization initiator include azobisisobutyronitrile, benzoyl peroxide, and the like. It does not specifically limit regarding polymerization conditions, Usually, it carries out on the conditions for 2 to 30 hours at 50-90 degreeC.
The (meth) acrylic acid ester copolymer in the present invention is not particularly limited as to its copolymerization form, and may be any of random, block, and graft copolymers.
The (meth) acrylic acid ester copolymer has a weight average molecular weight of 300,000 to 1,200,000, more preferably 400,000 to 800,000. The weight average molecular weight of the copolymer can be determined by gel permeation chromatography using polystyrene as a standard sample. When the weight average molecular weight is less than 300,000, the blister resistance is lowered, and when it exceeds 1.2 million, the viscosity becomes high and the coating property is lowered. Therefore, a large amount of solvent must be used, and the productivity is lowered. This causes manufacturing problems.

Next, the unsaturated group-containing compound (c) having a substituent that reacts with a functional group will be described.
By reacting the component (c) with a functional group such as a carboxyl group or a hydroxyl group derived from the component (b) present in the side chain of the copolymer, an unsaturated group is formed in the side chain of the copolymer. The
As the component (c), unsaturated group-containing monoisocyanate compounds such as (meth) acryloyloxymethyl isocyanate, (meth) acryloyloxyethyl isocyanate, (meth) acryloyloxypropyl isocyanate, glycidyl (meth) acrylate, 3,4 -An unsaturated group-containing chain-like or alicyclic monoepoxy compound such as epoxycyclohexylmethyl (meth) acrylate.

Next, the reaction of a functional group such as a carboxyl group or a hydroxyl group derived from the component (b) present in the side chain of the copolymer with the unsaturated group-containing isocyanate compound or epoxy compound as the component (c) will be described. .
It is preferable that the amount of component (c) used is not much greater than the amount of component (b) used in the copolymer on a chemical equivalent basis. The reason is that if the amount of the component (c) used is too large, an unreacted unsaturated group-containing isocyanate compound (isocyanate group), an epoxy compound (epoxy group) or the like remains before irradiation with the active energy ray. This is because the temporal stability of the (adhesive sheet) may deteriorate. In particular, as described later, when a crosslinking agent is added for the purpose of increasing the holding power, it is preferable that the functional group remains.
If functional groups such as carboxyl groups and hydroxyl groups derived from component (b) in the copolymer remain after the reaction, the retention is increased by adding a cross-linking agent, which is an optional component described later. It is possible to improve the adhesiveness.

  When the copolymer is produced in the presence of an organic solvent (for example, in the case of solution polymerization), the component (c) can be added to the organic solvent solution of the copolymer to be reacted. When the copolymer is produced in the absence of an organic solvent (for example, in the case of bulk polymerization, etc.), usually, the copolymer is dissolved in an organic solvent to prepare an organic solvent solution therein. Component (c) can be added and reacted. The former is preferable from the viewpoint of stability during polymerization.

You may add a crosslinking agent to the adhesive composition containing the active energy ray-curable (meth) acrylic acid ester copolymer prepared as mentioned above.
As the crosslinking agent, a polyfunctional compound having reactivity with the functional group in the acrylic copolymer can be used. Examples of the polyfunctional compound used in this case include a polyisocyanate compound, a polyepoxy compound, a polyamine compound, a melamine compound, an aziridine compound, a hydrazine compound, an aldehyde compound, an oxazoline compound, a metal alkoxide compound, a metal chelate compound, a metal salt, and ammonium. One or two or more types can be appropriately selected from salts, reactive phenol resins, and the like depending on the type of functional group in the acrylic copolymer.
Of these, polyisocyanate compounds are preferred. When mix | blending such a crosslinking agent with an adhesive composition, it is preferable that the compounding quantity of a crosslinking agent shall be about 0.1-10 mass parts with respect to 100 mass parts of copolymers.

In the present invention, the blister resistance is obtained by irradiating the adhesive composition containing the active energy ray-curable (meth) acrylic acid ester copolymer obtained by the above reaction with active energy rays.
Examples of the active energy ray include ultraviolet rays, electron beams, laser beams, α rays, β rays, γ rays, and X rays, and ultraviolet rays are most preferable from the viewpoint of ease of management, versatility, and the like.
When irradiating with ultraviolet rays, a photopolymerization initiator may be added. For example, acetophenone, 2,2-diethoxybenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, Michler's ketone, benzoin, benzoin Methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyldiphenisulphide, tetramethylthiuram monosulfide, benzyldimethyl ketal, dibenzyl, diacetyl, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-ethylanthraquinone, 2 , 2-Dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2- Ruphorinopropanone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-hydroxy-2-methyl-1-phenyl-1-propanone, diethylthioxanthone, isopropylthioxanthone, Low molecular weight polymerization initiators such as 2,4,6-trimethylbenzyldiphenyl-phosphine oxide, oligomerization such as oligo {2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone} Polymerization initiators and the like. Two or more of these may be used in combination.
The amount of such photopolymerization initiator added is the active energy ray-curable (meth) acrylate copolymer that is the curable component, that is, the (meth) acrylate copolymer having a molecular weight of 300,000 to 1,200,000. The amount is preferably about 0.01 to 5 parts by mass, more preferably about 0.1 to 3 parts by mass with respect to 100 parts by mass of the reaction product of the polymer and the component (c).

  In the case of curing by electron beam irradiation, the addition of the polymerization initiator is unnecessary, but in this case, since the curing reaction is significantly inhibited by the presence of oxygen, it must be performed in an inert gas atmosphere such as nitrogen. is there. After forming the pressure-sensitive adhesive layer by applying the pressure-sensitive adhesive composition to the substrate, it is also possible to apply the release sheet described later, or after peeling the release sheet and sticking the pressure-sensitive adhesive sheet to the adherend. Also good.

Further, in the pressure-sensitive adhesive composition, a photopolymerization accelerator can be used together with the photopolymerization initiator. Examples of such a photopolymerization accelerator include 4,4′-bis (diethylamine) benzophenone, Examples thereof include ethyl N-dimethylaminobenzoate, dimethylethanolamine, glycine and the like. Such a photopolymerization initiator and photopolymerization accelerator can be added in the form of microcapsules in order to improve stability during storage.
Furthermore, as other additives as required, various additives such as UV absorbers, tackifiers, softeners (plasticizers), fillers, anti-aging agents, pigments, dyes, silane coupling agents, etc. Can be added.

Examples of the tackifier include rosin and derivatives thereof, polyterpene, terpene phenol resin, coumarone-indene resin, petroleum resin, styrene resin, and xylene resin.
Examples of the softening agent include liquid polyether, glycol ester, liquid polyterpene, liquid polyacrylate, phthalic acid ester, trimellitic acid ester, and the like.

  In order to form the pressure-sensitive adhesive layer having the curable component as a main component on the substrate, for example, a blade coater, knife coater, roll coater, reverse roll coater, bar coater, curtain coater, die slot coater, gravure coater And a device such as a lip coater can be used as appropriate. The thickness (dry film thickness) of the pressure-sensitive adhesive layer is about 10 to 50 μm, preferably about 15 to 35 μm.

In the stage before the blister resistant pressure-sensitive adhesive sheet of the present invention is adhered to the adherend, a release sheet may be adhered to the pressure-sensitive adhesive layer side.
Any known release sheet may be used. For example, a release sheet having a release agent coat layer, for example, a silicone layer formed on the bonding surface of the release sheet to the adhesive layer of the substrate may be used. Can do. Examples of the base material of the release sheet include a paper film such as glassine paper and a resin film made of polyester.

  Further, the use of the blister-resistant pressure-sensitive adhesive sheet of the present invention is not particularly limited, but it is preferably substantially transparent or translucent when light transmittance is required. Thereby, even if it sticks, for example to the display of an optical apparatus, a vehicle window, etc., visibility is not impaired.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited only to a following example.
<Evaluation method or test method>
(1) Holding power Measured according to JIS Z-0237 at 40 ° C. under a load of 9.8 N, and the number of seconds until dropping was shown.
(2) Blister resistance test After removing the release sheet from the anti-blister adhesive sheet obtained in each example and the comparative adhesive sheet, a squeegee was used on a transparent polycarbonate plate (Mitsubishi Gas Chemical Co., Ltd., Iupilon sheet NF-2000VU). Glue. After standing for 30 minutes, it was left in a 90 ° C. hot air dryer for 1 hour to observe the occurrence of blisters after heating was promoted and evaluated according to the following criteria.
○: Blister is not seen. Δ: Blister is seen partially.
X: Blister is seen over the entire surface.
[Example 1]

Under a nitrogen atmosphere, 90 parts by mass of n-butyl acrylate, 10 parts by mass of acrylic acid and azobisisobutyronitrile (polymerization initiator) 0. 25 parts by mass was reacted in ethyl acetate at 60 ° C. for 24 hours to obtain an acrylic acid ester copolymer solution (solid content concentration: 40% by mass) having a weight average molecular weight of 400,000. After adding methyl ethyl ketone to the obtained acrylic acid ester copolymer to make the solid content concentration 35% by mass, 5 parts by mass of 2-methacryloyloxyethyl isocyanate is added and reacted at 50 ° C. for 12 hours to obtain active energy rays. A curable acrylic ester copolymer solution was obtained.
1 part by mass of “Irgacure 651 (solid content: 100% by mass)” manufactured by Ciba Specialty Chemicals as a photopolymerization initiator is dissolved in 100 parts by mass of the obtained active energy ray-curable acrylic ester copolymer solution. Thus, the solid content concentration was adjusted to 30% by mass to obtain a coating agent (adhesive composition) for the adhesive layer.
A release sheet (SP-PET 3801, manufactured by Lintec Co., Ltd.), which has been subjected to release treatment with a light release silicone resin on one side of a polyethylene terephthalate (PET) film (thickness: 38 μm), and a polyethylene terephthalate (PET) film (thickness) as a base material : 50 μm), two types of films were prepared: a vapor-deposited film (Metal Me # 50, manufactured by Toray Film Processing Co., Ltd.) having an aluminum vapor-deposited treatment on one side.
The pressure-sensitive adhesive layer coating agent obtained above was applied to the release-treated surface of the light release type release sheet with a knife coater and dried at 90 ° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 15 μm. The pressure-sensitive adhesive layer was bonded to the surface of the vapor-deposited film as a base material to form a pressure-sensitive adhesive sheet.
A blister-resistant pressure-sensitive adhesive sheet was prepared by irradiating ultraviolet rays from the release sheet side of this pressure-sensitive adhesive sheet (manufactured by Lintec Corporation, using device name Adwill RAD-2000m / 8, illuminance of 310 mW / cm ² , light amount of 300 mJ / cm ² ). .

[Example 2]
A blister-resistant adhesive sheet was prepared in the same manner as in Example 1 except that 1 part by mass of a crosslinking agent comprising a polyisocyanate compound (manufactured by Toyo Ink Manufacturing Co., Ltd., BHS8515, solid content concentration 35% by mass) was added together with the photopolymerization initiator. Produced.

Example 3
A blister-resistant pressure-sensitive adhesive sheet was prepared in the same manner as in Example 2 except that the acrylic acid ester copolymer solution having a weight average molecular weight of 400,000 was obtained by using 2-hydroxyethyl acrylate instead of acrylic acid. .

Example 4
A blister-resistant adhesive in the same manner as in Example 2 except that 1 part by mass of an epoxy-based cross-linking agent (E-AX, solid content 5% by mass) was used instead of the polyisocyanate compound. A sheet was produced.

[Comparative Example 1]
A comparative pressure-sensitive adhesive sheet was prepared in the same manner as in Example 2 except that 2-methacryloyloxyethyl isocyanate and a photopolymerization initiator were not used.

[Comparative Example 2]
A comparative pressure-sensitive adhesive sheet was produced in the same manner as in Example 2 except that an acrylic ester copolymer having a weight average molecular weight of 200,000 was used.

[Comparative Example 3]
A comparative pressure-sensitive adhesive sheet was produced in the same manner as in Example 3 except that 2-methacryloyloxyethyl isocyanate and a photopolymerization initiator were not used.

[Comparative Example 4]
A comparative pressure-sensitive adhesive sheet was produced in the same manner as in Example 4 except that 2-methacryloyloxyethyl isocyanate and a photopolymerization initiator were not used.

[Comparative Example 5]
Under a nitrogen atmosphere, 90 parts by mass of n-butyl acrylate, 10 parts by mass of acrylic acid and azobisisobutyronitrile (polymerization initiator) 0. 25 parts by mass was reacted in ethyl acetate at 60 ° C. for 24 hours to obtain an acrylate copolymer solution (solid content concentration: 40% by mass) having a mass average molecular weight of 400,000. With respect to 100 parts by mass of the resulting acrylate copolymer solution, 1 part by mass of a crosslinking agent comprising a polyisocyanate compound (manufactured by Toyo Ink Manufacturing Co., Ltd., BHS8515, solid content concentration 35% by mass), and active energy ray curability Dissolve 10 parts by mass of resin (Kyoeisha Chemical Co., Ltd., light acrylate DCP-A, solid content concentration: 100% by mass) and adjust the solid content concentration to be 30% by mass to obtain a coating agent for the adhesive layer. Otherwise, a comparative pressure-sensitive adhesive sheet was prepared in the same manner as in Example 2.

  It can be used by sticking to the surface of various plastic molded articles as an excellent blister-resistant adhesive sheet that prevents the occurrence of blisters such as blistering and floating.

Claims (7)

In the pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer, the base material is a base material to which a metal vapor-deposited film is applied, and a vapor-deposited surface of the metal vapor-deposited film is bonded to the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer However, the copolymerizable monomer (b) having a (meth) acrylic acid ester (a) having an alkyl group having 1 to 18 carbon atoms as a main component and having a functional group is 0.5 to 20% by mass in the mixture. A (meth) acrylic acid ester copolymer having a weight average molecular weight of 300,000 to 1,200,000 obtained by polymerizing a monomer mixture, and an unsaturated group-containing compound (c) having a substituent that reacts with the same functional group. A blister-resistant pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive obtained by irradiating a pressure-sensitive adhesive composition containing an active energy ray-curable (meth) acrylic acid ester copolymer obtained by reaction with active energy rays.   The blister-resistant pressure-sensitive adhesive sheet according to claim 1, wherein the copolymer is a solution polymerized.   The blister-resistant adhesive sheet according to claim 1 or 2, wherein the functional group is a hydroxyl group and / or a carboxyl group.   The blister-resistant adhesive sheet according to any one of claims 1 to 3, wherein the unsaturated group-containing compound having a substituent is (meth) acryloyloxyethyl isocyanate.   The blister-resistant pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive composition further contains a crosslinking agent.   The blister-resistant adhesive sheet according to claim 5, wherein the crosslinking agent is a polyisocyanate compound.   The blister-resistant pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive composition contains a photopolymerization initiator.