JP2007051293A - Pressure-sensitive adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive sheet enabling a seasoning period to be shortened, and having a wide application range as a product matching to required properties in various kinds of applications such as the one for permanent adhesion use and the one for removal use. <P>SOLUTION: The pressure-sensitive adhesive sheet is obtained by forming a thin film comprising a compound obtained by compounding at least 1-100 pts.wt. acrylic polymer (B) having a radiation-polymerizable group on a side chain with 100 pts.wt. acrylic polymer (A) obtained by polymerizing a monomer consisting essentially of an alkyl (meth)acrylate having a 1-18C alkyl group, and crosslinking the resultant thin film by radial rays. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive sheet and a method for producing the same.

  Conventionally, a pressure-sensitive adhesive sheet is obtained by, for example, applying a mixed solution containing a crosslinking agent and an acrylic polymer having an active group for the crosslinking agent on a substrate, and then heating the mixture to heat the crosslinking agent and the acrylic polymer. It is produced by reacting a coalescence and crosslinking an acrylic polymer.

  As such a pressure-sensitive adhesive sheet, there is a sheet using a heat crosslinking agent as a crosslinking agent, but it has a disadvantage that a seasoning period is too long. On the other hand, a pressure-sensitive adhesive sheet (for example, Japanese Patent No. 2592875, Claim 5, Example) in which a polyfunctional radiation-curable monomer (photocrosslinkable compound) is used as a crosslinking agent and is radiation-crosslinked. 3) can shorten the seasoning period, but has a drawback that it is difficult to obtain high adhesion and high tack when trying to obtain high cohesion. A pressure-sensitive adhesive sheet obtained by radiation-crosslinking an acrylic polymer having a radiation-polymerizable group in the side chain is also known (Japanese Patent Laid-Open No. 49-5145), but the radiation-polymerizable group in the side chain. Depending on the reaction conditions at the time of introduction, the type of monomer used for the main chain of the acrylic polymer is limited, and it has a drawback that it is difficult to obtain desired adhesive properties. Furthermore, there is also a technique for radiation crosslinking directly from a radiation curable monomer blend without using an acrylic polymer, but the unreacted monomer remains and the performance of the resulting pressure sensitive adhesive sheet, Durability may be adversely affected, and the types of monomers that can be used as pressure-sensitive adhesives are limited, so the application range of products is also limited.

  In addition, pressure-sensitive adhesive sheets made by laminating optical components such as polarizing plates are required to have various durability such as heat resistance, moisture resistance, and whiteout resistance, and the feeling of shortening the seasoning period by conventional methods. In the pressure-sensitive adhesive sheet, it has been extremely difficult to satisfy all of these.

  It is an object of the present invention to provide a pressure-sensitive adhesive sheet that can shorten the seasoning period and can meet the required performance in various applications such as permanent bonding, re-peeling, and a wide range of application as a product. To do.

The present invention includes the following inventions.
(1) Acrylic polymer (A) obtained by polymerizing a monomer having (meth) acrylic acid alkyl ester having a C 1-18 alkyl group as a main component on a support or a release sheet 100 weight Pressure sensitive adhesive obtained by forming a thin film composed of a blend in which at least 1 to 100 parts by weight of an acrylic polymer (B) having a radiation-polymerizable group in the side chain is blended with respect to the part and radiation-crosslinking Sheet.
(2) The pressure-sensitive adhesive sheet according to (1), wherein the support is a sheet-like optical component.
(3) At least a side with respect to 100 parts by weight of an acrylic polymer (A) formed by polymerizing a monomer mainly composed of (meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms A pressure-sensitive adhesive sheet characterized by blending 1 to 100 parts by weight of an acrylic polymer (B) having a radiation-polymerizable group in a chain, forming a thin film on a support or a release sheet, and then crosslinking the radiation. Manufacturing method.

  The pressure-sensitive adhesive sheet of the present invention requires a short seasoning period and can meet the required performance for permanent bonding, re-peeling, and other various uses, and the pressure-sensitive adhesive by the production method of the present invention The sheet has a wide range of application as a product.

  In the present invention, as the (meth) acrylic acid alkyl ester used as the main component of the raw material monomer of the acrylic polymer (A), various alkyl groups constituting the ester group are alkyl groups having 1 to 18 carbon atoms. Can be used, specifically, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, Examples include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate and the like.

  In the present invention, as the monomer constituting the acrylic polymer (A), the above (meth) acrylic acid alkyl ester may be used singly or in combination of two or more, and may be further copolymerized. A monomer may be used in combination. As other copolymerizable monomers, acrylic pressure sensitive such as vinyl acetate, styrene, acrylonitrile, acrylamide, acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate, etc. Any of various types of monomers known as monomers for modifying adhesives can be used. These other monomers are preferably 50% by weight or less in the total amount with the (meth) acrylic acid alkyl ester in terms of adhesive properties.

  The acrylic polymer (A) used as the main component of the pressure-sensitive adhesive in the present invention is composed of a homopolymer or copolymer of an acrylic monomer having the (meth) acrylic acid alkyl ester as a main component. The weight average molecular weight measured by a gel permeation chromatography method (hereinafter referred to as “GPC method”) is usually 200,000 to 2,500,000, preferably 500,000 to 1,500,000. The glass transition temperature of the acrylic polymer (A) is usually −20 ° C. or lower, preferably about −30 to −60 ° C.

  The acrylic polymer having the molecular weight as described above can be prepared by using, for example, various monomers such as a solution polymerization method, an emulsion polymerization method, and a bulk polymerization method by using the above-described monomer with a polymerization catalyst such as an azo compound or a peroxide. It can be easily obtained by a legal method. The acrylic polymer (B) having a radiation-polymerizable group in the side chain used in the present invention has an acrylic polymer (b1) having a functional group-containing monomer unit and a substituent that reacts with the functional group. It is obtained by reacting the radiation polymerizable group-containing compound (b2).

  The functional group-containing monomer is a monomer having a polymerizable double bond and a functional group such as hydroxyl group, carboxyl group, amino group, substituted amino group, isocyanate group, and epoxy group in the molecule. Preferably, a hydroxyl group-containing unsaturated compound and a carboxyl group-containing unsaturated compound are used.

  As more specific examples of such functional group-containing monomers, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxy acrylate Examples include hydroxyl group-containing acrylates such as hydroxybutyl, and carboxyl group-containing compounds such as acrylic acid, methacrylic acid, and itaconic acid.

  The functional group-containing monomers may be used alone or in combination of two or more. The acrylic polymer (b1) includes a structural unit derived from the functional group-containing monomer and a structural unit derived from a (meth) acrylic acid alkyl ester monomer or a derivative thereof. As the (meth) acrylic acid alkyl ester monomer, (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms, cycloalkyl (meth) acrylate, and benzyl (meth) acrylate are used. Among these, the (meth) acrylic-acid alkylester which has the C1-C18 alkyl group similar to the raw material monomer of an acrylic polymer (A) is used more preferable.

  The acrylic polymer (b1) contains a structural unit derived from the functional group-containing monomer in an amount of usually 3 to 50% by weight, preferably 5 to 30% by weight, and (meth) acrylic acid ester The structural unit derived from the body or a derivative thereof is usually 50 to 97% by weight, preferably 70 to 95% by weight.

  The acrylic polymer (b1) is obtained by copolymerizing a functional group-containing monomer as described above with a (meth) acrylic acid alkyl ester monomer or a derivative thereof in a conventional manner. In addition to the monomer, vinyl formate, vinyl acetate, styrene and the like may be copolymerized in a small amount (for example, 10% by weight or less, preferably 5% by weight or less). By reacting the acrylic polymer (b1) having the functional group-containing monomer unit with the radiation-polymerizable group-containing compound (b2) having a substituent that reacts with the functional group, a radiation-polymerizable group is added to the side chain. An acrylic polymer (B) having

  The radiation polymerizable group-containing compound (b2) contains a substituent capable of reacting with the functional group in the acrylic polymer (b1). This substituent varies depending on the type of the functional group. For example, when the functional group is a hydroxyl group or a carboxyl group, the substituent is preferably an isocyanate group, an epoxy group, a chlorosilane group, or the like. When the functional group is an amino group or a substituted amino group, the substituent is an isocyanate group or the like. In the case where the functional group is an epoxy group, the substituent is preferably a carboxyl group. One such substituent is included in each molecule of the radiation polymerizable group-containing compound (b2).

  The radiation-polymerizable group-containing compound (b2) contains 1 to 5, preferably 1 to 2, radiation-polymerizable groups, for example, a radiation-polymerizable carbon-carbon double bond per molecule. . Specific examples of such a radiation polymerizable group-containing compound (b2) having a carbon-carbon double bond include, for example, methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, Methacryloyl isocyanate, allyl isocyanate; acryloyl monoisocyanate compound obtained by reaction of diisocyanate compound or polyisocyanate compound with 2-hydroxyethyl (meth) acrylate; diisocyanate compound or polyisocyanate compound; , An acryloyl monoisocyanate compound obtained by reacting a polyol compound with 2-hydroxyethyl (meth) acrylate; glycidyl (meth) acrylate; (meth) acrylic acid; 3-methacryloxypropyldimethyl A chlorosilane etc. are mentioned.

  The radiation-polymerizable group-containing compound (b2) is usually used at a ratio of 20 to 100 equivalents, preferably 40 to 95 equivalents per 100 equivalents of the functional group-containing monomer of the acrylic polymer (b1). The reaction of the acrylic polymer (b1) and the radiation polymerizable group-containing compound (b2) is usually performed at a temperature of room temperature to about 40 ° C. and a normal pressure for about 4 to 48 hours. This reaction is preferably performed using a catalyst such as an organotin compound (for example, dibutyltin laurate) or a substituted amine compound in a solution such as ethyl acetate.

  As a result, the functional group present in the side chain in the acrylic polymer (b1) reacts with the substituent in the radiation-polymerizable group-containing compound (b2) to produce a radiation-polymerizable group (for example, carbon-carbon dioxygen). Heavy bond) is introduced into the side chain in the acrylic polymer (b1) to obtain an acrylic polymer (B) having a radiation polymerizable group in the side chain. The reaction rate between the functional group and the substituent in this reaction is usually 70% or more, preferably 80% or more, in the acrylic polymer (B) in which the unreacted functional group has a radiation polymerizable group in the side chain. May remain.

  The weight average molecular weight measured by GPC method of the acrylic polymer (B) having a radiation polymerizable group in the side chain is usually 1,000 to 1,000,000, preferably 50,000 to 500,000. Moreover, the glass transition temperature of an acrylic polymer (B) is 20 degrees C or less normally, Preferably it is about -65-10 degreeC. Since the acrylic polymer (B) having a radiation polymerizable group in such a side chain contains a radiation polymerizable group, it is crosslinked by irradiation with radiation.

  The composition used for the production of the pressure-sensitive adhesive sheet of the present invention is based on 100 parts by weight of the acrylic polymer (A) composed of a monomer mainly composed of the (meth) acrylic acid alkyl ester. At least 1 to 100 parts by weight, preferably 5 to 50 parts by weight of the acrylic polymer (B) having a radiation polymerizable group in the side chain is contained. When the blending ratio of the acrylic polymer (B) is less than 1 part by weight, the resulting pressure-sensitive adhesive cannot obtain sufficient cross-linking, and high durability is difficult to obtain, whereas when it exceeds 100 parts by weight. Adhesive strength and tack become insufficient, and there is a possibility that the performance to be expressed by the acrylic polymer (A) as the main agent may be difficult to obtain.

  The pressure-sensitive adhesive sheet of the present invention can be obtained by forming a thin film (pressure-sensitive adhesive layer) comprising the above composition on a support or a release sheet, and irradiating it with radiation to crosslink it. . Specifically, ultraviolet rays, electron beams, etc. are used as the radiation. The amount of irradiation varies depending on the type of radiation. For example, when ultraviolet rays are used, about 40 to 400 W / cm is preferable, and when an electron beam is used, about 10 to 1000 krad is preferable. When ultraviolet rays are used as the radiation, it is preferable to blend a photopolymerization initiator (C) in the composition.

  Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, and benzoin. Examples include dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, and β-chloroanthraquinone. . The compounding quantity of a photoinitiator (C) is 0.1-10 weight part normally with respect to 100 weight part of said acrylic polymers (B), Preferably it is 0.5-5 weight part.

  Furthermore, in order to control the curing characteristics against radiation, a low-molecular-weight radiation-polymerizable compound (D) can be added to the composition. The molecular weight of the compound (D) is usually 10,000 or less, preferably about 100 to 8000, more preferably about 100 to 3000.

  Specific examples of such a radiation-polymerizable compound (D) include monofunctional acrylate monomers, polyfunctional acrylate monomers, urethane acrylate oligomers, polyester acrylate oligomers, and epoxy acrylate oligomers.

  The compounding amount of the radiation polymerizable compound (D) is usually 30 parts by weight or less, preferably 10 parts by weight or less with respect to 100 parts by weight of the acrylic polymer (A). If the amount of compound (D) is too large, sufficient adhesive strength and tack cannot be obtained. In addition, the composition includes a heat-crosslinking agent such as an organic polyvalent isocyanate compound, an organic polyvalent epoxy compound, a metal chelate compound, or an organic polyvalent imine compound in order to improve adhesion with a material to be laminated. Can also be added. In this case, a slight variation in adhesive properties is observed after radiation crosslinking, but the period of variation is substantially shorter than those of these heat crosslinking agents alone.

  Examples of the organic polyvalent isocyanate compound include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, trimers of these polyvalent isocyanate compounds, And a terminal isocyanate urethane prepolymer obtained by reacting a polyvalent isocyanate compound with a polyol compound. Specific examples of the organic polyvalent isocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylylene diisocyanate. And the reaction product of these organic polyvalent isocyanate compounds and polyhydric alcohols (for example, trimethylolpropane tris (4-methyl-3-isocyanatophenylcarbamate)).

  Specific examples of the organic polyvalent epoxy compound include bisphenol A type epoxy compound, bisphenol F type epoxy compound, 1,3-bis (N, N-diglycidylaminomethyl) benzene, 1,3-bis (N, N -Diglycidylaminomethyl) Toluene, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane and the like. Specific examples of the metal chelate compound include coordination compounds of polyvalent metals such as trisethyl acetoacetate aluminum, ethyl acetoacetate aluminum diisopropylate, and trisacetylacetonatoaluminum.

  Specific examples of the organic polyvalent imine compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylol. And methane-tri-β-aziridinylpropionate, N, N′-toluene-2,4-bis (1-aziridinecarboxamide) triethylenemelamine, and the like.

  The amount of the heat crosslinking agent is usually 5 parts by weight or less, preferably 1 part by weight or less, with respect to 100 parts by weight of the acrylic polymer (A). If the blending amount of the heat crosslinking agent is too large, the variation in physical properties after radiation crosslinking becomes large, and it becomes difficult to shorten the seasoning period. The thickness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet of the present invention is usually 1 to 100 μm, preferably 5 to 50 μm, and more preferably about 10 to 30 μm.

  In the pressure-sensitive adhesive sheet of the present invention, a support may be provided on one side of the pressure-sensitive adhesive layer. There is no restriction | limiting in particular as a support body used here, For example, other than the sheet-like plastic material used for various optical components, such as polyvinyl alcohol, a triacetyl cellulose, a polymethylmethacrylate, a polycarbonate, a polysulfone-type resin, a polynorbornene-type resin. , Polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, ethylene / vinyl acetate copolymer, polyurethane, polystyrene, polyimide and other resin films, fine paper, coated paper, laminated paper, metal foil, woven fabric, non-woven fabric, Or these laminated bodies are used. The thickness of such a support is usually 6 to 300 μm, preferably 12 to 200 μm.

  In addition, a release sheet is laminated on the opposite surface provided with the support of the pressure-sensitive adhesive sheet in order to protect the pressure-sensitive adhesive. As the release sheet, for example, a sheet material selected from the above-mentioned support and subjected to release treatment such as silicone resin is used. Furthermore, the pressure-sensitive adhesive sheet of the present invention may be in a form that does not use the above-mentioned support. In this case, the pressure-sensitive adhesive sheet is used in a shape in which both surfaces thereof are protected by the release sheet.

  In the production of the pressure-sensitive adhesive sheet of the present invention, after mixing and stirring the aforementioned pressure-sensitive adhesive composition, known coatings such as knife coaters, roll knife coaters, reverse roll coaters, gravure coaters, die coaters, etc. The desired thickness is coated on the aforementioned support or release sheet by an apparatus. When the blend is a solution, suspension or the like, volatile components such as a solvent are removed by drying to form a pressure-sensitive adhesive layer. Next, radiation is applied directly from the support (release sheet) side or from the pressure-sensitive adhesive layer side to crosslink the pressure-sensitive adhesive layer, and the release sheet or support is applied to the exposed pressure-sensitive adhesive layer side. By laminating, the pressure-sensitive adhesive sheet of the present invention is produced.

  Irradiation may be performed after laminating the support or release sheet on both sides of the pressure-sensitive adhesive layer. In this case, it is also possible to perform radiation irradiation immediately before applying the pressure-sensitive adhesive sheet to the adherend, for example, without continuously performing the coating process and the radiation irradiation process. In addition, when irradiating a radiation through a support body or a peeling sheet, the support body or peeling sheet needs to be transparent with respect to the radiation to be used.

  The adhesive force (after radiation cross-linking) of the pressure-sensitive adhesive sheet of the present invention is 100 g / 25 mm or more, preferably 300 to 3000 g / 25 mm or more, like the general-purpose pressure-sensitive adhesive sheet. If it is the adhesive force of such a range, it can apply as various general-purpose pressure sensitive adhesive sheets, such as a permanent adhesive type and a re-peeling type. In addition, the pressure-sensitive adhesive sheet of the present invention has a polarizing plate, a retardation plate, an analyzer, a coating, and the like that require stricter performance than general-purpose pressure-sensitive adhesive sheets such as heat resistance, moisture resistance, and whiteout resistance. It can also be suitably used for optical parts such as photons.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, these do not restrict | limit the scope of the present invention at all. In addition, the various physical properties and test methods in Examples and Comparative Examples are as follows.

(aging)
One day later, the adhesive strength was affixed to a glass plate with a width of 25 mm and peeled off 180 degrees one day after the preparation of pressure-sensitive adhesive sheets of Examples 1 to 6 and Comparative Examples 1 to 4 described later (one day after radiation irradiation). Measured by the method (JIS Z0237) (g / 25 mm).
After 14 days, the adhesive strength was measured on the glass plate with a width of 25 mm and peeled 180 degrees (JIS Z0237) 14 days after the creation of the pressure-sensitive adhesive sheet (14 days after irradiation) (g / 25 mm) .

The evaluation of shortening of aging was evaluated by the ratio of the adhesive strength change between the adhesive strength after 1 day and the adhesive strength after 14 days.
○: 0% to less than 15%, ×: 15% or more

(Ball tack test)
Ball tack was measured by the J. Dow method 7 days after the production of the pressure-sensitive adhesive sheets of Examples 1 to 6 and Comparative Examples 1 to 4 described later.
(Holding power)
Holding force is 7 days after creation of the pressure sensitive adhesive sheets of Examples 1 to 6 and Comparative Examples 1 to 4 described later, until 25 × 25 mm is applied to a stainless steel plate and peeled off by applying a load of 2 kg at 40 ° C. Was measured. When held for 70000 seconds, the deviation width was measured.
(Clear white)
The white spots are obtained by pasting the pressure-sensitive adhesive sheets of Examples 7 to 12 and Comparative Examples 5 to 8, which will be described later, on both surfaces of the glass so as to be in a crossed Nicol state, and after leaving it to stand at 90 ° C. for 100 hours. The light transmission was visually evaluated.
○: No light transmission, ×: Light leakage (durability test)
Durability was evaluated by visual observation of changes in appearance after pasting pressure sensitive adhesive sheets of Examples 7 to 12 and Comparative Examples 5 to 8 described later on glass and leaving them to stand at 60 ° C. and 90% Rh for 100 hours. did.
◎: No change, ○: Small foam or crack at the end, ×: Lifting off

(Examples 1-12 and Comparative Examples 1-8)
(1) Production of acrylic polymer A To a composition comprising each monomer described later, 0.33 parts by weight of azobisisobutyronitrile as a polymerization initiator and 250 parts by weight of ethyl acetate as a solvent were added, and nitrogen substitution was performed. Then, the mixture was reacted at 60 ° C. for 7 hours and then refluxed for 5 hours for polymerization. The obtained polymer solution was adjusted to have a solid content of 25% by weight.
(A1) A 25% ethyl acetate solution of a copolymer having a weight average molecular weight of 1 million (glass transition temperature: −48 ° C.) composed of 96 parts by weight of n-butyl acrylate and 4 parts by weight of acrylic acid.
(A2) A 25% ethyl acetate solution of a copolymer having a weight average molecular weight of 1.3 million (glass transition temperature: −54 ° C.) comprising 99 parts by weight of n-butyl acrylate and 1 part by weight of 2-hydroxyethyl acrylate.
(A3) A 25% ethyl acetate solution of a copolymer having a weight average molecular weight of 200,000 (glass transition temperature: −45 ° C.) composed of 90 parts by weight of n-butyl acrylate and 10 parts by weight of acrylic acid.

(2) Production of Acrylic Polymer B Having Radiation-Polymerizable Group in Side Chain An acrylic polymer solution listed in each (b1) was produced by the same operation as acrylic polymer A described above. To 100 parts by weight of the obtained 25% by weight polymer solution, 0.3 parts by weight of dibutyltin laurate as a compound listed in (b2) and a catalyst were added and reacted at room temperature and normal pressure for 24 hours.

(B1) Weight average molecular weight 200,000, glass transition temperature: -45 ° C
(B1) 25% ethyl acetate solution of the acrylic copolymer A3 (b2) 4.5 parts by weight of glycidyl methacrylate (91 equivalents per 100 equivalents of carboxyl groups in (b1))

(B2) Weight average molecular weight 300,000, Glass transition temperature: -49 ° C
(B1) 25% ethyl acetate solution of a copolymer having a weight average molecular weight of 300,000 consisting of 80 parts by weight of n-butyl acrylate and 20 parts by weight of 2-hydroxyethyl acrylate (b2) 6 parts by weight of methacryloyloxyethyl isocyanate ( (90 equivalents per 100 equivalents of hydroxyl group of (b1))

(B3) Weight average molecular weight 300,000, glass transition temperature: -39 ° C
(B1) 25% ethyl acetate solution of a copolymer having a weight average molecular weight of 300,000 consisting of 70 parts by weight of n-butyl acrylate, 20 parts by weight of 2-hydroxyethyl acrylate and 10 parts by weight of methyl methacrylate (b2) methacryloyloxy 6 parts by weight of ethyl isocyanate (90 equivalents per 100 equivalents of hydroxyl group of (b1))

(B4) Weight average molecular weight 300,000, glass transition temperature: -39 ° C
(B1) 25% ethyl acetate solution of a copolymer having a weight average molecular weight of 300,000 consisting of 70 parts by weight of n-butyl acrylate, 20 parts by weight of 2-hydroxyethyl acrylate and 10 parts by weight of methyl methacrylate (b2) 3- 8.5 parts by weight of methacryloxypropyldimethylchlorosilane (89 equivalents per 100 equivalents of hydroxyl group of (b1))

(3) Manufacture of a pressure-sensitive adhesive sheet The coating amount after drying the solution of the pressure-sensitive adhesive composition which consists of the mixing | blending of solid weight ratio shown in Table 1 to a polyethylene terephthalate film (thickness 50 micrometers) is 25 g / m < ² >. After being coated at 90 ° C. for 1 minute, it was bonded to an ultraviolet transparent release sheet (trade name SP-PET3811, manufactured by Lintec Corporation), and except for Comparative Examples 1 and 2, ultraviolet rays were applied from the release sheet side. The pressure sensitive adhesive sheets of Examples 1 to 6 and Comparative Examples 1 to 4 having a polyethylene terephthalate film on the support were obtained by irradiation (high pressure mercury lamp 120W2 lamp, irradiation distance 10 cm, line speed 5 m / min).

Separately, the application amount after drying a solution of the same pressure-sensitive adhesive composition as in Examples 1 to 6 and Comparative Examples 1 to 4 on a release sheet (product name SP-PET3811, manufactured by Lintec Corporation) is 25 g / m ^2. After coating at 90 ° C. for 1 minute, it was laminated with a polarizing plate (trade name SR-1862A, manufactured by Sumitomo Chemical Co., Ltd.) consisting of three layers of triacetyl cellulose / polyvinyl alcohol / triacetyl cellulose, and Comparative Example 5 The pressure sensitive adhesive sheets of Examples 7 to 12 and Comparative Examples 5 to 8 having a polarizing plate on the support were obtained by irradiating ultraviolet rays from the release sheet side except for No. 6 and No. 6.
The obtained pressure-sensitive adhesive sheet was evaluated for various physical properties. The results are shown in Tables 2 and 3.

  As the photopolymerization initiator, 1-hydroxycyclohexyl phenyl ketone was used. As the organic polyvalent isocyanate compound, trimethylolpropane tris (4-methyl-3-isocyanatophenylcarbamate) (trade name Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) was used. Trimethylolpropane triacrylate was used as the radiation polymerizable compound.

cf (cohesive failure): cohesive failure, NC (non creep): no deviation

Claims (3)

  On 100 parts by weight of an acrylic polymer (A) obtained by polymerizing a monomer mainly composed of (meth) acrylic acid alkyl ester having a C 1-18 alkyl group on a support or release sheet A pressure-sensitive adhesive sheet obtained by forming a thin film composed of a blend containing at least 1 to 100 parts by weight of an acrylic polymer (B) having a radiation-polymerizable group in the side chain, followed by radiation crosslinking.   The pressure-sensitive adhesive sheet according to claim 1, wherein the support is a sheet-like optical component.   Radiation at least in the side chain with respect to 100 parts by weight of the acrylic polymer (A) obtained by polymerizing a monomer mainly composed of alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms. A method for producing a pressure-sensitive adhesive sheet, comprising blending 1 to 100 parts by weight of an acrylic polymer (B) having a polymerizable group, forming a thin film on a support or a release sheet, and then performing radiation crosslinking. .