JP6232833B2 - Adhesive sheet and speaker - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive sheet that can be used for fixing decorative members such as punching sheets and various electronic components.

  In the manufacturing process of an electronic device, an adhesive sheet is used for the purpose of fixing various components constituting the electronic device. As a speaker provided in a television, radio, personal computer, and various mobile terminals, a punching sheet having a through hole is often fixed to the casing with an adhesive sheet. As the pressure-sensitive adhesive sheet used for the above-mentioned application, a light-shielding pressure-sensitive adhesive sheet is often used for the purpose of preventing a deterioration in design properties due to the visual recognition of the pressure-sensitive adhesive sheet.

  As the light-shielding pressure-sensitive adhesive sheet, for example, a double-sided pressure-sensitive adhesive sheet using a black acrylic pressure-sensitive adhesive in which 2 parts by weight of a black pigment is added to 100 parts by weight of an acrylic polymer and a nonwoven fabric substrate is known (for example, Patent Document 1).

  However, the pressure-sensitive adhesive sheet often contains, for example, a large amount of carbon black in the pressure-sensitive adhesive layer for the purpose of imparting a higher level of light-shielding properties. Although it is excellent in performance, it may cause a decrease in the adhesion strength to the adherend, the holding force in the shearing direction, and the constant load holding force in the 90-degree direction.

  On the other hand, in the past, organic solvent-type pressure-sensitive adhesives have been widely used for forming the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet. There is a need to provide a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed using an emulsion-type pressure-sensitive adhesive instead of the above.

  As a light-shielding pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed using the emulsion-type pressure-sensitive adhesive, for example, a water-dispersible acrylic polymer as a main component and a pressure-sensitive adhesive composition containing a colorant are formed into a sheet shape. A light-shielding pressure-sensitive adhesive sheet having a light-shielding pressure-sensitive adhesive layer obtained in this manner, wherein the light-shielding pressure-sensitive adhesive sheet has a total light transmittance of 1% or less (see, for example, Patent Document 2). ).

  However, when an emulsion-type pressure-sensitive adhesive is used to form a pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet, the effect of a colorant such as carbon black is greater than when a solvent-type pressure-sensitive adhesive is used. In some cases, the cohesive force may be significantly reduced. As a result, the adhesion force to the adherend, the holding force in the shear direction, and the constant load holding force in the 90 degree direction may be significantly reduced. In addition, the pressure-sensitive adhesive sheet in which the amount of the colorant contained in the pressure-sensitive adhesive layer is simply adjusted to maintain the pressure-sensitive adhesive performance does not have a practically sufficient light-shielding property, and particularly in applications where high design properties are required. In some cases, the color may be lowered.

JP 2009-263593 A Japanese Patent Laid-Open No. 2007-154078

  The problem to be solved by the present invention is that it has a light shielding property at a level capable of retaining excellent color even when used in applications requiring high design properties, and is excellent for adherends. It is to provide a pressure-sensitive adhesive sheet having an adhesive force, a holding force in a shear direction, and a constant load holding force in a 90-degree direction.

  In addition, the second problem to be solved by the present invention is an excellent color tone or the like even when using an emulsion type acrylic pressure-sensitive adhesive, or when used for applications requiring high design properties. To provide a pressure-sensitive adhesive sheet that has a light-shielding property at a level that can be held, and that has an excellent adhesion to the adherend, a holding force in the shear direction, and a constant load holding force in the 90-degree direction. .

  In addition, the third problem to be solved by the present invention is a high problem for speakers and the like because it has excellent light-shielding properties even when used for fixing decorative members such as punching sheets constituting the speakers and the like. It is to provide a pressure-sensitive adhesive sheet that can be given design properties and has an excellent adhesive force, a holding force in a shear direction, and a constant load holding force in a 90-degree direction with respect to an adherend.

  The present inventors not only reduce the amount of the colorant contained in the pressure-sensitive adhesive layer, but also use a nonwoven fabric substrate having a total light transmittance of 5% to 70% as the nonwoven fabric substrate. It has been found that a pressure-sensitive adhesive sheet having a light-shielding property capable of imparting design properties, an excellent adhesive force, a holding force in the shearing direction, and a constant load holding force in the 90-degree direction can be obtained.

  That is, this invention is an adhesive sheet which has an adhesive layer (B) on the single side | surface or both surfaces of the nonwoven fabric base material (A) whose total light transmittance measured according to JISK7136 is 5%-70%, The pressure-sensitive adhesive layer (B) is a layer formed using a pressure-sensitive adhesive containing the polymer (b1) and one or more colorants (b2) selected from the group consisting of pigments and dyes. In addition, the present invention relates to a pressure-sensitive adhesive sheet, wherein the colorant (b2) is contained in a range of 0.1% by mass to 1% by mass with respect to the entire pressure-sensitive adhesive layer (B).

  The pressure-sensitive adhesive sheet of the present invention has an excellent shielding property (light-shielding property) against light and the like, and has an excellent adhesion force to an adherend, a holding force in a shear direction, and a constant load holding force in a 90-degree direction. In particular, it can be used for applications that require high design properties. For example, a decorative member constituting a speaker of a television, a radio, an audio product, a personal computer, etc., or a decorative member constituting an exhaust port. It can be suitably used for fixation. In particular, the pressure-sensitive adhesive sheet can be suitably used for fixing a punching sheet constituting a speaker or the like that is required to have a higher design.

  In addition, the pressure-sensitive adhesive sheet of the present invention has excellent shielding properties (light-shielding properties) against light and the like even when an emulsion-type acrylic pressure-sensitive adhesive is used instead of the conventional solvent-type acrylic pressure-sensitive adhesive. Since it has an excellent adhesive force, a holding force in the shearing direction, and a constant load holding force in the 90-degree direction, it is possible to reduce the influence on the environment and the human body.

  The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (B) on one side or both sides of a nonwoven fabric substrate (A) having a total light transmittance of 5% to 70% measured according to JIS K7136. The pressure-sensitive adhesive layer (B) is a layer formed using a pressure-sensitive adhesive containing the polymer (b1) and one or more colorants (b2) selected from the group consisting of pigments and dyes. And the said coloring agent (b2) is contained in 0.1 mass%-1 mass% with respect to the said adhesive layer (B) whole, It is characterized by the above-mentioned.

  As the pressure-sensitive adhesive sheet, it is preferable to use a sheet having a total thickness of 200 μm or less, and using a sheet having a thickness of 100 μm to 200 μm is particularly excellent for an adherend having a through-hole such as a punching sheet. It is preferable because it can exhibit high adhesive strength.

  As the pressure-sensitive adhesive sheet, a sheet having a total light transmittance of 50% or less measured according to JIS K7136 is preferably used, and a sheet having a range of 0.1% to 50% is preferably used. It is preferable for maintaining a good light shielding property. In particular, when the adhesive sheet is used for fixing a decorative member constituting a speaker or the like, JIS K7136 is provided with JIS K7136 for imparting an appropriate light shielding property to the speaker and the like and providing a higher level of design. Therefore, it is preferable to use a pressure-sensitive adhesive sheet having a total light transmittance of 40% or less, more preferably 0.1% to 40%, and more preferably 0.1 to 10%. It is particularly preferable to do this.

  As a nonwoven fabric base material (A) which comprises the said adhesive sheet, the thing whose total light transmittance measured according to JISK7136 is 5%-70% is used. By using a nonwoven fabric substrate having the above-mentioned total light transmittance, it is possible to maintain good light shielding properties.

  The nonwoven fabric substrate (A) preferably has a total light transmittance of 10% to 60%, and is preferably 15% to 35% for the adherend. It is preferable because excellent light shielding properties can be maintained without impairing the adhesive force and the constant load holding force. In addition, the total light transmittance of the said nonwoven fabric base material (A) can be adjusted by the method of coloring the conventional nonwoven fabric using a coloring agent, the method of raising the density of a nonwoven fabric, etc., for example. As the non-woven fabric substrate (A), it is possible to impart excellent design properties to the final product and impart appropriate light-shielding properties without impairing the holding force in the shear direction and the constant load holding force in the 90-degree direction of the pressure-sensitive adhesive sheet. Therefore, it is preferable to use a nonwoven fabric substrate colored with a colorant.

  As the nonwoven fabric substrate (A), it is preferable to use a material having a thickness of 10 μm to 200 μm, and it is preferable that a material having a thickness of 15 μm to 80 μm is used. Since the base material (A) is appropriately impregnated, the adhesion between the nonwoven fabric base material (A) and the pressure-sensitive adhesive layer (B) can be improved.

The basis weight of the nonwoven fabric base material (A) is not particularly ^limited, it is preferably in the range of ^{5g / m 2 ~25g / m 2} , in the range of ^{8g / m 2 ~20g / m 2} , Adhesion between the nonwoven fabric substrate (A) and the pressure-sensitive adhesive layer (B) can be improved.

Density of the nonwoven fabric base material (A) is not particularly limited, is preferably in the range of 0.1 to 0.8 g / cm ^3, in the range of 0.3-0.6 g / cm ³ The adhesion between the nonwoven fabric substrate (A) and the pressure-sensitive adhesive layer (B) can be improved.

  As the nonwoven fabric substrate (A), a colored nonwoven fabric can be used.

  As said colored nonwoven fabric, what colored the nonwoven fabric (a) manufactured previously, for example using a coloring agent can be used.

  Examples of the non-woven fabric (a) include non-woven fabric obtained by using chemical fibers such as manila hemp, wood pulp, rayon, acetate fiber, polyester fiber, vinylon fiber (polyvinyl alcohol fiber), polyamide fiber, and mixtures thereof. Can be used.

  When manufacturing a nonwoven fabric (a) using the said fiber, you may use the conventionally known reinforcement | strengthening agent for the purpose of improving a tensile strength etc. further.

  Examples of the reinforcing agent include internal reinforcing agents such as polyacrylamide resins, urea-formaldehyde resins, melamine-formaldehyde resins, and epoxy-polyamide resins; starch, viscose, carboxymethylcellulose, polyvinyl alcohol, polyacrylamide, and the like. An external additive reinforcing agent or the like can be used. Among these, as the reinforcing agent, it is preferable to use a polyamide / epichlorohydrin resin, which is an epoxy-polyamide resin, as an internal additive reinforcing agent.

  The internal additive reinforcing agent is preferably used in the range of 0.2% by mass to 1% by mass with respect to the mass of the nonwoven fabric (a), and is used in the range of 0.3% by mass to 0.5% by mass. It is more preferable.

  Examples of the colorant that can be used in the production of the nonwoven fabric substrate (A) include direct dyes, reactive dyes, sulfur dyes, basic dyes, acid dyes, metal-containing acid dyes, indigo dyes, selenium dyes, disperse dyes, and cationic dyes. Dyes such as dyes; pigments such as organic pigments and inorganic pigments can be used alone or in combination of two or more. As the colorant, it is preferable to use a black colorant containing carbon black or the like in order to obtain a nonwoven fabric substrate (A) having a total light transmittance in the above range.

  As the colorant, one containing a thermoplastic resin as a binder component can be used for the purpose of further strengthening the adhesion of the pigment or the like to the nonwoven fabric (a). Examples of the thermoplastic resin that can be used include acrylic resins, polyurethane resins, polyester resins, and chlorinated polyolefin resins.

  In addition, as the colorant, for the purpose of further strengthening the adhesion of the pigment or the like to the nonwoven fabric (a), aluminum sulfate or polyamine dicyan low polymer is used within the range not impairing the effects of the present invention. A fixing agent such as can be used.

  As a method for producing the nonwoven fabric substrate (A), a method of impregnating a nonwoven fabric (a) with a colorant and drying (pigment exhaust dyeing method), a fiber forming the nonwoven fabric (a) is used with the colorant. And a method of producing a nonwoven fabric using the fibers after coloring and drying.

  Examples of the method for producing a nonwoven fabric using the colored fibers include known wet methods, and various paper machines using a circular net paper machine, a short net paper machine, a long net paper machine, an inclined short net paper machine, and the like. Law.

  The pressure-sensitive adhesive sheet of the present invention is not obtained by simply using the nonwoven fabric substrate (A) having the predetermined total light transmittance, but on one or both sides of the specific nonwoven fabric substrate (A), a pigment and It has an adhesive layer (B) containing a specific amount of one or more colorants (b2) selected from the group consisting of dyes. By combining the non-woven fabric substrate (A) and the pressure-sensitive adhesive layer (B), a light shielding property at a level capable of imparting a further excellent high design property, and an excellent adhesive force to an adherend, Both the holding force in the shear direction and the constant load holding force in the 90-degree direction can be achieved.

  The pressure-sensitive adhesive layer (B) constituting the pressure-sensitive adhesive sheet of the present invention uses a pressure-sensitive adhesive containing the polymer (b1) and one or more colorants (b2) selected from the group consisting of pigments and dyes. Among the pressure-sensitive adhesive layers to be formed, the solid content of the colorant (b2) is included in the range of 0.1% by mass to 1% by mass with respect to the entire pressure-sensitive adhesive layer (B).

  As the pressure-sensitive adhesive layer (B), the light-shielding property at a level capable of imparting high designability to the pressure-sensitive adhesive sheet, the excellent adhesion to the adherend, the holding force in the shear direction, and the constant load holding force in the 90-degree direction In order to achieve both, the solid content of the colorant (b2) should be included in the range of 0.1% by mass to 0.8% by mass with respect to the entire pressure-sensitive adhesive layer (B). It is more preferable to use those included in the range of 0.1% by mass to 0.5% by mass, and it is preferable to use those included in the range of 0.2% by mass to 0.5% by mass. Particularly preferred.

  As the pressure-sensitive adhesive layer (B), it is preferable to use a pressure-sensitive adhesive layer having a total light transmittance of 80% or less measured according to JIS K7136, and 60% for imparting further design properties. It is more preferable to use a pressure-sensitive adhesive layer that is as follows, and it is even more preferable to use a pressure-sensitive adhesive layer that is 50% or less. The lower limit value of the total light transmittance of the pressure-sensitive adhesive layer (B) has an even better design, an excellent adhesion to the adherend, a holding force in the shear direction, and a constant load holding force in the 90-degree direction. In order to achieve both high dimensions, it is preferable that the content is 1% or more.

  As the colorant (b2), the same colorants as exemplified as those that can be used in producing the nonwoven fabric substrate (A) can be used. For example, direct dyes, reactive dyes, sulfur dyes, Basic dyes, acid dyes, metal-containing acid dyes, indigo dyes, selenium dyes, disperse dyes, cationic dyes and other dyes; organic pigments, inorganic pigments and other pigments can be used alone or in combination of two or more.

  As the colorant (b2), a black colorant containing carbon black or the like is used in forming the pressure-sensitive adhesive layer (B) having the total light transmittance of 1% to 80%. Is preferred.

  The pressure-sensitive adhesive that can be used to form the pressure-sensitive adhesive layer (B) includes the predetermined colorant (b2), the polymer (b1), and a solvent, a crosslinking agent, and the like as necessary. Can be used.

  Specifically, the pressure-sensitive adhesive is an emulsion-type pressure-sensitive adhesive (b) or a solvent-type pressure-sensitive adhesive containing the polymer (b1), the colorant (b2), a solvent, and a cross-linking agent as necessary. It is preferable to use an emulsion-type pressure-sensitive adhesive from the viewpoint of reducing the environmental burden when manufacturing a pressure-sensitive adhesive sheet.

  As the emulsion type pressure-sensitive adhesive (b), for example, a polymer (b1) and a colorant (b2) dispersed in a solvent such as an aqueous medium can be used.

  As the polymer (b) contained in the pressure-sensitive adhesive, for example, an acrylic polymer can be used.

  As the acrylic polymer, for example, a polymer obtained by polymerizing a monomer containing a (meth) acrylate having a C 4-8 alkyl group and a vinyl monomer having a carboxyl group is used. Can do. By using the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms, it is possible to further improve the adhesion, adherence in the shear direction, and maintain constant load in the 90 degree direction to the adherend. The provided adhesive layer (B) can be formed.

  Examples of the (meth) acrylate having an alkyl group having 4 to 8 carbon atoms include 2-ethylhexyl acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, isooctyl (meta ) (Meth) acrylates such as acrylate and n-octyl (meth) acrylate can be used. Among them, it is preferable to use 2-ethylhexyl acrylate and n-butyl acrylate. Particularly, the combined use of n-butyl acrylate and 2-ethylhexyl acrylate results in adhesion to the adherend and retention in the shear direction. It is more preferable for forming a pressure-sensitive adhesive layer having an even better adhesive force with respect to a constant load holding force in the 90-degree direction.

  The (meth) acrylate having an alkyl group having 4 to 8 carbon atoms is used in a range of 50% by mass to 99% by mass with respect to the total amount of monomers used for the production of the acrylic polymer. Is preferable, it is more preferably used in the range of 70% by mass to 98% by mass, and further preferably in the range of 90% by mass to 98% by mass.

  Examples of the vinyl monomer having a carboxyl group that can be used in the production of the acrylic polymer include acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, phthalic acid, phthalic anhydride, and crotonic acid. One kind or a combination of two or more kinds can be used. As the vinyl monomer having a carboxyl group, it is preferable to use acrylic acid and methacrylic acid, and in particular, it is possible to use a combination of acrylic acid and methacrylic acid. It is possible to form a pressure-sensitive adhesive layer having a holding force of 90 ° and a constant load holding force of 90 ° direction.

  The vinyl monomer having a carboxyl group is preferably used in the range of 0.5% by mass to 10% by mass with respect to the total amount of monomers used for the production of the acrylic polymer. More preferably, it is used in the range of 5% by mass to 5% by mass, and in the range of 1.5% by mass to 4% by mass, the cross-linking reaction with the cross-linking agent to be described later easily proceeds favorably. It is more preferable when forming a pressure-sensitive adhesive layer having excellent adhesive strength, shearing direction holding force, and 90 ° direction constant load holding force with respect to the adherend.

  When the acrylic monomer and methacrylic acid are used in combination as the vinyl monomer having a carboxyl group, the molar equivalent ratio of methacrylic acid and acrylic acid [methacrylic acid / acrylic acid] is preferably 0.2 or more, It is more preferably 1 or more, further preferably 2 or more, and particularly preferably 3 or more. The upper limit of the molar equivalent ratio of methacrylic acid and acrylic acid is 33. The pressure-sensitive adhesive layer has excellent adhesion to the adherend, holding power in the shear direction, and constant load holding power in the 90-degree direction. Is preferable in forming.

  As a monomer that can be used when the acrylic polymer is produced, other monomers can be used as necessary in addition to those described above.

  As said other monomer, methyl (meth) acrylate, ethyl (meth) acrylate etc. can be used, for example, C2 or less alkyl groups, such as methyl (meth) acrylate and ethyl (meth) acrylate, etc. It is particularly preferable to use a (meth) acrylate having a high molecular weight in order to form a pressure-sensitive adhesive layer having excellent constant load retention in the 90-degree direction.

  The (meth) acrylate having an alkyl group having 2 or less carbon atoms is preferably used in the range of 1% by mass to 10% by mass with respect to the total amount of monomers used for the production of the acrylic polymer. The use in the range of 3% by mass to 5% by mass is particularly preferable for forming a pressure-sensitive adhesive layer having excellent constant load holding force in the 90-degree direction.

  Moreover, as said other monomer, the vinyl monomer which has a nitrogen atom can be used. The vinyl monomer having a nitrogen atom is preferably used in combination with the vinyl monomer having a carboxyl group, particularly for forming a pressure-sensitive adhesive layer having excellent constant load retention in the 90-degree direction.

  Examples of the vinyl monomer having a nitrogen atom include N-vinylpyrrolidone, N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam, N-cyclohexylmaleimide, N-butylmaleimide, N-phenylmaleimide, N -(Meth) acryloylmorpholine, N- (meth) acryloylpyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N- (meth) acryloyl-4-piperidone, acrylonitrile, (meth) acrylamide, N , N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-methylene (Meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate Can be used alone or in combination of two or more, and N-vinylpyrrolidone is preferably used.

  The vinyl monomer having a nitrogen atom is preferably used in the range of 1% by mass to 5% by mass with respect to the total amount of monomers used for the production of the acrylic polymer, and 0.5% by mass. It is particularly preferable to use in the range of% to 1.5% by mass in forming a pressure-sensitive adhesive layer having excellent constant load holding force in the 90-degree direction.

  The use ratio (molar ratio) of the vinyl monomer having a nitrogen atom and the vinyl monomer having a carboxyl group is X as the number of moles of the vinyl monomer having a nitrogen atom, and the vinyl having the carboxyl group. It is preferable that the molar ratio X / Y when the number of moles of the monomer is Y is in the range of 0.05 to 1, more preferably in the range of 0.2 to 0.5. In particular, it is preferable for forming a pressure-sensitive adhesive layer excellent in a constant load holding force in the 90-degree direction.

  As said other monomer, in addition to what was mentioned above, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl as needed Vinyl monomers having a hydroxyl group such as (meth) acrylate; diacetone acrylamide, diacetone methacrylamide, acrolein, formyl styrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, diacetone acrylate, diacetone methacrylate, acetonitrile acrylate , Monomers having keto group or aldehyde group such as 2-hydroxypropyl acrylate acetoacetate and butanediol acrylate acetate; methylo such as N-methylolacrylamide It can be used a monomer having a Rhodia Nicca Ltd. Sipomer PAM-100, PAM-200, PAM-300 phosphate groups and the like; monomers having an Le group.

  As a method for producing the acrylic polymer, for example, in the case of producing an emulsion type acrylic pressure-sensitive adhesive in which the acrylic polymer is dispersed in an aqueous medium, the aforementioned monomer is polymerized by an emulsion polymerization method. The method of doing is mentioned. In the polymerization, various polymerization methods such as a batch charging method and a dropping method can be employed. More specifically, as the emulsion polymerization method, it is preferable to employ a method in which the monomer and the polymerization initiator are respectively added dropwise to a reaction vessel charged with an aqueous medium to perform emulsion polymerization.

  In carrying out the emulsion polymerization, an anionic emulsifier, a nonionic emulsifier, other dispersion stabilizers and the like can be used for the purpose of ensuring polymerization stability.

  Examples of the anionic emulsifier include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, and the like. As the nonionic emulsifier, for example, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether and the like can be used.

  As the emulsifier, it is preferable to use an emulsifier having a polymerizable unsaturated group in the molecule, generally called “reactive emulsifier”. Examples of the reactive emulsifier include Latemul PD-104 [manufactured by Kao Corporation], Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd.], Adekaria Soap SE-10 [manufactured by ADEKA Corporation], Eleminol. And JS-20 [manufactured by Sanyo Chemical Industries, Ltd.]. Use of a reactive emulsifier is preferable because moisture resistance is improved in addition to polymerization stability.

  When manufacturing the said acrylic polymer, a polymerization initiator can be used as needed. Examples of the polymerization initiator include 4,4-azobis (4-cyanopentanoic acid), 2,2 ′,-azobis (2-methylpropionamidine) dihydrochloride, 2,2′-azobis (2-methylpropionamidine). ) Sulfate, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [N- (2-alkoxyethyl) -2-methylpropionamidine] hydrate, 2,2 '-Azobis (N, N'-dimethyleneisobutylamidine) dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2 -(2-imidazolin-2-yl) propane] sulfate, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [ 2- (5-Methyl 2-Imidazolin-2-yl) propane] sulfate, 2-2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane] dihydrochloride, azo initiators such as 2,2′-azobis (2-methylpropanamide oxime), persulfuric acid Persulfate initiators such as potassium, ammonium persulfate, sodium persulfate, peroxide initiators such as benzoyl peroxide, t-butyl hydroperoxide, hydrogen peroxide, and carbonyl initiators such as aromatic carbonyl compounds Redox initiators such as a combination of persulfate and sodium bisulfite, a combination of peroxide and sodium ascorbate, and the like can be used. Among these, the use of an azo initiator or a persulfate initiator is preferable because it has excellent polymerization stability and a desired adhesive performance is easily obtained.

  Moreover, when manufacturing the said acrylic polymer, a chain transfer agent can be used as needed for the purpose of adjusting the molecular weight of an acrylic polymer.

  As the chain transfer agent, for example, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimethylcapto-1-propanol and the like can be used. .

  As the acrylic polymer obtained by the above method, it is preferable to use a polymer having a weight average molecular weight of 500,000 to 1,200,000, and it is preferable to use a polymer having a weight average molecular weight of 600,000 to 1,000,000. It is preferable for obtaining a pressure-sensitive adhesive sheet having an excellent adhesion to the adherend, a holding force in the shearing direction, and a constant load holding force in the 90-degree direction.

  The weight average molecular weight is a value obtained by standard gel conversion using gel permeation chromatography (GPC). As measurement conditions, TSKgel GMHXL [manufactured by Tosoh] was used as the column, the column temperature was 40 ° C., the eluent was tetrahydrofuran, the flow rate was 1.0 mL / min, and the standard polystyrene was TSK standard polystyrene.

(Particle size)
The average particle diameter of the acrylic polymer particles is not particularly limited, but is preferably 100 nm to 1000 nm, and 150 nm to 500 nm is agglomerated or settled even when stored for a long time. It is preferable because it is difficult to occur and has excellent dispersion stability. The average particle diameter refers to a 50% median diameter based on the volume of the emulsion particles, and the numerical values are based on values obtained by measurement by a dynamic light scattering method.

  Examples of the aqueous medium in which the acrylic polymer can be dispersed include water, organic solvents miscible with water, and mixtures thereof. Examples of the organic solvent miscible with water include alcohols such as methanol, ethanol, n-propanol and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol and propylene glycol; Alkyl ethers; lactams such as N-methyl-2-pyrrolidone, ethyl carbitol, ethyl cellosolve, butyl cellosolve, and the like. In the present invention, only water may be used, a mixture of water and an organic solvent miscible with water may be used, or only an organic solvent miscible with water may be used. From the viewpoint of safety and load on the environment, water alone or a mixture of water and an organic solvent miscible with water is preferable, and only water is particularly preferable.

  As the pressure-sensitive adhesive that can be used for forming the pressure-sensitive adhesive layer (B), in addition to those described above, those containing a tackifying resin can be used as necessary.

  As the tackifying resin, an emulsion type tackifying resin is preferably used if it is used for the emulsion type acrylic pressure-sensitive adhesive (b).

  Examples of the emulsion-type tackifying resin include rosin-based tackifying resin, polymerized rosin-based tackifying resin, rosin ester-based tackifying resin, polymerized rosin ester-based tackifying resin, rosin phenol-based tackifying resin, and disproportionated rosin. An ester tackifier resin, a hydrogenated rosin ester tackifier resin, an acid-modified rosin tackifier resin, a terpene tackifier resin, a terpene phenol tackifier resin, a petroleum resin tackifier resin, or the like can be used. A rosin ester-based tackifier resin and a polymerized rosin ester-based tackifier resin for forming a pressure-sensitive adhesive layer having excellent adhesion to metal and plastic adherends and a constant load holding force in the 90-degree direction. A rosin phenol-based tackifier resin or a petroleum resin-based tackifier resin can be preferably used.

  Among these, as the emulsion type tackifying resin, it is preferable to use the polymerized rosin ester tackifying resin and the rosin phenol tackifying resin, and the polymerized rosin ester tackifying resin and the rosin phenol tackifying resin. Is particularly preferable for forming a more excellent pressure-sensitive adhesive layer with a constant load holding force in the 90-degree direction.

  The tackifying resin is preferably used in the range of 5 to 40 parts by mass with respect to 100 parts by mass of the resin (solid content) containing the acrylic polymer, and in the range of 10 to 30 parts by mass. Is preferably used for forming a pressure-sensitive adhesive layer having excellent adhesion to the adherend and a constant load holding force in the 90-degree direction.

  When the polymerized rosin ester-based tackifier resin and the rosin phenol-based tackifier resin are used in combination, the polymerized rosin ester-based tackifier resin ranges from 5 to 20 parts by mass, and the rosin phenol-based tackifier. It is preferable to use the resin in the range of 5 to 20 parts by mass, which is preferable for forming a pressure-sensitive adhesive layer having excellent adhesive force and constant load holding force with respect to the adherend. A particularly preferred combination is a combination of 10 parts by mass of the polymerized rosin ester-based tackifier resin and 10 parts by mass of the rosin phenol-based tackifier resin.

  As the tackifying resin, those having a softening point of 100 ° C to 180 ° C are preferably used, more preferably those having a softening point of 120 ° C to 180 ° C, and those having a softening point of 130 ° C to 180 ° C. It is more preferable to use one having a temperature of 140 ° C. to 170 ° C., particularly when forming a pressure-sensitive adhesive layer having an excellent constant load holding force in the 90 ° C. direction.

  The pressure-sensitive adhesive layer (B) preferably has a crosslinked structure. For forming the cross-linked structure, a pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer (B) contains a cross-linking agent.

  Examples of the crosslinking agent include known epoxy crosslinking agents, silane crosslinking agents, isocyanate crosslinking agents, aziridine crosslinking agents, polyvalent metal salt crosslinking agents, metal chelate crosslinking agents, keto-hydrazide crosslinking agents, and oxazolines. A system crosslinking agent, a carbodiimide system crosslinking agent, etc. can be used. The crosslinking agent may be supplied during the production of the polymer (b1), or may be supplied after the organic solvent solution of the polymer (b1) or an aqueous dispersion thereof is produced and used as an adhesive. .

  Especially, it is preferable to use an epoxy-based crosslinking agent, a silane-based crosslinking agent, and an isocyanate-based crosslinking agent as the crosslinking agent because the gel fraction of the pressure-sensitive adhesive layer (B) can be easily adjusted to a desired range.

  The preferred crosslinking agent does not proceed with the crosslinking reaction immediately after the formation of the pressure-sensitive adhesive layer (B), but proceeds with the crosslinking reaction over a relatively long time. Therefore, the preferable cross-linking agent can advance the cross-linking reaction in a curing process that is often performed after forming the pressure-sensitive adhesive sheet by transferring the pressure-sensitive adhesive layer to the surface of the nonwoven fabric substrate (A). And there exists adhesiveness of a nonwoven fabric base material (A) and an adhesive layer (B), and various adhesive performance can be improved further.

  Rather than using the crosslinking agent in the middle of the production of the polymer (b1), the gel is supplied after the organic solvent solution of the polymer (b1) or its aqueous dispersion is produced and used as an adhesive. It is preferable because the fraction can be easily adjusted to a desired range, and the adhesion between the nonwoven fabric substrate (A) and the pressure-sensitive adhesive layer (B) and various pressure-sensitive adhesive properties can be further improved.

  Examples of the epoxy-based crosslinking agent include Denacol EX-832 [manufactured by Nagase Kasei Kogyo Co., Ltd.], Denacol EX-841 [manufactured by Nagase Kasei Kogyo Co., Ltd.], Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.], Tetrad X [Mitsubishi Gas Chemical Co., Ltd.] and the like can be used.

  Examples of the silane crosslinking agent include β- (3,4-epoxycyclohexylethyltrimethoxysilane [Z-6043; manufactured by Toray Dow Corning Co., Ltd.], γ-glycidoxypropyltrimethoxysilane [Z-6040; Toray Dow Corning Co., Ltd.], γ-glycidoxypropylmethyldiethoxysilane [KBE-402; Shin-Etsu Silicone Co., Ltd.], γ-glycidoxypropyltriethoxysilane [KBE-403; Shin-Etsu Silicone ( Co., Ltd.], 3-methacryloxypropylmethyldimethoxysilane [Z-6033; manufactured by Toray Dow Corning Co., Ltd.], 3-methacryloxypropyltrimethoxysilane [Z-6030; manufactured by Toray Dow Corning Co., Ltd.] 3-methacryloxypropylmethyldiethoxysilane [KBE-502; Shin-Etsu Chemical Co., Ltd. , 3-methacryloxypropyltriethoxysilane [KBE-503; manufactured by Shin-Etsu Chemical Co., Ltd.], 3-acryloxypropyltrimethoxysilane [Z-6530; manufactured by Toray Dow Corning Co., Ltd.], etc. be able to.

  As said isocyanate type crosslinking agent, Bernock DNW-5000 [made by DIC Corporation], Bernock DNW-5010 [made by DIC Corporation], Burnock DNW-5100 [made by DIC Corporation], Burnock DNW-5500 [DIC] AQUANATE 100 [Nippon Polyurethane Industry Co., Ltd.], AQUANATE 105 [Nippon Polyurethane Industry Co., Ltd.], AQUANATE 110 [Nippon Polyurethane Industry Co., Ltd.], AQUANATE 120 [Japan] Polyurethane Industry Co., Ltd.], Aquanate 130 [Nihon Polyurethane Industry Co., Ltd.], Aquanate 200 [Nihon Polyurethane Industry Co., Ltd.], Aquanate 210 [Nihon Polyurethane Industry Co., Ltd.], LS2319 Bayer Urethane Co., Ltd.], LS2336 [Sumika Bayer Urethane Co., Ltd.], Bayhydr 3100 [manufactured by Sumika Bayer Urethane Co., Ltd.] and the like can be used.

  The said crosslinking agent can be used in the range from which the gel fraction of an adhesive layer (B) becomes a desired range. For example, if an epoxy-based crosslinking agent is used as the crosslinking agent, the epoxy-based crosslinking agent is used in a range of 0.01 parts by mass to 0.1 parts by mass with respect to 100 parts by mass of the acrylic polymer. It is preferable to do. In addition, when a silane crosslinking agent is used as the crosslinking agent, the silane crosslinking agent is in a range of 0.005 parts by mass to 0.5 parts by mass with respect to 100 parts by mass of the acrylic polymer. It is preferable to use it. If an isocyanate crosslinking agent is used as the crosslinking agent, the isocyanate crosslinking agent is used in the range of 0.005 to 0.5 parts by mass with respect to 100 parts by mass of the acrylic polymer. It is preferable.

  As the pressure-sensitive adhesive that can be used for forming the pressure-sensitive adhesive layer (B), one having a solid content in the range of 40% by mass to 70% by mass is used for the purpose of further improving the dispersion stability. It is preferable to do.

  As the adhesive used in the present invention, for example, the gel fraction of the adhesive layer which is substantially not cross-linked and obtained by applying the adhesive to a release liner and drying in an environment of 100 ° C. It is preferable to use those having an initial gel fraction of 15% by mass or less, more preferably 10% by mass or less, and more preferably 3% by mass or less. In order to further improve various adhesive performances such as adhesion between the base material (A) and the pressure-sensitive adhesive layer (B), 180 ° peel adhesive strength, holding strength, and constant load holding strength, it is more preferable. In addition, an initial stage gel fraction can be adjusted by setting suitably the kind and usage-amount of a polymerization initiator which can be used when manufacturing an acrylic polymer, polymerization temperature, etc.

  Examples of the pressure-sensitive adhesive that can be used for forming the pressure-sensitive adhesive layer (B) include a base (such as aqueous ammonia and amines), an acid, a plasticizer, a softener, an antioxidant, and the like for adjusting pH as necessary. Using fillers such as glass and plastic fibers, balloons, beads, metal powders, film formation aids, leveling agents, wetting agents, thickeners (viscosity modifiers), water repellents, antifoaming agents, etc. Also good. It is preferable to use them in the range of 0% by mass to 1% by mass, respectively.

The pressure-sensitive adhesive layer (B) preferably has a thickness in the range of 50 μm to 200 μm, more preferably in the range of 80 μm to 180 μm, and a range of 100 μm to 150 μm. More preferably.
Yes. When the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer (B) on both sides of the nonwoven fabric substrate (A), the total thickness of the pressure-sensitive adhesive layers (B) on both sides is within the above range. The light-shielding property and the adhesive performance can be achieved in a balanced manner, which is preferable.

  The pressure-sensitive adhesive sheet of the present invention can be produced, for example, by applying the pressure-sensitive adhesive on one side or both sides of the predetermined nonwoven fabric substrate (A) using a roll coater, a die coater, or the like, and drying (so-called, Direct coating method). The separator may be laminated | stacked on the surface of the adhesive layer (B) which comprises the adhesive sheet obtained by the said method.

  Moreover, the pressure-sensitive adhesive sheet of the present invention forms the pressure-sensitive adhesive layer (B) by applying the pressure-sensitive adhesive on the surface of the release liner in advance using a roll coater, a die coater or the like, and then drying, It can also manufacture by the method of transcribe | transferring an adhesive layer (B) to a nonwoven fabric base material (A) (so-called transfer method).

  It is preferable that the pressure-sensitive adhesive sheet produced by any of the above methods is then cured for 48 hours or more in the range of 20 ° C. to 50 ° C. in order to advance the crosslinking reaction of the pressure-sensitive adhesive layer (B).

  The post-curing pressure-sensitive adhesive layer (B) was dried in a mass of the pressure-sensitive adhesive layer (B) formed after drying and immersed in toluene at 25 ° C. for 24 hours and then dried at 105 ° C. The gel fraction calculated based on the mass of the object is preferably in the range of 20% by mass to 50% by mass, and in the range of 30% by mass to 45% by mass, the holding force in the shear direction and the 90 degree direction This is more preferable because the constant load holding force can be further improved.

  The pressure-sensitive adhesive sheet of the present invention obtained by the above method can be used exclusively for applications that require good light-shielding properties and high design properties.

  Therefore, the pressure-sensitive adhesive sheet of the present invention has an excellent constant load holding power in addition to good light-shielding properties. Therefore, the punching sheet is used in speakers provided in household appliances and electronic devices such as televisions, radios, audio products, and personal computers. It can be suitably used for the purpose of fixing a decorative member such as.

  Next, the present invention will be described in detail with reference to examples and comparative examples. The evaluation method of each characteristic of the double-sided PSA sheet obtained in Examples and Comparative Examples is as follows.

[Measurement method of total light transmittance of nonwoven fabric substrate]
A non-woven fabric substrate was cut into a square having a length of 50 mm and a width of 50 mm (area 25 cm ² ) to produce a test piece, and a reflection / transmittance meter HR-100 type [manufactured by Murakami Color Research Laboratory Co., Ltd.] The total light transmittance was measured according to JIS K 7136.

[Measurement method of basis weight of nonwoven fabric substrate]
A non-woven fabric substrate was cut into a square of 100 cm length × 100 cm width (area 1 m ² ) to produce a test piece, and per unit area using an electronic balance [manufactured by Shimadzu Corporation, model number: AEL-40SM] The mass of was measured. The basis weight was calculated according to the following formula.

Basis weight (g / m ² ) = mass (g) / area (m ² )

[Measurement method of total light transmittance of pressure-sensitive adhesive layer]
The water-dispersed acrylic pressure-sensitive adhesive obtained in Preparation Example was applied to a release liner, dried in an environment of 100 ° C., and moisture was removed, thereby preparing a pressure-sensitive adhesive layer having a thickness of 65 μm.

  After peeling off the release liner, the total light transmittance of the pressure-sensitive adhesive layer was measured according to JIS K 7136 using a reflection / transmittance meter HR-100 type [manufactured by Murakami Color Research Laboratory Co., Ltd.].

[Measurement method of total light transmittance of double-sided PSA sheet]
A test piece was prepared by cutting the double-sided PSA sheets obtained in Examples and Comparative Examples into squares having an area of 25 cm ² . The total light transmittance of the test piece was measured according to JIS K 7136 using a reflection / transmittance meter HR-100 [manufactured by Murakami Color Research Laboratory Co., Ltd.].

[Measurement method of gel fraction]
What cut | disconnected the double-sided adhesive sheet obtained by the Example and the comparative example to the magnitude | size (area 20cm < ² >) of length 50mm x width 40mm was used as the test piece. Note that before the production of the double-sided pressure-sensitive adhesive sheet was measured mass of nonwoven substrate used for the production of (G ₀₎ in advance.

Next, the mass (G ₁ ) of the test piece was measured. Next, the test piece was immersed in toluene at room temperature for 24 hours, and then filtered through a 300-mesh wire mesh to separate a residue that was insoluble in toluene and dried at 105 ° C. for 1 hour. The mass (G2) of the residue was measured. Wherein the mass of non-woven fabric substrate (G _0), and the mass of the before immersion of the test piece (G _1), the value of the residue mass (G _2), according to the following formula, was calculated gel fraction.

Gel fraction (% by mass) = [(G ₂ −G ₀ ) / (G ₁ −G ₀ )] × 100

[Design evaluation method]
The release liners of the double-sided pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were peeled off, and the surface of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet was visually observed under an environment of indoor lighting of 500 lux. The observations were made by 5 evaluators. Of the evaluations by the five evaluators, the most evaluated result was the design evaluation of the double-sided PSA sheet.

  The surface of the pressure-sensitive adhesive layer has a deep and deep color tone and excellent jetness, “◎”, the darkness is slightly low but practically black, “◯”, clearly black The light color (gray) that was slightly inferior in quality was evaluated as “Δ”, and the color on the back surface of the double-sided PSA sheet was confirmed as “x”.

[Measurement method of adhesive strength (180 ° peel adhesive strength)]
The 180 ° peel adhesive strength was measured according to JIS Z 0237.

  A double-sided PSA sheet obtained in Examples and Comparative Examples is backed by attaching a polyethylene terephthalate (PET) film with a thickness of 25 μm to the adhesive layer on one side and cut into a size of 300 mm in length and 20 mm in width Was used as a test piece.

  The test piece was placed on the adherend so that the other pressure-sensitive adhesive layer of the test piece was in contact with the surface of the adherend which was a stainless steel plate (SUS304 steel plate), an aluminum plate, and an acrylic resin plate. -They were affixed by one-way pressurization with a 2 kg roller in an environment of 50% RH.

  The patch was allowed to stand in an environment of 23 ° C. and 50% RH for 1 hour, and then the test piece was rotated 180 degrees from the adherend using a Tensilon tensile tester [manufactured by A & D Co., Ltd., model: RTM-100]. The adhesive strength when peeled at a speed of 300 m / min was measured. The higher the measured value, the better the adhesion performance.

[Measurement method of constant load holding force in 90 ° direction]
A double-sided PSA sheet obtained in the Examples and Comparative Examples was backed by attaching a polyethylene terephthalate (PET) film with a thickness of 25 μm to the adhesive layer on one side and cut into a size of 100 mm in length and 10 mm in width Was used as a test piece.

  Next, in an environment of 23 ° C. and 50% RH, each adherend that is a stainless steel plate (SUS304 steel plate), an aluminum plate, or an acrylic resin plate is placed on the surface of the other adhesive layer of the test piece. The test piece and the adherend were pasted by applying two reciprocating pressures using a 2 kg roller (pasting area; length 50 mm × width 10 mm).

  After the patch is left in an environment of 23 ° C. and 50% RH for 1 hour, a surface of the adherend constituting the patch is horizontally placed on a constant load holding force meter (manufactured by Tester Sangyo Co., Ltd.). And fixed so as to be the upper surface. Next, a weight of 0.3 kg was attached to the end of the test piece constituting the patch, and a load of 0.3 kg was applied in the 90 ° direction with respect to the length direction of the patch.

  The time [unit: minute] until the test piece dropped from the patch was measured. The higher the measured value, the better the adhesion performance. In addition, the thing falling within 3 hours (180 minutes) was scarce in constant load holding power, and the thing hold | maintained more than that was evaluated that it was excellent in constant load holding power.

[Measurement method of holding force in shear direction]
The holding force was measured according to JIS Z 0237.

  The adhesive layer on one side of the double-sided PSA sheet obtained in Examples and Comparative Examples was lined with an aluminum foil having a thickness of 50 μm and cut into a size of 100 mm in length and 20 mm in width as a test piece. did.

  Next, in an environment of 23 ° C. and 50% RH, a stainless steel plate (SUS304 steel plate) was placed on the surface of the other adhesive layer of the test piece so that the affixing area was 20 mm × 20 mm, and 2 kg. They were pasted by one reciprocating pressure using a roller.

  The patch was allowed to stand in an environment of 23 ° C. and 50% RH for 1 hour, and then in a 70 ° C. environment, the patch was placed on a holding force meter with a thermostatic bath [manufactured by Tester Sangyo Co., Ltd.] in its shear direction (long (Direction) was fixed so as to be perpendicular to the horizontal. Next, a load of 0.5 kg was applied in the shearing direction of the patch by attaching a weight of 0.5 kg to the end of the test piece constituting the patch. The time until the test piece fell from the patch was measured. In addition, the test piece which did not fall after 1440 minutes (24 hours) passed was described as 1440 <. The higher the measured value, the better the adhesion performance.

(Preparation Example 1)
<Preparation of emulsion>
In a container, 75 g of ion-exchanged water and Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 25% by mass] as a surfactant and Latem PD-104 [Kao Co., Ltd .; active ingredient 20% by mass] 37.5 g was added and dissolved uniformly. Thereto, 237.5 g of n-butyl acrylate, 237.5 g of 2-ethylhexyl acrylate, 15 g of methyl methacrylate, 10 g of acrylic acid, and 0.2 g of lauryl mercaptan were added and emulsified to obtain 632.7 g of an emulsion.

<Preparation of aqueous dispersion of water-dispersed acrylic copolymer>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 333.5 g of ion-exchanged water was added, and the temperature was raised to 60 ° C. while blowing nitrogen. While stirring, a part of the emulsion prepared above [7.59 g], 2.5 g of ammonium persulfate aqueous solution [6% by mass of active ingredient], 2.5 g of sodium hydrogen sulfite aqueous solution [6% by mass of active ingredient] were added, Polymerization was performed in 1 hour while maintaining 60 ° C. Subsequently, the remaining emulsion (625.11 g) and ammonium persulfate aqueous solution (50 g [active ingredient 1% by mass]) were added dropwise over 6 hours using a separate funnel while keeping the reaction vessel at 60 ° C. After completion of the dropwise addition, the reaction vessel was stirred for 1 hour while maintaining the temperature at 60 ° C. Next, 5 g [active ingredient 2% by mass] of sodium erythorbate aqueous solution was dropped and polymerized over 1 hour using another funnel, and then stirred for 1 hour while maintaining the reaction vessel at 60 ° C. Then, the contents were cooled and adjusted with aqueous ammonia (active ingredient 10% by mass) so that the pH was 7.5. This was filtered with a 200-mesh wire mesh to obtain an aqueous dispersion (1) [solid content concentration of 50% by mass] of an aqueous dispersion type acrylic copolymer. The acrylic copolymer had an average particle size of 339 nm and a weight average molecular weight of 670,000.

<Preparation of water-dispersed acrylic pressure-sensitive adhesive composition>
Superester E-865NT [made by Arakawa Chemical Industries, Ltd .; emulsion type polymerized rosin ester type tackifying resin, softening point to 1000 g of aqueous dispersion (1) of the above water dispersion type acrylic copolymer as tackifying resin 160 ° C., solid content concentration 50% by mass] 200 g, Surfinol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g as a leveling agent, Surfynol DF-110D [Air Products Japan] as an antifoaming agent Made by Co., Ltd.] 2.5 g was added.

  After mixing them, 1.5 g of a 10 mass% ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a cross-linking agent and stirred for 1 hour. Subsequently, 10 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] was added as a colorant, and the mixture was stirred for 1 hour, and water-dispersed acrylic adhesive An agent composition (1) was obtained. In addition, the total light transmittance of the 65-micrometer-thick adhesive layer prepared using the obtained water dispersion type acrylic adhesive composition (1) was 7.4%.

(Preparation Example 2)
A water-dispersed acrylic pressure-sensitive adhesive composition (2) was obtained in the same manner as in Preparation Example 1, except that the blending amount of PSM black C as the colorant was changed from 10 g to 6 g. The total light transmittance of the 65 μm-thick adhesive layer prepared using the water-dispersed acrylic pressure-sensitive adhesive composition (2) was 19.5%. The total light transmittance of the 55 μm thick adhesive layer was 28.8%, and the total light transmittance of the 70 μm thick adhesive layer was 19.0%.

(Preparation Example 3)
A water-dispersed acrylic pressure-sensitive adhesive composition (3) was obtained in the same manner as in Preparation Example 1, except that the blending amount of PSM black C as the colorant was changed from 10 g to 4 g. The total light transmittance of the 65 μm thick pressure-sensitive adhesive layer prepared using the water-dispersed acrylic pressure-sensitive adhesive composition (3) was 29.2%.

(Preparation Example 4)
A water-dispersed acrylic pressure-sensitive adhesive composition (4) was obtained in the same manner as in Preparation Example 1, except that the blending amount of PSM black C as a colorant was changed from 10 g to 2 g. In addition, the total light transmittance of the 65-micrometer-thick adhesive layer prepared using the water-dispersed acrylic adhesive composition (4) was 51.6%.

(Preparation Example 5)
Superester E-865NT [made by Arakawa Chemical Industries, Ltd .; emulsion-type polymerized rosin ester-based tackifier resin, softening point 160 ° C. to 1000 g of water-dispersed acrylic copolymer (1) 1000 g , Solid content concentration 50% by mass] 100 g, Tamanol E-200NT [Arakawa Chemical Industries, Ltd .; emulsion type rosin phenol-based tackifier resin, softening point 150 ° C., solid content concentration 53% by mass] 94.34 g, leveling agent Surfynol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g, and Surfynol DF-110D [manufactured by Air Products Japan Co., Ltd.] 2.5 g were added as an antifoaming agent.

  After mixing them, 1.5 g of a 10 mass% ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a cross-linking agent and stirred for 1 hour. Subsequently, 6 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] was added as a colorant, and the mixture was stirred for 1 hour, and water-dispersed acrylic adhesive An agent composition (1) was obtained. In addition, the total light transmittance of the 65-micrometer-thick adhesive layer prepared using the obtained water dispersion type acrylic adhesive composition (5) was 19.3%.

(Preparation Example 6)
Superester NS-121 [made by Arakawa Chemical Industries, Ltd .; emulsion type rosin ester type tackifying resin, softening point 125 ° C., 1000 g of water dispersion type acrylic copolymer aqueous dispersion (1) Solid content 50% by weight] 200 g, Surfinol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g as leveling agent, Surfynol DF-110D [Air Products Japan Co., Ltd.] as antifoaming agent Made] 2.5 g was added.

  After mixing them, 1.5 g of a 10 mass% ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a cross-linking agent and stirred for 1 hour. Subsequently, 6 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] was added as a colorant, and the mixture was stirred for 1 hour, and water-dispersed acrylic adhesive An agent composition (1) was obtained. In addition, the total light transmittance of the 65-micrometer-thick adhesive layer prepared using the obtained water dispersion type acrylic adhesive composition (6) was 19.2%.

(Preparation Example 7)
Superester NS-100H [made by Arakawa Chemical Industry Co., Ltd .; emulsion type rosin ester type tackifying resin, softening point 100 ° C. Solid content 50% by weight] 200 g, Surfinol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g as leveling agent, Surfynol DF-110D [Air Products Japan Co., Ltd.] as antifoaming agent Made] 2.5 g was added.

  After mixing them, 1.5 g of a 10 mass% ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a cross-linking agent and stirred for 1 hour. Subsequently, 6 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] was added as a colorant, and the mixture was stirred for 1 hour, and water-dispersed acrylic adhesive An agent composition (7) was obtained. The total light transmittance of the 65 μm-thick pressure-sensitive adhesive layer prepared using the obtained water-dispersed acrylic pressure-sensitive adhesive composition (7) was 19.2%.

(Preparation Example 8)
Emulsion AM-1000NT [manufactured by Arakawa Chemical Industries, Ltd .; emulsion-type petroleum resin-based tackifier resin, softening point 100 ° C., solids to 1000 g of water-dispersed acrylic copolymer aqueous dispersion (1) Partial concentration 50% by mass] 200 g, Surfinol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g as a leveling agent, Surfynol DF-110D [manufactured by Air Products Japan Co., Ltd.] as an antifoaming agent ] 2.5 g was added.

  After mixing them, 1.5 g of a 10 mass% ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a cross-linking agent and stirred for 1 hour. Subsequently, 6 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] was added as a colorant, and the mixture was stirred for 1 hour, and water-dispersed acrylic adhesive An agent composition (8) was obtained. The total light transmittance of the pressure-sensitive adhesive layer having a thickness of 65 μm prepared using the water-dispersed acrylic pressure-sensitive adhesive composition (8) was 19.0%.

(Preparation Example 9)
<Preparation of emulsion>
In a container, 75 g of ion-exchanged water and Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 25% by mass] as a surfactant and Latem PD-104 [Kao Co., Ltd .; active ingredient 20% by mass] 37.5 g was added and dissolved uniformly. Thereto, 235 g of n-butyl acrylate, 235 g of 2-ethylhexyl acrylate, 15 g of methyl methacrylate, 5 g of N-vinylpyrrolidone, 10 g of acrylic acid and 0.2 g of lauryl mercaptan were added and emulsified to obtain 632.7 g of an emulsion.

<Preparation of aqueous dispersion of water-dispersed acrylic copolymer>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 333.5 g of ion-exchanged water was added, and the temperature was raised to 60 ° C. while blowing nitrogen. While stirring, a part of the emulsion prepared above [7.59 g], 2.5 g of ammonium persulfate aqueous solution [6% by mass of active ingredient], 2.5 g of sodium hydrogen sulfite aqueous solution [6% by mass of active ingredient] were added, Polymerization was performed in 1 hour while maintaining 60 ° C. Subsequently, the remaining emulsion (625.11 g) and ammonium persulfate aqueous solution (50 g [active ingredient 1% by mass]) were added dropwise over 6 hours using a separate funnel while keeping the reaction vessel at 60 ° C. After completion of the dropwise addition, the reaction vessel was stirred for 1 hour while maintaining the temperature at 60 ° C. Next, 5 g [active ingredient 2% by mass] of sodium erythorbate aqueous solution was dropped and polymerized over 1 hour using another funnel, and then stirred for 1 hour while maintaining the reaction vessel at 60 ° C. Then, the contents were cooled and adjusted with aqueous ammonia (active ingredient 10% by mass) so that the pH was 7.5. This was filtered through a 200-mesh wire mesh to obtain an aqueous dispersion (2) [solid content concentration of 50% by mass] of an aqueous dispersion type acrylic copolymer. The acrylic copolymer had an average particle size of 338 nm and a weight average molecular weight of 670,000.

<Preparation of water-dispersed acrylic pressure-sensitive adhesive composition>
Superester E-865NT [made by Arakawa Chemical Industries, Ltd .; emulsion-type polymerized rosin ester-based tackifier resin, softening point to 1000 g of aqueous dispersion (2) of the above-mentioned water-dispersed acrylic copolymer; 160 ° C., solid content concentration 50% by mass] 200 g, Surfynol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g as a leveling agent, Surfynol DF-110D [Air Products Japan] as an antifoaming agent Made by Co., Ltd.] 2.5 g was added.

  After mixing them, 1.5 g of a 10 mass% ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a cross-linking agent and stirred for 1 hour. Subsequently, 6 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] was added as a colorant, and the mixture was stirred for 1 hour, and water-dispersed acrylic adhesive An agent composition (9) was obtained. The total light transmittance of the 65 μm thick pressure-sensitive adhesive layer prepared using the obtained water-dispersed acrylic pressure-sensitive adhesive composition (9) was 19.7%.

(Preparation Example 10)
<Preparation of emulsion>
In a container, 75 g of ion-exchanged water and Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 25% by mass] as a surfactant and Latem PD-104 [Kao Co., Ltd .; active ingredient 20% by mass] 37.5 g was added and dissolved uniformly. 229 g of n-butyl acrylate, 229 g of 2-ethylhexyl acrylate, 25 g of methyl methacrylate, 5 g of N-vinylpyrrolidone, 2 g of acrylic acid, 10 g of methacrylic acid and 0.2 g of lauryl mercaptan were added to emulsify, and 632.7 g of the emulsion was obtained. Obtained.

<Preparation of aqueous dispersion of water-dispersed acrylic copolymer>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 333.5 g of ion-exchanged water was added, and the temperature was raised to 60 ° C. while blowing nitrogen. While stirring, a part of the emulsion prepared above [7.59 g], 2.5 g of ammonium persulfate aqueous solution [6% by mass of active ingredient], 2.5 g of sodium hydrogen sulfite aqueous solution [6% by mass of active ingredient] were added, Polymerization was performed in 1 hour while maintaining 60 ° C. Subsequently, the remaining emulsion (625.11 g) and ammonium persulfate aqueous solution (50 g [active ingredient 1% by mass]) were added dropwise over 6 hours using a separate funnel while keeping the reaction vessel at 60 ° C. After completion of the dropwise addition, the reaction vessel was stirred for 1 hour while maintaining the temperature at 60 ° C. Next, 5 g [active ingredient 2% by mass] of sodium erythorbate aqueous solution was dropped and polymerized over 1 hour using another funnel, and then stirred for 1 hour while maintaining the reaction vessel at 60 ° C. Then, the contents were cooled and adjusted with aqueous ammonia (active ingredient 10% by mass) so that the pH was 7.5. This was filtered through a 200-mesh wire mesh to obtain an aqueous dispersion (3) [solid content concentration of 50% by mass] of an aqueous dispersion type acrylic copolymer. The acrylic copolymer had an average particle size of 300 nm and a weight average molecular weight of 630,000.

<Preparation of water-dispersed acrylic pressure-sensitive adhesive composition>
Superester E-865NT [made by Arakawa Chemical Industries, Ltd .; emulsion-type polymerized rosin ester-based tackifier resin, softening point to 1000 g of the aqueous dispersion (3) of the water-dispersed acrylic copolymer described above as a tackifier resin 160 ° C., solid content concentration 50% by mass] 200 g, Surfynol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g as a leveling agent, Surfynol DF-110D [Air Products Japan] as an antifoaming agent Made by Co., Ltd.] 2.5 g was added.

  After mixing them, 1.5 g of a 10 mass% ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a cross-linking agent and stirred for 1 hour. Subsequently, 6 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] was added as a colorant, and the mixture was stirred for 1 hour, and water-dispersed acrylic adhesive An agent composition (10) was obtained. In addition, the total light transmittance of the 65-micrometer-thick adhesive layer prepared using the obtained water-dispersed acrylic adhesive composition (10) was 19.6%.

(Preparation Example 11)
As a crosslinking agent, Z-6040 [manufactured by Toray Dow Corning Co., Ltd., silane-based crosslinking agent, 100% by mass of active ingredient] is added in place of 1.5 g of a 10% ethanol solution of tetrad C. Obtained a water-dispersed acrylic pressure-sensitive adhesive composition (11) in the same manner as in Preparation Example 10. In addition, the total light transmittance of the 65-micrometer-thick adhesive layer prepared using the obtained water dispersion-type acrylic adhesive composition (11) was 19.1%.

(Preparation Example 12)
<Preparation of emulsion>
In a container, 75 g of ion-exchanged water and Aqualon KH-1025 [Daiichi Kogyo Seiyaku Co., Ltd .; active ingredient 25% by mass] as a surfactant and Latem PD-104 [Kao Co., Ltd .; active ingredient 20% by mass] 37.5 g was added and dissolved uniformly. 229 g of n-butyl acrylate, 229 g of 2-ethylhexyl acrylate, 25 g of methyl methacrylate, 5 g of N-vinylpyrrolidone, 2 g of acrylic acid, 10 g of methacrylic acid, 0.3 g of KBE-503 [manufactured by Shin-Etsu Chemical Co., Ltd., 3-methacrylic acid] Roxypropyltriethoxysilane] and 0.2 g of lauryl mercaptan were added and emulsified to obtain 633 g of an emulsion.

<Preparation of aqueous dispersion of water-dispersed acrylic copolymer>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 333.5 g of ion-exchanged water was added, and the temperature was raised to 60 ° C. while blowing nitrogen. While stirring, a part of the emulsion prepared above [7.6 g], an aqueous solution of ammonium persulfate 2.5 g [active ingredient 6% by mass], an aqueous solution of sodium bisulfite 2.5 g [active ingredient 6% by mass] were added, Polymerization was performed in 1 hour while maintaining 60 ° C. Subsequently, the remaining emulsion (625.4 g) and ammonium persulfate aqueous solution (50 g [active ingredient 1% by mass]) were dropped using a separate funnel over 6 hours while maintaining the reaction vessel at 60 ° C. After completion of the dropwise addition, the reaction vessel was stirred for 1 hour while maintaining the temperature at 60 ° C. Next, 5 g [active ingredient 2% by mass] of sodium erythorbate aqueous solution was dropped and polymerized over 1 hour using another funnel, and then stirred for 1 hour while maintaining the reaction vessel at 60 ° C. Then, the contents were cooled and adjusted with aqueous ammonia (active ingredient 10% by mass) so that the pH was 7.5. This was filtered through a 200-mesh wire mesh to obtain an aqueous dispersion (4) [solid content concentration of 50% by mass] of an aqueous dispersion type acrylic copolymer. The average particle diameter of the acrylic copolymer was 360 nm.

<Preparation of water-dispersed acrylic pressure-sensitive adhesive composition>
Superester E-865NT [made by Arakawa Chemical Industries, Ltd .; emulsion-type polymerized rosin ester-based tackifier resin, softening point to 1000 g of the aqueous dispersion (4) of the above-mentioned water-dispersed acrylic copolymer; 160 ° C., solid content concentration 50% by mass] 200 g, Surfinol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g as a leveling agent, Surfynol DF-110D [Air Products Japan] as an antifoaming agent Made by Co., Ltd.] 2.5 g was added.

  After mixing them, 6 g of PSM black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] was added as a colorant, stirred for 1 hour, and water-dispersed. An acrylic pressure-sensitive adhesive composition (12) was obtained. In addition, the total light transmittance of the 65-micrometer-thick adhesive layer prepared using the obtained water-dispersed acrylic adhesive composition (12) was 19.4%.

(Comparative Preparation Example 1)
Superester E-865NT [made by Arakawa Chemical Industries, Ltd .; emulsion-type polymerized rosin ester-based tackifier resin, softening point 160 ° C. to 1000 g of water-dispersed acrylic copolymer (1) 1000 g , Solid content concentration 50% by mass] 200 g, Surfynol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g as a leveling agent, Surfynol DF-110D [Air Products Japan Co., Ltd.] as an antifoaming agent )] 2.5 g was added. After stirring them uniformly, 1.5 g of a 10% by mass ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a crosslinking agent and stirred for 1 hour. This was filtered with a 200 mesh wire mesh to obtain a water-dispersed acrylic pressure-sensitive adhesive composition (H1). In addition, the total light transmittance of the 65-micrometer-thick adhesive layer prepared using the obtained water-dispersed acrylic adhesive composition (H1) was 88.6%.

(Comparative Preparation Example 2)
Superester E-865NT [made by Arakawa Chemical Industries, Ltd .; emulsion-type polymerized rosin ester-based tackifier resin, softening point 160 ° C. to 1000 g of water-dispersed acrylic copolymer (1) 1000 g , Solid content concentration 50% by mass] 200 g, Surfynol PSA-336 [manufactured by Air Products Japan Co., Ltd.] 2.5 g as a leveling agent, Surfynol DF-110D [Air Products Japan Co., Ltd.] as an antifoaming agent )] 2.5 g was added. After stirring them uniformly, 1.5 g of a 10% by mass ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a crosslinking agent and stirred for 1 hour. After filtering this through a 200-mesh wire mesh, 30 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] is added as a colorant, and the mixture is stirred for 1 hour. As a result, a water-dispersed acrylic pressure-sensitive adhesive composition (H2) was obtained. The total light transmittance of the 65 μm thick pressure-sensitive adhesive layer prepared using the obtained water-dispersed acrylic pressure-sensitive adhesive composition (H2) was 0.2%.

(Comparative Preparation Example 3)
1000 g of an aqueous dispersion of an aqueous dispersion type acrylic copolymer (1), 2.5 g of Surfinol PSA-336 [manufactured by Air Products Japan Co., Ltd.] as a leveling agent, and Surfynol DF-110D as an antifoaming agent [Air Products Japan Co., Ltd.] 2.5 g was added. After stirring them uniformly, 1 g of a 10% by mass ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a crosslinking agent and stirred for 1 hour. After filtering this through a 200-mesh wire mesh, 30 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] is added as a colorant, and the mixture is stirred for 1 hour. As a result, a water-dispersed acrylic pressure-sensitive adhesive composition (H3) was obtained. In addition, the total light transmittance of the 65-micrometer-thick adhesive layer prepared using the obtained water-dispersed acrylic adhesive composition (H3) was 0.2%.

(Comparative Preparation Example 4)
1000 g of an aqueous dispersion of an aqueous dispersion type acrylic copolymer (1), 2.5 g of Surfinol PSA-336 [manufactured by Air Products Japan Co., Ltd.] as a leveling agent, and Surfynol DF-110D as an antifoaming agent [Air Products Japan Co., Ltd.] 2.5 g was added. After stirring them uniformly, 1 g of a 10% by mass ethanol solution of Tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy compound] was added as a crosslinking agent and stirred for 1 hour. After filtering this through a 200-mesh wire mesh, 60 g of PSM Black C [manufactured by Mikuni Dye Co., Ltd., carbon black content: 25 mass%, solid content concentration 31 mass%] is added as a colorant, and stirred for 1 hour. As a result, a water-dispersed acrylic pressure-sensitive adhesive composition (H3) was obtained. The total light transmittance of the 65 μm thick pressure-sensitive adhesive layer prepared using the obtained water-dispersed acrylic pressure-sensitive adhesive composition (H4) was 0.0%.

  The formulation table for the above preparation examples is shown in the table below. “Mass%” of the monomer composition in the table represents the amount of each monomer used relative to the total amount of monomer components constituting the acrylic copolymer, and “mass part” of the tackifier resin represents the acrylic copolymer. It represents the mass part of the tackifier resin with respect to 100 parts by mass of the polymer, “mass part” of the crosslinking agent represents the mass part of the crosslinking agent with respect to 100 parts by mass of the acrylic copolymer, and “mass part” of the colorant represents This represents the mass part of carbon black as a colorant with respect to 100 parts by mass of the acrylic copolymer.

Example 1
The water-dispersed acrylic pressure-sensitive adhesive composition (1) obtained in Preparation Example 1 was used as a release liner having a release treatment layer formed using a silicone release agent [manufactured by Sumika Kogyo Co., Ltd., trade name DLS-78WTL] is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on the surface of a release liner by coating the surface so that the thickness after drying is 65 μm and drying at 100 ° C. for 5 minutes. Two sheets were obtained.

Next, the pressure-sensitive adhesive layer possessed by the pressure-sensitive adhesive sheet is formed on both surfaces of the nonwoven fabric substrate (1) dyed with black pigment [manufactured by Nippon Paper Papillia Co., Ltd., trade name: synthetic fiber black, pulp / rayon mixed paper]. The double-sided PSA sheet was obtained by transferring and curing for 3 days in a 40 ° C. environment. The gel fraction of the pressure-sensitive adhesive layer constituting the double-sided pressure-sensitive adhesive sheet after curing was 36.6% by mass. The total light transmittance of the double-sided PSA sheet was 0.1%. Moreover, it was 28.7% when the total light transmittance of the said nonwoven fabric base material (1) was measured by the above-mentioned method, and it was 14 g / m < ² > when the basic weight was measured by the above-mentioned method.

(Example 2)
Example 1 except that instead of the nonwoven fabric substrate (1), a nonwoven fabric substrate (2) dyed with a black pigment [manufactured by Shirakawa Paper Co., Ltd., trade name: thin paper top color, pulp papermaking] was used. A double-sided PSA sheet was obtained in the same manner. Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 0.1%. Moreover, when the total light transmittance of the said nonwoven fabric base material (2) was measured by the above-mentioned method, it was 20.3%, and when the basic weight was measured by the above-mentioned method, it was 14 g / m < ² >.

(Example 3)
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (2) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 1.1%.

Example 4
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 3 except that the nonwoven fabric substrate (2) was used instead of the nonwoven fabric substrate (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive tape was 1.0%.

(Example 5)
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (3) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 2.6%.

(Example 6)
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 5 except that the nonwoven fabric substrate (2) was used instead of the nonwoven fabric substrate (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive tape was 2.5%.

(Example 7)
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (4) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 8.1%.

(Example 8)
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 7, except that the nonwoven fabric substrate (2) was used instead of the nonwoven fabric substrate (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive tape was 7.1%.

Example 9
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (5) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 1.4%.

(Example 10)
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (6) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 1.1%.

(Example 11)
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (7) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 1.3%.

Example 12
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (8) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 1.4%.

(Example 13)
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (9) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 1.3%.

(Example 14)
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (10) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 1.5%.

(Example 15)
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (11) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 1.5%.

(Example 16)
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (12) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 1.5%.

(Example 17)
A double-sided PSA sheet was obtained in the same manner as in Example 3 except that the thickness of the PSA layer was changed from 65 μm to 55 μm. Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 2.0%.

(Example 18)
A double-sided PSA sheet was obtained in the same manner as in Example 3 except that the thickness of the PSA layer was changed from 65 μm to 70 μm. Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 0.3%.

(Comparative Example 1)
Instead of the water-dispersed acrylic pressure-sensitive adhesive composition (1), a water-dispersed acrylic pressure-sensitive adhesive composition (H1) is used, and the nonwoven fabric base material (3) is used instead of the nonwoven fabric base material (1). A double-sided PSA sheet was obtained in the same manner as in Example 1 except that [Dafuku Paper Co., Ltd., pulp / rayon mixed paper] was used. The gel fraction of the pressure-sensitive adhesive layer constituting the double-sided pressure-sensitive adhesive sheet after curing was 30.3% by mass. Moreover, the total light transmittance of the obtained double-sided PSA sheet was 82.5%. Moreover, it was 73.3% when the total light transmittance of the said nonwoven fabric base material (3) was measured by the above-mentioned method, and it was 14 g / m < ² > when the basic weight was measured by the above-mentioned method.

(Comparative Example 2)
A double-sided PSA sheet was obtained in the same manner as in Comparative Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (H2) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (H1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 0.0%.

(Comparative Example 3)
A double-sided PSA sheet was obtained in the same manner as in Comparative Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (H3) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (H1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 0.0%.

(Comparative Example 4)
A double-sided PSA sheet was obtained in the same manner as in Comparative Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (H4) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (H1). Moreover, the total light transmittance of the obtained double-sided pressure-sensitive adhesive sheet was 0.0%.

(Comparative Example 5)
A double-sided PSA sheet was obtained in the same manner as in Comparative Example 1 except that the water-dispersed acrylic pressure-sensitive adhesive composition (4) was used instead of the water-dispersed acrylic pressure-sensitive adhesive composition (H1). Moreover, the total light transmittance of the obtained double-sided PSA sheet was 25.1%.

  The following table shows the results of the above evaluations on the nonwoven fabric substrates used in the examples and comparative examples and the produced double-sided PSA sheet.

  As is clear from the above table, the pressure-sensitive adhesive sheets of the present invention shown in Examples 1 to 16 had good design properties, excellent adhesive strength and holding power, and ensured good peeling resistance. On the other hand, the pressure-sensitive adhesive sheets of Comparative Examples 1 and 5 were poor in design, and the pressure-sensitive adhesive sheets of Comparative Examples 2 to 4 were inferior in constant load holding force and poor in peel resistance.

Claims (9)

A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (B) on one side or both sides of a nonwoven fabric substrate (A) having a total light transmittance of 10% to 35% measured according to JIS K7136, wherein the pressure-sensitive adhesive layer ( B) is a layer formed using a pressure-sensitive adhesive containing the polymer (b1) and one or more colorants (b2) selected from the group consisting of pigments and dyes, wherein the colorant ( b2) is included in the range of 0.1% by mass to 1% by mass with respect to the entire pressure-sensitive adhesive layer (B) , and the pressure-sensitive adhesive layer (B) has an alkyl group having 4 to 8 carbon atoms ( Contains an acrylic copolymer obtained by polymerizing a monomer component containing a (meth) acrylate and a vinyl monomer having a carboxyl group, a pigment, and a tackifying resin having a softening point of 100 to 180 ° C. Formed using an emulsion-type acrylic adhesive A pressure-sensitive adhesive sheet which is a pressure-sensitive adhesive layer and has a total light transmittance of 0.1% to 10% measured according to JIS K7136 of the pressure-sensitive adhesive sheet. The adhesive sheet according to claim 1 basis weight of the nonwoven fabric base material (A) is in the range of ^{5g / m 2 ~25g / m 2} . The pressure sensitive adhesive sheet according to claim 1 or 2 whose total thickness is 200 micrometers or less. The pressure-sensitive adhesive sheet according to claim 1, total light transmittance of 15% to 35% as measured according to JIS K7136 of the nonwoven fabric base material (A). The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer (B) is formed using an emulsion-type acrylic pressure-sensitive adhesive. The pressure sensitive adhesive layer (B) contains a (meth) acrylate having an alkyl group having 4 to 8 carbon atoms, a vinyl monomer having a carboxyl group, and a vinyl monomer having a nitrogen atom. A pressure-sensitive adhesive layer formed by using an emulsion-type acrylic pressure-sensitive adhesive containing an acrylic copolymer obtained by polymerizing a body component, a pigment, and a tackifying resin having a softening point of 100 to 180 ° C. The pressure-sensitive adhesive sheet according to any one of 1 to 5. The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, which is used for fixing a decorative member. The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, which is used for fixing a punching sheet. The speaker obtained by fixing a punching sheet to a housing | casing using the adhesive sheet of Claim 8.