JP2013227408A - Pressure-sensitive adhesivity imparting agent, composition for aqueous pressure-sensitive adhesive agent, aqueous pressure-sensitive adhesive agent, and pressure-sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesivity imparting agent capable of imparting adhesivity such as excellent adhesive power and constant-load retainability to an aqueous pressure-sensitive adhesive agent, and capable of not causing a decrease in adhesive power due to influences of moisture and wet heat and imparting excellent adhesion excellent in wet heat resistance; and to provide a composition for an aqueous pressure-sensitive adhesive agent and an aqueous pressure-sensitive adhesive agent containing the same.SOLUTION: A pressure-sensitive adhesive agent contains a vinyl polymer (A) having a weight-average molecular weight in the range of 500 to 30,000 obtained by polymerizing a monomer (a) having a polymerizable surfactant (a1) and a vinyl monomer (a2) having a nitrogen atom as essential components.

Description

  The present invention relates to a tackifier that can be used in combination with an aqueous pressure-sensitive adhesive.

  Adhesives are used as materials for fixing members in various fields including automobiles, electronic and electrical products, and building materials.

  For example, in the production scene of an automobile, an adhesive is used when an automobile interior member is fixed inside the automobile. Also, in the manufacturing scenes of electronic devices such as mobile phones and liquid crystal displays, fixing cushioning materials installed inside electronic products for the purpose of protecting electronic products from impacts, fixing exterior members of electronic products, liquid crystals An adhesive is used for fixing a member constituting an image display device such as a display device, an organic EL display device, or a PDP.

  As the pressure-sensitive adhesive, from the viewpoint of reducing the environmental load, conversion from a solvent-based pressure-sensitive adhesive to a water-based pressure-sensitive adhesive has been promoted. In recent years, a water-based acrylic pressure-sensitive adhesive in which an acrylic resin or the like is dispersed in an aqueous medium is suitable. It is used.

  In general, the water-based pressure-sensitive adhesive is often used in combination with a tackifier from the viewpoint of further improving the adhesiveness such as adhesive force and constant load holding force.

  Examples of the aqueous pressure-sensitive adhesive containing a tackifier include a tackifier resin emulsion obtained by emulsifying a tackifier resin in the presence of an emulsifier composed of a polymer emulsifier (a) and a nonionic emulsifier (b). An aqueous pressure-sensitive adhesive is known (for example, see Patent Document 1).

  However, the above-mentioned tackifier made of rosin is generally difficult to manufacture and has room for improvement in terms of productivity. In addition, rosin-based tackifiers usually require a large amount of emulsifier in order to stably exist in an aqueous medium, so that the adhesive strength is significantly reduced due to the influence of moisture (water). In some cases, the heat and humidity resistance may be significantly reduced.

JP 2007-126546 A

  The problem to be solved by the present invention is that the adhesive such as excellent adhesive force and constant load holding force can be imparted to the water-based pressure-sensitive adhesive, and the adhesive force is reduced due to the influence of moisture (water) and the influence of wet heat. It is providing the tackifier which can provide the adhesion | attachment excellent in moisture-and-heat resistance, and the composition for aqueous | water-based adhesives and an aqueous | water-based adhesive which contain the same.

  As a result of studying to solve the above-mentioned problems, the present inventors are a tackifier containing a polymerizable surfactant and a vinyl polymer having a specific molecular weight having a structure derived from a vinyl monomer having a nitrogen atom. The present inventors have found that the above-mentioned problems can be solved.

  That is, the present invention provides a weight average molecular weight of 500 to 30, obtained by polymerizing the polymerizable surfactant (a1) and the monomer (a) containing the vinyl monomer (a2) having a nitrogen atom as essential components. The present invention relates to a tackifier containing a vinyl polymer (A) in the range of 000, an aqueous pressure-sensitive adhesive composition containing the same, and an aqueous pressure-sensitive adhesive.

  With the tackifier of the present invention, excellent adhesiveness (especially, constant load holding force to a difficult-to-adhere substrate) can be imparted to an aqueous adhesive, and can be achieved with a conventional aqueous adhesive. It is possible to give excellent moisture and heat resistance without causing the influence of moisture (water) and the decrease in adhesive strength due to the influence of moisture and heat. In addition to fixing materials and door trims, cushioning agents, sealing agents, fixing of cushioning materials installed inside electronic products for the purpose of protecting electronic devices such as mobile phones and liquid crystal displays from impacts, It can be used for fixing an exterior member, and also for an adhesive sheet or the like when manufacturing furniture or the like.

  In particular, the tackifier of the present invention has a level that does not cause peeling or the like over time regardless of the influence of moisture or the like even when the aqueous adhesive is applied to the surface of a relatively hydrophilic substrate. It is possible to impart an adhesive force.

  The polymerizable surfactant (a1) is an essential component for imparting wet heat resistance, and has a polymerizable group, preferably a vinyl group, because it is incorporated in the skeleton of the tackifier of the present invention. Is preferably used. Examples of the polymerizable surfactant (a1) include alkyl allyl sulfosuccinic acid ammonium salt, alkyl allyl sulfosuccinic acid sodium salt, polyoxyethylene nonylpropenyl phenyl ether sulfate ammonium salt, polyoxyethylene-1- (allyloxymethyl). ) Alkyl sulfate ammonium salt, polyoxyalkylene alkenyl ether sulfate ammonium salt, α-sulfo-ω- (1- (nonylphenoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2 -Ethanediyl) ammonium salt, α-sulfo-ω- (1- (alkoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethanediyl) ammonium salt, di (alkyl methacrylate) Foss Sodium sulfate, bis (polyoxyethylene polycyclic phenyl ether) methacrylate sulfate, alkoxy polyethylene glycol maleate, polyoxyalkylene alkenyl ether, 2-sodium sulfoalkyl methacrylate, etc. Can be used.

  The polymerizable surfactant (a1) specifically includes “Latemul S-180”, “S-180A”, “PD-104” [Kao] containing compounds having a polyoxyethylene structure and a sulfate ester structure. "RS-3000" (manufactured by Sanyo Kasei Kogyo Co., Ltd.), "Aquaron HS-5" "HS-10" "BC-5" "BC-20" "KH-05" "KH-10" “KH-1025” (Daiichi Kogyo Seiyaku Co., Ltd.), “ADEKA rear soap SE-10” “SE-20” “SR-10” “SR-1025” “SR-20” “SR-30” “SR” -3025 "(manufactured by Asahi Denka Kogyo Co., Ltd.)," Antox MS-60 "(manufactured by Nippon Emulsifier Co., Ltd.), etc .;" Eleminol JS-20 "(manufactured by Sanyo Chemical Industries, Ltd.) having a sulfate ester structure, Antto "MS-2N" (manufactured by Nippon Emulsifier Co., Ltd.); "New Frontier A-229E" (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) having a phosphate group, and the like; including a compound having a polyoxyethylene structure and a carboxylic acid group. Antox EMH-20, LMH-20, SMH-20 (manufactured by Nippon Emulsifier Co., Ltd.) and the like can be used, and “AQUALON RN-10” and “RN-20” include compounds having a nonionic hydrophilic group. "RN-30" "RN-50" (Daiichi Kogyo Seiyaku Co., Ltd.), "Latemul PD-420" "PD-430" "PD-450" [Kao Corporation], "Adekaria Soap ER-" 10 "" ER-20 "" ER-30 "" ER-40 "[Asahi Denka Kogyo Co., Ltd.] etc. can be used. These polymerizable surfactants may be used alone or in combination of two or more.

  Further, as the polymerizable surfactant (a1), for example, a cationic polymerizable surfactant as shown in the following chemical formula (1) can be used. When the cationic polymerizable surfactant is used, a nonionic group-containing acrylic resin or a cationic group-containing acrylic resin can be used as the acrylic resin (C) described later.

  Among the above-mentioned polymerizable surfactants (a1), it is preferable to use those having a polyoxyethylene structure or a sulfate ester structure as the hydrophilic part, from the viewpoint of imparting excellent moisture and heat resistance. Moreover, as said polymeric surfactant (a1), it is dispersion stability in the aqueous medium (B) of a vinyl polymer (A) to use what has a weight average molecular weight of the range of 150-5,000. It is preferable for improving the heat resistance and further improving the heat-and-moisture resistance of the pressure-sensitive adhesive.

  As the usage-amount of the said polymeric surfactant (a1), it is used in the range of 0.1 mass%-5 mass% with respect to the said monomer (a) whole quantity from a viewpoint which can improve heat resistance more. Is preferable, and the range of 0.1% by mass to 3% by mass is more preferable.

  The vinyl monomer (a2) having a nitrogen atom is an essential component for imparting a constant load retention force to a particularly excellent difficult-to-adhere substrate. For example, (meth) acrylamide, N-methyl (meta) ) Acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-methylol (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N, N-dimethyl (meth) ) Amides such as acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, diacetone (meth) acrylamide, and hydroxyethyl (meth) acrylamide Group-containing monomers, N-vinylpyrrolidone, N- Monomers having a lactam ring such as nilcaprolactam and acryloylmorpholine, monomers having a maleimide group such as maleimide and cyclohexylmaleimide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) Cationized monomers having amino groups such as acrylate, N, N-dimethylaminoethyl (meth) acrylate methyl chloride quaternary salt, N, N-dimethylaminopropyl (meth) acrylate methyl chloride quaternary salt, etc. A monomer having an amino group, a monomer having a thiano group such as acrylonitrile, and the like can be used. These vinyl monomers may be used alone or in combination of two or more.

  Among these, from the viewpoint of further improving the adhesion such as a constant load holding force to a difficult-to-adhere substrate, it is preferable to use a monomer having an amide group or a lactam ring, and further a viewpoint of improving production stability. Therefore, it is preferable to use a monomer having an amide group, and it is more preferable to use (meth) acrylamide, N-methyl (meth) acrylamide, or N, N-dimethyl (meth) acrylamide.

  As a usage-amount of the vinyl monomer (a2) which has the said nitrogen atom, from a viewpoint which can improve adhesiveness, such as a constant load holding power to a hard-to-bond base material, with respect to the said monomer (a) whole quantity. , Preferably 0.1 to 5% by mass, more preferably 0.1 to 3% by mass.

  The monomer (a) forming the vinyl polymer (A) includes the polymerizable surfactant (a1) and a vinyl monomer (a2) having a nitrogen atom as essential components. It is preferable to contain other vinyl monomer (a3) in order to further improve wet heat resistance.

  Examples of the other vinyl monomer (a3) include methyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and tert- (meth) acrylate. (Meth) acrylic acid alkyl esters such as butyl, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, cyclohexyl (meth) acrylate, and carboxyl groups such as (meth) acrylic acid , Vinyl monomers having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, aminoethyl (meth) acrylate, N-monoalkylaminoalkyl (meth) acrylate, (meth) acrylic Acid N, N-dialkylaminoalkyl, (meth) acrylamide, isopropyl acrylic Vinyl esters such as amide, acrolein, diacetone (meth) acrylamide, vinyl acetate, vinyl propionate, vinyl versatic acid; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, amyl vinyl ether, hexyl vinyl ether; ) Vinyl nitriles such as acrylonitrile; vinyl monomers having an aromatic ring such as styrene, α-methylstyrene, vinyl toluene, vinyl anisole, α-halostyrene, vinyl naphthalene; functional groups such as isoprene, butadiene, ethylene No vinyl monomers; heterocyclic vinyl monomers such as vinyl pyrrolidone, crosslinkability such as glycidyl (meth) acrylate, γ- (meth) acryloxypropyltriethoxysilane Functional group can be used vinyl monomers having a. These vinyl monomers may be used alone or in combination of two or more. In addition, the description of “(meth) acrylic acid” in the present invention indicates one or both of acrylic acid and methacrylic acid.

  Among these, as the other vinyl monomer (a3), it is preferable to use (meth) acrylic acid alkyl ester, and (meth) acrylic acid cyclohexyl, (meth) acrylic acid dicyclopentanyl, ( The use of a (meth) acrylic acid alkyl ester having an alicyclic structure such as (meth) acrylic acid adamantyl or (meth) acrylic acid isobornyl is even more preferable in terms of imparting even better moisture and heat resistance to the aqueous pressure-sensitive adhesive.

  The other vinyl monomer (a3), preferably a (meth) acrylic acid alkyl ester, more preferably a (meth) acrylic acid alkyl ester having an alicyclic structure, is based on the total amount of the monomer (a). It is preferably used in the range of 50% by mass to 99% by mass, and more preferably in the range of 70% by mass to 99% by mass.

  The vinyl polymer (A) includes, for example, the polymerizable surfactant (a1), the vinyl monomer (a2) having a nitrogen atom, and preferably the other vinyl monomer (a3). It can be produced by emulsion polymerization in the presence of a polymerization initiator, an aqueous medium (B) and, if necessary, an external surfactant.

  In the emulsion polymerization method, in the aqueous medium (B), the polymerizable surfactant (a1), the vinyl monomer (a2) having a nitrogen atom, and preferably the other vinyl monomer (a3) In a temperature range of about 0 ° C. to 200 ° C. for about 1 hour to 10 hours, and preferably, the polymerizable surfactant (a1) and the vinyl monomer (a2) having a nitrogen atom, This is a method of radical polymerization of the other vinyl monomer (a3).

  As a weight average molecular weight of the said vinyl polymer (A), it is essential that it is the range of 500-30,000. When the vinyl polymer having a weight average molecular weight of 35,000 is used instead of the vinyl polymer (A), the compatibility with the acrylic resin (C) or the like is lowered, and as a result, the water-based pressure-sensitive adhesive is used. In some cases, it is not possible to provide adhesion such as excellent constant load holding force.

  As a weight average molecular weight of the said vinyl polymer (A), the range of 500-10,000 is preferable and the range of 3,000-9,000 is more preferable from a viewpoint which provides the further outstanding adhesiveness. The weight average molecular weight was measured by the gel permeation chromatography (GPC) method under the following conditions.

Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4 mass%)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-380" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-450" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-850" manufactured by Tosoh Corporation

  Examples of the method for adjusting the weight average molecular weight of the vinyl polymer (A) in the range of 500 to 30,000 include a method using a chain transfer agent, a method using a large amount of a polymerization initiator, and a polymerization temperature of about 100 ° C. The method performed by the above is mentioned. It is possible to adopt a method for producing a vinyl polymer (A) having a predetermined weight average molecular weight by adjusting the polymerization temperature to approximately 100 ° C. or higher to perform odor caused by the chain transfer agent or the polymerization initiator. And is preferable in reducing VOC.

  Examples of the polymerization initiator include redox-based initiators such as azo initiators, persulfate-based initiators, peroxide-based initiators, persulfate-reducing agents, peroxide-reducing agents, and iron-peroxides. An agent or the like can be used.

  Examples of the azo initiator include 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl). ) Propane] disulfate, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2- (5-methyl-2) -Imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (N, N′-dimethyleneisobutylamidine), and the like as persulfate-based initiators, for example, potassium persulfate, sodium persulfate Examples of peroxide initiators such as ammonium persulfate include benzoyl peroxide, t-butyl hydroperoxide, and hydrogen peroxide. Examples of reducing agents include sodium ascorbate and erythro Sodium bottles acid, sodium metabisulfite and the like, as the iron, for example, ferric hydrochloric acid can be exemplified. These may be used alone or in combination of two or more. Especially, as a polymerization initiator, it is preferable to use hydrogen peroxide from a viewpoint of maintaining the outstanding heat-and-moisture resistance.

  The amount of the initiator used varies depending on the reaction temperature and type, but is generally 0.01% by mass to 5% by mass, preferably 0.005% by mass with respect to the total amount of the monomer (a). % To 1% by mass, more preferably 0.02% to 0.5% by mass.

  Moreover, when manufacturing the said vinyl polymer (A), a chain transfer agent can be used as needed. Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, α-pinene, β-pinene, D-limonene, terpinolene, α-methyl. Styrene dimer etc. can be used individually or in combination of 2 or more types.

  The amount of the chain transfer agent used is generally preferably 0.001% by mass to 5% by mass and more preferably 0% by mass with respect to the total amount of the monomer (a). .

  Moreover, when manufacturing the said vinyl polymer (A), an external surfactant can be used as needed.

  The external surfactant is used when the mass ratio derived from the polymerizable surfactant in the vinyl polymer (A) contained in the tackifier of the present invention is about 0.5% by mass or less, or the vinyl polymer. When the production of (A) is carried out under high temperature conditions of approximately 90 ° C. or higher, or when the average particle diameter of the vinyl polymer (A) is approximately 500 nm or more, aggregation of the vinyl polymer (A) is prevented. It is preferable to use for this purpose.

  As the external surfactant, for example, an anionic surfactant, a nonionic surfactant, a cationic surfactant, an amphoteric surfactant and the like can be used. Among these, it is preferable to use an anionic surfactant in order to improve the mechanical stability of the pressure-sensitive adhesive.

  As the anionic surfactant, for example, a higher alcohol sulfate, alkylbenzene sulfonate, polyoxyethylene alkylphenyl sulfonate, or the like can be used alone or in combination of two or more.

  The amount of the external surfactant used varies depending on the type of the surfactant and the like, but is preferably used in the range of 0.01% by mass to 2% by mass with respect to the mass of the vinyl polymer (A). It is preferable to use in the range of 0.01 mass% to 1 mass%.

  As the vinyl polymer (A), those having a glass transition temperature of 30 ° C. to 300 ° C. are preferably used, and those having a glass transition temperature of 50 ° C. to 200 ° C. impart excellent moisture and heat resistance to the aqueous adhesive. This is preferable because it is possible. In addition, the said glass transition temperature points out the midpoint glass transition temperature measured using the differential scanning calorimeter (DSC). The glass transition temperature of a vinyl polymer having a weight average molecular weight of approximately 30,000 or more generally coincides with the calculated glass transition temperature derived by the FOX equation. However, the glass transition temperature of a vinyl polymer having a relatively small weight average molecular weight such as the vinyl polymer (A) deviates from the calculated glass transition temperature calculated by the FOX equation as the weight average molecular weight decreases. There is a tendency. Therefore, the calculated glass transition temperature may not be able to properly indicate the original glass transition temperature of the vinyl polymer.

  As the vinyl polymer (A), those having a softening point of 50 ° C. to 300 ° C. are preferably used, and those having a softening point of 70 ° C. to 300 ° C. impart excellent moisture and heat resistance to the aqueous adhesive. This is preferable because it is possible. The softening point is a value measured by the ring and ball method (JIS K5902).

  As the vinyl polymer (A), it is preferable to use a polymer having an average particle diameter of 50 nm to 500 nm, more preferably in the range of 100 nm to 300 nm, from the viewpoint of imparting excellent heat and moisture resistance. Here, the average particle diameter refers to a value measured by a dynamic light scattering method.

  The vinyl polymer (A) obtained by the above method may not contain a solvent such as water, but from the viewpoint of ease of mixing with an aqueous pressure-sensitive adhesive, It is preferable that they are mixed. The vinyl polymer (A) is preferably contained in the range of 0.1 to 75% by mass, preferably 1 to 65% by mass, based on the total amount of the tackifier.

  Next, the aqueous medium (B) used in the present invention will be described.

  As the aqueous medium (B), water, a hydrophilic organic solvent miscible with water, and a mixture thereof can be used. Examples of the hydrophilic organic solvent include alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol and propylene glycol; alkyls of polyalkylene glycol Ethers; those generally known as high-boiling solvents such as lactams such as N-methyl-2-pyrrolidone can be used. 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.

  The aqueous medium (B) is preferably contained in an amount of 25 mass% to 99.9 mass%, more preferably 35 mass% to 99 mass%, based on the total amount of the tackifier of the present invention.

  The tackifier of the present invention can be used as a composition for aqueous adhesives by combining with, for example, an aqueous dispersion of an acrylic resin, which is a base resin of an aqueous adhesive.

  As the aqueous dispersion of the acrylic resin which is the base resin of the aqueous pressure-sensitive adhesive, a dispersion in which an acrylic resin is dispersed in the aqueous medium (B) can be used, and in particular, a glass transition temperature of −10 ° C. or less and a weight average molecular weight. It is preferable to use an acrylic resin (C) that is 100,000 or more dispersed in the aqueous medium (B) in order to further improve the performance (adhesive 3 physical properties) as an adhesive.

  As said acrylic resin (C), various acrylic resin (C) conventionally used as an adhesive component can be used, for example.

  As said acrylic resin (C), Preferably what has a weight average molecular weight of the range of preferably 100,000 or more, more preferably 300,000-2 million can be used, and the thing of 500,000-1 million is used. It is particularly preferable for imparting excellent adhesion and holding force to the adherend. In addition, the weight average molecular weight of the said acrylic resin points out the value obtained similarly to the said vinyl polymer (A).

  As said acrylic resin (C), Preferably what has a glass transition temperature of -10 degreeC or more, More preferably, -10 degreeC--70 degreeC can be used, The thing of -30 degreeC--70 degreeC is used. It is particularly preferable for imparting excellent adhesion to the adherend. In addition, the said glass transition temperature points out the midpoint glass transition temperature measured using the differential scanning calorimeter (DSC).

  As said acrylic resin (C), it is preferable to use what has an average particle diameter of 50 nm-500 nm from a viewpoint which provides the outstanding adhesive force with respect to a to-be-adhered body, especially the outstanding anchoring property, and 100 nm-300 nm. The range of is more preferable. Here, the average particle diameter refers to a value measured by a dynamic light scattering method.

  Moreover, as said acrylic resin (C), the acrylic resin which has hydrophilic groups, such as an anionic group, can be used from a viewpoint of disperse | distributing stably in an aqueous medium.

  As the anionic group, for example, a carboxyl group, a sulfonyl group, a carboxylate group or a sulfonate group in which they are neutralized with a basic compound can be used.

  Examples of the basic compound include alkali metal compounds such as sodium hydroxide and potassium hydroxide, alkaline earth metal compounds such as calcium hydroxide and calcium carbonate, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, Water-soluble organic amines such as monopropylamine, dimethylpropylamine, monoethanolamine, diethanolamine, dimethylethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, ammonia, etc., and one or a mixture of two or more of these Can be used. Among these, when it is desired to improve the obtained coating, it is preferable to use ammonia that is scattered at room temperature or by heating.

  As said acrylic resin (C), it is preferable to use the linear acrylic resin which does not have a branched structure as much as possible from a viewpoint of providing the adhesive force outstanding with respect to the to-be-adhered body.

  As the acrylic resin (C), specifically, those obtained by radical polymerization of a vinyl monomer described later can be used.

  As said vinyl monomer, (meth) acrylic-acid alkylester, the vinyl monomer which has a carboxyl group, the vinyl monomer which has a hydroxyl group etc. can be used, for example.

  Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) Examples include tert-butyl acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like. Among them, the use of one or more selected from the group consisting of 2-ethylhexyl acrylate, butyl acrylate, octyl acrylate and nonyl acrylate can lower the glass transition temperature of the resulting vinyl resin (A), As a result, it is preferable because it can give excellent adhesion to a porous body or an adherend with low surface polarity and water-resistant adhesion. On the other hand, by using cyclohexyl (meth) acrylate, methyl (meth) acrylate, ethyl acrylate, etc. as the (meth) acrylic acid acrylic ester, the adhesive such as heat-resistant adhesive force and adhesive retention force excellent in aqueous adhesives It is also possible to give performance.

  Examples of the vinyl monomer having a carboxyl group that can be used for the production of the acrylic resin (C) include (meth) acrylic acid, β-carboxyethyl (meth) acrylate, and 2- (meth) acryloyl. Propionic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, itaconic acid half ester, maleic acid half ester, maleic anhydride, itaconic anhydride, β- (meth) acryloyloxyethyl hydrogen succinate, β- (meth) Hydroxyethyl hydrogen phthalate and salts thereof can be used alone or in combination of two or more. Especially, it is preferable to use (meth) acrylic acid as a vinyl monomer which has the said carboxyl group.

  By using the vinyl monomer having a carboxyl group, a carboxyl group or a carboxylate group can be introduced into the acrylic resin (C). Such a carboxyl group reacts with a functional group of the crosslinking agent when, for example, an epoxy crosslinking agent, an oxazoline crosslinking agent, a carbodiimide crosslinking agent, a silane crosslinking agent, or the like is used in combination. Thereby, the adhesion layer excellent in adhesion performance, such as heat-resistant adhesive force and adhesion retention force, can be formed. In addition, by introducing the carboxyl group or the like, good water dispersion stability can be imparted to the acrylic resin (C).

  Examples of the vinyl monomer having a hydroxyl group that can be used for the production of the acrylic resin (C) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono ( (Meth) acrylate, glycerol mono (meth) acrylate, and the like can be used.

  By using the vinyl monomer having a hydroxyl group, a hydroxyl group can be introduced into the acrylic resin (C). Such a hydroxyl group reacts with an isocyanate group of the crosslinking agent when, for example, a polyisocyanate crosslinking agent is used in combination. Thereby, the adhesion layer excellent in adhesion performance, such as heat-resistant adhesive force and adhesion retention strength retention force, can be formed.

  As the vinyl monomer used for the production of the acrylic resin (C), other vinyl monomers can be used as required in addition to the above-described ones.

  Examples of other vinyl monomers include aminoethyl (meth) acrylate, N-monoalkylaminoalkyl (meth) acrylate, N, N-dialkylaminoalkyl (meth) acrylate, (meth) acrylamide, and isopropylacrylamide. , Vinyl esters such as acrolein, diacetone (meth) acrylamide, vinyl acetate, vinyl propionate, vinyl versatic acid; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, amyl vinyl ether, hexyl vinyl ether; (meth) Vinyl nitriles such as acrylonitrile; vinyls having aromatic rings such as styrene, α-methylstyrene, vinyltoluene, vinylanisole, α-halostyrene, vinylnaphthalene Nyl monomers; vinyl monomers having no functional group such as isoprene, butadiene, and ethylene; heterocyclic vinyl monomers such as vinyl pyrrolidone, and the like can also be used.

  As the acrylic resin (C) used in the present invention, the (meth) acrylic acid alkyl ester is 45% by mass to 99% by mass and the carboxyl group-containing vinyl simple substance with respect to the total amount of the mixture composed of the vinyl monomer. It is preferable to use a polymer obtained by polymerizing a vinyl monomer mixture containing 0.5% by mass to 5% by mass of a monomer, 70% to 99% by mass of the (meth) acrylic acid alkyl ester, and The use of a polymer obtained by polymerizing a vinyl monomer mixture containing 0.5% by mass to 5% by mass of a carboxyl group-containing vinyl monomer provides excellent adhesion to the adherend and water-resistant adhesion. It is more preferable for obtaining the aqueous adhesive provided.

  The acrylic resin (C) can be produced, for example, by subjecting the vinyl monomer to emulsion polymerization in the presence of a polymerization initiator, an aqueous medium (B) and, if necessary, a surfactant.

  The emulsion polymerization is preferably carried out in a temperature range of about 0 ° C. to 80 ° C. for about 3 hours to 10 hours, and radical polymerization of the vinyl monomer is carried out by an emulsion polymerization method.

  Examples of the surfactant that can be used in the production of the acrylic resin (C) include an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant. Can be used. Among these, an anionic surfactant is preferably used in order to improve the mechanical stability of the pressure-sensitive adhesive. As said surfactant, the thing similar to what was illustrated as what can be used when manufacturing the said vinyl polymer (A) can be used.

  The aqueous pressure-sensitive adhesive composition of the present invention may contain other additives as required in addition to the above-described components.

  Examples of the additive include powders such as a crosslinking agent, a crosslinking catalyst, a colorant, and a pigment, a surfactant, a plasticizer, a tackifier, a low molecular weight polymer, a surface smoothing agent, a leveling agent, an antioxidant, and corrosion. Inhibitors, light stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particles, foils, etc. can be added as appropriate according to the intended use. .

The said crosslinking agent can provide moderate adhesive force to an adhesive for aqueous | water-based adhesive composition.
When using a crosslinking agent, it is preferable to use as the acrylic resin (C) or the like a functional group capable of reacting with the crosslinking agent, specifically, one having the above-described hydroxyl group or carboxyl group.

  Examples of the crosslinking agent include tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI), polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate, polyether polyisocyanate, polyester polyisocyanate, trimethylolpropane / tolylene diisocyanate trimer. Isocyanate crosslinking agents such as adducts, epoxy crosslinking agents such as polyethylene glycol diglycidyl ether, polyfunctional melamine compounds such as methylated trimethylol melamine and butylated hexamethylol melamine, oxazoline crosslinking agents, carbodiimide crosslinking agents, silane crosslinking agents, An externally added crosslinking agent such as an aziridine crosslinking agent or an organometallic crosslinking agent can be used. Especially, it is preferable to use an epoxy crosslinking agent, an oxazoline crosslinking agent, a silane crosslinking agent, and an isocyanate crosslinking agent. As the isocyanate crosslinking agent, an aliphatic isocyanate crosslinking agent is preferably used from the viewpoint of improving yellowing resistance.

  Although the usage-amount of the said crosslinking agent is not restrict | limited in particular, For example, 0.01 mass%-5 mass% are preferable normally with respect to the whole quantity of an acrylic resin (C), 0.01 mass%-3 mass% A range is more preferable.

  The aqueous adhesive composition of the present invention can be produced, for example, by mixing a tackifier previously produced by the above method with an aqueous dispersion of the acrylic resin (C) produced by the above method.

  The composition for aqueous adhesives of the present invention obtained by the above method can be used exclusively for aqueous adhesives.

  The aqueous pressure-sensitive adhesive can be used, for example, for producing a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on one side or both sides of a support. Moreover, it can also be used for manufacture of the adhesive sheet which consists only of the adhesion layer which does not have a support body.

  The pressure-sensitive adhesive sheet can be produced, for example, by applying the aqueous pressure-sensitive adhesive on one or both sides of a support, and drying and removing the aqueous medium (B).

  The aqueous pressure-sensitive adhesive can be applied using, for example, a roll coater, gravure coater, reverse coater, lip coater, spray coater, air knife coater, die coater or the like.

  In addition, when sticking a release film on the pressure-sensitive adhesive sheet, a method of sticking a release film on the surface of the pressure-sensitive adhesive sheet obtained by the method, or applying the aqueous pressure-sensitive adhesive on the release film, The method of sticking a support body to the adhesive layer surface after removing an aqueous medium (B) etc. is mentioned.

  The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is 10% by mass to 90% by mass by appropriately selecting the type and amount of functional groups contained in the aqueous pressure-sensitive adhesive to be used, the polymerization conditions, and the type and amount of crosslinking agent. It is preferable to adjust so that. In particular, in order to achieve both adhesiveness to difficult-to-bond surfaces such as rough surfaces and low-polar adherends, adhesiveness that can withstand the repulsive force and dimensional change of the member to be applied, and cohesive strength at high temperatures, The fraction is more preferably 30% by mass to 50% by mass.

In the present specification, the gel fraction means the content of the gel component, for example, the mass of the adhesive layer dipped in a good solvent such as tetrahydrofuran, ethyl acetate, toluene and then dried. It can obtain | require by measuring ratio with the mass of the adhesion layer before immersion.
The gel fraction can be adjusted by using a branching by a hydrogen abstraction by an initiator or a crosslinking agent during the polymerization of the acrylic resin (C). The crosslinking agent can be used during the polymerization of the acrylic resin (C), or may be used after mixing the acrylic resin (C) and the tackifier.
As the crosslinking method, conventionally known methods such as thermal crosslinking and photocrosslinking can be used. The cohesive force as the pressure-sensitive adhesive can be further increased by the crosslinking agent.

  As the support, a foam, a film, a nonwoven fabric, paper, or the like can be used.

  As the material of the foam, urethane, EPDM, polyethylene or the like can be used. As the material of the film, polyethylene terephthalate, polyethylene naphthalate, polypropylene, polyethylene, polystyrene, ABS, polycarbonate, polyimide, polyvinyl chloride, nylon, polyvinyl alcohol, cellophane, and the like can be used. As the material of the nonwoven fabric, cotton, hemp, pulp, rayon, acetate fiber, polyester fiber, polyvinyl alcohol fiber, polyamide fiber, etc., and a mixture thereof can be used. Furthermore, you may perform the impregnation process which used the viscose impregnation and the thermoplastic resin as a binder as needed.

  If it is an aqueous pressure-sensitive adhesive containing the tackifier of the present invention, excellent adhesion is maintained regardless of the influence of moisture or the like, even when applied to a surface that is relatively hydrophilic as the support. Is possible.

  The surface of the support may be subjected to an easy adhesion surface treatment by corona treatment or the like in advance from the viewpoint of improving the adhesion with the adhesive layer.

  Examples of the method of applying the aqueous pressure-sensitive adhesive to the surface of the support include methods using a roll coater, gravure coater, reverse coater, lip coater, spray coater, air knife coater, die coater and the like.

  The thickness of the pressure-sensitive adhesive layer formed on the surface of the support is not particularly limited, but is preferably in the range of 1 μm to 200 μm, and more preferably in the range of 15 μm to 70 μm.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

<< Synthesis Example 1 >> (Synthesis Example of Acrylic Resin (C-1))
Lateoxyl PD-104 (manufactured by Kao Corporation, the addition mole number of oxyethylene is 15 moles, and the addition mole number of oxybutylene is 6 moles in a container equipped with a stirrer. -Polyoxyalkylene alkenyl ether sulfate ammonium salt having a polyoxybutylene structure and a sulfate ester structure, 5 parts by mass of a polymerizable surfactant, nonvolatile content 20% by mass and Aqualon KH-1025 (Daiichi Kogyo Seiyaku) A polymerizable surfactant which is a polyoxyethylene-1- (allyloxymethyl) alkylsulfuric acid ammonium salt having a polyoxyethylene structure in which the number of moles of oxyethylene added is 10 mol and a sulfate ester structure , Non-volatile content 20% by mass) 5.6 parts by mass, 2-ethyl acrylate Charge 45.5 parts by mass of sill, 45.5 parts by mass of butyl acrylate, 5 parts by mass of methyl methacrylate, 1.5 parts by mass of N-vinylpyrrolidone and 2.5 parts by mass of acrylic acid, and stir. To prepare an emulsion.

  The inside of the polymerization vessel equipped with a thermometer, a dropping device, a reflux condenser, and a stirring device was replaced with nitrogen gas, 55.5 parts by mass of ion-exchanged water was charged, and the internal temperature was raised to 60 ° C. while stirring.

  In the polymerization vessel, an emulsion of 1% by mass with respect to the total amount of the emulsion was charged, and then 1 part by mass of sodium pyrosulfite aqueous solution (nonvolatile content 3% by mass) and ammonium persulfate aqueous solution (nonvolatile content 3). 1% by mass) was added to initiate polymerization.

  After holding for 30 minutes, the remaining emulsion (99% by mass) and 10 parts by mass of an aqueous ammonium persulfate solution (nonvolatile content 1% by mass) were dropped into the polymerization vessel over 6 hours to carry out polymerization.

  After completion of the dropping, the polymerization vessel is held at an internal temperature of 60 ° C. for 1 hour, and then the polymerization vessel is cooled to about 25 ° C., and then the content is filtered through a 200 mesh filter cloth (polyester) to obtain a nonvolatile content of 51 An aqueous dispersion of acrylic resin (C-1) having 0.5 mass%, a particle size of 320 nm, and a weight average molecular weight of 800,000 was obtained.

  The glass transition temperature (midpoint glass transition temperature) measured with a differential scanning calorimeter (DSC, manufactured by TA Instruments Co., Ltd.) of the previous acrylic resin (C-1) was -43 ° C. Hereinafter, in this invention, it measured by the same method.

  The weight average molecular weight is HLC-8220 (GPC manufactured by Tosoh Corporation), 4 columns of “TSKgel GMHXL” (manufactured by Tosoh Corporation) are used in series, and tetrahydrofuran is used as a mobile phase solvent. The flow rate was adjusted to 1 ml / min, and the measurement was performed using a tetrahydrofuran solution of acrylic resin (nonvolatile content: 0.4% by mass) as a sample.

<< Example 1 >> Tackifier (1)
Lateoxyl PD-104 (manufactured by Kao Corporation, the addition mole number of oxyethylene is 15 moles, and the addition mole number of oxybutylene is 6 moles in a container equipped with a stirrer. -Polyoxyalkylene alkenyl ether sulfate ammonium salt having a polyoxybutylene structure and a sulfate ester structure, a polymerizable surfactant (non-volatile content 20% by mass) 2.5 parts by weight as a non-polymerizable surfactant 1.1 parts by mass of Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd., sodium dodecylbenzenesulfonate, 63% by mass of non-volatile content), 98 parts by mass of cyclohexyl methacrylate, 2 parts by mass of methacrylamide, As a transfer agent, 2.2 parts by mass of lauryl mercaptan and 25 parts by mass of ion-exchanged water were added and stirred. By was adjusted emulsion.

  The inside of the polymerization vessel equipped with a thermometer, a dripping device, a reflux condenser and a stirring device is replaced with nitrogen gas, and 12.5 parts by mass of the Latem PD-104 as a non-polymerizable surfactant as a polymerizable surfactant 0.8 parts by mass of Neogen SC-F and 167.5 parts by mass of ion-exchanged water were charged, and the temperature inside the container was raised to 130 ° C. while stirring.

  Into the polymerization vessel, 10.2 parts by mass of aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass) was charged and held for 15 minutes, and then the emulsion and aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass). 30.5 parts by mass were dropped into the polymerization vessel over 3 hours.

  After completion of the dropwise addition, the polymerization vessel is maintained at an internal temperature of 130 ° C. for 1 hour, and then the polymerization vessel is cooled to about 25 ° C., and then the content is filtered through a 200 mesh filter cloth (polyester) to obtain a non-volatile content of 30. A tackifier (1) containing a vinyl polymer (1) having a mass%, a particle diameter of 101 nm, and a weight average molecular weight of 5000 was obtained.

<< Example 2 >> Tackifier (2)
Lateoxyl PD-104 (manufactured by Kao Corporation, the addition mole number of oxyethylene is 15 moles, and the addition mole number of oxybutylene is 6 moles in a container equipped with a stirrer. -Polyoxyalkylene alkenyl ether sulfate ammonium salt having a polyoxybutylene structure and a sulfate ester structure, a polymerizable surfactant (non-volatile content 20% by mass) 2.5 parts by weight as a non-polymerizable surfactant Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd., sodium dodecylbenzenesulfonate, nonvolatile content 63% by mass), 1.1 parts by mass, 95 parts by mass of cyclohexyl methacrylate, 5 parts by mass of methacrylamide, As a transfer agent, 4.0 parts by mass of lauryl mercaptan and 25 parts by mass of ion-exchanged water were added and stirred. By was adjusted emulsion.

  The inside of the polymerization vessel equipped with a thermometer, a dripping device, a reflux condenser and a stirring device is replaced with nitrogen gas, and 12.5 parts by mass of the Latem PD-104 as a non-polymerizable surfactant as a polymerizable surfactant 0.8 parts by mass of Neogen SC-F and 169.7 parts by mass of ion-exchanged water were charged, and the temperature inside the container was raised to 130 ° C. while stirring.

  Into the polymerization vessel, 10.2 parts by mass of aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass) was charged and held for 15 minutes, and then the emulsion and aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass). 30.5 parts by mass were dropped into the polymerization vessel over 3 hours.

  After completion of the dropwise addition, the polymerization vessel is maintained at an internal temperature of 130 ° C. for 1 hour, and then the polymerization vessel is cooled to about 25 ° C., and then the content is filtered through a 200 mesh filter cloth (polyester) to obtain a non-volatile content of 30. A tackifier (2) containing a vinyl polymer (2) having a content of 2% by mass, a particle diameter of 134 nm, and a weight average molecular weight of 5100 was obtained.

<< Example 3 >> Tackifier (3)
Lateoxyl PD-104 (manufactured by Kao Corporation, the addition mole number of oxyethylene is 15 moles, and the addition mole number of oxybutylene is 6 moles in a container equipped with a stirrer. -Polyoxyalkylene alkenyl ether sulfate ammonium salt having a polyoxybutylene structure and a sulfate ester structure, a polymerizable surfactant (non-volatile content 20% by mass) 2.5 parts by weight as a non-polymerizable surfactant 1.1 parts by mass of Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd., sodium dodecylbenzenesulfonate, nonvolatile content 63% by mass), 98 parts by mass of cyclohexyl methacrylate, 2 parts by mass of dimethylacrylamide, The transfer agent was charged with 2.2 parts by mass of lauryl mercaptan and 25 parts by mass of ion-exchanged water. , By stirring, to prepare an emulsion.

  The inside of the polymerization vessel equipped with a thermometer, a dripping device, a reflux condenser and a stirring device is replaced with nitrogen gas, and 12.5 parts by mass of the Latem PD-104 as a non-polymerizable surfactant as a polymerizable surfactant 0.8 parts by mass of Neogen SC-F and 167.5 parts by mass of ion-exchanged water were charged, and the temperature inside the container was raised to 130 ° C. while stirring.

  Into the polymerization vessel, 10.2 parts by mass of aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass) was charged and held for 15 minutes, and then the emulsion and aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass). 30.5 parts by mass were dropped into the polymerization vessel over 3 hours.

  After completion of the dropwise addition, the polymerization vessel is maintained at an internal temperature of 130 ° C. for 1 hour, and then the polymerization vessel is cooled to about 25 ° C., and then the content is filtered through a 200 mesh filter cloth (polyester) to obtain a non-volatile content of 30. A tackifier (3) containing 4% by mass, a particle diameter of 98 nm, and a vinyl polymer (3) having a weight average molecular weight of 4500 was obtained.

<< Comparative Example 1 >> Comparative tackifier (1 ')
A container equipped with a stirrer is charged with 1.8 parts by mass of neogen SC-F as a non-polymerizable surfactant, 100 parts by mass of cyclohexyl methacrylate, and 22 parts by mass of ion-exchanged water, and stirred. To prepare an emulsion.

  The inside of a pressurized closed polymerization vessel equipped with a thermometer, a dropping device, a reflux condenser and a stirring device was replaced with nitrogen gas, and 3.5 parts by mass of neogen SC-F and ion-exchanged water 182 as a non-polymerizable surfactant. 2 parts by mass were charged, and the temperature inside the container was raised to 130 ° C. while stirring.

  In the polymerization vessel, 10.2 parts by mass of aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass) was charged and held for 15 minutes, and then the emulsion and aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass). 30.5 parts by mass was dropped into the polymerization vessel over 3 hours.

  After completion of the dropping, the polymerization vessel is kept at an internal temperature of 130 ° C. for 1 hour, and then the polymerization vessel is cooled to about 25 ° C., and then the content is filtered through a 200 mesh filter cloth (polyester) to obtain a solid content of 29 A tackifier (1 ′) containing a vinyl polymer (1 ′) having 4 mass%, a particle diameter of 114 nm, and a weight average molecular weight of 5,500 was obtained.

<< Comparative Example 2 >> Comparative tackifier (2 ')
In a container equipped with a stirrer, 2.5 parts by mass of latem PD-104 as a polymerizable surfactant, 1.1 parts by mass of neogen SC-F as a non-polymerizable surfactant, and 100 parts by mass of cyclohexyl methacrylate Part and 25 parts by mass of ion-exchanged water were prepared and stirred to prepare an emulsion.

  The inside of a pressurized closed polymerization vessel equipped with a thermometer, a dropping device, a reflux condenser, and a stirring device was replaced with nitrogen gas, and 12.5 parts by weight of Latem PD-104 as a polymerizable surfactant, non-polymerizable surfactant As an agent, 0.8 parts by mass of Neogen SC-F and 169.7 parts by mass of ion-exchanged water were charged, and the temperature inside the container was raised to 130 ° C. while stirring.

  In the polymerization vessel, 10.2 parts by mass of aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass) was charged and held for 15 minutes, and then the emulsion and aqueous hydrogen peroxide solution (nonvolatile content 12.4% by mass). 30.5 parts by mass was dropped into the polymerization vessel over 3 hours.

  After completion of the dropping, the polymerization vessel is kept at an internal temperature of 130 ° C. for 1 hour, and then the polymerization vessel is cooled to about 25 ° C., and then the content is filtered through a 200 mesh filter cloth (polyester) to obtain a solid content of 29 A tackifier (2 ') containing a vinyl polymer (2') having a mass ratio of 6 mass%, a particle diameter of 78 nm and a weight average molecular weight of 5300 was obtained.

Example 4
After mixing 194.2 parts by mass of the aqueous dispersion of the acrylic resin (C-1) and 83.3 parts by mass of the tackifier (1), 12.5% by mass of ammonia water and Boncoat 3750-E. A mixture adjusted to pH 8 and BM viscosity of 10000 mPa · s was obtained by mixing (thickener manufactured by DIC Corporation, non-volatile content: 23% by mass).
Next, 0.29 parts by mass of an ethanol solution (non-volatile content 10% by mass) of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd., oil-soluble epoxy compound) as a crosslinking agent is mixed and filtered through a 200 mesh filter cloth (polyester). As a result, an aqueous pressure-sensitive adhesive (1) was obtained.

Example 5
After mixing 194.2 parts by mass of the aqueous dispersion of the acrylic resin (C-1) and 82.8 parts by mass of the tackifier (2), 12.5% by mass of ammonia water and Boncoat 3750-E. A mixture adjusted to pH 8 and BM viscosity of 10000 mPa · s was obtained by mixing (thickener manufactured by DIC Corporation, non-volatile content: 23% by mass).
Next, 0.29 parts by mass of an ethanol solution (non-volatile content 10% by mass) of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd., oil-soluble epoxy compound) as a crosslinking agent is mixed and filtered through a 200 mesh filter cloth (polyester). As a result, an aqueous pressure-sensitive adhesive (2) was obtained.

Example 6
After mixing 194.2 parts by mass of the aqueous dispersion of the acrylic resin (C-1) and 82.2 parts by mass of the tackifier (3), 12.5% by mass of ammonia water and Boncoat 3750-E. A mixture adjusted to pH 8 and BM viscosity of 10000 mPa · s was obtained by mixing (thickener manufactured by DIC Corporation, non-volatile content: 23% by mass).
Next, 0.28 parts by mass of ethanol solution (non-volatile content 10% by mass) of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd., oil-soluble epoxy compound) as a crosslinking agent is mixed and filtered through a 200 mesh filter cloth (polyester). As a result, an aqueous pressure-sensitive adhesive (3) was obtained.

<< Comparative Example 3 >>
194.2 parts by mass of an aqueous dispersion of the acrylic resin (C-1) and 50 parts by mass of Superester E-865NT (manufactured by Arakawa Chemical Co., Ltd., tackifier containing a polymerized rosin emulsion, nonvolatile content 50%) After mixing, 12.5 mass% ammonia water and Boncoat 3750-E (a thickener manufactured by DIC Corporation, non-volatile content 23 mass%) are mixed to adjust the pH to 8 and the BM viscosity to 10,000 mPa · s. The resulting mixture was obtained.
Next, 0.27 parts by mass of an ethanol solution (non-volatile content 10% by mass) of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd., oil-soluble epoxy compound) as a crosslinking agent is mixed and filtered through a 200 mesh filter cloth (polyester). As a result, an aqueous pressure-sensitive adhesive (3 ′) was obtained.

<< Comparative Example 4 >>
After mixing 194.2 parts by mass of the aqueous dispersion of the acrylic resin (C-1) and 50 parts by mass of the tackifier (1 ′), 12.5% by mass of ammonia water and Boncoat A mixture adjusted to pH 8 and BM viscosity of 10,000 mPa · s was obtained by mixing 3750-E (a thickener manufactured by DIC Corporation, nonvolatile content 23 mass%).
Next, 0.27 parts by mass of an ethanol solution (non-volatile content 10% by mass) of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd., oil-soluble epoxy compound) as a crosslinking agent is mixed and filtered through a 200 mesh filter cloth (polyester). As a result, an aqueous pressure-sensitive adhesive (3 ′) was obtained.

<< Comparative Example 5 >>
After mixing 194.2 parts by mass of the aqueous dispersion of acrylic resin (C-1) and 84.5 parts by mass of the tackifier (2 ′), 12.5% by mass of ammonia water and Boncoat 3750- A mixture adjusted to pH 8 and BM viscosity of 10000 mPa · s was obtained by mixing E (a thickener manufactured by DIC Corporation, nonvolatile content: 23 mass%).
Next, 0.23 parts by mass of an ethanol solution (non-volatile content 10% by mass) of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd., oil-soluble epoxy compound) as a crosslinking agent is mixed and filtered through a 200 mesh filter cloth (polyester). As a result, an aqueous pressure-sensitive adhesive (4 ′) was obtained.

[Preparation of adhesive sheet]
The aqueous pressure-sensitive adhesive was applied to the surface of a film made of polyethylene terephthalate having a thickness of 25 μm using an applicator so that the thickness of the pressure-sensitive adhesive layer formed by drying was 60 μm.

  Next, the coating film is dried in a drying oven at 100 ° C. for 3 minutes, and a release film made of polyethylene terephthalate having a thickness of 25 μm and placed on the surface of the coating film is placed on the surface of the coating film. By carrying out 1 reciprocating load using a roller, they were crimped | bonded and the laminated body was obtained.

  The obtained laminate was allowed to stand in an atmosphere of 40 ° C. for 48 hours and aged to obtain an adhesive sheet.

[Evaluation method of gel fraction]
A test piece was prepared by cutting the pressure-sensitive adhesive sheet produced by the above method into a size of 20 mm in length and 100 mm in width. The total mass of the pressure-sensitive adhesive layer from which the 25 μm release film was removed from the test piece and the support was measured using a precision balance (W1).

  Next, the pressure-sensitive adhesive layer was immersed in 50 cc of toluene for 24 hours and then dried in a drying oven at 100 ° C. for 2 hours. The mass (W2) of the pressure-sensitive adhesive layer after drying was measured using a precision balance.

  The gel fraction was calculated based on (mass (W2) −mass of support) / (mass (W1) −support) × 100.

[Adhesion evaluation method]
Adhesiveness was evaluated by the following adhesive force (immediately after production of the pressure-sensitive adhesive sheet) and constant load holding force.
[Evaluation method of adhesive strength (immediately after production of adhesive sheet)]
A test piece obtained by cutting the pressure-sensitive adhesive sheet obtained by the above method into a size of width 20 mm × length 100 mm was used. In an atmosphere of 23 ° C. and 50% humidity, the release film is removed from the test piece, and a SUS (BA) substrate (manufactured by Engineering Test Service Co., Ltd.) is placed on the surface of the pressure-sensitive adhesive layer. They were bonded by applying a reciprocating load of 5 kg rolls and allowed to stand for 1 hour.

  Next, the adhesive strength between the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive sheet and the SUS base material in an atmosphere of 23 ° C. and a humidity of 50% is compliant with JIS Z 0237 at a speed of 180 mm direction and 300 mm / min. The peel strength when peeled was measured.

[Method for evaluating adhesive strength after wet heat test]
A test piece obtained by cutting the pressure-sensitive adhesive sheet obtained by the above method into a size of width 20 mm × length 100 mm was used. By removing the release film from the test piece in an atmosphere of 23 ° C. and 50% humidity, placing a SUS substrate on the surface of the pressure-sensitive adhesive layer, and applying a load of one reciprocating 5 kg roll from the upper part, They were pasted together.

  Next, the laminate composed of the pressure-sensitive adhesive sheet and the polypropylene base material was allowed to stand for 500 hours in an atmosphere of 70 ° C. and 95% humidity, and then taken out in an atmosphere of 23 ° C. and 50% humidity for 1 hour. After that, the adhesive strength between the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive sheet and the SUS base material is set at a speed of 300 mm / min in the 180 degree direction in accordance with JIS Z 0237 in an atmosphere of 23 ° C. and 50% humidity. The peel strength when peeled was measured.

[Method of evaluating wet heat resistance]
The wet heat resistance was evaluated based on the ratio (retention rate) of the adhesive force after the wet heat test to the adhesive force immediately after production of the pressure-sensitive adhesive sheet. Specifically, the evaluation was made based on the retention calculated based on the formula of [(adhesive strength after wet heat test) / (adhesive strength immediately after production)] × 100 (%).

  When the retention rate is 80% or more, it is evaluated as “◎”, when it is 60% or more and less than 80%, it is evaluated as “◯”, and when it is 40% or more and less than 60%, “△”. When it was 0% or more and less than 40%, it was evaluated as “x”.

[Method for evaluating constant load holding force]
A test piece obtained by cutting the pressure-sensitive adhesive sheet obtained by the above method into a size of 20 mm in length and 80 mm in width was used. By removing the release film from the test piece in an atmosphere of 23 ° C. and 50% humidity, placing a polypropylene base material on the surface of the pressure-sensitive adhesive layer, Were pasted together. After leaving still for 24 hours in an atmosphere of 23 ° C. and 50% humidity, a load of 100 g was applied so that the angle would be 90 °, and the measurement was started in an atmosphere of 40 ° C. Evaluation was made based on the distance shifted after 30 minutes, and those that dropped in less than 30 minutes were recorded for that time.
In addition, when the shifted distance was less than 5 mm, it was evaluated as “◯”, when it was 5 mm or more and less than 10 mm, it was evaluated as “Δ”, and when it was 10 mm or more, it was evaluated as “x”.

  It turned out that Examples 4-6 which are the water-based adhesives using the tackifier of this invention are excellent in adhesiveness (especially the constant load holding power to a difficult-to-adhere base material) and wet heat resistance.

  On the other hand, Comparative Example 3 is an embodiment in which a polymerized rosin tackifier was used, but the heat and moisture resistance was poor, and the constant load holding force to polypropylene, which is a difficult-to-adhere substrate, was insufficient.

  Comparative Example 4 is an embodiment in which a tackifier that is not polymerized with a polymerizable emulsifier is used, but both the heat-and-moisture resistance and the constant load holding force to polypropylene are poor.

  Although the comparative example 5 is an aspect using the tackifier which has not superposed | polymerized the vinyl monomer which has a nitrogen atom, the constant load holding power to a polypropylene was inadequate.

Claims (11)

A vinyl weight having a weight average molecular weight of 500 to 30,000 obtained by polymerizing the monomer (a) having the polymerizable surfactant (a1) and the vinyl monomer (a2) having a nitrogen atom as essential components. A tackifier containing the coalescence (A). The vinyl polymer (A) polymerizes a monomer (a) containing a polymerizable surfactant (a1), a vinyl monomer (a2) having a nitrogen atom, and another vinyl monomer (a3). The tackifier according to claim 1, wherein the tackifier is obtained. The tackifier according to claim 1, wherein the polymerizable surfactant (a1) has a polyoxyethylene structure or a sulfate ester structure. The tackifier according to claim 1, wherein the polymerizable surfactant (a1) is contained in a range of 0.1% by mass to 5% by mass with respect to the total amount of the monomer (a). The tackifier according to claim 2, wherein the other vinyl monomer (a3) contains a (meth) acrylic acid alkyl ester having an alicyclic structure. The tackifier according to claim 5, wherein the (meth) acrylic acid alkyl ester having an alicyclic structure is contained in a range of 50% by mass to 99% by mass with respect to the total amount of the monomer (a). The tackifier according to claim 1, wherein the vinyl monomer (a2) having a nitrogen atom has an amide group and / or a lactam ring. The tackifier according to claim 1, further comprising an aqueous medium (B). The tackifier according to any one of claims 1 to 8, an aqueous medium, and an acrylic resin (C) having a glass transition temperature of -10 ° C or lower and a weight average molecular weight of 100,000 or higher. A composition for aqueous pressure-sensitive adhesives. The aqueous adhesive obtained using the composition for aqueous adhesives of Claim 9. A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed using the aqueous pressure-sensitive adhesive according to claim 10 on the surface of a base material.