JP5478849B2 - Aqueous pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet using the same - Google Patents

Description

  The present invention relates to an aqueous pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet such as a pressure-sensitive adhesive tape or a pressure-sensitive adhesive label using the same. In particular, the present invention is excellent in adhesion, adhesiveness, initial tackiness and holding power to a substrate (foam) having an uneven surface such as urethane foam, excellent in water resistance and generation of VOC. The present invention relates to an aqueous pressure-sensitive adhesive composition that can significantly reduce the amount of water and a pressure-sensitive adhesive sheet using the same.

  Conventionally, organic solvent-based pressure-sensitive adhesives have been used in a variety of fields because of their excellent physical properties such as adhesion to substrates, but in recent years, environmental problems and when applying pressure-sensitive adhesives have been used. From the viewpoint of safety and hygiene, etc., development of an aqueous pressure-sensitive adhesive that generates relatively little VOC is underway. However, compared with organic solvent-based pressure-sensitive adhesives, water-based pressure-sensitive adhesives are peeled off between the base material and the pressure-sensitive adhesive layer when the base material is a foam having an uneven surface such as urethane foam. There is a problem that it is likely to occur. For this reason, various devices have been devised in order to develop an aqueous pressure-sensitive adhesive that generates less VOC and is excellent in adhesion, adhesion, and holding power to the substrate.

  For example, a polymer emulsion obtained by polymerizing a radically polymerizable unsaturated monomer in the presence of a surfactant, an adhesive comprising inorganic particles and crosslinked organic particles (see Patent Document 1), (meth) acrylic acid A pressure-sensitive adhesive composition containing an acrylic polymer having an ester as a main component and a stabilized rosin ester resin as a tackifier (see Patent Document 2), alkyl (meth) acrylate, polymerizable unsaturated carboxylic acid, alcohol An aqueous pressure-sensitive adhesive composition obtained by emulsion polymerization of a mixture of a copolymerizable vinyl monomer having an ionic hydroxyl group, acetoacetoxyethyl methacrylate, and a terpene-based tackifier resin (see Patent Document 3), (meth) acrylic Acid alkyl ester, hydroxyalkyl (meth) acrylate, and a mixture containing a solid resin having a softening point exceeding 85 ° C The aqueous dispersion obtained by emulsion polymerization (see Patent Document 4) are disclosed. However, none of these uses rosin-based or terpene-based tackifiers, and does not sufficiently suppress the occurrence of VOC. Also, the substrate adhesion to the foam, adhesiveness, initial tack The properties, holding power, and water resistance were not sufficient.

  Further, in order to improve the adhesion to the polyolefin adherend and adhesion retention, for example, an emulsion of a carbonyl group-containing polymer, a compound containing two or more hydrazino groups in the molecule, and a ketone having a boiling point of 100 ° C. or less An aqueous pressure-sensitive adhesive composition containing a system solvent (see Patent Document 5) is disclosed. Furthermore, an emulsion-type pressure-sensitive adhesive obtained by polymerizing a monomer-containing emulsion composed of a polymerizable unsaturated monomer mainly composed of (meth) acrylic acid ester, a tackifier resin containing a rosin-based tackifier resin, etc. (Patent Document) 6) is also disclosed. These use a crosslinking agent having a hydrazino group to improve adhesion to a substrate, but use a rosin-based or terpene-based tackifier and can sufficiently solve the problem of VOC generation. It was not a thing.

  Furthermore, an acrylic polymer obtained by emulsion polymerization of a polymerizable monomer component containing a carboxyl group-containing ethylenically unsaturated monomer and an alkyl (meth) acrylate was further crosslinked with an oil-soluble epoxy compound. Acrylic aqueous pressure-sensitive adhesive (see Patent Document 7), acrylic water-dispersed copolymer having a weight average molecular weight of 400,000 to 900,000, and acrylic water-dispersed low molecular weight having a weight average molecular weight of 5,000 to 250,000 An acrylic water-dispersed pressure-sensitive adhesive composition containing components (see Patent Document 8), a (meth) acrylic acid ester monomer and a vinyl monomer having an acidic group are emulsion-polymerized using a water-soluble azo initiator. It is disclosed that a terpene resin is used as a tackifier in the acrylic adhesive resin obtained by the above (see Patent Document 9). These improve the adhesion to the substrate using a crosslinking agent having an epoxy group, but use a rosin-based or terpene-based tackifier and do not sufficiently suppress the occurrence of VOCs. It was.

On the other hand, not only various physical properties such as adhesion to the substrate but also proposals for suppressing the occurrence of VOC have been made. For example, it contains (meth) acrylic acid alkyl ester copolymer emulsion and tackifying resin,
An aqueous pressure-sensitive adhesive (see Patent Document 10) having a total volatile organic compound measured by A1901 method (small chamber method) of 3,000 μg / m ³ or less, a formaldehyde emission amount of less than 3 μg / m ³ , and toluene A pressure-sensitive adhesive sheet (refer to Patent Document 11) having a diffusion amount of 10 μg / g or less is disclosed. However, in any case, it cannot be said that the substrate adhesion to the foam, the adhesiveness, the initial tackiness, the holding power, and the water resistance are sufficient.

JP 2007-169569 A JP 2006-96895 A JP 2008-81564 A JP 2008-81691 A JP 2008-7724 A JP 2007-224185 A JP 2007-217594 A JP 2007-262380 A JP 2006-348143 A JP-A-2005-307114 JP 2006-111818 A

  The present invention is excellent in adhesion, adhesion, initial tackiness, holding power to a substrate (foam) having an uneven surface such as urethane foam, excellent in water resistance, and extremely low occurrence of VOC. An object of the present invention is to provide an aqueous pressure-sensitive adhesive composition that can be used, and a pressure-sensitive adhesive sheet using the same.

The present invention relates to a polymer emulsion (A) obtained by emulsion polymerization of an ethylenically unsaturated monomer component containing a carbonyl group-containing ethylenically unsaturated monomer, a tackifier comprising a petroleum resin (B) , a molecule The present invention relates to an aqueous pressure-sensitive adhesive composition comprising a compound (C) having at least two hydrazino groups therein and a crosslinking agent (D) having at least two epoxy groups in the molecule .

（式中、ｎは１〜２２の整数である）で表される化合物であることが好ましい。 The crosslinking agent (D) having at least two epoxy groups in the molecule is represented by the formula (1):

It is preferable that it is a compound represented by (In formula, n is an integer of 1-22.).

  It is preferable to contain 0.1-10 mass parts of crosslinking agents (D) which have at least 2 epoxy group in a molecule | numerator with respect to 100 mass parts of solid content of a polymer emulsion (A).

  It is preferable that a carbonyl group containing ethylenically unsaturated monomer is 0.1-5 mass% with respect to an ethylenically unsaturated monomer component.

  It is preferable to contain 1-15 mass parts of tackifier (B) which consists of petroleum-type resin with respect to 100 mass parts of solid content of a polymer emulsion (A).

  It is preferable to contain 0.1 to 5 parts by mass of the compound (C) having at least two hydrazino groups in the molecule with respect to 100 parts by mass of the solid content of the polymer emulsion (A).

  The present invention relates to an aqueous pressure-sensitive adhesive composition for foams comprising the aqueous pressure-sensitive adhesive composition.

  Moreover, this invention relates to the adhesive sheet by which the adhesive layer formed from the said aqueous adhesive composition was laminated | stacked on the at least one surface of the sheet | seat. In particular, the sheet (base material) is preferably a foam.

  According to the present invention, the adhesiveness to a base material (foam) having an uneven surface such as urethane foam (foam), excellent adhesion (peeling force), initial tackiness, holding power, excellent water resistance, and It is possible to provide an aqueous pressure-sensitive adhesive composition capable of extremely reducing the occurrence of VOC, and a pressure-sensitive adhesive sheet using the same.

  The aqueous pressure-sensitive adhesive composition of the present invention comprises a polymer emulsion (A) obtained by emulsion polymerization of an ethylenically unsaturated monomer component containing a carbonyl group-containing ethylenically unsaturated monomer, and a tackifier comprising a petroleum resin. It consists of an agent (B) and a compound (C) having at least two hydrazino groups in the molecule.

  Examples of the ethylenically unsaturated monomer used in the production of the polymer emulsion (A) include acrylic acid esters (methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl ( (Meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, etc.), aromatic vinyl compound (Styrene, α-methylstyrene, p-methylstyrene, ethyl vinylbenzene, etc.), heterocyclic vinyl compounds (vinyl pyrrolidone, etc.), hydroxyalkyl (meth) acrylate (2-hydroxyethyl (meth) acrylate, 2- Droxypropyl (meth) acrylate, etc.), polyalkylene glycol (meth) acrylate (ethylene glycol (meth) acrylate, butylene glycol (meth) acrylate etc.), alkylamino (meth) acrylate (N, N-dimethylaminoethyl ( (Meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, etc.), vinyl ester compounds (vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate), monoolefin compounds (ethylene, propylene, butylene, isobutylene, etc.) , Conjugated diolefin compounds (butadiene, isoprene, chloroprene, etc.), α, β-unsaturated mono- or dicarboxylic acids (acrylic acid, methacrylic acid, crotonic acid, citraconic acid, itaconic acid, maleic anhydride, maleic anhydride Inic acid, fumaric acid, etc.), carboxyl group-containing vinyl compounds (monohydroxyethyl (meth) acrylate phthalate, monohydroxypropyl (meth) acrylate) oxalate, etc., vinyl compounds containing amine imide groups (1,1,1-trimethylamine methacrylic) Imide), vinyl cyanide compounds (acrylonitrile, methacrylonitrile, etc.), amide group or substituted amide group-containing α, β-ethylenically unsaturated compounds ((meth) acrylamide, N-methylacrylamide, N, N-dimethyl ( (Meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, etc.), sulphonic acid group-containing α, β-ethylenically unsaturated compounds (allyl sulphonate, sodium p-styrene sulphonate, etc.), ethylenically unsaturated groups Containing UV absorber (2- (2 -Hydroxy-5'-methacryloyloxyethylphenyl) -2H-benzotriazole, etc.), ethylenically unsaturated group-containing light stabilizers (1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, etc.), etc. And known polymerizable vinyl compounds. Of these, n-butyl acrylate, 2-ethylhexyl acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyalkyl (meth) acrylate (2) are excellent in stability during polymerization of the polymerizable monomer component. -Hydroxyethyl (meth) acrylate), acrylic acid and methacrylic acid are preferred.

  The carbonyl group-containing ethylenically unsaturated monomer has a keto group or an aldehyde group in the molecule, and is a component that undergoes a crosslinking reaction with the compound (C) having at least two hydrazino groups in the molecule described later. The carbonyl group-containing ethylenically unsaturated monomer contained in the ethylenically unsaturated monomer component includes (meth) acrolein, diacetone acrylate, alkyl vinyl ketone (vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, etc. ), Diacetone (meth) acrylate, acetoacetoxyethyl (meth) acrylate, acetonitrile (meth) acrylate, and formylstyrene. Of these, diacetone acrylic amide, (meth) acrolein and the like are preferable because of excellent stability during polymerization. The carbonyl group-containing ethylenically unsaturated monomer is 0% relative to all components (including the carbonyl group-containing ethylenically unsaturated monomer) of the ethylenically unsaturated monomer used in the production of the polymer emulsion (A). It is preferable that it is 1-5 mass%, and it is more preferable that it is 0.1-1 mass%. When the carbonyl group-containing ethylenically unsaturated monomer is less than 0.1% by mass with respect to the total components of the ethylenically unsaturated monomer, the crosslinking rate decreases, and it becomes difficult to ensure a sufficient crosslinking density. Heat resistance, holding power, etc. are insufficient, and if it exceeds 5% by mass, the physical properties of the adhesive tend to be lowered and the cost is increased.

  Moreover, you may use a crosslinkable monomer for an ethylenically unsaturated monomer as needed. Examples of crosslinkable monomers include epoxy group-containing α, β-ethylenically unsaturated compounds (glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl vinyl ether, glycidyl (meth) allyl ether, 3,4). -Epoxycyclohexyl (meth) acrylate, etc.), hydrolyzable alkoxysilyl group-containing α, β-ethylenically unsaturated compounds (vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, etc. ), Polyfunctional vinyl compounds (ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, divinylbenzene, diallyl phthalate, etc.) and the like.

  The glass transition temperature of the polymer emulsion (A) is preferably −10 to −60 ° C., and more preferably −30 to −60 ° C. When the glass transition temperature is lower than −60 ° C., the cohesive strength of the polymer is low, and the heat resistance, holding power, die-cutting property, etc. are insufficient, and when it is higher than −10 ° C., the adhesiveness is low and the initial adhesive strength is particularly poor. It tends to be sufficient.

  The surfactant that can be used for the production of the polymer emulsion (A) is not particularly limited. Specifically, anionic surfactants such as sodium dodecylbenzenesulfonate and sodium dodecylsulfate, nonionic surfactants such as polyoxyethylene lauryl ether and polyoxyethylene nonylphenyl ether, cesyltrimethylammonium bromide, laurylpyridinium chloride, etc. Cationic surfactants, amphoteric surfactants such as laurylbedine, other reactive surfactants, and the like. These may be used alone or in combination.

  Polymerization initiators used in emulsion polymerization include persulfate initiators such as potassium persulfate and ammonium persulfate, and water-soluble azo initiators such as 2,2′-azobis (2-methylpropionamidine) dihydrochloride. Agents, organic peroxides such as t-butyl hydroperoxide and cumene hydroperoxide, hydrogen peroxide and the like. These polymerization initiators may be used alone or in combination.

  Moreover, a reducing agent can be used with these polymerization initiators as needed. Such reducing agents include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, glucose, formaldehyde sulfoxylate metal salts, reducing properties such as sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium metabisulfite And inorganic compounds.

  Furthermore, in emulsion polymerization, a chain transfer agent can be used as necessary, but the amount used should be examined so that physical properties such as substrate adhesion, adhesiveness, initial tackiness, and holding power do not become a problem. The amount of use is adjusted according to its use and specifications. Examples of such chain transfer agents include n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, 2-ethylhexyl thioglycolate, 2-mercaptoethanol, β-mercaptopropionic acid, methyl alcohol, n-propyl alcohol, Examples include isopropyl alcohol, t-butyl alcohol, benzyl alcohol and the like.

の構造式で表される骨格を有する石油系樹脂、又はこの石油系樹脂を水素化した式（３）：

の構造式で表される骨格を有する石油系樹脂が好ましい。これらの石油系樹脂は単独または混合物であっても良い。また、式（２）の構造式で表される骨格を有する石油系樹脂を、部分的に水素化したものであっても良い。石油系樹脂中の芳香環に対する水素化率は５０〜１００％が好ましく、５０％より少なくなると、臭気、色調、加熱安定性、耐候性が悪化する。石油系樹脂からなる粘着付与剤（Ｂ）は、粘着性を付与する効果に優れているという点から、数平均分子量が６００〜１０００であることが好ましい。石油系樹脂からなる粘着付与剤（Ｂ）は、ポリマーエマルジョン（Ａ）の固形分１００質量部に対し、１〜１５質量部であることが好ましく、３〜１０質量部であることがより好ましい。１質量部より少なくなると、ポリオレフィンに対する密着性が低下しとなり、１５質量部より多くなると、ポリマーとの相溶性が悪くなり、ポリマー皮膜が白化する傾向にある。 The tackifier (B) used in the present invention comprises a petroleum resin. From the viewpoint of workability when added to the polymer emulsion (A) and the storage stability of the aqueous pressure-sensitive adhesive composition, it is preferable to use an emulsion type. By using a petroleum-based resin, unlike the case of using a rosin-based or terpene-based tackifier, generation of VOCs such as toluene and acetaldehyde can be suppressed. Examples of the petroleum resin include aromatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aliphatic / aromatic petroleum resins, and hydrogenated products thereof. Examples of the aromatic hydrocarbon resin include polymers of vinyl group-containing aromatic hydrocarbons having 8 to 10 carbon atoms (styrene, vinyl toluene, α-methyl styrene, indene, methyl indene). Aliphatic cyclic hydrocarbon resins include polymers obtained by cyclization and dimerization of “C4 petroleum fraction” and “C5 petroleum fraction”, cyclic diene compounds (cyclopentadiene, dicyclopentadiene, ethylidene norbornene). , Dipentene, etc.). Examples of the aliphatic / aromatic petroleum resins include styrene-olefin copolymers. Among these, in terms of adhesion to a polyolefin substrate and compatibility with a polymer, the formula (2):

A petroleum-based resin having a skeleton represented by the structural formula: or a formula (3) obtained by hydrogenating this petroleum-based resin:

A petroleum resin having a skeleton represented by the following structural formula is preferred. These petroleum resins may be used alone or as a mixture. Further, a petroleum resin having a skeleton represented by the structural formula of Formula (2) may be partially hydrogenated. 50-100% of the hydrogenation rate with respect to the aromatic ring in petroleum resin is preferable, and when it becomes less than 50%, odor, color tone, heat stability, and weather resistance will deteriorate. The tackifier (B) made of a petroleum resin preferably has a number average molecular weight of 600 to 1000 from the viewpoint that it has an excellent effect of imparting tackiness. The tackifier (B) made of petroleum resin is preferably 1 to 15 parts by mass and more preferably 3 to 10 parts by mass with respect to 100 parts by mass of the solid content of the polymer emulsion (A). When the amount is less than 1 part by mass, the adhesion to the polyolefin is lowered, and when the amount is more than 15 parts by mass, the compatibility with the polymer is deteriorated and the polymer film tends to be whitened.

  As described above, the compound (C) having at least two hydrazino groups in the molecule undergoes a crosslinking reaction with the keto group or aldehyde group derived from the carbonyl group-containing ethylenically unsaturated monomer in the polymer emulsion (A). Although it works, it works effectively as a catcher agent for low-molecular-weight organic compounds such as formaldehyde, so that the occurrence of VOC can be kept low. Examples of the compound (C) having at least two hydrazino groups in the molecule include dihydrazides of polyvalent carboxylic acids (succinic acid dihydrazide, adipic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, maleic acid dihydrazide, sebacic acid dihydrazide). , Itaconic acid dihydrazide, trimellitic acid dihydrazide, trimellitic acid trihydrazide), 1,3,5-tri (2-hydrazinocarbonylethyl) isocyanurate, 1,3-bis (hydrazinocarboethyl) -5-isopropyl Hydantoin etc. are mentioned. Of these, adipic acid dihydrazide and 1,3,5-tri (2-hydrazinocarbonylethyl) isocyanurate are preferable from the viewpoint of reactivity and solubility in water.

  The compound (C) having at least two hydrazino groups in the molecule is preferably 0.1 to 5 parts by mass, and 0.1 to 1 part by mass with respect to 100 parts by mass of the solid content of the polymer emulsion (A). It is more preferable that If the amount is less than 0.1 parts by mass, the crosslinking efficiency is low and the catcher effect of the low-molecular organic compound is also low, which is not effective. If the amount is more than 5 parts by mass, the compound may precipitate or the crosslinking may be too early, resulting in poor casting on the substrate. Moreover, it is preferable that molar ratio of the hydrazino group in a compound (C) and a carbonyl group containing ethylenically unsaturated monomer is 1: 10-10: 1. When the hydrazino group is more than 10: 1, the compound may be precipitated or the crosslinking may be too early, resulting in poor casting to the substrate. When the hydrazino group is less than 1:10, the crosslinking efficiency is low and the low molecular weight is low. It is not effective because the catcher effect of organic compounds is also reduced.

  Furthermore, the aqueous pressure-sensitive adhesive composition of the present invention contains a crosslinking agent (D) having at least two epoxy groups in the molecule from the viewpoints of substrate adhesion, adhesiveness, initial tackiness, holding power, and water resistance. It is preferable to do. The crosslinking agent (D) is preferably water-soluble from the viewpoints of crosslinking reactivity with the polymer emulsion (A) and dispersibility in the polymer emulsion. The epoxy group in the crosslinking agent (D) reacts with a carboxyl group, an amino group, a hydroxyl group or the like, and a carboxyl group derived from (meth) acrylic acid in the polymer emulsion (A) or a hydroxyalkyl (meth). A crosslinking reaction is suitably performed with hydroxyl groups derived from acrylate. When processing the pressure-sensitive adhesive sheet using the aqueous pressure-sensitive adhesive composition of the present invention, the crosslinking reaction by the crosslinking agent (D) proceeds gradually after processing, so by providing a curing period after processing the pressure-sensitive adhesive sheet, The substrate adhesion, adhesiveness, initial tackiness, holding power, and water resistance will be improved.

（式中、ｎは１〜２２の整数である）で表される化合物、式（４）：

（式中、ｍは１〜１１の整数である）で表される化合物、式（５）：

（式中、Ｒは水素又は

で表される基である）で表される化合物、式（６）：

（式中、ｐは２又は３である）で表される化合物、式（７）：

で表される化合物、式（８）：

で表される化合物、式（９）：

があげられる。なかでも、架橋反応性、ポリマーエマルジョン中への分散性の点で、式（１）で表される化合物が好ましい。式（１）で表される化合物において、ｎは１〜２２であることが好ましく、１〜１３であることがより好ましい。また、１〜９であることがさらに好ましい。ｎが２２より大きくなると、取り扱いにくくなる傾向にある。また、式（４）で表される化合物において、ｍは１〜１１であることが好ましく、２〜３であることがより好ましい。ｍが１１より大きくなると、水溶率が低下もしくは、水に不溶となりポリマーエマルジョン中への分散性が悪くなる傾向にある。 Although the molecular structure of the crosslinking agent (D) having at least two epoxy groups in the molecule is not particularly limited, for example, the formula (1):

(Wherein n is an integer of 1 to 22), a compound represented by formula (4):

A compound represented by the formula (wherein m is an integer of 1 to 11): Formula (5):

Where R is hydrogen or

A compound represented by formula (6):

(Wherein p is 2 or 3), a compound represented by formula (7):

A compound represented by formula (8):

A compound represented by formula (9):

Can be given. Especially, the compound represented by Formula (1) is preferable at the point of crosslinking reactivity and the dispersibility in a polymer emulsion. In the compound represented by the formula (1), n is preferably 1 to 22, and more preferably 1 to 13. Moreover, it is more preferable that it is 1-9. When n is larger than 22, the handling tends to be difficult. Moreover, in the compound represented by Formula (4), m is preferably from 1 to 11, and more preferably from 2 to 3. When m is greater than 11, the water content decreases or becomes insoluble in water and tends to deteriorate the dispersibility in the polymer emulsion.

  The crosslinking agent (D) is preferably 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the solid content of the polymer emulsion (A). More preferably, it is 1-1 mass part. When the amount is less than 0.1 parts by mass, the crosslinking rate is reduced, and it is difficult to secure a sufficient crosslinking density, and the heat resistance and holding power are insufficient. When the amount exceeds 10 parts by mass, the crosslinking is too early. Throwing failure occurs, the cohesive strength of the polymer increases, and the adhesive strength and initial adhesive strength tend to be insufficient.

  The adherend when using the aqueous pressure-sensitive adhesive composition of the present invention as the pressure-sensitive adhesive is not particularly limited, and examples thereof include paper, plastic film, metal, glass, woven fabric, nonwoven fabric, and foam having irregularities on the surface. In particular, it can be suitably used for foams. Examples of the foam include polyurethane, rubber, and EPDM. Moreover, this invention relates to the adhesive sheet by which the adhesive layer formed from the said aqueous adhesive composition was laminated | stacked on the at least one surface of the sheet | seat. The material of the sheet (base material) is not particularly limited, and examples include materials such as paper, plastic film, metal, glass, woven fabric, nonwoven fabric, and foam having irregularities on the surface, among which polyurethane. A foam made of rubber, rubber, EPDM or the like is suitably used as the material for the sheet.

  The use of the aqueous pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet of the present invention is not particularly limited. For example, it is used for the purpose of soundproofing, dustproofing, airtightness and moisture-proofing in automobiles, houses, home appliances, etc. Can do.

  Hereinafter, the present invention will be described in detail by way of examples. “Parts” in Examples and Comparative Examples indicates parts by mass.

(Production of polymer emulsion (i))
In a 2 L four-necked flask (hereinafter referred to as reaction vessel) equipped with a reflux condenser, stirrer, thermometer nitrogen inlet tube, and raw material inlet, 189 parts of ion-exchanged water, emulsifier Aqualon KH-10 (Daiichi Kogyo Seiyaku) 1 part) was added, and the internal temperature was heated to 78 ° C. On the other hand, as monomers, n-butyl acrylate 213.5 parts, 2-ethylhexyl acrylate 213.5 parts, methyl methacrylate 72 parts, 2-hydroxyethyl methacrylate 4.29 parts, acrylic acid 12.86 parts, diacetone acrylic Homogeneous mixture of 0.85 parts of amide, 0.86 parts of 2-ethylhexyl thioglycolate as a chain transfer agent, 4.3 parts of Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) as an emulsifier and 200 parts of ion-exchanged water. The mixture was emulsified with a mixer to prepare a monomer emulsion. In the above reaction vessel, 3% of the monomer emulsion was added, and at the same time, 0.31 part of potassium persulfate (hereinafter referred to as KPS) was added to initiate emulsion polymerization. Next, 20 minutes after adding KPS to the reaction vessel, a solution in which the remaining 97% of the monomer emulsion and 1.08 parts of KPS were dissolved in 16 parts of ion-exchanged water was added dropwise over 3.5 hours. . During this time, the inside of the reaction vessel was kept at 80 ° C. After completion of the dropwise addition, the mixture was kept at 80 ° C. for 1 hour and aged. Then, it cooled to 65 degreeC, 1 part of t-butyl hydroperoxide, 1 part of sodium bisulfite, and 10 parts of ion-exchange water were added, and the unreacted monomer was made to react. After maintaining at 65 ° C. for 3 hours, 6 parts of 35% aqueous ammonia was added and cooling was started. The obtained polymer emulsion (i) has a solid content of 53.1% (measurement method: measured at 105 ° C. for 1 hour), pH 8, viscosity of 3000 mPa · s (measurement method: 23 ° C. with BL type viscometer Measured at 10 rpm using a 4 rotor, measured in the same manner in the following examples and comparative examples), average particle diameter 150 nm (manufactured by Nikkiso Co., Ltd., average particle size using Microtrac UPA type particle size distribution measuring device The diameter (50% median diameter based on volume) was measured. In the following experimental examples, it was measured by the same method).

(Production of polymer emulsion (ii))
The polymer was used except that the acrylic acid in the monomer used for the polymerization was 6.43 parts, the chain transfer agent 2-ethylhexylthioglycolate was 0.43 parts, and the ammonia water added after the reaction was 4 parts. Operation similar to manufacture of emulsion (i) was performed, and polymer emulsion (B) was obtained. The polymer emulsion (ii) had a solid content of 53.1%, pH 8, a viscosity of 3000 mPa · s, and an average particle size of 150 nm.

Example 1
For 100 parts of the obtained polymer emulsion (i), an emulsion-type petroleum resin-based tackifier resin (Arakawa Chemical Industries, Ltd., Alcon M-100 (a petroleum resin having a skeleton having the structural formula of the above formula (2)) Hydride, aromatic ring hydrogenation rate 56%, number average molecular weight 800, solid content concentration 50%, softening point 100 ° C.) 66 parts, adipic acid dihydrazide 0.2 parts, water 3.8 parts, defoamer (product) Name: Adecanate B-940, manufactured by ADEKA Co., Ltd. 0.1 part, preservative (trade name: Neosynthol BC-60, manufactured by Sumika Enviro Science Co., Ltd.) 0.05 part, wetting agent (trade name: Surfynol) 0.1 parts of SE-F, manufactured by Air Products Japan Co., Ltd.) and a thickener (trade name: Primal ASE-60, manufactured by Rohm and Haas Japan Co., Ltd.) Parts, Denacol EX810 (manufactured by Nagase ChemteX Corporation, a compound having an epoxy group represented by the formula (1)) was added 0.1 part of a viscosity to obtain an aqueous pressure sensitive adhesive composition of 15000 mPa · s.

(Example 2)
An aqueous pressure-sensitive adhesive composition having a viscosity of 15000 mPa · s was obtained in the same manner as in Example 1 except that 100 parts of the polymer emulsion (ii) was used instead of 100 parts of the polymer emulsion (i).

(Comparative Example 1)
An aqueous pressure-sensitive adhesive having a viscosity of 15000 mPa · s, except that 100 parts of the polymer emulsion (ii) was used instead of 100 parts of the polymer emulsion (i) and that Denacol EX810 was not added. A composition was obtained.

(Comparative Example 2)
The same operation as in Example 1 except that 66 parts of super ester E-865NT (manufactured by Arakawa Chemical Industries, Ltd., rosin-based tackifying resin, solid content 50%) was used instead of the emulsion type petroleum resin-based tackifying resin. The aqueous pressure-sensitive adhesive composition having a viscosity of 15000 mPa · s was obtained.

(Comparative Example 3)
An aqueous pressure-sensitive adhesive composition having a viscosity of 15000 mPa · s was obtained in the same manner as in Example 1 except that Denacol EX810 was not added.

(Comparative Example 4)
The same operation as in Example 1 was performed except that 0.25 part of AQUANATE AQ-200 (manufactured by Nippon Polyurethane Industry Co., Ltd., isocyanate crosslinking agent) was used instead of Denacol EX810, and an aqueous solution having a viscosity of 15000 mPa · s. A pressure-sensitive adhesive composition was obtained.

Using the obtained water-based pressure-sensitive adhesive composition, the surface of the release paper was coated with the water-based pressure-sensitive adhesive composition so that the solid content after drying was 60 g / m ² and dried at 105 ° C. for 2 minutes. It was created. The pressure-sensitive adhesive sheet was passed through a roller having a clearance of 1 mm under an atmosphere of 23 ° C. × 50% RH, thereby being bonded to a polyether-type urethane foam to complete a test piece.

Various physical properties of the obtained test piece were evaluated by the following methods.
Substrate adhesion: A finger was pressed against the surface of the pressure-sensitive adhesive layer of the obtained test piece, and the pressure-sensitive adhesive layer and urethane foam were evaluated for visual destruction when slowly peeled off.
◯: There was no transfer of the pressure-sensitive adhesive layer to the finger, and the test piece retained the original shape. Alternatively, the urethane foam broke down, and the adhesive layer was transferred to the finger while being in close contact with the urethane foam.
X: The pressure-sensitive adhesive layer was separated from the urethane foam, transferred to the finger, and the pressure-sensitive adhesive layer was broken. Or although there was no transfer of the adhesive layer to the finger, the adhesive layer separated from the urethane foam.

  90 ° peeling force: In an atmosphere of 23 ° C. × 50% RH, the test piece was bonded to the adherend (SUS # 304 plate) by reciprocating the 2 kg roller once, and the 90 ° peeling force after being left for 20 minutes. It was measured. The peeling speed is 300 mm / min.

  Hot water resistance test: In an atmosphere of 23 ° C. × 50% RH, the test piece was bonded to the adherend (SUS # 304 plate) by reciprocating a 2 kg roller once and left for 24 hours. Immerse in warm water at 80 ° C for 72 hours. After leaving in water at 23 ° C. for 30 minutes, the 90 ° peeling force was measured in a state containing water.

  Initial adhesive strength: A 10 g weight (bottom area 1 cm) was bonded to a test piece of 25 mm × 120 mm by its own weight, and the initial adhesive strength after standing for 3 seconds was measured. The peeling speed was 200 mm / min.

  Holding power: The obtained test piece was left in an atmosphere of 23 ° C. × 50% RH for 20 minutes, and the holding power was measured. A load of 500 g was applied to the test piece, and the deviation between the adherend and the test piece after 1 hour was measured. The bonding area was 25 mm × 25 mm.

Measurement of VOC: Measurement was performed by a Tedlar back method using a test piece of 80 cm ² . The Tedlar back method is a method for collecting VOCs emitted from the target product set in the Tedlar back with a gas adsorption tube and analyzing and measuring the components by high performance liquid chromatography or gas chromatography mass spectrometry. .

  Table 1 shows the results of evaluating various physical properties of the aqueous pressure-sensitive adhesive compositions obtained in the steps of Examples 1 and 2 and Comparative Examples 1 to 4.

  From the comparison between Examples 1 and 2 and Comparative Examples 1 to 4, the water-based pressure-sensitive adhesive composition of the present invention has a small amount of VOC generation, and is a base material (foam) having irregularities on the surface like urethane foam. It can be seen that the adhesiveness, 90 ° peel strength (adhesiveness), warm water resistance, initial tackiness and holding power are also excellent.

Claims (9)

A polymer emulsion (A) obtained by emulsion polymerization of an ethylenically unsaturated monomer component containing a carbonyl group-containing ethylenically unsaturated monomer, a tackifier comprising a petroleum resin (B) , and at least 2 in the molecule An aqueous pressure-sensitive adhesive composition comprising a compound (C) having two hydrazino groups and a crosslinking agent (D) having at least two epoxy groups in the molecule . The crosslinking agent (D) having at least two epoxy groups in the molecule is represented by the formula (1):

(In the formula, n a is 1 to 22 integer) aqueous pressure-sensitive adhesive composition according to claim 1, wherein the compound represented by the. The aqueous pressure-sensitive adhesive composition according to claim 1 or 2, comprising 0.1 to 10 parts by mass of a crosslinking agent (D) having at least two epoxy groups in the molecule with respect to 100 parts by mass of the solid content of the polymer emulsion (A). object. The aqueous pressure-sensitive adhesive composition according to any one of claims 1, 2, and 3 , wherein the carbonyl group-containing ethylenically unsaturated monomer is 0.1 to 5% by mass relative to the ethylenically unsaturated monomer component. . The aqueous pressure-sensitive adhesive composition according to claim 1, 2, 3 or 4, comprising 1 to 15 parts by mass of a tackifier (B) made of a petroleum resin with respect to 100 parts by mass of the solid content of the polymer emulsion (A). To 100 parts by weight of the solid content of the polymer emulsion (A), a compound having at least two hydrazino groups in the molecule (C) according to claim 1, 2, 3, 4 or 5, wherein the containing 0.1-5 parts by weight An aqueous pressure-sensitive adhesive composition. An aqueous pressure-sensitive adhesive composition for foams comprising the aqueous pressure-sensitive adhesive composition according to any one of claims 1, 2, 3, 4, 5 and 6 . The adhesive sheet by which the adhesive layer formed from the aqueous adhesive composition in any one of Claim 1, 2, 3, 4, 5 or 6 was laminated | stacked on the at least one surface of the sheet | seat. The pressure-sensitive adhesive sheet according to claim 8 , wherein the sheet is a foam.