JP4645079B2 - Aqueous pressure-sensitive adhesive composition and method for producing the same - Google Patents

Description

The present invention relates to an aqueous pressure-sensitive adhesive composition. Specifically, the present invention relates to an aqueous pressure-sensitive adhesive composition having particularly good adhesion to a polyolefin adherend and excellent curved surface adhesion. More specifically, the present invention relates to an aqueous pressure-sensitive adhesive composition having the above characteristics, which is obtained by combining a plurality of aqueous resin composition dispersions having a specific composition.
Furthermore, this invention relates to the manufacturing method of the said aqueous adhesive composition.

  In recent years, solvent removal has progressed in consideration of health and safety and environmental problems, and it is desired to shift from a solvent type to a water-based type for adhesives. However, in water-based adhesives, emulsion particles are fused in the drying process after coating to form a dry film, so that the coating film is not as dense as solvent-based adhesives. In addition to the curved surface sticking property.

The curved surface sticking property is a term indicating aptitude in the case of sticking a pressure-sensitive adhesive coated product on a curved adherend. Unlike when pasted on a flat surface, when pasted on a curved surface, a stress is generated that causes the coated substrate to recover from a curved surface to a flat state. It works to peel off naturally. Therefore, if the adhesive force of the pressure-sensitive adhesive applied to the coated material is not sufficient, it will peel off naturally from the adherend after a certain period of time has elapsed after application. In addition, if the adhesive cohesive force is too low even though the adhesive adhesive strength is sufficiently high, a stress that causes the substrate to return to a flat state is usually caused by a phenomenon called “cohesive failure”. However, the adhesive itself is broken in the middle of the layer without winning, and the coated material is peeled off from the adherend. In this case, it will peel in the state in which an adhesive remains on both the adherend side and the substrate side.
Therefore, in order to improve the curved surface sticking property, the two physical property items of the adhesive force and the cohesive force of the pressure-sensitive adhesive must be satisfied without being significantly biased to either one.

  Conventionally, for example, increasing the content of long-chain alkyl (meth) acrylates by selecting the type of ethylenically unsaturated monomer that is the main raw material constituting the pressure-sensitive adhesive composition for the purpose of improving the adhesion to polyolefin adherends. For example, by reducing the glass transition temperature of the polymer to increase the adhesion of the pressure-sensitive adhesive, or by increasing the polymerization initiator to be used, the molecular weight of the polymer is decreased to increase the adhesiveness. However, these actions cause a decrease in the cohesive strength of the polymer, and for the reasons described above, no improvement can be seen with respect to curved surface sticking, and no solution has been reached.

  The subject of this invention is providing the aqueous adhesive composition which has the high adhesive force with respect to a polyolefin adherend, and the outstanding curved surface sticking property, and its manufacturing method.

1st invention is alkyl acrylate (a) 70-87.5 weight% whose carbon number of an alkyl group is 4-14, alkyl methacrylate (b) whose carbon number of an alkyl group is 1-2, 10-15 weight %, The alkyl part has 2 to 3 carbon atoms, a hydroxyalkyl (meth) acrylate (c) 2 to 6% by weight containing a hydroxyl group, and a monomer (d) 0.5 to 5 containing a carboxyl group A radically polymerizable ethylenically unsaturated monomer containing 5% by weight of an aqueous medium using 4 to 8 parts by weight of an emulsifier and a polymerization initiator based on 100 parts by weight of the total amount of the ethylenically unsaturated monomer A resin composition aqueous dispersion (A) obtained by polymerization in the polymer, an alkyl acrylate (a) having an alkyl group having 4 to 14 carbon atoms, 55 to 95% by weight, and a monomer containing a carboxyl group (D) 0. Radically polymerizable ethylenically unsaturated monomer containing ˜5% by weight of emulsifier and polymerization initiator in an amount of 1.5 to 3 parts by weight based on 100 parts by weight of the total amount of the ethylenically unsaturated monomer. And an aqueous resin dispersion for pressure-sensitive adhesives (B), which is polymerized in an aqueous medium, at a solid content weight ratio of (A) / (B) of 5/95 to 30/70 And a water-based pressure-sensitive adhesive composition characterized by further containing a crosslinking agent .

In the second invention, the alkyl acrylate (a) having an alkyl group having 4 to 14 carbon atoms is 70 to 87.5% by weight, and the alkyl methacrylate (b) having an alkyl group having 1 to 2 carbon atoms is 10 to 15% by weight. %, The alkyl part has 2 to 3 carbon atoms, a hydroxyl group-containing hydroxyalkyl (meth) acrylate (c) 2 to 6% by weight, and a carboxyl group-containing monomer (d) 0.5 to 5 An aqueous medium containing 4% by weight of an emulsifier and a polymerization initiator based on 100% by weight of the total amount of the ethylenically unsaturated monomer. A resin composition aqueous dispersion (A) obtained by polymerization in the polymer, an alkyl acrylate (a) having an alkyl group having 4 to 14 carbon atoms, 55 to 95% by weight, and a monomer containing a carboxyl group (D) 0.5 Using 1.5 to 3 parts by weight of an emulsifier and a polymerization initiator for radically polymerizable ethylenically unsaturated monomer containing 5% by weight with respect to 100 parts by weight of the total amount of the ethylenically unsaturated monomer And an aqueous dispersion (B) of the resin composition for pressure-sensitive adhesives polymerized in an aqueous medium at a solid content weight ratio of (A) / (B) of 5/95 to 30/70 , The present invention relates to a method for producing an aqueous pressure-sensitive adhesive composition characterized by blending and mixing a crosslinking agent .

  The water-based pressure-sensitive adhesive composition of the present invention exhibits excellent adhesion performance to polyolefin adherends that have conventionally been difficult to obtain good adhesion, and is particularly excellent in curved surface sticking properties. The coated product coated with the pressure-sensitive adhesive composition can be preferably used for an adherend having a curved shape.

<Adhesive resin composition aqueous dispersion (A)>
Among the radical polymerizable ethylenically unsaturated monomers used in the present invention, the alkyl acrylate (a) having an alkyl group having 4 to 14 carbon atoms includes butyl acrylate, hexyl acrylate, octyl acrylate, and 2-ethylhexyl acrylate. And acrylates of linear or branched aliphatic alcohols such as lauryl acrylate, and the like. Among them, alkyl acrylates having 4 to 12 carbon atoms in the alkyl group are preferably used, and these are ethylene constituting (A). 70 to 87.5% by weight of the total 100% by weight of the unsaturated unsaturated monomer, and can be used alone or in combination of two or more. When the amount used is less than 70% by weight, the adhesive strength is not sufficient, and when it exceeds 87.5% by weight, the effect of improving the curved surface sticking property cannot be sufficiently obtained.

  Among the radical polymerizable ethylenically unsaturated monomers used in the present invention, examples of the alkyl methacrylate (b) having 1 to 2 carbon atoms in the alkyl group include methyl methacrylate and ethyl methacrylate. These are contained in an amount of 10 to 15% by weight out of a total of 100% by weight of the ethylenically unsaturated monomers constituting (A), and can be used alone or in combination. When the amount used is less than 10% by weight, the effect of improving the curved surface sticking property cannot be obtained sufficiently, and when it exceeds 15% by weight, the adhesive force tends to decrease, such being undesirable.

  Of the radically polymerizable ethylenically unsaturated monomers used in the present invention, the alkyl part has 2 to 3 carbon atoms and contains a hydroxyalkyl (meth) acrylate [containing hydroxyalkyl acrylate and hydroxyalkyl methacrylate together. And expressed as hydroxyalkyl (meth) acrylate. The same applies below. ] (C) can be exemplified by 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate. Hydroxyalkyl (meth) acrylate (c) is contained in 2 to 6% by weight in a total of 100% by weight of ethylenically unsaturated monomers constituting (A), and may be used alone or in combination of two or more. it can. When the amount used is less than 2% by weight, the effect of improving the curved surface sticking property cannot be sufficiently obtained. .

  Among the radical polymerizable ethylenically unsaturated monomers used in the present invention, examples of the monomer (d) containing a carboxyl group include (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid. . These are contained in an amount of 0.5 to 5% by weight in a total of 100% by weight of the ethylenically unsaturated monomers constituting (A), and can be used alone or in combination of two or more. When the amount used is less than 0.5% by weight, the polymerization tends to become unstable, and the stability of the polymer itself is insufficient, and inconveniences such as sedimentation of the dispersion particles tend to occur. If the amount used exceeds 5% by weight, it is not preferable because it causes adverse effects such as a decrease in water resistance.

In addition to the monomers (a) to (d), other monomers copolymerizable with these can be used as necessary.
Examples of other copolymerizable monomers include alkyl acrylates having 1 to 3 carbon atoms in the alkyl group, alkyl methacrylates having 3 to 14 carbon atoms in the alkyl group, and 4 or more carbon atoms in the alkyl moiety. , Hydroxyalkyl (meth) acrylate having a hydroxyl group, or monomer (e) having a carbonyl group, such as acrolein, diacetone (meth) acrylamide, preferably vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinylmethyl) Ketone, vinyl ethyl ketone, vinyl isobutyl ketone, etc.), diacetone (meth) acrylate, acetonyl (meth) acrylate, acetoacetoxyethyl (meth) acrylate, diacetone (meth) acrylate, 2-hydroxypropyl (meth) acrylate-acetyl acetate, The Diol-1,4- (meth) acrylate-acetylacetate and the like, and a monomer (f) having two or more unsaturated bonds, for example, diallyl ester of phthalic acid (orthophthalic acid, isophthalic acid, terephthalic acid), methylenebis (Meth) acrylamide, 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc., and other simple units As the monomer (g), polyethylene glycol (meth) acrylate, glycidyl (meth) acrylate, mono- (2-hydroxylethyl-α-chloro (meth) acrylate) acid phosphate, vinyl blocked isocyanate, N-methylol ( (Meth) acrylamide, N-methylaminoethyl (meth) acrylate, N-tributylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, (meth) Examples include acrylamide, vinyl pyrrolidone, vinyl pyridine, vinyl acetate, vinyl propionate, styrene, (meth) acrylonitrile, butadiene, chloroprene and the like, and each can be used alone or in combination of two or more.

  As the emulsifier used when obtaining the aqueous resin composition dispersion (A) for the pressure-sensitive adhesive of the present invention, a reactive emulsifier, a non-reactive emulsifier, and the like can be used alone or in combination of two or more. In consideration of water resistance and the like, it is preferable to use a reactive emulsifier, but it is not limited thereto.

Examples of the reactive emulsifier include the following compounds.
Examples of anionic emulsifiers include nonylphenyl skeleton "Adekaria Soap SE-10N" manufactured by Asahi Denka Kogyo Co., Ltd. and "Aqualon HS-10, HS-20" manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Examples include “AQUALON KH-05, KH-10” manufactured by Kogyo Seiyaku Co., Ltd., “ADEKA rear soap SR-10N” manufactured by Asahi Denka Kogyo Co., Ltd., and “KAYARAD” manufactured by Nippon Kayaku Co., Ltd. having a phosphate ester skeleton.
Nonionic emulsifiers include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, sorbitan higher fatty acid esters, glycerin higher fatty acid esters and the like having an unsaturated double bond at the molecular terminal or in the middle. Asahi Denka Kogyo Co., Ltd. “Adekaria Soap NE-10”, Daiichi Kogyo Seiyaku Co., Ltd. “Aqualon RN-10, RN-20, RN-50”, Japan Emulsifier Stock Examples include “Antox NA-16” manufactured by the company.

Moreover, the following compounds can be illustrated as a non-reactive emulsifier.
Anionic emulsifiers include higher fatty acid salts such as sodium stearate, alkylaryl sulfonates such as sodium dodecylbenzene sulfonate, alkyl sulfate salts such as sodium lauryl sulfate, and polyoxyethylene alkyl such as sodium polyoxyethylene lauryl ether sulfate. Examples thereof include ether sulfate esters and polyoxyethylene alkylaryl ether sulfate salts such as sodium polyoxyethylene nonylphenyl ether sulfate.
Nonionic emulsifiers include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene alkyl phenyl ethers such as polyoxyethylene nonylphenyl ether, sorbitan higher fatty acid esters such as sorbitan monostearate, oleic acid Examples include glycerin higher fatty acid esters such as monoglyceride.
These are used in a ratio of 4 to 8 parts by weight based on 100 parts by weight of the total of ethylenically unsaturated monomers constituting (A). When the amount is less than 4 parts by weight, the polymerization becomes unstable and aggregates are likely to be generated.

  As the polymerization initiator used for obtaining the aqueous resin composition dispersion (A) for pressure-sensitive adhesives, water-soluble pyrolysis such as persulfates such as potassium persulfate and ammonium persulfate, azobis cation salts, or hydroxylated substances. A type polymerization catalyst or a redox polymerization catalyst can be used. The redox polymerization catalyst includes a combination of an organic peroxide such as t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide and a reducing agent such as Rongalite, sodium metabisulfite, or potassium persulfate or ammonium persulfate. And combinations of Rongalite and sodium thiosulfate, and combinations of hydrogen peroxide and ascorbic acid.

  Resin composition aqueous dispersion (A) is a mercaptan, thioglycol or β-mercapto as a chain transfer agent for controlling molecular weight and molecular weight distribution when an ethylenically unsaturated monomer is polymerized. Thiol compounds such as propionic acid can be used. The addition amount is preferably 0.01 to 10.0 parts by weight with respect to 100 parts by weight of the total amount of the ethylenically unsaturated monomers constituting (A).

Next, a method for polymerizing an ethylenically unsaturated monomer in an aqueous medium using an emulsifier and a polymerization initiator to obtain an aqueous resin composition dispersion (A) for pressure-sensitive adhesives will be described.
First, the ethylenically unsaturated monomer used in the present invention is mixed to obtain a uniform mixed solution. This mixed solution may be used for polymerization as it is, or a part or all of water and an emulsifier may be added and stirred to obtain an emulsion, which may be used for polymerization.
After preparing these mixed solutions or emulsions, polymerization is carried out in the presence of a polymerization initiator. As a method, the entire amount of the mixed solution or emulsion may be charged into a reaction vessel and polymerization may be started. After the polymerization is started by adding a part to the reaction vessel, it may be added in several divided portions, or after a part of the reaction vessel is started and the polymerization is started, the remainder may be continuously added dropwise, or water may be added in advance. If necessary, a part or the whole amount of the emulsifier may be charged into the reaction vessel, and the whole amount may be continuously dropped. When the polymerization is performed using the mixed solution, it is preferable to prepare the total amount of the emulsifier and a part or the total amount of water in the reaction vessel in advance.
As a method for adding the polymerization initiator, the whole amount may be charged in the reaction vessel in advance, or the whole amount may be added after the temperature rise, and several times after the polymerization is started after partly charged in the reaction vessel. It may be divided and added in portions, or after a part of the reaction vessel is charged and polymerization is started, the remainder may be continuously dropped, or the entire amount may be dropped continuously. When the polymerization initiator is dividedly added or continuously dropped, it may be added separately or continuously dropped into the reaction vessel alone, or may be dividedly added or continuously dropped in a mixed state with the mixed solution or emulsion. good. In addition, after adding a polymerization initiator by these methods, you may add a polymerization initiator once more in order to raise a reaction rate, or 2 times or more.
Thus, the resin composition aqueous dispersion (A) for pressure-sensitive adhesives of the present invention can be obtained.

<Adhesive resin composition aqueous dispersion (B)>
As the alkyl acrylate (a) having 4 to 14 carbon atoms in the alkyl group, those exemplified in the section of the resin composition aqueous dispersion (A) for pressure-sensitive adhesives can be used. Alkyl acrylates having a number of 4 to 12 are preferably used, and these are contained in an amount of 55 to 95% by weight in a total of 100% by weight of the ethylenically unsaturated monomers constituting (B), either alone or in combination of two or more. Can be used. If the amount used is less than 55% by weight, the adhesive strength is not sufficient, and if it exceeds 95% by weight, the effect of improving the curved surface sticking property cannot be sufficiently obtained.
As the monomer (d) containing a carboxyl group, those exemplified in the section of the resin composition aqueous dispersion (A) for pressure-sensitive adhesives can be used, and these are ethylenic polymers constituting (B). It is contained in an amount of 0.5 to 5% by weight in a total of 100% by weight of saturated monomers, and can be used alone or in combination of two or more. When the amount used is less than 0.5% by weight, the polymerization tends to become unstable, and the stability of the polymer itself is insufficient, so that inconveniences such as sedimentation of the dispersion particles tend to occur. If the amount used exceeds 5% by weight, it is not preferable because it causes adverse effects such as a decrease in water resistance.
In addition to the monomers (a) and (d), it is preferable to use other monomers copolymerizable with these in order to impart more preferable physical properties as an adhesive. Examples of other copolymerizable monomers include alkyl acrylates having 1 to 3 carbon atoms in the alkyl group, alkyl methacrylates having 1 to 14 carbon atoms in the alkyl group, hydroxy (meth) acrylates containing hydroxyl groups, And (e), (f), (g) and the like exemplified in the section of the aqueous resin composition dispersion (A) for the pressure-sensitive adhesive can be used, and each can be used alone or in combination of two or more. Can do.

As an emulsifier used when obtaining the resin composition aqueous dispersion (B) for pressure-sensitive adhesive, those exemplified in the section of the resin composition aqueous dispersion (A) for pressure-sensitive adhesive can be used.
These are used in a ratio of 1.5 to 3 parts by weight based on 100 parts by weight of the total of ethylenically unsaturated monomers constituting (B). If the amount is less than 1.5 parts by weight, the polymerization becomes unstable and aggregates tend to be generated. If the amount is more than 3 parts by weight, the adhesive strength is lowered and the water resistance tends to be lowered.

As the polymerization initiator used when obtaining the resin composition aqueous dispersion (B), those exemplified in the section of the resin composition aqueous dispersion (A) can be used.
The aqueous resin composition dispersion for pressure-sensitive adhesives (B) uses the chain transfer agent exemplified in the section of the aqueous dispersion for resin composition for pressure-sensitive adhesives (A) when polymerizing the ethylenically unsaturated monomer. I can do things.
For a method of polymerizing an ethylenically unsaturated monomer in an aqueous medium using an emulsifier and a polymerization initiator to obtain an aqueous resin composition dispersion (B) for an adhesive, the aqueous resin composition dispersion for an adhesive is described below. The method described in the section of the body (A) can be used.
Thus, the resin composition aqueous dispersion (B) for the pressure-sensitive adhesive of the present invention can be obtained.

The obtained resin composition aqueous dispersion for pressure-sensitive adhesive (A) and the resin composition aqueous dispersion for pressure-sensitive adhesive (B) have a solid content weight ratio of (A) / (B) of 5/95 to 30/70. The aqueous pressure-sensitive adhesive composition of the present invention is obtained by mixing and blending so that the ratio becomes (A) / (B) = 10/90 to 20/80.
When the solid content weight ratio of (A) is less than 5% by weight, the effect of improving the adhesion strength and curved surface sticking property cannot be sufficiently obtained, and when the solid content weight ratio of (A) exceeds 30% by weight, the adhesive strength and Since curved surface sticking property tends to decrease, it is not preferable.

The aqueous pressure-sensitive adhesive composition of the present invention mainly comprises the above-mentioned pressure-sensitive adhesive resin composition aqueous dispersion (A) and the pressure-sensitive adhesive resin composition aqueous dispersion (B). Accordingly, a polymer of an ethylenically unsaturated monomer other than (A) and (B) specified in the present invention may be added, and a suitable tackifier, for example, An appropriate amount of rosin resin, phenol resin, polyterpene, acetylene resin, petroleum hydrocarbon resin, ethylene vinyl acetate copolymer, synthetic rubber, natural rubber, or the like can be added. Furthermore, a viscosity modifier, an antifoaming agent, a leveling agent, a plasticizer, a filler, a neutralizing agent, a colorant, a silane coupling agent, an antiseptic, and the like may be added.
Furthermore, in order to cross-link the resin composition aqueous dispersion for pressure-sensitive adhesive in the aqueous pressure-sensitive adhesive composition of the present invention between particles, an arbitrary cross-linking agent may be blended, for example, as an ethylenically unsaturated monomer component. When a monomer having a hydroxyl group is used, an isocyanate compound, an alkoxide compound such as titanium or zirconium can be used, and when a monomer having a carbonyl group is used, amines, hydrazide compounds, etc. Can be used.

The pressure-sensitive adhesive composition of the present invention is applied onto a paper or plastic film substrate or a release sheet by various coating apparatuses such as a comma coater, a reverse coater, a slot die coater, a lip coater, a gravure chamber coater, and a curtain coater. By drying, various adhesive coated products such as an adhesive sheet and an adhesive label can be obtained. It is preferable to dry at 80 ° C. to 120 ° C. after applying the pressure-sensitive adhesive composition to paper or the like. When the drying temperature is 80 ° C. or lower, it is difficult to dry, and it takes a long time to dry. On the other hand, drying at a temperature higher than 120 ° C. is not preferable because it causes thermal deterioration of the substrate or the peelable sheet.
When the pressure-sensitive adhesive composition is applied on a paper or plastic film substrate, it is bonded to the peelable sheet after drying. When the pressure-sensitive adhesive composition is applied to the peelable sheet, the paper or plastic is dried after drying. By adhering to the film substrate, various adhesive coated products can be obtained by either method.
The peelable sheet is also called a separator, and is formed by peeling at least one surface of paper or a plastic film. A conventionally known release treatment agent can be used.

  The present invention will be described below with reference to examples, but is not limited thereto. In the examples, “part” means “part by weight” and “%” means “% by weight”.

(Production Example-1)
82.5 parts of 2-ethylhexyl acrylate, 11 parts of methyl methacrylate, 3 parts of 2-hydroxyethyl methacrylate, 3.5 parts of acrylic acid, thioglycolic acid as a chain transfer agent for 100 parts of these all ethylenically unsaturated monomers Add 0.02 parts of octyl, 5 parts of "Aqualon KH-10" manufactured by Daiichi Kogyo Seiyaku Co., Ltd. as a reactive ammonia-neutralized anionic emulsifier in 30.5 parts of deionized water and stir. An emulsion was obtained and placed in a dropping funnel.
A four-necked flask equipped with a stirrer, condenser, thermometer and dropping funnel was charged with 57 parts of deionized water, the inside of the flask was replaced with nitrogen gas, and the internal temperature was raised to 80 ° C. while stirring. 0.1 part of 3% potassium persulfate aqueous solution was added as a solid content. After 5 minutes, the dropping of the emulsion was started from the dropping funnel, and in parallel, 0.3 part of 3% potassium persulfate aqueous solution was added dropwise from another dropping port over 3 hours.
While maintaining the internal temperature at 80 ° C., 30 minutes after the completion of dropwise addition of the above emulsion and 3% aqueous potassium persulfate solution, 0.06 parts were divided into two portions each containing 30% aqueous 3% potassium persulfate solution every 30 minutes. Added.
The mixture was further aged at 80 ° C. for 2 hours with stirring and then cooled to obtain an aqueous resin composition dispersion (A-1) for pressure-sensitive adhesive having a solid content of 50%.

(Production Example-2)
2-ethylhexyl acrylate 39.5 parts, butyl acrylate 40 parts, methyl methacrylate 13 parts, 2-hydroxyethyl acrylate 5 parts, acrylic acid 2.5 parts, thioglycol with respect to 100 parts of these all ethylenically unsaturated monomers A solution prepared by dissolving 0.02 part of octyl acid and 5 parts of “AQUALON KH-10” in 30.5 parts of deionized water was added and stirred to obtain an emulsion. Thereafter, an adhesive resin composition aqueous dispersion (A-2) having a solid content of 50% was obtained in the same manner as in Production Example-1.

(Production Example-3)
19 parts of 2-ethylhexyl acrylate, 60 parts of butyl acrylate, 14 parts of methyl methacrylate, 4 parts of 2-hydroxyethyl methacrylate, 3 parts of acrylic acid, and octyl thioglycolate with respect to 100 parts of all ethylenically unsaturated monomers. 03 parts and 5 parts of "Aqualon KH-10" dissolved in 30.5 parts of deionized water were added and stirred to obtain an emulsion. Thereafter, a resin composition aqueous dispersion (A-3) having a solid content of 50% was obtained in the same manner as in Production Example-1.

(Production Example-4)
2-ethylhexyl acrylate 84.5 parts, methyl methacrylate 11 parts, 2-hydroxyethyl methacrylate 1 part, acrylic acid 3.5 parts, octyl thioglycolate 0.02 with respect to 100 parts of these all ethylenically unsaturated monomers And 5 parts of “AQUALON KH-10” dissolved in 30.5 parts of deionized water were added and stirred to obtain an emulsion. Thereafter, an adhesive resin composition aqueous dispersion (A-4) having a solid content of 50% was obtained in the same manner as in Production Example-1.

(Production Example-5)
2-ethylhexyl acrylate 86.5 parts, methyl methacrylate 7 parts, 2-hydroxyethyl methacrylate 3 parts, acrylic acid 3.5 parts, octyl thioglycolate 0.02 with respect to 100 parts of these all ethylenically unsaturated monomers And 5 parts of “AQUALON KH-10” dissolved in 30.5 parts of deionized water were added and stirred to obtain an emulsion. Thereafter, a resin composition aqueous dispersion (A-5) having a solid content of 50% was obtained in the same manner as in Production Example-1.

(Production Example-6)
29.8 parts of “AQUALON KH-10” are added to 89.8 parts of 2-ethylhexyl acrylate, 8 parts of methyl methacrylate, 2 parts of acrylic acid, 0.2 part of diacetone acrylamide and 100 parts of these all ethylenically unsaturated monomers. What was dissolved in 30.5 parts of deionized water was added and stirred to obtain an emulsion, which was placed in a dropping funnel.
A four-necked flask equipped with a stirrer, a condenser, a thermometer and the above dropping funnel was charged with 54 parts of deionized water and 0.1 part of “AQUALON KH-10”, and the inside of the flask was replaced with nitrogen gas. While stirring, the internal temperature was raised to 80 ° C., and 0.1 part of a 3% potassium persulfate aqueous solution was added as a solid content. After 5 minutes, the dropping of the emulsion was started from the dropping funnel, and in parallel, 0.3 part of 3% potassium persulfate aqueous solution was added dropwise from another dropping port over 3 hours.
While maintaining the internal temperature at 80 ° C., 30 minutes after the completion of dropwise addition of the above emulsion and 3% aqueous potassium persulfate solution, 0.06 parts were divided into two portions each containing 30% aqueous 3% potassium persulfate solution every 30 minutes. Added.
The mixture was further aged at 80 ° C. for 2 hours with stirring and then cooled to obtain an aqueous resin composition dispersion (B-1) for pressure-sensitive adhesive having a solid content of 50%.

(Production Example-7)
“Aqualon” is used for 52.3 parts of 2-ethylhexyl acrylate, 40 parts of butyl acrylate, 6 parts of methyl methacrylate, 1.5 parts of acrylic acid, 0.2 part of diacetone acrylamide and 100 parts of all ethylenically unsaturated monomers. A solution obtained by dissolving 2 parts of KH-10 in 30.5 parts of deionized water was added and stirred to obtain an emulsion, which was placed in a dropping funnel.
Thereafter, a resin composition aqueous dispersion (B-2) having a solid content of 50% was obtained in the same manner as in Production Example-6.

(Production Example-8)
2-ethylhexyl acrylate 88.92 parts, methyl methacrylate 8.36 parts, 2-hydroxyethyl methacrylate 0.36 parts, acrylic acid 2.18 parts, diacetone acrylamide 0.18 parts, these all ethylenically unsaturated monomers An emulsion obtained by adding 0.0024 parts octyl thioglycolate and 2.36 parts “AQUALON KH-10” dissolved in 30.5 parts deionized water as a chain transfer agent to 100 parts and stirring. This was put into a dropping funnel.
A four-necked flask equipped with a stirrer, a condenser, a thermometer and the above dropping funnel was charged with 57 parts of deionized water and 0.09 part of “AQUALON KH-10”, and the inside of the flask was replaced with nitrogen gas. While stirring, the internal temperature was raised to 80 ° C., and 0.1 part of a 3% potassium persulfate aqueous solution was added as a solid content. After 5 minutes, the dropping of the emulsion was started from the dropping funnel, and in parallel, 0.3 part of 3% potassium persulfate aqueous solution was added dropwise from another dropping port over 3 hours.
While maintaining the internal temperature at 80 ° C., 30 minutes after the completion of dropwise addition of the above emulsion and 3% aqueous potassium persulfate solution, 0.06 parts were divided into two portions each containing 30% aqueous 3% potassium persulfate solution every 30 minutes. Added.
Further, the mixture was aged at 80 ° C. for 2 hours with stirring, and then cooled to obtain an aqueous resin composition dispersion for pressure-sensitive adhesive (C-1) having a solid content of 50%.

  Table 1 shows the composition of the aqueous resin composition dispersion for pressure-sensitive adhesives obtained in each production example.

(Example-1)
12 parts by solid content of (A-1) obtained in Production Example-1 as a resin composition aqueous dispersion (A) for pressure-sensitive adhesive, and Production Example as a resin composition aqueous dispersion (B) for pressure-sensitive adhesive (B-1) obtained in No. 6 was mixed with 88 parts of solid content, adjusted to pH = 7.5 with ammonia water, added with an antifoaming agent, leveling agent, preservative, and further rosin-based tackified. Arakawa Chemical Co., Ltd. "Superester E-720" (solid content 50%) as a solid, 15 parts as a solid, and 6% adipic acid dihydrazide aqueous solution as a crosslinking agent as a solid, 0.2 parts as a resin, and viscosity The viscosity was adjusted to 3000 mPa · s (with a BL type viscometer, using a # 4 rotor, measured at 60 rpm) with an adjusting agent to obtain an aqueous pressure-sensitive adhesive composition.
This was coated on a release paper with a comma coater so that the dry coating amount was 20 g / m ² , dried in a drying oven at 100 ° C. for 40 seconds, laminated with a PET film having a thickness of 50 μm, wound up, and adhered. An agent coated product was obtained, and the performance as an adhesive coated product was evaluated by the test method described later. The results are shown in Table 2.

(Examples 2-7, Comparative Examples-1-7)
Resin composition for pressure-sensitive adhesives Aqueous pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that the types and mixing ratios of aqueous dispersions (A) and (B) were changed as shown in Table 2, and pressure-sensitive adhesive coating The performance as a work was evaluated. In addition, about the resin composition aqueous dispersion for adhesives (C-1) obtained by manufacture example-8, it was the same as Example 1 except having used 100 parts as solid content independently. The product was obtained, and the performance as an adhesive coated product was evaluated.

[Test method]
1) Adhesive strength The adhesive coated product is cut into a 25 mm wide strip, the release paper is peeled off, and is attached to a 2 mm thick polyethylene plate, reciprocated once with a 2 kg roll, and then in a 23 ° C. atmosphere for 24 hours. I left it alone. After a predetermined time, the adhesive strength was measured when the coated material was peeled in the 180 ° direction at a speed of 300 mm / min in an atmosphere of 23 ° C.

2) Curved surface sticking property The pressure-sensitive adhesive coated material was cut into a size of 20 mm in width and 15 mm in length, the release paper was peeled off, and pasted around a polyethylene rod having a length of 30 cm and a diameter of 10 mm. As the direction of application, the width direction (longitudinal direction) of the coated sample was made parallel to the length direction of the polyethylene rod. After pasting, it was strongly pressure-bonded with a finger and allowed to stand in a 23 ° C. atmosphere for 7 days. After a predetermined period of time, it was visually observed whether the sample was peeled off.
○: No peeling.
(Triangle | delta): The edge part of a sample has peeled.
X: The entire surface was peeled off and the substrate was flat.

As shown in Comparative Examples-1 and 2, the resin composition aqueous dispersion for pressure-sensitive adhesive (A) and the resin composition aqueous dispersion for pressure-sensitive adhesive (B) were not used in combination, and each dispersion was used alone. When the pressure-sensitive adhesive composition is prepared, the adhesive strength to the polyethylene adherend and the curved surface sticking property are poor. As shown in Comparative Example-3, when the amount of the ethylenically unsaturated monomer (c) used in the resin composition aqueous dispersion (A) is too smaller than the quantity specified in the present invention, curved surface pasting It is inferior. As shown in Comparative Example-4, the same applies when the amount of the ethylenically unsaturated monomer (b) used in the adhesive resin composition aqueous dispersion (A) is too smaller than the amount specified in the present invention. Inferior to curved surfaces. Further, as shown in Comparative Example-5, when the blending ratio of the resin composition aqueous dispersion for pressure-sensitive adhesive (A) is too smaller than the blending ratio specified in the present invention, the adhesive force and the curved surface sticking property are slightly improved. However, the results obtained in the examples of the present invention are not as good. Further, as shown in Comparative Example-6, when the blending ratio of the aqueous resin composition for pressure-sensitive adhesive (A) is too larger than the blending ratio specified in the present invention, the adhesive force and the curved surface sticking property are similarly applied. Falls short of the results obtained in the examples.
Furthermore, in Comparative Example-7, each monomer and chain transfer agent as a whole of the mixture in which the solid content ratio of (A-1) / (B-1) in Example-1 is 12/88. The examples show that the amount of the emulsifier is averaged and polymerized as a single resin composition aqueous dispersion for a pressure-sensitive adhesive, but contrary to Example-1, the adhesive strength and the curved surface sticking property are inferior. Yes.

On the other hand, in the examples in the present invention, it shows high adhesive strength and excellent curved surface sticking property, and the pressure-sensitive adhesive coated product using the water-based pressure-sensitive adhesive obtained by the present invention is conventionally used as a water-based pressure-sensitive adhesive. It can be preferably used for polyolefin adherends such as polyethylene, which has been difficult, and since it has good curved surface sticking properties, it can also be used favorably for adherends having curved shapes. .
Although the mechanism is not clear, especially as seen in the results of Comparative Example-7, even if the average composition as a whole is the same composition, the effect of the present invention is obtained when a single resin composition is used. In the pressure-sensitive adhesive coating film obtained from the pressure-sensitive adhesive composition of the present invention, the dispersion particles having different compositions are present independently without being completely complexed due to the fact that they are not obtained. It is inferred that the above-described effects are exhibited by the interaction between particles having different compositions.

Claims (2)

Alkyl acrylate having 4 to 14 carbon atoms (a) 70 to 87.5% by weight, alkyl methacrylate having 1 to 2 carbon atoms (b) 10 to 15% by weight, carbon in the alkyl part A radical containing 2 to 6% by weight of a hydroxyalkyl (meth) acrylate (c) containing a hydroxyl group and 0.5 to 5% by weight of a monomer (d) containing a carboxyl group. A polymerizable ethylenically unsaturated monomer is polymerized in an aqueous medium using 4 to 8 parts by weight of an emulsifier and a polymerization initiator with respect to 100 parts by weight of the total amount of the ethylenically unsaturated monomer. Aqueous resin composition aqueous dispersion (A), alkyl acrylate (a) having an alkyl group having 4 to 14 carbon atoms, 55 to 95% by weight, monomer containing a carboxyl group (d) 0.5 ~ 5% by weight Having an ethylenically unsaturated monomer capable of radical polymerization in an aqueous medium using an emulsifier and a polymerization initiator in an amount of 1.5 to 3 parts by weight based on 100 parts by weight of the total amount of the ethylenically unsaturated monomer. Polymeric adhesive resin composition aqueous dispersion (B) obtained by polymerization, containing (A) / (B) at a solid content weight ratio of 5/95 to 30/70, and further containing a crosslinking agent aqueous pressure-sensitive adhesive composition characterized by containing. Alkyl acrylate (a) 70 to 87.5% by weight having 4 to 14 carbon atoms in the alkyl group, 10 to 15% by weight alkyl methacrylate (b) having 1 to 2 carbon atoms in the alkyl group, carbon in the alkyl part Radical containing 2 to 6% by weight of a hydroxyalkyl (meth) acrylate (c) having a hydroxyl group and 2 to 3% by weight of a monomer (d) containing a carboxyl group A polymerizable ethylenically unsaturated monomer is polymerized in an aqueous medium using 4 to 8 parts by weight of an emulsifier and a polymerization initiator with respect to 100 parts by weight of the total amount of the ethylenically unsaturated monomer. Resin composition aqueous dispersion for pressure-sensitive adhesive (A), alkyl acrylate (a) having an alkyl group having 4 to 14 carbon atoms, 55 to 95% by weight, monomer (d) 0.5 containing a carboxyl group Contains ~ 5% by weight Radically polymerizable ethylenically unsaturated monomer in an aqueous medium using 1.5 to 3 parts by weight of an emulsifier and a polymerization initiator with respect to 100 parts by weight of the total amount of the ethylenically unsaturated monomer. The aqueous resin composition for pressure-sensitive adhesives (B) obtained by polymerization is used at a ratio of (A) / (B) solid content of 5/95 to 30/70 , and a crosslinking agent is further blended. A method for producing an aqueous pressure-sensitive adhesive composition , which comprises mixing.