JPS60190484A - Pressure-sensitive adhesive composition - Google Patents

Abstract

PURPOSE:The titled composition useful as a pressure-sensitive adhesive tape, sheet, etc., having improved cohesive force, bond strength, and resilience resistance, obtained by adding a polyvalent metal compound to an aqueous dispersion of a specific polymer. CONSTITUTION:(A) An aqueous dispersion of a polymer containing >=50wt% of the polymer having a monomer composition comprising (A) 0.2-20wt% unsaturated carboxylic acid, (B) 50-99.8wt% acrylic alkyl ester containing 4-12C alkyl, and (C) 0-49.8wt% another copolymerizable unsaturated monomer is blended with >=0.1 equivalent based on the carboxyl group of the polymer of a polyvalent metal (preferably zinc) compound, to give the desired composition. The aqueous dispersion of the polymer is obtained by subjecting individually a monomer component having the maximum unsaturated carboxylic acid content of 2-50wt% unsaturated carboxylic acid content, and a monomer component having the minimum unsaturated carboxylic acid content >=2wt% smaller unsaturated carboxylic acid content than the monomer component to emulsion polymerization, followed by blending, or subjecting the monomers to successive emulsion polymerization, followed by blending, or by blending them.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-dispersed pressure-sensitive adhesive composition that has excellent cohesive strength, adhesive strength, and repulsion resistance.

Currently, pressure-sensitive adhesives include natural rubber-based, synthetic rubber-based, and acrylic-based adhesives, and are used in the form of tapes, sheets, etc. for many purposes. Among these, acrylic pressure-sensitive adhesives have become widely popular in recent years due to their excellent adhesiveness and durability. Acrylic pressure-sensitive adhesives include organic solvent solution type and water dispersion type, but water dispersion type is preferred from the viewpoint of environmental hygiene and resource saving. The main component of acrylic pressure-sensitive adhesives is a polymer of acrylic acid ester that is sticky at room temperature, but such a polymer alone does not have sufficient cohesive force, so it cannot be used as a pressure-sensitive adhesive. You will only get something unsatisfactory.

For this reason, unsaturated monomers such as unsaturated carboxylic acids, vinyl acetate, styrene, acrylonitrile, methacrylic acid esters, etc., which do not have particular tackiness at room temperature but have high cohesive strength, or which have tackiness at room temperature. It has been carried out to copolymerize acrylic esters other than the acrylic esters that yield polymers with acrylic esters that yield polymers that are sticky at room temperature. In order to obtain a water-dispersed acrylic pressure-sensitive adhesive, such copolymerization is usually carried out by emulsion polymerization, so a polymer with a higher molecular weight can be obtained than by solution polymerization using an organic solvent, etc. It is known that it can be made into a pressure sensitive adhesive with high cohesive strength. However, pressure-sensitive adhesive tapes or sheets obtained using the acrylic water-dispersed pressure-sensitive adhesive thus obtained can be applied to curved surfaces of adherends, such as plastic, glass, ceramic, or metal cylindrical containers. When the tape or sheet is bonded in a bent state to a curved surface such as a tape or sheet, a repulsive force acts on the tape or sheet, which often causes the tape or sheet to peel off from its edges. This phenomenon becomes extremely noticeable at relatively high temperatures and is hardly of practical use. This phenomenon is caused by the fact that the pressure-sensitive adhesive still lacks cohesive strength and adhesive strength. Therefore, in order to obtain the ability to adhere a tape or sheet to a curved surface while resisting the above-mentioned repulsion force, that is, so-called repulsion resistance, pressure-sensitive adhesives must combine high cohesive strength and high adhesive strength. It is essential to have one.

This cohesive force of pressure-sensitive adhesives is also important when processing pressure-sensitive adhesive tapes and sheets made using this adhesive.In other words, pressure-sensitive adhesive tapes are usually first prepared in a wide state. After being made to a length of about 1 meter, for example, it goes through a process of being cut at high speed to a width that can be used for practical purposes, for example, about a few pieces of steel.
At this time, if the cohesive force of the pressure-sensitive adhesive is low, the pressure-sensitive adhesive will adhere to the surface of the cutter used for cutting, and the efficiency of the cutting process will be extremely reduced. In addition, pressure-sensitive adhesive sheets are often used after being punched out into letters or other various shapes at the final use stage, and immediately after the punching process, unnecessary parts of the sheet are continuously removed at high speed. However, if the cohesive strength of the pressure-sensitive adhesive is low at this time, the pressure-sensitive adhesive separated during the punching process may immediately become integrated afterwards, and the necessary Parts may be removed or continuous unnecessary parts may be broken, resulting in an extremely low efficiency of this process.

As mentioned above, the cohesive force of a pressure sensitive adhesive plays an extremely important role not only in its longest use stage, but also in the process of making pressure sensitive adhesive tapes and sheets.

Therefore, in order to increase the cohesive force of the pressure-sensitive adhesive, for example, when emulsion polymerizing the unsaturated monomers mentioned above,
Copolymerizing internal crosslinking agents such as polyhydric alcohol di- or tri(meth)acrylate or divinylbenzene,
Attempts have been made to add external crosslinking agents such as melamine compounds, epoxy compounds, or polyvalent metal salts to aqueous dispersions of polymers obtained by emulsion polymerization. However, although the cohesive force itself can be increased by such a conventionally known method, the adhesive force is greatly reduced, making it difficult to obtain sufficient repulsion resistance as described above.

Considering this situation, the present inventors added a polyvalent metal compound to a specific aqueous polymer dispersion, which showed excellent processability and high cohesive strength when made into pressure-sensitive adhesive tapes and sheets. The present invention was completed based on the discovery that a water-dispersed pressure-sensitive adhesive composition having high adhesive strength and excellent repulsion resistance can be obtained.

The present invention also includes a single phase polymer aqueous dispersion (A,) which is not represented by the following (T, ).
and a polyvalent metal compound (B) as essential components, wherein the pressure-sensitive adhesive composition contains an aqueous polymer dispersion (A, contains 5 polymers
The polyvalent metal compound (B) accounts for 0 weight percent or more, and the polyvalent metal compound (B) accounts for (], 1% with respect to the carboxyl groups in the total polymer.
The present invention provides a pressure-sensitive adhesive composition characterized in that the ratio is equal to or more than the equivalent amount.

(Note) (r) The content of unsaturated carboxylic acid mW (a) in the monomer component system containing the largest amount of unsaturated carboxylic acid (a) is 2 to 50% by weight, and Acid (a
J4j, - in which the difference in the content of the unsaturated carboxylic acid (a) between the monomer component system with the highest content and the Kuramayari component system with the lowest content of ) is 2% by weight or more. 2 of the aqueous polymer dispersion obtained by individually emulsion polymerizing each of the body component systems.
Mixing one or more types of polymer aqueous dispersion obtained by mixing two or more species (a) or a polymer aqueous dispersion obtained by successive emulsification of each of these monomer components. or the polymer aqueous dispersion obtained by mixing the polymer aqueous dispersion (a) or the polymer aqueous dispersion (c) obtained by mixing the polymer aqueous dispersion (b). and the monomer composition of the total polymer contained is an unsaturated carboxylic acid (a) 02 to 20% by weight, and an acrylic acid alkyl ester (b) 50 to 998, in which the alkyl group has 4 to 12 carbon atoms. Copolymerizable OT-capable unsaturated single Ff substance (c) O~49.8% heavy weight (however, a
), (b) and (C) is 100% by weight. )
An aqueous polymer dispersion (A).

In the present invention, the vesicles) locarvone d(a) used in obtaining the aqueous polymer dispersion (A) specified in item (I) above include acrylic acid, methacrylic acid, crotonic acid, etc. Unsaturated basic acids; examples include unsaturated dibasic acids such as maleic acid, fumaric acid, itaconic acid, and citraconic acid, and their monoesters, and one or more of these can be used. . In the monomer composition of all the polymers contained in the aqueous polymer dispersion (A), the proportion of the unsaturated carboxylic acid (a) is 0.2 to 20 wt.
Must be %. If the leaves are less than 0.2% by weight, high cohesion and adhesive strength cannot be obtained when used as a pressure-sensitive adhesive;
If the current exceeds 20% by weight, the adhesive strength will decrease.

Examples of acrylic acid alkyl esters (b) in which the alkyl group has 4 to 12 carbon atoms include butyl acrylate, isobutyl acrylate, 5ec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, Hexyl acrylate, cyclohexyl acrylate, heptyl acrylate, octyl acrylate,
Examples include 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, and dodecyl acrylate, and 1'PM or two or more of these alkyl acrylates can be used. In the monomer composition of all the polymers contained in the aqueous polymer dispersion (A), the proportion of the a9-acrylic acid alkyl ester (b) is 50 to 50.
It needs to be 99.8%. If the amount is less than 50% by weight, the adhesive strength and durability of the pressure-sensitive adhesive composition will be reduced, and if it exceeds 998% by weight, it will be less than 50% by weight. It is not possible to obtain a pressure sensitive adhesive with cohesive strength.

Examples of other copolymerizable unsaturated monomers (C) include aliphatic vesicular hydrocarbons such as ethylene and butadiene;
Halogen-substituted aliphatic unsaturated hydrocarbons such as vinyl chloride; Aromatic vesicles such as styrene, α-methylstyrene, and divinylbenzene; Vinyl esters such as vinegar and vinyl; Vinyl ethers; Allyl alcohol esters with organic acids and ethers with various alcohols; unsaturated cyanide compounds such as acrylonitrile; unsaturated amide compounds such as acrylamide; acrylic acid alkyl esters with an alkyl group other than 4 to 12 carbon atoms; Acrylic acid aryl esters; various esters of unsaturated oleo-base carboxylic 10-acids such as methacrylic acid and crotonic acid; various diesters of unsaturated dibasic carboxylic acids such as maleic acid and fumar f'ff; It is possible to use two or more types of one type selected from these types. Polymer aqueous dispersion #(A)
In the mass composition of all the polymers contained in the vesicles,
The proportion of the d-body (C) (/i) must be 0 to 498% by weight. If it exceeds 49.8% by weight, the adhesive strength of the pressure-sensitive adhesive composition may decrease and the durability may deteriorate. descend,
Vesicle 1] Among the single adhesion bodies (c), for example, polyalcohol di- or tri(meth)acrylates, divinylbenzene, etc. have two or more radical polymerizable i+T vinyl groups in one molecule. Unsaturated monomers generally act as internal cross-linking agents,7 and their use tends to decrease, although the resulting pressure-sensitive adhesive exhibits relatively high cohesive strength when used in large amounts. The amount is preferably 2% or less based on the total amount of all monomer components. The polymer aqueous dispersion (a) obtained by mixing two or more of the aqueous polymer dispersions obtained by emulsion polymerization of (a) or each of the monomer components of the above are sequentially emulsion polymerized. One or two of the aqueous polymer dispersions obtained by
Seed 1'J, a polymer aqueous dispersion (b) obtained by mixing the above, or a polymer aqueous dispersion (b) obtained by mixing the aqueous polymer dispersion (a) and the aqueous polymer dispersion (b). The monomer component system used for single emulsion polymerization or sequential emulsion polymerization must satisfy the following conditions (i) and (ii): .

(1) The content of unsaturated carboxylic acid (a) in the monomer component system containing the largest amount of unsaturated carboxylic acid (a) is 2 to
It is 50%.

(ii) The difference in the content of unsaturated carboxylic acid (a) in the monomer component system with the highest content of unsaturated carboxylic acid (a) and the monomer component system with the lowest content is determined by two vehicle inspections. % or more of the monomer hQ subsystem is required. In condition (1), if the amount of unsaturated carboxylic acid (a) is less than 1% by weight, a pressure-sensitive adhesive with binding and binding power cannot be obtained, and if it exceeds 500 parts by weight, emulsion polymerization is difficult. becomes. Further, in condition (ii'), if the difference in the content of unsaturated carboxylic acid (a) is less than 2% by weight, the cohesive force and adhesive force will be poor.

Polymer aqueous dispersion in the present invention/f! In the emulsion polymerization to obtain (A), conventionally known emulsifiers can be used. Examples of anionic emulsifiers include fatty acid salts, higher alcohol sulfate ester salts, alkylbenzene sulfonates, alkylnaphthanone sulfonates, naphthalene sulfonic acid formalin condensates, dialkyl sulfosuccinate ester salts, polyoxyethylene alkyl sulfosuccinate monoester salts, polyoxyethylene alkyl sulfate salt,
polyoxyethylene alkylaryl sulfate salt,
Polyoxyethylene alkyl phosphate ester salt, etc.: polyoxyethylene alkyl ether, polyoxyethylene alkyl 71J-lether, polyoxyethylene alkyl 71J-lether as a nonionic emulsifier
Examples include polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxy-13-diethylene sorbitan fatty acid ester, oxyethylene oxypropylene block copolymer, and fatty acid monoglyceride. One or more emulsifiers selected from the group of emulsifiers can be effectively used, and the amount used is 0.1 to 0.01 to
It is preferable to set it in the range of 10 heavy weights. Note that, if necessary, protective colloids can be used alone or together with an emulsifier, and furthermore, depending on the case, it is also possible to obtain an aqueous polymer dispersion without using these emulsifiers or protective colloids at all.

Examples of polymerization catalysts for emulsion polymerization of unsaturated monomers include inorganic peroxides such as ammonium persulfate and hydrogen peroxide; organic peroxides such as t-butylnohydroboroxide; and other radical-generating materials. A polymerization initiator or the like can be used, and the amount used is 001.about.3 parts by weight, preferably 0.1 to 1 part by weight, per 100 parts by weight of the unsaturated monomer.

When using peroxides, reducing agents such as soluble 14-sulfites or ascorbic acid or sulfuric acid may be added if it is necessary to increase the polymerization rate or lower the reaction temperature.
A redox system can be created by combining a metal compound such as iron that generates heavy metal range ions in water with a peroxide.

The temperature for emulsion polymerization is appropriately selected depending on the type and composition of the vesicle polymer, the type of polymerization catalyst, etc., but is usually 0 to 100%.
℃ range.

The amount of water during emulsion polymerization is usually 300 to 50 parts by weight per 100 parts by weight of the unsaturated monomer.

The aqueous dispersion of the polymer of the present invention (A
, ) is usually acidic, but in the present invention, it can be made as it is or by adding a volatile base such as ammonia before or after mixing with the polyvalent metal compound (13) to make it neutral or It can be used after being made alkaline.

The aqueous polymer dispersion (-A-) is used in such a proportion that the polymer contained in the dispersion CA, ) is 50% by weight or more based on the total polymer in the pressure-sensitive adhesive composition of the present invention. Ru. 15
If the amount is less than 0% by weight, the adhesive force, cohesive force, repulsion resistance, etc. of the pressure sensitive adhesive will be unsatisfactory.

Next, as the polyvalent metal compound (B) in the present invention,
One or more selected from the group consisting of polyvalent metal salts, complexes, chelates, hydroxides, and oxides can be effectively used. Examples of polyvalent metals that form such polyvalent metal compounds and are suitable for the present invention include zinc, calcium, magnesium, aluminum, etc. Among these polyvalent metals, zinc is particularly preferred.

The ratio of the polyvalent metal compound (B) used is 091% relative to the carboxyl groups in the total polymer contained in the pressure sensitive adhesive composition. If the amount used is less than 0.1% equivalent, optical performance will not be exhibited.

The optimum amount to be used within this range is appropriately selected depending on the type of monomer component used to obtain the aqueous polymer dispersion (N) and the type of polyvalent metal compound (B).

The polyvalent metal compound (B) may be added to the aqueous polymer dispersion (A) of the present invention in the form of a dispersion in water using a dispersant, a form dissolved in water, or a solid state. I can do it. When the polyvalent metal compound (B) does not substantially dissociate or dissolve in water, it is preferably added in the form of a dispersion in water in order to more strongly exhibit the effects of the present invention. When using the polyvalent metal compound (B) in the form of dispersion in water, any dispersant can be used as long as it can disperse solid particles in water, such as sodium polyacrylate, naphthalene sulfonic acid, etc. One or more of the following block copolymers (1), (2), and (3) can be effectively used, such as a soda-formalin condensate, a diinobutylene-maleic acid copolymer, and the like. The leaves of the dispersant used when obtaining an aqueous dispersion of the polyvalent metal compound (B) using the dispersant are determined according to the types of the dispersant and the polyvalent metal compound (B) and the water dispersion. It changes depending on the concentration of the polyvalent metal compound (B) and cannot be specified, but it is usually 0 for the polyvalent metal compound (B).
．． It is determined as appropriate in the range of 1 to 20% debt.

Block copolymer (1) polyalkylene glycol mono(meth)allyl ether monomer represented by 17- (However, in the formula, R1 and R may each have hydrogen or methyl bonded randomly.) One or more monomers selected from acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid and their salts, and if necessary, a monomer copolymerizable with these monomers. obtained by copolymerizing polymers using a polymerization initiator.

Block copolymer (2) General formula % Formula % (4 (However, in the formula, R3 and Melon each represent hydrogen or a methyl group, 0 represents an integer from 1 to 100, = 18-th, +0CHCH, - ), some of which may have repeating structural units randomly bonded to each other. It is obtained by copolymerizing one or more monomers selected from itaconic acid and salts thereof, and if necessary, a monomer copolymerizable with these monomers using a polymerization initiator. Something.

Block copolymer (3) General formula % Formula % (wherein p represents an integer of 1 to 4, q and r each independently represent 0 or an integer of 1 to 100, R3 and R6 each independently represents an alkylene group having 2 to 4 carbon atoms, and Y and Z each independently represent a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, a monovalent phosphoric acid group, salts of ammonia or organic amines, or mono- or diesters of alkyl groups having 1 to 4 carbon atoms), monovalent sulfonic acid groups (monovalent metals,
It includes salts of valent metals, ammonia or organic amines, or esters of alkyl groups having 1 to 4 carbon atoms.

), or a monovalent sulfate group (however, a monovalent sulfate group, divalent gold, ammonia, or an organic amine salt, or a carbon number of 1 to
Contains an ester of 4 alkyl groups. ), or (2) Y and Z together represent two phosphate groups, a divalent sulfonic acid group, or a divalent sulfate group. ), one or two selected from acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and salts thereof (allyl ether monomers shown in Monomers that can be copolymerized with these monomers are copolymerized using a polymerization initiator.

The pressure-sensitive adhesive composition of the present invention obtained in this way is
That-! Although it can be used as a pressure-sensitive adhesive, various additives as shown below can be added as necessary.

First, if it is necessary to further increase the adhesive strength of the pressure-sensitive adhesive composition of the present invention, use a tackifier resin having a softening point of about 60° C. or higher, such as rosin resin, petroleum resin resin, coumaron indense resin, etc. based resin, phenolic resin, etc. can be added in an amount of 60 parts by weight or less, preferably in the range of 5 to 40 parts by weight, per 100 parts by weight of the polymer in the aqueous polymer dispersion (A). If it is necessary to increase the adhesive strength, use a liquid tackifying resin with an average molecular weight of s, o o o ~ 20.
OOO low molecular weight polymers, plasticizers, etc. can be added.

In addition, if it is necessary to further increase the cohesive force of the pressure-sensitive adhesive composition of the present invention, 0.005 to 2 parts by weight based on 100 parts by weight of the polymer in the aqueous polymer dispersion (A). Within this range, epoxy compounds, melamine compounds, isocyanate compounds, etc. that can act as external crosslinking agents can also be added in the form of aqueous solutions, aqueous dispersions, or organic solvent solutions.

The pressure sensitive adhesive composition of the present invention further includes, if necessary,
Known additives such as antifoaming agents, thickeners, viscosity modifiers, colorants, fillers, and anti-aging agents can also be added. Incidentally, some thickeners are polymers having a large number of carboxyl groups and exhibit a thickening effect when alkali is added, but the use of such thickeners does not impair the effects of the present invention. In fact, more favorable results may be obtained.

The pressure-sensitive adhesive composition of the present invention thus obtained has both high cohesive strength and high adhesive strength, and this cohesive strength does not decrease significantly even at relatively high temperatures, and therefore can be used over a wide temperature range. In addition to exhibiting excellent repulsion resistance, it also exhibits good adhesion and repulsion resistance to non-polar substrates such as polyethylene and polypropylene, which are generally difficult to adhere to.Using these properties, it can be applied to a wide range of applications. In particular, it can be effectively used for pressure-sensitive adhesive tapes and sheets.

Although it is not yet clear why the effects obtained by the pressure-sensitive adhesive composition of the present invention are based on, it is clear that the pressure-sensitive adhesive composition of the present invention is dried on a substrate. The adhesive layer obtained is formed by bonding the carboxyl groups in the polymer having a relatively large number of carboxyl groups with the polyvalent metal ions generated from the polyvalent metal compound (B) or the polyvalent metal compound (F3). , produces a three-dimensional network structure that can contribute to the expression of high cohesive force, and the network structure does not contain carboxyl groups, but has a relatively small amount of carboxyl groups, which can contribute to the expression of high adhesive force. This is presumed to be due to the polymer-filled form.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, unless otherwise specified, "part" in the examples means "part by weight" and "%" means % of heavy electric charge.

Reference Example 1 First, an aqueous emulsion of the two types of unsaturated monomers shown below was prepared. Average number of added moles of ethylene oxide 4) 2 = tx, 8 parts of polyoxyethylene adduct of secondary alcohol having 12 to 14 carbon atoms (Nippon Shokubai Chemical Co., Ltd., Softanol 200■) and 80 parts of deionized water are mixed and stirred. 290 parts of an aqueous unsaturated monomer emulsion obtained by

■180 parts of butyl diacrylate, 4 parts of vinyl acetate, 16 parts of acrylic acid, 2 parts of polyoxyethylene nonylphenyl ether sulfate ammonium salt (average number of added moles of ethylene oxide: 4), secondary alcohol with 12 to 14 carbon atoms. 8 parts of polyoxyethylene adduct (manufactured by Nippon Shokubai Chemical Co., Ltd., Softanol 200■) and 8 parts of deionized water
290 parts of an unsaturated monomer aqueous emulsion obtained by mixing and stirring 0 parts.

A glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen gas inlet, and a reflux condenser was charged with 246 parts of deionized water, and the flask was purged with nitrogen. Then, the temperature was raised to 55°C,
After adding 30 parts of the above unsaturated monomer aqueous emulsion (■) and stirring at 55°C for 10 minutes, 10 parts of a 20% aqueous solution of ammonium persulfate and 1 part of a 10% aqueous solution of sodium bisulfite were added. to initiate polymerization.

10 minutes after the start of polymerization, the remaining 260 parts of the unsaturated monomer aqueous emulsion ■ and 4 parts of a 10% aqueous solution of sodium bisulfite were added for 50 minutes while maintaining the reaction temperature at 70°C. The emulsion polymerization was carried out by adding continuously at a uniform rate over the period of time. Then, after continuing to mix and stir at 70°C for 30 minutes, while maintaining the reaction temperature at 70°C, unsaturated monomer aqueous emulsion ■ and, in parallel, 5 parts of a 10% aqueous solution of sodium bisulfate were added over 70 minutes. Emulsion polymerization was allowed to proceed by adding continuously at a uniform rate. Next, mixing and stirring were continued for 60 minutes at 70°C to complete polymerization, and after cooling to room temperature, aqueous ammonia was added, and P H
An aqueous polymer dispersion (1) having a solid content of 7.0% and a solid content of 48.8% was obtained.

Reference Example 2 290 parts of each of the same unsaturated monomer aqueous emulsions (2) and (2) as used in Reference Example 1 were prepared, and each of them was subjected to emulsion polymerization by the method shown below.

A glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen gas inlet, and a reflux condenser was charged with 116 parts of deionized water, and the flask was purged with nitrogen. Then, the temperature was raised to 55°C,
After adding 15 parts of the 290 parts of the above unsaturated monomer aqueous emulsion and stirring at 55°C for 1 minute, 5 parts of a 2°π aqueous solution of ammonium persulfate and 1°π of sodium bisulfate were added. Polymerization was started by adding 0.5 parts of an aqueous solution.

10 minutes after the start of polymerization, while maintaining the reaction temperature at 70°C, 120 parts of the remaining 275 parts of the unsaturated monomer aqueous emulsion and 4.5 parts of a 10% aqueous solution of sodium bisulfite were added in parallel. Emulsion polymerization was allowed to proceed by continuous addition at a uniform rate over a period of minutes. Then, mixing and stirring were continued for 60 minutes at 70°C to complete polymerization.

Aqueous ammonia was added to a mixture of the two obtained aqueous polymer dispersions in equal amounts to obtain an aqueous polymer dispersion (2) having a pH of 7.1 and a solid content of 49.7%.

261 Reference 1 + 113 Composition obtained by combining unsaturated monomer aqueous emulsions ① and ② used in Reference Example 1: 360 parts of butyl acrylate, 20 parts of vinyl acetate, 20 parts of acrylic acid, polyoxyethylene nonylphenyl ether sulfuric acid Ester ammonium salt (average number of added moles of ethylene oxide: 4) 4 parts, carbon number 12-1
EXAMPLE 1 580 parts of an aqueous unsaturated monomer emulsion was prepared from 16 m of the polyoxyethylene adduct of secondary alcohol No. 4 (Softanol 200cm, manufactured by Nippon Shokubai Chemical Industry Co., Ltd.) and 160 parts of deionized water.

246 parts of deionized water was charged into a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen gas inlet, and a reflux condenser, and the flask was purged with nitrogen. Then 5
The temperature was raised to 5°C, and 30% of the above unsaturated monomer aqueous emulsion was
After stirring at 55° C. for 10 minutes, 10 parts of a 20% aqueous solution of ammonium persulfate and 1 part of a 10% aqueous solution of sodium bisulfite were added to initiate polymerization. 10 minutes after the start of polymerization, the reaction temperature was increased to 70°C.
The remaining 550% of the unsaturated monomer aqueous dispersion while maintaining at 'C.
part and parallel to this 10% of sodium bisulfite
Emulsion polymerization was allowed to proceed by continuously adding 9 parts of the aqueous solution at a uniform rate over 120 minutes. Next, mixing and stirring was continued for 60 minutes at 70°C to complete the polymerization, and then cooled to room temperature, and aqueous ammonia was added to adjust the pH to 6.9 and solid content to 4.
A 9.8% aqueous polymer dispersion (3) was obtained.

Reference Example 4 First, three types of unsaturated monomer aqueous emulsions shown below were prepared.

(2) 144 parts of an aqueous unsaturated monomer emulsion obtained by mixing and stirring 60 parts of 2-ethylhexyl diacrylate, 40 parts of ethyl acrylate, 1 part of sodium dodecylbenzenesulfonate, and 43 parts of deionized water.

■144 parts of an unsaturated monomer aqueous emulsion obtained by mixing and stirring 50 parts of 2-ethylhexyl diacrylate, 47 parts of ethyl acrylate, 3 parts of acrylic acid, 1 part of sodium dodecylbenzenesulfonate, and 43 parts of deionized water. .

@144 parts of an unsaturated monomer aqueous emulsion obtained by mixing and stirring 40 parts of 2-ethylhexyl diacrylate, 54 parts of ethyl acrylate, 6 parts of acrylic acid, 1 part of sodium dodecylbenzenesulfonate, and 16 parts of deionized water. .

163 ml of deionized water was added to a glass flask equipped with a stirrer, thermometer, addition funnel, nitrogen gas inlet, and reflux condenser.
5 parts were charged and the mixture was replaced with nitrogen.

Then, the temperature was raised to 55°C, 21.6 parts of the above unsaturated monomer aqueous emulsion (2) was added, and after stirring at 55°C for 10 minutes, 7.5 parts of a 20% aqueous solution of ammonium persulfate was added.
(part and hydrogen sulfite) 10% aqueous solution of IJum 0.
7 parts were added to initiate polymerization.

After 10 minutes from the start of polymerization, the remaining unsaturated monomer aqueous emulsion (1) was heated while maintaining the reaction temperature at 70°C.
4 parts and in parallel 10 parts of sodium bisulfite
Emulsion polymerization was allowed to proceed by continuously adding % aqueous solution #i, s parts at a uniform rate over 50 minutes. Then 70℃
After continuing to mix and stir for 30 minutes at 29°C, while maintaining the reaction temperature at 70°C, unsaturated monomer aqueous emulsion (1) and, in parallel, 2.5 parts of a 10% aqueous solution of sodium hydrogen sulfite were added over 60 minutes. Emulsion polymerization was allowed to proceed by adding continuously at a uniform rate. Then 70
After continuing mixing and stirring at ℃ for 30 minutes, while maintaining the reaction temperature at 70℃, add 2.5 parts of a 10% aqueous solution of IJum to 60 parts of an unsaturated monomer aqueous emulsion @ and hydrogen sulfite in parallel. Emulsion polymerization was allowed to proceed by continuous addition at a uniform rate over a period of minutes. Next, mixing and stirring was continued for 60 minutes at 70°C to complete the polymerization, and after cooling to room temperature, aqueous ammonia was added to obtain a pH of 7.0 and a non-volatile content of 49.8.
% polymer aqueous dispersion (4) was obtained.

Reference Example 5 334 parts of polyethylene glycol monoallyl ether (containing an average of 2 ethylene oxide units per molecule) and 100 parts of water were placed in a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, gas introduction pipe, and reflux condenser. The inside of the reaction vessel was purged with nitrogen while stirring, and heated to 95°C for 30 minutes in a nitrogen atmosphere. Thereafter, an aqueous solution of 139.3 parts of maleic acid and 1442 parts of ammonium persulfate dissolved in 225 parts of water was added over 120 minutes. After addition, 14.2 parts of 20
% ammonium persulfate solution was added over 20 minutes. After the addition was completed, the temperature inside the reaction vessel was maintained at 95° C. for 100 minutes to complete the polymerization reaction, and a block copolymer (1) was obtained.

A 55% aqueous solution of this copolymer (1) had a pH of 1.1 and a viscosity of l 36 cps. The polymerization rate was 97.8%. Moreover, the molecular weight of this copolymer (1) was 1,800, and the acid value was 285. Next, a 40% aqueous sodium hydroxide solution was added to neutralize the mixture to obtain an aqueous sodium salt solution of copolymer (1). This copolymer (1) IJ
The pH of a 45% aqueous solution of Um salt is 8.2 and the viscosity is 203.
It was cps.

Reference Example 6 20 parts (solid content equivalent) of the block copolymer (1) obtained in Reference Example 5 was placed in a stainless steel beaker, and 180 parts of water was added to obtain an aqueous dispersant solution. After adding 300 parts of glass beads (manufactured by Toshiba, 'GB-503M') to this dispersant aqueous solution, Lab Body Spar (manufactured by Tokushu Kika Kogyo Co., Ltd., 'MR') was added.
, -L type 1), 200 parts of activated zinc white (manufactured by Sakai Chemical Industry Co., Ltd., wet method zinc white) was added over 10 minutes. After the addition was completed, stirring was continued for 30 minutes to obtain a zinc oxide aqueous dispersion (1) with a pH of 8.3.

Reference Example 7 Block copolymer (1) used in Reference Example 6 20
Aqueous dispersion of zinc oxide with a pH of 8.4 was carried out in exactly the same manner as in Reference Example 6, except that part (in terms of solid content) was changed to low-molecular sodium polyacrylate (manufactured by Nippon Shokubai Chemical Co., Ltd., Aqualic DL-40). Body (2) was obtained.

Examples 1 to 12, Comparative Examples 3 to 6 Polymer aqueous dispersions (1) to (4) obtained in Reference Examples 1 to 4
) to 100 parts of each of the zinc compounds shown in Table 1 were added to the amount shown in Table 1 and mixed uniformly to prepare a pressure-sensitive adhesive composition.

Comparative Example 1.2.7.8 Polymer aqueous dispersions (1) to (4) obtained in Reference Examples 1 to 4
), a pressure-sensitive adhesive composition was prepared without adding anything else.

The adhesive force, holding force (cohesive force), and repulsion resistance of the pressure-sensitive adhesive compositions obtained in Examples 1 to 12 and Comparative Examples 1 to 8 were measured by the methods shown below.

The results are shown in Table 1.

<Adhesive strength> A pressure-sensitive adhesive composition was applied to one side of a 25μ thick polyester film so that the thickness after drying was 45μ,
Dry at 105℃ for 3 minutes to make a pressure-sensitive adhesive tape, JI
8 180° peeling adhesive strength (g
/25 mm) was measured.

<Holding power> A pressure-sensitive adhesive tape similar to the adhesive strength test was made, JIs Z
-0237, measurements were taken at 40°C and 80°C under a load of 1 kg.

<Repulsion resistance> A pressure-sensitive adhesive composition was applied to a release paper so that the thickness after drying was 60 μm, dried at 105°C for 3 minutes, and then coated with a rayon nonwoven fabric (14.9 parts). m'i)
A double-sided adhesive tape with a tape thickness of 130 μm was made by transferring it to both sides of the paper. Cut this double-sided adhesive tape into a piece with a width of 20711111 and a length of 11 (Lmm), wrap it around a stainless steel vibrator with a 50 vrm limit, and tape a width of 11 mm on the outside.
A stainless steel sheet with a length of 5 mm, a length of 100 mm, and a thickness of 0.15 mw was bonded together, and after 24 hours at 70°C, the state of the stainless steel sheet springing up was observed.

Those with no splashing were considered to be passed.

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Claims (1)

[Scope of Claims] 1. A pressure-sensitive adhesive composition comprising a polymer aqueous dispersion (A) shown in the following item (1) and a polyvalent metal compound (13) as essential components, which The polymer contained in the aqueous polymer dispersion (A) is 50% of the total polymer contained in the pressure adhesive 1 composition.
A pressure-sensitive adhesive composition, characterized in that the polyvalent metal compound (B) accounts for at least 0.1% equivalent of the carboxyl group in the entire polymer, . (lself) (I) The content of unsaturated carboxylic acid (a) in the monomer component system containing the largest amount of unsaturated carboxylic acid (a) is 2 to
50 double twill%, and the content of unsaturated carboxylic acid (a) in the monomer component yarn with the highest content and the monomer component system with the lowest content of unsaturated carboxylic acid (a) The difference in rate is 2
Polymer aqueous dispersion (A) obtained by mixing two or more types of polymer aqueous dispersions obtained by individually emulsion polymerizing each of the monomer component systems having a weight t% or more, or Polymer aqueous dispersion (b) obtained by mixing one or two micrometers of a polymer aqueous dispersion obtained by successive emulsion polymerization of each monomer component, or the polymer aqueous dispersion An aqueous polymer dispersion (...) obtained by mixing (a) and an aqueous seed polymer dispersion (b), in which the monomer composition of all the polymers contained is an unsaturated carboxylic acid ( a) Q2-20 heavy snack%, the number of carbon atoms in the alkyl group is 4
-12 acrylic acid alkyl ester (b) 5
0 to 998 percent unsaturated and other copolymerizable 11
Single pupil (c) 0~4.9.8 double lid% (a),
The sum of (b) and (C) is 100%. ) is a polymer aqueous dispersion (A).