JP3424266B2 - Method for producing aqueous emulsion and pressure-sensitive adhesive - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an aqueous emulsion and a pressure-sensitive adhesive.

[0002]

2. Description of the Related Art It is known that a method for producing an ethylene-vinyl ester- (meth) acrylic acid ester-based copolymer emulsion and that the emulsion is used as a pressure-sensitive adhesive. For example, Japanese Patent Publication No. 60-47315 discloses a monomer (composition ratio) composed of α-olefin-vinyl ester- (meth) acrylic acid ester (5 to 30/20 to 60/25 to 60% by weight). A pressure sensitive adhesive with a multi-component copolymer emulsion having is shown. Further, JP-A-55-142013 discloses that ethylene-
Acrylic ester-vinyl acetate-specific amide-based monomer-olefinically unsaturated monomer (10-30 / 30)
.About.69 / 25 to 55 / 0.5 to 8/0 to 8 wt%), a multi-component copolymer emulsion having a monomer (composition ratio) and a technique of using the emulsion as a pressure-sensitive adhesive are disclosed. . Japanese Patent Publication No. 59-48047 discloses ethylene-vinyl ester- (meth) acrylic acid ester-α, β-unsaturated carboxylic acid di (mono) ester (5-30 / 20-60 / 10-50 / 5-5). 30% by weight) and a technique of using the emulsion as a pressure-sensitive adhesive.

By the way, in carrying out emulsion polymerization, selection of an emulsifier is the most important factor for obtaining a stable emulsion. One of the selection criteria when selecting a nonionic surfactant is HLB (hydrophilic / lipophilic balance). Generally, one guideline is to use a high HLB (high hydrophilicity) for the hydrophilic monomer and a low HLB (high lipophilicity) nonionic surfactant for the hydrophobic monomer.
Chemistry of Polymer Latex (Souichi Muroi, Polymer Society,
The optimum HLB of vinyl acetate, which is a hydrophilic monomer, is 15-18.
5. The optimum HLB of ethylene, which is a lipophilic monomer, is 12
~ 15. Acrylic ester and its polymer II (Eizo Omori, Shokoido, Showa 5)
(Published March 10, 2000, p. 148), emulsion polymerization of acrylic acid ester generally has a polyoxyethylene addition mole number of 30 or more (corresponding to 17 or more in HLB) polyoxyethylene alkyl (or aryl). It is introduced that ethers are often used as nonionic surfactants. Therefore, from the conventional knowledge regarding the optimum HLB of the nonionic surfactant used when producing the ethylene-vinyl acetate-acrylic acid ester-based copolymer emulsion, it is selected from the range of HLB 12 to 18.5. It was common sense for those skilled in the art.

However, in the above known technique, the HL
When the nonionic surfactant of B12 to 18.5 is used, the produced emulsion is not preferable since the grits (aggregates) are produced in an amount of 0.3% by weight or more. Emulsion with a lot of grits adheres to the roll during coating (gum-up phenomenon), and when spraying, it causes problems such as nozzle clogging and poor workability.
When coated on a film, the coated surface (coating thickness after drying 10
.About.30 .mu.), The smoothness of the surface is remarkably impaired, the commercial value is lowered, and the product becomes unusable.

That is, in the prior art, in the polymerization reaction for producing an emulsion, sticky agglomerates (that is, "Glitz") are generated, and the agglomerates are formed on the stirring blade of the polymerization tank or the inner wall of the polymerization tank. Adhesion, thus hindering the smooth progress of the polymerization reaction, and in extreme cases, making it impossible to continue the polymerization reaction by gelation, and filtering the emulsion containing such aggregates with a filter material such as wire mesh or filter cloth. In the case of using the aggregate, the problem that the filter medium is clogged with the aggregate, and when an emulsion containing the aggregate is used as a pressure-sensitive adhesive, when the adhesive is applied, a spot caused by the aggregate is generated on the coated surface. However, there is a problem that the nozzle of the coating spray used is blocked.

[0006]

In view of the present situation, the problem to be solved by the present invention is to provide (normal) adhesive force, adhesive force, cohesive force, curved surface adhesive force, and water resistance of pressure-sensitive adhesive. Provided are a method for producing an aqueous emulsion characterized in that various characteristics such as surface adhesiveness are maintained at sufficiently high levels and the generation of aggregates (grits) during emulsion production is small, and a pressure-sensitive adhesive using the aqueous emulsion. There is a point to do.

[0007]

The present inventors have arrived at the present invention as a result of intensive studies to solve the above problems.

That is, one of the inventions is as follows: (A) 5 to 30% by weight, (B) 20 to 84% by weight,
A method for producing an aqueous emulsion containing a copolymer containing (C) 10 to 74% by weight and (D) 0.1 to 8% by weight, the aqueous method satisfying the following conditions (1) to (4): The present invention relates to a method for producing an emulsion. (1) Use at least (K) nonionic surfactant and (L) anionic surfactant as an emulsion stabilizer during polymerization. (2) The total amount of (K) and (L) used for polymerization is 1.0 to 100 parts by weight of the total amount of (B) and (C) to be provided
10 parts by weight (3) In the range of 0.5 to 6 parts by weight per 100 parts by weight of the total amount of (B) and (C) to be polymerized as at least one kind of (K) nonionic surfactant, HLB6
Use of polyoxyethylene derivative No. 10 to (4) The amount of the (L) anionic surfactant used is 0.5 to 3 parts by weight per 100 parts by weight of the total amount of (B) and (C) to be subjected to polymerization. (A) ethylene (B) α, β-unsaturated carboxylic acid ester represented by the following (formula 1) (C) vinyl ester (D) carboxyl group represented by the following (formula 2), amide group , An N-methylol group,
Copolymerizable olefinically unsaturated monomer having sulfonic acid group, epoxy group or hydroxy group

[0009]

[Chemical 1]

(R ₁ represents hydrogen or a methyl group, R ₂ represents an alkyl group having 1 to 18 carbon atoms, and R _{3 to} R ₅ represent
Each independently represents hydrogen or an alkyl group. However, the total number of carbon atoms of R _{3 to} R ₅ is 18 or less. )

Another aspect of the present invention relates to a pressure-sensitive adhesive containing the above aqueous emulsion as a main component.

The details will be described below. Ethylene is contained in the copolymer of the present invention. The content of ethylene in the copolymer is 5 to 30% by weight. If the content is too small, the (normal) adhesive strength, particularly the adhesive strength to the non-polar polymer adherend and the curved surface adhesive strength, will be poor, while if the content is too large, the adhesive strength and holding power will be poor.

Examples of the (B) α, β-unsaturated carboxylic acid ester represented by the above (formula 1) contained in the copolymer of the present invention include methyl acrylate, ethyl acrylate, propyl acrylate, Butyl acrylate, amyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, Examples thereof include butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, lauryl methacrylate, stearyl methacrylate and the like. In particular, the carbon number of R ₂ in (Formula 1) is 4 to 12
Are preferred. As (B), one type of α, β-unsaturated carboxylic acid ester represented by (Formula 1) may be used alone, or two or more types may be mixed and used. The content of (B) in the copolymer is 20 to 84% by weight, preferably 25 to 70% by weight. If the content is too small, the adhesive strength will be poor, and if the content is too large, the adhesive strength to the non-polar polymer adherend will be poor. In addition,
An α, β-unsaturated carboxylic acid diester can be used in combination for improving the adhesive strength without impairing the original performance as a pressure-sensitive adhesive, and the preferable α, β-unsaturated carboxylic acid diester is Examples thereof include maleic acid diester and fumaric acid diester.

The (C) vinyl ester represented by the above (formula 2) contained in the copolymer of the present invention is, for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl laurate, versatic. Examples thereof include vinyl acetate, and vinyl acetate and a combination of vinyl acetate and higher fatty acid vinyl are preferable. In addition,
As (C), one type of vinyl ester represented by (Formula 2) may be used alone, or two or more types may be mixed and used. The content of (C) in the copolymer is 10 to
It is 74% by weight, preferably 24-69% by weight. If the content is too small (normal), the adhesive strength and holding power are poor,
On the other hand, when the content is too large, the adhesive strength is poor.

The (D) carboxyl group, amide group, N-methylol group, sulfonic acid group, epoxy group or hydroxy group-containing copolymerizable olefinically unsaturated monomer contained in the copolymer of the present invention is For example, a carboxyl group-containing monomer such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid (including half ester), maleic acid (including half ester) and its anhydride; N-methylol acrylamide, N-butoxymethyl acrylamide, etc. N-methylol derivative monomer; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxy group-containing monomer such as mono (meth) acrylate of polyhydric alcohol and monoallyl ether of polyhydric alcohol; dimethylamino Ethyl methacrylate Amino group-containing monomers such as dimethylaminopropylacrylamide; Epoxy group-containing monomers such as glycidyl (meth) acrylate; Amide group-containing monomers such as acrylamide, methacrylamide, and maleamide; Sodium vinyl sulfonate, Sodium methallyl sulfonate, 2 -Sulfonyl group-containing monomers such as sodium acrylamido-2-methylpropane sulfonate and the like can be mentioned. (D) in the copolymer
Content of 0.1 to 8% by weight, preferably 0.3 to 6
% By weight. If the content is too small, the particle stability of the emulsion is poor, while if it is too large, the water-resistant adhesion is poor.

The copolymer of the present invention comprises the above (A) to
In addition to (D), (E) a copolymerizable crosslinkable monomer having two or more polymerizable double bonds may be contained. Examples of the monomer include diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, ethylene glycol diacrylate, allyl methacrylate, adipic acid diacrylate, trimethylolpropane dimethacrylate, and the like. The content of (E) in the copolymer is usually 5% by weight or less, preferably 3% by weight or less. By using (E) in such a range, the crosslinkability of the emulsion can be improved without impairing the original properties of the pressure-sensitive adhesive.

The aqueous emulsion of the present invention has the above (1).
It is manufactured by a method that satisfies the conditions (4) to (4).

In the production method of the present invention, at least the (K) nonionic surfactant and the (L) anionic surfactant are used as the emulsion stabilizer during the polymerization, and the total amount of the (K) and (L) used. Is subjected to polymerization (B) and (C)
It is necessary to use it in the range of 1.0 to 10 parts by weight, preferably 1.5 to 8 parts by weight, per 100 parts by weight of total. If the amount used is too small, coarse particles are generated during the production of the emulsion, whereas if the amount used is too large, the water resistance is poor.

Examples of the nonionic surfactant (K) include polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene / polyoxypropylene block copolymer, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, etc. Can be raised.
Here, in the present invention, HLB6 is used as at least one (K) nonionic surfactant in a range of 0.5 to 6 parts by weight per 100 parts by weight of the total amount of (B) and (C) to be subjected to polymerization. It is particularly important to use polyoxyethylene derivatives of 10 to 10. When the amount used is too small, coarse particles in the emulsion increase, and when it is significant, gelation occurs. Even if an emulsion is obtained, 0.3% by weight or more of grits is generated. On the other hand, if the amount used is too large, the water resistance and holding power are poor. In the present invention, in addition to the above-mentioned nonionic surfactant having HLB, nonionic surfactants of HLB 10 to 20 are usually 5 parts by weight per 100 parts by weight of the total amount of (B) and (C) to be subjected to polymerization. Parts or less can be used together within a range that does not impair the effects of the present invention.

Examples of (L) anionic surfactants include alkyl sulfate ester salts, alkylbenzene sulfonates, alkylsulfosuccinates, alkyl diphenyl ether disulfonates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl phosphates. Ester etc. can be mentioned. The amount of (L) used is
The total amount of (B) and (C) used for the polymerization is 0.5 to 3 parts by weight per 100 parts by weight. If the amount used is too small, the viscosity increases with time in a compounded product to which an inorganic filler, a thickener, etc. are added, while if the amount used is too large, coarse particles in the emulsion increase and Causes gelation. Even if an emulsion is obtained, the pressure-sensitive adhesive made of the emulsion has poor water resistance.

In the present invention, a protective colloid (M) may be used in addition to the above-mentioned (K) nonionic surfactant and (L) anionic surfactant. (M) Examples of protective colloids include polyvinyl alcohols such as partially saponified polyvinyl alcohol, completely saponified polyvinyl alcohol, sulfonic acid modified polyvinyl alcohol, carboxyl modified polyvinyl alcohol, silanol group modified polyvinyl alcohol; hydroxyethyl cellulose, methyl cellulose, carboxy. A cellulose derivative such as methyl cellulose can be used.
The amount of (M) used is usually 3 parts by weight or less, preferably 0.1 to 3 parts by weight, per 100 parts by weight of the total amount of (B) and (C) used for the polymerization. If the amount used is too small, the particle stabilizing effect may be insufficient, while if the amount used is too large, an abnormal thickening phenomenon may occur during polymerization.

Specific examples of the method for producing the aqueous emulsion of the present invention are as follows. That is, (B)
To (D); if necessary (E); (K) and (L); if necessary (M); radical polymerization initiator, pH adjuster,
An emulsion dispersion is obtained by stirring and mixing a polymerization chain transfer agent and the like in water. Next, using the emulsified dispersion,
Emulsion polymerization is carried out under ethylene pressure of 0 kg / cm ² . The polymerization system may be either batch system or continuous system.
The polymerization reaction temperature is usually in the range of 30 to 70 ° C. The radical polymerization initiator is a water-soluble radical initiator used in ordinary emulsion polymerization, for example, hydrogen peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, tert-butyl hydroperoxide, etc. alone or L- , D-ascorbic acid, sulfite, rongalit, ferrous sulfate in combination with a reducing agent such as a redox system. As the pH adjuster, acids such as hydrochloric acid, phosphoric acid, acetic acid, succinic acid, carbonic acid and salts thereof; bases such as alkali metal hydroxide, aqueous ammonia and amine are used. A mercaptan or the like can be used as the chain transfer agent.

The pressure-sensitive adhesive of the present invention contains the aqueous emulsion of the present invention as a main component, and the content thereof is usually 30 to 70% by weight (based on solid content), preferably 45 to 70% by weight. Is. At the stage of using the aqueous emulsion as a pressure-sensitive adhesive, an antifoaming agent, a viscosity modifier, a filler, etc. may be added as long as the original characteristics are not impaired.

The pressure-sensitive adhesive of the present invention can be widely applied to adhesive tapes, adhesive sheets, adhesive labels and the like. These products are those that have good pressure-sensitive adhesive properties balanced by applying the emulsion of the present invention to substrate materials such as plastic films, papers, metal foils, etc. using conventional and known equipment and methods. can get. Particularly, it has excellent adhesive force, adhesive force and holding power even for non-polar adherends such as polyolefin. Further, since it has excellent holding power, there is no drawback that the adhesive will come out when it is stored for a long period of time.

[0025]

EXAMPLES Next, the present invention will be described with reference to examples.
It is not limited to this. Example 1 Ion exchange in pressure resistant autoclave equipped with anchor type stirrer
1300 parts by weight of water, emulsion stabilizer shown in Table 1, 1 layer of acetic acid
Parts, sodium acetate 5 parts by weight, Rongalit 10 parts by weight
Part of an aqueous solution, and under stirring, nitrogen, then ethyl
Replaced by Next, the temperature in the system is raised to 50 ° C.,
544 parts by weight of vinyl acetate, 2-ethylhexyl acrylate
Sil 544 parts by weight, acrylic acid 13.6 parts by weight and meta
Mixed monohydrate consisting of 8.16 parts by weight of sodium rilsulfonate
Solution and 6.25% by weight aqueous ammonium persulfate solution
450 parts by weight of liquid is uniformly charged simultaneously for 4 hours.
I see. During this time, the reaction temperature was adjusted to 50 ° C. to keep the temperature constant during the polymerization.
Ethylene pressure is 60 kg / cm²Kept at. Then further
Aging was carried out at 50 ° C. for 1 hour. Aqueous thus obtained
The emulsion was 45% by weight solids. The emul
John on a release paper with a thickness of 110μ and an adhesive coating thickness of 2
Using an automatic coating device so that it becomes 5 microns (after drying)
Apply evenly and dry with warm air at 80 ° C for 5 minutes.
55 g / m ²Transfer to high quality paper for adhesive sheet of
I got a dressing sheet. Regarding the obtained pressure-sensitive adhesive sheet,
Evaluation was performed by the method described above. The results are shown in Table 2.

(1) Adhesive Strength (Normal Adhesive Strength) A stainless steel plate (SUS304), a polyethylene (PE) plate and a polypropylene (PPr) plate that are well polished with a water resistant abrasive paper No. 280 according to JIS R-6253 are applied to JIS.
The sample crimped by an automatic crimping device according to the method of Z-238 is subjected to 180 ° C. under the conditions of 23 ° C. and 65% RH (relative humidity).
The strength (unit: g / 25 mm) at the time of peeling at a rate of 300 mm / min in the direction of the angle was measured by a Tensilon tensile tester and used as the (normal state) adhesive force to each adherend. (2) Adhesive strength (tack test) DOW method (Proc. Inst. Rubber I
nd. 1105 (1954)), 23 ° C, 65%
Under the condition of RH, a 10 cm long adhesive sheet was attached to the slope on a stainless plate with an inclination angle of 30 degrees, and the upper part of the slope 10
From the position of cm, 32 kinds of stainless steel balls with a diameter of 1/32 inch to 1 inch are rolled at an initial speed of 0 and the size of the ball with the maximum diameter (ball No.) that stops on the adhesive sheet. is there. No. The larger the value, the better the adhesive strength.

(3) Cohesive force (holding force) A test piece was attached to a stainless steel plate (SUS 304), which was well polished with a water-resistant abrasive paper of No. 280 according to JIS R-6253, so that the adhesive area of the test piece was 25 × 25 mm. 2k
The sample was pressed back and forth once with a rubber roller of g, and the pressed sample was subjected to a static load of 1 kg in an atmosphere of 40 ° C., and the time when the load dropped was shown. The longer the time, the better the cohesive strength. (4) Curved surface adhesive strength and water resistant curved surface adhesive strength
A 1.0 cm × 2.5 cm test piece was attached, and the curved surface adhesive strength was left under the conditions of 105 ° C. × 8 Hr and 0 ° C. × 16 Hr, and this was performed for 2 cycles, and then evaluated according to the following criteria. The water resistant curved surface adhesion was evaluated by observing the degree of adhesion of the test piece after immersing the round bar in water at 25 ° C. and observing the adhesion for 24 hours, and then evaluating the same criteria. When there is no abnormal appearance ○ When the tip is floating △ When it is completely peeled off ×

(5) When the grits emulsion is filtered through a 300-mesh wire net and the grits recovered on the wire net is less than 0.3% by weight of the emulsion, it is evaluated as ◯, and when it is 0.3% by weight or more. Was evaluated as x.

Examples 2 to 7 and Comparative Examples 1 to 6 The procedure of Example 1 was repeated except that the conditions shown in Tables 1 and 3 were used. The results are shown in Tables 2 and 4.

The results show the following. In all the examples satisfying the conditions of the present invention, the results to be satisfied are shown in all the evaluation items. On the other hand, each comparative example lacking the definition of the present invention shows unsatisfactory results as follows. In Comparative Examples 1 to 3 in which the polyoxyethylene derivative of HLB 6 to 10 was used in an excessively small amount, aggregates were generated and gelation occurred, and even if an emulsion was obtained, a pressure-sensitive adhesive composed of the emulsion Has 0.3% by weight or more of grits. In Comparative Example 4 in which the amount of all emulsifiers is excessive, even if an emulsion is obtained, the pressure-sensitive adhesive made of the emulsion is inferior in water-resistant curved surface adhesive strength. In Comparative Example 5 in which the amount of the anionic surfactant used was excessive, tacky aggregates were generated and gelation occurred.
Comparative Example 6 containing too little ethylene is inferior in normal state adhesive strength, curved surface adhesive strength and water resistant curved surface adhesive strength.

[0031]

[Table 1] −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−                             Example                      1 2 3 4 5 6 7 Emulsion stabilizer * 1   K: Nonionic surfactant     K1 (HLB = 7.8) 0.7 2.0 0.7 0 0.7 0 5.0     K2 (HLB = 9.2) 0 0 0 3.0 0 0.7 0     K3 (HLB = 10.2) 0 0 0 0 0 0 0     K4 (HLB = 17.1) 0.7 2.0 0.7 0 0.7 0.7 0     K5 (HLB = 13.3) 0.7 0 0.7 3.0 0.7 0.7 0     K6 (HLB = 3.7) 0 0 0 0 0 0 0   L: Anionic surfactant     L1 0.6 0.8 0.6 0.6 0.6 0.6 0     L2 0 0 0 0 0 0 1.4  (K + L total) 2.7 4.8 2.7 6.6 2.7 2.7 6.4   M: Protective colloid     M1 0.5 0 0.5 0.5 0.5 0.5 0 Structure of copolymer * 2     A 18.4 9.2 18.4 10.4 14.4 18.4 18.0     B 40 62 40 40 24 40 40     C 40 26 40 48 60 40 40     D1 1 2 1 1 1 1 1     D2 0.6 0.8 0.6 0.6 0.6 0.6 1.0 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0032]

[Table 2] ------------------------------------------ Example 1 2 3 4 5 6 7 Evaluation Pressure-sensitive adhesiveness Adhesive force g / 25mm PE 780 1100 850 850 860 820 1030 PPr 900 1230 870 1330 850 860 1100 SUS 1010 1400 890 1870 910 970 1400 Adhesive force No 12 17 11 12 10 12 16 Cohesive force component 580 620 820 860 860 1100 560 740 Curved surface adhesion ○ △ ○ △ ○ ○ △ Water resistant curved surface adhesion ○ △ ○ ○ ○ ○ △ Gritz concentration 10 ^-4 wt% 32 154 324 138 89 54 289 Properties ○ ○ ○ ○ ○ ○ ○ − − − − −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0033]

[Table 3] −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−                         Comparative example                      1 2 3 4 5 6 Emulsion stabilizer * 1   K: Nonionic surfactant     K1 (HLB = 7.8) 0 0 0 3.0 0.7 3.0     K2 (HLB = 9.2) 0 0 0 0 0 0     K3 (HLB = 10.2) 0 0 0.7 0 0 0     K4 (HLB = 17.1) 0.7 0.7 0.7 3.0 0.7 0     K5 (HLB = 13.3) 0.7 0.6 0.7 3.0 0.7 0     K6 (HLB = 3.7) 0 0.7 0 0 0 0   L: Anionic surfactant     L1 0.5 0.6 0.6 2.0 5.0 0     L2 0 0 0 0 0 1.0  (K + L total) 1.9 2.6 2.7 11.0 7.1 4.0   M: Protective colloid     M1 0.5 0.5 0.5 1.5 0.5 0 Structure of copolymer * 2     A 18.4 18.4 18.4 18.2 18.5 0     B 40 40 40 39 39 82     C 40 40 40 40 39 15     D1 1 1 1 1 1 2     D2 0.6 0.6 0.6 1.8 2.5 1 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0034]

[Table 4] ----------------------------------- Comparative Example 1 2 3 4 5 6 Evaluation Pressure Sensitive Adhesion Adhesion Force g / 25mm PE Gege 720 800 Ge 320 PPr 810 860 860 350 SUS Lulu 890 940 Lu 480 Adhesive force No 10 11 18 Cohesive force diversification 420 560 ＞ 1440 Curved surface adhesion ○ ○ × Water resistant curved surface adhesion △ × × Grits concentration 10 ⁻⁴ wt% 5400 Properties × ○ ○ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

* 1 The numbers in the table of emulsion stabilizers are the total amount of (B) α, β-unsaturated carboxylic acid ester and (C) vinyl ester used for the polymerization of 10
It is the amount used (parts by weight) per 0 parts by weight. The meaning of each symbol is as follows. K1: Noonion surfactant manufactured by Kao Corporation "Emulgen 90"
3 ", polyoxyethylene nonyl phenyl ether, H
LB = 7.8 K2: Noonion surfactant manufactured by Kao Corporation "Emulgen 90"
5 ", polyoxyethylene nonyl phenyl ether, H
LB = 9.2 K3: Noonion surfactant "Pluronic L-64" manufactured by Asahi Denka Co., Ltd., polyoxyethylene-polyoxypropylene block copolymer, HLB = 10.2 K4: Noonion surfactant "Emulgen 93" manufactured by Kao.
1 ", polyoxyethylene nonyl phenyl ether, H
LB = 17.1 K5: Kaonsha noonion surfactant "Emulgen 95"
4 ", polyoxyethylene nonyl phenyl ether, H
LB = 13.3 K6: Kaonsha noonion surfactant “Reodol AO
-15 ", sorbitan sesquioleate, HLB = 3.7.

L1: anionic surfactant "Neoperex F65" manufactured by Kao, sodium dodecylbenzenesulfonate L2: anionic surfactant "Emar 2F needle" manufactured by Kao, sodium lauryl sulfate M1: protective colloid "HEC" manufactured by Fuji Chemical -SG-
15G ", hydroxyethyl cellulose

* 2 The numbers in the copolymer table are% by weight in the copolymer. The meaning of each symbol is as follows. A: ethylene B: 2-ethylhexyl acrylate; however, in Example 3, C-vinyl acetate using -n-butyl acrylate; however, in Example 4, vinyl acetate (40 wt% in the copolymer) And vinyl 2-ethylhexanoate (8 wt% in the copolymer) were used, and in Example 5, vinyl acetate (40 wt% in the copolymer) and Veova-10 (20 wt% in the copolymer) were used. ₁ : Acrylic acid was used. However, in Example 2, D ₂ using 1% by weight of N-methylol acrylamide: sodium methallyl sulfonate

[0038]

As described above, according to the present invention, various properties such as (normal) adhesive strength, adhesive strength, cohesive strength, curved surface adhesive strength, and water resistant curved surface adhesive strength required for pressure-sensitive adhesives are sufficiently high. It has been possible to provide a method for producing an aqueous emulsion having a characteristic that the level is maintained and generation of aggregates (grits) is small at the time of producing the emulsion, and a pressure-sensitive adhesive using the aqueous emulsion.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shizuo Naruzawa 5-1 Anezaki Kaigan, Ichihara City, Chiba Sumitomo Chemical Co., Ltd. (56) Reference JP-A-2-80482 (JP, A) JP-A-56- 45912 (JP, A) JP-A-51-126288 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 2/00-2/60 C08F 220 / 18,218 / 02 C09J 133 / 06

Claims (2)

(57) [Claims] 1. The following (A) 5 to 30% by weight, (B) 20
.About.84% by weight, (C) 10 to 74% by weight and (D) 0.
A method for producing an aqueous emulsion containing a copolymer containing 1 to 8% by weight, wherein the method satisfies the following conditions (1) to (4). (1) Use at least (K) nonionic surfactant and (L) anionic surfactant as an emulsion stabilizer during polymerization. (2) The total amount of (K) and (L) used for polymerization is 1.0 to 100 parts by weight of the total amount of (B) and (C) to be provided
10 parts by weight (3) In the range of 0.5 to 6 parts by weight per 100 parts by weight of the total amount of (B) and (C) to be subjected to polymerization as at least one kind of (K) nonionic surfactant, HLB6
Use of polyoxyethylene derivative No. 10 to (4) The amount of the (L) anionic surfactant used is 0.5 to 3 parts by weight per 100 parts by weight of the total amount of (B) and (C) to be subjected to polymerization. (A) ethylene (B) α, β-unsaturated carboxylic acid ester represented by the following (formula 1) (C) vinyl ester (D) carboxyl group represented by the following (formula 2), amide group , An N-methylol group,
Copolymerizable olefinically unsaturated monomer having sulfonic acid group, epoxy group or hydroxy group (R ₁ represents hydrogen or a methyl group, R ₂ has 1 to 1 carbon atoms.
8 represents an alkyl group, and R _{3 to} R ₅ each independently represent hydrogen or an alkyl group. However, R _{3 to} R ₅
Has a total carbon number of 18 or less. ) 2. A pressure-sensitive adhesive containing the aqueous emulsion according to claim 1 as a main component.