JPH093107A - Pressure-sensitive acrylic emulsion adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pressure-sensitive acrylic emulsion adhesive having improved pressure-sensitive adhesiveness, water resistance and applicability by mixing a specified acrylic copolymer with a tackifying resin. SOLUTION: This pressure-sensitive acrylic emulsion adhesive is obtained by mixing a polymer obtained by adding dropwise a mixture (a) comprising 90-98wt.% at least one (meth)acrylic ester of formula I (wherein R1 is H or CH3 ; R2 is a 4-14C alkyl) and 10-2wt.% at least one monomer selected from among carboxylic monomers, amido monomers and hydroxy monomers to 5-100 pts.wt. tackifying resin (b) emulsified with at least one member selected from among the emulsifiers of the formulas II to V (wherein R1 and R2 are each a 6-18C alkyl, alkenyl or aralkyl; (m) is 8-40; (n) is 8-40; A is a 2-4C alkylene or a substituted alkylene; and M is an alkali metal ion, and amonium ion or an alkanol ion) while polymerizing them with a polymer obtained by emulsion- polymerizing the mixture (a), and optionally mixing the obtained mixture with a chain transfer agent, a crosslinking agent, a pH modifier, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an acrylic emulsion type pressure-sensitive adhesive.

[0002]

2. Description of the Related Art In recent years, acrylic pressure-sensitive adhesives have been widely used in place of natural rubber-based and synthetic rubber-based pressure-sensitive adhesives because of their excellent physical property balance and durability. Among them, solvent-free acrylic pressure-sensitive adhesives, especially emulsion-type acrylic pressure-sensitive adhesives, have come into wide use in order to deal with pollution problems and environmental problems. However, in the case of emulsion-based adhesives, compared with solvent-based adhesives, the emulsifier, which is indispensable for polymerization and dispersion of the adhesive in water, remains in the adhesive film, resulting in lower adhesive properties and lower water resistance and moisture resistance. Is a problem.

It has long been known that the addition of a tackifying resin such as a hydrocarbon type, a terpene type and a rosin type to an acrylic adhesive improves the adhesive properties, particularly the adhesiveness to an olefin adherend. There is. Also in the acrylic emulsion type pressure-sensitive adhesive, it is possible to improve the pressure-sensitive adhesive properties by adding such a tackifying resin.

A method of mixing an emulsion-type tackifying resin with an acrylic emulsion-type pressure-sensitive adhesive is disclosed in JP-A-63-2.
Although disclosed in Japanese Patent No. 56672, in this case, mechanical stability (coating stability) is extremely deteriorated. Further, since a large amount of emulsifier is used in this tackifying resin emulsion, water resistance also deteriorates.

Further, a method in which a tackifying resin is dissolved in a crosslinkable monomer and polymerization is carried out is disclosed in JP-A-58-185.
Although it is disclosed in Japanese Patent No. 668, since a large amount of emulsifier is also used, the water resistance and moisture resistance are poor. Furthermore, when a large amount of tackifying resin is added, the polymerization stability deteriorates.

[0006]

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an acrylic emulsion type pressure-sensitive adhesive containing a tackifying resin having high pressure-sensitive adhesive property, high water resistance and high coating property. To do.

[0007]

According to the present invention as set forth in claim 1, the acrylic emulsion type adhesive has (i) a general formula CH2 = CR1 -COOR2 (wherein R1 represents hydrogen or a methyl group). R2 represents an alkyl group having 4 to 14 carbon atoms) 90 to 98% by weight of at least one (meth) acrylic acid ester, and a carboxyl group-containing monomer, an amide group-containing monomer and a hydroxyl group-containing monomer 100 parts by weight of an acrylic copolymer having 10 to 2% by weight of at least one monomer selected from the group consisting of: and (ii) tackifying resin 5-1
100 parts by weight of the (meth) acrylic acid ester and a monomer mixture of at least one selected from the group consisting of a carboxyl group-containing monomer, an amide group-containing monomer and a hydroxyl group-containing monomer, and emulsified with an emulsifier. At least selected from the group consisting of a polymer (A) obtained by dropwise polymerization in the tackifying resin emulsion, the (meth) acrylic acid ester, and a carboxyl group-containing monomer, an amide group-containing monomer and a hydroxyl group-containing monomer. The gist of the present invention is to provide an acrylic emulsion-type pressure-sensitive adhesive characterized by being obtained by mixing a polymer (B) obtained by emulsion polymerization of a monomer mixture consisting of one kind.

The present invention according to claim 2 provides (i) a general formula C
H2 = CR1 -COOR2 (wherein R1 represents hydrogen or a methyl group. R2 represents an alkyl group having 4 to 14 carbon atoms) and at least one (meth) acrylic acid ester 90 to 98 parts by weight and 100 parts by weight of an acrylic copolymer containing 10 to 2% by weight of at least one monomer selected from the group consisting of a carboxyl group-containing monomer, an amide group-containing monomer and a hydroxyl group-containing monomer as an essential component, And (ii) tackifying resin 5-10
An acrylic emulsion pressure-sensitive adhesive consisting of 0 parts by weight, comprising at least one selected from the group consisting of the (meth) acrylic acid ester and a carboxyl group-containing monomer, an amide group-containing monomer and a hydroxyl group-containing monomer. Polymer (A) obtained by dropwise polymerization of the monomer mixture into a tackifying resin emulsion emulsified with an emulsifier, the (meth) acrylic acid ester, and
A polymer obtained by emulsion-polymerizing a monomer mixture comprising at least one selected from the group consisting of a carboxyl group-containing monomer, an amide group-containing monomer and a hydroxyl group-containing monomer in a state in which a tackifying resin is dissolved in the monomer mixture ( The gist thereof is an acrylic emulsion type pressure-sensitive adhesive characterized by being obtained by mixing with B).

In the present invention according to claim 3, the emulsifier is at least one selected from the group consisting of the following chemical formulas [1], [2], [3] and [4]. The acrylic emulsion type adhesive described in 2 is the gist of the present invention.

[0010]

Embedded image

The (meth) acrylic acid ester having an alkyl group having 4 to 14 carbon atoms used in the present invention is not particularly limited, and examples thereof include n-butyl acrylate and 2-
Examples thereof include ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, and lauryl acrylate. The amount of the (meth) acrylic acid ester added is 90 to 98% by weight. If it is less than 90% by weight, the adhesive strength of the pressure-sensitive adhesive will decrease, and if it exceeds 98% by weight,
Since the cohesive force of the pressure-sensitive adhesive decreases, it is limited to the above range.

The carboxyl group-containing monomer is not particularly limited, and examples thereof include (meth) acrylic acid, maleic acid and itaconic acid.

The amide group-containing monomer is not particularly limited, and examples thereof include (meth) acrylamide, N-isopropylacrylamide, N-vinylpyrrolidone and N-.
Examples thereof include vinyl caprolactam.

The hydroxyl group-containing monomer is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl acrylate.

The amount of at least one monomer selected from the above-mentioned carboxyl group-containing monomer, amide group-containing monomer and hydroxyl group-containing monomer is 2 to 10% by weight. If the addition amount is less than 2% by weight, the cohesive force of the pressure-sensitive adhesive will be low, and if it exceeds 10% by weight, the cohesive force of the pressure-sensitive adhesive will be high and the pressure-sensitive adhesive force will be decreased, so the content is limited to the above range.

In the present invention, a copolymerizable monomer may be added if necessary. The copolymerizable monomer is not particularly limited, and examples thereof include styrene, vinyl acetate, methyl (meth) acrylate, ethyl (meth) acrylate and the like. Addition amount is 25
% By weight or less is preferred.

The tackifying resin used in the present invention is not particularly limited, and examples thereof include gum rosin, tall oil rosin, wood rosin, polymerized rosin, hydrogenated rosin, disproportionated rosin, rosin ester and hydrogenated rosin ester. Rosin resins such as disproportionated rosin ester, polymerized rosin ester, and rosin-modified phenol resin; terpene resin; phenol resin; terpene phenol resin; xylene resin; ketone resin; aliphatic petroleum resin; aromatic petroleum resin; alicyclic Group petroleum resins; coumarone resins; styrene resins and the like.

Examples of the tackifying resin include super ester A-100 (manufactured by Arakawa Chemical Co., Inc., disproportionated rosin ester, softening point 100 ° C.), super ester S-1.
00 (manufactured by Arakawa Chemical Co., disproportionated rosin ester, softening point 1
00 ° C.), Pencel D-160 (manufactured by Arakawa Chemical Co., Ltd., polymerized rosin ester, softening point 160 ° C.), and other commercial products are available.

The tackifying resin used in the polymerization of the component (A) of the present invention is emulsified with an emulsifier.
The emulsifier is not particularly limited, and examples thereof include anionic emulsifiers such as dodecylbenzene sulfonates, alkyl sulfates, and polyoxyethylene alkyl ether sulfonates; nonionics such as polyoxyethylene alkylphenyl ethers and polyoxyethylene alkyl ethers. Examples thereof include system emulsifiers. Considering water resistance, an emulsifier having a copolymerizable double bond is preferable, and the emulsifiers represented by the following formulas [1] to [4] are preferably used. These emulsifiers may be used alone or in combination of two or more.

[0020]

Embedded image

In the formula, R1 and R2 each represent an alkyl group having 6 to 18 carbon atoms, an alkenyl group or an aralkyl group.
m represents an integer of 8 to 40 and n represents an integer of 8 to 40. A represents an alkylene group having 2 to 4 carbon atoms or a substituted alkylene group. M represents an alkali metal ion, an ammonium ion, or an alkanolamine ion.

The amount of the emulsifier added is such that the tackifying resin 10
0.3 to 5 parts by weight is preferable with respect to 0 parts by weight. 0.
When the amount is less than 3 parts by weight, the stability of the tackifying resin emulsion is lowered and the polymerization stability is also lowered, and when the amount is more than 5 parts by weight, the water resistance of the film after coating and drying is lowered. More preferably, it is 0.5 to 3 parts by weight.

In the present invention, the monomer mixture can also be emulsified using the above emulsifier. The amount of the emulsifier added is
0.1 to 3 parts by weight is preferable with respect to 100 parts by weight of the monomer mixture. If it is less than 0.1 part by weight, the monomer mixture is difficult to disperse, and if it exceeds 3 parts by weight, the water resistance as an adhesive is lowered. As an emulsifying method, a commonly used polymerization method such as batch type or continuous type can be used.

The tackifying resin used in the polymerization of the component (B) of the present invention according to claim 2 is used by being dissolved in advance in the monomer mixture constituting the component (B) prior to the polymerization. The addition amount of the tackifying resin is preferably about 1 to 40 parts by weight based on 100 parts by weight of the monomer mixture constituting the component (B). If the amount added is less than 1 part by weight, the adhesive property is not significantly improved by the addition, and if the amount added exceeds 40 parts by weight, the polymerization stability is impaired.

In the present invention, a polymerization initiator is used when the monomer is polymerized. As the polymerization initiator,
Examples thereof include persulfates such as potassium persulfate and ammonium persulfate; water-soluble azo compounds such as azobiscyanovalerianic acid; and redox initiators that use a reducing agent in combination with hydrogen peroxide and the like. When using a water-soluble azo compound, caution is required because the cyano group may remain.
The addition amount is 0.01 to 100 parts by weight of all the monomers.
1.0 parts by weight is preferred. More preferably, 0.03-
0.5 parts by weight.

In the present invention, the acrylic emulsion pressure-sensitive adhesive may be adjusted in molecular weight by using a chain transfer agent such as dodecyl mercaptan, or may be polyfunctional (meth).
An acrylate or the like may be copolymerized. Further, a viscosity modifier such as polyacrylic acid salt or water-soluble urethane resin, a preservative, etc. may be added.

In the present invention, a cross-linking agent may be added to the obtained acrylic emulsion type pressure-sensitive adhesive to cross-link it.
As the cross-linking agent, for example, compounds of aziridine type, blocked isocyanate type, carbodiimide type and the like are used.

In the present invention, the obtained acrylic emulsion type pressure-sensitive adhesive can be adjusted to pH 6 to 9 by using a pH adjuster, if necessary, to improve the mechanical stability. Emulsion to which the pH adjuster is not added,
Mechanical stability is poor and agglomerates are generated during coating, which easily causes coating defects such as streaks and unevenness.

[0029]

The function of the present invention is not always clear,
Since emulsion polymerization is carried out using the emulsion-type tackifying resin as a seed, the acrylic polymer covers the tackifying resin, and it is considered that the mechanical stability does not deteriorate even when mixed with another acrylic emulsion. Further, since most of the acrylic polymer is mixed after the polymerization is completed, the polymerization can be carried out without being affected by the inhibition of the polymerization of the tackifying resin, so that the molecule can be controlled and the adhesive physical properties are improved. Furthermore, when a reactive emulsifier is used as the emulsifier, water resistance can be improved without lowering the adhesive property due to bleed-out of the emulsifier after the pressure-sensitive adhesive tape is prepared, unlike the conventional non-reactive emulsifier. As a result, it is possible to eliminate the use of solvents in fields requiring high adhesive properties and high water resistance, which cannot be replaced by conventional acrylic emulsion adhesives. Further, since it has a high coating property, the coating speed at the time of forming into a tape can be increased, so that the productivity can be increased.

[0030]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Preparation of emulsion-type tackifying resin) 100 parts by weight of Super Ester S-100 (manufactured by Arakawa Chemical Co., Inc., disproportionated rosin ester, softening point: 100 ° C.) was dissolved in 100 parts by weight of ethyl acetate to prepare Aqualon HS- Emulsified and dispersed in 80 parts by weight of ion-exchanged water in which 1.5 parts by weight of 10 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., propoxy group-added polyoxyethylene nonylphenyl ether ammonium salt, EO addition mole number 10) were dissolved. According to a conventional method, the product was dried under reduced pressure with an aspirator to remove ethyl acetate to obtain an emulsion type tackifying resin having a solid content of 50%.

Example 1 In a 1 liter reactor equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube,
200 parts by weight of an emulsion of super ester S-100 (prepared by the above method) in which 0.1 part by weight of ammonium persulfate was dissolved and 100 parts by weight of ion-exchanged water were added, and the mixture was heated to 70 ° C. in a nitrogen atmosphere. As a monomer composition, 56 parts by weight of n-butyl acrylate, 40 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of acrylic acid, and 2 parts by weight of methacrylic acid were charged in a dropping funnel, while maintaining the inside of the reactor at 70 ° C. The mixture was added dropwise over 3 hours to carry out polymerization. After completion of dropping the mixed monomer,
After keeping at 0 ° C. for 1 hour and adding 0.1 part by weight of ammonium persulfate, the temperature was further raised to 90 ° C. and the reaction was carried out for 2 hours. Then, after cooling this polymerization liquid to 30 ° C. or lower, 2
The mixture was neutralized with a 5% aqueous ammonia solution to obtain an acrylic emulsion type polymer containing a tackifying resin. Solid content is 5
At 0%, the ratio of acrylic polymer to tackifying resin was 1: 1. This tackifying resin-containing acrylic emulsion type polymer was designated as A liquid.

Next, 60 parts by weight of ion-exchanged water in which 0.1 part by weight of ammonium persulfate was dissolved was charged into a 1 liter reactor equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube. It was heated to 70 ° C. under a nitrogen atmosphere. As a monomer composition, 56 parts by weight of n-butyl acrylate,
40 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of acrylic acid, 2 parts by weight of methacrylic acid, and 0.05 part by weight of n-dodecyl mercaptan were added to AQUARON HS-10 (Daiichi Kogyo Seiyaku Co., Ltd., propenyl group addition). Polyoxyethylene nonylphenyl ether ammonium salt, EO addition mole number 10) 1.0 part by weight, AQUARON RN-20 (manufactured by Daiichi Kogyo Seiyaku Co., propenyl group addition polyoxyethylene nonylphenyl ether, EO addition mole number 20) 0 0.5 parts by weight and 40 parts by weight of ion-exchanged water were added, mixed and stirred to emulsify, the emulsified monomer was charged in a dropping funnel, and the mixture was added dropwise over 3 hours while maintaining the inside of the reactor at 70 ° C. to carry out polymerization. After the dropping of mixed monomer, 70 ℃
The temperature was maintained for 1 hour, the temperature was further raised to 90 ° C., and the reaction was performed for 2 hours. Then, after cooling this polymerization liquid to 30 ° C. or lower, 2
It was neutralized with a 5% aqueous ammonia solution to obtain an acrylic emulsion type polymer. The solid content was 50%. This acrylic emulsion polymer was used as liquid B.

The liquids A and B obtained as described above (acrylic polymer: tackifying resin) = (100: 1
0) and mixed with Chemitite DZ-22E (Nippon Shokubai Co., Ltd., aziridine crosslinking agent) in a solid content of 0.15.
Parts by weight were added, and the mixture was applied onto a PET film (thickness of 38 μm) and dried to prepare an adhesive tape having an adhesive layer thickness of 25 μm.

(Example 2) (acrylic polymer: tackifying resin) = (100: 20), chemitite DZ-22
An adhesive tape was produced in the same manner as in Example 1 except that E was 0.2 part by weight.

(Example 3) (acrylic polymer: tackifying resin) = (100: 30), chemitite DZ-22
An adhesive tape was produced in the same manner as in Example 1 except that E was 0.3 part by weight.

Example 4 The tackifying resin was (super ester S-100: Pencel D-160 (Arakawa Chemical Co., Ltd., polymerized rosin ester, softening point 160 ° C.)) = (10
0: 150), (acrylic polymer: tackifying resin mixture) = (100: 25), chemitite DZ-2
An adhesive tape was produced in the same manner as in Example 1 except that 0.25 part by weight of 2E was used.

(Example 5) In a 1 liter reactor equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube,
60 parts by weight of ion-exchanged water in which 0.1 part by weight of ammonium persulfate was dissolved was added, and the mixture was heated to 70 ° C. under a nitrogen atmosphere. As the monomer composition, n-butyl acrylate 56
Parts by weight, 40 parts by weight of 2-ethylhexyl acrylate,
5 parts by weight of Pencel D160 (manufactured by Arakawa Chemical Co., Ltd., polymerized rosin ester; softening point 160 ° C.) was dissolved in a mixed monomer of 2 parts by weight of acrylic acid, 2 parts by weight of methacrylic acid, and 0.05 part by weight of n-dodecyl mercaptan. , Aqualon HS-10 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., propenyl group-added polyoxyethylene nonylphenyl ether sulfate ammonium salt, EO-added mole number 10) 1.0 part by weight, Aqualon RN-20 (Dai-ichi Kogyo Seiyaku Co., propenyl Group-added polyoxyethylene nonylphenyl ether, EO addition mole number 20) 0.5 parts by weight, ion-exchanged water 40 parts by weight were added, mixed and stirred to emulsify, and the emulsified monomer was charged into a dropping funnel and the inside of the reactor was adjusted to 70 Polymerization was carried out by dropping over 3 hours while maintaining the temperature at ℃. After the dropping of the mixed monomer, the mixture was kept at 70 ° C. for 1 hour, further heated to 90 ° C., and reacted for 2 hours. Then, after cooling this polymerization liquid to 30 ° C. or lower, 2
It was neutralized with a 5% aqueous ammonia solution to obtain an acrylic emulsion type polymer. The solid content was 50%. This acrylic emulsion polymer was used as B-2 liquid.

The liquid A obtained in Example 1, the liquid B-2 obtained as described above, and the chemitite DZ-22E were (acrylic polymer: Pencel D160: super ester S100) = (100: 5: 10) and mixed, and 0.15 parts by weight of Chemitite DZ-22E (Nippon Shokubai Co., Ltd., aziridine-based cross-linking agent) in solid content was added.
It was coated on an ET film (thickness of 38 μm) and dried to prepare an adhesive tape having a thickness of the adhesive layer of 25 μm.

(Example 6) The amount of Pencel D160 added to the liquid B-2 of Example 5 was 15 parts by weight, the amount of ion-exchanged water for emulsification was 55 parts by weight, (acrylic polymer: Pencel D160: super ester). S100) = (100:
15:10), and the addition amount of Chemitite DZ-22E was adjusted to 0.
An adhesive tape was produced in the same manner as in Example 5 except that the amount was changed to 25 parts by weight.

(Example 7) The amount of Pencel D160 added in the solution B-2 of Example 5 was 15 parts by weight, the amount of ion-exchanged water for emulsification was 55 parts by weight, (acrylic polymer: Pencel D160: super ester). S100) = (100:
15:20), and the addition amount of Chemitite DZ-22E was adjusted to 0.
An adhesive tape was produced in the same manner as in Example 5 except that the amount was changed to 35 parts by weight.

Comparative Example 1 (acrylic polymer: tackifying resin) = (100:
0), that is, an adhesive tape was prepared in the same manner as in Example 1 except that only the solution B was used.

Comparative Example 2 B as an acrylic polymer
Liquid, using Super Ester E-7 as tackifying resin
40 (Emulsion of Superester S-100, manufactured by Arakawa Chemical Co., Ltd.), (acrylic polymer: tackifying resin) = (100: 30), Chemitite DZ-22E
An adhesive tape was produced in the same manner as in Example 1 except that the amount was 0.3 part by weight.

(Comparative Example 3) In a 1 liter reactor equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube,
80 parts by weight of ion-exchanged water in which 0.1 part by weight of ammonium persulfate was dissolved was added and heated to 70 ° C. under a nitrogen atmosphere. As the monomer composition, n-butyl acrylate 56
Parts by weight, 40 parts by weight of 2-ethylhexyl acrylate,
30 parts by weight of a purified rosin ester resin (super ester S-100 manufactured by Arakawa Chemical Co., Ltd.) having a softening point of 100 ° C. is dissolved in a mixed monomer of 2 parts by weight of acrylic acid and 2 parts by weight of methacrylic acid, and EO-added mole is used as an emulsifier. 1.0 part by weight of an anionic emulsifier obtained by adding a propenyl group to polyoxyethylene nonyl phenyl ether (Aqualon HS-10, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and EO addition mole number 20
0.5 parts by weight of a nonionic emulsifier obtained by adding a propenyl group to polyoxyethylene nonylphenyl ether (Aqualon RN-20 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 50 parts by weight of ion-exchanged water are added, and mixed and stirred. The mixture was emulsified, and the emulsified monomer was charged into the dropping funnel and added dropwise over 3 hours while maintaining the inside of the reactor at 70 ° C. to carry out polymerization. After the completion of dropwise addition of the emulsified monomer, the temperature was maintained at 70 ° C. for 1 hour, the temperature was further raised to 90 ° C., and the reaction was performed for 2 hours. Then, this polymerization liquid was cooled to 30 ° C. or lower and then neutralized with an aqueous 25% ammonia solution to obtain an acrylic emulsion type polymer to which a tackifying resin was added.

To the obtained pressure-sensitive adhesive composition, 0.3 part by weight of solid content of an aziridine-based crosslinking agent (Chemite DZ-22E manufactured by Nippon Shokubai Co., Ltd.) was added to prepare a PET film (38 μm).
(Thickness) and then dried to prepare an adhesive tape having an adhesive layer thickness of 25 μm.

(Comparative Example 4) Without using the solution A of Example 4,
An acrylic emulsion-type pressure-sensitive adhesive consisting of only the B liquid, in which the Pencel D160 was not used in the preparation of the B liquid, the addition amount of ion-exchanged water was changed from 45 parts by weight to 40 parts by weight, and Chemitite DZ-22E ( Solid content of the above).
An acrylic emulsion pressure-sensitive adhesive was prepared in the same manner as in Example 4 except that the amount was reduced to 15 parts by weight and added.
An adhesive tape was prepared in the same manner as in Example 4.

(Comparative Example 5) Superester E740 was added to the acrylic polymer of Comparative Example 4 as a tackifying resin.
(Arakawa Chemical Co., Ltd., Super Ester S100 emulsion) and Super Ester E650 (Arakawa Chemical Co., Ltd.,
A PET film (38 μm thick) was prepared in the same manner as in Comparative Example 4 except that (Acrylic polymer: super ester E740: super ester E650) = (100: 15: 10) was mixed. ) The coating is dried and the thickness of the adhesive layer is 2
A 5 μm adhesive tape was prepared.

(Comparative Example 6) Without using the liquid A of Example 4,
An acrylic emulsion-type pressure-sensitive adhesive consisting only of solution B, wherein in the preparation of solution B, the addition amount of Pencel D160 dissolved in the monomer mixture was changed from 5 parts by weight to 25 parts by weight, and Chemitite DZ-22E (see above) was used. 4) except that the solid content was increased to 0.35 parts by weight.
An acrylic emulsion pressure-sensitive adhesive was prepared in the same manner as in 1. and an adhesive tape was prepared in the same manner as in Example 4.

The emulsion and the pressure-sensitive adhesive tape obtained by the above method were evaluated according to the following methods. Measurement method 1) Emulsion characteristics (1) Solid content Take 1.5 g of the emulsion in an aluminum cup and leave at 110 ° C.
For 3 hours, and the ratio of the dry weight to the emulsion was defined as the solid content. Solid content (%) = [(dry weight (g)) / 1.5 (g)]
× 100 (2) Polymerization stability The emulsion prepared by the above method was filtered through a 100-mesh stainless steel wire net and dried at 110 ° C. for 3 hours, and the ratio of the residue on the wire net to the total solid weight was calculated by the following formula. . Polymerization stability (%) = [(residual dry weight (g)) / (emulsion total weight (g)) × (solid content (%))] × 100 (3) Mechanical stability Marlon type mechanical stability tester (Made by Kyowa Interface Chemical Co., Ltd., emulsion / latex mechanical stability measurement-recorder CM
(S-A type), 25 g of ion-exchanged water was added to 25 g of emulsion to make 50 g, the mixture was rotated at 1000 rpm for 5 minutes under a pressure of 10 Kg / cm 2, and then the aggregate in the container was filtered with a 100 mesh wire mesh. Then, it was dried at 110 ° C. for 3 hours, and the ratio of the dry weight to the total solid content was calculated by the following formula. Mechanical stability (%) = [(residual dry weight (g)) / 25
(G) x (solid content (%))] x 100

2) Physical properties of tape (1) Fraction of gel 1.5 g of an adhesive was weighed in a 50 ml sample tube and 4
Add 0 ml of THF and shake on a shaker for 3 hours. It was filtered through a 200-mesh wire net and dried at 110 ° C. for 3 hours to give a gel residue. Gel fraction (%) = [(residual dry weight (g)) / 1.5
(G)] × 100

3) Adhesive Physical Properties (1) Against SUS Peeling Force 1 against a stainless steel plate according to JIS Z 1528
The 80 ° peeling adhesive strength was measured. (2) Peeling force against PP The 180 ° peeling adhesive force to a polypropylene plate was measured according to JIS Z 1528. (3) Moisture heat retention capacity: 40 mm, 90% RH atmosphere, pasting area: 20 mm
A load of 1 kg was applied at × 20 mm, and the shift length after 1 hour was measured. For those that could not be held for 1 hour, the drop time was measured.

[0052]

[Table 1]

[0053]

[Table 2]

Comparative Examples 1 and 4 are systems in which no tackifying resin is added. The peeling force is inferior as compared with the examples.
Comparative Examples 2 and 5 are prepared by mixing the tackifying resin emulsions after the completion of emulsion polymerization. Mechanical stability and wet heat retention are inferior as compared with the examples. In Comparative Examples 3 and 6, emulsion polymerization was performed in the coexistence of a tackifying resin. Polymerization stability and peeling force are slightly inferior to those of the examples.

[0055]

The acrylic emulsion-type pressure-sensitive adhesive of the present invention, having the above-mentioned constitution, has high pressure-sensitive adhesive property, high water resistance and high coating property.

Claims (3)

[Claims] 1. At least one represented by (i) the general formula CH2 = CR1 --COOR2 (wherein R1 represents hydrogen or a methyl group, and R2 represents an alkyl group having 4 to 14 carbon atoms). 90 to 98% by weight of one kind of (meth) acrylic acid ester and 10 to 2% by weight of at least one kind of monomer selected from the group consisting of a monomer containing a carboxyl group, a monomer containing an amide group and a monomer containing a hydroxyl group, as essential components. 100 parts by weight of the acrylic copolymer, and
(Ii) An acrylic emulsion-type pressure-sensitive adhesive comprising 5 to 100 parts by weight of a tackifying resin, the (meth) acrylic acid ester, and a group consisting of a carboxyl group-containing monomer, an amide group-containing monomer and a hydroxyl group-containing monomer. Polymer (A) obtained by dropwise polymerization of a monomer mixture of at least one selected from a tackifier resin emulsion emulsified with an emulsifier, the (meth) acrylic acid ester, and a carboxyl group-containing monomer An acrylic emulsion type characterized by being obtained by mixing with a polymer (B) obtained by emulsion polymerization of a monomer mixture consisting of at least one selected from the group consisting of an amide group-containing monomer and a hydroxyl group-containing monomer. Adhesive. 2. At least one represented by (i) the general formula CH2 = CR1 --COOR2 (wherein R1 represents hydrogen or a methyl group, and R2 represents an alkyl group having 4 to 14 carbon atoms). 90 to 98% by weight of one kind of (meth) acrylic acid ester and 10 to 2% by weight of at least one kind of monomer selected from the group consisting of a monomer containing a carboxyl group, a monomer containing an amide group and a monomer containing a hydroxyl group, as essential components. 100 parts by weight of the acrylic copolymer, and
(Ii) An acrylic emulsion-type pressure-sensitive adhesive comprising 5 to 100 parts by weight of a tackifying resin, the (meth) acrylic acid ester, and a group consisting of a carboxyl group-containing monomer, an amide group-containing monomer and a hydroxyl group-containing monomer. Polymer (A) obtained by dropwise polymerization of a monomer mixture of at least one selected from a tackifier resin emulsion emulsified with an emulsifier, the (meth) acrylic acid ester, and a carboxyl group-containing monomer A polymer (B) obtained by emulsion-polymerizing a monomer mixture comprising at least one selected from the group consisting of an amide group-containing monomer and a hydroxyl group-containing monomer in a state in which a tackifying resin is dissolved in the monomer mixture. An acrylic emulsion-type pressure-sensitive adhesive obtained by mixing. 3. The emulsifier has the following chemical formula [1]:
The acrylic emulsion-type pressure-sensitive adhesive according to claim 1 or 2, which is at least one selected from the group consisting of [2], [3] and [4]. Embedded image In the formula, R1 and R2 each represent an alkyl group having 6 to 18 carbon atoms, an alkenyl group, or an aralkyl group. m is 8 to 4
The integer of 0 and n represent the integer of 8-40. A represents an alkylene group having 2 to 4 carbon atoms or a substituted alkylene group.
M represents an alkali metal ion, an ammonium ion, or an alkanolamine ion.