JPS60166366A - One-pack type aqueous emulsion adhesive composition - Google Patents

Abstract

PURPOSE:The titled composition, obtained by incorporating a specific acrylic copolymer emulsion with a specific polyglycidylamine-containing emulsion, containing the polyglycidylamine protected with a tackifier as a crosslinking agent, and having improved moisture resistance, etc. CONSTITUTION:A one-pack type aqueous emulsion adhesive composition obtained by incorporating (A) an aqueous emulsion prepared by emulsion polymerizing a monomeric mixture consisting of >=50wt% acrylic acid ester, preferably methyl acrylate and 0.1-15wt% alpha,beta-unsaturated carboxylic acid, e.g. acrylic acid, with (B) an aqueous emulsion of a solution obtained by dissolving a polyglycidylamine, e.g. N,N-diglycidylaniline, and a tackifier inert thereto, e.g. a petroleum based hydrocarbon resin, in a hydrophobic organic solvent, e.g. toluene, and/or a plasticizer, e.g. dioctyl phthalate. USE:A pressure-sensitive adhesive for adhesive tapes, labels, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in acrylic aqueous emulsion adhesives, and more particularly to a one-component acrylic aqueous emulsion adhesive composition containing polyglycidylamine as a crosslinking agent.

Acrylic water-based emulsion adhesives are used as pressure-sensitive adhesives when producing adhesive tapes, labels or sheets.
It is also widely used as an adhesive for bonding synthetic resins, wood, etc., and for laminating films, paper, etc. Acrylic water-based emulsion adhesives can be roughly divided into deep type and two-component type. Although the former has the advantage of being easier to use than the latter,
Since performance such as moisture resistance and heat resistance is generally inferior, two-component products are usually used for applications that require higher performance.

The two-component acrylic water emulsion adhesive consists of an aqueous emulsion obtained by copolymerizing acrylic acid ester with a small amount of α,β-unsaturated carginic acid, polyisocyanate,
It is an adhesive that is used in combination with a crosslinking agent such as polyepoxide or polyglycidylamine, and since this type of adhesive contains a crosslinking agent, it is natural that
Demonstrates performance superior to conventional one-component adhesives. However, two-component adhesives have the disadvantage that the pot life is relatively short because the crosslinking reaction begins to proceed from the time the crosslinking agent is mixed into the aqueous emulsion of the acrylic copolymer.

In view of the advantages and disadvantages of conventional acrylic water-based emulsion adhesives as listed above, the present inventors discovered that although a crosslinking agent is blended, one-component acrylic water-based emulsion adhesives As a result of repeated research to develop a polyglycidylamine '6 that functions as a crosslinking agent,
．． When dissolved in a hydrophobic organic solvent and/or plasticizer together with a tackifier inert to tr-glycidylamine, and the resulting solution is dispersed in water in the form of droplets, polyglycidylamine becomes tacky. Since it is protected by an imparting agent, it will not react with water and lose its crosslinking ability, and even if this aqueous emulsion is mixed with an aqueous emulsion of an acrylic copolymer, the water as a dispersion medium will not volatilize. It has been found that the cross-linking reaction does not take place unless there is .

Therefore, the one-component acrylic aqueous emulsion adhesive composition according to the present invention contains 5 Q of acrylic acid alkyl esters.
Contains at least 0.0 wt% of α,β-unsaturated carcinic acid.
Aqueous emulsion obtained by emulsion polymerization of a monomer mixture containing 1 to 15 wt%, polyglycidylamine and a tackifier inert to polyglycidylamine, and a hydrophobic organic solvent and/or It is a mixture of an aqueous emulsion of a solution dissolved in a plasticizer.

The aqueous emulsion (A) is a monomer mixture containing acrylic acid alkyl ester and α,β-unsaturated carzenic acid as essential components, and blending these with other copolymerizable vinyl monomers as necessary. It is prepared by emulsion polymerization in a conventional manner, but the monomer mixture must not contain 5 Q wt% or more of acrylic acid alkyl ester and 0.1 to 15 wt% of α,β-unsaturated carzenic acid. No.

This is because if the amount of acrylic acid ester is less than 50 wt%, the adhesive force and adhesive force will decrease, and if the amount of α,β-unsaturated carbenoic acid exceeds 15 wt%, the adhesive force will decrease.

The weight average molecular weight of the acrylic copolymer obtained by emulsion polymerization is preferably 10,000 or more, particularly 100,000 to 1,000,000 from the viewpoint of performance.

Examples of acrylic acid alkyl esters include alkyl acrylates having C1 to C,t alkyl groups, such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, indityl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate. Preference is given to using esters. α.

As the β-unsaturated carnoic acid, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, etc. can be used. In addition, other copolymerizable vinyl monomers that may be used as necessary include methyl methacrylate,
Examples include ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, acrylamide, N-methylol acrylamide, vinyl acetate, vinyl propionate, styrene, acrylonitrile, 2-hydroxy methacrylate, and ethylene glycol dimethacrylate.

For aqueous emulsions, polyglycidylamine and a tackifier inert to polyglycidylamine are dissolved in a hydrophobic organic bath agent and/or plasticizer, and this solution is added to water in the coexistence of a surfactant. Emulsions are prepared by dispersing and spitting.

Polyglycidylamine has two epoxy groups in the molecule.
Compounds having one or more tertiary nitrogen atoms are used, specifically N,N-diglycidylaniline, N,
N-diglycidyl toluidine, m-N-N-diglycidylaminophenyl glycidyl ether, triglycidyl in cyanurate, N-N-N'・N'-tetraglycidylethylenediamine, N-N-N'-N'-tetra Glycidylaminodiphenylmethane, N・N, N/・
N'-tetraglycidyl-m-xylylene diamine is a typical example of the polyglycidylamine used in the present invention. The tackifier is preferably a hydrophobic one that does not contain any functional group such as a kyfur group or an amino group that reacts with polyglycidylamine, especially one with a softening point of 70 to 15.
A tackifier having a carbon content of about 0''C is preferable.Specifically, petroleum-based hydrocarbon resins, terpene resins, and modified products thereof can be used as the tackifier.

As the hydrophobic organic solvent, aromatic hydrocarbons such as toluene and xylene, and aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane are usually used.

Typical hydrophobic plasticizers include dioctyl phthalate, dibutyl phthalate, dioctyl adipate, and terpene plasticizers. In addition, "hydrophobic" in relation to organic solvents and plasticizers means that the solubility of water at 20°C is Q.
, l means less than 1 wt%.

When preparing the aqueous emulsion of the present invention, the relationship between the amount of polyglycidylamine used and that of the tackifier is extremely critical, especially when the amount of tackifier used is insufficient relative to the polyglycidylamine. Since the polyglycidylamine cannot be sufficiently protected from water, it is not possible to obtain a one-component adhesive which is the object of the present invention. Therefore, when preparing the aqueous emulsion (13), it is possible to use 4 M parts or more of the tackifier per 1 part by weight of polyglycidylamine.

The amount of the hydrophobic organic bath agent or plasticizer to be used can be selected arbitrarily, but in general, the amount of hydrophobic organic bath agent or plasticizer i
It is practical to use about 0.2 to 2 double portions.

The mixing ratio of aqueous emulsion/(A) and (A) is 0.0001 to 0.5 equivalent, preferably 0.001 to 0.0, per equivalent of carzexyl group contained in the acrylic copolymer of the aqueous emulsion. .1 equivalent of epoxy groups, the proportion that can be supplied by the polyglycidylamine in the aqueous emulsion Φ).

The one-component acrylic aqueous emulsion adhesive composition of the present invention is comprised of a mixture of the above-mentioned aqueous emulsion (4) and, unlike the conventional -G type ice-water emulsion adhesive, it contains a crosslinking agent. However, since the crosslinking agent is protected by the tackifier, the crosslinking ability is not lost during storage. Incidentally, the one-component adhesive composition of the present invention shows no change in quality even after being stored at 40° C. for 6 months, and exhibits the same performance as at the time of preparation. In addition, since the one-component adhesive composition of the present invention contains a crosslinking agent, it has temperature resistance and heat resistance comparable to conventional two-component acrylic water-based emulsion adhesives, and therefore It can be widely used not only as a pressure sensitive adhesive but also as an ordinary adhesive.

This will be explained below using examples.

Examples 1 to 3 and Comparative Examples 1 to 3 A. Production method of acrylic copolymer emulsion Sodium lauryl sulfate 1 part (hereinafter expressed in parts by weight) Ion exchange water 5
0 part Potassium persulfate 0.2 part was charged into a reaction vessel, the temperature was raised to 75°C while nitrogen gas was flowing, and the next monomer emulsion vIJ was added dropwise over 3 hours.

Emulgen 930 (product of Kao Soap Co., Ltd.) 2 parts ion exchange water 49 parts dibutyl acrylate 50 parts 2-ethylhexyl acrylate 47 parts acrylic acid 3
After the dropwise addition of 0.1 part of t-dodecyl mercaptan, the temperature was maintained at 75°C for 3 hours to complete the reaction. After cooling to room temperature, add ammonia water to adjust the pH.
7.0 to 7.5 to obtain an acrylic copolymer emulsion with a nonvolatile content of 50%.

B, J Process for producing emulsion containing liglycidylamine Dissolve and mix 50 parts of toluene and moisture-retaining power to form polyglycidyl. Amine-containing emulsion C)
get.

Mix appropriate amounts of Φ) with (c)), apply to a 25 μm thick polyester film so that the coating thickness after drying is 25 μm, dry at 100°C for 2 minutes, cover with release paper and leave at room temperature for a certain period of time. The following performance was measured as a post-pressure sensitive adhesive.

Adhesive strength Based on the adhesive strength of JIS Z-0237-1980 (180 degree peeling method).

Holding force According to JIS Z-0237-1980 (7) Holding force, the load is set to 1 hour, and the falling time of the load or the distance after 60 minutes is measured at 40"C.

Measured at an inclination angle of 30 degrees according to JIS Z-0237-1980 (ball rolling method).

The same test as the holding power was conducted at 30"C and 85% relative humidity.

Test y similar to holding force (measured in an atmosphere of so℃.

Shown in 1.

(Leaving space below) Example 4 and Comparative Example 4 Manufacturing method of acrylic copolymer emulsion 1.4 parts of sodium lauryl sulfate 35 parts of ion-exchanged water 0.2 parts of potassium persulfate were charged into a reaction vessel and heated for 75 minutes while flowing nitrogen gas. The temperature was raised to 0.degree. C., and the following monomer emulsion was added dropwise over 3 hours.

Zotyl acrylate 96 parts Methacrylic acid 2 parts Vinyl acetate 2 Toden-dodecyl mercaptan 0.06 g Nucol 5
06 (Nippon Nyukazai (Rin Co., Ltd.) 2 parts ion exchange water 43
After completing the addition, the temperature was maintained at 75°C for 3 hours to complete the reaction. After cooling to room temperature, add ammonia water to pi
(Adjust to 7.0-7.5.

Acrylic copolymer emulsion with non-volatile content of 55% (A
') get.

B' Manufacturing method for polyglycidylamine-containing emulsion 50 parts of cyclohexane Dissolve and mix 5 parts of xylylene/diamine, and mix with 2 parts of Emulgen 931 and 100 parts of ion-exchanged water to prepare a polyglycidylamine-containing emulsion (B
′) is obtained.

An appropriate amount of (B') was mixed with (in), and the performance was measured under the following conditions.

[Adhesion method]

Base Wood adhering material Apply 30x foamed polyethylene 7 (10 mm thick) Brush 150 g/m” wet onto wood and dry 2
Pressure bonded at 0℃ for 20 minutes at 65% H
Measured with continuous bombardment at m/min.

Water resistant adhesive strength After curing, immerse in water at 20°C for 7 days and measure immediately after taking out in the same way as normal adhesive strength.

Heat-resistant adhesive strength After curing, leave in an atmosphere at 60°C for 20 minutes, then measure at 60°C in the same way as normal adhesive strength.

The performance is shown in Table 2.

Table-2

Claims (1)

[Claims] 1. A one-component aqueous emulsion adhesive composition prepared by mixing the following aqueous emulsions 4 and 0) (c)) Containing 5Qwt% or more of acrylic acid alkyl ester, α, β-
Aqueous emulsion obtained by emulsion polymerization of a monomer mixture containing 0.1 to 15 wt% of unsaturated carboxylic acid 03) Polyglycidylamine and a tackifier inert to polyglycidylamine are hydrophobicized. Aqueous emulsions of solutions dissolved in organic solvents and/or stabilizers