JPS60203683A - Adhesive - Google Patents

Abstract

PURPOSE:A one-pack adhesive suitable for bonding polyolefin, etc., having improved water-resistant and heat-resistant bond strength, comprising an ethylene- vinyl ester multi-copolymer emulsion and a polyurethane emulsion. CONSTITUTION:(A) An ethylene-vinyl ester multi-copolymer emulsion obtained by subjecting (i) 5-35wt% ethylene, (ii) 2-50wt% vinyl acetate, and (iii) 35-90wt% total amount of a higher carboxylic acid vinyl ester (preferably vinyl pivalate, etc.) and an acrylic ester (e.g., butyl acrylate, etc.) (with the proviso that a weight ratio of the former to the latter of 100:0-60:40) to emulsion polymerization preferably by the use of PVA as an emulsion dispersant is blended with (B) a polyurethane emulsion (preferably anionic emulsion), to give the desired adhesive. A ratio of solid content of the component A:B is usually 95:5-60:40.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous contact adhesive, and more particularly, an aqueous contact adhesive containing a sulfethylene-vinyl ester multi-component copolymer emulsion having a specific copolymer composition and a polyurethane emulsion. The present invention relates to a one-component water-based contact adhesive that has characteristics of excellent water resistance and heat resistant adhesive strength, and also exhibits excellent adhesive strength to polyolefin adherends. Contact adhesives are used to bond similar or different types of abrasive materials, such as rubber, metal, and plastic, by applying an adhesive to an adherend, letting it dry, then bonding and pressing. Conventionally, organic solvent-based chloroprene-based contact adhesives have been used, but safer water-based contact adhesives are required for reasons such as health and safety, air pollution, and fire hazards.

In response to these demands, some acrylic acid ester emulsions have been put on the market as water-based contact adhesives, but they are not satisfactory in terms of water-resistant adhesion (in addition, rubber and polyethylene emulsions, whose use has expanded in recent years) The contact property itself was insufficient for polyolefin-based adherends, such as foam, which are generally said to have poor adhesive properties.On the other hand, ethylene-acetic acid was used as a simple pressure-sensitive adhesive for polyolefin-based adherends. Vinyl-higher carboxylic acid vinyl ester copolymer emulsions and ethylene-vinyl acetate-higher carboxylic acid vinyl ester-acrylic acid ester copolymer emulsions have been proposed (Japanese Patent Publication No. 12653/1983, JP-A-52 -4
No. 7833, Japanese Unexamined Patent Publication No. 73235/1983),
When used as a contact adhesive, heat resistance and water resistance adhesive strength were not fully satisfied. In addition, a composition in which an isocyanate compound is added to an ethylene-vinyl ester copolymer emulsion has been proposed as a water-based contact adhesive for the purpose of improving heat-resistant and water-resistant adhesive strength, but the adhesive is in a two-component form. This was not desirable in terms of workability, as it required mixing immediately before use.

In order to solve the problems of such contact adhesives, the present inventors conducted intensive studies and found that the contact adhesive is characterized by containing a specific ethylene-vinyl ester multi-component copolymer emulsicon and a polyurethane emulsion. The water-based adhesive has excellent contact properties as well as water and heat resistant adhesion for non-polyolefin adherends as well as polyolefin adherends, and can take the form of a one-component type with excellent workability. They found this and completed the present invention.

That is, the present invention contains 5 to 35 wt% of ethylene, 2 to 5 percent of vinyl acetate, the total amount of higher carboxylic acid vinyl ester and acrylic ester is 3 to 9 characters, and the total amount of higher carboxylic acid vinyl ester and acrylic ester is Weight ratio is 1
The present invention provides an aqueous contact adhesive characterized by containing an ethylene-vinyl ester multicomponent copolymer emulsion having a copolymer composition of 0:0 to 60:40 and a polyurethane emulsion.

The ethylene content in the copolymer of the ethylene-vinyl ester multi-component copolymer emulsion used in the present invention is 5
-35 Wt'S, and if it is less than 5 wt%, the contact properties of the polyolefin adherend will be poor, and if it is more than 35 Wt'S, it will be poor in heat resistance. In addition, the vinyl acetate content in the copolymer is 2-
If the amount is less than 2 wt%, the stability of the copolymer emulsion is poor, and if it is more than 50 wt%, the contact property is poor.

The copolymer in the copolymer emulsion used in the present invention has a total content of vinyl higher carboxylic acid Nisder and acrylic ester of 35 to QQwt, and a weight ratio of 100:0 to 60:40. The total content is asw
If it is less than ts, the contact properties will be poor, and if it is more than 9 Qwt%, the stability of the emulsion when mixed with polyurethane will be poor.

Furthermore, if the ratio of higher carboxylic acid vinyl ester and acrylic ester is out of the above range, contact properties tend to be poor, which is not preferable.

The higher carboxylic acid vinyl ester used in the present invention is preferably a higher carboxylic acid having 5 to 12 carbon atoms, such as vinyl pivalate, vinyl laurate, or vinyl persate (Veo*a-10 manufactured by Niji Engineering Chemical Co., Ltd.). used. Examples of the acrylic ester used in the present invention include acrylic esters derived from alcohols having 4 or more carbon atoms, such as butyl acrylate, pentyl acrylate, octyl acrylate, and 2-ethylhexyl acrylate.

The multicomponent copolymer of the present invention contains the above-mentioned monomers in the above-mentioned amounts, in addition to the above-mentioned monomers, vinyl esters such as vinyl propionate and vinyl butyrate, diester maleate, and fumaric acid. Copolymerization of diester etc. may also be used, and furthermore, hydroxyl group, amide group, carboxyl group, etc.
It may contain a monomer containing a functional group such as a sulfonic acid group, an epoxy group, an alkoxy group, or a methylol group in an amount of 1Qwt or less.

The ethylene-vinyl ester multi-component copolymer emulsion used in the present invention is produced by a normal emulsion polymerization method, and the emulsifying dispersant used at this time is polyvinyl alcohol because of its suitability for application when used as an adhesive. is preferred. As polyvinyl alcohol, those having an average saponification degree of 70 to 99.5 mol and an average polymerization degree of 200 to 2,700, which are generally used as emulsifying dispersants, or those modified with carboxylic acid, sulfonic acid, glyoxal, etc. are used as polyvinyl alcohol. In addition, hydroxyethylcellulose-based protective colloids, nonionic and anionic emulsifiers may be used in combination.

The present invention is an adhesive characterized by containing such an ethylene-vinyl ester multi-component copolymer emulsion and a polyurethane emulsion, the solid content ratio of which is usually in the range of 95:5 to 60:40. It is. Polyurethane emulsions are emulsified by introducing new water groups into the main chain or side chains of urethane resins, and are anionic polyurethane emulsions containing sulfonates or carboxylates, ethylene-vinyl ester-based polyesters, etc. It is preferably used because of its stability with polymer emulsions.

In the present invention, additives used in general water-based adhesives, such as thickeners, solvents, tackifiers, pigments, etc., may be added to the emulsion as necessary.

The thus obtained adhesive of the present invention has excellent not only contact properties but also water resistance, heat resistance, and adhesive strength, and is a one-component adhesive with excellent workability, so it can be used with polyolefins such as medium rubber and polyethylene foam. cloth, paper, wood,
Can be used for bonding between similar or dissimilar materials such as mortar metals.

The present invention will be specifically explained below using examples.

Example 1 2.5 parts by weight and 1.5 parts by weight of partially saponified polyvinyl alcohol with an average degree of saponification of 88 mol, an average degree of polymerization of 500 and an average degree of polymerization of 1,700, respectively, and a nonionic emulsifier (polyoxyethylene nonyl Emulsion polymerization was carried out under ethylene pressure using 1.5 parts of phenyl ether) per 100 parts by weight of the total amount of monomers other than ethylene,
Copolymer composition: ethylene 15wt%, vinyl acetate 8wt%
, Veoba-10 69wt '16, acrylic acid 2
-Ethylhexy 8 wt%, resin solid content 50.5 WE%
An emulsion of a multi-component copolymer was obtained. Hytran HW-3 per 100 parts by weight of resin solid content of this emulsion.
11 (manufactured by Dainippon Ink Chemical Co., Ltd., resin solid content 45wt)
%.

An adhesive was prepared by adding 15 parts by weight of anionic polyurethane emulsion (in terms of resin solid content). This adhesive was evaluated under the following conditions, and the results are shown in Table 2.

(1) Adhesion conditions εP a) Adhesion of flexible board and hand rubber waterproof sheet Apply adhesive 250 9/lh2 to the flexible board and set the open time to 30 minutes. Press the liquid rubber waterproof sheet once with a hand roller. death,
Cure for one day.

b) Adhesion date P of flexible board and polyethylene foam Perform in the same manner as a) except that polyethylene foam is used instead of the non-rubber waterproof sheet.

C) Adhesion between mild steel plate and canvas Apply adhesive 1209/-2 to each of the degreased mild steel plate and canvas (No. 6), allow 30 minutes of open time, and bond the adhesive-applied surfaces together using a hand roller. Press once and cure for one day.

(2) Adhesion test Normal peel strength angle 180°, speed 20 Qrrrn 1 minute, temperature 2
Measured at 3°C.

The peel strength was measured in the same manner as normal peel strength.

Heat resistance peel strength Measured at a temperature of 50° C., an angle of 180°, and a speed of 200 va/min.

Examples 2 to 5 Emulsion polymerization was carried out in the same manner as in Example 1 to obtain various ethylene-vinylethyl copolymer emulsions shown in Table 1. The polyurethane emulsion shown in Table 1 was added to this in the same manner as in Example 1 to prepare an adhesive, and evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 1 The multi-component copolymer emulsicon obtained in Example 1 was used as it was and evaluated in the same manner as in Example 1 to obtain the results shown in Table 2.

Comparative Examples 2 to 3 Emulsion polymerization was carried out in the same manner as in Example 1 to obtain emulsions having copolymer compositions shown in Table 1. The polyurethane emulsion shown in Table 1 was added to this in the same manner as in Example 1 to prepare an adhesive, and the adhesive was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Claims (1)

[Claims] Ethylene 5-35 wt%, vinyl acetate 2-50 W[%]
, the total amount of higher carboxylic acid vinyl ester and acrylic ester is 35 to 9 Q wt%, and the weight ratio of higher carboxylic acid vinyl ester and acrylic ester is 10
An adhesive characterized by containing an ethylene-vinyl ester multi-element copolymer emulsion having a copolymer composition of 0:0 to 60:40 and a polyurethane emulsion.