JPH08302315A - Aqueous two-part adhesive for vacuum molding of polyolefin foamed sheet - Google Patents

Abstract

PURPOSE: To obtain an aq. two-part adhesive, having excellent heat resistance after curing, which enables adhesion in vacuum molding of a polyolefin foamed sheet by comprising: a main agent composed of a predetermined rubber latex and a tackifier as indispensable components; and a particular curing agent. CONSTITUTION: This aq. two-part adhesive comprises a main agent comprising a carboxyl-modified chloroprene rubber and a tackifier (e.g. rosin resins) as indispensable components; and an emulsion type curing agent contg. an oxazoline group (e.g. CX-WS-120), manufactured by Nippon Shokubai Kagaku Kogyo, Co., Ltd.). Pref., the amt. of the tackifier used on a solid basis is 5 to 100 pts.wt. (hereinafter referred to as 'pts.') based on 100 pts (on a solid basis) carboxyl- modified chloroprene rubber latex, and the amt. of the curing agent used is 3 to 30 pts. based on 100 pts. main agent.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a water-based two-component adhesive, more specifically, a carboxyl-modified chloroprene rubber latex, a mixed water-based emulsion main agent of a tackifier, and an oxazoline group-containing emulsion type curing agent. It has excellent adhesiveness to a polyolefin foam sheet and heat resistance after curing, and has a usable time (the usable time here is the time from applying and drying the adhesive to laminating. As expected, the present invention relates to an aqueous two-component adhesive having a long pot life.

[0002]

2. Description of the Related Art Conventionally, water-based two-component type adhesives generally used have a polyurethane emulsion as a main component and a water-dispersible isocyanate and an aqueous emulsion main component mixed with a tackifier. It is an aqueous two-component adhesive as a curing agent, and has the drawbacks that initial adhesion to a polyolefin foam sheet is difficult and that the pot life and pot life are short. Furthermore, in an aqueous two-component adhesive containing a carboxyl-modified chloroprene rubber latex and a tackifier as a mixed aqueous emulsion main agent and a water-dispersible isocyanate as a curing agent, a curing agent in an amount necessary for obtaining desired heat resistance is added. There was a problem that the initial adhesion was lowered. Therefore, initial adhesion, heat resistance after curing, pot life, and pot life are required for vacuum forming adhesion of a polyolefin foam sheet, and a water-based adhesive satisfying all the characteristics has been desired.

[0003]

Accordingly, the present invention provides the above-mentioned carboxyl-modified chloroprene rubber latex with a water-based adhesive having an initial adhesiveness and a heat resistance after curing, which is a polyolefin-based foam without impairing pot life and pot life. As a result of intensive studies to develop adhesiveness equivalent to or more than solvent-type adhesives capable of vacuum forming adhesion, the use of an oxazoline group-containing emulsion as a curing agent yields an aqueous two-component adhesive for the initial purpose. I came to find out that it is possible to be.

The carboxyl-modified chloroprene rubber latex in the present invention is a chloroprene rubber having at least one carboxyl group in the chloroprene rubber molecule and is an unsaturated aliphatic organic carboxylic acid capable of copolymerizing a chloroprene monomer with the chloroprene rubber. , For example, acrylic acid, methacrylic acid, itaconic acid and the like by copolymerization by an emulsion polymerization method.

Examples of tackifiers include hydrogenated rosin, polymerized rosin, maleic acid-modified rosin, hydrogenated rosin ester, and other rosin-based resins, alkylphenol resins, rosin-modified phenolic resins, terpene-modified phenolic resins, and other phenolic resins. Natural and synthetic terpene resin, coumarone-indene resin, coumarone-indene-styrene resin,
Aliphatic and aromatic petroleum resins can be used, and rosin resins, phenolic resins, and terpene resins are particularly preferable.

The amount of the tackifying resin used (in terms of solid content) may usually be set in the range of 5 to 100 parts by weight per 100 parts by weight of the carboxyl-modified chloroprene rubber latex. If it is less than 5 parts or more than 100 parts, the desired initial adhesion cannot be obtained, and the heat resistance after curing tends to decrease.

The following monomers having an oxazoline group can be used for the crosslinking agent containing an oxazoline group used in the present invention. For example, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl. 2-oxazoline and the like can be used alone or in combination of two or more. Further, as the monomers having these oxazoline groups, the following vinyl monomer components can be used as a copolymerization component. The vinyl monomer component is not particularly limited as long as it is copolymerized with oxazoline and does not interact with oxazoline, for example, methyl acrylate, butyl acrylate, acrylic acid esters such as 2-ethylhexyl acrylate, Unsaturated nitriles such as acrylic acid nitrile, vinyl acetates such as vinyl acetate and vinyl propionate, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, α-such as ethylene and propylene.
Examples include α, β-unsaturated aromatic monomers such as olefins, vinyl chloride, vinylidene chloride and vinyl fluoride,
These 1 type or 2 types or more can be used.

The aqueous two-pack type adhesive agent according to the present invention comprises a two-pack type of a main agent consisting of the carboxyl-modified chloroprene rubber latex and the tackifying resin in the above-mentioned predetermined proportions, and an oxazoline group-containing emulsion type hardening agent. Just before use, measure and mix the base compound and the curing agent. If necessary, an ordinary thickener is added to the main agent so that the viscosity of the main agent is usually 10
You may adjust to 00-10,000 cps / 20 degreeC. The amount of the curing agent used is usually set in the range of 3 to 30 parts by weight with respect to 100 parts by weight of the main agent (solid content conversion).
If it is less than 3 parts by weight or more than 30 parts by weight, sufficient heat resistance after curing cannot be obtained, and the adhesiveness tends to decrease.

[0009]

EFFECT OF THE INVENTION The adhesive of the present invention having the above constitution exhibits good initial adhesive properties and heat resistance after curing, has a long pot life and a long pot life, and is capable of vacuum forming and adhering a polyolefin foam sheet. It is possible.

[0010]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Examples 1 and Comparative Examples 1 to 3 (1) Main Agent A carboxyl-modified chloroprene rubber latex or urethane emulsion in the number of parts shown in Table 1 below, and a tackifier and a thickener were blended to obtain a main agent. (2) Crosslinking agent An oxazoline group-containing emulsion (manufactured by Nippon Shokubai Co., Ltd., CX-WS-
120) 5 parts or Polymeric MDI (manufactured by Nippon Polyurethane Company, Coronate 3053) 5 parts were mixed to prepare an adhesive.

(3) Adhesion test After the adhesive of the above (2) was thoroughly stirred and mixed and left at room temperature for 2 hours, it was applied on a wooden board at an amount of 150 g / m ² and dried at 80 ° C. for 5 minutes. After that, the open time was taken for 30 minutes, and a foamed polypropylene sheet preheated to 140 ° C. was pressure-bonded thereto at a pressure of 0.5 kg / cm ² for 15 seconds to prepare a test piece. Then, provide the following test items,
The results are also shown in Table 1.

Initial peel strength Immediately after laminating, tensile speed is 200 mm / min, 25 mm width, 1
The 80 degree peel strength (kg / 25 mm) was measured. Immediately after the initial heat-resistant creep bonding, a load of 100 g / 25 mm was applied at 90 degrees in an atmosphere of 80 ° C., and the peel length (mm) after 1 hour was measured. 8 hours after curing at 20 ℃ and 65% RH for 24 hours after laminating normal heat resistant creep
In a 0 ° C. atmosphere, a load of 100 g / 25 mm was applied at 90 degrees, and the peeling length (mm) after 24 hours was measured.

[0013]

[Table 1] Note 1) Electrochemical Co., LC-501, solid content 47% Note 2) Bayer Co., Dispercoll KA-8
464, solid content 40% Note 3) Yoshimura Yushi Kagaku, Yucarezin KE-904, solid content 55% Note 4) Hoechst, Borchigel L-75 Note 5) A is a polypropylene polypropylene sheet interface peeling, B is material destruction

Claims (2)

[Claims] 1. A water-based composition comprising a base compound containing a carboxyl-modified chloroprene rubber latex and a tackifier as essential components, and an oxazoline group-containing emulsion type curing agent, which enables vacuum forming adhesion of a polyolefin foam sheet. Two-component adhesive. 2. The amount of the tackifying emulsion (in terms of solid content) is 5 to 100 parts by weight based on 100 parts by weight of the solid content of the carboxyl-modified chloroprene rubber latex, and the amount of the curing agent used is based on 100 parts by weight of the main agent. The aqueous two-component adhesive according to claim 1, which is 3 to 30 parts by weight.