JPH0723461B2 - Two-component chloroprene adhesive - Google Patents

Description

TECHNICAL FIELD The present invention relates to a two-pack type chloroprene adhesive, and more specifically,
In particular, the present invention relates to a solvent two-component type chloroprene-based adhesive which is suitable for adhesion of polyolefin foam and exhibits excellent adhesive strength and heat resistance when applied to an adherend on one side.

Problems to be Solved by the Prior Art Among various rubber adhesives, chloroprene adhesives based on chloroprene rubber are usually applied to a wide range of applications, for example, used for manufacturing door trims in automobile assembly production lines. Has been done. Door trims are made of ABS resin or plastic composite materials (for example, polypropylene mixed with wood powder or waste paper, polypropylene hardwood with wood chips, wood, or fibres) as the core material. Of polyvinyl chloride sheet or film laminated polyolefin film, foamed polyvinyl chloride skin layer, polyvinyl chloride or woven fabric laminated polyurethane film) by vacuum forming or press forming. For this adhesion, a solvent two-component type chloroprene-based adhesive consisting of a chloroprene rubber, a tackifying resin, an organic solvent as a main component, and an isocyanate-based curing agent has recently been adopted. However, although it has a tentative effect in terms of spray workability and initial adhesive strength, for example, when the skin material is the above-mentioned polyolefin foam, since the polarity of the foam is low,
Adhesive properties that are not fully satisfactory cannot be obtained, and heat resistance is particularly poor.
Strength and creep properties under high temperature load become weak. For this reason,
It was necessary to apply an adhesive to both surfaces of the adherend (core material and skin material), and it was necessary to subject one of the adherends to a primer treatment or plasma irradiation in advance.

Therefore, the present inventors do not need pretreatment such as primer treatment even when bonding such polyolefin foam, and are a two-component chloroprene adhesive that exhibits sufficient adhesive strength and heat resistance by one-side coating. As a result of intensive research to provide the desired adhesive, the intended adhesive can be obtained by specifying the type (or characteristics) of chloroprene rubber, tackifying resin and isocyanate curing agent, and the rubber / resin compounding ratio. This has led to the completion of the present invention.

Structure and Effect of the Invention That is, the present invention provides (a) Mooney viscosity [ML (1+
4) 100 ° C.] 100 to 30 parts by weight of chloroprene rubber having a crystallization rate of 30 to 130 and a moderate to fast crystallization rate (the same applies hereinafter),
(B) As a tackifying resin, a mixture of an alicyclic resin and a chelating reaction product of an alkylphenol resin and a metal oxide, the weight ratio in terms of resin being 1/1 to 3/1 20 to A two-component chloroprene-based adhesive characterized by comprising a main agent containing 50 parts by weight and (c) an aliphatic and / or alicyclic polyisocyanate compound as a curing agent.

As the chloroprene rubber (a) in the present invention,
Various commercial products are manufactured and sold by, for example, Showa Neoprene Co., Ltd., Denki Kagaku Kogyo Co., Ltd., Toyo Soda Kogyo Co., Ltd., and especially Mooney viscosity [ML (1 + 4) 100
C.] 30 to 130, preferably 40 to 120 and having a moderate to fast crystallization rate. If the Mooney viscosity is less than 30, the initial cohesive force at the time of laminating will be insufficient and the initial adhesive strength will be lacking.If it exceeds 130, the heat obtained during vacuum forming will not sufficiently soften the adhesive and single-sided adhesion will occur. Sex decreases.

As the alicyclic resin which is one of the tackifying resins (b) in the present invention, a cyclopentadiene resin is particularly preferable. Further, the chelation reaction product used in combination therewith,
For example, it can be obtained by adding a metal oxide (such as magnesium oxide) to a toluene solution of an alkylphenol resin (such as t-butylphenol resin) and reacting at a temperature of 30 to 60 ° C. for 12 to 48 hours. In the present invention, an alicyclic resin and a chelation reaction product (hereinafter referred to as a chelated phenol resin) are used in a mixture in which the weight ratio in terms of resin content is 1/1 to 3/1. The amount used (in a mixture) is selected within the range of 20 to 50 parts, preferably 30 to 40 parts, per 100 parts of the chloroprene rubber (a). If it is less than 20 parts, the adhesiveness at the time of laminating will be deteriorated, and the one-sided property will be deteriorated.
When the amount exceeds the range, the polarity of the adhesive increases and the adhesiveness with the polyolefin foam decreases.

In addition to the tackifying resin (b), a usual terpene-modified phenol resin, t-butylphenol resin,
An appropriate amount of coumarone-indene resin, rosin resin, etc. may be added.

Hexamethylene diisocyanate is particularly preferable as the aliphatic polyisocyanate compound of the curing agent (c) in the present invention. Further, examples of the alicyclic polyisocyanate compound used in place of or in combination therewith include 4,4′-dicyclohexylmethane diisocyanate, modified isophorone diisocyanate, cyclohexylmethane diisocyanate, and modified hexamethylene diisocyanate.

It is noted that, unlike these polyisocyanate compounds, aromatic compounds having a high polarity cannot achieve the desired effect (see Comparative Example 2 below).

The two-component chloroprene-based adhesive according to the present invention comprises the above-specified proportions of chloroprene rubber (a) and tackifying resin (b) in a suitable organic solvent (for example, aromatic such as toluene or xylene, acetone, MEK, MIBK). Etc., a main agent dissolved in a ketone system, an alicyclic system such as cyclohexane, a chlorinated hydrocarbon system such as trichloroethylene), and the above curing agent (c). The main agent may be prepared according to a usual roll kneading method or a direct dissolution method, and a usual vulcanizing agent or vulcanization accelerator (magnesium oxide (commonly called magnesia), zinc white, etc.), a filler, etc. , Plasticizers, anti-aging agents and the like may be added in appropriate amounts.

The use of the adhesive of the present invention is not limited to the adhesion of the above-mentioned polyolefin, but like other chloroprene adhesives, other plastic materials, wood,
It goes without saying that it can be applied to various adherends such as metal and leather.

Next, the present invention will be described more specifically with reference to Examples and Comparative Examples.

Examples 1 to 6 and Comparative Examples 1 to 4 Preparation of Chelated Phenolic Resin 10 parts of t-butoxyphenol resin (Tamanol 520 manufactured by Arakawa Chemical Co., Ltd.) was dissolved in 15 parts of toluene, and 1 part of magnesia was added thereto. Then, chelation reaction is carried out at 40 to 50 ° C for 15 hours or more to obtain 26 parts of chelated phenol resin solution.
This is used as it is.

Preparation of Two-Component Chloroprene Adhesive In each of the components shown in Table 1, chloroprene rubber is kneaded with magnesia and activated zinc white for 20 times with a mixing roll. On the other hand, an organic solvent is put in a tank, and then the above-mentioned rubber paste is put in and dissolved. A tackifier resin is added to this, and the mixture is stirred and dissolved at 40 ° C. for 12 hours to obtain a main component. The target isocyanate is prepared by blending the polyisocyanate compound shown in Table 1 with the main component.

Adhesion test Polypropylene foam (Toray KK, Toraypek PP)
X AW60 25030) is coated with the above adhesive at 150 g / m ² , and this is attached to an ABS resin plate to prepare an adhesion test piece. After curing and curing this test piece at 20 ℃ and 65% RH for 72 hours, the normal adhesive strength (kg / 25mm) and the adhesive strength (heat aging resistance) under heating atmosphere of 100 ℃ × 168 hours are measured and 110 ℃ separately. A 200 g load is applied to one end of the foam side in the atmosphere of, and a 24-hour creep test is performed to measure the peel length (heat-resistant creep). The test results are shown in Table 1.

Continuation of the front page (56) References JP-A-50-39335 (JP, A) JP-A-53-59733 (JP, A) JP-A-54-152034 (JP, A) "Adhesion Handbook (Japanese) Second Edition) "Nikkan Kogyo Shimbun (Sho 55-11-10) P. 330-332

Claims (4)

[Claims] (A) Mooney viscosity [ML (1 + 4) 100
[° C.] 30 to 130 and moderate to fast crystallization rate 100 parts by weight of chloroprene rubber, and (b) an alicyclic resin as a tackifying resin, and an alkylphenol resin and a chelate reaction product of a metal oxide, A main component containing 20 to 50 parts by weight of a mixture having a weight ratio in terms of resin of 1/1 to 3/1, and (c) an aliphatic and / or alicyclic polyisocyanate compound as a curing agent A two-component chloroprene-based adhesive. 2. The adhesive according to claim 1, wherein the alicyclic resin of the tackifying resin (b) is a cyclopentadiene resin. 3. The adhesive according to claim 1, wherein the chelating reaction product of the tackifying resin (b) is a chelating reaction product of a t-butylphenol resin and magnesium oxide. 4. A curing agent (c) wherein the aliphatic polyisocyanate compound is hexamethylene diisocyanate and the alicyclic polyisocyanate compound is 4,4'-dicyclohexylmethane diisocyanate or isophorone diisocyanate or a modified product thereof. Adhesive described.