JPH0798875B2 - Chloroprene copolymer composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a chloroprene copolymer composition, and more particularly to a chloroprene copolymer composition useful as a substrate for solvent-based adhesives. The present invention relates to a composition containing a copolymer of a chloroprene monomer and a carboxyl group-containing vinyl monomer and an epoxy functional group-containing compound.

[Conventional technology]

A method for obtaining a chloroprene copolymer by emulsion polymerization of a chloroprene monomer and a vinyl monomer having a carboxyl group such as acrylic acid or methacrylic acid is known (Japanese Patent Publication No. 43-6067). Such a copolymer is used for applications in which a normal chloroprene copolymer is used, particularly used for producing a solvent-based adhesive, and a solvent-based adhesive using this chloroprene copolymer is known to have high adhesive strength. There is
44-9959).

However, this chloroprene copolymer has the following problems as compared with general chloroprene polymers for adhesives.

(1) Viscosity stability as a chloroprene copolymer is poor.

(2) When the metal oxide required as an adhesive is kneaded, it easily gels.

(3) Viscosity stability is poor when the solvent-type adhesive is dissolved with other compounding aids.

(4) When preparing a solvent-based adhesive using this copolymer, there is a great limitation in the selectivity of the resin and the solvent.

Due to these problems, there are great restrictions on use, and therefore the development of fields of use has not progressed.

[Problems to be solved by the invention]

An object of the present invention is to solve the problems of viscosity stability and processing stability, solvent and resin selectivity of conventional carboxylic acid-chloroprene copolymers.

[Means for solving problems]

As a result of diligent study by the inventor on such problems, it was found that the above problems can be solved by adding a compound having an epoxy functional group to a copolymer of a carboxyl group-containing vinyl monomer and chloroprene.

That is, the present invention provides a chloroprene copolymer composition comprising 100 parts by weight of a chloroprene monomer, a carboxyl group-containing vinyl monomer copolymer and 0.05 to 5 parts by weight of a compound having an epoxy functional group. To do.

Hereinafter, the present invention will be described in more detail.

Examples of the vinyl group-containing vinyl monomer constituting the copolymer used in the present invention include acrylic acid, methacrylic acid, maleic acid, fumaric acid, etc., and 0.1 to 5 of the total amount of monomers in the case of producing the copolymer is used. Mol%, preferably 0.5-2.6 mol% is used.

As a copolymer of the chloroprene monomer and the carboxyl group-containing vinyl monomer used in the present invention, in addition to these monomers, if necessary, a monomer copolymerizable with the chloroprene monomer, for example, 2,3-dichlorobutadiene-1 1,3,1-chlorobutadiene-1,3, styrene, sulfur, acrylonitrile, methyl methacrylate, etc., one or more kinds of monomers, based on the total amount of the monomer,
Copolymers obtained by substituting the chloroprene monomer and polymerized within a range not exceeding the weight% are also included.

When obtaining the copolymer used in the present invention, the polymerization method is not particularly limited, and for example, emulsion polymerization may be carried out in an acidic atmosphere as shown in the conventional technique.

The emulsion polymerization will be described below.

As the emulsifier, for example, an alkali metal salt of alkylbenzene sulfonic acid having 6 to 18 carbon atoms, an alkali metal salt of formalin condensate of β-naphthalene sulfonic acid, polyoxyethylene alkyl ether and the like are used.

The chain transfer agent is not particularly limited, and alkyl mercaptan, dialkyl xanthogen disulfide, etc. are used, and the polymerization initiator may be one used in ordinary radical polymerization, for example, benzoyl peroxide, potassium persulfate and the like.

The polymerization temperature and the conversion rate of the monomer are not particularly limited, but the polymerization temperature is 0 to 60 ° C., preferably 20 to 40 ° C., and the monomer conversion rate is in the range of 60 to 90%. Good.

As the polymerization terminator, a commonly used terminator such as thiodiphenylamine, 4-tert-butylcatechol, diethylhydroxyamine and the like can be used.

The compound having an epoxy functional group used in the present invention is not particularly limited, but it is a compound having at least one or more epoxy functional groups in the molecule, such as an alkyl glycidyl ether (for example, Kyoeisha Oil and Fat trade name Eporite). M-1230, NOF CORPORATION trade name Epiol A), glycerin-based glycidyl ether (eg Epolite 100M)
F, Dainippon Ink &Petrochemical's trade name Epicron EXP312,
Nagase &Co.'s trade name Denacol EX-611), alicyclic diglycidyl ether (eg Epolite 4000, Epiclon)
850, trade name Epicoat 828 of oiled shell epoxy, trade name Epomic R-140 of Mitsui Petrochemical Epoxy, polycarboxylic acid ester-based glycidyl ether (e.g. Epicron 400, Epicoat 190), polyalkylene glycol diglycidyl ether (e.g. Epolite 200P,
E, Denacol EX-832, Epiclon 720) and the like. The amount of addition is 0.05 to 5.0 parts by weight, preferably 0.1 to 2.0 parts by weight, based on 100 parts by weight of the copolymer of carboxyl group-containing vinyl monomer and chloroprene. If it is less than 0.05 parts by weight, the effect of the addition is not sufficient, and if it is more than 5 parts by weight, the original properties of the chloroprene adhesive such as the adhesive strength are impaired. The addition method is not restricted. For example, when a copolymer is produced, the epoxy functional group-containing compound can be added to the polymerization system before or during the polymerization, or can be added to the copolymer after the polymerization by any method. In particular, in the case of emulsion polymerization, even if the epoxy functional group-containing compound is allowed to be present before the start of the polymerization of the copolymer, or even before the start of the polymerization and immediately before freezing the copolymer emulsion for drying. If it is added at any time, the effect can be obtained, but taking workability into consideration, the method of adding it to the copolymer emulsion together with the polymerization terminator is preferable because it is not complicated.

Although the mechanism for improving the stability of the carboxylated chloroprene copolymer in the present invention is not clear, it is estimated as follows. First, regarding the stability of viscosity,
It is presumed that even if dehydrochlorination occurs due to the attack of the chloroprene structure portion by the carboxyl group in the chloroprene copolymer, the generated hydrochloric acid is captured by the epoxy compound and the adverse effect on the chloroprene copolymer is eliminated. Regarding the stability to the metal oxide, it is presumed that the ring-opening reaction of the epoxy compound takes precedence over the ring-closing reaction of the carboxyl group by the metal oxide, which is considered to be the cause of gelation.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples together with Comparative Examples, but the present invention is not limited to these Examples. In the text, parts represent parts by weight unless otherwise specified.

Polymerization of the carboxylic acid-chloroprene copolymer used in this example was carried out in a 4-necked flask of 5 while continuously dropping dropwise potassium persulfate at a polymerization temperature of 40 ° C. in a nitrogen atmosphere.

The polymerization recipes of copolymers I and II are shown in Table 1.

When the conversion of the monomer reached about 85%, diethylhydroxylamine was charged as a polymerization terminator and 100 ppm was added to the total amount of the monomer to terminate the polymerization. This copolymer emulsion was divided and added with epoxy functional group-containing compounds of different types and amounts.

A 2% NaOH aqueous solution was added to the obtained copolymer emulsion to adjust its pH to 9.0, and unreacted monomers were removed by a steam stripping method. Add 5% acetic acid solution
After adjusting the pH to 7.0, it was solidified with a freezing drum, washed with water and dried.

In this example, as the epoxy functional group-containing compound, the following three types were used.

Epolite 200P (trade name of Kyoeisha fats and oils) b. Epolite 100MF (same as above) c. Epikote 828 (trade name of oiled shell epoxy) For Examples 1 to 5 and Comparative Examples 1 to 3, carboxylic acid-
The compounding recipe of the chloroprene copolymer and the epoxy functional group-containing compound is shown in Table 2, and their physical properties are shown in Tables 2 and 3.

Examples 1 to 5 show excellent results in terms of both viscosity stability and adhesive strength, whereas Comparative Examples 1 and 2 have markedly poor viscosity stability.
In Comparative Example 3, the adhesive strength is obviously insufficient.

The method of measuring each physical property in the table will be described below.

A. Storage stability of raw rubber A chloroprene copolymer-epoxy compound composition (hereinafter often referred to as "chloroprene rubber") is left at 25 ° C in a thermostatic chamber and taken out at predetermined intervals in the table. Mooney tester (Shimadzu Corporation) The viscosity of ML1 + 4 (100 ° C.) was measured according to the above method. 0th is just after production.

B. Solution stability Chloroprene rubber, antioxidants, MgO, and ZnO were kneaded and mixed by an ordinary method with an 8-inch open roll so as to obtain the "blend" shown in Table 4.

Similarly, as shown in "Resin solution" in Table 4, a resin / MgO solution was prepared by dissolving the resin in toluene and water and adding MgO, and then reacting at 25 ° C for 20 hours. To this solution was added the above formulation and n
-A solvent consisting of hexane and ethyl acetate was added and mixed and stirred to obtain an adhesive.

Put this adhesive in a tin can with epoxy coating on the inside, seal the lid with solder, and then in a constant temperature water bath at 60 ° C.
The solution viscosity was measured at 25 ° C. by using a Brookfield viscometer.

C. Normal adhesive strength 150 × 25 mm, No. 10 canvas, 75 × 25 mm area, with the adhesive obtained by the same method as in B above, brushed in 3 times, and after 30 minutes, 2 sheets as a set Lamination: The 10 pbs roller was reciprocated 5 times for pressure bonding. After leaving this test piece at 23 ° C. for a predetermined period in the table, the peel strength was determined using an autograph (manufactured by Shimadzu Corporation) at a speed of 50 mm / min in the same temperature atmosphere.

D. Heat resistance After holding a test piece obtained in the same manner as in C at 23 ° C for 10 days,
The peel strength was determined in the same manner as in C while keeping the temperature of the constant temperature bath at the predetermined temperature in the table.

E. Solution stability depending on the type of compound Chloroprene rubber, so that it becomes the "composition" shown in Table 5.
The antioxidant, MgO and ZnO were kneaded and blended by an ordinary method with an 8-inch open roll. On the other hand, the resin and the solvent were preliminarily dissolved so as to have a combination of types shown in the table to give a "resin solution".

The above formulation was aged for 1 week at 40 ° C in a constant temperature bath.
Add the compound before aging (initial) and the compound after aging (after standing) to the above resin solution, mix and stir to make an adhesive, and measure the solution viscosity at 25 ° C using a Brookfield viscometer. It was measured.

Table 4 Compounds Chloroprene rubber 100 parts Anti-aging agent 2 MgO 4 ZnO 5 Resin solution Resin ^* 40 MgO 4 Toluene 160 Water 1 Solvent n-Hexane 160 Ethyl acidate 160 * Resin = CKM1634 (trade name of Showa Union Synthesis) No. Table 5 Compounds Chloroprene rubber 100 parts Anti-aging agent 2 MgO 4 ZnO 5 Resin solution Resin ^* 40 MgO 4 Solvent ^** 362 * Resin types are as shown in Table 3. However, Tamanol 526 was used in the solvent type test.

** Solvent types are as shown in Table 3. However, a solvent of toluene / acetone = 79/21 was used when testing the resin type.

Claims (1)

[Claims] 1. A copolymer of a chloroprene monomer and a carboxyl group-containing vinyl monomer or a copolymer of a chloroprene monomer, a carboxyl group-containing vinyl monomer and 10% by weight or less of another monomer, and 100 parts by weight of an epoxy functional group. A chloroprene copolymer composition comprising 0.05 to 5 parts by weight of a compound.