JPS6218411A - Production of chloroprene copolymer - Google Patents

Abstract

PURPOSE:To facilitate the production of a chloroprene copolymer suitable as an adhesive for, e.g., a flexible vinyl chloride resin material, by radical-graft- polymerizing an alkyl (meth)acrylate in an aqueous medium with a chloroprene rubber latex of a specified composition. CONSTITUTION:A chloroprene rubber latex is prepared by polymerizing 100pts. wt. chloroprene or mixture thereof with a copolymerizable monomer in an acidic or neutral emulsion in the presence of 0.1-20pts.wt. hydroxyl group- containing polymerizable monomer of formula I (wherein n is 1-20, R is a 1-4C hydrocarbon or H and R' is a 2-3C hydrocarbon), e.g., a compound of formula II. 10-100pts.wt., per 100pts.wt. rubber of the latex, monomer of formula III (wherein R'' is a 1-4C hydrocarbon or H and R''' is a 1-12C hydrocarbon), e.g., butyl acrylate, is radical-graft-polymerized in an aqueous medium with the latex to obtain the purpose chloroprene copolymer.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is useful for adhesives for materials such as polyvinyl chloride (hereinafter referred to as soft vinyl chloride), urethane, and nylon, which contain a large amount of solubilizing agent. The present invention relates to a method for manufacturing a combination.

[Conventional technology]

So-called solution-grafted chloroprene is produced by dissolving chloroprene rubber in a solvent such as toluene or methyl ethyl ketone, adding a monomer such as methyl methacrylate (abbreviated as MMA), and performing graft polymerization using a polymerization initiator such as benzoyl peroxide. Due to its excellent performance, rubber adhesives are widely used industrially in fields related to synthetic shoes made mainly of soft vinyl chloride, urethane, nylon, and the like.

However, this type of solution-grafted chloroprene rubber adhesive has the following problems.

+1) The viscosity of the grafting reaction solution and the polymerization rate of the monomer used for grafting are important items, but controlling both at the same time is extremely difficult and requires a high degree of skill and intuition. For this reason, the production of this adhesive is limited to specific manufacturers in specific regions, and it has not come to be widely used universally.

(2) The viscosity of the grafting reaction solution changes with the grafting reaction. The behavior of this viscosity change differs depending on the graft prescription. For example, the viscosity is greatly affected by the solvent used, with some solvent systems having extremely high or low viscosity. For this reason, the types of solvents that can be used for grafting are naturally limited.

On the other hand, the type 1 composition of the solvent affects the adhesive properties, and it is often necessary to use a special solvent composition to bond specific materials, but there are restrictions on the solvents that can be used due to the above viscosity behavior, so these This may interfere with the adhesion of materials.

[Problem that the invention seeks to solve]

The present invention provides a rolobrene copolymer which does not have the problems of conventional solution-grafted chloroprene rubber adhesives as described above and is useful for bonding soft PVC, urethane, nylon, etc. by simply dissolving it in a solvent. It is in.

[Means to solve the problem]

That is, in the present invention, chloroprene alone or a mixture of chloroprene and a copolymerizable monomer is used, n is an integer of 1 to 20, R is a hydrocarbon group having 1 to 4 carbon atoms, or hydrogen,
Chloroprene rubber obtained by polymerizing in an acidic or neutral emulsion in the presence of 11 to 20 parts by weight of a hydroxyl group-containing polymerizable monomer (y is a hydrocarbon group having 2 or 3 carbon atoms) For latex, 10 to 100 parts by weight per 100 parts by weight of the rubber
At least one monomer of af (in the formula, t is a hydrocarbon group having 1 to 4 carbon atoms or hydrogen, and I is a hydrocarbon group having 1 to 12 carbon atoms) is subjected to aqueous radical blatt polymerization. By letting.

The details of the present invention will be further explained below.

The chloroprene rubber latex used in the present invention has the general formula R CHfC-C! based on 100 parts by weight of chloroprene alone or a mixture of chloroprene and a monomer copolymerizable with it. 0-0(R'O)H (in the formula, n is 1 to 20
, R is a hydrocarbon group having 1 to 4 carbon atoms or hydrogen, and Bi is a hydrocarbon group having 2 or 3 carbon atoms) Presence of 1 to 20 parts by weight of a hydroxyl group-containing polymerizable monomer α under,
Obtained by polymerization in an acidic or neutral emulsion. A monomer copolymerizable with chloroprene is 1-chlorobutadiene.

2.3-dichlorobutadiene, phtadiene, styrene,
There are acrylonitrile, alkyl methacrylate, etc., and these can be used up to 20% by weight.

General formula R ■ CH, -c-c o-o (Examples of hydroxyl group-containing polymerizable monomers represented by R'H70H include (:!H70H-C
O-QC, H40H.

CH, -Q(CH8)-Go-QC,H,OH,(!H
, -C(CH,)-Co-0-0,H,01(.

cH, -c(cH,)-co-o(c,H,o enter C!
H,-C! There are (CH,)-Co-0(C,H40 flat H, etc.), and these are used alone or in combination of two or more kinds.

The amount used is (11 to 20 parts by weight) per 100 parts by weight of chloroprene or a mixture of monomers copolymerizable with it.
Parts by weight are preferably 15 to 10 parts by weight. If this amount is less than 11 parts by weight, the effect on the adhesive strength of soft PVC etc. will be small. The effect is sufficient up to 20 parts by weight, and it is uneconomical to use more than 20 parts by weight.

Surfactants include polyoxyethylene alkyl allyl ether, polyoxyethylene acyl ether, and polyoxyethylene alkyl phenol.

Nonionic surfactants such as sorbitan fatty acid esters,
Cationic surfactants such as alkyltrimethylammonium chloride and polyoxyethylene laurylamine,
Surfactants such as Na salt of dodecylbenzenesulfonic acid, triethanolamine salt, alkylamine salt, sodium lauryl sulfate, and sodium salt of alkyldiphenyl ether disulfonate are used.

As the molecular weight modifier, commonly used alkyl mercaptans, alkyl xanthogen disulfides, etc. are used, and as the polymerization initiator, commonly used organic or inorganic peroxides, such as benzoyl peroxide.

Potassium persulfate etc. are used.

The polymerization is carried out in an acidic or neutral aqueous emulsion at a temperature of 0 DEG to 100 DEG C., preferably 5 DEG to 60 DEG C., until a conversion of at least 60 H is reached, and if necessary, a polymerization inhibitor is added to stop the polymerization. As the polymerization inhibitor, commonly used inhibitors such as phenothiazine and 2,6-di-tert-butylhydroxytoluene are used.

Next, grafting using the above chloroprene rubber latex will be explained. The monomer to be grafted has the formula CH, -c4co-o*" (where f is 1 carbon number
-4 hydrocarbon group or hydrogen, f' has 1 to 4 carbon atoms
It has a structure of 12 hydrocarbon groups), and these can be used alone or in combination of two or more types. Specific examples include methyl methacrylate, propyl methacrylate, octyl methacrylate, ethyl acrylate, and butyl acrylate.

These monomers are the rubber component of chloroprene rubber latex.
It is used in a range of 10 to 100 parts by weight per 00 parts by weight. If the amount is less than 10 parts by weight, the adhesive strength to soft PVC materials etc. will be poor. Although it is possible to use more than 100 parts by weight, it is preferable to use less than 100 parts by weight because the adhesive film becomes too hard and tends to cause poor adhesion. Furthermore, in addition to these monomers, water-soluble monomers such as acrylic acid, methacrylic acid, and maleic acid can also be used in combination, as long as they do not impair the essence of the present invention.

It is not necessary to use a surfactant in the grafting reaction, but if necessary, a surfactant used in the production of the chloroprene rubber latex and/or a resin acid such as unmodified rosin, disproportionated rosin, and their alkali metal salts. Derivatives can be used.

As the polymerization initiator, commonly used organic or inorganic peroxides are used, and as the molecular weight regulator, alkyl mercaptans, alkyl xanthogen disulfides, etc. are used as required.

Polymerization is carried out at a temperature of 30°N, 100°C, preferably 60 (90
C. until a conversion of at least 50% is reached, and then a polymerization inhibitor such as phenothiazine or 2,6-di-tert-butylhydroxytoluene is added to terminate the polymerization.

If the polymerization temperature is low, homopolymers will mainly be produced, resulting in a low grafting rate and a decrease in adhesive strength, so the polymerization temperature should be 30°.
It is necessary to perform the test at C or above. Furthermore, if the polymerization temperature is high, the storage stability of the obtained chloroprene copolymer will be reduced, so the polymerization temperature is preferably 90°C or less.

Next, the emulsion in which the graft reaction has been carried out is poured into a large amount of water containing a salting-out agent such as calcium chloride or magnesium chloride to precipitate the polymer, followed by filtration and drying to obtain a grafted chloroprene copolymer.

To obtain an adhesive for materials such as flexible PVC, urethane, nylon, etc. using the grafted chloroprene copolymer of the present invention, simply dissolve the grafted chloroprene copolymer in an organic solvent, add an adhesive and a stabilizer as necessary. [Operation] According to the present invention, by simply dissolving the grafted chloroprene copolymer in an organic solvent, adhesive performance equivalent to or higher than that of conventional solution grafted products can be obtained.

This is truly surprising, and according to the present invention,
There is no need for conventional complicated grafting reactions, and anyone can easily create an adhesive suitable for soft PVC materials, which has extremely high industrial utility value. In addition, since it is only necessary to dissolve the adhesive in an organic solvent, the type and composition of the solvent of the adhesive liquid can be arbitrarily selected, making it extremely easy to use a specific solvent composition for bonding a specific material.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention (1)
Since it is only necessary to simply dissolve the polymer, anyone can easily create an adhesive suitable for soft PVC materials.

(2) Types and compositions of organic solvents used in adhesives can be selected arbitrarily.

Its advantages are extremely large (very useful in industry).

〔Example〕

The present invention will be specifically explained below with reference to Examples, but it is not limited to these Examples.

In addition, unless otherwise specified in the text, parts and parts are weight units.

(Examples 1 to 3. Comparative Example 1) The composition ratios shown in Table 1 were charged into an autoclave equipped with a stirrer, and potassium persulfate [15% and anthraquinone-β-sulfonic acid sodium α05%] were added as polymerization catalysts. A mixed aqueous solution was added and polymerization was carried out at 10°C under a nitrogen stream, and when the conversion rate was about 80%, phenothiazine [LO1] was added as a terminator.
101 parts of tertiary-butylcatechol were added to stop the polymerization.

After removing the remaining unreacted monomers by a steam flash method, the temperature of the latex was raised to 80" and the rubber content was 10".
Methacrylic acid methyl ester (MMA) 70 parts per 0 parts
portion was added dropwise. After the dropping was completed, 12 parts of sodium metabisulfite and 1.0 part of potassium persulfate were added to initiate polymerization. When the polymerization rate was about 60 cm, 1.0 part of phenothiazine and 15 parts of tertiary-butylcatechol were added as terminators. Polymerization was stopped. After removing the remaining unreacted monomer by steam flash method, pour into a large amount of calcium chloride aqueous solution to precipitate the polymer, filter, rinse with water, dehydrate,
After drying, the grafted Rolopray copolymer was isolated.

Next, the obtained polymer was dissolved in toluene, and the solid content was 1
An adhesive solution No. 5- was prepared.

Next, using the adhesive solution, adhesion between polyvinyl chloride sheets containing 70 dioctyl thiphthalate and adhesion strength with an SBR rubber sheet were measured in the following manner.

Test with a width of 2.5 scm after adding 3 parts of a trifunctional isocyanate compound (Dismodur RF methylene chloride solution) as a hardening agent to 100 parts by weight of a 15% adhesive solution dissolved in an organic solvent and thoroughly mixing. Each piece is coated with a brush, and after 10-15 minutes of open time, they are pasted together and pressed. The adhesive strength was then measured by aging at room temperature and peeling using an Instron tensile tester at a head speed of 100 mm/min.

The obtained results are summarized in Table-2.

(Comparative Example 2) Using commercially available chloroprene rubber (()-408) (manufactured by Toyo Roda Kogyo), a solution graft reaction of MMA was carried out at the composition ratio shown below.

0R (G-408) 100 parts Toluene 800I MMA 70# BPO21 For polymerization, the temperature was raised to 80°C, then 2.0 parts of benzoyl peroxide (BPO) was added to start polymerization, and polymerization was carried out for 7 hours. Thereafter, 1.0 part of phenothiazine and 2.0 parts of tertiary-butylcatechol were added to stop the polymerization. The conversion rate of MMA was 72%, and the viscosity of the resulting grafting solution was 5200 cps at 25°C.

As in Examples 1 to 5, adhesive strength was measured using soft PVC and SBR rubber as raw materials. The results are summarized in Table 2.

口7cho----------'-'-'-'Tel'O
0';0! As is clear from Table 2, CH, -C(CH,)-Co-0-C! added during chloroprene polymerization! H,
C! H and OH are greatly involved in the adhesive strength, and the addition of a small amount of hydrogen significantly improves the adhesive strength, resulting in an adhesive strength equal to or higher than that of the solution-grafted product (Comparative Example 2).

It is also seen that the change in solution viscosity is small and the storage stability is excellent.

(Examples 4 to 6. Comparative Examples 3 to 4) MMAi using the chloroprene rubber latex of Example 3
Graft polymerization was carried out by changing the 15-titoluene solution, and the adhesive strength was measured. The results are summarized in Table 5.

From Table 3, the effects of the present invention are clear. Comparative example 3 is MM
Because the amount of A is too small, and in Comparative Example 4, the amount of MMA is too large and the adhesive film becomes too hard, resulting in poor adhesion and a decrease in adhesive strength.

Claims (1)

[Claims] 1) For 100 parts by weight of chloroprene alone or a mixture of chloroprene and a copolymerizable monomer, general formula ▲ mathematical formula,
There are chemical formulas, tables, etc. ▼ (In the formula, n is an integer from 1 to 20, R is a hydrocarbon group having 1 to 4 carbon atoms or hydrogen, and R' is a hydrocarbon group having 2 or 3 carbon atoms.)
For chloroprene rubber latex obtained by polymerization in an acidic or neutral emulsion in the presence of 0.1 to 20 parts by weight of a hydroxyl group-containing polymerizable monomer represented by ~100 parts by weight of formula CH_2-
CR''-CO-OR''' (in the formula, R'' is a hydrocarbon group having 1 to 4 carbon atoms or hydrogen, and R'' is a hydrocarbon group having 1 to 12 carbon atoms). A method for producing chloroprene copolymerization, which comprises carrying out aqueous radical graft polymerization of at least one type of chloroprene.