JPS61275315A - Production of chloroprene copolymer - Google Patents

Abstract

PURPOSE:To produce the titled copolymer useful for bonding PVC, urethane, nylon or the like containing a large amount of a plasticizer, by radical-graft- polymerizing a monomer with a specified chloroprene rubber latex in water. CONSTITUTION:A chloroprene rubber latex is obtained by polymerizing 100pts. wt. chloroprene or mixture thereof with a copolymerizable monomer (e.g., sty rene) at 0-100 deg.C in an alkaline emulsion in the presence of 0.05-10pts.wt. styrenesulfonic acid derivative of formula I (wherein R is H, a halogen, hydroxyl group or a 1-4C hydrocarbon group, and Y is H, K, Na or quat. ammonium) to a conversion of 60% or higher. 10-100pts.wt., per 100pts.wt. rubber, monomer of formula II (wherein R' is H or a 1-4C hydrocarbon and R'' is a 1-12C hydrocarbon) is radical-graft-polymerized in water with the above latex at 30-100 deg.C in the presence of a polymerization initiator to a conversion of 50% or higher, and the reaction mixture is dropped into a large amount of water containing a salting-out agent to precipitate the polymer.

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, ☆rethane, 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 it is extremely difficult to control both at the same time and requires a high degree of skill and intuition. Therefore, the production of this adhesive is limited to specific manufacturers in specific regions, and it has not been 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 extremely low) viscosity.
The types of solvents that can be used for grafting are naturally limited.

On the other hand, the type and composition of the solvent affects the adhesive properties, and it is often necessary to use a special solvent composition to bond specific materials. This may interfere with the adhesion of materials.

[Problem that the invention seeks to solve]

The present invention provides a method for producing a roloprene copolymer that 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, the present invention uses chloroprene alone or a mixture of chloroprene and a copolymerizable monomer with 100 parts or 1 carbon number.
~4 hydrocarbon group, X is a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 4 carbon atoms, and Y is a hydrogen atom and potassium.

For chloroprene rubber latex obtained by polymerization in an alkaline emulsion in the presence of 5 to 10 parts by weight of a styrene sulfonic acid derivative represented by sodium or quaternary ammonium, per 100 parts by weight of the rubber content. 10 to 100 parts by weight of 2〇H, -OR'-C! 0-
Aqueous radical graft polymerization of at least one monomer of (in the formula, R' is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and f is a hydrocarbon group having 1 to 12 carbon atoms) It depends on K.

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

The chloroprene rubber latex used in the present invention is generally a hydrocarbon group of 80 and Y 4 based on 100 parts by weight of chloroprene alone or a mixture of chloroprene and a copolymerizable monomer, and X is a hydrogen atom, a halogen atom,
a hydroxyl group or a hydrocarbon group having 1 to 4 carbon atoms, and Y is a hydrogen atom, potassium, sodium, or quaternary ammonium) Styrene sulfonic acid derivative Q, 0
It is obtained by polymerization in an alkaline aqueous emulsion in the presence of 5 to 10 parts by weight.

Monomers copolymerizable with chloroprene include 1-chlorobutadiene and 2,3-dichlorobutadiene.

There are butadiene, styrene, acrylonitrile, alkyl methacrylate, etc., and these can be used up to 20% by weight. Examples of styrenesulfonic acid or its derivatives include p-styrenesulfonic acid, its sodium salt, and potassium salt.

There are quaternary ammonium salts, sodium α-methyl-p-styrenesulfonate, sodium 0-chloro-p-styrenesulfonate, and these may be used alone or in combination of two or more. The amount used is 105 to 10 parts by weight, preferably α1 to 5 parts by weight, per 100 parts by weight of chloroprene or a mixture of monomers copolymerizable with it. If this amount is less than 105 parts by weight, the effect on the adhesive strength of soft PVC etc. will be small. The effect is sufficient up to 10 parts by weight, and it is uneconomical to use more than 10 parts by weight.

Surfactants used to form the emulsion include surfactants commonly used in the polymerization of chloroprene, such as unmodified rosin acids, disproportionated rosin acids, and the like.

Alkali metal salts or ammonium salts of aliphatic carboxylic acids, alkylbenzenesulfonic acids, etc. are used.

As the molecular weight regulator, commonly used alkyl mercaptans, alkyl kitentogen 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 alkaline 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% 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 OH, -cRLco-OR#C, and the number of carbon atoms is 1.
-4 hydrocarbon group or hydrogen, f has 1 to 1 carbon atoms
It has a structure of 2 hydrocarbon groups),
These can be used alone or in combination of two or more. 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 an amount exceeding 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.

Although it is not necessary to use a surfactant in particular in the graft reaction, the surfactant used in the production of the chlorobrane/rubber latex can be used if necessary.

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

Polymerization is carried out at a temperature of 50° to 100° C1, preferably 60°-9
The reaction is carried out at 0°C until a conversion of at least 50% is reached, and a polymerization inhibitor such as phenothiazine or 2,6-theta-jarybutylhydroxytoluene is added to terminate the polymerization. If the polymerization temperature is low, a homopolymer will be mainly produced, resulting in a low grafting rate and a decrease in adhesive strength, so it is necessary to carry out the polymerization at a temperature of 30° C. or higher. Furthermore, if the polymerization temperature is high, the storage stability of the obtained chloroprene copolymer will decrease, so the polymerization temperature is preferably 90° C. or lower.

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. All you have to do is add the agent.

[Effect]

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, etc., and its industrial value is extremely high. Furthermore, since it is only necessary to dissolve the adhesive in an organic solvent, it is possible to arbitrarily select the type and composition of the solvent in the adhesive solution, 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 4. Comparative Example 1) A mixed aqueous solution of α5% potassium persulfate and sodium anthraquinone-β-sulfonate α05 as a polymerization catalyst was added to an autoclave equipped with a stirrer at the composition ratio shown in Table 1. Polymerization was carried out at 10°C under a nitrogen stream, and when the conversion was about 88%, phenothiazine [LOI part,
Polymerization was stopped by adding 15 parts I part of tertiary-butylcatechol.

After removing the remaining unreacted monomers using the steam fludge method, the temperature of the latex was raised to 800°C, and the rubber content was reduced to 1.
Methacrylic acid methyl ester (MMA) 4 to 00 parts
0 parts were added dropwise. After the dropwise addition was completed, 0.2 parts of sodium metabisulfite and 140 parts of potassium persulfate were added to initiate polymerization.

After polymerization was completed for about 5 hours, 1.0 part of phenothiazine and 15 parts of tert-butylcatechol were added as stabilizers. Then, a large amount of calcium chloride aqueous solution was pressed to precipitate the polymer, which was then filtered, washed with water, dehydrated, and dried to isolate the grafted chloroprene copolymer.

Next, the obtained polymer was dissolved in toluene, and the solid content was 15
% adhesive liquid was prepared. Then, using the adhesive solution,
The adhesion strength between polyvinyl chloride sheets containing dioctyl phthalate and the adhesion strength with an 8BR rubber sheet were measured in the following manner.

To 100 parts by weight of a 151 part adhesive solution dissolved in an organic solvent, 5 parts of a trifunctional incyanato compound (Dymosier RF methylene chloride solution) was added as a hardening agent, and after thorough mixing, a test piece with a width of 25 ats was prepared. After applying each product with a brush and allowing 10 to 15 minutes of open time,
Paste them together and press. 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 (a-40s) (Toyo Soda Kogyo Membrane), a solution graft reaction of MMA was carried out at the composition ratio shown below.

C! R (G-408) 100 parts Toluene 800 parts MMA 60 parts BPO 2 parts For polymerization, after raising the temperature to 80°C, 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 10 parts of tert-butylcatechol were added to stop the polymerization.

The conversion rate of MMA was 68%, and the viscosity of the obtained grafting solution was 5600 apa at 25°C. As in Examples 1 to 4, adhesive strength was measured using soft PVC and 8BR rubber as raw materials.

The results are summarized in Table-2.

As is clear from Table 2, the amount of p-styrene sulfonate/sodium acid added during chloroprene polymerization has an effect on adhesive strength, and even with the addition of a very small amount, a remarkable improvement in adhesive strength can be seen, compared to the solution-grafted product. Adhesive strength equivalent to or higher than that obtained can be obtained. It is also seen that there is almost no change in solution viscosity and the storage stability is excellent.

(Examples 5 to 7) Polymerization of chloroprene and graft polymerization of MMA were carried out in the same manner as in Examples 1 to 4 using the composition ratios shown in Table 3.
A tIb toluene solution was prepared and the adhesive strength was measured.

The results are summarized in Table 4.

Table 4 (Examples 8 to 10. Comparative Examples 3 to 4) Graft polymerization was carried out in the same manner as in Example 3 using the chloroprene rubber latex of Example 5 and changing the amount of MMA at the composition ratios shown below. The results of the preparation and measurement of adhesive strength are summarized in Table 5.

From Table 5, the effects of the present invention are clear. Comparative example 5 is M
Because the amount of MA 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.

However, Comparative Example 4 was pre-filled with chloroprene rubber, and P-M
Good adhesive strength can be obtained when the MA/chloroprene rubber ratio is 20 to 807,100.

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, R is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, x is a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 4 carbon atoms, and Y is a hydrogen atom, potassium, sodium, or quaternary ammonium) for a chloroprene rubber latex obtained by polymerizing in an alkaline emulsion in the presence of 0.05 to 10 parts by weight of a styrene sulfonic acid derivative represented by 10 to 100 parts by weight per 100 parts by weight of the rubber with the formula CH_2=CR'CO-OR'' (wherein R' is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and R'' is a carbon number 1
1. A method for producing a chloroprene copolymer, which comprises carrying out aqueous radical graft polymerization of at least one monomer of 1 to 12 hydrocarbon groups.