KR970010856B1 - Styren-butadiene copolymer latex for adhering rubber - Google Patents

Abstract

The latex having good adhesion is made from the condensation reactant of acrylamide and formaldehyde in the process for making styrene butadiene latex by batch polymerization. Rubber copolymer latex consists of 50-90% by weight of butadiene, 10-40% by weight of styrene and emulsifying agent having 12-20 carbon atoms. Produced emulsion copolymer latex is admixed with resorcinol formaldehyde to use as adhesive. 10-30 parts by weight of resorcinol formaldehyde resin is used on the basis of 100 part by weight of emulsion latex. If the content of resorcinol formaldehyde resin is less than 10 parts by weight, a portion of resin bound to fiber is weakened to lower adhesion, and if the content of the resin is greater than 30 parts by weight, adhesion of resin and fiber is strengthened while adhesion of resin and rubber is weakened. 20-40 g of the copolymer latex as solid is used for 200-400 g of resorcinol formaldehyde aqueous solution, resulting in good adhesion at pH 6-7.

Description

Manufacturing method of styrene-butadiene copolymer latex for rubber product reinforced synthetic fiber adhesive

The present invention relates to a rubber product produced by high temperature emulsion polymerization using at least 5% by weight of a copolymer latex containing styrene-butadiene used as an adhesive of a rubber product and a synthetic fiber, that is, a condensation product of formaldehyde and acrylamide. A method for producing a styrene-butadiene copolymer latex for reinforcing synthetic fiber adhesives.

Conventionally, an aqueous acid solution containing a resorcinol-formaldehyde resin and a latex as a main component is used to bond synthetic fibers and rubber.

The most commonly used part of rubber as an industrial use is tires for automobiles, and there are belts and rubber hoses. These products have characteristics such as high elasticity of rubber, but in order to make up for the weakness of the strength deterioration and deformation easily, the synthetic fiber is bonded between the rubber and the reinforcing action especially in the part requiring strength. Synthetic fibers such as NYLON, POLYESTER, and RAYON, which are used for such reinforcement, have little compatibility with rubber, making it difficult to combine properly. What is necessary to introduce cord paper and cord yarn in rubber materials is RESOCINOL-FORMALDEHYDE LATEX to properly combine rubber with synthetic fiber cord materials such as nylon and polyester which are not compatible at all. (Hereinafter referred to as RFL).

As such latex, a mixed latex of styrene-butadiene copolymer latex and vinylpyridine-styrene-butadiene copolymer latex or natural rubber latex is generally used.

On the other hand, in order to increase the adhesion between the synthetic fibers and rubber, it is desirable to increase the use ratio of the latex in the RFL resin liquid, increase the amount of adhesive attached to the fiber, or develop styrene-butadiene latex having improved adhesion.

The present inventors introduced a condensation reaction of formaldehyde and acrylamide as a crosslinking agent than the styrene-butadiene copolymer latex prepared by the conventional low temperature emulsion polymerization reaction, and the latex produced by the high temperature emulsion polymerization reaction showed higher adhesive strength than the latex used in the prior art. It has been found that the present invention has been completed.

The styrene-butadiene copolymer latex prepared by low temperature emulsion polymerization reaction uses redox-based para-methan hydroperoxide as an initiator, and the reaction is very difficult to control due to the use of a catalyst. There is a problem in the practical use of the reaction, and because it does not contain a condensation reaction of formaldehyde and acrylamide, the adhesion is very low because it does not have a functional group capable of bonding with the amide (amide) group of synthetic fibers such as nylon.

In the present invention, by using a condensation reaction of formaldehyde and acrylamide in a high temperature emulsion polymerization reaction to compensate for the above disadvantages to have an appropriately possible group to significantly increase the adhesive strength of synthetic fibers and rubber products.

That is, the vinyl group is bonded in the polymer main chain and the methylol group is hydrogen-bonded with the amide group of the fiber to give strong adhesion. The present invention provides a method for preparing a latex exhibiting excellent adhesion by introducing a condensation reaction of formaldehyde and acrylamide to the production method of styrene-butadiene latex produced by a batch polymerization method, and a latex prepared by the same method Its purpose is to.

In more detail, an object of the present invention is to provide at least 5 weights of condensation reactants of acrylamide with formaldehyde in providing an adhesive composition having improved adhesion between reinforcing fibers and rubber contained in rubber products such as tires, belts and hoses. It is to provide a styrene-butadiene copolymer latex by high temperature emulsion polymerization containing.

The styrene-butadiene copolymer latex prepared in the present invention has a higher polymerization temperature than the conventional low temperature emulsion polymerization reaction (10 ° C. or lower) and uses a condensation reaction product of formaldehyde and acrylamide, and thus the polymerization temperature in the present invention. Is 40 to 100 ° C. and contains at least 5% by weight of crosslinking agents N-methylolacrylamide and divinylbenzene 2-hydroxysyl 2-methyacrylate.

The rubbery copolymer latex of the present invention is a copolymer latex composed of 50 to 90% by weight of butadiene, 10 to 40% by weight of styrene, and an emulsifier of up to 12 to 20 carbon atoms.

That is, the present invention is a styrene-butadiene copolymer latex prepared by adding ion-exchanged water and an emulsifier. The polymerization temperature is 40 to 100 ° C. and the reaction time is 5 to 20 hours. In addition, methods by semi-batch (SEMI-BATCH) and continuous polymerization are also possible.

In the polymerization, a known method is used using an emulsifier, a polymerization initiator, and a chain transfer agent in an aqueous medium.

Butadiene, which is a monomer used in the present invention, may be substituted with one or two or more kinds of aliphatic conjugated diene monomers such as 2-methyl-1,3-butadiene or conjugated diene monomers such as isoprene in addition to 1,3-butadiene. It is possible. It is also possible to copolymerize some of the styrene with other monomers, for example α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene , 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene. It is possible to copolymerize with monomers, such as monofluorostyrene and hydroxymethylstyrene.

Examples of the emulsifier include anionic surfactants such as alkyl esters of polyethylene glycol, alkylphenyl ethers, and alkyl ether nonionic surfactants, sulfuric acid esters of higher alcohols, alkylbenzene sulfonates, and aliphatic sulfonates.

As the polymerization initiator, water-soluble initiators such as sodium persulfate, potassium persulfate, ammonium persulfate, oil-soluble initiators such as benzoyl peroxide, and redox-based initiators may be used.

As the molecular weight regulator, mercaptans, xyl-disulfides, halogenated hydrocarbons and the like can be used.

Ion-exchanged water is 50 to 200 parts by weight of pure water having an ion exchanger concentration of 2 ppm or less.

The emulsion copolymer latex prepared as the second step may be mixed with the resorcinol-formaldehyde resin and used as an adhesive. Resorcinol-formaldehyde resin is used in an amount of 10 to 30 parts by weight based on 100 parts by weight of the emulsion copolymer latex, and can be used as an adhesive. When the resorcinol-formaldehyde resin is less than 10 parts by weight, the fibers can be bonded. If the part is weak and the adhesive force is lowered and exceeds 30 parts by weight, the adhesive strength of the fiber is strong, but conversely, the adhesive strength with the rubber is lowered.

The copolymer latex thus obtained has excellent adhesion in the pH range of 6 to 7 using 20.0 to 40.0 g as a solid content with respect to 200 to 400 g of the resorcinol-formaldehyde aqueous solution.

Such a characteristic of the copolymer latex of the present invention is a high temperature emulsion polymerization reaction using a condensation reaction of formaldehyde and acrylamide, styrene-butadiene-based copolymer latex is characterized by excellent adhesiveness, tire cord (TIRE CORD) adhesive Widely used.

The following examples are intended to illustrate the present invention in detail, and the present invention is not limited to the following examples.

Example 1

In the first step, the following components were polymerized in a stainless pressure reactor in a suitable ion-exchanged water at a reaction temperature of 40 ℃.

140.0 parts by weight of ion-exchanged water

Potassium rosin 4.0 parts by weight

0.4oz by weight of dodecyl mercaptan

Butadiene 70.0 parts by weight

Styrene 30.0 parts by weight

0.8 parts by weight of potassium persulfate

En methylol acrylamide 2.5 parts by weight

0.2 parts by weight of phosphonic acid

0.5 parts by weight of sodium hydroxide solution

0.3 parts by weight of tamolene

After heating the above-mentioned polymerization mixture to 58 degreeC, 0.4 weight part of sodium bisulfates are inject | poured, and the whole is made into 58 degreeC, and superposition | polymerization is performed. When the polymerization conversion reaches 60%, 0.26 parts by weight of potassium rosinate is added and the temperature is raised to 68 ° C. Then, when the polymerization conversion rate reaches 90%, the polymerization terminator is added to terminate the reaction.

At this time, the pH is 9 ~ 10.5 and distilled under reduced pressure to concentrate the solid content to 40.5% to produce a latex having excellent chemical and mechanical stability.

The weight percent in the present invention is represented by the relative weight percent when the sum of the synthetic resin monomers excluding the emulsifier, initiator, molecular weight modifier and the like is 100.

Here, the monomer composition and dosage ratio of styrene-butadiene copolymer latex, which have a functional group appropriately by using a condensation reaction of formaldehyde and acrylamide by high temperature emulsion polymerization reaction, are shown.

2nd step

The rubber latex obtained in the first step was used to vulcanize the nylon cord and the natural rubber compound.

To the resorcinol-formaldehyde resin solution, 24.7 g of copolymer latex is used as a solid, and the RFL resin solution is made into 18% solids. After aging at room temperature for 20 hours, the nylon cord of 1260 d / 2 is attached. Allow approximately 6% weight. It was immersed under certain conditions, dried at room temperature for 30 seconds, and then heat-treated at 160 ° C. for 5 minutes. The nylon cord thus treated was cut from a natural rubber blend prepared according to the rubber blend prescription of Table 1, and press vulcanized. The adhesion between all tire cords and rubber is evaluated by the H adhesion test method.

Rubber compound prescription

TABLE 1

Example 2.

All reaction conditions are the same as in Example 1, and 2-hydroxyethyl methacrylate is used instead of enmethylol acrylamide, which is a crosslinking agent introduced in the initial stage of the reaction.

Example 3.

All reaction conditions are the same as in Example 1, and divinylbenzene is used instead of enmethylol acrylamide, which is a crosslinking agent introduced in the initial stage of the reaction.

Comparative Example 1 shows the monomer composition and the dosage ratio of the styrene-butadiene copolymer latex by high temperature emulsion polymerization without the condensation reaction of formaldehyde and acrylamide.

1 in comparison.

First step.

The following components were polymerized in an appropriate ion exchanged water at a reaction temperature of 40 ° C. in a stainless pressure reactor.

140.0 parts by weight of ion-exchanged water

Potassium rosin 4.0 parts by weight

0.4oz by weight of dodecyl mercaptan

Butadiene 70.0 parts by weight

Styrene 30.0 parts by weight

0.8 parts by weight of potassium persulfate

0.2 parts by weight of phosphonic acid

0.5 parts by weight of sodium hydroxide solution

0.3 parts by weight of tamolene

After the above-mentioned polymerization mixture was approved at 58 ° C, 0.4 parts by weight of sodium bisulfate was injected and the whole was subjected to polymerization at 58 ° C. When the polymerization conversion reaches 60%, 0.26 parts by weight of potassium rosinate is added and the temperature is raised to 68 ° C. When the polymerization conversion reaches 90%, a polymerization terminator is added to terminate the reaction.

At this time, when the pH is 9 to 10.5 and distilled under reduced pressure so that the solid content becomes 40.5%, latex having excellent chemical and mechanical stability is produced.

The second step is the same condition as in Example 1.

Comparative Example 2 shows the monomer composition and the dosage ratio of the styrene-butadiene copolymer latex prepared by a typical low temperature emulsion polymerization reaction.

Comparative Example 2.

First step.

The following components were polymerized in an appropriate ion exchanged water at a reaction temperature of 4 ° C. in a stainless pressure reactor.

140.0 parts by weight of ion-exchanged water

4.75 parts by weight of potassium patitate

Tasher dodecyl mercaptan 0.5 parts by weight

Butadiene 71.0 parts by weight

Styrene 29.0 parts by weight

Potassium phosphate tri-woven

Tamorene 0.5 parts by weight

0.025 part by weight of para-methane hydroperoxide

The polymerization mixtures are heated to 7 ° C. and then polymerized. When the polymerization conversion reaches 60%, a polymerization terminator is added to terminate the reaction. At this time, the pH is 9 ~ 10.5 and distilled under reduced pressure to concentrate the solid content to 40.5% to produce a latex having excellent mechanical and chemical stability.

The second step is the same condition as in Example 1.

The physical property comparison of Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2 is shown in Table 2 below.

Property comparison table

TABLE 2

※ This test was conducted according to ASTM D 2138 test method.

Claims (2)

Rubber product reinforcement synthetic rubber adhesive Styrene-butadiene copolymer Latex production method, using a condensation reaction of formaldehyde and acrylamide as a crosslinking agent and a rubber product reinforcement synthesis consisting of high temperature emulsion polymerization reaction at a temperature of 60 ~ 80 ℃ Method for producing styrene butadiene copolymer latex for textile adhesives. The monomer according to claim 1, wherein the monomer is 50 to 90 parts by weight of butadiene and 10 to 40 parts by weight of styrene, 1.0 to 5.0 parts by weight of condensation reaction of formaldehyde and acrylamide and 2.0 to 5.0 parts by weight of potassium rosinate, 0.1 to 1.0 weight Negative tertiary dodecyl mercaptan, 0.1 to 1.0 parts by weight of tamolene, .1 to 1.0 parts by weight of sodium bisulfate, 0.1 to 2.0 parts by weight of phosphonic acid and 1.0 to 2.0 parts by weight of sodium hydroxide were added at a reaction of 60 to 80 ° C. After reaction at temperature, 0.1 to 1.0 parts by weight of potassium rosinate is added at a polymerization conversion rate of 60 to 80%, and a polymerization terminator is added at a polymerization conversion rate of 70 to 100% to terminate the reaction. Method for producing copolymer latex.