SU927800A1 - Process for isolating rubber from butadiene-styrene latex - Google Patents

Description

The invention relates to the technology of separation of rubbers from synthetic latexes, in particular, buta-, di-styrene latex, and can be used in the petrochemical industry.

A known method for isolating rubber from synthetic latexes stabilized by carboxylic acid soaps is by introducing sodium chloride followed by treatment with sulfuric acid 1.

The disadvantages of this method are the large consumption of wash water that pollutes the environment and requires significant costs for the treatment plant. In addition, when using this coagulant, small rubber crumbs are formed, which leads to loss of rubber when it is separated from the serum and is reflected in the physical and mechanical properties of rubber.

The closest to the invention in its technical nature is a method for isolating rubber from styrene-butadiene latex stabilized by sodium soaps of fatty acids of fraction C, o-C, g, by introducing an additive that facilitates coagulation, followed by treatment with sulfuric acid. tdrolizirovanny polyacrylonitrile 2.

The disadvantage of this method is that the use of hydrolyzed polyacrylonitrile does not improve the physico-mechanical properties of rubbers and does not reduce the consumption of sulfuric acid for coagulation (acid consumption 30.5 kg per ton of rubber).

The purpose of the invention is to improve the physico-mechanical properties of rubber and reduce the consumption of sulfuric acid.

15

It is achieved that, according to the method for isolating rubber from styrene-butadiene latex stabilized with sodium soaps of the fatty acid fraction

20 Co, by the addition of a coagulation aid, followed by treatment with sulfuric acid, as a coagulation aid, 3-4 wt.h. on

25 100 ma.h. rubber copolymer of acrylic acid with 2-methyl-5-vinylpyridine.

Example 1. Kyuml butadiene styrene latex - product

30 emulsion copolymerization of butadiene and styrene in the presence of an emulsifier — sodium salts of fatty acids of fraction С, 0 С j (СКС-ЗОП), filled with neozon D 0.5%, with a dry residue content of 42% at 35-40 1% aqueous solution of acrylic acid copolymer with 80 mol.% 2-methyl-5-vinylpyridine (AK: 2M5VP). After stirring for 5 minutes, 3.6 ml of a 1% aqueous solution of sulfuric acid are added to the mixture. At pH 4/6, a complete coagulation of the latex is observed. The rubber is in the form of coarse crumbs. The rubber is separated from the serum, washed with distilled water and dried at 8O-9O c. Examples 2-9. Coagulation is carried out at different ratios of the Supplement, facilitating coagulation and sulfuric acid. The results are shown in Table. 1. As can be seen from the data table. 1, when using a copolymer of acrylic acid with 2-methyl-5-vinylpyridine in the amount of 3-4 wt.h. and sulfuric acid in the amount of 0.8-0.9 wt.h. on 100 ma.ch. rubber efficiency is maximum. Rubber compounds that are subjected to vulcanization are prepared from the isolated rubber. Physico-mechanical properties of the samples obtained are given in table. 2. Here, for comparison, the results of the study of indicators of the control sample (by a known method) are presented. As can be seen from the table. 2, the use of a solution of a copolymer of acrylic acid with 2-methyl-5-vinylpyridine as a coagulating additive leads to an improvement in the physical and mechanical properties of rubbers: the tensile strength increases by 1.3 times, the specific volume resistance by 10 times; surface electrical resistance of 7 times; residual elongation is reduced by 1.5 times. In addition, the use of this copolymer also makes it possible to significantly reduce the amount of sulfuric acid per coagulation to 8 kg per ton of rubber and thereby reduce the discharge of chemically contaminated water to the sewage treatment plant (the copolymer remains in the rubber crumb). Table 1

3.0 4.0 3.6 3.5 3.5 3.5

Indicator

Tensile strength, to GC / cm 2 Relative elongation,% Residual elongation,%

Rebound elasticity,% Specific volume electrical resistance, cm Specific surface electrical resistance, cm

100 ,

Same i 1

98.8 96.7

table 2

--- t --- - ----- - - -.

Famous

Proposed facility

251

180

12

32

2.7-3

ten

one,

59278006

 the invention as an additive facilitating.

The method of separation of rubber from bu-100 mach. couchuca copolymer

tadienstyrene latex, stabil-acrylic acid with 2-methyl-5-vinylized sodium soap fat, pyridine.

acids of the fraction-C "by. Sources of information, the introduction of an additive that facilitates coagu-taking into account during the examination, with the subsequent processing of serum. 1. Kirpichnikov P.A. other. Khinoy ACID, distinguishing-micron to the technology of synthetic Kaus, in order to improve the chuk. L., Chem. 1970, 398-399, physicomechanical properties of rubber 2. USSR Author's Certificate and Reduction of Sulfuric Acid Consumption, 536193, grade C 08 C 1/15, 1975 (prototype)

coagulation, 3-4 math. used.

Claims (1)

Claim A method for isolating rubber from styrene-butadiene latex stabilized with sodium soaps of fatty acids of fraction C " _o ~ C", by ⁵ introducing an additive that facilitates coagulation, followed by treatment with sulfuric acid, characterized in that, in order to improve the physicomechanical properties of rubber θ and reducing the consumption of sulfuric acid, as an additive facilitating coagulation, apply 3-4 wt.h. per 100 parts by weight rubber of a copolymer of acrylic acid with 2-methyl-5-vinylpyridine.