SU1766931A1 - Method of chloroprene-acrylate latex preparation - Google Patents

Description

one

(21) 4886810/05 (22) 08.16.90 (46) 10/07/92. Bul №37

(71) All-Union Scientific Research and Design Institute of Polymer Products of the Scientific and Production Association Nairit

(72) A.V. Gevork, N.K. Calantar, E.S.Egien, L.Sh.Avanes, N.A.Gevork, M.E.O.All, N., M. K.Shush n, G.T. Martiros n, V.F.Borovskiy and R.R.Sarkis n

(56) USSR Copyright Certificate No. 495909, yu ,. C 08 F 236/18, 1962.

(54) METHOD FOR PRODUCING CHLOROPRENE-ACRYLATE LATEX

(57) Use: synthetic rubber industry, specifically the production of synthetic latex. SUMMARY OF THE INVENTION: upon receipt of latex, use

Monomeric mixture of the following composition, wt.h .: chloroprene 66-81; (meth) acrylic acid ester 15-30; (meth) acrylic acid 1-4. Conventional additives are used in the formulation, diisopropylxanthogen disulfide in the amount of 0.7-1.0 wt.h is used as a molecular weight regulator, calculated on the basis of 100 wt.h. comonomers. The process uses a three-stage temperature rise: before the conversion is 25–30% T, 20–25 ° C, then the temperature is raised to 40–45 ° C and maintained until the conversion is 60–70%, after it is raised to 55–60 ° C and carried out process to almost complete conversion of monomers. The obtained latex is stabilized and (tio) urea is additionally introduced in the amount of 1.5-2.0 wt.h. per 100 wt.h, comonomers. 3 tabl

with

The invention relates to the preparation of chloroprene-acrylate latexes intended for use as film-forming, binder and impregnating compositions.

As a prototype, a method for producing chloroprene-acrylate latex, the ratio of comonomers in which corresponds to 70:30, called MX-30, was chosen. Dispersion is widely used in the production of natural leather as a finishing material, as well as in the paint industry, construction equipment. The process of copolymerization of chloroprene is carried out at 40 ±, using sodium pentadecyl sulfonate (emulsifier E-30) as an emulsifier. Further, at deep degrees of monomer conversion (60-70% and higher), the temperature is maintained in the range of 55-60 ° C until the comonomers are almost completely converted to polymer.

A significant disadvantage of the chloroprene-acrylate copolymer latex obtained by the aforementioned method is the low physicomechanical properties of latex films: the tensile strength at break is no more than 8.0-8.5 MPa with a relative elongation of 600%, their thermal stability and water resistance are insufficient, as well as low adhesion properties that

The purpose of the invention is to increase the water resistance, heat resistance, adhesive characteristics, as well as the improvement of the physic

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mechanical properties of films based on chloroprene-acrylate latexes.

This goal is achieved by the fact that in the method of producing chloroprene-acrylate latex by aqueous emulsion copolymerization of chloroprene with an acrylic comonomer in the presence of a radical initiator, emulsifier and stabilizers, the process is carried out with the introduction of the third comonomer of (meth) acrylic acid in the amount of 1.0-4.0 ma.ch. by 1007 hp a comonomer mixture and molecular weight regulator diisopropylxane -trgene disulphide (diproxide) in an amount of 0.7-1.0 May, hours, carry out the depolymerization process by a three-stage temperature regime: at low degrees of comonomer conversion (25-30%) at a temperature of 20-25 ° C, at moderate degrees of conversion of comonomers at 40- 45 ° C and further at deep degrees of conversion of monomers (60-70% and above), the temperature is maintained in the range of 55-60 ° C until the almost complete conversion of comonomers into the polymer with the subsequent introduction into the finished latex (after its stabilization) (thio) urea in the amount of 1.5-2.0 wt.h.

The composition of the aqueous emulsion copolymerization mixture of chloroprene, wt.h .:

Chloroprene 81-66

Esters of (meth) acrylic acid15-30

(Meth) acrylic acid 1-4 Sodium alkylsulfonate (emulsifier E-30) 3.5-4.0

Ethoxylated alkylphenol (emulsifier OP-10) 0.8-1.2 Potassium persulphate 0.3-0.4 Diiso-Nylpropyl xanthogen disulfimd (diproxid) 0.7-1.0 Water 140-160 The method is carried out as follows .

1500 g of water are poured into the reactor for the preparation of the aqueous phase, then 40 g of emulsifier E-30 and 10 g of emulsifier OP-10 are added and using a stirrer, stirring is performed for 5-7 minutes (at 12-15 ° C) until complete dissolving emulsifiers.

Comonomers are poured into the reactor for the preparation of the hydrocarbon phase: 810 g of chloroprene, 150 g of methyl methacrylate and 40 g of methacrylic acid, 8 g of molecular weight regulator — diproxide, and by mixing for 5–8 min, complete dissolution of the hydrocarbon ingredients

phases. The temperature in the system is maintained within 15-18 ° C.

The hydrocarbon phase is drained into the reactor with the aqueous phase and produced

emulsification of the phases with vigorous stirring for 5-8 min. Then, the finished emulsion is poured into a polymerizer with simultaneous feeding of an initiator — potassium persulphate, the total content of which is 4 g (the initiator can be introduced in parts, as needed).

The process of copolymerization of chloroprene is carried out according to the following temperature regime: up to a conversion depth of 25-30% at 20-25 ° C, with average conversion values of 30-60% at a polymerization temperature of 40-45 ° C and after reaching a conversion of 60% and more polymerization

carried out at 55-60 ° C.

All other examples according to the invention were carried out according to a similar technology with different quantitative content of ingredients of the aqueous emulsion copolymerization system. The formulation of the mixture in examples 1-12 is shown in the table.

At the end of the chloroprene copolymerization process, the pH of the finished latex is adjusted to a value of 6-8 using 5-10% NaOH or KOH or 40-50% solution of triethanolamine. Latex is stabilized with an aqueous dispersion of stabilizer NG-22-46 (2.2 -methylene bis-4-methyl6-tert-butylphenol) or P-23 (2,4,6-tri-tert-butylphenol) at a rate of 1.5-2.0 mash. on 100

ma.ch. polymer In the finished latex is introduced

(thio) urea in the amount of 1.5-2.0 ma.ch.

Specific examples characterizing the proposed method for producing chloroprenacrylate latexes are given in Table. 1. Data on the temperature conditions of the process of chloroprene copolymerization at various

The stages (conversions) of monomer conversion for the considered examples are presented in Table. 2

Table 3 shows the colloid-chemical characteristics of the copolymer latexes obtained, their adhesion characteristics, the physicomechanical properties of free films based on them, as well as the water resistance and heat resistance (the induction period of NSP splitting,

For comparison, the properties of the prototype are summarized - dispersion MX-30 and base object - nairit L-MMA-M (a copolymer of chloroprene with methyl methacrylate and methacrylic acid with a comonomer ratio of 81: 15: 4, respectively

two-stage copolymerization method).

As evidenced by the table. 3, the samples of chloroprene-erylate latex obtained by this method are characterized by a significantly improved complex of properties compared with the prototype, which makes it possible to recommend the developed new type of chloroprene-; acrylate latex in addition to being used as a film-forming and impregnating agent in light industry (natural and artificial leather production technologies) as the basis of a binder and adhesive in construction equipment and other areas of national economy.

Claims (1)

The invention The method for producing chloroprene-acrylate latex by water-emulsion copolymerization of chloroprene with acrylic comonomer in the presence of a radical initiator, emulsifiers, molecular weight regulator with subsequent stabilization Chloroprene acrylate latex formulation 20 thirty 15 thirty M 1.5 3.0 k - test cases. latex, characterized in that, in order to improve water and heat resistance, physicomechanical and adhesive properties of latex-based films, (meth) acrylic acid ester is used as an acrylic co monomer; the process is carried out in the presence of (meth) acrylic acid; composition of the monomer charge, ma.ch .: chloroprene-66-81; ether (meth) acrylic acid-15-30; (meth) acrylic acid - 1-4; 0.7-1.0 parts by weight are used as molecular weight regulators. diisopropyl-santogendisulfida calculated per 100 wt.h. comonomers, while before the monomers are converted, 25-30% copolymerization is carried out at 20-25CC, then copolymerization is carried out up to 60-70% when the temperature rises to 40-45 ° C, and until the monomers are fully converted, the process is carried out at 55-60 C followed by separation after stabilization of latex 1.5-2.0 wt.h. (thio) urea per 100 mach. monomers. Table 1 25 25 15 15 thirty thirty 0.7 f, 3 4.0 1.5 Colloid-chemical properties of chloroprene-acrylate latex and physical and mechanical properties of free films based on them table 2 Table 3