Low-nitrile non-crosslinked powdered butadiene-acrylonitrile rubber and preparation method thereof

Abstract

The invention discloses a preparation method of low-nitrile non-crosslinked powdered butadiene-acrylonitrile rubber. The preparation method comprises the following steps of firstly, by taking butadiene and acrylonitrile as monomers, performing emulsion polymerization to synthesize butadiene-acrylonitrile latex, then performing condensation on the butadiene-acrylonitrile latex to prepare powder, and performing centrifugal dewatering and drying to obtain the low-nitrile non-crosslinked powdered butadiene-acrylonitrile rubber. In the stage of synthesizing the butadiene-acrylonitrile latex, the butadiene-acrylonitrile latex is prepared from the following components in parts by weight: 5-10 parts of acrylonitrile and 80-85 parts of butadiene by taking a compound, prepared from any one of ammonium persulfate, potassium peroxodisulfate and diisopropylbenzene hydroperoxide, sodium formaldehydesulfoxylate dihydrate, ferrous sulfate and EDTA disodium with the weight ratio of 1 to 0.5 to 0.25 to0.1 as an initiator. The preparation method has the advantages that the production technology is simple and liable to operate; polymerization conversion rate is improved, so that investment cost of the butadiene and acrylonitrile monomer recovery device is reduced; distribution of the acrylonitrile structural unit is more uniform; increase of polymerization reaction conversion rate at a lower temperature is facilitated; and the problem that the non-crosslinked butadiene-acrylonitrile latex with low nitrile content is difficult to prepare into powder is solved.

Description

technical field [0001] The invention relates to the technical field of powdered nitrile rubber, in particular to a low-nitrile non-crosslinked powdered nitrile rubber and a preparation method thereof. Background technique [0002] Powdered nitrile rubber is a polymer rubber emulsion synthesized by emulsion polymerization of butadiene, acrylonitrile and additives, and then powdered rubber is obtained through coagulation, powdering and drying. [0003] Powdered nitrile rubber has the advantages of small particle size, good dispersion when blended with other resins, and can be directly processed by plastic molding technology, which is conducive to the realization of continuous and automatic processing. At present, powdered nitrile rubber can be divided into non-cross-linked type (gel content<1%), micro-cross-linked type (gel content 5-30%) and cross-linked type (gel content 75-95%) according to the type of cross-linking. %) three types, and their uses are also different, am...

AI Technical Summary

Problems solved by technology

The low-nitrile non-crosslinked powdered nitrile rubber has not yet been produced, mainly because the polymerization reaction is usually carried out under low temperature conditions, the conversion rate is generally 70%, and there are still a large amount of monomers to be recovered, which requires large investment and high safety risks. In addition, low nitrile content latex is difficult to form powder particles due to its good toughness and high viscosity.