A kind of preparation method of high molecular weight fluorosilicone raw rubber

Abstract

The invention relates to a preparation method for high molecular weight fluorosilicone raw rubber. The method comprises the following steps of enabling NaOH powder to react with divinyltetramethyldisiloxane to prepare a catalyst, adding D3F and tetravinyl tetramethyl cyelo tetrasiloxane into a reactor for dehydration, adding the catalyst, raising the temperature, introducing nitrogen, and performing polymerization reaction at 60 to 160 DEG C for 0.25 to 7 hours while stirring, performing neutralization on raw rubber by using a neutralizing agent, and performing low-boiling residue removal operation to remove small molecular substances in the raw rubber to obtain the high molecular weight fluorosilicone raw rubber. According to the preparation method, sodium silanolate is used as the catalyst, and has the effects of both the catalyst and an end-capping reagent. Compared with the direct addition manner of the end-capping reagent divinyltetramethyldisiloxane, the preparation method disclosed by the invention has the advantages that the problem of incomplete reaction caused by different reaction rates is solved, the yield is increased, and the volatile matters are reduced; the prepared fluorosilicone raw rubber can be widely applied to the fields of aerospace, petrochemical industry, automobiles, artificial organs and the like.

Description

technical field [0001] The invention relates to a preparation method of high molecular weight fluorosilicone raw rubber, in particular to a preparation method of high temperature stable fluorosilicone raw rubber suitable for the fields of automobile, aerospace, machinery, petrochemical industry and the like. Background technique [0002] Fluorosilicone raw rubber is a high molecular polymer whose main chain is siloxane structure and side chains are fluorine-containing alkyl, methyl and vinyl groups. Fluorosilicone raw rubber is used as the main raw material, and reinforcing agents and structure control agents are added. , heat-resistant additives, vulcanizing agents and other additives can be mixed and processed to obtain fluorosilicone rubber. Fluorosilicone rubber combines the advantages of high and low temperature resistance of silicone rubber and oil and solvent resistance of fluororubber, and can be widely used in automobiles. , aerospace, petrochemical and other fields...

AI Technical Summary

Problems solved by technology

[0006] The synthesis of raw fluorosilicone rubber mostly adopts the bulk polymerization process, because D 3 F has high reactivity, the polymerization reaction will increase the viscosity of the system in a short period of time, and the polymerization process has the problem of difficult mass and heat transfer, resulting in difficult control of the molecular weight of raw rubber, wide molecular weight distribution, and low vinyl content. And other problems seriously affect the processing performance of fluorosilicone rubber and the performance of vulcanized products

[0007] Chinese patent document CN1844198A (application number: 200610035304.7) discloses a polymerization method of fluorosilicone raw rubber. This method uses a polymerization kettle with a screw type agitator to dehydrate the raw rubber polymerization in different reactors. , Polymerization, devolatilization, cooling, this method is cumbersome, and it cannot overcome the problems of uniform mixing and mass transfer and heat transfer of high-viscosity materials, and the neutralizer cannot be used to neutralize the catalyst during polymerization, so that the performance of raw rubber is affected. impact, the stability between batches is not guaranteed

[0008] Although the existing technology has partially solved the problems of mass transfer, heat transfer and quality instability in the polymerization process of fluorosilicone raw rubber, there are still no effective measures for the problems of uneven distribution of vinyl groups in the main chain of fluorosilicone raw rubber and wide molecular weight distribution.

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