Catalyzing system for isoprene polymerization and preparation and application method of catalyzing system

Abstract

The invention belongs to a catalyzing system for isoprene polymerization and preparation and an application method of the catalyzing system. The catalyzing system is composed of A) rare earth organic carboxylate compound, B) organic aluminum compound, C) activating agent, D) acrylate compound and E) carboxylic aromatic cyclic ester compound containing total carbon number of C7-C9 according to molar ratios that A:B=1:1-30, A:C=1:1-3, A:D=1:1-60, and A:E=1:5-50. The prepared catalyzing system forms pre-polymerized catalyst activity central body during ageing at 0-80 DEG C. The catalyzing system can be maintained for 180 days at the room temperature, the monomer conversion rate is higher than 98% in polymerization, the molecular weight distribution index of the synthesized poly-isoprene rubber is 1.6-2.8, cis-form 1,4 structural unit content is higher than 96%, and the Mooney viscosity satisfies that ML1+4100 DEG C =40-80.

Description

technical field [0001] The invention relates to a catalytic system for isoprene polymerization and its preparation and application method. Background technique [0002] Polyisoprene with high cis-1,4 structural unit content (cis-1,4 structural content>90%) can be synthesized by directional polymerization of isoprene under the action of titanium series, lithium series and rare earth catalysts. This material is particularly suitable for the manufacture of tires and other elastic materials. [0003] Compared with the polyisoprene rubber obtained by traditional titanium-based catalysis, the polyisoprene rubber obtained by rare earth catalysis has a high monomer conversion rate (conversion rate > 98%), regular molecular chain structure, cis-1 , 4 structure content > 95%, no gel, raw rubber appearance is close to colorless, residual catalyst does not need to be removed. It has better raw rubber strength, tear resistance, self-adhesiveness, abrasion resistance, flex crac...

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Problems solved by technology

Disclosed as CN1840552A is a kind of rare-earth catalyst system that is used for the polymerization of conjugated dienes, and its third component is chlorinated alkanes, and the fourth component is conjugated dienes and organic acid; In addition, the third component of catalyst disclosed in CN1347923A is chlorine Silane, the fourth component is conjugated diene, this type of rare earth catalyst is mostly a heterogeneous or semi-homogeneous catalytic system, the stability of the catalyst is poor, and there may be multiple active centers, and the catalytic polymerization process is difficult to control , so the molecular weight and distribution of the polymer are too wide, and the dynamic viscosity of the polymerization system is very large, which brings difficulties to the production process of heat transfer, transportation, glue spraying, etc., limits the increase of the monomer concentration, and reduces the production capacity and efficiency

At the same time, the above-mentioned catalytic system is used in the polymerization process of isoprene for a long initiation time (usually 2-6min for isoprene initiation time), long polymerization reaction time (usually 3.5h for isoprene polymerization time), isoprene Low conversion of isoprene (typically less than 92% conversion of isoprene)

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