Stamicarbon B.v.

Johannes A Brouwers

Edmond H Bour

Jean M Warnier

A new type of poly-2-pyrrolidone suitable for melt spinning and a process for its preparation. The new poly-2-pyrrolidone is characterized in that the polymer in the virgin state has a relative viscosity (1 gram of polymer in 100 ml of 96% sulphuric acid at 20.degree. C.) of between 2.2 and 7.0, shows a weight loss of less than 5% by weight when heated from 20.degree. C. to the onset temperature of thermal degradation at a rate 4.degree. C. per minute, the ratio between the relative viscosities after and before melt spinning ranges between 0.50:1 and 0.95:1, and the relative viscosity after melt spinning is at least 1.90. The new poly-2-pyrrolidone is prepared by polymerization of 2-pyrrolidone in the presence of an anionic catalyst and an accelerator wherein N-(2-caprolactim)-caprolactam is used as the accelerator in an amount of between 0.05 and 5.0 mole percent relative to the monomer, and the polymerization is carried out at a temperature of between about 25.degree. and 70.degree. C. until a relative viscosity of at least 2.2 is obtained.

Preparation of poly-2-pyrrolidone with N-(2-caprolactim)-caprolactam

An improved, consistent quality anionic catalyst for polymerizing pyrrolidone, optionally mixed with up to 25% of another copolymerizable lactam, is disclosed in which an alkali metal pyrrolidonate, prepared by reacting an alkali metal hydroxide or alkoxide with a molar excess of pyrrolidone, is heated for at least 5 hours at 100.degree.-175.degree. C. in the absence of water and air. Reproduceable results are obtained when the catalyst so heated is used to polymerize pyrrolidone.

Method for polymerizing pyrrolidone with preheating of catalyst solution

Polypyrrolidone polymers and copolymers are obtained by polymerizing 2-pyrrolidone, optionally with another lactam, in the presence of a catalyst and accelerator, first in the mass until at least 10% of the monomer is converted but the reaction product is still capable of suspension, then completing the desired degree of polymerization by suspending the reaction mixture in an inert liquid dispersion agent that does not dissolve the desired polymer. Relatively high molecular weight polymers are prepared in a short amount of time using this two-stage procedure.

Growing community of inventors

Echt, Netherlands

Johannes A Brouwers