New Alfin Rubbers

Abstract

Molecular weight control for alfin catalyzed 1,3-diene polymers by 1,4-diene straight chain or cyclic hydrocarbons (and their derivatives) has been demonstrated. The microstructure of these moderated polymers is identical to the polymers obtained without molecular weight control. From the wide series of copolymers preparable with this improved polymerization method four were chosen for their evaluation after laboratory testing for processability, physicals, and economics. Copolymers of butadiene—isoprene (90/10 and 97/3) and butadiene—styrene (85/15 and 95/5) virgin or oil extended have been shown to be economically attractive and to give superior wear, traction, and adequate heat build up.

The Formation of Gel in Alfin-Plus Polymerization

“…For with alfin rubber, the prime problem appears to be quality more than the extremely high molecular weight that has so often been credited [6][7][8][9][10] as causing failures. An extremely high molecular weight within a minute has been a feature since the discovery of the catalyst, but only lately has good quality been attainable by giving attention to the better utilization of the surface (that is, more of the surface being used for polymerization and less for side reactions [3] and to the condition of the surface -freedom from propylene -where the extraordinary rapid chain growth is taking place.…”

Synthesis of a high‐trans 1,4‐butadiene/isoprene copolymers with supported titanium catalysts

“…As a solution to these problems with TPB, an abundant and low‐cost butadiene (Bd) resource can be used, and a new kind of trans synthetic rubber can be exploited for high‐performance tire stock; the copolymerization of Bd and isoprene (Ip) has received considerable attention. It has been demonstrated that this copolymerization is an effective way not only of reducing the crystallinity of the polymers greatly but also of obtaining copolymers with high‐trans configurations based on vanadium,12 anion,2, 13 and alfin14 catalyst systems. However, the commercialization of Bd–Ip copolymerization with these catalyst systems has not been carried out for some reason.…”