Oligomers and homopolymers of meta- or para-isopropenyl-.alpha.,.alpha.-dimethylbenzylisocyanate
AssigneeAmerican Cyanamid Company
InventorFrederic C. Schaefer
Life of this patent
Estimating the term…
Abstract
Aromatic solvent-soluble linear oligomers or homopolymers of meta- or para-isopropenyl-.alpha.,.alpha.-dimethylbenzylisocyanate characterized by high isocyanate content are disclosed. Such oligomers or homopolymers are made by catalytic solution polymerization of the monomer in methylene chloride and/or toluene solution at a temperature of from about -80.degree. C. to about -25.degree. C., followed by low-temperature neutralization of the polymerization catalyst.
Claims15
A method of forming oligomers or homopolymers of meta- or para-isopropenyl-.alpha.,.alpha.-dimethylbenzylisocyanate comprising:
- (a) solution polymerizing meta- or para-isopropenyl-.alpha.,.alpha.-dimethylbenzylisocyanate in a solvent selected from the group consisting of methylene chloride, toluene, and mixtures thereof, at a temperature of from about -80.degree. C. to about -25.degree. C. in the presence of a catalytically effective amount of a polymerization catalyst selected from the group consisting of:
- Bronsted acids and Lewis acids;
- and
- (b) neutralizing said polymerization catalyst at a temperature of from about -80.degree. C. to about 10.degree. C., thereby preventing substantial formation of isocyanic acid.
A process for forming homopolymers of meta- or para-isopropenyl-.alpha.,.alpha.-dimethylbenzylisocyanate, comprising:
- (a) passing a first stream comprising a methylene chloride solution of meta- or para-isopropenyl-.alpha.,.alpha.-dimethylbenzylisocyanateinto a first reaction zone;
- (b) concurrently with step (a), passing a second stream comprising a methylene chloride solution of a catalytically effective amount of stannic chloride into said first reaction zone to form therein with said first stream a reaction volume;
- (c) maintaining said reaction volume under mixing conditions in said first reaction zone at a temperature from about -80.degree. C. to about -25.degree. C. for a time sufficient to polymerize said meta- or para-isopropenyl-.alpha.,.alpha.-dimethylbenzylisocyanate therein to a predetermined extent;
- (d) passing a stream of the polymerized reaction volume from said first reaction zone to a second reaction zone;
- (e) concurrently with step (d) passing to said second reaction zone a third stream comprising a methylene chloride solution containing pyridine in sufficient concentration and at sufficient flow rate of said third stream to neutralize said stannic chloride by complexing of pyridine therewith;
- (f) discharging neutralized homopolymer-containing solution from said second reaction zone;
- and
- (g) recovering said homopolymer from said discharged homopolymer-containing solution.
Dependencies are inferred from the claim text.