Polymer/polyols having improved combustion resistance and intrinsic viscosity, methods of making same and polyurethanes prepared therefrom

A normally liquid, stable polymer/polyol composition formed by polymerizing in the presence of a free radical catalyst and in the essential absence of an alkyl mercaptan chain transfer agent, (1) from about 25 to about 60 weight percent of a mixture of acrylonitrile and an ethylenically unsaturated comonomer or comonomers in a weight ratio, respectively, of from about 45:55 to 25:75, dissolved or dispersed in (2) from about 40 to about 75 weight percent of a polyol mixture comprising (a) a base polyol having a hydroxyl number of less than about 150 and (b) a stabilizer precursor having retained unsaturation of at least about 0.05 milliequivalent per gram which is at least 50 percent of the added unsaturation and said stabilizer precursor is present in an amount sufficient to assist the dispersion stability of the resulting polymer/polyol, the polymer of said polymer/polyol being characterized by a crosslinking coefficient of less than about 10 and an intrinsic viscosity of greater than 0.62.

A normally liquid, stable polymer/polyol composition formed by polymerizing in the presence of a free radical catalyst and in the essential absence of an alkyl mercaptan chain transfer agent, (1) from about 25 to about 60 weight percent of a mixture of acrylonitrile and an ethylenically unsaturated comonomer or comonomers in a weight ratio, respectively, of from about 45:55 to about 25:75, dissolved or dispersed in (2) from about 40 to 75 weight percent of a polyol mixture comprising (a) a base polyol having a hydroxyl number of less than about 150 and (b) a stabilizer precursor present in an amount sufficient to assist the dispersion stability of the resulting polymer/polyol, the polymer of said polymer/polyol being characterized by a crosslinking coefficient of less than about 5 and an intrinsic viscosity of at least about 0.62.

A normally liquid, stable polymer/polyol composition formed by polymerizing in the presence of a free radical catalyst and in the essential absence of an alkyl mercaptan chain transfer agnet, (1) from about 30 to about 60 weight percent of a mixture of acrylonitrile and an ethylenically unsaturated comonomer or comonomers in a weight ratio of from about 45:55 to about 25:75, dissolved or dispersed in (2) from about 40 to about 70 weight percent of a polyol mixture comprising (a) a base polyol having a hydroxyl number of less than about 150 and (b) a stabilizer precursor present in an amount sufficient to assist the dispersion stability of the resulting polymer/polyol, the polymer of said polymer/polyol being characterized by a crosslinking coefficient of less than about 5 and an intrinsic viscosity of at least about 0.55.

The polymer/polyol composition of claim 37 wherein said base polyol is a poly (oxypropylene) polyol.

A normally liquid, stable polymer/polyol composition formed by polymerizing in the presence of a free radical catalyst and in the essential absence of an alkyl mercaptan chain transfer agent, (1) from about 25 to about 60 weight percent of a monomer mixture of styrene and a comonomer or comonomers in a weight ratio of from about 75:25 to about 100:0, dissolved or dispersed in (2) from about 40 to about 75 weight percent of a polyol mixture comprising (a) a base polyol having a hydroxyl number of less than about 150 and (b) a stabilizer precursor present in an amount sufficient to assist the dispersion stability of the resulting polymer/polyol, the polymer of said polymer/polyol being characterized by a crosslinking coefficient of less than about 55 and an intrinsic viscosity of at least about 0.30.

A process for producing a normally liquid, stable polymer/polyol capable of conversion to a polyurethane which comprises:

• (a) providing a base polyol having a hydroxyl number of less than about 150, (b) dissolving or dispersing from about 25 to about 60 weight percent of an ethylenically unsaturated monomer or monomers in from about 40 to about 75 weight percent of said base polyol, and (c) polymerizing in the presence of a free radical catalyst and a polymer control agent having at most minimal chain transfer activity, said polymer control agent being present in an amount sufficient to provide the polymer/polyol with a product viscosity which is lower than if said polymer/polyol was prepared in the absence of said polymer control agent while retaining an intrinsic viscosity of at least 0.30.

The process for producing the normally liquid, stable polymer/polyol composition of claim 62 wherein the crosslinking coefficient is less than about 20.

A normally liquid, stable polymer/polyol composition, capable of conversion to a polyurethane, formed by polymerizing in the presence of a free radical catalyst and a polymer control agent having at most minimal chain transfer activity, (1) from about 25 to about 60 weight percent of an ethylenically unsaturated monomer or monomers, dissolved or dispersed in (2) from about 40 to about 75 weight percent of a polyol having a hydroxyl number of less than about 150, the polymer/polyol having a product viscosity which is lower than if said polymer/polyol had been prepared in the absence of said polymer control agent and an intrinsic viscosity of at least 0.30.

A process for reducing the viscosity of a polymer/polyol, capable of conversion to a polyurethane, which comprises:

• (a) providing a normally liquid, stable polymer/polyol composition formed by polymerizing in the presence of a free radical catalyst (1) from about 25 to about 60 weight percent of an ethylenically unsaturated monomer or monomers, dissolved or dispersed in (2) from about 40 to about 75 weight percent of a base polyol having a hydroxyl number of less than about 150, said polymer being present in the form of particles and characterized by an intrinsic viscosity of at least 0.30, and said polymer/polyol composition having a viscosity above its indigenous viscosity and (b) treating the polymer/polyol to reduce the viscosity of the polymer/polyol composition to essentially its indigenous viscosity.