Tough plastics based on castor oil elastomer-reinforced vinyl polymers

Claim 1

A method for producing a formed castor oil elastomeric-reinforced polyvinyl plastic product which comprises heating a mixture consisting of (a) 5-15% by weight of a castor oil elastomer prepolymer and catalyst therefor said prepolymer selected from the group consisting of a caster oil-multibasic acid polyester and a multifunctional isocyanate and copolymers thereof, and (b) 95-85% of a vinyl, plastic forming monomer selected from the group consisting of methyl methacrylate and homologues, styrene and derivatives and vinyl chloride and homologues, together with a multivinyl crosslinking monomer therefor to a temperature sufficiently high to initiate polymerization of said vinyl but not sufficiently high to polymerize said castor oil elastomer prepolymer, stirring said mixture at said temperature until said vinyl is polymerized sufficiently to form a separate phase and to become a continuous separate phase, but before said composition begins to gel due to crosslinking of said vinyl, then forming the reacting mixture to final product shape and holding said formed product at said elevated temperature for at least an hour, after which it is heated to a second elevated temperature sufficiently high to completely polymerize said castor oil elastomer prepolymer and holding said product at said temperature until said reaction is complete.

Claim 2

A method for producing a formed castor oil elastomeric-reinforced polyvinyl plastic product which comprises heating a mixture consisting of (a) 5-15% by weight of a castor oil elastomer prepolymer and catalyst therefor said prepolymer selected from the group consisting of a caster oil-multibasic acid polyester and a multifunctional isocyanate and copolymers thereof, and (b) 95-85% of a vinyl, plastic forming monomer selected from the group consisting of methyl methacrylate and homologues, styrene and derivatives and vinyl chloride and homologues, together with a multivinyl crosslinking monomer therefor to a temperature sufficiently high to initiate polymerization of said vinyl but not sufficiently high to polymerize said castor oil elastomer prepolymer, stirring said mixture at said temperature until said vinyl is polymerized sufficiently to form a separate phase and to become a continuous separate phase, but before said composition begins to gel due to crosslinking of said vinyl, then forming the reacting mixture to final product shape and holding said formed product at said elevated temperature for at least an hour, after which it is heated to a second elevated temperature sufficiently high to completely polymerize said castor oil elastomer prepolymer and holding said product at said temperature until said reaction is complete.

Claim 11

The method of any of claims 1, 2, 4, 5, 6, 8, wherein said castor oil elastomer prepolymer in said mixture is partially prepolymerized before combination with said vinyl monomer.

Claim 12

The method of any of claims 1, 2, 4, 5, 6, 8, wherein said mixture is stirred at a first elevated temperature of 60°-90° C. for 110-140 hours prior to product forming, is thereafter held at said temperature for hours and is then finally cured at 180° C. for 12 hours.