Modified vinyl ester resin and pipe made therefrom

Claim 1

The method for forming centrifugally cast pipe comprising: inserting a sock of fibrous reinforcing material into the mold of a centrifugal casting machine; injecting into said mold a quantity of a first thermosetting resin, said quantity being sufficient to substantially encapsulate said reinforcing material, rotating said mold so as to distribute said injected first resin longitudinally of said mold throughout said reinforcing material to thereby form within said mold a cylindrical matrix of said first thermosetting resin and said fibrous reinforcing material, injecting into the bore of said cylindrical matrix of said first thermosetting resin and said fibrous reinforcing material a second thermosetting resin comprising an admixture of (1) a neat thermosetting resin formed by reacting an epoxy resin, a carboxyl terminated elastomer selected from the group consisting of carboxyl terminated homopolymers and copolymers of conjugated dienes and an unsaturated monocarboxylic acid, with approximately one chemical equivalent of epoxy being provided for each chemical equivalent of carboxyl provided by said elastomer and said acid combined and (2) an ethylenically unsaturated monomer, rotating said mold to distribute said second thermosetting resin longitudinally thereof to form an unreinforced inner liner for said pipe on the inner surface of said cylindrical matrix of said first thermosetting resin and said fibrous reinforcing material prior to the curing of said first thermosetting resin to thereby permit limited intermingling of said first and second thermosetting resins at their interface, and applying heat to said mold while said mold is rotating to cure said first and second resins and to cross-link said first and second resins at their intermingled interface to thereby form an unreinforced inner lining of said second thermosetting resin for said pipe.

Claim 2

The method for forming centrifugally cast pipe comprising: inserting a sock of fibrous reinforcing material into the mold of a centrifugal casting machine; injecting into said mold a quantity of a first thermosetting resin, said quantity being sufficient to substantially encapsulate said reinforcing material, rotating said mold so as to distribute said injected first resin longitudinally of said mold throughout said reinforcing material to thereby form within said mold a cylindrical matrix of said first thermosetting resin and said fibrous reinforcing material, injecting into the bore of said cylindrical matrix of said first thermosetting resin and said fibrous reinforcing material a second thermosetting resin comprising an admixture of (1) a neat thermosetting resin formed by reacting an epoxy resin, a carboxyl terminated elastomer selected from the group consisting of carboxyl terminated homopolymers and copolymers of conjugated dienes and an unsaturated monocarboxylic acid, with approximately one chemical equivalent of epoxy being provided for each chemical equivalent of carboxyl provided by said elastomer and said acid combined and (2) an ethylenically unsaturated monomer, rotating said mold to distribute said second thermosetting resin longitudinally thereof to form an unreinforced inner liner for said pipe on the inner surface of said cylindrical matrix of said first thermosetting resin and said fibrous reinforcing material prior to the curing of said first thermosetting resin to thereby permit limited intermingling of said first and second thermosetting resins at their interface, and applying heat to said mold while said mold is rotating to cure said first and second resins and to cross-link said first and second resins at their intermingled interface to thereby form an unreinforced inner lining of said second thermosetting resin for said pipe.