Impact resistant vinyl ester resin and process for making same

Abstract

Vinyl ester resins with improved impact resistance and other benefits and advantages may be obtained by a process modification wherein up to 20 percent of the unsaturated monocarboxylic acid, which is reacted with a polyepoxide, is replaced by an equivalent amount of a liquid carboxy terminated polydiene rubber capable of reacting with epoxy groups to form a chemically bound molecule. .Iadd.

What is claimed is: 
     
       1. A process for preparing a thermosettable resin having improved impact resistance in the thermoset state which comprises .[.simultaneously.]. reacting the epoxide moieties of a polyepoxide having an average of more than one epoxide group per molecule with the acid moieties of an unsaturated monocarboxylic acid and a liquid carboxy terminated polydiene rubber wherein the combined acid equivalents of said unsaturated acid and said polydiene ranges from about 0.8 to 1.2 equivalents per epoxide equivalent and wherein at least about 80 percent of said acid equivalents comprises said unsaturated acid and the balance between 0.01 and 20 percent comprises said polydiene, provided that the polydiene rubber content is at least about 4 weight percent .Iadd.and wherein said resin is prepared by the simultaneous reaction of said polyepoxide, said polydiene rubber and said monocarboxylic acid or by the sequential reaction wherein said polyepoxide and said polydiene rubber are reacted followed by addition and reaction of said monocarboxylic acid with the product of that first reaction.Iaddend.. 
     
     
       2. The process of claim 1 wherein said polydiene rubber has a molecular weight of 2,000 to 20,000. 
     
     
       3. The process of claim 1 wherein said polydiene rubber molecular weight is 3,000 to 10,000. 
     
     
       4. The process of claim 1 wherein said polydiene rubber is a polymer of a conjugated diene monomer. 
     
     
       5. The process of claim 1 wherein said polydiene rubber is a copolymer of a conjugated diene and a copolymerizable vinyl monomer. 
     
     
       6. The process of claim 1 wherein said polydiene rubber is a copolymer of acrylonitrile and butadiene. 
     
     
       7. The process of claim 1 wherein said polyepoxide has an epoxide equivalent weight of 250 to 700. 
     
     
       8. The process of claim 1 further comprising the step of admixing the thermosettable resin with a copolymerizable monomer. 
     
     
       9. A thermosettable resin prepared by the process of claim 1. 
     
     
       10. A thermosettable resin prepared by the process of claim 2. 
     
     
       11. A thermosettable resin prepared by the process of claim 3. 
     
     
       12. A thermosettable resin prepared by the process of claim 4. 
     
     
       13. A thermosettable resin prepared by the process of claim 5. 
     
     
       14. A thermosettable resin prepared by the process of claim 6. 
     
     
       15. A thermosettable resin prepared by the process of claim 7. 
     
     
       16. A thermosettable resin prepared by the process of claim 8.