In re Lewis

Worley, Chief Jvdge.

The issue here is whether the Board of Appeals erred in affirming the examiner’s rejection under 35 USC 103 of claims 1-3 in appellant’s patent application1 for “Cellular Polypropylene.”

*745Tlie claimed invention relates to a cross-linked stereo-regular polypropylene foam having a uniform cell structure with at least 70% of the cells being closed (not interconnected), and having a density of less than 10 lbs./cu. ft. The low density foam can be produced by heating a blend of stereoregular polypropylene, blowing agent and a poly(sulfonazide) cross-linking agent, a method held…