In Re Switzer

O’CONNELL, Associate Judge.

This is an appeal from the decision of the Board of Appeals of the United States Patent Office affirming the action of the Primary Examiner in rejecting claims 24 and 25 in appellants’ application for a patent for “certain new and useful improvements in Preserving Caustic Soda from Contamination.”

The claims in issue read as follows:

“24. A coating composition adapted to be applied to metal surfaces for service in. the presence of caustic soda which comprises a relatively small proportion of carbon black, a relatively large proportion of polystyrene having a molecular…