Abstract: An insulating board has a polymeric reinforcement layer of fibrous material with a predetermined dielectric constant. A polymer is impregnated into said reinforcement layer and has a dielectric constant which is close to that of the dielectric constant of said fibrous material and the insulating board exhibits isotropic properties. A preselected desired dielectric constant or loss tangent can be built into the board by selection of fillers to preselect the dielectric constant or loss tangent without detracting from desired mechanical properties of the board.
Type:
Grant
Filed:
August 17, 1978
Date of Patent:
December 23, 1980
Assignee:
Castall Incorporated
Inventors:
Ralph C. Pratt, Robert Davis, Charles P. Howland