Perman & Green
Process for the production of void-free prepreg sheets
 A method is disclosed for the manufacture of void-free prepregs formed by the impregnation of a reinforcing cloth (e.g. glass fiber cloth) with a solution of a thermosetting resin (e.g. epoxy resin). In the method, the reinforcing cloth is first prewetted with a liquid medium containing a solvent for the resin which has a viscosity less than that of the solution of thermosetting resin. The prewetted cloth is impregnated with a solution of the resin and then heated to remove the solvent and cure the resin. The prepregs are used in the manufacture of printed circuit boards. 
International Business Machines Corp.
C H H C
C08J H05K H05K C08J
inventional additional additional additional
Ho M. Yaffa Neng H. Thomas C.
Tong Tomkiewicz Lu Clarke