W. R. Grace Co.

Coors Porcelain Company

Paul A Boduch

James E Stephan

Francis J Rendulic

Robert K Trasavage

John A Elverum

Printed circuit boards are made by imaging a liquid polymer which has been coated onto the board. The imaging is accomplished while the polymer is wet with the photo tool in a close air gap relationship with the coated board. The uncured polymer which remains liquid is removed after imaging so that the board can be processed by etch resist, plate resist, or solder mask techniques. The cured polymer is removed by stripping with an alkaline solution. The apparatus consists of single station or multi-station equipment to carry out the unit operations of maintaining the board in a set position, coating with a liquid polymer, placing a photo tool in registration with the circuit board blank and in close relationship with the coating, and imaging the liquid polymer via the photo tool to cause areas of the coating to solidify and other areas to remain liquid.

Method and apparatus for making printed circuit boards

A method for making cast precision epoxy resin bodies and an epoxy resin formulation for use therein, the epoxy resin formulation having Component A consisting essentially of from 40 to 70% by weight epoxy novolac polymer, from 30 to 50% by weight vinyl -3-cyclohexene diepoxide and from 0 to 20% by weight 3,4 epoxy cyclohexylmethyl -3,4-epoxy cyclohexane carboxylate and Component B consisting essentially of partially hydrolyzed aryl tetracarboxylic acid dianhydride, preferably partially hydrolyzed pyromellitic acid dianhydride. In the preferred embodiments a tertiary amine catalyst is also included. These components are mixed, just before use, in a ratio of from 20 to 50 parts by weight Component B to each 100 parts by weight Component A. To make the cast precision bodies such mixture is cast in a mold of the shape desired, allowed to cure to a solid body while in the mold, and thereafter heated to cause permanent expansion thereof at least sufficient to compensate for any shrinkage occurring during the casting and hardening thereof while in the mold.

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Lakewood, CO, United States of America

Paul A Boduch