Dupont Canada Inc.

Erica M Besso

Peter A Sipos

A release sheet, comprising poly-4-methylpentene-1 film containing a copper salt of an alkanoic acid and at least one of an alkali metal halide and an alkaline earth metal halide, is disclosed. Such film is useful as a release sheet in the manufacture of printed circuit boards.

Polymethylpentene release sheet method of use

A process and nylon release sheet for manufacturing printed circuit boards from epoxy prepregs is disclosed. In such process layers of the prepregs are separated from one another by a release sheet. The release sheet comprises an aliphatic or aromatic nylon or nylon copolymer which is a condensation product of a dicarboxylic acid and a diamine. The nylon film contains a heat stabilizer and an inorganic particulate antiblock additive, e.g. diatomaceous earth, glass beads, amorphous silica, talc, mica and molybdenum disulphide. The nylon may be toughened by the addition of a phosphorus-containing catalyst or an epoxide.

Release sheet for printed circuit board manufacture

High temperature release sheet for printed circuit boards

A process for producing a polyamide with a relative viscosity of at least 100 is disclosed. The process comprises adding a catalyst selected from the group consisting of ortho-phosphoric acid, meta-phosphoric acid, alkali-metal hypophosphite and phenylphosphinic acid to the polyamide, which has a relative viscosity of from 30 to 70, mixing the catalyst and polyamide at a temperature above the melting temperature of the polyamide under reduced pressure and for a time sufficient to increase the relative viscosity of the polyamide to at least 100, and extruding the resulting polyamide into shaped form and quenching said polyamide. The catalyst is present in amounts of at least 0.01 wt. % and increases in relative viscosity may develop in times as short as about one minute.

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Manotick, Canada

Erica M Besso