Patent EA-000986-B1 (EA)
Title: Thin isotropic film based on thermosetting resin
Inventor: GEBHARDT WILLIAM F
IPC: B29C59/02
Filed: 1996-06-07
Abstract: 1. An isotropic, thin thermosetting resin film, in particular dielectric, that shapes by stamping and compression molding and with respect thereto it can be molded without containing flow of the resin film on the edges of polymer film, wherein it forms a thermoset dielectric substrate, is sufficiently uniform in thickness to provide consistent and essentially uniform heat shaping capability across the whole of the film, has low flow over a broad temperature range so that it does not flow uncontrollably while undergoing cure conditions, and when placed under pressure, only the potions that are superimposed over a groove or cavity in the case of a female mold, or over a protuberance in the case of a male mold, will be caused to flow because of pressure imposed on the film; and gels or near-gels to meet commercial requirements, and the thickness is sufficient to accept the shape imposed by a shaping process. 2. The film of claim 1 wherein the film comprises a thermosetting resin that advances in molecular weight without forming a significant volatile byproduct and a flow control component. 3. The film of claim 1 wherein the film possesses an uniform areal thickness ranging from about 0.0254 mm to about 6.35 mm with minimum and maximum thicknesses not exceeding the deviation factor set forth in Table A   TABLE A Range in mm Deviation Factor from 0,0254 to 0,127 mm +- 0,0254 mm from o,127 to 0,254 mm +- 0,0508 mm from 0,254 to 6,35 mm +- 20%   low flow at a broad temperature range; the ability to cure, gel, or near-gel, at temperatures from about 20 degree C to about 250 degree C, in less than about 7 days and more than 1 second; a low dielectric constant in the thermoset state. 4. The film of claim 2 wherein flow control component comprises, at least, one of the following components: at least one electronic grade filler; a thermoplastic resin that is soluble or partially soluble in the thermosetting resin; a polymer of elastomer type that provides discrete elastomer phases (second phase) in the thermosetting resin matrix; and a thixotrope. 5. The film of claim 1 wherein the film when cured is metal platable and adheres to a conductive metal film. 6. The film of claim 1 wherein the film adhesively bonds to metal foil and can be used to make a stamping surface or create a conductive pathway on a stamped and cured resin film. 7. The film of claim 1 wherein the film is shaped to contain grooves suitable for use in making a conductive pathway in a printed circuit board. 8. The film of claim 1 wherein the thermosetting resin is an epoxy resin. 9. The film of claim 1 wherein the thermosetting resin is from the group consisting of bismaleimide, phenolic, polyester, PMR-15 polyimide, cyanate ester, vinyl ester and acetylene terminated resins. 10. The film of claim 9 wherein the thermosetting resin is a mixture of an epoxy resin and a cyanate resin. 11. The film of claim 9 wherein the thermosetting resin is a vinyl ester resin. 12. The film of claim 4 wherein the flow control agent comprises a polymer of elastomer type. 13. The film of claim 4 wherein the flow control agent comprises a polyurethane. 14. The film of claim 13 wherein the flow control agent comprises a polyurethane containing uriedo bonded phenolic hydroxyl containing terminal groups. 15. The film of claim 1 wherein the resin contains in situ-expandable thermoplastic particles. 16. The film of claim 1 wherein the resin contains a low profile additive. 17. A thin, isotropic, thermoset resin film made by curing the essentially nonconductive, isotropic, thin thermosetting resin film of claim 1 to 16. 18. The thin, isotropic, thermoset resin film made by curing the essentially nonconductive, isotropic, thin thermosetting resin film of claim 1 to 16 and containing a thin metal foil film adhesively bonded thereto. 19. The film of claim 18, wherein the thin metal foil is copper.