Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1993-11-02
2001-01-09
Kuhns, Allan R. (Department: 1732)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S436000, C524S492000, C524S494000, C524S497000, C524S544000, C524S545000, C524S546000
Reexamination Certificate
active
06172139
ABSTRACT:
TECHNICAL FIELD
The present invention relates to particulate filled polymer matrix composite materials and methods of manufacturing same and more particularly to thin films of highly filled polymer matrix composite materials.
BACKGROUND OF THE INVENTION
Laminated electrical circuit substrates which include a conductive layer supported on a dielectric fluoropolymer matrix composite layer are known. Driven by the continuing trend toward increasing circuit density, very thin films, e.g. less than about 1.0 mil, of highly filled fluoropolymeric matrix composite substrate materials having a substantially uniform microstructure have become desirable as allowing further reduction in the size of electronic circuits. It is technically and economically difficult to make such materials by known methods.
Fluoropolymer and particulate filled fluoropolymer matrix composite films are made by known papermaking, skiving, casting, melt extrusion and paste extrusion and calendering processes.
Films produced by paper making processes required fiber reinforcement and are limited to thicknesses greater than about 2 mil.
It is very difficult to produce thin high quality highly filled fluoropolymer matrix films by skiving due to abrasion of the skiving blade by the filler particles and tearing of the film associated with the resistance of the filler particles to the skiving blade.
The filler loading of films made by known casting processes is limited to less than about 15 volume percent.
The high melt viscosity of neat fluoropolymers complicates the production of fluoropolymer films by melt extrusion. Polyvinylidene fluoride (PVF
2
) and polychlorotrifluoroethylene (PCTFE) are melt extrudable only within a narrow processing window. Polyvinylfluoride (PVF) film cannot be produced by welt extrusion due to thermal instability. Polytetrafluoroethylene (PTFE) cannot be melt extruded due to its extraordinarily high melt viscosity. Fluorocopolymers are known which provide lower melting temperature and lower melt viscosity at extrusion temperatures, e.g. copolymers of tetrafluoroethylene with hexafluoropropylene (FEP) or with ethylene, copolymers of CTFE with vinylidene fluoride or hexafluoropropylene.
The introduction of fillers further complicates the melt extrusion of fluoropolymers. In the presence of certain fillers, especially at high filler loading level, the melt processability of the melt extrudable fluoropolymers is rapidly degraded due to the increase in melt viscosity associated with the presence of the filler or with filler-catalyzed thermal degradation of the polymer matrix.
A method of making highly filled PTFE composite materials which exhibit excellent physical and electrical properties by paste extrusion and calendering is set forth in coassigned U.S. Pat. No. 4,849,284 to D. J. Arthur, J. C. Mosko, C. S. Jackson and G. R. Traut, entitled “ELECTRICAL SUBSTRATE MATERIAL”, the disclosure of which is incorporated herein by reference. However, it is technically difficult and economically extremely difficult to produce thin, i.e. less than 2 mils, highly filled, i.e. greater than about 40%, fluoropolymer matrix composite films by the paste extrusion and calendering process.
What is needed in the art is a method which overcomes the above noted deficiencies of known processing methods.
SUMMARY OF THE INVENTION
A particulate filled fluoropolymer matrix composite article is disclosed. The article includes a fluoropolymer matrix and up to about 95 vol. % filler particles distributed throughout the matrix, wherein said particles have a maximum equivalent spherical diameter of less than about 10 microns.
In an alternative embodiment, a particulate filled fluoropolymer matrix composite article comprises a fluoropolymer matrix and up to about 95 vol. % filler particles distributed throughout the matrix wherein none of the particles have a single linear dimension greater than about 10 microns.
In a preferred embodiment a particulate filled fluoropolymer matrix composite film comprises a nonfibrillated fluoropolymer matrix and greater than about 15 vol. percent filler particles distributed throughout the matrix. The film has a thickness less than about 2 mils and is free of visually evident pin holes or tears.
A porous fluoropolymer film comprising a nonfibrillated fluoropolymer matrix having a void volume of greater than about 15 vol. % and a thickness of less than about 2 mils is disclosed.
A method for making a particulate filled polymer matrix composite film is disclosed. The method comprises mixing the polymer with a dispersion of the particulate filler in a carrier liquid to provide a casting composition, wherein the casting composition includes relative amounts of polymer and filler effective to provide a film having greater than 15 volume percent filler casting a layer of the casting composition onto a substrate and consolidating the cast layer to form the particulate filled polymer matrix composite film.
A casting composition is also disclosed. The casting composition includes a mixture of liquid carrier, a polymeric matrix material, and particles of a filler material.
REFERENCES:
patent: 2852811 (1958-09-01), Petriello
patent: 2923651 (1960-02-01), Petriello
patent: 2961345 (1960-11-01), Petriello
patent: 3054716 (1962-09-01), Bergstein et al.
patent: 3054761 (1962-09-01), Moore et al.
patent: 3282725 (1966-11-01), Vanzalingo
patent: 3340222 (1967-09-01), Fang
patent: 3577508 (1971-05-01), Desaulniers
patent: 3679614 (1972-07-01), Shah et al.
patent: 3682859 (1972-08-01), Taylor et al.
patent: 3843570 (1974-10-01), Murayama
patent: 3928703 (1975-12-01), Cook
patent: 4049589 (1977-09-01), Sakane
patent: 4112037 (1978-09-01), Parker et al.
patent: 4134848 (1979-01-01), Adicoff et al.
patent: 4151154 (1979-04-01), Berger
patent: 4153661 (1979-05-01), Ree et al.
patent: 4183991 (1980-01-01), Smiley et al.
patent: 4196070 (1980-04-01), Chao et al.
patent: 4203848 (1980-05-01), Grandine, II
patent: 4211603 (1980-07-01), Reed
patent: 4307142 (1981-12-01), Blitstein et al.
patent: 4335180 (1982-06-01), Traut
patent: 4380521 (1983-04-01), Moreno et al.
patent: 4391930 (1983-07-01), Olson
patent: 4393119 (1983-07-01), Concannon
patent: 4409354 (1983-10-01), Namba et al.
patent: 4416941 (1983-11-01), Barsotti
patent: 4420449 (1983-12-01), Crocker et al.
patent: 4434116 (1984-02-01), Covitch
patent: 4469747 (1984-09-01), Sasaki et al.
patent: 4500603 (1985-02-01), Freundlich
patent: 4521596 (1985-06-01), Yoshimura et al.
patent: 4529774 (1985-07-01), Evans et al.
patent: 4555543 (1985-11-01), Effenberger et al.
patent: 4610918 (1986-09-01), Effenberger et al.
patent: 4634631 (1987-01-01), Gazit et al.
patent: 4680331 (1987-07-01), Suzuki et al.
patent: 4692287 (1987-09-01), Timmons
patent: 4772322 (1988-09-01), Bellis
patent: 4818619 (1989-04-01), Stepparola et al.
patent: 4824511 (1989-04-01), Hartman et al.
patent: 4847135 (1989-07-01), Braus et al.
patent: 4849284 (1989-07-01), Arthur et al.
patent: 4883716 (1989-11-01), Effenberger et al.
patent: 4888245 (1989-12-01), Nitzko
patent: 4895756 (1990-01-01), Suzuki
patent: 4915981 (1990-04-01), Traskos et al.
patent: 4915983 (1990-04-01), Lake et al.
patent: 4985296 (1991-01-01), Mortimer, Jr.
patent: 4987274 (1991-01-01), Miller et al.
patent: 4990544 (1991-02-01), Asaumi et al.
patent: 5055342 (1991-10-01), Markovich et al.
patent: 5126192 (1992-06-01), Chellis et al.
patent: 5198295 (1993-03-01), Arthur et al.
patent: 5312576 (1994-05-01), Swei et al.
patent: 5328756 (1994-07-01), Wright et al
patent: 5354611 (1994-10-01), Arthur et al.
patent: 5358775 (1994-10-01), Horn III
patent: 5374453 (1994-12-01), Swei et al.
patent: 5506049 (1996-04-01), Swei et al.
patent: 0443400 (1991-08-01), None
patent: 1161755 (1969-08-01), None
patent: 1321428 (1973-06-01), None
patent: 2240985 (1991-08-01), None
patent: 49-29337 (1974-03-01), None
patent: 1138256 (1989-05-01), None
MIL-P13949F, Military Specification,Plastic Sheet, Laminated, Metal Clad (For Printed Wiring Boards), General Speciication For( Mar. 10, 1981) (superseding MIL-P-13949E (Jul. 15,1071), MIL-P-
Arthur David J.
Swei Gwo S.
Cantor & Colburn LLP
Kuhns Allan R.
World Properties, Inc.
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