Method for making particulate filled composite film
AssigneeRogers Corporation
InventorsGwo S. Swei, David J. Arthur
Life of this patent
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Abstract
A method for making a particulate filled polymeric matrix composite film includes mixing a polymeric matrix material with a dispersion of particulate filler in a carrier liquid to form a casting composition and adjusting the viscosity of the casting composition to retard separation of the particulate filler from the composition. A layer of the viscosity-adjusted casting composition is cast on a substrate and the layer is consolidated to form the particulate filled polymer matrix composite film. Films made by the method include very thin, e.g. less than 1.0 mil, fluoropolymeric matrix films highly filled with very small diameter, preferably spherical, particles for use as, e.g. dielectric substrate materials in laminar electrical circuits.
Claims41
A method for making a particulate filled polymer matrix composite film, comprising:
- mixing the polymer with a dispersion of a particulate filler in a carrier liquid comprising water to provide an aqueous casting composition wherein said casting composition includes relative amounts of polymer and filler effective to provide a composite film having greater than 15 volume percent filler particles;
- adding a surfactant to the casting composition to modify the surface tension of the carrier liquid so that the carrier liquid wets the filler particles and adding a viscosity and modifier to adjust the viscosity of the casting composition to retard separation of the particulate filler from the composition to provide a stabilized, homogeneous casting composition;
- 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 method for making a composite laminar electrical circuit material, comprising:
- forming a casting composition comprising an aqueous codispersion of fluoropolymer particles and glass or ceramic filler particles, said casting composition including relative amounts of the fluoropolymer particles and filler particles effective to provide a particulate filled fluoropolymer matrix composite film having greater than 15 volume percent filler particles;
- adding a surfactant to the casting composition to modify the surface tension of the carrier liquid so that the carrier liquid wets the filler particles and adding a viscosity modifier to adjust the viscosity of the casting composition to retard separation of the particulate filler from the composition to provide a stabilized, homogeneous casting composition;
- casting a layer of the casting composition onto a substrate;
- and
- drying the cast layer on the substrate to form the composite laminar electrical circuit material, said composite laminar electrical circuit material including a substrate layer and a particulate filled fluoropolymer matrix composite film bonded to the substrate layer.
Dependencies are inferred from the claim text.