E.i. Dupont De Nemours and Company

Peter L Huesmann

Michael Fryd

Vinci Martinez Felix

Allan Harold Olson

The invention provides for sprayable powder comprising friable granules of agglomerated primary particles of non-fibrillatable fluoropolymer and, optionally, at least one other component, the powder having a bulk density of at least 20 g/100 cc and average particle size of 5 to 100 micrometers. The sprayable powder is preferably free of water immiscible liquid, and more preferably free of halocarbon liquid. Included among the other components are inorganic fillers, pigments, high temperature resistant polymer binders. In another embodiment, the invention provides for a sprayable powder comprising friable granules of agglomerated primary particles of a first non-fibrillatable fluoropolymer and at least one other non-fibrillatable component. The invention further provides for a process for preparing the sprayable powder by spray drying a liquid dispersion. In a preferred embodiment, the process includes densifying the granules of agglomerated primary particles that result from spray drying. Densifying may be carried out by mechanical compaction or by contacting the granules with a heated gas to form a fluidized bed. Optional steps of comminution and heat treatment may be employed to achieve a desired bulk density and particle size for specific applications.

Sprayable powder of non-fibrillatable fluoropolymer

The invention relates to a composition applicable as a undercoat for a non-stick coating on a substrate, comprising (a) inorganic filler of ceramic particles, the particles having an average particle size of 1 micrometer or less and an aspect ratio of not greater than 2.5, (b) adhesion promoter wherein the weight proportion of inorganic filler to adhesion promoter is in the range of 5:1 to 1.7:1, and (c) from 0 to 25 wt. % of a fluoropolymer based on the weight of the composition of the undercoat layer after baking.

Highly filled undercoat for non-stick finish

Coating dispersions for articles containing either (a) a tetrafluoroethylene homopolymer having a standard specific gravity of at least 2.250 and a melt viscosity of 3.times.10.sup.8 to 3.times.10.sup.9 Pa.multidot.s or (b) a non-melt-fabricable tetrafluoroethylene copolymer having a standard specific gravity of at least 2.165 and a melt creep viscosity of 1.times.10.sup.7 to 1.times.10.sup.9 Pa.multidot.s.

Tetrafluoroethylene polymer dispersion composition

An aqueous dispersion contains melt-fabricable fluoropolymer particles and acrylic copolymer particles, said acrylic copolymers having a decomposition temperature of less than 340.degree. C., wherein the dispersion contains about 75 to about 95 wt % of fluoropolymer and about 5 to about 25 wt % of acrylic copolymer, based on combined weights of the two polymers. Coated articles comprise a substrate coated with a primer layer, optional intermediate coats, and a topcoat with at least the topcoat being formed from the aqueous dispersion.

Growing community of inventors

Wilmington, DE, United States of America

Peter L Huesmann