U.S. Patents
Issued After Jan. 1, 1999

Process for the Production of a Powder Coating, Apparatus for Carrying Out the Process, and Powder Formulation for Carrying Out the Process
U.S. Patent 5,855,965
Issued: Jan. 5, 1999
Inventors: O. Molerus, et al
Assigned to BASF Lacke + Farben AG
This powder coating production process involves spraying a suspension of powder particles. The spray jet is directed onto the substrate to be coated, characterized in that: 1) a suspension of powder particles in a liquefied gas is employed, the gas having been liquefied under a pressure of not more than 20 bar; and 2) the liquid gas is vaporized before, during or after the spraying of the suspension.

Process for Manufacturing Thermosetting Resin Particles for Powder Coating Use
U.S. Patent 5,856,377
Issued: Jan. 5, 1999
Inventors: H. Sato and Y. Harada
Assigned to Nippon Paint Co. Ltd.
A process has been developed for manufacturing thermosetting resin particles that exhibit improved antiblocking property and workability in powder coatings. The process includes providing a suspension of the thermosetting resin particles in an aqueous medium and an emulsion or dispersion of a vinyl-based polymer having a relatively high Tg, respectively. The thermosetting resin particles are then treated with the emulsion while the resin particles are still suspended in or wetted with the aqueous medium to adhere the vinyl-based polymer onto the resin particles forming a shell layer. The resin particles are dried for use in the powder coating.

Powder Coating Compositions
U.S. Patent 5,856,378
Issued: Jan. 5, 1999
Inventors: J. Ring, et al
Assigned to Courtaulds Coatings (Holdings) Ltd.
This patent involves a powder coating composition suitable for providing a coating having certain appearance or performance attributes. The composition includes composite particles that are agglomerates of individual particulate components fused or bonded together into composite particles. The composite particles are air-fluidizable and can be applied to a substrate by electrostatic spray without causing the individual particles in the composite particles to break down under the mechanical and/or electrostatic forces associated with their application to a substrate.

Composite particles of almost any desired color can be formed by agglomerating individual powder particles of various colors. To prevent a speckled effect, the individual powder particles must be very fine, typically < 10 mm, prepared by jet milling. Composite particles containing other additives, such as metallic flakes, catalysts, texturizing, charge control or other modifiers, can also be prepared by this process.

Radiation-Curable Powder Coatings for Heat-Sensitive Substrates
U.S. Patent 5,877,231
Issued: March 2, 1999
Inventors: K.M. Biller and B.A. MacFadden
Assigned to Herberts Powder Coatings
This patent describes powder coatings that cure by exposure to radiation, typically ultraviolet radiation, in a form suitable for deposition onto substrates, typically electrostatically. It is expected that such powder coatings would be particularly useful in coating heat-sensitive substrates, because heating the powder coating to elevated temperatures is not necessary to effect cure. Free-radical-curable coatings are described using specific chemical formulations of acrylourethane resins, unsaturated polyester resins and mixtures, in combination with morpholino-containing, phenol-containing and ketal-containing photoinitiators.

Nonblooming Polyester Coating Powder
U.S. Patent 5,880,223
Issued: March 9, 1999
Inventors: N. Shah, et al
Assigned to Morton International Inc.
A powder coating composition suitable for curing at low temperatures without the formation of a surface haze ("blooming") is based on a carboxy-functional polyester resin in which the polyol 2-butyl, 2-ethyl, 1-3 propane diol (BEPD) is present at a level of 2 to 25 mole percent of the hydroxyl functionality relative to total hydroxyl functionality of the hydroxyl-functional monomers forming the polyester resin.

Powder Coating, Powder Coating Process and Powder Coated Article
U.S. Patent 5,879,755
Issued: March 9, 1999
Inventors: M. Takahashi, et al
Assigned to Dainichiseika Color & Chemicals Manufacturing Co.
Utilizing powders of only three primary colors-yellow, red and blue-or optionally five primary colors including black and white, it is possible to match any desired color. The primary color powders are prepared in five particle-size ranges, depending on the coating thickness desired and applied utilizing a specially designed electrostatic fluidized bed. The powder particles have a range of volume resistivity from 1010 to 1017 ohm.cm., preferably in the range of 10¹¹ to 1015 ohm.cm.

Two-Component Powder Coating System and Method for Coating Wood Therewith
U.S. Patent 5,907,020
Issued: May 25, 1999
Inventors: G.D. Correll, et al
Assigned to Morton International Inc.
Wood is electrostatically coated with a thermosetting powder coating system in which a mixture of a self-curing epoxy resin and a catalyst is extruded. The resin/catalyst and a low-temperature curing agent are pulverized, and the powders are blended with conventional additives to make a powder coating that can be deposited on a wood substrate and heated to cure. The mixture of resin and catalyst does not cure within the extruder, but it cures at low temperatures by the separate addition of the curing agent. A small amount of the low-temperature curing agent, insufficient to cause substantial curing during extrusion, may be used in place of the catalyst.

Process for Coating Metal Substrates With Primer and Coating Powders
U.S. Patent 5,891,515
Issued: April 6, 1999
Inventors: J.Y. Dutheil and E. Perraud
Assigned to Elf Atochem S.A.
This patent describes a process for
preparing a metal/plastic composite. The process consists of prime coating at least
a portion of a metal substrate with one
or more layers of an adhesion-primer
powder that consists of a solid thermo-setting resin. A conventional powder application technique is used to apply the powder. The coated substrate is then
heated to a temperature sufficient to melt a surface coating powder to be subsequently applied, immersing the coated
substrate into a fluidized bed of a sur-
face coating powder for a time sufficient to give the thickness of surface coating desired. Powder Coating Composition
U.S. Patent 5,898,043
Issued: April 27, 1999
Inventors: M. Uemae, et al
Assigned to Nippon Carbide Kogyo Kabushiki Kaisha
A powder coating composition is comprised of a resin powder made up of a film-forming resin and a cross-linking agent. The resin powder has a volume-average particle diameter of 3 to 17 microns and a shape factor (SF) of 100.5 to 160. This powder coating composition can form a coating film having luster and smoothness and can be applied in a thin film.

Heat-Resistant Powder Coating Composition
U.S. Patent 5,905,104
Issued: May 18, 1999
Inventors: W.G. Eklund, et al
Assigned to H.B. Fuller
A protective coating composition has been developed for use on substrates such as steel, aluminum and iron. This composition provides abrasion, corrosion, heat and electrical resistance; ultraviolet protection; and good initial adhesion. It can be particularly useful for coating high-temperature stacks, mufflers, manifolds, boilers, ovens, furnaces, steam lines, heat exchangers, barbecue equipment, cooking utensils and other
similar parts.

This invention also provides a powder coating composition containing a hydroxyl-functional silicone resin, a glycidyl-
functional acrylic resin and an optional flow-control agent.

European Patents
Issued After Jan. 1, 1999

Modified Polyester Resin/Organic Peroxide Systems for Powder Coatings Which Are Applicable to Temperature-Sensitive and Metallic Substrates
EP 0 891 383A
Published: Jan. 20, 1999
Inventor: J.L. Barrio Diloy
Assigned to Herberts & Co. GmbH
These powders are comprised of: (a) a polyester resin that is a hydroxylated or carboxylated polyester with unsaturation in its chain; and (b) an organic peroxide with a minimum curing temperature of between 140 and 190°C (the relative proportions of resin and organic peroxides being 55 to 60% by weight of resin based on the final composition and 0.5 to 3.0 % by weight of organic peroxide based on the final formulation). These systems are designed for powder coating temperature-sensitive substrates such as plastics and metals, especially aluminum, using the systems currently existing in industry.

Powder Coatings and Methods for Forming a Coating Using the Same
EP 0 899 024A
Published: March 3, 1999
Inventors: M. Sagawa, et al
Assigned to Intermetallics Co. Ltd.
This method for forming coatings includes the steps of making the powder coating adhere to an adhesive layer previously formed on the surface of a material to be coated. The powder layer is then heated, forming a coating.

Weather-Resistant Resin Composition for Powder Coating
EP 0 906 941A
Published: April 7, 1999
Inventors: S. Miyake, et al
Assigned to Nissan Chemical Co. Ltd.
This invention relates to a resin composition for powder coating, having high impact resistance, weathering resistance and storage stability. The resin contains a carboxyl group containing resin and bis (beta-methylglycidyl) terephthalate as a curing agent. The resin also contains a ring-opening polymerization inhibitor for effectively inducing a curing reaction.

A High-Solids and Powder Coatings From Hydroxy-Functional Acrylic Resins
EP 0 907 689
Published: April 14, 1999
Inventor: G. Shao-hua
Assigned to Arco Chemical
High-solids and powder coatings are disclosed. The high-solids coatings consist of an acrylic resin; a melamine, silane, or polyisocyanate cross-linking agent; an organic solvent; and optionally, a pigment and a cross-linking catalyst. The acrylic resin is comprised of recurring units of an allylic alcohol or propoxylated allylic alcohol, a vinyl aromatic monomer, and one or more acrylate monomers. Powder coatings of the invention comprise an acrylic powder resin having a Tg within the range of about 40 to about 80°C. These coatings are economical. They are designed as exterior coatings, especially automotive coatings, with improved weatherability and an excellent balance of physical properties compared with commercial clearcoats.

Stabilizers for Powder Coatings
EP 0 897 958
Published: Feb. 24, 1999
Inventors: H. Lauer and R. Pitteloud
Assigned to Ciba Geigy
Hindered-phenolic stabilizers of specific composition are effective in preventing discoloration of powder coatings at high temperatures, especially in gas-fired ovens. (Original in German)

A Powder Coating With Colour Effect Depending on Viewing Angle
EP 0 891 396
Published: Jan. 20, 1999
Inventors: A Schonfeld and E. Dietz
Assigned to Clariant GmbH
This patent describes a powder effect coating with a color impression depending on the viewing angle, consisting essentially of one or more nonsetting cholesteric liquid crystalline polymers or essentially of at least one nonsetting nematic and at least one nonsetting cholesteric liquid crystalline polymer.

Process for Coating a Board or Paper-Like Substrate With a Powder Paint Composition
EP 0 895 552A
Published: Feb. 10, 1999
Inventors: T.A. Misev and P.A. Steeman; D. Schulze-Hagenest, et al
Assigned to DSM NV, F.A. Michael Huber Muenchen
The invention relates to a process for coating a board or paper-like substrate with a powder paint composition. The powder paint particles are first charged by friction or induction in the presence of magnetic or nonmagnetic particles, are next transported and then applied to the substrate or applied to a transfer medium and subsequently transferred to the substrate. An electric field between the substrate and the transfer medium is used to effect the transfer. The powder paint composition, based on solid particles of a radiation-curable binder, is cured or fused to obtain a powder coating. Preferably, the substrate is paper or cardboard.