Fall 2001 Vol. 3, No. 1

U.S. Patents

Issued After July 1, 2000

Resin Composition for Powder Paints
U.S. Patent 6,090,890
Issued: July 18, 2000
Inventors: Ichiro Murakami, et al
Assigned to: Dow Corning Toray Silicone Co. Ltd.

This patent is for a resin composition that has an excellent curability and excellent electrostatic properties (wrap-around) for powder coatings and that provides cured coatings having an excellent appearance, weathering resistance and mechanical properties, comprising (A) epoxy-functional branched organopolysiloxane and (B) a compound bearing a functional-group reactive with the epoxy group.

Method for Applying Powder Paint
U.S. Patent 6,099,898
Issued: Aug. 8, 2000
Inventors: Jeffrey Joyce, et al
Assigned to: Haden Inc.

An apparatus and process for allowing a powder coating system to utilize various colors of reclaimed powder overspray by collecting it in a common reclaim collector system. The reclaimed powder is then applied to a workpiece as a basecoat to attain a portion of the total film build required. The remainder of the film thickness is then applied in subsequent application of virgin powder.

Thermosetting Powder Paint Composition
U.S. Patent 6,121,378
Issued: Sept. 19, 2000
Inventors: Takahisa Miyawaki, et al
Assigned to: Mitsui Chemicals Inc.

Disclosed is a thermosetting powder topcoat composition having excellent weathering resistance and storage stability. It comprises 100 parts by weight of an acrylic copolymer having an epoxy group, and 0.01 to 2.0 parts by weight of an organic modified polysiloxane containing at least one functional group, at least two silicon atoms and no radical-polymerizable unsaturated bond.

Powder Coating, Method for Coating Same and Coating Film Obtained Therefrom
U.S. Patent 6,130,281
Issued: Oct. 10, 2000
Inventors: Shinji Seo, et al
Assigned to: Nippon Paint Co. Ltd.

A powder coating comprising a film-forming resin as a main component, said powder material having a volume-average particle size of not more than 30 microns and containing particles having a particle size not more than one-fifth of said volume-average particle size, in a proportion of not more than 5 weight percent. When the powder material is charged by corona discharge method or frictional electrification method, sprayed on a coating object to allow electrostatic adhesion and heated, a coating film can be obtained that has a uniform thickness on a coating object having a complicated shape including nonplanar parts.

Transparent Powder Coating Compositions for Protecting Surfaces
U.S. Patent 6,132,883
Issued: Oct. 17, 2000
Inventors: Joseph M. McGrath, et al
Assigned to: 3M Innovative Properties Co.

Powder coating compositions are described containing a blend of ionomers and polyethylene copolymers which fuse at temperatures of about 150°C or below and are durable, weatherable, solvent-resistant and thereby provide transparent protective coatings on substrates such as signs, particularly traffic signs and license plates.

Wrinkled Epoxy Powder Coating With Methylenedisalicylic Acid, Its Homolog and Lewis Acid
U.S. Patent 6,133,384
Issued: Oct. 17, 2000
Inventors: Owen H. Decker, et al
Assigned to: Morton International Inc.

An epoxy coating powder composition and a method for controlling the denseness of cured wrinkle finish patterns are provided by the use of a curing agent mixture comprising a blocked Lewis acid, methylenedisalicylic acid and a ring-substituted homolog thereof wherein the ratio of methylenedisalicylic acid and the ring-substituted homolog is from about 50:50 to about 2:98 by weight.

Method of Powder Coating a Substrate
U.S. Patent 6,136,370
Issued: Oct. 24, 2000
Inventors: Jeno Muthiah, et al
Assigned to: Morton International Inc.

In substrates such as wood, having sharp edges, corners and other surface discontinuities, in a front appearance surface, the process of nonfunctional machining, such as formation of grooves, is performed on the rear nonappearance surface adjacent the surface discontinuities. Coating powder is applied, e.g., electrostatically, to the appearance surface of the substrate, and the coating powder fused or fused and cured to form a continuous coating on the appearance surface of the substrate. The rear surface machining reduces cracking of the coating at the front surface discontinuities. In some cases, nonfunctional machining is distributed over the entire nonappearance surface of the workpiece to promote outgassing of volatiles to the nonappearance surface, thereby eliminating outgassing-caused defects in the coating formed on the appearance surface.

Nonhazing UV-Curable Powder Coatings Containing Crystalline Resins
U.S. Patent 6,136,882
Issued: Oct. 24, 2000
Inventors: Andrew T. Daly, et al
Assigned to: Morton International Inc.

This invention provides a UV-curable powder coating composition comprising a particulate blend of a noncrystalline unsaturated polyester base resin, a crystalline unsaturated cross-linker resin co-polymerizable with the base resin, and a photoinitiator, that exhibits reduced or eliminated hazing in the cured coating formed therefrom upon being cured at low temperatures demanded by certain heat-sensitive substrates. This is accomplished by incorporating in the powder composition a recrystallization or haze inhibitor that is comprised of a crystalline epoxy resin. When this powder blend is melted for curing, the crystalline cross-linker resin visually appears to separate and recrystallize out of the molten powder less completely than it does in the absence of the recrystallization or haze inhibitor. This prevents a visible haze from developing on the surface of the coating upon curing with UV radiation.

Powder Coating Composition Including an Epoxy-Functionalized Silane Resin
U.S. Patent 6,140,419
Issued: Oct. 31, 2000
Inventors: Christine Barglik-Chory, et al
Assigned to: Fraunhofer-Gesellschaft zur Forderung der Angewandten Forschung E.F.

The invention pertains to a powder lacquer composition containing epoxy reactive polymers as binders and epoxy-functional siloxane resins as hardeners as well as additives, if required, such as pigments and/or fillers and/or thermal stabilizers and/or additives such as flow-promoting agents and degassing agents, whereby the hardener is a compound that is prepared by the hydrolysis and condensation of an organo-silane of an epoxy-functionalized silane.

Powder Coating of Non-Crystalline and Crystalline Epoxy Resins
U.S. Patent 6,140,430
Issued: Oct. 31, 2000
Inventors: William G. Ruth, et al
Assigned to: Morton International Inc.

Provided are low-temperature curing thermosetting epoxy powder coating compositions comprising at least one noncrystalline epoxy resin, at least one crystalline epoxy resin, a curing agent and a cure catalyst. Coatings made from such powder compositions exhibit a substantial reduction in bubble entrapment, enough to prevent a visible haze from forming in the coating, when cured at low temperatures demanded by brass substrates, while the powders from which the coatings are made still exhibit good storage stability and melt-processability.

Method of Color-Matching Powder Coating and Coating Method Using Color-Matched Powder Coating
U.S. Patent 6,146,145
Issued: Nov. 14, 2000
Inventors: Takayuki Itakura, et al
Assigned to: Kyocera Mita Corp.

A method of blending a light-transmittable powder coating that is colored in at least one color and a colorless light-transmittable powder coating that is not colored, and dry-blending the powder coatings, to color-match the powder coatings, capable of reproducing colors that could not be reproduced in conventional powder coatings, for example, light, transparent or brilliant colors.

Method of Applying a Powder Coating to a Length of a Lignocellulosic Material
U.S. Patent 6,146,710
Issued: Nov. 14, 2000
Inventors: Michael Windsor Symons
Assigned to: Windsor Technologies Ltd.

A method of applying a powder coating to a length of a lignocellulosic material. The method comprises impregnating the length of lignocellulosic material with an impregnating composition: (i) to a dicarboxylic anhydride or a tricarboxylic anhydride dissolved in nonaqueous solvent; (ii) an isocyanate thermosetting resin dissolved in a nonaqueous solvent; or (iii) a combination of (i) or (ii). Any excess impregnating composition is then removed from the lignocellulosic material. Nonaqueous solvent is also removed, and the impregnated lignocellulosic material is placed in either an electrostatic field or in a fluidized bed, and a powder coating composition is applied thereto so that the powder coating composition adheres to the lignocellulosic material. The impregnated and coated lignocellulosic material is then subjected to elevated temperatures to polymerize and/or cross-link the resin and cure the powder coating composition. The length of lignocellulosic material may be a sheet of paper, wood or wood veneer. A typical solvent is dichloromethane or liquid carbon dioxide.

Method of Applying a Coating Powder to a Substrate
U.S. Patent 6,153,267
Issued: Nov. 28, 2000
Inventors: Paul R. Horinka, et al
Assigned to: Morton International Inc.

An atomized fluid, such as a mist of water, is applied to a preheated substrate, such as wood, a wood product, paper or ceramic just prior to or contemporaneously with electrostatically applying a coating powder to the substrate. The atomized fluid is absorbed or adsorbed by the substrate so as to enhance the charge-carrying capacity of the substrate to an extent necessary to promote efficient electrostatic application of the coating powder to the substrate.

Process for Preparing an Aqueous Powder Coating Dispersion and Using the Same
U.S. Patent 6,159,556
Issued: Dec. 12, 2000
Inventors: Dietmar Moller, et al
Assigned to: BASF Coatings AG

The present invention relates to an aqueous powder coating dispersion comprising a solid, pulverulent component (A) and an aqueous component (B), in which component A is a powder coating comprising: (a) at least one epoxide-containing binder with a content of from 30 to 45% (preferably from 30 to 35%) of glycidyl-containing monomers and aromatic vinyl compounds if desired (preferably styrene); (b) at least one cross-linking agent, preferably straight-chain aliphatic dicarboxylic acids and/or carboxy-functional polyesters; and (c) if desired, catalysts, auxiliaries, typical powder coating additives, such as degassing agents, leveling agents, UV absorbers, free-radical scavengers and antioxidants. Component B is an aqueous dispersion comprising: (a) at least one nonionic thickener; and (b) if desired, catalysts, auxiliaries, defoaming agents, dispersion auxiliaries, wetting agents, preferably carboxy-functional dispersants, antioxidants, UV absorbers, free-radical scavengers, biocides, small quantities of solvent and/or hygroscopic agents.

European Patents Issued After Jan. 1, 2000

Ultraviolet-Curable Solid Epoxy Resin Compositions
EP 0 667 381
Published: Jan. 12, 2000
Assigned to: Ciba Specialty Chemicals Holding Inc.

A solid composition utilizable as a powder coating material that comprises: (a) a solid oligomeric cationically polymerisable polyglycidyl ether or ester having a glass-transition temperature higher than 40°C; (b) a primary aliphatic polyol as a multifunctional nucleophilic chain transfer agent; and (c) 0.05 to 3 weight percent, based on (a) of a photoinitiator for the cationic polymerisation, characterized that the composition does not contain compounds bearing a primary, secondary or tertiary nitrogen atom in an amount higher than 50% of the compound (c).

Thermosetting Powder Paint
EP 0 696 622
Published: Feb. 23, 2000
Assigned to: Mitsui Chemicals Inc.

A thermosetting powder paint comprising: (a) a copolymer obtained by polymerizing a system containing: (a1) more than 20 parts by weight but not more than 60 parts by weight of an ethylenically unsaturated monomer having, in the molecule, at least one glycidyl group and at least one unsaturated double bond; (a2) 1 to 30 parts by weight of styrene; and (a3) 10 to 79 parts by weight of an ethylenically unsaturated monomer having, in the molecule, neither carboxyl group nor tert-butyl ester group, the total of the monomers (a1), (a2) and (a3) being 100 parts by weight; (b) an aliphatic polycarboxylic acid; and (c) a linear anhydride of an aliphatic polycarboxylic acid.

A Powder Paint Binder Composition
EP 0 703 256
Published: March 8, 2000
Assigned to: DSM NV

A powder paint binder composition of a hydroxyl functional polymer and a cross-linker containing blocked isocyanate groups, characterized in the cross-linker includes: (i) a crystalline compound being blocked hexamethylene diisocyanate, and (ii) an amorphous compound being HDI trimer.
High-Gloss Powder Coatings With Fluoro Resin
EP 0 659 851
Published: March 22, 2000
Assigned to: Fina Research S.A.

Powder coating composition for preparing high-gloss coatings, essentially consisting of: (i) a resin component essentially consisting of (a) from 60 to 90 weight percent of one or more vinylidene fluoride copolymer having a melting temperature below 150°C and a melt viscosity greater than 400 Pa.s and smaller than 1000 Pa.s at 232°C, 1000/sec; and (b) from 40 to 10 weight percent of one or more compatible resins; and (ii) from 1 to 35 parts by weight of one or more pigments per 100 parties by weight of the resin component.

Unsaturated Polyesterurethane-Acrylates as a Binder for Powder Coatings
EP 0 702 040
Published: March 29, 2000
Assigned to: Hoechst Aktiengesellschaft

This patent relates to the use of solid, unsaturated polyesterurethane acrylates having a melting temperature of from 35 to 180°C as binders for powder coatings, the polyesterurethane obtainable by reacting hydroxyalkyl(meth)acrylate, polyisocyanate and polyester polyol, said polyesters may be obtained by condensation of: (a) glycidyl compounds or polyhydric alcohols; and (b) unsaturated acids, their anhydrides or mixtures thereof.

Binders for Powder Coatings
EP 0 702 067
Published: March 29, 2000
Assigned to: Hoechst Aktiengesellschaft

A binder for powder coatings comprising a solid unsaturated polyester, a (meth)acryloyl containing polyurethane, solid flow additive that is reactive under curing conditions having at least one olefinic double bond and at least one polar electronegative group selected from carboxylate ester, carboxamide, carboxylic hydrazide, urethane and urea groups.

Modified Polyester Resin/Organic Peroxide Systems for Powder Coatings
EP 0 891 383
Published: Aug. 23, 2000
Assigned to: E.I. Du Pont De Nemours and Co.

Modified polyester resin/peroxide systems for powder coatings comprising: (a) 55 to 60 weight percent of a polyester resin that originates from the reaction of polycarboxylic acids or anhydrides with polyhydroxylated alcohols, including unsaturated compound(s) selected from (meth)acrylic acid, unsaturated polycarboxylic acid, their esters or their anhydrides, allyl compounds and dicyclopentadiene, with molecular weights of between 2k and 15k and the degree of branching being between 2 and 4; (b) 0.5 to 3 weight percent of an organic peroxide with a minimum curing temperature of between 140 and 190°C.

Polymer Networks and Powder Paint for Obtaining These
EP 0 750 023
Published: Sept. 6, 2000
Assigned to: Mitsui Chemicals Inc.

A thermosetting powder paint composition that comprises: at least one acrylic and/or methacrylic copolymer (A) obtained by polymerization in a reaction system of an ethylenic unsaturated monomer having at least one glycidyl group and at least one unsaturated double bond in the molecule as a monomer (a1) and an ethylenically unsaturated monomer having at least one unsaturated double bond and no glycidyl group in the molecule as a monomer (a2); at least one polybasic carboxylic compound (B) selected from the group consisting of polybasic carboxylic acids (b1) and polybasic carboxylic acid anhydrides (b2); and particles (C) having a core/shell structure each comprising a core having a calculated glass-transition point of 20°C or below, the core being covered at least partially with at least one shell having a calculated glass-transition point of 40°C or above, and said shell substantially having neither epoxy group nor glycidyl group.