Winter 2000 Vol. 2, No. 1

U.S. Patents
Issued After June 1, 1999

Primer Composition for Powder Coating
U.S. Patent 5,916,639
Issued: June 29, 1999
Inventor: H. Ichikawa
Assigned to Daicel Huels Ltd.
This patent describes an emulsion-type primer for powder coating that achieves a good adhesion between a metallic material and a synthetic resin coating and contains water as a medium. It also describes a process for producing a metallic material coated with a synthetic resin by using this primer. This primer comprises an acid-modified diene polymer, an organic amine or ammonia and water. A metallic material coated with a synthetic resin is produced by applying the primer composition onto the metallic surface, curing the same by baking and then coating it with the synthetic resin by fluidized-bed dipping or electrostatically.

Powder Coating and Method for Its Use On Heat-Resistant Substrates
U.S. Patent 5,919,568
Issued: July 6, 1999
Inventor: E. Wolf
Assigned to Huels Aktiengesellschaft
This is a patent for a powder coating and a substrate coated with the same, in which the coating contains a mixture of a pulverulent polyisocyanate component that is a solid at temperatures of less than 50ºC and a liquid at temperatures above 160ºC (of the formula I##STR1## where R, R(C) and n are as described herein) and a pulverulent, organic polyhydroxy component that is a solid at temperatures of less than 507C and a liquid at temperatures above 160ºC and having a ratio of secondary to primary OH groups of at least 3:1. The two components are present in a ratio of equivalents of NCO:OH groups from 0.5:1 to 1.3:1. The second component is selected from the group consisting of bisphenol A-containing epoxy resin, oligoamides containing secondary hydroxyl groups and mixtures thereof.

Levelling Agents for Powder Coatings
U.S. Patent 5,919,845
Issued: July 6, 1999
Inventors: R. Foukes, et al
Assigned to BASF Coatings AG
This relates to a powder coating having improved properties. The coating contains aliphatic polyvinyl ethers from 0.05 to 5% by weight, preferably 0.5 to 1.5% by weight. The preferred polyvinyl ether is polyvinyl ethyl ether. Compared with other flow additives, such as polyacrylates, the polyvinyl ether gives a powder coating improved innercoat adhesion in multicoat systems.

Dual-Thermal and UV-Curable Powder Coatings
U.S. Patent 5,922,473
Issued: July 13, 1999
Inventors: J. Muthiah, et al
Assigned to Morton International Inc.
This is a patent for opaquely pigmented or thick-filmed powder coatings for heat-sensitive substrates, such as wood, wood composites, medium-density fiberboard and plastics. The coatings can be fully cured, especially near the substrate, by a dual-cure system in the powder comprising a thermal initiator, such as a peroxide, along with a UV initiator. The UV initiator cures the surface, while the thermal initiator cures at the substrate. Surprisingly, virtually no pregelation occurs during the heated-melt and flow-out step prior to UV curing. Consequently, the hardened film finish formed on the surface exhibits exceptional smoothness comparable to that of traditional UV-curable powders. The hardened film finish is also fully cured throughout and exhibits exceptional adhesion to the substrate, which cannot be achieved with traditional UV-curable powders that have been pigmented. Although the dual-cure system includes a thermal aspect, these powder coatings are especially suited for coating heat-sensitive substrates. The dual-thermal and UV-curable powders still cure at significantly lower temperatures and significantly faster rates than traditional heat-curable powders, making them safe for coating heat-
sensitive substrates.

Method of Forming a Hidden Identification Using Powder Coating
U.S. Patent 5,925,402
Issued: July 20, 1999
Inventors: W.E. Nacker, et al
Assigned to Morton International Inc.
As a means of providing a decorative or functional patterned coating on a substrate, powder coating is applied to a substrate. Then the powder coating is fused or fused and cured in selected portions by a computer-guided laser. One application of the invention is to fuse powder coating into a resist-pattern for the printed circuitry production.

Electrostatic Powder Coating Method for Road Wheels
U.S. Patent 5,925,419
Issued: July 20, 1999
Inventors: K. Kukisaki, et al
Assigned to Nihon Parkerizing Co. Ltd. and Nissan Motor Co. Ltd.
In this electrostatic powder coating method, a wheel is placed on a supporting jig, and powder is electrostatically applied on the surface of the wheel. Unnecessary powder adhering to the tapered surface of a bolt hole is eliminated by suctioning the air inside the bolt hole through a suction opening of the supporting jig. A coating film can be formed on the road wheel without applying a coating on the tapered surface of the bolt hole.

Powder Coating Composition and Method for Coating a Substrate Using the Same
U.S. Patent 5,925,698
Issued: July 20, 1999
Inventor: T.F. Steckel
Assigned to Lubrizol Corp.
This invention involves a powder coating composition that contains at least one film-forming resin and a nonflatting and skip-enhancing amount of at least one additive. The additive is a noncross-linked reaction product of a hydroxy compound and a carboxylic acid where the reaction product contains at least one ester functionality and at least one straight-chain hydrocarbyl group of about 10 to about 100 carbon atoms. The preferred additive is sorbitan tristearate. The cured powder coatings exhibit lower coefficient of friction and substantial gloss retention.

Radiation Curing of Powder Coatings on Heat Sensitive Substrates: Chemical Compositions and Processes for Obtaining Coated Workpieces
U.S. Patent 5,935,661
Issued: Aug. 10, 1999
Inventors: K.M. Biller, et al
Assigned to Herberts Powder Coatings Inc.
This invention relates to powder coatings that cure by exposure to radiation, typically ultraviolet light. Powder coatings based upon cationically catalyzed resins (typically epoxy resins) are described, including bisphenols; bisphenols modified by novolac; aliphatic-type epoxides including hydrogenated bisphenol-A, glycidyl methacrylic, glycidyl acrylics or related compounds; and vinyl ethers including mixtures of the forementioned compounds. Photoinitiators of sulfonium type, ferrocinium type, iodonium type, triphenolic types and related compounds are also included. Opacifiers, flow agents and plasticizers are also included. Charge additives for improved electrostatic deposition of the powder coating are also described. Degassing agents are also typically included in the formulation, both for degassing the powder coating during cure and to assist in degassing those substrates (such as wood), which tend to form bubbles during cure. Flow agents are also typically included in the formulation. Solidification of photoinitiators prior to use and the addi-tion of hydroxyl polyesters are shown in the present invention to lead to improved curing and coating performance. Additives are also described that permit the powder coating to flow at temperatures below 100ºC, allowing powder coatings to be employed on heat-sensitive substrates such as wood.

Process for Preparation of Heat-Curable Weather-Resistant Polyurethane Powder Coatings and Coatings Thus Obtained
U.S. Patent 5,939,199
Issued: Aug. 17, 1999
Inventor: R. Gras
Assigned to Huels Aktiengesellschaft
This patent involves polyurethane powder coating compositions of high reactivity, containing an isocyanate component that is partially or totally blocked with 1,2,4-triazole, hydroxyl-containing polymers and, if desired, customary auxiliaries and additives, where the isocyanate component is a physical mixture of individual trimers (isocyanato-isocyanurates) of aliphatic and (cyclo) aliphatic and/or cycloaliphatic diisocyanates provide heat-curable weather-resistant coatings.

Thermosetting Powder Coating Composition
U.S. Patent 5,945,487
Issued: Aug. 31, 1999
Inventors: T. Ohkoshi, et al
Assigned to Kansai Paint Co.
The invention provides a thermosetting powder coating composition comprising a vinyl copolymer having a number average molecular weight of 1,500 to 6,000, a molecular weight distribution of 1.0 to 1.5 (as represented by a weight-average molecular weight/a number-average molecular weight and a glass transition temperature of 40 to 100ºC), the copolymer containing at least one species of functional group selected from the class consisting of epoxy group, carboxyl group and hydroxyl group, and a curing agent. The thermosetting powder coating composition of the invention is superior finished appearance of coating film and the blocking resistance.

Electrostatic Powder Coating Method
U.S. Patent 5,955,152
Issued: Sept. 21, 1999
Inventors: S. Yasuda, et al
Assigned to Kao Corp.
An electrostatic latent image formed on a light-sensitive body is developed by making a thermosetting powder coating material adhere under electrostatic force to the light-sensitive body. The powder coating material on the light-sensitive body is transferred from the transfer part of an intermediate transfer body, which is softer than the light-sensitive body and the object to be coated, onto an object to be coated. The powder coating material is thermally set in such a way that it is able to bake onto the object to be coated.

Easily Sievable Powder Coating Composition
U.S. Patent 5,955,530
Issued: Sept. 21, 1999
Inventors: K. Inoue, et al
Assigned to Nippon Paint Co. Ltd.
Finely divided hydrophobic silica powder having a number average particle size from 3 to 10 nm and a BET surface area from 195 to 290 m~/g is dry-blended with particles of a thermosetting resin composition having a volumetric average particle size from 5 to 20 µm in a proportion from 0.05 to 2.0 parts per 100 parts of the resin particles on weight basis. Sieving efficiency of the powder coating composition thus processed is remarkably improved.

Coating Powder for High Temperature-Resistant Coatings
U.S. Patent 5,962,568
Issued: Oct. 5, 1999
Inventors: O.H. Decker, et al
Assigned to Morton International Inc.
A silicone resin for powder coatings has organic substitutents selected from the group consisting of phenyl, methyl, C(2) through C(6) alkyl and mixtures; a viscosity of between 500 and 10,000 cps at 150ºC; a condensable hydroxyl content of between about 2.0 and about 4.5 weight percent; a glass transition temperature of about 55ºC or above; and about 0.1% or less of organic solvent.

Aqueous Dispersions of a Transparent Powder Coating
U.S. Patent 5,965,213
Issued: Oct. 12, 1999
Inventors: L. Sacharski, et al
Assigned to BASF Coatings AG
An aqueous dispersion of a transparent powder coating consisting of a solid powder component and an aqueous component is disclosed. The solid powder component includes at least one epoxy group-containing binder, at least one cross-linking agent, and optionally, catalysts, adjuvants or additives typical for transparent powder coatings. The binder contains 30 to 45% glycidyl containing monomers, and optionally, vinylaromatic compounds such as styrene. The cross-linking agent is preferably a straight-chain aliphatic dicarboxylic acid and/or a carboxy-functional polyester. The aqueous component includes at least one nonionic thickener and optional materials such as catalysts, adjuvants and/or other such materials. The nonionic thickener is preferably a nonionic associative thickener. The invention also provides a process for preparing the aqueous dispersion and a process for coating a vehicle body with the dispersion.

Powder Coating of Epoxy Resin and Epoxidized Polydiene Block Polymer
U.S. Patent 5,969,043
Issued: Oct. 19, 1999
Inventors: R. Maruta, et al
Assigned to Shell Oil Co.
An epoxy resin composition for powder coatings which comprises 40 to 95 parts by weight of a solid epoxy resin having at least two epoxy groups and 5 to 60 parts of an epoxidized polydiene polymer.

European Patents
Issued After March 25, 1999

Multilayered Coating With a Powder Clearcoat, Method for Making Same and Substrates Coated Therewith
EP 0 927 229
Published: March 26, 1999
Inventors: K.B. Allen,et al
Assigned toPPG Industries Inc.
Cured thermoset multilayered composite coatings with a powder clearcoat and a waterborne basecoat have improved chip resistance. The basecoat is dehydrated up to 15 minutes before it is contacted with powder clearcoat composition. The powder coating clearcoat composition has one or more cross-linking agents and when cured has a film thickness in the range of 35 to 100 microns. The basecoat and clearcoat are cured simultaneously. Optionally, one or more primer coats may be beneath the basecoat.

Powder Coating Composition Containing an Epoxy-Functional Silane Resin
EP 0 930 325 A2
Published: July 21, 1999
Inventors: C. Barglik-Chory, et al
Assigned to Fraunhofer-Gesellschaft Zur Forderung Der Angewanten Forshung E.V.
This invention relates to a powder coating composition containing an epoxy-reactive polymer as a binder. Its hardener is an epoxy-functional siloxane resin. Other ingredients can include pigments, fillers, heat stabilizers and additives. (Original in German)

Epoxy Resins and Hybrid Powder Coating Compositions
EP 0 936 236 A2
Published: Aug. 18, 1999
Inventors: A. Wenning and J.V. Weiss
Assigned to Degussa-Huls
This invention is directed to epoxy resin and hybrid powder coating compositions with physical mixtures of hardener of salts of polycarboxylic acids and amines. (Original in German)

Powder Composition and Method for Coating a Substrate Using Same
EP 0 936 251 A1
Published: Aug. 18, 1999
Inventor: T.F. Steckel
Assigned to Lubrizol Co.
This powder coating composition contains at least one film-forming resin and a nonflatting and slip-enhancing amount of at least one additive. The additive is a noncross-linked reaction product of a hydroxy compound and a carboxylic acid where the reaction product contains at least one ester functionality and at least one straight chain hydrocarbyl group of 10 to 100 carbon atoms. The preferred additive is sorbitan tristearate. The cured powder coatings exhibit lower coefficient of friction and substantial gloss retention.

Two-Component Powder Coating System and Method for Coating Wood Therewith
EP 0 942 050 A2
Published: Sept. 15, 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 Repairing Small Defects in Powder Coatings
EP 0 943 373 A
Published: Sept. 22, 1999
Inventors: F. Dannenhauer, et al
Assigned to DaimlerChrysler AG
No abstract available.

Method and Apparatus for Applying Multi-Color Powder
EP 0 945 186 A1
Published: Sept. 29, 1999
Inventors: J.R. Joyce, et al
Assigned to Haden Inc.
This patent involves an apparatus and process for a powder coating system to utilize reclaimed oversprayed powder paint of various colors by collecting it in a common reclaim collector system. The reclaimed powder coating 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 attained in subsequent application of virgin powder.

Powder Coating Composition
EP 0 945 495 A1
Published: Sept. 29, 1999
Inventors: H. Morita, et al
Assigned to Takeda Chemical Industries Ltd.
This patent describes a powder coating composed of a multilayer polymer particle, in which at least one inner layer is a polymer layer having a glass transition temperature (Tg) of no more than 20ºC and the outermost layer is a polymer layer having a Tg of not less than 60ºC. The monomer components forming the polymer layer having a Tg of not over 20ºC are those having an unsaturated double bond in the molecule. Among the monomer components, a cross-linking monomer and a grafting monomer are used, respectively, within the ranges of 0.3 to 5 weight percent and 1 to 10 weight percent, is dispersed in an amount of 1 to 30 parts by weight per 100 parts by weight of the total components other than the multilayer polymer particle. This formula can show excellent dispersibility to various powder coatings and can improve workability and impact resistance of a coat film while maintaining inherent characteristics of a powder coating such as film appearance and antiblocking.