Fall 2000 Vol. 2, No. 3

U.S. patents Issued After Nov. 1, 1999

Continuous Processing of Powder Coating Compositions
U.S. Patent 5,975,874
Issued: Nov. 2, 1999
Inventors: A.T. Daly, et al
Assigned to Morton International Inc.
Systems and apparatus combinations for producing a powder coating are provided wherein a stream of a powder coating precursor, including at least one resin and at least one additional powder coating ingredient, is contacted with a process fluid effective to reduce the viscosity of the powder coating precursor to allow processing of the powder coating precursor at a lower temperature.

Precross-linked Silicone Elastomer Particles With Organopolymer Shells as Formulation Constituents in Powder Coating Materials.
U.S. Patent 5,981,650
Issued: Nov. 9, 1999
Inventors: M. Geck, et al
Assigned to Wacher-Chemie GmbH
The invention relates to the use of precross-linked silicone elastomer particles with an organopolymer shell as the formulation constituent in powder coating material compositions based on thermoplastic or thermosetting binding agents.

Process for Preparing Coating Powder Compositions and Use of Same for Making Coatings
U.S. Patent 5,981,696
Issued: Nov. 9, 1999
Inventors: D. Saatweber, et al
Assigned to Herberts GmbH
The invention concerns a process for preparing powder coating compositions in which one or more base resins and one or more hardeners, each of which is in solid form, is dissolved with a low-molecular compound above its critical pressure and critical temperature. This low-molecular compound is inert with respect to the base resins and hardeners and is in gaseous form under normal operating conditions with respect to pressure and temperature. The pressure of the resultant solution is then reduced, for example, by spraying. The resulting powder coating composition can be sprayed directly onto a substrate to be coated. Powder coatings can also be recycled according to the process of the invention.

Thermosetting Powder Coating Material and Method
U.S. Patent 5,998,507
Issued: Dec. 7, 1999
Inventors: T. Adachi, et al
Assigned to Kansai Paint Co. Ltd.
A method for preparing a thermosetting powder coating material comprising: dispersing and mixing a base resin and a cross-linking agent in a dispersing and/or mixing machine equipped with a decompression device at a temperature in the range of 40 to 200°C to form a dispersed mixture, the dispersed mixture optionally containing a solvent and a pigment, optionally eliminating at least a portion of the solvent under reduced pressure, adding water to the dispersed mixture, reducing the pressure and lowering the temperature of the dispersed mixture to a temperature equal to or less than the softening point of the dispersed mixture, and bringing the dispersed mixture into a powder state or a granule state by dispersion force of the dispersing and/or mixing machine.

Coating Powder for High-Temperature Resistant Coatings
U.S. Patent 5,998,560
Issued: Dec. 7, 1999
Inventors: O.H. Decker, et al
Assigned to Morton International Inc.
A powder coating for providing a high-temperature resistant coating has a silicone resin binder system that is either substantially all silicone resin or an -OH- functional silicone resin adduct plus blocked, multi -NCO- functional curative. The powder coating is pigmented with titanium dioxide, which is either uncoated or coated with a sufficiently low level of an inorganic oxide such that when slurried in water, the pH is 7 or above. The powder coating preferably contains at least 40 phr mica and/or calcium metasilicate, preferably between 2 and about 20 phy aluminum. The powder coating may also contain zinc to protect the underlying substrate from corrosion and high-temperature pigments, particularly ceramic pigments.

Dual-Thermal and UV-Curable Powder Coatings
U.S. Patent 6,005,017
Issued: Dec. 21, 1999
Inventors: A.T. Daly, et al
Assigned to Morton International Inc.
Opaquely pigmented or thick-filmed powder coatings for heat-sensitive substrates, including wood, wood composites such as medium-density fiberboard, and plastics, can be fully cured, especially near the substrate, through the incorporation of 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, which is comparable to that of traditional UV-curable powders. The hardened film finish is also fully cured and exhibits exceptional adhesion to the substrate, which cannot be achieved with traditional pigmented UV-curable powders. 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 to make them safe for coating heat-sensitive substrates.

Nonhazing UV-Curable Powder Coatings Containing Crystalline Resins
U.S. Patent 6,011,080
Issued: Jan. 4, 2000
Inventors: A.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 copolymerizable with the base resin, and a photoinitiator, that exhibits reduced or eliminated hazing in the cured coating formed when cured at low temperatures. This is accomplished by incorporating in the powder composition a recrystallization inhibitor, which is comprised of a crystalline epoxy resin. When this powder blend is melted for curing, all the crystalline resin species tend to separate and recrystallize out of the molten powder slower and less completely than they do in the absence of the recrystallization inhibitor. This prevents a visible haze from quickly developing on the surface of the molten coating before the coating can be cured with UV radiation.

Powder Coating Process Using Two or More Kinds of Powder Paint
U.S. Patent 6,015,585
Issued: Jan. 18, 2000
Inventors: M. Yamaguchi, et al
Assigned to Honda Giken Kogyo Kabushiki Kaisha
Powder coatings of different color brightness not deposited on the work to be coated are recovered as a mixture, and a fresh coating of high- or low-color brightness is added to the mixture to adjust its color brightness and thereby prepare a fresh mixture of medium-color brightness.

Thermosetting Powder Coating Composition
U.S. Patent 6,015,864
Issued: Jan. 18, 2000
Inventors: Koenraadt, Martinus Adrianus Anthonius Maria, et al
Assigned to Akzo Nobel NV
Proposed is a thermosetting powder coating composition comprising a mixture of particles reactive towards one another, optionally in combination with a catalyst, with a portion of the reactive particles comprising a polymer reactive towards oxetane groups while another portion comprises an oxetane groups containing cross-linking agent having an oxetane functionality of more than 1. The quantity of oxetane oxygen in the cross-linking agent preferably is at least 0.4 weight percent. The reactive polymer preferably is a polymer having groups reactive towards oxetane, such as carboxyl, epoxy, oxetane, anhydride and hydroxyl, with preference being given to a polyester or a hydroxypolyacrylate.

Method for Producing Low-Gloss Appearance With UV-Curable Powder Coatings
U.S. Patent 6,017,593
Issued: Jan. 25, 2000
Inventors: A.T. Daly, et al
Assigned to Morton International Inc.
Low-gloss appearance in a coating derived from UV-curable powder coatings can be achieved by using a UV-curable powder containing crystalline resins or blends of crystalline and amorphous resins and after heat-fusing the powders together, allowing the crystalline resins in the coating to cool and recrystallize to a low-gloss finish before curing with UV.

Dual-Thermal and UV-Curable Powder Coatings
U.S. Patent 6,017,640
Issued: Jan. 25, 2000
Inventors: J. Muthiah, et al
Assigned to Morton International Inc.
For abstract, see U.S. Patent 6,005,017.

Powder Coatings From Mixtures of Thermoplastic Vinylidene Fluoride-Based Resins and Polyamide
U.S. Patent 6,018,000
Issued: Jan. 25, 2000
Inventors: B.D. Keeny, et al
Assigned to Elf Atochem North America
Pigmented and unpigmented polymeric resin blends containing up to 45 weight percent polyvinylidene fluoride-based polymer and either polyamide 11 or polyamide 12 having particular usefulness in powder coating of objects are disclosed.

Flexible, Weatherable, Acrylic Coating Powder
U.S. Patent 6,022,927
Issued: Feb. 8, 2000
Inventors: O.H. Decker, et al
Assigned to Morton International Inc.
Coating powder compositions comprise: A) between about 60 and about 90 weight percent, relative to total weight of A + B + C, of an acrylic polymer having a weight average molecular weight of between about 1,000 and about 30,000, a carboxylic acid equivalent weight from about 300 to about 1,000 and a T_g of about 45°C or above; and B) between about 5 and about 30 weight percent, relative to total weight of A + B + C of an adduct prepared from i) between about 20 and 50 weight percent, relative to total weight of i) + ii), of a curing agent reactive with carboxylic acid groups and ii) between about 50 and about 80 weight percent, relative to total weight of i) + ii), of a polyester resin formed primarily from linear aliphatic diols and dicarboxylic acids, the polyester having functional groups reactive with said curing agent i); and C) between about 2 and about 30 weight percent, relative to the total weight of A + B + C of a curing agent reactive with carboxylic acid groups. The sum of unreacted functional groups of adduct B + curing agent C is at a stoichiometric equivalent relative to said carboxylic acid functionality of said acrylic polymer A of between about 0.5 and about 1.5. Using sufficient amounts of an appropriate cure catalyst, the composition may be fused and cured at temperatures of 300°F or below, even 250°F or below, making the coating composition suitable for coating wood and wood products.

Coating Powder for High-Temperature Resistant Coatings
U.S. Patent 6,034,178
Issued: March 7, 2000
Inventors: O.H. Decker, et al
Assigned to Morton International Inc.
A powder coating for producing a high-temperature-resistant coating has a resin system that comprises: A) between about 50 and about 93 weight percent based on total of A + B of a silicone resin; and B) between about 7 and about 50 weight percent based on total weight of A and B of a polyhydroxyl component. The silicone resin A of the coating powder has organic substitutents selected from the group consisting of phenyl, methyl, and mixtures thereof. The polyhydroxyl component B is a polyhydroxyl with average hydroxyl equivalent weight of between 100 and 500, containing an average of at least three hydroxyl groups per molecule.

European Patents Issued After June 1, 1999

Triboelectric Chargeable Coating Powder
EP 0 956 319 A (WO 99/28396
Published: June 10, 1999
Inventors: C. Hilger, et al
Assigned to BASF Coatings AG
The invention relates to triboelectricchargeable coating powders using additives based on benzimidazoles.

Powder Coating Composition Comprising Unsaturated Polyesters and Uses Thereof
EP 0 957 141 A1
Published: Nov. 17, 1999
Inventors: C.E. Ortiz, et al
Assigned to Ferro Corp.
The powder coating composition of the present invention includes a low-temperature mixture of a powder (A) and a powder (B), in which at least the powder A includes an unsaturated polyester resin and a free-radical initiator for initiating polymerization of unsaturated polyester resins in the powder coating composition and the powder B includes a polymerization promoter and methods for making the composition. The powder B may further include unsaturated polyester. The powders A and B are physically mixed at temperatures at which the polymerization promoter would cause the free-radical initiator to initiate polymerization of the powder coating composition. Subsequently, the physically mixed powder coating composition is applied to a substrate and cured, during which the polymerization promoter causes the free-radical initiator to initiate the curing reaction.

Unsaturated Polyester Powder Coatings With Improved Surface Cure
EP 0 957 142 A2
Published: Nov. 17, 1999
Inventors: J. Muthiah, et al
Assigned to Morton International Inc.
Low-temperature-curable unsaturated polyester powder coatings are suited for heat-sensitive substrates with improved surface cure through incorporation of active hydrogen groups into the unsaturated polyester molecule. The unsaturated polyesters containing active hydrogens are derived from ethylenically unsaturated polyfunctional carboxylic acids and active hydrogen containing polyols. Full cure on the surface is obtained without the need for polyethylene waxes or oxygen-reactive curative resins that are commonly employed in order to prevent atmospheric oxygen from inhibiting the free-radical induced cure at the surface of the coating.

Process for the Preparation of Powder Coating Composition
EP 0 962 472 A2
Published: Dec. 8, 1999
Inventors: T. Isozaki, et al
Assigned to Mitsubishi Gas Chemical Co.
A process for the preparation of a powder coating composition, wherein 5 to 90% by weight of at least one monomeric compound selected from glycidyl group containing unsaturated compounds and methyl-glycidyl group-containing unsaturated compounds is co-polymerized with 95 to 10% by weight of an ethylenically unsaturated monomer in methanol to obtain a resin solution. The resin solution is spray-dried to obtain a powdery resin. Alternatively, the resin solution is fed to an extruder having a die and a plurality of vent ports and extruded through the die, while removing volatile matters through the vent ports, to obtain extrudates. The extrudates are pulverized to obtain a powdery resin.

Block Polymer and Powder/Paint Binder Composition
EP 0 962 473 A1
Published: Dec. 8, 1999
Inventors: S. Udding-Louwrier, et al
Assigned to DSM NV
The invention relates to an A-B-C block polymer formulated from an ethylenically unsaturated monomer, the A block and the C block being terminally disposed and the B block being interposed between the A block and the C block; the A block and the C block having cross-linkable functional groups, the B block being essentially free of reactive functional groups. The polymer can be obtained through controlled radical polymerization in the presence of an initiator and a metal complex or a metal-containing compound. The invention also relates to a powder paint composition comprising said A-B-C block polymer.

Process for Preparing an Aqueous Dispersion Coating Material and Process for Preparing a Powder Coating Material
EP 0 962 502
Published: Dec. 8, 1999
Inventors: H. Okazaki, et al
Assigned to Dai Nippon Toryo Ltd.
A process for preparing an aqueous dispersion coating material containing a resin component having a softening temperature from 10 to 250°C, which comprises: A) a step of mixing various starting materials that will be coating film-constituting components to obtain a blend material; B) a step of melting and kneading the blend material at a temperature of at least the softening temperature of the resin component to obtain a homogenized material; C) a step of cooling and solidifying the homogenized material, followed by crushing, to obtain coarse particles; and D) a step of wet-pulverizing the coarse particles in an aqueous dispersant to obtain an aqueous dispersion coating material containing fine particles having an average particle size of at most 10 µm.

The Method for Producing Powder Lacquer Containing Gloss Pigments
EP 0 963 416 (WO 98/37154)
Published: Aug. 27, 1998
Inventor: M. Kieser, et al
Assigned to Merck Patent GmbH
The invention relates to a method for producing powder lacquers containing gloss pigments, characterized in that the starting materials, consisting of standard powder lacquer components and one or more gloss pigments, are placed into the supply chamber of a first container that has a mixing element and is possibly fitted with a thermostatic device, after which a supercritical fluid is introduced into the supply chamber and the starting materials are mixed in the presence of the supercritical fluid. The mixture of standard powder lacquer components, one or several gloss pigments and supercritical fluid is transferred by a distributor to a second container. The distributor has several nozzles with diameter openings from 0.0025 to 2.5 cm. During transfer, the second container is kept at an internal pressure of between 0 and 350 bar and at a temperature of between -85 and 200°C.

Powder Coating Additive, Powder Coating Composition Containing Said Additive and Method for Coating a Substrate Using Said Powder Coating Composition
EP 0 967 255
Published: December 29, 1999
Inventor: T.F. Steckel
Assigned to The Lubrizol Corp.
A powder coating additive composition containing: A) a noncross-linked product made by the reaction of an organic alcohol and a carboxylic acid or a reactive equivalent of the carboxylic acid (the product containing at least one ester functionality and at least one hydrocarbyl group of about 10 to about 100 carbon atoms); and B) a fluoropolymer. The cured coatings exhibit lower coefficient of friction and substantial gloss retention.

Acrylic Powder Coating Including High Homopolymer Glass Transition Temperature Cyclic (Meth) Acrylate Monomer as Viscosity Modifier
EP 0 968 241 (WO 98/42765)
Published: Oct. 1, 1998
Inventors: C. Zezza, et al
Assigned to Rhodia Inc.
A powder coating composition is provided comprising a binder that consists of two components: A) one of the components includes one or more acrylate polymers derived from two or more monomers with the proviso that at least 15% of the two or more monomers comprises a cyclic acrylate monomer having a homopolymer glass transition temperature greater than about 75°C; and B) the other of said components includes one or more cross-linking agents; wherein upon application to a surface and heating thereafter, said coating cross-links and forms a thin irreversible film.

Powder Paint Binder Composition
EP 0971 004
Published: Jan. 12, 2000
Inventors: van Benthem, Rudolfus Antonius Theodorus Maria, et al
Assigned to DSM NV
The invention relates to a radiation curable powder coating binder composition comprising a radiation-curable compound being a mono or multi-valent carboxylic ester of a hydroxyalkylamide group containing compound, in which the carboxylic ester is derived from an ethylenically unsaturated carboxylic acid.

Spherical Particles of a Coating Composition
EP 0 973 822 (WO 98/45356)
Published: Oct. 15, 1998
Inventor: G.K. Kodokian
Assigned to E.I. DuPont De Nemours and Co.
Spherical particles of a copolymer composition comprising a cross-linker and/or coating additives, the particles being especially useful for coating various substrates, and an improved process for making such particles comprising forming the copolymer and unreacted cross-linker and/or other additives in a coating matrix.

Powder Coating Composition Containing Lamellar Pigment and Resin
EP 0 973 834 A (WO 98/46682)
Published: Oct. 22, 1998
Inventors: M. HE, et al
Assigned to Engelhard Corp.
A pigment in the form a platelets made of a reflective metal or of pearlescent type is mixed with a sticky viscous liquid. The resulting pigment can be combined with a powdery film-forming composition, which can be applied electrostatically.

Powder Paint Binder Composition
E P0 975 703 A (WO 98/46690)
Published: Oct. 22, 1998
Inventors: F. Kolduk, et al
Assigned to DSM NV
The invention relates to a powder coating binder composition comprising a polymer that contains endomethylene tetrahydrophthalic acid units and a crosslinker. The polymer has been obtained by preparing an unsaturated polymer in a first step, which then reacts with cyclopentadiene at a temperature between 160 and 220°C in a second step. The polymer preferably contains more than 10 weight percent endomethylene tetrahydrophthalic acid units and is preferably an unsaturated polyester.

Modified Epoxy Resin and Its Use as a Formulating Component for Heat-Curable Compositions, Especially for Powder Coatings
EP 0 980 399 A (WO 98/50447)
Publication Date: Nov. 12, 1998
Inventors: I. Frischinger, et al
Assigned to Ciba Specialty Chemicals Holding Inc.
Modified epoxy resins having a low-melt viscosity, suitable as a formulating component for heat-curable compositions, especially for powder coatings, are obtained by advancing a liquid diglycidyl ether-based resin with a polyester component. The polyester component can be acid-terminated, phenolic or hydroxyl-terminated.

Non-Hazing UV-Curable Powder Coatings Containing Crystalline Resins
EP 0 980 901 A
Published: Feb. 3, 2000
Inventors: A.T. Daly, et al
Assigned to Morton International Inc.
For abstract, See U.S. Patent 6,011,080.

Transparent Powder Coating Compositions for Protecting Surfaces
EP 0 981 585 A (WO 98/50475)
Published: Nov. 12, 1998
Inventors: J.M. McGrath, et al
Assigned to Minnesota Mining and Manufacturing Co.
Powder coating compositions are des-cribed containing a blend of ionomers and polyethylene copolymers that fuse at about 150°C or below and are durable, weatherable and solvent-resistant, providing transparent protective coatings on substrates such as traffic signs and license plates.