Spring 2003 Vol 5, No.1

U.S. Patents

Thermosetting compositions containing carboxylic acid functional polymers prepared by atom transfer radical polymerization
U.S. Patent 6,339,126
Issued: January 15, 2002
Inventors: Barkac, Karen A., et al.
Assigned to: PPG Industries Ohio Inc.

A thermosetting composition comprising a co-reactable solid, particulate mixture of (a) beta-hydroxyalkylamide crosslinking agent, e.g., bis(N,N-di-2-hydroxyethyl)adipamide, and (b)polycarboxylic acid functional polymer, is described. The polycarboxylic acid functional polymer is prepared by atom transfer radical polymerization and has well-defined polymer chain architecture and polydispersity index of less than 2.5. The thermosetting compositions of the present invention have utility as powder coatings compositions.

Powder coatings from cyclic carbonate functional polymers and amine carbamate salts
U.S. Patent 6,339,129
Issued: January 15, 2002
Inventors: Webster, Dean Charles
Assigned to: Eastman Chemical Co.

Curable coating compositions for powder coatings are disclosed, which are composed of a cyclic carbonate functional polymer and a carbamate salt of a multifunctional amine.

Polymerization, compatibilized blending, and particle size control of powder coatings in supercritical fluid.
U.S. Patent 6,340,722
Issued: January 22, 2002
Inventors: Lee, Sunggyu, et al.
Assigned to: The University of Akron

The current process for producing powder coatings can be replaced with a process utilizing supercritical fluids including polymer polymerization, compatibilized blending of powder coating ingredients, and particle size control and classification of the powder coating. This invention replaces the previous process by performing all operations in a supercritical fluid, preferably, carbon dioxide. Polymerization is conducted at any pressure above critical pressure and temperature above critical temperature up to 190ºC. Solubility of the polymer in the supercritical fluid allows for control and narrow distribution of the molecular weight and a polydispersity of about 2 or less. Compatibilized blending is effected by a chemical or a physical technique to encapsulate the powder coating additives in the polymer. Particle size control is effected by stepwise controlled depressurization of the mixing chamber or through controlled depressurization of the material into one or more chambers. The advantages are reduction in the number of processing stages, compatibility between processing stages, utilization of lower-temperature, free-radical initiators for polymerization, small-batch capability for blending vs. set size extruders, utilization of lower temperature crosslinking agents, no fusing, no curing, more homogeneous blending of powder coating ingredients, increased particle size control, and improved gloss and strength of the powder coating.

Process for coating a substrate with a powder paint composition
U.S. Patent 6,342,273
Issued: January 29, 2002
Inventors: Handels, Johannes W. H., et al.
Assigned to: DSM N.V.

The invention relates to a process for coating a 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. They are next transported and are then applied to the substrate, or applied to a transfer medium and subsequently transferred to the substrate, by means of an electric field between the substrate and the means of transport, where after the powder paint composition is cured or fused to obtain a powder coating.

Clear powder coatings
U.S. Patent 6,342,274
Issued: January 29, 2002
Inventors: Schwarte, Stephan, et al.
Assigned to: BASF Coatings AG

The present invention relates to a transparent powder coating material comprising a) at least one epoxy-containing binder with a content of from 20 to 45% by weight, preferably from 25 to 40% by weight of glycidyl-containing monomers and with or without a content of vinylaromatic compounds, preferably styrene, b) tris(alkoxycarbonylamino)triazine and polycarboxylic acids, preferably straight-chain aliphatic dicarboxylic acids and/or carboxy-functional polyesters, as crosslinking agents, and c) if desired, catalysts, auxiliaries, additives typical for transparent powder coating materials, such as degassing agents, leveling agents, UV absorbers, free-radical scavengers, antioxidants.

Powder coating compositions containing transfer efficiency-enhancing additives
U.S. Patent 6,342,551
Issued: January 29, 2002
Inventors: Jolley, Scott T.
Assigned to: The Lubrizol Corp.

This invention relates to a powder coating composition made by combining at least two components comprising (A) a film-forming thermosetting resin composition; and (B) a transfer efficiency-enhancing amount of at least one amide, wherein component (B) is incorporated into the powder coating composition by the addition of component (B) to an extruded composition comprising components other than (B). The invention also relates to a method for coating a substrate using the foregoing powder coating composition.

Nonionically stabilized transparent powder coating dispersion
U.S. Patent 6,344,501
Issued: February 5, 2002
Inventors: Sierakowski, Claudia, et al.
Assigned to: BASF Coatings AG

The present invention relates to an aqueous powder clearcoat dispersion comprising a solid pulverulent component A and an aqueous component B, where component A is a transparent powder coating material and component B is an aqueous dispersion comprising a) at least one nonionic thickener and b) if desired, catalysts, auxiliaries, defoamers, wetting agents, antioxidants, UV absorbers, free-radical scavengers, biocides, small amounts of solvent, leveling agents, neutralizing agents, preferably amines, and/or water retention agents, and c) a dispersant medium in the form of a nonionic polyurethane dispersion.

Method for producing low/medium-gloss appearance with UV-curable powder coatings
U.S. Patent 6,348,242
Issued: February 19, 2002
Inventors: Daly, Andrew T., et al.
Assigned to: Morton International Inc.

Low-gloss appearance in a coating derived from UV-curable powder coatings can be achieved by using UV-curable powder containing crystalline components or blends of crystalline and amorphous components and, after heat-fusing the powders together, allowing the crystalline components in the coating time to flow out and recrystallize to form a matte low-gloss finish at a temperature of about the melting point of the crystalline component before curing with UV radiation.

Method for color matching of powder coating composition
U.S. Patent 6,348,520
Issued: February 19, 2002
Inventors: Ohnishi, Kazuhiko, et al.
Assigned to: Kansai Paint Co. Ltd.

The present invention provides a method for color matching of a thermosetting powder coating composition, the method comprising the steps of (1) dry-blending two or more kinds of starting colored thermosetting powder coating compositions of different colors having an average particle size of 20 microns or less to achieve color matching, and (2) granulating the dryblend to a particle size in the range suitable for powder coating, by heating and agitating the dryblend, or by adding a specific solid binder, or by grinding and classifying a sheet or grains formed by compressing the dryblend. According to the present invention, color matching can be easily made, and a color-matched powder coating composition is obtained that is excellent in application characteristics, finished appearance and film properties.

Matte powder coating
U.S. Patent 6,350,821
Issued: February 26, 2002
Inventor: Alford, William H.
Assigned to: BASF Corp.

A matte powder coating composition including a first carboxyl-functional polyester resin, a second carboxyl-functional polyester resin, and an epoxide-functional crosslinking agent, where the difference in acid values between the first and second carboxyl-functional polyester resins is from about 200 to about 350 mg KOH/g.

Thermosetting powder coating composition
U.S. Patent 6,359,067
Issued: March 19, 2002
Inventors: Miyawaki, Takahisa, et al.
Assigned to: Mitsui Chemicals Inc.

A thermosetting powder coating composition that comprises a resin composition (A) having a sea-island-type microphase separation structure constituted of a continuous phase (a sea phase) comprising an acrylic copolymer and a dispersed phase (an island phase) comprising a thermoplastic elastomer and a curing agent (B) and in which the total amount of a thermosetting elastomer constituting the dispersed phase is in the range of 0.5 to 20 parts by weight with respect to 100 parts by weight of the resin composition (A). This powder coating composition is excellent in chipping resistance, impact resistance, weathering resistance and appearance properties, and it is particularly suitable for the coating of vehicles.

Powder slurry coating composition
U.S. Patent 6,360,974
Issued: March 26, 2002
Inventors: Sacharski, Lawrence, et al.
Assigned to: BASF Corp.

A powder slurry coating composition is prepared by adding individual particulate materials including at least one resin powder to an aqueous medium and then milling the dispersed particulate materials to produce a median particle size of up to about 15 microns. The powder slurry coating composition is used to prepare a coating on a substrate. The coating is equivalent to coatings obtained from powder slurry coating compositions in which the powder is produced by melt mixing in an extruder and grinding the extrudate.

Powder coating composition
U.S. Patent 6,362,267
Issued: March 26, 2002
Inventors: Harashima, Isao, et al.
Assigned to: Dainichiseika Color & Chemicals Mfg. Co. Ltd.

A powder coating composition according to the present invention is used in the coating of a molded product having defects, cavities and the like in its surface. The powder coating composition contains a single film-forming resin or a plurality of film-forming resins selected from the group consisting of an epoxy resin, a polyester resin and an acrylic resin, and at least two fillers having different particle size in a range of 3 to 100 microns. Thus, the powder coating composition is applied directly onto a to-be-coated surface without need for a pretreatment such as the sanding of the surface and the filling of the surface by putty. Therefore, molding defects of the surface can be hidden satisfactorily to form a coated surface of excellent appearance.

Fluoropolymer powder coatings from modified thermoplastic vinylidene fluoride-based resins
U.S. Patent 6,362,295
Issued: March 26, 2002
Inventors: Gaboury, Scott R., et al.
Assigned to: Atofina Chemicals Inc.

An improved blend suitable for powder coating, comprising an acrylic-modified polyvinylidene fluoride polymer and pigment, processes for its preparation and use and coated articles produced there from are disclosed. Use of unpigmented acrylic-modified fluoropolymers to form powder coating and objects so coated are also disclosed.

Method for producing a coating powder composition
U.S. Patent 6,368,725
Issued: April 9, 2002
Inventors: Graf, Knut, et al.
Assigned to: E.I. du Pont de Nemours and Co.

A process for the preparation of a powder lacquer composition based on polyester by heating to a temperature of 120-200ºC polyester precondensates, and/or of monomers usable for their preparation, pigments and wetting additives and/or further additives that are conventionally used for lacquers; homogeneous mixing of the components with the application of shear forces and with the heating temperature maintained dispersing the mixture obtained in a dispersing medium at a temperature equal to or above the melting temperature of the starting components with further polycondensation of the polyester precondensate, and/or of the monomers and cooling of the dispersion. A conventional crosslinking agent for the polyester is added in the temperature range 60 to 140ºC prior to cooling.

European Patents

Method for producing reactive coating powder compositions
Granted: July 17, 2002
EP1032608
Assigned to: E.I. DuPont De Nemours and Co.

Method for producing reactive coating powder compositions by decompressing a composition containing a) a liquefiable low-molecular compound selected from carbon dioxide, alkane, ammonia, nitrogen, fluoroalkane, dialkyl ether, alcohol, dialkylketone, dimethylamine, ethylacetate and mixtures thereof; bi) a combination of base resin(s) and a hardener thereof or bii) a self-curing base resin; whereby the low-molecular-weight compound is mixed in a liquefied state with the b)-component, the resulting solution is homogenized at a time of not more than 5 minutes and the mixture is decompressed under cooling, thereby liberating the low-molecular-weight compound.

Low-gloss polyester coating powder compositions
Granted: July 24, 2002
EP0786503
Assigned to: Morton International Inc.

A coating powder composition comprising a polyester resin and triglycidyl isocyanurate, characterized in that the composition further comprises a) from 2 to 10 parts per hundred parts of resin by weight of an un-neutralized copolymer of ethylene with 5 to 20 wt% (meth)acrylic acid; b) from .2 to 1 parts per hundred parts of resin by weight of a 2-mercapto benzothiazole, metal salts of 2-mercapto benzothiazole and mixtures thereof; and c) from 0 to 10 parts per hundred parts of resin by weight polyolefin wax.

Anticorrosive multilayer coating system for metal surfaces
Granted: July 24, 2002
EP0803297
Assigned to: Akzo Nobel N.V.

An anticorrosive multilayer coating system for metal surfaces, comprising at least a primer coat (a) based on a nonconductive binder, followed by a second or further top coats (b), characterized in that the primer coat (a) is an electroinsulating powder coating layer based on an epoxy resin, alkyd resin, polyester resin, melamine-containing resin, polyurethane resin and/or polyacrylate resin, and, optionally, a filler, pigment and/or adjuvant, and the outer top coat (b) is an electrically conductive powder coating layer based on an epoxy resin, alkyd resin, polyester resin, melamine-containing resin, polyurethane resin and/or polyacrylate resin incorporating .1 to 50 wt% of an electrically conductive resin, filler, pigment and/or adjuvant capable of providing a conductive outer layer with, optionally, a structured and/or wrinkle finish, calculated on the overall weight of this outer layer.

Ball-shaped polyester particles
Granted: July 31, 2002
EP0960152
Assigned to: E.I. DuPont De Nemours and Co.

Polyester particles for use in powder coatings, having an average particle size below 50 æm, characterized that the particles are spherical and transparent, have a monomodal particle size distribution with a span smaller than 2.5 and fusible at temperatures below 200ºC.

Powder varnish composition
Granted: August 7, 2002
EP1023404
Assigned to: E.I. DuPont De Nemours and Co.

Powder coating composition comprising at least 1 part of weight of a component A) consisting of epoxy resin(s) having an epoxy equivalent weight of from 250 to 2,500, one or more curing agent component(s) and a separately prepared particulate component, and at least 50 parts of a component B) comprising a resin having an acid number of from 20 to 70 and/or an OH number of from 10 to 100, one or more curing agents, in a mixing ratio that the sum A+B is 100.

Coating metal pipes with powder
Granted: August 21, 2002
EP0707618
Assigned to: BASF Coatings Aktiengesellschaft

Use of a powder coating as the single-layer exterior coating of metal pipes, comprising epoxy resins, phenolic crosslinking components, catalysts and silicic acid functionalized with glycidyl groups.