Morton International, Inc.

Other

Douglas S Richart

Charles P Tarnoski

Andrew T Daly

Paul R Horinka

The invention discloses a method by which a fluid heat reactive resin system is formulated below the melting point of the resin. This permits the application of coatings and the formation of shapes and powders from the fluid heat reactive system. Liquefied gases are used to solvate resins so that curing agents, hardeners, pigments and flow control agents, and especially curing agents which are too reactive to be mixed with the resins above the melting point of the resins may be dispersed in the resins. After dispersion, the fluid heat reactive resin system remains in a deformable state under ambient conditions for a transient processing time. The transient processing time is established and maintained by the inclusion of plasticizers and high boiling solvents in the heat reactive resin system.

Resin mixtures and dispersions

The surfaces of particulate polymers are modified by tackifying the surfaces with a liquid that is normally a gas at room temperature. The treatment is carried out while the gas is in its supercritical range and the surfaces of the particulate polymers are at temperatures below the glass transition temperature (Tg) of the polymers. The surface modifications can include adhering solids to the surfaces, altering the surface configuration of the particles and increasing the size of the particles by controlled agglomeration.

Methods and means for modifying the surfaces of polymeric solids

Methods and means for grinding materials to fine powders in a media mill in which the materials are ground while immersed in a liquid. In the preferred embodiments, the liquid is a gas at room temperatures and pressures, the materials are resin mixtures and the fine powders are predominantly in a size range of from about 10 to about 40 micrometers. Other benefits may be achieved if the gas is in a supercritical state.

Process and apparatus for the preparation of fine powders

The use of an amine salt of trifluoromethanesulfonic acid as a catalyst for the curing of hydroxyl-functional resins provides a wrinkle finish. The hydroxy-function may be present in polyesters, epoxies, and acrylate or methacrylate resins, among others. The polyester resins which are able to provide such a finish have a hot plate melt flow of at least about 50 mm but if it is more than 150 mm, the gel time of the resin must not be more than about 280 seconds. The minimum gel time in the case of polyesters is about 30 seconds.

Wrinkle finish powder coatings

The hardness and appearance of an in-mold coating for a molded article of cured unsaturated polyester are improved by the addition of melamine and/or benzoguanamine to an unsaturated polyester powder coating composition and subjecting the modified powder coating to a molding temperature of from about 260.degree. F. to about 340.degree. F. and a pressure of from about 650 psi to about 2000 psi for from 1 to 12 minutes. From about 5 to about 40 parts of the melamine and/or benzoguanamine per hundred parts by weight of the coating resin is used.

In-mold coatings with improved performance

The hardness and appearance of an in-mold coating for a molded article of cured unsaturated polyester are improved by the addition of melamine and/or benzoguanamine to an unsaturated polyester powder coating composition and subjecting the modified powder coating to a molding temperature of from about 260.degree. F. to about 340.degree. F. and a pressure of from about 650 psi to about 2,000 psi for from 1 to 12 minutes. From about 5 to about 40 parts of the melamine and/or benzoguanamine per hundred parts by weight of the coating resin is used.

A flake-containing coating powder is obtained by admixing a coating powder that based upon a thermosetting resin and metallic or non-metalic flake. The powder and flake are mixed at a temperature in the range of above the softening temperature of the thermosetting resin of the coating powder but below the melting temperature of the thermosetting resin and with sufficient mechanical shear to prevent agglomeration of the coating powder particulates. Mixing is for a time sufficient to embed at least about 75% by weight of the flake into the coating powder.

Thermosetting resin-based coating powders containing metal flakes

Significant improvements in the coating characteristics of electrostatic fluidized beds are obtained by limiting the weight of the fines in the coating powder to certain maximum levels, e.g., no more than 10% by weight of minus 38 micrometer particles. The improvements include faster build rates, higher deposition weights, and deeper penetration into holes, slots or other cavities of the substrate.

Growing community of inventors

Reading, PA, United States of America

Douglas S Richart