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US 7,622,072 B2Granted
Versatile processes for preparing and using novel composite particles in powder coating compositions
AssigneeValspar Sourcing, Inc.
InventorsWalter J. Blatter, James A. Heck, Lowell G. Lindquist
Life of this patent
Estimating the term…
Abstract
Methodology for constructing composite particles from ingredients comprising two or more particulate components. The resultant particles are usefully incorporated into powder coating compositions. The approach also finds utility in other applications, including but not limited to the food, drug, and cosmetics industry. Fluidized particles are subjected to an intense, but relatively brief heating event. This causes associated particles to fusingly assemble into fused composite clusters.
Claims27
A process for preparing composite particles for a powder coating composition, comprising the steps of:
- a. providing a first particle component comprising a plurality of first particles, wherein the first plurality of particles comprises a thermosetting, film-forming resin having a glass transition temperature (Tg);
- b. providing a second particle component comprising a plurality of second particles;
- c. mixing the first and second particle components to form a particle mixture;
- d. fluidizing said particle mixture;
- and
- e. transporting a flow of the fluidized particle mixture through a heating zone such that the fluidized particle mixture enters the heating zone to begin a heating event and exits the zone to end the heating event, said heating event occurring under conditions effective to fuse the first particles to the second particles to provide a plurality of composite particles, wherein the heating zone is at a temperature that is at least 100° F. greater than the Tg of said thermosetting, film-forming resin but the residence time of the thermosetting resin in the heating zone is sufficiently short such that the composite particles retain thermosetting characteristics and can be melted and cured when the composite particles are subsequently coated onto a substrate.
3 more elements
A process for preparing composite particles for a powder coating composition, comprising the steps of:
- a. providing a first particle component comprising a plurality of first particles, wherein the first plurality of particles comprises a film-forming resin having a glass transition temperature (Tg);
- b. providing a second particle component comprising a plurality of second particles, wherein the second plurality of particles comprises a crystalline material that has a melting point that is higher than the Tg of the film-forming resin;
- c. mixing the first and second particle components to form a particle mixture;
- d. fluidizing said particle mixture;
- and
- e. transporting a flow of the fluidized particle mixture through a heating zone such that the fluidized particle mixture enters the heating zone to begin a heating event and exits the zone to end the heating event, said heating event occurring under conditions effective to fuse the first particles and the second particles together to provide a plurality of composite particles, wherein the heating zone is at a temperature that is at least 100° F. greater than the Tg of said thermosetting, film-forming resin and the melting point of the crystalline material, and the residence time of the thermosetting resin in the heating zone is sufficiently short such that the composite particles retain thermosetting characteristics and can be melted and cured when the composite particles are subsequently coated onto a substrate.
3 more elements
A process for preparing composite particles for a powder coating composition, comprising the steps of:
- a. providing a first particle component comprising a plurality of first particles, wherein the first plurality of particles comprises a thermosetting, film-forming resin having a glass transition temperature (Tg);
- b. providing a second particle component comprising a plurality of second particles, wherein one of said first and second particle components constitutes host particles and the other particle component constitutes guest particles, wherein the ratio of the median particle size (volume D50) of the host particles to the guest particles is greater than about 3:1;
- c. mixing the first and second particle components to form an ordered particle mixture;
- d. fluidizing said ordered particle mixture;
- and
- e. transporting a flow of the fluidized particle mixture through a heating zone such that the fluidized particle mixture enters the heating zone to begin a heating event and exits the zone to end the heating event, said heating event occurring under temperature conditions effective to fuse the first particles to the second particles to provide a plurality of composite particles, and wherein the residence time of the thermosetting resin in the heating zone during the heating event is sufficiently short such that the composite particles retain thermosetting characteristics and can be melted and cured when the composite particles are subsequently powder coated onto a substrate.
3 more elements
Dependencies are inferred from the claim text.