Claims
- 1. Resin powder for applying protective coatings, which powder consists of a mixture of resin particles which as stored are free flowing at ordinary room temperature and would pass through a screen having openings not exceeding 200 micrometers, which particles have a softening point of at least 60.degree. C. but fuse, flow and harden quickly when heated to moderately elevated temperatures, 30-80% of the particles being rounded and at magnifications of 100 to 250X having a glossy appearance comparable to that of polished granite and correspondingly 70-20% being rough and at magnifications of 100 to 250X having a granular appearance comparable to that of rough-hewn granite, which mixture of rough and rounded particles enhances electrostatic coating operations.
- 2. Resin powder as defined in claim 1 wherein each individual particle comprises a blend of thermosetting resin and curing agent.
- 3. Resin powder as defined in claim 2 wherein the thermosetting resin is an epoxy resin.
- 4. Resin powder as defined in claim 3 wherein the epoxy resin is a polyglycidyl ether of polyhydric phenol.
- 5. Resin powder as defined in claim 1 wherein the rounded particles comprise at most 40% of the particles in excess of 75 micrometers in diameter, 40-80% of the particles 50-75 micrometers in diameter, and at least 80% of the particles 1-50 micrometers in diameter.
- 6. Powdered resin for applying protective coatings consisting of resin particles which as stored are free flowing at ordinary room temperature and would pass through screen having 177-micrometer openings and would not pass screen having 1-micrometer openings, which particles have a softening point of at least 60.degree. C. but fuse, flow and harden quickly when heated to moderately elevated temperatures, characterized in that 30-80% of the particles are rounded and at magnifications of 100 to 250X have a glossy appearance comparable to the appearance of polished granite and correspondingly 70-20% are rough and at magnifications of 100 to 250X have a granular appearance comparable to the appearance of rough-hewn granite.
CROSS REFERENCE TO RELATED APPLICATION
This application is a division of applicants' copending application Ser. No. 825,925, filed Aug. 19, 1977 now U.S. Pat. No. 4,154,871 issued May 15, 1979, which in turn was a continuation of applicants' application Ser. No. 612,639, filed Sept. 12, 1975, now abandoned.
US Referenced Citations (10)
Divisions (1)
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Number |
Date |
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825925 |
Aug 1977 |
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Continuations (1)
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612639 |
Sep 1975 |
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