Claims
- 1. Method of applying a protective resin coating to an article using a resin powder consisting of resin particles which as stored are free flowing at ordinary room temperature and would pass through a screen having openings not exceeding 177 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, characterized by the steps of
- (a) heat-rounding a controlled portion of pulverized resin particles such that 30-80% of the resultant particles take on a glossy appearance while 70-20% of the particles retain a rough, granular appearance,
- (b) electrostatically depositing the resultant particles on the article, and
- (c) heating the article to a temperature sufficient to fuse the resin powder and provide a protective resin coating.
- 2. Method as defined in claim 1 wherein the heating of step (c) is carried out before step (b).
- 3. Method as defined in claim 1 wherein the resin is a thermosetting resin and the heating of step (c) is continued until the resin of the deposited particles has cured to a thermoset state.
- 4. Method as defined in claim 1 wherein the resin is a thermoplastic resin and step (c) is followed by a cooling step (d) to harden the resin.
- 5. Method of applying a protective resin coating to an article using a resin powder consisting 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, characterized by the steps of
- (a) heat-rounding a controlled portion of pulverized resin particles such that 30-80% of the resultant particles take on a glossy appearance while 70-20% of the particles retain a rough, granular appearance,
- (b) electrostatically depositing the resultant particles on the article, and
- (c) heating the article to a temperature sufficient to fuse the resin powder to provide a protective resin coating.
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of applicants' copending application Ser. No. 612,639, filed Sept. 12, 1975, now abandoned.
US Referenced Citations (20)
Continuations (1)
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Number |
Date |
Country |
Parent |
612639 |
Sep 1975 |
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