Claims
- 1. A method for forming a cured unsaturated polyester surface coating on a cured unsaturated polyester substrate, wherein said coating and substrate are crosslinked across their interface, comprising the steps of:
- A. providing an unsaturated polyester resin coating powder composition consisting essentially of from about 20 to 100 parts by weight of at least one unsaturated polyester resin, from 0 to about 80 parts by weight of at least one copolymerizable second resin, wherein the total proportion of resin is 100 parts by weight, from about 0.01 to about 2 parts by weight per 100 parts resin by weight of a fast initiator having a ten hour half-life at not more than 82.degree. C., and from about 3 to about 7 parts by weight per 100 parts resin by weight of a slow initiator having a ten hour half-life at about 91.degree. C. or more;
- B. providing a mold surface having a temperature between about 127.degree. C. and about 171.degree. C.;
- C. powder coating said composition on said mold surface;
- D. maintaining said composition on said mold surface at said temperature until said coating flows and coalesces to form a partially crosslinked coating, said coating having an outer surface against said mold surface and an opposed inner surface;
- E. contacting said coating inner surface at an interface with a no more than partially crosslinked unsaturated polyester fill resin substrate; and
- F. continuing said contacting step until said coating and said fill resin crosslink across said interface.
- 2. A method for forming a cured unsaturated polyester surface coating on a cured unsaturated polyester substrate, wherein said coating and substrate are crosslinked across their interface, comprising the steps of:
- A. providing an unsaturated polyester resin coating powder composition consisting essentially of about 20 to 100 parts by weight of at least one unsaturated polyester resin, about 0 to 80 parts by weight of at least one copolymerizable second resin, wherein the total proportion of resin is 100 parts by weight, and an amount of an initiator sufficient to initiate cross-linking of said powder composition at a temperature substantially above room temperature, wherein said initiator comprises from about 3 to about 15 parts by weight per 100 parts resin by weight of 1,1'-di(t-butylperoxy)-3,3,5-trimethylcyclohexane;
- B. providing a mold surface having a temperature between about 127.degree. C. and about 171.degree. C.;
- C. powder coating said composition on said mold surface;
- D. maintaining said composition on said mold surface at said temperature until said coating flows and coalesces to form a partially crosslinked coating, said coating having an outer surface against said mold surface and an opposed inner surface;
- E. contacting said coating inner surface at an interface with a no more than partially crosslinked unsaturated polyester fill resin substrate; and
- F. continuing said contacting step until said coating and said fill resin crosslink across said interface.
- 3. The method of claim 2 wherein said composition comprises from about 3 to about 9 parts by weight per 100 parts resin by weight of said initiator.
- 4. The method of claim 2 wherein said composition comprises from about 12 to about 15 parts by weight per 100 parts resin by weight of said initiator.
- 5. The method of claim 2 wherein 1,1'di-(t-butylperoxy)-3,3,5-trimethylcyclohexane is substantially the sole initiator present.
Parent Case Info
This is a divisional of application Ser. No. 100,675, filed on Sept. 24, 1987, now U.S. Pat. No. 4,873,274.
US Referenced Citations (3)
Divisions (1)
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Number |
Date |
Country |
Parent |
100675 |
Sep 1987 |
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