Patent US5250356A successfully refreshed from Google Patents.
US5250356A
Expired / Lapsed
US
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Cookware coating system
Assignee: EIDP Inc
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Filing: 1992-08-28
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Granted: 1993-10-05
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Expires: 2012-08-28
Abstract
Abstract Metal cookware coated with a multilayer system including a primer with more Al 2 O 3 and a blend of PTFE and PFA or FEP, a midcoat with less Al 2 O 3 , and a topcoat with PTFE, and processes for preparing such coating systems.
Inventors
- 👤 Kenneth Batzar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:59
CPC Classifications
B; B05; B05D; B05D7/00; B05D7/50; B05D7/56; B05D7/58; A; A47; A47J; A47J36/00; A47J36/02; B05D5/00; B05D5/08; B05D5/083; B05D5/086; C; C09; C09D; C09D127/00; C09D127/02; C09D127/12; C09D127/18; B05D2506/00; B05D2506/10; B05D2506/15; B05D2601/00; B05D2601/20; C08; C08L; C08L27/00; C08L27/02; C08L27/12; C08L79/00; C08L79/04; C08L79/08; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/3154; Y10T428/31544; Y10T428/31678; Y10T428/31681; Y10T428/31692; Y10T428/31699
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
174 words
An article of cookware comprising a metal substrate coated with a scratch-resistant, non-stick coating system wherein said coating system comprises a primer applied to a metal substrate, a midcoat adhered to said primer and a topcoat adhered to said midcoat, said primer comprising about 15 to 35 percent by weight calcined aluminum oxide in the form of particles with an average diameter under 20 microns, about 35 to 70 percent by weight perfluorocarbon polymer comprising 50 to 70 percent by weight polytetrafluoroethylene and 50 to 30 percent by weight copolymer selected from fluorinated ethylene-propylene and perfluoroalkyl vinyl ether copolymer with tetrafluoroethylene, and about 15 to 30 weight percent auxillary heat stable polymer selected from polyamide-imide, polyphenylene sulfide and polyether sulfone, said midcoat comprising about 10 to 20 percent by weight of such aluminum oxide, 90 to 80 percent by weight of such perfluorocarbon polymer but in a ratio in the range of 80 to 90 percent by weight polytetrafluoroethylene and 20 to 10 percent by weight of such copolymer, and said topcoat comprises polytetrafluoroethylene.
Claim 2
Dependent Claim
174 words
An article of cookware comprising a metal substrate coated with a scratch-resistant, non-stick coating system wherein said coating system comprises a primer applied to a metal substrate, a midcoat adhered to said primer and a topcoat adhered to said midcoat, said primer comprising about 15 to 35 percent by weight calcined aluminum oxide in the form of particles with an average diameter under 20 microns, about 35 to 70 percent by weight perfluorocarbon polymer comprising 50 to 70 percent by weight polytetrafluoroethylene and 50 to 30 percent by weight copolymer selected from fluorinated ethylene-propylene and perfluoroalkyl vinyl ether copolymer with tetrafluoroethylene, and about 15 to 30 weight percent auxillary heat stable polymer selected from polyamide-imide, polyphenylene sulfide and polyether sulfone, said midcoat comprising about 10 to 20 percent by weight of such aluminum oxide, 90 to 80 percent by weight of such perfluorocarbon polymer but in a ratio in the range of 80 to 90 percent by weight polytetrafluoroethylene and 20 to 10 percent by weight of such copolymer, and said topcoat comprises polytetrafluoroethylene.
Claim 3
Dependent Claim
26 words
The article of claim 1 wherein the perfluorocarbon polymer of the primer comprises about 55 to 65 percent polytetrafluoroethylene and about 45 to 35 percent copolymer.
Claim 4
Dependent Claim
22 words
The article of claim 2 wherein the perfluorocarbon polymer of the primer comprises about 60 percent polytetrafluoroethylene and about 40 percent copolymer.
Claim 5
Dependent Claim
11 words
The article of claim 2 wherein the copolymer is fluorinated ethylene-propylene.
Claim 6
Dependent Claim
15 words
The article of claim 4 wherein the copolymer is perfluoroalkyl vinyl ether copolymer with tetrafluoroethylene.
Claim 7
Dependent Claim
24 words
The article of claim 1 wherein the perfluorocarbon polymer of the midcoat comprises about 85 percent polytetrafluoroethylene and about 15 percent of such copolymer.
Claim 8
Dependent Claim
11 words
The article of claim 6 wherein the copolymer is fluorinated ethylene-propylene.
Claim 9
Dependent Claim
15 words
The article of claim 6 wherein the copolymer is perfluoroalkyl vinyl ether copolymer with tetrafluoroethylene.
Claim 10
Dependent Claim
38 words
A process of producing the article of claim 1 wherein the primer is applied by spraying and is dried before applying the midcoat and the system is cured at elevated temperature after the coating system has been applied.
Claim 11
Dependent Claim
37 words
The process of claim 9 wherein the formulations sprayed onto the dried primer to form the midcoat and topcoat include a decomposable polymer and an oxidation catalyst that aids in the decomposition of such polymer during curing.
Claim 12
Dependent Claim
33 words
The process of claim 9 wherein the dry film thickness (DFT) of the primer is about 13 to 22.5 μm and the DFT of the coating system is about 32.5 to 45 μm.
Claim 13
Dependent Claim
21 words
The process of claim 11 wherein the DFT of the primer is 1.5 to 2.0 times the DFT of the midcoat.
References Cited (Backward Citations)
US3936569A
Cited
US4180609A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-10-04 | 1997-04-05 | 1997-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-04 | 2001-04-05 | 2001-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-04 | 2005-04-05 | 2005-10-05 | $7700.00 | Window Closed / Lapsed |