US5004627A
Expired / Lapsed
US
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Polyimides for mold release
Assignee: Albemarle Corp
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Filing: 1989-10-10
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Granted: 1991-04-02
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Expires: 2009-10-10
Abstract
Abstract A method of treating the surface of a mold to improve its release characteristics is disclosed. A coating of a polyamic acid solution comprising the reaction product of 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane and an aromatic tetracarboxylic acid or dianhydride or ester derivative thereof is applied to the mold surface. The coating is cured at elevated temperatures to remove the solvent and form the corresponding polyimide.
Inventors
- 👤 J. Kenneth Presswood
- 👤 Alethea H. O'Quinn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:59
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1028; C08G73/1032; B; B05; B05D; B05D5/00; B05D5/08; B28; B28B; B28B7/00; B28B7/38; B28B7/384; B29; B29C; B29C33/00; B29C33/56; B29C33/60; B29C33/62; C09; C09D; C09D179/00; C09D179/04; C09D179/08; B05D3/00; B05D3/02; B05D3/0254; B29K; B29K2879/00; B29K2879/08; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31721
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
66 words
A method for treating the working surface of a mold in order to improve its release characteristics comprising (a) coating said working surface with a polyamic acid solution consisting essentially of the reaction product of 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane and an aromatic tetracarboxylic acid or dianhydride or ester derivative thereof; and (b) applying sufficient heat to cure the coating such that the polyamic acid is converted to a polyimide.
Claim 2
Independent Claim
66 words
A method for treating the working surface of a mold in order to improve its release characteristics comprising (a) coating said working surface with a polyamic acid solution consisting essentially of the reaction product of 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane and an aromatic tetracarboxylic acid or dianhydride or ester derivative thereof; and (b) applying sufficient heat to cure the coating such that the polyamic acid is converted to a polyimide.
Claim 3
Dependent Claim
36 words
The method in accordance with claim 1 wherein said aromatic tetracarboxylic acid or dianhydride or ester derivative thereof is at least one of the following pyromellitic acid; benzophenone tetracarboxylic acid; 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane; oxydiphthalic acid; and biphenyltetracarboxylic acid.
Claim 4
Dependent Claim
22 words
The method in accordance with claim 2 wherein 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane is selected from the group consisting essentially of 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]hexafluoropropane and mixtures thereof.
Claim 5
Dependent Claim
21 words
The method in accordance with claim 3 wherein said aromatic tetracarboxylic acid, is pyromellitic acid, its dianhydride or ester derivative thereof.
Claim 6
Dependent Claim
21 words
The method in accordance with claim 3 wherein said aromatic tetracarboxylic acid is benzophenonetetracarboxylic acid, its dianhydride or ester derivative thereof.
Claim 7
Dependent Claim
14 words
The method in accordance with claim 1 wherein said coating is a spray coating.
Claim 8
Dependent Claim
22 words
The method in accordance with claim 6 wherein the solvents for said solution are a mixture of N-methylpyrrolidone and methyl ethyl ketone.
Claim 9
Dependent Claim
23 words
The method in accordance with claim 1 wherein said mold is at a temperature 150° F. or less when said coating is applied.
Claim 10
Dependent Claim
22 words
The method in accordance with claim 8 wherein the coated mold is further heated up to about 225° to about 300° F.
Claim 11
Dependent Claim
23 words
The method in accordance with claim 9 wherein said coating is imidized at a temperature of from about 400° to about 700° F.
Claim 12
Dependent Claim
20 words
The method in accordance with claim 1 wherein the cured coating has a thickness of from 0.1 to 10 mils.
Claim 13
Dependent Claim
62 words
A mold wherein said working surface is coated with a release-improving composition prepared by (a) coating said working surface with a polyamic acid solution consisting essentially of the reaction product of 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane and an aromatic tetracarboxylic acid or dianhydride or ester derivative thereof; and (b) applying sufficient heat to cure the coating such that the polyamic acid is converted to a polyimide.
Claim 14
Dependent Claim
62 words
A mold wherein said working surface is coated with a release-improving composition prepared by (a) coating said working surface with a polyamic acid solution consisting essentially of the reaction product of 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane and an aromatic tetracarboxylic acid or dianhydride or ester derivative thereof; and (b) applying sufficient heat to cure the coating such that the polyamic acid is converted to a polyimide.
Claim 15
Dependent Claim
36 words
The method in accordance with claim 12 wherein said aromatic tetracarboxylic acid or dianhydride or ester derivative thereof is at least one of the following pyromellitic acid; benzophenone tetracarboxylic acid; 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane; oxydiphthalic acid; and biphenyltetracarboxylic acid.
Claim 16
Dependent Claim
22 words
The method in accordance with claim 13 wherein 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane is selected from the group consisting essentially of 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]hexafluoropropane and mixtures thereof.
Claim 17
Dependent Claim
21 words
The method in accordance with claim 14 wherein said aromatic tetracarboxylic acid is pyromellitic acid, its dianhydride or ester derivative thereof.
Claim 18
Dependent Claim
21 words
The method in accordance with claim 14 wherein said aromatic tetracarboxylic acid is benzophenonetetracarboxylic acid, its dianhydride or ester derivative thereof.
Claim 19
Dependent Claim
14 words
The method in accordance with claim 12 wherein said coating is a spray coating.
Claim 20
Dependent Claim
22 words
The method in accordance with claim 17 wherein the solvents for said solution are a mixture of N-methylpyrrolidone and methyl ethyl ketone.
Claim 21
Dependent Claim
23 words
The method in accordance with claim 12 wherein said mold is at a temperature 150° F. or less when said coating is applied.
Claim 22
Dependent Claim
23 words
The method in accordance with claim 19 wherein the coated mold is further heated up to about 225° F. to about 300° F.
Claim 23
Dependent Claim
23 words
The method in accordance with claim 20 wherein said coating is imidized at a temperature of from about 400° to about 700° F.
Claim 24
Dependent Claim
20 words
The method in accordance with claim 12 wherein the cured coating has a thickness of from 0.1 to 10 mils.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-01 | 1994-10-01 | 1995-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-01 | 1998-10-01 | 1999-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-01 | 2002-10-01 | 2003-04-02 | $7700.00 | Window Closed / Lapsed |