US4816531A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bismaleimide resin composition containing epoxy resin and a phenolic curing agent therefor
Assignee: Shell USA Inc
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Filing: 1988-03-15
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Granted: 1989-03-28
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Expires: 2008-03-15
Abstract
Abstract A curable composition is provided comprising a bismaleimide resin, an epoxy resin, and a phenolic resin curing agent. The composition can also contain an accelerator for enhanced low-temperature cure. The composition is useful for high-performance applications such as electrical lamination and filament-wound parts.
Inventors
- 👤 Glenda C. Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:35
CPC Classifications
C; C08; C08L; C08L63/00; H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0313; H05K1/032; H05K1/0346
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
125 words
A method for preparing a solvent-borne thermosettable composition comprising blending compositions comprising (a) an epoxy novolac resin solution comprising from about 80 to about 55 weight percent of an epoxy novolac resin, from about 3 to about 10 weight percent of a curing agent for the epoxy novolac resin, said curing agent comprising a phenolic novolac resin, and from about 15 to about 50 weight percent of a first polar organic solvent, based on the weight of the epoxy novolac resin solution; and (b) a bismaleimide resin solution comprising from about 30 to about 40 weight percent bismaleimide resin and from about 70 to about 60 weight percent of a second polar organic solvent different from the first polar organic solvent and comprising dimethyl formamide.
Claim 2
Independent Claim
125 words
A method for preparing a solvent-borne thermosettable composition comprising blending compositions comprising (a) an epoxy novolac resin solution comprising from about 80 to about 55 weight percent of an epoxy novolac resin, from about 3 to about 10 weight percent of a curing agent for the epoxy novolac resin, said curing agent comprising a phenolic novolac resin, and from about 15 to about 50 weight percent of a first polar organic solvent, based on the weight of the epoxy novolac resin solution; and (b) a bismaleimide resin solution comprising from about 30 to about 40 weight percent bismaleimide resin and from about 70 to about 60 weight percent of a second polar organic solvent different from the first polar organic solvent and comprising dimethyl formamide.
Claim 3
Dependent Claim
34 words
The method of claim 1 in which the epoxy novalac resin has as average of from about 2 to about 5 vicinal epoxide groups per molecule and a molecular weight greater than about 500.
Claim 4
Dependent Claim
21 words
The method of claim 2 which further comprises blending (c) from about 0.05 to about 2 weight pecent of an imidazole.
Claim 5
Dependent Claim
15 words
The method of claim 2 in which the first polar solvent is methyl ethyl ketone.
Claim 6
Dependent Claim
40 words
The method of claim 4 in which the phenolic novolac resin is a bisphenol-A novolac having a weight per phenolic group of about 60 to about 500 and an average of more than about 2 phenolic hydroxyl groups per molecule.
Claim 7
Dependent Claim
14 words
The method of claim 1 in which the bismaleimide resin is an N,N'-unsaturated bismaleimide.
Claim 8
Dependent Claim
12 words
The method of claim 3 in which the imidazole is 2-methyl imidazole.
Claim 9
Dependent Claim
12 words
The method of claim 7 in which the bismaleimide is N,N'-4,4'-diphenylmethane bismaleimide.
Claim 10
Dependent Claim
17 words
The method of claim 1 in which the epoxy resin is a normally-solid bisphenol-A novolac epoxy resin.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |