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US3862897A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of forming high elongation polymide-imide films

Assignee: Rhone Poulenc SA
•
Filing: 1972-10-18
•
Granted: 1975-01-28
•
Expires: 1992-10-18
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Abstract

Abstract Polyamide imide films having a high elongation at break, and suitable for insulating electrical conductors which are to be subjected to stress, are made from polyamideimides comprising structural units of formula: IN WHICH R is a trivalent organic radical containing at least two carbon atoms and Q is a divalent radical containing at least one benzene nucleus, and are characterised by a uniplanar axial structure. They can be made by giving a film of the polyamide-imide a treatment in which (a) it is stretched at 100*-350*C. while it contains at least 1%, preferably 5-30%, of solvent and (b) it is then given a supplementary heat treatment at 100*-350*C, while preventing shrinkage in any planar direction throughout the treatment.

Inventors

  • 👤 Jean Gattus
  • 👤 Maurice Mallet

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-24 16:04
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/005; B29K; B29K2079/00; B29K2079/08; B29K2079/085

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 18 words
A process according to claim 1, in which the film is stretched while it contains 5-30% of solvent.
Claim 2
Dependent Claim 16 words
A process according to claim 1, in which the film is stretched in two directions successively.
Claim 3
Dependent Claim 72 words
A process according to claim 1, in which the film which is to be treated is made by spreading on a support a solution, in the solvent which is to be present in the film while it is stretched, of the polyamide-imide, removing sufficient solvent to form a solid film which still contains the amount of solvent which is to be present during the stretch, and removing the film from the support.
Claim 4
Dependent Claim 46 words
A process according to claim 4, in which the support is of metal and the solution of the polyamide-imide contains also at least 0.5% by weight of an aromatic di-, tri- or tetra-carboxylic acid anhydride, and at least 0.5% by weight of an aromatic diprimary amine.
Claim 5
Dependent Claim 27 words
A process according to claim 1; in which the film contains 5-30% of at least one of the organic polar solvents N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulphoxide and N-methylcaprolactam.
Claim 6
Dependent Claim 29 words
A process according to claim 6, in which the film is made of a polyamide-imide which is the reaction product of (a) an aromatic carboxylic acid anhydride of formula:
Claim 7
Dependent Claim 32 words
A process according to claim 6, in which the film is made of a polyamide-imide which is the reaction product of trimellitic anhydride and 4,4''-diisocyanato-diphenyl-ether or 4,4''-diisocyanato-diphenylmethane, and contains N-methylpyrrolidone as solvent.
Claim 8
Dependent Claim 29 words
A process according to claim 6 in which the film is made of a polyamide-imide which is a reaction product of (a) an aromatic carboxylic acid anhydride of formula:

References Cited (Backward Citations)

US3541038A Cited
US3502762A Cited
US3717696A Cited
US3619461A Cited
US3600361A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-01-27 1978-07-29 1979-01-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-01-27 1982-07-29 1983-01-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-01-27 1986-07-29 1987-01-28 $7700.00 Window Closed / Lapsed

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