Polyimide insulation with improved arc track resistance

• US 5,104,966 A
• Filed: 06/13/1989
• Issued: 04/14/1992
• Est. Priority Date: 06/13/1989
• Status: Expired due to Fees

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: David, Harris B.
• Primary Examiner(s): Kight, III, John
• Assistant Examiner(s): Hampton-Hightower, P.
• Application Number:
  US07/365,395
• Time in Patent Office: 1,036 Days
• Field of Search: 528/125, 528/128, 528/170, 528/172, 528/173, 528/188, 528/206, 528/208, 528/229, 528/310, 528/322, 528/330, 528/350, 528/353
• US Class Current: 528/310
• CPC Class Codes: C08G 73/1042 Copolyimides derived from at least two different tetracarboxylic compounds or two different diamino compounds
• CPC Class Codes: H01B 3/306 Polyimides or polyesterimides
• CPC Class Codes: Y10T 428/31721 Of polyimide

Abstract

Novel polyimide based films are disclosed that are resistant to arc tracking and that include aromatic dianhydrides together with aromatic diamines and aliphatic diamines. The compositions contain from 5 to 20 percent by weight of the aliphatic diamine. These compositions maximize the thermal aging capability of the polyimide. The compositions are useful as films and laminates for wire and cable.

Claims

1. In an improved copolyimide film of:

(a) an aromatic tetracarboxylic acid; and

(b) at least one aromatic diamine;

the improvement comprising the addition of

(c) at least one aliphatic diamine;

wherein said aliphatic diamine is present from 5 to 20 percent by weight based on components (a), (b), and (c), and wherein said copolyimide film is arc track resistant.

2. The film of claim 1 wherein component (a) is pyromellitic acid.

3. The film of claim 1 wherein component (b) is 4,4'"'"'-diaminodiphenylether.

4. The film of claim 1 wherein component (c) is selected from the group consisting of linear or branched aliphatic and cycloaliphatic diamines having from 4 to 13 carbon atoms.

5. The film of claim 4 wherein component (c) is present in an amount of from 6 to 15 percent by weight based on components (a), (b), and (c).

6. The film of claim 4 wherein component (c) is present in an amount of from 7 to 10 percent by weight based on components (a), (b), and (c).

7. The film of claim 1 wherein component (c) is selected from the group consisting of 1,6-diaminohexane, 1,12-diaminododecane, 1,5-diamino-2-methylpentane, 1,5-diaminopentane and 1,4-diaminobutane.

8. In an improved copolyimide film of:

(a) pyromellitic acid; and

(b) 4,4'"'"'-diaminodiphenylether;

the improvement comprising the addition of

(c) 1,6-diaminohexane;

wherein said 1,6-diaminohexane is present from 5 to 20 percent by weight based on components (a), (b), and (c), and wherein said copolyimide film is arc track resistant.

9. The film of claim 8 wherein component (c) is present in an amount of from 7.5 to 9 percent based on the weight of components (a), (b), and (c).

10. A process for the preparation of an arc track resistant copolyimide film, comprising:

(a) reacting an aromatic tetracarboxylic acid with at least one aromatic diamine and at least one aliphatic diamine, said aliphatic diamine being present from 5 to 20 percent by weight based on the reactants, to form a copolyamide acid; and

(b) converting said copolyamide acid to form an arc track resistant copolyimide film.

11. In an improved copolyimide film of:

(a) 3,3'"'"',4,4'"'"'-biphenyltetracarboxylic acid; and

(b) 4,4'"'"'-diaminodiphenylether;

the improvement comprising the addition of

(c) at least one aliphatic diamine;

wherein said aliphatic diamine is present from 5 to 20 percent by weight based on components (a), (b), and (c), and wherein said copolyimide film is arc track resistant.