Matte finish polyimide films and methods relating thereto

1. A base film comprising:

A. a chemically converted polyimide in an amount from 71 to 96 weight percent of the base film, the chemically converted polyimide being derived from:

a. at least 50 mole percent of an aromatic dianhydride, based upon a total dianhydride content of the polyimide, and

b. at least 50 mole percent of an aromatic diamine based upon a total diamine content of the polyimide;

B. a low conductivity carbon black present in an amount from 2 to 9 weight percent of the base film; and

C. a matting agent with a density from 2 to 4.5 g/cc that provides a 60 degree gloss from 10 to 35, and:

a. is alumina present in an amount from 7 to 10 weight percent of the base film, or barium sulfate present in an amount of 10 weight percent of the base film and

b. has a median particle size from 1.3 to 10 microns.

2. The base film in accordance with claim 1 wherein:

a. the aromatic dianhydride is selected from the group consisting of:

pyromellitic dianhydride,

3,3′,4,4′-biphenyl tetracarboxylic dianhydride,

3,3′,4,4′-benzophenone tetracarboxylic dianhydride;

4,4′-oxydiphthalic anhydride,

3,3′,4,4′-diphenyl sulfone tetracarboxylic dianhydride,

2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane,

bisphenol A dianhydride, and

mixtures thereof; and

b. the aromatic diamine is selected from the group consisting of:

3,4′-oxydianiline,

1,3-bis-(4-aminophenoxy)benzene,

4,4′-oxydianiline,

1,4-diaminobenzene,

1,3-diaminobenzene,

2,2′-bis(trifluoromethyl)benzidene,

4,4′-diaminobiphenyl,

4,4′-diaminodiphenyl sulfide,

9,9′-bis(4-amino)fluorine and

mixtures thereof.

3. The base film in accordance with claim 1 wherein the chemically converted polyimide is derived from pyromellitic dianhydride and 4,4′-oxydianiline.

4. A multilayer film comprising the base film of claim 1 and an adhesive layer.

5. The multilayer film in accordance with claim 4 , wherein the adhesive layer is an epoxy resin selected from the group consisting of: bisphenol A epoxy resin, cresol novolac epoxy resin, phosphorus containing epoxy resin, and mixtures thereof.

6. The multilayer film in accordance with claim 4 , wherein the multilayer film is a coverlay film.

7. The base film in accordance with claim 1 , wherein the base film has a thickness from 8 to 152 microns.

8. A chemically converted polyimide film comprising:

(1) a chemically converted polyimide in an amount from 71 to 96 weight percent of the film, the chemically converted polyimide being derived from pyromellitic dianhydride and an aromatic diamine;

(2) a low conductivity carbon black present in an amount from 2 to 9 weight percent of polyimide film; and

(3) an alumina or matting agent present in an amount from 7 to 10 weight percent or a barium sulfate matting agent present in an amount of 10 weight percent to provide a 60 degree gloss from 2 to 35, wherein the matting agent has a median particle size from 1.3 to 10 microns, and a density from 2 to 4.5 g/cc.

9. The film in accordance with claim 8 having a thickness from 10 to 40 microns.

10. The film in accordance with claim 9 , wherein the film has a thickness from 10 to 40 microns; and an optical density greater than or equal to 2.

11. The film in accordance with claim 8 , wherein the film is unidirectionally stretched.

12. The film in accordance with claim 8 , wherein the film is bidirectionally stretched.

13. A reduced gloss, chemically converted polyimide film, comprising:

(1) a chemically converted polyimide being derived from pyromellitic dianhydride and an aromatic diamine, wherein,

(i) the polyimide film contains a low conductivity carbon black present in an amount from 2 to 9 weight percent of the film with a mean particle size from 0.2 to 1 micron and a volatile content greater than or equal to 5%;

(ii) the film contains as a matting agent, alumina, in an amount from 7 to 10 weight percent of the polyimide film or barium sulfate in an amount of 10 weight percent of the polyimide film with a median particle size from 1.3 to 10 microns and a density from 2 to 4.5 g/cc; and

(2) the polyimide film has a thickness from 10 to 40 microns, a 60 degree gloss from 10 to 35; and an optical density greater than or equal to 2.

14. A reduced gloss, polyimide film, comprising:

a chemically converted polyimide film of pyromellitic dianhydride chemically converted with an aromatic diamine, the reduced gloss polyimide film has a 60 degree gloss from 10 to 35 and uniform color intensity, a thickness from 10 to 40 microns, an optical density greater than or equal to 2, and contains a low conductivity carbon black with a volatile content greater than or equal to 5%, and 7 to 10 weight percent of alumina an inorganic matting agent or 10 weight percent of a barium sulfate matting agent to achieve the reduced 60 degree gloss that is at least 20 percent less than a thermally converted polyimide film of equivalent composition.

15. The reduced gloss, chemically converted polyimide film of claim 14 , wherein the reduced gloss is at least 30 percent less than a thermally converted polyimide film of equivalent composition.

16. The reduced gloss, chemically converted polyimide film of claim 14 , wherein the reduced gloss is at least 40 percent less than a thermally converted polyimide film of equivalent composition.