Pigmented polyimide films and methods relating thereto

Abstract

The present disclosure is directed to a base film having a thickness from 8 to 152 microns, a 60 degree gloss value from 2 to 35, an optical density greater than or equal to 2 and a dielectric strength greater than 1400 V/mil. The base film comprises a chemically converted (partially or wholly aromatic) polyimide in an amount from 63 to 96 weight percent of the base film. The base film further comprises a pigment and a matting agent. The matting agent is present in an amount from 1.6 to 10 weight percent of the base film, has a median particle size from 1.3 to 10 microns, and has a density from 2 to 4.5 g/cc. The pigment is present in an amount from 2 to 35 weight percent of the base film. The present disclosure is also directed to coverlay films comprising the base film in combination with an adhesive layer.

What is claimed is: 
     
         1 . A base film comprising:
 A. a chemically converted polyimide in an amount from 63 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 pigment, other than carbon black, present in an amount from 2 to 35 weight percent of the base film; and   C. a particulate matting agent that is alumina, barium sulfate, mixtures of at least two of alumina, barium sulfate and silica, the matting agent:   a. is present in an amount from 1.6 to 10 weight percent of the base film,   b. has a median particle size from 1.3 to 10 microns,   c. has a density from 2 to 4.5 g/cc such that the base film has a 60 degree gloss from 2 to 35.   
     
     
         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(trifluoronnethyl) 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 base film comprising:
 A. a chemically converted polyimide in an amount from 63 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 dye present in an amount from 2 to 35 weight percent of the base film; and   C. a particulate matting agent includes alumina, barium sulfate, or mixtures of at least two of alumina, barium sulfate and silica:   a. is present in an amount from 1.6 to 10 weight percent of the base film,   b. has a median particle size from 1.3 to 10 microns, and   c. has a density from 2 to 4.5 g/cc.   
     
     
         9 . The base film in accordance with  claim 1 , wherein the chemically converted polyimide is created by a chemical conversion process that includes the use of a tertiary amine. 
     
     
         10 . The base film in accordance with  claim 9 , wherein the tertiary amine used in the chemical conversion process is pyridine. 
     
     
         11 . The base film in accordance with  claim 9 , wherein the tertiary amine used in the chemical conversion process is beta-picoline. 
     
     
         12 . The base film in accordance with  claim 1 , wherein the chemically converted polyimide is created by a chemical conversion process that includes the use of an anhydride dehydrating material. 
     
     
         13 . The base film in accordance with  claim 12 , wherein the anhydride dehydrating material used in the chemical conversion process is acetic anhydride. 
     
     
         14 . The base film in accordance with  claim 1 , wherein the base film has a 60 degree gloss from 10 to 35. 
     
     
         15 . The base film in accordance with  claim 1 , wherein the base film has an optical density greater than or equal to 2. 
     
     
         16 . The base film in accordance with  claim 1 , wherein the base film has a dielectric strength greater than 1400 V/mil. 
     
     
         17 . The base film in accordance with  claim 1 , wherein the pigment is present in an amount from 15 to 35 weight percent of the polyimide film. 
     
     
         18 . The base film in accordance with  claim 8 , wherein the dye is present in an amount from 15 to 35 weight percent of the polyimide film. 
     
     
         19 . A base film with an optical density greater than or equal to 2 and a dielectric strength greater than 1400 V/mil, comprising:
 A. a chemically converted polyimide in an amount from 63 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 dye present in an amount from 2 to 35 weight percent of the base film; and   C. a particulate matting agent includes alumina, barium sulfate, or mixtures of at least two of alumina, barium sulfate and silica, the matting agent:   a. is present in an amount from 1.6 to 10 weight percent of the base film,   b. has a median particle size from 1.3 to 10 microns, and   c. has a density from 2 to 4.5 g/cc.   
     
     
         20 . The base film in accordance with  claim 1 , wherein the matting agent includes alumina at 7 to 10 weight percent of the base film. 
     
     
         21 . The base film in accordance with  claim 8 , wherein the matting agent includes alumina at 7 to 10 weight percent of the base film. 
     
     
         22 . The base film in accordance with  claim 19 , wherein the matting agent includes alumina at 7 to 10 weight percent of the base film. 
     
     
         23 . The base film in accordance with  claim 1 , wherein the matting agent includes 10 weight percent barium sulfate based on the base film. 
     
     
         24 . The base film in accordance with  claim 8 , wherein the matting agent includes 10 weight percent barium sulfate based on the base film. 
     
     
         25 . The base film in accordance with  claim 19 , wherein the matting agent includes 10 weight percent barium sulfate based on the base film.