Patent GB-1115506-A (GB)
Title: Polyimide films
IPC: C08G73/10
Filed: 1965-09-03
Abstract: A composite film comprises 2 adjacent layers of polyimides A and B each derived from a diprimary amine and an aromatic tetracarboxylic acid in which the carboxyl group are in 2 pairs the members of each pair being ortho or peri to each other, the mole ratio of the reactants being between 0.95-1.05 and 1.05 : 0.95, polyimide A having the recurring unit <FORM:1115506/C3/1> and polyimide B having a recurring unit of formula <FORM:1115506/C3/2> where R is <PICT:1115506/C3/1> <PICT:1115506/C3/2> <PICT:1115506/C3/3> <PICT:1115506/C3/4> <PICT:1115506/C3/5> <PICT:1115506/C3/6> <PICT:1115506/C3/7> <PICT:1115506/C3/8> R1 is a benzene, naphthalene, diphenyl, anthracene, furan or benzfuran residue, or <PICT:1115506/C3/9> R2 is C1- 3 alkylene, oxygen, sulphur, -SO2-, -CO-, -COO-, -CONH-, -CONR3-, -NR3-, <FORM:1115506/C3/3> R3 and R4 are alkyl or aryl, or substituted alkyl or aryl, R5 is >Ar-R7-Ar1< Ar is a benzene residue, Ar1 is a benzene, diphenyl or naphthalene residue, R7 is oxygen, sulphur, -SO2-, -COO-, -CONH-, -CO- or C1- 3 alkylene and R6 is C7- 10 alkylene or <PICT:1115506/C3/100> The 4 valencies of R and R5 are arranged such that the 2 carbonyl groups in each inside ring are ortho- or perito each other on the aromatic nucleus.  The polyimides may be prepared by treating a diamine with a tetracarboxylic acid or its dianhydride, tetraester, diacid diester, chloride or diamide. Diamines specified include bis-(4-aminophenyl) ether, bis - (4 - aminophenyl) methane, bis - (4 - aminophenyl) propane and a condensate of bis-(aminophenyl) ether (2 mol.) and m-xylene-4,6-disulphonyl chloride.  Acid anhydrides specified include pyromellitic anhydride for type A polymers and tetracarboxyl-benzophenone dianhydride for type B polymers. Polyimide B may be coated on to one or both sides of a film of polyimide A. The film may be treated with alkali, polyethylene imine or flames or sparks to improve its adhesion.  B may be added as a liquid precursor, e.g. a polyimino-lactone, a polyamide-acid, a polyamide-ester or a polyamide-amide which is heated to give the polyimide or as a polyimide solution in SbCl3. The coating may be 0.05-1 mil. thick. Example 1 the coating of polyimide B is applied as a solution of the polyamide-acid in dimethyl acetamide.ALSO:The invention comprises articles of two adjacent layers of polyimide, each derivable from an organic primary diamine, and an aromatic tetracarboxylic acid in a molar ratio between 0.95 : 1.05 and 1.05 : 0.95 one polyimide having recurring units of formula: <FORM:1115506/B1-B2/1> where R is:  <FORM:1115506/B1-B2/2> <FORM:1115506/B1-B2/3> <FORM:1115506/B1-B2/4> <FORM:1115506/B1-B2/5> <FORM:1115506/B1-B2/6> <FORM:1115506/B1-B2/7> <FORM:1115506/B1-B2/8> <FORM:1115506/B1-B2/9> and R1 is phenylene naphthylene, biphenylene, anthrylene, furylene, benzfurylene or:  <FORM:1115506/B1-B2/100> where R2 is alkylene of 1 to 3 carbon atoms, - O -, - S -, -SO2 -, - CO -, - COO -, - CONH -, - CON(R3)- - N(R3) -, - Si(R3) (R4) -, - O - Si (R3) (R4) - O -, - P(R3) (0) - or - O - P(R3) (0) - O -, R3 and R4 being alkyl or aryl or substituted alkyl or aryl, and the other polyimide having recurring units of formula: <FORM:1115506/B1-B2/111> where R5 is:  >Ar-R7-Ar1< where Ar is a trivalent benzene radical in which the two radicals not attached to R7 are ortho to one another, Ar1 is a trivalent benzene, diphenyl or naphthalene radical in which the two radicals not attached to R7 are ortho to one another and R7 is - O -, - S -, - SO2 -, - COO -, - CONH -, carbonyl, or C1-3 alkylene and R6 is C7-10 alkylene or <FORM:1115506/B1-B2/122> The article may comprise a film of one polyimide coated on one or both sides with the other polyimide.  The coating may be applied