Patent GB-1287933-A (GB)
IPC: H01B3/30
Filed: 1969-09-17
Abstract: 1287933 Polyimides RAYCHEM CORP 17 Sept 1969 [18 Sept 1968] 45810/69 Heading C3R Poly(1,13 - tridecamethylene pyromellitimide), (A), is obtained by reaction between (B) pyromellitic dianhydride, or derivative thereof, and (C) 1,13-diaminotridecane. A copolymer also contains 1,12-dodecamethylene pyromellitimide units. The (B) derivative may be the ethyl ester. Approx. equimolar proportions of (B) and (C) may be used to give (A) an I.V. of 0À5-5 dl./g., measured at 70‹ C. in m-cresol (0À5 g./100 ml.). The I.V. may increase by # 1% per min. at 200‹ C. under non-oxidizing conditions. There may be #1% molar excess of (C) or #10 excess of (B). Also present, by wt. based on (C), may be 2À5% capping units (D) derived from a primary aliphatic monoamine (E), a primary aromatic amine (F), an aliphatic anhydride (G) or an aromatic anhydride (H). (E) may be lauryl amine, (F) aniline, (G) succinic anhydride, and (H) phthalic anhydride. (A) may have an elongation of #200% at an extension of 2000% per min. at 25‹ C. (A) may have been cross-linked, e.g. by irradiation, e.g. with high-energy electron radiation. (A) or compositions thereof may contain a crosslinking promoter (I) being a polyfunctional monomer, which may contain a plurality of ethylenically unsaturated bonds, e.g. triallyl trimellitate, cyanurate, or isocyanurate; diallyl phthalate or isophthalate; tetrallyl pyromellitate;, 1,11-dodecadiene; dodecamethylene bis-maleimide; or a p-phenylene bis-maleimide. There may be #10% (I) by wt. based on (A). A free-radical scavenger (J) may be present to inhibit homopolymerization of (I). (J) may be hydroquinone, a hindered hydroquinone, or a phenolic antioxidant. The reaction between (B) and (C) may be performed in the melt or in solution. The solvent may be N,N-dimethylacetamide, N,N - dimethylformamide, N - methyl- 2 - pyrrolidene, dimethyl sulphoxide, or mixtures thereof. The reaction is preferably performed in non-oxidizing anhydrous conditions, e.g. in N 2  at - 20‹ to 70‹ C. initially, and 150-250‹ C. finally. (A) is crystalline and thermoplastic, with crystalline m.p. 263-268‹ C. A composition (K) may comprise (A) and an antioxidant (L), a flame-retardant (M), a pigment (N), and/or a filler (O). Antioxidant (L) may be N,N<SP>1</SP> - di - # - naphthyl - p - phenylenediamine; 1,3,5 - trimethyl - 2,4,6 - tris(3,5- ditert - butyl - 4 - hydroxybenzyl) - benzene; distearyl thiodipropionate; phenyl didecyl phosphite; and/or pentaerythritol tetra-3,5- ditert - butyl - 4 - hydroxy - dihydrocinnamate. (L) may be incorporated by mixing powdered (L) with powdered (A); the mixture may then be pelletized. Flame-retardant (M) may be a bis-imide formed from m- or p-phenylene diamine, m- or p-xylylidene diamine, and/or a chlorine or bromine substitution product thereof, with tetrachloro- or tetrabromo-phthalic anhydride, and is referred to in Specification 1,287,934. Also present may be Sb oxide and TiO 2 . (A) or (K) may be extruded or moulded to form sheets, films, tubing, or wire insulation, which may take the form of heat-shrinkable tubing. Articles made -from (A) may have elastic memory,- as referred to in Specification 1,033,959. (A) may be used in laminates as in Specification 1,287,931. Specifications 982,915, 1,026,510, and Specification 1,287,932 are referred to.