GB984522A - Superpolyesters - Google Patents

Abstract

A soluble, fusible, linear polyester with intrinsic viscosity of at least 0.5 is formed of four structural units-(1) 25-45% of p-phenylene, (2) 5-25% of o- or m-phenylene, or o,o1-biphenylene, (3) 20-45% of isophthalate, and (4) 5-30% of terephthalate, the sum of (1) and (2) being 1-1.05 times that of (3) and (4), and the sum of (1) and (4) being no greater than 70% of the total. The polymers may be prepared from the appropriate dihydric phenols and aromatic dicarbonyl halides in certain solvents (Specification 984,523) or by the ester-interchange one or two-stage process in the same solvents. The solvents are benzophenone, m-terphenyl, chlorinated or brominated biphenyls, chlorinated or brominated diphenyl oxides, chlorinated or brominated naphthalenes. All four reactants may be reacted at once or one or more acid materials may be reacted with one or more dihydric phenols and the other reactants added later, or two separate polyesters may be prepared and then co-condensed. Minor amounts of monohydric phenols or monoboric acid halides may be added as chain-stoppers. Suitable chain-stoppers are phenol, cresols, xylenols, ethylphenol, p-hydroxy-phenylbenzoate, benzoyl chloride, bromide, or iodide, toluoyl chloride, naphthoyl chloride, biphenylcarbonyl chloride, or when free hydroxyl groups are desired in the polymer, hydroquinone, or resorcinol. Example (1) describes preparation of random copolymers by simultaneous reaction, in mixed monochlorobiphenyls, of mixtures of hydroquinone, o,o1-dihydroxybiphenyl, iso-phthalyl chloride and terephthalyl chloride; (2) is similar, the two phenols and isophthalyl chloride being first reacted together, and the intermediate reacted with terephthalyl chloride; (3) is similar to (1), using hydroquinone and resorcinol as the two phenols, and mixed trichlorobiphenyls as reaction medium; (4) prepares intermediates from resorcinol and terephthalyl chloride in mixed trichlorobiphenyls, and continues the reactions after addition of hydroquinone and isophthalyl chloride; (5) prepares poly - p - phenylene - m - phenylene isophthalate terephthalate copolymers using different combinations of three of the appropriate reactants in the first stage and the fourth reactant in the second stage. The products may be shaped, e.g. to fibres or films which may be transparent, by pressing or casting. They are useful for coating or impregnating compositions, e.g. as wire enamels, for electrical insulation, or as adhesives, e.g. for laminates. Specification 984,521 also is referred to.