Patent GB-822015-A (GB)
Title: Improvements in linear polyesters
IPC: C07C317/44
Filed: 1955-12-01
Abstract: Polyesters having good dielectric properties are the polyesterification products of glycols with mixtures of a p : p1-sulphonyl dibenzoic acid and certain aliphatic dicarboxylic acids in certain molecular proportions.  They may be made by condensing 1 mol. proportion of a sulphonyl dibenzoic diester of formula <FORM:0822015/IV (a)/1> where R1 and R4 are b -hydroxyalkyl radicals containing 2-4 carbon atoms, o -hydroxyalkyl radicals containing 3-12 carbon atoms or alkyl radicals containing 1-6 carbon atoms, plus 3-15 mol. proportion of an aliphatic acid diester of formula R8OOC-(CH2)t-COOR9 where t is 2-18, R8 and R9 are o -hydroxyalkyl radicals containing 2-12 carbon atoms or alkyl radicals containing 1-6 carbon atoms, with an alkylene glycol (or ester thereof) of formula R5OGOR6 where G is a divalent alkylene radical containing 2-10 carbon atoms and R5 and R6 are hydrogen atoms or acyl radicals containing 2-4 carbon atoms, the reactants being employed in such proportions that the ratio of carbalkoxy groups in the diesters to hydroxy or acyl groups in the alkylene glycol (or its ester) is not more than 1 to 1, and the condensation being carried out (a) in the presence of a condensing agent, (b) at an elevated temperature; (c) in an inert atmosphere, and (d) the latter part of the condensation being conducted at a low pressure of the inert atmosphere.  Part of the alkylene glycol may be replaced by an ether glycol (or ester thereof) or formula R5O-(R7-O)q-R7-OR6 where R5 and R6 are hydrogen atoms or acyl radicals containing 2-4 carbon atoms and q is 1-10. Part of the p : p1-sulphonyl dibenzoic acid may be replaced by the m : m1- or m : p1-isomer.  The polyesters may also be made by condensing (Examples 5 and 6) p : p1-sulphonyldibenzoic acid dibutyl ester (0.4 mol.), diethyl azelate (0.6 mol.), and pentamethylene glycol (1.2 mols.) or 2 : 2-dimethylpropanediol-1 : 3 (1.2 mols.); (Example 10) p : p1-sulphonyl dibenzoic acid (1.0 mol.), diethyl azelate (1.5 mols.) and pentanediol-1 : 5 (3.0 mols.); (Example 11) p : p1-sulphonyl dibenzoic acid dibutyl ester (0.4 mol.), diethyl sebacate (0.6 mol.) and hexamethylene glycol (2.0 mols.); (Example 12) p : p1-sulphonyl dibenzoic acid dibutyl ester (0.3 mol.), diethyl adipate (0.7 mol.) and octamethylene glycol (1.9 mol.).  Condensation catalysts which may be used are those specified in Specification 777,220. Polyesterification may be effected in the presence of a solvent, e.g. diphenyl ether, diphenyl, mixed tolyl sulphones, chlorinated naphthalene, chlorinated diphenyl and dimethyl sulpholone.  The polyesters may be used in the manufacture of sheets, tubing, wrapping materials, moulded objects, gaskets, coated fabrics, wire coatings and electrical condensers, but are especially useful as the dispersing medium for the electroluminescent pigment or phosphor in the manufacture of electroluminescent lamps.  Examples describe the manufacture of polyesters from (1), (2), (3), (4) and (7) sulphonyl dibenzoic acid dibutyl ester, diethyl azelate and butanediol, pentanediol, 2 : 2-dimethyl propane diol-1 : 3 or octamethylene glycol; (8) and (9) sulphonyl dibenzoic acid dibutyl ester, diethyl succinate and ethylene glycol or butanediol. Specifications 777,215, 777,216 and 777,218 also are referred to.