Patent GB-1474059-A (GB)
Title: Process for preparing aromatic polyesters
IPC: C08G63/64
Filed: 1974-08-06
Abstract: 1474059 Aromatic polyesters TEIJIN Ltd 6 Aug 1974 [7 Aug 1973 24 May 1974 25 May 1974 21 June 1974 22 June 1974] 34609/74 Heading C3R A process for preparing a linear aromatic polyester comprises (1) reacting in the molten state (A) at least one aromatic dicarboxylic acid or ester-forming derivative thereof; (B) at least one diphenol, and (C) at least one dihydroxy compound or carboxylic acid ester thereof or polymer of said ester, the dihydroxy compound being a linear or branched C 2 -C 12  aliphatic glycol, an alicyclic glycol, or a compound of the formula  wherein Ar is a divalent group comprising one or more aromatic rings to which the and groups are directly attached, Y is oxygen or a direct bond, and m and n are each 2-6, the amounts of (A), (B) and (C) being such that: (1) if (C) is a dihydroxy compound, the amount of (B) is 70-105 mole per cent of (A), the amount of (C) is 1-50 mole per cent of (A) and the total amount of (B) and (C) is 100-130 mole per cent of (A), and (ii) if (C) is an ester or polyester, the amount of (B) is 70-105 mole per cent, the amount of the dihydroxy component of (C) is 1-50 mole per cent, and the total amount of (B) and the dihydroxy component of (C) is 100-130 mole per cent, the mole per cent each being of the total amount of (A) and the acid component of C; and (2) polymerizing the thus obtained polymer in the solid phase. Up to 30 mole per cent of component (A) may be replaced by an aliphatic dicarboxylic acid and/or a hydroxycarboxylic acid or an ester-forming derivative thereof. Step (1) is preferably carried out at 200- 300 C. until the polymer has a reduced specific viscosity of 0À15-0À4, and step (2) is preferably carried out until the polymer has a reduced specific viscosity of at least 0À5. The polymer obtained in step (1) may be subjected to a crystallization treatment, e.g. by a heattreatment or by using a crystallizing solvent before step (2). Preferred components (A) are terephthalic acid or a naphthalene dicarboxylic acid or their esters. Preferred components (B) are 2,2 - bis - (4 - hydroxyphenyl)propane (bisphenol A) and 1,1-bis-(4-hydroxyphenyl) cyclohexane bisphenol Z). Preferred components (C) are neopentyl glycol, 4,4<SP>1</SP> - bis- (# - hydroxyethoxy)diphenylsulphone, 2,2- bis - (4 - # - hydroxyethoxyphenyl)propane 1,1 - bis - (4# - hydroxyethoxyphenyl)cyclohexane, bis - (# - hydroxyethyl)terephthalate or polyethylene terephthalate. When component (A) is a free aromatic dicarboxylic acid step (1) is preferably carried out in the presence of a diaryl carbonate in an amount of at least 150 mole per cent of component (A). In the examples polyesters are prepared as above from (1) diphenyl terephthalate, bisphenol A and any one of the following: neopentyl glycol, ethylene glycol, 4,41 - bis - (# - hydroxyethoxy)diphenyl sulphone, bis - (# - hydroxyethyl)terephthalate or 1,1 - bis - (4 - # - hydroxyethoxyphenyl) cyclohexane and optionally bisphenol Z, in the presence of titanium tetrabutoxide as catalyst; or from (2) diphenylnaphthalene 2,6-dicarboxylate, bisphenol A and either neopentyl glycol or 2,2-bis-(4-#-hydroxyethoxyphenol)propane or polyethylene terephthalate in the presence of titanium tetraisopropoxide. Polyesters are also prepared from either naphthalene 2,6-dicarboxylic acid or terephthalic acid, bisphenol A, neopentyl glycol, diphenyl carbonate in the presence of titanium tetrabutoxide. Other examples are described.