Verfahren zur Herstellung eines Polyesterharzes

摘要

New copolyesters are made by reacting together (a) 60 to 75 mol. per cent of terephthalic acid (or an ester-forming derivative thereof); and (b) 25 to 40 mol. per cent of hexahydroterephthalic acid (or an ester-forming derivative thereof); with (c) a molar excess of a glycol of formula HO(CH2)nOH, where n is 2 to 10. Reaction is continued until the polyester has a specific viscosity of at least 0.4, as measured at 25 DEG C. on a 1% solution of the resin in a 60:40 mixture of phenol and tetrachloroethane. Examples describe the manufacture of polyesters by reacting dimethyl terephthalate, dimethyl hexahydroterephthalate and ethylene glycol. The polyesters are used in the manufacture of laminates (see Division B5).