3,297,633 United States Patent Office Patented Jan. 10, 1967 1. 2 maximum of seventy weight percent of 4,4'-bis(hydroxy 3,297,633 phenyl)-methane. PREPARATION OF POYESTERS WITH LOW MET The diacid halides of aromatic dicarboxylic acids which WISCOSITY FROM A. MIXTURE OF BISPHENOL can be used in the polycondensation according to the in RaymondSOMERS R. Hindersian, Lewiston, N.Y., and Andrée Jan vention can be obtained by the reaction of aromatic di Conix, Hove-Antwerp, Belgium; said Hindersinn as carboxylic acids with thionyl chloride. Suitable aromatic signor to Hooker Chemical Corporation, Niagara Falls, dicarboxylic acids are among others: N.Y., a corporation of New York, and Said Consix as terephthalic acid signorgium, a to Belgian Gevaert company Photo-Producten N.V., Mortsel, Bel isophthalic acid No Drawing. Filed July 25, 1962, Ser. No. 212,457 O phthalic acid 5 Claims. (C. 260-47) bis(4-carboxy)-diphenyl bis(4-carboxyphenyl)-ether It is known to prepare linear polyesters by polycondens bis(4-carboxyphenyl)-sulphone ing a metal diphenate of a bisphenol of the formula: bis(4-carboxyphenyl)-carbonyl HO-Ar-R-Ar-OH bis(4-carboxphenyl)-methane with a diacid halide of an aromatic dicarboxylic acid of bis(4-carboxyphenyl)-dichloromethane 1,2- and 1,1-bis(4-carboxyphenyl)-ethane the formula: 1,1- and 2,2-bis(4-carboxyphenyl)-propane HOOC-Ar-R-Ar-COOH 1,1- and 2,2-bis(3-carboxyphenyl)-propane wherein each of Ar and Ar' represents a p-phenylene 20 2,2-bis(4-carboxyphenyl)-1,1-dimethyl-propane radical, a m-phenylene radical, one of R and R represents 1,1- and 2,2-bis(4-carboxyphenyl)-butane an alkyl substituted methylene group, an aryl Substituted 1,1- and 2,2-bis(4-carboxyphenyl)-pentane methylene group, or an alkyl- and aryl-substituted methyl 3,3-bis(4-carboxyphenyl)-heptane ene group, a halogenated methylene group, a halo 25 3,3-bis(3-carboxyphenyl)-heptane methyl substituted methylene group, or a carbon atom The polycondensation of the metal diphenates of the making part of a cycloaliphatic ring, and the other of R mixture of isomers of bis(hydroxyphenyl)-methane with and R may also represent such a group or atom, a single diacid halides of aromatic dicarboxylic acids is carried bond, an oxygen atom, a carbonyl group, a Sulphonyl out in the presence as catalysts of one or more compounds group or an alkylene radical. 30 selected from the group consisting of onium compounds In the reaction the metal diphenate of the bisphenol is such as quaternary ammonium compounds, tertiary sul dissolved in water and the diacid halide of the aromatic phonium compounds, quaternary phosphonium com dicarboxylic acid is dissolved in an organic liquid which pounds and quaternary arsonium compounds. These is immiscible with water and which is a solvent or a Swell catalysts are preferably added in amounts between 0.01 ing agent for the polyester to be formed. and 5 percent, calculated on the weight of the mixture of It appears from the intrinsic viscosity values, which metal diphenates used. The most effective catalysts are are at least 0.4 di./g. and which, in Some cases, even Soluble in the aqueous phase as well as in the organic reach 2.5 di./g. that the thermoplastic polyesters obtained phase and may be added to the reaction mixture before, possess very high molecular weights. Moreover, they are during or after mixing of the two phases. soluble in low boiling solvents, e.g., chlorinated aliphatic 40 The polycondensation reaction may be carried out at hydrocarbons, and they can be cast from their solutions temperatures between -10 degrees centigrade and the to colorless, transparent films. The higher the molecular boiling point of the organic solvent used. If a diacid weight, the better the mechanical properties of the poly halide is employed which is sensitive to hydrolysis, it is esters of the films and of other shaped articles manu indicated to cool the reaction mixture to 0 degrees centi factured therefrom. 45 grade or even lower so as to avoid this hydrolysis as much These polyesters, however, can only be injection mold as possible. ed into useful articles with great difficulty. The diffi Water is used as the solvent for the metal diphenates culties are due to the very high melt viscosity of the and halogenated hydrocarbons, such as, e.g., methylene polymers. Indeed, these polymers show melt viscosities chloride, chloroform, 1,2-dichloroethane, 1,1,2-trichloro far in excess of the range which is suitable for conven 50 ethane, sym-tetrachloroethane, methylchloroform, etc., as tional injection molding equipment (17,000 to 50,000 common solvent for the diacid halide and the polyester poises at 300 degrees centigrade). Raising the molding to be formed by the reaction. Other water-immiscible temperature in order to reduce the melt viscosity is not organic solvents such as benzene, toluene, etc., can be practical, because most molding equipment does not gen used in association with the above mentioned solvents. erally operate at temperatures above 300 degrees centi 55 The process may be performed using one or more addi grade. Temperatures exceeding 300 degrees centigrade tional compounds (i.e., compounds additional to the said may also lead to polymer degradation. metal diphenates and/or the diacid halides) which pro It has now been found that polyesters derived from vide elements or groups in minor amounts which enter into bisphenois and aromatic dicarboxylic acids having a low the structure of the final polyester. We would refer, in melt viscosity can be obtained by selecting as one of the 60 particular, to the performance of the process by condens starting materials a mixture of isomeric bis(hydroxy ing with the diacid halides not only the metal diphenates phenyl)-methanes. of the mixture of isomers but also one or more metal According to the invention, linear, thermoplastic, high diphenates of other bis-phenols, e.g., 2,2-bis(4-hydroxy molecular weight, soluble polyesters with low melt vis phenyl)-propane (bisphenol A), and/or by using in con cosity are obtained by polycondensing metal diphenates 65 junction with the diacid halides of aromatic dicarboxylic of a mixture of bis(hydroxphenyl)-methanes dissolved in acids, diacid halides of other dicarboxylic acids and/or water, with one or more diacid halides of aromatic dicar diacid halides of aromatic disulphonic acids and/or di boxylic acids dissolved in an organic liquid which is im acid halides of aromatic monocarboxysulphonic acids. miscible with water and wherein the polyester to be According to the preferred embodiment of the inven formed is soluble to some extent, wherein the mixture 70 tion, the polycondensation is performed between a mix of isomeric bis(hydroxyphenyl)-methanes contains a ture of metal diphenates of isomer bis(hydroxyphenyl)- 3,297,633 3 4 methanes and diacid halides of one or more aromatic Heating in an oxygen containing atmosphere of films dicarboxylic acids, the metal diphenates being selected or other shaped articles from the new polyesters gen so that a maximum of seventy percent of the 4,4'-isomer erally renders these articles insoluble in organic solvents. is present and such that a maximum of eighty percent of Probably a cross-linking reaction occurs which possibly the 2,2'-isomer is present. Using these criteria, polyesters 5 can be attributed to the reactivity of the activated methyl result having reasonably low melt viscosities and yet ene group situated between the two aromatic rings. which are not unduly brittle to be practical in molded When the polyesters are made using both the bisphenol articles. F isomers and bisphenol A, the resistance of the result A suitable starting mixture of isomeric bisphenols may ing copolymers to stress cracking in the presence of be prepared by reaction of formaldehyde with an excess solvents such as acetone, carbon tetrachloride, benzene of phenol. Thus, when reacting formaldehyde with an and ethyl acetate is greatly improved over similar results excess of phenol in the presence of an acidic catalyst, it is with polymers based on bisphenol A. found that the reaction products, in general, consist of The intrinsic viscosities Im of the prepared polymers about 44 percent by weight of 4,4'-bis(hydroxpyhenyl)- were measured at 25 degrees centigrade in sym-tetrachlo-. methane, 53 percent by weight of 2,4'-bis(hydroxy roethane unless otherwise stated. phenyl)-methane, and 3 percent by weight of 2,2'-bis The following examples illustrate the invention with (hydroxyphenyl)-methane. The melting point of the out limiting, however, the scope. mixture of isomers is about 100 to 110 degrees centi Example 1 grade, and the yield of the reaction approximately 70 percent. Such a mixture of isomers can, therefore, be : In a 1 liter three-necked, creased flask fitted with a con used directly in the polycondensation reaction, starting denser, a stirrer, a nitrogen inlet and a thermometer, 15.0 by dissolving the isomer mixture in water in the presence g. (0.075 mole) of bisphenol F are dissolved in 225 cm.3 of equivalent amounts of alkali hydroxides such as sodium of an aqueous soution of 7 g. of sodium hydroxide. To hydroxide or potassium hydroxide. When mixtures hav this mixture is added 0.6867 g. of benzyltrimethylammo ing a high proportion of the 2,2'-isomer are desired, the 2 5 nium chloride followed by 225 cm.3 of a solution of reaction of phenol and formaldehyde is carried out in the 15.2273 g (0.075 mole) of isophthaloyl chloride in presence of a basic catalyst such as zinc oxide. methylene chloride. The mixture is stirred at a rate of The metal diphenates are formed by dissolving the approximately 1,300 r.p.m.