Patent GB-675169-A (GB)
Title: Improvements in synthetic resins obtained by condensation of polyhydric phenol and halogenhydrins
IPC: C08G65/28
Filed: 1947-12-15
Abstract: Complex resinous epoxy compounds are prepared by reacting a dihydric phenol with more than one but less than two molar proportions of epichlorhydrin or glycerolchlorhydrin in the presence of alkali to form complex intermediate compounds, which are washed free from salts and then reacted further with a dihydric phenol.  Preferably 1.2-1.5 mols. chlorhydrin are used per mol. phenol.  Dihydric phenols specified are bis-phenol, bis-(4-hydroxy phenyl) sulphone, resorcinol, hydroquinone, p,p1-dihydroxybenzophenone, p,p1-dihydroxy diphenyl, p,p1-dihydroxy dibenzyl, 2,21-dihydroxy-1,11-dinaphthyl methane, 1,5-dihydroxynaphthalene.  In the second step traces of catalysts, e.g. sodium hydroxide or acetate, are preferably added. The products obtained are, when not too highly polymerized, soluble in acetone, methyl ethyl ketone, diacetone alcohol and cyclohexane and in solution may be applied as varnishes, impregnants, films and filaments; with further heating in presence of catalysts, e.g. boron trifluoride, they are converted to the infusible state. When thus treated they tend to expand a feature valuable for moulding purposes. When containing hydroxyl or epoxy groups they may be esterified.  The quantity of phenol to be added in the final step may be calculated by determining the epoxide equivalent of the intermediate product by heating 1 gm. with excess of pyridine containing pyridine hydrochloride and titrating the excess hydrochloride with 0.1 N. NaOH.  A typical method of obtaining the intermediate product using 3 molar proportions of bis-phenol to 4 mols. epichlorhydrin and 25 per cent excess NaOH comprises dissolving 307.5 lbs. bis-phenol, 166.3 lbs. epichlorhydrin and 54 lbs. of the NaOH in 600 lbs. water in an open kettle and allowing the temperature to rise to 65 DEG  C. 18 lbs. more NaOH were added and the temperature brought to 79 DEG  C., whereupon the remaining 24 lbs. NaOH were added and the temperature brought to 90-100 DEG  C. for an hour.  The aqueous layer was separated and the product washed with boiling water containing acetic acid and dried at 150 DEG  C.  In examples: (1) 591 gs. of the product obtained by reacting bis-phenol and epichlorhydrin in molar proportions of 5 : 7 were reacted with 42.4 parts bis-phenol; (2) 730 parts of the resin obtained from 3 mols. bis-phenol and 4 mols. epichlorhydrin were reacted with 57 mols. bis-phenol; (3) 33 parts hydroquinone were reacted with the reaction product of bisphenol and epichlorhydrin in molar ratio 4 : 5; (4) the proportions are 5 : 6 and the product is reacted with bis-phenol.  Specification 675,171 is referred to.  The Specification as open to inspection under Sect. 91 refers to polyhydric phenols other than dihydric, e.g. phthloroglucinol, o,p,o1,p1-tetrahydroxy diphenyl dimethyl methane; to halohydrins other than those of glycerol and epichlorhydrin, e.g. bis-(3-chloro-2-hydroxy propyl) ether, 1,4 - dichloro-, 2,3-dihydroxy-butane, 2-methyl-, 2-hydroxy-, 1,3-dichloropropane, bis - (3-chloro-, 2-methyl-, 2-hydroxy - propyl) ether, chlorhydrins derived from aliphatic olefines, mannitol, sorbitol and like alcohols.  It also includes an example (Example (II), Cancelled) in which 912 parts of bis-phenol are reacted with 740 parts epichlorhydrin in presence of 330 parts NaOH in 2500 parts water to obtain a resin which was further reacted with bis-phenol in the proportions of 57 parts bis-phenol to 325 parts resin. This subject-matter does not appear in the Specification as accepted.