GB733624A - New synthetic resins derived from linear aliphatic polyethers and bifunctional isocyanates and rubber-like materials derived therefrom - Google Patents

Abstract

Synthetic resins are produced by reacting preferably at 120-160 DEG C., an aliphatic linear polyether with terminal hydroxyl groups and an average molecular weight greater than 1000 with an excess of a bifunctional isocyanate under substantially anhydrous conditions. Some of the suitable isocyanates mentioned are hexamethylene di-isocyanate 2-nitrodiphenylene-4 - 41 - di - isocyanate, 2 - nitrodiphenylmethane - 4,41 - di - isocyanate, naphthylene-1,4 - di - isocyanate, chrysene - 2,8 - di - isocyanate, tolylene, 4,41 - di - isocyanate, diphenylene - 4,41 - di - isocyanate and 4,41 - cyclohexyl di-isocyanate. Suitable polyethers are obtained by polymerization or copolymerization of ethylene oxide, isopropylene oxide, trimethylene oxide, a -methyltrimethylene oxide, 3,31-dimethyl trimethylene oxide, tetrahydrofurane, 1,3-dioxane or dioxolane. If the terminal groups are other than hydroxyl, e.g. chloro, they must be converted to hydroxyl, e.g. by heating with dilute alkali. The reaction mixture of di-isocyanate and polyether is made neutral or alkaline, e.g. by addition of a base such as triethylamine. the polyether is preferably dried, e.g. by heating in dry inert gas. If the molecular weight of the polyether is below 5000, the excess of di-isocyanate is relatively small to increase the chain length of the polymer. With polyethers of mol. weight above 5000, a large excess of di-isocyanate is used. The products have the general formula <FORM:0733624/IV (a)/1> in which R is the same or different aliphatic hydrocarbon radicals, the X's are divalent organic radical and a and b are integers, a being such that HO(R.O)oH has a mol. weight of at least 1000 and b such that the polymer has a mol. weight of at p least 2000. Rubber-like materials may be produced by heating these synthetic resins in presence of a basic catalyst, e.g. sodium methoxide or ethoxide; calcium or barium oxide or hydroxide; beryllium, lithium or sodium hydroxide; tri-methyl-, ethyl-, propyl-, butyl-, amyl- or benzyl-amine or dimethylaniline. The catalyst is mixed with the polyether before or after reaction with the di-isocyanate, by stirring or on a mill or Banbury mixer. Colouring materials may be added. Rubber-like materials may also be produced by modifying the resins with water, steam, ammonia or a compound with two groups capable of reacting with isocyanate groups. If the mixture is fluid reaction may be performed in a stirred mixer, otherwise on rolls or in a Banbury mixer. With water reaction may be at below 100 DEG , e.g. 80 DEG C., but preferred reaction temperatures are 120-160 DEG C. followed by mastication at 103-140 DEG C. Water may be added as a hydrated salt, e.g. sodium sulphate decahydrate. With diamines, dicarboxylic acids or amino acids cooling is necessary to permit mixing before reaction at higher temperature. Steam or ammonia as modifying agents may be blown on to the surface of the resin. Suitable bifunctional reagents are ethylene glycols; 1,3-propane diol; 1,4-butane diol; ethylene diamine; tri- or tetra-methylene diamine; m-phenylene diamine; naphthylene diamines; tolylene 2,4 - diamine; aminobenzylaniline; aminodiphenylamine; 2 - aminoethyl alcohol, 2 - amino - 1 - naphthol; m - aminophenol; glycollic acid; a - hydroxypropionic acid; amino acetic acid; and aminobenzoic acid. The products of the invention may also be converted to rubber-like products by reaction with polyhydroxy compounds, e.g. glycerol, pentaerythritol, trihydroxy tertiary butane, trimethylol propane, trimethylol ethane, 1,2,4-butane triol or Novolak resins of low molecular weight. The polyhydric compound may be mixed with the synthetic resin while it is still hot from its production or they may be mixed cold for conversion to the rubber-like state later. Conventional additives may be incorporated at any stage before conversion. The compositions ready for conversion to rubber-like state may be cast, moulded, or extruded as ribbon, film, fibres or filaments, or may be applied as coatings or impregnants. In examples tetrahydrofurane is polymerized, dried and reacted with various di-isocyanates. The products were (1) moulded after addition of water; (2) mixed to a crepe on a roll mill with tolylene diamine; (3) formed to a sheet by reaction with (a) triethylamine or (b) 1.4 butane diol; (4) moulded after admixture with sodium methoxide; (5) formed to a crepe on a roll mill with glycerol or 1,2,4-butane triol. Other examples are similar. In two of the examples the initial polyether was polytrimethylene oxide or poly-a -methyl trimethylene oxide.