Patent GB-917450-A (GB)
Title: Improvements in or relating to the manufacture of fibres, foils and coatings
IPC: D01F6/72
Filed: 1961-08-11
Abstract: A process for producing a solution suitable for the manufacture of fibres, foils and coatings, comprises mixing a substantially linear isocyanate-modified organic compound containing terminal NCO groups (which has been prepared by reacting an excess of an organic diisocyanate with an organic compound containing hydrogen atoms which are reactive with -NCO groups and having a molecular weight of from 700 to 5000) in an inert solvent with a dihydrazide having the general formula R-NH-NR1-A-(Z-A)n-NR1-NH-R wherein A is a CO, CS or CS2 group; R and R1 each represent a hydrogen atom, an alkyl radical or an aryl radical, with the proviso that at least twice in the molecule R and R1 represent a hydrogen atom; Z is an alkylene radical, the chain of which may be interrupted by one or more heteroatoms or an arylene radical, an aralkylene radical, an NH, -NH-NH, O-Y-O or NH-Y-NH group wherein Y in the last two formulae is a divalent organic radical, and n is 0 or 1.  The isocyanate-modified compound may be one obtained by reacting an excess of an organic diisocyanate with (a) a hydroxyl polyester prepared by reacting a dihydric alcohol with a dicarboxylic acid, (b) a polyhydric polyalkylene ether, (c) a polyester amide, (d) a polyhydricpolythioether, (e) a polycarbonate or (f) a polyacetal. The formation of the isocyanate-modified compound can be effected in solution in, for example, methylene chloride, acetone or benzene.  Up to 5% of a trifunctional alcohol can be present at this stage.  The product, before reaction with the dihydrazide, can be dissolved in dimethyl formamide, dimethyl acetamide, dimethyl propionamide, tetramethylene sulphone, N-methylpyrrolidone, dimethyl sulphoxide or hecamethyl phosphorous amide; and the solution may be blended with other solvents.  As compounds of the general formula above there are listed dihydrazides, disemicarbazides, dithiodisemicarbazides, bis hydrazine carboxylic acid esters of glycols, N,N1-diaminobiuret and hydrozodicarboxylic acid dihydrazide.  A monohydrazide (e.g. 0, to 4%) may be reacted at the same time.  In examples (1) a polyether isocyanate is prepared by reacting polytetramethylene glycol ether and 4,41-diphenylmethane diisocyanate and is reacted with about an equimolar quantity of carbodihydrazide.  The product can be spun into filaments and cast into films; (2) a polyester isocyanate obtained from a polyester of butane-1,4-diol, hexane-1,6-diol and adipic acid, reacted with 0,5 mol. toluene diisocyanate and then with excess 4,41-diphenyl dimethyl methane diisocyanate is reacted with carbodihydrazide.  In other examples the isocyanate-modified compound is prepared from ethylene glycol/adipic acid polyester, a polyester-urethane from hexanediol/adipic acid polyester and toluene diisocyanate, a polyacetal from 50 mol. per cent 1,6-hexanediol, 50 mol. per cent methylhexanediol-1,6 and formaldehyde, and a polyester acetal from an adipic acid bis-hydroxyhexyl ester and formaldehyde. Other compounds of the above general formula used are adipic acid dihydrazide, hexamethylene bis-semicarbazide, 1,4-butanediol-bis-hydrazine carboxylic acid ester, 1,4-phenylene-bis ethyl ether carbazine acid ester, ethylene-bis-semicarbazide, N,N1-piperazine dicarbonic acid hydrazide and succinnic acid dihydrazide.  In Example (6) a continuous process is employed in which a solution of diisocyanate treated ethylene glycol/adipic acid polyester in chlorobenzene is passed into a mixer into which a solution of carbodihydrazide in water and dimethyl formamide is introduced through a nozzle and a pigment paste containing titanium dioxide is introduced through another nozzle.  The solution of product can be spun into hot air or hot water or can be cast on to glass plates to give elastic foils.  Specifications 594,805, 772,627, 798,209, 808,488, 819,384 and 840,097 are referred to.ALSO:1,6-Hexamethylene-bis-semicarbazide is obtained by the catalytic reduction of the carbobenzoxy compound prepared from carbobenzoxyhydrazine and 1,6-hexamethylene diisocyanate. 1,4-Butanediol-bis-hydrazine carboxylic ester is prepared by reacting 1,4-butanediol-bis-chlorocarbonic acid ester with excess hydrazine hydrate.  Carbobenzoxyhydrazine reacted with 1,4-phenylene-bis-ethyl ether chlorocarbonic acid ester gives di-carbobenzoxy-1,4-phenylene-bis-ethyl ether carbazine acid ester, catalytic reduction of which gives 1,4-phenylene-bis-ethyl ether carbazine acid ester.  Ethylene-bis-semicarbazide is prepared by reacting ethylene-bis-carbamic acid phenyl ester and hydrazine hydrate at 60 DEG C.  N,N1-piperazine-dicarbonic acid dihydrazide is obtained by heating the corresponding diphenyl ester with hydrazine hydrate at 60 DEG C.  The compounds are used to react with polyisocyanates in the preparation of polymers.