3,461,106 United States Patent Office Patented Aug. 12, 1969 1. 2 have insufficient fastness, frequently accompanied by 3,461,106 PGLYURETHANE FBERS insufficient absorption rates and depth of colour of the Harald Oertel and Heinrich Rinke, Leverkusen, Wilhelm dyeings, factors which also have a negative effect on the Thoma, Cologne-Flittard, and Friedrich-Karl Rosen fastness of such dyeings to abrasion. Further, the over dahl, Leverkusen-Schlebusch, Germany, assignors to dyeing properties are in many cases inadequate owing Farbenfabriken Bayer Aktiengeseischaft, Leverkusen, to the poor wash fastness of the dyeings. If, however, Germany, a corporation of Germany polyurethane elastomer fibres are to be widely used No Drawing. Fied May 21, 1965, Ser. No. 457,800 for textile purposes, the obtaining of deep and fast dye Claims priority, application Germany, May 23, 1964, ings is essential. This applies especially to the use of F 42,970 important groups of dyes such as acid dyes, metal com int. C. C08g 22/04, 22/06 O plex dyes or chrome dyes with which fast dyeings in U.S. C. 260-75 11 Claims deep colour tones can be obtained e.g. on polyamides which are used preferentially in conjunction with elastic polyurethane threads. The stability of polyurethane ABSTRACT OF THE DISCLOSURE 5 elastomer threads and foils to discolouration in light and Segmented polyurethane elastomers having improved to yellowing under the effect of atmospheric waste gases dyeability containing a repeating unit and having at least (especially nitrous gases and waste gases of combustion) one carboxylic acid hydrazide grouping and at least one still leaves room for improvement. The dyeability of tertiary amino group. The polyurethane elastomers being these polyurethane elastomers, especially those used for prepared by reacting a substantially linear NCO ter 20 the production of highly elastic filaments or foils, minated prepolymer with a chain extending agent contain especially with dyes from the group of acid dyes, metal ing at least one carboxylic acid hydrazide group and at complex dyes or after-chroming dyes, which preferably least one tertiary amino group alone or in mixture with contain acid groups in the dye, is markedly improved. In other chain extending agents, said reacting being effected the preparation of polyurethane elastomers by the diiso in an inert polar organic solvent. Elastic fibers are pre 25 cyanate polyaddition process from high molecular weight, pared from the obtained polyurethane elastomer solution polyurethane elastomers and filaments and fibres thereof by known spinning processes. having a high elastic recovery, substantially linear poly hydroxy compounds, polyisocyanates and chain lengthen ing agents having reactive hydrogen atoms by reaction in This invention relates to novel polyurethane elastomers 30 highly polar organic solvents, the chain lengthening agents having a segmented structure and to a process for prepar used are compounds which contain at least one of the ing these elastomers. Furthermore this invention relates reactive hydrogen atoms in the form of an to fibres, filaments and foils prepared from these polyure -X-CO-NHNH thane elastomers. 35 The preparation of polyurethane elastomers by the group (X=hydrocarbon or O, NH or N-alkyl) and in diisocyanate polyaddition process from high molecular addition contain one or more tertiary amino groups and Weight, Substantially linear polyhydroxy compounds, poly in which all the carbon atoms directly attached to the isocyanates and chain lengthening agents which have tertiary nitrogen atom are aliphatic carbon atoms. These reactive hydrogen atoms by reaction in highly polar or 40 polyurethane elastomers contain 20 to 1000 milliequiva ganic solvents is already known. In particular, polyure lents of tertiary nitrogen-resulting from the chain ex thane elastomers prepared in highly polar organic solvents tending agent-per kg. elastomer. In particular, these are also used for forming filaments and fibres which are chain extending agents to be used according to the inven used for many different purposes in the textile industry, tion can also be added to the known chain lengthening especially in the corsetry and underwear industry, for 45 agents with reactive hydrogen atoms in quantities such bathing wear, elastic garments or stockings, if desired that the finished polyurethane elastomers contain 20 to as core spun elastomer yarns spun round with filaments 400 millieduivalents of tertiary nitrogen per kg. of elasto or staple fibre yarns or as staple fibre admixture to non mer substance. The quantity of hydrazide compound to be elastic fibres for the purpose of improving the wearing used according to the invention usually sufficient for in qualities of fabrics which are not in themselves highly 50 creasing the dyeability is generally less than 50 mol per elastic. Elastic polyurethane filaments have numerous advan cent and frequently even less than 30 mol percent and tages over rubber filaments; thus they can be obtained especially less than 15 mol percent of the total quantity of in practically any degree of fineness for textile purposes, chain lengthening agents required for the reaction. The they have a higher tensile strength and abrasion resistance 55 modification in the molecular construction which results and in many cases higher resilience, they are largely has practically no effect on the mechanical or elastic resistant to cosmetic oils and solvents used in dry clean properties of the elastomer substance. On the other hand, ing and they have a high resistance to oxidation and in addition to the dyeability numerous other properties of ozone. Furthermore, in contrast to rubber filaments, the elastomers and their solutions are highly improved. polyurethane elastomer threads can be dyed relatively These polyurethane elastomers having an essentially easily with certain classes of dyestuffs, e.g. dispersion 60 linear segmented structure, consist of the reaction product dyes. of an NCO-preadduct from a diisocyanate and an essen Owing to the special structure of polyurethane elas tially linear polyhydroxy compound having terminal hy tomer filaments, which consist at least up to about 70% droxyl groups and a molecular weight from about 500 to of amorphous constituents (components of the high 65 about 5000 with an organic nitrogen-containing chain molecular weight polyhydroxy compounds), these elas extender compound, said polyurethane elastomer contain tomer threads take up certain dyestuffs (e.g. dispersion ing a repeating unit having at least one tertiary nitrogen dyes) relatively easily but these dyes can very easily diffuse out of the elastomer substance again, e.g. in wash atom of the formula ing, so that such dyeings are usually of poor (wet) fast ness. The same applies to dyeings obtained with so-called 70 acid dyes, chrome dyes or after-chroming dyes, which also 3,461,106 3 4. wherein A is a member of the group consisting of the -NH-CO-NH-; at least some of said units being O-group, the DNH-group and the group connected by urethane linkages being attached to the residues of the linear polyhydroxy compound; said repeat -X-CO-NH.NH ing unit being present in an amount according to 20 to X is a member of the group consisting of oxygen, the 5 400 millieduivalents of tertiary nitrogen per kg. of said NH-group and the DN-R group; Y is a bifunctional polyurethane elastomer. radical consisting of the piperazine radical, an alkyl Due to the slight modification in the molecular con piperazine radical, the radical struction, the solubility is highly improved and the stability of the elastomer solutions increased. Such a -N- 0 modification is an advantage, especially when very high melting polyurethane elastomers (M.P. above 250) are to be built up with chain extending agents such as cyclo - E aliphatic and aromatic diamines, especially 1:4-diamino cyclohexane and p-xylylenediamine, in which those chain R NY. 5 segments which contain urea groups generally cause and the radical great reduction in the solubility with the result that the solutions are not stable or immediately become pasty so -- C-R1-C Hi-N- that they cannot be subjected to shaping processes. R R It is noteworthy that due to the slight modification by 20 the process according to the invention, much more stable R is lower alkyl, R1 a member of the group consisting solutions can be obtained which are fluid for a longer of phenylene and cyclohexylene, Z an aromatic bivalent period and can therefore readily be spun. radical and n an integer from 1 to 6; said repeating unit By suitable choice of the proportions of modifying being present in an amount of according 20 to 1000 hydrazide compounds it is possible to obtain polyurethane millieduivalents of tertiary nitrogen per kg. of said poly 25 urethane elastomer. fibres which readily permit at tone in tone dyeing with Especially improved properties are shown by a poly the surrounding yarns or with other fabric components, urethane elastomer having an essentially linear segmented which makes it possible to use such elastomer filaments structure, consisting of the reaction product of a NCO for many different purposes in the textile industry. preadduct from a dissocyanate and an essentially linear In addition, formed articles such as filaments or foils polyhydroxy compound having terminal hydroxyl groups 30 obtained from the polyurethane elastomers according to the invention have also increased resistance to yellowing and a molecular weight from about 500 to about 5000 on prolonged standing in air or when exposed to the with an organic nitrogen-containing chain extender com action of nitric oxides or waste gases of combustion or pound, said polyurethane elastomer containing a repeat to light, especially to UV radiation. Much lighter coloured ing unit (a) having at least one tertiary nitrogen atom of 35 threads and foils are obtained also in dry spinning or in the formula casting of the elastomer solutions. This applies especially to the relatively easily discoloured polyurethane composi tions obtained by chain lengthening with aromatic diamines or water.