Patent GB-1115737-A (GB)
Title: Polyurethane filaments and fibres
Inventor: WIEDEN HORST
IPC: C08G18/10
Filed: 1965-10-19
Abstract: A segmented polyurethane suitable for making elastic filaments is formed by reaction of a linear polyhydroxyl compound, having a melting point below 60 DEG  C., a molecular weight of 800 to 3200 and an OH number of 35-120 and having terminal hydroxyl groups with an excess of a diisocyanate, with a chain extending agent, if desired, the prepolymer so formed then being dissolved in a polar organic solvent at - 10 to + 100 DEG  C. and reacted with 2 to 50 mol. per cent of a further co-chain extending agent which is an organic compound containing two active hydrogen-containing groups and at least one acidic sulphur-containing group of the formula -SO3M-or <FORM:1115737/C3/1> in which M represents a hydrogen atom, an alkali metal atom or an ammonium group, said segmented polyurethane containing repeating units of the formula <FORM:1115737/C3/2> in which Y represent a bi-functional aliphatic or aromatic radical, X1 represents an oxygen atom and/or an -NH- group, X2 represents an oxygen atom or the group <FORM:1115737/C3/3> (in which R1 is a hydrogen atom or the group -SO3M- or an alkyl-SO3M group, the alkyl group of which has 2 to 8 carbon atoms) and R represents an arylene group substituted by at least one -SO3M group, a group of the formula <FORM:1115737/C3/4> a piperazine-N,N1-bis-alkylene group or a group of the formula <FORM:1115737/C3/5> in which R2 is an alkylene group having 2 to 8 carbon atoms, Z is an alkyl group or an alkyl -SO3M group, the alkyl group of which has 2 to 8 carbon atoms and n is an integer from 0 to 2, the radical M, whenever present, representing a hydrogen atom, an alkali metal atom or an ammonium group.  Preferably the linear polyhydroxyl compound is a polyester of an aliphatic diol and adipic acid.  Especially, the linear polyhydroxyl compound is a polytetramethylene ether diol.  Suitably, the diisocyanate is a symmetrical aromatic diisocyanate and the co-chain extending agent is preferably an alkali metal salt of an alkylene diamine-N-butyl-sulphonic acid, especially an alkali metal salt of ethylene diamine-N-butyl-sulphonic acid, or an alkali metal salt of a diamino aryldisulphonic acid, especially an alkali metal salt of 4,41-diamino diphenyl-2,21-disulphonic acid. The co-chain extending agent may also be an alkali metal salt of piperazine-bis-propylamino-N-butyl sulphonic acid. Alternatively, the co-chain extending agent may be an alkali metal salt of the g , g 1-bis-(aminopropyl)-N-methylamino-g -N-butyl sulphonic acid, or an alkali metal salt of 4,41-diamino-diphenyl-disulphonimide. Acidic sulphur groups SO(-)3 and/or -SO2N(-)SO2- may be present in the filament in an amount of 2 to 300 m.e.q. per kg. of elastomer. The polyurethane elastomer may also contain tertiary aliphatic nitrogen groups in an amount of 20 to 400 m.e.q. of tertiary N/Kg. of the polyurethane elastomer. A long list of suitable starting materials for polyester formation is given.  Specified solvents and further specified co-chain lengthening agents are given.  In a spinning method a prepolymer is prepared in the melt or in an organic solvent, from a high molecular weight substantially linear polyhydroxyl compound having a melting-point of below 60 DEG  C., an OH number of 35-120 and a molecular weight of 800 to 3200, an excess of a diisocyanate and if desired, a chain-extending agent, said NCO-prepolymer being dissolved in a polar organic solvent at - 10 DEG to + 100 DEG  C., and reacted with 2 to 50 mol. per cent calculated on the NCO groups of the NCO-prepolymer of a further chain-extending agent, containing two active hydrogen-containing groups, and, in addition, at least one acidic sulphur-containing group of the formula -SO3M- or of the formula <FORM:1115737/C3/6> which M represents a hydrogen atom, an alkali-metal atom or an ammonium group, and spinning the solution of polyurethane elastomer to form filaments.  A molar excess of up to 300% of diisocyanate may be reacted with the substantially linear polyhydroxyl compound. Where the further chain-extending agent contains the acidic sulphur-containing groups in the form of the lithium or trialkylammonium salt, the said agent may be added to the reaction mixture dissolved in a polar organic solvent.  The polar organic solvent may be dimethyl formamide and the chain-extending agent may be carbodihydrazide.  Examples 1-12 describe the preparation of spinning solutions.ALSO:In a method for the production of a segmented polyurethane, preparations of the following compounds are given:-In Example 2 piperazine-bis-propylamine-N -butyl sulphonic acid sodium salt is made by refluxing butanesultone with g :g 1-diamino-propyl-piperazine in isopropanol and neutralizing the resulting resinous piperazine-bis-propylamine-N-butyl-sulphonic acid with caustic soda. In Example 5, 1:6hexanediamine-3 -sulphonic acid sodium salt is made by hydrogenation of 1:4-dicyanobutane2-sulphonic acid sodium salt in the presence of Raney cobalt at 75-80 DEG  C. and 170 to 180 atmospheres after the addition of liquid ammonia.ALSO:An elastic filament having an essential linear structure of a segmented polyurethane formed by the method of the invention (see B5 Abridgment) may be dyed as described in the examples:- Example 1 describes the preparation of a spinning solution, and the dyeing of elastomer filaments produced therefrom by a one bath process with a 3% Astrazon Blue B dye bath (CT basic Blue 5; 42140) of pH = 4 at 100 DEG C for 60 minutes. Example 2 describes the preparation of a spinning solution followed by a dry spinning process, in which the spun filaments are stretched from 0 to 100% and then heat set for one hour at 130 DEG C in a nitrogen atmosphere to produce filaments which may be dyed with 2% Supraminrot GG (acid dyestuff) and with 2% Astrazon Blue BG (basic dyestuff).  The filaments may also be dyed with a 10% solution of the chrome dye Telonchromschwarz C.  Example 3 describes the preparation of a spinning solution which is painted on to glass plates and cut into threads after the evaporation of the solvent for one hour at 100 DEG C.  These threads may be dyed with Supraminrot (acid dyestuff), or with the after-chroming dyestuff Telonchromschwarz C or with 2% of Astrazon Blue BG (basic dyestuff). Example 4 is similar to Example 3.  Example 5 describes the preparation of a spinning solution from which filaments may be obtained which may be dyed with basic dyestuffs such as Astrazon Blue BG but not with acid dyestuffs.  Example 6 describes the preparation of a spinning solution which may be spun by the wet spinning process into water at 90 DEG C to yield elastomer filaments which may be dyed to deep colours both with the acid and basic dyestuffs previously specified.  Example 7 describes the preparation of a spinning solution which is cast to form films which are then cut up into filaments which may be dyed with Astrazon Blue or Telonchromschwarz. Example 8 describes the preparation of a spinning solution to yield filaments which may be dyed with the previously mentioned basic dyestuffs.  In Example 9 a spinning solution is prepared from which filaments may be obtained by wet spinning into an aqueous precipitation bath, said filaments being capable of dyeing with the acid or basic dyestuff previously specified.  Example 10 is similar to Example 9.  In Example 11 a spinning solution is prepared from which films are made by casting, the solvent being removed by heating for one hour at 100 DEG C.  These films may be cut to form filaments which may be dyed with 2% of C.I. Basic Blue 3; (C.I. No. 5; 1005). Example 12 describes the preparation of a spinning solution which is cast to form films which are then cut into filaments which may be dyed with 2% of the basic blue dye of Example 11.