IE43431B1 - Segmented self cross-linkable polyurethane elastomers - Google Patents

Description

This invention relates to shaped segmented self cross-linkable and sell cross-linked polyurethane products and to a process for their production.

So-called 'Segmented polyurethane elastomers which have a substantially linear structure have recently gained considerable importance. They are preferahly used in the form of their solutions in highly polar solvents and have become important in the spinning of polyurethane elastomer filaments; coating textiles; manufacturing foils and producing microporous foils or synthetic leather products.

The very special demands made of such materials and especially of elastomer filaments can only he satisfied with suitable choice of the starting materials and reaction conditions. The segmented structure of these substantially linear polyurethanes plays a considerable role, since some qualities such as the stretchability, for example, depends mainly on the longer chain soft segments (dihydroxy compounds) while the softening and melting range, the resistance to tension at elevated temperatures or in hot water, the modulus and the strength depend to a large extent on the so-called hard segments composed of diisocyanate and chain lengthening agents (see Chemiker-Zeitung 98 (1974), pages 344 - 353)« Essential factors in determining the elastomer properties are the symmetry of the hard segments and optimum physical aggregation via hydrogen bonds (hydrogen bridge cross-linkages) between a plurality of individual hard segments.

This so-called physical cross-linking through hydrogen bonds can easily he broken down, for example hy means of highly polar solvents such as dimethylformamide which have a solvating effect on the hard segment. s' Moreover, the strength of the bond decreases rapidly with increasing temperature.

There have therefore been numerous attempts to improve the properties of elastomers by additional chemical crosslinking, for example hy the addition of polyisocyanates, polyethyleneimine derivatives, epoxides or poly.formaldehyde derivatives such as polymethylol or polymethylolether derivatives. It has been found that subsequent chemical cross-linking of the polyurethanes can be achieved by addition of the above compounds and has fcho added effect of rendering the polyurethanes insoluble and, in some cases, also improving certain elastic properties but other properties which are in practice more important, particularly thermal and hydrothermal properties, are deleteriously affected.

Particularly important properties for practical purposes include, for example, the behaviour of the filaments under tension or stretching in hot water, for example under the conditions employed for dyeing and finishing the filaments. Another important property is the so-called flow range of the fjlaments under a given tension at elevated temperatures, for example under the conditions employed for heat fixing, or the behaviour of the filaments in elastic knitted fabrics under the conditions of so-called thermal deformation in which the filaments are highly stretched at high temperatures.

This new technique which is used, for example, for shaping cups of brassieres made of knitted polyamide-Elasthane fabrics instead of sewing them (Elasthane is a Registered Trade Mark)f makes particularly stringent demands on the thermal behaviour of elastomer filaments.

It is an object of the present invention to provide improved polyurethane elastomers or filaments which (a) can be chemically cross-linked or are self-cross-linkable (b) contain the cross-linking group in a particular form so - 3 43431 that it has a much more advantageous influence on the thermal and hydrothermal properties than can be achieved by the addition of cross-linking agents in accordance With the known art (c) have improved capacity for deformation by heat, and (d) have improved resistance to hydrolysis, improved solvent resistance, improved resistance to thermal degradation and if required may also have improved surface bonding and improved resistance to yellowing.

The cross-linking reactions with urethane and, preferably, urea segments should be easily released by heat and should not require the presence of specific groups, e.g.tertiary amines, and the cross-linking effects should be achieved (e.g. insolubility of the product) with smaller quantities of cross-linking groups than are required when external crosslinking agents are used.

It is a further object of this invention to provide stable solutions of self-cross-linkable polyurethanes.

This invention relates to a process tor the manufacture of a shaped polyurethane product: which is selfcross-linkable with methylolether groups or cross-linked with methylol ether groups, in which process a substantially linear isocyanate prepolymer obtained from a dihydroxy compound with excess organic diisocyanate, which prepolymer has been modified by the incorporation of a monomethylol ether diol of the formula HO-R-N-R-OH ψΗ)χ (I) O=CNH-CH2-OR' in which R represents a straight or branched chain alkylene group; R' represents an alkyl group and x represents 0 or 1, is reacted in a solvent with a chain-lengthening agent and the shaped product is formed from the resulting solution and cross-linked during or after the shaping process, where a cross-linked product is to be manufactured.

More specifically, this invention relates to a process for the manufacture of a polyurethane product in the form of a filament, foil or coating which is cross-linked with methylol ether group or self-cross-linkable in which process a substantially linear isocyanate prepolymer obtained from a dihydroxy compound having a molecular weight of 600 to 6,000 with excess quantities of an organic diisocyanate, optionally also using a low molecular weight diol which has been modified by incorporating a mono-methyl ether diol of the formula HO-R-N-R-OH I (NH) I O=CNH-CH2-OR' (I) in which R represents a straight or branched chain alkylene group having up to 12 carbon atoms, preferably an ethylene or propylene group, R' represents an alkyl group, preferably one having up to 4 carbon atoms, more preferably a methyl group, and x represents 0 or 1, preferably 1, - 5 43431 into the isocyanate prepolymer in quantities of from 0.1 to 10% by weight, preferably 0.25 to 5.0% by weight based on the solids content of the isocyanate prepolymer, is reacted in a solvent in a chain-lengthening reaction with a low molecular weight compound such as a diol or water, or preferably a compound which contains NH-active end groups and has a molecular weight of 32 to 400, such as a diamine, an amino, alcohol, a dihydrazide compound or hydrazine compound, and forming the shaped product from the resulting solution and cross-linking by heating during or after the shaping process.

The invention also relates to shaped polyurethane products which can be self-cross-linked by methylolethers and are obtained by chain lengthening a substantially linear isocyanate prepolymer obtained from a dihydroxy compound having a molecular weight of from 600 to 6000 and excess quantities of an organic diisocyanate with the optional additon of low molecular weight diols in a solvent with a low molecular weight compound such as a diol or water but preferably with a compound having a molecular weight of from 32 to 400 which contains NH-active end groups, such as a diamine, an amino alcohol dihydrazide compound or hydrazine and shaping the resulting substance said polyurethane - 6 4343 I products containing monomethylolether diols of the formula no _ r - n - 11 - oil t (Nil) I λ = CNH - CII„ - OR' (I) ill which It represents a straight, or branched chain alkylene group having up to 12 carbon atoms, preferably an ethylene or propylene group.

It' represents an alkyl group preferably having up to 4 10 carbon atoms, preferably a methyl group, and x represents 0 or 1, preferably x = 1, built into the isocyanate prepolymer in quantities of from o.l to 10% by weight, preferably 0.25 to 5.0% by weight, based on the solid content of the isocyanate prepolymer. Π The invention also relates to polyurethane products in tins form of filaments, foils or coatings which have been self cross-linked by inethylolethers groups, produced by chain lengthening substantially linear isocyanate prepolymer obtained from a dihydroxy compound having a molecular weight of from 600 to 6000 and excess quantity of organic diisocyanates, optionally with the addition of low molecular weight diols, in a solvent with low molecular weight compound such as a diol or water but preferably with a compound containing N-H-active end groups and having a molecular weight of from 32 to 400, such as diamine, an amino alcohol, a dihydrazide compound or hydrazine and converting the solution into shaped products, said polyurethane containing monomethylolether diols of the formula HO - Ii - N - R - OH I (Nil) I x = CNH - CH» - OR' wherein R represents a straight or branched chain alkylene group having up to 12 carhon atoms.

R' represents an alkyl group having up to 4 carhon atoms and x = 0 or 1, preferably x = 1, built into the isocyanate prepolymer in quantities of from about 0.1 to 10% hy weight, preferahly 0.23 to 5.0% hy weight based an the solid content of the isocyanate prepolymer and said cross-linking being released by heat after the solution has been converted into shaped products.

The marked improvement in the properties of shaped products produced hy the process according to the invention may possibly he explained by the fact that cross-linking takes place between two linear segmented polyurethane molecule chains through branching or cross-linking points in different regions of the molecules. Thus one potential cross-linking point is already incorporated in a controllable form as monomethyl ether diol (i) in the so-called soft segment of the so-called isocyanate prepolymer (see scheme of formulae A) while the other cross-linking point is obtained from the reaction of the methoxymethyl group with, in most cases, the so-called urea hard segment. A cross-linking reaction is therefore achieved hy preferential reaction with only one hard segment.

The reaction of the methylolether group with urethane groups within the soft segment which may take place to a minor extent results exclusively in a cross-linking between soft segments, which is in itself desirable.

The conventional addition of himethylol or polymethylol ether compounds, on the other hand, leads to chemical reactions in two or more different hard segments. Not only does this lead to a less advantageous statistical distribution of the cross-linking points hut the repeated chemical substitution in several hard segments is also undesirable.

The latter is liable to interfere with the physical - 8 4 3 4 3 i cross-linking via hydrogen bridge bonds to such an extent l.iiut the number of pliysicul cross-linking bonds is reduced otil, of proportion to tlie increase in the number of chemical cross-1 inking bonds. Tliis results in a deterioration in numerous properties.

The controlled construction of self-eross-linkable segmented polyurea polyurethane molecules according to the invention, with incorporation of monomethylolether diols in the soft segment, is also superior to an incorporation of methyiolether derivatives in the hard segment or an addition of polymers, e.g. of polyurethanes of diisocyanate and monomethyloletherdiol (i) as can he seen from the comparison examples.

Incorporation of the mono-methylether diols (i) into the soft segment of the isocyanate prepoiymers can he carried out during the usual method of preparation of the prepolymer for example by using (i) in the reaction of the higher molecular weight dihydroxy compounds liO-G-OH (Cl = radical of dihydroxy compound) with excess quantities of diisocyanates OCN-D-NCO (D = radical of diisoeyanate) resulting in formation of the isocyanate prepolymer having the idealised structure shown in the scheme of formulae A. - 9 J 3 4 3 1 O O Ϊ P I o o s o •r4 P Ol « of prepolymer formation with incorporation of the monomethylolether diol I 0) r-1 0 rt fc 0 P 0 a ω o •rt P fc -P CQ CD r-l ft s fc o G fc O «Η fc s >9 rt O ft fc ft I «λ I >ei o o V « H rt o rt *d + W to w °· 13 o o fOJ’rt W rt O 1 ->♦ σ ?· o I a o o o fc o 1 1 +2 r-i bD (So.hh S£.S I fc Ό 0 fc xs too o bOrt φ »5!§ OP o co 53 a I 0 P s I o fej o o « O«H N\ w o o CM -g >e< s a rt O ft fc ft P a h υ o n •rt rd •rt o a P p fc o fc O rt P •rt & fi o p •rt > fc P ·§ ei £1 - 10 o CM CM ? I a p a ω ω fc •rt fc P & g rt fc •rt P o & o •rt P P to fc •rl fc P P ω fc tO fc •rl fc P P ω α rt fc •rt P o O rt OP •rt fc Ό 0 0 hO fc 0 I o o I tl K\ Ol - -g ei P fc O F r*\ fc fc O I § fi o ft Ό ® •P S CQ 3 4 3 1 The modified isocyanate prepolymer which is capable of cross-linking behaves in practice like an unmodified isocyanate prepolymer. In a chain lengthening reaction with diamines, for example, it fo»-ms the typical hard segment -Nlf-CO-NlI-y-NH-CO-MIwhii-h, hy its interaction with a large number of adjacent hard segments via hydrogen bonds, forms blocks of hard segments which are physically cross-linked witli each other and thereby produces the typical elastic properties in the polymers.

Tliis hard segment is the preferred point of action for chemical cross-linking with the methylolether group.

The monomethyloletherdiols HSed which are capable of being built into the molecule are those of the formula HO-R-N-H-OH I (NH) I (I) C0-NH-CH2-0~R' in which It represents a straight or branched chain group having up to 12 carbon atoms, but preferably a ~CIi,,-CHo- or -CIIg-CH- group, “ “ I CII3 It' represents an alkyl group having up to 4 carbon atoms, e.g. a methyl, ethyl, propyl, isopropyl or butyl group, and x = 0 or 1, preferably x = 1.

The compounds are best obtained from asymmetric N,Ndihydroxyalkyl hydrazines or N,N-dihydroxyalkylamines by reaction with alkoxymethyl isocyanates or its reactive derivatives, if indicated in inert solvents. The preferred components are bis-(p-hydroxyethyl)- or bis-(p-hydroxypropyl)amine or -hydrazine and methoxymethylisocyanate.

Semicarbazide derivatives (formula I, x = 1) are particularly suitable compounds. They can be incorporated directly in------------------- 11 31 the prepolymer, provide a certain additional stability to discoloration on exposure to light and give rise to particularly advantageous thermal properties and maximum improvement in the characteristic thermal property of heat tearing time., Suitable monomethylolether diols which can be incorpora ted in the molecule are, for example, semicarbazide derivatives I (x = l) of the following formula (1) HO-R-N-R-OH '(2) NH ' W CO - NH - CHgO - H’ (for numbering of the N-atoms see formula), in particular the following: 1.1- Bis-(2-hydroxyethyl-)-4-methoxymethyl-semicarbazide; 1.1- bis-(2-hydroxyethyl-)-4-ethoxymethyl-semicarbazide; 1.1- bis-(2-hydroxyethyl-)-4-propoxymethyl-semicarbazide; 1.1- bis-(2-hydroxyethyl-)-4-butoxymethyl-semicarbazide; 1.1- bis-(2-hydroxyethyl-)4-pentoxymethyl-semicarbazide; 1.1- bis-(2-hydroxyethy1-)-4-octyloxymethyl-semicarbazide; 1.1- bis-(2-hydroxyethyl-)-4-decyloxymethyl-semicarbazide; 1.1- bis-(2-hydroxypropyl-)-4-methoxymethyl-semicarbazide; 1.1- bis-(2-hydroxybutyl-)-4-methoxymethyl-semicarbazide; 1.1- bis-(1-methy1-2-hydroxy-propyl-)-4-methoxymethyl-semicarbazide; 1.1- bis(2-methyl-2-hydroxy-propyl-)-4-methoxymethyl-semioarbazide; 1.1- bis-(l,l-dimethyl-2-hydroxy-ethyl-)-4-methoxymethylsemicarbazide; 1-(2-hydroxye thyl)-1-(2-hydroxypropyl-)-4-methoxymethy1semicarbazide; 1-(2-hydroxyethyl)-1-(2-hydroxybutyl-)-4-methoxymethylsemicarbazide; 1.1- bis-(2-hydroxypropyl-)-4-ethoxymethyl-semicarbazide and I,l-bis-(2-hydroxybutyl-)-4-ethoxymethyl-semiearbazide.

Other suitable derivatives are the urea derivatives I (x = ()), in particular the following: N-Methoxymethy1-N',N’-bi s-(2-hydroxye thyl-)-urea; N-e thoxymethyl-N’,N'-bis-(2-hydroxyethyl-)-urea; N-propoxymethyl-Ν' ,N '-bis-(2-hydrc: ycthyl--)-ure<-·; N-n-butoxymethy1-N',N'-hi s-(2-hydroxyethyl-)-urea; N-n-hexyloxymethyl-N’,Ν'-bis-(2-hydroxyethyl-)~urea; N-n-dodeeyloxymethyl-N',N'-bis-(2-hydroxyethyl-)-urea; N-methoxymethyl-N N-methoxymethyl-N N-methoxymethyl-N N-methoxymethyl-N N-me thoxymethyl-N N-methoxymethyl-N N-methoxymethyl-N N-methoxyme thyl-N N-methoxymetliyl-N N-methoxymethyl-N N-ethoxymethyl-N' N-ethoxymethyl-N' ,N1-bis-(2-hydroxypropyl-)-urea; ,N'-bi s-(2-hydroxybutyl)-urea; ,N'-bis-(l-methyl-2-hydroxy-propyl-)urea; ,N *-bi s-(2-methyl-2-hydroxy-propyl)-urea; ,N'-bis-(l,l-dimethyl-2-hydroxy-ethyl-)-urea; '-bi s-(2-hydroxy-2-phenyl-ethyl-)-urea; ,N'-bi s—(2-hydroxy-2-phenoxy-propyl-)-urea; ,N'-bi s-(2-hydroxy-3-allyloxy-propyl-)-urea; -2-hydroxyethyl-N'-2-hydroxypropyl-urea; 2-hydroxyethyl-N'-2-hydroxybutyl-urea; N'-b i s-(2-hydroxypropyl-)-urea and ,N’-bi s-(2-hydroxybutyl-)-urea.

The dihydroxy compounds used for the synthesis of the polyurethanes are compounds with molecular weights of from 600’ to 6,000, preferably 1000 to 3000, for example polyesters, polyethers, polylactone esters, polyacetals, polycarbonates, mixtures of these groups or condensates of these groups, e.g. polyester ethers, polyester lactone esters or polycarbonate esters and others, with melting points preferably below 6o°C and most preferably below 50°C, of the kind which have already frequently been described for the synthesis of such segmented polyurethane (urea) elastomers. Examples include adipic acid esters of hexane-1,6-diol, 2,2-dimethylpropane diol, butane-1,4-diol, 1,2-propylene glycol and ethylene glyeol or polyesters of mixtures of diols to lower the melting point in the polyester. Polypropylene glycol ethers, particularly polytetrainethylene glycol ethers, give rise to products which are very resistant to hydrolysis. Polycaprolactone esters or mixed esters and hexane diol polycarbonates or mixed polycarbonates, as well as adipic copolyesters with long chain diols (e.g. with hexane-1,6-diol) are also particularly preferred on account of their increased resistance to hydrolysis.

The dye absorption may be improved by using about 0.03 to 0.25 mol per kg of diols which contain tertiary amines, such as N-methyl-N,N-bis-(p-hydroxyethyl famine or N-methyl-N,N-bis(p-hydroxypropyl)«amine when preparing the isocyanate prepolymer as described in German Offenlegungsschrift No. 1,495,830.

Any of the known organic diisocyanates may be used but the following are preferred: Diphenylmethane—4,4'-diisocyanate, the tolylene diisoeyanate isomers, diphenylether-4,4-diisoeyanate, hexane diisoeyanate, dieyclohexylmethane-4,4-diisocyanate and 3-isocyanatoraethyl-3,5,5-trimethyl-cyclohexane isocyanate.

The reaction of the diisocyanates with the hydroxyl compounds to produce the isocyanate prepolymer is carridd out with an excess of diisocyanates, preferably using a molar ratio of oh/nco between 1 : 1.35 and 1 : 3.0. The isocyanate prepolymer obtained should preferably contain from about 1.8 to 4.0$ by weight of isocyanate groups in the solid prepolymer subetanoe.

Formation of the isocyanate prepolymer from its components including the diol component 1 according to the invention may be carried out by known methods with or without solvent.

If desired, all of the components may be reacted together in solvents such as chlorobenzene, toluene, dioxane or, preferably, highly polar dimethylformamide or dimethylacetamide at temperatures from 20 °C to 100 °C to form the - 14 I 3 4 3 1. prepolymer or, alternatively, part or all of an isocyanate prepolymer may first be formed frcm the dihydroxy ccmpound having a molecular weight of 600 to 6000 and subsequently reacted with mcncnethylolether diol (I) to produce the final isocyanate prepolymer in which diol Is incorporated in the molecule. The statistical form of distribution of (I) within the isocyanate prepolymer can lx; regulated according to the method employed.

According to the invention, the monomethylolether diols (I) are used in quantities in the reaction for forming the prepolymer such that 0.1 to 10 $ by weight of diola (based on solid prepolymer substance) and preferably from 0.25 to 5.0?» by weight is built into the prepolymer. Since the weight of chain lengthening agent is of only minor importance, it can he assumed that approximately the same quantity is incorporated, based on the segmented poly(urea)urethane elastomer. One factor which reliably characterises the cross-linking density is the mVal per kg of CH^-O-R’ groups since it indicates the equivalents of built-in cross-linking groups. The polyurethane should contain from 5 to 500 mVal and preferably 20 to 200 mVal of cross-linking equivalents (see Examples). An insufficient quantity of crosslinking groups is, of course, unable to release the crosslinking reaction effectively but an excessively large quantity of cross-linking groups is also a disadvantage because it modifies many of the properties (for example elongation at break, modulus, see Examples). It is therefore particularly advantageous fo incorporate 25 to 150 ttVal of CHg-O-R' groups per kg of polyurethane.

The reaction to form the prepolymer is preferably carried out in dimethylformamide or dimethylacetamide as solvent at reaction temperatures of from 20 to 60 °C for 20 to 200 minutes. 2 3 4 31 Hydrazine derivatives (i), x = 1 can readily be used in tiie prepolymer formation reaction but derivatives of (I) \ = 0 must generally be reunit'd under ml Ider eeudt ί ions* (e.g. at 20 to 40°C) because they are more highly reactive.

The resulting isocyanate prepolymer modified by the incorporation of (I) is reacted by the usual methods of chain lengthening with approximately equivalent quantities of bifunctional NH-active compounds in highly polar solvents such as dimethylformamide, dimethylacetamide or dimethylsulphoxide to form highly viscous solutions of poly(urea)-urethanes.

If 5-isocyanatomcthyl-3,5,5-trimethylcyclohexaneisocyanate is used more or less exclusively, socalled bifunetional soft solvents such as toluene/isopropanol mixtures may also be used.

The H-reactive chain lengthening agents used may be glycols or water but are preferably compounds with molecular weights of from 52 to about 400 in which the hydrogen which is reactive with isocyanate groups is attached to nitrogen atoms and which have the formula N„H-Y-NHO in which Y represents a single bond (i.e. hydrazine) a divalent aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic group (i.e. diamines); 0 the group -iin-c-x1-z-x2-c-nh- , in which Z represents a divalent aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic group and X2 represent independently of each other a single bond, -0- or -NH- (i.e. a dihydrazide,a dicarbazinic ester,a disemicarbazide or a semicarbazide 0 hydrazide etc.); the group n (in which 2, and X, have the Z-Xj-C-NH *· meaning defined above), i.e. aminohydrazides or aminosemiearbazides; or the group -NH-CO-NH- (i.e. carbodihydrazide).

The following are examples of chain lengthening agents represented by the formula HgN-Y-NH,,: Hydrazine or hydrazine hydrate (see German Federal Patent No. 1,161,007); primary and/ - 16 4 343i nr aliphatic, cycloaliphatic, aromatic or heterocyclic diamines, preferably ethylene diamine, 1,3-diamino-cyelohexane, propylene-J,2-diamine and/or m-xylylene diamine (see German Federal Patent No. 1,223,154 and U.S. Patent Specification No. 2,929,804 and No. 2,929,803); German Auslegeschrift No. I,c34,714); uihydrazides, e.g. carbodihydrazide, adipic acid, and hydrazide (see German Federal Patents No. 1,123,467 and No. 1,157,386); aminocarboxylic acid hydrazides such as aminoacetic acid hydrazide, β-aminopropionic acid hydrazide (see German Auslegeschrift No.1,301,569)5 semicarbuzide hydrazides such as a-semicarbazido-acotic acid hydrazide or β-semicarbazidopropionic aeid hydrazide (see German Federal Patent No. 1,770,591) or other known NII compounds of the kind which have been described above and elsewhere, for example also in German Offenlegungsschrift No. 2,025,616.

The particularly preferred chain lengthening agents are ethylene diamine, propylene-1,2-diamine, hydrazine, β-aminopropionic acid hydrazide and β-semicarbazidopropionic acid hydrazide. Minor quantities of so-called co-chain-lengthening agents may also be used to modify the properties (e.g. small quantities of 1,3-diaminocyclohexane or water in addition to ethylene diamine as main chain lengthening agent).

Minor quantities of monofunctional amino compounds such as monoamines (diethylamine), monohydrazide derivatives (acetic acid hydrazide, picolinie acid hydrazide or butyl semicarbazide) and asymmetric dimethyl hydrazine may, of course, also be included.

The highly viscous elastomer solutions obtained can be shaped by the usual processes, for example by brush coating on substrates and evaporation of the solvent to form highly elastic films and foils, by doctor application on textiles to form textile coatings or by coagulation of solutions (if indicated with the addition of non-solvents) to form microporous foils for the manufacture of synthetic leather. The most important and preferred use of the elastomer solutions is as spinning solutions for spinning elastomer filaments.

One advantage of the self cross-linkable polyurethane systems of the invention is that even in processes of wet coagulation or wet spinning there is no risk of the crosslinking agent being washed out with the solvent or reduced in its concentration. This is particularly important in synthetic leather coagulation processes where coagulation in dimethylformamide/water mixtures followed by washing would lead to a loss of additive cross-linking agent.

The high stability of the solution containing the self cross-linkable polyurethanes against premature unwanted cross-linking in solution is particularly advantageous.

The solutions can he stored for many weeks ready for processing without undergoing cross-linking. Xn some cases, even the shaped polyurethane products can he obtained in an uncross-linked state, for example elastomer filaments can be spun and processed before they are cross-linked. It is only in the final process specific to the particular product for example the thermal shaping of knitted fabrics produced from polyamide/Elasthane filaments, that the cross-linking reaction is released by the temperature employed so that, for example, degradation or tearing of the filaments in the knitted fabrics is prevented.

The shaped products obtained may therefore still he un-cross-linked (at low temperatures, say helow 100 to 110°C) or partly or completely cross-linked (at high temperatures and/or prolonged heating times), depending on the conditions employed in the shaping process (mainly the shaping temperatures). The cross-linking reaction will generally be controlled according to the process employed and the required use purpose.

The final heating process may be carried out relatively slowly, for example filaments may be heated on bobbins at 120 to 150 °C for 20 to 120 minutes or it may be carried out more rapidly, for example coatings may be dried in drying channels at 130 to 180 °0 for from 1 to 5 minutes or on high temperature treatment apparatus such as heating rollers or heating grooves where the surface temperatures or air temperatures may be as high as, for example, l6o to 250°C and the heating times only 0.5 to 10 seconds. If the heating time is very short, even higher temperatures may be* employed (e.g. in infra-red heating paths).

Catalysts for the cross-linking reaction are not necessary although they may be employed where acceleration of the cross-linking reaction is desired. Any of the known accelerators for methylol(ether) or formaldehyde reactions may be used as catalysts in the usual quantities, for example acids such as acetic acid, tartaric acid, citric acid, trichloroacetic acid, benzoic acid, ammonium chloride, ammonium chloride/ammonia mixtures, magnesium chloride, zinc chloride and other acids, acid salts or compounds which are acid in reaction.

Explanations of the measuring processes and standards used In the Examples The parts given in the Examples are parts by weight unless otherwise indicated.

The molecular weight of the polyurethane elastomer is expressed in terms of the (q^ value, the so called inherent viscosity: (¾. )A = In 13431 wherein hz is the relative viscosity of a soLution of the polymer in hexamethylphosphoramide at 20°C end c is the concentration in g/100 ml of solution. The results were obtained with c = 1.

A high value for nvi or insolubility of the shaped product (corresponding to ?i/i—^oo) indicate a high resistance to thermal degradation which is required for methods of fixing by heat and especially for the thermal deformation process already described above.

Investigation of the filaments or foils for their elastic properties was carried out by the measuring methods given in Belgian Patent Specification No. 734,194 in which the elongation at break is measured on a tearing machine and the length of specimen clamped into the machine is controlled by a light barrier with compensation for the amount of slippage in the clamp.

The elastic properties are expressed in terms of the modulus 300% (in the first elongation curve), the modulus 150% (in the third return curve) and the permanent elongation (after 3 times 300% with elongation velocities of 400% per minutes, 30 seconds after release of the load).

Determination of the hot water elongation Tne elongation of a piece of filament 50 nm in length is measured by a stretching device controlled by a force measuring head until the filament has a contraction tension of 0.25 mN . dtex This tension is maintained, if necessary by continuously increasing the stretching, and the amount of elongation is determined after a loading time of 25 minutes in air (first value). The stretched filament is then dipped into water at 95°C while the load is maintained and the total elongation is read off after a further 25 minutes - 20 4 3 4 3 ( loading time in water (2nd value). In the third stage, the stretched filament is lifted out of the water, the load is removed completely and the permanent residual elongation is determined at the point when the filament is free from tension (3rd value). All values are given in percentages of the length of iilament clamped into the apparatus in accordance with the following scheme: 1st value 2nd value 3rd value ιο Elongation in air at 20°C after 25 minutes loading under 0.25 mN dtex Elongation in water at 93°C after 25 minutes loading at 0.25 mN dtex Residual elongation after complete release of load in air at 20°C Lil Lil Lil The smaller the second value (elongation in hot water in relation to the first value) and the smaller the third value (permanent elongation after release of load), the better are the hydrothermal properties.

Determination of the hot water tension drop (HWTD) of elastomer filaments A 100 mm length of filament clamped into the apparatus (preliminary tension weight 0.9 mg/dtex) is stretched by 100i at 20°c and the resulting filament tension (mN/dtex) is measured after 2 minutes (1st value). The filament is kept stretched by 100i while dipped into water at 95°C and the tension obtained after 3 minutes under these conditions is determined (2nd value). After this measurement, the filament is removed from the water bath and left at room temperature for 2 minutes. The prestretched filament, still clamped into the apparatus, is then relieved of load until free from tension and the permanent residual elongation is immediately determined (3rd value).

The results are expressed as follows In the Examples (abbreviation HWTD) Tension in air at 20°C mN/de tex HWTD Tension in Ho0 at 95°C mN/dtex Residual elongation after release of load The higher the second value obtained (tension in hot water in mN/dtex) and the lower the third value (residual elongation after treatment in relaxed state) the higher are the hydrothermal properties.

Determination of the heat distortion temperature (DDT) of elastomer filaments The titre of elastomer filaments which have been laid out for about 3 hours under normal atmospheric conditions without tension is determined (a piece of filament under a preliminary load of O.OOJ mN/dtex is weighed).

An elastomer filament clamped for a length of 250 mm under a preliminary load of 0.018 mN/dtex is suspended in a glass tube filled with nitrogen at room temperature.

The tube is surrounded by a heating jacket filled with a stream of silicone oil heated to a controlled temperature.

The temperature in the tube is at first raised to about 125°C in about 30 minutes. The temperature is subsequently increased at the rate of 2.1°C per minute until the elastomer filament has elongated to more than 400 mm.

An X-Y recorder is used to plot the temperature changes (along the abscissa) and elongation of the sample (along the ordinate) using a ratio of X and Y coordinates so that, for a relative change in length y of 0.8% per degree rise in temperature, the gradient of the curve is 45°C. ‘ degrees “ length οϊ sample under load at room temperature The heat distortion temperature is the temperature 4 3 4 31 read on the abscissa when a vertical is dropped from the point of contact of the 45° tangent with the temperature/ elongation curve.

The thermal resistance of thn elastomers generally increases with the HDT value.

Determination of the heat tearing time (HTT) of elastomer filaments An elastomer filament is fixed between two clamps (10 cm apart) and stretched by 100%. In the stretched state it is placed on a chromium plated metal plate 4 cm in width which is heated to 193°C hy thermostatic control.

The filament either tears after a certain length of time on the plate or remains stable. If the filament remains j stable the test is stopped after about 3 minutes (Figure given in results: 180 sec.). The figure for the HTT value is given in seconds (sec) at which rupture of the stretched filament is observed at 193eC.

This test was developed by simulating the behaviour of the filaments in a knitted fabric of polyamide and Elasthane filaments, where it was found that the results obtained by the simplified method of measurement described above are basically the same ns those obtained when a loop of polyamide-6 filament is measured against a loop of elasthaiefilament (simulation of the knitted stitches).

The HTT results obtained show a relatively good correlation with the behaviour of Elasthane filaments under 1 conditions of distortion by heat (stretching of surface area by about 50 to 100%; distortion temperatures about 180 to 200°C. - 23 i 4343 t Examples X. Methods of preparation Preparation of monomethylolether-urea- (or - semicarbazido-)-diols (I, x=0, l), a) Monomethylolether-semioarbazide-diols (I, x = l) General Method Mol of Ν,Ν-bis-(hydroxyalkyl)-hydrazine (for example N,N-bis-(p-hydroxyethyl)-hydrazine) was dissolved in about 150 ml of chloroform. A solution of about 1 mol of alkoxy methyl isocyanate (for example methoxymethyl isocyanate) in about 5θ ml of chloroform KBS then slowly added dropwise while the reaction mixture was vigorously cooled to a temperature between -30°C and -2°C.

If the substance precipitated while the reaction mixture was left to stand at room temperature, it was suction filtered and if necessary recrystallised.

If the substance did not crystallise, the solvent was removed by suction filtration under vacuum and the oily substance was used as such (see Table 1, Compounds C and D).

.NH.CONCH„.OCH, H0.CH2.CH,% ώ “ 9 HO.CHg.CHg' H * J (Compound C, Mp 89 to 93°C) Compound C and D (I, x = l) have not previously been described in the literature. b) Monomethvlolether-urea-diols (ΐ, x = 0) General Method Mol of aminodiol (for example diethanolamine) was dissolved in about 175 Ml of anhydrous chloroform. A solution of 1.05 mol of alkoxymethylisocyanate (e.g. methoxymethyl isocyanate) and 80 ml of chloroform was then slowly added dropwise with vigorous cooling to between -30°C and -2°C.

When the reaction mixture had been stirred for a further 2 hours, it was warmed up to room temperature and the solvent - 24 ho.ch2.ch2v ho.ch2.ch2 N.NHc+0CN.CH„.0CBL43431 was evaporated off under vacuum. The products obtained had an oily to lardy consistency and were suitable in this form for incorporation in the polyurethanes in accordance vzith the invention (see Table 1, compounds A and B). ΗΟ.ΟΗζ,.ΟΗ». HO.CH~.CH-\ ά ^NH + OCH.CH~.OCH,.—f d ά N.CO.NH.CH?.CCH, H0.CH2.CH2x * 3 HO.CHg.CHZ 5 (Compound A (oil)) c) Diol comparison compounds The comparison compounds described under E and 3? in Table 1 were obtained by basically the same reaction from N,R-bis-oxethylhydrazine and butyl isocyanate or phenyl isocyanate. d) Polymeric cross-linking agent (G) based on diol-I/C and diphenylmethane-4,4'-diisoeyanate —EI7H.CO.0.CII2.CH2.N.CIi2.CH2.0.CO .NH-/7 ^-CHg-/7-^NH \=/ \=r=/ io.NH.CH2.O.CH5 (Compound G) 207 Parts of the diol I/C (see Table i)were dissolved in 200 parts of dimethylformamide. A solution of 250 parts of diphenylmethane-4,4'-diisoeyanate in 257 parts of dimethyl formamide was then stirred in dropwise at 0 to 5°C. No isocyanate could be detected when the 50% solution had been stirred for a further 3 hours at about 30°C. e) Bifunctional bis-methylolether cross-linking agent (E) obtained from octadecane-1,12-diol and methoxymethyl isocyanate CHj.0.CH2.rai.C0.0.C,(CH2)10.CH2.0.C0,KH.CH2.0.CH3 θ6Η13 (Compound H) 285 Parts of octadecane-1,12-diol were dissolved in 2700 parts of chloroform. A solution of 174 parts of methoxymethylisocyanate in 1C0 parts of chloroform was then added dropwise with stirring and cooling at 0°C. 4343:1 After 15 hours at room temperature, the isocyanate groups had completely reacted. The residue obtained after removal of the solvent was a colourless, crystallising mass which was readily soluble in dimethylformamide. - 26 4 3 4 3 1 Table 1 Preparation and properties of the monomethylolether diols I and comparison compounds φ +3 +> ti W ω to fl o J •rl fl -P QJ 0) P, fl O CO fl flo G) (Dio tf +5 cd tO rd rd O ss w o o tt A ox CO Ή rd Η -P O O <0 ‘H « fl tf I O -P Ο β 0) O fl o o tt tf fl Ο d· fl tf ω fl f co a tf O φ o P fl fl tf Η Φ O fl •Η O tf tf to rd fl fl fl O fe» O O K> σ* x σ' oo s > l>> s fd P *0 rd fl tf fl •rl TO • (0 O rd a rd σι I X o tO I J? o tO ο 1 o oa t— | OJ | \ 1 X \ J x o fl* O o fO σι 4 tO 1 o o a oP A o CM I o' ? I ο ο o tO o to & Ο ι ο ι ο ΙΛ ο Lf\ OJ OJ Γ- ΟΙ 1 1 LO O • Lf\ O Ο * 1 1 8 ! Ο • Ο • V* Τ- Τ- *— I γ— τ- ·» o ♦ Ο Ο 8 ϊ ο • ο • »- <- 1 τ— τ— o o W o o tO CJ CM cm a a CM cr> K\ W a S a o=o ο o a ΙΛ (Λ 5 a a o o CM o 8m a o a κ = 0 Z \cmo=o a a o a r~\ tf o a a o o CM o tf tf δ Ο tf tf ο ο Ο to ΙΟ ο ο tr ο ο tf tf ο ο tf tf tf ο ο tf tf ο S-\ Ζ—\ <·> tf ο ο o %.

S’ z\ O □ •r| Ol g S 1Λ ω Φ o s. a /a 8m ooo a a cm a a a ooo ο o o a a a ‘or the sake of simplicity, in the Examples which follow, each diol-I will only be represented by the letters A to S') given in the table. - 27 43431 II. General method :for the preparation of the polyurethane elastomer solutions of Examples 1 to 11: 1690 Parts (parts always means parts by weight now and in the text which follows) of a copolyester of adipic acid, hexane-1,6-diol and 2,2-dimethylpropane-l,3diol (molar ratio of the diols 65/35) having an 0Ξ number of 66.4 were mixed in the quantities given in Table 2, column 3 or Table 4, column 3 at temperatures of from 30 to 40°C. This mixture of polyester monomethylol-ether-diols was reacted with the quantity of diphenylmethane-4,4'-diisocyanate given in column 4 and the quantity of dimethyl formamide required so that the isocyanate prepolymer had a solids content of 70 parts, employing the reaction conditions shown in column 5/6, to produce an isocyanate prepolymer solution (for isocyanate content based on the solids content see column 7 of Tables 2 and 4).

The Isocyanate prepolymer solution was then stirred with vigorous mixing into a solution of the chain lengthening agent (ethylene diamine [reaction as carbamate according to German Federal Patent No. 1^223^154) or β-semicarbazidopropionic acid hydrazide) in dimethylformamide, using the given slight excess of chain lengthening agent. If necessary, the excess of chain lengthening agent was then reacted with small quantities of hexane diisocyanate (see German Federal Patent No. 1/157/ 386) until a viscosity of at least 400 poises waB obtained.

III. General method for the manufacture of shaped PO elastomer products The elastomer solutions were spun by a standard process in which the solutions wereextruded through nozzles having 16 apertures 0.2 mm in diameter into a vertical heated spinning shaft (wall temperature about 23O°O, additional injection of hot air at 240 to 300°C) and drawn - 28 43431 off at a rate of 100 m/min. After their passage through a talcum coating bath, the filaments were wound on spools either without stretching or with 30$ stretching.

The filaments containing cross-linking diol ineor5 porated in the molecule were in most cases at least partly cross-linked hy the time they left the spinning shaft and insoluble or only partly soluble in dimethylformamide.

For testing purposes, the elastomer filaments were heated at 130°C for one hour and then measured (see results of measurements in Tables 3 and 5).

IV.' Examples 1-5 Polyurethane elastomer solutions or shaped products were produced by the methods described in II and III above(see Table 2).

As can be seen from the results given in Examples I to 4, and 5, preparation of the elastomer solutions with incorporation of the cross-linker diols-I could be carried out substantially in the same way as preparation of elastomer solutions without the incorporation of diols (see Table 2).

The elastomer solutions obtained had practically the same flow properties and spinning properties and were stable in storage at room temperature.

When increasing quantities of cross-linker diol-I were incorporated in the prepolymer, the properties of the cross-linked elastomer filaments (see Table 3) generally changed in the following manner. The elastic properties were modified at least in the sense of a reduction in the elongation at break and increase in the moduli both at 300$ elongation and on return after elongation (e.g. at 150$) and a reduction in permanent elongation.

Of greater importance, however, were the improvements in hydrothermal and thermal properties, for example, 3431 in .the hot'water elongation test the extent of elongation in water (second value) and the permanent residual elongation after removal of the load in the water treatment; also the amount of tension of the filaments in water at 95°C under 100% elongation (second value HWTD) and the permanent residual elongation after removal of the load as well as the value for the heat distortion temperature (HDT) . One feature which was of major importance in deciding the usefulness of the filaments for practical purposes was the improvement in the heat tearing time (HTT) of filaments stretched by 100% at 193°C (corresponding to the conditions of so-called thermal distortion of knitted fabrics). In this respect, the nature of cross-linking according to the invention produced an outstanding improvement in the behaviour of the filaments under conditions of stretching at high temperatures. The particular crosslinking prevented flow of the filaments at the high temperatures employed for thermal distortion and rupture of the filaments. Knitted fabrics produced from filaments which had been cross-linked according to the invention did not show the usual rupture of the filaments in the fabrics.

The quantity of cross-linking agent used according to the invention was low and, due to the more advantageous distribution of the cross-linking points throughout the soft segment, effective cross-linking (insolubility)was achieved using quantities of cross-linking agent which were not sufficiently effective when the cross-linking agent was used as an added methylolether compound (e.g., G, H-Comparison experiments 4 and 5) and not incorporated in the prepolymer. Indeed, the addition of such compounds in accordance with the comparison experiments had a deleterious effect on these properties. - 30 4343 The comparison experiments 2 and 3 demonstrate that the improvements in the properties are not based on the incorporation into the polyurethane of diols which have a very similar structure (Ii, P) since these comparison experiments also show a marked deterioration in properties The process according to the invention also improves the resistance of the elastomer filaments to hydrolysis.' The values for residual strength after vigorous hydrolysis are distinctly better than in the uncross-linked filament. 4343X φ -ρ α fl-H φ a tOrt Φ«Η Ό to fl Φ •rt fl fl Φ ΦΗ XJ ί>ϊ •8.5 fl φ φ Η fl •rt (0 Xi Ο Μ,. Ρ Φ^ •rt we W-rtCM Ο Ο II ' ϋ fto ω •rt fl Ρ >«rt <0 ΟΟΟΟιΛ LA o o CMNlACOlN c— IS ca CACAO'COiN e <0 K0 W fl ο •Η I ο ω ¢4 φ fl ο Ρ (Ω rt rH Φ XI Ρ Φ h rrt Ο ft Φ Λ Ρ Crt Ο fl Ο •rt α! a 8rt ft α> XI 4J rt Ο •rt •rt Ά fl Ο ϋ fl Ο •rt Ρ Ο <0 Φ « CM Ρ oS •rt\ Ρ Ο rt ο 01½ CO LOIOIO O-O-OOOOOO OO Ot ft Φ •©ts.

Hrt OH tO rt § °s τ)4» © o «9« © 2 a rt !»rt *rt A S •rt P P*rt · Cltf ft ©(300 © Ο ©o « os4 M 41 41 !S SiU Sft JO ΙΛ o P to fl rt o υ § “ H I w rrt O ·· •rt fl O flp ss •rt § H.rt W Φ ωχ} o P fl υ OJOJOJOJOJ ΟΟΟΟΙΛ tOtOtOLOVO «-’-OlOltO o fl hO IA IN fl O Φ ♦ •rt *“ H I — (0 w o fl o ss • l> CM O s a a ι CN CO CM S' IO ΟΟ o oo Ol io ©· ooeu\co fA s Ol K0 LA H H ί ί Ο O fAfAfA Γ» rt LA IA LALACM CM CM H K\ fl K\ K\ -% ^a-a vi ©ft & ·© 60 ·-— © o 14. to © 6DbOW xi rtrto 41 H\O ΟΛΗ OJ OH>S HHSCM fl o •rt P rt fl o & o § H ---O CACOCNOLA ·Η • · · · · OO tOifi lOd IOC-OCOO . ©•-ίιοιοιο ω .......... Λ4 --a •rt r-l I w w o fl o K\cr»oeu> • · · · · •“Νο-σικλ «— Ol -t ΟΊΟ rnoooo OllOOOO ’-OJ’fl ! P w O fl o •rt P C0 fl O & o o fl H CO ΟΟ tO ΙΟ ft £. to H m rt I rt 41 © H M « © rt rt ηhh H rt rt (3 ft ο © ο σ o a a Ho 0,41 © xi ra 41 W © © rt © OOH OH' fl-H Ο ©H' ο H ra ©' £ OOOOfl ft rt © x>.

© H ft o IK’ OltOfl-lO to ώ o •P α ο ο 0) α «μ φ & φ JCJ ft ti ο •rl +1 ti pH η § o H fl β) rt a fc S3 0 (0 Uh 6 o 9*> in (N o rt υ •3 « H -rl H P (0 CQ Li ω ΰ ? fi Ρ φ O O O 0 •rl o ® rt Ss o ft? ss fl§ o ?? « 23 P I IH O a o •d •P o w O/Τ' o -P I Xi fl) hDti •Η Φ Φ jJ * -P Φ JO ti to H •P o sft P< 4« KO tn ti H ft I ti o •d P ti H O ω o •P •s •d Φ £ £ in P « Pi co om I CM >, fi (OP Η OH PiHra _ 01¾ ri 3OCD O HOlCM H OH 0 •ΰ ra> o I cii a r- -rl 4J r- (D Lfl I 2-rt Hl fi 4) a m 5 3-p o w S .s <0 « M P _.P o3^ a O ft O “CM A IU*” |*§ OS m Pl p 0 fi v o fl I Ο ω Φ Ή 2 g p fl (0 M On JO PHM P PP I rt fl 3 rt P ®H fl O OO rt ι g ra jo Η 0 43 o cm ra P+iS i ti B® e „h jo ra τ ω p Η I, £ rt P fi η o p Si ri ft' •fiH»H £££-° η 5«- in •aj ai<-· o B (0 W ra a Ο ®ΉΟ\ Ο Ρ Ό ΙΛΗ CM p fl lfl o o o > CD CM ITl r- L\ r~ φ o £S O • • t— ·· ·· r~ CS if- CJ CM • re CM Cl o ΙΛ K\ CJ t— Cl o KD IS ti* l o I o ΙΛ fC o o « « , ts LC CM co ti* rc LT\ K> CJ Cl I U U 11 H WirvrEl COO O PrP B - 33 131 Table 3 Properties of dry spun elastomer filaments - Chain lengthening agent ethylene diamine imple mVal/kg Tensile Blonga[o. of CHpOCK, strength tion at built into cli/dtex break the mole- /e cule Modulus Modulus Permanent at 300% at 150% elon;ation mN/dtex 3rd re- after turn 3 x 300% from in % 300% mN/dtex orporation of the cross-linker diols according to the invention (c) 0.56' 536 1.28 0.20 20 50 (C) 0.65 490 1.77 0.21 16 100 (c) 0.65 496 1.83 0.21 19 200 (C) 0.60 365 2.80 0.21 18 I 100 (D) 0.64 490 1.54 0.20 20 ipar ison example without cross- -linking agent •1 - 0.68 571 1.29 0.20 19 iparjson examples: Incorporation of structurally similar diols without cross-linker group •2 (molar quantity corresponding to Example 3) 0.65 515 0.66 512 1.54 0.20 22 1.64 0.20 19 parison examples: Addition of polymeric cross-linking agents (G) molar 0.57 508 1.45 0.19 22 quantity of CIIgOCHj Addition of bifunctional cross-linking agent (H) corresponding to 50 mVal/kg 0.60 513 1.32 0.19 26 mple 50 (C) 6 0.72 482 1.32 0.20 10 parison example • δ - 0.65 540 1.12 0.20 15 Hot Water Elongation Elongation Elonga- Residual ia air at tion in alonga20°C HpO at tion % 95°C after re% moral of load % mN/dtex HWTD (Hot water tension drop) Tension in Tension Residual air at SCO in iUO elongaat 95°C mN/dtex rfSral of load % 48 107 24 0.384 0.233 31 47 98 20 0.401 0.253 30 51 103 40 0.435 0.230 38 50 86 25 0.440 0.286 25 53 112 29 0.370 0.227 31 50 179 74 0.431 0.194 44 40 204 85 0.404 0.150 49 47 175 63 0.411 0.214 44 54 189 87 0.404 0.164 45 84 166 39 0.302 0.196 28 70 166 53 0.320 0.192 34 131 •ydrolysis in % of original strength after i hrs. 16 hrs. 32 hrs.

HDT Heat tearing Solubility in DMF time at oG 193°C/1CO% elongation in sec.

(HIT) 132 105 88 179 62.2 insoluble 104 96 69 180 101.3 insoluble 111 103 83 180 >180 insoluble 93 92 92 185 »180 insoluble 109 95 66 178 171.1 insoluble 96 79 69 180 32.6 soluble 174 16.2 soluble 176 17.9 soluble 177.5 26.5 < more than < 80% < soluble 174.0 21.7 ) 167 73·9 insoluble 167 6.7 soluble - 36 43431 Example 6 In this Example the preparation of a softer polyurethane (urea) elastomer which contains about 2.27% of NCO in the prepolymer is deseribed. By softer is meant a polyurethane with a smaller prcporticn of isocyajiate group. Uhe method of preparation was basically the sane as in Examples 1 to 5-see Tables 2) and 3).

Here again the poor value of the heat tearing time HTT was so much improved by the cross-linking reaction that thermal shaping of the filanents could safely be carried out although the hardness due to the isocyanate ccntent (isocyanate hardness)was considerably reduced. As a general rule it may he said that, within a test series in which the isocyanate content in the isocyanate prepolymer was progressively increased, the HTT (heat tearing time) increased with increasing hardness of the Isocyanate prepolymer or, in other words, with increasing number of hard segments in the filament. Since, however, the tendency of the solutions to become pasty increased with increasing isocyanate hardness so that filtration became progressively more difficult, it was desirable to adjust the solutions to a lower isocyanate value. Even then, the cross-linking according to the invention still provided sufficiently high HTT values.

The elastomer spinning solution of Example 6 was still uncross-linked and easily processed after it had been left to stand for 12 weeks.

The elastomer solution could also be spun into filaments by the usual wet spinning process and, after the final heat treatment at 130°C for one hour, the filaments obtained were found to be cross-linked in the same way as filaments produced by the dry spinning process. Coagulation obviously caused no loss of cross-linking agent since the cross-linking groups were incorporated in the polymer chain. 131 Examples 7 to 11, CE-7 The Example describes the preparation of polyurethane elastomers by chain lengthening with HgH.NH.CO.NH.(CH2)2.C0. NH.NHO. The reaction of the prepolymer with chain lengthening agent was basically carried out in the same way as described in Examples 1 to 6 (see also Table 4) but the semicarbazide derivative, which was dissolved in twice its weight of water,was mixed with dimethylformamide before it was reacted with the isocyanate prepolymer. Without crosslinking agent, elastomers of this composition were less stable under conditions of heat distortion (heat tearing time HTT approximately 1 second). The cross-linking reaction according to the invention, on the other hand, considerably improved the response to hydrothermal conditions (hot water elongation, hot water tension drop and heat tearing time) (and HDT) and the filaments were also much more resistant to hydrolysis.

If the molecular weight was measured before and after heat distortion (30 seconds at 180°C), theftyi value (10 g/l in hexamethylphosphoramide at 25°C)was found to drop in the comparison experiment from 1.0 to about 0.70 while the cross-linked filaments continuedto be insoluble in the solvent as their very high molecular weight was preserved, C> Ό •/Η bl Λ fi •υ Η rt ο •Η ϋ Ο •Η Ο rt Ο rt •Η Ν (ί Ρ rt (0 ο *Η Ei φ ιη I σι Ρ Π Φ U <β tc £ «ri c: φ XI +ρ ϋ Φ Φ Η rt •Η rt Λ ϋ Μ1 > p Φ ζ •Η 10 10 (0·Η CM Ο Ο II Ο ft Ο ω •η rt -ρ ►> ·Η Φ CM ι-Η S. Ο o rt rt •Η 0) *d φ ο ρ g ο rt φ ω w ρ ο rt φ χ> Λ op rt rt Η fri \y Ο W 5 Ο Φ · η rt rt p ‘Η »Η •Η ΓΗ β rt rt ο ο rt Ο L •Η rt Ρ Φ Φ ϋ ft rt Ο φ α 3ο φ Φ Ρ ps φ ιη ρ Η Ρ & ftrO ΙΑ Ο Ο <- CM LA CM ο CM rt rt ES rt kO ΙΑ rt rt rt IA LA IA LA IS IS ES O IS O O O c— • O • CM CO Ch 00 • IS Ch • & • CM CO ES CO • CM CM CM CM CM CM O 0 LA iA O O LA in CD LA CS LA CM CU fA CM LA rt rt fA LA LA CO fA LA CM | r~- i fA Φ Φ Φ IS LA r~ O O υ t— CM fA es ο ΙΑ _ 00 ΙΑ ΙΓ\ lA LTS ΙΛ CS IS IS ΙΑ Η Ο Ρ4 TJ ο Ρ c φ Η Ρ tn xi Η Ρ b0 Ο<λ μ ·Η •HP Φ Φ rt « ft ζ I Φ rt b0 Φ Φ ζ-\ Ρ fA Ρ t3fcow φ α . ν« ο Η·Η\Ο Ο,Μη (Μ /Η Λ Φ irt ί>ϊ·Η S Ο ΧΙΗ Ρ 1 φ ω rt w φ Ο ΟΗ ΦΗ rt rt Ο Φ XJrs Ο Ο ·Η « Φ γrt Φ Ί fc5 φ γΗ θ’,? Μ*5 Μ O rt <0 io co < • · • ES ch fa rt LA rt la rt 0 ο ο CM Η Ο •Η rt rt •Η Η ί (0 ω ο rt ϋ ρ rt ο Ρ Ρ •Η ο ο rt* Φ Η ft rt φ Η φ rt ο «I •Η Cco σ> Ο <<— t— - 39 οο ϋ IS I W ϋ 1431 Table 5 Properties of dry spun elastomer filaments; chain lengthening agent β-aemicarbazido-propionic acid hydrazide Example mVal/kg Ho. CHgOGHj incorporated in the molecule Tensile Elongstrength ation cH/dtex at break % Modulus Modulus Permanent at 300% at 1505c elongation mN/dtex 3rd re- after 3 x 300% turn oc from ' 300% mN/dtex 7 100 (C) 0.69 530 1.86 0.21 17 8 200 (0) 0.62 431 2.70 0.19 ' 18 9 100 (D) 0.60 490 2.07 0.21 18 10 100 (A) 0.51 484 1.87 0.18 22 11 200 (B) 0.60 411 3.03 0.18 22 Comparison example OE-7 - 0.40 452 1.67 0.16 ί8 Table 5 continued Hydrolysis resistance in original strength after 4 hrs. 16 hrs. % of 32 hrs. HDT °C Heat tearing time at 193°C/100% elongation Solubility in sec. .in DMF 103 88 54 179 13.5 insoluble 114 95 79 183.5 90.0 II - 176 27.8 11 - 178.5 15.9 II - 175 37.0 » 64 49 33 175.5 1.0 soluble TABLE 5 continued Hot water elongation Hot water tension drop Residual Residual Elongation Elongation elongation Tension Tension elongation in air in H,0 after in air in H20 after at 20°C at 95°C removal at 20°C at 95°C removal % % of load % iriN/dtex mN/dtex of load % 51 212 84 0.408 0.159 47 35 106 26 0.488 0.209 42 38 192 83 0.440 0.185 57 42 169 70 0.488 0.199 46 34 176 60 0.499 0.196 51 69 >400 no longer measurable 0.301 0.117 57 3431 Example 12 The quantities oi diphenylmethane-4,4*-diisocyanate (MDI) in 80/ dimethylformamide solution given in Table 6 were reacted in each case in 1045 parts by weight of a dihydroxy-polytetramethylene ether (OH number 108) and 22.74 parts by weight of N-methyl-bis-(p-hydroxypropyl)amine with and without and addition of cross-linker diol X/D under the given reaction conditions to produce the isocyanate prepolymer. The prepolymer was then chainlengthened with propylene-1,2-diamine (with the addition of COg) at a molar ratio of NCO/NHg = 1:1.10 in 20/ dimethylformamide solution (see Table 6).

The clear, viscous solutions were applied to a polyamide6 sheet to form a layer about 0.6 mm in thickness which was dried in a drying cupboard at 70/l00°C and then in a heating duct at 140°C for 3 minutes.

The coating obtained according to Example 12 was then insoluble in dimethylformamide, was more firmly bonded to its support and had higher softening temperatures (Δ = io°c)t compared with the products obtained in comparison experiment CE-12, it underwent less discoloration when exposed to light in a Fadeometer for 8, 15 and 22 hours. The sheet obtained by the comparison experiment remained soluble in dimethylformamide. - 42 _ Ο -ί? bO Ή fc rH rt -Η X» £1 0 fc Ο Η ϋ Ο CQ rt s o co ! rt o co -ρ β ω bi α •Η α XI ti £3 Η σ •Η •8 XI Χ> h rH Ο Ρ α ο •0 η & co Ο •Η Ρ a rt Ο W fc a ο Ρ ω « rt Η •Ρ •Η ω σ ο w •Η t> fc Ο •rt +5 fc Η Ο fc ω-κ φ CM co 11 10 rt ϋ Ο ft I fc S3 Ο Ο fc Ort »fc ft Ο O'd'-SbM ο 10 Ή ρ I >.? 0 rt fc Q ,ΟΟΦΟ ο ο •rt «Η 45 , •rt fc *0 0 gn gg1 Ή fi P Pi co o O *“ CM CM* fc •rt „ fl 0 O ° fl Ο·Η pi MP - n HP O co CM O l> o t ΙΛ CM ΐ ίΛ CM ΙΛ Φ r- Ι> .-4- Κλ XI Ρ a Q H S H-°S O 14 til •Η Ρ τί AH © fc, rt «rt Ο fc Ο •Η fc ίΜ Φ fc •rl rt bD l Λ M\ CO rt O 0 fcb> O fc Φ rt ft · fc o S~ $ Φ ΝΊ CM fc Ο CO •rt 0 fcrt 0 ft 8$ 3431 Examples 15 - 14 1925 parts of a copolyester of adipic acid and ethylene glycol/butane-l,4-diol (l:l) (OH number 58.l) were mixed with the quantities of colour diol (N-methylbis-(p-hydroxypropyl)-amine) indicated in Table 7 and with cross-linker diols-I, diphenylmethane-4,4'-diisocyanate and dimethylformamide (in the quantities required to form an 80$ solution) and the mixture was heated under the given reaction conditions to form the isocyanate prepolymer. By the term colour diol is meant a diol which contains tertiaryamine groups which are incorporated into the elastomer to increase its dyeability. The isocyanate content of the prepolymer was determined immediately before the chain lengthening reaction. Chain lengthening was carried out using ethylene diamine of prcpylene-l,2-diamine in dimethylformamide in the form of the diamine carbamates (addition of carbon dioxide in twice < the quantity by weight of the diamine to the amine solution).

The quantity of dimethylformamide was adjusted to produce 20$ elastomer solutions. When the isocyanate prepolymer was introduced into the carbamate solution with stirring, formation of a homogeneous elastomer solution is accompanied hy liberation of carbon dioxide from the carbamate.

The solutions were converted into filaments hy the dry spinning process as described above. The elastomer filaments, Which contain cross-linker diol, were already partly or completely insoluble in dimethylformamide when they left the spinning shaft. Before the tests were carried out, the spools of elastomer filaments were finally heat treated in a drying cupboard at 130°C for one hour or placed on heating rollers at 180 °C to .200 °C for 0.5 to 12 seconds. The solutions containing cross-linking agent had then become completely insoluble in dimethylformamide at room temperature. - 44 43431 Compared with the filaments obtained in comparison experiments, the cross-linked filaments were improved in their hydrothermal properties and resistance to hydrolysis and considerably improved in their heat tearing times (see Table 8). Ethylene diamine normally produced better results than propylene-1,2-diamine if the thermal and hydrothermal properties were compared, starting from the same prepolymer, hut the results were considerably improved hy the cross-linking reaction. :3431 φ α ο Η {>5 Λ Ρ Φ Ρ Ρ •Η £ fcD α •Η β Φ XI υ S *Η η •Η Φ Ρ Ο β Ή & ω cqoj ο φ ο ω η ω ·κ •Η Ο Ο > ft 01 LA ι la ο r— CA <0 ΙΑ ιΑ 5· ι ϊ σι φ β Η •Η τί Φ β Φ Η & •Ρ φ Ν ο Η •8 Ε4 η β φ Ρ « φ £ ο ft β ο τί φ ω φ Ρ W β ο •Η ο W k φ δ ο ρ η φ οι ΙΑ ΟΙ Ο ΙΟ ΟΙ Ο ΙΑ Ο ΙΑ ΟΙ ΙΑ σι ο ΙΑ Ο OJ Ο ΙΑ ω it 1 ca 4· fA | 1 LA I 1 IA to 1 IA 00 Ol tA 1 Ol tA θ Mb S ftp CO fit 1 co IA ca CM i CA CM LA LA 1 LA LA Φ Orl+> fe CO CA 1 fA Η 0 fl • e • Z-S 0·Η (Β f>5 CA IS- 1 o (ri φ Ο·Φ ΡιΡ rA ΓΑ 4· φ α I &S • 1 '-'Φ m ρ CA co φ.Η Ρ S Ο 1 K\ ό ·ΰ Η β e • Φ 1 ο3 h Φ 1 Φ Λ οι •rtfMP LA r IA CO fA Table 8 Iropertica of dry spun elastomer filaments Example m7al/kg No. of incorporated cii2och5 Tensile Elongation Modulus Modulus feraanent strength at break at 500% at 150% elo. gation cN/dtex % mN/dtex 5rd re- after 3^500% turn % from 300% mN/dtex 1CO 0.58 562 1.24 0.19 16 Comparison example CE-13 0.54 614 1.09 0.19 17 14 100 0.57 526 0.75 0.18 12 Comparison example CE-14 0.55 632 0.85 0.20 16 - 47 43431 Table 8 continued Hot Water Elongation Elongation in air at 20°0 Elongation in Hg0 at 95°C Residual elongation after removal load of Hot Water Tension Drop Tension Tension Residual In air in H?0 elongaat 20°C o+. ηςοπ tion after Wdtex Removal of 62 186 58 0.325 0.167 44 64 282 102 0.500 0.151 46 129 325 97 0.201 0.147 35 94, sample failed -^400% - TJ ο β β •Η Ρ β Ο ϋ h Η β τΐ Ρ •rl •Η Ο ’Λ Ο ο •3 w Ρ V< c Μ0·Η co •πΐ *— β ΑΧ Ο β Ο·Η οο ρ Ρ ΙΛ (0 0' Ηί) ρ *“ β Μ Ο ΟΡΗ ω ο ο Αϋ 0° Ρ Λ 44 CM o ΙΑ . -ci L<*P tn • « β W •Η Ο A A P Ρ CQ CQ Φ •Η to Η Η « · Ο·Η Ρ 0) ρ ωω g « -rlU Λ SfH'H κ ong· o O I—1 H p O P β H β H P rH O ft O (0 rH CQ β O β •rl to •rl Ο rH £ Ο <- co 3 8 τ— Τ~ A Α.

A IA LA • • IA lA r- co O- O o.

OJ ι OJ oj σ> o oo 43i Example 15 1200 parts of a hexane-1,6-diol polycarbonate (molecular weight 1925), 25.7 parts of N-methyl-bis-N,N(β-hydroxypropyl)-amine and 408 parts of toluene were heated with 428.0 parts of 3-isocyanatomethyl73,5,5- trimethylcyclohexane isocyanate and 20.7 parts of diol I/C (see table 9). or 405.8 parts of 3-isocyanatomethyl-3,5,5-trimethylcyclohexaneisocyanate without diol i/C (see comparison Example CE-15) at 60°C for about 10 hours, i.e. until the isocyanate content of the isocyanate prepolymer had become constant.

The given quantities of 1,4-diaminocyclohexane (36$ cis- and 64$ trans-) were dissolved in portions of a 1:1 mixture of toluene and isopropanol and reacted with the given quantities of isocyanate prepolymers with stirring. Solutions having viscosities of about 1000 poises at about 25$ were obtained.

If 0.1$ by weight of tartaric acid was added as catalyst to the polyurethane solution which was then used as a finish on synthetic leather sheets or polyurethane coated fabrics in the usual manner and the finished goods were passed through a drying channel at 130 to 150°C for about 2 minutes, the finish obtained according to Example 15 was insoluble in the solvent mixture used for its preparation and had also become resistant to high percentage alcohol while the comparison finish obtained according to CE-15 waa completely soluble or at least underwent considerable swelling and was only moderately resistant. Similar sheets according to Example 15 or finishes had excellent light fastness and good resistance to abrasion and folding. - 50 43431 % UGO Parts of Parts of Parts of Viscosity Stability of in 1,4-diamino toluene/iso- ΙϊΟΟ prep- in poises solution prepolymer cyclohexane propanol aration c = 25% of elastomer mixture solution •s +3 W in m o K\ in ft in m in O om in Oi • O'* CO OJ in fl o ω •H a> Au\ $ o$o

Claims (15)

1. CLAIMS:1. A process for the manufacture of a shaped polyurethane product which is cross-linked with methylol ether groups or is self-cross-linkable with methylol ether groups, in which process a substantially linear isocyanate prepolymer obtained from a dihydraxy compound with excess organic diisocyanate, which prepolymer has been modified by the incorporation of a monomethylol ether diol of the formula HO—R—N—R—OH (W) x O=CNH CH 2 —OR' in which R represents a straight or branched chain alkylene group; R represents an alkyl group and X represents 0 or 1, is reacted in a solvent with a chain lengthening agent, and the shaped product is formed from the resulting solution, and crosslinked during or after the Shaping process where a cross-linked product is to be manufactured.

2. A process as claimed in claim 1 in which the substantially linear isocyanate prepolymer has been obtained from a dihydroxy compound having a molecular weight of from 600 to 6000.

3. A process as claimed in claim 1 or claim 2 in which the chain lengthening agent is water or a diol.

4. A process as claimed in claim 1 or claim 2 in which the chain lengthening agent contains NH-aotive end groups.

5. A process as claimed ih any of claims 1 to 4 in which the chain lengthening agent has a molecular weight of from 32 to 400.

6. A process as claimed in claim 4 or claim 5 in which the chain lengthening agent is a diamine, amino alcohol, dihydrazide compound or hydrazine.

7. A process as claimed in any of claims 1 to 6 in which, in formula (I) R represents an alkylene group having 1 to 12 carhon atoms. - 52 4*343/. ''δ.

8. A process as claimed in claim 7 in which R represents an ethylene or propylene group.

9. A process as claimed in any of claims 1 to 8 in which, in formula (I), R' represents an alkyl group having up to four carhon atoms. 10. Product as claimed in claim 20 or 21. 25. A shaped polyurethane product as claimed in any of claims 22 to 24 which is in the form of a filament, foil or coating. 26. A shaped polyurethane product as claimed in any of claims 20 to 25 substantially as herein described with reference

10. A process as claimed in claim 9 in which R' represents a methyl group.

11. A process as claimed in any of claims 1 to 10, in which, in formula (I) X represents 1.

12. A process as claimed in any of claims 1 to 11 in which the monomethylol ether diol is incorporated in the isocyanate prepolymer in quantity of from 0.1 to 10% by weight, based on the solids content of the isocyanate prepolymer.

13. A process as claimed in claim 12 in which the ether diol is incorporated in the isocyanate prepolymer in a quantity of from 0.25 to 5% by weight, based on the solids content of the isocyanate prepolymer.

14. A process as claimed in any of claims 1 to 13 in which the monomethylol ether diol of formula (I) has been obtained from an asymmetric Ν,Ν-dihydroxyalkyl hydrazine or N,N-dihydroxyalkyl amine by reaction with an alkoxymethyl isocyanate. 15. A process as claimed in claim 14 in which the monomethylol ether diol of formula (I) has been obtained from bis-(fi-hydroxyethyl)or bis- (β-hydroxypropyl)-amine or -hydrazine and methoxymethyl isocyanate. 16. A process as claimed in any of claims 2 to 15 in which the substantially linear isocyanate prepolymer has been obtained from a dihydroxy compound having a molecular weight of from 1000 to 3000. 17. A process as claimed in any of claims 1 to 16 in which the substantially linear isocyanate prepolymer has been produced from a dihydroxy compound and a diisocyanate, using a molar ratio of OH/NCO of from 1:1.35 to 1:3.0. 18. A process as claimed in any of claims 1 to 17 in which the - 53 43431 isocyanate prepolymer contains from 1.8 to 4.0% of isocyanate groups in the solid prepolymer. 19. A process as claimed in claim 1 substantially as herein described with reference to any of the Examples. 20. A shaped polyurethane product which can be self-crosslinked by methylolether groups, which has been obtained by chain-lengthening a substantially linear isocyanate prepolymer obtained from a dihydroxy compound and excess organic diisocyanate, in a solvent and forming the shaped product from the resultant solution, in which product is contained a monomethylolether diol of the formula HO—R—N-R-OH (NH) (I) I x O=CNH-CH 2 — or in which R represents a straight or branched chain alkylene group: R‘ represents an alkyl group and x represents 0 or 1 built into the isocyanate prepolymer. 21. A shaped polyurethane product as claimed in claim 20 when prepared by a process as claimed in any of claims 1 to 19 22. A shaped polyurethane product which has been self-crosslinked by a methylolether, produced by chain lengthening a substantially linear isocyanate prepolymer obtained from a dihydroxy compound and excess organic diisocyanate, and which has been modified by incorporating a monomethylolether diol of the formula HO—R—N—R-OH O=CNH—CH 2 —OR' in which R represents a straight or branched chain alkylene group; - 54 4 3 431 R' represents an alkyl group and x represents 0 or 1, in a solvent, forming a shaped product from the resulting solution and cross-linking the product after shaping. 5 23. A shaped polyurethane product as claimed in claim 22 which has been produced by a process as claimed in any of claims 1 to 19. 24. A shaped polyurethane product as claimed in claim 22 or 23 which has been produced by the self-cross-linking of a

15. To any of the Examples.