Isocyanate adduct diols of the formula EQU M--CO--NH--D'--NH--CO--A in which M is derived from an amino diol or a hydrazino diol, D' represents the divalent radical of an organic diisocyanate, and A is an isocyanate masking group; and a process for their production.

This invention relates to isocyanate adduct diols, to their production and 
to their use for the production of self-crosslinkable and/or 
self-crosslinked polyurethanes. 
Substantially linear "segmented" polyurethane elastomers have recently 
acquired considerable significance. They are preferably used in the form 
of solutions in highly polar solvents and are of particular importance for 
spinning into polyurethane elastomer filaments, for the coating of 
textiles, for the production of films and for the manufacture of 
microporous films or artificial leather products. 
The stringent requirements which materials such as these, particularly 
elastomer filaments, have to satisfy can only be satisfied by suitably 
selecting corresponding starting materials and reaction parameters. The 
"segment structure" of these substantially linear polyurethanes performs a 
considerable function in that, for example, the elasticity is largely 
determined by the relatively long chain "soft segments" (dihydroxy 
compounds) whereas the softening point and melting range, resistance to 
strain at elevated temperatures or in hot water, modulus and strength are 
largely determined by the so-called "hard segments" of diisocyanate and 
chain extenders (cf. Chemiker-Zeitung 98, (1974), pages 344-353). The 
properties of the elastomers are critically determined by the symmetry of 
the hard segments and by an optimum physical aggregation via hydrogen 
bonds (H-bond crosslinks) between a plurality of individual hard segments. 
This "physical crosslink" through H-bonds may readily be dissolved, for 
example by highly polar solvents which solvate the hard segment (for 
example dimethyl formamide), in addition to which the binding force 
decreases relatively quickly with increasing temperatures. 
Accordingly, attempts have repeatedly been made to improve the properties 
of the elastomers by additional chemical crosslinking, for example by the 
addition of polyisocyanates, polyethylene imine derivatives, epoxides or 
polyformaldehyde derivatives, such as polymethylol or polymethylol ether 
derivatives. In this connection, it was found that subsequent chemical 
crosslinking of the polyurethanes by the addition of the above compounds 
can be obtained with insolubilisation and, optionally, in improvement in 
certain elastic properties, but only at the expense of more important 
service properties, particularly the thermal and hydrothermal properties. 
In addition, the temperatures required to initiate crosslinking may be too 
high or the crosslinking rate too low for practical purposes. 
Particularly important service properties are, for example, the behaviour 
of the filaments under tension or elongation in hot water, for example 
under dyeing and finishing conditions. They also include the "flow" range 
of the filaments under predetermined tension on exposure to high 
temperatures, for example during heat-fixing, and the behaviour of the 
filaments in elastic knitted fabrics under the conditions of "thermal 
forming" where high elongations and high temperatures are applied. 
This new process technique, in which bra cups for example of knitted 
polyamide/elasthane fabrics are thermally formed (at around 190.degree. to 
195.degree. C.) instead of being machine-stitched, imposes particularly 
critical conditions on the thermal behaviour of elastomeric filaments. 
An object of the present invention is to provide isocyanate adduct diols 
which are suitable for the production of polyurethane elastomers of the 
type which 
(a) are chemically crosslinked or are self-crosslinkable, 
(b) contain the crosslinking group in a particular form and hence influence 
the thermal and hydrothermal properties much more favourably than is the 
case where conventional crosslinking agents are added, 
(c) have improved thermal formability, and 
(d) show improved resistance to hydrolysis, improved resistance to 
solvents, improved resistance to thermal degradation and, optionally, 
reduced surface adhesion. 
The crosslinking reactions with the urethane, preferably urea, segments are 
intended to be readily initiatable by heat, not to require the presence of 
specific groups (for example tertiary amines) and, in regard to the onset 
of crosslinking (for example insolubility of the products) to be active 
with even smaller incorporated quantities than is the case where external 
crosslinking agents are added. 
Other desirable and accomplished improvements will become apparent from the 
description and the Examples. 
The present invention provides isocyanate adduct diols corresponding to the 
formula: 
EQU M--CO--NH--D'--NH--CO--A 
in which 
M is derived from an amino diol or hydrazino diol, 
D' represents the divalent radical of an organic diisocyanate, and 
A represents an isocyanate masking group. 
The isocyanate adduct diols are suitable for the production of solutions of 
self-crosslinkable polyurethanes obtained by reacting a substantially 
linear NCO-prepolymer of relatively long chain dihydroxy compounds having 
a molecular weight of from about 600 to 6000, optionally in the presence 
of low molecular weight diols, and excess quantities of organic 
diisocynates and chain extenders in solvents with low molecular weight 
compounds, such as diols or water, but particularly with N-H-active 
terminal groups, such as diamines, aminoalcohols, dihydrazide compounds 
and hydrazine, having molecular weights of from 32 to about 400, by 
incorporating isocyanate adduct diols corresponding to the formula: 
EQU M--CO--NH--D'--NH--CO--A 
in which 
M is derived from an amino diol or hydrazino diol, 
D' represents the divalent radical of an organic diisocyanate, and 
A is an isocyanate masking group, 
into the NCO-prepolymers in quantities of from 0.1 to 10% by weight and 
preferably in quantities of from 0.25 to 5.0% by weight, based on the 
solids content. 
Accordingly, the present invention also relates to the use of the 
isocyanate adduct diols for the production of spontaneously crosslinkable 
and/or crosslinked polyurethanes. For example, solutions of spontaneously 
crosslinkable polyurethane may be processed into spontaneously crosslinked 
polyurethane-based shaped articles in the form of filaments, films or 
coatings. 
The distinct improvement in the properties of the shaped articles thus 
produced may possibly be explained by the fact that, in this case, the 
crosslinking reaction between two linear segmented polyurethane molecule 
chains takes place through branching or crosslinking points in different 
regions of the molecule. Thus, one potential crosslinking point is 
incorporated as the isocyanate donor diol in controllable form into the 
actual so-called "soft segment" in the so-called NCO-prepolymer (see 
formula scheme A), whilst the other crosslinking point arises out of the 
reaction of the isocyanate donor group with, in general, the "urea hard 
segment". In this case, therefore, a crosslinking reaction is obtained by 
preferential reaction with only one hard segment. 
During the reaction of the NCO-donor group with urethane groups within the 
soft segment, which cannot be ruled out as a minor reaction, the only 
crosslinking reaction which is initiated is a basically particularly 
desirable crosslinking between soft segments. 
However, the known addition of diisocyanates or polyisocyanates or 
polyisocyanate donors leads to the chemical reaction in two or more 
different hard segments. Thereafter, both the statistical distribution of 
the crosslinking points and also the multiple chemical substitution in 
several hard segments are less favourable. The latter can evidently affect 
the physical "crosslink" through H-bonds so seriously that, despite the 
increase in the number of chemical crosslinking bonds, the number of 
physical crosslinking bonds is overproportionally reduced. This is 
reflected in the deterioration of a number of properties. 
The isocyanate donor diols (a) may be incorporated into the soft segment of 
the NCO-prepolymers by the methods normally used for the production of 
prepolymers, for example by using the NCO-donor diols in the reaction of 
the relatively high molecular weight dihydroxy compounds: 
______________________________________ 
HO--G--OH (G = radical of the relatively high 
molecular weight dihydroxy compound) 
______________________________________ 
with excess quantities of diisocyanates 
______________________________________ 
OCN--D--NCO (D = radical of the diisocyanate) 
______________________________________ 
to form the NCO-prepolymer having the idealised structure according to 
formula scheme A: 
##STR1## 
The crosslinkable modified NCO-prepolymer behaves in virtually the same way 
as an unmodified NCO-prepolymer. The chain extending reaction with 
diamines, for example, results in the formation of the typical hard 
segment: 
EQU --NH--CO--NH--Y--NH--CO--NH-- 
which, through its interaction via hydrogen bonds with a large number of 
adjacent hard segments, forms blocks of hard segments physically 
crosslinked with one another and provides the polymer with its typical 
elastic properties. 
This hard segment is the preferred starting point for the chemical 
crosslinking reaction with the isocyanate donor group. 
Preferred isocyanate adduct diols are those corresponding to the general 
formula: 
EQU M--CO--NH--D'--NH--CO--A 
in which M represents the radical 
##STR2## 
in which R.sub.1 and R.sub.2 may be the same or different and represent a 
straight-chain or branched alkylene radical containing up to 12 carbon 
atoms or a cycloalkylene radical, and x=0 or 1. More particularly, the 
invention relates to isocyanate adduct diols corresponding to the general 
formula: 
EQU M--CO--NH--D'--NH--CO--A, 
in which the radical M corresponds to the formula: 
##STR3## 
where R.sub.1 represents the radical 
##STR4## 
with R.sub.3 =hydrogen or C.sub.1 -C.sub.3 --alkyl, particularly methyl, 
R.sub.2 represents a straight-chain or branched alkylene radical 
containing up to 12 carbon atoms or a cycloalkylene radical, and 
x=0. 
In addition, preferred crosslinkers are those corresponding to the general 
formula: 
EQU M--CO--NH--D'--NH--CO--A, 
in which the radical M corresponds to the general formula: 
##STR5## 
in which R.sub.1 and R.sub.2 may be the same or different and represent a 
straight-chain or branched alkylene radical containing up to 12 carbon 
atoms or a cycloalkylene radical, and R.sub.4 represents hydrogen and/or 
C.sub.1 -C.sub.4 --alkyl, particularly methyl. 
The isocyanate adduct diols according to the invention consist in principle 
of the components: 
(1) amino diols or hydrazino diols, 
(2) organic diisocyanates OCN--D'--NCO, and 
(3) "donors" AH. 
In principle, the amino diols or hydrazino diols may be any diols which 
contain another secondary or primary amino group. 
One readily accessible group is the alkoxylation products of ammonia or 
hydrazine: 
##STR6## 
for example and, preferably, bis-(.beta.-hydroxyethyl)-amine, 
bis-(.beta.-hydroxypropyl)-amine, 
(.beta.-hydroxyethyl)-.beta.-hydroxypropylamine, 
bis-(.beta.-hydroxybutyl)-amine or 
N,N-bis-(.beta.-hydroxyethyl)-hydrazine, N,N-bis-(.alpha.-hydroxypropyl)-h 
ydrazine and N,N-bis-(.beta.-hydroxybutyl)-hydrazine. 
Another suitable group are, for example, the monoalkoxylation products of 
aminoalkanols or aminocycloalkanols, preferably corresponding to the 
formula: 
##STR7## 
in which R.sub.2 and R.sub.3 are as defined above 
The following are particularly suitable: 
4-N-(.beta.-hydroxyethyl)-amino-1-butanol, 
6-N-(.beta.-hydroxyethyl)-amino-1-hexanol, 
6-N-(.beta.-hydroxypropyl)-amino-1-hexanol, 
12-N-(.beta.-hydroxyethyl)-amino-1-dodecanol, 
4-N-(.beta.-hydroxyethyl)-amino-1-cyclohexanol, 
3-N(.beta.-hydroxyethyl)-amino-1-cyclohexanol, or even other amino 
derivatives of diols, preferably those corresponding to the formula: 
##STR8## 
in which R.sub.1, R.sub.2 and R.sub.4 are as defined above. 
The following diols, for example, are preferably used: 2-amino-1,3-propane 
diol, 2-methylamino-1,3-propane diol, 2-amino-2-methyl-1,3-propane diol, 
2-amino-2-ethyl-1,3-propane diol, 3-amino-2,4-pentane diol, 
2-amino-1,5-pentane diol or 3-amino-2,5-dimethyl-2,5-hexane diol. 
The organic diisocyanates OCN--D'--NCO may be aliphatic or cycloaliphatic 
dissocyanates, although they are preferably aromatic diisocyanates, for 
example diphenyl methane-4,4'-diisocyanate, tolylene-2,4-diisocyanate, 
tolylene-2,6-diisocyanate, phenylene-1,3-diisocyanate, 
phenylene-1,4-diisocyanate, diphenyl ether-4,4'-diisocyanate and others, 
but preferably diphenyl methane and tolylene diisocyanates. 
Suitable donor compounds A-H are, in principle, any compounds of which the 
addition products with isocyanates show low thermal stability. Compounds 
such as these are, for example, phenols, acetoacetic esters, malonic 
esters, acetyl acetone, phthalimide, benzene sulphonamide, 
2-mercaptobenzthiazole or hydrocyanic acid (cf. Kunststoff-Handbuch, Vol. 
VII, Polyurethane, pages 11 to 14, Carl-Hanser-Verlag, Munich, 1966). One 
class of compounds which is particularly suitable and preferred for the 
purposes of the invention is the lactams, for example pyrrolidone, 
.alpha.-piperidone or caprolactam derivatives, for example 
.epsilon.-caprolactam, the methyl caprolactam isomers (for example 
.gamma.-ethyl caprolactam or .gamma.-tert.-butyl caprolactam). 
.epsilon.-Caprolactam itself is particularly preferred. 
The particular suitability of caprolactam was surprising because a 
relatively high splitting temperature is normally quoted in the literature 
(cf. High Polymers - Volume XVI - J. H. Saunders, K. C. Frisch, 
Polyurethanes - Part I - Chemistry, page 120; Interscience Publishers, 
1962). 
The ready crosslinkability lies in the selected incorporation structure of 
the diols of the type used in accordance with the invention which provides 
for a much more favourable crosslinking behaviour than the bis-caprolactam 
crosslinkers (diisocyanates+2.times.caprolactam) added in accordance with 
the prior art. 
The novel isocyanate donor diols may be produced by various methods (cf. 
Production Examples 1, 2, 5). 
For example, a bis-adduct may initially be prepared from the diisocyanate 
and two moles of donor (see, for example, formula I in Production Example 
1), and one of the donor groups may subsequently be replaced by reaction 
with one equivalent of monoamino diol (for example II). In general, the 
required compound is freed from crystallisation from I or even from the 
tetrakis-hydroxy derivative (see for example IX). 
Another approach is, for example, the process according to Example 5. 
In this case, one NCO group is reacted with one equivalent of caprolactam 
to form the monoadduct isocyanate (VI) which is then reacted with an 
equivalent quantity of amino diol to form the required product (for 
example VII or VIII). 
Accordingly, the invention also relates to processes for producing the 
isocyanate adduct diols according to the invention which are distinguished 
by the fact that an organic diisocyanate and one or two moles of a 
compound which is capable of forming an addition product of low thermal 
stability with a diisocyanate are reacted to form a mono- or bis-adduct 
which is subsequently reacted with a monoamino diol or hydrazino diol. 
Relatively high molecular weight dihydroxy compounds which may be used in 
the synthesis of the polyurethanes are compounds having molecular weights 
of from about 600 to 6000, preferably from 1000 to 3000, for example 
polyesters, polyethers, polylactone esters, polyacetals, polycarbonates, 
mixtures of these groups or co-condensates of these groups, for example 
polyester ethers, polyester lactone esters, polycarbonate esters and 
others having melting points preferably below 60.degree. C., more 
particularly below 50.degree. C., of the type which have been repeatedly 
described for the synthesis of the segmented polyurethane(urea) elastomers 
in question. 
Examples are adipic acid esters of 1,6-hexane diol, 2,2-dimethyl propane 
diol, 1,4-butane diol, 1,2-propylene glycol and ethylene glycol or 
polyesters of mixtures of diols for lowering the melting point of the 
polyester. Polypropylene glycol ethers, preferably polytetramethylene 
glycol ethers, give products having a high resistance to hydrolysis. 
Polycaprolactone (mixed) esters and hexane diol (mixed) polycarbonates and 
also adipic copolyesters with long-chain diols (for example 1,6-hexane 
diol) are also particularly preferred by virtue of their increased 
resistance to hydrolysis. 
For improving dyeability, diols containing tertiary amines, such as 
N-methyl-N,N-bis-(.beta.-hydroxyethylamine) or 
N-methyl-N,N-bis-(.beta.-hydroxypropylamine), may be used in quantities of 
from about 0.03 to 0.25 mole/kg during formation of the NCO-prepolymer 
(cf. German Offenlegungsschrift No. 1,495,830). 
The organic diisocyanates used may be known diisocyanates or their 
structural analogs, although it is preferred to use diphenyl 
methane-4,4'-diisocyanate , the isomeric tolylene diisocyanates, diphenyl 
ether-4,4'-diisocyanate and 1,6-hexane diisocyanate, dicyclohexyl 
methane-4,4-diisocyanate and 3-isocyanatomethyl-3,5,5-trimethyl 
cyclohexane isocyanate. 
The diisocyanates are reacted with the OH-containing compounds in excess 
quantities, preferably in a molar OH/NCO-ratio of from about 1:1.35 to 
about 1:3.0, to form the NCO-prepolymer, the NCO-prepolymer preferably 
containing from about 1.8 to 4.0% of NCO, based on the prepolymer solids. 
The NCO-prepolymer may be formed from the components, including the diol 
component I according to the invention, by methods known in principle 
either in the melt or preferably in solvents. 
For example, all the components may be simultaneously reacted in solvents, 
such as chlorobenzene, toluene, dioxane or, preferably, in highly polar 
dimethyl formamide or dimethyl acetamide, at temperatures of from about 
20.degree. to about 100.degree. C. to form the prepolymer, or 
alternatively an NCO-prepolymer may even be initially formed (either 
wholly or in part) from relatively long chain dihydroxy compounds and the 
isocyanate adduct diol subsequently reacted to form the final 
NCO-prepolymer containing the incorporated diol. The type of statistical 
distribution within the NCO-prepolymer may be influenced according to the 
procedure adopted. 
The isocyanate adduct diols are used in such quantities in the reaction by 
which the prepolymer is formed that approximately 0.1 to 10% by weight of 
the diols and preferably 0.25 to 5.0% by weight, based on the prepolymer 
solids, are incorporated. Since the weight of the chain-extending agent is 
only of minor importance, substantially the same incorporated quantity, 
based on the segmented poly(urea)urethane elastomer, may be assumed. A 
value which effectively characterises the crosslinking density is the 
number of --NH--CO--A--groups in mVal/kg because it indicates the 
equivalents of crosslinker groups incorporated. In the present case, the 
polyurethane should contain from about 5 to 500 mVal and preferably from 
about 20 to 200 mVal of crosslinker equivalents (see Examples). Naturally, 
excessively small quantities may not initiate the effect sufficiently; on 
the other hand, excessively high quantities of crosslinking groups are 
also unfavourable because numerous properties (for example elongation at 
break and modulus) are adversely affected in this way. Accordingly, 
incorporated quantities of from about 25 to 150 mVal of NCO-donor groups 
per kg of polyurethane are particularly preferred. 
The reaction by which the prepolymer is formed is preferably carried out in 
dimethyl formamide or dimethyl acetamide as solvent, at temperatures of 
from about 20.degree. to 60.degree. C. and over periods of from about 20 
to 200 minutes. 
The NCO-prepolymer formed, modified by incorporation, is then reacted with 
substantially equivalent quantities of bifunctional N-H-active compounds 
in highly polar solvents, such as dimethyl formamide, dimethyl acetamide 
or dimethyl sulphoxide, to form highly viscous solutions of the poly(urea) 
urethanes by the usual methods of chain extension known per se. In cases 
where 3-isocyanatomethyl-3,5,5-trimethyl cyclohexane isocyanate is almost 
exclusively used, it is also possible to use so-called bifunctional "soft 
solvents", for example toluene/isopropanol mixtures. 
The H-reactive chain extenders used are glycols or water, but preferably 
compounds having molecular weights of from about 32 to about 400, which 
contain NCO-reactive hydrogen attached to N-atoms and which correspond to 
the formula N.sub.2 H--Y--NH.sub.2, where 
Y=only one bond (.fwdarw.hydrazine), 
Y=a difunctional aliphatic, cycloaliphatic, aromatic, araliphatic or 
heterocyclic radical Z .fwdarw.diamine), 
Y=the group 
##STR9## 
where Z is as defined above, and 
X.sub.1 and X.sub.2 independently of one another represent a single bond, 
--O-- or --NH-- (i.e..fwdarw.dihydrazides, dicarbazinic esters, 
disemicarbazides, semicarbazide hydrazide, etc.), 
Y=the group 
##STR10## 
(where Z and X.sub.1 are as defined above), i.e..fwdarw.aminohydrazides 
and aminosemicarbazides, or 
Y=--NH--CO--NH-- (.fwdarw.carbodihydrazide). 
Examples of chain extenders corresponding to the formula H.sub.2 
N--Y--NH.sub.2 are as follows: hydrazine or hydrazine hydrate (cf. German 
Patent No. 1,161,007); primary and/or aliphatic, cycloaliphatic, aromatic 
or heterocyclic diamines, preferably ethylene diamine or 
1,3-diaminocyclohexane; 1,2-propylene diamine and/or m-xylylene diamine 
(cf. German Pat. No. 1,223,154; U.S. Pat. Nos. 2,929,804 and 2,929,803; 
German Auslegeschrift No. 1,494,714); amino alcohols, for example 
aminoethanol or 4-aminocyclohexanol; dihydrazides, for example 
carbodihydrazide; adipic acid hydrazide (cf. German Pat. Nos. 1,123,467 
and 1,157,386); aminocarboxylic acid hydrazides, such as aminoacetic acid 
hydrazide or .beta.-aminopropionic acid hydrazide (cf. German 
Auslegeschrift No. 1,301,569); semicarbazide hydrazides such as, for 
example, .alpha.-semicarbazidoacetic acid hydrazide or 
.beta.-semicarbazidopropionic acid hydrazide (cf. German Pat. No. 
1,770,591); or other known NH-compounds of the type described in the above 
publications and, for example, also in German Offenlegungsschrift No. 
2,025,616. 
However, particularly preferred chain extenders are ethylene diamine, 
1,2-propylene diamine, hydrazine, .beta.-aminopropionic acid hydrazide and 
.beta.-semicarbazido propionic acid hydrazide, relatively small quantities 
of so-called "co-extenders" being useable for modifying the properties 
(for example small quantities of 1,3-diaminocyclohexane or water in 
addition to ethylene diamine as the main extender). 
It is, of course, also possible to use relatively small quantities of 
monofunctional amino compounds, for example monoamines (diethylamine), 
monohydrazide derivatives (acethydrizide, picolinic acid hydrazide or 
butyl semicarbazide) and also asymmetrical dimethyl hydrazine, or very 
small quantities of trifunctional compounds (for example 
1,5,11-triaminoundecane) for increasing functionality (viscosity). 
The highly viscous elastomer solutions obtained may be formed by 
conventional methods, for example by coating onto substrates and 
evaporating off the solvent to leave highly elastic films and foils, by 
knife-coating onto textile substrates to form textile coatings, by 
coagulating solutions (optionally with the addition of a non-solvent) to 
form microporous films for artificial leather or, preferably and 
particularly importantly, by spinning the solutions to form elastomeric 
filaments. 
One advantage of the spontaneously crosslinkable polyurethane systems is 
that, even in the case of wet coagulation and wet spinning processes, 
there is no danger of the crosslinker being washed out with the solvent or 
being reduced in its concentration. This is also of particular interest in 
coagulation processes for artificial leather where a coagulation step in 
mixtures of dimethyl formamide and water, followed by washing, would 
result in a loss of additive crosslinkers. 
The high stability of the solution containing the self-crosslinkable 
polyurethanes against undesirable premature crosslinking in solution is 
particularly favourable. The solutions can be kept ready for processing 
for weeks without crosslinking. In some cases, the polyurethane mouldings 
can also be obtained in uncrosslinked form. For example, elastomeric 
filaments may be spun and processed in uncrosslinked form. It is only at 
the specific application stage, for example the thermal forming of the 
knitted fabrics of polyamide/elasthane filaments, that the crosslinking 
reaction begins at the activation temperature and prevents, for example, 
the degradation or breaking of the filaments in the knitted fabric. 
Depending upon the forming conditions (mainly the forming temperatures), 
the mouldings obtained are either uncrosslinked (at low temperatures, for 
example below 100.degree. to 110.degree. C.) or partially or completely 
crosslinked (at high temperatures and/or with relatively long heating 
times). In general, the crosslinking reaction will be controlled in 
accordance with the process and the particular application envisaged. 
Heating may be carried out relatively slowly, for example in the case of 
filaments wound into package form over a period of from 20 to 120 minutes 
at around 120.degree. to 150.degree. C., or more quickly, for example in 
the case of coatings over a period of from 1 to 5 minutes at around 
130.degree. to 180.degree. C. in drying tunnels or on high-temperature 
treatment units, such as heating godets or heating grooves where the 
surface or rather air temperatures can amount for example to between 
160.degree. to 250.degree. C. with short contact times of from about 0.5 
to 10 seconds. With very short contact times, the temperatures may be even 
higher (for example by using infrared heating systems). 
There is no need to use catalysts for the crosslinking reaction, although 
catalysts may be present in cases where it is desired to accelerate the 
crosslinking reaction. Suitable catalysts are in principle any known 
accelerators for the isocyanate reactions employed in the usual 
quantities. 
EXPLANATION OF THE MEASURING TECHNIQUES AND MEASURING PROCEDURES ADOPTED IN 
THE EXAMPLES: 
Unless otherwise stated, the parts quoted in the Examples represent parts 
by weight. 
The molecular weight of the polyurethane elastomer is characterised by the 
(.eta.).sub.i -value, the so-called inherent viscosity, 
##EQU1## 
where .eta. r is the relative viscosity of a solution of the polymer in 
hexamethyl phosphoramide at 20.degree. C., and c is the concentration in 
g/100 ml of solution. The measurements were carried out with a c-value of 
1. 
A high .eta..sub.i -value and the insolubility of the mouldings 
(corresponding to .eta..sub.i .fwdarw..infin.) characterise a high 
resistance to thermal degradation, as required for heat-fixing and, in 
particular, for the thermal forming process described above. 
The filaments or films were tested for their elastic properties by the 
measuring techniques described in Belgian Pat. No. 734,194, according to 
which elongation at break is measured in a tension tester in which the 
length between the clamps is controlled by a photocell and in which the 
particular degree of slip through the clamps is compensated. 
The elastic values are characterised by measuring the modulus at 300% (in 
the first elongation curve), the modulus at 150% (in the third recovery 
curve) and also the permanent elongation (after three times 300% with 
elongation rates of 400% per minute, 30 seconds after relaxation). 
Determination of hot-water extension 
A 50 mm long piece of filament is stretched by means of an extending device 
controlled through a force-measuring head until a contraction stress of 
0.25 mN/dtex is applied by the filament. This strain is maintained, 
optionally by continuously increasing the stretching force, and the degree 
of extension is determined in air after 25 minutes under load (first 
value). Thereafter, the stretched filament is immersed in water at 
95.degree. C. with the load intact and the total extension occurring is 
read off after another 25 minutes under load in water (second value). In a 
third step, the stretched filament is removed from the water, relaxed 
until it begins to lose tension and the degree of residual elongation is 
determined (third value). All the measured values are expressed in % of 
the length between the clamps in accordance with the following scheme: 
______________________________________ 
1st value 2nd value 3rd value 
______________________________________ 
Extension in air 
Extension in Residual elongation 
at 20.degree. C. after 25 
water at 95.degree. C. 
after complete 
minutes under a 
after 25 minutes 
relaxation in air 
load of under a load of 
at 20.degree. C. 
##STR11## 
##STR12## 
[%] [%] [%] 
______________________________________ 
The hydrothermal properties may be rated more highly, the lower the second 
value (extension in hot water in relation to the first value) and the 
lower the third value (permanent extension after relaxation). 
Determination the reduction in tension in hot water (RTHW) of elastomeric 
filaments 
A piece of filament with a length between the groups of 100 mm (biasing 
weight 0.009 mN/dtex) is stetched by 100% at 20.degree. C. and the 
filament tension obtained after 2 minutes (mN/dtex) is measured (first 
value). The filament still stretched by 100% is then immersed in water at 
95.degree. C. and the tension obtained after a residence time of 3 minutes 
is determined (second value). After this measurement, the filament is 
removed frm the water bath and left standing for 2 minutes at room 
temperature. Thereafter, the filament still stretched between the clamps 
is relaxed until free from tension and the degree of residual elongation 
is measured (third value). Plan of reproduction in the Examples 
(abbreviation RTHW): 
______________________________________ 
RTHW 
______________________________________ 
Tension in Tension in Residual elongation 
air at 20.degree. C. 
water at 95.degree. C. 
after relaxation 
(in mN/dtex) 
(in mN/dtex) (in %) 
______________________________________ 
The hydrothermal properties may be rated more highly, the higher the second 
value (tension in hot water in mm/dtex) and the lower the third value 
(residual elongation after treatment in relaxed form). 
Determination of the heat distortion temperature (HDT) of elastomeric 
filaments 
The denier of elastomeric filaments is determined after exposure for 3 
hours in the absence of tension to standard room conditions (by weighing a 
piece of filament under an initial load of 0.003 mm/dtex). An elastomeric 
filament with a length between the clamps of 250 mm is suspended at room 
temperature in a nitrogen-filled glass tube under an initial load of 0.018 
mm/dtex. The tube is surrounded by a heating jacket through which 
circulates silicone oil heated using a thermostat. The temperature in the 
tube is initially increased to around 125.degree. C. over a period of 
about 30 minutes. The temperature is further increased at a rate of 
2.1.degree. C. per minute until the elastomeric filament has undergone a 
change in length of more than 400 mm. 
The change in temperature (abscissa value) and extension of the test 
specimen (ordinate value) are recorded by means of an X-Y-recorder in such 
an axis ratio that a gradient in the measuring curve of 45.degree. is 
reached for a relative change in length .gamma. of 0.8% per degree of 
temperature increase. 
##EQU2## 
The heat distortion temperature (HDT) is the temperature which is read off 
by a vertical projection to the abscissa of the point of contact of the 
45.degree. tangent to the temperature/length change curve. 
In general, the thermal stability of the elastomers may be rated more 
highly, the higher the HDT-value measured. 
Determination of the hot break time (HBT) of elastomeric filaments 
A piece of elastomeric filament is clamped between two clamps (interval 10 
cm), stretched by 100% and placed in this form on a 4 cm wide 
chromium-placed metal plated heated by a thermostat to 193.degree. C. The 
filament either breaks after a certain residence time or remains stable. 
After a measuring time of around 3 minutes, the test is terminated if the 
filament remains intact (characterisation: &gt;180 seconds). The HBT-values 
are expressed in seconds (sec.) representing the period after which the 
stretched filaments are seen to break at a temperature of 193.degree. C. 
This measurement was developed from a simulation of the behaviour of the 
filaments in a knitted fabric of polyamide and elasthane filaments. It was 
found that basically the same results are obtained when a loop of 
polyamide-6filament is measured against a loop of elasthane filament 
(simulation of the stitches) as when the above simplified measuring 
technique is adopted. 
The behaviour of elasthane filaments during thermal forming (extensions per 
unit area of around 50 to 100%; forming temperatures around 180.degree. to 
200.degree. C.) may be correlated relatively well in accordance with the 
results of the HBT-meausurements.

The following examples are to further illustrate the invention without 
limiting it. 
EXAMPLE/PRODUCTION SPECIFICATION 1 
In accordance with the reaction equation: 
##STR13## 
74 g (0.5 mole) of N,N-bis-(2-hydroxypropyl)-hydrazine (II) and 0.5 part 
of water are introduced at 105.degree. C. into a solution of 476 g (1 
mole) of the bis-caprolactam adduct (I) and 2 liters of toluene. The 
solution is then heated under reflux for 45 minutes, after which another 
2.5 liters of toluene are added to it, followed by storage overnight in a 
refrigerator. The crystallisate formed is filtered off under suction, 
washed with a little cold toluene and freed in vacuo from the adhering 
solvent. The crude product (356) is stirred up in 1 liter of methanol at 
40.degree. to 45.degree. C., after which the insoluble fractions of the 
starting material (I, 233 g, m.p. approximately 174.degree. C.) are 
filtered off. 
2.5 parts of water are added to the filtrate and the crystallisate (III) 
which has accumulated after 24 hours is filtered off under suction. Yield: 
104 g (33 % of the theoretical amount),m.p. 151.degree. to 154.degree. C. 
N calculated: 13.69%, N observed: 13.57%. 
The adduct (I) of 2 moles of caprolactam and 1 mole of diphenyl 
methane-4,4'-diisocyanate is obtained in the form of a highly crystaline 
substance by reacting 250 g of diisocyanate with 254 g of 
.epsilon.-caprolactam under nitrogen in the melt at 100.degree. C. 
(strongly exothermic reaction), followed by recrystallisation from boiling 
toluene. Yield: 372 g, m.p.: 178.degree.-180.degree. C. 
The diol adduct (IV) can be correspondingly isolated by reacting 1 mole of 
bis-caprolactam adduct (I) with 1 mole of N,N-bis-2-hydroxyethyl 
hydrazine: 
##STR14## 
EXAMPLE/PRODUCTION SPECIFICATION 2 
238 g (0.50 mole) of the bis-caprolactam adduct (I) are dissolved in 1 
liter of boiling toluene and the resulting solution is heated under reflux 
for 45 minutes with 26 g of diethanolamine (0.25 mole) and 0.25 ml of 
water. 
After cooling, the solvent is distilled off in vacuo, the solid residue is 
stirred in 1 liter of methanol at 40 .degree.to 45.degree. C. and the 
residue (bis-adduct-I) is isolated by filtration. The methanolic solution 
is precipitated in 1500 ml of water. 
The residue is suspended in and digested with ether. The residual solid 
(V), m.p. 135.degree.-143.degree. C., is recrystallised from 
chlorobenzene.fwdarw.m.p. 146.degree.-148.degree. C. 
##STR15## 
EXAMPLE 3 
500 parts of a 1,6-hexane diol/2,2-dimethyl-1,3-propane diol/adipic acid 
polyester (molar ratio of the diols 65:35) having a molecular weight of 
1875, 10.68 parts of N-methyl-bis-(.beta.-hydroxypropyl)-amine, 37.2 parts 
of the diol-NCO-adduct (III) (corresponding to 100 mVal of NCO/caprolactam 
crosslinker groups per kg of elastomer), 163.3 parts of diphenyl 
methane-4,4'-diisocyanate and 178 parts of dimethyl formamide are reacted 
to 1 hour at 50.degree. C. to form the NCO-prepolymer (2.79 % of NCO in 
the solid substance). 
6.85 parts of ethylene diamine are dissolved in 1230 parts of dimethyl 
formamide and converted with 10 parts of dry ice into the carbamate 
suspension. 400 parts of the prepolymer solution are added with intensive 
stirring to the carbamate suspension, resulting in the formation of an 
elastomer solution with a viscosity of 250 poises. 6 ml of a solution of 
6.70 parts of hexane diisocyanate in 50 parts of dimethyl formamide are 
added dropwise to the elastomer solution thus formed, resulting in the 
formation of a viscous homogeneous elastomer solution having a viscosity 
of 445 poises. The elastomer solution is spun by the dry spinning process. 
Portions of the solution are diluted to 16% and are wet spun and cast to 
form films. The films can still be smoothly dissolved after a drying time 
of 30 minutes at 70.degree. C. plus 30 minutes at 100.degree. C. After 
heating for 30 minutes to 130.degree. C., the film is insoluble in 
dimethyl formamide, even on heating to 80.degree. C. 
The film has a strength of 0.64 cN/dtex, an elongation of 597%, a modulus 
at 300% elongation of 0.11 cN/dtex and a heat distortion temperature (HDT) 
of 190.degree. C. 
Like the film, the wet-spun filaments can be subsequently crosslinked by 
heating (for example for 30 minutes to 130.degree. C.), after which they 
are insoluble in DMF. 
Testing of dry-spun elastomer filaments which have been aftertreated for 1 
hour at 130.degree. C. on bobbins shows that the filaments have become 
insoluble and have a hotbreak time of &gt;180 seconds at 193.7.degree. C. and 
100% elongation (the measurements are normally terminated after 180 
seconds). Further testing failed to show any breaks even after 420 
seconds. By contrast, elastomer filaments with the same composition, but 
without any crosslinking agent incorporated in them, break after only 
about 15 to 30 seconds. 
Accordingly, the advantages of the crosslinking process according to the 
invention lie both in the insolubilisation obtained and, more 
particularly, in the considerably improved hot break time. 
EXAMPLE 4 
400 parts of the polyester described in Example 3 (molecular weight 1875), 
8.29 parts of N-methyl-bis-(.beta.-hydroxypropyl)-amine, 28.8 parts of the 
diol-NCO-adduct (III) (corresponding to approximately 100 mVal of NCO 
-/Cl-crosslinker groups per kg of elastomer substace), 116.7 parts of 
diphenyl methane-4,4'-diisocyanate and 138 parts of dimethyl formamide 
(DMF) are converted into prepolymer after 85 minutes at 40.degree. to 
43.degree. C. (2.11% of NCO, based on solids - i.e. the prepolymer 
contains fewwer NCO-groups than in Example 1 and, hence, also less "hard 
segment" in the polyurethane). 
5.48 parts of ethylene diamine in 1070 parts of dimethyl formamide are 
converted with 10 g of CO.sub.2 into the carbamate (H.sub.3 N.sup..sym. 
-CH.sub.2 -CH.sub.2 -COO.sup..crclbar.), reacted while stirring with 450 
parts of the NCO-prepolymer and diluted with 305 parts of dimethyl 
formamide to c=20%/242 poises. By adding 1.14 parts of hexane diisocyanate 
in 10 parts of dimethyl formamide, the viscosity of the solution increases 
to 415 poises. The solution is dry spun (see below), wet spun and 
converted into films by drying (for 70 mins. at 100.degree. C.). 
COMISON EXAMPLE 
An NCO-prepolymer is prepared in the same way as described in Example 4, 
but without the incorporation of the diol-crosslinker-adduct III 
(NCO-content 2.10 % NCO), and the chain-extending reaction is carried out 
with ethylene diamine. An elastomer solution having a viscosity of 661 
poises (22 % solution) is obtained. 
If the films are cast and dried for 70 mins. at 100.degree. C., the films 
from both solutions are still soluble in DMF. After heating for 30 minutes 
at 130.degree. C., the film of the self-crosslinkable elastomer solution 
according to Example 4 has become insoluble in DMF. The film according to 
comparison tests remain soluble. 
If the solutions are wet spun in 90/10 mixtures of water/DMF heated to 
80.degree. C. and the filaments thus obtained are subsequently dried for 
20 minutes at 130.degree. C., it is again only the self-crosslinkable 
substance according to the invention which has become substantially 
insoluble, the properties of the filaments being considerably improved as 
a result of crosslinking, particularly in their thermal properties (for 
example the heat distortion temperature (HDT) and the hot break time at 
193.7.degree. C./100% elongation): 
______________________________________ 
Perm- HBT 
anent (sec. at 
Tensile 
Elong- elong- 193.7.degree. C./ 
strength 
ation ation HDT 100% 
cN/dtex 
% % .degree.C. 
elongation) 
______________________________________ 
According 
to the 
invention 
0.64 562 16 181 .gtoreq.180 
(Example 
4) 
Comparison 
test 0.59 565 19 176 14.9 
______________________________________ 
If, instead of III, the diol-crosslinker adduct IV is used in an equivalent 
quantity in Example 4, the same crosslinking and, hence, improvement in 
properties is obtained. 
EXAMPLE 4b 
200 parts of a polyester corresponding to Example 3 (molecular weight 
1950), 12.48 parts of the monoadduct diol IV (100 mVal of crosslinker per 
kg of elastomer), 49.26 parts of diphenyl methane-4,4'-diisocyanate and 66 
parts of dimethyl formamide are reacted to 180 minutes at 42.degree. C. to 
form the NCO-preadduct (2.21% of NCO in the solid substance). 
For the chain-extending reaction, 107.5 parts of the above NCO-prepolymer 
solution are stirred into a suspension of 1.36 parts of ethylene diamine 
in 224 parts of dimethyl formamide and 3 parts of dry ice. A clear, 
homogeneous elastomer solution having a viscosity of 346 poises is formed. 
Films of this solution (dried for 70 minutes at 100.degree. C.) are soluble 
in dimethyl formamide. After heating (for 30 minutes at 130.degree. C.), 
the films are insoluble in dimethyl formamide and have a hot break time 
(HBT) at 193.7.degree. C./100% elongation of 208 seconds. (By contrast, 
crosslinker-free films show hot break times of only about 15 seconds and 
remain soluble; after heating at 130.degree. C., they even show a 
reduction in molecular weight of around 10%). 
If the crosslinker-containing but still soluble films (dried for 70 minutes 
at 100.degree. C.) are measured for their hot break time, they crosslink 
during the measurement and give a heat distortion temperature (HDT) of 
185.degree. C. which is high for their relatively low NCO-content. 
EXAMPLE/Production Specification (5) 
113 parts of .epsilon.-caprolactam (CL), 174 parts of 
tolylene-2,4-diisocyanate and 420 parts of petroleum ether are dissolved 
at 50.degree. C. and heated for 65 minutes to 60.degree. C. The solution 
separates increasingly into two phases which are separated in a separation 
funnel. The lower phase is washed three times with 50 ml of petroleum 
ether, after which its NCO-content is titrimetrically determined. 
300 ml of acetone are added to this layer which contains the CL-monoadduct 
isocyanate (VI), after which a quantity of diethanolamine equivalent to 
the NCO-content (based on the secondary amino group) is added dropwise 
while stirring and cooling with ice (internal temperature kept below 
20.degree. C. by cooling). The solution is then poured into 1 liter of 
water with precipitation of VII, the supernatant liquid is decanted off 
and the greasy deposit is dried in vacuo at 40.degree. to 50.degree. C. 
144 parts of a white, powdery product VII, m.p. 130.degree. C. (sint. 
105.degree.-110.degree. C.) are isolated. 
______________________________________ 
Analysis (VII): 
calculated: observed: 
______________________________________ 
C. 58.3 58.8% 
N 14.3 14.3% 
H 7.2 7.2% 
O 20.0 19.8% 
______________________________________ 
If, instead of diethanolamine, an equivalent quantity of 
2-amino-2-methyl-1,3-propane diol is used in the reaction with the 
CL-monoadduct isocyanate VI, the product VIII is obtained (m.p. 
132.degree. to 138.degree. C.). 
##STR16## 
The tetra-kis-hydroxy urea IX expected as a secondary product was produced 
from 1 mole of tolylene-2,4-diisocyanate and 2 moles of diethanolamine in 
dimethyl formamide solution at 0.degree. to 5.degree. C. and precipitated 
by the addition of a large quantity of acetone (m.p. 143.degree. C., white 
powder). 
##STR17## 
The same reaction of tolylene diisocyanate with 
2-amino-2-methyl-1,3-propane diol also gives the tetra-kis-hydroxy urea, 
m.p. 197.degree. to 200.degree. C. 
To produce the bis-caprolactam adduct (X) of tolylene diisocyanate, a 
mixture of equivalent quantities of the starting materials is heated to 
90.degree. C., after which exothermic heating to about 140.degree. C. 
occurs. The product is heated for another 2 hours to 90.degree. C. The 
product is recrystallised from 2 liters of toluene, m.p. 
170.degree.-173.degree. C. 
##STR18## 
EXAMPLE 6 
500 parts of an adipic acid/1,6-hexane diol/2,2-dimethyl-1,3-propane diol 
polyester (molecular weight 1950), 27.82 parts of the monoadduct diol VII 
(100 mVal of crosslinker groups per kg of polyurethane), 10.43 parts of 
bis-(.beta.-hydroxypropyl)-methylamine, 177.5 parts of diphenyl 
methane-4,4'-diisocyanate and 174 parts of dimethyl formamide are reacted 
for 80 minutes at 40.degree. C. to form the NCO-prepolymer (2.82% of NCO 
in the solid substance). 
420 parts of the NCO-prepolymer are introduced with intensive stirring into 
a suspension of 6.90 parts of ethylene diamine in 1080 parts of dimethyl 
formamide and 10 parts of dry ice, resulting in the formation of a clear, 
homogeneous and highly viscous elastomer solution (520 poises). 
Comparison Example (a)--no crosslinker incorporated--no addition 
An elastomer solution is prepared in the same way from the same starting 
materials, but without the incorporation of the crosslinker diol VII. The 
corresponding NCO-preadduct has an NCO-content (in the solid substance) of 
2.80%. The chain-extended polyurethane solution has a viscosity of 640 
poises/22% (or 328 poises/20%). 
Comparison Example (b)--without incorporation of crosslinker, but with 
addition of 100 mVal of bis-crosslinker X per kg of polyurethane. 
250 parts of the 22% crosslinker-free elastomer solution according to 
Comparison Example (a) are stirred with 1.15 parts of the bis-caprolactam 
adduct X ("bis-crosslinker") and 25 parts of dimethyl formamide (320 
poises). 
Comparison Example (c)--without incorporation of crosslinker, but with 
addition of 200 mVal of X/kg of polyurethane. 
250 parts of the elastomer solution a are stirred with 2.3 parts of X and 
30 parts of dimethyl formamide (306 poises). 
Comparison Example (d) 
If an attempt is made to incorporate an NCO-prepolymer corresponding to the 
Example, but with the incorporation of an equivalent quantity of the 
tetra-kis-hydroxy urea IX (instead of the monoadduct-crosslinker diol 
VII), complete crosslinking of the prepolymer occurs during the actual 
formation of the prepolymer. 
Approximately 0.12 mm thick films are cast from the solutions of the 
Example according to the invention and Comparison Examples a and c and 
dried (for 45 minutes at 70.degree. C.+45 minutes at 100.degree. C.). All 
the films were soluble in cold dimethyl formamide. 
The films are additionally heated to 30, 60, 120 and 180 minutes at 
130.degree. C. 
The film according to comparison test (a) remains soluble (no possibility 
of crosslinking). 
The films according to comparison tests (b) and (c) remain soluble, i.e. 
uncrosslinked, after 30, 60 and 120 minutes at 130.degree. C. and are only 
slightly crosslinked after 3 hours at 130.degree. C. (substantially 
soluble in cold DMF). Even after 1 hour at 150.degree. C., films (b) and 
(c) are uncrosslinked so that they remain soluble in dimethyl formamide 
heated to 95.degree. C. (they only undergo pronounced swelling in cold 
DMF). By contrast, the film according to the invention is crosslinked 
after only 30 minutes at 130.degree. C. and is still insoluble in dimethyl 
formamide, even after 20 minutes at 95.degree. C. 
The Example demonstrates the advantage of the self-crosslinkable structure 
incorporated compared with the "bis-caprolactam donors" or rather 
"crosslinkers" known per se. 
If the solutions are wet spun through 20-bore spinnerets 0.12 mm in 
diameter into a coagulation bath heated to 80.degree. C. of water and 
dimethyl formamide (90/10), and if the filaments thus formed are wound 
into package form at a speed of about 5 meters per minute, followed by 
treatment in a water bath at 50.degree. C. and then at 90.degree. C. to 
remove the solvent, drying in air and tempering for 1 hour at 130.degree. 
C., the following results are obtained: 
__________________________________________________________________________ 
Hot break 
time at 
Denier 
Strength 
Elongation 
Modulus/300% 
193.7.degree. C./100% 
Solubility in 
(dtex) 
(cN/dtex) 
(%) (cN/dtex) 
(seconds) 
DMF at 20.degree. C. 
__________________________________________________________________________ 
According to the invention 
(100 mVal/kg of incorporated 
309 0.65 606 187 96 insoluble 
crosslinker) 
a) 
Comparison without cross- 
linker 304 0.52 530 159 30 soluble 
b) 
Comparison with 100 mVal/kg 
of bis-crosslinker (additive) 
294 0.52 540 159 14 soluble 
c) soluble, 
Comparison with 200 mVal/kg dissolving 
of bis-crosslinker (additive) 
317 0.47 537 144 12.8 somewhat 
slowly 
__________________________________________________________________________ 
Whereas the filaments according to the invention containing 100 mVal/kg of 
incorporated crosslinker groups are highly crosslinked (insoluble) and 
show a considerable improvement in their hot break time, the additively 
introduced "bis-crosslinker" does not have a crosslinking effect so that 
the hot break times show no improvement. Tempering times of 1 hour at 
150.degree. C. are required for initiating a certain crosslinking effect 
in the case of (b) and (c), although this adversely affects the other 
properties and, in practice, is too slow for a continuous crosslinking 
reaction. 
If the solutions are dry spun (solution according to the invention) for 
comparison with the crosslinker-free solution according to comparison 
Example (a), the elastomer filaments obtained also differ considerably in 
their thermal stability. The hot break time of the uncrosslinked filaments 
is increased from 31 seconds (at 193.7.degree. C./100% elongation) to 96.5 
seconds in the case of the filament crosslinked in accordance with the 
invention, in addition to which the stability of the filament tension in 
hot water is improved. 
EXAMPLE 7 
(a) NCO-Preadduct 
500 parts of an adipic acid/1,6-hexane diol/2,2-dimethyl-1,3-propane diol 
polyester (molar ratio of the glycols 65/35) having a molecular weight of 
1950, 27.82 parts of the monoadduct diol (VII), 10.43 parts of 
bis-(.beta.-hydroxypropyl)-methylamine, 157.5 parts of diphenyl 
methane-4,4'-diisocyanate and 174 parts of dimethyl formamide are reacted 
for 95 minutes at 40.degree. C. to form an NCO-prepolymer (NCO-content 
2.82% in the solid substance). 
(b) Chain extension with hydrazine hydrate 
5 parts of the NCO-preadduct (a) are added with intensive stirring at 2.89 
parts of hydrazine hydrate in 537 parts of dimethyl formamide. A clear 
highly viscous elastomer solution is formed (378 poises/22%). 
The solution is cast into films and dried (for 45 minutes at 70.degree. 
C.+45 minutes at 100.degree. C.). The highly elastic films formed (tensile 
strength 0.64 cN/dtex; elongation at break 586%) are still soluble in 
dimethyl formamide. If the films are heated for 30 minutes at 130.degree. 
C., they crosslink and become insoluble in dimethyl formamide (20 minutes 
at 95.degree. C.). 
After brief drying in a hot air duct at about 150.degree. C., elastomer 
filaments wet spun in the usual way show an excellent hot break time of 
100 seconds at 193.7.degree. C./100% elongation by virtue of their 
crosslinking. 
(c) Reaction with .beta.-semicarbazidopropionic acid hydrazide 
9.30 parts of H.sub.2 N.NH.CO.NH.CH.sub.2 CH.sub.2.CO.NH.NH.sub.2 are 
dissolved in 18 parts of hot water, diluted with 542 parts of dimethyl 
formamide are reacted over a period of 5 minutes to form the elastomer 
solution (420 poises) by the introduction of 210 parts of the 
NCO-preadduct solution (a). 
Portions of the solution are cast into films and dried (for 70 minutes at 
100.degree. C.) to form highly elastic films (tensile strength 0.60 
cN/dtex; elongation 590%). The films are still uncrosslinked (soluble in 
dimethyl formamide at room temperature). If the films are heated for 30 
minutes to 130.degree. C., they are crosslinked and become insoluble in 
dimethyl formamide (test temperature 95.degree. C./20 minutes). 
Portions of the solution are wet spun into filaments (coagulation in 
mixtures of water and DMF (80/20) at 80.degree. C.). For complete solvent 
extraction, the filaments are aftertreated for 1 hour in water at 
90.degree. C. and dried in air. The filaments are still readily soluble in 
dimethyl formamide. The hot break time of these filaments, which is 
important for their thermal forming is only 1 second at 193.7.degree. 
C./100% elongation and is therefore inadequate. If the elastomer filaments 
are thermally aftertreated, for example for 1 hour at 130.degree. C. or by 
passage in the form of 10 loops over a heating godet heated to 175.degree. 
C. at a speed of 100 meters per minute, the hot break time undergoes a 
considerable increase to 17.5 seconds. 
The filaments show good elastic properties: tensile strength 0.72 cN/dtex 
at 542 % elongation; modulus at 300 % elongation: 0.29 cN/dtex; hot water 
elongation (HWE): 20/89/26 %; reduction in hot water (RTHW): 0.68 
mN/dtex/0.24 mN/dtex/36 %. 
EXAMPLE 8 
200 parts of an adipic acid/1,6-hexane diol/2,2-dimethyl-1,3-propane diol 
(65/35) polyester (molecular weight 1900), 4.09 parts of 
N,N-bis-(.beta.-hydroxypropyl)-methylamine, 10.90 parts of the monoadduct 
diol VIII, 58.7 parts of diphenyl methane-4,4'-diisocyanate and 68.5 parts 
of dimethyl formamide are reacted for 95 minutes at 40.degree. C. to form 
a prepolymer having an NCO-content of 1.80. 
A suspension of 1.24 parts of ethylene diamine, 306 parts of dimethyl 
formamide and 2 parts of dry ice is reacted with 100 parts of the above 
NCO-prepolymer solution to form an elastomer solution. 
The solution is cast and dried to form films which, after 30 minutes at 
130.degree. C., are insoluble in dimethyl formamide both at room 
temperature and at 95.degree. C. 
EXAMPLE 9 
300 parts of a polytetramethylene ether diol (molecular weight 2000), 6.15 
parts of N,N-bis-(.beta.-hydroxypropyl)methylamine, 88.41 parts of 
diphenyl methane-4,4'-diisocyanate and 16.39 parts of the monoadduct diol 
VII (approxiately 100 mVal of NCO-donor per kg of elastomer solids) are 
reacted with 103 parts of dimethyl formamide for 50 minutes at 40.degree. 
C. and then for 90 minutes at room temperature to form an NCO-prepolymer 
(NCO-content 2.36 % in the solid substance). 
3 Parts of dry ice and then 107.5 parts of the above NCO-prepolymer 
solution are added to 1.45 parts of ethylene dimanine in 270 parts of 
dimethyl formamide. A homogeneous solution having a viscosity of 234 
poises is formed. 
Portions of the solution are cast and dried (for 70 minutes at 100.degree. 
C.) to form films. Films heated for 30 minutes at 130.degree. C. remain 
undissolved in cold dimethyl formamide. Maximum crosslinking is obtained 
after 60 minutes at 130.degree. C. (or after 30 minutes at 150.degree. 
C.), the film remaining stable, i.e. undissolved and structurally intact, 
in dimethyl formamide at 95.degree. C., even after 3 hours. The tensile 
strength of the films is 0.68 cN/dtex, their elongation is 684% and their 
modulus at 300% is 0.115 cN/dtex. 
Another portion of the solution is spun into a bath of water and DMF 
(80/20) heated to 80.degree. C., run off at 10 meters per minute and 
subsequently freed from the solvent in hot water (90.degree. C.). The 
filaments are still soluble in dimethyl formamide. Their tensile strength 
is 0.64 cN/dtex for 644% elongation and their modulus at 300% elongation 
is 0.15 cN/dtex. 
When tested for their thermal behaviour at 193.7.degree. C./100% elongation 
(measurement of the hot break time/HBT), the filaments break after 10.2 
seconds. Although this is better than in the comparison test without the 
crosslinker diol incorporated (2 seconds), it is still not entirely 
satisfactory. However, if the filaments are afterheated for 1 hour at 
130.degree. C. or if they are passed over heating godets having a surface 
temperature of 180.degree. C., the filaments become insoluble in DMF and 
the hot break time increases considerably to 36.3 seconds at 193.7.degree. 
C. This is sufficient for thermal forming. 
When the filaments are tested (without thermal aftertreatment) for their 
heat distortion temperature (HDT), a very high HDT-value of 193.5.degree. 
C. is observed. The filaments are crosslinked during the relatively slow 
measurement which explains why they reached this high value. Similar 
crosslinking occurs during the usual treatment of elastic knitted fabrics 
on a tentering frame (for example for 20 to 30 seconds at 180.degree. to 
195.degree. C.). 
Comparison Test 
A polyurethane is synthesized in the same way as before, but in the absence 
of the monoadduct diol VII (and in the absence of its equivalent quantity 
of diphenyl methane-4,4'-diisocyanate). Films of this solution are not 
crosslinkable. Wet-spun filaments show a considerably reduced hot break 
time (.ltoreq.2 seconds) and remain soluble.