Mixtures of .alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-p-and -m-diisopropylbenzenes, a process for the preparation thereof and the use thereof as stabilizers

The invention relates to mixtures of .alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-m-diisopropylbenzene and .alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-p-diisopropylbenzen e which contain at least 20% by weight and preferably from 40 to 70% by weight of the m-compound. Moreover, the invention relates to a process for the production of such mixtures. The mixtures are suitable for stabilizing polyurethanes and other synthetic polymers against discoloration and degradation when exposed to visible and/or UV light and/or atmospheric constituents such as oxygen oxides or nitrogen and waste gases from combustion. Particularly, they are suitable for stabilizing threads and foils of these products including coatings.

This invention relates to mixtures of 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-p-diisopropylbenzenes 
and 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-m-diisopropylbenzenes, 
a process for preparing such mixtures. 
The preparation of 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-p-diisopropylbenzenes 
by the reaction of .alpha.,.alpha.'-dihydroxy-p-diisopropylbenzene with 
2,4-dialkylphenols in the presence of acid catalysts has been disclosed in 
German OS No. 2,012,285, but preparation from the corresponding 
m-diisopropylbenzene derivatives and from mixtures of the m- and 
p-compounds has not previously been described. 
.alpha.,.alpha.'-DIHYDROXYDIISOPROPYLBENZENES MAY BE OBTAINED BY 
ATMOSPHERIC OXIDATION OF DIISOPROPYLBENZENES, BUT WHEN BENZENE IS 
PROPYLATED, CUMENE, M- AND P-DIISOPROPYLBENZENE AND HIGHER PROPYLATED 
BENZENES ARE OBTAINED SIMULTANEOUSLY. Although these higher propylated 
benzenes and cumene may easily be separated from diisopropylbenzene, m- 
and p-diisopropylbenzene may only be separated with great difficulty from 
each other by distillation. p-diisopropylbenzene is therefore much more 
expensive than a mixture of m- and p-diisoproplbenzene and it became 
necessary to attempt to replace p-diisopropylbenzene by mixtures of m- and 
p-diisopropylbenzene and hence to replace .alpha.,.alpha.'-bis( 
2-hydroxy-3,5-dialkylphenyl)-p-diisopropylbenzenes by mixtures of the 
corresponding p- and m-compounds. 
In German OS No. 2,012,285, various strong acids, e.g. phosphoric acid, 
sulphuric acid, hydrochloric acid and p-toluenesulphonic acid, are 
indicated as catalysts for the conversion of 
.alpha.,.alpha.'-dihydroxy-p-diisopropylbenzene to 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-p-diisopropylbenzene. 
If mixtures of .alpha.,.alpha.'-dihydroxy-m- and -p-diisopropylbenzene. If 
mixtures of .alpha.,.alpha.'-dihydroxy-m- and -p-diisopropylbenzene are 
reacted with 2,4-dialkylphenols in accordance with the said process, no 
matter which of the above-mentioned acids used as catalyst, much lower 
yields are obtained and the end products consist of mixtures which are 
practically incapable of crystallizing and therefore very difficult to 
purify. Purification would be essential in this process since the crude 
products obtained, particularly when using p-toluene-sulphonic acid which 
is the preferred catalyst according to the above-mentioned German OS, is 
deep brown in colour. The most serious disadvantage, however, is that the 
mixtures obtained by this process have a much weaker stabilizing effect on 
polyurethanes than pure p-compounds. 
It is an object of the present invention to avoid the afore-mentioned 
disadvantages. It has now surprisingly been found that this object is 
accomplished by the reaction of mixtures of .alpha.,.alpha.'-dihydroxy-m- 
and -p-diisopropylbenzene with 2,4-dialkylphenols which results in high 
yields of readily crystallizable products if gaseous hydrogen chloride is 
used as catalyst. 
The present invention therefore relates to a process for the preparation of 
readily crystallizable mixtures of 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl-m-diisopropylbenzenes 
and .alpha.,.alpha.'-bis-(2-hydroxy-2,5-dialkylphenyl)-p-diisopropylbenzen 
es by the reaction of a mixture .alpha.,.alpha.'-dihydroxy-m- and 
-p-diisopropylbenzenes with an excess of 2,4-dialkylphenols in the 
presence of hydrogen chloride which is not bound to water. 
The process according to the present invention may be carried out 
intermittently or continuously. A preferred and technically simple method 
consists of dissolving or suspending 
.alpha.,.alpha.'-dihydroxy-diisopropylbenzene in dialkyl phenol and 
introducing hydrogen chloride into this mixture. Alternatively, a solution 
of .alpha.,.alpha.'-dihydroxy-diisopropylbenzene in 2,4-dialkylphenol may 
be introduced into a saturated solution of hydrogen chloride in the same 
dialkylphenol. For a continuous process, the reactants are mixed and the 
reaction is then completed, for example in a tube reactor attached to the 
mixing apparatus. 
The reaction must be carried out with an excess of 2,4-dialkylphenol. The 
molar ratio of .alpha.,.alpha.'-dihydroxy-diisopropylbenzene to 
dialkylphenol should be at least 1:3 and preferably from 1:5 to 1:12. 
Solvents which are inert under the reaction conditions, such as methylene 
chloride, chloroform, benzene, toluene, xylene, chlorobenzene or other 
petroleum hydrocarbons, may be used, but they are not essential. 
Hydrogen chloride must be used in sufficient quantity so that it is freely 
available in the reaction mixture over and above the amount which is bound 
as hydrochloric acid by the water produced in the reaction. If this is not 
the case, the hydrochloric acid determines the course of the reaction 
which would not then lead to the desired products. The required condition 
is most easily fulfilled by saturating the reaction mixture with hydrogen 
chloride. 
The reaction temperature employed is not particularly critical and may lie 
within a range of from 0 to 100.degree. C and is preferably from 20 to 
70.degree. C. Lower temperatures reduce the reaction velocity, while 
higher temperatures promote side reactions. 
The reaction products are easily isolated, for example, by distilling 
excess dialkylphenol from the reaction mixture. The sump product obtained 
is in many cases sufficiently pure to be used directly as stabilizer. If 
further purification is desired, the product may be recrystallized from a 
suitable solvent. 
If desired, the solvent may be added right from the start, and after the 
reaction the excess acid may be washed out with water at an elevated 
temperature and the reaction mixture left to cool and the crystalline 
material collected. the mother liquor may be used again immediately if 
desired. 
Suitable starting materials for the process according to the present 
invention are, on the one hand, mixtures of .alpha.,.alpha.'-dihydroxy-m- 
and -p-diisopropylbenzenes containing at least 20%, by weight, and 
preferably from 40 to 70%, by weight, of the m-compound, and, on the other 
hand, 2,4-dialkylphenols which may be substituted by, for example, ethyl, 
n-propyl, isopropyl, n-butyl, secondary butyl, amyl, isoamyl, hexyl, 
isohexyl, isooctyl, isononyl, 4-methylcyclohexyl, 
.alpha.-methylcyclohexyl, benzyl, .alpha.-methylbenzene or 
.alpha.,.alpha.-dimethylbenzyl, but particularly by methyl, tert.-butyl, 
cyclopentyl or cylohexyl. Those 2,4-dialkylphenols which carry a methyl 
group in the p-position are preferred. 
As mentioned above, the mixtures according to the present invention and 
.alpha.,.alpha.'-(2-hydroxy-3,5-dialkylphenyl)-m-diisopropylbenzenes have 
not previously been described. Judging from the properties of the pure 
p-compounds, it was not to be expected that the mixtures would have the 
advantages mentioned above. On the contrary, the investigations mentioned 
above which were carried out on mixtures prepared according to German OS 
No. 2,012,285 indicated that the addition of m-compound would seriously 
impair the stabilizing effect and that the mixtures obtained would be of 
no practical use. 
It must therefore be regarded as very surprising that mixtures with such 
highly advantageous properties could be obtained by the process according 
to the present invention. Firstly, it must be said that it was surprising 
to find that all the catalysts mentioned in German OS No. 2,012,285, even 
hydrochloric acid, which differs less than any of the others from the 
catalyst used according to the present invention, result in practically 
equally low yields of mixtures of poor quality. It was therefore to be 
expected that .alpha.,.alpha.'-dihydroxy-p-diisopropylbenzene would result 
in an end product with improved properties also when used in the presence 
of hydrogen chloride. This was remarkably found not to be the case. The 
yield of bis-phenol and its quality differ in no way from the yield and 
quality of bisphenol obtained with the other catalysts. This means that 
hydrogen chloride takes up a special position only in connection with the 
mixtures. 
Although Belgian Pat. No. 614,663 disclosed a process of synthesizing 
.alpha.,.alpha.'-bis-(4-hydroxyphenyl)-diisopropylbenzenes from 
.alpha.,.alpha.'-dihydroxy-diisopropylbenzenes with the aid of hydrogen 
chloride, it only mentions hydrogen chloride together with other catalysts 
which may be used equally successfully. It gives no indication that the 
situation is the same when alkylating 2,4-substituted phenols as when 
alkylating phenols which are free in the para-position and still less does 
it give any indication that mixtures of .alpha.,.alpha.'-dihydroxy-m- and 
-p-diisopropylbenzene would behave in an anomalous manner. 
The mixtures according to the present invention are at least equally good 
in their stabilizing qualities as the pure p-compounds while in other 
properties they are superior. Owing to their higher solubility, they may 
be more readily incorporated in polyurethanes and will not undergo any 
further crystallization in them as is occasionally observed in the case of 
p-compounds. This solid phase separation reduces the surface gloss of 
polyurethane products, a phenomenon which is particularly noticeable in 
products, such as fibres, which have a large surface area. 
A further object of the present invention are mixtures of 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-m-diisopropylbenzene 
and .alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-p-diisopropylbenzen 
e which contain at least 20 %, by weight, and preferably from 40 to 70 %, 
by weight, of the m-compound. Mixtures of 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dimethylphenyl)-p-diisopropylbenzene 
and 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dimethylphenyl)-m-diisopropylbenzene 
are preferred. 
Mixtures of 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-p-diisopropylbenzene 
and .alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-m-diisopropylbenzen 
e are used for stabilizing polymers, in particular polyethers, such as 
polytetrahydrofuran, polypropylene oxides, polyethylene oxides with OH end 
groups and for stabilizing derivatives thereof, such as esters, urethanes 
and amides. The mixtures are also used for stabilizing polycondensation 
products (such as polyamides, polyesters or mixtures thereof or mixtures 
of the polyamides or polyesters with additives) and for stabilizing 
polymerisation products and polyaddition products, such as polymers based 
on polyisocyanates or epoxides. 
Lastly, the present invention relates, in particular, to mixtures of 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dialkylphenyl)-m- and 
-p-diisopropylbenzenes for stabilizing polyurethanes against discoloration 
and degradation when exposed to visible and/or UV light and/or atmospheric 
constituents (such as oxygen, oxides of nitrogen and waste gases from 
combustion), particularly for stabilizing threads and foils of these 
products, including coatings. 
The elastic polyurethanes which are required to be stabilized and which may 
in some cases be in the form of foams may be produced by conventional 
processes and from conventional starting materials. The polyurethanes are 
generally prepared by any of numerous well known and modifiable processes 
in which higher molecular weight polyhydroxyl compounds (e.g. polyesters 
or polyethers having a molecular weight of from 500 to 5,000 and a melting 
point preferably below 60.degree. C) are reacted with aliphatic, 
araliphatic or aromatic polyisocyanates (preferably aromatic 
diisocyanates, such as tolylene diisocyanate or 
diphenylmethane-4,4'-diisocyanate) and so-called "chain lengthening 
agents", i.e. low molecular weight compounds (molecular weight e.g. from 
18 to 400) which contain two or more groups capable of reacting with 
isocyanate groups (e.g. water, low molecular weight diols, diamines, 
dihydrazides or similar compounds, e.g. amino alcohols, amino hydrazides, 
hydroxy hydrazides, amino semicarbazides, semicarbazidohydrazides, 
semicarbazidocarbazic esters or mixtures of these chain lengthening 
agents) in one or more stages with or without solvent. 
The following are mentioned as examples of starting materials: polyesters 
of adipic acid and dihydricalcohols containing from 2 to 10 carbon atoms, 
preferably more than 5 carbon atoms, the dihydricalcohols optionally also 
being used as mixtures in order to lower the melting points of the 
polyesters: polyesters of caprolactone and dihydricalcohols, polyalkylene 
ether diols, specifically polytetramethylene ether diols, polytrimethylene 
ether diols, polypropylene glycol or copolyethers thereof. The 
diisocyanates used are preferably aromatic diisocyanates, such as 
diphenylmethane-4,4'-diisocyanate, tolylene diisocyanate, araliphatic 
diisocyanates, such as m-xylylene diisocyanate, or aliphatic 
diisocyanates, such as hexamethylene diisocyanate and 
dicyclohexylmethane-4,4'-diisocyanate. These starting materials, if 
desired together with additional dihydric alcohols, are converted into 
isocyanate prepolymers which preferably have the structures indicated in 
Belgian Pat. No. 734,194. The following are examples of suitable chain 
lengthening agents, which may, if desired, be used as mixtures or reacted 
stepwise: water and/or dihydric or trihydric alcohols, such as butane diol 
and p-xylylene glycols, trimethylolpropane, amino alcohols, such as 
ethanolamine, diamines, such as diphenylmethane-4,4'-diamine and 
3,3'-dichlorodiphenylmethane-4,4'-diamine. It is preferred, however, to 
use aliphatic diamines, such as ethylene diamine, 1,2-propylene diamine, 
isophorone diamine, metaxylylene diamine and hydrazine or dihydrazides, 
such as carbodihydrazide, oxalic acid dihydrazide, glutaric acid 
dihydrazide, pimelic acid dihydrazide and terephthalic acid dihydrazide or 
semicarbazido hydrazides, such as .beta.-semicarbazide-alanyl hydrazide. 
These chain lengthening agents may, if desired, be used as mixtures. 
The products are preferably used for stabilizing polyurethanes which, in 
addition to urethane groups, contain --NH--CO--NH-- groups formed by the 
reaction of isocyanate groups with water and/or with compounds containing 
NH.sub.2 end groups (e.g. diamines, dihydrazides, carbodihydrazide, 
semicarbazidohydrazides or hydrazine), and which have a substantially 
linear, segmented molecular structure, are soluble in highly polar 
solvents, such as dimethylformamide or dimethyl acetamide, before they are 
shaped and have characteristic segments which may be represented by the 
following general formula: 
EQU --Y.NH.CO.NH.X.NH.CO.NH -- 
this segment may be obtained by the reaction of an isocyanate prepolymer 
OCN.Y.NCO with a chain lengthening agent H.sub.2 N.X.NH.sub.2. 
The group Y of the isocyanate prepolymer may, for example have the 
following structure: 
EQU --R.NH.CO.O.D.O.CO.NHR-- 
or it may have some other, commonly occurring composition (see Belgian Pat. 
No. 734,194). 
In the above formula, R represents a divalent aliphatic, araliphatic or 
aromatic residue )of a diisocyanate), D represents the residue of a high 
molecular weight polyhydroxyl compound having a molecular weight of from 
500 to 5000 and a melting point below 60.degree. C without its hydroxyl 
end groups (e.g. the residue of a polyalkylene ether, polyester, 
polyacetal or poly-N-alkylurethane). X represents the residue of a 
divalent chain lengthening agent which contains NH.sub.2 end groups, 
without the said NH.sub.2 end groups, e.g. an aliphatic, araliphatic, 
aromatic or heterocyclic residue, a HN--CO--alkylene--CO--NH residue, an 
NH--CO--NH--(CH.sub.2).sub.2 --CO--NH residue or a bond between two 
nitrogen atoms. The synthesis of such polyurethane (urea) has been 
described in detail, for example in German Auslegeschrift No. 1,270,276 
and in Belgian Pat. No. 734,194. Polyurethane foams, for example, may be 
prepared by conventional processes and from conventional formulations with 
the addition of the stabilizers to the starting components (e.g. 
polyethers) (see for example, Kunststoff Handbuch, Volume VII, 
Polyurethane, Carl Hanser Verlag Munchen, 1966, pages 440 to 457 and 504 
to 531). 
The stabilizers may be incorporated with the polyurethanes by any methods 
suitable for the technical requirements of the process. A very simple 
method consists of adding the stabilizers, if desired as solutions, to 
solutions of the polyurethanes, for example to the polyurethane solutions 
in highly polar solvents, such as dimethylformamide or dimethylsulphoxide, 
which are the ones most preferably used for spinning, coating and 
coagulation purposes. Alternatively, the stabilizers may be worked into 
the melts or plasticized polyurethane sheets by means of suitable mixing 
devices, such as kneaders or rollers. In the case of elastomer threads, 
the stabilizers may, if desired, be applied to their surface together with 
the finish. 
Another method of incorporating the stabilizers consists of adding them to 
the starting materials used for the preparation of the polyurethanes 
before polyurethane synthesis is carried out. Bisphenol compounds, are 
soluble for example, in high molecular weight polyhydroxyl compounds (e.g. 
polyesters or polyethers). These polyesters or polyethers already 
containing stabilizers may then be used for suitable polyurethane 
syntheses, for example for the production of foams or elastomers. The 
stabilizers may also be added to diisocyanates or to isocyanate 
prepolymers obtained from higher molecular weight polyhydroxyl compounds 
and diisocyanates (used in excess molar quantities) before the 
polyurethane product is produced, for example by spinning it into aqueous 
diamine solution. Discoloration of the polyurethanes may already be 
prevented at the stage of their synthesis by adding the stabilizers when 
the isocyanate prepolymers are being reacted with chain lengthening 
agents, such as diamines, hydrazine, hydrazides, or similar chain 
lengthening agents, in highly polar solvents, such as dimethylformamide or 
dimethylacetamide. The quantity of stabilizers added ranges from 0.01 to 
10%, by weight, and is preferably from 0.1 to 5% by and most preferably 
from 0.3 to 3%, by weight. 
The protection against light is found to be further increased by addition 
of the stabilizers according to the present invention to polyurethanes 
which contain from 0.02 to 1 mol, preferably from 0.05 to 0.3 mol of 
reactants with tertiary, aliphatically substituted amino groups, based on 
1 kilogram of elastomer substance. Suitable reactants of this type 
include, for example, glycols, diamines, dihydrazides, polyesters or 
polyethers with tertiary amino groups, e.g. 
N,N-bis-(.beta.-hydroxypropyl)-methylamine, 
N,N'-bis-(.beta.-hydroxyethyl)-piperazine, 
N,N'-dimethyl-N,N'-bis-(.gamma.-aminopropyl)-ethylenediamine, 
N,N'-bis-(.gamma.-aminopropyl)-piperazine or polyethers which contain 
tertiary amino groups or polyesters which contain tertiary amino groups 
and which are prepared from dihydricalcohols containing tertiary amino 
groups. 
The following experiments illustrate the connections explained above, using 
2,4-dimethylphenyl as non-limiting example. "Parts" are parts on weight 
basis.

The following Examples are to further illustrate the invention without 
limiting it. 
Comparison Example 1 
This Example shows that p-toluenesulphonic acid used as catalyst provides 
high yields of bisphenol when used with 
.alpha.,.alpha.'-dihydroxy-p-diisopropylbenzene, but poor yields when used 
with an isomeric mixture. 
a. A solution of 1164 g (6 mol) of a 
.alpha.,.alpha.'-dihydroxy-p-diisopropylbenzene in 5490 g (45 mol) of 
2,4-dimethylphenol is added dropwise with stirring to a solution of 1830 g 
(15 mol) of 2,4-dimethylphenol over a period of from 9 to 10 hours at 
150.degree. C under an atmosphere of nitrogen. From 200 to 210 g of water 
evaporate off during this time. The reaction mixture is then stirred for a 
further 15 minutes, the catalyst is neutralised with 6.5 g of sodium 
carbonate, and 2,4-dimethylphenyl is removed by distillation at reduced 
pressure until the sump temperature reaches 140.degree. C at 12 Torr. A 
light coloured, crystalline residue is obtained in a quantity of 2230 g = 
93% of the theoretical yield. 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dimethylphenyl)-p-diisopropylbenzene 
is obtained in 80% yield (melting point 179.degree. C) when 100 g of the 
residue are recrystallised from 150 ml of tetrachloroethane. 
b. If the same procedure is adopted with a mixture of about 60% of 
.alpha.,.alpha.'-dihydroxy-m-diisopropylbenzene and about 40% of 
-p-diisopropylbenzene, the residue obtained after removal of excess 
2,4-dimethylphenol by distillation consists of 1410 g = 59% of the 
theoretical yield of a dark brown resin which does not crystallise and 
cannot by crystallised even by treatment with various solvents 
(tetrachloroethane, toluene, xylene, mineral spirits). 
Comparison Example 2 
Poor yields are also obtained with phosphoric acid and hydrochloric acids 
when an isomeric mixture of .alpha.,.alpha.'-dihydroxy-diisopropylbenzene 
is used. 
a. The same procedure is employed as in Comparison Example 1, but using 25 
g of concentrated phosphoric acid instead of p-toluenesulphonic acid and 
neutralizing with the corresponding quantity of base after the reaction. 
Only 950 g = 37% of the theoretical yield of a light coloured, 
non-crystallizable resin are obtained. 
b. The reaction mixture and procedure differ in the following respects from 
those employed in comparison Example 1: 400 g of 20% hydrochloric acid are 
used instead of p-toluene sulphonic acid. The condensation temperature is 
maintained at from 90.degree. to 95.degree. C on account of the boiling 
point of hydrochloric acid, and no water is distilled off. After the 
reaction, hydrochloric acid and dimethylphenol are distilled off without 
previous neutralisation. Yield: 1395 g = 58% of the theoretical yield of a 
light brown, non-crystallizable resin. 
EXAMPLE 1 
This Example demonstrates that when hydrogen chloride is used as catalyst 
with an isomeric mixture of .alpha.,.alpha.'-dihydroxy-diisopropylbenzene, 
it differs from the catalysts previously used in that it brings about an 
excellent improvement in the yield and quality of the reaction product, 
but when used with .alpha.,.alpha.'-dihydroxy-p-diisopropylbenzene it does 
not differ from other catalysts. 
a. A solution of 194 g (1 mol) of a mixture of about 60% of 
.alpha.,.alpha.'-dihydroxy-m-diisopropylbenzene and about 40% of 
.alpha.,.alpha.'-dihydroxy-p-diisopropylbenzene in 611 g (5 mol) of 
2,4-dimethylphenol is added dropwise with stirring in the course of 1 hour 
to another 611 g of 2,4-dimethylphenol which has been saturated with 
hydrogen chloride at 50.degree. C, and at the same time sufficient 
hydrogen chloride is passed through the reaction mixture to keep it 
saturated. The temperature during this procedure is maintained at from 
50.degree. to 60.degree. C. After a further 2 hours under these 
conditions, hydrogen chloride, hydrochloric acid and excess 2,4-dimethyl 
phenol are distilled off in a water-jet vacuum until the sump temperature 
is from 180.degree. to 190.degree. C. A yellow oil which crystallises on 
cooling is obtained in a yield of 384 g = 95.5% of the theoretical yield. 
322 g = 80% of the theoretical yield of colourless crystals (melting point 
from 135 to 179.degree. C) are left after recrystallisation from 1.6 l of 
mineral spirits. 
(b) If the same procedure is employed as in Example 1(a), but using 
.alpha.,.alpha.'-dihydroxy-p-diisopropylbenzene instead of the isomeric 
mixture, the yield of crude product is 372 g = 93% of the theoretical 
yield, and the yield after recrystallisation is 320 g = 80% of the 
theoretical yield. 
The yields obtained in Example 1(b) are similar to those obtained in 
Example 1(a), i.e. hydrogen chloride and p-toluenesulphonic acid no not 
differ in their end effect in this case. 
The pure m-compound, 
.alpha.,.alpha.'-bis-'2-hydroxy-3,5-dimethylphenyl)-m-diisopropylbenzene, 
has a melting point of from 190.degree. to 191.degree. C. 
According to calculations based on gas chromatographic analysis, the ratio 
of isomers of the product prepared according to Example 1 corresponds to 
that of the biscarbinol put into the process. 
EXAMPLE 2 
A solution of 97 g (0.5 mol) of m/p-biscarbinol (ratio of isomers 3:2) in 
382 g (2 mol) of o-cyclohexyl-p-cresol is added dropwise with stirring in 
the course of 6 hours to a mixture of 482 g (2 mol) of 
o-cyclohexyl-p-cresol and 350 ml of toluene which has been saturated with 
hydrogen chloride at room temperature, and at the same time the 
introduction of HCl is continued and the reaction temperature is 
maintained at from 20.degree. to 22.degree. C. The reaction mixture is 
left to stand overnight and subsequently heated to 50.degree. to 
60.degree. C and hydrogen chloride, hydrochloric acid and excess 
cylcohexyl cresol are distilled off under vacuum. 240 g = 89% of the 
theoretical yield of a light colored residue are left behind. On addition 
of methanol, this residue crystallises to yield 170 g of product (melting 
point: from 153.degree. to 172.degree. C). The phenolic OH content is 6.2% 
(calculated 6.3%). 
EXAMPLE 3 
97 g (0.5 mol) of m/p-biscarbinol are reacted with 656 g (4 mol) of 
2-tert.-butyl-p-cresol as described in Example 2, but in the presence of 
only 100 ml of toluene. After removal of the volatile constituents by 
distillation, particularly of excess butyl cresol, 239 g = 98% of the 
theoretical yield of a light coloured residue are obtained. This residue 
crystallises with mineral spirits to yield 195 g of product (melting point 
from 130.degree. to 144.degree. C), phenolic OH content 7.1% (calculated 
7.0%). The ratio of isomers, which is found to be 6.5:3.5 lies within the 
limits of error of measurement of the biscarbinol used. 
EXAMPLE 4 
1200 parts of a copolyester of adipic acid, hexane-1,6-diol and 
2,2-dimethylpropane-1,3-diol (molar ratio of diols 65:35) (molecular 
weight of copolyester 1950), 23.55 parts of 
N-methyl-bis-(.beta.-hydroxypropyl)-amine, 342.65 parts of 
diphenylmethane4,4'-diisocyanate and 393 parts of anhydrous 
dimethylformamide are heated to from 45.degree. to 50.degree. C for 80 
minutes to form the isocyanate prepolymer which has an isocyanate content 
of 3.06% (based on the solids content). (The polymer contains about 100 
mVal of tertiary amino groups per kg). 
70 parts of dry ice (CO.sub.2) are added to 28.3 parts of 99.5% ethylene 
diamine in 3392 parts of dimethylformamide to form a fine carbamate 
suspension, and 1590 parts of the above-mentioned isocyanate prepolymer 
solution are then introduced within 4 minutes. The solution is pigmented 
with 4% of TiO.sub.2 (rutile) (viscosity: 1230 poises/20.degree. C). The 
solution is subsequently diluted with dimethylformamide to a solid 
concentration of 22.8% / 540 poises. The stabilizers are added to portions 
of the solutions, in each case dissolved in a small quantity of 
dimethylformamide. 
The solutions are spun through a 16 aperture die (diameter 0.2 mm) by the 
dry spinning process, drawn off the spinning shaft at the rate of 100 
m/min and wound on spools at the rate of 130 m/min. The filaments were 
dressed with talcum. 
The measurements indicated in Table 1 were carried out on filaments which 
had been tempered for one hour at 130.degree. C. 
The effect of the stabilizers on the thermal properties of the filaments is 
shown in Table 2. 
Dry spun filaments were in part subjected to a thermostability test and the 
reduction in molecular weight was measured as the .eta..sub.i -value 
(.eta..sub.i = 1n.eta.R/C; .eta.R = relative viscosity; C = concentration 
in g/100 ml of hexamethylphosphoramide, measuring temperature = 25.degree. 
C) (see Table 1). The filaments containing additives remained colourless 
when exposed to heat treatment at 180.degree. C. (The values for tensile 
strength are given in g/dtex and for elongation at break in % in the 
following Tables). 
Table 1 
__________________________________________________________________________ 
Heat stabilization by additives (filaments after dry 
spinning experiment) 
__________________________________________________________________________ 
values original after after 
.eta. 1 30 sec/180.degree. C 
180 sec/180.degree. C 
__________________________________________________________________________ 
with additive 1.10 1.09 0.99 
(-0.9%) (.DELTA. -10%) 
+ 2% Stabilizer 1a 1.10 1.10 1.052 
.DELTA. .+-. 0%) 
(.DELTA. -4.4%) 
+ 1% of stabilizer 1a 
1.10 1.11 1.048 
+ 1% of UV stabilizer B (.DELTA. +0.9%) 
(.DELTA. -4.8%) 
(Tinuvin 327 Ciba/Geigy) 
+ 1.5% 
of stabilizer 1a 
1.10 1.09 1.050 
+ 1% of UV stabilizer B (-0.9%) (.DELTA. -4.5% 
(Tinuvin 327 Ciba/Geigy) 
+ 1% stabilizer 1a 1.10 1.11 1.052 
+ 1% of UV stabilizer C (-4.4%) 
__________________________________________________________________________ 
Table 2 
__________________________________________________________________________ 
Effect of stabilizers on thermal properties of dry spun elastomer 
filaments 
__________________________________________________________________________ 
Ultimate tensile 
Elongation 
Heat distortion.sup.(a) 
Heat tearing time.sup.(b) 
strength at break 
Temperature (.degree. C) 
(seconds) 
__________________________________________________________________________ 
Without additive 
0.61 490 183.5 60.6 
+ 1% of stabilizer 1a 
0.62 535 188.5 61.0 
+ 1% of UV stabilizer B 
+ 1.5% of stabilizer 1a 
0.63 527 185.5 67.5 
+ 0.5% of UV stabilizer B 
+ 2% of UV stabilizer B 
0.62 519 183.5 52.5 
__________________________________________________________________________ 
.sup.(a) The temperature at which a filament to which a weight of 1.8 
mg/dtex has been suspended exceeds an elongation of 0.8% per .degree. C 
when heated at the rate of 2.1.degree. per minute. 
.sup.(b) Measurement of the time (seconds) at which a filament which has 
been stretched by 100% breaks off on a metal support 2.5 centimeters in 
width which is at a temperature of 193.degree. C. 
EXAMPLE 5 
2000 parts of a copolyester of adipic acid, hexane-1,6-diol and 
2,2-dimethylpropane-1,3-diol (molar ratio of diols 65:35) which has an 
average molecular weight of 2000 are mixed with 28.10 parts of 
N-methyl-bis-.beta.-hydroxypropylamine (66 mVal of tert. amine/kg of solid 
substance) and a solution of 547.8 parts of 
diphenylmethane-4,4'-diisocyanate in 645 parts of dimethylformamide at 
40.degree. C and the mixture is reacted for 90 minutes at from 40.degree. 
to 60.degree. C to produce an isocyanate prepolymer (2.99% of isocyanate, 
based on the solid content). 
3000 parts of the isocyanate prepolymer solution are stirred into a 
suspension of 110 parts of rutile and 56.40 parts of ethylene diamine in 
8460 parts of dimethylformamide and 130 parts of solid carbon dioxide in 
the course of 5 minutes. After the addition of 7.2 parts of 
hexane-1,6-diisocyanate, the solution has a viscosity of 700 
poises/20.degree. C. It is then subdivided into three portions as follows: 
a. without the addition of stabilizer 
b. with 1% of stabilizer 1a 
c. with 2% of stabilizer 1a 
The solutions are spun by the dry spinning process. The draw-off rate is 
250 m/min. Filaments with a titre of about 140 dtex are left to stand for 
24 hours and then heat treated on rollers (temperature from 180.degree. to 
200.degree. C) at a permitted shrinkage in German Offenlegungsschrift No. 
1,660,294. The results of measurements carried out on filaments with and 
without the addition of stabilizer after exposure in a Xeno test for up to 
about 340 hours are shown in Table 3. 
Table 3 
__________________________________________________________________________ 
Effect of stabilizers on the resistance to ultraviolet light exposure in 
the Xeno test of dry spun, 
thermally after-treated elastomer filaments (Filament titre about 160 
dtex) 
__________________________________________________________________________ 
Discoloration, ultimate tensile strength and elongation at break after 
Xeno test exposure for x hours 
__________________________________________________________________________ 
without 
exposure 
after 70 hours 
after 143 hours 
after 245 hours 
after 340 
__________________________________________________________________________ 
hours 
without stabilizer 
0.95.sub./525 
0.59.sub./470 
0.30.sub./375 
0.16.sub./270 
0.14.sub./220 
almost colourless 
yellowish yellow deep yellow 
+ 1% of stabilizer 1a 
1.00.sub./515 
0.96.sub./480 
0.60.sub./435 
0.37.sub./375 
0.27.sub./340 
colourless colourless 
colourless 
almost colour- 
less to 
yellowish 
+ 2% of stabilizer 1a 
1.04.sub./525 
0.98.sub./490 
0.93.sub./490 
0.62.sub./450 
0.37.sub./350 
colourless colourless 
colourless 
almost colour- 
less 
__________________________________________________________________________ 
EXAMPLE 6 
An elastomer spinning solution was prepared by the process according to 
Example 5 from 2000 parts of polyester (molecular weight 2000), 38.26 
parts of N-methyl-bis-(.beta.-hydroxypropyl)-amine (about 100 mVal of 
tert.amine/kg of solid substance) and 565.10 parts of 
diphenylmethane-4,4'-diisocyanate in 650 parts of dimethylformamide. These 
components were reacted to from an isocyanate prepolymer (3.00% 
isocyanate) and 3000 parts of this prepolymer were chain lengthened with 
56.58 parts of ethylene diamine, 8461 parts of dimethylformamide, 140 
parts of solid carbon dioxide and 7.76 parts of hexane-1,6-diisocyanate. 
The resulting spinning solution was mixed with 13 parts of acetic acid 
anhydride to remove any residual amino end groups and with 4%, by weight, 
of TiO.sub.2 (in the solid substance). 
The solution was divided up into portions to which the following 
stabilizers were added, and then spun by the conventional dry spinning 
process: 
a. without the addition of stabilizer 
b. with 2%, by weight, of stabilizer according to 1a 
c. with 1%, by weight, of stabilizer according to 1a and 1%, by weight, of 
UV stabilizer A 
d. with 1%, by weight, of stabilizer according to 1a and 1%, by weight, of 
UV stabilizer B 
e. with 2%, by weight, 
.alpha.,.alpha.'-bis-(2-hydroxy-3,5-dimethylphenyl)-m-diisopropylbenzene,m 
.p.:from 190.degree.-191.degree. C. 
When elastomer filaments containing additive (e) (i.e. pure m-compound of 
the stabilizer) are warped on sectional beams, a large amount of additive 
which has been deposited on the surface of the filaments is rubbed off. UV 
stabilizer A = "Tinuvin 320"/Ciba-Geigy 
2-(2'-hydroxy-3',5'-di-tert.-butyl-phenyl)-benzotriazole! UV stabilizer B 
= "Tinuvin 327"/Ciba-Geigy 
2-(2'-hydroxy-3',5'-di-tert.-butyl-phenyl)-5-chlorobenzotriazole! 
UV stabilizer C = 
##STR1## 
When 2% of stabilizers according to Example 2 or Example 3 is used, it is 
found that while the stabilizing effect is substantially the same as that 
obtained with the stabilizer according to Example 1(a), the stabilizers 
are even more readily soluble and they are very compatible with the 
polymers. 
Table 4 
______________________________________ 
Effect of stabilizers and of their mixtures with UV 
stabilizers on the resistance of dry spun elastomer 
filaments to UV exposure in the Xeno test 
(Filament titre about 160 dtex) 
Discoloration, ultimate tensile strength and elongation at break 
after Xeno test exposure for x hours 
without 
exposure 
after 305 hours 
______________________________________ 
(a) without stabilizer 
0.85/515 0.25/364 yellow 
(b) + 2% of stabilizer 1a 
0.81/515 0.48/460 colourless 
(c) + 1% stabilizer 1a 
0.90/552 0.66/501 colourless 
1% of UV stabilizer A 
(d) + 1% of stabilizer 1a 
0.80/515 0.62/485 colourless 
1% of UV stabilizer B 
______________________________________ 
EXAMPLE 7 
600 parts of a copolyester of adipic acid, hexane-1,6-diol and 
2,2-dimethylpropane-1,3-diol (molar ratio of diols 65:35) (molecular 
weight of copolyester 1615), 12 parts of 
N-methyl-bis-(.beta.-hydroxypropyl)-amine, 169 parts of 
diphenylmethane-4,4-diisocyanate and 195 parts of dimethylformamide are 
heated with 2.38% of isocyanate (based on solid substances) to a 
temperature of from 50.degree. to 54.degree. C for 80 minutes to form an 
isocyanate preopolymer. 
322.5 parts of the isocyanate prepolymer solution mentioned above and 4 
parts, by weight, of TiO.sub.2 (based on solid substance) are stirred into 
a solution of 11.8 parts of .beta.-semicarbazido-propionic acid hydrazide 
in 23.6 parts, by weight, of water which has been heated to 50.degree. C 
and diluted with 670 parts of dimethylformamide. A highly viscous 
elastomer solution (655 poises/20.degree. C) is thereby obtained. 
The solution was divided into portions to which the following stabilizers 
were added: 
a. no stabilizer 
b. 2% of stabilizer 1a 
c. 1% of stabilizer 1a 
d. 1% of stabilizer 1a + 1% of UV stabilizer B 
e. 2% of stabilizer II of German O No. 2,012,285, and the portions were 
cast to form films which were exposed in a Fadeometer. 
While film (a) is yellow after only 22 hours, film (b) remains colourless 
for up to 66 Fadeometer hours. Film (c) begins to undergo discoloration 
after 66 Fadeometer hours, film (d) remains colourless like film (b) while 
film (e) begins to show slight discoloration after 30 Fadeometer hours and 
becomes increasingly yellow on further exposure up to 66 hours (comparison 
experiment). 
When the samples are treated in boiling water for one hour on subjected to 
solvent extraction in boiling carbon tetrachloride for 15 minutes, the 
stabilizing effect is clearly better preserved in film (b). Substantial 
discoloration begins only after 66 Fadeometer hours while in comparison 
film (e) severe discoloration is seen after only 30 hours (in the case of 
solvent extraction). During the boiling treatment, the stabilizer in 
portion (e) migrates to the surface where it forms a deposit on the films. 
This is not observed in portions containing stabilizer (b) according to 
the present invention. 
EXAMPLE 8 
800 parts of polytetramethylene ether diol (molecular weight 1045) are 
reacted with 16.45 parts of N-methylbis-(.beta.-hydroxypropyl)-amine and 
285.9 parts of diphenylmethane-4,4-diisocyanate and 278 parts of 
dimethylformamide at a temperature of from 35.degree. to 50.degree. C for 
40 minutes to form an isocyanate prepolymer with an NCO content of 2.09% 
(based on the solid content). 
1. Chain lengthening with ethylene diamine: 
5.24 parts of ethylene diamine and 895 parts of dimethyl formamide are 
converted into a carbamate suspension with 10 parts of solid carbon 
dioxide, and 440 parts of the prepolymer solution mentioned above are 
added within 3 minutes. The substance is then pigmented with 4% of 
TiO.sub.2. 
2. Chain lengthening with hydrazine hydrate: 
4.37 parts of hydrazine hydrate are dissolved in 895 g of dimethylformamide 
and converted into the carbonate by the addition of 10 g of solid carbon 
dioxide. 425 parts of the above-mentioned isocyanate prepolymer solution 
are introduced within 3 minutes. The solution is then pigmented with 4%, 
by weight, of TiO.sub.2 (rutile). 
Portions of both solutions were treated with the following stabilizers: 
a. no stabilizer 
b. 1%, by weight, of stabilizer 1a according to the present invention, + 
1%, by weight, of light absorbing agent D 
c. 1%, by weight, of stabilizer 1a + 1%, by weight, of light absorbing 
agent D + 2%, by weight, of light absorbing agent according to Example 4 
of German Patent Application P 25 20 814.4. 
The solutions are then cast to form films and exposed in a Fadeometer. 
D = light absorbing agent of the formula: 
##STR2## 
Whereas the unstabilized films were discoloured yellow after only 8 hours 
(film 1a) or 15 hours (film 2a) and had no mechanical strength (less than 
0.08 g/dtex) after from 22 to 30 hours exposure in the Fadeometer and 
showed severe crazing on the surface, the exposed films were still 
colourless after 66 Fadeometer hours (the test was stopped at this point), 
they showed no signs of degradation or loss of elasticity and no crazing 
effect on the surface. Such stabilization of polyether ureas, which are 
very sensitive substances, must be regarded as excellent. 
EXAMPLE 9 
600 parts of a hexane-1,6-diol polycarbonate (molecular weight 1925) having 
OH number 58.25 are heated to 97.degree. C together with 138.5 parts of 
1-isocyanatomethyl-3,5,5-trimethylcyclohexane and 185.5 parts of the 
aromatic hydrocarbon mixture "Solvesso 100" (Manufactured by Shell) for 
about 220 minutes. A prepolymer solution having an isocyanate content of 
3.58% (in the solid substance) is obtained. 
4.2 parts of diaminocyclohexane (17.3% of cisisomer and 82.7% of 
trans-isomer) in 233 parts of Solvesso/ethylene glycol (1:1) are 
introduced into a reaction vessel and 107.5 parts of the prepolymer 
solution are added with stirring. A homogeneous solution which is stable 
in storage and has a viscosity of 266 poises/20.degree. C is obtained. 
The films are cut up into threads and exposed in a Fadeometer. 
The alihatic polyurethane (used for dressings or coating compounds) remains 
colourless even after prolonged exposure to light, in contrast to aromatic 
polyurethanes, but it suffers a loss in tensile strength. Degradation is 
considerably slowed down by the addition of stabilizer according to the 
present invention. 
Table 5 
______________________________________ 
154 hours exposure 
time of cut threads 
Original 
in the Fadeometer 
______________________________________ 
RF (g/dtex) 
without 0.69 0.29 
stabil- 
discoloration 
izer colourless 
colourless 
RF (g/dtex) 
+ 2% of 0.69 0.63 
stabil- 
discoloration 
izer 1a colourless 
colourless 
______________________________________ 
RF* = ultimate tensile strength. 
EXAMPLE 10 
The following are incorporated in portions of the elastomer solution which 
has been pigmented with TiO.sub.2 according to Example 4: 
a. no stabilizer 
b. 2% of stabiliser 4 according to German Patent application No. P25 20 
814.4 
c. 2% of stabilizer 4 according to German Patent appliction P25 20 814.4 + 
1% of stabilizer 1a (according to the present invention) 
d. 2% of stabilizer 4 according to German Patent application P 25 80 814.4 
+ 2% of stabilizer 1a (according to the present invention). 
The portions of solution are then cast to form films and the films are cut 
up into rectangular threads (about 280 dtex) which are all exposed to a 
Fadeometer at the same time. 
Table 6 shows the improvement in colour stability and preservation of the 
mechanical-elastic values (ultimate tensile strength and elongation at 
break). It may be seen that the addition of stabilizers according to the 
present invention may produce a marked increase in the effect of the 
stabilizers according to German Patent Application P 25 20 814.4. 
Table 6 
__________________________________________________________________________ 
Ultimate tensile strength, elongation at break and discoloration of cut 
polyester 
urethane urea elastomer threads after exposure in the Fadeometer 
without 
exposure 
after 8 hours 
after 22 hours 
after 44 hours 
after 66 hours 
__________________________________________________________________________ 
(a) 
without stabilizer 
0.59/628 
0.45/590 
0.11/365 
0.07/140 
-- 
yellow deep yellow 
deep yellow 
(b) 
+ 2% of stabilizer 4 
0.58/617 
0.56/605 
0.45/592 
0.29/525 
0.09/350 
according to P 25 20 
814.4 colourless 
almost col- 
yellowish to 
yellow 
ourless 
yellow 
(c) 
+ 2% of stabilizer 4 
0.56/622 
0.56/625 
0.54/625 
0.51/625 
0.39/574 
according to P 25 20 
814.4 colourless 
colourless 
colourless 
almost colour- 
+ 1% of stabilizer 1a less 
(according to the 
present invention) 
(d) 
+ 2% of stabilizer 4 
0.65/652 
0.62/647 
0.52/645 
0.54/635 
0.40/590 
according to P 25 20 
colourless 
colourless 
colourless 
colourless 
814.4 
+ 2% of stabilizer 1a 
(according to the 
present invention) 
__________________________________________________________________________