The invention relates to novel high molecular weight polyester-ester urethanes containing blocks of ester units of a high melting polyester and of blocks of ester units of a low melting polyester which are linked together through ester groups and/or urethane groups. The melting point of the polyester-ester urethanes is at least 150.degree. C. and when the blocks of ester units of the low melting polyester form part of less than 50% by weight of the total number of ester units the upper limit of the glass transition range Tg.sub.(e) thereof does not exceed +20.degree. C. and when said blocks of ester units of the low melting polyester form part of more than 50% by weight of the total number of ester units, the upper limit of the glass transition range Tg.sub.(e) is not higher than -5.degree. C. The polyester-ester urethanes are prepared by reacting a high melting polyester and a low melting polyester in the molten phase, after which the resulting polyester-ester is reacted with a low molecular weight polyisocyanate. When the number of end groups of the high melting polyester and the low-melting polyester together amount to more than 700 meq per kg, the transesterification catalyst present in one or in both polyesters or polyester amides is entirely or partly deactivated before and/or during the preparation of the polyester-ester.

The invention relates to a polyester-ester urethane built up of 
polyester-ester units which are linked together by low molecular weight 
structural units of the formula 
##STR1## 
wherein R.sub.1 represents a polyfunctional organic group having not more 
than 30 carbon atoms, and p is an integer of 2 or 3, which polyester-ester 
units are built up of blocks comprising a multiple of ester units of the 
formula 
##STR2## 
and blocks comprising a multiple of ester units which may form a 
bifunctional polyester or polyester amide having a melting point not 
higher than 100.degree. C., which two types of polyester units are linked 
together by ester bonds, with the proviso that: at least 80 mole % of the 
G groups in the latter formula are tetramethylene radicals and the 
remaining proportion thereof are divalent radicals left after removal of 
hydroxyl groups from a low molecular weight diol having a molecular weight 
not higher than 250; at least 80 mole % of the R.sub.2 groups are 
1,4-phenylene radicals and the remaining proportion thereof are divalent 
radicals left after removal of carboxyl groups from a low molecular weight 
dicarboxylic acid having a molecular weight not higher than 300; the sum 
of the percentages of G groups which are not tetramethylene radicals and 
of the percentage of R.sub.2 groups which are not 1,4-phenylene radicals 
does not exceed 20; and the ester units of the formula 
##STR3## 
form 20 to 90% by weight of the polyester-ester. The invention also 
relates to the processes for the preparation of such polyester-ester 
urethane. 
The preparation of polyester-ester urethanes of the type indicated above is 
described in U.S. Pat. No. 4 186 257. According to the known process a low 
molecular weight polyisocyanate is reacted with a block copolymer 
containing isocyanate-reactive hydrogen atoms. As block copolymers there 
may be used, for instance, copolyether esters and copolyester esters. 
The preparation of copolyether esters is described in, among other 
publications, U.S. Pat. Nos. 3 023 192 and 3 849 515. 
According to the examples mentioned in the afore-mentioned U.S. Pat. No. 4 
186 257 the preparation of polyester-esters is attended with a high degree 
of transesterification, which results in finally obtaining a polyurethane 
having a greatly reduced melting point and a very much increased upper 
limit of the glass transition range [Tg.sub.(e) ] of the low-melting 
polyester segment. 
The present invention provides a polyester-ester urethane having greatly 
improved properties. 
The invention consists in that in a polyester-ester urethane of the type 
indicated above as known the interlinked ester units of the formula 
##STR4## 
and the other ester units interlinked to form a bifunctional polyester or 
polyester amide are present in an amount such that the melting point of 
the polyester-ester urethane is at least 150.degree. C. and when the 
blocks of ester units of the low melting polyester form part of less than 
50% by weight of the total number of ester units, the upper limit of the 
glass transition range [Tg.sub.(e) ] thereof does not exceed +20.degree. 
C. and when said blocks of ester units of the low melting polyester form 
part of more than 50% by weight of the total number of ester units, the 
upper limit of the glass transition range Tg.sub.(e) is not higher than 
-5.degree. C. 
It has been found that a polyester-ester urethane having satisfactory 
properties is generally obtained when the proportion of low-molecular 
weight structural units of the formula 
##STR5## 
calculated as diphenylmethane-4,4'-diisocyanate (MDI) and based on the 
polyester-ester urethane is in the range of 0,5 to 25% by weight. 
Preference is given to a polyester-ester urethane in which the proportion 
of the low molecular weight structural units is in the range of 1 to 15% 
by weight. 
At least 80 mole % of the low molecular weight diol and at least 80 mole % 
of the low molecular weight dicarboxylic acid from which the ester units 
of the formula 
##STR6## 
are derived is formed respectively of 1,4-butanediol and terephthalic 
acid. 
Included among suitable diols (other than 1,4-butanediol) having a 
molecular weight not exceeding 250 are acyclic, alicyclic and aromatic 
dihydroxy compounds. 
Preferred are diols with 2-15, and particularly 5-10 carbon atoms such as 
ethylene, propylene, isobutylene, pentamethylene, 
2,2-dimethyltrimethylene, hexamethylene, and decamethylene glycol, 
dihydroxy cyclohexane, dimethanol cyclohexane, resorcinol, hydroquinone 
and 1,5-dihydroxy naphthalene. 
Especially preferred are aliphatic diols containing 2-8 carbon atoms. 
Included among the bis-phenols which can be used are 
bis(p-hydroxy)diphenyl, bis(p-hydroxyphenyl)methane and 
bis(p-hydroxyphenyl)propane. Suitable dicarboxylic acids (other than 
terephthalic acid) having a molecular weight not exceeding 300 are 
aliphatic, cycloaliphatic or aromatic dicarboxylic acids. 
The term aliphatic dicarboxylic acids as used in the description of the 
invention refers to carboxylic acids having two carboxyl groups which are 
each attached to a saturated carbon atom. If the carbon atom to which the 
carboxyl group is attached is saturated and is in a ring, the acid is 
cycloaliphatic. Aliphatic or cycloaliphatic acids having conjugated 
unsaturation often cannot be used because of homopolymerization. However, 
some unsaturated acids as maleic acid, can be used. 
Aromatic dicarboxylic acids, as the term is used herein, are dicarboxylic 
acids having two carboxyl groups attached to carbon atoms in an isolated 
or fused benzene ring. It is not necessary that both functional carboxyl 
groups be attached to the same aromatic ring and where more than one ring 
is present, they can be joined by aliphatic or aromatic divalent radicals 
such as --O-- or --SO.sub.2 --. 
Representative aliphatic and cycloaliphatic acids which can be used for 
this invention are sebacic acid, 1,3-cyclohexane dicarboxylic acid, 
1,4-cyclohexane dicarboxylic acid, adipic acid, glutaric acid, succinic 
acid, carbonic acid, oxalic acid, azelaic acid, diethyl-malonic acid, 
allyl-malonic acid, 4-cyclohexane-1,2-dicarboxylic acid, 2-ethylsuberic 
acid, .alpha.,.alpha.'-.beta...beta.'-tetramethylsuccinic acid, 
cyclopentanedicarboxylic acid, decahydro-1,5-naphthalene dicarboxylic 
acid, 4,4'-bicyclohexyl dicarboxylic acid, decahydro-2,6-naphthalene 
dicarboxylic acid, 4,4'-methylene-bis-(cyclohexane carboxylic acid), 
3,4-furan dicarboxylic acid and 1,1-cyclobutane dicarboxylic acid. 
Preferred aliphatic and cycloaliphatic acids are cyclohexane-dicarboxylic 
acids and adipic acid. Representative aromatic dicarboxylic acids which 
can be used include phthalic and isophthalic acids, bibenzoic acids, 
substituted dicarboxy compounds with two benzene nuclei such as 
bis(p-carboxyphenyl)methane, p-oxy(p-carboxyphenyl)benzoic acid, 
ethylene-bis(p-oxybenzoic acid), 1,5-naphthalene dicarboxylic acid, 
2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 
phenanthrene dicarboxylic acid, anthracene dicarboxylic acid, 
4,4'-sulfonyl dibenzoic acid, and C.sub.1 -C.sub.12 alkyl and/or ring 
substitution derivatives thereof, such as halo, alkoxy and aryl 
derivatives. Hydroxyl acids such as p(.beta.-hydroxyethoxy)benzoic acid 
can also be used, providing an aromatic dicarboxylic acid is also present. 
Aromatic dicarboxylic acids are a preferred class for preparing the ester 
units of the formula: 
##STR7## 
Among the aromatic acids, those with 8-16 carbon atoms are preferred, 
particularly the phenylene dicarboxylic acids, i.e., phthalic and 
isophthalic acids. 
In view of the melting point and the relatively high crystallization or 
curing rate of the polyester-ester urethane it is preferred that the ester 
units of the formula 
##STR8## 
should be butylene terephthalate units. The procedure for preparing the 
low melting polyesters or polyester amides is known per se and similar to 
that used for preparing high melting polyesters. It may be realized for 
instance by polycondensation of polyfunctional, preferably bifunctional 
alcohols, amino alcohols, hydroxycarboxylic acids, lactones, 
aminocarboxylic acids, cyclic carbonates or polycarboxylic acids. By a 
proper choice of the mixing ratio of the above-mentioned components any 
desirable molecular weight and number and type of terminal groups may be 
obtained. 
As examples may be mentioned polyesters from adipic acid and ethylene 
glycol, butanediol, pentanediol, hexanediol, mixtures of ethylene glycol 
and propylene glycol, hexanediol and methylhexanediol, hexanediol and 
2,2-dimethyl-1,3-propanediol, hexanediol, butanediol or pentanediol or 
polyester amides from hexanediol and piperazine. Also other glycols, such 
as 1,3- or 1,4-cyclohexanediol or 1,3- or 
1,4-bis(hydroxymethyl)-cyclohexane, amino alcohols such as amino ethanol 
or amino propanol may be incorporated into the low melting components. 
The low melting components also may entirely or partly be composed of 
lactones such as substituted or unsubstituted caprolactone or 
butyrolactone. 
Under some circumstances, for instance to increase the melt viscosity of 
the endproduct, it may be recommended to incorporate some small amount of 
higher functional compounds. 
As examples of such compounds may be mentioned trimethylol ethane, 
trimethylol propane or hexane triol. The low melting bifunctional 
components may also be derived from the following acids: glutaric acid, 
pimelic acid, suberic acid, isosebacic acid or ricinoleic acid. Also 
aliphatic dicarboxylic acids having hetero atoms, such as thiodipropionic 
acid may be used in the low melting bifunctional compounds. In addition 
there still may be mentioned cycloaliphatic dicarboxylic acids such as 
1,3- or 1,4-cyclohexane dicarboxylic acid and terephthalic acid and 
isophthalic acid. 
For an essentially better resistance to hydrolysis preference is given to 
polyesters of which the constituents each consist of at least 5 carbon 
atoms. 
As examples may be mentioned adipic acid and 2,2-dimethyl propanediol or 
mixtures of 1,6-hexanediol and 2,2-dimethyl propanediol or 
2-methyl-1,6-hexanediol. In addition to the low melting polyesters or 
polyester amides some other low melting bifunctional compounds may to a 
limited extent be incorporated into the segmented thermoplastic elastomers 
according to the invention. As examples may be mentioned polyalkylene 
glycol ethers having terminal hydroxyl groups as obtained by reaction with 
water, diamines, di- or trifunctional alcohols or amino alcohols. Special 
mention is made here of polytetrahydrofuran obtained by polymerization of 
tetrahydrofuran in the presence of acid catalysts or copolymers thereof 
with small amounts of ethylene oxide and/or propylene oxide. 
The essential advantages of the present invention, such as a very good 
resistance to UV light will be manifest only upon exclusive use of 
polyesters and/or polyester amides, which are therefore preferred. A 
limited percentage of, for instance, polyethylene oxide glycol may be of 
use for improving physical properties, such as swelling in oil. 
Both in view of its being readily obtainable and of other properties of the 
final elastomer preference is given to a polyester-ester urethane whose 
ester units that may form a bifunctional polyester or polyester amide 
having a melting point not higher than 100.degree. C. are entirely or 
substantially derived from polybutylene adipate. 
A polyester-ester urethane having very good properties is also obtained 
when the ester units that may form a bifunctional polyester or polyester 
amide having a melting point not higher than 100.degree. C. are entirely 
or substantially derived from polycaprolactone. The low molecular weight 
structural units of the formula 
##STR9## 
which may be used according to the invention are derived from di- and 
triisocyanates. The diisocyanates may be represented by the general 
formula OCNRNCO, wherein R represents a divalent, aliphatic, alicyclic or 
aromatic group. 
Examples of suitable diisocyanates of the aliphatic type are: hexamethylene 
diisocyanate, dimethyl hexamethylene diisocyanate, trimethyl hexamethylene 
diisocyanate, metaxylylene diisocyanate, paraxylylene diisocyanate, 
tetramethylene diisocyanate. 
When R represents an aromatic group, it may be substituted for instance 
with a halogen, a lower alkyl or a lower alkoxy group. 
Examples of these diisocyanates include: 1-chloro-2,4-phenylene 
diisocyanate, 2,4-toluene diisocyanate, a mixture of 2,4-toluene and 
1,6-toluene diisocyanate, tetramethylphenylene diisocyanate, 
diphenylmethane-4,4'-diisocyanate, metaphenylene diisocyanate, 
paraphenylene diisocyanate, naphthalene-1,5-diisocyanate, 
diphenyl-4,4'-diisocyanate, biphenylmethane-4,4'-diisocyanate, 
biphenyldimethylmethane-4,4'-diisocyanate, benzophenone-4,4'-diisocyanate, 
biphenylether diisocyanate and biphenylsulphide diisocyanate, 
3,3'-dimethyldiphenyl-4,4'-diisocyanate, 
3,3'-dimethoxydiphenyl-4,4'-diisocyanate, 
3,3'-dichlorodiphenyl-4,4'-diisocyanate, 
3,3'-dichlorodiphenyl-4,4'-diisocyanate, benzofuran-2,7-diisocyanate. 
Examples of diisocyanates having an alicyclic group include isophoron 
diisocyanate, dicyclohexylmethane diisocyanate and 1,4-cyclohexane 
diisocyanate. 
It has been found that optimum properties are generally obtained if the 
ratio of the number of --NCO groups of the diisocyanate to the number of 
functional groups of the block polyester-esters is in the range of 1,1 to 
1,5. 
Both with a view to the properties of the end product and simplicity of 
preparation preference is given according to the invention to 
polyester-esters having hydroxyl end groups. 
The invention also relates to processes for the preparation of a 
polyester-ester urethane of the known type indicated in the opening 
paragraph, with the number of interlinked ester units of the formula 
##STR10## 
and the number of other ester units interlinked to form a bifunctional 
polyester or polyester amide are such that the melting point of the 
polyester-ester urethane is at least 150.degree. C. and the upper limit of 
the glass transition range (Tg.sub.(e)) of the low melting polyester 
segment in the case of 50% by weight or more of ester units of the formula 
##STR11## 
does not exceed +20.degree. C. and in the case of less than 50% by weight 
of ester units of the formula 
##STR12## 
is not higher than -5.degree. C. 
One of these processes of the type known from the previously mentioned U.S. 
Pat. No. 4 186 257, a bifunctional polyester having a molecular weight of 
at least 1000 and built up of ester units of the formula 
##STR13## 
wherein both G and R.sub.2 have the same meaning as indicated before, is 
reacted, while in the molten phase, with a bifunctional polyester or 
polyester amide having a molecular weight of at least 1000 and a melting 
point not higher than 100.degree. C., after which the resulting 
polyester-ester is reacted with a low molecular weight coupling agent of 
the formula 
EQU R.sub.1 [NCO].sub.p 
wherein R.sub.1 and p have the afore-indicated meaning, in an amount, such 
that the ratio of the number of --NCO groups to the number of functional 
groups of the polyester-ester is at least 1,0 and not higher than 5, is 
characterized in that before and/or during the preparation of the 
polyester-ester the transesterification catalyst present in one or in both 
polyesters or polyesteramides is entirely or partly deactivated. 
When use is made of a mixture of polyesters or polyester amides having a 
hydroxyl number of 40 or higher the transesterification catalyst will have 
to be deactivated almost entirely in order to obtain a polyester-ester 
urethane according to the invention. 
On the other hand, if the preparation is started from a mixture of 
polyesters or polyester amides having a lower hydroxyl number, 
particularly if use is made of starting products having a relatively high 
molecular weight, then partial deactivation will within a particular space 
of time lead to optimally transesterified block polyester-ester. At a 
given weight ratio of polyesters having a particular molecular weight 
(hydroxyl number) it will not be difficult for a man skilled in the art to 
choose the most favourable conditions which lead to a copolyester-ester 
urethane having optimum properties. 
The present process is advantageously started from a low-melting 
bifunctional polyester or polyester amide having a molecular weight of 
1500 to 2500 and a high-melting polyester of the formula 
##STR14## 
having a molecular weight in the range of 10 000 to 25 000. Preference is 
given then to the use of a high-melting polyester which entirely or 
substantially consists of polybutylene terephthalate having a molecular 
weight in the range of 15 000 to 19 000. 
When, however, use is made of a high-melting polyester having a molecular 
weight in the range of 1500 to 3000, preference is given to its use in 
combination with a low-melting polyester or polyester amide having a 
molecular weight in the range of 10 000 to 20 000. 
For the purpose of transesterification in the preparation of the polyester 
use is generally made of a titanium catalyst or a calcium salt, a 
manganese salt and/or a zinc salt. These salts may be deactivated by 
adding precipitating or complexing agents. Deactivation also may be 
carried out by applying a thermal treatment. It has been found, for 
instance, that when the catalyst used is zinc acetate, it may be 
deactivated by heating to a temperature of at least 200.degree. C. 
Favourable results are particularly found to be obtained when use is made 
of complexing phosphorus compounds, which are also suitable to be used as 
stabilizers in polyesters. 
In this connection reference is made to the phosphites and thiophosphites 
which are described in U.S. Pat. No. 3 039 993, and to the phosphates, 
phosphonates, phosphonic acids and phosphinic acids of the following 
structural formulae: 
##STR15## 
wherein R, R.sub.1, R.sub.2 and R.sub.3 may be the same or different and 
represent a hydrogen atom or a substituted or unsubstituted organic group. 
Examples of suitable substituents are a lower alkyl group, cycloalkyl 
group, alkoxy group, cycloalkoxy group, hydroxyl group and/or a halogen 
atom. If R, R.sub.1, R.sub.2 and R.sub.3 represent an organic group they 
generally do not contain more than 30, and preferably not more than 18 
carbon atoms. As examples may be mentioned alkyl, cycloalkyl, carboalkoxy 
alkyl, aryl, aralkyl and aroxy alkyl. 
As examples of phosphorus compounds that are excellently suitable to be 
used for the present purpose may be mentioned: triphenyl phosphate, 
triphenyl phosphite, triethyl phosphite, tricyclohexyl phosphite, 
tri-2-ethylhexyl trithiophosphite, trieicosyl phosphite, 
tri-o-chlorophenyl phosphite, 2-carbomethoxyethyl dimethyl phosphonate, 
hydroxymethyl phosphonic acid, diphenyl phosphinic acid, carboxymethyl 
phosphonic acid, carbethoxymethyl phosphonic acid, carboxyethyl phosphonic 
acid, tris(triethylene glycol)phosphate and more particularly 
carbethoxymethyl diethyl phosphonate and tri-p-tert. butylphenyl 
phosphite. 
Favourable results are also obtained by using phosphorus compounds of the 
formula: 
##STR16## 
wherein R.sub.1 and R.sub.2 may be the same or different and represent a 
hydrogen atom or an alkyl, cycloalkyl, aralkyl or aryl group each having 
not more than 20 carbon atoms, or the group OR.sub.3, wherein R.sub.3 
represents a metal or ammonium or the same group or the same atom as 
R.sub.1, irrespective of the meaning of R.sub.1. 
Examples of suitable phosphorus compounds include the inorganic acids such 
as orthophosphoric acid, phosphorous acid or hypophosphorous acid; 
phosphinic acid such as methyl phosphinic acid, ethyl phosphinic acid, 
isobutyl phosphinic acid, benzyl phosphinic acid, phenyl phosphinic acid, 
cyclohexyl phosphinic acid or 4-methylphenyl phosphinic acid; phosphonic 
acids such as methyl phosphonic acid, ethyl phosphonic acid, isopropyl 
phosphonic acid, isobutyl phosphonic acid, benzyl phosphonic acid, phenyl 
phosphonic acid, cyclohexyl phosphonic acid, or 4-methylphenyl phosphonic 
acid; the partial esters of said acids, more particularly the C.sub.1-20 
alkyl, cycloalkyl, aryl or aralkyl esters, such as the methyl, ethyl, 
propyl, cyclohexyl, phenyl or benzyl esters; the partial metal salts of 
these acids, of which particularly the metals of the groups I and II of 
the periodic system, such as sodium, potassium, calcium or magnesium; and 
the partial ammonium salts of these acids. 
When use has been made of a salt of calcium, manganese and/or zinc as 
transesterification catalyst, care should be taken that no antimony oxide 
is used as polycondensation catalyst. For in that case the salts can 
hardly, if at all, be deactivated before and/or during the 
transesterification reaction. 
It is generally desirable that the phosphorus compound used for 
deactivation corresponds to at least 0,5 phosphorus atoms per metal atom 
of the transesterification catalyst. 
Favourable results are as a rule obtained when the amount of phosphorus 
compounds used for deactivation corresponds to 1 to 15 phosphorus atoms 
per metal atom, preference being given to using 1 to 5 phosphorus atoms 
per metal atom. 
According to the present invention it is preferred that use should be made 
of polyesters and/or polyester amides prepared in the presence of a 
catalytic amount of a titanium catalyst. The advantage of a titanium 
catalyst is not only its high reactivity, but especially the ease with 
which it can be deactivated. 
Examples of suitable titanium catalysts include esters of titanium acid and 
the neutralized products thereof, hydrogenated hexa-alkoxy titanates of 
magnesium, titanyl oxalates, titanium halides, hydrolysed products of 
titanium halides, titanium hydroxide and titanium oxide hydrate and 
potassium titanium fluoride (K.sub.2 TiF.sub.6). Preference is given to 
alkyl titanates such as tetramethyl titanate, tetraethyl titanate, 
tetrapropyl titanate or tetrabutyl titanate, the neutralized products 
thereof, the hydrogenated magnesium hexa-alkoxy titanates, such as 
hydrogenated magnesium hexabutoxy titanate Mg (HTi[OC.sub.4 H.sub.9 
].sub.6).sub.2, titanyl oxalate, calcium titanyl oxalate, titanium 
tetrachloride, the reaction product of titanium tetrachloride and hexane 
diol and the reaction mixture of titanium tetrachloride and water. Said 
titanium catalysts are used alone or in combination with magnesium acetate 
or calcium acetate. Inorganic titanates such as lanthanum titanate, 
calcium acetate/antimony trioxide mixtures and lithium alkoxides and 
magnesium alkoxides are examples of other suitable catalysts. The amount 
in which they are to be incorporated generally ranges from 0,005 to 0,3% 
by weight, calculated on the components taking part in the reaction. For a 
man skilled in the art it will not be difficult to decide on the amount of 
catalyst to be used for a given system. 
Many of the low-melting polyesters or polyester amides that may be used 
according to the invention are commercially available. Applicant has found 
that they contain no or hardly any transesterification promoting 
catalysts. There is therefore generally no need for these low-melting 
components to be deactivated. The high-melting components, however, are 
generally prepared in the presence of a transesterification promoting 
catalyst. When the deactivating compound is a phosphorus compound, the 
results obtained are generally satisfactory if the phosphorus compound is 
incorporated into the high-melting polyester prior to the reaction process 
and the mixture is kept in the molten state for at least 5 minutes. It has 
been found that satisfactory results are generally obtained when the 
high-melting polyester containing the phosphorus compound is in the molten 
phase for a period of 30 to 60 minutes. The polyester-esters to be used 
according to the invention are usually prepared at a temperature ranging 
between the melting point of the highest-melting component and 290.degree. 
C. An alternative procedure for obtaining a polyester-ester urethane 
according to the invention may be by using a process known from the 
afore-mentioned U.S. Pat. No. 4,186,257 in which a bifunctional polyester 
having a molecular weight of at least 1000 and built up of ester units of 
the formula 
##STR17## 
wherein both G and R.sub.2 have the same meaning as indicated before, is 
reacted, while in the molten phase, with a bifunctional polyester or 
polyester amide having a molecular weight of at least 1000 and a melting 
point not higher than 100.degree. C., after which the resulting 
polesterester is reacted with a low molecular weight coupling agent of the 
formula 
EQU R.sub.1 [NCO].sub.p, 
wherein R.sub.1 and p have the afore-indicated meaning, in an amount such 
that the ratio of the number of --NCO groups to the number of functional 
groups of the polyester-ester is at least 1,0 and not higher than 5, 
characterized in that the number of end groups of the high-melting 
polyester and the low-melting polyester together do not amount to more 
than 700 meq per kg. 
Surprisingly, it has been found that under the above-mentioned process 
conditions when use is made of a mixture of a high-melting polyester and a 
low-melting polyester or polyester amide having a total number of end 
groups not exceeding 700 meq per kg, there is no longer any need for 
deactivation. The advantage of the last-mentioned process especially 
consists in that the amount of polyisocyanate to be used may be reduced to 
a minimum. 
Thus, when use is made of a polyester mixture having 70 meq end groups per 
kg the amount of diisocyanate calculated as MDI need only be as high as 1% 
by weight in the case of an NCO/OH ratio of 1,1. 
The length of time the high-melting and the low-melting polyester or 
polyester amide must react with each other to give an optimally 
transesterified block polyester-ester depends, in part, on the number of 
meq end groups per kg, the amount of transesterification catalyst and the 
composition of the polyesters used. 
It has been found that the last-mentioned process always leads to 
favourable results if the number of end groups both of the high-melting 
polyester and of the low-melting polyester or polyester amide is in the 
range of 110 to 170 meq per kg in either case. 
It has been found that under some circumstances the resistance to 
hydrolysis of the elastomers prepared by the present process is not 
satisfactory. According to the invention this situation may be met by the 
incorporation preferably into the ready product of some stabilizing amount 
of polycarbodiimide. The amount to be incorporated is entirely in 
accordance with the provision described in Netherlands Patent Application 
No. 6 907 958 for the stabilization of polyethyleneterephthalate. 
Another suitable solution to improving the resistance to hydrolysis is the 
incorporation of 0,5 to 5 percent by weight, calculated on the elastomer 
of high molecular weight silicone compounds having --OH, --NH.sub.2 and/or 
--COOH end groups. 
The thermoplastic elastomers obtained by the processes of the present 
invention are excellently suitable to be injection moulded or extruded. 
They have the great advantage of an extraordinarily high resistance to 
oxidative degradation and UV radiation. The hardness of the 
polyester-ester urethanes according to the invention may be varied by 
changing the percentage of high-melting polyester in the copolyester 
ester. A polymer composition having a higher hardness also may be obtained 
by mixing a starting material in the form of a relatively soft 
polyester-ester urethane with a harder type of a polyester-ester urethane, 
a harder copolyether ester mainly containing polybutylene terephthalate as 
hard segment, or polybutylene terephthalate or a copolyester mainly 
containing polybutylene terephthalate. 
The invention will be further described in the following examples. They 
are, however, not to be construed as being limiting in any manner 
whatsoever. 
For the determination of the properties of the polymers prepared as 
described in these examples use was made of the following methods: 
A Du Pont Thermal Analyzer was employed for determining: 
Tg=the temperature range within which the glass transition of the soft 
segment takes place; 
Tg.sub.(e) =the upper limit of the glass transition range (Tg) of the 
low-melting polyester segment, which is taken as the intersection between 
the extrapolated sloping portion and the baseline of the DSC-figure. 
Tm=the temperature range within which the hard segment melts; 
Tm.sub.p =temperature at melting peak(s). 
The measured temperatures are expressed in .degree.C. 
The stress-strain curves were measured on extruded bars 6 mm wide and 1 mm 
thick. The bars were formed in a mould at a temperature which was 
15.degree. C. above the melting point. The rate of specimen extension per 
minute was 500% based on the nominal gauge length. Thus, the following 
values were found: 
--S.sub.100 =stress at 100% elongation (in MPa); 
--S.sub.300 =stress at 300% elongation (in MPa); 
--S.sub.500 =stress at 500% elongation (in MPa); 
--S.sub.300/100 =ratio between stress at 300% elongation and 100% 
elongation; 
--S.sub.500/100 =ratio between stress at 500% elongation and 100% 
elongation; 
--BS=breaking strength (in MPa); 
--BR=elongation at break (in %); 
##EQU1## 
--SR.sub.100-1/2 =stress relaxation (=decrease of stress [%] after 1/2 
hour's stress at 100% elongation); 
--V.sub.100-1/2 =set (%) after 1/2 hour's stress at 100% elongation; 
--V.sub.100-1/2-1/2 =set (%) after 1/2 hour's stress at 100% elongation and 
leaving the material for 1/2 hour in the stressless state.

EXAMPLE I 
Use being made of the same procedure as given in Example 13 of U.S. Pat. 
No. 4 186 257, polybutylene terephthalate (PBTB) having a molecular weight 
of 1500 was prepared by transesterifying dimethyl terephthalate in the 
presence of an excess of 1,4-butanediol and 420 ppm of tetrabutyl titanate 
as catalyst. 
The polybutylene terephthalate thus prepared and an equivalent amount by 
weight of polybutylene adipate (PBA) having a molecular weight of 1850 
were mixed for 1 hour at 240.degree. C. under nitrogen. The polyester 
mixture consequently contained 1207 meq of reactive end groups per kg. 
Subsequently, per 100 g of polyester-ester 16,7 g of 
diphenylmethane-4,4'-diisocyanate (MDI) were added, followed by continued 
stirring for 30 minutes at 230.degree. C. 
The experiment was repeated in such a way that according to the invention 
the polybutylene terephthalate to be coupled to polybutylene adipate was 
heated for 30 minutes to 245.degree. C. in the presence of 1300 ppm of 
diethyl carbethoxy methyl phosphonate (PEE). On conclusion of the 
deactivation reaction the product obtained was mixed, in the 
afore-described manner, with polybutylene adipate to form a 
polyester-ester, after which again 16,7 g of MDI per 100 g of 
polyester-ester were added. On conclusion of the reaction samples of the 
two polymers were examined for their properties. The results are given in 
the table below, polymer A being the polymer prepared in accordance with 
U.S. Pat. No. 4 186 257 and polymer B in accordance with the present 
invention. 
TABLE I 
______________________________________ 
Polymer 
weight ratio A B 
PBTP/PBA 50/50 50/50 
______________________________________ 
Tg (.degree.C.) -18/1 -37/-12 
Tm (.degree.C.) -- 153/217 
Tm.sub.p (.degree.C.) 
108 195 
S.sub.100 (MPa) 2,3 11,0 
S.sub.300 (MPa) 13,5 19,4 
S.sub.500 (MPa) 29,0 29,3 
S.sub.500/100 12,6 2,7 
BS (MPa) 25 38,3 
BR % 575 650 
IS (MPa) 169 290 
SR.sub.1001/2 % 54 39 
V.sub.1001/2 % 83 42 
V.sub.1001/2-1/2 % 
75 27 
______________________________________ 
From the above table it is clear that in the case of non-deactivation of 
the transesterification catalyst of the polybutylene terephthalate having 
a relatively low molecular weight there will be a relatively high degree 
of transesterification, which results in obtaining a polymer which in 
addition to having a far too low melting point is deficient as regards 
several other properties of a product of this composition. Thus, the 
values given for V.sub.100-1/2, V.sub.100-1/2-1/2 and SR.sub.100-1/2 are 
indicative of poor elastomeric properties of polymer A. 
EXAMPLE II 
The starting material in this example was again a polybutylene adipate 
having a molecular weight of 1850. The polybutylene terephthalate was 
prepared in the same manner as indicated in Example I, with the exception 
that the catalyst used consisted of 1700 ppm of tetrabutyl titanate and 
the polycondensation reaction was continued until a molecular weight of 16 
000 was obtained. The polybutylene terephthalate (PBTP) was subsequently 
heated for 30 minutes at 245.degree. C. in the presence of 2500 ppm of 
diethyl carboxymethyl phosphonate. This corresponds to a P/Ti ratio of 
2,4. Next, an equivalent amount by weight of polybutylene adipate (PBA) 
was added to the molten polymer. After the reaction mixture had turned 
clear, there were added 8,5 parts of MDI per 100 parts of polyester, after 
which stirring was continued for 30 minutes at 230.degree. C. The results 
of measuring the various polymer properties are given in the table below. 
TABLE II 
______________________________________ 
Polymer 
weight ratio 
PBTP/PBA 50/50 
______________________________________ 
Tg (.degree.C.) -50/-27 
Tm (.degree.C.) 145/225 
Tm.sub.p (.degree.C.) 
204 
S.sub.100 (MPa) 12,7 
S.sub.300 (MPa) 18,0 
S.sub.500 (MPa) 28,7 
BS (MPa) 51,7 
BR % 700 
IS (MPa) 410 
SR.sub.1001/2 % 31 
V.sub.1001/2 % 34 
V.sub.1001/2-1/2 % 23 
______________________________________ 
EXAMPLE III 
The PBA and the PBTP used here had the same molecular weight as in Example 
II. The weight ratio of PBA to PBTP was 63/37. The PBTP was prepared using 
420 ppm of tetrabutyl titanate as catalyst. 
Five batches were prepared using different amounts of diethyl carbethoxy 
methyl phosphonate (PEE) for deactivation of the transesterification 
catalyst present in the PBTP. The method adopted was the same for each 
batch. After PEE had been added to the PBTP, the resulting mixture was 
heated for 30 minutes to 240.degree. C. Subsequently, PBA was added, after 
which the mixture was heated for 11/2 hours at 240.degree. C. Next, MDI 
was added and heating was continued for 30 minutes at 230.degree. C. 
Of the polymers thus prepared samples were taken on which the properties 
mentioned in the table below were determined. The amount of MDI had been 
set to 9,3 parts per 100 parts of polyester-ester. 
Table III 
__________________________________________________________________________ 
Polymer 
weight ratio 
C D E F G 
PBA/PBTP 63/37 63/37 63/37 63/37 63/37 
__________________________________________________________________________ 
PBTP deactivated prior 
2700 1620 1080 540 0 
to transesterification 
with PEE (ppm) 
Ratio P/Ti 10,0 6,0 4,0 2,0 -- 
Tg (.degree.C.) 
-47/-35 
-46/-34 
-45/-34 
-33/-23 
-32/-2 
Tm.sub.p (.degree.C.) 
222 207 212 160 80 
S.sub.100 (MPa) 
8,8 8,3 7,3 7,3 3,5 
S.sub.300 (MPa) 
15,7 16,0 14,3 12,8 6,3 
S.sub.500 (MPa) 
25,3 25,0 26,0 23,7 13,0 
S.sub.300/100 
1,8 1,9 1,95 1,75 1,80 
S.sub.500/100 
2,9 3,0 3,55 3,2 3,7 
BS (MPa) 31,7 45,8 39,2 39,2 25,3 
BR % 600 700 680 700 700 
IS (MPa) 222 366 306 314 202 
SR % 31 32 32 30 35 
V.sub.1001/2 % 
55 58 42 24 40 
V.sub.1001/2-1/2 % 
30 38 18 17 27 
__________________________________________________________________________ 
The above table clearly shows that under the afore-mentioned reaction 
conditions a polymer having very good properties is obtained at a P/Ti 
ratio between 1 and 5. With the polymers E and F (P/Ti ratios of 4,0 and 
2,0, respectively) the transesterification was optimal. With the polymer G 
the Ti catalyst was not deactivated and transesterification was very 
considerable, which resulted in a greatly decreased melting point, a 
decrease of the stress value at 100% elongation (S.sub.100) and an 
increase in V.sub.100-1/2. 
EXAMPLE IV 
In this example use was made of polycaprolactone (PCL) having a molecular 
weight of 2070 as low-melting polyester and a PBTP having a molecular 
weight of 16 000 prepared in the presence of 420 ppm of tetrabutyl 
titanate as catalyst. Three batches were prepared, each having a different 
weight ratio between the low-melting and the high-melting polyester. 
In each case the NCO/OH ratio was 1,1. The reaction conditions were 
entirely identical with the ones given in Example III. 
The properties measured on the elastomers obtained are given in the table 
below. 
TABLE IV 
______________________________________ 
Polymer 
weight ratio 
PCL/PBTP 63/37 50/50 37/63 
______________________________________ 
MDI (wt. %) 8,4 7,2 5,1 
PEE (ppm) 2500 2000 2250 
Tg (.degree.C.) 
-46/-32 -43/-27 -42/-24 
Tm.sub.p (.degree.C.) 
180 &gt;150 208 
S.sub.100 (MPa) 
6,0 11,7 17,0 
S.sub.300 (MPa) 
10,0 13,3 20,7 
S.sub.500 (MPa) 
17,7 18,2 27,3 
BS (MPa) 34,2 24,7 32,7 
BR % 730 730 700 
IS (MPa) 284 205 262 
SR % 31 31 34 
V.sub.1001/2 % 
21 30 45 
V.sub.1001/2-1/2 % 
15 18 35 
______________________________________ 
The above table clearly demonstrates the influence of the composition on 
various physical properties. Thus, a higher percentage of hard segment 
(=PBTP) is attended with a higher melting point. An increase in the 
percentage by weight of PBTP also leads to higher stress value at 100, 300 
and 500% elongation. 
EXAMPLE V 
Several polyester-ester urethanes were again prepared starting from 
polybutylene adipate having a molecular weight of 1840 and polybutylene 
terephthate having a molecular weight of 16 000 (prepared in the presence 
of 420 ppm of tetrabutyl titanate as catalyst). 
For each batch the NCO/OH ratio was 1,1. Further, not only the weight ratio 
PBA/PBTP was varied; for two compositions it was demonstrated that in a 
further transesterification in the preparation of the polyester-ester 
there is obtained a polyester-ester urethane having a lower melting point, 
but several greatly improved physical properties for the respective 
compositions. The compositions of the elastomers prepared and the 
properties measured on them are summarized in the table below. 
TABLE V 
__________________________________________________________________________ 
weight 
ratio PBA/PBTP 
75/25 63/37 50/50 20/80 
% MDI 10,7 10,7 9,2 9,2 7,8 4,2 
PEE (ppm) 
1250 1250 1000 1000 1250 1250 
Polymer A B C D E F 
__________________________________________________________________________ 
Tg (.degree.C.) 
-42/-23 
-47/-33 
-43/-25 
-33/-23 
-48/-32 
-18/-11 
Tm.sub.p 210 162 208 160 203 215 
S.sub.100 (MPa) 
7,7 4,6 7,2 7,3 12,7 28,3 
S.sub.300 (MPa) 
12,2 10,7 15,3 12,8 18,0 30,8 
S.sub.500 (MPa) 
19,3 24,8 24,3 23,7 28,7 -- 
BS (MPa) 30,7 38,0 40,8 39,2 51,7 45,0 
IS (MPa) 224 277 314 314 410 216 
BR % 630 630 670 700 700 380 
SR % 39 33 33 30 31 22 
V.sub.1001/2 % 
57 53 55 24 34 66 
V.sub.1001/2-1/2 % 
40 22 33 17 23 68 
__________________________________________________________________________ 
Although the polymers B and D clearly have a lower melting point than the 
polymers A and C of the same composition, the former ones display 
distinctly better elastomeric properties, which is particularly manifest 
by the lower values for V.sub.100-1/2-1/2. 
EXAMPLE VI 
The properties of polymer D of Example V are compared with those of a 
polyester-ester urethane of the same composition but prepared from a PBA 
having a relatively high molecular weight (14 000). 
As in the preparation also use was made of a PBTP having a high molecular 
weight (16 000), the catalyst was not deactivated. 
The measured properties were largely the same, except the Tg, which was 
significantly lower with the polymer derived from the high molecular 
weight PBA. 
TABLE VI 
______________________________________ 
weight ratio 
PBA/PBTP 63/37 63/37 
Polymer A B 
______________________________________ 
prepared from PBA having 
1840 14000 
a mol. wt. of 
prepared from PBTP having 
16000 16000 
a mol. wt. of 
NCO/OH 1,1 1,1 
MDI (wt. %) 9,2 1,85 
PEE (ppm) 1000 0 
Tg (.degree.C.) -33/-23 -46/-36 
Tm.sub.p (.degree.C.) 
160 150 
S.sub.100 (MPa) 7,3 6,3 
S.sub.300 (MPa) 12,8 10,0 
S.sub.500 (MPa) 23,7 14,7 
BS (MPa) 39,2 36,7 
IS (MPa) 314 341 
BR % 700 830 
SR % 30 30 
V.sub.1001/2 % 24 30 
V.sub.1001/2-1/2 % 17 20 
______________________________________ 
EXAMPLE VII 
A comparison is given of several polyester-ester urethanes of the same 
composition, but prepared by various processes according to the invention. 
Polymer A was prepared from a high molecular weight PBA and a low 
molecular weight PBTP. 
For each composition the NCO/OH ratio was 1,1. The compositions of the 
starting products and the properties of the polyester-ester urethanes 
prepared therefrom are given in the table below. For each composition the 
weight ratio of PBA/PBTP was 63/37. In the preparation of polymer C the 
transesterification time was longer than in that of polymer B. 
TABLE VII 
______________________________________ 
Polymer 
prepared from: A B C 
weight ratio PBA/PBTP 
63/37 63/37 63/37 
______________________________________ 
PBA (moleculair weight) 
14000 14000 14000 
PBTP (molecular weight) 
3000 16000 16000 
MDI (wt. %) 4,5 1,85 1,85 
PEE (ppm) 1100 0 0 
properties: 
Tg (.degree.C.) 
-47/-33 -50/-40 -46/-36 
Tm.sub.p (.degree.C.) 
175 172 150 
S.sub.100 (MPa) 
6,3 6,7 6,3 
S.sub.300 (MPa) 
11,0 11,3 10,0 
S.sub.500 (MPa) 
14,7 14,0 14,7 
BS (MPa) 22,7 18,7 36,7 
IS (MPa) 211 140 341 
BR % 830 650 830 
SR % 29 30 30 
V.sub.1001/2 % 48 50 30 
V.sub.1001/2-1/2 % 
37 30 20 
______________________________________ 
The above table clearly shows that the properties of the polyesterester 
urethanes according to the invention are very closely related to the 
degree of transesterification. 
EXAMPLE VIII 
For preparing a polyester-ester urethane the same procedure was used as 
described in Example VI (B), except that the PBTP employed had a molecular 
weight of 16 500. The weight ratio PBA/PBTP was 50/50. The amount of MDI 
was 1,8%. 
On this polymer, in the preparation of which no deactivation took place, 
the properties mentioned in the table below were measured. 
TABLE VIII 
______________________________________ 
Polymer PBA/PBTP 50/50 
______________________________________ 
prepared from: 
PBA (mol. wt.) 14000 
PBTP (mol. wt.) 16500 
MDI (wt. %) 1,8 
properties: 
Tg (.degree.C.) -43/-28 
Tm.sub.p (.degree.C.) 
180 
S.sub.100 (MPa) 11,8 
S.sub.300 (MPa) 16,0 
S.sub.500 (MPa) 24,2 
BS (MPa) 40,8 
IS (MPa) 326 
BR % 700 
V.sub.1001/2 % 39 
V.sub.1001/2-1/2 % 
28 
SR % 28 
______________________________________ 
EXAMPLE IX 
A polyester-ester urethane was prepared from PBA (molecular weight 1850) 
and PBTP (prepared in the presence of 420 ppm of tetrabutyl titanate; 
molecular weight 16 000), in a weight ratio PBA/PBTP of 37/63. The 
polyisocyanate used in this example was cyclohexyl diisocyanate (CHDI) [4% 
by weight]. 
The preparation was carried out in the same way as indicated in Example 
III, deactivation being carried out using 650 ppm of PEE. 
The properties measured on the polymer are given in the table below. 
TABLE IX 
______________________________________ 
Polymer PBA/PBTP 37/63 
______________________________________ 
prepared from: 
PBA (mol. wt.) 1850 
PBTP (mol. wt.) 16000 
CHDI (wt. %) 4 
PEE (ppm) 650 
properties: 
Tg (.degree.C.) -55/-38 
Tm.sub.p (C.) 217 
S.sub.100 (MPa) 18,1 
S.sub.300 (MPa) 19,3 
S.sub.500 (MPa) 23,4 
BS (MPa) 33,0 
IS (MPa) 231 
BR % 600 
SR % 34 
V.sub.1001/2 % 52 
V.sub.1001/2-1/2 % 
42 
______________________________________ 
EXAMPLE X 
For preparing a polyester-ester urethane the same procedure was employed as 
in Example IX, except that use was made of 7,2% by weight of a 
trifunctional isoycanate. The trifunctional isocyanate used was the 
reaction product of MDI and the carbodiimide formed from MDI, which is 
marketed by Upjohn under the trade name Isonate 143 L. The properties 
measured on the polymer are given in the table below. They are compared 
with the properties of a polyester-ester urethane prepared in the same 
way, except that use was made of 6,4% by weight of MDI. 
TABLE X 
______________________________________ 
Polymer PBA/PBTP 37/63 
______________________________________ 
prepared from: 
PBA (mol. wt.) 1850 1850 
PBTP (mol. wt.) 16000 16000 
MDI (wt. %) 6,4 -- 
Isonate (wt. %) -- 7,2 
PEE (ppm) 650 650 
properties: 
Tg (.degree.C.) -30/-8 -25/-11 
Tm.sub.p (.degree.C.) 
200 188 
S.sub.100 (MPa) 19,3 19,2 
S.sub.300 (MPa) 22,3 24,3 
S.sub.500 (MPa) 30,0 41,7 
BS (MPa) 33,0 49,0 
IS (MPa) 214 338 
BR % 550 650 
SR % 32 34 
V.sub.1001/2 % 46 42 
V.sub.1001/2-1/2 % 
35 32 
______________________________________ 
EXAMPLE XI 
Polyester-ester urethane was prepared from PBA (molecular weight 1840) and 
PBTP (molecular weight 16000) or from PBTP in which 20% of the 
terephthalic acid had been replaced by isophthalic acid. The weight ratio 
of PBA to the high-melting polyester was 37/63. The polyisocyanate used 
was MDI (6,1% by weight). 
The properties measured on the polyester-ester urethanes prepared are given 
in the table below. 
TABLE XI 
______________________________________ 
polymer with 
isophtalic polymer without 
prepared from acid isophthalic acid 
______________________________________ 
PBA (mol. wt.) 1840 1840 
PBTP (mol. wt.) 
-- 16000 
PBTP in which 20% of 
-- -- 
the terephthalic acid 
had been replaced by 
isophthalic acid 
(mol. wt.) 
MDI (wt. %) 6,1 6,1 
PEE (ppm) 650 325 
S.sub.100 (MPa) 
13,0 17,2 
S.sub.300 (MPa) 
17,9 20,7 
S.sub.500 (MPa) 
32,5 23,0 
BS (MPa) 44,2 29,0 
IS (MPa) 354 263 
BR % 700 800 
SR % 36 32 
V.sub.1001/2 % 40 55 
V.sub.1001/21/2 % 
25 42 
Tg (.degree.C.) 
-27/0 -22/-2 
Tm.sub.p (.degree.C.) 
169 177 
______________________________________ 
EXAMPLE XII 
In this example it is demonstrated that the preparation of the 
polyester-ester urethanes according to the invention at a practically 
equal weight ratio of high-melting to low-melting polyesters and urethane 
groups may be realized by various routes. 
All polyester-ester urethanes in this example were prepared from 37 parts 
of polybutylene adipate and 63 parts of polybutylene terephthalate. 
The preparation of polymer A was started from 40 parts of PBTP (Mol. weight 
16000; deactivated with 1500 ppm of PEE), 37 parts of PBA and 6,7% by 
weight of MDI. The resulting polyester-ester urethane was subsequently 
reacted with 23 parts of polybutylene terephthalate (mol. weight 23000). 
The preparation of polymer B was carried out in the same way as indicated 
in Example III. 
In the process used 63 parts of PBTP (molecular weight 16000; deactivated 
with 1200 ppm of PEE), 37 parts of PBA and 6,3% by weight of MDI were 
reacted with each other. 
The preparation of polymer C was started from 40 parts of PBTP (molecular 
weight 16000) and 23 parts of PBTP (molecular weight 23000), which had 
both been deactivated with 1000 ppm of PEE, together with 37 parts of PBA 
and 6,15% by weight of MDI. 
The properties measured on these polymers are given in the table below. 
TABLE XII 
______________________________________ 
Polymer 
Properties A B C 
______________________________________ 
Tg (.degree.C.) 
-39/-16 -36/-8 -34/-11 
Tm.sub.p (.degree.C.) 
207 206 208 
S.sub.100 (MPa) 
20 20,5 22,5 
S.sub.300 (MPa) 
30 25 29 
S.sub.500 (MPa) 
48 37,5 43 
BS (MPa) 55 37,5 43,3 
IS (MPa) 358 225 260 
BR % 550 500 500 
SR.sub.1001/2 % 
35 32 36 
V.sub.1001/2 % 
39 46 50 
V.sub.1001/2-1/2 % 
25 37 43 
Hardness (Shore D) 
57 55 63 
______________________________________ 
EXAMPLES XIII THROUGH XVI 
In the table below the properties are listed of a number of polyester-ester 
urethanes prepared in the same way as indicated in Example VI B. The table 
gives the molecular weights of the starting products, their weight ratios 
and the number of meq end groups per kg of polyester mixture. 
TABLE XIII 
__________________________________________________________________________ 
mol. meq end 
Exam- 
wt mol. wt 
wt. ratio Tm.sub.p 
groups 
BS IS V.sub.1001/2 
V.sub.1001/2-1/2 
ple PBA PBTP PBA/PBTP 
Tg (.degree.C.) 
(.degree.C.) 
per kg 
(MPa) 
BR % 
(MPs) 
% % 
__________________________________________________________________________ 
XIII 1850 
16000 
10/90 -13/-42 
210 
220 43,3 
230 143 80 78 
XIV 
A 1850 
16000 
27/73 0/+13 
179 
380 65 500 390 56 43 
B 7350 
3000 
27/73 - 3/+18 
194 
560 42 670 327 59 50 
C 1850 
3000 
27/73 + 2/+30 
171 
780 46 525 288 74 42 
XV A 7350 
10600 
50/50 -29/-18 
154 
200 45 650 338 39 33 
B 1850 
10600 
50/50 -26/-9 
176 
640 39 530 247 51 43 
C 1850 
1500 
50/50 -18/+1 
108 
1207 25 575 169 83 75 
XVI 
A 7350 
1500 
63/37 -41/-24 
164 
660 33 530 210 21 15 
B 1850 
23000 
63/37 -33/-13 
60 
715 27 670 208 49 27 
C 1850 
16000 
63/37 -32/-22 
80 
727 25 700 202 40 27 
__________________________________________________________________________ 
The data given in the above table clearly show that when the number of meq 
end groups per kg of polyester mixture is higher than 700 meq per kg, the 
properties of the polymers no longer satisfy the specification according 
to the present application. Thus the Tg.sub.e of the polymer of Example 
XIV-C is 10.degree. C. too high. Of the polymers XV-C and XVI-B and C the 
melting points are unacceptably low.