Note: Descriptions are shown in the official language in which they were submitted.
2136I25
Heat-stable, highly re9ilient, abrasion-resistant polyurethane/
polyester three-block polyadducts, their preparation and their
use
Heat-stable, highly resilient, abrasion-resistant polyurethane/
polyester three-block polyadducts are obtainable by reacting
A) at least one thermoplastic polyester, abbreviated below to
PES, and
B) at least one thermoplastic polyurethane elastomer, referred
to below as TPU, which preferably has a content of free NC0
y~U~ of from 0.5 to 4~ by weight and a total content of NC0
y~Up~ of from 0.75 to 5~ by weight, based in each case on
the total weight of the TPU, and in turn is obtainable by
reacting organic diisocyanates (Ba) with relatively high
molecular weight polyhydroxy compounds (~b) and low molecular
weight chain extenders (~c) with the use of an i~ocyanàte
index greater than 115,
and are used for the production of moldings.
Thermoplastic polymer mixtures comprising at least one PES, for
25 example an aromatic polycarbonate or polyalkylene terephthalate,
and one TPU are known. Such polymer mixtures comprising at least
2 completely reacted thermoplastics, for example (co)polymers,
polycondensates o~ polyadducts, which are usually mixed as dry
granules at room temperature and then compounded by kneading or
30 extruding at elevated temperatures, for example at from 1~0 to
250 C, are also referred to as blends. In blends, the individual
thermoplastics used are present in separate phases without there
being any chemical bond. Where there are sufficiently great dif-
ferences in polarity between the individual plastics phases, the
35 latter can be di~solved out of the blend using suitable solvents.
In contrast, block copolymers, polyadducts, ~uch as TPU, or poly-
condensates, for example polyetheramides, consist of different
segments or phases linked by a chemical bond. TPU consists, for
40 example, of a flexible phase comprising relatively high molecular
weight polyhydroxy compound~, for example of polyester or poly-
ether segments, and of a rigid phase comprising urethane groups,
formed from low molecular weight chain extenders and polyiso-
cyanates. Similarly, polyetheramides contain a polyether flexible
45 phase and a polyamide rigid phase.
`' - 22l36125
~ TPUs are u6ually prepared by reacting a prepared, relatively high
molecular weight, essentially linear polyhydroxy compound with an
organic diisocyanate and a low molecular weight chain extender by
the one-shot or prepolymer process in a suitable apparatus. De-
5 pending on the chemical structure and reactivity of the starting
materials used, the reaction temperature employed and the reac-
tion rate dependent thereon, TPUs having a more or less pro-
nounced block-type binding of the flexible and rigid segments are
obtained. In the case of TPU, a well defined block structure re-
10 sults in, inter alia, high resilience. If the block structure isadversely affected, for example by excessively high reaction tem-
peratures or excessively long reaction times, this leads to a
dramatic deterioration in the mechanical properties of the TPU.
15 As stated above, PES/TPU blends are known. According to
DE-A-26 46 947 ~GB-A 1 513 197), polymer blends having excellent
flexibility at low temperatures and high impact strength are
obtained by thorough mixing of from 50 to 25 parts by weight of
polybutylene terephthalate and from 50 to 75 parts by weight of
20 TPU. To improve the hardness of TPU or the moldability of poly-
butylene terephthalate, according to CA-A 1 111 984 PES/TPU
blends which contain from 5 to 95% by weight of polybutylene
terephthalate and from 95 to 5% by weight of TPU, based on the
total weight, are prepared. Thermoplastic polymer blends having a
25 high modulus of elasticity, a high Shore D hardness, a high
elongation at break and excellent low-temperature impact strength
consist, according to EP-A 0 334 186, of from 70 to 95 parts by
weight of a TPU, prepared from a diisocyanate (Ba), a hydroxyl-
or amino-containing compound (~b) and a short-chain chain
30 extender (~c), the amount of (Bb) being from 5 to 20~ by weight,
based on the sum (Ba) to (Bc), and the ratio of NCO groups of
component (Ba) to the Zerewitinoff-active groups of components
(Bb) and (Bc) being from 0.9 to 1.15, and from 30 to 5 parts by
weight of a thermoplastic terephthalate which may be mixed with
35 at least one further thermoplastic component. EP-A 0 420 016
(CA-A 20 24 715) describes toughened polyurethane/polyester
molding materials which contain from 30 to 90 parts by weight of
TPU, from 5 to 65 parts by weight of PES and from 5 to 30 part6
by weight of at least one graft rubber based on a polybutadiene
40 or on a polyacrylate, the percentages being based on 100 parts by
weight. The disadvantage of these molding materials is that,
although their low-temperature flexibility is considerably
improved, at the same time their heat 6tability is reduced.
3 2136125
- The stated PES/TPU blends furthermore have the disadvantage that,
owing to the use of TPU having an index of, usually, from 90 to
110, no chemical bonding takes place between the PES and TPU
phase.
According to DE-A 41 28 274, thermoplastic materials having high
strength, a high modulus of elasticity and improved heat distor-
tion resistance consi~t of from 99.5 to 60/o by weight of TPU and
from 0.5 to 40% by weight of a PES, which are prepared at from
10 180 to 250 C with the addition of from 0.05 to 5% by weight of an
organic polyisocyanate. The disadvantage of this process is the
high concentration of monomeric, often gaseous di- or triiso-
cyanates in the preparation of the polymer blend. The added mono-
meric di- or triisocyanate undergoes only incomplete reaction
15 during the residence time in, for example, the reaction extruder
and escapes in the form of vapor at the extrusion head.
It is an object of the present invention to prepare materials
having very good heat stability, high resilience and good abra-
20 sion resistance by a process which is technically easy to handle.
We have found that this object i8 achieved, surprisingly, bythree-block polyadducts based on a PES and on a modified TPU, in
which the polyester blocks of the PES and the rigid and flexible
25 segments of the TPU are linked to one another by a chemical bond.
The present invention therefore relates to polyurethane/polyester
three-block polyadducts which are obtainable by reacting
30 A) at least one thermoplastic polyester, preferably polybutylene
terephthalate and/or polyethylene terephthalate, and
B) at least one thermoplastic polyurethane elastomer which in
turn is obtainable by reacting
Ba) organic diisocyanates with
Bb) relatively high molecular weight polyhydroxy compounds
and
Bc) low molecular weight chain extenders,
with the use of an NCo index (isocyanate index) greater than
115, preferably from 116 to 135.
4 2l36l2s
Such TPUs (B) which can be used according to the invention advan-
tageously have a content of free NC0 yLOu~S of from 0-5 to 4% by
weight and a total content of NC0 y-OU~S of from 0.75 to 5% by
weight, based on the total weight of the TPU.
The present invention furthermore relates to a process for the
preparation of the novel TPU/PES three-block polyadducts by
reacting the PES (A) and the special TPU (B) which can be used
according to the invention at from 180 to 300 C, as claimed in
10 claim 9, and the use of the novel TPU/PES three-block polyadducts
for the production of extruded products, preferably of moldings
as claimed in claims 10 and 11.
The novel TPU/PES three-block polyadducts consist of two rigid
15 phase blocks, the PES rigid phase comprising, preferably, poly-
butylene terephthalate, also abbreviated to PBT, or polyethylene
terephthalate, also abbreviated to PET, or of mixtures of PBT and
PET, and the TPU rigid phase, consisting of the urethane rigid
segment, the oligomeric or polymeric reaction product of an
20 organic diisocyanate and a low molecular weight chain extender,
preferably an alkanediol and/or dialkylene glycol, and the
resilient urethane flexible segment, consisting of the relatively
high molecular weight polyhydroxy compound, preferably a
relatively high molecular weight polyesterdiol and/or polyether-
25 diol, which are chemically bonded to one another in the form ofblocks by urethane and/or amide bonds. The urethane or amide
bonds are formed on the one hand from terminal hydroxyl or
carboxyl groups of the PES and on the other hand from terminal
isocyanate groups of the TPU. The novel TPU/PES three-block poly-
30 adducts have a virtually ideal combination of mechanicalproperties, consisting of high heat stability, resilience and
abrasion resistance, the excellent long-term heat stability at
high storage temperatures, for example at from 150 to 170 C, being
particularly noteworthy.
If the PES are reacted with corresponding amounts of TPU which
may be used according to the invention, three-block polyadducts
which have high heat stability, high elongation at break and high
toughness and in which the individual structural blocks are
40 chemically bonded are obtained.
The PES (A) and TPU (B) which may be used in the preparation of
the novel TPU/PES three-block polyadducts correspond to the prior
art.
_ A) PES (A) suitable for this ~ul~ose are described in the
literature and contain at least one aromatic ring which is
bonded in the polycondensate main chain and iB derived from
an aromatic dicarboxylic acid. The aromatic ring may further-
more be substituted, for example by halogen, eg. chlorine or
bromine, and/or by linear or branched alkyl of, preferably, 1
to 4, in particular 1 or 2, carbon atoms, eg. methyl, ethyl,
isopropyl, n-propyl and/or n-butyl, isobutyl or tert-butyl.
The PES (A) may be prepared by polycondensation of aromatic
dicarboxylic acids or mixture~ of aromatic and aliphatic and/
or cycloaliphatic dicarboxylic acids and the corresponding
ester-forming derivatives, such as dicarboxylic anhydrides,
monoe~ters and/or diesters where the alcohol radical is
advantageously of not more than 4 carbon atoms, with
aliphatic dihydroxy cG~.~ounds at elevated temperatures, for
example from 160 to 260 C, in the presence or absence of
esterification catalysts.
Examples of preferably used aromatic dicarboxylic acids are
the naphthalenedicarboxylic acids, isophthalic acid and in
particular terephthalic acid or mixtures of these
dicarboxylic acids. If mixtures of aromatic and
(cyclo)aliphatic dicarboxylic acids are used, up to 10 mol%
of the aromatic dicarboxylic acids may be replaced by
aliphatic and/or cycloaliphatic dicarboxylic acid~ of, advan-
tageously, 4 to 14 carbon atoms, eg. succinic, adipic,
azelaic, sebacic, dodecanedioic and/or cyclohexanedicarboxyl-
ic acid.
Preferred aliphatic dihydroxy compounds are alkanediols of 2
to 6 carbon atoms and cycloalkanediols of 5 to 7 carbon
atoms. 1,2-Ethanediol, 1,4-butanediol, 1,6-hexanediol, neo-
pentylglycol and 1,4-cyclohexanediol or mixtures of at least
two of the stated diols may be mentioned by way of example
and are preferably used.
In particular, the polyalkylene terephthalates of alkanediols
of 2 to 6 carbon atoms have proven excellent as PES (A), so
that preferably PET and particularly preferably PBT or
mixtures of PET and P~T are used.
The relative viscosity of the PES (A) is usually from 0.8 to
1.8, preferably from 1.0 to 1.8, in particular from 1.2 to
1.6, measured in a 0. 5% strength by weight solution in a
` ` 6 2 1 3 6I 2 5
- phenol/1,2-dichlorobenzene mixture having a weight ratio of
1:1, at 25-C.
B) The TPU (B) which may be used for the preparation of the
novel TPU/PES three-block polyadducts may be prepared, for
example, by reacting
Ba) organic, preferably aromatic diisocyanates, in particular
diphenylmethane 4,4'-diisocyanate, with
Bb) at least one relatively high molecular weight polyhydroxy
compound, preferably an essentially bifunctional poly-
hydroxy coll,pound having a molecular weight of from 500 to
8000, in particular polyalkylene glycol polyadipates
where the alkylene radical i8 of 2 to 6 carbon atoms and
which have molecular weights of from 500 to 6000, or
polyoxytetramethylene glycol having a molecular weight of
from 500 to 3200, and
Bc) at least one low molecular weight chain extender, advan-
tageously having a molecular weight of less than 400,
preferably from 60 to 300, in particular 1,4-butanediol,
in the absence or, preferably, presence of
Bd) catalysts and, if required,
Be) additives
at elevated temperatures.
Regarding the TPU components (Ba) to (Bc) and, if required, (Bd)
and/or (Be), the following may be stated: -
35 Ba) exAmrles of suitable organic diisocyanates (Ba) are
aliphatic, cycloaliphatic and, preferably, aromatic diiso-
cyanates. Specific examples are: aliphatic diisocyanates,
such as hexamethylene 1,6-diisocyanate, 2-methylpenta-
methylene 1,5-diisocyanate, 2-ethyl-2-butylpentamethylene
1,5-diisocyanate, 2-ethylbutylene 1,4-diisocyanate or
mixtures of at least two of the stated aliphatic diiso-
cyanates, cycloaliphatic diisocyanates, such as isophorone
diisocyanate, cyclohexane 1,4-diisocyanate, l-methylcyclo-
hexane 2,4- and 2,6-diisocyanate and the corresponding isomer
mixtures, dicyclohexylmethane 4,4'-, 2,4'- and 2,2'-diiso-
cyanate and the corresponding isomer mixtures and, pre-
ferably, aromatic diisocyanates, such as toluylene
7 2136125
~ 2,4-diisocyanate, mixtures of toluylene 2,4- and 2,6-diiso-
cyanate, diphenylmethane 4,4'-, 2,4'- and 2,2'-diisocyanate,
mixtures of diphenylmethane 2,4'- and 4,4'-diisocyanate,
urethane-modified liquid diphenylmethane 4,4'- and/or
2,4'-diisocyanates, 4,4'-diisocyanato-1,2-diphenylethane and
mixtures of 4,4'-, 2,4'- and/or 2,2'-diiso-
cyanato-1,2-diphenylethane, advantageously those having a
4,4'-diisocyanato-1,2-diphenylethane content of at least 95
by weight. Diphenylmethane diisocyanate isomer mixtures
having a diphenylmethane 4,4'-diisocyanate content of more
than 96% by weight and in particular substantially pure
diphenylmethane 4,4'-diisocyanate are preferably uced.
The organic diisocyanates may be replaced in minor amounts,
for example in amounts of up to 3, preferably up to 1, mol~,
based on the organic diisocyanate, by a polyisocyanate having
a functionality of 3 or higher, the amounts of which,
however, must be limited so that polyurethanes which can be
processed by a thermoplastic method are still obtained. A
larger amount of such isocyanates having a functionality of
more than 2 is advantageously compensated by the presence of
compounds having a functionality of less than 2 and posses-
sing reactive hydrogen atoms, 80 that excessive chemical
crosslink;ng of the polyurethane is avoided. Examples of iso-
cyanates having a functionality of more than 2 are mixtures
of diphenylmethane diisocyanates and polyphenylpolymethylene
polyisocyanates, ie. crude MDI, and liquid diphenylmethane
4,4'- and/or 2,4'-diisocyanates modified with isocyanurate,
urea, biuret, allophanate, urethane and/or carbodiimide
group~.
Examples of suitable monofunctional compounds which have a
reactive hydrogen atom and may also be used as molecular
weight regulators are: monoamines, eg. butylamine, dibutyl-
amine, octylamine, stearylamine, N-methylstearylamine, pyrro-
lidone, piperidine and cyclohexylamine, and monoalcohols, eg.
butanol, amyl alcohol, l-ethylhexanol, octanol, dodecanol,
cyclohexanol and ethylene glycol monoethyl ether.
40 Bb) Preferred relatively high molecular weight polyhydroxy com-
pounds (B) having molecular weights of from 500 to 8000 are
polyetherols and in particular polyesterols. However, other
hydroxyl-cont~; n; ng polymers having ether or ester groups as
bridge members, for example polyacetals, such as polyoxy-
methylenes, and especially water-insoluble formal~, for
example polybutanediol formal and polyhexanediol formal, and
polycarbonates, in particular those obtained from diphenyl
21 36125
~ carbonate and 1,6-hexanediol and prepared by transesterifica-
tion, are also suitable. The polyhydroxy compounds must be at
least predominantly linear, ie. must be bifunctional for the
~u.~o~es of the isocyanate reaction. The stated polyhydroxy
c~ Gund~ may be used as individual components or in the form
of mixtures.
Suitable polyetherols can be prepared by known processes, for
example by anionic polymerization with Al kAl 1 metal
hydroxides, such as sodium hydroxide or potassium hydroxide,
or alkali metal alcoholates, such as sodium methylate, sodium
ethylate, potassium ethylate or potassium isopropylate, as
catalysts and with the addition of at least one initiator
molecule which preferably contains 2 bound reactive hydrogen
atoms, or by cationic polymerization with Lewis acids, such
as antimony pentachloride, boron fluoride etherate, etc., or
bleaching earth as catalysts, from one or more alkylene
oxides where the alkylene radical is of 2 to 4 carbon atoms.
Examples of suitable alkylene oxide~ are 1,3-propylene oxide,
1,2- and 2,3-butylene oxide and preferably tetrahydrofuran,
ethylene oxide and 1,2-propylene oxide. The alkylene oxides
may be used individually, alternately in succession or as
mixtures. Examples of suitable initiator molecules are: wa-
ter, organic dicarboxylic acids, such as succinic acid,
adipic acid and/or glutaric acid, N-alkyldialkanolamines, eg.
N-methyl- and N-ethyldiethanolamine, and preferably dihydric
alcohols which may contain bound ether bridges, eg. ethane-
diol, 1,2- and 1,3-propanediol, 1,4-butanediol, diethylene
glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol,
2-methyl-1,5-pentanediol and 2-ethyl-1,4-butanediol. The
initiator molecules may be u~ed individually or a~ mixtures.
Polyetherols obtained from 1,2-propylene oxide and ethylene
oxide and in which more than 50%, preferably from 60 to 80%,
of the OH groups are primary hydroxyl groups and at least
some of the ethylene oxide is arranged as a terminal block
are preferably used. Such polyetherols may be obtained, for
example, by polymerizing first the 1,2-propylene oxide and
then the ethylene oxide with the initiator molecule or first
copolymerizing the total amount of 1,2-propylene oxide as a
mixture with some of the ethylene oxide and then polymerizing
on the remainder of the ethylene oxide, or gradually polymer-
izing first some of the ethylene oxide, then the total amount
of 1,2-propylene oxide and thereafter the remainder of the
ethylene oxide with the initiator molecule.
9 213612~
In particular, the hydroxyl-cont~ n; ng polymers of tetra-
hydrofuran, the polyoxytetramethylene glycols, are very
suitable.
~he essentially linear polyetherols have molecular weights of
from 500 to 8000, preferably fro~ 600 to 6000, and in par-
ticular from 800 to 3500, the polyoxytetramethylene glycols
preferably having molecular weights of from 500 to 3200, in
particular from 600 to 2200. The polyetherols may be used
both individually and in the form of mixtures with one
another.
Suitable polyesterols may be prepared, for example, from
dicarboxylic acids of 2 to 12, preferably 4 to 6, carbon
atoms and polyhydric alcohols. Examples of suitable
dicarboxylic acids are: aliphatic dicarboxylic acids, such as
succinic acid, glutaric acid, adipic acid, suberic acid,
azelaic acid and sebacic acid, and aromatic dicarboxylic
acids, such as phthalic acid, isophthalic acid and tereph-
thalic acid. The dicarboxylic acids may be used individually
or as mixtures, for example in the form of a mixture of
succinic, glutaric and adipic acid. For the preparation of
the polyesterols, it may be advantageous to use the corres-
ponding dicarboxylic acid derivatives, such as dicarboxylic
mono- or diesters where the alcohol radical is of 1 to 4
carbon atoms, dicarboxylic anhydrides or dicarbonyl
dichlorides, instead of the dicarboxylic acids. Examples of
polyhydric alcohols are alkanediols of 2 to 10, preferably 2
to 6, carbon atoms, such as ethanediol, 1,3-propanediol,
1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decane-
diol, 2,2-dimethyl-1,3-propanediol, 1,2-propanediol and
dialkylene glycols, eg. diethylene glycol and dipropylene
glycol. Depending on the desired properties, the polyhydric
alcohols may be used alone or, if required, as mixtures with
one another.
Polyesters of carbonic acid with the stated polyhydric
alcohols, in particular alkanediols of 4 to 6 carbon atoms,
such as 1,4-butanediol and/or 1,6-hexanediol, condensates of
w-hydroxycarboxylic acids, for example w-hydroxycaproic acid,
and preferably polymers of lactones, for example unsubsti-
tuted or substituted ~-caprolactones, are also suitable.
Preferably used polyesterols are polyalkylene glycol poly-
adipates where the alkylene radical is of 2 to 6 carbon
atoms, eg. ethanediol polyadipates, 1,4-butanediol poly-
adipates, ethanediol 1,4-butanediol polyadipates,
2136125
hexanediol neopentylglycol polyadipates, or 1,~-hexane-
diol 1,4-butanediol polyadipates, and polycaprolactones.
The polyesterols have molecular weights of from 500 to 6000,
preferably from 800 to 3500.
Bc) Preferred chain extenders (Bc) having molecular weights of
less than 400, preferably from 60 to 300, are alkanediols of
2 to 12, preferably 2, 4 or 6, carbon atoms and/or alkylene
glycols, eg. ethanediol, 1,6-hexanediol, diethylene glycol,
dipropylene glycol and in particular 1,4-butanediol. However,
diesters of terephthalic acid with glycols of 2 to 4 carbon
atoms, eg. bis-ethylene glycol or bis-1,4-butanediol tereph-
thalate, and hydroxyalkylene ethers of hydroquinone, eg.
1,4-di-(b-hydroxyethyl)-hydroquinone, and polytetramethylene
glycols having molecular weights of from 162 to 378 are also
suitable.
In order to establish the hardness and melt flow index, the
components may be varied in relatively wide molar ratios, the
hardness and the melt viscosity increasing with increasing
content of chain extender (c) while the melt flow index
decreases.
For the preparation of more flexible TPUs (B), for example
those having a Shore A hardness of less than 95, preferably
from 95 to 75 Shore A, for example, the substantially bifunc-
tional polyhydroxy ~-~...pounds (Bb) and alkanediols (Bc) may
advantageously be used in molar ratios of from 1:1 to 1:5,
preferably from 1:1.5 to 1:4.5, so that the resulting
mixtures of (Bb) and (Bc) have a hydroxyl equivalent weight
of more than 200, in particular from 230 to 450, whereas for
the preparation of more rigid TPUs (B), for example those
having a Shore A hardness of more than 98, preferably from 55
to 75 Shore D, the molar ratios of (Bb) to (Bc) are from
1:5.5 to 1:15, preferably from 1:6 to 1:12, BO that the
resulting mixtures of (Bb) and (Bc) have a hydroxyl equiva-
lent weight of from 110 to 200, preferably from 120 to 180.
40 Bd) The TPUs (B) may be prepared in the absence or, preferably,
presence of catalysts (Bd). Suitable catalysts, which in par-
ticular accelerate the reaction between the NCO yL ~U~S of the
diisocyanates (Ba) and the hydroxyl groups of the components
(Bb) and (Bc), are the conventional tertiary amines known
from the prior art, for example triethylamine, dimethylcyclo-
hexyl~ine, N-methylmorpholine, N,N'-dimethylpiperazine,
diazabicyclo[2.2.2]octane and the like, and in particular
`t ` 11 ` 2136125
- organometallic compounds, ~uch as titanates, iron co~pounds,
tin cG...~o~rlds~ eg. tin diacetate, tin dioctoate, tin
dilaurate or the dialkyltin salts of aliphatic carboxylic
acids, such as dibutyltin diacetate, dibutyltin dilaurate or
the like. The catalysts are usually used in amounts of from
0.001 to 0.1 part by weight per 100 parts by weight of the
mixture of polyhydroxy compounds (Bb) and chain extenders
(Bc).
10 In addition to catalysts (Bd), additives (Be) may also be
incorporated into the components. Examples are lubricants,
inhibitors, hydrolysis stabilizers, light stabilizers, heat
stabilizers or stabilizers against discoloration, flameproofing
agents, dyes, pigments, inorganic and/or organic fillers and
15 reinforcing agents.
For this purpose, the additives (Be) may be introduced into the
components or into the reaction mixture for the preparation of
the TPUs (B). In another process variant, the additives (Be) can,
20 however, be mixed with the PES (A) and the TPU (B) and then
melted, or they are incorporated directly into the melt of PES
(A) and TPU (B). The last-mentioned method i5 used in particular
for introducing fibers and/or particulate fillers.
25 When no further information is given below about the additives
which may be used, this information may be obtained from the
technical literature, for example from the monograph by
J.H. Saunders and K.C. Frisch, High Polymers, Volume XVI, Poly-
urethane, Parts 1 and 2 (Interscience Publishers 1962 and 1964),
30 Kunststoff-Handbuch, Volume 7, Polyurethane, 1st and 2nd editions
(carl Hanser Verlag, 1966 and 1983) or DE-A 29 01 774.
For the preparation of the TPUs (B), the components (Ba), (Bb)
and (Bc) are reacted, preferably in the presence of catalysts
35 (Bd) and, if required, additives (Be), in amounts guch that the
ratio of the number of equivalents of NC0 groups of the diiso-
cyanates to the sum of the hydroxyl groups of components (Bb) and
(Bc) is greater than 1.15:1, preferably from 1.16:1 to 1.35:1,
and in particular from 1.20:1 to 1.35:1.
The TPUs ( B) which may be used according to the invention advan-
tageously have a content of free NC0 groups of 0.5 to 4, pre-
ferably from 1.0 to 2.5, % by weight and a total content of NC0
groups of from 0.75 to 5, preferably from 1.25 to 3.5, in par-
45 ticular from 1.25 to 3.0, % by weight, based in each case on thetotal weight of the TPU (B). The total content of NCo groups is
defined as the sum of the free NC0 groups plus the NC0 groups
12 2136125
,~ bound in allophanate, biuret and uretdione groups. The TPUs may
be prepared, for example, by the extruder or, preferably, belt
method by batchwise or continuous mixing of the components (Ba)
to (Bc) and, if required, (Bd) and/or (Be), complete reaction of
5 the reaction mixture in the extruder or on a supporting belt at
from 60 to 250 C, preferably from 70 to 150 C, and subsequent
granulation of the resulting TPU (B). It may be advantageous to
heat the resulting TPUs (B) at from 80 to 120 C, preferably from
100 to 110 C, over a period of from 1 to 24 hours before further
10 processing to the novel TPU/PES three-block polyadducts.
The TPUs (B) are preferably prepared by the belt method, as
stated above. For this purpose, the ~-G".~onents (Ba) to (Bc) and,
if required, (Bd) and/or (Be) are continuously mixed at above the
15 melting point of ~-o".~onents (Ba) to (Bc) with the aid of a mixing
head. The reaction mixture is applied to a support, preferably a
conveyor belt, for example of metal, and is passed at a speed of
from 1 to 20, preferably from 4 to 10, m/minute through a heated
zone having a length of from 1 to 20 m, preferably from 3 to
20 10 m. The reaction temperature in the heated zone is from 60 to
200 C, preferably from 80 to 180 C. Depending on the diisocyanate
content of the reaction mixture, the reaction is controlled by
cooling or heating in such a way that at least 70%, preferably at
least 80~, of the isocyanate groups of the diisocyanates are con-
25 verted and the reaction mixture solidifies at the chosen reactiontemperature. Owing to the free isocyanate groups in the solidi-
fied reaction product, TPUs (B) having a very low melt viscosity
or a high melt index are obtained.
30 For the preparation of the novel TPU/PES three-block polyadducts,
the components PES (A) and TPU (B) may be varied within wide
ratios, for example in PES/TPU weight ratios of from 95:5 to
5:95. In a preferred embodiment, the TPU/PES three-block poly-
adducts contain or, preferably, consist of
A) from 70 to 5, preferably from 50 to 10, % by weight of at
least one PES (A) and
B) from 30 to 95, preferably from 50 to 90, ~ by weight of at
least one TPU (B),
the percentages being based on the total weight.
The novel TPU/PES polyadducts may be prepared by any processes
45 under reaction conditions under which the free NCO groups of the
TPU (B) react with the hydroxyl and/or carboxyl groups of the PES
(A). For example, the storage-stable PES (A) and TPU (B), in
13 2 1 3 6 1 2 5
granular or powder form, may be mixed at up to about 150 C, pre-
ferably from 0 to 50 C, and then melted, or the PES (A) and the
TPU (B) can be mixed directly in the melt.
5 The novel TPU/PES three-block polyadducts are advantageously pre-
pared at from 180 to 300 C, preferably from 190 to 260 C, and in
particular from 220 to 245 C, and in a residence time from 1 to
30, preferably from 2 to 10, minutes using, for example, the
free-flowing, softened or, preferably, molten state of the PES
10 (A) and TPU (B), for example by stirring, treating in a roll
mill, kneading or, preferably, extrusion, for example with the
use of conventional plastication apparatuses, such as Brabender
or Banbury mills, kneaders and extruders, preferably a single-
screw extruder, double-screw extruder or transfer molding/mixing
15 extruder.
In the most advantageous and therefore preferably used prepara-
tion process, the PES (A) and TPU (B) are melted together at from
220 to 245 C, preferably in an extruder, additives (Be) are, if
20 required, incorporated into the melt, the latter is then allowed
to cool and the TPU/PES three-block polyadducts obtained are com-
minuted.
In contrast to TPU and TPU-contA~ n; ng polymer blends, the novel
25 TPU/PES three-block polyadducts are essentially insoluble in sol-
vents conventionally used for polyurethanes, for example
dimethylformamide or dimethylformamide/amine mixtures. In con-
trast to TPU-cont~i ni ng polymer blends, the TPU cannot be dis-
solved out of the novel TPU/PES three-block polyadduct with the
30 stated solvents. Apart from the virtual insolubility of the TPU~
PES three-block polyadducts in the solvents suitable for TPU, the
decrease in the content of free NC0 groups in the end product
also demonstrates the reaction between PES (A) and TPU (B).
35 As stated above, the novel TPU/PES three-block polyadducts have
high heat stability, in particular long-term heat stability, high
resilience and abrasion resistance and can readily be processed
to give moldings, separation into the components PES and TPU
taking place neither in the melt nor in the molding.
Ex~ples
The following components were used for the preparation of the
novel TPU/PES three-block polyadducts and of the TPU/PES blends
45 as C~mrA rative products:
` ` 14 2 1 3 61 2 S
A) Thermoplastic PES
A1: Polybutylene terephthalate having terminal hydroxyl groups
and a relative viscosity of 130, measured in a 0.5%
strength by weight solution in 1:1 (w/w)
phenol/1,2-dichlorobenzene at 25 C (molecular weight about
. 35,000).
A2: Polybutylene terephthalate having terminal hydroxyl groups
and a relative viscosity of 140, measured as described in
A1 (molecular weight about 40,000).
A3: Polyethylene terephthalate having terminal hydroxyl groups
and a relative viscosity of 90, measured as described in
A1.
B) Thermoplastic polyurethane elastomers
Comparative products:
BI: TPU, prepared by reacting a mixture consisting of
1000 parts by weight of a polycaprolactonediol having an
average molecular weight of 2000 (calculated from the
hydroxyl number determined),
133 parts by weight of 1,4-butanediol and
10 parts by weight of 2,2',6,6'-tetraisopropyldiphenyl-
carbodiimide with
520 parts by weight of diphenylmethane 4,4'-diisocyanate
(MDI)
at from 80 to 170 C by the belt method.
The ratio of NCO to OH groups was 1.05:1, corresponding to
an NCO index of 105.
35 BII: TPU, prepared by reacting a mixture consisting of
1000 parts by weight of a polyoxytetramethylene glycol
having an average molecular weight of 1000 (calcu-
lated from the hydroxyl number determined) and
126 parts by weight of 1,4-butanediol with
600 parts by weight of 4,4'-MDI,
similarly to BI.
The ratio of NCO to OH groups was 1.1:1, corresponding to
an NCO index of 100.1.
15 2 1 3 61 2 5
- BIII: TPU, prepared by reacting a mixture consisting of
t 1000 parts by weight of a poly(ethanediol 1,4-butanediol
adipate) having an average molecular weight of 2000
(calculated from the hydroxyl number determined)~
112 parts by weight of 1,4-butanediol and
10 parts by weight of 2,2',6,6'-tetraisopropyldiphenyl-
carhs~;;~;de with
440 parts by weight of 4,4'-MDI,
similarly to BI.
The ratio of NCO to OR groups was 1.008:1, corresponding to
an NCO index of 100.8.
Thermoplastic polyurethanes which may be used according to the
15 invention
Bl: TPU prepared similarly to BI but with the use of 111 parts by
weight of 1,4-butanediol.
The ratio of NCO to OH groups was 1.2:1, corresponding to an
NCO index of 120. The TPU had an analytically determined con-
tent of free NCO groups of 2.0% by weight and a total content
of NCO groups of 2.1% by weight.
25 B2: TPU prepared similarly to BII but with the uQe of 90 parts by
weight of 1,4-butanediol.
The ratio of NCO to OH groups was 1.2:1, corresponding to an
NCO index of 120. The TPU had an analytically determined con-
tent of free NCO groups of 1.7% by weight and a total content
of NCO groups of 1.9% by weight.
B3: TPU prepared similarly to BIII but with the use of 87 parts
by weight of 1,4-butanediol.
The ratio of NCO to OH groups was 1.2:1, corresponding to an
NCO index of 120. The TPU had a content of free NCO groups of
2.4% by weight and a total content of NCO groups of 2.5% by
weight.
B4: TPU prepared by reacting a mixture consi~ting of
1000 parts by weight of a poly(l,4-butanediol adipate)
having an average molecular weight of 2500 (calculated
from the hydroxyl number determined),
68 parts by weight of 1,4-butanediol and
, 16 2136125
; _ 10 parts by weight of
- 2,2',6,6'-tetraisopropyldiphenylcarbodiimide with
360 parts by weight of 4,4'-MDI,
~imilarly to BI.
The ratio of NCO to OH groups was 1.25:1, corresponding to an
NCO index of 125.
B5: TPU, prepared similarly to BI but with the use of 10S parts
by weight of 1,4-butanediol.
The ratio of NCO to OH groups wa~ 1.25:1, corresponding to an
NCO index of 125.
15 B6: TPU, prepared similarly to BII but with the use of 94 parts
by weight of 1,4-butanediol.
The ratio of NCO to OH groups was 1.35:1, corresponding to an
NCO index of 135.
B7: TPU, prepared similarly to BIII but with the use of 96 parts
by weight of 1,4-butanediol.
The ratio of NCO to OH groups was 1.16:1, corresponding to an
NCO index of 116.
Comparative Examples I to III
and Examples 1 to 9
30 Process variant 1
For the preparation of the novel TPU/PES three-block polyadducts
or TPU/PES blends as comparative products, the PES and TPU
granules were thoroughly mixed at 23 C and the mixture was
35 introduced into a twin-screw extruder, melted at from 220 to
240 C, reacted within a residence time of from 2 to 5 minutes and
then extruded into a water bath.
After granulation and drying, the TPU/PES three-block polyadducts
40 or blends were molded with the aid of an injection molding
apparatus at from 210 to 235 C, depending on the hardness, to give
test specimens for which, without further aftertreatment, the
density according to DIN 53 479, the Shore D hardness according
to DIN 53 505, the tensile strength according to DIN 53 504, the
45 elongation at break according to DIN 53 504, the tear propagation
, 17 21~fil2S
_ ~trength according to DIN 53 515 and the abrasion according to
DIN 53 516 were measured.
The tensile strength and elongation at break after storage at
5 elevated temperatures for 500 hours in a through-circulation oven
at 130 C, 150 C and 170 C were also measured.
Process variant 2
- 10 The procedure was similar to that of Process variant 1, except
that a single-screw extruder was u~ed instead of the twin-screw
extruder.
Process variant 3
The TPU was prepared in a reaction extruder in the presence of
the PES.
The components (Ba), (Bb) and (Bc) were thoroughly mixed in
20 amounts corresponding to the high ratio of the number of equiva-
lents of NCO groups to that of OH groups in a twin-screw extruder
and were reacted. The resulting TPU having a high NCO index was
reacted, in the further course of the reaction in the twin-screw
extruder, with added polybutylene terephthalate to give the
25 three-block polyadduct.
The type and amount of the PES (A) and TPU (B) used and the
mechanical properties measured on the test specimens are summa-
rized in Tables I and II below.
Table I
Co~para- Starting ~aterials Proces~ Density ~ard- Ten~ile Elonga- Tear Abra~ion
tive variant nes~ ~trength tion
Example at tion
break strength
P~S TPU [g/c~3J Ishorel lMPal l~] tN/mml tmn3]
A~ount Type A~ount Type
lPart~3 by wt.l lPart~ by wt.]
I~ 50 Al50 8I 21.24 60 D 33 470 117 76
II~ 30 A270 BII 11.165 40 D 16 490 52 71
III~ 33 Al67 8III 31.255 47 D 18 410 61 127
Exa~ple~
1 50 Al50 - 81 21.245 64 D 50 440 149 20
2 30 A270 B2 11.17 50 D 55 600 80 27
3 33 A167 83 31.255 52 D 61 560 95 31
4 30 A270 Bl 21.21 53 D 64 560 99 26 ~_~
A250 84 21.255 63 D 50 480 145 48 C~
6 70 Al30 85 11.27 73 D 57 480 201 22 ~,~
7 95 Al 5 i36 11.31 77 D 52 360 140 46
8 50 A350 ~1 11.22 68 D 51 370 131 32
9 10 Al90 87 21.135 41 D 42 360 39 24
Comr~rative Example9 I to III gave TPU/PES blends having inhomogeneous, poor phase adhesion
Table II
MechAn;cal properties after storage at elevated temperatures for 500 hours in a through-circulation
oven
Examples Tensile strength [MPa] Elongation at break [%]
130-C 150-C 170-C 130-C 150-C 170-C
1 43 39 37 420 420 280
2 31 . 22 23 460 200 120
3 38 28 28 480 430 260
4 44 40 30 500 480 380
38 33 26 410 480 340
6 49 46 44 420 4Z0 2~0
t ~
