Note: Descriptions are shown in the official language in which they were submitted.
CA 02267629 1999-04-14
Yi
H
Preparation of thermoplastic polyurethanes
The present invention relates to processes for. preparing
polyisocyanate polyaddition products by reacting (a) isocyanates ,
with (b) compounds which are reactive towards isocyanates and
have a molecular weight of from 451 to 8000 in the presence of
(c) chain extenders and, if desired, (d) crossiinkers, (e)
to catalysts and/or (f) customary auxiliaries and/or additives and
also to the polyisocyanate polyaddition products which can be
prepared using this process. in particular, the invention relates
to processes for preparing thermoplastic polyisocyanate
polyaddition products by reacting (a.) isocyanates with (b)
.compounds Which are reactive towards isocyanates and have a
molecular weight of from 451 to 8000 and a mean functionality of
from 1.8 to 2.6 in the presence of (c) chain extenders) (e)
catalysts and/or (f) customary auxiliaries and/or additives and
also to the thermoplastic products obtainable in this way.
ao
Polyisocyanate polyaddition producte~ and processes for their
preparation are generally known and have been described many '''
times. A subgroup of these polyaddit:ion products is the
thermoplastic polyisocyanate polyaddition products, generally
Zg .also referred to as thermoplastic polyurethanes (TPUs). These
TPUs are partially crystalline materials and belong to the class
of thermoplastic elastomers. They comprise a partially
crystalline hard block built up fronn the isocyanate and low
molecular weight chain extenders and an amorphous soft block
30 which is typically built up from the. relatively high molecular
weight compounds which are reactive toward isoeyanates,
customarily polyester diols and/or polyether diols. A very good
micromorphological demixing of these: phases is the necessary
prerequisite for the elastic behaviour of the TPUs. The hard
~g block ants, owing to its partial cr,~stallinity, a~ physical
crosslinking which is reversibly broken above the melting point
of the hard block, thus making thermoplastic forming of the
material possible. The soft block i;s in a plastic or liquid state
nt room temperature and is responsilble for the ready
40 deformability of the Tpvs. After deformation, the physical
crosslinking enables elastic recovery to the initial state. The
TPUS have a combination of advantageous material properties such
as low abrasion, good chemical resistance and high flexibility
with simultaneously high strength. In addition, they offer
45 advantages in terms of inexpensive production) for example by the
belt process or extrusion, which can be carried out continuously
or discontinuously, and simple thermoplastic processing.
CA 02267629 1999-04-14
a
variation of the starting components enables products having a
broad range of properties over a wide hardness range to be ~ .
prepared. The heat distortion resistance and thus also the use
properties of the material at temperatures above, in particular,
80~C are determined predominantly by the melt behaviour of the
hard segment block, i.e. the quality of the ~hys~.cal
crossiinking. ' '
Thermoplastic polyurethanes which are prepared on the basis of
(a) MDI, (b) polyester diois and/or polyether diols and (c)
butanedioi partly lose their heat distortion resistance at above
80 ~C, i.e. the material no longer returns to its initial state.
Zn order to be able to use TpUs under static ox dynamic load at
relatively high temperatures, the heat distortion resistance of
i5 the material has to bQ improved over that of .known TPUs.
To improve the modulus of elasticity of TPUs, particularly at
high temperatures, the use of 1,3-pro~panediol as chain extender
~0 has already been described, with the ~TPUs being prepared at an
index of 102 (Forschner et al., Polyurethane 'World Congrese 1997,
page 371). However, the improvement in the modulus of ~lasticity t.
,,.,: .
.. ~,.
of TPUs prepared in this way is still unsatiefaotory, so that
further ways of improving the heat distortion resistance have to
25 be sought.
Further publications describe improvement of the heat distortion
resistance of Tsos (Ep-A 718 335) or improved dimensional
stability of TpU fibres under~load at high temperatures (IT-A 733
30 216). Sp-A 718 335 discloses aromatic chain extenders in
combination with alkane diois having from 4 to 44 carbon atoms
for achieving this aim. =T-A 733 216 ~dsscribes the use of various
chain extenders including 1,3-propane~diol and
1,4-bis(hydroxymethyl) benzene at an index of from 98 to 102. In
35 both these disclosures, the heat distortion resietanoe could be
improved but is not sufficient to meevt the requirements of the
most demanding applications.
=t is an object of the present invention to develop a process for
~0 prepaxing polyisoeyanate polyaddition products, in particular
thermoplastic polyisoc anate of addition
y p y products, hereinafter y
also referred to as thermoplastic pol;Yurethanes, TpUs for short,
by means of the reactions described at the outset, which process
makes it possible to obtain products '.having an improved, i.e.
45 increased, heat distortion resistance.
CA 02267629 1999-04-14
' 3
we have found that this object is achieved by using 1,3- and/or
1,2-propanediol, preferably 1,3-propane~diol) as chain extender
(c) and carrying out the reaction at an index of X104.
The process of the present invention is~ preferably used for ;r'~
preparing TPUB. Processes for preparincE TPtTs are generally known
and differ from processes for preparing polyisocyanate ,
polyaddition products which are not thermopiastioaily processable
mainly by largely avoiding chemical crosslinks in the product end
thus using isoeyanate-reactive compounds (b) which have a mean
functionality of from 1.8 to 2.6, prefelrably from 1.9 to 2.2,
particularly preferably 2, and preferably largely, particularly
preferably completely, omitting crossliLnkers, i.e. compounds v
which are reactive towards isocyanates and have a molecular
weight of x450 and a functionality of a~.3.
According to the present invention, 1,'.3- and/or 1,2-propanediol,
preferably 1,3-propanediol) is used as chain extender.
Z0
In addition to the 1,3- and/or 1,2-pro~panediol, preferably
1) 3-propanediol, preference is given to using at least one . :~~_''
r ~,
aromatic chain extender, i.e. at least one compound having a , .;
molecular weight of x450 g/mol, two groups which are reactive
Z$ towards isocyanates and at least one aromatic :yatem in the . .;
molecule, as (c).
The molar ratio of 1,3- andlor 1,2-pro;panedioi to the compound.or
compounds (b) is usually from 0.1:1 to 8:1, preferably from 1:1
30 to 4:1.
As aromatic chain extenders, preference is given to using
1,4-bis(hydroxymethyi)benzene (eHMB),
1,3-bis(hydroxymethyl)benzane, 1,2-bis(hydroxymethyl)benzene,
$ 1,2-bis(~-hydroxyethoxy)benzene, 1,3-bis(2 -hydroxyethoxy)benzene,
1,4-bis(~ -hydroxyethoxy)benzene (HQEE), diesters of terephthalic
arid with alkanediols having from 2 to~ 4 carbon atoms, e.g.
b~a(ethanedioi) terephthalate or bis(1,4-butanediol)
terephthalate, aromatic diamines such as Z,4- and
4~ 2,6-tolylenediamine, 3,5-diethol-2,4-amd -2,6-tolylenediamine and
primary ortho-dialkyl-, -trialkyl- and/or -tetraalkyl-substituted ;;._
4;4'-diamino--ciiphenylmethanes, piperaz;ine and/or mixtures v
comprising at least two of the aromatic chain extenders
mentioned.
CA 02267629 1999-04-14
' ~ 4
Barticular preference is given to using
1.4-bis(hydroxymethyl)benzene as aromatic chain extender.
The molar ratio of aromatic chain extenders to 1,3- and/or
referabi from.
s 1,2 propanediol is usually from~0.~01:1 to lsl, p y
0.05:1 to 0.55:1.
=n addition to the chain extenders mentioned, it is possible, if-
desired, to use further generally known chain extenders (c) which
will be described by way of example at a later point. Preferably;
the chain extenders used are exclusively 1,2- and/or
1.3- .propanediol with or without at least one aromatic chain
extender.
'
To adiust the hardness and melting point of the TPtJs, the molar
ratios of the formative components (k) and (c) can be varied
within a relatively wide range. Molar ratios of component (b) to
the total of chain extenders (c) of from 1s0.5 to isl2, in
Particular from 1:1 to 1:6.4 have been found to be useful= the
hardness and the melting point of the TPUs increasing with
increasing dioi content.
According to the present invention, the reaction is carried out ~ .;'<k
at.an index of >_104, preferably forms 104 to 120, particularly'. ~:.'a
preferably from 105 to 110. The index is defined as the ratio of
all the isocyanate groups of the component (a) used in the
reaction to the groups which are reactive towards isoeyanates; it
i.e. the active hydrogens, in components (b), (c) and, if used, ' v'~
(d). At an~index of 100, there is one active hydrogen atom, i~:e.
one function which is reactive towards isocyanates. of the
components (b), (c) and, if used, (c!) present. per one isocyanate
group of the component (a).
3s T?i~ isQpyanate index) also known as index, is the actual amount
of isocyanate groups used divided b;r the amount of isocyanate
groups theoretically required for complete reaction of all OH
groups multiplied by 100.
In the following, the starting components and methods of
preparing the preferred TPua are described by way of example.
The components (a), (b). (c) and also (e) and/or (f) which are
customarily used or may be used in the preparation of the TPtTs
are described below by way of example:
CA 02267629 1999-04-14
S
a) Suitable organic isocyanates (a) axe preferably aliphatic.,
cycloaliphatic and in particular ai:omatic diisocyanates.
Specific examples are: aliphatic diisocyanates such as
hexamethylene-1,6-diisocyanate, 2-rnethyipentamethylene
1.5-diisocyanate, Z-ethylbutylene :1.4-diisocyanate or
. mixtures of at least 2 of the C6>a7.kylene diisocyanates , ~;x
mentioned, pentamethylene 1,5-diisocyanate and butylene '~~'
L,4-diisocyanate, cycloaliphatic da.isocyanates such as
1-isocyanato-3,3,5-trimethyl-5-isonyanatomethylcycloh~xane
i0 (isophorone diisocyanate), 1,4- and/or
1,3-bis(isocyanatomethyl)eyclohexane (HXDI)) cyclohexane ,
1,4-diisocyanate, 1-methylcyciohexane 2,4- and
2,6-diisocyanate and also the corresponding isomer mixtures,
dicyclohexylmethane 4,4'-, 2,4'- a;nd 2,2'-diisocyanate and
also the corr~sponding isomer mixtures and preferably
aromatic diisocyanates such as tolylene 2,4-diisocyanate,~
mixtures of tolylene 2,4- and 2,6-diisocyanate,
3,3'-dimathylbiphenyl 4,4'-diisocyanate (TOO=), p-phenylene
- diisocyanate (pDI). m-, p-xylylene diisocyanats (XDI),
Z0 diphenylmethane 4,4'-, 2,4'- and 2,2'-diisocyanate (MD=),
mixtures of diphenylmethane 2,4'- and 4,4'-diisocyanato,
urethane-modified liquid diphenyltr~sthane 4,4'- apd/or
2,4'-diisocyanates, 1,2-di(4-isocyanatophenyl)ethane (EDZ)
and naphthylene 1,5-diisocyanate. preference ie~ given to
Z5 using hexamethylene 1,6-diisocyana~te, diphenylmethane
4,4'-diisocyanate, p-phenylene dii.socyanate (8DI)) v~"
1,2-di(4-isocyanatvphenyl)ethane pED~), naphthylene
1,5- .diisocyanate and 3,3'-dimethy7.biphenyl 4,4'-diisocyanate
(TODD.
'.
b) As compounds (b)-which are reacti~~e towards isocyanates, it
is possible to. use, for example, polyhydroxyl compounds
having molecular weights of from 451 to 8000, preferably from
600 to 6000, in particular from 800 to 4000, and a mean
functionality of from 1.8 to 2.6, preferably from 1.9 to 2.2,
in particular 2. As (b)) preferenne is given to using
polyetherols and/or polyesterols, particularly preferably
polyether diols and/or polyester ~diols.
Hm"~ever, other suitable isocyanate-reactive compounds (b) are
hydroxyl-containing polymers, for example polymethacrylate
diols, polydimethylsiloxane polyols, hydroxyl-containing
polyethylene-butylene copolymers, hydroxyl-containing
hydrogenated polyisvprenes, pviya,cetals such as
polyoxymethylene and water-insoluble formals, e.g.
polybutanediol formal and polyhex:anedioi formal, and
aliphatic polycarbonates) in particular those prepared from ,
CA 02267629 1999-04-14
6
1,6-hexanedivl by transesterification and having the
abovementioned molecular weights. Ths compounds mentioned can
be employed as individual components or in.the form of
mixtures.
The mixtur~s for preparing the TPUs or the TPUs themselves
have to be based at least predominantly on difunctioaal
substances which are reactive towards isocyanates. The TPUs
prepared using these mixtures are thus predominantly
unbranched, i.e. predominantly not crossiinked.
Suitable polyetherols can be prepared by known methods, for
example by addition of alkylene oxides onto at least one
initiator molecule containing at least 2 reactive hydrogen
atoms in bonded form, preferably in the presenos of known
catalysts, for example alkali metal hydroxides such as sodium
or potassium hydroxide or alkali meaal alkoxides such as
sodium methoxide, sodium or potassium ethoxide or potassium
isopropoxide, Lewis acids such as antimony pentachloride,.
boron fluoride etherate, bleaching earth, basic salts of
cesium, e.g. cesium hydroxide. and,~or bass,c salts and/or
hydroxides of alkaline earth metal:a. Preference is given to
using cesium hydroxide and/or calc:~um hydroxide as catalysts
in the alkoxylation in order to obtain polyether polyols
having a low content of unsaturated units. Exampls9 of
alkylene oxides are: ethylene oxid~~, 1,2-propylene oxide,
tetrahydrofuran, 1,2- and 2,3-butylene oxide. Preference is
given to using ethylene oxide and mixtures of 1,2-propylene
oxide and ethylene oxide. The aikylene oxides can be used'
individually, alternately in succession or as a mixture.
Examples of suitable initiator molecules eras water, amino.
alcohols, such as N-alkyidialkanolamines,~for example ,
N-methyidisthanolamine, and preferably diols, e.g.
alkanediols or dialkylene glycols having from 2 to 1Z carbon
35 stoles, preferably 2 to 6 carbon atoms, e.g. ethane diol.
1,3-propanediol. 1,4-butanediol and 1,6-hexanediol. If
desired, mixtures of initiator mol.eculea can also be used.
Further suitable polyetheroia are the hydroxyl-containing,
pol~;rmerization products of tetrahydrofuran
(polyoxytetramethylene glycols). F~referenca is given to using
polyetherols which ire prepared ue:ing 1,2-propylene oxide
and
ethylene oxide and in which~more than 50%) preferably from
60
to 100%, of the os groups are primary hydroxyl groups and,
in
which at least part of the ethylene oxide is arranged as a
45 terminal block; particular preference is given to using
polyoxytetramethylene giycols (po:lytetrahydrofuran). such
polyetherols can be obtained by, Eor example, (first
CA 02267629 1999-04-14
7
polymerizing the 1,2-propylene oxide onto the initiator
molecule and subsequently polymerizing on the ethylene oxide
or first copolymerizing all the i,a-propylene oxide in a
mixture with part of the ethylene oxide and subsequently
polyrneri2ing on the remainder of the ethylene oxide or,
stepwise, first polymerizing part of the ethylene oxide onto
the initiator molecule, then polymerizing on all of the
1,2-propylene oxide and then the remainder of the ethylene
oxide.
The initiator substances and the catalysts can b~ reacted, ~x;,
preferably after removing any water present, with the
propylene oxide and, if desired, further alkylene oxides at
elevated temperature and reduced p:ressure,. in a customary
reactor or autoclave, for example a stirred tank reactor or.
tube reactor with customary facilities for cooling the
reaction mixture. The oataly:t is usually used in an amount
of from 0 to 10 ppm, based on the total formulation, in the
reaction mixture. The alkoxylation is preferably carried out
'at a temperature in the reaction mixture within a range from
70~C to 150oC, particularly preferably from 80~C to lOS~C..The .
reaction is carried out at generally known pressures. The
alkylene oxides can, in general, be added to the reaction
mixture over a period of from 4 to 20 hours, depending on the
Z5 desired molecular weight of the polyoi. preferably, propylene
oxide is added at the beginning of the reaction so that a
block of polyoxypropylene units having a molecular weight of
at least 700 g/mol is added onto the initiator substance. The
reaction time can be from 1 to 8 hours, preferably such that
complete reaction of the alkylene oxides is ensured. After
complete reaction of the, for example, propylene oxide and ~;~~r~w
any further alkylene oxides, polyc~xyethylene units are
particularly preferably added vntc~ the end of the polyol by
addition of ethylene oxid~. Subgeq~uently,~the reaction.
mixture is, as~a rule, cooled, preferably under reduced
pressure, and worked up in a known manner. For example. the
cesium catalyst can be removed frcnn the polyol by adsorption
on, for example, silicates and subsequent,filtration.
Alternatively. the basic catalyst salts, for example the
abovementioned hydroxides, can be neutralized, e.g. by a ,
suitable acid such as phosphoric e~cid) and left in the
polyol. Known stabiliz~rs, e.g. against oxidation, can
subsequently be added to the polyols.
The polyetherols preferably have an unsaturation of leas than
0.07 meq/g, preferably from 0.001 to 0.05 meq/g, particularly
preferably from 0.001 to 0.04 meq/g, in particular from 0.001
CA 02267629 1999-04-14
to 0.01 meq/g. Th~ unsatuxation, which is usually given in
meq per g of polyether polyalcohol, can be determined by
generally known methods, for example by the known method of
Raufmann by bromination of the double bonds and subsequent
S titration with iodine. she unit m~eq/g generally corresponds
to the content of double bonds in mmol per g of polyether
polyaicohol.
Suitable polyesterolea can be prepared, for example, from
l0 dicarboxylic acids having from Z to 12 carbon atoms,
preferably from 4 to 8 carbon atoms, and polyhydric alcohois.' r
r~
Examples of suitable dicarboxyiic 'acids are: aliphatic v ~~:
dicarboxylic acids such as succinic acid, giutaric acid,
suberic acid, azelaic acid, sebbacic acid and preferably
15 adipic acid and aromatic dirarboxylic acids such as phthalic ,x,:
acid, isophthalic acid and terephthalic acid. The
dicarboxylic acids can be used individually or ae mixtures)
e.g. in the form of a succinic, glutaric and adipic acid
mixture. Likewise, mixtures of aromatic and aliphatic
ZO dicarboxylie acids can be used. To prepare the polyesterois,
it may be advantageous to replace.the dicaxboxylic acids with
the corresponding dicarboxylic acid derivatives, e.g.
dicarboxylic esters having from 1 to 4 carbon atoms in the
alcohol radical, dicarboxylic anh,ydrides,or dicarboxylic acid
25 chlorides. Examples of polyhydric alcohols are alkane diola
having from 2 to 10, preferably from 2 to 6, carbon atoms,
e.g. ethanedioi, 1,3-propanediol, 1,4-butanedioi,
1,5-pentanediol, 1.6-hexanediol, 1,10-decanediol,
2,2 -dimethylpropane-1,3~dioi, 3,3-dimethylpentane-1,5-.diol,
30 1,2-propanediol and dialkylene ether glycols such as
diethylene glycol sad dipropylenes glycol. Depending on the
desired properties, the polyhydri.c alcohols can be used alone
or in admixture with one another.
Further suitable polysaterols are esters of carbonic acid
with the abovementioned diola, in particular those having
from 4 to 6 Carbon atoms, e.g. 1,4~butanediol and/or
1,,6-hexanedioi, condensation products of w-hydroxycarboxylic
acids, for example w-hydroxycaproic acid, and preferably
polymerization products of lactones, for example substituted
or unsubstituted w-caprolactones.
Polyesterole which are praferabiy used are alkanediols
Po~.Yadipates having from 2 to 6 carbon atoms in the aikylene
radical, s.g. ethanediol polyadipates, 1,4-butanediol
polyadipatea, ethanediol-1,4-but;snediol polyadipates,
.. ;.:.:
CA 02267629 1999-04-14
1,6-hexanedioi~(neopentyl glycol) polyadipates,
3,3-dimethyl-1,5-pentanediol polyadipates~,
poly(e-caprolactone) and, in particular,
1,6~hexanediol-1,4-butanediol po7.yadipates.
c) As chain extenders (c) which may, if desired, be used in
addition to the chain extenders used according to the present
invention, which additional chain extenders usually hay~,'
molecular weights of s450 g/mol, preferably from 60 to
300 g/mol. preference is given to using aikanediois having
from 2 to 12 carbon atoms, preferably 2,4,6 or 8 carbon
atoms, e.g. ethanediol, 1,6-hexanediol, 1,4-cyclohexanedioi,
1,4-bis(hydroxymethyi)cyclohexane:diol, isosorbide . ~a~~
(1,4:3,6-dianhydro-D-sorbitol),
3-(hydroxymethyl)-5-nitrobenzylalcohol, pyridinedxmethanol
and, in particular, 1,4-butanediol and dialkylene ether
glycol such as diethylene glycol and dipropylene giyool. - . ~''''''~
However, other suitable chain exi:enders are dicarboxylic,
acids such as adipic acid, malonac acid, octanedioic acid,
terephthalic acid and (cyclo)aliphatic diamines such as
piperazine, 4,4'..diaminodicyclohnxylmethane,
3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 1-amino-
3,3,5-trimethyl-5-aminomethylcyc;lohexane. ethylendiamine,
1,2-, or 1,3 propylenediamine, N-~nethyipropylene-1,3-diamine--
Z5 andlor N,N'-di.methylethylenediam.ine.
Additional chain extenders which are particularly preferably
used are alkanediols having from 2 to 10 carbon atoms in the
alkylene radical, in particular 1,4- butanediol and/or
dialkylene glycols having from 4 to 8 carbon atoms.
.., ,.,.;,.;:
e). suitable catalysts which, in particular, accelerate they .
reaction between the NCO groups of the diisocyanates (a) and
the hydroxyl groups of the formative components (b) and (c)
are the catalysts known and customary in the prior art, wiz:
tertiary amines such as triethylamine,
dimethylcyclohexylamine, N-methylmorpholine, '
N,N'-dimethylpiperazine, 2..(dimethylaminoethoxy)ethanoi,
diazabicycio[2.2.2~octane and the like and also, in
particular. organic metal compounds such as titanate est~ra,
iron compounds such as iron(=Ir) aeetylacetonate, tin
compounds such as tin diacetate, tin dioctoate, tin dilaurate
or the dialkyitin salts of aliphatic carboxylic acids, e.g.
,is dibutyltin diacetate, dibutyitin dilaurate or the like. The
catalysts axe usually used in amounts of from 0.0001 to 0.1
CA 02267629 1999-04-14
r
.. . :;.,;;,,
1C
parts by weight per 100 parts by Weight of polyhydroxyl
compounds (b). ,
f) Apart from catalysts, it is also possible to add oustomaxy
auxiliaries and/or additives (e) to the formative components
(a) to (d). Examples which may bs mentioned are
surface-active substances) foam stabilizers, cell regulators,
flame retardants. nucleating agents, oxidation inhibitors,
stabilizers, lubricants and mould release agents, dyes and
pigments, inhibitors, stabilizers against hydrolysis, light,
heat or diecoloratioa, preservatives to prsvont microbial
degradation, inorganic and/or organic fillers, reinforcing
materials and plasticizers. ,''.
. .,_:,,,-,~;
~k'hq
Further details regarding the abovementioned auxiliaries and
additives may be found in the specialist literature.
,;;;::,':v',.
All molecular weights mentioned in this document have the unit
I9/mol].
TpUs can be prepared by known methods by the~ona-shot process
either continuously on belt units or using reaction extruders or '
batchwise by the casting process or by the known prepolymer
process. In these processes, the components (a), (b) and if
desired, (c) which are reacted can bye mixed in succession or
simultaneously) with the reaction commencing immediately.
The resotion is preferably carried out by the one-shot process.
As already mentioned. the reaction mixture comprising (a), (b)
(c) and, if desired, (e) and/or (f) can be reacted by the ~ ~ v;r
extruder process or preferably by the belt process. Speoifically,
the belt process is carried out as hollows:
The formative components (a) to (e) and, if desired (e) and/or '.
(f) are continuously mixed at temperatures above the melting
point of the formative components (.~) to (c) by mean= of a mixing
,10 head. The reaction mixture is appliE~d to a support, preferably a
conveyor belt, and conveyed through a heated zone. The reaction
temperature in the heated zone can be from 60 to 200~C, preferably
from 100 to 180~C, and the residence time is generally fromØ05
to 0.5 hours, preferably from 0.1 to 0.3 hours. After the
4S reaction is complete, the TPU is allowed to cool and is
subsequently commiauted or granulat~sd.
CA 02267629 1999-04-14
y,:'=,~,
=n the extruder process, the formative components (a) to (c) and,
if desired, (e) and (f) are fed individually or as a mixture into
the extruder, reacted at, for example, from 100 to 250°C,
preferably from 140 to 220~C, th~ TPU obtained.is extruded, cooled
and granulated.
The processing of the TPUs prepared according to.the prss~nt
invention, which are usually in the form of granulQS or powder,
to produce the desired cable sheathing,. fibres; mouldings,
linings in automobiles, seals, cable p:Lugs, bellows, hoses,
films. rollers, towing cables, straps «r damping s,lements is
carried out by customary methods, e.g. injection moulding or
extrusion.
=f crosslinked polyisocyanat~ polyaddition products, for example ,
flexible. semi rigid or rigid, compact or cellular, for example '**rt
microceilular, polyurethanes and/or polyisocyanurates ar~
prepared by the process of the present invention, preference is
given to getting compounds (b) having a functionality of from 2
30 to 6, crosslinkers (d) having a functionality of from 3 to 6 and
a molecular weight of x450, preferably from 60 to 300, and in,the
case of foamed polyurethane and/or polyisocyanurate products also
generally known blowing agents, for example wet~r, fluorinated
hydrocarbons and/or (cyclo)alkanes having a boiling point at
Z5 1013 mbar of usually <50°C. The preparation of these products is
generally known.
The polyisocyanate products which can be prepared by the process
of the present invention, in particular the thermoplastic
30 polyurethanes, have the desired incr~ased heat distortion
resistance.
The advantages of the invention are illustrated by the following
examples.
3 5 ~ ~"
Preparation of the TPUs
The Tpus were prepared using the starting components shown in ,
Table 1. The isocyanate-reactive compounds were initially charged
40 in the liquid state at 100°C, in the case of BHMB at 110°C,
and
the isocyanate, which had been preheated to SO~C, was added, and
the components were intensively mixed by stirring. After reaching
a temperature of 115°C, the exothermi~cally reacting mixture was
g5 poured into a dish in which it was cured at 120°C for a residence
time of 20 minutes. After heating at 100°C for 24 hours, thQ
CA 02267629 1999-04-14
lZ
material was granulated and injection moulded at 210~c, when using
sHl~lB at 230~C, to produce test apecirnens .
Table 1 :y,
:
~
. :: :
,
,
:. ~a
Example 1 2 3 4 5 6 7
1,3-propanediol Ig] - 97.5 98.7 99.9 101.1 - -
108HM8 [g) - - - - -
- 115,s
I3QEE (g] - - _ _ - 130.3 -
1,4-eutanediol (g) 108,1 - - - - -
15poly(t-caprolacto- 1000 1000 1000 1000 1000 1000 1000
ne)) mol~cular
weight = 2,000 [g]
Elastoetab~ HOl [g] 8 8 8 8 8 8 8
Z~4,4'-MDI (g] 456 451 9;69 487 505 313 360
Il7dex 106 100 1.03 106 109 106 106
,;
~SElastoBtab~: hydrolysis a
stabilizer base:d carbodiimide
on (Elaetogran
Gaibii )
Examples 4 and s are according to preseat
examples the invention.
W
The TPLJS prepared to their
in the examples were determine
tested
30properties, in particular regards heat distortion
as the
resistance. The properties the pocim~ens
of test are
s indicated
in
Tabla 2.
d0
CA 02267629 1999-04-14
i3
Table 2
Exam-DensityShore Vicat Abra- tear props-TensileElon-
Ple. A Temperatu-siom gation re- atreagthga- ~:'u
hard- re sistance tion . ~:;.~,:
ness at
.'... .:.,~.':,'4
break
I9/cm~] [~C] (mtn3J(p/mm) (lv/amv]
( J
1 1.18 84 l44 35 62 44 510
2 1.17 82 138 25 58 41 420
3 1.17 82 156 25 56 42 400
4 1.18 84 160 27 67 44 480
5 1.18 84 160 24 62 48 510
6 1.18 83 128 45 52 44 590
7 1.18 81 144 47 59 30 580
The significantly improved heat distortion resistance of the
samples 4 and 5 which are according to the present invention is
shown particularly clearly by the vicat temperatures (see also
Figure 1]. The Vicat temperature indicates the temperature at
which a pin which is loaded with a weight of 10 N and has a . :,~;;.,'
5 contact area of 1 mma has penetratQd to a depth of 1 mm into the lw
specimen which is heated at iZO~C/h. This mesaurement is carried
. out in accordance with DIN EN ISO 306.
. :;.;..
The properties of the TPUs according t;o the present invention are
shown in Table 2. These data support the assessment of the prior
art given at the outset. Only the TpUa; prepared according to the
present invention have a heat distortion resistance which meets
the requirements of the most demanding applications. ~t is
considerably improved compared to that. of the comparative
3s samples. In addition, the aampies 4 and 5 have significantly
unproved values for the abrasion and tear propagation resistance,
partic~lariy compared to the samples which wore prepared using
-: sxclusively aromatic chain extenders (Examples 6 and 7). The
priparation of the TPUs at a known, lc~w index leads to a
~p diterioration in the heat distortion =resistance, the tensile
strength, the tear propagation resistance and the elongation at
break (Examples 2 and 3). TpU prepared. using Only 1,4-butanediol
as chain extender displays) in particular) a poorer heat
distortion resistance and increased abrasion. v 4
The improved heat distortion resistance resulting from the use of
a relatively high index and 1,3-propan,ediol as chain extender can
CA 02267629 1999-04-14
14
also be seen from the shape of the vicat curve (cf. Figure 1)..
=t can clearly be seen that the penetration of,the test pin is
shifted to a higher temperature in the case of a higher index.
It is~thus demonstrated that the object, of the present invention,
namely to provide polyisocyanate polyaddition products, in
particular TBUs, having improved props:'ties, in particular an
i0 improved heat di.gtortion resistance, hays been able to be achieved
by the technical teachings of the present invention. The TPVs.
according to the present invention have: significantly improved
properties compared to known TPVs.
..,
;v ,,
~0
~0
43
