HK1069839B - Polyurethane elastomers, method for the production thereof and their use - Google Patents

Description

Polyurethane elastomer, preparation method and application thereof

Technical fieldDomain

The invention provides polyurethane elastomers (PU elastomers), a process for their preparation using special catalyst mixtures and their use, in particular for the production of shoe soles.

PU elastomers have long been known and are used exclusively for a wide variety of applications (US-A5952053). To control the rate of polymerization, a large variety of different metal catalysts have been studied and employed. In addition to the widely used organotin compounds, they include organic compounds or organic salts of various other elements such as lithium, titanium and bismuth.

The use of lithium salts of organic acids is occasionally reported. Mixtures of lithium carboxylates, i.e. lithium neodecanoate, lithium octanoate, lithium stearate or lithium naphthenate, with zinc carboxylates are described, for example, in U.S. Pat. No. 4, 4256847 as efficient catalyst combinations for rigid foams. In this way, high activity of lithium is achieved. Other patents list lithium as the only metal catalyst for catalyzing the PU reaction. In U.S. Pat. No. 3, 4107069, lithium carboxylates are used as stable gel catalysts for rigid PU foams. US-a 3108975 uses them as catalysts for hard and soft and microporous and non-porous polyurethanes. Lithium carboxylates are also widely used as trimerization catalysts. In fact, in U.S. Pat. No. 4, 3634345, a humidity-insensitive, readily soluble salt of an aromatic carboxylic acid is used for the production of PU resins; in U.S. Pat. No. 6, 3940517, a lithium aliphatic carboxylate is used as PU foam, while in U.S. Pat. Nos. 6,27308 and 5955609, the good controllability of the trimerization is used for the synthesis of PU foams and prepolymers. The same procedure is used in DE-A59101001 for the production of rigid foams. Finally, in US-a 2894919, lithium carboxylates, i.e. lithium stearate and lithium octoate, are used as catalysts to produce exclusively resilient, soft PU foams.

Organic titanium compounds have been used as catalysts in the synthesis of polyurethanes since the sixties of the last century, for example, those listed in US-a 5902835. Titanium compounds of this type are primarily titanium carboxylates (U.S. Pat. No. 3, 5162382), alkyl titanates (Saunders, J.H.; Frisch, K.C.; polyurethanes-chemistry and technology (1962), London, Vol.I., p.168, JP 2001/026629, JP 5097952) and diketonate titanium and titanium beta-ketoesters (U.S. Pat. No. 3, 5902835, DE-A19626007, WO 98/15585, chemical abstracts Vol.108: 56652). They are used as blowing (expansion) and gelling catalysts. The application fields of the polyurethane foam extend from water foaming PU foam plastics and mechanical foaming and thermal curing PU foam plastics to PU surface coatings and even RIM (reaction injection molding) systems for soft PU foam plastics.

With certain exceptions (e.g. Luo, S. -G.; Tan, H. -M.; Zhang, J. -G.; Wu, Y. -J.; Pei, F. -K.; Meng, X. -H.; journal of applied Polymer science (1997)65(6), pp.1217-1225), carboxylates (CA-A2049695, DE-A19618825, US-A5792811, WO 2000/47642) are mainly used among all organobismuth compounds. In addition, organothiolates of bismuth (WO 95/29007, U.S. Pat. No. 3, 5910373, U.S. Pat. No. 3, 6190524) are used as latent catalysts. The use of bismuth compounds together with organozinc (WO96/20967, US-A5910373) or with tin compounds (WO 98/14492, US-A6001900, US-A5859165, US-A6124380, WO 2000/46306, US-A6190524) is also widespread. The field of application of bismuth catalysts mentioned in this section is mainly in the area of surface coatings.

Catalyst combinations containing a large number of organic compounds of the elements lithium, titanium or bismuth, in addition to the combinations with other metal catalysts already mentioned, for example tin and zinc compounds, are also found in the literature. Patent specifications US-a 5952053, WO 2000/46306 and US-a 5952053 list, for example, combinations of lithium with bismuth compounds, whereas US-a 5902835 mentions that organotitanium compounds can be combined with bismuth compounds, however, these metal catalyst combinations thus obtained do not exhibit special effects.

In particular shoe soles, are an important field of application for PU elastomers. The catalyst system used in its production must provide excellent shoe sole processability. Specifically, this includes short demold times and high demold hardness values, as well as long cream times to ensure that every corner of the mold is filled. The catalyst must also promote the development of good end properties, for example, high end hardness values and low puncture expansion (punclunk expansion) values under repeated flexural stresses. Commercial organotin catalysts do not meet this set of requirements.

It is therefore an object of the present invention to provide PU elastomers having high final hardness values and low puncture expansion values under repeated flexural stresses, and a production process which makes it possible to achieve short demolding times, high demolding hardness values and long cream times.

Surprisingly, this object is achieved by means of a special catalyst combination comprising an organolithium and a titanium compound or an organolithium, titanium and bismuth compound. In the case of a three-component mixture, the required catalyst concentration can also be significantly reduced compared to a two-component mixture while the other effects are the same, thus bringing additional advantages in terms of toxicology and economy.

The present invention provides polyurethane elastomers obtainable by reacting the following components a) to e) in the presence of f) to k):

a) organic di-and/or polyisocyanates with

b) At least one polyether polyol having a number average molecular weight of 800 to 25,000g/mol, preferably 800 to 14,000g/mol, particularly preferably 2,000 to 9,000g/mol, and an average functionality of 1.6 to 2.4, preferably 1.8 to 2.4,

c) optionally, further polyether polyols other than b) having a number average molecular weight of 800 to 25,000g/mol, preferably 800 to 14,000g/mol, particularly preferably 2,000 to 9,000g/mol, and an average functionality of 2.4 to 8, preferably 2.5 to 3.5,

d) optionally a polymer polyol containing from 1 to 50% by weight, preferably from 1 to 45% by weight, of filler, and having a hydroxyl number of from 10 to 149 and an average functionality of from 1.8 to 8, preferably from 1.8 to 3.5, relative to the polymer polyol,

e) optionally, a low molecular weight chain extender having an average functionality of 1.8 to 2.1, preferably 2, a molecular weight of 750g/mol or less, preferably 18 to 400g/mol, particularly preferably 60 to 300g/mol, and/or a crosslinker having an average functionality of 3 to 4, preferably 3, and a molecular weight of up to 750g/mol, preferably 18 to 400g/mol, particularly preferably 60 to 300g/mol,

f) an amine catalyst and a catalyst mixture consisting of,

g) at least one organic titanium and/or zirconium compound

h) And at least one lithium salt of an organic carboxylic acid

i) And optionally additionally at least one bismuth salt of an organic carboxylic acid,

j) optionally a blowing agent and

k) optionally an additive(s) is (are),

wherein the amount of substance n of titanium ions in component g)_TiAnd/or the mass n of zirconium ions_ZrWith the amount of substance n of the lithium ions in component h)_LiThe ratio of (a) to (b) is 0.2 to 4, preferably 0.43 to 1.5, and if component i) is used, the amount of substance n of bismuth ions in component i) is_BiWith mass n of substance_TiAnd/or n_ZrAnd n_LiThe ratio of the sum of the amounts is 0.0001 to 0.53, preferably 0.0001 to 0.24, particularly preferably 0.0001 to 0.15.

The PU elastomers are preferably produced by the prepolymer process, wherein in a first step an polyaddition product having isocyanate groups is conveniently prepared from at least a portion of the polyether polyol b) or a mixture thereof with the polyol component c) and at least one diisocyanate or polyisocyanate a). In a second step, solid PU elastomers can be produced from prepolymers having such isocyanate groups by reaction with low molecular weight chain extenders and/or crosslinkers d) and/or the remainder of the polyol component b) and optionally c). If water or another blowing agent or mixtures thereof are additionally used in combination in the second step, microcellular PU elastomers can be produced.

Aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, such as those described by W.Siefken in Justus Liebigs Annalen der Chemie 562, pp.75 to 136, are suitable as starting components a) for the process of the invention, for example those of the general formula,

Q(NCO)_n

wherein n represents 2 to 4, preferably 2, and Q represents an aliphatic hydrocarbon group of 2 to 18, preferably 6 to 10 carbon atoms; a cycloaliphatic hydrocarbon group of 4 to 15, preferably 5 to 10 carbon atoms; an aromatic hydrocarbon group of 6 to 15, preferably 6 to 13 carbon atoms; or an araliphatic hydrocarbon group of 8 to 15, preferably 8 to 13, carbon atoms; suitable examples include ethylene diisocyanate, 1, 4-tetramethylene diisocyanate, 1, 6-Hexamethylene Diisocyanate (HDI), 1, 12-dodecane diisocyanate, cyclobutane-1, 3-diisocyanate, cyclohexane-1, 3-and-1, 4-diisocyanate and any mixtures of these isomers, 1-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane, 2, 4-and 2, 6-hexahydrotoluylene diisocyanate and any mixtures of these isomers, hexahydro-1, 3-and 1, 4-phenylene diisocyanate, perhydro-2, 4 '-and-4, 4' -diphenylmethane diisocyanate, 1, 3-and 1, 4-phenylene diisocyanate, 1, 4-Durene Diisocyanate (DDI), 4 ' -stilbene diisocyanate, 3 ' -dimethyl-4, 4 ' -biphenyl diisocyanate (TODI), 2, 4-and 2, 6-Toluene Diisocyanate (TDI) and any mixtures of these isomers, diphenylmethane-2, 4 ' -and/or-4, 4 ' -diisocyanate (MDI), or naphthalene-1, 5-diisocyanate (NDI).

Other examples include: triphenylmethane-4, 4' -triisocyanate, polyphenyl polymethylene polyisocyanates, for example, obtained by aniline-formaldehyde condensation followed by phosgenation of acid esters and described, for example, in GB-A874430 and GB-A848671; meta-and para-isocyanatophenylsulfonyl isocyanates according to U.S. Pat. No. 4, 3454606; perchlorinated aryl polyisocyanates, as described, for example, in U.S. Pat. No. 4, 3277138; polyisocyanates having carbodiimide groups, as described, for example, in U.S. Pat. No. 4, 3152162 and in DE-A2504400, DE-A2537685 and DE-A2552350; norbornane diisocyanate according to U.S. Pat. No. 4, 3492301; polyisocyanates having allophanate groups, as described, for example, in GB-A994890, BE-A761626 and NL-A7102524; polyisocyanates having isocyanurate groups, as described, for example, in U.S. Pat. No. 3, 30019731, in DE-A1022789, DE-A1222067 and DE-A1027394 and even DE-A1929034 and DE-A2004048; polyisocyanates having urethane groups, as described, for example, in BE-A752261 or U.S. Pat. No. 3, 3394164 and DE-A3644457; polyisocyanates having acylated urea groups, according to DE-A1230778; polyisocyanates having biuret groups, as described, for example, in U.S. Pat. Nos. 3,3124605, 3, 3201372 and 3124605 and GB-A889050; polyisocyanates prepared by telomerization, as described, for example, in U.S. Pat. No. 4, 3654106; polyisocyanates having ester groups, as described, for example, in GB-A965474 and GB-A1072956, in U.S. Pat. No. 3, 3567763 and in DE-A1231688, the reaction products of the above-mentioned isocyanates with acetals, according to DE-A1072385; and polyisocyanates containing polymerized fatty acid esters, according to U.S. Pat. No. 3, 3455883.

Distillation residues having isocyanate groups obtained in the industrial isocyanate production, optionally dissolved in one or more of the above-mentioned polyisocyanates, may also be used. Any mixtures of the above-mentioned polyisocyanates may also be used.

It is preferred to use polyisocyanates which are readily available industrially, for example 2, 4-and 2, 6-toluene diisocyanate and any mixtures of these isomers ("TDI"), 4 ' -diphenylmethane diisocyanate, 2 ' -diphenylmethane diisocyanate and polyphenyl polymethylene polyisocyanates, for example those prepared by aniline-formaldehyde condensation followed by phosgenation ("crude MDI"), and polyisocyanates having carbodiimide groups, uretonimine groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups ("modified polyisocyanates"), in particular from 2, 4-and/or 2, 6-toluene diisocyanate or from 4, 4 ' -and/or 2, 4' -diphenylmethane diisocyanate derived such modified polyisocyanates. Mixtures of naphthalene-1, 5-diisocyanate and the polyisocyanates mentioned are also very suitable.

However, prepolymers having isocyanate groups which are prepared in this way are particularly preferably used in the process of the invention: that is, from at least a portion of the amount of polyol component b) and/or c) and/or chain extenders and/or crosslinkers e) with at least one aromatic diisocyanate selected from TDI, MDI, TODI, DIBDI, NDI, DDI, preferably with 4, 4' -MDI and/or 2, 4-TDI and/or 1, 5-NDI, to give an polyaddition product having urethane and isocyanate groups and having an NCO content of from 10 to 27% by weight, preferably from 12 to 25% by weight.

As mentioned above, mixtures of b), c) and e) can be used to prepare prepolymers containing isocyanate groups. According to a preferred embodiment, however, the isocyanate group-containing prepolymer is prepared without the use of chain extenders or crosslinkers e).

The prepolymer having isocyanate groups may be prepared in the presence of a catalyst. However, it is also possible to prepare prepolymers having isocyanate groups without catalysts and to incorporate the catalysts into the reaction mixture only for the production of PU elastomers.

Polyether polyols b) or c) suitable for producing the elastomers according to the invention can be produced in a known manner, for example by means of DMC-catalyzed polymerization intercalation (polyinsertion) of alkylene oxides, by means of anionic polymerization of alkylene oxides in the presence of alkali metal hydroxides or alkali metal alkoxides as catalysts and with addition of at least one initiator molecule containing active hydrogen in the form of 2 to 6, preferably 2 to 4, bonds, or by means of cationic polymerization of alkylene oxides in the presence of Lewis acids, such as antimony pentachloride or boron fluoride etherate. Suitable alkylene oxides contain 2 to 4 carbon atoms in their alkylene group. Examples are tetrahydrofuran, 1, 2-propylene oxide, 1, 2-or 2, 3-butylene oxide; ethylene oxide and/or 1, 2-propylene oxide are preferably used. The alkylene oxides can be used individually, either sequentially or as a mixture. Mixtures of 1, 2-propylene oxide and ethylene oxide are preferably used, wherein ethylene oxide is used in an amount of 10 to 50% as ethylene oxide end blocks ("EO capping") so that the resulting polyol has more than 70% primary hydroxyl end groups. Examples of initiator molecules include water or di-or trihydric alcohols, such as ethylene glycol, 1, 2-and 1, 3-propanediol, diethylene glycol, dipropylene glycol, ethylene-1, 4-diol, glycerol, trimethylolpropane, etc. Suitable polyether polyols, preferably polyoxypropylene polyoxyethylene polyols, have an average functionality of from 1.6 to 2.4, preferably from 1.8 to 2.4, and a number average molecular weight of from 800g/mol to 25,000g/mol, preferably from 800 to 14,000g/mol, particularly preferably from 2,000 to 9,000 g/mol.

Difunctional or trifunctional polyether polyols having a number-average molecular weight of 800 to 25,000, preferably 800 to 14,000g/mol, particularly preferably 2,000 to 9,000g/mol, are particularly preferably used as components b) or c) in the preparation of the elastomers according to the invention.

Suitable as polymer polyols d) are, in addition to the abovementioned polyether polyols, polymer-modified polyether polyols, preferably graft polyether polyols, in particular those based on styrene and/or acrylonitrile which are produced by in situ polymerization of acrylonitrile, styrene or preferably mixtures of styrene and acrylonitrile in a weight ratio of, for example, 90: 10 to 10: 90, preferably 70: 30 to 30: 70, and polyether polyol dispersions which contain, as disperse phase, conventionally present in an amount of from 1 to 50% by weight, preferably from 1 to 45% by weight, relative to the polymer polyol, for example: inorganic fillers, Polyurethanes (PHD), polyhydrazides, polyurethanes containing tertiary amino groups in bonded form and/or melamine.

For the preparation of the PU elastomers according to the invention, it is additionally possible to use as component e) low molecular weight difunctional chain extenders, trifunctional or tetrafunctional crosslinkers or mixtures of chain extenders and crosslinkers.

Such chain extenders and crosslinkers e) are used to improve the mechanical properties, in particular the hardness, of the PU elastomers. Suitable chain extenders are, for example, alkanediols, dialkylene glycols and polyalkylene polyols, and also crosslinking agents, for example trihydroxy or tetrahydroxy alcohols and oligomeric polyalkylene polyols having a functionality of from 3 to 4 and conventionally exhibiting a molecular weight of less than 750g/mol, preferably from 18 to 400g/mol, particularly preferably from 60 to 300 g/mol. Alkanediols having 2 to 12, preferably 2, 4 or 6, carbon atoms, such as ethylene glycol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, in particular 1, 4-butanediol, dialkylene glycols having 4 to 8 carbon atoms, such as diethylene glycol and dipropylene glycol, and polyoxyalkylene glycols are preferred as chain extenders. Also suitable are branched-chain and/or unsaturated alkanediols having traditionally not more than 12 carbon atoms, for example 1, 2-propanediol, 2-methyl-1, 3-propanediol, 2-dimethyl-1, 3-propanediol, 2-butyl-2-ethyl-1, 3-propanediol, 2-butene-1, 4-diol and 2-butyne-1, 4-diol, diesters of terephthalic acid with diols having from 2 to 4 carbon atoms, for example terephthalic acid-bis-ethylene glycol or terephthalic acid-bis-1, 4-butanediol, hydroxyalkylene ethers of hydroquinone or resorcinol, for example 1, 4-bis (. beta. -hydroxyethyl) hydroquinone or 1, 3- (. beta. -hydroxyethyl) resorcinol, alkanolamines of 2 to 12 carbon atoms, for example ethanolamine, 2-aminopropanol and 3-amino-2, 2-dimethylpropanol, N-alkyldialkanolamines, for example N-methyl and N-ethyldiethanolamine, (cyclo) aliphatic diamines of 2 to 15 carbon atoms, such as 1, 2-ethylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine and 1, 6-hexamethylenediamine, isophoronediamine, 1, 4-cyclohexylenediamine and 4, 4 '-diaminodicyclohexylmethane, N-alkyl-substituted, N' -dialkyl-substituted aromatic diamines, which may also be substituted on their aromatic groups by alkyl groups having 1 to 20, preferably 1 to 4, carbon atoms in the N-alkyl groups, for example N, n ' -diethyl, N ' -di-sec-pentyl, N ' -di-sec-hexyl, N ' -di-sec-decyl and N, N ' -dicyclohexyl (p-or m-) phenylenediamine, N ' -dimethyl, N ' -diethyl, N ' -diisopropyl, N ' -di-sec-butyl, N ' -dicyclohexyl, -4, 4 ' -diaminodiphenylmethane, N ' -di-sec-butylbenzidine, bis (4-amino-3-methylbenzoic acid) methylene ester, 2, 4-chloro-4, 4 ' -diaminodiphenylmethane, 2, 4-and 2, 6-toluenediamine.

The compounds of component e) can be used in mixtures or individually. Mixtures of chain extenders and crosslinkers may also be used.

To adjust the hardness of the PU elastomers, the structural components b), c), d) and e) can be varied within a relatively wide range of ratios, the hardness increasing with increasing content of component e) in the reaction mixture.

The amounts of structural components b), c), d) and e) required to achieve the desired hardness in the PU elastomers can be determined easily by experiment. Advantageously, the amount used is from 1 to 50 parts by weight, preferably from 2.5 to 20 parts by weight, of chain extenders and/or crosslinkers e), relative to 100 parts by weight of higher molecular weight compounds b), c) and d).

Amine catalysts familiar to the person skilled in the art can be used as component f), for example tertiary amines, such as triethylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, N, N, N ', N ' -tetramethylethylenediamine, pentamethyldiethylenetriamine and the higher homologues (DE-A2624527 and DE-A2624528), 1, 4-diazabicyclo- [2, 2, 2] -octane, N-methyl-N ' -dimethylaminoethylpiperazine, bis (dimethylaminoalkyl) piperazine, N, N-dimethylbenzylamine, N, N-dimethylcyclohexylamine, N, N-diethylbenzylamine, bis (N, N-diethylaminoethyl) adipate, N, N, N ', N ' -tetramethyl-1, 3-butanediamine, N, n-dimethyl- β -phenylethylamine, bis (dimethylaminopropyl) urea, bis (dimethylaminopropyl) amine, 1, 2-dimethylimidazole, 2-methylimidazole, monocyclic and bicyclic amidines, bis (dialkylamino) alkyl ethers, for example bis (dimethylaminoethyl) ether and tertiary amines having an amido group, preferably a carboxamide group (according to DE-A2523633 and DE-A2732292). Examples of further catalysts include the mannich bases known per se from secondary amines, such as dimethylamine, with aldehydes, preferably formaldehyde, or ketones, such as acetone, butanone or cyclohexanone, and phenols, such as phenol, nonylphenol or bisphenol. Catalysts in the form of tertiary amines having hydrogen atoms which are active with respect to isocyanate groups are, for example, triethanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-dimethylethanolamine, their reaction products with alkylene oxides such as propylene oxide and/or ethylene oxide and secondary-tertiary amines according to DE-A2732292. Silamines having carbon-silicon bonds (Silamines), such as those described in U.S. Pat. No. 3, 3620984, can also be used as catalysts, for example 2, 2, 4-trimethyl-2-silamorpholine and 1, 3-diethylaminomethyl tetramethyldisiloxane. Other examples include nitrogenous bases, such as tetraalkylammonium hydroxides, and also hexahydrotriazines. The reaction between NCO groups and Zerewitinoff-active hydrogen atoms is also accelerated considerably by lactams and azalactams.

At least one lithium salt h) of an organic carboxylic acid with at least one organic compound g) of titanium and/or zirconium is preferably used as catalyst. If desired, the catalyst combination can be extended to include at least one bismuth compound i) as a third component. The catalysts can be added to the polyol preparation in the form of a prepared mixture or separately in corresponding proportions. Preferably separately.

Saturated or unsaturated, aliphatic or alicyclic and aromatic carboxylates of lithium, which are familiar to the person skilled in the art, are particularly preferably used as component h). They correspond to the following general formula:

[Li(OOCR)]

[Li₂((OOC)₂R)]

wherein R is a hydrocarbyl group of 1 to 25 carbon atoms. Preferred catalysts are, for example, branched alkanoates, resinates, oxalates, adipates and stearates of lithium (I). Particularly preferred catalysts are the naphthenates, decanoates, butyrates, isobutyrates, nonanoates, benzoates and caprinates of lithium (I). The neodecanoates, -2-ethylhexanoates and octanoates of lithium (I) are also particularly preferred.

Component h) can also be used as a solution of lithium hydroxide or lithium carbonate, or as a solution of a mixture of these salts in one or more of the carboxylic acids characterized in the preceding paragraph.

Organic compounds of titanium and/or zirconium familiar to the person skilled in the art can be used as component g). They preferably correspond to the following general formula:

[M(L¹)(L²)(L³)(L⁴)]_n

[M(L¹)(L²)(L³)]_n

[M(L¹)(L²)]_n

[M(L¹)]_n

wherein M represents titanium or zirconium, n can assume a value between 1 and 20, L¹、L²、L³And L⁴Ligands which may be identical or different, are the following groups coordinated through O, S or the N atom:

(1) alkoxide, phenoxide, glycolate, thiolate, carboxylate, or aminoalkoxide containing from 1 to 20 carbon atoms and optionally one or more functional groups (e.g., hydroxyl, amino, carbonyl, etc.) or having a bond containing oxygen, sulfur, or nitrogen (e.g., in the form of an ether, thioether, amine, or carbonyl)

(2) Various fluorine-free sterically unhindered chelating ligands selected from the group consisting of 1-diketones, such as benzoylacetone, dibenzoylmethane, ethyl benzoylacetate, methyl acetoacetate, ethyl acetoacetate, and 2, 4-pentanedione (also known as acetylacetone), as well as other chelating ligands, such as N, N-dimethylethanolamine, triethanolamine, salicylaldehyde, salicylamide, phenyl salicylate, cyclopentanone-2-carboxylic acid, diacetyl acetylacetone, thioacetylacetone, N, N' -bis (salicylidene) ethylenediamine, glycolic acid, ethylene glycol, and the like.

Preferred components g) are, for example, titanium (IV) isopropoxide, titanium (IV) n-butoxide, titanium (IV) 2-ethylhexanoate, titanium (IV) n-pentanolate, titanium (IV) isopropoxide triethanolamine, titanium (IV) n-butoxide triethanolaminated, isopropyl triisostearyl titanate, titanium (IV) bis (8-quinolinolato) dibutanolate, titanium (IV) bis (ethylacetoacetonate) diisobutyl alcoholate, bis (ethylacetylacetonate) titanium (IV) diisopropoxide, zirconium (IV) isopropoxide, zirconium (IV) n-butoxide, zirconium (IV) 2-ethylhexanoate, zirconium (IV) n-pentanolate, zirconium (IV) isopropoxide (triethanolaminated), zirconium (IV) n-butoxide, isopropyl-triisostearyl zirconate, bis (8-quinazolinol) zirconium (IV) dibutanolate, and bis (ethylacetylacetonate) zirconium (IV) diisobutylate.

Particularly preferred titanium compounds with ligands are, for example, those listed in paragraph (2) above. Among these titanium compounds, diisopropoxide-bis (2, 4-pentanedionato) titanium (IV), triisopropanolate (2, 4-pentanedionato) titanium (IV), ethoxybis (penta-2, 4-diketonato-O, O') (propan-2-olate (olato)) titanium, acetylacetonato titanium (IV), bis (diacetoneacetonato) titanium (IV) butanolate, isopropanolate and bis (diacetoneacetonato) titanium (IV) ethanolate, isopropanolate are preferably used.

Many of the catalysts listed under g) can form agglomerates and/or higher molecular weight condensation products having two or more metal sites connected to each other by one or more bridging ligands. For this reason, n may vary from 1 to about 20. Compounds having n between 1 and 10 are preferred.

Component i) comprises saturated and/or unsaturated, aliphatic or alicyclic and aromatic bismuth carboxylates. They preferably correspond to the following general formula:

[Bi(OOCR)₃]

[Bi₂((OOC)₂R)₃]

wherein R is a hydrocarbyl group of 1 to 25 carbon atoms.

Preferred carboxylates are branched alkanoates, resinates, stearates, adipates and oxalates of bismuth (III). Preference is also given to the naphthenates, decanoates, butyrates, isobutyrates, nonanoates and caprinoates of bismuth (III). The neodecanoates, -2-ethylhexanoates and octanoates of bismuth (III) are also particularly preferred.

The components g, h) and/or i) are preferably used as liquid formulations with one or more solvents. Saturated and/or unsaturated, aliphatic or alicyclic and aromatic carboxylic acids having the general formula:

RCOOH

HOOC-R-COOH

particularly useful as solvents, where R is a hydrocarbyl group of 1 to 25 carbon atoms.

For example, neodecanoic acid, 2-ethylhexanoic acid and cyclohexanoic acid are preferably used.

Instead of the carboxylic acids mentioned above, the following solvents can also be used:

● aliphatic and aromatic liquids, such as Stoddard solvent, naphtha, white spirit, xylene, hexane, heptane, toluene, and paraffinic mineral oil,

● esters, for example, ethyl acetate and isopropyl acetate,

● alcohols, for example ethanol, n-propanol, isopropanol, n-butanol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethanol, diethylene glycol, triethylene glycol, diethylene glycol monoethyl ether, ethylene glycol,

● ketones, such as butanone, acetone and,

● ethers, e.g. diethylene glycol butyl ether and

● in special cases, water can also be used.

The catalyst combinations composed of g) and h) or g), h) and i) are generally used in amounts of about 0.001 to 10% by weight, preferably 0.01 to 0.5% by weight, relative to the sum of the compounds b) to k).

The catalyst combination consisting of components g) and h) being based on the mass n of the titanium ions in component g)_TiAnd/or the mass n of zirconium ions_ZrWith the amount of substance n of the lithium ions in component h)_LiThe ratios of the two components are in the range of 0.2 to 4, preferably 0.43 to 1.5. Such asIf a component i) is additionally used, the component i) is used in such a way that the mass n of the bismuth ions in the component i) is equal to_BiUse of: mass n of bismuth ions in component i)_BiWith mass n of substance_TiAnd/or n_ZrAnd n_LiThe ratio of the sum of the amounts is 0.0001 to 0.53, preferably 0.0001 to 0.24, particularly preferably 0.0001 to 0.15.

Compact PU elastomers, such as PU shoe outsoles, can be produced in the absence of moisture and physically or chemically acting blowing agents.

In the production of microcellular PU elastomers, water is preferably used as blowing agent j), which reacts in situ with organic diisocyanates and/or polyisocyanates or with prepolymers a) having isocyanate groups to form carbon dioxide and amino groups, which in turn react further with other isocyanate groups to form urea groups and thus act as chain extenders.

If water is added to the polyurethane formulation in order to establish the desired density, it will be used conventionally in an amount of from 0.001 to 3.0% by weight, preferably from 0.01 to 2.0% by weight, in particular from 0.05 to 0.7% by weight, relative to the weight of components a), b) and optionally c), d) and e).

As blowing agent j), gases or highly volatile inorganic or organic substances which evaporate under the influence of the exothermic addition polymerization and preferably have an atmospheric boiling point of from-40 to 120 ℃ and preferably from-30 to 90 ℃ can also be used as physical blowing agents instead of or preferably together with water. Examples include, for example, acetone, ethyl acetate, haloalkanes or perfluorinated alkanes, for example, (R134a, R141b, R365mfc, R245fa), also butane, pentane, cyclopentane, hexane, cyclohexane, heptane or diethyl ether as organic blowing agents, and, for example, air, carbon dioxide or N₂O as an inorganic blowing agent. Foaming can also be achieved by adding compounds which decompose at temperatures above room temperature with evolution of gases, for example nitrogen and/or carbon dioxide, for example azo compounds, such as azodicarbonamide (azoisobutyronitrile), or salts, such as ammonium bicarbonate, ammonium carbamate, or ammonium salts of organic carboxylic acidsFor example, the mono-ammonium salt of malonic acid, boric acid, formic acid or acetic acid. Further examples of blowing agents and details of their use are described in r.vieweg, a.h * chtlen (main edition): a Plastic handbook, volume VII, Carl-Hanser Press, Munich, 3 rd edition, 1993, p.115 to 118, 710 to 715.

Solid blowing agents, low-boiling liquids or gases which are expediently used and may be used in each case individually or in mixtures, for example as liquids or gas mixtures or as gas-liquid mixtures, in amounts which depend on the desired density and the amount of water used. The amount required is readily determined by experimentation. Satisfactory results are generally in the range of 0.5 to 35% by weight, preferably 2 to 15% by weight solids; 0.5 to 30 wt%, preferably 0.8 to 18 wt% of liquid; and/or from 0.01 to 80% by weight, preferably from 10 to 50% by weight, of a gas, in each case relative to the weight of components a), b), c), d) and e). The introduction of gases, for example air, carbon dioxide, nitrogen and/or helium, can be effected both by the higher molecular weight polyhydroxyl compounds b), c) and d), by the low molecular weight chain extenders and/or crosslinkers e), and also by the polyisocyanates a) or by a) and b) and optionally c), d) and e).

Additives k) may optionally be added to the reaction mixture to produce compact or microcellular PU elastomers. Examples which may be mentioned include surface-active additives, such as emulsifiers, foam stabilizers, cell regulators, flame retardants, nucleating agents, oxidation retarders, stabilizers, lubricants and mold release agents, dyes, dispersants and pigments. Examples of emulsifiers include, for example, the sodium salt of castor oil sulfonate or the salts of fatty acids with amines, for example, oleic acid diethylamine or stearic acid diethanolamine. Alkali metal or ammonium salts of sulfonic acids, for example dodecylbenzenesulfonic acid or dinaphthylmethanedisulfonic acid, or of fatty acids, for example ricinoleic acid or poly fatty acids, may additionally be used in combination as surface-active additives. Examples of foam stabilizers include all of the above polyether siloxanes, especially the water-soluble examples. These compounds are generally synthesized to have a structure composed of a copolymer of ethylene oxide and propylene oxide bonded to a polydimethylsiloxane group. Such foam stabilizers are disclosed, for example, in US-A2834748, US-A2917480 and US-A3629308. Of particular interest are polysiloxane-polyoxyalkylene copolymers which are polybranched by means of allophanate groups according to DE-A2558523. Also suitable are other organic polyisocyanates, ethoxylated alkylphenols, ethoxylated fatty alcohols, paraffin oils, castor oil or ricinoleic acid esters, sulfated castor oil, peanut oil, and cell regulators such as paraffins, fatty alcohols and polydimethylsiloxanes. Oligomeric polyacrylates having polyalkylene oxide and fluoroalkyl groups as side groups are also suitable for improving the emulsifying effect, the dispersion of fillers, the cell structure and/or the stabilization. The surface-active substances are conventionally used in amounts of 0.01 to 5 parts by weight, based on 100 parts by weight of the higher molecular weight polyhydroxyl compounds b) and c). Reaction retarders known per se, also pigments or dyes and flame retardants, also stabilizers with an anti-ageing or anti-weathering effect, plasticizers and substances with an antifungal and antibacterial activity may also be added.

Further examples of surface-active additives and foam stabilizers and cell regulators, reaction retarders, stabilizers, flame retardant substances, plasticizers, dyes and fillers and substances with antifungal and bacterial activity which may optionally additionally be used together, and details of the use and mode of action of these additives, are described in r.vieweg, a.h * chtlen (main eds): a plastics handbook, volume VII, Carl-Hanser Press, Munich, 3 rd edition, 1993, p.118 to 124.

For the preparation of the PU elastomers according to the invention, the components are reacted in amounts such that the equivalent ratio of NCO groups in isocyanate a) to the sum of the isocyanate group-active hydrogens in components b), c), d) and e) and any chemically acting blowing agents j) which may be used is from 0.8: 1 to 1.2: 1, preferably from 0.95: 1 to 1.15: 1, in particular from 1.00: 1 to 1.05: 1.

The PU elastomers of the invention can be prepared by processes described in the literature, for example, the one-shot or prepolymer process, using mixing apparatuses which are known in principle to those skilled in the art. The prepolymer process is preferably used to produce such elastomers.

In one embodiment of the production of the PU elastomers according to the invention, the starting components are mixed homogeneously without blowing agent j), conveniently at a temperature of from 20 to 80 ℃ and preferably from 25 to 60 ℃, and the reaction mixture is introduced into an open, optionally temperature-controlled mold and cured. In a further embodiment of the PU elastomer production according to the invention, the structural components are mixed in the same manner but in the presence of a blowing agent j), preferably water, and then introduced into an optionally temperature-controlled mold. After the filling, the mould is closed and the reaction mixture is foamed, wherein an excess filling (packing) is used, for example an excess filling degree (ratio of moulding density to free rise density) of 1.05 to 8, preferably 1.1 to 6, in particular 1.2 to 4, to produce the moulded part. The mouldings are demoulded as soon as they have sufficient strength. The demolding time is conveniently between 1.5 and 15min, depending on, inter alia, the mold temperature and shape and the reactivity of the reaction mixture.

The PU elastomer of the invention conveniently has a viscosity of 180 to 1100kg/cm³The density of (c) depends mainly on the material and the type of filler. They are used, for example, in densities of from 400 to 650kg/m³In a molded outsole or one-component direct outsole film system; used in a density of 500-700 kg/m³In the boot system of (1); for a density of 800-1100 kg/m³The two layers of soles are tightly pressed to form a tight outsole or a direct outsole film system; the density of the middle sole or direct outsole film system formed by two layers of soles is 400-500 kg/m³(ii) a And a density of 180 to 400kg/m³In the insole of the shoe.

The PU elastomer of the invention is a particularly valuable raw material for manufacturing soles with single-layer or multi-layer structures.

The present invention will be illustrated in more detail by the following examples.

Examples

Preparation of polyurethane samples: component A (Table 1), 30 ℃ was mixed with component B (Table 2), 30 ℃ in a low-pressure foaming apparatus (ND1), the mixture was poured into aluminum folding moulds (dimensions 200X 140X 10mm) heated to 50 ℃, the folding moulds were closed and the elastomer was released after 3 min.

From the elastomer sheets thus prepared, the Shore A hardness (DIN 53505) was determined immediately after demolding and after storage for 24h, respectively. The puncture expansion (DIN 53522) was also determined after 60,000 bending cycles for a 2mm wide puncture (dimensions 2 cm. times.15 cm. times.lcm) along the sample bending line. The results are shown in tables 4 to 8.

Examples 1 to 5

Polyurethane elastomers were prepared by reacting 100 parts of the polyol formulation (a component, see table 1) and 61 parts of the prepolymer (B component, see table 2). Each example, along with its physical and chemical properties, is set forth in tables 4-8. The chemical names corresponding to the trade names of the catalysts and other components listed in the table are given in table 3. In addition to the catalyst combinations of the present invention, experiments were also conducted using metal compounds and mixtures not in accordance with the present invention for comparison.

Table 1: polyol formulation (A component)

% by weight	Component A
		The balance being added to 100	Polyether diol b) (weight ratio PO: EO 70: 30; molecular weight 4000g/mol)
10	Polyether triol c) (weight ratio PO: EO 78: 22; molecular weight 6000g/mol)
		10	Butanediol e)
0.2	TELA e)
		0.5	DABCO f)
Y	Catalysts and amounts thereof (see Table 4)
		0.10	DC-190k)
0.35	Water j)

Table 2: prepolymer formulation (B component)

% by weight	B component
		66	4，4’-MDI a)
5	Polymeric MDI (29.8 wt% NCO, functionality 2.1) a)
		29	A mixture of tripropylene glycol and PO polyether; number average molecular weight 690 g/mol; functionality 2b)

Table 3: trade name/abbreviation interpretation

Trade name or abbreviation	Chemical name
		Tyzor*AA 95 from DuPont	Bis (diacetoneacetonato) titanium (IV) butanolate Isopropanolate in Butanol
Tyzor*AA 105 from DuPont	Bis (diacetoneacetonato) titanium (IV) ethanolate Isopropanolate
		Li2 Hex-Cem*From OMG (Ontokumpononey group)	Lithium 2-ethylhexanoate in 2- (2-ethoxyethoxy) ethanol
Li Ten-Cem*water sol from OMG	Lithium neodecanoate aqueous solution
		DBTL	Dibutyl tin dilaurate
Coscat*83 from D.H.Erbsl * h	Bismuth (III) neodecanoate
		TELA	Triethanolamine
DABCO	Diamino bicyclo octane
		DC-190*From Air Products	Foam stabilizer

Tables 4-8 show the results of tests on polycarbonate elastomers prepared using various catalysts. The concentration of the catalyst is given in wt% relative to the a component. The quantitative ratios of the substances [ nTi: nLi ] and [ (nTi + nLi): nBi ] are also given.

TABLE 4: use of tin catalysts (prior art)

Experiment of	Tin catalyst		Milk white period (sec)]	Fiber stage [ sec ]]	Shore-A hardness, x min determination after demolding				Shore-A hardness, 24h after demoulding	Puncture and expansion, mm, b is 60,000 times of bending
											Name (R)	In an amount wt. -%)	After 0min	After 2min	After 10min	After 60min
	1	DBTL			0.02	11	22	37									42	47	51	54	35000*/30000*35000*/30000*
2			DBTL	0.03					10	15	34	38	44	48	52	6.7/60000*

All values in the band indicate the number of bends b after which the test strip failed.

Table 5:use of titanium, lithium and bismuth catalysts with various ligands

Experiment of	Lithium component		Titanium component		Bismuth component		[nTi∶nLi]	nBi∶(nTi+nLi)	Milk white period (sec)]	Fiber stage [ sec ]]	Shore-A hardness, x degree of separation after demolding				Shore-A hardness, 24h after demoulding	Puncture and expansion, mm, b is 60,000 times of bending
																	Name (R)	In an amount wt. -%)	Name (name)Balance	In an amount wt. -%)	Name (R)	In an amount wt. -%)	After 0min	After 2min	After 10min	After 60min
	3			TyzorAA105	0.15									11													17	30	35	45	54	56	4.1/3.2
4							Li-2-HexCem	0.06	TyzorAA105	0.09							1.38		11	24	33	38	46	52	54	2.9/2.2
	5	Li TenCem	0.15											11													33	25	30	39	43	48	4.3/6.2
6							Li TenCem	0.1	TyzorAA95	0.1							0.25		11	20	38	42	49	52	54	1.8/3.6
	7	OctaSoligenLithium	0.1	TyzorAA95	0.1							0.85		12													27	45	40	48	52	52	1.8/2.9
8							Lithium stearate	0.03	TyzorAA95	0.04					Coscat 83	0.02	1.83	0.7	9	22	31	35	45	50	54	2.4/1.2
	9	Lithium benzoate	0.0014	TyzorAA95	0.04	Coscat 83					0.02	1.83	0.7	9													24	32	36	46	51	53	60000*/55000*
10							Li-2-HexCem	0.04	TyzorAA95	0.04					72% solution of bis-2-ethylhexanoate in a solvent oil	0.014	0.92	0.07	11	26	33	39	47	51	53	2.1/1.8
	11	Li-2-HexCem	0.04	TyzorAA95	0.04	72% solution of bis-2-ethylhexanoate in xylene					0.014	0.92	0.07	11													22	33	41	46	50	53	3.3/1.9

All values in the band indicate the number of bends b after which the test strip failed.

Table 6:use of various amounts of titanium and lithium catalysts

Experiment of	Lithium component		Titanium component		[nTi∶nLi]	Milk white period (sec)]	Fiber stage [ sec ]]	Shore-A hardness, x degree of separation after demolding				Shore-A hardness, 24h after demoulding	Puncture and expansion, mm, b is 60,000 times of bending
														Name (R)	In an amount wt. -%)	Name (R)	In an amount wt. -%)	After 0min	After 2min	After 10min	After 60min
	12	Li-2-HexCem	0.15							15	44											29	34	43	51	52	45000*/4.3
13					Li-2-HexCem	0.12	Tyzor AA 95					0.03	0.23	12	32	35	39	48	53	54	2.5/7.6
	14	Li-2-HexCem	0.09	Tyzor AA 95				0.06	0.61	12	23											38	41	50	55	55	2.8/4.5
15					Li-2-HexCem	0.075	Tyzor AA 95					0.075	0.92	11	23	38	42	51	55	56	4.1/4.2
	16	Li-2-HexCem	0.06	Tyzor AA 95				0.09	1.38	11	21											36	41	50	54	55	3.5/4
17					Li-2-HexCem	0.03	Tyzor AA 95					0.12	3.67	10	20	35	41	50	53	55	4.1/4.5
	18			Tyzor AA 95				0.15		11	18											34	39	49	53	56	12.6/6.7

All values in the band indicate the number of bends b after which the test strip failed.

Table 7:titanium and lithium catalysts in various amounts, and use of bismuth catalysts

Experiment of	Lithium component		Titanium component		Bismuth component		[nTi∶nLi]	nBi∶(nTi+nLi)	Milk white period (sec)]	Fiber stage [ sec ]]	Shore-A hardness, x degree of separation after demolding				Shore-A hardness, 24h after demoulding	Puncture and expansion, mm, b is 60,000 times of bending
																	Name (R)	In an amount wt. -%)	Name (R)	In an amount wt. -%)	Name (R)	In an amount wt. -%)	After 0min	After 2min	After 10min	After 60min
	19	Li-2-HexCem	0	TyzorAA 95	0.1	Coscat 83					0.02		0.27	11													20	30	35	42	48	53	60000*/11.9
20							Li-2-HexCem	0.02	TyzorAA 95	0.06					Coscat 83	0.02	2.75	0.27	9	20	35	40	47	52	55	60000*/1.31
	21	Li-2-HexCem	0.04	TyzorAA 95	0.04	Coscat 83					0.02	0.92	0.26	10													24	35	40	46	50	53	7.7/6.2
22							Li-2-HexCem	0.06	TyzorAA 95	0.02					Coscat 83	0.02	0.31	0.26	11	26	34	39	45	47	52	60000*/6.2
	23	Li-2-HexCem	0.08	TyzorAA 95	0	Coscat 83					0.02		0.25	11													39	31	36	46	51	52	4.5/4.0

All values in the band indicate the number of bends b after which the test strip failed.

Table 8:application of various titanium, lithium and bismuth catalysts with different dosages

Experiment of	Lithium component		Titanium component		Bismuth component		[nTi∶nLi]	nBi∶(nTi+nLi)	Milk white period (sec)]	Fiber stage [ sec ]]	Shao pinHardness of the alloy in the molar ratio of-A, x-component after demoulding				Shore-A hardness, 24h after demoulding	Puncture and expansion, mm, b is 60,000 times of bending
																	Name (R)	In an amount wt. -%)	Name (R)	In an amount wt. -%)	Name (R)	In an amount wt. -%)	After 0min	After 2min	After 10min	After 60min
	24#					Coscat 83					0.1		0	10													35	28	35	47	50	55	1.6/1.7
25							Li-2-HexCem	0.04	TyzorAA 95	0.04					Coscat 83	0.02	0.92	0.07	10	24	35	40	46	50	53	7.7/6.2
	26#	Li-2-HexCem	0.026	TyzorAA 95	0.026	Coscat 83					0.046	0.92	0.25	8													23	37	43	50	53	57	3.3/4.4
27							Li-2-HexCem	0.036	TyzorAA 95	0.036					Coscat 83	0.028	0.92	0.11	8	22	37	42	50	54	56	4.6/3.2
	28	Li-2-HexCem	0.042	TyzorAA 95	0.042	Coscat 83					0.015	0.92	0.05	10													28	34	39	46	50	56	9.2/4.0
29							Li-2-HexCem	0.046	TyzorAA 95	0.046					Coscat 83	0.008	0.92	0.03	9	25	35	40	49	51	57	60000*/13.6
	30	Li-2-HexCem	0.05	TyzorAA 95	0.05							0.92		10													22	33	38	47	50	53	3.4/3.6

Repeated flexing test results for all bands showed failure after b bends

All elastomeric sheets with # in the test were dimensionally unstable after demolding. The sheet is wrinkled.

Claims (13)

1. A polyurethane elastomer obtainable by reacting the following components a) to e) in the presence of f) to k):

a) organic di-and/or polyisocyanates with

b) At least one polyether polyol having a number average molecular weight of 800 to 25,000g/mol and an average functionality of 1.6 to 2.4,

c) optionally, a polyether polyol other than b) having a number average molecular weight of 800 to 25,000g/mol and an average functionality of 2.4 to 8,

d) optionally, a polymer polyol containing from 1 to 50% by weight of filler, and having a hydroxyl number of from 10 to 149 and an average functionality of from 1.8 to 8, relative to the polymer polyol,

e) optionally, a low molecular weight chain extender having an average functionality of 1.8 to 2.1, a molecular weight of 750g/mol or less, and/or a crosslinker having an average functionality of 3 to 4, and a molecular weight of up to 750g/mol,

f) an amine catalyst and a catalyst mixture consisting of,

g) at least one organic titanium and/or zirconium compound,

h) and at least one lithium salt of an organic carboxylic acid,

i) and optionally additionally at least one bismuth salt of an organic carboxylic acid,

j) optionally a blowing agent and

k) optionally an additive(s) is (are),

wherein the amount of substance n of titanium ions in component g)_TiAnd/or the mass n of zirconium ions_ZrWith the amount of substance n of the lithium ions in component h)_LiThe ratio of the bismuth ions to the bismuth ions is 0.2 to 4, and the amount of substance n of the bismuth ions in the component i)_BiWith mass n of substance_TiAnd/or n_ZrAnd n_LiThe ratio of the sum of the amounts is 0.0001 to 0.53.

2. A polyurethane elastomer according to claim 1 characterised in that in component (d) optionally the polymer polyol contains 1 to 45% by weight of filler relative to the polymer polyol.

3. A polyurethane elastomer according to claim 1 characterised in, that the catalyst mixture is used in an amount of 0.001 to 10 wt% relative to the total amount of components b) to k).

4. A polyurethane elastomer according to claim 3 characterised in, that the catalyst mixture is used in an amount of 0.01 to 0.4 wt% relative to the total amount of components b) to k).

5. A polyurethane elastomer as claimed in any one of claims 1 to 4 characterised in that components g), h) and i) are used as catalyst mixtures.

6. A polyurethane elastomer as claimed in any one of claims 1 to 4 characterised in that components g) and h) are used as catalyst mixtures.

7. A polyurethane elastomer as claimed in any one of claims 1 to 4, characterised in that as component a) a prepolymer is used consisting of: i)4, 4 '-diphenylmethane diisocyanate and/or 4, 4' -diphenylmethane diisocyanate modified by a carbodiimidization reaction and ii) one or more polyether polyols having a hydroxyl number of from 10 to 112, optionally mixed with polyethylene glycol or polypropylene glycol having a molecular weight of from 135g/mol to 700 g/mol.

8. A process for the preparation of a polyurethane elastomer as claimed in any one of claims 1 to 7, characterised in that components a) to e) are reacted in the presence of f) to k):

a) organic di-and/or polyisocyanates with

b) At least one polyether polyol having a number average molecular weight of 800 to 25,000g/mol and an average functionality of 1.6 to 2.4,

c) optionally, a polyether polyol other than b) having a number average molecular weight of 800 to 25,000g/mol and an average functionality of 2.4 to 8,

d) optionally, a polymer polyol containing from 1 to 50% by weight of filler, and having a hydroxyl number of from 10 to 149 and an average functionality of from 1.8 to 8, relative to the polymer polyol,

e) optionally, a low molecular weight chain extender having an average functionality of 1.8 to 2.1, a molecular weight of 750g/mol or less, and/or a crosslinker having an average functionality of 3 to 4, and a molecular weight of up to 750g/mol,

f) an amine catalyst and a catalyst mixture consisting of,

g) at least one organic titanium and/or zirconium compound,

h) and at least one lithium salt of an organic carboxylic acid,

i) and optionally additionally at least one bismuth salt of an organic carboxylic acid,

j) optionally a blowing agent and

k) optionally an additive(s) is (are),

wherein the amount of substance n of titanium ions in component g)_TiAnd/or the mass n of zirconium ions_ZrWith the amount of substance n of the lithium ions in component h)_LiThe ratio of the bismuth ions to the bismuth ions is 0.2 to 4, and the amount of substance n of the bismuth ions in the component i)_BiWith mass n of substance_TiAnd/or n_ZrAnd n_LiThe ratio of the sum of the amounts is 0.0001 to 0.53.

9. The process of claim 8, wherein in component (d), optionally, the polymer polyol contains from 1 to 45% by weight of filler relative to the polymer polyol.

10. Use of a polyurethane elastomer according to any one of claims 1 to 7 for the manufacture of elastomeric mouldings.

11. The use according to claim 10, wherein the elastomeric molding has a density of from 180 to 1100kg/m³The sole of (1).

12. An elastomer molded article for industrial and consumer goods, which is produced from the polyurethane elastomer according to any one of claims 1 to 7.

13. The elastomeric molding for industrial and consumer goods according to claim 12, wherein said elastomeric molding is a shoe sole.