HK1086290B - Polyurethane elastomers, method for the production thereof and use of the same - Google Patents

Description

Polyurethane elastomer, method for the production thereof and use thereof

The invention relates to polyurethane elastomers having a defined node density, to a method for the production thereof using specific polyetherester polyols and to the use thereof, in particular for the production of microcellular and solid polyurethane elastomer components.

Various methods for producing polyurethanes, which contain polyether groups and polyester groups in the so-called soft segments, have been described in the past in parallel.

A variant (Pluminska-Michalak, B.; Lisoska, R.; Balas, A. "Journal of Elastomers and Plastics (Journal of Elastomers and Plastics) (26) 1994327-334) consists in the reaction of a polyether-based NCO prepolymer with a polyester polyol. The friction is reduced in the resulting polyurethane elastomer, the long-term flexural strength at room temperature and-15 ℃ is improved, and the viscosity of the NCO prepolymer is reduced compared to polyester-based NCO prepolymers. However, it is disadvantageous that mixing the components becomes more difficult without problems due to the large difference in viscosity between the reaction components. A further disadvantage is the inherent risk of microphase separation in the so-called polyurethane elastomer soft segment, which impairs the properties of the finished product.

Another alternative (DE-A19927188) proposes physically mixing polyethers and polyesters in polyol formulations. In this way, polyurethanes with improved oil resistance compared to polyether polyurethanes can be obtained. An insufficient shelf life of the polyol formulation is disadvantageous, since the low compatibility of polyester and polyether leads to macroscopic demixing after a relatively short time. Users of such systems experience undesirable difficulties with respect to storage and logistics.

The above-mentioned disadvantages are prevented by the use of separation-stable polyetherester polyols, which can be prepared by a discontinuous synthesis: in the polyether block, the polyester is alkoxylated with alkylene oxide, polycondensed with alkylene oxide, two-stage and one-stage polycondensed.

However, it has in fact been the case that such polyetherester polyols do not provide PUs having generally good flexural strength, in particular if they have been exposed to hydrolytic ageing.

In U.S. Pat. No. 3, 5436314 (built-in polyether) carboxylic acids or carboxylic acid anhydrides are reacted with polyether polyols in the presence of strong Bronsted acids and polyetherester polyols having randomly distributed ester groups are obtained. However, these products do not have polymethylene segments of varying lengths, although they contribute substantially to the good properties of many polyesters. Metal salts of strong bronsted acids further impair polyetheresters and reduce the hydrolytic stability of their ester bonds, so that their use in, for example, shoe soles results in poor materials.

When alkoxylating a polyester with an alkylene oxide, the polyester is first prepared, after which it is alkoxylated with an alkylene oxide. This is a widely spread process which results in a 3-block copolymer, a polyester-block-polyether polyol. The inherent disadvantage of this process is that the block structure of the polyether-block-polyester polyols created in this complex manner cannot be in transesterification equilibrium. For this reason, they may rearrange at elevated temperatures and lose their constituent structure. This has an undesirable effect on their storage life.

In DE-A19858104 polyester carboxylic acids are synthesized from cyclic esters, alcohols and carboxylic acids in a first stage and are alkoxylated with ethylene oxide or propylene oxide in a subsequent step, preferably without addition of a catalyst. The product is used as a raw material of rigid foam. Here, they reduce shrinkage, increase strength and reduce the tendency to crystallize. However, these advantages can only be achieved if at least one polyol component or one isocyanate has a number average functionality of significantly more than 2, which enables the construction of highly crosslinked polyurethane systems. Microcellular elastomers having good properties, for example good long-term flexural strength, cannot be obtained in this way, as is generally known in the art. Without increasing expenditure, it is not possible to prepare further cyclic esters from which the polyester polyols of the first synthesis step are synthesized, since they first have to be obtained from a mixture of linear and cyclic esters by extraction or distillation, which has the major disadvantage.

In US-a 4487853 the acid half-esters are prepared as intermediates by esterification of polyether polyols with carboxylic acid anhydrides, followed by amine or tin compounds to provide a catalyzed ethoxylation, resulting in polyester-co-polyether polyols which are low in ester groups and have a high proportion of terminal primary hydroxyl groups. However, the use of ether groups in high excess to the base of the ester is disadvantageous, so that the advantages of typical polyetherester polyols or polyester-block-polyether polyols are not fully realized. Dicarboxylic acid anhydrides, which are generally expensive, must be further used as raw materials for the synthesis of adipates, which constitute important raw materials for polyurethane elastomers.

Double metal cyanide catalysts are used in WO 200127185. They enable the ether blocks to start on the polyesterols with small amounts of by-products and unsaturated end groups. The product has good compatibility with ethers and esters, which are recommended as surfactants or phase promoters. However, the disadvantage arises that polyethers having a large number of terminal primary hydroxyl groups are known not to be preparable with double metal cyanide catalysts, since the ethylene oxide polymerization starts on a small number of hydroxyl functions when it builds up high molecular weight polyethylene oxide units. For this reason the polyester-block-polyether polyols provided in WO 200127185 have only limited use in polyol formulations, especially when the polyols have a majority of secondary hydroxyl groups of low reactivity. This limitation is a major drawback for many applications.

In DE-A2110278 (polycondensation with alkylene oxide), polyether polyols, carboxylic anhydrides and alkylene oxides are reacted in a one-pot process to give polyetherester polyols having randomly distributed polyether units. Because of the nature of the process the alkylene oxide forms only derivatized dimethylene bridges. Longer carbon bridges such as those used in butanediol or hexanediol esters are lacking. Expensive adipic anhydride must also be used in the process.

In DE-A3437915 (two-stage polycondensation) the reaction of polyether alcohols with carboxylic acids or carboxylic acid anhydrides or carboxylic acid esters produces polyester carboxylic acids which are reacted in a second stage with aliphatic alcohols to give the actual polyether ester polyols. The disadvantage in this case is, on the one hand, the multistage process and, on the other hand, the expensive carboxylic acid derivatives. A similar process is described in DE-A3437915. In this case, conventional polyester polycarboxylic acids are not built up from polyether polyols, but are reacted with polyether polyols and aliphatic alkanols.

According to EP-A0601470 (single-stage polycondensation), polycarboxylic acids, alkanediol mixtures and polyether polyols are condensed to give randomly distributed polyetherester polyols having ether to ester ratio of from 0.3 to 1.5 in the polyetherester polyol. A particular advantage of this process is that polyurethane flowable foams with reduced fogging can be prepared with these polyetherester polyols. The polyetherester polyols are reacted here with polyisocyanates.

It is therefore an object of the present invention to provide microcellular polyurethanes which have improved long-term flexural properties at room temperature and at-15 ℃ and subsequent hydrolytic aging (7 days at 70 ℃ and 95% atmospheric humidity).

It has surprisingly been found that polyetherester polyols comprising an alkane polyol mixture and a specific polyether polyol, which have a number average functionality of from 1.9 to 2.5, preferably from 1.95 to 2.1 and particularly preferably from 2.001 to 2.08 and whose ratio of ether groups to ester groups can be varied preferably from 0.3 to 2.5, preferably from 0.6 to 2.0 and particularly preferably from 0.9 to 1.5, react with polyisocyanates to give hydrolysis-resistant polyurethane elastomers which have very good long-term flexural strength before and after hydrolytic aging, with the proviso that the node density of the polyurethane elastomer is from 0.1mole/kg to 0.0001mole/kg, preferably from 0.08 to 0.001mole/kg, particularly preferably from 0.04 to 0.01 mole/kg.

The term "node density of the polyurethane elastomer" (unit: [ mole/kg ]) is understood to mean the number of trivalent permanent chemical crosslinking sites of the polyurethane elastomer, calculated as moles per kilogram of PU elastomer. For this purpose, the amount of substances comprising all the molecules of those starting materials for the polyurethane elastomer having a functionality of greater than 2. In order to be able to handle all crosslinking sites, such as trifunctional crosslinking sites, the functionality of the higher functional molecular species is measured differently: the trifunctional scale is 1, the tetrafunctional scale is 2, the pentafunctional scale is 3, the hexafunctional scale is 4, and so on. A polyurethane prepared according to this definition from the equivalent foam components polyester diol, 1, 4-butanediol, triethanolamine, pentaerythritol and a mixture of 1.21 wt.% 2, 4 '-diphenylmethane diisocyanate and 98.79 wt.% 4, 4' -diphenylmethane diisocyanate will have an elastomer node density of 0.69mole/kg, as can be seen from the calculations given by way of example in the table below.

Table: example of calculation of elastomer segment Density

Components	Mass [ g ]]	Molecular weight [ g/mol ]]	Amount of substance [ mole]	Functionality degree	Trifunctional crosslinking sites per molecule	Crosslinking Point [ mole/100g]	Crosslinking Point [ mole/kg]
								Polyester diol 1, 4-butanediol triethanolamine pentaerythritol MDI*	35.478.874.432.6648.57	3032.4390.12149.20136.20250.75	0.01170.09840.02970.01950.1937	22342	00120	0.0000.0000.0300.0390.000	0.000.000.300.390.00

The sum total 100.00 total crosslinking point-elastomer node density [ mole/kg ] 0.69 by 1.21 wt.% of a mixture of 2, 4 '-diphenylmethane diisocyanate and 98.79 wt.% of 4, 4' -diphenylmethane diisocyanate

The present invention accordingly provides polyurethane elastomers having a node density of from 0.1mole/kg to 0.0001mole/kg, preferably from 0.08 to 0.001mole/kg, particularly preferably from 0.04 to 0.01mole/kg, where the node density can be varied

d) Optionally a catalyst, which is added to the reaction mixture,

e) optionally a blowing agent and

f) optional additives

In the presence of a condition of

a) At least one polyetherester polyol having a number average molecular weight of from 1000g/mol to 6000g/mol, preferably from 2500g/mol to 5000g/mol, a number average functionality of from 1.9 to 2.5, preferably from 1.95 to 2.1 and particularly preferably from 2.001 to 2.08, and a ratio of polyetherester ether groups to ester groups of from 0.3 to 2.5, preferably from 0.6 to 2.0 and particularly preferably from 0.9 to 1.5, which can be prepared by reacting polyetherester polyols with at least one carboxylic acid

a1) At least one or more dicarboxylic acids having up to 12 carbon atoms and/or derivatives thereof,

a2) at least one or more polyether polyols having a number average molecular weight of 1000g/mol to 6000g/mol, preferably 2500g/mol to 5000g/mol, an average functionality of 1.7 to 2.5 and a primary OH content of 70% to 100%, preferably 85% to 96%, and

a3) at least one or more polyols having a number-average molecular weight of from 18 to 750g/mol, preferably from 18g/mol to 400g/mol, particularly preferably from 62g/mol to 200g/mol, a number-average functionality of from 2 to 8 and obtained by polycondensation having at least 2 terminal (primary) OH groups per molecule,

b) optionally a polymer polyol having an OH number of from 10 to 149 and an average functionality of from 1.7 to 4, preferably from 1.8 to 3.5 and which comprises from 1 to 50 wt.%, preferably from 1 to 45 wt.%, of filler, relative to the polymer polyol,

c) a low molecular weight chain extender having an average functionality of from 1.8 to 2.1 and a number average molecular weight of from 18g/mol to 750g/mol, preferably from 18g/mol to 400g/mol, particularly preferably from 62g/mol to 200g/mol, and/or a crosslinker having an average functionality of from 2.2 to 8, preferably from 2.5 to 4, and a number average molecular weight of from 18g/mol to 750g/mol, preferably from 18g/mol to 400g/mol, particularly preferably from 62g/mol to 200g/mol,

and

g) at least one polyisocyanate selected from

g1) An organic polyisocyanate, which is a polyisocyanate having a hydroxyl group,

g2) modified polyisocyanates and

g3) NCO prepolymers based on g1) and/or g2) and polyol x),

wherein the polyol x) is selected from

x1) of a polyester polyol,

x2) polyether ester polyols and

x3) x1) and x2),

g4) and mixtures of g1), g2) and g3)

And (4) reaction.

The term "polyetherester polyol" is understood to mean compounds having ether groups, ester groups and OH groups.

The polyetherester polyols a) used according to the invention have a number average molecular weight of from 1000g/mol to 6000g/mol, preferably from 2500g/mol to 5000g/mol, a number average hydroxyl functionality of from 1.9 to 2.5, preferably from 1.95 to 2.1, and particularly preferably from 2.001 to 2.08, and a ratio of ether groups to ester groups of from 0.3 to 2.5, preferably from 0.6 to 2.0, and particularly preferably from 0.9 to 1.5.

Organic dicarboxylic acids a1) having up to 12 carbon atoms are suitable for preparing the polyetherester polyols, preferably aliphatic dicarboxylic acids having 4 to 6 carbon atoms, alone or in mixtures. Examples which may be mentioned are suberic acid, azelaic acid, decanedicarboxylic acid, maleic acid, malonic acid, phthalic acid, pimelic acid and sebacic acid, and in particular glutaric acid, fumaric acid, butanedicarboxylic acid, adipic acid. The anhydrides thereof and the esters or half-esters thereof with low molecular weight monofunctional alcohols having from 1 to 4 carbon atoms are examples of derivatives of these acids which may be used.

As component a2) for the preparation of the polyetherester polyols, polyether polyols obtained by alkoxylation of starter molecules, preferably polyols, are used. The starter molecules are at least difunctional, but may optionally also comprise a content of higher-functional, in particular trifunctional, starter molecules. Alkoxylation is usually carried out in two steps. Alkoxylation, preferably with propylene oxide or less preferably 1, 2-butylene oxide or less preferably 2, 3-butylene oxide, is first carried out in the presence of a basic catalyst or double metal cyanide catalyst, followed by ethoxylation of ethylene oxide. The ethylene oxide content of the polyether polyol is 10 wt.% to 40 wt.%, preferably 15 wt.% to 35 wt.%.

Component a3) preferably comprises diols having primary OH groups and a number average molecular weight of 750g/mol or less, preferably from 18g/mol to 400g/mol, particularly preferably from 62g/mol to 200 g/mol; for example, 1, 2-ethanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentenediol, 1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 10-decanediol, 2-methyl-1, 3-propanediol, 2, 2-dimethyl-1, 3-propanediol, 3-methyl-1, 5-pentanediol, 2-butyl-2-ethyl-1, 3-propanediol, 2-butene-1, 4-diol and 2-butyne-1, 4-diol, ether diols, for example diethylene glycol, triethylene glycol, tetraethylene glycol, dibutylene glycol, tributylene glycol, tetrabutanediol, dihexanediol, trihexylene glycol, tetrahexylene glycol, and oligomeric mixtures of alkylene glycols, such as diethylene glycol.

In addition to diols, it is also possible to use polyols having a number average functionality of > 2 to 8, preferably 2.1 to 5, particularly preferably 3 to 4, such as, for example, 1, 1, 1-trimethylolpropane, triethanolamine, glycerol, sorbitan and pentaerythritol and also polyethylene oxide polyols which have an average molecular weight of less than 750g/mol, preferably 18g/mol to 400g/mol, particularly preferably 62g/mol to 200g/mol, and start with triols or tetrols.

Each diol may be used alone or in admixture with other diols and polyols. The diols and polyols can also be added subsequently to the polyester polyols, even if they do not react accordingly or do not react until the polycondensation equilibrium is reached in the esterification reaction. The relative amount of polyol used is limited by the number average hydroxyl functionality of a given polyetherester polyol a).

Polymer-modified polyols, in particular graft polymer polyols based on polyethers, polyesters or polyether esters, are suitable as polymer polyols b). Suitable graft components are particularly suitable those based on styrene and/or acrylonitrile, which are prepared by in situ polymerization of acrylonitrile, styrene or preferably mixtures of styrene and acrylonitrile, for example in a weight ratio of from 90: 10 to 10: 90, preferably from 70: 30 to 30: 70. Polyol dispersions which comprise as disperse phase, relative to the polymer polyol filler, for example inorganic fillers, Polyureas (PHDs), polyhydrazides, polyurethanes and/or melamines which comprise bonded tertiary amino groups as disperse phase, in amounts of generally from 1 to 50 wt.%, preferably from 1 to 45 wt.%, are also suitable as component b).

For the preparation of the polyurethane elastomers according to the invention, low molecular weight difunctional chain extenders, crosslinkers having a number average functionality of from 2.2 to 8 or mixtures of chain extenders and crosslinkers are additionally used as component c).

Such chain extenders and crosslinkers c) are used in order to modify the mechanical properties, in particular the hardness, of the polyurethane elastomers. Suitable chain extenders are the compounds as described under component a3), and diesters of phthalic acid with diols having 2 to 4 carbon atoms, for example bis-2-hydroxyethyl terephthalate or bis-4-hydroxybutyl terephthalate, hydroxyalkylene ethers of hydroquinone or resorcinol, for example 1, 4-bis- (. beta. -hydroxyethyl) hydroquinone or 1, 3- (. beta. -hydroxyethyl) resorcinol, N-alkyldialkanolamines having 2 to 12 carbon atoms, for example N-methyl-and N-ethyldiethanolamine. In addition to the crosslinkers mentioned under component a3), the crosslinkers are, for example, triols, tetraols, oligomeric polyalkylene polyols, aromatic and aliphatic amines and diamines having a functionality of from 2.2 to 8, preferably from 3 to 4, which generally have a molecular weight of 750g/mol or less, preferably from 18 to 400g/mol, particularly preferably from 62 to 200 g/mol.

The relative amounts of polyene and tetrahydric alcohol used are limited by the given node density of the polyurethane elastomer according to the invention and the average hydroxyl functionality of the polyetherester polyol a).

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

As component d) it is possible to use the amine catalysts currently used by the person skilled in the art, for example tertiary amines, such as triethylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, N, N, N ', N ' -tetramethylethylenediamine, pentamethyldiethylenetriamine and higher homologues, 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, diazabicycloundecene, monocyclic and bicyclic amidines, bis (dialkylamino) alkyl ethers, for example, bis (dimethylaminoethyl) ether, and tertiary amines having an amide group, preferably a carboxamide group. The following are also considered as catalysts: mannich bases prepared from secondary amines, which are known per se, are, for example, dimethylamine, and aldehydes, preferably formaldehyde, or ketones, such as acetone, methyl ethyl ketone, or cyclohexanone and phenols, such as phenol, N-nonylphenol or bisphenol a. Tertiary amines having hydrogen atoms as catalysts which are Zerewittinoff-active towards isocyanate groups are, for example, triethanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N, N-dimethylethanolamine, reaction products thereof with alkylene oxides, for example propylene oxide and/or ethylene oxide, and secondary-tertiary amines. Silamine having carbon-silicon bonds may also be used as a catalyst, such as 2, 2, 4-trimethyl-2-silamorpholine and 1, 3-diethylaminomethyl tetramethyldisiloxane. Further nitrogen-containing bases are contemplated, such as tetraalkylammonium hydroxides, and hexahydrotriazines. The reaction between the NCO groups and the zerewitinoff-active hydrogen atoms can also be accelerated considerably by lactams and azalactams.

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

For the preparation of microcellular polyurethane elastomers, preferably water is used as blowing agent e), which reacts in situ with isocyanate component g) to form carbon dioxide and amino groups, which in turn react further with further isocyanate groups to form urea groups and in this case act as chain extenders.

When water is added to the polyurethane formulation for adjusting the desired density, this is generally used in an amount of from 0.001 to 3.0 wt.%, preferably from 0.01 to 2.0 wt.%, and particularly preferably from 0.05 to 1.0 wt.%, relative to the weight of components a) to f).

Gaseous or volatile inorganic or organic substances which evaporate under the influence of the exothermic polyaddition reaction and preferably have a boiling point of from-40 to 120 ℃, preferably from-30 to 90 ℃ at standard pressure, and are physical blowing agents, can be used as blowing agents e) instead of or preferably in combination with water. For example acetone, ethyl acetate, halogenated or perhalogenated alkanes, for example R134a, R141b, R365mfc, R245fa, and further n-butane, iso-pentane, n-pentane, cyclopentane, n-hexane, iso-hexane, cyclohexane, n-heptane, iso-heptane or diethyl etherAre considered as organic blowing agents and are, for example, air, CO₂Or N₂O is considered as an inorganic blowing agent. Foaming can also be achieved by separating off gases, for example nitrogen and/or carbon dioxide, by adding compounds which decompose at temperatures above room temperature, for example azo compounds, such as azodicarbonamide or azo-bis-isobutyronitrile, or salts, such as ammonium hydrogen carbonate, ammonium carbamate or ammonium salts of organic carboxylic acids, such as monoammonium salts 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 ö chtlen (eds): "Kunststoff-Handbuch", volume VII, Carl-Hanser-Verlag, Munich, 3 rd edition, 1993, pp.115-118 and 710-715.

The amount of solid blowing agent, low-boiling liquid or gas which is advantageously used depends naturally on the desired density and the amount of water used, and can in each case be used individually or in the form of a mixture, for example as a liquid or gas mixture or gas-liquid mixture. The required amount can be readily determined by experiment. Amounts of solid, liquid and/or gas (in each case relative to the weight of components a) to f)) of 0.01 to 35 wt.%, preferably 0.1 to 6 wt.%, generally provide satisfactory results. Gases, for example air, carbon dioxide, nitrogen and/or helium, can be added either via the higher molecular weight polyhydroxyl compounds a) and b), via the compounds d) and f), or via the polyisocyanate g).

The reaction mixture for preparing the compact or microcellular polyurethane elastomers may optionally be supplemented with additives f). Examples which may be mentioned are surface-active additives, such as emulsifiers, foam stabilizers, cell regulators, flame retardants, nucleating agents, oxidation inhibitors, stabilizers, lubricants and mold release agents, dyes, dispersing assistants and pigments. For example, the sodium salt of castor oil sulfonic acid or the salts of fatty acids with amines, for example oleic acid diethylamine or stearic acid diethanolamine, come into consideration as emulsifiers. Sulfonic acids, e.g. dodecylbenzenesulfonic acid or dinaphthylmethanedisulfonic acid, or fatty acids, e.g. ricinoleic acid or polymeric estersAlkali metal salts or ammonium salts of fatty acids can also be used together as surface-active additives. Polyether siloxanes, in particular water-soluble representatives, are considered as foam stabilizers in the first place. These compounds are generally constructed such that a copolymer of ethylene oxide and propylene oxide is combined with a polydimethylsiloxane radical. Polysiloxane-polyoxyalkylene copolymers which are multiply branched by allophanate groups are particularly attractive. Other organopolysiloxanes, oxyethylated alkylphenols, oxyethylated fatty alcohols, paraffin oils, ricinoleates (Rizinus ö lsbergester) or ricinoleates (Ricinols Kandeer), sulfonated castor oils, peanut oils and pore regulators, such as paraffins, fatty alcohols and polydimethylsiloxanes, are also suitable. To improve the emulsification, the dispersion of the filler, the microporous structure and/or to stabilize it, oligomeric acrylates further having polyoxyalkylene groups and fluoroalkane groups as side groups are suitable. The surface-active substances are used in amounts of from 0.01 to 5 parts by weight, relative to 100 parts by weight of the high molecular weight polyhydroxyl compounds a) and b). Reaction retarders, antistatic agents, e.g. Catafor, may also be added^®Ca100, and further pigments or dyes and per se known flame retardants, and further stabilizers against ageing and weathering effects, plasticizers and fungistatic and bacteriostatic agents.

Further examples of surface-active additives and foam stabilizers and also cell regulators, reaction retarders, stabilizers, flame-retardant substances, plasticizers, dyes and fillers and fungistatic and bacteriostatic agents which may optionally be used together, and details concerning the use and mode of action of these additives are given in r.vieweg, a.h ö chtlen (eds): "Kunststoff-Handbuch", volume VII, Carl-Hanser-Verlag, Munich, 3 rd edition, 1993, page 118-.

Aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates corresponding to the formula g1) are suitable as component

Q(NCO)_n

Wherein n ═ 2 to 7, preferably 2, Q represents an aliphatic hydrocarbon group having 2 to 18, preferably 6 to 10 carbon atoms, an alicyclic hydrocarbon group having 4 to 15, preferably 5 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 15, preferably 6 to 13 carbon atoms, or an aromatic aliphatic hydrocarbon group having 8 to 15, preferably 8 to 13 carbon atoms; the following are suitable, for example: 1, 4-tetramethylene diisocyanate, 1, 6-Hexamethylene Diisocyanate (HDI), 1, 12-dodecyldiisocyanate, cyclobutane-1, 3-diisocyanate, cyclohexane-1, 3-diisocyanate and cyclohexane-1, 4-diisocyanate, 1-Isocyanato (Isocynato) -3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2, 4-and 2, 6-hexahydrotolylene diisocyanate, hexahydro-1, 3-and-1, 4-phenylene diisocyanate, Perhydro (Perhydro) -2, 4 '-diphenylmethane diisocyanate, Perhydro-4, 4' -diphenylmethane diisocyanate, 1, 3-and 1, 4-phenylene diisocyanate, 1, 4-naphthyl diisocyanate (1, 4-NDI), 1, 5-naphthyl diisocyanate (1, 5-NDI), 1, 4-Durol Diisocyanate (DDI), 4, 4 '-stilbene diisocyanate, 3, 3' -dimethyl-4, 4 '-biphenylene diisocyanate (TODI), 2, 4-and 2, 6-Tolylene Diisocyanate (TDI), diphenylmethane-2, 4', -2, 2 '-and-4, 4' -diisocyanate (MDI) and further nuclear representatives of the diphenylmethane diisocyanate series. The compounds mentioned and their isomers can be used in each case individually or in the form of mixtures.

It is preferred to use the polyisocyanates which are readily available industrially, for example 2, 4-and 2, 6-tolylene diisocyanate, naphthylene-1, 5-diisocyanate, 4, 4 '-diphenylmethane diisocyanate, 2, 2' -diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates, which are prepared by aniline-formaldehyde condensation followed by phosgenation ("crude MDI"), where the polyisocyanates can be used individually or in mixtures.

Mixtures of 4, 4 '-diphenylmethane diisocyanate and 2, 4' -diphenylmethane diisocyanate are particularly preferred.

For example, the following isocyanates g2 are considered as modified): polyisocyanates having carbodiimide groups, such as bis (4, 4' -diphenylmethane) carbodiimide, polyisocyanates having allophanate groups, polyisocyanates having isocyanurate groups, polyisocyanates having urea groups, polyisocyanates having acylated urea groups, polyisocyanates having biuret groups, polyisocyanates prepared by telomerization, the reaction products of the above-mentioned isocyanates with acetals, and polyisocyanates comprising polymerized fatty acid esters.

Particular preference is given to those modified polyisocyanates which are derived from 2, 4-and 2, 6-tolylene diisocyanate, from 4, 4 '-and/or 2, 4' -diphenylmethane diisocyanate or from naphthylene-1, 5-diisocyanate, and mixtures thereof.

The polyester polyols x2) are prepared by condensation of one or more dicarboxylic acids a1) with at least one or more polyols of component a3), c) and/or other short-chain polyols y) and with at least one or more long-chain polyols of component a2) or z).

The polyetherester polyols x2) can be identical to the polyetherester polyols a). However, they can also be prepared on the basis of polyether polyols or mixtures of polyether polyols z) having a number-average molecular weight of from 1000g/mol to 6000g/mol, preferably from 2500g/mol to 5000g/mol, and having an average functionality of from 1.7 to 2.5 and less than 70% primary OH groups. These polyether polyols z) are obtained by alkoxylation of starter molecules, preferably alcohols. The starter molecules are at least bifunctional, but may optionally also comprise higher functional, in particular trifunctional, starter molecule contents. Alkoxylation occurs in two steps. Alkoxylation with propylene oxide, 1, 2-butylene oxide or 2, 3-butylene oxide first using basic catalysis or double metal cyanide catalysis and optionally ethoxylation thereafter. The ethylene oxide content of the polyether is from 0 wt.% to 10 wt.%.

As component y), it is possible to use crosslinkers and chain extenders as described under c) and/or polyols having an average hydroxyl functionality of from 2 to 8, having one or two secondary hydroxyl groups and a number average molecular weight of less than 750 g/mol. They include saturated and unsaturated aliphatic diols, such as 1, 2-propanediol, 1, 2-butanediol, 1, 3-butanediol, ether glycols, such as dipropylene glycol, tripropylene glycol, tetrapropylene glycol, di-1, 2-butanediol, tri-1, 2-butanediol, tetra-1, 2-butanediol, di-1, 3-butanediol, tri-1, 3-butanediol, tetra-1, 3-butanediol and oligomer mixtures thereof.

In addition to diols, polypropylene oxide polyols starting from triols or tetraols, such as 1, 1, 1-trimethylolpropane, triethanolamine, glycerol and pentaerythritol having an average molecular weight of less than 750g/mol, can also be used.

Each of the compounds derived from the diols may be used by itself or in admixture with further diols and/or polyols. These diols or polyols can also be added subsequently to the polyester polyols, even if they do not react accordingly in the esterification reaction or do not react until the polycondensation equilibrium is reached. The relative amount of polyol used is limited by the number average hydroxyl functionality of a given polyetherester polyol x2) and the node density of a given polyurethane elastomer.

Polyester polyols x1) are prepared by condensation of one or more dicarboxylic acids a1) with at least one polyol or a plurality of polyols according to a3), c) and/or y).

The present invention therefore also provides a process for preparing the polyurethane elastomers according to the invention, which is characterized in that

d) Optionally a catalyst, which is added to the reaction mixture,

e) optionally a blowing agent and

f) optional additives

Under the condition that the water-soluble organic solvent exists,

a) at least one polyetherester polyol having a number average molecular weight of from 1000g/mol to 6000g/mol, a number average functionality of from 1.9 to 2.5, and a ratio of ether groups to ester groups of from 0.3 to 2.5,

which can be formed by

a1) At least one or more dicarboxylic acids having up to 12 carbon atoms or derivatives thereof,

a2) at least one or more polyether polyols having a number average molecular weight of 1000g/mol to 6000g/mol, an average functionality of 1.7 to 2.5 and a primary OH group content of 70% to 100%, and

a3) at least one or more polyols having a number average molecular weight of 18 to 750g/mol, a number average functionality of 2 to 8 and a polycondensation having at least 2 terminal OH groups per molecule,

b) optionally a polymer polyol having an OH number of from 10 to 149 and an average functionality of from 1.7 to 4 and which contains from 1 to 50 wt.% of filler, relative to the polymer polyol,

c) a low molecular weight chain extender having an average functionality of from 1.8 to 2.1 and having a number average molecular weight of from 18 to 750g/mol, and/or a crosslinker having an average functionality of from 2.2 to 8 and having a number average molecular weight of from 18 to 750g/mol

And

g) at least one polyisocyanate selected from

g1) An organic polyisocyanate, which is a polyisocyanate having a hydroxyl group,

g2) modified polyisocyanates and

g3) NCO prepolymers based on g1) and/or g2) and polyol x),

wherein the polyol x) is selected from

x1) of a polyester polyol,

x2) polyether ester polyols and

x3) x1) and x2),

g4) and g1), g2) and/or g 3).

Preferably, for the preparation of the polyetherester polyols a) or x2), the polycondensation of organic, for example aromatic and preferably aliphatic polycarboxylic acids and/or derivatives and polyols in the absence of a catalyst or in the presence of an esterification catalyst is advantageously carried out in solution and in the melt at a temperature of 150-.

According to a preferred preparation method, the esterification reaction is carried out at standard pressure until no more condensates are formed. After which the catalyst may be added. The reaction is carried out at a pressure of less than 500mbar, preferably from 2 to 150 mbar. As esterification catalysts there come into consideration, for example, iron catalysts in the form of metal oxides or metal salts, cadmium catalysts, cobalt catalysts, lead catalysts, zinc catalysts, antimony catalysts, magnesium catalysts, titanium catalysts and tin catalysts. However, the polycondensation can also be carried out in the presence of diluents and/or entrainers, for example benzene, toluene, xylene or chlorobenzene, in order to separate the condensation water azeotropically. Mixtures of the agents mentioned are likewise customary.

For the preparation of the polyester polyols x1), organic polycarboxylic acids and/or derivatives thereof are preferably used with polyols in a quantity ratio such that the hydroxyl groups are always present in excess relative to the carboxyl groups or carboxyl derivatives.

The polyurethane elastomers according to the invention are preferably prepared by a prepolymer process, wherein prepolymer g3) is advantageously obtained by reacting at least one polyol or a plurality of polyols x) with at least one or a plurality of isocyanates g1) and optionally modified isocyanates g2) and optionally short-chain polyols a3) and/or y) and/or c).

To prepare the solid or microcellular polyurethane elastomers according to the invention, the isocyanate g) comprising component g1) and optionally component g2) or preferably NCO prepolymer g3) is preferably reacted with at least one polyetherester polyol a) and low molecular weight chain extenders and/or crosslinkers c), optionally with addition of catalysts d), blowing agents e) and additives f).

To prepare the polyurethane elastomers according to the present invention, the components are reacted in the following amounts: the equivalent ratio of NCO groups of isocyanate g) to the total number of hydrogen atoms of components a), b), c), d) and f), and any chemically acting blowing agent e) which may be used, is from 0.8: 1 to 1.2: 1, preferably from 0.95: 1 to 1.15: 1 and in particular from 1.00: 1 to 1.05: 1, where the hydrogen atoms of components a), b), c), d) and f) are reactive toward isocyanate groups.

Further, all components according to the invention, in view of their isocyanate functionality and hydroxyl functionality, are combined such that the resulting polyurethane elastomer has a node density of from 0.1mole/kg to 0.0001mole/kg, preferably from 0.001 to 0.08mole/kg, particularly preferably from 0.01 to 0.04 mole/kg.

The polyurethane elastomers according to the invention are preferably used in the production of shoe parts, in particular shoe soles.

The present invention will be explained in further detail with reference to the following examples.

Examples

The polyurethane elastomers are obtained by equivalent reaction of a polyol formulation α and an NCO prepolymer β (average functionality 2.01). The composition of polyol formulation alpha and NCO prepolymer beta can be seen in table 2. The physical properties of the polyurethane elastomer according to the present invention are shown in Table 3.

General guidance for the preparation of polyetherester polyols is described by way of example for polyetherester polyol C.

4662g (53.7mole) of a hydroxyl-functionalized polyether P (hydroxyl number 28; number average hydroxyl functionality 1.81; primary hydroxyl groups 90 mol.% (propylene glycol as starting material; 68.7 wt.% propylene oxide; 29.4 wt.% ethylene oxide)), 426g (4mole) of diethylene glycol, 417g (4.8mole) of ethylene glycol, 767g (8.8mole) of 1, 4-butanediol, 15g (0.1mole) of trimethylolpropane and 2461g (16.8mole) of adipic acid were heated to a melt in a10 liter four-neck flask fitted with a stirrer, a packed column, an overhead condenser and thermometer and vacuum pump and heating mantle and passed through the apparatus with nitrogen. Heating to 180 ℃ was continued until no further water separated. Thereafter 200mg of tin (II) chloride are added, vacuum is slowly applied and the temperature is raised to 200 ℃. Stirring was continued for 2 hours at 200 ℃ and 5mbar in order to complete the reaction. A polyether ester having an acid number of 0.3, a hydroxyl number of 34.6 and a viscosity of 930 mPas at 75 ℃ was obtained. The physical data of the starter compounds and of the polyetherester polyols and polyester polyols are shown in Table 1.

Polyurethane test pieces were prepared such that the polyol formulation α at 55 ℃ was mixed with the NCO prepolymer β at 40 ℃ in a low pressure foaming device at 3000rpm with a tooth mixer, the mixture was poured into an aluminum hinged mold (200 × 140 × 10mm) controlled at 50 ℃ and the hinged mold was closed, and after 3.5 minutes the polyurethane elastomer was demolded.

The Shore A hardness according to DIN 53505 was determined after 24 hours of storage by means of blue gel on the polyurethane elastomer plates thus obtained. After 30,000 bending cycles, the puncture-type crack growth was further determined according to DIN 53522 for a 2mm wide puncture through the bending line of a test piece (2 cm. times.15 cm. times.1 cm) supported by a Texon strip. The results are shown in table 3. The bending endurance test was performed at room temperature and at-15 ℃. The test pieces were further aged at 70 ℃ for 7 days at 95% atmospheric humidity and were dried at 70 ℃ for 24 hours. Conditioned for an additional 24 hours at room temperature, after which they were subjected to a long-term bending test at room temperature. The friction was determined in accordance with DIN 53516, and the oil resistance (Kraft flexible sheet) was determined in accordance with EN 344.

Table 1: polyetherester polyols C, E to O, and polyester polyols A, B and D, component a3)

	Hydroxyl number (mg KOH/g)	Acid value (mg KOH/g)	Viscosity of the oil75℃[mPa.s]	Molecular weight (g/mol)	Number average hydroxyl functionality	Ethylene glycol [ wt. ]%]	1, 4-butanediol [ wt. ]%]	Diethylene glycol [ wt. ]%]	Trimethylolpropane [ wt. ]%]	Polyether P [ wt. ]%]	Adipic acid [ wt. ]%]
												ABCDEFGHIJKLMNO	29.037.034.635.735.038.337.037.5039.134.737.236.531.340.438.90	0.50.70.30.60.60.40.40.30.30.40.40.40.80.30.8	28001900930190013508301330960107011801160116014309201040	386930323303320132652984308930472923329331313074365128292942	2.0002.0002.0372.0372.0372.0372.0372.0372.0372.0372.0762.0002.0372.0372.040	0.20760.20850.04810.10060.1082-0.05030.09390.05830.07490.06530.06670.06700.06590.0655	0.12910.13000.08830.18880.09930.15240.1846-0.10690.13740.11980.12190.11850.12090.1231	--0.04030.08610.04530.06950.04210.07870.0976-0.05360 05440.05380.05490.0545	--0.00170.00160.00160.00170.00160.00170.00170.00170.0033-0.00120.00180.0016	--0.5379-0.30240.46420.28130.52490.32540.41850.36510.36430.36230.36750.3650	0.6630.6610.2840.6230.4430.3120.4400.3010.4100.3680.3930.3930.3970.3890.390

Table 2: composition of polyol formulation alpha and prepolymer beta polyol formulation alpha

Components	[wt.％]
		Polyhydric alcohols B to O of butanediol diazabicyclooctane triethanolamine aqueous foam stabilizers	13.01
0.560.19
	0.320.0985.83
100.00

NCO prepolymer beta

Components	[wt.％]
		Desmodur®44MDesmodur®CD polyol A	46.324.9648.72
100.00

Desmodur^®: isocyanates, commercially available from Bayer AG

Table 3: having a density of 600kg/m³Properties of Density polyurethane elastomer test specimens

Test of	Polyol in polyol formulation alpha	Average functionality of polyol formulation alpha	Hardness (Shore A)	Long term bending strength at room temperature				Long term bending strength at-15 DEG C				Long term flexural strength after hydrolytic aging at room temperature				Rub (ng)]	Oil resistance swelling Rate [% ]]	Node density [ mole/kg]
																			Crack propagation of 30,000 bend post-puncture type		Break after n bends		Crack propagation of 30,000 bend post-puncture type		Break after n bends		Crack propagation of 30,000 bend post-puncture type		Break after n bends
				Number of x	Broadening [ nm ]]	Number of y	n times of bending	Number of x	Broadening [ nm ]]	Number of y	n times of bending	Number of x	Broadening [ nm ]]	Number of y	n times of bending
																			*B	B	2.0085	64	0		4	22500	2	4.7	3	21667	0		4	4.185	78	1	0.0177
C′	C	2.0142	63	4	3.0	0		3	4.4	1	30000	3	8.7	1	30.000	92	6	0.0229
																			*D′	D	2.0143	62	0		4	11300	0		4	16300	4	1.5	0		42	1	0.0231
E′	E	2.0142	61	0		4	20000	0		4	27500	4	7.7	0		68	1	0.0230
																			F′	F	2.0145	62	3	3.4	1	30000	3	5.0	1	25000	4	5.8	0		70	7	0.0234
G′	G	2.0144	61	0		4	22500	0		3	23300	4	3.1	0		62	3	0.0232
																			H′	H	2.0149	61	4	2.2	0		4	2.2	0		3	13.6	1		94	6	0.0237
I′	I	2.0148	60	4	3.8	0		4	4.0	0		4	6.7	0		86	4	0.0235
																			J′	J	2.0142	62	4	1.5	0		4	1.2	0		4	8.2	0		68	5	0.0229
K′	K	2.0203	61	0		4	30000	3	9.9	1	30000	4	2.9	0		62	4	0.0286
																			L′	L	2.0085	60	4	1.1	0		4	0.6	0		0		4	13.800	66	5	0.0177
M′	M	2.0138	60	4	1.6	0		4	1.1	0	5000	0		4		95	4	0.0224
																			N′	N	2.0148	61	2	9.1	2	30000	3	6.1	1	30000	4	4.0	0		75	4	0.0237
O′	O	2.0146	64	4	1.8	0		4	3.5	0		0		4	17.675	68	4	0.0235

^*Comparison

The letters "x" and "y" when added give the number of test strips that have been subjected to the bend resistance test. The letter "x" indicates the number of test strips with a puncture type crack growth (stichaufweitung) and "y" indicates the number of broken test strips.

Claims (8)

1. The polyurethane elastomer having a node density of 0.1mole/kg to 0.0001mole/kg can be obtained by

d) Optionally a catalyst, which is added to the reaction mixture,

e) optionally a blowing agent and

f) optional additives

Under the condition that the water-soluble organic solvent exists,

a) at least one polyetherester polyol having a number average molecular weight of from 1000g/mol to 6000g/mol, a number average functionality of from 1.9 to 2.5, and a ratio of ether groups to ester groups of from 0.3 to 2.5,

which can be formed by

a1) At least one or more dicarboxylic acids having up to 12 carbon atoms or derivatives thereof,

a2) at least one or more polyether polyols having a number average molecular weight of 1000g/mol to 6000g/mol, an average functionality of 1.7 to 2.5 and a primary OH group content of 70% to 100%, and

a3) at least one or more polyols having a number average molecular weight of 18 to 750g/mol, a number average functionality of 2 to 8 and having at least 2 terminal OH groups per molecule

Is obtained by polycondensation, and has the advantages of,

b) an optional polymer polyol having an OH number of from 10 to 149 and an average functionality of from 1.7 to 4, and which contains from 1 to 50 wt.% of filler, relative to the polymer polyol,

c) a low molecular weight chain extender having an average functionality of from 1.8 to 2.1 and having a number average molecular weight of from 18 to 750g/mol, and/or a crosslinker having an average functionality of from 2.2 to 8 and having a number average molecular weight of from 18 to 750g/mol

And

g) at least one polyisocyanate selected from

g1) An organic polyisocyanate, which is a polyisocyanate having a hydroxyl group,

g2) modified polyisocyanates and

g3) NCO prepolymers based on g1) and/or g2) and a polyol x), wherein the polyol x) is selected from

x1) of a polyester polyol,

x2) polyether ester polyols and

x3) x1) and x2),

g4) and g1), g2) and/or g 3).

2. A polyurethane elastomer according to claim 1 characterised in, that polyisocyanate g1) is 4, 4 '-diphenylmethane diisocyanate, 2, 4' -diphenylmethane diisocyanate or a mixture thereof.

3. A polyurethane elastomer according to claim 1, characterised in that the polyol a3) is selected from 1, 4-butanediol, 1, 2-ethanediol, diethylene glycol, hexanediol, trimethylolpropane, sorbitan, pentaerythritol, triethanolamine and glycerol.

4. Process for preparing a polyurethane elastomer according to any one of claims 1 to 3, characterized in that

d) Optionally a catalyst, which is added to the reaction mixture,

e) optionally a blowing agent and

f) optional additives

Under the condition that the water-soluble organic solvent exists,

a) at least one polyetherester polyol having a number average molecular weight of from 1000g/mol to 6000g/mol, a number average functionality of from 1.9 to 2.5, and a ratio of ether groups to ester groups of from 0.3 to 2.5,

which can be formed by

a1) At least one or more dicarboxylic acids having up to 12 carbon atoms or derivatives thereof,

a2) at least one or more polyether polyols having a number average molecular weight of 1000g/mol to 6000g/mol, an average functionality of 1.7 to 2.5 and a primary OH group content of 70% to 100%, and

a3) at least one or more polyols having a number average molecular weight of 18 to 750g/mol, a number average functionality of 2 to 8 and having at least 2 terminal OH groups per molecule

Is obtained by polycondensation, and has the advantages of,

b) an optional polymer polyol having an OH number of 10 to 149 and a level of 1.7 to 4

A homofunctionality and which comprises from 1 to 50 wt.% of a filler, relative to the polymer polyol,

c) a low molecular weight chain extender having an average functionality of 1.8 to 2.1 and having a number average molecular weight of 18g/mol to 750g/mol, and/or a crosslinker having an average functionality of 2.2 to 8 and having a number average molecular weight of 18g/mol to 750g/mol

And

g) at least one polyisocyanate selected from

g1) An organic polyisocyanate, which is a polyisocyanate having a hydroxyl group,

g2) modified polyisocyanates and

g3) NCO prepolymers based on g1) and/or g2) and a polyol x), wherein the polyol x) is selected from

x1) of a polyester polyol,

x2) polyether ester polyols and

x3) x1) and x2),

g4) and g1), g2) and/or g 3).

5. Use of a polyurethane elastomer according to any of claims 1 to 3 for the production of elastomeric moulded parts.

6. Use according to claim 5, the elastomeric moulding having a viscosity of 180-³The sole of the shoe of (1).

7. Elastomeric moulded parts for industrial and consumer products produced from the polyurethane elastomer according to any one of claims 1 to 3.

8. An elastomeric moulding according to claim 7 which is a shoe sole.