WO2005019296A1

WO2005019296A1 - Thermoplastic polyurethane containing silane groups

Info

Publication number: WO2005019296A1
Application number: PCT/EP2004/007268
Authority: WO
Inventors: Oliver Steffen Henze; Sabine Peters; Johann Diedrich Brand; Christa Hackl; Markus Krämer; Klaus Hilmer
Original assignee: Basf Aktiengesellschaft
Priority date: 2003-07-25
Filing date: 2004-07-03
Publication date: 2005-03-03
Also published as: DE10334266A1; DE112004000836D2

Abstract

The invention relates to thermoplastic polyurethane based on polyisocyanates (x) which are provided with at least one organosilicon group (silane group).

Description

THERMOPLASTIC POLYURETHANE CONTAINING SILANE GROUPS

description

The invention relates to thermoplastic polyurethane, in particular fibers and hoses, in particular compressed air hoses, and cable sheathing based on polyisocyanates (x), preferably diisocyanates, triisocyanates, tetraisocyanates, pentaisocyanates and / or hexaisocyanates (x), particularly preferably diisocyanates (x), which have at least one, preferably one to five, particularly preferably one to three, in particular one organic silicon groups, also referred to in this document as silane groups. Furthermore, the invention relates to processes for the production of organic silicon groups, in this document also as silane-modified, i.e. Thermoplastic polyurethane having organic silicon groups and crosslinkable TPU obtainable in this way, in particular cable sheathing, fibers or hoses, in particular compressed air hoses, and the corresponding products crosslinked via the silane groups. The invention also relates to cable sheathing, fibers or hoses, in particular compressed air hoses, based on thermoplastic polyurethane which is crosslinked via silane groups, in particular siloxane groups, in particular cable sheathing, fibers or hoses in which the crosslinked thermoplastic polyurethane has a Shore-A hardness between 85 and 98 and a Vicat temperature according to DIN EN ISO 306 (10N / 120 K / h) of greater than 130 ° C, particularly preferably greater than 140 ° C, in particular greater than 145 ° C.

Thermoplastic plastics are plastics that, when repeatedly heated and cooled in the temperature range typical for the material for processing and application, remain thermoplastic. Thermoplastic is understood to mean the property of a plastic to repeatedly soften in the heat in a temperature range typical for it and to harden on cooling and in the softened state to be capable of being repeatedly formed by molding, extrudate or molded part into semi-finished products or objects. Thermoplastic materials are widely used in technology and can be found in the form of fibers, sheets, foils, moldings, bottles, jackets, packaging, etc. Thermoplastic polyurethane (hereinafter referred to as TPU) is an elastomer that is used in many applications , eg shoe applications, foils, fibers, ski boots, hoses. The advantage that the TPU offers due to the possibility of thermoplastic processability, however, is at the same time a disadvantage of these materials in view of the lower heat resistance compared to crosslinked polymers. It would therefore be desirable to take advantage of thermoplastic processing to combine those of the excellent heat resistance of cross-linked polymers.

From US 2002/0169255 and the publication: S. Dassin et al in Polymer Engineering and Science, August 2002, Vol. 42, No. 8 is taught in view of this goal of modifying a thermoplastic polyurethane with a silane, the silane being coupled to the polyurethane by means of a crosslinker. By hydrolysis of the silane, e.g. after shaping, a crosslinking of the originally thermoplastic polyurethane is achieved. A disadvantage of this technical teaching is that a number of individual steps are required to obtain the networked TPU. Starting from the thermoplastic polyurethane, two reactions are necessary, first with the cross-linked and then with the silane. According to US 2002/0169255, the use of the crosslinking agent, which binds the silane to the TPU, is necessary since direct use of the silane is said to lead to degradation of the TPU.

The object of the present invention was to develop thermoplastic polyurethane, in particular fibers, cable sheaths or hoses, in particular compressed air hoses based on thermoplastic polyurethane, containing silane groups, which are accessible via a simple, quick and inexpensive production process, have excellent crosslinking properties and in particular in Use as fibers have a very good level of properties when cross-linked.

These tasks could be solved by the thermoplastic polyurethanes and products shown at the beginning. According to this invention the silane, i.e. the silicon-organic compound built directly into the polyurethane. In contrast to the teaching according to US 2002/0169255, it is not connected to the TPU indirectly, via a crosslinker, but is present in the TPU structure itself. If "silane" is mentioned in this document, this term is to be understood in particular as meaning organosilicon compounds.

The polyisocyanate (x), preferably diisocyanate (x) containing at least one silane group, is preferably bonded via two urethane groups with (b) isocyanate-reactive compounds with a molecular weight between 500 and 10,000 and / or with (c) chain extenders with a molecular weight of 50 to 499 in the thermoplastic polyurethane. This means that the compound with which the silane is introduced into the TPU, ie component (x), via the at least two isocyanate groups of component (x) with the isocyanate-reactive groups of component (b) and / or (c) , in particular the hydroxyl groups of components (b) and / or (c) and is incorporated into the TPU. Lying there preferably no allophanate groups between the two urethane groups and the silane groups.

Another object was to provide an improved, simpler, faster and more economical process for producing crosslinkable TPU, in particular processes for producing silane-modified, i.e. To develop silane groups containing thermoplastic polyurethane.

This object was achieved by using polyisocyanates (x), preferably diisocyanates, triisocyanates, tetraisocyanates, pentaisocyanates and / or hexaisocyanates (x), particularly preferably diisocyanates (x), in the production of the thermoplastic polyurethane, which contain at least one, preferably have one to five, particularly preferably one to three, in particular a silicon-organic group.

The method according to the invention is characterized in that the silane group can be introduced directly during the manufacturing process of the TPU. Complicated additional steps such as the implementation of a finished TPU with isocyanates and the subsequent implementation of the isocyanate-modified TPU with silanes, e.g. taught in US 2002/0169255 are not required. It was surprisingly found that the silane groups, which are already integrated into the TPU during the manufacturing process, do not lead to cross-links in the further processing of the TPU before the actual shaping. This is surprising since the processing of the TPU, e.g. granulation is carried out under water, if appropriate in the presence of moisture, which can be followed by drying at elevated temperatures. These moist and warm conditions usually support the crosslinking reaction of the silanes, but this only takes place after the actual shaping, i.e. after extrusion, injection molding or spinning is desired.

According to the invention, the silanes can thus already be incorporated in the TPU production process. Silanes can be used which have at least two, preferably two, isocyanate groups.

The thermoplastic polyurethane is preferably prepared in such a way that the thermoplastic polyurethane is prepared by reacting (x) polyisocyanates which have at least one silane group and optionally isocyanates (a) which have no silane group with (b) compounds which are reactive toward isocyanates with a Molecular weight between 500 and 10,000 and (c) chain extenders with a molecular weight of 50 to 499. The molar ratio is the sum of the isocyanate groups of component (x) and, if appropriate, that Isocyanate groups of component (a) to the sum of the isocyanate-reactive functions of components (b) and (c) preferably between 0.9: 1 and 1.2: 1, particularly preferably between 0.95: 1 and 1.15: 1 This preferred ratio thus describes the molar ratio of all isocyanate groups to the sum of all functions which are reactive toward isocyanates, ie reactive hydrogen atoms. This ratio is usually also referred to as a key figure, a ratio of 1: 1 corresponding to a key figure of 100. If the index is 100, there is one active hydrogen atom for each isocyanate group of component (a), ie a function that is reactive towards isocyanates. With key figures above 100, there are more isocyanate groups than, for example, OH groups.

As an alternative to the above-mentioned process, the crosslinkable TPUs according to the invention can also be prepared by reacting thermoplastic polyurethane with polyisocyanates (x) which have at least one silane group. The silanes, i.e. component (x), which have two or more isocyanate groups, is attached to a finished TPU. The TPU can preferably be in the molten or softened, particularly preferably molten state, for example in an extruder with the silane, i.e. component (x) are reacted. However, the silane groups are preferably already integrated into the TPU during the production of the TPU.

Component (x) or the expression “silane groups” in this document means compounds, in particular generally known alkoxysilanes, for example di- or tri-methoxy and / or ethoxysilanes, which have at least two isocyanate groups and preferably the following general Have structure:

-Si (R) _3-x (OR) _x

with the following meaning for R and x:

R: alkyl radical or aryl radical, which can optionally be heteroatom-substituted, preferably alkyl radical with 1 to 10, preferably 1 to 6 carbon atoms, preferably methyl and / or ethyl,

x: 1, 2 or 3, preferably 2 or 3, particularly preferably 3,

wherein the three alkyl radicals marked with R in the silane can be identical or different from one another, are preferably the same. Corresponding compounds which preferably have two isocyanate groups can also be prepared by reacting preferably compounds which have at least three, preferably three to 10, particularly preferably 3 to 5, in particular 3 isocyanate groups with silanes which have a group which is reactive toward isocyanates , in particular have a secondary amino group. A silane which has two isocyanate groups and is obtainable by reacting compounds which have three isocyanate groups with silanes which have a function which is reactive toward isocyanates is preferably used.

The following compounds, for example, can be used as compounds which have three isocyanate groups:

Basonat® 100 (BASF Aktiengesellschaft), toluene triisocyanurate, 1, 8-diisocyanato-4- (isocyanatomethyl) octane, 1, 6.11 -undecatriisocyanate, 1, 3,6-hexamethylenetriisocyanate.

The following compounds are preferred: 1, 8-diisocyanato-4- (isocyanatomethyl) octane, 1, 6,11 -undecatriisocyanate, 1, 3,6-hexamethylenetriisocyanate and / or poly-MDI with an average isocyanate functionality of at least 2.5 and / or isocyanurate, e.g. based on hexamethylene diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanato-methyl-cyclohexane (isophorone diisocyanate, IPDI), 1, 4- and / or 1, 3-bis (isocyanatomethyl) cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 1-methyl-2,4- and / or -2,6-cyclohexane di-isocyanate and / or 4,4'-, 2,4'- and 2, 2'-dicyclohexylmethane diisocyanate, 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1, 5-naphthylene diisocyanate (NDI), 2,4- and / or 2nd , 6-tolylene diisocyanate (TDI).

As silanes which have an isocyanate-reactive group, in particular a secondary amino group, e.g. Compounds of the following general formula are used: Compounds of the following general formula are preferred:

R _r NH-R ₂ -Si (R) _3-x (OR) _x

with the following meaning for R ₂ , Ri, R and x:

R ₂ : aliphatic, araliphatic or aromatic, optionally branched, optionally substituted, optionally substituted, optionally containing heteroatoms hydrocarbon radical having 1 to 30 carbon atoms, preferably one to three carbon atoms, in particular three carbon atoms, particularly preferably methylene, ethylene or propylene, in particular propylene, R ^ aliphatic, araliphatic or aromatic, optionally branched, optionally substituted, optionally substituted, optionally heteroatoms-containing hydrocarbon radical having 1 to 30 carbon atoms, preferably one to three, in particular one carbon atom, or a proton (-H)

R: alkyl radical or aryl radical, which may optionally be heteroatom-substituted, preferably alkyl radical having 1 to 10, preferably 1 to 6 carbon atoms, preferably methyl and / or ethyl,

x: 1, 2 or 3, preferably 2 or 3, particularly preferably 3,

wherein the three alkyl radicals marked with R in the silane can be identical or different from one another, are preferably the same.

Bis- (gamma-trimethoxysilylpropyl) amines, N-ethyl-gamma-aminoisobutyltrimethoxysilanes, N-phenyl-gamma-aminopropyltrimethoxysilanes, 4-amino-3,3-dimethylbutyltrimethoxysilanes, gamma-aminopropyltrimethoxysilanes, gamma-aminopropyltrimethoxysilanes, particularly preferred are aminomethyl-trimethoxysilane, N-phenyl-aminomethyl-dimethoxymethylsilane, N-phenyl-aminomethyl-diethoxyethylsilane, N-phenyl-aminomethyl-triethoxysilane, especially N-phenyl-aminomethyl-dimeth-oxymethylsilane.

If the production of the TPU in the presence of the silane, i.e. component (x), the molar ratio of the isocyanates (a) to the polyisocyanates (x), preferably diisocyanates (x), preferably between 1: 0.01 and 1: 100, preferably 1: 0.02 to 1:50.

If, according to the second alternative, TPU that has already been produced is modified with component (x), between 0.001 and 0.2 mol of silane are preferably used per 100 g of thermoplastic polyurethane.

Thermoplastic polyurethane means that it is preferably a thermoplastic elastomer based on polyurethane.

Particularly suitable thermoplastic polyurethane are TPUs that have a Shore hardness of 50 A 80 D. Also preferred are TPUs that have one, more or preferably all of the following properties: TPUs with

• an elastic modulus of 10 MPa to 10,000 MPa measured according to DIN EN ISO 527-2 on a sample body of type A according to DIN EN ISO 3167 at a test speed of 1 mm / min. From the initial slope of the voltage The elongation curve is calculated as the ratio of tension and elongation.

• a glass transition temperature T _g measured by DSC (at 10K / min) less than minus 10 ° C for types up to a maximum of 64 Shore D types up to less than minus 40 ° C for types minimum 85 Shore A types.

• an impact strength according to Charpy according to DIN 53453 (DIN EN ISO 179) to minus 60 ° C without break and a notched impact strength less than minus 40 ° C for types less than 95 Shore A types and less than minus 20 ° C for types up to a maximum of 60 Shore D types , • a density according to DIN 53479 or ISO 1183 between 1.05 and 1.30 g / cm ³

• a tensile strength greater than 40 MPa measured according to DIN 53504 or ISO 37 for non-plasticized TPU types

• a tear resistance measured according to DIN 53515 or ISO 34 greater than 65 MPa for (non-plasticized) types less than 95 Shore A types and greater than 100 MPa for types greater than 50 Shore D.

• an abrasion of less than 40 mm ³ measured according to DIN 53516 or ISO 4649

• a compression set at 70 ° C measured according to DIN 53517 or ISO 815 between 30 and 70%

The TPU exhibits these preferred properties in the uncrosslinked state, i.e. without cross-linking via the silane groups.

Processes for the production of thermoplastic polyurethanes, also referred to in this document as TPU, are generally known. In general, TPUs are obtained by reacting (a) isocyanates with (b) isocyanate-reactive compounds, usually with a molecular weight (M _w ) of 500 to 10,000, preferably 500 to 5000, particularly preferably 800 to 3000 and (c) chain extenders with a molecular weight of 50 to 499 optionally in the presence of (d) catalysts and / or (e) customary additives. As already mentioned at the beginning, polyisocyanates (x), preferably diisocyanates (x), which have at least one silane group, are used according to the invention. This component (x) can be used as the sole isocyanate component or, preferably, in addition or as a partial replacement for the customary isocyanate component (a).

The starting components and processes for the production of the preferred polyurethanes are to be described below by way of example. The components (a), (b), (c) and, if appropriate, (d) and / or (e) normally used in the production of the polyurethanes are to be described by way of example below: a) Generally known aliphatic, cycloaliphatic, araliphatic and / or aromatic isocyanates can be used as organic isocyanates (a), for example tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2- Methyl-pentamethylene-diisocyanate-1, 5, 2-ethyl-butylene-diisocyanate-1, 4, pentamethylene-diisocyanate-1, 5, butylene-diisocyanate-1, 4, 1 -isocyanato-3,3, 5-trimethyl-5-isocyanato-methyl-cyclohexane (isophorone diisocyanate, IPDI), 1,4- and / or 1,3-bis (isocyanatomethyl) cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 1 -Methyl-2,4- and / or -2,6-cyclohexane di-isocyanate and / or 4,4'-, 2,4'- and 2,2'-dicyclohexylmethane diisocyanate, 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1, 5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-tolylene diisocyanate (TDI), diphenylmethane diisocyanate, 3,3'- Dimethyl diphenyl diisocyanate, 1, 2-diphenylethane diisocyanate and / or phenylene diisocyanate. 4,4'-MDI is preferably used. To distinguish the isocyanates (a) from the silanes, isocyanates (a) only include those isocyanates which have no silane group.

b) The compounds (b) which are reactive toward isocyanates can be the generally known compounds which are reactive toward isocyanates, for example polyesterols, polyetherols and / or polycarbonate diols, which are usually also summarized under the term "polyols", with molecular weights between 500 and 8000 , preferably 600 to 6000, in particular 800 to less than 3000, and preferably an average functionality compared to isocyanates of 1.8 to 2.3, preferably 1.9 to 2.2, in particular 2. Polyether polyols are preferably used, for example those based on generally known starter substances and customary alkylene oxides, for example ethylene oxide, propylene oxide and / or butylene oxide, preferably polyetherols based on propylene oxide-1, 2 and ethylene oxide and in particular polyoxetetramethylene glycols. The polyetherols have the advantage that they have a higher hydrolysis stability than polyesterols.

So-called low-unsaturated polyetherols can also be used as polyetherols. In the context of this invention, low-unsaturated polyols are understood in particular to mean polyether alcohols with an unsaturated compound content of less than 0.02 meg / g, preferably less than 0.01 meg / g.

Such polyether alcohols are mostly produced by addition of alkylene oxides, in particular ethylene oxide, propylene oxide and mixtures thereof, onto the diols or triols described above in the presence of highly active catalysts. Such highly active catalysts are, for example, cesium hydroxide and multimetal cyanide catalysts, also referred to as DMC catalysts. A frequently the set DMC catalyst is zinc hexacyanocobaltate. After the reaction, the DMC catalyst can be left in the polyether alcohol; it is usually removed, for example by sedimentation or filtration.

Furthermore, polybutadiene diols with a molar mass of 500-10000 g / mol, preferably 1000-5000 g / mol, in particular 2000-3000 g / mol can be used. TPUs which have been produced using these polyols can be crosslinked by radiation after thermoplastic processing. This leads e.g. for better burning behavior.

Instead of a polyol, mixtures of different polyols can also be used.

c) Generally known aliphatic, araliphatic, aromatic and / or cycloaliphatic compounds with a molecular weight of 50 to 499, preferably 2-functional compounds, are used as chain extenders (c), for example diamines and / or alkanediols with 2 to 10 carbon atoms. Atoms in the alkylene radical, in particular 1,3-propanediol, 1,4-butanediol, 1, 6-hexanediol and / or di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- and / or decaalkylene glycols with 3 to 8 carbon atoms, preferably corresponding oligo- and / or polypropylene glycols, it also being possible to use mixtures of the chain extenders.

Components a) to c) are particularly preferably difunctional compounds, i.e. Diisocyanates (a), difunctional polyols, preferably polyetherols (b) and difunctional chain extenders, preferably diols.

d) Suitable catalysts, which in particular accelerate the reaction between the NCO groups of the diisocyanates (a) and the hydroxyl groups of the structural components (b) and (c), are the conventional tertiary amines known and known in the art, such as, for example Triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N, N'-dimethylpiperazine, 2- (dimethylaminoethoxy) ethanol, diazabicyclc— (2,2,2) octane and the like and in particular organic metal compounds such as titanium acid esters, iron compounds such as, for example Iron (III) acetylacetonate, tin compounds, for example tin diacetate, tin dioctoate, tin dilaurate or the tin dialkyl salts of aliphatic carboxylic acids such as dibutyltin diacetate, dibutyltin dilaurate or the like. The catalysts are usually used in amounts of 0.0001 to 0.1 part by weight per 100 parts by weight of polyhydroxyl compound (b). e) In addition to catalysts (d), customary auxiliaries and / or additives (e) can also be added to the structural components (a) to (c). Examples include blowing agents, surface-active substances, fillers, nucleating agents, lubricants and mold release agents, dyes and pigments, antioxidants, for example against hydrolysis, light, heat or discoloration, inorganic and / or organic fillers, flame retardants, reinforcing agents and plasticizers, metal deactivators. In a preferred embodiment, component (e) also includes hydrolysis stabilizers such as, for example, polymeric and low-molecular carbodiimides. The thermoplastic polyurethane in the materials according to the invention particularly preferably contains melamine cyanurate, which acts as a flame retardant. Melamine cyanurate is preferably used in an amount between 0.1 and 60% by weight, particularly preferably between 5 and 40% by weight, in particular between 15 and 25% by weight, in each case based on the total weight of the TPU. The thermoplastic polyurethane preferably contains triazole and / or triazole derivative and antioxidants in an amount of 0.1 to 5% by weight, based on the total weight of the thermoplastic polyurethane. Substances which inhibit or prevent undesirable oxidative processes in the plastic to be protected are generally suitable as antioxidants. In general, antioxidants are commercially available. Examples of antioxidants are sterically hindered phenols, aromatic amines, thiosynergists, organophosphorus compounds of trivalent phosphorus, and hindered amine light stabilizers. Examples of sterically hindered phenols are found in Plastics Additives Handbook, ^5th edition, H. Zweifel, ed, Hanser Publishers, Munich, 2001 ([1]), and S.98-107 S.116- 121. Examples of aromatic amines can be found in [1] p.107-108. Examples of thiosynergists are given in [1], pp.104-105 and pp.112-113. Examples of phosphites can be found in [1], p.109-112. Examples of hindered amine light stabilizers are given in [1], p.123-136. Phenolic antioxidants are preferably suitable for use in the antioxidant mixture according to the invention. In a preferred embodiment, the antioxidants, in particular the phenolic antioxidants, have a molar mass of greater than 350 g / mol, particularly preferably greater than 700 g / mol and a maximum molar mass of <10,000 g / mol, preferably <3000 g / mol. Furthermore, they preferably have a melting point of less than 180 ° C. Antioxidants which are amorphous or liquid are also preferably used. Mixtures of two or more antioxidants can also be used as component (i).

In addition to the above-mentioned components a), b) and c) and optionally d) and e), chain regulators, usually with a molecular weight of 31 to 3000, be used. Such chain regulators are compounds which have only one functional group which is reactive toward isocyanates, such as, for. B. monofunctional alcohols, monofunctional amines and / or monofunctional polyols. With such chain regulators, a flow behavior, in particular with TPUs, can be specifically set. Chain regulators can generally be used in an amount of 0 to 5, preferably 0.1 to 1, part by weight, based on 100 parts by weight of component b), and by definition fall under component (c).

All molecular weights mentioned in this document have the unit [g / mol].

To adjust the hardness of the TPUs, the structural components (b) and (c) can be varied in relatively wide molar ratios. Molar ratios of component (b) to chain extenders (c) to be used in total from 10: 1 to 1:10, in particular from 1: 1 to 1: 4, have proven successful, the hardness of the TPU increasing with increasing content of (c).

The TPU can be produced continuously using the known processes, for example using reaction extruders or the belt process using one-shot or the prepolymer process, or batchwise using the known prepolymer process. In these processes, the components (a), (b), (c) and optionally (d) and / or (e) coming into the reaction can be mixed with one another in succession or simultaneously, the reaction commencing immediately.

In the extruder process, the structural components (a), (b), (c) and, if appropriate, (d) and / or (e) are introduced into the extruder individually or as a mixture, e.g. at temperatures of 100 to 280 ° C, preferably 140 to 250 ° C, and reacted. The TPU obtained is usually extruded, cooled and granulated. After the synthesis, the TPU can optionally be modified by assembly on an extruder. With this assembly, the TPU can e.g. be modified in its melt index or its granulate form according to the requirements.

The processing of the TPUs produced according to the invention, which are usually present in the form of granules or in powder form, into injection molding and extrusion articles, for example the desired films, moldings, rolls, fibers, linings in automobiles, hoses, cable plugs, bellows, trailing cables, cable jackets, seals, belts or damping elements is carried out according to customary methods, such as injection molding or extrusion. Such injection molding and extrusion articles can also be made from compounds containing the TPU according to the invention and at least one further thermoplastic, especially a polyethylene, polypropylene, poly- ester, polyether, polystyrene, PVC, ABS, ASA, SAN, polyacrylonitrile, EVA, PBT, PET, polyoxymethylene. In particular, the TPU produced according to the invention can be used to produce the articles shown at the beginning.

The silane-modified thermoplastic polyurethane will preferably be spun into fibers or hoses, in particular compressed air hoses, by generally known methods, and then the thermoplastic polyurethane will be crosslinked via the silane groups by means of moisture, optionally using a catalyst which accelerates the crosslinking. The crosslinking reactions above and through the silane groups are familiar to the person skilled in the art and are generally known. This crosslinking is usually carried out by moisture and can be carried out by heat or catalysts known for this purpose, e.g. Lewis acids, Lewis bases, Bronsted acids, Bronsted bases are accelerated. Acetic acid, organic metal compounds such as titanium acid esters, iron compounds such as e.g. Iron (III) acetylacetonate, tin compounds e.g. Tin diacetate, tin dioctoate, tin dilaurate or the tin dialkyl salts of aliphatic carboxylic acids such as dibutyl tin diacetate, dibutyl tin dilaurate or the like, particularly preferably tin dilaurate and / or acetic acid.

An important measure for the quality of an elastomer fiber is the heat resistance.

It has surprisingly been found that the heat resistance of the melt-spun fiber which has been crosslinked via silane groups has been significantly improved. For example, a fiber without silane crosslinking according to the invention shows an HDT (heat distortion temperature, measurement under a pretension of 0.04 mN / dtex; heating rate 10 K / min; measuring range from -100 ° C. to 250 ° C.) of 120 ° C. The crosslinking by the silane groups increased the HDT to 173 ° C.

Another advantage of the crosslinking of melt-spun elastomer fibers according to the invention is the improved resistance to conventional spinning preparations. While melt-spun fibers without crosslinking according to the invention in contact with spin finishes are attacked and in some cases completely destroyed at low temperatures (<120 ° C.), crosslinked fibers according to the invention show virtually no damage even at temperatures above 190 ° C.

The inventive thermoplastically processable polyurethane elastomers can be used for extrusion, injection molding, calendar articles and for powder slush processes.

Claims

claims

1. Thermoplastic polyurethane based on polyisocyanates (x), which have at least one silicon-organic group ("silane group").

2. Thermoplastic polyurethane according to claim 1, characterized in that the polyisocyanate (x) containing at least one silane group via two urethane groups bonded with (b) isocyanate-reactive compounds with a molecular weight between 500 and 10,000 and / or with (c) chain extenders with a Molecular weight of 50 to 499 is present in the thermoplastic polyurethane.

3. Thermoplastic polyurethane according to claim 2, characterized in that there are no allophanate groups between the two urethane groups and the silane groups.

4. Process for the production of thermoplastic polyurethane modified with organic silicon compounds, characterized in that polyisocyanates (x) which have at least one organic silicon group (“silane group”) are used in the production of the thermoplastic polyurethane.

5. The method according to claim 4, characterized in that the thermoplastic polyurethane is produced by reacting (x) polyisocyanates which have at least one silane group and optionally isocyanates (a) which have no silane group with (b) with isocyanate-reactive compounds a molecular weight between 500 and 10,000 and (c) chain extenders with a molecular weight of 50 to 499, the ratio of the sum of the isocyanate groups of component (x) and optionally the isocyanate groups of component (a) to the sum of the isocyanate-reactive functions of the components ( b) and (c) is between 0.9: 1 and 1.2: 1.

6. Process for the preparation of thermoplastic polyurethane modified with organic silicon compounds, characterized in that thermoplastic polyurethane is reacted with polyisocyanates (x) which have at least one organic silicon group (“silane group”).

7. The method according to claim 4 or 6, characterized in that the polyisocyanate (x) used is a compound which is obtainable by reacting compounds which have at least three isocyanate groups with silanes which have a function which is reactive toward isocyanates.

8. The method according to claim 7, characterized in that one of the following compounds is used as the compound which has at least three isocyanate groups: isocyanurate, 1, 8-diisocyanato-4- (isocyanatomethyl) octane, 1,6,11 -undecatriisocyanate , 1, 3,6-Hexamethylenetriisocyanat and / or poly-MDI with an average isocyanate functionality of at least 2.5.

9. The method according to claim 4, characterized in that the molar ratio of the isocyanates (a) to the polyisocyanates (x) is between 1: 0.01 and l: 100.

10- Process according to claim 6, characterized in that between 0.001 and 0.2 mol of silane are used for 100 g of thermoplastic polyurethane.

11. The method according to claim 4 or 6, characterized in that the silane-modified thermoplastic polyurethane is spun into fibers or extruded into tubes and then the thermoplastic polyurethane is crosslinked via the silane groups by means of moisture.

12. The method according to claim 11, characterized in that Lewis catalyst and Lewis acids and Bronsted acids and Bronsted bases are used as catalysts for the crosslinking by means of moisture.

13. Thermoplastic polyurethane obtainable by a process according to any one of claims 4 to 12.

14. Cable sheaths, fibers or hoses based on thermoplastic polyurethane obtainable according to one of claims 4 to 12.

15. Fiber based on thermoplastic polyurethane, which is crosslinked via organic silicon groups, in particular siloxane groups.

16. Hoses based on thermoplastic polyurethane which is crosslinked via organosilicon groups, in particular siloxane groups.

17. Cable sheaths based on thermoplastic polyurethane, which is crosslinked via organic silicon groups, in particular siloxane groups.

18. fiber, hose or cable sheathing according to one of claims 15 to 17, characterized in that the crosslinked thermoplastic polyurethane has a Shore A hardness between 85 and 98 and a Vicat temperature according to DIN EN ISO 306 (10N / 120 K / h) greater than 130 ° C.

19. Use of the thermoplastically processable polyurethane elastomers obtainable by a process according to one of claims 4 to 10 for extrusion, injection molding, calendar articles and for powder slush processes.