WO2013030148A1

WO2013030148A1 - Hydrophilic thermoplastic polyurethanes and use thereof in medical equipment

Info

Publication number: WO2013030148A1
Application number: PCT/EP2012/066591
Authority: WO
Inventors: Jürgen Köcher; Henricus Peerlings
Original assignee: Bayer Intellectual Property Gmbh
Priority date: 2011-08-29
Filing date: 2012-08-27
Publication date: 2013-03-07

Abstract

The invention relates to a thermoplastic polyurethane that can be obtained by reacting at least the following components: a polyisocyanate having two isocyanate groups, a polycarbonate having two isocyanate-reactive groups, a chain extender having two isocyanate-reactive groups, and a polyoxyalkylene ether having an isocyanate-reactive group, wherein the ratio of the isocyanate groups of the polyisocyanate a) to the total of the isocyanate-reactive groups of the polycarbonate diol b), of the chain extender c), and of the polyoxyalkylene ether d) is in the range of 0.95 to 1.05:1. The invention further relates to a method for producing the thermoplastic polyurethane according to the invention and to a medical device that comprises a thermoplastic polyurethane according to the invention.

Description

Hydrophilic thermoplastic polyurethanes and their use in medical technology

The present invention relates to a thermoplastic polyurethane obtainable by reacting at least the following components: a polyisocyanate having two isocyanate groups, a polycarbonate having two isocyanate-reactive groups, a chain extender having two isocyanate-reactive groups, a polyoxyalkylene ether having an isocyanate-reactive group Group. Further objects of the invention are a process for the preparation of the thermoplastic polyurethane according to the invention and a medical device comprising a thermoplastic polyurethane according to the invention. Medical devices such as catheters with hydrophilic surfaces offer many advantages. So they are more easily wetted with water, which on the one hand reduces the friction when introduced into the body and on the other hand increases the biocompatibility. Frequently, hydrophilic surfaces are produced by coating with appropriate polymers. However, the coatings in aqueous environment (tissue, blood, urine) may absorb a great deal of water and swell much more than the underlying substrate of the medical device. The different swelling behavior can lead to a separation of coating and substrate, which is associated with considerable medical complications.

To avoid these complications, medical devices such as catheters can be made directly from an elastic, hydrophilic material. In this case there is no danger of a layer separation. As suitable materials for these purposes, hydrophilic thermoplastic polyurethanes (TPU) have been described. These are usually composed of a long-chain polyether, polyester or polycarbonate diol, a dihydric, short-chain, aliphatic alcohol and an aliphatic or aromatic diisocyanate. A hydrophilic finish is achieved by the use of a hydrophilic polyether diol. Examples of these hydrophilic thermoplastic see polyurethanes are described in the patent applications WO 2007092303, US 2007/0078388, CA 2017951 AI, CA 2017952 AI, US 4,789,720 and WO 8800214 AI. The polyurethanes disclosed herein all comprise polyether diols as building blocks.

However, it has been shown that the polyether-based polyurethanes do not have sufficiently high hydrophilicity. Polyether-based polyurethane ureas are known, for example, from patent application WO 2009 115 263. Even if the compounds described here are chemically stable, they take up comparatively little water, for example about 50% of water, based on the polymer weight. Furthermore, contact angle measurements of the compositions described here result in comparatively high contact angles, so that despite the use a hydrophilic building block the surface of these materials is not sufficiently hydrophilic and therefore poorly wettable.

Further hydrophilic polyether-based TPU resins are known, for example, from the company Lubrizol, Cleveland, OH, under the trade name "Tecophilic." Although many of these materials absorb large amounts of water, for example, they lose up to 1000% of their own weight These hydrogels, due to the high water absorption, have a stability, in particular dimensional stability, which is in part perceived as unfavorable and limits the number of applications of these compounds.

The object of the present invention was therefore to provide a thermoplastic polyurethane for the production of medical devices, which has a higher hydrophilicity than the known TPUs and thereby has good mechanical properties, in particular a high elongation at break and tear strength.

This object is achieved by a polyurethane of the aforementioned type, in which the ratio of the isocyanate groups of the polyisocyanate a) to the sum of the isocyanate-reactive groups of the polycarbonate diol b), the chain extender c) and the polyoxyalkylene ether d) in the range 0, 95 to 1.05: 1.

In other words, the ratio of a: (b + c + d) = 0.95 to 1.05: 1, where a, b, c and d for the respective starting materials a), b), c) and d) stand.

According to the invention, it is provided that the polycarbonate has two isocyanate-reactive groups. This is advantageous in that it makes it possible to obtain a linear polyurethane polymer which has the thermoplastic properties according to the invention.

It is possible to use both aqueous dispersions, organic solutions and LC casting mixtures as well as other formulations known to the person skilled in the art for the preparation.

The individual components for the synthesis of the polyurethane according to the invention are explained in more detail below: a) polyisocyanate having two isocyanate groups

As polyisocyanates a) it is possible to use all aromatic, araliphatic, aliphatic and cycloaliphatic isocyanates known to those skilled in the art having an average NCO functionality of 2 individually or in any mixtures with one another, it being immaterial whether these were prepared by phosgene or phosgene-free processes. These can also iminooxadiazinedione, Isocyanurate, uretdione, urethane, allophanate, biuret, urea, Oxadiazintrion, oxazolidinone, acylurea and / or carbodiimide structures have. The polyisocyanates can be used individually or in any mixtures with one another.

Preference is given to using isocyanates from the series of aliphatic or cycloaliphatic representatives, these having a carbon skeleton (without the NCO groups present) of 3 to 30, preferably 4 to 20, carbon atoms.

Particularly preferred compounds of component (a) correspond to the abovementioned type with aliphatically and / or cycloaliphatically bonded NCO groups, for example bis (isocyanatoalkyl) ethers, bis (isocyanatoalkyl) benzenes, -toluenes, and also -xylols, propane diisocyanates, butane diisocyanates, Pentane diisocyanates, hexane diisocyanates (for example hexamethylene diisocyanate, HDI), heptane diisocyanates, octane diisocyanates, nonane diisocyanates (for example trimethyl-HDI (TMDI) generally as a mixture of 2,4,4- and 2,2,4-isomers), decane diisocyanates, decane triisocyanates, and the like alkane diisocyanates, undecane diisocyanates, dodecane diisocyanates, 1,3- and 1,4-bis (isocyanatomethyl) cyclohexanes (HfrXDI), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), bis (4-isocyanatocyclohexyl) methane (H ₁₂ MDI) or bis (isocyanatomethyl) norbornane (NBDI).

Very particularly preferred compounds of component (a) are hexamethylene diisocyanate (HDI), trimethyl-HDI (TMDI), 2-methylpentane-l, 5-diisocyanate (MPDI), isophorone diisocyanate (IPDI), 1,3- and 1,4-bis (isocyanatomethyl) cyclohexane (H _east XDI), bis (isocyanatomethyl) norbornane (NBDI), 3 (4) -isocyanatomethyl-l-methyl-cyclohexyl isocyanate (IMCI) and / or 4,4'-bis- (isocyanatocyclohexyl) methane (H ₁₂ MDI) or mixtures of these isocyanates. b) polycarbonate with two isocyanate-reactive groups

The polyurethaneurea according to the invention comprises units which are based on at least one polycarbonate carrying hydroxyl groups (polycarbonate polyol). Basically suitable for introducing units based on the hydroxyl-containing polycarbonate are polycarbonate polyols, ie polyhydroxy compounds having an average hydroxyl functionality of from 1.7 to 2.3, preferably from 1.8 to 2.2, more preferably from 1.9 to 2.1, most preferably from about 2.0. The polycarbonate is thus preferably substantially linear. Suitable polycarbonates containing hydroxyl groups are polycarbonates of molecular weight (molecular weight determined by the OH number, DIN 53240) of preferably 400 to 6000 g / mol, more preferably 500 to 5000 g / mol, in particular 600 to 3000 g / mol for example, by reaction of carbonic acid derivatives, such as diphenyl carbonate, dimethyl carbonate or phosgene, with polyols, preferably diols. Examples of such diols are ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bishydroxymethylcyclohexane, 2 Methyl-l, 3-propanediol, 2,2,4-trimethylpentane-l, 3-diol, di-, tri- or tetraethylene glycol, dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols, bisphenol A, tetrabromobisphenol A but also lactone-modified diols in question.

Preferably, the diol component contains from 40 to 100% by weight of hexanediol, preferably 1,6-hexanediol and / or hexanediol derivatives, preferably those having, in addition to terminal OH groups, ether or ester groups, e.g. Products obtained by reacting 1 mole of hexanediol with at least 1 mole, preferably 1 to 2 moles of caprolactone or by etherification of hexanediol with itself to di- or Trihexylenglykol. Polyether-polycarbonate diols can also be used. The hydroxyl polycarbonates should be substantially linear. Preference is given to such polycarbonates based on hexanediol-1, 6, as well as modifying co-diols such. B. Bu- tandiol-1, 4 or ε-caprolactone. Further preferred polycarbonate diols are those based on mixtures of hexanediol-1, 6 and butanediol-1, 4. c) chain extender with two isocyanate-reactive groups

The polyurethaneurea according to the invention has units which are based on at least one diamine or an amino alcohol or on a diol. For the preparation of the thermoplastic polyurethanes according to the invention so-called chain extenders (c) are used. Such chain extenders are diamines as well as hydrazides, e.g. Hydrazine, 1,2-ethylenediamine, 1,2- and 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, isophoronediamine, isomer mixture of 2,2,4- and 2,4, 4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylenetriamine, 1, 3- and 1, 4-xylylenediamine, α, α, α ', α'-tetramethyl-1, 3- and -1,4-xylylenediamine and 4,4-diaminodicyclohexylmethane , Dimethylethylenediamine, hydrazine, adipic dihydrazide, 1,4-bis (aminomethyl) cyclohexane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane and other (Ci-C i) di- and Tetraalkyldicyclohexylmethane, eg 4,4'-diamino-3,5-diethyl-3 ', 5'-diisopropyldicyclohexylmethane.

As diamines or amino alcohols are generally also low molecular weight diamines or amino alcohols into consideration, containing active hydrogen with respect to NCO groups of different reactivity, such as compounds which in addition to a primary amino group also secondary amino groups or in addition to an amino group (primary or secondary) also OH Have groups. Examples of these are primary and secondary amines, such as 3-amino-1-methylaminopropane, 3-amino 1-ethylaminopropane, 3-amino-1-cyclohexylaminopropane, 3-amino-1-methylaminobutane, furthermore amino alcohols, such as N-aminoethylethanolamine, ethanolamine, 3-aminopropanol, neopentanolamine and particularly preferably diethanolamine.

Furthermore, as chain extenders c) diols can be used. The molecular weight is preferably 62 to 500 g / mol, particularly preferably 62 to 400 g / mol, in particular 62 to 200 g / mol.

Suitable polyols may contain aliphatic, alicyclic or aromatic groups. Mention may be made, for example, of the low molecular weight polyols having up to about 20 carbon atoms per molecule, such as e.g. Ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butylene glycol, cyclohexanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, neopentyl glycol, hydroquinone dihydroxyethyl ether, Bisphenol A (2,2-bis (4-hydroxyphenyl) propane) and hydrogenated bisphenol A (2,2-bis (4-hydroxycyclohexyl) propane). Also, ester diols such as e.g. α-hydroxybutyl-s-hydroxy-caproic acid esters, ro-hydroxyhexyl-γ-hydroxybutyric acid esters, adipic acid (β-hydroxyethyl) esters or terephthalic acid bis (β-hydroxyethyl) esters may be used. d) polyoxyalkylene ethers having an isocyanate-reactive group

The polyurethaneurea of the present invention has units derived from a copolymer of polyethylene oxide and polypropylene oxide. These copolymer units are present as end groups in the polyurethaneurea.

Nonionically hydrophilizing compounds (d) are, for example, monovalent polyalkylene oxide polyether alcohols having a statistical average of 5 to 70, preferably 7 to 55, ethylene oxide units per molecule, as are obtainable in a conventional manner by alkoxylation of suitable starter molecules (eg in Ullmanns Enzyklopädie der Technical Chemistry, 4th Edition, Volume 19, Verlag Chemie, Weinheim pp. 31-38).

Suitable starter molecules are, for example, saturated monoalcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, the isomeric pentanols, hexanols, octanols and nonanols, n-decanol, n-dodecanol, n-tetradecanol , n-hexadecanol, n-octadecanol, cyclohexanol, the isomeric methylcyclohexanols or hydroxymethylcyclohexane, 3-ethyl-3-hydroxymethyloxetane or tetrahydrofurfuryl alcohol, diethylene glycol monoalkyl ethers, such as, for example, diethylene glycol monobutyl ether, unsaturated alcohols, such as allyl alcohol, 1,1-dimethylallyl alcohol or oleic alcohol, aromatic alcohols such as phenol, the isomeric cresols or methoxyphenols, araliphatic alcohols such as benzyl alcohol, anisalcohol or cinnamyl alcohol, secondary monoamines such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutyla- min, bis (2-ethylhexyl) amine, N-methyl and N-ethylcyclohexylamine or dicyclohexylamine, and heterocyclic secondary amines such as morpholine, pyrrolidine, piperidine or IH-pyrazole. Preferred starter molecules are saturated monoalcohols. Particular preference is given to using diethylene glycol monobutyl ether as starter molecule. The alkylene oxides ethylene oxide and propylene oxide can be used in any order or even as a mixture in the alkoxylation reaction.

The polyalkylene oxide polyether alcohols are mixed polyalkylene oxide polyethers of ethylene oxide and propylene oxide, the alkylene oxide units of which preferably consist of at least 30 mol%, more preferably at least 40 mol%, of ethylene oxide units. Preferred nonionic compounds are monofunctional mixed polyalkylene oxide polyethers having at least 40 mole percent ethylene oxide and at most 60 mole percent propylene oxide units.

The average molecular weight of the polyoxyalkylene ether is preferably 500 g / mol to 5000 g / mol, particularly preferably 1000 g / mol to 4000 g / mol, in particular 1000 to 3000 g / mol.

In addition to the abovementioned substances, according to the invention it can also be provided that to a lesser extent tri- or higher-functional raw materials a), b) and / or c) are used. However, the amounts to be adjusted so that even a thermoplastic processing of the material is possible.

To the stoichiometry of the reactions:

The quotient of the equivalents of the isocyanate groups used and the sum of the equiva- lents of all isocyanate-reactive groups (NEh, OH) used should be between 0.95 and 1.05. If one deviates from these conditions, one obtains products which can no longer be processed thermoplastically, which is demonstrated in the example section by means of comparative examples.

The ratios of the isocyanate-reactive components are as follows:

0.01-0.05 mol of polyoxyalkylene ether d) per mole of polycarbonate diol a), preferably 0.03-0.4 mole of polyoxyalkylene ether d) per mole of polycarbonate diol a), very particularly preferably 0.05-0.25 mole polyoxyalkylene ether d) per mol of polycarbonate diol a),

0.2-4.0 mol of chain extender c) per mol of polycarbonate diol b), preferably 0.5-3.0 mol of chain extender c) per mol of polycarbonate diol b), very particularly preferably 0.8-2.5 mol of chain extender c ) per mole of polycarbonate diol b). The structure of the thermoplastic polyurethane elastomers can be done in various ways. For example, diol-extended materials can be made by the so-called "one-shot" process, whereby all components in the melt are mixed and reacted with each other from the macrodiol, the monofunctional polyether alcohol and the isocyanate component, a pre-adduct is formed, which is reacted in a second stage with the chain extender to the polyurethane.

The reaction of aliphatic amines proceeds so rapidly even at room temperature that a homogeneous reaction in the melt is no longer possible because of the immediate precipitation of urea. Such polyurethane ureas are preferably prepared in organic solution, as described in DE 31 34 112 AI, the disclosure of which is hereby incorporated into the present application. The polycarbonate diol b) and the polyoxyalkylene ether d) are first reacted with the isocyanate component a) to form a prepolymer, which is then dissolved in an organic solvent such as, for example, toluene and alcohol. The structure of the polymer is then carried out by reaction with the dissolved in an organic solvent such as an alcohol chain extender c). This procedure is particularly suitable for selected from diamines chain extender c). The polyurethane can then be recovered by removal of the solvent, for example by drying and then further processed, for example by extrusion or injection molding. However, the preparation of the polymers of the invention is not limited to the aforementioned methods. Thus, the polymers can also be produced continuously by a belt process, as described in GB 1 057 018, and an extrusion process, as disclosed, for example, in DE 19 64 834 A1. In the case of the production of polyurethane ureas, the process described in DE 24 23 764 A1 is particularly suitable. In addition, the novel polyurethanes can also be prepared as a dispersion, in particular via the acetone process known per se.

To accelerate the reaction rate, one or more catalysts can be added to the reactant mixture expediently. This is especially true for the use of diols as chain extenders c). Suitable catalysts are the tertiary amines known and customary in the prior art, for example triethylamine, dimethylcyclohexylamine, N-methylmorpholine, Ν, Ν'-dimethylpiperazine, 2- (dimethylaminoethoxy) ethanol, diazabicyclo [2.2 , 2] octane and the like, and in particular organic metal compounds such as titanic acid esters, bismuth compounds, iron compounds or tin compounds, such as tin diacetate, tin dioctoate, tin dilaurate or the tin dialkyl salts of aliphatic carboxylic acids, such as dibutyltin diacetate or Dibutyltin dilaurate or the like. Preferred catalysts are organic metal compounds, in particular titanic acid esters, iron, tin, zirconium and bismuth compounds. The total amount of catalysts in the TPU according to the invention is generally preferably 0 to 5 wt .-%, preferably 0 to 2 wt .-%, based on the total amount of TPU. In the case of using diamines as chain extenders c) can be dispensed with the use of a catalyst.

The polyurethanes and polyurethane ureas according to the invention may be used, preferably 0.1-3% by weight (based on the total amount of all components), of waxes, antioxidants, release agents and / or UV absorbers. If a subsequent use of the polymers according to the invention is intended in the medical field, only minimal necessary amounts of such additives should be used, if at all, so that the cell compatibility is not impaired.

As antioxidants, all products known for this purpose, as z. As described in EP-A 12 343 are used. Preferably, antioxidants are those based on sterically hindered phenols, such as. As 2,6-di-t-butyl-4-methyphenol and derivatives (commercial products of the Irganox series, BASF).

In the preparation of the thermoplastic polyurethanes according to the invention, it is possible in principle to add customary antistatics, flame retardants, fillers and colorants. In the case of a medical application of the polymer, however, should be dispensed with the use of these additives.

In order to improve the processability of the polyurethane according to the invention in an extruder, one or more release agents may be added to the polyurethane according to the invention. Particularly preferred for this purpose is the use of Licowachs E Clariant.

Examples

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

methods:

Tear strength: Tear strength was determined according to standard EN ISO 527-3 using a Type 5 specimen with a thickness of 2 mm at a tensile speed of 200 mm / min.

Solution Viscosity (LV):

To measure the solution viscosity, 99.7 g of N-methyl-2-pyrrolidone were weighed with 0.1% dibutylamine and 0.4 g of the respective TPU granules. The samples thus prepared were stirred on a magnetic stirrer. TPU samples were dissolved at room temperature and allowed to stand overnight. The samples and a blank (pure solvent) were measured at 25 ° C at a viscosity measuring the Fa. Schott. The Schott Viscosity Tester consists of: Viscosity tester AVS 400, ASV / S measuring stand, glass thermostat, Ubbelohde viscometer type 50110. The relative solution viscosity is calculated from the time (solution) divided by the time (solvent).

MVR value:

The MVR value of the granules was measured according to ISO 1133 with 10 kg weight. NCO content:

The NCO content of the resins described in the Examples and Comparative Examples was determined by titration in accordance with DIN EN ISO 11909.

Mean particle size:

The determination of the average particle sizes of the polyurethane dispersions is carried out with the aid of a laserdiffratometer "High Performance Particle Sizer HPPS", type HPP 5002 from Malvern Instruments GmbH, Herrenberg, Germany For the measurement, the sample was firstly strongly diluted in the form of an aqueous dispersion about 1 μΐ aqueous dispersion dispersed in 1 ml of water and fed the thus diluted dispersion of the measurement. Solids content:

The solids contents were determined in accordance with DIN-EN ISO 3251. 1 g of polyurethane dispersion was dried at 115 ° C. to constant weight (15-20 min) using an infrared drier. Production of press plates:

To produce press plates from the polymer according to the invention, a dispersion of the polymer was first dried and then granulated. This granulate was then transferred to a heatable hydraulic press "Polystat 200 T" from Servitec Maschinenservice GmbH, Wustermark, DE, wherein the granules were melted at 230 ° C for 5 min without pressure and then pressed for 5 min at 230 ° C and 200 bar. Thereafter, while maintaining the pressure was cooled to below 100 ° C.

Contact Angle Measurement

On the surface of the dried polymer dispersions or on the surfaces of the corresponding press plates measurements of static water edge angle were performed. Initially, any static charge was removed from the sample surface by means of an antistatic hair dryer. Then 10 drops of Millipore water were placed on the surfaces by means of a video edge angle measuring device OCA20 from Dataphysics with computer-controlled syringes and the static wetting edge angle was measured.

List of substances used:

Desmophen C2200: polycarbonate polyol, OH number 56 mg KOH / g, number average molecular weight 2000 g / mol (Bayer MaterialScience AG, Leverkusen, DE)

Polyether PW 56: polyethylene glycol, OH number 56 mg KOH / g, number average molecular weight 2000 g / mol (Bayer MaterialScience AG, Leverkusen, DE)

Polyether LB 25: (monofunctional polyether based on ethylene oxide / propylene oxide number-average molecular weight 2250 g / mol, OH number 25 mg KOH / g (Bayer MaterialScience AG, Leverkusen, DE)

definitions:

In this case, the ratio of the isocyanate groups of the polyisocyanate a) to the sum of the isocyanate-reactive groups of the polycarbonate diol b), of the chain extender c) and of the polyoxyalkylene ether d) is considered to be the ratio, in other words the ratio of a: (b + c + d)

Examples 1-4: Products with diols as chain extenders

Example 1 (inventive)

488.5 g of the polycarbonate diol Desmophen C 2200, 75.0 g of the polyether LB 25, 49.3 g of cyclohexanedimethanol were initially charged at 130 ° C. and 139.0 g of isophorone diisocyanate were added. The reaction mixture was heated to 150 ° C and stirred at this temperature. After 10 minutes, the maximum possible viscosity was reached and the batch was poured into an aluminum pan preheated to 80 ° C. The product was then stored for 2 h at 90 ° C. Subsequently, the material was granulated.

The key figure is 1.04. Example 2 (comparison)

Compared to Inventive Example 1, this endcapping product of the polymer chain contains the short-chain butylglycol instead of the long-chain polyether LB 25. The short-chain monoether component formed during installation leads to an overall less hydrophilic polymer compared to Example 1. 977 g of the polycarbonate diol Desmophen C 2200, 7.9 g of butylglycol, 98.6 g of cyclohexanedimethanol were initially introduced at 130.degree. C. and 278.0 g of isophorone diisocyanate were added. The reaction mixture was heated to 150 ° C and stirred at this temperature. After 20 minutes, the maximum possible viscosity was reached and the batch was poured into an aluminum pan preheated to 80 ° C. The product was then stored for 2 h at 90 ° C. Subsequently, the material was granulated.

The key figure is 1.04. Example 3 (equal)

In comparison to Inventive Example 1, this end product contains the hydrophobic 1-octanol. A part of the polycarbonate diol Desmophen C 2200 was replaced by the hydrophilic polyether PW 56. As a result of this partial replacement of Desmophen C 2200 by the polyether PW 56, the overall hydrophilicity of the resulting polymer is increased, the hydrophilicity only increasing overall, but not in the end group. This experiment thus shows the influence of the hydrophilicity of the end group in comparison to Example 1.

841.2 g of the polycarbonate diol Desmophen C 2200, 136 g of the polyether diol PW 56, 8.6 g of 1-octanol, 98.6 g of cyclohexanedimethanol were initially charged at 130 ° C. and 278.0 g of isophorone diisobutoxide were added. added cyanate. The reaction mixture was heated to 150 ° C and stirred at this temperature. After 35 minutes, the maximum possible viscosity was reached and the batch was poured into an aluminum pan preheated to 80 ° C. The product was then stored for 2 h at 90 ° C. Subsequently, the material was granulated. The key figure is 1.01.

In the following Table 1, the compositions of Examples 1 -3 and the resulting key figures are summarized again:

Table 1: Summary of stoichiometry of Experimental Examples 1 -3

Example 4: Physical Characterization

Of the granules of Examples 1 -3 pressed plates were prepared according to the method described above prepared and examined for its physical and mechanical properties. The following Table 2 summarizes the test results:

Table 2: Physical properties of the thermoplastic polyurethanes of Examples 1-3 As Table 2 illustrates, the physical properties of the inventive product are equal to the properties of the two comparative products. However, the inventive product of Example 1 shows a relatively low water edge angle, is thus much better wasserbe- wettable than the comparison products. The interpretation of the results also shows that the end group must be a longer polyether group incorporated in the molecule. Butyl glycol can be considered as a short-chain polyether block. Here, the water edge angle is much higher.

In example 3, a hydrophobic end group in the polyurethane was used with 1-octanol. Hydrophilia was adjusted by replacing part of the Desmophan C 2200 with the hydrophilic polyether diol PW 56. Due to the diol structure of this hydrophilic product is incorporated into the polymer chain, while the material according to the invention contains the hydrophilic polyether as an end group. The comparison of the water edge angles clearly shows that the incorporation of the hydrophilic group into the polymer chain as in Example 3 has no positive effect on the water edge angle. Example 1 clearly shows that only the inventive material with a hydrophilic polyether as the end group is readily wettable due to the low water edge angle.

Examples 5-8: Products with Diamines as Chain Extender Example 5 (Inventive)

488.5 g Desmophen C 2200, 75.0 g LB 25 and 139.5 g isophorone diisocyanate (IPDI) were reacted at 110 ° C to a constant NCO content of 4.2%. It was allowed to cool and diluted with 875.0 g of toluene and 500 g of iso-propanol. At room temperature, a solution of 58.1 g of isophoronediamine in 263.0 g of 1-methoxy-2-propanol was added. After completion of the molecular weight build-up, which could be recognized by the end of the viscosity buildup of the batch, stirring was continued for a further 20 hours to block the remaining free isocyanate groups with iso-propanol. 2399.1 g of a 32.2% strength polyurethaneurea solution in toluene / isopropanol / 1-methoxypropanol-2 having a viscosity of 48200 mPas at 23 ° C. were obtained. 2000 g of the resulting solution were poured into aluminum dishes and dried, then the resulting polyurethane granulated.

The key figure is 1.04. Example 6 (comparison)

Compared to Inventive Example 5, this endcapping product of the polymer chain contains the short-chain butylglycol instead of the long-chain polyether LB 25. The short-chain monoether building block formed during installation leads to an overall less hydrophilic polymer compared to Example 5.

488.5 g of Desmophen C 2200, 4 g of butylglycol and 139.0 g of isophorone diisocyanate (IPDI) were reacted at 110 ° C to a constant NCO content of 4.7%. It was allowed to cool and diluted with 875.0 g of toluene and 500 g of iso-propanol. At room temperature, a solution of 58.1 g of isophoronediamine in 263.0 g of 1-methoxy-2-propanol was added. After completion of the molecular weight and reaching the desired viscosity range, stirring was continued for a further 20 hours in order to block the remaining free isocyanate groups with isopropanol. This gave 2327.6 g of a 30.1% polyurethaneurea solution in toluene / iso-propanol / 1-methoxy-2-propanol having a viscosity of 16,800 mPas at 23 ° C. 2000 g of the resulting solution were poured into aluminum dishes and dried, then the resulting polyurethane granulated.

The key figure is 1.01.

Example 7 (equal)

Compared to Inventive Example 5, this end product contains the hydrophobic 1-octanol. A part of the polycarbonate diol Desmophen C 2200 was replaced by the hydrophilic polyether PW 56. As a result of this partial replacement of Desmophen C 2200 by the polyether PW 56, the overall hydrophilicity of the resulting polymer is increased, the hydrophilicity only increasing overall, but not in the end group. This experiment thus shows the influence of the hydrophilicity of the end group compared to Example 5. 420.6 g Desmophen C 2200, 68.0 g of polyether PW 56, 4.3 g of 1-octanol and 139.0 g of isophorone diisocyanate (IPDI) were at 110 ° C reacted to a constant NCO content of 4.8%. It was allowed to cool and diluted with 875.0 g of toluene and 500 g of iso-propanol. At room temperature, a solution of 58.1 g of isophoronediamine in 263.0 g of 1-methoxy-2-propanol was added. After completion of the molecular weight and reaching the desired viscosity range, stirring was continued for a further 20 hours in order to block the remaining free isocyanate groups with isopropanol. This gave 2328.0 g of a 30.0% polyurethaneurea solution in toluene / iso-propanol / 1-methoxy-2-propanol having a viscosity of 680 mPas at 23 ° C. 2000 g of the resulting solution were poured into aluminum dishes and dried, then granulated the resulting polyurethane.

The key figure is l, 04. In the following Table 3, the compositions of Examples 5-7 and the resulting figures are summarized again:

Table 3: Summary of Stoichiometry of Experimental Examples 5-7

Example 8: Physical Characterization Of the granules of Examples 5-7, press plates were prepared according to the method described in the beginning and examined for their physical and mechanical properties. The following Table 4 summarizes the test results:

Table 4: Physical properties of the thermoplastic polyurethanes of Examples 5-7

As Table 4 illustrates, the mechanical properties of the inventive product are equal to the properties of the two comparative products. However, the inventive product of Example 5 shows a relatively low water edge angle and thus is much better water wettable than the comparison products. The evaluation of the results also clarifies that It is advantageous to incorporate as the end group a longer polyether group in the molecule. For example, the butyl glycol, which is to be regarded as a rather short-chain polyether component, results in a polyurethane having a significantly higher water edge angle.

In Example 7, a hydrophobic end group was incorporated into the polyurethane with 1-octanol. The necessary hydrophilicity was set by replacing part of the Desmophens C 2200 with the hydrophilic polyether diol PW 56. Due to its diol structure, this compound is incorporated into the polymer chain, whereas the material according to the invention has hydrophilic polyethers as an end group. The comparison of the water edge angles clearly shows that the incorporation of hydrophilic groups in the polymer chain as in Example 7 has no positive effect on the water edge angle. By contrast, Example 5 demonstrates that the inventive material with a hydrophilic polyether as the end group has a low water edge angle and is therefore readily wettable.

Example 9 (inventive)

488.5 g Desmophen C 2200, 75.0 g LB 25 and 139.5 g isophorone diisocyanate (IPDI) were reacted at 110 ° C to a constant NCO content of 4.3%. It was allowed to cool and diluted with 875.0 g of toluene and 500 g of iso-propanol. At room temperature, a solution of 58.1 g of isophoronediamine in 263.0 g of 1-methoxy-2-propanol was added. After completion of the molecular weight and reaching the desired viscosity range was stirred for a further 5 hours to block the residual isocyanate content with iso-propanol. 2399.1 g of a 32.3% strength polyurethane urea solution in toluene / isopropanol / 1-methoxypropanol-2 having a viscosity of 20400 mPas at 23 ° C. were obtained. 2000 g of the resulting solution were poured into aluminum dishes and dried, then the resulting polyurethane granulated.

The key figure is 1.04.

Example 10: Physical Characterization of the Inventive Material of Example 9 and Comparison with Two Commercial Thermoplastic Polyurethanes

The polyurethane of Example 9 was used to determine the melt viscosity (MVR) and the relative solution viscosity of the granules and of the strand resulting from the investigation of the melt viscosity. In addition, press plates were prepared as described above at 230 ° C to hereby perform tensile tests. As a comparison, the same investigations with the Commercial products Desmopan 6580 A and Impranil ELH of BayerMaterialScience AG. The following Table 5 summarizes the results:

Product Example Desmopan 6580 Impranil ELH 9 A

Solution viscous granules 1,271 1,622 1,259 viscosity

Solution visMVR strand 1,244 1,429 1,259 viscosity

Solution Visible Platen 1.224 1.339 1.233 viscosity

230 ° C

MVR 5 min; 10 kg; 7.79 19.6

(ml / 10 min) 190 ° C

MVR 5 min; 10 kg; 23

(ml / 10 min) 200 ° C

MVR 5 min; 10 kg; 10

(ml / 10 min) 220 ° C

Yield strain (%) Press plate 414 596 351 230 ° C

Tensile strength Press plate 20.4 14.7 30.5

(MPa)

230 ° C

Tension 100% Press Plate 2.94 3.7 8.4

(MPa) 230 ° C

Tension 300% Press plate 11.9 6.4 26.5

(MPa)

230 ° C

Contact angle <10 75 72

Table 5

The investigation results show that the inventive material is thermoplastically processable and that the properties found fall within the range of commercially available thermoplastic polyurethanes. Example 11 (comparison)

277.2 g of Desmophen C 2200, 33.1 g of polyether LB 25 and 6.7 g of neopentyl glycol were initially introduced at 65 ° C. and homogenized by stirring for 5 minutes. 71.3 g of 4,4'-bis (isocyanatocyclohexyl) methane (H ₁₂ MDI) and then 11.9 g of isophorone diisocyanate were first added to this mixture at 65 ° C. within 1 min. It was heated to 1 10 ° C. After 3 h 40 min, the theoretical NCO value was reached. The finished prepolymer was dissolved at 50 ° C in 711 g of acetone and then added at 40 ° C, a solution of 4.8 g of ethylenediamine in 16 g of water within 10 min. The stirring time was 15 min. The mixture was then dispersed within 15 minutes by adding 590 g of water. This was followed by removal of the solvent by distillation in vacuo. A storage-stable polyurethane dispersion with a solids content of 39.1% and an average particle size of 143 nm was obtained. 220 g of the resulting dispersion were poured into aluminum dishes and dried, then granulated the resulting polyurethane.

The key figure is 1.12. Example 12: Physical Characterization of the Material According to Example 11

For the polyurethane of Example 11, the melt viscosity (MVR) and the relative solution viscosity of the granules as well as the strand resulting from the examination of the melt viscosity were determined.

Example MVR Rel. Solution Viscosity Rel. Solution Viscosity

(Granules) (MVR strand)

(190 ° C)

Table 6

The determined value of the solution viscosity proved that an undesirable three-dimensional crosslinking had occurred due to the high index, which resulted from a significant isocyanate group excess. The solution viscosity of the MVR rod had decreased significantly. As a result, this meant that the material of Comparative Example 11 was less suitable for thermoplastic processing.

Trial 13 (comparison)

494.8 g of the polycarbonate diol Desmophen C 2200, 75.0 g of the polyether LB 25, 49.3 g of cyclohexanedimethanol were initially charged at 130 ° C. and 117.0 g of isophorone diisocyanate were added. The reaction mixture was immediately heated to 150 ° C, by the exotherm, the reaction temperature rose to 175 ° C. The mixture was stirred for 1 h at this temperature and poured out the approach to a preheated to 80 ° C aluminum shell. The product was then stored for 2 h at 90 ° C. Pieces of the poured polyurethane were ground in a mill. Due to the chosen Isocyanatunterschusses based on the hydroxyl groups, the material was so soft that it could not be ground. The product began to melt due to the slightly elevated temperatures in the grinder, so that no granulation was achieved.

The key figure is 0.86.

Claims

claims

1. Thermoplastic polyurethane obtainable by reacting at least the following components: a) a polyisocyanate having two isocyanate groups, b) a polycarbonate having two isocyanate-reactive groups, c) a chain extender having two isocyanate-reactive groups, d) a polyoxyalkylene ether having a Isocyanate-reactive group, characterized in that the ratio of the isocyanate groups of the polyisocyanate a) to the sum of the isocyanate-reactive groups of the polycarbonate diol b), the chain extender c) and the polyoxyalkylene ether d) in the range from 0.95 to 1 , 05: 1 lies.

2. Thermoplastic polyurethane according to claim 1, characterized in that the polyisocyanate a) one or more compounds selected from the group of hexamethylene endiisocyanate, trimethylhexamethylene diisocyanate, 2-methylpentane-l, 5-diisocyanate, isophorone diisocyanate, 1,3- and / or 1,4-bis (isocyanatomethyl) cyclohexane, bis (isocyanatomethyl) norbornane, 3 (4) isocyanatomethyl-1-methylcyclohexylisocyanate, 4,4'-bis (isocyanatocyclohexyl) methane or derivatives thereof with uretdione, isocyanurate, Urethane, allophanate, biuret, Iminooxadiazindion- and / or Oxadiazmtrionstruktur with two NCO groups.

3. Thermoplastic polyurethane according to one of claims 1 or 2, characterized in that the polycarbonate b) by reacting at least one carbonic acid derivative in particular selected from the group diphenyl carbonate, dimethyl carbonate, phosgene and a diol selected in particular from the group ethylene glycol, 1,2-propanediol , 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bis-hydroxymethylcyclohexane, 2-methyl-1,3-propanediol, 2 , 2,4-trimethylpentane-l, 3-diol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycols, bisphenol A, tetrabromobisphenol A is available.

4. Thermoplastic polyurethane according to one of claims 1 to 3, characterized in that the polycarbonate b) has a number average molecular weight of 400 to 6000 g / mol, preferably from 500 to 5000 g / mol and particularly preferably from 600 to 3000 g / mol ,

5. Thermoplastic polyurethane according to one of claims 1 to 4, characterized in that the isocyanate-reactive groups of the polycarbonate b) and / or the chain extender c) and / or the polyoxyalkylene ether d) are amino groups and / or hydroxy groups.

6. Thermoplastic polyurethane according to one of claims 1 to 5, characterized in that the chain extender c) one or more compounds selected from the group of hydrazine, ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, isophoronediamine, isomer mixtures of 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylenetriamine, 1,3- and 1,4-xylylenediamine, a, a, a ', a '-Tetramethyl-l, 3- and -1,4-xylylenediamine and 4,4'-diaminodicyclohexylmethane, dimethylethylenediamine, adipic dihydrazide, 1,4-bis (aminomethyl) cyclohexane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane "N-aminoethylethanolamine, ethanolamine, 3-aminopropanol, neopentanolamine, diethanolamine, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butylene glycol, cyclohexanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 1,12-dodecanediol, neopentyl glycol, hydroquinone dihydroxyethyl ether, bisphenol A (2,2-bis (4-hydroxyphenyl) propane), hydrogenated bisphenol A (2,2-bis (4-hydroxycyclohexyl) propane).

7. Thermoplastic polyurethane according to one of claims 1 to 6, characterized in that the monofunctional polyoxyalkylene ether d) comprises ethylene oxide and propylene oxide units.

8. Thermoplastic polyurethane according to claim 7, characterized in that the monofunctional polyoxyalkylene ether d) comprises at least 40 mol% of ethylene oxide and a maximum of 60 mol% of propylene oxide units.

9. Thermoplastic polyurethane according to one of claims 1 to 8, characterized in that the number average molecular weight of the monofunctional polyoxyalkylene ether d) 500 g / mol to 5000 g / mol, preferably 1000 g / mol to 4000 g / mol and more preferably 1000 to 3000 g / mol. Thermoplastic polyurethane according to one of claims 1 to 9, characterized in that in the reaction of components a) to d) additionally a catalyst e) is used.

Thermoplastic polyurethane according to claim 10, characterized in that the catalyst e) is one or more compounds selected from the group of tin-containing, bismuth-containing, iron-containing, zirconium-containing or titanium-containing compounds and the tertiary amines.

A process for preparing a thermoplastic polyurethane according to any one of claims 1 to 11 in which the components a) to d) and optionally e) are mixed directly with each other and optionally to a temperature in the range between 80 and 200 ° C and preferably between 100 and 180 ° C. to be heated.

A process for preparing a thermoplastic polyurethane according to any one of claims 1 to 1 1 in which the components b) and d) are first reacted with the component a) to form a prepolymer, which is then dissolved in an organic solvent, the prepolymer then with the dissolved in an organic solvent component c) is brought to the reaction to obtain the thermoplastic polyurethane, wherein the component c) is in particular a diamine.

Medical device comprising a thermoplastic polyurethane according to one of claims 1 to 11. 15. Medical device according to claim 14, characterized in that it consists of the thermoplastic polyurethane.