WO2003031506A1 - Stabilizer mixture and stabilized polyurethanes - Google Patents

Abstract

The invention relates to a stabilizer mixture containing an antioxidant (i), a HALS compound (ii), an UV absorber (iii) and a phosphorous compound (iv). The invention also relates to polyurethanes containing the above-mentioned stabilizer mixture.

Description

Stabilizer mix and stabilized polyurethanes

description

The invention relates to a stabilizer mixture comprising an antioxidant (i), a HALS compound (ii), a UV absorber (iii) and a phosphorus compound (iv), and the use thereof for stabilizing polyurethanes. The invention further relates to polyurethanes containing the above-mentioned stabilizer mixture.

Polyurethanes, in particular thermoplastic polyurethanes (hereinafter referred to as TPU), are generally stabilized with thermal and UV stabilizers in order to minimize the decrease in mechanical properties and the discoloration of the products due to oxidative damage.

A group of possible UV stabilizers are UV absorbers, which absorb high-energy UV light and dissipate energy. Common UV absorbers that are used in technology include e.g. to the group of cinnamic acid esters, diphenylcyanoacrylates, diarylbutadienes and benzotriazoles.

Another class of UV stabilizers are the sterically hindered amines, also known as hindered amine light stabilizers (HALS). The activity of HALS is based on its ability to form nitroxyl radicals which intervene in the mechanism of the oxidation of polymers. HALS are considered efficient UV stabilizers for most polymers.

In general, the stabilizers described above are used in blends. For example, UV absorbers can be combined with phenolic stabilizers or UV absorbers with HALS compounds, HALS compounds with phenolic stabilizers and also combinations of HALS, UV absorbers and phenolic stabilizers.

US 5824738 describes the use of such a mixture of antioxidant, UV absorber and HALS for stabilizing thermoplastic polyurethane.

However, it has been shown that especially stabilizer mixtures for UV stabilization, which contain a UV absorber component, tend to yellow the polyurethanes to be stabilized before exposure. This yellow Coloring, as little as it may be, is undesirable and leads to rejection of the product.

Another problem with stabilizers is their migration behavior, i.e. e.g. their volatility and their tendency to bloom. With the latter there is visible coating of the stabilizer on the surface of the workpiece. The stabilizer is removed from the workpiece and can no longer work. In addition, such coverings often lead to customer complaints due to the visual impairment of the workpiece. This is a problem especially with thick workpieces with a small surface / volume ratio.

Volatility of the stabilizers, on the other hand, becomes a relevant problem when the surface / volume ratio becomes large. The stabilizers evaporate from the plastic, which is therefore unprotected and damaged by UV light. This so-called "fogging" can be used in special applications e.g. in the interior of automobiles, the volatilizing portion of UV stabilization means that the customer's limit values for the total amount of volatile constituents are exceeded and the plastic is rejected.

Polyurethanes are generally constructed from an isocyanate and a polyol, e.g. a polyetherol or a polyesterol and optionally a chain extender, e.g. a low molecular weight diol. The choice of polyol generally plays a crucial role in the stability of the product. Thus, polyesterols are oxidatively very stable, but tend to hydrolise. This sensitivity to hydrolysis can be increased by the wrong choice of stabilizers. Polyether oils, on the other hand, are hydrolytically stable, but are more sensitive to oxidation. Furthermore, the choice of the hardness of the product also has an influence on the sensitivity to oxidation of the polyurethane. For example, soft polyetherol types are more sensitive to oxidation than hard polyetherol types.

Ultimately, it is important for the manageability of a stabilizer mixture that it can be incorporated in different ways in order to be as flexible as possible; For example, it should be possible to meter in the stabilizer as a concentrate in the manufacture of the finished parts, for example in an injection molding and / or extrusion process, ensuring a homogeneous distribution in the product. It should also be possible to use the individual components of the stabilizer mixture to form the reaction mixture in the production of the polyurethane, for example in a belt process or in a reactive extrusion admit. It is important that the material can be worked in quickly and homogeneously, does not stick in the dosing unit, and does not contain any volatile components that lead to problems in workplace hygiene or safety problems such as explosion protection during processing.

The object of the invention was therefore to provide a stabilizer mixture for polyurethanes, preferably for thermoplastic polyurethanes, which

Yellowing of the TPU when exposed to UV radiation e.g. reduced by sunlight;

• leads to a low initial yellowing of the products;

• Can be used in both polyether and polyester TPU;

• can be used in both hard and soft TPU types;

• can be added to the plastic to be stabilized during synthesis, during processing or as a concentrate, and

• is bloom free and low in fogging.

The object was achieved by a mixture containing an antioxidant, a HALS compound, a UV absorber and a phosphor compound.

The invention thus relates to a stabilizer mixture containing

(I) an antioxidant,

(II) a HALS connection,

(III) a UV absorber and

(IV) a phosphorus compound.

Another object is the use of the stabilizer mixture according to the invention for stabilization, preferably for UV stabilization, of compact and cellular polyurethanes, preferably of thermoplastic polyurethanes.

This invention also relates to polyurethanes, preferably thermoplastic polyurethanes, which contain the stabilizer mixture according to the invention.

Finally, the subject of the invention is a process for the production of the polyurethanes according to the invention and their use for the production of molded articles. Substances which inhibit or prevent undesirable oxidative processes in the plastic to be protected are generally suitable as antioxidants, which are component (i) in the stabilizer mixture. In general, antioxidants are commercially available. Phenolic antioxidants are preferably suitable for use in the stabilizer mixture according to the invention.

In a preferred embodiment, the antioxidants (i), in particular the phenolic antioxidants, have a molar mass of greater than 350 g / mol, particularly preferably greater than 700 g / mol. It is also preferred that the molar mass of the antioxidants (i) is less than 5000 g / mol, particularly preferably less than 1500 g / mol. Furthermore, the antioxidants (i) preferably have a melting point of less than 180 ° C., particularly preferably less than 130 ° C. Furthermore, antioxidants which are amorphous or liquid are particularly preferably used. Mixtures of two or more antioxidants can also be used as component (i).

The above-mentioned boundary conditions with regard to molar mass and melting point ensure that the antioxidant does not evaporate even in the case of large surface / volume ratios and that the antioxidant can be incorporated uniformly and homogeneously into the TPU during the synthesis. Examples of suitable phenolic antioxidants are molecules which contain structure 1 as an active ingredient group.

in the

X and Y independently of one another denote a hydrogen atom, straight-chain, branched or cyclic alkyl radicals having 1 to 12 carbon atoms and

Z is a covalent bond via which the active substance group is connected to the remaining molecule of the antioxidant (i). Those compounds which contain the radical 2 are preferably used as the phenolic antioxidant (i),

where Z is as defined above.

Examples of preferred phenolic antioxidants which contain active ingredient group 1 are triethylene glycol bis (3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate) (Irganox 245, Ciba Specialty Chemicals AG), hexamethylene bis ( 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate) (Irgano 259), pentaerythrityl tetrakis (3- (3, 5-bis (1, 1-dimethylethyl) -4-hydroxyphenyl) propionate 5-di-tert) (Irganox 1010), octadecyl-3- (3, 5-di-tert .butyl- 4-hydroxyphenyl) propionate (Irganox ^® 1076), N, N'-hexamethylene bis- (3, .butyl-4-hydroxy-hydrocinnamic acid amide) (Irganox ^® 1098), phenol, 2,4-dimethyl-6- (l-methylpentadecyl) - + octa-decyl-3- (3,5-di-tert. -butyl- 4-hydroxy-phenyl) propionate (Irganox, ¹ ® 1141), 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) - 4-methylphenyl-acrylate (Irganox ^® 3052) , and CAS no. 125643-61-0 (Irganox ^® 1135).

Particularly preferred phenolic antioxidants are Irgano 1010, Irganox ^® 245, Irganox ^® 259 and stabilizers based on polyetherols.

In particular, particularly preferred antioxidants (i) can be described by the general formulas 3A and 3B.

nι₅n₂,n₃..n_{m 3A} nι ₅ n ₂ , n ₃ ..nm

nι ₅ n ₂ , n ₃ ..n _m

3A

In formulas 3A and 3B, n sind, n, n ₃ ..n _m are integers> 0 and the relationship applies that n = nχ + 1 and n ₃ = n + l and n _{x +} χ = n _x + l, etc ,

The preferred stabilizers 3A and 3B accordingly represent mixtures of different compounds which differ only in the size of n. The proportion of the molecules n, n, n ₃ to n _m is chosen so that the number-average molar mass of the antioxidant mixture corresponds to the molar mass recognized as advantageous. The proportion of the molecules ni, n ₂ , n to n _m is preferably selected such that the number-average molar mass of the stabilizer 3A and / or 3B is greater than 350 g / mol, particularly preferably> 700 g / mol. It is also preferred that the molar mass of the antioxidants (i) is less than 5000 g / mol, particularly preferably less than 1500 g / mol.

In a further preferred embodiment, antioxidant mixtures are used whose polydispersity Pa is greater than 1, ie their number average molecular weight is smaller than their weight average molecular weight. This is generally fulfilled if the antioxidant consists of a mixture of different molecules of structure 3A or 3B with different n. It can be advantageous if not a single phenolic antioxidant is used, but rather mixtures of phenolic antioxidants are used for stabilization. In principle, all phenolic antioxidants which correspond to the molar mass and melting point conditions described above can be used.

Mixtures which contain Irganox 1010 and / or mixtures which contain phenolic antioxidants according to 10 of the general formulas 3A and 3B are particularly preferred.

Alternatively or in addition to compounds according to the general formulas 3A and 3B, 2, 2 ^v -methylene-bis- (4-methyl-6th tert.butyl-phenol), 2, 2 '-isobutylidenes-bis- (4, 6 -dimethyl-15 phenol) and 4,4'-butylidenes-bis- (2-tert. butyl-5-methyl-phenol) can be used as preferred antioxidants (i).

Sterically hindered amines, also called 'hindered amine light stabilizers' (HALS compounds), constitute component (ii) of the

20 stabilizer mixture. The activity of the HALS compounds is based on their ability to form nitroxyl radicals which intervenes in the mechanism of the oxidation of polymers. HALS are considered to be highly efficient UV stabilizers for most polymers. Accordingly, all sterically hindered amines that are in the

25 are able to form nitroxyl radicals as component (ii) of the stabilizer mixture according to the invention. HALS compounds are well known and commercially available.

Oligomeric hindered amine light stabilizers are generally used as hindered amine light stabilizers. Oligomeric hindered amine light stabilizers mean that the molecular weight of the hindered amine light stabilizers is greater than 400 g / mol. Furthermore, the molar mass of the preferred HALS compounds should not be greater than 10000 g / mol, particularly preferably not greater than 35 5000 g / mol.

Preferred HALS compounds (ii) are, for example, those molecules which contain a radical according to general formula 4 as an active ingredient group,

in der X± , X₂/ _{1 2} unabhängig voneinander Wasserstoff, gerad- kettige, verzweigte oder cyclische Alkylreste mit 1 bis 12 Kohlenstoffatomen bedeuten

/, mean straight-chain, branched or cyclic alkyl radicals having 1 to 12 carbon atoms in the X ± X _{2 1 2} are independently hydrogen

and in the Ki a hydrogen atom, an alkyl radical with 1 to 14 carbon atoms, an acyl radical with 2 to 18 carbon atoms, an aryl radical with 6 to 15 carbon atoms, an alkoxy radical with 2 to 19 carbon atoms and an aryloxy-carbonyl radical with 7 to 12 Is carbon atoms

and in which K is a hydrogen atom or a covalent bond via which the active ingredient group 4 is connected to the remaining molecule of the HALS compound.

Examples of oligomeric hindered amine light stabilizers (II) are bis- (2, 2, 6, 6-tetramethylpiperidyl) sebacate, bis- (1,2,2,6,6-pentamethylpiperidyl) sebacate (Tinuvin ^® 765, Ciba Specialty Chemicals Inc. ), n-butyl-3, 5-di-tert. butyl-4-hydroxybenzylmalonic acid bis- (1, 2, 2, 6, 6-penta-methylpiperidyl) ester, the condensation product from l-hydroxyethyl-2, 2 , 6, 6-tetramethyl-4-hydroxypiperidine and succinic acid (Tinuvin ^® 622), the condensation product of N, N '- (2, 2, 6, 6-tetramethylpiperidyl) hexamethylene diamine and 4-tert-octylamino-2, 6 -dichloro-s-triazine, tris- (2, 2,6, 6-tetra-methylpiperidyl) -bis- (3,3,5, 5-tetramethylpiperazinone), bis (1-octyloxy-2, 2,6, 6 -tetramethylpiperidin-4-yl) sebacate, and Uvinul ^® 4050 H.

In a preferred embodiment, mixtures of HALS compounds are used as component (ii). For example, it may be advantageous to mix a HALS with a molecular weight> 2000 g / mol with an HALS with a molecular weight <1000 g / mol.

UV absorbers are used as component (iii) in the stabilizer mixture according to the invention. In general, those UV absorbers which can be considered are compounds which absorb UV light in the UV-A and UV-B region of the spectral range. Such compounds are generally known and commercially available.

In a preferred embodiment, derivatives of diphenylcyanoacrylates, benzotriazoles, benzophenones and / or derivatives of diarylbutadienes are used as UV absorbers (iii). In particular, UV absorbers based on benzotriazoles are used. In a preferred embodiment, the UV absorbers (iii) have a molar mass of greater than 300 g / mol, in particular greater than 390 g / mol. Furthermore, the preferably used UV absorbers (iii) should have a molecular weight of not more than 5000 g / mol, particularly preferably of not more than 2000 g / mol. It is further preferred that the UV absorbers (iii) contain radicals which contain chemical functionalities which can react with isocyanate groups or OH groups. Such residues can be, for example, alcohols, primary and secondary amines, acid groups, ester groups, epoxides.

A UV absorber (iii) based on a

Benzotriazole used. Examples of benzotriazoles are

2- (2 '-hydroxyphenyl) benzotriazoles, e.g. 5'-methyl-, 3 ', 5'-di-tert-butyl-, 5'-tert-butyl-, 5' - (1, 1, 3, 3-tetramethylbutyl) -,

5-chloro-3 ', 5' -di-tert-butyl-, 5-chloro-3 '-tert-butyl-5' -methyl-, 3 '-sec-butyl-5'-tert-butyl-, 4th '-octoxy-, 3', 5 '-di-tert-amyl-, 3', 5'-bis- (α, α'-dimethylbenzyl) -, 3-tert-butyl-5'- (2- (omega -hydroxy-octa- (ethyleneoxy) carbonyl-ethyl) -, 3 '-dodecyl-5' -methyl-, and 3 '-tert-butyl-5' - (2-octyloxycarbonyl) ethyl-, and dodecylated- 5 Examples of particularly suitable benzotriazoles are Tinuvin 213, Tinuvin 328 and Tinuvin ^® 571.

Mixtures of two or more of the UV absorbers (iii) mentioned can preferably also be used as component (iii) of the stabilizer mixture according to the invention.

A phosphorus compound is used as component (iv) in the stabilizer mixture according to the invention. A mixture of two or more phosphorus compounds can also be used.

In a preferred embodiment, organophosphorus compounds of trivalent phosphorus, such as, for example, phosphites and phosphonites, are used as phosphorus compounds. Examples of suitable phosphorus compounds are tri phenyl phosphite, diphenyl alkyl phosphite, phenyl dialkyl phosphite, tris (nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, di-stearyl pentaerythritol diphosphite, tris (2,4-di-tert-butylphenyl) phosphite , Di-isodecyl pentaerythritol diphosphite, di- (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis (2,4- di-tert-butylphenyl) 4,4'-diphenylenediphosphonite, trisisodecyl phosphite Diisodecyl phenyl phosphite and diphenyl isodecyl phosphite or mixtures thereof. The phosphorus compounds are particularly suitable if they are difficult to hydrolyze, since hydrolysis of a phosphorus compound to the corresponding acid can damage the polyurethane, in particular the polyester urethane. Accordingly, the phosphorus compounds which are particularly difficult to hydrolyze are particularly suitable for polyester urethanes. Examples of such phosphorus compounds are dipropylene glycol phenyl phosphite, tri-isodecyl phosphite, triphenyl monodecyl phosphite, trisisononyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tetrakis (2, 4-di-tert- butylphenyl) 4, 4'-diphenylenediphosphonite and di- (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite or mixtures thereof.

In the stabilizer mixture according to the invention, the proportion of components (i) to (iv) is generally not limited. In a preferred embodiment, the antioxidant (i) in an amount of 10 to 50% by weight, particularly preferably 20 to 40% by weight, the HALS compound (ii) in an amount of 10 to 50% by weight. %, particularly preferably from 15 to 40% by weight, of the UV absorber (iii) in an amount of 1 to 50% by weight, particularly preferably from 10 to 25% by weight, and the phosphorus compound (iv) in one Amount of 1 to 50 wt .-%, particularly preferably from 5 to 25 wt .-%, based on the total weight of the stabilizer mixture.

The stabilizer mixture according to the invention can be used to stabilize polyurethanes or to produce stabilized polyurethanes. In general, the use for compact and cellular polyurethanes is possible. The stabilizer mixture according to the invention is preferably used to stabilize elastomeric polyurethane, in particular thermoplastic polyurethane.

Processes for the production of polyurethanes, in particular TPUs, are generally known. For example, polyurethanes, preferably TPUs, can be reacted with (a) isocyanates with (b) isocyanate-reactive compounds with a molecular weight of 500 to 10,000 and optionally (c) chain extenders with a molecular weight of 50 to 499, optionally in the presence of (d) catalysts and / or (e) customary auxiliaries and / or additives are produced.

The starting components and processes for the production of the preferred polyurethanes are to be described by way of example below. Usually used in the manufacture of polyurethanes Components (a), (b) and optionally (c), (d) and / or (e) used are to be described below by way of example:

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, l-isocyanato-3, 3, 5-trimethyl-5- isocyanatomethyl-cyclohexane (isophorone diisocyanate, IPDI), 1, 4- and / or 1, 3-bis (isocyanatomethyl) cyclohexane (HXDI), 1, 4-cyclohexane diisocyanate, l-methyl-2, 4- and / or -2, 6-cyclohexane diisocyanate and / or 4,4'-, 2,4'- and 2,2'-dicyclohexylmethane diisocyanate, 2, 2 ^x -, 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 '-Dirnethyl diphenyl diisocyanate, 1, 2 -Diphenylethane diisocyanate and / or phenylene diisocyanate.

b) As compounds which are reactive towards isocyanates (b), the generally known compounds which are reactive toward isocyanates can be used, for example polyesterols, polyetherols and / or polycarbonate diols, which are usually also summarized under the term "polyols", with molecular weights of 500 to 8000, preferably 600 to 6000, in particular 800 to 4000, and preferably an average functionality of 1.8 to 2.3, preferably 1.9 to 2.2, in particular 2.

c) Generally known aliphatic, araliphatic, aromatic and / or cycloaliphatic compounds with a molecular weight of 50 to 499, preferably 2-functional compounds, can be used as chain extenders (c), for example diamines and / or alkanediols with 2 to 10 carbon atoms in the alkylene radical, in particular butanediol-1, 4, hexanediol-1, 6 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.

d) Suitable catalysts, which in particular the reaction between the NGO groups of the diisocyanates (a) and the

Accelerating hydroxyl groups of the structural components (b) and (c) are those known in the prior art and customary tertiary amines, such as triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N, N'-dimethylpiperazine, 2- (dimethylaminoethoxy) ethanol, diazabicyclo (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 polyhydroxy compound (b).

e) In addition to catalysts (d), customary auxiliaries and / or additives (e) can also be added to the structural components (a) to (σ). For example, blowing agents, surface-active substances, fillers, flame retardants, nucleating agents, oxidation stabilizers, lubricants and mold release agents, dyes and pigments, if appropriate in addition to the stabilizer mixture according to the invention, further stabilizers, e.g. against hydrolysis, light, heat or discoloration, inorganic and / or organic fillers, reinforcing agents and plasticizers. In a preferred embodiment, component (e) also includes hydrolysis stabilizers such as, for example, polymeric and low-molecular carbodiimides.

In addition to the components a) and b) mentioned and optionally c), d) and e), chain regulators, usually with a molecular weight of 31 to 499, can also 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 set in a targeted manner. 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 set the hardness of the TPUs, the build-up components (b) and (c) can be varied in relatively wide molar ratios. Molar ratios of component (b) to chain extenders (c) of to be used overall have proven successful 10: 1 to 1: 10, in particular from 1: 1 to 1: 4, the hardness of the TPU increasing with increasing content of (c).

Chain extenders (c) are also preferably used to produce the TPU.

The conversion can be carried out using conventional key figures, preferably a key figure of 60 to 120, particularly preferably a key figure of 80 to 110. The key figure is defined by the ratio of the total isocyanate groups of component (a) used in the reaction to the groups reactive toward isocyanates, ie the active hydrogens, of components (b) and (c). If the index is 100, there is one active hydrogen atom for one isocyanate group of component (a) ^' , ie one function of components (b) and (c) which is reactive towards isocyanates. With key figures above 100, there are more isocyanate groups than OH groups.

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) and optionally (c), (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) and optionally (c), (d) and / or (e) are introduced into the extruder individually or as a mixture, e.g. reacted at temperatures of 100 to 280 ° C, preferably 140 to 250 ° C, the TPU obtained is extruded, cooled and granulated.

The TPUs produced according to the invention, which are usually in the form of granules or in powder form, are processed into the desired films, moldings, rollers, fibers, claddings in automobiles, hoses, cable connectors, bellows, trailing cables, cable sheathing, seals, belts or damping elements usual methods, such as Injection molding or extrusion.

To stabilize polyurethanes, components (i) to (iv) are introduced into the polyurethane. The stabilized polyurethanes according to the invention contain the stabilizer mixture according to the invention. In a preferred embodiment, the polyurethane to be stabilized generally contains 0.1 to 5% by weight of antioxidant (i), based on the total weight of the polyurethane.

If the TPU to be stabilized is a polyether TPU with a Shore hardness of less than Shore 54 D, the antioxidant (i) is usually used in concentrations of 0.1 to 5% by weight (% by weight), preferably 0.1 to 1% by weight. -%, particularly preferably 0.5 to 1 wt .-%, based on the total weight of the TPU used.

If the TPU to be stabilized is a polyester TPU or a polyether TPU with a Shore hardness greater than or equal to Shore 54 D, the antioxidant (i) is usually used in concentrations of 0.1 to 5% by weight, preferably 0.1 to 1 % By weight, particularly preferably 0.15 to 0.5% by weight, based on the total weight of the TPU.

The HALS compounds (ii) are usually used to stabilize polyurethanes in concentrations of 0.1 to 5% by weight, preferably 0.1 to 3% by weight, particularly preferably 0.1 to 1% by weight, based on the total weight of the polyurethane.

To stabilize polyurethanes, the UV absorbers (iii) are usually used in concentrations of 0.01 to 2% by weight, preferably 0.05 to 1% by weight, particularly preferably 0.15 to 0.25% by weight, based on the total weight of the polyurethane used.

To stabilize polyurethanes, the phosphorus compounds (iv) are usually used in concentrations of from 0.01 to 5% by weight, preferably from 0.02 to 0.5% by weight, particularly preferably from 0.05 to 0.25% by weight , based on the total weight of the polyurethane used.

If the TPU is a polyester TPU, then an anti-hydrolysis agent is preferably added. Preferred hydrolysis protection agents are polymeric and low molecular weight carbodiimides. Hydrolysis protection agents are generally added in a concentration of 0.05 to 5% by weight, preferably 0.2 to 2% by weight, in particular 0.5 to 1% by weight, based on the total weight of the TPU.

Various processes are possible for producing the polyurethanes according to the invention, comprising the four components (i) to (iv) of the stabilizer mixture according to the invention.

The four components (i) to (iv) of the stabilizer mixture can be metered into the raw materials before the synthesis of the polyurethane, preferably if components (i) to (iv) are miscible with the starting materials of the polyurethane. For example, components (i) to (iv) of the polyol component (b) or the isocyanate component (a) can be added. It is also possible for different stabilizer components to be added to different components for the production of the polyurethane. For example, components (i) to (iii) of the polyol component (b) and the stabilizer component (iv) of the isocyanate component (a) can be added.

Stabilizer components (i) to (iv) can also be used during the synthesis of the polyurethanes, e.g. of the TPU. For example, the four stabilizer components (i), (ii), (iii) and (iv) can be metered individually into the educt streams of the reactor or, if the TPU is produced via a reaction extrusion process, directly into the extruder. It is particularly advantageous here if the four active ingredient components can be mixed before metering and then metered in as a finished premix.

Furthermore, the four components (i) to (iv) of the stabilizer mixture according to the invention can only be processed, e.g. be added to the TPU during an extrusion or injection molding process. It is also particularly advantageous here if the four active ingredient components can be mixed before metering and then metered in as a finished premix.

Finally, the four components of the stabilization can also be incorporated in a TPU in high concentration. This concentrate is then granulated and added as an additive during the processing of an unstabilized TPU.

The process according to the invention for the production of stabilized polyurethanes thus comprises the implementation of

a) polyisocyanates with b) compounds with at least two hydrogen atoms reactive towards isocyanates and c) optionally chain extenders, d) optionally catalysts and e) optionally additives,

characterized in that a phenolic antioxidant (i), a HALS compound (ii), a UV absorber (iii) and a phosphorus compound (iv) one or more of components a) to e) or that from the reaction of components a ) to e) resulting polyurethane are added, the addition of the compounds (i) to (iv) can be carried out separately or in a mixture.

The polyurethanes according to the invention, in particular thermoplastic polyurethanes, are preferably used for the production of molded articles, preferably foils, shoe soles, rollers, fibers, linings in automobiles, wiper blades, hoses, cable plugs, bellows, trailing cables, cable jackets, seals, belts or damping elements, where these have the advantages described at the beginning.

The invention is illustrated by the following examples.

Materials and equipment

UV tests were carried out with a QUV device from Q-Panel

Lab Products, equipped with a UVA fluorescent lamp UVA340 with an intensity maximum at 340 µm. UV tests according to DIN 75 202 were carried out with an atlas

C 35A xenon weather ometer.

The yellowness indices were determined with a colorimeter

Hunterlab UltraScan

Irganox ^® and Tinuvin ^® are trade names of Ciba Specialty Chemicals Lampertheim GmbH.

Naugard ^® is a trade name of Uniroyal Chemical.

Uvinul ^® is a trade name of BASF Aktiengesellschaft,

Ludwigshafen.

example 1

1000 grams of a polyesterol (LP 1010, BASF Aktiengesellschaft) were heated to 80 ° C. in a 2-1 tinplate bucket. The stabilizers were then added with stirring. The type and amount of stabilizers are summarized in Table 1.

Then 88 g of 1,4-butanediol were added. After the solution had subsequently been heated to 75 ° C., 500 g of 4.4 ^λ -MDI (methylene diphenyl diisocyanate) were added and the mixture was stirred until the solution was homogeneous. The reaction mass was then poured into a flat dish and annealed at 125 ° C. on a hot plate for 10 minutes. The resulting rind was then tempered in a heating cabinet at 100 ° C for 24 hours. After the mold plates had been granulated, they were processed into 2 mm spray plates on an injection molding machine. The product has a Shore hardness of Shore 85 A. For comparison, tests V1, 1.2, 1.6, 1.11 and 1.13 were carried out which do not contain a stabilizer mixture according to the invention.

Table 1: Overview of the stabilizer content of the test samples. All products additionally contain the hydrolysis protection additive Elastostab H01 ^® (Elastogran GmbH)

Example 2

The spray plates from Example 1 were irradiated in accordance with DIN 75202 or in a QUV test device (UVA fluorescent lamp UVA-340). The yellowness index of the sample was then measured. The results are summarized in Table 2. If the yellowness indices of sample 1.1 (0 sample) and the further comparison samples are compared with those of the samples stabilized according to the invention, the effectiveness of the stabilizer mixtures according to the invention becomes clear.

From the measurement of the yellowness mdex of the samples before exposure, it is also clear that all samples which contain the combination of antioxidant, UV absorber, HALS and phosphite according to the invention show less initial discoloration than samples with the same amount of the same UV absorber that contain only a combination of antioxidant, UV absorber and HALS. Table 2: Results of the exposure of the samples from Example 1

Example 3

800 g of a polyesterol (LP 1010, BASF Aktiengesellschaft) were heated to 80 ° C. in a 2-1 tinplate bucket. The stabilizers were then added with stirring. The type and amount of stabilizers are listed in Table 3. 174 g of 1,4-butanediol were then added. The solution was then heated to 75 ° C. Then 688 g of 4,4 ^, -MDI were added and the mixture was stirred until the solution was homogeneous. The reaction mass was then poured into a flat dish and annealed on a hot plate at 125 ° C. for 10 minutes. This was followed by a 24 hour tempering of the rind at 100 ° C in a heating cabinet. After the mold plates had been granulated, they were processed into 2 mm spray plates on an injection molding machine. The products have a Shore 6OD hardness.

For comparison, tests V 3.1, 3.2, 3.6, 3.11 and 3.13 were carried out which do not contain a stabilizer mixture according to the invention. Table 3: Summary of the stabilizer contents of the samples.

All samples additionally contain the hydrolysis protection additive Elastostab H01 ^® (Elastogran GmbH)

Example 4

The spray plates from Example 3 were irradiated in accordance with DIN 75 202 or in a QUV test device (UVA fluorescent lamp UVA-340). The yellowness index of the sample was then measured. The results are summarized in Table 4. If the yellowness indices of sample 3.1 (0 sample) and those of the other comparison tests are compared with those of the stabilized samples, the effectiveness of the stabilizer mixtures according to the invention becomes clear.

From the measurement of the yellowness mdex of the samples before exposure, it is also clear that all samples which contain the combination of antioxidant, UV absorber, HALS and phosphite according to the invention show less initial discoloration than samples with the same amount of the same UV absorber that contain only a combination of antioxidant, UV absorber and HALS.

Table 4: Summary of the exposure of the samples from Example 3

10

15

Example 5

20

120 g of a polyethylene glycol (Pluriol E 200, BASF Aktiengesellschaft) (MW: 198.58 g / mol; 0.6043 mol) were mixed with 346.3 g of 3- (3,5-di-tert-butyl-4-hydroxyphenyl) methyl propionate (292.4 g / mol; 1.1844 mol) and 1000 ppm potassium methylate in one

Given 25 four-necked flasks. The substances were heated to 145 ° C. under a permanent stream of nitrogen. The resulting methanol was distilled off. Sales were tracked until the feed materials were fully implemented using GPC. The reaction mixture was then cooled to 90 ° C. and 850 ppm

30 phosphoric acid added to the reaction mixture. It was stirred for 30 min, then 3% water (based on the total mixture) is metered to the mixture and stirred for 60 min ^•. The water was then removed under vacuum at 140 ° C. and the stabilizer was freed from the salt crystals formed by filtration. The

^ Stabilizer produced in this way is amorphous and liquid.

Example 6

A mixture was prepared in a ratio of 2: 1: 1: 1 from the stabilizer prepared in Example 5 and also from Tinuvin ^{® 40} 765, Tinuvin ^® 571 and Naugard ^® P.

The individual components were weighed into a screw cap glass and then heated to 80 ° C. After the heating-up phase, the components were mixed homogeneously for 30 seconds using a KPG stirrer. The product obtained in this way was so low-viscosity at 80 ° C. that it was no problem with the corresponding pumps could be promoted. Even after cooling to room temperature, the mixture is optically homogeneous, so that there is no segregation in this system, which is a great technological advantage since the mixture can be metered into the polymer via only one metering unit.

Example 7

250 g of PTHF 1000 (polyether MW: 1000 g / mol, BASF Aktiengesellschaft) were heated to 80 ° C. in a tinplate bucket.

The stabilizer mixture and 31 g of 1,4-butanediol were then added with stirring. After the solution had subsequently been heated to 85 ° C., 150 g of 4,4 ^, -MDI were added and the mixture was stirred until the solution was homogeneous. The reaction mass was then poured into a flat dish, which was then stored on a hot table heated to 125 ° C. for 10 minutes. The casting plate thus obtained was then heated in a heating cabinet at 100 ° C. for 24 h. The rind was then granulated in a mill. The concentrate thus produced can be metered in to stabilize TPU during processing.

Claims

claims 1. Stabilizer mixture containing (I) an antioxidant, (II) a HALS connection, (III) a UV absorber and (IV) phosphorus compound. 2. Stabilizer mixture according to claim 1, characterized in that the antioxidant (i) in an amount of 10 to 50% by weight, the neck compound (ii) in an amount of 10 to 50% by weight, the UV absorber (iii) in an amount of 1 to 50% by weight and the phosphorus compound ( iv) in an amount of 1 to 50% by weight, based on the total weight of the stabilizer mixture. 3. Stabilizer mixture according to claim 1 or 2, characterized in that the antioxidant (i) is a phenolic antioxidant. 4. Stabilizer mixture according to one of claims 1 to 3, characterized in that the HALS compound (ii) is an oligomeric HALS compound with a molecular weight of greater than 400 g / mol. 5. Stabilizer mixture according to one of claims 1 to 4, characterized in that the UV absorber (iii) is a UV absorber based on a benzotriazole. 6. Stabilizer mixture according to one of claims 1 to 5, characterized in that ^' it is in the phosphorus compound (iv) is an organophosphorus compound of trivalent phosphorus. 7. Use of the stabilizer mixture according to one of claims 1 to 6 for the stabilization of polyurethanes. 8. Polyurethanes containing a stabilizer mixture according to one of claims 1 to 6. 9. Polyurethanes according to claim 8, characterized in that the antioxidant (i) in an amount of 0.1 to 5% by weight, the HALS compound (ii) in an amount of 0.1 to 5% by weight. , the UV absorber (iii) in an amount of 0.01 to 2% by weight and the phosphorus compound (iv) in an amount of 0.01 to 5 wt .-%, based on the total weight of the polyurethane. 10. Process for the preparation of stabilized polyurethanes by reacting a) polyisocyanates with b) compounds with at least two hydrogen atoms reactive towards isocyanates and c) optionally chain extenders, d) optionally catalysts and e) optionally additives, characterized in that a phenolic antioxidant (i), a HALS compound (ii), a UV absorber (iii) and a phosphorus compound (iv) one or more of components a) to e) or that from the reaction of components a ) to e) resulting polyurethane are added, the addition of compounds (i) to (iv) can be carried out separately or in a mixture. 11. Use of the polyurethanes according to claim 8 or 9 for the production of foils, shoe soles, rollers, fibers, linings in automobiles, wiper blades, hoses, Cable connectors, bellows, trailing cables, cable jackets, seals, belts or damping elements.