Use of poly(alkylphenolic) resins in thermoplastic polyurethanes

Abstract

The present invention relates to use of poly(alkylphenolic) resins for lowering the melt viscosity of thermoplastic polyurethanes (TPU), and to a composition containing a thermoplastic polyurethane (TPU) and at least one poly(alkylphenolic) resin. The present invention also relates to a process for the preparation of the composition, as defined herein, wherein the poly(alkylphenolic) resin is incorporated into the TPU, in particular to a molten TPU. In particular, the poly(alkylphenolic) resins comprise repeating units of formula (I) wherein i. R1 is a linear or branched alkylene group with 1 to 10 carbon atoms; ii. R2 is, a linear or branched alkyl group with up to 10, e. g. 1 to 10 carbon atoms, in particular, 2 to 8 carbon atoms or 3 to 6 carbon atoms, especially 4 carbon atoms.

Description

[0001] Use of poly(al kyl phenolic) resins in thermoplastic polyurethanes

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to use of poly(a I kyl phenol ic) resins for lowering the melt viscosity of thermoplastic polyurethanes (TPU), and to a composition containing a thermoplastic polyurethane (TPU) and at least one poly (al kyl phenol ic) resin. The present invention also relates to a process for the preparation of the composition, as defined herein, wherein the po I y (a I ky I ph en o I ic) resin is incorporated into the TPU, in particular to a molten TPU.

[0004] BACKGROUND ON THE INVENTION

[0005] Thermoplastic polyurethanes (TPUs) are a class of polyurethane plastics that can be processed by heating at temperatures above their softening temperature, e. g. by thermoforming, injection molding, blow molding, melt blowing, melt coating, calendering etc. TPUs are also useful in 3D printing, including fused filament deposition (FFD) 3D printing, selective laser sintering (SSD) 3D printing and 3D inkjet printing.

[0006] Generally, TPU refer thermoplastic polyurethane elastomers composed of hard and soft polyurethane segments, which are linked together by covalent links so that they actually form block-copolymers. Typically, the hard segments form a crystalline or pseudo-crystalline phases in a matrix formed by the soft segments. The soft segments typically account for the high elasticity level of the TPU whereas the soft segments will impart the elongation characteristics of the TPU. The hard segments of TPUs are obtained by reaction of the diisocyanates with low molecular weight difunctional compounds, so called chain extenders, whereas the soft segments are obtained by reaction of the diisocyanates with, high molecular weight di- or polyfunctional compounds having typically a molecular weight of at least 400 g / mol, e. g. from 400 to 10000 g / mol (number average) and a functionality of at least 1.5, e. g. 1.5 to 3, including polyether polyols, polyesterpolyols, polyetheresterpolyols, polyacrylate polyols and the like.

[0007] Due to their structure, TPUs have many beneficial properties, including good mechanical properties, including high impact resistance, high flexibility at low temperatures, high elasticity and good chemical durability, such as high durability, in particular to chemical degradation, high solvent resistance and high resistance to oil or grease. Apart from that, TPUs possess high transparency and high abrasion resistance. Due to their outstanding properties TPU are used in many technical areas, including, for example in the manufacture of mechanically resilient mouldings, such as automotive instrument panels, caster wheels, drive belts, power tools, footwear, sporting goods, inflatable rafts, fire hoses, and a variety of extruded film, sheet and profile uses. TPU is also a popular material found in flexible outer cases of devices like mobile phones and keyboard protectors. TPU is well known for its applications in wire and cable jacketing, hose and tube, in adhesive and textile coating applications, and as an impact modifier of other polymers. It is also used in high- performance films, such as high impact resistant glass structures.

[0008] An important application of TPUs is their use as melt adhesives. Melt adhesives allow for joining techniques with solvent-free, 100% solids adhesive systems. Melt adhesives are applied in the form of hot melts, which rapidly solidify on cooling thereby building up their adhesive strength. For example, US2011245449A1 discloses melt adhesive on the basis of a TPU obtained from essentially a symmetrical aliphatic diisocyanate and at least one isocyanate-reactive compound comprising hydroxyl and / or amino groups.

[0009] A general disadvantage of TPU is their high melt viscosity and their sensitivity to shear in the molten state. In particular, TPU tend degrade under the conditions of thermoplastic processing because the temperature required for achieving an acceptable low viscosity required for thermal processing is quite high and close or higher than the degradation temperature of TPUs. Moreover, TPUs show large temperature dependence of melt viscosity and a high activation energy of flow. Therefore, TPUs are difficult to process compared to ordinary thermoplastic polymers. For example, during extrusion or calendar molding, resin dripping or deformation is likely to occur immediately after leaving the processing machine, and during inflation film molding the bubble shape may fluctuate. As TPU are thermoplastic, it is principally possible to de-bond the respective bonded articles by heating. This allows to reuse the components without complete decomposition of the respective components. However, as the melt viscosity is high, high debonding temperatures are often required. Therefore, there is a need for additives which lower the melt viscosity of TPU and thus allow for lower processing temperatures.

[0010] Addition of plasticizers to TPU may help in reducing melt viscosity. However, the use of plasticizers may also decrease the melting point and the crystallization rate of the crystalline hard phases of TPU, thereby increasing cycle time in mold processing and hamper processing. Furthermore, tensile strength and modulus may be adversely affected by addition of plasticizer. Finally, plasticizer may bleed out of the finished product, particularly at high ambient temperatures. US 5,977,268 suggests low molecular weight poly(hydroxyl group)-containing resins, namely resins prepared from styrene and 4-hydroxystyrene, poly(vinylphenol) resins, resins based on the copolymerization of terpenes and phenols, such as vinyl aromatic / terpene / phenol terpolymers and co- or terpolymer resins prepared from dicyclopentadiene and phenols as additives for TPU for reducing cycle time in molding processes.

[0011] SUMMARY OF THE INVENTION

[0012] There still remains a need for providing a means for reducing the melt viscosity TPU, in particular for TPUs suitable in adhesive application, thereby allowing for reducing the processing temperature and the adverse impact of shear and high temperature on the quality of the processed TPU.

[0013] Further, in case of application of the TPU composition as hotmelt adhesive, it should be possible to carry out melt adhesive bonding at a low processing temperature. Moreover, it is necessary that the TPU based hotmelt should rapidly build-up a good bonding strength and with a low bubble count, in order thereby to save energy and to allow high productivity, with an exacting requirement imposed on the mechanical strength at the same time.

[0014] Surprisingly, it has now been found that the use of po ly (a I ky I p he no I ic) resins in TPU solves the above mentioned problems. In particular, the poly (al ky I phenol ic) resins lower the melt viscosity of the TPU without imparting other chemical and / or physical properties of TPU composition such as melting temperature and / or mechanical properties. In particular, only small amounts of the poly (al ky Iphenolic) resins are required to achieve a significant lowering of the melt viscosity. Therefore, the addition of poly(al kyl phenolic) resins to TPU enables a reduction of the melt viscosity of the TPU and thus the processing of the TPU at lower processing temperatures compared to TPU composition without poly(al kyl phenol ic) resin. Moreover, the po ly (a I ky I p he no I) resins do not or only insignificantly affect the solidification time of the molten TPU and do not noticeably lower the melting temperature, so that the mechanical properties of the TPU and, when the TPU is used as a hot melt adhesive, the adhesive strength are not significantly affected. In case of application as hotmelt adhesive, the TPU compositions containing the poly (al kyl phenol) resins enable melt adhesive bonding at a lower bonding temperature without imparting the bonding strength and / or delaying the build-up of the bonding strength.

[0015] Therefore, the present invention relates to use of po ly (a I ky I ph en o I ic) resins for lowering the melt viscosity of thermoplastic polyurethanes (TPU). Occasionally, poly(al kylphenolic) resins have been suggested as tackifying additives for polymers, including polyurethanes, e. g. in CN 112536733 and JP 2000 / 230166.

[0016] The invention also relates to a compositions containing

[0017] A) a thermoplastic polyurethane (TPU) and

[0018] B) at least one po ly (a I ky I ph en o I ic) resin as described herein, except for poly(alkylphenolic) formaldehyde resins.

[0019] The present invention also relates to a process for the preparation of the composition, as defined hereinafter, wherein the poly (al kyl phenol ic) resin is incorporated into the TPU, in particular to a molten TPU.

[0020] DETAILED DESCRIPTION OF THE INVENTION

[0021] As used herein, the term "thermoplastic polyurethane" refers to any polyurethane that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.

[0022] Here and throughout the specification, the terms “wt%”, "wt.-%", “wt.%”, “weight percent” and "% by weight" are used synonymously.

[0023] The "molecular weight Mn" or the "molar mass Mn" is the number-average molecular weight or molar mass. The "molecular weight Mw" or the "molar mass Mw" is the mass-average molecular weight or molar mass. If not stated otherwise, the Mn and Mw were determined by GPC with an Rl (refractive index) detector, using a mixture of hexafluoroisopropanol and 0.05% potassium trifluoroacetate as an eluent (temperature: 40°C, flow rate: 1 mL / min) and polymethyl methacrylate of defined molecular weight as standards for calibration.

[0024] As used herein, the term "resin" refers to a solid or liquid synthetic organic polymer used as the basis of plastics, adhesives, varnishes, or other products.

[0025] As used herein, the term po ly (a I ky I ph en o I ic) resin refers to resins comprising alkylphenolic repeating units, e. g. CJ-CJQ alkylphenolic repeating units, in particular C2-C8or C3-C6alkyl phenolic repeating units, especially C4-al kyl phenol ic repeating units, such as tert. -butylphenol repeating units.

[0026] Here, the term alkyl refers to linear or branched saturated hydrocarbon groups having e. g. 1 to 10 carbon atoms (CJ-CJQ alkyl), in particular 2 to 8 carbon atoms (C2-C8alkyl) or 3 to 6 carbon atoms (C3-C6alkyl), especially 4 carbon atoms (C4- alkyl). Examples of alkyl include, methyl, ethyl, n-propyl, 2-propyl, 1-butyl, 2-butyl,

[0027] 2-methyl-l-propyl (isobutyl), 2-methyl-2-propyl (= tert. -butyl), 1-pentyl, 2-pentyl,

[0028] 3-pentyl, 2-methyl-l-butyl, 3-methyl-l-butyl, 2-methyl-2-butyl, 2,2-di methyl propyl , n-hexyl, n-heptyl, n-octyl, 2-octyl, 2-ethy I hexy I , n-nonyl, isononyl, n-decyl etc.

[0029] In the po ly (a I ky I ph en o I ic) resins, the amount of alkylphenolic repeating units are preferably at least 50% by weight, in particular at least 60% by weight, especially at least 70% by weight of the po ly (a I ky I ph en ol ic) resin. I n addition to the alkylphenolic repeating units, the po ly (a I ky I ph en o I ic) resins typically comprise linking units which link the alkylphenolic repeating units. Typical linking units include bivalent hydrocarbon groups having usually 1 to 10 carbon atoms, in particular 1 to 4 carbon atoms and especially 1 or 2 carbon atoms.

[0030] Examples of poly(al kyl phenolic) resins include resole alkylphenolics and novolac alkylphenolics which are obtained by reacting alkyl phenols with aliphatic aldehydes, such as formaldehyde or acetaldehyde.

[0031] In particular, the po ly (a I ky I p he no I ic) resins comprise repeating units of formula (I) wherein i. R1is a linear or branched alkylene group with 1 to 10 carbon atoms or 2 to 10 carbon atoms, in particular 1 to 4 carbon atoms or 2 to 4 carbon atoms, and especially 1, 2 or 3 carbon atoms; ii. R2is, a linear or branched alkyl group with up to 10, e. g. 1 to 10 carbon atoms, in particular, 2 to 8 carbon atoms or 3 to 6 carbon atoms, especially 4 carbon atoms.

[0032] The repeating units of the formula (I) preferably amount to at least 50% by weight, in particular at least 60% by weight, especially at least 70% by weight, of the weight of the po ly (a I ky I ph en o I ic) resin.

[0033] Preferably, R1in formula (I) is a linear or branched alkylene group having 1 to 4 carbon atoms or 2 to 4 carbon atoms. In a particularly preferred group of embodiments of the invention R1in formula (I) is CH2or HC-CH3or H2C-CH2. In a further particular preferred group of embodiments of the invention R1in formula (I) is different from CH2, with R1being in particular linear or branched alkylene group having 2 to 4 carbon atoms, especially HC-CH3or H2C-CH2.

[0034] In particular, R2in formula (I) is a linear or branched alkyl group with 2 to 8 carbon atoms, preferably linear or branched alkyl having 2 to 6 carbon atoms or 3 to 6 carbon atoms, even more preferably a linear or branched alkyl group with 4 to 6 carbon atoms, especially linear or branched alkyl with 4 carbon atoms, particularly tertiary butyl, especially.

[0035] Resins having repeating units (I) with R1= CH2can be obtained by reacting a phenyl compound of formula R2-C6H4-OH with formaldehyde. I n this reaction formaldehyde adds to a carbon atom of R2-C6H4-OH (usually the carbon atom in ortho position to the OH group) followed by reaction of the obtained methylol group with further R2-C6H4-OH under elimination of water. The obtained resin may to some extent be crosslinked as further formaldehyde might add to the less reactive meta position.

[0036] Preferably, the poly (al ky I phenol ic) resin is a formaldehyde-free po ly (a I ky I p he no I ic) resin, which means that the poly (al kyl phenol ic) does not contain detectable amounts of formaldehyde or produces formaldehyde upon storage or elevated temperature. In particular, formaldehyde-free po ly (a I ky I ph en o I ic) resin are those having repeating units of formula (I), where R1is different from CH2, especially where R1is HC-CH3(ethan-l,l-diyl) or H2C-CH2(ethan - 1,2-diy I) . In this regard, resins with R1=HC-CH3or R1=H2C-CH2can be obtained by reacting a phenyl compound of formula R2-p-C6H4-OH with acetylene. In this reaction acetylene adds to a carbon atom of R2-p-C6H4-OH (usually the carbon atom in ortho position to the OH group) followed by reaction of the obtained vinyl group with further R2-C6H4-OH. The obtained resin may to some extent be cross- linked as further acetylene might add to the less reactive meta position.

[0037] In this preferred group of embodiments, the formaldehyde-free po ly (a I ky I p he no I ic) resin typically comprises units of formula (II): wherein R2in formula (II) is as defined herein and especially tertiary butyl. In this preferred group of embodiments, the formaldehyde-free poly (al kyl phenol ic) resin may further comprise units of formulae (III) and / or (IV): wherein R2in formulae (III) and (IV) is as defined herein and especially is tertiary butyl.

[0038] Typically, at least 50% by weight, in particular at least 60% by weight of the units forming the resin are units of the formula (II) while the total amount of units of the formulae (III) and (IV) is not more than 50% by weight, in particular not more than 40% by weight, based on the total weight of the units (II), (III) and (IV).

[0039] End groups of the polymeric molecules of formaldehyde-free poly (al kyl phenol ic) resin may in particular be vinyl groups which result from excess acetylene or tert- butyl-p-hydroxyphenyl groups.

[0040] The resin may comprise further structural elements which are incorporated by using monomers or reactive additives as further starting materials in the reaction.

[0041] Preferably, at least 80% by weight of the starting materials used for the preparation of the resin are R2-p-C6H4-OH (p- indicates that R2and OH are located para of the phenylene group C6H4) and formaldehyde (in case of R1= CH2) or R2-p-C6H4-OH or acetylene (in case of R1= HC-CH3or R1= H2C-CH2or mixtures thereof), except for catalysts. I n particular at least 90%, especially at least 95% by weight of the starting materials used for the preparation of the resin are R2-p-C6H4-OH and formaldehyde (in case of R1= CH2) or R2-C6H4-OH or acetylene (in case of R1= HC-CH3or R1= H2C-CH2or mixtures thereof) , except for catalysts. I n a most preferred embodiment no other starting materials than R2-p-C6H4-OH and formaldehyde (in case of R1= CH2) or R2-p-C6H4-OH and acetylene (in case of R1= HC-CH3or R1= H2C-CH2or mixtures thereof) are used for the preparation of the po ly (a I ky I ph en o I ic) resin, except for catalysts.

[0042] An especial ly preferred poly (al ky I phenol ic) resin is commercially obtainable under the trade name Koresin®, a resin marketed by BASF, and which is obtainable by reacting acetylene and para tertiary butyl phenol. Koresin® comprises units of formula (II), where R1= HC-CH3, and optionally units of formula (I II) and / or (IV), where R1= H2C-CH2and where R2in formulae (II) , (I II) and (IV) is tert. -butyl.

[0043] The po ly (a I ky I ph en o I ic) resins, in particular those having repeating units of formula (I), typically have a number average molecular weight in the range of 500 to 5000 g / mol, in particular in the range of 800 to 3000 g / mol, especially in the range of 1000 to 2500 g / mol, as determined by size-exclusion chromatography (SEC) in Tetrahydrofuran (TH F) with refractive index detector (Rl) detector and polystyrene calibration.

[0044] The po ly (a I ky I ph en o I ic) resins, in particular those having repeating units of formula (I), typically have an OH value in the range of 50 to 500 mg KOH / g, preferably in the range of 100 to 350 KOH mg KOH / g, more preferably in the range of 150 to 250 mg KOH / g, as determined by esterification with acetic anhydride, hydrolysis of the excess reagent, titration with KOH, correction with acid number (all acids). The OH value can be determined e. g. by the method disclosed in DIN 53240-1:2013 or DIN 53240-2:2007.

[0045] Preferably, the poly(al ky I phenol ic) resins, in particular those having repeating units of formula (I), typically have a softening point in the range of 100 to 200 ° C, in particular in the range of 110 to 180 ° C, preferably in the range of 120 to 170 ° C, more preferably in the range of 130 to 160 ° C, especially in the range of 135 to 155

[0046] C, as determined by the ring-and-ball method according to DI N 52011:1986.

[0047] The po ly (a I ky I ph en o I ic) resins, in particular those having repeating units of formula (I), typically have a dropping point in the range of 110 to 180° C, preferably in the range of 120 to 170° C, more preferably in the range of 140 to 160° C as determined by Ubbelohde method according to DIN 51801:1980. Generally, the poly(al kylphenolic) resins are used in an amount in the range of 0.5 to 30% by weight, preferably 1 to 20% by weight, more preferably 2 to 15% by weight, even more preferably 4 to 12% by weight, based on the total weight of the TPU and the poly(alkylphenolic) resin.

[0048] The thermoplastic polyurethane (TPU) are well known in the art and commercially available. They are typically reaction products of at least the following monomer components

[0049] • isocyanate component (A) having a functionality of at least 2, hereinafter also referred to diisocyanates and polyisocyanates;

[0050] • isocyanate reactive component (B) and

[0051] • optionally chain extender component (C) having a functionality of 2 or higher.

[0052] Generally, the thermoplastic polyurethane, is obtainable by reacting an organic isocyanate component (A), typically being at least one diisocyanate or a combination of at least one diisocyanate and at least one polyisocyanate, having an isocyanate functionality of more than 2, e. g. 2.1 to 4, with an isocyanate-reactive component (B), preferably comprising a polymeric polyol having a in particular a functionality in the range of 1.8 to 3.0. The reaction is typically carried out in the presence of at least one catalyst which catalyzes the reaction of the isocyanate reactive groups of the compounds of component (B) with the isocyanate groups of the isocyanate component A.

[0053] In the context of TPU, the term “functionality” refers to the average number of isocyanate groups per molecule and isocyanate reactive functional groups per molecule, respectively, in the respective components (A), (B) and (C). Isocyanate reactive functional groups are those which react with isocyanate groups of the component (A) in an addition reaction by formation of a bond. Isocyanate reactive functional groups typically have 1 or 2 Zerewitinoff-active hydrogen atoms.

[0054] The components organic isocyanate component (A), isocyanate reactive component (B), and chain extender (C) are also addressed individually or together as building components. The building components, if applicable, including the catalyst, optional auxiliaries and / or additives are also called input materials.

[0055] Here and throughout the specification, the terms “isocyanate” and “isocyanate component (A)” are used synonymously.

[0056] The isocyanate component (A) is typically selected from organic isocyanate and preferably comprises at least one diisocyanate compound. In particular, the isocyanate component (A) is selected from the group consisting of aliphatic isocyanates, alicyclic isocyanates, araliphatic isocyanates, aromatic isocyanates and combinations thereof.

[0057] More preferred the isocyanate component (A) is selected from the group consisting of aromatic isocyanates, aliphatic isocyanates, alicyclic isocyanates and combinations thereof.

[0058] The isocyanate component (A) typically comprises one or more diisocyanate compounds, i. e. isocyanates having an isocyanate functionality of 2. In addition to the diisocyanate, the isocyanate component A may also contain one or more isocyanates having an isocyanate functionality of > 2, e. g. in the range of 2.1 to 4.

[0059] Suitable diisocyanates include aromatic diisocyanates, aliphatic diisocyanates, cycloaliphatic diisocyanates or combinations thereof. In some embodiments, the isocyanate component A includes one or more aromatic diisocyanates. In some embodiments, the isocyanate component A is essentially free of, or even completely free of, aliphatic diisocyanates. In other embodiments, the isocyanate component A includes one or more aliphatic diisocyanates and / or cycloaliphatic diisocyanates. In some embodiments, the isocyanate component A is essentially free of, or even completely free of, aromatic diisocyanates. In some embodiments, mixtures of aliphatic and aromatic diisocyanates may be useful.

[0060] Examples of useful diisocyanates include aromatic diisocyanates such as 4,4'-methylenebis(phenyl isocyanate (4,4’-MDI), 2,4-diphenylmethane diisocyanate (2,4-MDI), 2,2'-diphenylmethane diisocyanate (2,2’-MDI), m-xylene diisocyanate (XDI), phenylene-l,4-diisocyanate (1,4-PDI), naphthalene-l,5-diisocyanate (N DI), 4, 4'-diisocyanato-l,2-di phenyl ethane, 3,3'-di methyl -4, 4'- bi phenylene diisocyanate (TODI) and toluene diisocyanate (TDI); as well as aliphatic diisocyanates such as ethylene diisocyanate (EDI), 1,4-butane diisocyanate (BDI), 1,6-hexamethylene diisocyanate (HDI), decane-1, 10-diisocyanate, 1,12-dodecane diisocyanate (DDI), lysine diisocyanate (LDI); and cyclo aliphatic diisocyanates like isophorone diisocyanate (IPDI), 1,4-cyclohexyl diisocyanate (CHDI), and dicyclohexylmethane- 4,4'-diisocyanate (H12MDI). Isomers of these diisocyanates may also be useful. Mixtures of two or more polyisocyanates may be used. In some embodiments, the diisocyanate is MDI and / or H12MDI. In some embodiments, the polyisocyanate consists essentially of MDI. In some embodiments, the polyisocyanate consists essentially of H12MDI.

[0061] According to a further embodiment, the aromatic diisocyanate is selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, urethane-modified liquid 4,4'-diphenylmethane diisocyanate and / or 2,4-diphenylmethane diisocyanate, 4,4’-diisocyanato-l,2- diphenylethane, 1,5-naphthalene diisocyanate, and combinations thereof. In another preferred embodiment, the aromatic diisocyanate is 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate or 4,4'-diphenylmethane diisocyanate (MDI) , or a mixture thereof, especially preferred is 4,4’- diphenylmethane diisocyanate. In a more preferred embodiment, the aromatic diisocyanate is diphenylmethane diisocyanate (MDI). In an especially preferred embodiment, the aromatic diisocyanate is 4,4'-diphenylmethane diisocyanate (4,4'- MDI).

[0062] Aliphatic isocyanates are preferred when stability of the TPU against electromagnetic waves e.g. light is of importance, whereas aromatic isocyanates are preferred when high mechanical strength of the thermoplastic polyurethane is required. A further advantage of aliphatic isocyanate is that it may be produced biobased.

[0063] In a preferred group of embodiments, the aliphatic isocyanate is selected from the group consisting of 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-docecane diisocyanate, and combinations thereof. In a group of more preferred embodiments, the aliphatic isocyanate is 1,6-hexamethylene diisocyanate (HDI). In another more preferred group of embodiments, the aliphatic isocyanate is 1,5-pentamethylene diisocyanate. This has the additional advantage, that it can be produced bio based.

[0064] According to a further group of embodiments, the alicyclic isocyanate is preferably selected from the group consisting of isophorone diisocyanate, 1,4-cyclohexane diisocyanate, l-methyl-2,4-cyclohexane diisocyanate, l-methyl-2,6-cyclohexane diisocyanate, dicyclohylmethanediisocyanate and its corresponding isomer mixture, 4,4'-, 2,4-, and 2,2'-dicyclohexylmethane diisocyanate and their corresponding isomer mixtures, and combinations thereof. In this group of embodiments, the alicyclic isocyanate is more preferably 4,4'-dicyclohexylmethane diisocyanate (H12MDI).

[0065] According to the invention, the isocyanate component (A) comprises or is at least one of hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate and combinations thereof especially 4,4’-M DI , dicyclohexylmethane, diisocyanate, especially H12MDI, and combinations thereof. Here and throughout the specification, the terms “isocyanate-reactive component (B)" and “compound reactive with isocyanate” are used synonymously.

[0066] The isocyanate-reactive component (B) typically comprises and oligomer or polymer and preferably has a number average molecular weight of at least 0.4 x 103g / mol, e. g. from 0.4 x 103g / mol to 20 x 103g / mol, preferably in the range of 0.4 x 103g / mol to 10 xlO3g / mol, more preferably in the range of 0.7 x 103g / mol to 8.0 x 103g / mol, even more preferred in the range of 0.8 x 103g / mol to 8.0 x 103g / mol, or a mixture of an oligomer or polymer and a low molecular isocyanate functional compound having a lower molecular weight, e. g. in the range of 0.05 x 103g / mol to 0.4 x 103g / mol. Preferably, the isocyanate-reactive component (B)has an average functionality with regard to the isocyanate reactive groups of about 2, e. g. in the range of 1.8 to 2.3, preferably in the range of 1.9 to 2.2, especially 2. In particular the isocyanate reactive groups of the compounds of component (B) are hydroxyl groups.

[0067] If desired, a chain extender may be used in the production of the TPU. The chain extender preferably has a molecular weight lower than that of the compounds of the isocyanate reactive component (B), e. g. in the range of 0.05 x 103g / mol to 0.4 x 103g / mol.

[0068] Preferably, the isocyanate-reactive component (B) has on statistical average at least 1.8 and at most 3.0 Zerewitinoff-active hydrogen atoms. This number is also referred to as the functionality of the isocyanate-reactive compound and indicates the quantity of the isocyanate-reactive groups of the molecule calculated theoretically down to one molecule from a quantity of substance. Functional groups having Zerewitinoff-active hydrogen atoms include the hydroxyl group, the amino group, the mercapto group and the carboxylic acid group. The preferred isocyanatereactive group of compounds of the isocyanate-reactive component (B) is the hydroxyl group. The functionality of the compound is preferably in the range of 1.8 to 2.6, further preferred in the range of 1.9 to 2.2 and especially preferred 2.

[0069] In a preferred embodiment, the isocyanate-reactive component (B) comprises an oligomeric or polymeric polyol, hereinafter briefly polyol, having in particular a number average molecular weight in the range of 0.4 x 103g / mol to 20 x 103g / mol, preferably in the range of 0.4 x 103g / mol to 10 xlO3g / mol, more preferably in the range of 0.7 x 103g / mol to 8.0 x 103g / mol, even more preferred in the range of 0.8 x 103g / mol to 8.0 x 103g / mol. In this group of embodiments the polymeric polyol typically contributes at least 50% by weight, in particular at least 70% by weight or up to 100% by weight, to the total weight of the component (B). Preference is given to polyols of the group of polyesterols, polyetherols, polyetheresterols, and polycarbonate-ols, commonly also referred to collectively as “polyols” or as polyester polyols, polyether polyols, polyetherester polyols, and polycarbonate polyols. These polyols preferably have an average functionality in the range of 1.8 to 2.3, preferably in particular in the range of 1.9 to 2.2, more particularly of 2. In this case they may also be denominated as polyester diols, polyether diols, polyetherester diols, and polycarbonate diols.

[0070] In a preferred embodiment, the component (B) comprises a polyester polyol. Here and throughout the specification, the terms “polyester” and “polyester polyol” are used synonymously. Preferably, the polyester is selected from the group consisting of reaction product of polyhydric alcohol, polymerization product of lactone and polymerization product of di-carboxylic acids with polyhydric alcohols. The term “lactone” refers to cyclic esters of hydroxycarboxylic acids. Such polyester polyols include hydroxyl-terminated reaction products of polyhydric alcohols, polyester polyols obtained as the polymerization product of lactone, e.g. caprolactone, in conjunction with a polyol, and polyester polyols obtained by the polymerization of a di-carboxylic acid, e.g. adipic acid, with a polyhydric alcohol. Preferred polyester polyols include polymerization product of lactone or polycaprolactone and the ones obtained by the polymerization of a di-carboxylic acid with a polyhydric alcohol.

[0071] Preferably, the polyester polyol is obtained by polymerizing a di-carboxylic acid with a polyhydric alcohol. Preferred di-carboxylic acid is at least one of C4-C12dicarboxylic acid, while at least one of C2-C14diol are suitable as polyhydric alcohols. Preferably the C4-C12dicarboxylic acid is selected from the group consisting of an aliphatic dicarboxylic acid preferably selected from succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid and sebacic acid, or is a mixture thereof, and an aromatic dicarboxylic acid, preferably selected from phthalic acid, isophthalic acid and terephthalic acid, or a mixture thereof. More preferably, the dicarboxylic acid is selected from the group consisting of succinic acid, glutaric acid, adipic acid, suberic acid, phthalic acid, isophthalic acid and terephthalic acid, or is a mixture thereof. Most preferably, the dicarboxylic acid it is selected from the group consisting of adipic acid, suberic acid and phthalic acid, or is a mixture thereof.

[0072] Preferably, C2-C14diol used for obtaining the polyester polyol is selected from the group consisting of ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5- pentanediol, 1,6-hexanediol, 1,10-decanediol, 2,2-dimethyl-propane-l,3-diol, 1,3- propanediol, 2-methyl-l,3-propanediol and dipropylene glycol, or is a mixture thereof. More preferably, the diol is selected from the group consisting of ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10- decanediol or a mixture thereof. Most preferably, it is selected from the group consisting of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, or is a mixture thereof.

[0073] Suitable diols for producing polyesterols also include polyetherdiols as defined below, e. g. polyoxyethylenediol, polyoxypropylenediol, polyoxyethylene-co- oxypropylenediol and polytetrahydrofurane. In this case, the polyestersols are also referred to polyetheresterols.

[0074] Polyester polyols have less stability against hydrolysis and are preferred in applications where biodegradability is required.

[0075] In a preferred embodiment, the isocyanate-reactive component (B) comprises or is a polyesterol, preferably the polyesterol having a number-average molecular weight (Mn) of not more than 12000 g / mol, preferably not more than 6000 g / mol, more particularly not more than 4000 g / mol. In particular, the polyesterol is a polyesterol based on butanediol and adipic acid.

[0076] In another preferred embodiment, the component (B) comprises a polyether diol, in particular a polyether diol selected from the group of polyethyleneoxides (polyoxyethenediol), polypropyleneoxides (poly- 1,2 -propanediol), polyethyleneoxide-co-propyleneoxide and polytetrahydrofuranes (poly-1, 4-butane diol). In a preferred embodiment the polyetherpolyol, in particular the polytetrahydrofuran has a number average molecular weight in the range of 0.6 x 103g / mol to 1.7 x 103g / mol, more preferably with a number average molecular weight in the range of 0.8 x 103g / molto 1.4 x 103g / mol, even more preferably with a number average molecular weight in the range of 0.9 x 103g / mol to 1.1 x 103g / mol, and most preferably 1.0 x 103g / Mol. Preferred polyether polyols include polytetramethylene ether glycol (also referred as PTMEG), poly-1, 3-propanediol and poly 1,4-butanediol. Particularly preferred is PTHF, preferably having a number average molecular weight Mn in the range of 500 g / mol to 3.0 xlO3g / mol, preferably in the range of 0.6 x 103g / mol to 2,0 x 103g / mol, more preferably in the range of 0.7 x 103g / mol to 1.8 x 103g / mol. They are commercially available under the tradename PolyTHF®.

[0077] Polyetherpolyols have the advantage that it is more stable against hydrolysis and thus will be applied in applications where this is a requirement.

[0078] In a preferred group of embodiments, the isocyanate-reactive component (B) comprises or is a combination of a polyesterol and a polyetherol. In another preferred embodiment, the polyol comprises or is a polycarbonate diol, preferably an aliphatic polycarbonatediol. Preferred polycarbonate diols are polycarbonate diols based on alkane diols. The production of polycarbonate diols can be carried out by polycondensation of phosgene with diols or by ring-opening polymerization of cyclic carbonates. As a preferred alternative to phosgene synthesis, a transesterification with carbonic acid diesters is applied.

[0079] Preferred polycarbonate diols are strictly OH-difunctional polycarbonate diols, preferably strictly OH-difunctional aliphatic polycarbonate diols. Preferred polycarbonate diols are based on butanediol, pentanediol or hexanediol. In particular polycarbonate diols are based on 1,4-butanediol, 1,5-Pentanediol, 1,6- Hexanediol, 3-Methylpentane-(l,5)-diol, or are mixtures thereof. More preferred polycarbonate diols are based on 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, or mixtures thereof. More preferred are polycarbonate diols based on butanediol and hexanediol, polycarbonate diols based on pentanediol and hexanediol, polycarbonate diols based on hexanediol, or mixtures thereof.

[0080] Preferably, the polycarbonate diol has a number average molecular weight Mn in the range from 0.5 x 103to 4.0 x 103g / mol, preferably in the range from 0.65 x 103g / mol to 3.0 x 103g / mol, preferred in the range from 0.8 x 103g / mol to 2.5 x 103g / mol, more preferred the number average molecular weight is in the range of 1.8 x 103g / mol to 2.2 x 103g / mol or in the range of 0.8 x 103g / mol to 1.2 x 103g / mol.

[0081] Polycarbonate diols have better permeability for microwave, less dirt uptake and show better flame retardancy.

[0082] In another preferred embodiment, the polyol comprises or is a polysiloxane diol. Preferably the oligo- or polysiloxane has the formula (I):

[0083] HO-[Ak-O]q-Ak-Si(R2)-[O-Si(R2)]p-O-Si(R2)-Ak-[O-Ak]q.-OH formula (I) wherein Ak preferably represents C2-C4alkylene, R represents C1-C4alkyl, and each of p, q and q’ independently is a number selected from the range of 0 to 50. In more preferred moieties (B) of formula (I), p ranges from 1 to 50, especially from 2 to 50.

[0084] In one preferred embodiment Ak represents identical alkylene units in each residue (Cl), in yet another preferred embodiment Ak represents different alkylene units in the same residue (Cl). In one preferred embodiment Ak is ethylene or propylene within the same residue (Cl).

[0085] One preferred polydimethylsiloxane diol has formula (II) formula (II) with m in the range from 5 to 80, or has formula (III) formula (III).

[0086] The molecular weight is preferably in the range of 0.500 x 103g / Mol to 15 x 103g / Mol, more preferred in the range of 1.0 x 103g / Mol to 3.0 x 103g / Mol.

[0087] In one preferred embodiment, the polyol is a single polyol, in another preferred embodiment the polyol is a mixture of two or more polyols as preferred above. In one preferred embodiment it is a mixture of at least one polyether polyol and at least one polycarbonate diol.

[0088] In a case of using a mixture of polyether polyols and polycarbonate diols, polycarbonate diols preferably are used in amount of less than 50% by weight, preferably less than 35% by weight, more preferably less than 15% by weight, and most preferably less than 5% by weight, based on the total weight of the polyol mixture.

[0089] Preferably, the TPU is obtainable from an isocyanate component (A) and a polyol component (B) comprising at least one aliphatic polymeric polyol.

[0090] In particular, the polyol component (B) comprises at least one aliphatic polymeric polyol, which is in particular selected from the group consisting of aliphatic polyesterols, aliphatic polyetherols, aliphatic polycarbonate polyols and combinations thereof, especially from the group consisting of aliphatic polyesterdiols, aliphatic polyetherdiols, aliphatic polycarbonate diols and combinations thereof.

[0091] In a particularly preferred group of embodiments, the TPU is obtainable from an isocyanate component (A) comprising or being at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and combinations thereof and a component (B) comprising at least one aliphatic polymeric polyol, which is in particular selected from aliphatic polyesterols, polyetherols, polycarbonate polyols and combinations thereof, especially from aliphatic polyesterdiols, polyetherdiols, polycarbonate diols and combinations thereof. In this group of embodiments the aliphatic polymeric polyol typically contributes at least 50% by weight, in particular at least 70% by weight or up to 100% by weight, to the total weight of the component (B).

[0092] In a particularly preferred group of embodiments, the TPU is obtainable from an isocyanate component (A) comprising at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and combinations thereof and a component (B) comprising at least one aliphatic polymeric polyol, which is in particular selected from aliphatic polyesterols, polyetherols, polycarbonate polyols and combinations thereof, especially from aliphatic polyesterdiols, polyetherdiols, polycarbonate diols and combinations thereof. In this group of embodiments the aliphatic polymeric polyol typically contributes at least 50% by weight, in particular at least 70% by weight or up to 100% by weight, to the total weight of the component (B).

[0093] Preferably, the chain extender component is selected from aliphatic di- and polyols having a number average molecular weight in the range of 50 to 400 g / mol. Examples include aliphatic diols, cycloaliphatic diols and araliphatic diols, such as ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol, cyclohexane dimethanol (CHDM), hydroquinone bis(2-hydroxyethyl)ether (HQEE) and mixtures thereof. Especially, the chain extender is butanediol, hexanediol, cyclohexane dimethanol (CHDM), hydroquinone bis(2-hydroxyethyl)ether (HQEE), or is a mixture thereof.

[0094] In order to adjust the hardness and melt flow index of the TPU, the molar ratios of the quantities of the building components and chain extender, if used the water, can be varied, whereby the hardness and melt viscosity increase with increasing content of isocyanate or with increasing content of isocyanate and chain extender, while the melt flow index decreases.

[0095] The thermoplastic polyurethane generally has a Shore A hardness in the range of 50 to 150 shore A, preferably in the range of 65 to 120 Shore A, more preferably in the range of 70 to 100 Shore A, even more preferably in the range of 74 to 98 Shore A.

[0096] The thermoplastic polyurethane generally has a melt flow index (2.16 kg, 150°C) in the range of 1 to 70 g / lOmin, preferably in the range of 1.5 to 65 g / lOmin, more preferably in the range of 2 to 60 g / lOmin, even more preferably in the range of 5 to 55 g / lOmin, as determined by JIS K 7210 at 150° C with a load of 2.16 kg. The thermoplastic polyurethane, preferably has a weight-average molecular weight of at least 0.04xl06g / mol, more preferably at least 0.06 x 106g / mol, more preferably at least 0.07 xlO6g / mol, and more preferably at least 0.08 xlO6g / mol. The upper limit for the weight-average molecular weight of TPU is generally determined by the processability and the desired range of properties. Preferably, the weight-average molecular weight does not exceed 0.5 xlO6g / mol, more preferably 0.4 xlO6g / mol, more preferably 0.25 xlO6g / mol, and more preferably 0.2 xlO6g / mol. The weight-average molecular weight as outlined herein preferably are determined by gel permeation chromatography, preferably according to DIN 55672- 1, whereas dimethylformamide (DMF) is used as solvent.

[0097] Generally, the TPU has a flow beginning temperature (Tfb) in the range of 50 to 160° C, preferably in the range of 50 to 155° C, more preferably in the range of 50 to 150° C, more preferably in the range of 50 to 140° C, most preferably in the range of 50 to 120° C as determined by capillary rheometer, e.g. by type Shimadzu flowtester.

[0098] Generally, the TPU has a melting temperature in the range of 50 to 160° C, preferably in the range of 50 to 160° C, more preferably in the range of 50 to 150° C, as determined by as determined by differential scanning calorimetry according to ASTM E 794-06(2018) with a heating rate of 20 K / min.

[0099] Particularly, the TPU is suitable for hot melt.

[0100] Preferred TPUs for hotmelt applications are commercially obtainable under the brand name ELASTOLLAN HOTBOND, such as following grades:

[0101] ELASTOLLAN HOTBOND AH-530, ELASTOLLAN HOTBOND AH-535, ELASTOLLAN HOTBOND AH-560, ELASTOLLAN HOTBOND AH-560XF. ELASTOLLAN HOTBOND AH-560F ELASTOLLAN HOTBOND AH-560T, ELASTOLLAN HOTBOND AH-562, ELASTOLLAN HOTBOND AH-567, ELASTOLLAN HOTBOND AH-571, ELASTOLLAN HOTBOND AH-571E, ELASTOLLAN HOTBOND AH-573, ELASTOLLAN HOTBOND AH-576, ELASTOLLAN HOTBOND AH-579, ELASTOLLAN HOTBOND AH-580, ELASTOLLAN HOTBOND AH-582, ELASTOLLAN HOTBOND AH-583, ELASTOLLAN HOTBOND AH-588, ELASTOLLAN HOTBOND AH-591, ELASTOLLAN HOTBOND AH-620, ELASTOLLAN HOTBOND AH-650, ELASTOLLAN HOTBOND AH-652, ELASTOLLAN HOTBOND AH-660, ELASTOLLAN HOTBOND AH-661, ELASTOLLAN HOTBOND AH-670, ELASTOLLAN HOTBOND AH-780, ELASTOLLAN HOTBOND AH-781, ELASTOLLAN HOTBOND AH-782, ELASTOLLAN HOTBOND AH-810, ELASTOLLAN HOTBOND SP 100, the DESMOMELT grades, e. g. the DESMOMELT U grades such as DESMOMELT U 230 and DESMOMELT U 320 and the PEARLBOND TPU grades, such as PEARLBOND 100 TPU, PEARLBOND 103 TPU, PEARLBOND 106 TPU, PEARLBOND 1160 TPU, PEARLBOND 120 TPU, PEARLBOND 121 TPU, PEARLBOND 122 TPU, PEARLBOND 123 TPU, PEARLBOND 180 TPU, PEARLBOND 220 TPU, PEARLBOND 223 TPU, PEARLBOND 300 TPU, PEARLBOND 301 TPU, PEARLBOND 305 TPU, PEARLBOND 5708 F3 TPU, PEARLBOND 5713 TPU, PEARLBOND 5717 NT2 TPU, PEARLBOND 920 TPU, PEARLBOND 960 TPU, PEARLBOND DI PPI 19 TPU, PEARLBOND 410a TPU and PEARLBOND 410b TPU.

[0102] More preferred TPU is commercially obtainable under the trade names ELASTOLLAN HOTBOND AH-560XF, ELASTOLLAN HOTBOND SP 100 and ELASTOLLAN HOTBOND AH-652.

[0103] The essentially difunctional component B, typically an oligomeric or polymeric diol, and the chain extender (C), if present also the water, are preferably be used in mole ratios of 1:1 to 1:5, preferably 1:1.5 to 1:4.5, such that the resulting mixtures of the building components (B) and chain extender (C) have a hydroxyl equivalent weight of greater than 200, and in particular from 230 to 450, while for the production of harder thermoplastic polyurethane, e.g. having a Shore A hardness greater than 98, preferably in the range of 55 to 75 Shore D, the molar ratios of compound (B) and chain extender (C) are generally in the range of 1:5.5 to 1:15, preferably 1:6 to 1:12, such that the resulting mixtures of compound (B) and chain extender (C) have a hydroxyl equivalent weight of 110 to 200, preferably 120 to 180.

[0104] In a preferred embodiment, the TPU is obtained by the reaction of the components (A) and (B) and optionally (C) in the presence of a catalyst. The catalyst is either a single catalyst or is a mixture of several catalysts.

[0105] The catalysts preferably accelerate the reaction between the NCO groups of the isocyanates and the isocyanate reactive groups of the component (B) and of the chain extender. In a preferred embodiment the catalyst is selected from the group consisting of a tertiary amine and an organic metal compound or is a mixture thereof.

[0106] A preferred organic metal compound is selected from the group consisting of titanic ester, iron compound, tin compound, and bismuth salt, or is a mixture thereof. A preferred iron compound is iron (III) acetylacetonate. A preferred tin compound is selected from the group consisting of tin diacetate, tin dioctoate, tin dilaurate, tin (II) neodecanoate, and dialkyl tin salts of aliphatic carboxylic acids, or a mixture thereof. Preferably the catalyst is tin dioctoate, tin (II) neodecanoate, or is a mixture thereof. A preferred titanic ester is tetrabutyl orthotitanate. In preferred bismuth salts, the bismuth is present in the oxidation states 2 or 3, in particular 3, with preference being given to salts of carboxylic acids, preferably carboxylic acids having from 6 to 14 carbon atoms, particularly preferably from 8 to 12 carbon atoms. A very preferred bismuth salt is bismuth (III) neodecanoate, bismuth 2- ethylhexanoate, or bismuth octanoate, or is a mixture thereof.

[0107] The catalyst is preferably used in an amount of from 0.0001 to 0.1 part by weight per 100 parts by weight of the polyol. Preference is given to using tin catalyst, in particular tin dioctoate.

[0108] In a preferred embodiment, the composition comprises SDO (tin (II) 2- ethylhexanoate), tin (II) neodecanoate, or a mixture thereof, preferably used in quantities of 0.35-0.4 parts per weight, referring to the whole composition.

[0109] In preferred embodiment, an auxiliary or additive is comprised in the composition. In a preferred embodiment the auxiliary or additive is selected from the group consisting of surface-active substance, a filler, a flame retardant, a nucleating agent, an oxidation stabilizer, a lubricating aid, a demolding aid, a dye, a pigment, an inorganic filler an or an organic filler, a reinforcing agent, a plasticizer, an antistatic agent, a stabilizer, preferably a stabilizer against hydrolysis, light, heat or discoloration, inorganic fillers, organic fillers, reinforcing agents, plasticizers, or is a mixture thereof.

[0110] Stabilizer in the sense of this invention is an additive which protects a plastic or a plastic composition against harmful environmental influences. A preferred example is a primary or secondary antioxidant, a sterically hindered phenol, a hindered amine light stabilizer, an UV absorber, a phosphite, a hydrolysis inhibitor, a quencher, and a flame retardant. Examples of commercial stabilizers are given in Plastics Additives Handbook, 5th Edition, H. Zweifel, ed., Hanser Publishers, Munich, 2001 ([1]), p.98-S136.

[0111] Preferably, the UV absorber has a number average molecular weight greater than 0.3 x 103g / mol, in particular greater than 0.39 x 103g / mol. Furthermore, the preferred UV absorber has a molecular weight not exceeding 5 x 103g / mol, particularly preferred not exceeding 2 x 103g / mol.

[0112] The UV absorber is preferably selected from the group consisting of cinnamates, oxanil ides, benzophenones and benzotriazole, or is a mixture thereof, particularly suitable as UV absorbers is benzotriazole. Examples of particularly suitable UV- absorbers are Tinuvin® 213, Tinuvin® 234, Tinuvin® 312, Tinuvin® 571, Tinuvin® 384 and Eversorb® 82.

[0113] Preferably, the UV absorbers is added in quantities of 0.01 wt.% to 5 wt.% based on the total weight of the composition, preferably 0.1 wt.% to 2.0 wt.%, in particular 0.2 wt.% to 0.5 wt.%.

[0114] Often a UV stabilization based on an antioxidant and a UV absorber as described above is not sufficient to guarantee a good stability of the composition against the harmful influence of UV rays. In this case, in addition to the antioxidant and / or the UV absorber, or as single stabilizer, a hindered-amine light stabilizer (HALS) is added to the composition.

[0115] Examples of commercially available HALS stabilizers can be found in Plastics Additive Handbook, 5th edition, H. Zweifel, Hanser Publishers, Munich, 2001, pp. 123-136.

[0116] Particularly preferred hindered amine light stabilizers are bis- (1 ,2,2,6,6- penta—i methyl pi peridyl) sebacat (Tinuvin® 765, Ciba Spezialitatenchemie AG) and the condensation product of 1 - hyd roxyethy I -2 ,2,6,6-tetra methy I -4- hydroxypiperidine and succinic acid (Tinuvin® 622). In particular, the condensation product of l-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidines and succinic acid (Tinuvin® 622) is preferred, if the titanium content of the finished product is less than 150 ppm by weight, preferably less than 50 ppm by weight, in particular less than 10 ppm by weight, based on the components used.

[0117] HALS compounds are preferably used in a concentration of from 0.01 wt.% to 5 wt.%, particularly preferably from 0.1 wt.% to 1 wt.%, in particular from 0.15 wt.% to 0.3 wt.%, based on the total weight of the composition.

[0118] A particularly preferred UV stabilizer contains a mixture of a phenolic stabilizer, a benzotriazole and a HALS compound in the preferred amounts described above.

[0119] Further information on the above-mentioned auxiliaries and additives can be found in the technical literature, e.g. Plastics Additives Handbook, 5th edition, H. Zweifel, ed., Hanser Publishers, Munich, 2001.

[0120] The composition comprising the thermoplastic polyurethane can be produced discontinuously or continuously. A preferred process is the reaction extruder process, the belt line process, the “one shot” process, preferably the "one-shot process or the reaction extruder process, most preferably the reaction extruder process.

[0121] These processes are used either by directly mixing the building components or alternatively by applying the prepolymer process.

[0122] Polyisocyanate prepolymers are obtainable by reacting above-described polyisocyanate in excess, at temperatures of 30 to 100 ° C, with the compound reactive isocyanate, preferably the polyol.

[0123] In the "one-shot" process, the building components diisocyanate and the compound reactive with isocyanate, preferably polyol, more preferably polyol diol, and in a further preferred embodiment also the chain extender, and, in further preferred embodiments, also a catalyst, are mixed with each other. This is done either in succession or simultaneously, in a preferred embodiment in the presence of a catalyst. In the extruder process, the building components diisocyanate and compound reactive with isocyanate, preferably the polyol, more preferably the diol, in a preferred embodiment also the chain extender, and, in further preferred embodiments, also the catalyst are mixed. The mixing in the reaction extruding process is done preferably at temperatures in the range of 100° C to 280° C, preferably in the range of 140° C to 250° C.

[0124] In order to prepare the thermoplastic polyurethane, the building components isocyanate the polyol and the chain extender, are reacted in preferred embodiments in the presence of a catalyst, and optionally auxiliaries and / or additives in such quantities that the equivalent ratio of NCO groups of the isocyanate, preferably the diisocyanate to the sum of the hydroxyl groups of the component reactive with isocyanate and chain extender is 0.95:1 to 1.10:1, preferably 0.98:1 to 1.08:1 and in particular 1.0:1 to 1.05:1. In a very preferred embodiment the equivalent ratio is 1.0:1.

[0125] The thermoplastic polyurethane obtained, preferably is in the form of a granulate or a powder. Auxiliaries and additives may be added during the synthesis of the thermoplastic polyurethane or are added to the thermoplastic polyurethane. The latter is preferred. This is especially the case, if the additive or auxiliary is not inert against the isocyanate, the chain extender, the compound reactive with isocyanate, or the catalyst.

[0126] In a preferred embodiment, the synthesis of the thermoplastic polyurethane is done in an extruder, more preferably a twin-screw extruder is used. The twin-screw extruder operates with positive conveying and thus allows a more precise setting of the temperature and output quantity on the extruder.

[0127] The compositions of the present invention are usually produced by incorporating the po ly (a I ky I ph en o I ic) resin into the TPU, in particular to the molten TPU. Incorporation can be achieved by any method suitable for mixing thermoplastic polymers. Typically, the mixing of the thermoplastic polyurethane with the po ly (a I ky I ph en o I ic) resin and optionally other components of the composition is carried out in a mixing unit, such as a kneader or preferably an extruder, in particular a twin-screw extruder. I n a preferred embodiment the po ly (a I ky I p he no I ic) resin is introduced into the mixing unit in a molten state. In particular, the po ly (a I ky I ph en o I ic) resin is introduced into the extruder downstream of the filling point in the flow direction of the TPU the extruder.

[0128] In a preferred embodiment, the compositions according to the invention are produced by processing the thermoplastic polyurethane, the po ly (a I ky I ph en o I ic) resin and optionally further ingredients of the composition. In another preferred embodiment, the compositions are produced by process comprising the provision of a TPU, preferably as a granulate, into which the poly (al kyl phenol ic) resin and optionally other components of the composition are then introduced in at least one further step, or else a plurality of steps. I n another preferred embodiment, a master batch of the TPU and the po ly (a I ky I ph en ol ic) resin, e. g. by mixing the thermoplastic polyurethane with the po ly (a I ky I ph en o I ic) resin in a suitable mixing device, preferably in a kneader or an extruder, optionally with further ingredients, such as flame retardants, UV stabilizers or other auxiliaries. The masterbatch is then incorporated into further TPU, optionally together with other components of the composition.

[0129] The invention is further described by examples. The examples relate to practical and in some cases preferred embodiments of the invention that do not limit the scope of the invention.

[0130] 1. Preparation of the inventive composition

[0131] The commercially available TPU hotmelt (Elastollan® Hotbond) once without any poly (al kyl phenol ic) resin (comparative examples 1, 2, 3 und 4) and once with the corresponding amount of Koresin, which is a commercially available po ly (a I ky I ph en o I ic) resin according to the invention (inventive examples 1-1, 1-2, 2- 1, 2-2, 3-1 and 3-2) were added to a conical twin screw mini-extruder (X-plore) under the conditions listed in the table 1. After 5 min recirculation in the extruder, the blends were collected and let cold down to room temperature. Additionally, one commercially available TPU hotmelt was prepared with a commercial hydrocarbon resin Piccotac® 1095 N, using the same method that was used for the preparation of the other examples (comparative example 4-1 and 4-2).

[0132] Table 1: Blending conditions a: the wt% refers to the total weight of the TPU and the poly (a I kyl p hen olio) resin b: Koresin® is poly(alkylphenolic) resin according to the invention c: Piccotac® 1095N is hydrocarbon resin based on C5 olefine (not according to the invention) Physical and chemical properties of the hotmelts 1 to 3, Koresin® and Piccotac® 1095N are summarized as follows:

[0133] 1.1 Hotmelt 1 (Elastollan Hotbond AH560 F)

[0134] Hardness: 75 ± 20 Shore A, as determined by DIN ISO 7619 Density at room temperature: 1.2 g / cm3, as determined by DIN EN ISO 1138-1 A

[0135] Tensile Strength: = 120 kg / cm2, as determined by ASTM D 412 Elongation at break: = 600%, as determined by ASTM D 412 Melt flow index (2.16 kg, 150°C): 20 ± 50 g / lOmin, as determined by DIN EN ISO 1133

[0136] Flow beginning temperature: 95 ± 10° C, as determined by capillary rheometer (type Shimadzu flowtester)

[0137] I

[0138] 1.2 Hotmelt 2 (Elastollan Hotbond SP 100)

[0139] Hardness: 75 Shore A, as determined by DIN ISO 7619

[0140] Density at room temperature: 1.2 g / cm3, as determined by DIN EN ISO 1138-1 A

[0141] Tensile strength: 70 kg / cm2, as determined by ASTM D 412 Elongation at break: 800%, as determined by ASTM D 412 Melt flow index (2.16 kg, 150° C): 50 g / 10 min, as determined by DIN EN ISO 1133- Flow beginning temperature: 95° C, as determined by capillary rheometer (type Shimadzu flowtester)

[0142] 1.3 Hotmelt 3 (Elastollan Hotbond AH 652)

[0143] Hardness: 97 ± 2 Shore A, as determined by DIN ISO 7619 Density at room temperature: 1.2 g / cm3, as determined by DIN EN ISO 1138-1 A -

[0144] Melt flow index (2.16 kg, 150° C): 10 ± 3 g / 10 min, as determined by DIN EN ISO 1133

[0145] Flow beginning temperature: 60 ± 10° C, as determined by capillary rheometer (type Shimadzu flowtester)

[0146] 1.4 Po ly (a I ky I p he no I ic) resin according to the invention (Koresin® of BASF SE)

[0147] Ring and ball softening point: 135 -150° C, as determined by DIN 52011 Ubbelohde dropping point: 140 -160° C, as determined by DIN51801 Density (20° C): 1.02 -1.04 g / cm3, as determined by DIN EN ISO 787-10 Solubility: soluble in hydrocarbons, e. g. 10 g will completely dissolve in 90 g toluene;

[0148] 1.5 Piccotac® 1095N (conventional aliphatic polymeric tackifier of Synthomer) Ring and ball softening point: 96° C, as determined by ASTM E 28 DACP cloud point: 47° C from 1:1 mixture of xylene and diacetone alcohol

[0149] Molecular weight, Mn: 1100 g / mol, as determined by GPC using polystyrene standards, elution with THF (Mw: 1980 g / mol, Mz: 3510 g / mol)

[0150] 2. Measurement of melt viscosity

[0151] The viscosity of the inventive examples 1 to 3 and comparative example were measured as follows:

[0152] 2.1 Device:

[0153] Following devices and tools were used to measure viscosity of IE1 to 3 and CE1:

[0154] - Brookfield viscometer DV2T-HB with thermal oven

[0155] - PC with Rheocalc T software

[0156] - Disposable spindle SCA4-27

[0157] - Disposable sample tube for thermosel furnace

[0158] - Needle-nose pliers

[0159] - Precision scale

[0160] 2.2 Detailed description of the measurement:

[0161] 11 to 13 g of the sample were weighed into the disposable sample tube and then placed in the thermosel oven. In doing so, it was made sure that the tube clicks into place in the recess at the bottom. To do this, the tube with the needle-nose pliers was turned until it slips into the recess. After that, the RHM sample is heated to 75° C in the thermosel oven with manual operation and melted in the process.

[0162] The SCA4-27 spindle is then inserted into the spindle adapter for disposable spindles and fixed in place. As soon as the specimen has melted, the spindle is guided into the melt by lowering the viscometer until the alignment guide of the viscometer touches the groove of the thermal furnace. In doing so, it was necessary to ensure that the viscometer and the furnace are level.

[0163] To homogenize the sample and improve temperature distribution, the spindle is rotated by manually switching on the viscometer. The speed of rotation is adjusted so that the relative torque is in the range of 50% - 90%.

[0164] The method "Standard methods - RHM viscosity profile" is selected for the measurement. The parameters of the method are as follows

[0165] • Spindle SCA4-27

[0166] • Temperature step program with multipoint measurement 75° C at 4 U / Min.

[0167] 90° C at 10 U / Min.

[0168] 110° C at 10 U / Min.

[0169] 130° C at 22 U / Min. and 10 U / Min.

[0170] 150° C at 22 U / Min. and 10 U / Min.

[0171] 3. Differential scanning calorimetry (DSC)

[0172] The Differential scanning calorimetry measurement was conducted with the inventive examples 1 to 3 and comparative example as follows:

[0173] Approx. 10 mg of the TPUs or the blends were weighed in an aluminum pan and sealed. A heating, cooling and second heating run at 20 K / min were performed using a differential scanning calorimeter from TA-lnstruments, model Q 2000.

[0174] 4. Results

[0175] The results of viscosity and DSC measurements of the inventive examples as well as comparative examples are presented in the following tables.

[0176] 4.1 Viscosity

[0177] 4.1.1 Example with Hotmelt 1 (AH 560 XF) and Koresin

[0178] 4.1.2 Example with Hotmelt 2 (SP100) and Koresin 4.1.3 Example with Hotmelt 3 (AH 652) and Koresin .1.4 Example with Hotmelt 1 (AH 560 XF) and Piccotac 1095N .2 DSC .2.1 Example with Hotmelt 1 (AH 560 XF) and Koresin .2.3 Example with Hotmelt 3 (AH 652) and Koresin 4.2.4 Example with Hotmelt 1 (AH 560 XF) and Piccotac 1095N

[0179] The viscosity as well as the melting temperature results showed that the inventive examples have a lower viscosity with similar melting temperatures as the TPU

[0180] Hotmelts without poly(al ky I phenol ic) resin, which represents a processing advantage compare to the state of the art resin.

Claims

Claims1. Use of poly(alkylphenolic) resins for lowering the melt viscosity of thermoplastic polyurethanes (TPU).

2. The use of claim 1, wherein the po ly (a I ky I ph en ol ic) resin has a softening point in the range of 100 to 200° C, in particular in the range of 110 to 180° C, preferably in the range of 120 to 170° C, as determined by the ring-and-ball method according to DIN 52011:1986 and / or wherein the po ly (a I ky I ph e no I ic) resin has a dropping point in the range of 110 to 180° C, preferably in the range of 120 to 170° C, more preferably in the range of 140 to 160° C as determined by the Ubbelohde method according to DIN 51801:1980.

3. The use according to any one of preceding claims, wherein the poly(al kyl phenol ic) resin has a number average molecular weight in the range of 500 to 5000 g / mol, in particular in the range of 800 to 3000 g / mol, especially in the range of 1000 to 2500 g / mol, as determined by size-exclusion chromatography (SEC) in Tetrahydrofuran (THF) with refractive index detector (Rl) detector and polystyrene calibration.

4. The use according to any one of preceding claims, wherein the poly(al kyl phenol ic) resin has OH value in the range of 50 to 500 mg KOH / g, preferably in the range of 100 to 350 mg KOH / g, more preferably in the range of 150 to 250 mg KOH / g, as determined by esterification with acetic anhydride, hydrolysis of the excess reagent, titration with KOH, correction with acid number (all acids).

5. The use according to any one of preceding claims, wherein the poly(al kyl phenol ic) resin comprises repeating units of formula (I)wherein i. R1is a linear or branched alkylene group with 2 to 10 carbon atoms;ii. R2is, a linear or branched, saturated or unsaturated aliphatic hydrocarbon group with up to 10 carbon atoms.

6. The use or the composition according to claim 5, wherein R2in formula (I) is a aliphatic hydrocarbon group with 2 to 8 carbon atoms, and where R2is in particular tertiary butyl.

7. The use according to claim 5 or 6, wherein the poly (al kyl phenol ic) resin is a formaldehyde-free po ly (a I ky I ph en o I ic) resin.

8. The use according to any one of claims 5 to 7, wherein the poly (al kyl phenolic) resin is obtainable by the reaction of para tertiary butyl phenol with acetylene.

9. A composition containingA) a thermoplastic polyurethane (TPU) andB) at least one poly(a I kyl phenol ic) resin, except for poly(al kyl phenol ic) formaldehyde resins.

10. The composition according to claim 9, where the po ly (a I ky I ph en o I ic) resin is as defined in anyone of claims 5 to 8.

11. The use of any one of claims 1 to 8 or the composition according to one of claims 9 or 10, wherein the amount of poly (al kyl phenol ic) resin is in the range of 0.5 to 30% by weight, preferably 1 to 20% by weight, more preferably 2 to 15% by weight, even more preferably 4 to 12% by weight, based on the total weight of the TPU and the po ly (a I ky I ph en ol ic) resin.

12. The use or the composition according to any one of preceding claims, wherein the TPU is suitable for hot melt.

13. The use or the composition according to any one of preceding claims, wherein the TPU has a flow beginning temperature (Tfb) in the range of 50° C to 160° C, as determined by capillary rheometer and / or wherein the TPU has a melting temperature in the range of 50 to 160° C, as determined by differential scanning calorimetry according to ASTM with a heating rate of 20 K / m i n .

14. The use or the composition according to any one of preceding claims, wherein the TPU is obtainable from an isocyanate component (A) and a polyol component (B) comprising at least one aliphatic polymeric polyol.

15. The use or the composition according to claim 14, wherein the aliphatic polymeric polyol is selected from the group consisting of aliphatic polyesterol, aliphatic polyetherols, aliphatic polycarbonate polyols and combinations thereof and where the isocyanate component (A) comprises at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and combinations thereof.

16. A process for the preparation of the composition according to claims 9 to 15, wherein the poly(alkylphenolic) resin is incorporated into the TPU, in particular to a molten TPU, wherein the TPU and the poly(alkylphenolic) resin are in particular mixed in an extruder.

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