DE102006036539A1 - Thermoplastic processable molding material with improved transparency, useful to prepare e.g. molded articles, comprises a mixture of in situ compatible polyamide-thermoplastic polyurethane-blend comprising e.g. lactam and catalyst - Google Patents

Abstract

Thermoplastic processable molding material (I) with improved transparency comprises a mixture of in situ compatible polyamide-thermoplastic polyurethane (TPU)-blend comprising (in wt.%): (a) 4-12C-lactams or its mixture (50-95), (b) TPU (5-50), (c) at least a basic catalyst (0.05-5), (d) activator and/or co-catalyst (0-3), and (e) usual additives, dyes and/or blending partner (0-40); where the polyamide-TPU-blend is obtained by mixing the components in a fusion mixing apparatus at 180-260[deg] C and carrying out anionic lactam polymerization with adjusted short retention time. An independent claim is included for the preparation of (I) comprising providing the lactam and TPU either separately or combinely, through the inlet of a fusion mixing apparatus; carrying out anionic lactam polymerization; and separating the melted mixture and processed; where the mixing process is carried out at 180-260[deg] C, preferably 210-240[deg] C.

Description

The The present invention relates to thermoplastically processable molding compositions with improved transparency, consisting of a mixture of in situ compatibilized polyamide TPU (thermoplastic Polyurethane) blends that provide excellent contact transparency have a method for producing the blends and their Use. By means of continuous anionic polymerization of lactams in the presence of thermoplastic polyurethane a melt mixing device, in particular an extruder, are Compatible polyamide TPU blends accessible. These blends according to the invention are particularly suitable for the production of transparent or contact-transparent films, hollow profiles and injection molded parts.

The primary Motivation for mixing (blending) of immiscible or incompatible Polymers is the creation of new materials with a tailor made Combination of physical properties that the properties are superior to the respective individual components. In the prior art it is known that the desired Properties of such multiphase materials very strong depend on the morphology of the systems and the interfacial adhesion between the phases. immiscible Polymer blends are thermodynamically unstable, and therefore show a poor dispersion and poor interfacial adhesion, which in turn is not satisfactory mechanical properties result. Therefore there is a desire to improve compatibility through Use of (reactive) compatibilizers, about the interface adhesion too improve and control the morphology of the polymer blends.

A effective strategy for compatibilizing incompatible Polymers are therefore in situ formed block or graft copolymers at the interface, which act as emulsifiers to stabilize the morphology formed and about the interfacial adhesion between to strengthen the phases. In situ polymerization is another effective way to change the morphology control the polymer blends and to the dispersion of the phases improve. In terms of of the latter method has been in the past rubber or thermoplastic modified polymers, e.g. Epoxy / thermoplastic System much attention.

Polyamide 6 has several disadvantages in terms of its mechanical properties. Therefore, it has long been tried to overcome these disadvantages by melt blending with other plastics or by in situ polymerization. With regard to the latter method, many efforts have been made, including using prepolymers or smaller molecules having functional groups that react with ε-caprolactam, followed by polymerization to achieve a copolymer and compatibilization of the incompatible blend components with the copolymer. For example, amine- or hydroxy-terminated prepolymers (eg EP 0167908 ) to be incorporated into ε-caprolactam by in situ polymerization so that copolymers can be formed.

thermoplastic Polyurethane elastomers (TPU) represent a very important class of Materials and they were also very widely used for various applications used. The properties of the TPU can be changed by varying the ratios be tailored to the hard and soft segments.

Also in the mixture of polyamides with polyurethanes plays the selection the diisocyanate and Diol components in terms of type and segment length a crucial role for the achievable properties. Thus, e.g. by combination of a suitable polyether-based TPUs clearly demonstrate the toughness of polyamides be improved. Likewise, the polyether groups contribute to Hydrogen bonds to train to the amide groups. In addition, in the prior art reported blends of polyamide 6 and TPU with diblockcopolyurethane amides have been compatibilized. These blends were made by melt blending in a Brabender mixer made so that multi-phase systems achieved could become.

DE 3545033 A1 (EMS-INVENTA AG) describes thermoplastically processable mixtures of 10 to 90% hydrolytically produced polyamide, 10 to 90% TPU (thermoplastic polyurethane) and 5 to 50% grafted polyolefin. The macroscopically homogeneous blends are obtained by extrusion, preferably in a twin-screw extruder. The blends have elastomeric properties, improved resistance to flexing and hydrolysis. Grafted polyolefin is needed as a compatibilizer because polyamide and TPU do not form stable polymer blends due to their incompatibility. The blends described have little or no transparency due to the composition chosen.

DE 698 03 779 T2 (DuPont) describes a process for producing polyamide-polyurethane microblends wherein up to 20% of a thermoplastic segmented polyurethane can be incorporated. In the preparation, the two polymers are mixed at high temperature (240 to 260 ° C) in the extruder. A construction of macromolecules or a polymerization does not take place in this extrusion process. Preferably, PA 66 is used as the polyamide component. Task of DE 698 03 779 T2 is the recycling of tights that contain predominantly spandex fibers.

US 6,713,596 B1 describes a process for anionic lactam polymerization, wherein other polymers such as polyolefins, polyamides, polyphenylene ethers can be added. The actual polymerization and thus the blend production takes place in a casting mold and not in an extruder (cf claim 7).

US 3,320,335 (Monsanto) describes a process for anionic lactam polymerization in the presence of 0.05 to 30 mol% of N-substituted urethanes and polyurethanes which act as activators. In this method, the achievable molecular weight of the polylactam formed is inversely proportional to the urethane concentration used, so that prohibit too high TPU concentrations, high molecular weights should be achieved in the final product. With regard to the activated anionic lactam polymerization, the process requires an extremely long polymerization time of 1 to 2.5 hours. This is due, inter alia, to the fact that the polymerization in the process described is carried out below the melting temperature of the polylactam.

CS 191691 describes a process for the anionic polymerization of lactam in the presence of polyurethane as activator, wherein the polyurethane is previously completely dissolved in the lactam. Sufficient conversion is achieved only with a high polymerization time of 30 to 60 minutes and complete solubility of the TPU in the molten lactam. According to the function of the polyurethane as an activator, only low concentrations are used. Preference is given to working at temperatures below the melting point of the polylactam.

In Polymer International 55, 643-649, (2006) describes a method for producing TPU-PA6 blends by in situ Polymerization of caprolactam described. These are blends with 2.5 to 10 wt .-% polyether-based polyurethane elastomer in a Brabender mixer made. This is a homogeneous solution TPU and caprolactam at 160 ° C prepared and by adding sodium caprolactamate the anionic Polymerization triggered. Immediately after addition of the basic catalyst, the mixture becomes in one at 180 ° C transferred preheated vessel and polymerized in the oven at the same temperature for 60 minutes. The Authors characterize the blends thus produced as compatible and single phase.

requirement But here too, the TPU is completely in the lactam melt triggers and no segregation during the polymerization takes place.

The The present invention therefore has the object, thermoplastic Processable molding compositions of a mixture of polyamide and TPU (thermoplastic polyurethane), which is a very good Have transparency or contact transparency and also a low Have residual lactam content. Here are the structure of the polyamide component from the monomers, the generation of the compatibilizer and the Blend these components with TPU in a simple, continuous Extrusion process performed become. Thus, another object of this invention is a method to provide short polymerization times and independently from the solution behavior the TPU component in lactam is feasible.

The Molding compounds of polyamide-TPU blends are intended for the production of transparent Films and hollow sections can be used.

• A1) 50 bis 95 Gew.-% eines C₄-C₁₂ Lactams oder C₄-C₁₂ Lactam Gemisches,
• A2) 5 bis 50 Gew.-% TPU(thermoplastisches Polyurethan),
• A3) 0,05 bis 5 Gew.-% wenigstens eines basischen Katalysators,
• A4) 0 bis 3 Gew.-% Aktivatoren und/oder Co-Katalysatoren,
• A5) 0 bis 40 Gew.-% weitere übliche Additive, Farbstoffe und/oder Blendpartner,

wobei die Summe der Komponenten A1 und A2 100 Gew.-% ergibt, und A3 sowie A4 sich jeweils auf A1 und A5 sich auf die Summe A1 bis A4 beziehen. Die Mischung der Polymerkomponenten und die anionische Lactampolymerisation laufen zeitlich nacheinander oder zumindest teilweise gleichzeitig ab und die so hergestellten Blends weisen eine Transmission, gemessen nach ASTM 1003, von mindestens 80% bei einer Schichtdicke von 800 μm (gemessen an Folien) auf (vgl. Anspruch 1).This object is achieved according to the invention by the thermoplastically processable molding compositions having improved transparency, consisting of a mixture of in situ compatibilized polyamide TPU (thermoplastic polyurethane) blends according to claim 1. The blends according to the invention contain:

• A1) from 50 to 95% by weight of a C ₄ -C ₁₂ lactam or C ₄ -C ₁₂ lactam mixture,
• A2) 5 to 50 wt.% TPU (thermoplastic polyurethane),
• A3) from 0.05 to 5% by weight of at least one basic catalyst,
• A4) 0 to 3 wt .-% activators and / or co-catalysts,
• A5) 0 to 40% by weight of further customary additives, dyes and / or blend partners,

wherein the sum of the components A1 and A2 gives 100% by weight, and A3 and A4 relate respectively to A1 and A5 to the sum A1 to A4. The mixture of the polymer components and the anionic lactam polymerization proceed chronologically successively or at least partially simultaneously and the blends produced have a transmission, measured according to ASTM 1003, of at least 80% at a layer thickness of 800 μm (measured on films) (cf. 1).

The However, the invention also relates to a process for the preparation of the above mentioned molding compositions with improved transparency, wherein the anionic Lactam polymerization either before mixing with TPU (A2) expires or wherein the components lactam (A1) and TPU (A2) are either separated or together in the catchment area of a melt mixing device, in particular an extruder, anionic lactam polymerization triggered and the mixture is melted and the mixture produced discharged becomes. The temperature of the melt during the mixing process is in the range of 180 and 260 ° C, preferably in the range of 200 to 240 ° C, in particular between 220 ° and 240 ° C, set (see claims 19 and 20).

The molding composition according to the invention is used for the production of fabrics and moldings, in particular of transparent films, protective layers, top coverings of sports equipment and for the production of hollow profiles, in particular of pipes used (see claims 23 and 24).

In the dependent claims are advantageous embodiments of the invention.

Prefers According to the invention blends used, containing 10 to 40 wt .-% TPU. In particular, be Mixtures containing 10 to 30 wt .-% TPU used.

As lactam (C ₄ to C ₁₂ ) are preferably used caprolactam and laurolactam. If lactam mixtures are used, at least 20 mol%, preferably at least 50 mol%, in particular at least 70 mol%, of laurolactam are used in the mixture with other lactams. Lactam can also be replaced by a lactone, in particular caprolactone, up to 50 mol%. In a preferred variant, only lactam-12 is used.

The candidate TPUs are based on polyether, polycarbonate or polyester segments. In the case of the polyester-based TPU, preference is given to those whose soft segments are polycaprolactone blocks. In the case of the polyether segments, preference is given to those based on the monomers ethylene oxide and / or propylene oxide and / or tetrahydrofuran. The polyester segments are preferably based on adipic acid and glycols, such as ethylene glycol or butanediol. The preferred polycarbonate segments are prepared by polycondensation of diethyl or dimethyl carbonate with diols, such as hexanediol. The hard segments can be both aromatic and aliphatic in nature. Preferably, the TPU used are based on the diisocyanates MDI (diphenylmethane diisocyanate), TDI (toluene diisocyanate), PPDI (para-phenylene diisocyanate), NDI (naphthalene diisocyanate), HDI (hexamethylene diisocyanate), IPDI (isophorone diisocyanate), H ₁₂ MDI (dicyclohexylmethane diisocyanate), TMXDI (m In particular, the hard segments of the TPU are based on the diisocyanates MDI and TDI, TPUs based on polycaprolactone soft segments and TDI and / or MDI hard segments are preferably used The TPUs used according to the invention , have an OH end group concentration of <50 mmol / kg, preferably <20 mmol / kg, in particular less than 5 mmol / kg A higher OH end group concentration disturbs the anionic lactam polymerization and thus leads to a higher lactam concentration in the polymer mixture can be used with higher OH concentration, they must be previously z u or concealed simultaneously with the melting of the components in the extruder, such as with carbonylbiscaprolactam. The Shore hardness of the TPU used in the invention is in the range of A70 to D75, preferably in the range A80 to D65, in particular between A85 and D55.

As a basic catalyst for the formation of the required for the anionic lactam lactamate anion, the known initiator systems are used, such as alkali metals and metal hydrides, alkali metal and Erdalkalilactamate or Grignard agents. In a preferred embodiment of the invention, the liquid catalyst system consisting of sodium acetanilide and tetrabutylurea, as described in the EP 01 514 887 A1 is used. In a further embodiment, the catalyst used is a liquid system of sodium phenylmethyl carbamate and N-methyl-pyrrolidone, as in EP 01 240 237 B1 described, used. The in the two aforementioned patent documents as well as in EP 0 786 486 B1 Liquid initiators described are hereby expressly included. As activators, free or so-called capped isocyanates, such as caprolactam-capped MDI, or carbodiimides, such as Dicyclohexylcarbodiimid, or Carbonylbiscaprolactam be used separately or as in some of the above-mentioned liquid initiators combined with the catalyst.

Of the Term transparent molding compounds, consisting of polyamide-TPU blends, as used in the invention blends, or the molding compounds formed therefrom, whose light transmission is at least 80%, preferably at least 85% and in particular at least 87% is when the molding material the blend is in the form of a film of 800 microns thickness. The value of Light transmission is always defined as part of this text according to the method ASTM D1003 (illuminant CIE-C). The measurement The light transmission was in the experiments below on a device with the name Haze Guard Plus of BYK Gardner (DE) at 800 (100) μm thick foils performed. The transmission value is for the visible wavelength range defined according to CE-C i. with significant intensities approx. between 400 and 770 nm. The films are for this purpose e.g. on a Collin flat film system produced, the cylinder temperature between 190 and 240 ° C and the roll temperature is between 10 and 50 ° C. Based on the 100 μm thick Slides are also determined by the Haze. The haze is for the molding compositions according to the invention at the most 10%, preferably at most 6%, in particular at most 3%.

Depending on the blend composition and the process conditions the mechanical properties of the PA-TPU blends according to the invention set in a wide range. Compared to conventionally produced PA-TPU blends enabled the inventive method the generation of flexible and highly flexible molding compounds. So wise the molding compositions according to the invention an E-modulus of preferably less than 1000 MPa, in particular smaller 600 MPa. Especially soft formulations have smaller moduli of elasticity 300 MPa. A polymer mixture generated in the twin-screw extruder (ZSK-25), consisting of 75 wt .-% hydrolytically produced polyamide-12 (Comparative Example VB2) and 25% by weight of Pearlthane 11T98 (Merquinsa, Spain) has one Modulus of elasticity of 1160 MPa. In contrast, by means of the method according to the invention prepared blend of the same composition (Example B8) one significantly lower modulus of elasticity of only 300 MPa. Also after The two-step process produced PA-TPU blends are clear more flexible than the analogous polymer mixtures based on the hydrolytic Polyamides. Thus, the molding composition of Comparative Example VB4 has a E modulus of 1260 MPa and that of Example B18 a clear lower modulus of 760 MPa. This clear difference in The mechanical properties clearly show that the molding compositions of the invention not by simple melt mixing of the components hydrolytically produced polyamide and TPU can be produced.

Of the Difference in structure and morphology of PA-TPU blends Base of anionic and hydrolytically produced polyamide disclosed also clear on the thermal behavior of the blends. While at all polymer blends (VB1-VB4) Based on hydrolytically produced polyamide the original Melting point of the polyamide in PA-TPU blend measured by DSC The polymer blends possess anionic-derived Polyamide always lower melting points than the underlying, high molecular weight polyamides. In the case of the PA12-TPU blends according to the invention for example, the melting temperatures determined by DSC 5 (Example B17) to 38 ° C (Example B9) below the melting temperature of the underlying Polyamide 12th

One Another advantage of the molding compositions of the invention and the resulting finished molded parts is the good transparency, especially at small layer thicknesses. The transparency of the molding compounds, characterized as Function of the transmission measured on foils with a thickness of 100 μm at least 92%, preferably at least 93% and especially at least 94%. Haze (haze) is for the molding compositions according to the invention at the most 10%, preferably at most 6%, in particular at most 3% if the cloudiness is determined on films with a thickness of 100 microns. Enable it these molding compounds the production of visually appealing, transparent Moldings or fabrics. Thicker moldings or films have good contact transparency on. So the transmission is measured on films with a thickness of 800 μm at least 80%, preferably at least 85% and especially at least 87%. One by injection molding from that described in Example B6 Molded round plate of dimension 2 × 70 mm still has excellent transparency, the transmission 84% and Haze is only 2.0%.

Also in terms of transparency, the blends are based on hydrolytic Polyamide has a different behavior, probably from some intolerance the PA and TPU components arises. The transparency (transmission) increases in the blend compositions according to the invention with increasing TPU concentration too, while based on the blends of hydrolytic polyamide show a reverse behavior.

The polyamide TPU blends have a residual lactam content of less than 7%, preferably less than 3% and more preferably less than 1%. Also PA-TPU blends based on mixtures of lauric and caprolactam generally have a Lactamrestgehalt of less than 5%. Due to the low Lactamrestgehaltes can be dispensed with a subsequent production process extraction. The molding compounds cause no or only small solid deposits in the thermoplastic forming.

The molding compositions of the invention have an MVR (melt volume rate) measured at 220 ° C and a 5 kg load of <500, <200, <100 cm ^3/10 min. and a solution viscosity (m-cresol, 0.5 wt .-%) of η _rel > 1.4, preferably> 1.5, in particular> 1.6. The melt and solution viscosity can be varied within a wide range depending on the composition and the production process. Thus, it is also possible to produce higher-viscosity molding compositions whose solution viscosity η _{rel is} significantly above 2. Thus, molding compounds are available whose solution viscosity η _rel , in the range of 1.4 to 3.0. A solution viscosity η _rel in the range between 1.6 and 2.5 and in particular between 1.7 and 2.2 is preferred.

The Preparation of the polyamide-TPU blends according to the invention carried out by continuous extrusion on a twin-screw extruder, wherein the polyamide component in situ by anionic polymerization is built. Because in this process several steps at the same time and / or carried out in succession In particular, long extruders with a high L / D ratio are used. The procedural embodiments differ essentially by the arrangement of dosages for the Raw materials (lactam, catalyst, activator, TPU), the type of activation the anionic polymerization and the addition of other additives and blend components. Furthermore, the preparation of the polyamide TPU blends according to the invention in one or two stages. In the two-stage process is first the polyamide component anionically polymerized and subsequently in a second step mixed with the TPU component. In the single-step process finds the lactam polymerization and the mixture of the components at least partially simultaneously.

Downstream of the actual lactam polymerization, it is optionally possible to use further blend components as blend components selected from the group of the polyamides and / or the polyesters and / or the polycarbonates and / or the modified polyolefins, in particular the acid-functionalized polyolefins, in addition to TPU up to 40, in the same or in a downstream extrusion pass % By weight. Polyamides, such as partially crystalline polyamides, such as, for example, PA 6, PA 46, PA 66, PA 610, PA 69, PA MXD6, PA11, PA12, PA612, PA6 / 12, PA 6T / 6I, PA 6T / 66, PA are preferred here 6T12, or amorphous polyamides such as PA MACM9-18, PA PACM9-18, PA 6I / 6T, PA MACMI / 12, PA PACMI / 12, PA 6I / 6T / MACMI / MACMT / 12, PA 3-6T, PA TMDT, PA 6I / MACMI / MACMT, PA 6I / PACMI / PACMT, PA 6I, PA 6 / IPDT, PA 6I / PACMT. Another class of blend components include polymers that act as proton donors. These can be used alone or in combination with low molecular weight to oligomeric proton donors for the purpose of stabilizing the anionic polymer melt. In this connection, let us refer to those in the patent documents EP 01249465 B1 and WO 04/035658 A1 listed stabilizers for anionic polymers, which are hereby expressly included.

The Activation of the anionic polymerization takes place either thermally or by added activators, e.g. Isocyanates, carbodiimides or carbonyl biscaprolactam. Be the TPU together with the lactam metered into the extruder, the TPU contained in the or regressed from the urethane groups by the reaction conditions Isocyanate groups as activators. In contrast to the low molecular weight Activators can in the present process according to the invention in the activation through the TPU component no direct relationship between the TPU concentration and the average molecular weight of the polymers formed be determined.

The by the anionic polymerization of lactams in the presence of TPU or by melt mixing of anionically produced polyamide with TPU and others formed polyamide TPU copolymers act as compatibilizers for polyamide and TPU.

For the preparation of the blends according to the invention by means of the single-stage process, lactam and TPU are either metered together into the feed zone of a twin-screw extruder (zone 1) via two separate metering devices or the lactam in zone 1 and the TPU are fed into a downstream zone (zones 3 to 10). In this case, the lactam or lactam mixture can be supplied to the extruder in the solid state, for example in the form of flakes, or in the molten state. In a preferred embodiment of the invention, the molten lactam is preheated to temperatures in the range of 160 to 200 ° C before entering the extruder in the liquid metering. Thus, the lactam already has a sufficiently high temperature when it enters the extruder, so that the polymerization starts immediately after the addition of the catalyst. This procedure accelerates the polymerization process and reduces the Lactamrestgehalt in the finished polymer alloy for a given residence time in the extruder or allows a reduction in the process length. The anionic lactam polymerization initiating catalyst is fed continuously in zone 1 or preferably in zone 2 of the extruder. The housings of the extruder are set for the process according to the invention to temperatures between 180 and 260 ° C. Preferably, a temperature range of 190 to 250 ° C, in particular selected between 210 and 240 ° C. Higher temperatures should be avoided in order to prevent degradation of the TPU to a large extent. Optionally, a further activator for the anionic lactam polymerization is additionally added in zone 1 or zone 2. A better embodiment concerning the activator feed consists in that, to initiate the anionic lactam polymerization, a so-called liquid initiator, which simultaneously contains activator and catalyst dissolved in a suitable solvent, is used.

Characteristic for this Variant of the method according to the invention is that in a single process step both the lactam polymerization, the copolymer formation as well as the mixture of all present in the system Components, including an optional catalyst neutralization takes place, and this for short residence times in the process section. The mean residence time for the entire process amounts to only 2 to 10 minutes, preferably 2 to 7 minutes, in particular 3 to 5 minutes.

When the polymer melt is discharged from the extruder, as in EP 01249465 B1 and WO 04/035658 A1 described, neutralized, resulting in processing and application stable polyamide TPU blends in a single extrusion pass.

In a preferred embodiment of the invention will the TPU feed (feeder) split, leaving a portion of the TPU via a separate dosing weigher together with the lactam in zone 1 and the other part in one concerning the conveying direction downstream zone, e.g. Zone 7 or 9 is metered. Through this Splits the TPU feed vary the morphology of the generated blend within wide limits. In this case, preferably 20 to 80%, in particular 20 to 50% of the total TPU dosed together with the lactam in zone 1. With this procedure can preferably be high TPU concentrations, in particular greater than 25 wt .-%, realize in the mixtures without the simultaneously occurring Disrupt lactate polymerization. As a result, this results in polyamide TPU blends with high TPU content and low lactam residual concentration. This is a requirement that can be dispensed with a subsequent extraction and during processing of the blends no sweating of the lactam takes place.

In With respect to the lactam used, a turnover of at least 93%, preferably of at least 97% and more preferably of at least 99% aspired.

At the Two-stage procedure is first the polyamide anionic with the aid of the above-mentioned catalysts and / or activators. The temperature is for this Polymerization in the range between 180 and 350 ° C and preferably in the range between 200 and 330 ° C. The polymer melt can then be granulated and later or later be mixed directly in a second extruder with the TPU. In order to the blends of the invention may be produced with their typical morphology the Polylactamschmelze not with the above stabilizers (Proton donors) are neutralized before the complete mixture the polyamide and TPU components have been completed. Otherwise prevail similar conditions as in hydrolytic polyamide, where compatibilizing structures during the pure mixing process are formed only to an insufficient extent (see claim 20). The two-stage process is fulfilled also the high demands regarding one possible low Lactamrestgehaltes. Due to the undisturbed implementation of anionic lactam polymerization results in this process variant compared to the single-step process tends to be lower Lactamrestgehalt.

A further preferred embodiment The present invention is characterized in that it the additives are one or more of the additives, selected from the group: chain regulators, catalysts, lubricants, anti-blocking agents, Stabilizers, in particular heat stabilizers, UV stabilizers, Proton donors for the neutralization of the catalysts, pigments, Dyes and / or impact modifier is. It is also possible Such a blend nanofillers to mix. As nanofillers Such substances are suitable which are finely distributed in the nanometer range and thus maintain sufficient transparency. The used according to the invention nanoscale fillers are preferably selected from the group of oxides, oxide hydrates of boron, aluminum, calcium, Gallium, indium, silicon, germanium, tin, titanium, zirconium, zinc, Yttrium or iron.

A preferred application of the molding compositions according to the invention of the polyamide-TPU blends relates to an upper covering, which serves as a protective layer and / or as a print carrier, for example for sports equipment such as skis, Snowboards, poles, rackets etc. or for housings can be used by appliances such as household appliances, electrical appliances, furniture, machinery. The top layer consists of a monolayer film based on polyamide TPU blends or of a multilayer film with at least one layer based on polyamide TPU blends. In particular, when using the soft polyamide TPU blends, a special feel, for example in the range of holding surfaces or switches of the utility objects, produce.

To the superficial Protection of objects such as decorative items, ski passes, display covers but also from the tops of skis and snowboards are as toppings protective films used. These protective films, which are laminated on the surface to be protected are usually made of a plastic material which meet special requirements got to. It must have sufficient mechanical values, e.g. regarding Scratch resistance, impact resistance and modulus of elasticity. About that in addition, during obtained a sufficient dimensional stability of the entire processing process stay and the material allowed during the storage of the calendered and cut films in stacks do not block. The material should also be suitable for back printing and be transparent, and it should be neutral in color. The plastic material can consist of a single layer, but it can also have a multi-layer structure. Furthermore, should have good heat resistance in the processing, the suitability for sublimation printing, a good Thermoformability or thermoformability and good UV resistance be given.

Preferred measures is it is according to the invention in the Structure of the topcoat around a monolayer film. Is possible but also a multilayer film, in which case at least one of Layers of this multilayer film, for example a two-layer film, forms the mixture or alloy of PA and TPU shown above, and further layers, for example based on TPU, ABS / TPU, PA 6, PA 66, PA 610, PA 6/12, PA 612, PA 11, PA 12, PA 11/12, PA 6I / 6T, PA MACM9-18, PA PACM9-18 or mixtures thereof could be. It may be the material of the additional layers to thermoplastic Materials such as preferably thermoplastic polyurethane (TPU) and mixtures thereof (blends) with ABS or polyamide 11 or polyamide 12 and its mixtures or copolymers act.

Farther The present invention relates to a process for the preparation a topping, as described above. Here is the Layer by extrusion of the polyamide TPU blends, and optionally existing Additives, produced at a temperature above 180 ° C. In the case of a multilayer film, this layer may be used together with one or more further film layers are coextruded. Following the step of (co) extrusion preferably follows Calendering the foil. The calendering can be heated between Rolling done.

It can also have one more (or more), in particular preferably pigmented layer can be provided. For example Is it possible, to use as pigment titanium dioxide and so a white background layer to effect. For example, such a layer based on of functional grafted polyolefins to be to guarantee the liability. This further layer can be between the layer based on polyamide-TPU blends and printing (eg, digital printing, ink-jet, sublimation printing, Pad printing, etc.), or is preferred the pressure between the layer based on polyamide-TPU blends and this pigmented layer is disposed. Such Slide can then to be protected Substrate in a lamination process adapted by the skilled person to the conditions applied using pressure and / or elevated temperature become. Also a gluing of the top covering with the substrate is conceivable, or a back injection such. in an IMD (in-mold Decoration) or an IML (in-mold labeling) method.

It also concerns the present invention, a use of a top cover, such as as described above, as superficial protection and / or printing support for sports equipment, in particular Skis, snowboards, surfboards, skateboards, poles, rackets etc. or for cases of devices like household appliances, Electrical appliances, Furniture, Tableware, textiles, shoes, signs, floors, in the automotive sector, machinery, or as superficial Protective layer for Display covers, as superficial Protective layer for print carrier such as ski passes, Decorative items etc.

Furthermore, the polyamide TPU blends can be used for the production of hollow profiles, in particular of tubes. The hollow profiles are preferably single-layered, but may also be of multilayer construction, the transparent layer of polyamide-TPU blend preferably forming the outer layer. These hollow profiles have the task of conducting or storing gases and / or liquids. Fields of application are eg pneumatic or hydraulic lines, brake or coolant lines, hollow sections with fill level indicator function as well as lines in the food sector, such as beverage lines. The pipes and pipes may be smooth, corrugated or wavy in some areas.

Furthermore The polyamide-TPU blends are also suitable for the production of hollow bodies, in particular Bottles and canisters, which are single or multi-layered.

One Another field of application is the blends according to the invention in 2-component injection molding, the polyamide-TPU blends being decorative and / or functional Serve purposes. In particular, the soft polyamide TPU blends are suitable here for the generation of hard-soft composites, wherein the soft component is clearly transparent or transparent colored can.

The Blends of the invention be in another embodiment used as a transparent cable sheath. For multi-layer jackets become the polyamide TPU blends preferably as outer layer used.

The Invention is illustrated by the following examples, without restricting it.

Examples

The Inventive blend production and in situ lactam polymerization was carried out on a twin-screw extruder ZSK 25 (d = 25 mm, L / D = 49, 12 housings) from W & P-Coperion. In Examples B1 to B10 and in Examples B15 and B16, lactam and TPU were over two separate dosing scales in the feeder (zone 1) and the catalyst FE5312 dosed in zone 2. In examples B11 to B14, the TPU feed was used split and share in zone 1 and the other part in zone 9 registered. Before further processing, the granules were added 80 ° C dried.

Subsequently were these blends on an Arburg Allrounder 320-210-750 (Hydronica) Injection molding machine to the required specimens processed, with the cylinder temperatures between 220 to 280 ° C and the Mold temperature between 20 and 60 ° C lay. The screw speed was 150 to 400 rpm.

In In Examples B17 to B19, the PA-TPU blends were in a two-step process produced. For this purpose, in the first step, lactam-12 and the catalyst FE5312 without added TPU at housing temperatures in the range from 180 to 330 ° C reacted with the ZSK-25 to an anionic polyamide-12 (FE7353). After drying the granules FE7353 was in a second step with the TPU component under the conditions given in Table 4 mixed in the extruder.

In Comparative Examples VB1 to VB4 was hydrolytically produced Polyamide-12 with various TPU's below those listed in Table 4 Conditions and mixing ratios extruded.

• • Zylindertemperaturen: 190 bis 240°C
• • Schneckendrehzahl: 40 bis 75 Upm
• • Walzentemperatur: 16 bis 50°C
• • Abzugsgeschwindigkeit: ca. 2,2 m/min
• • Lippenöffnung der Breitschlitzdüse: 0,7 mm
• • Foliendicke: 25 bis 1100 μm

The films were produced on a Collin flat film system (D = 30 mm, L / D = 25) equipped with a core-progressive 3-zone screw and a 300 mm slot die. For flat film production the following conditions were chosen:

• • Cylinder temperatures: 190 to 240 ° C
• • Screw speed: 40 to 75 rpm
• • Rolling temperature: 16 to 50 ° C
• • Take-off speed: approx. 2.2 m / min
• • Lip opening of the slot die: 0.7 mm
• • Film thickness: 25 to 1100 μm

The Compositions and the properties of the individual examples and Comparative Examples used for coming polyamide molding compounds as well as molded parts made of them are summarized in Table 1-4.

MVR:

(Melt volume rate) bei 220°C und einer Belastung von 5 kg nach ISO 1133

SZ:

Schlagzähigkeit nach ISO 179/1eU (Charpy)

KSZ:

Kerbschlagzähigkeit nach ISO 179/1eA (Charpy)

The molding compositions and moldings were tested as follows:

MVR:

(Melt volume rate) at 220 ° C and a load of 5 kg to ISO 1133

SZ:

Impact strength according to ISO 179 / 1eU (Charpy)

CSC:

Notched impact strength according to ISO 179 / 1eA (Charpy)

Tensile modulus, ultimate tensile strength and elongation at break were determined according to ISO 527 on ISO tensile specimens, standard ISO / CD 3167, type A1, 170 × 20/10 × 4 mm at a temperature of 23 ° C. The mechanical values were determined in a dry state.

The Yield stress and elongation, as well as tensile stress and strain of the Films were tested by means of the tensile test according to ISO 527 (test speed 100 mm / min). The films had a thickness of 100 microns and were 15 mm wide.

Of the Puncture test was made according to ISO 6603-2 at 100 microns thick foils performed.

The relative viscosity (η _rel ) was determined at 20 ° C. on a 0.5% strength m-cresol solution according to DIN EN ISO-Nom 307.

The Melting temperature was determined by differential scanning calorimetry (DSC) at a heating rate of 20 ° C / min according to ISO standard 11357-1 / -2 certainly. The temperature is given for the peak maximum.

transmission and cloudiness (Haze) were at 23 ° C with a Haze-Gard Plus from Byk-Gardner according to ASTM D-1003 (CIE Lichtart C) on films of thickness 100, 800 and 1100 μm as well as round plates of dimension 70 × 2 mm determined. Transmission and Haze are irradiated in% of the Amount of light indicated.

lactam:

Of the Content of residual lactam is gas chromatographed after extraction with methanol determined by the method of the internal standard (Oenantholactam). For this purpose, 2000 mg of sample and 19.8 mg of oenantholactam in a 100 Weigh out a round bottomed flask and dissolve with 60 ml of methanol for 8 h backflow cooked. After filtration through a 0.2 μm disposable filter, the samples supplied to the gas chromatograph (Injection volume: 1 μl).

In the examples, the following components used:

1. Thermoplastic polyurethane TPU Type Manufacturer Modulus of elasticity (MPa) Shore hardness soft segment Pearlthane D11T65 Merquinsa, Spain 410 D64 polycaprolactone Pearlthane 11T98 Merquinsa, Spain 125 D52 (A98) polycaprolactone Pearlthane D11T86 Merquinsa, Spain 75 A86 polycaprolactone

2. Catalyst for triggering the anionic lactam polymerization:

• - FE5312: Sodium acetanilide (19.0% by weight) dissolved in tetrabutylurea

3. Lactam and polyamide components

• - caprolactam and laurolactam; Water content less than 0.01% by weight
• - Grilamid L20 is a medium-viscosity polyamide-12 with η _rel = 1.95.
• - FE7353 is a polymer produced by anionic polymerization of lactam 12 polyamide 12, a solution viscosity of η _rel = 2.05, a MVR of 110 cm ^3/10 min. and a lactam residue content of 0.36 wt%. Based on lactam-12, the catalyst FE5312 was used in a concentration of 2.5% by weight.

Claims (24)

Thermoplastically processable molding compositions with improved transparency, consisting of a mixture of in situ compatibilized polyamide TPU (thermoplastic polyurethane) blends comprising: A1) 50 to 95 wt .-% of a C ₄ -C ₁₂ lactam or C ₄ -C ₁₂ lactam Mixtures, A2) from 5 to 50% by weight of TPU (thermoplastic polyurethane), A3) from 0.05 to 5% by weight of at least one basic catalyst, A4) from 0 to 3% by weight of activators and / or cocatalysts , A5) from 0 to 40% by weight of further customary additives, dyes and / or blend partners, the sum of the components A1 and A2 giving 100% by weight and A3 and A4 in each case being based on A1 and A5 A4, and the blends are obtained either by introducing a mixture of a polyamide prepared from the components A1, A3 and A4 and the components A2 and A5 or by introducing the mixture of the components A1 to A5 in a melt mixing device, melting the resulting mixture therein and discharging the mixture thus produced, wherein the temperature of the melt during the mixing process in the is kept between 180 and 260 ° C and short residence times are set, wherein the polyamide component is prepared by an activated continuous anionic lactam polymerization and the mixture of the polymer components and the anionic Lactampolymerisation time sequentially or at least partially run simultaneously. Molding compositions according to claim 1, characterized in that it has a transmission, measured according to ASTM 1003, of at least 80%, measured on films with one layer thickness of 800 μm, preferably at least 85% and in particular at least 87%, exhibit. Molding compositions according to claim 1 or 2, characterized in that the haze (Haze) of the molding compositions measured to ASTM D-1003 at most 10%, preferably at most 6%, in particular not more than 3% is, when the measurement is performed on films of thickness of 100 microns. Molding compounds according to one of the preceding claims 1 to 3, characterized in that they have a residual lactam content less than 7% by weight, preferably less than 3% by weight and more preferably less than 1% by weight. Molding compositions according to one of the preceding claims 1 to 4, characterized by an MVR (melt volume rate), measured at a temperature of 220 ° C and a load of 5 kg of less than 500, in particular less than 200, in particular less than 100 cm ³ / 10 min. Molding compositions according to one of the preceding claims 1 to 4, characterized in that the polyamide TPU blends have a solution viscosity η _rel of greater than 1.4, preferably greater than 1.5, in particular greater than 1.6. Molding compounds according to one of the preceding claims 1 to 6, characterized in that the polyamide TPU blends as Component A2 10 to 40 wt.% TPU, in particular 10 to 30 wt. TPU included. Molding compounds according to one of the preceding claims 1 to 7, characterized in that as component A1 in the polyamide-TPU blends Caprolactam or laurolactam can be used. Molding compounds according to one of the preceding claims 1 to 7, characterized in that as component A1 lactam mixtures be used, wherein at least 20 mol%, preferably at least 50 mol%, in particular at least 70 mol% of laurolactam in the mixture present with other lactams. Molding compositions according to claim 1, 8 and 9, characterized in that used in component A1 Lactam up to 50 mol% by a lactone, in particular by caprolactone, is replaced. Molding compounds according to one of the preceding claims 1 to 10, characterized in that as component A1 in the Polyamide TPU blends exclusively Lactam 12 is used. Molding compounds according to one of the preceding claims 1 to 11, characterized in that as component A2 in the Polyamide TPU blends TPU be used on polyether, polycarbonate or Polyester segments based. Molding compositions according to claim 1 or 12, characterized in that the TPU used an OH end group concentration of less than 50 mmol / kg, preferably less than 20 mmol / kg, in particular preferably less than 5 mmol / kg. Molding compositions according to claim 1, 12 or 13, characterized in that the Shore hardness of TPU in the range of A70 to D75, preferably in the range A80 to D65, especially in the range between A85 and D55. Molding compositions according to one of the preceding claims 1 to 14, characterized in that the additives (A5) are one or more additives selected from the group the chain regulator, the catalysts, the lubricant, the anti-blocking agent, the stabilizers, in particular the heat stabilizers, the UV stabilizers, the proton donors to neutralize the catalysts, the pigments, the dyes and / or the impact modifier, the nanofillers or the other foreign polymers as blend partners selected from the group of the polyamides and / or the polyesters and / or the polycarbonates and / or the modified polyolefins, in particular the acid-functionalized polyolefins. Molding compounds according to any one of the claims 1 to 14, characterized in that as catalyst (A3) for execution the anionic polymerization, a liquid catalyst system consisting from sodium acetanilide and tetrabutylurea is used. Molding compounds according to any one of the claims 1 to 14, characterized in that as catalyst (A3) a Liquid catalyst system from Natriumphenylmethylcarbamat and N-methyl-pyrrolidone used becomes. Molding compounds according to any one of the preceding claims 1 to 17, characterized in that residence times of 2 to 10 Minutes, preferably from 2 to 7 minutes, more preferably from 3 to 5 minutes for lactam polymerization, copolymer formation and the mixture all components present in the system, including one optional catalyst neutralization, are set. Process for the preparation of a thermoplastic processable molding composition with high transparency according to a the claims 1 to 18, characterized in that the components lactam (A1) and TPU (A2) either separately or together in the catchment area a melt mixing device can be registered, the anionic Lactam polymerization triggered and melting the mixture and discharging the generated mixture is, wherein the temperature of the melt during the mixing process in Range between 180 and 260 ° C, preferably in the range from 190 to 250 ° C, in particular between 210 and 240 ° C is set. Process for the preparation of a thermoplastic Processable molding compound with high transparency, according to a the claims 1 to 18, characterized in that the component lactam (A1), the component A3 and the component A4 together in the catchment area a melt device for the production of polyamide registered When the lactam polymerization is initiated, the mixture is melted and the generated mixture is discharged as a polymer melt, wherein the temperature of the melt during of the mixing process in the range between 180 and 350 ° C, preferably in the range between 200 and 330 ° C is set, the polymer melt then granulated and in time later or directly with TPU (A2) in a second melt mixing device mixed, melted the mixture and discharged the mixture produced wherein the temperature in the second melt mixing device while of the mixing process in the range between 180 and 260 ° C and preferred in the range between 180 and 240 ° C is set. Method according to claim 19 and 20, characterized in that at least a part of TPU-feeding is split and in a downstream zone of the melt mixing device is added to the mixture. Method according to one the claims 19 to 21, characterized in that the melting device a screw extruder, in particular a twin-screw extruder is. Use of a thermoplastic molding composition according to one the claims 1 to 18, for the production of fabrics and moldings, in particular of transparent films, protective layers, top coverings of sports equipment and for the production of hollow profiles, in particular of pipes. Moldings, obtained from a thermoplastic molding composition according to a the claims 1 to 18.