DE102010007820A1 - Extrudate made from thermoplastic-polyurethane composition useful as a self-extinguisher, comprises a polyurethane, an exfoliated nanoclay, and additionally a phosphorus component comprising organic phosphates and phosphine oxides - Google Patents

Abstract

Self-extinguishing extrudate made from a thermoplastic-polyurethane composition, comprises at least one polyurethane and an exfoliated nanoclay (0.1-15 wt.%), and additionally a phosphorus component comprising organic phosphates and phosphine oxides (0.1-20 wt.%). An independent claim is also included for the production of extrudate, comprising co-extruding the polyurethane together with the phosphorus component and the nanoclay, exfoliating the nanoclay and introducing the polyurethane and phosphorus component between the layers of the exfoliated nanoclay.

Description

The following invention relates to a self-extinguishing extrudate of a thermoplastic polyurethane composition and a process for its preparation.

Thermoplastic polyurethanes (TPU) are of great industrial importance because of their good elastomer properties and thermoplastic processability. They are also characterized by excellent chemical resistance and by very favorable mechanical properties such as elasticity, high elongation or good abrasion resistance. An overview of the production, properties and applications of thermoplastic polyurethanes is z. Eg in the Kunststoff Handbuch [ G. Becker, D. Braun], Volume 7; "Polyurethane", Munich, Vienna, Carl Hanser Verlag, 1983 given.

When using TPU in the field of electrics / electronics, especially when used for cables, high requirements must be met, which result in particular from the fact that the TPU should have a good flame resistance; in particular, since cables often use flammable, non-flame retardant polyolefin such as polypropylene, which should desirably be quenched by a self-extinguishing TPU. Combined with the task of using well-extruded TPUs with thin wall thickness, this task is very difficult with the known TPU materials.

Thus, the known TPU flame retardants are added, for example halogen-containing compounds. The addition of these compounds, however, often has a negative effect on the mechanical properties of the resulting TPU molding compositions.

Existing functioning flame retardant systems for TPU consist of a combination of brominated or halogenated organic substances and antimony oxides. Both are toxic to a considerable degree or toxic products may be produced in the event of a combustion process. In addition, halogen-containing organic compounds disadvantageously have a corrosive effect. Halogen-free self-extinguishing molding compounds are, for example, in EP 0 617 079 B2 and WO 2009 / 103765A1 and patents cited therein.

So revealed the EP 0 617 079 B2 a self-extinguishing thermoplastic polyurethane without halogen-containing flame retardant that extinguishes after ignition in a few seconds non-burning and does not drip and also has good mechanical and processing properties. The polyurethane contains as flame retardants a combination of an organic phosphate and / or phosphonate and a melamine cyanurate, wherein the polyurethane is obtained by polyaddition in the presence of the flame retardant.

The flameproof mixture of WO 2009 / 103765A1 contains, in addition to a polyurethane component, a flame retardant and a crosslinking agent dissolved in the polyurethane. Among the large number of listed flame retardants are, inter alia, phosphorus compounds such as organic phosphinate and phosphate compounds and clay and montmorillonite clay. The polyurethane added with the flame retardant should have the same good mechanical properties as a polyurethane without a flame retardant, which is used in an amount of from 20 to 70% by weight, based on the total mass.

The use of phosphorus and its compounds as flame retardants is known, with phosphorus being unfavorable to use because of its toxicity. It is more favorable to use inorganic phosphates, organic phosphates (OPOR ₃ ) or phosphine oxides (OPR ₃ ), the inorganic phosphates having the disadvantage of the described filler effect and organic phosphates (OPOR ₃ ) or phosphine oxides (OPR ₃ ) having to be metered high to ensure effective flame retardancy in TPU. In addition, they tend to migrate from the TPU matrix to the surface and form an undesirable deposit there. In addition, they have an adverse effect on the mechanical properties of the TPU molding compounds due to the necessary high dosage.

The use of Nanoclays as a filler to improve the mechanical properties of plastics or in general of polymeric materials is known. This describes the EP 1 581 588 B1 a modified nanoclay composition of a swellable inorganic layer material, which is evenly distributed in a polymeric material.

Furthermore, from the WO2005 / 111154 A2 a method for conditioning a layered silicate, in particular illite, to produce a nanoproduct by means of which the flow properties of plastics can be modified and controlled. Disagglomerated sheet silicate particles are obtained which can be incorporated into a plastic matrix by suitable processing. Such nanoclay fillers are usually added in concentrations between 5% and 15% to the plastics in order to influence their mechanical and rheological properties.

Based on this prior art, the object of the present invention is to provide a self-extinguishing extrudate of a thermoplastic polyurethane composition (TPU composition), the flame retardant component of which is halogen-free and effects self-extinction of the composition. Once ignited, the extrudate should have only a slight dripping tendency. The extrudate should also be easy to process and have good flowability during processing. The known advantageous mechanical and chemical properties of the polyurethane, however, should be optimally maintained despite Flammschutzzusatz.

This object is achieved by a self-extinguishing extrudate of a thermoplastic polyurethane composition having the features of independent claim 1.

It is also an object of the invention to provide a process suitable for making this self-extinguishing extrudate from the thermoplastic polyurethane composition. This object is achieved by a method having the features of claim 6.

Further developments of the device and the method are described by the subclaims.

A self-extinguishing extrudate of a thermoplastic polyurethane composition according to the invention contains at least one polyurethane and one exfoliated nanoclay in the composition. A first embodiment of the self-extinguishing extrudate according to the invention refers to the composition further containing a phosphorus component in a proportion of 0.1 to 20% by weight, based on a total weight of the polyurethane composition. This phosphorus component may comprise an organic phosphate, a phosphine oxide or a combination thereof. The proportion of the nanoclay in the composition is in a range of 0.1 to 15% by weight, based on the total weight of the polyurethane composition.

With this composition, which on the one hand contains a component which influences the rheology of the plastic with the nanoclay and on the other hand contains an effective but small amount of an organic phosphate or a phosphine oxide as flameproofing component, it is advantageous to provide an extrudate which is self-extinguishing in the case of ignition. dries off non-burning and at the same time has the desired mechanical and chemical properties of a polyurethane without additives. Furthermore, the extrudate composition according to the invention allows a good processability by a sufficient flow behavior, which advantageously also in the extrusion, the formation of a nozzle whisk is avoided, which otherwise arises when using organic phosphate or phosphine oxide with high levels as a flame retardant.

It was surprisingly found and in no way foreseeable that a self-extinguishing TPU extrudate can be obtained by the combination of organic phosphates or phosphine oxides with a small proportion of nanoclays, which are optimally dispersed as a result of the extrusion, which also very good mechanical and has processing and application properties. A synergistic effect of the use of phosphorus component and nanoclay allows a significantly lower dosage of both components, so that by the reduced amount of nanoclay filler and the flame retardant significantly more favorable mechanical properties can be achieved than with compositions that achieve a substantially higher flame retardancy Require proportion of phosphorus component. Furthermore, a migration of flameproofing components to the polymer surface is advantageously reduced or prevented.

The nanoclay used in the composition according to the invention may be an organically intercalated smectite. Among the smectites, an organically intercalated montmorillonite is preferred. Its content may be in a range of 0.1 to 10% by weight, and more preferably, it may be reduced to be in a range of 1 to 5% by weight based on the total weight of the polyurethane composition. If a ground illite is used as nanoclay, its proportion may be from 0.1 to 15% by weight, Advantageously, the illite nanoclay content in a range of 1 to 6 wt .-%, to be selected, each based on the total weight of the polyurethane composition.

The proportion of the phosphorus component can be reduced to a proportion of 1 to 12 wt .-%, based on the total weight of the polyurethane composition due to the synergy effect with the nanoclay.

The low filling levels of the Nanoclays ensure that the chemical resistance and the mechanical properties of the extrudate do not change adversely, and despite the lower flame retardant content, sufficient flameproofing can be achieved.

wobei R¹ für ein Wasserstoffatom, ein verzweigter oder unverzweigter Alkylrest mit 1 bis 12 C-Atomen, ein substituierter oder ein nicht-substituierter Arylrest mit 6 bis 20 C-Atomen, ein substituierter oder nicht-substituierter Aralkylreste mit 6 bis 30 C-Atomen oder ein substituierter oder nicht-substituierter Alkarylreste mit 6 bis 30 C-Atomen steht. R² und R³ sind jeweils unabhängig voneinander ein verzweigter oder unverzweigter Alkylenrest mit 1 bis 24 C-Atomen oder ein substituierter oder nicht-substituierter Alkarylenrest mit 6 bis 30 C-Atomen.As a phosphorus component, in one embodiment of the invention, a phosphine oxide can be selected which has the general formula O = P (R) ₃ and a number average molecular weight Mn of 60 to 1000. In particular, the phosphine oxide may be a phosphine oxide of the formula (I),

where R ^{1 is} a hydrogen atom, a branched or unbranched alkyl radical having 1 to 12 C atoms, a substituted or a non-substituted aryl radical having 6 to 20 C atoms, a substituted or unsubstituted aralkyl radicals having 6 to 30 C atoms or a substituted or unsubstituted alkaryl having 6 to 30 carbon atoms. R ² and R ³ are each independently a branched or unbranched alkylene radical having 1 to 24 carbon atoms or a substituted or unsubstituted alkarylene radical having 6 to 30 carbon atoms.

gewählt werden, wobei R¹, R², R³, R⁴ und R⁵ jeweils unabhängig voneinander ein verzweigter oder unverzweigter Alkylenrest mit 1 bis 24 C-Atomen oder ein substituierter oder nicht-substituierter Alkarylenrest mit 6 bis 30 C-Atomen sind.As an alternative to the phosphine oxide, as the phosphorus component, an organic phosphate having the formula (II) or (III)

R ¹ , R ² , R ³ , R ⁴ and R ^{5 are} each independently a branched or unbranched alkylene radical having 1 to 24 carbon atoms or a substituted or unsubstituted alkarylene radical having 6 to 30 carbon atoms.

One embodiment of a process for producing a self-extinguishing extrudate according to the invention relates to the step of co-extruding the polyurethane together with the phosphorus component and the nanoclay, wherein during extrusion the nanoclays are exfoliated and dispersed optimally in the extrudate, and polyurethane and phosphorus component between the exfoliated layers Nanoclays penetrate.

Another embodiment of the method according to the invention relates to the preparation of a pre-compound in which the phosphorus component is compounded in advance with the polyurethane before the extrudate is produced in the extruding step with the nanoclay.

In the preparation of such a pre-compound, the use of a "incorporable" phosphine oxide as the phosphorus component may be advantageous, which is condensed into the polyurethane.

Furthermore, an extrudate according to the invention can be produced by first extruding a masterbatch whose composition has a relatively increased proportion of the nanoclay with respect to the composition of the self-extinguishing extrudate. If appropriate, the proportion of the phosphorus component can also be correspondingly increased, with complete exfoliation of the nanoclay by extruding the masterbatch.

This masterbatch can then be coextruded with the polyurethane and optionally a portion of the phosphorus component in a further process step according to the invention, so that the self-extinguishing extrudate is obtained in the desired polyurethane composition.

The reference to the figures in the description is for the improved understanding of the subject matter and the support of the description. It shows:

1 the atomic structure of two layers of a phyllosilicate,

2 a schematic cross-sectional view of a twin-screw extruder.

Basically, the extrudate according to the invention refers to a polyurethane composition which is self-extinguishing and does not drip in the event of fire in the form of molten molding material burning, and thus meets the requirements, for example, the flame retardant test to UL 94 VO.

The inventively low levels of both nanoclay and the flame retardant organic phosphate and / or phosphine oxide allow the preparation of the self-extinguishing extrudate without deterioration of the mechanical properties by the disturbance of the polymer matrix. Also, the media resistance of the TPU is not degraded while maintaining good workability due to sufficient fluidity, which is in the known systems with the high concentrations of organic (melamine or melamine cyanurate) or inorganic (talc, metal hydroxides, chalk, clays) fillers not possible.

So far, when using phosphorus compounds in the form of inorganic phosphates, organic phosphates or phosphine oxides on the one hand, the disadvantageous filler effect of the former, on the other hand, the high dosage of the latter, to ensure effective flame retardancy in TPU. Furthermore, there has hitherto been the problem that these phosphorus compounds migrate from the polyurethane matrix to the surface where they form an undesirable deposit. This is prevented by the extrudate according to the invention which contains an effective but minimal amount of organic phosphate or phosphine oxide.

The use of phyllosilicates / sheet silicates to control the rheology of liquids is known. Swellable three-layer silicates of the smectite group, which comprises montmorillonite, or three-layer silicates without swelling capability of the mica-illite group can be used. By intercalation (in the case of montmorillonite), the original montmorillonite structure is lost or by suitable milling of illite (see WO2005 / 111154 A2 ) layer platelets are released in the nano range. Due to the intercalation, ie incorporation of polymers or generally long-chain ions or other charged particles into the intermediate layers, real networks are created.

In order to be able to use the intercalated Nanoclays technically, they must be exfoliated using further swelling agents. In this exfoliation, the original order in the phyllosilicates is lost; layers with a diameter of about 1000 nm and a length of 500-100 nm are obtained. These materials, known as nanoclays, obtained by the exfoliation of montmorillonite or by the milling of illite, have completely different properties from the raw clay minerals in the original state, which also influences their properties in the plastics they are fundamentally different from the influence of the original minerals.

Other suitable phyllosilicates are the three-layer silicates of the illite type calculated from the mica. By appropriate treatment / grinding of natural illite, described in WO2005 / 111154 A2 deagglomerated sheet silicate particles are obtained, which can be incorporated as nanoclay according to the invention in the polyurethane matrix together with the flame retardant organic phosphate or phosphine oxide.

For safe flame retardancy, good mechanical properties and good resistance to chemicals as well as the advantageous processability in terms of flow behavior and "beard" too obtained complete exfoliation of the sheet silicates in the thermoplastic polyurethane composition with the flame retardant during compounding in the extrusion process.

The structure of a monoclinic montmorillonite suitable for the formation of the nanoclays is in 1 shown. In general, layer silicates or phyllosilicates have the basic structural unit typical for silicates, the SiO ₄ tetrahedron, which are crosslinked to one another in layers having the composition Si ₂ O ₅ . In the three-layer silicate montmorillonite, two of these tetrahedral layers surround an octahedral layer in which a cation, here aluminum, but also conceivable magnesium, is surrounded octahedrally by hydroxide or oxygen.

Among the three-layer minerals are mainly montmorillonite from the smectite group, but also the mica / illite group.

The smectites are so-called layer silicates, which have a three-layer structure and belong to the clay minerals. The two tetrahedral layers of the three-layered smectites are electrostatically crosslinked via the cations of the octahedral intermediate layer. The layers are not rigidly connected, but can swell by reversible storage of water and other substances.

Between the two three-layer structures of the monoclinic montmorillonite (Al ₂ [(OH) ₂ / Si ₄ O ₁₀ ] .nH ₂ O) exists, in 1 indicated by the double arrow, a layer spacing of 1 to 2 nm. In between, water molecules and exchangeable cations are embedded. Due to the widening of the layer distances, organically intercalated phyllosilicates are obtained in which the montmorillonite structure is lost as a result of the layer expansion, since the layer spacings are now significantly greater and allow the incorporation of polymer molecules between the three-layer structures.

Illit is another three-layer clay mineral with an aluminum octahedron layer and two surrounding silicate tetrahedral layers. Illites are formed mainly from smectites (swelling clay minerals) by the incorporation of potassium ions between the layers during the diagenesis of sediments and have the empirical formula K _0.65 Al _2.0 Al _0.65 Si _3.35 O ₁₀ (OH).

Organically intercalated phyllosilicates are commercially available, such as the nanoclay Nanofil ^® SE 3000 (erhältl. Rockwood Clay Aditives GmbH). These nanoclays are derived from montmorillonites that are organically intercalated with distearoyldimethyl ammonium chloride. Nanofil ^® SE3000 is preferably used in a proportion of 0.1 to 10, preferably 1 to 5 wt .-%, based on the total weight of the polyurethane composition, are used.

As a further nanoclay raw material can serve a deagglomerierter illite with a fineness of <2 microns. In this case (f. Mining and minerals mbH Co. KG erhältl. B + M Nottenkämper Ges. U.), For example Arginotec NX ^® be used. Arginotec ^® NX is preferably used in a proportion of 0.1 to 15%, preferably 1 to 6 wt .-%, based on the total weight of the polyurethane composition, are used.

In principle, all known thermoplastic polyurethanes which can be prepared by processes known to the person skilled in the art are suitable for the self-extinguishing extrudate according to the invention.

ist R¹ = H, ein verzweigter oder unverzweigter Alkylrest mit 1 bis 12 C-Atomen, ein substituierter oder nicht-substituierter Arylrest mit 6 bis 20 C-Atomen, ein substituierter oder nicht-substituierter Aralkylrest mit 6 bis 30 C-Atomen oder ein substituierter oder nicht-substituierter Alkarylrest mit 6 bis 30 C-Atomen. R² und R³ bestehen jeweils aus einem verzweigten oder unverzweigten Alkylenrest mit 1 bis 24 C-Atomen oder einem substituierten oder nicht-substituierten Alkarylenrest mit 6 bis 30 C-Atomen, wobei R² und R³ gleich oder verschieden sein können. Das Phosphinoxid kommt vorzugsweise in einer Menge von 0,1 bis 20, bevorzugt 1 bis 12, Gew.-%, zum Einsatz.The incorporable as a flame retardant component phosphine oxide of the general formula O = P (R) ₃ , and more particularly of the formula (I) (according to EP 1 927 608 ) has on average at least 1.5 and at most 3.0, preferably 1.8 to 2.5, particularly preferably 1.95 to 2.10, Zerewitinoff-active hydrogen atoms. These Zerewitinoff-active hydrogen atoms are preferably contained in hydroxyl and amine groups of alcohols or amines. The phosphine oxide has a number average molecular weight Mn of 60 to 1000. In the preferred phosphine oxide of the general formula (I)

R ^{1 is} H, a branched or unbranched alkyl radical having 1 to 12 C atoms, a substituted or unsubstituted aryl radical having 6 to 20 C atoms, a substituted or unsubstituted aralkyl radical having 6 to 30 C atoms or substituted or unsubstituted alkaryl radical having 6 to 30 carbon atoms. R ² and R ³ each consist of a branched or unbranched alkylene radical having 1 to 24 carbon atoms or a substituted or unsubstituted alkarylene radical having 6 to 30 carbon atoms, wherein R ² and R ^{3 may be the} same or different. The phosphine oxide is preferably used in an amount of 0.1 to 20, preferably 1 to 12, wt .-%, are used.

wobei R¹, R², R³, R⁴, R⁵ ein verzweigter oder unverzweigter Alkylenrest mit 1 bis 24 C-Atomen oder ein substituierter oder nicht-substituierter Alkarylenrest mit 6 bis 30 C-Atomen sein können. R¹, R², R³ und R⁴ können dabei gleich oder verschieden sein. Die organischen Phosphate kommen vorzugsweise mit einem Anteil von 0,1 bis 20, bevorzugt von 1 bis 12, Gew.-%, bezogen auf das Gesamtgewicht der Polyurethan-Zusammensetzung, zum Einsatz.Unincorporatable organic phosphates are compounds of the general formulas (II) and (III)

where R ¹ , R ² , R ³ , R ⁴ , R ^{5 can be} a branched or unbranched alkylene radical having 1 to 24 carbon atoms or a substituted or unsubstituted alkarylene radical having 6 to 30 carbon atoms. R ¹ , R ² , R ³ and R ⁴ may be the same or different. The organic phosphates are preferably used in an amount of from 0.1 to 20, preferably from 1 to 12,% by weight, based on the total weight of the polyurethane composition.

By combining the nanoclays in small amounts and organic phosphates or incorporable phosphine oxides, which are optimally dispersed by co-extrusion in the polyurethane, the self-extinguishing TPU molding compounds are obtained as an extrudate.

Here, the Nanoclays are exfoliated in the polymer matrix in a ready-to-use formulation for controlling the flow behavior by means of extrusion in a twin-screw extruder together with the flame retardant phosphine oxide (I) or organophosphate (II), (III). Alternatively, the nanoclays can be processed in an exfoliation step together with part of the phosphorus compounds (I), (II) or (III) in the polymer matrix to form a masterbatch. In this exfoliation step by the extrusion, it is crucial that the silicate layers already expanded by the organic intercalation are completely exfoliated, ie that the polyurethane and the selected flame retardant (I), (II) or (III) are interposed between the three-layer structures. This creates a three-dimensional structure that makes flow of composition difficult at slow flow rates, but flows faster at higher shear rates.

The exfoliation of the nanoclays does not necessarily have to take place in the concentration required for the ready-to-use formulation; for the preparation of the masterbatch, a significantly higher concentration can be used as a source for the nanoclays to form the three-dimensional structure. It is crucial that even in the masterbatch, the layers of phyllosilicates are almost completely separated from each other.

In general, a pre-compound of polyurethane with a phosphorus component, also for providing a masterbatch, can be used to produce the extrudate according to the invention. For this Pre-compounding, the polyurethane is pre-equipped with the phosphorus component, such as a phosphine oxide, by prior compounding. This can either be done in the production of the polyurethane by the use of special phosphine oxides or alternatively by a separate compounding step in which the phosphine oxide is added to the polyurethane. During processing, this pre-compound is added with the necessary amount of intercalated and exfoliated nanoclays.

The coextrusion of the polyurethane with the exfoliated phyllosilicates (or ground illites) in combination with organophosphate / phosphine oxide synergistically complements their flame retardancy, good processability and good material properties, and provides the extrudate of the thermoplastic polyurethane composition.

The extrudate according to the invention can basically be produced in three different ways: using a masterbatch with polyurethane exfoliated nanoclay, a compound with condensed phosphine oxide and polyurethane exfoliated nanoclay or a compound with organic phosphate and polyurethane exfoliated nanoclay.

A compound is a mixture of unmixed raw materials to which additional fillers, reinforcing agents or other additives have been added.

The term masterbatch is understood here to mean a polyurethane whose content of additives, at least the content of nanoclays, is higher than in the end use. The content of the additive or nanoclays is increased as much as possible and as little polymer as possible is used. By using a masterbatch, process reliability can be increased, and masterbatches are very easy to process.

The invention will now be illustrated by way of examples. The examples do not limit the scope of the claimed invention.

The production of compounds and masterbatch is basically carried out by means of a corotating twin-screw extruder. A twin-screw extruder 10 is in 2 outlined. The ratio of length to diameter LID should be at least 44. The speed of the extruder should be as high as possible, but not above 1200 rpm. It is advantageous to use an extruder with high torque capacity.

A suitable extruder may also have connections to multiple backside degasifiers and vacuum degassing and the possibility of gravimetric dosing. Furthermore, a device for liquid metering can be provided with an injection pressure of more than 120 bar. At the extruder outlet devices may be arranged for strand granulation or for a head tee, after which a drying device can follow.

The arrangement and selection of the Scheckenelemente is selected as in a well-known in the art application with high filler contents and high dispersing performance. Conveniently, kneading elements and conveying elements are alternately used.

The total amount of the thermoplastic polyurethane is in each case in the transmission side first housing 1 metered by using a gravimetrically controlled dosage. The powdered components are also by means of gravimetric dosing in housing 1 or side dosing 2 or dosed distributed over several side dosages. Liquid components are introduced into the closed housing by means of a screw pump 5 dosed.

All raw materials used are carefully dried before use.

Example 1: Production process by means of masterbatch

The TPU molding compound is produced from a masterbatch, in which the nanoclay particles are prepared ready for use, that is, completely exfoliated. The masterbatch is processed directly with a pre-compounded ether TPU that already contains organic phosphates.

In a high speed mixer 15 kg Nanofil ^® 3000 are mixed with 1 kg (2-methylphenyl) diphenyl phosphate (KDP Disflamoll ^® Fa. Lanxess) mixed until the temperature has risen to 60 ° C, and then cooled. A compound of the mixture thus obtained 1 with humidity is avoided.

Desmopan ^® 9385 will be in the gearbox first housing in a quantity of 120 kg / h 1 of a Steer Omega 60 co-rotating twin-screw extruder. In the case 4 becomes by gravimetric side dosing 20% of the mixture described above 1 continuously metered, housing 3 serves as a degassing. In case 6 another 20% Nanofil ^® SE 3000 is metered in by means of gravimetric side dosing. The compound is extruded at a rate of about 170 kg / h at a speed of 600 rpm.

Table 1 gives the temperatures in the successive heating zones of the extruder together with the respective kneading (K) or conveying (F) process: heating zone 1 2 3 4 5 6 7 8th 9 10 T (° C) 70 190 200 210 215 215 210 200 200 190 F K F K F K K F K F / D Table 1

At heating zone 10 is connected to the promotion of the exit nozzle of Extrudes.

The hot melt is withdrawn from the nozzle plate as strands, this cooled in a water bath, then worked up with granules to a granulator and dried by means of a blow dryer to a moisture content of less than 0.02%.

The masterbatch thus obtained is mixed with a pre-compound of 7% organophosphate gem. (II) and Desmopan ^® 9385 processed to produce test specimens. For the preparation of this pre-compound Desmopan ^® 9385 with a quantity of 16 kg / h in the gearbox first housing 1 of a co-rotating twin-screw extruder from Werner and Pfleiderer ZSK30.

The housing 3 serves the degassing. In case 6 by means of a screw-rotor pump through a valve, a proportion of 7 wt .-% liquid (2-methylphenyl) diphenylphosphats metered with a Temperature profile according to Table 2 (Disflamoll ^®, DPK Lanxess.): heating zone 1 2 3 4 5 6 7 temperature 70 ° C 200 ° C 220 ° C 245 ° C 245 ° C 240 ° C 230 ° C F F K F K F F / D Table 2

The hot melt is withdrawn from a two-hole nozzle as a strand, cooled in a water bath and then worked up to granules with a strand granulator. The extrudate is extruded at a rate of about 18 kg / h at a speed of 220 rpm.

Example 2: Production process by means of compound

First, the compounding of the individual components of a commercial ether TPU molding compound such. B. Desmopan ^® 9385 are added, wherein in the compounding the complete exfoliation of the nanoclays takes place.

Desmopan ^® 9385 is in a quantity of 16 kg / h in the transmission side first housing 1 of a co-rotating twin-screw extruder from Werner and Pfleiderer ZSK30. 4% phyllosilicate powder Nanofil ^® SE 3000 is continuously metered into the same housing by means of gravimetric dosing. The housing 3 serves for degassing. In case 6 is by means of a screw pump via a valve, a proportion of 10 wt .-% liquid (2-methylphenyl) diphenylphosphats (Disflamoll ^® , DPK Fa. Lanxess) added. The temperature profile of the seven heating zones and the respective kneading (K) or conveying (F) process are listed in Table 2. The hot melt is withdrawn after the last heating zone 7 from a two-hole nozzle (D) as strand, cooled in a water bath and then worked up with a strand granulator to granules. The compound is extruded at a rate of about 18 kg / h at a speed of 220 rpm.

The properties of the granules formed from the extrudate were checked. A measurement of the MVR values (MVR = melt volume rate) of the granules was carried out according to ISO 1133 with 10 kg weight. A preparation of test specimens from the respective granules was carried out in a Boy 30 injection molding machine in which it was melted at a melt temperature of about 230 ° C and formed into test specimens.

The produced TPU granules could be processed by means of strip extrusion. It was melted in a single-screw extruder 30 / 25D (Plasticorder PL 2000-6, from Brabender) in a dosage of 3 kg / h at a temperature of 230 to 195 ° C and extruded through a slot die into a ribbon. A mechanical test at room temperature included tear strength (σ) and elongation at break (ε), which after the injection moldings DIN 53 405 were measured.

The flame retardancy was determined according to UL94 V at a specimen thickness of 3 mm (after: Underwriters Laboratories Inc. Standard of Safety, "Test for Flammability of Plastic Materials for Parts in Devices and Appliances", p 14 ff, Northbrook 1998 and J. Triotzsch, "International Plastics Flammability Handbook", p 346 ff, Hanser Verlag, Munich 1990 ).

In this test, a rating with V-0 means a non-burning drip. A product with this rating is therefore referred to as flame retardant. A V-2 rating means burning dripping, ie lack of flame retardancy. example MVR 210 ° C σ (MPa) ε (%) extrusion quality UL-94 0 Desmopan ^® 9385 43 517 Good, homogeneous, no coating no nozzle deposits 1 Extrudate of masterbatch and TPU compound 40 44 410 Good, homogeneous, no coating no nozzle deposits V-0 2 Extrudate from direct compounding 40 41 464 Good, homogeneous, no coating no nozzle deposits V-0

The comparison with the TPU molding composition Desmopan ^® 9385 without the invention added combination of nanoclays and organophosphate / phosphine clearly shows that according to the invention extruded flameproof TPU molding compositions are obtained having good mechanical properties and good processability, independently on the preparation according to Example 1 or 2 when the combination according to the invention of thermoplastic polyurethane with exfoliated nanoclays and organic phosphorus derivatives can be used as the flameproofing component.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0617079 B2 [0005, 0006]
• WO 2009/103765 A1 [0005, 0007]
• EP 1581588 B1 [0009]
• WO 2005/111154 A2 [0010, 0034, 0036]
• EP 1927608 [0046]

Cited non-patent literature

• G. Becker, D. Braun], Volume 7; "Polyurethane", Munich, Vienna, Carl Hanser Verlag, 1983 [0002]
• ISO 1133 [0073]
• DIN 53 405 [0074]
• Underwriters Laboratories, Inc. Standard of Safety, "Test for Flammability of Plastic Materials for Parts in Devices and Appliances", p 14 ff, Northbrook 1998 [0075]
• J. Triotzsch, "International Plastics Flammability Handbook", p 346 ff, Hanser Verlag, Munich 1990 [0075]

Claims (10)

A self-extinguishing extrudate of a thermoplastic polyurethane composition, wherein at least one polyurethane and an exfoliated nanoclay are included in the composition, characterized in that the composition further contains a phosphorus component from the group comprising organic phosphates and phosphine oxides, wherein the phosphorus component is present in an amount from 0.1 to 20 wt .-%, based on a total weight of the polyurethane composition, is present, and wherein the nanoclay is present in a proportion of 0.1 to 15 wt .-%, based on the total weight of the polyurethane composition , Extrudate according to claim 1, characterized in that the nanoclay An organically intercalated smectite, in particular an organically intercalated montmorillonite, the proportion of which is from 0.1 to 10% by weight, preferably from 1 to 5% by weight, based on the total weight of the polyurethane composition, or - Is a ground illite, the proportion of from 0.1 to 15 wt .-%, preferably from 1 to 6 wt .-%, based on the total weight of the polyurethane composition. Extrudate according to claim 1 or 2, characterized in that the proportion of the phosphorus component of 1 to 12 wt .-%, based on the total weight of the polyurethane composition is. Extrudate according to at least one of claims 1 to 3, characterized in that the phosphorus component is a phosphine oxide of the general formula O = P (R) ₃ having a number average molecular weight Mn of 60 to 1000 and preferably the formula (I)

wherein R ^{1 is} a hydrogen, a branched or unbranched alkyl radical having 1 to 12 C atoms, a substituted or unsubstituted aryl radical having 6 to 20 C atoms, a substituted or unsubstituted aralkyl radical having 6 to 30 C Or R ² , R ^{3 are} each independently a branched or unbranched alkylene radical having 1 to 24 carbon atoms or a substituted or unsubstituted alkarylene radical with 6 to 30 C atoms are. Extrudate according to at least one of claims 1 to 3, characterized in that the phosphorus component is an organic phosphate having the formula (II) or (III)

is, where R ¹ , R ² , R ³ , R ⁴ , R ^{5 are} each independently a branched or unbranched alkylene radical having 1 to 24 carbon atoms or a substituted or unsubstituted alkarylene radical having 6 to 30 carbon atoms. A process for producing a self-extinguishing extrudate according to at least one of claims 1 to 5, comprising the steps - Coextruding the polyurethane together with the phosphorus component and the nanoclay, wherein exfoliation of the nanoclay and introduction of polyurethane and phosphorus component between the layers of the exfoliated nanoclay occurs. The method of claim 6, comprising the step - Providing a pre-compound of the polyurethane and the phosphorus component before coextruding with the nanoclay. The method of claim 7, comprising the step When using a phosphine oxide as the phosphorus component to provide the pre-compound, the phosphine oxide condenses into the polyurethane. Method according to at least one of claims 6 to 8, comprising the step By a first coextrusion, providing a masterbatch comprising a masterbatch composition comprising at least one polyurethane and a nanoclay of the polyurethane composition, wherein a masterbatch fraction of the nanoclay is increased compared to the fraction of the nanoclay in the polyurethane composition. The method of claim 9, comprising the step Coextruding the masterbatch together with the polyurethane and the phosphorus component and obtaining the self-extinguishing extrudate with the polyurethane composition.

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