EP1622982A1

EP1622982A1 - Polymer-nanocomposite blends

Info

Publication number: EP1622982A1
Application number: EP04725286A
Authority: EP
Inventors: Daniela Tomova; Stefan Reinemann
Original assignee: DOMO Caproleuna GmbH; Sued Chemie AG
Current assignee: DOMO Caproleuna GmbH; Sued Chemie AG
Priority date: 2003-05-05
Filing date: 2004-04-02
Publication date: 2006-02-08
Also published as: US20070004842A1; JP2006525383A; WO2004099316A1

Abstract

The invention relates to polymer-nanocomposite blends comprising at least two polymers and layered silicates which are delaminated in a nanodispersed manner and have advantageous properties. Also disclosed are methods for the production thereof. The inventive polymer-nanocomposite blends contain: a) 55 to 95 percent by weight of polyamide (PA); b) 4 to 40 percent by weight of polypropylene (PP); c) 1 to 9 percent by weight of nanodispersed layered silicates; and d) up to 10 percent by weight of carboxylated polyolefins, particularly ethylene copolymers comprising unsaturated carbonic acids, such that the percentage by weight of the respective compositions is always 100 percent. Optionally, common stabilizers and fillers can be added. The inventive nanocomposite blends are characterized by great stiffness in the freshly injected and conditioned state, reduced water absorption, improved thermooxidative stability, and no reduction of toughness.

Description

description

Polymer nanocomposite blends

The invention relates to polymer-nanocomposite blends composed of at least two polymers and nanodispersed delaminated layered silicates. The layered silicate is a modified natural sodium montmorillonite, hectorite, bentonite or synthetic mica. The invention also relates to a method for producing these nanocomposites and their use. The object of the invention is to produce inexpensive polyamide-based nanocomposites with improved properties, such as high rigidity even in the conditioned state and stability against thermal oxidation.

Nanocomposites based on polyamides but also on polyolefins are becoming more and more attractive compared to conventional composites with glass fibers or minerals because of the weight savings with the same property profile. Composites of this type are of interest for a wide range of uses for injection molded parts in automobile and aircraft construction, for electrical engineering and electronics, device technology and in medical technology. The improvement in properties is primarily due to the ability of the individual layers of the layered silicates to expand (intercalation) or to separate completely from one another (exfoliation). This creates an enlarged surface of the filler and also an enlarged interface with the matrix polymer in order to achieve intercalation or exfoliation in the production of polymer nanocomposites. Chen, the layered silicates are first modified with organic compounds by cation exchange, ie adjusted organophilic, and are also referred to as organoclays. Interactions or contact points with the matrix polymer are also necessary.

The incorporation of organically intercalated phyllosilicates into polymers by in-situ polymerization or via melt compounding is described in several patents and mostly associated with an improvement in the mechanical and barrier properties and the heat resistance [US4739007, WO0034180].

The in-situ polymerization of ε-caprolactam in the presence of organophilically modified clay was already described in 1988 [ÜS4739007]. The incorporation of organoclays in polyethylene terephthalate (PET) via melt compounding brought an improved barrier to oxygen [WO 0034180].

Polyamide nanocomposites with a second polymer component are also known in principle. The incorporation of brominated rubber [US6060549] or maleic anhydride-grafted polypropylene [X. Liu et al. Polymer 42, 2001, 8235-8239] in in-situ polymerized polyamide 6 / Na-montmorillonite nanocomposites led to an improvement in the impact resistance, but to a decrease in the mechanical strength of the polyamide. A reduced water absorption was also found depending on the PP-g-MA content in the mixture.

Polyamide composites with increased flexural modulus and dimensional stability during water absorption, but with the disadvantage of reduced toughness has also been described [EP1076077]. The co posites were compounded in the melt by means of a twin-screw extruder and contain 2-40% by weight of maleic anhydride-grafted ethylene butyl acrylate or maleic anhydride-grafted polypropylene and 0.3-30% by weight of triazine-modified synthetic layered silicate.

EP0352042 also describes polyamide nanocomposites with one or two further polymer components. For example, an in-situ polyamide nanocomposite was impact modified using melt compounding with an ethylene methacrylate Zn ⁺ ionomer. However, losses in strength and rigidity have been found.

In-situ polymerized polyamide 6 nanocomposites which were subsequently compounded in the melt with an impact modifier (butyl acrylate, methyl acrylate rubber or mixtures thereof) are described in DE19854170. The authors also claim the in-situ polymerization of PA 6 in the presence of organosilicate and the rubber component. With a clay content of 3.7% by weight and rubber content of 3% by weight, these composites showed a very high modulus of elasticity (5420 MPa), good impact strength (Charpy leü 112 kJ / m ² ), but a low elongation at break of 2.9%. The layered silicates used were modified with di-2-hydroxyethylmethylstearylamine.

In the patent US5206284 Polypropylencom- be ^* pounds claimed that a modified PP (PP-g-MA), a polyamide nanocomposite (MPA), which in situ with 2% Organoclay (aminododecanoic acid modified Motmorillonit) was produced, an ethylene-alpha-olefin rubber or a modified ethylene-alpha-olefin copolymer such as. B. EPR-g-MA or SEBS-g-MA contain. The composite PP-g-MA / PP / MPA in the weight ratio 30/10/60 showed a flexural modulus of 26000 kg / cm ² (2550 MPa), a flexural strength of 770 kg / cm ² (75 MPa), a yield stress of 450 kg / cm ² (45 MPa) and a heat distortion temperature HDT @ 0.45MPa of 150 ° C. The strength, stiffness and toughness decreased with an increase in the proportion of PP.

JP10279752 claims a composition consisting of 40-99.9% by weight of polyolefin grafted with carboxylic acid or anhydride, 0.5-40% by weight of polyamide and 0.01-20% by weight of layered silicate with an improved oxygen barrier.

By Tjong, S. C; Meng, Y. Z .; Xu, Y., [J. Applied Polymer Science (2002), 86 (9), 2330-2337] a clay modification by maleic anhydride was described for the production of PA δVPP-Vermiculite nanocomposites. PP and maleated vermiculite were first compounded in the melt and the mixture was subsequently processed together with PA 6 by injection molding. An increase in the tensile modulus from 995 MPa for the pure PA 6 to 1397 MPa in the nanocomposite with a PP / vermiculite content of 31% by weight (8% vermiculite) was observed, the strength remaining unchanged and the Elongation has decreased significantly.

Hua Wang et al. ["Processing and Properties of Polymeric Nano-Co posites" Polym. Closely. Be . 41, 11 (2001), 2036-

2046] have nylon 6 / PP blends with the addition of approx. % Clay examined. With these blends, a refinement of the blend morphology was observed by adding layered silicates using scanning electron microscopy. An increase in the modulus of elasticity, which is attributable to the excessively high proportion of clay, and a drastically reduced toughness were found. Compatibility with PP-g-MA led to a decrease in stiffness and had little positive impact on toughness.

Polyamides fulfill high-quality functions as fibers, films or components in the broadest sense. Due to the tendency to absorb water, the expansion is restricted to large fields of application. For example, PA 6 at 23 ° C and 50% humidity 3% water, at 100% relative humidity even up to 9.5%. As is known, the stored water has a significant impact on basic mechanical parameters.

It is known that in blends made of polyamide and polyolefins, the water absorption is reduced according to the polyolefin content [L. Bottenbruch, R. Binsack; Plastics Handbook; Carl Hanser Verlag, Munich 1998]. Compatibility with functionalized polyolefins such as Block or graft copolymers and the associated influence on the interfacial adhesion is generally indispensable.

However, this is also associated with disadvantages. The use of compatibilizers, such as functionalized polyolefins and copolymers, is usually associated with a plasticizer effect and leads to a decrease in strength and rigidity. Polyamides are also sensitive to high temperatures. It is known that polyamides are thermooxidatively damaged when stored in air, even below their melting point. The polyamides lose their physical properties depending on the storage time and temperature. This is also known as oven aging and is not associated with the thermal degradation that can occur at temperatures above the melting point. The property of polymers to maintain their mechanical strength, toughness, inter alia for a long time at high temperatures, is also called thermal stability, here also referred to as "thermal stability ¹ or" thermo-oxidative stability ". To improve the thermal stability of polyamides, heat stabilizers, Glass fibers and other polymers such as polyphenylene ether are used.

Most of the methods used to determine thermal properties such as HDT (HDT = Heat Deflection-Temperature) or DMTÄ (DMTA = Dynamic-Mechanical-Thermal Analysis) mainly provide information about the short-term resistance of materials at high temperatures. The time-dependent influence of thermal oxidation and the associated deterioration in properties cannot be satisfactorily recorded in this way. A statement about the thermal stability of polyamide nanocomposites has so far only been based on an HDT increase or the storage module at the corresponding temperature or a glass transition shift (DMTA measurement). The studies carried out here on long-term stability have shown that polyamide 6 / clay nanocomposites do not contribute to thermal stability after storage in air Have temperatures above 100 ° C. The thermal oxidation on the surface of the nanocomposite is much faster than polyamide itself, leading to rapidly decreasing strength and surface quality schä- ^• interred (see the properties of PA nanocomposites listed in Table 4).

The object of the present invention is to maintain the favorable properties of the polyamide, such as rigidity even in the conditioned state, and good thermo-oxidative stability in conjunction with a reduced density compared to conventional glass or mineral reinforcement, and to reduce costs compared to pure PA 6 / clay nanocomposites.

According to the invention, this is surprisingly achieved by polymer-nanocomposite blends which a) polyamide (PA) from 55 to 95% by weight, b) polypropylene (PP) from 4 to 40% by weight, c) nanodisperse layered silicates from 1 to 9% by weight. % d) (optionally) carboxylated polyolefins, in particular copolymers of ethylene with unsaturated carboxylic acids, up to 10% by weight, preferably 0.1 to 1.9% by weight, so that the corresponding compositions always have a weight ratio of 100% by weight. % result. If necessary, an addition of conventional stabilizers and fillers can be included.

Component a) polyamide

Polyamides are formed by a condensation reaction of lactams with a more than three-membered ring and / or ω-amino acid (s) or of at least one diacid and produced at least one diamine. The polyamide resins produced by polycondensation are polyamide polymers or copolymers. The polyamide resin is selected from the group consisting of homopolyamides, copolyamides and mixtures thereof, and these polyamides are either semi-crystalline or amorphous.

Examples of monomers are ε-caprolactam, ε-aminocaproic acid, 11-aminoundecanoic acid, 9-aminononanoic acid and piperidone. Examples of diacids include adipic acid, sebacic acid, dodecanedioic acid, glutaric acid, terephthalic acid, 2-methyl terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid. Examples of diamines are tetramethylene diamine, hexamethylene diamine, nona ethylene diamine, decamethylene diamine, ündecamethylene diamine, dodecamethylene diamine, p-aminoanilline and m-xylene diamine.

The polyamides are preferably selected from the group of polyamide (nylon) 6 or polyamide (nylon) 6/66 with 0 to 20% polyhexamethylene adipamide.

A polyamide 6 with a solution viscosity, measured in a 1% solution of 96% sulfuric acid at 23 ° C., from 2.2 to 4.0, preferably from 2.4, is particularly suitable for the polymer-nanocomposite blends according to the invention up to 3.5.

Component b) polypropylene

Homopolymers or statistical copolymers or block copolymers of propylene with one or more olefins, such as ethylene and linear, come as polypropylene and / or branched C ₄ - to C _i0 1 olefins, are used. Polypropylene homopolymers and block copolymers with a low ethylene content are expediently used.

As component b) a polypropylene with a melt index of 1 to 110, from 5 to 30 ccm / 10 min (230 ° C / 2.16 kg) is preferably used.

Component c) Nanodisperse layer silicates

A natural sodium montmorillonite, hectorite, bentonite or synthetic mica with a cation exchange capacity of 60 to 150 meq / 100 g is preferably used as the nanodisperse layered silicate.

Up to 5% by weight of nanodisperse layered silicates are preferably used. Compared to Hua Wang et al, they are characterized by high toughness, high rigidity in the spray-fresh and conditioned state, reduced water absorption and improved thermo-oxidative stability. There is a coexistence of two phases in the nanocomposite blends according to the invention, so that the organically intercalated layered silicates mainly disperse or exfoliate in the polyamide phase. An accumulation of exfoliated layers at the interface with the polypropylene phase could be observed by means of transmission electron microscopy (TEM) (Fig. 4). It is assumed that interactions between the polyamide and polypropylene phases are initiated by the organically intercalated and delaminated layered silicates. A delaminated layered silicate (nanoclay, organically intercalated) in the sense of the invention is to be understood as swellable layered silicates in which the layer spacings of the individual silicate layers have been increased by reaction with so-called hydrophobizing agents. In the case of montmorillonite, intercalation with suitable, preferably cationic, intercalation components leads to an interlayer spacing of 1.2 to 5.0 nm.

Layered silicates with a cation exchange capacity of at least 50, preferably 60-150 eq / 100 g are preferred. The alkali and alkaline earth metals which can be exchanged in these swellable layered silicates are partially or completely substituted by onium, ammonium, phosphonium or sulfonium ions in the sense of an ion exchange reaction. Swellable layered silicates in which 50 to 200% of the exchangeable inorganic cations have been replaced by organic cations are particularly preferred.

Cationic nitrogen compounds suitable for intercalation are alkylammonium ions such as laurylammonium, myristylammonium, palmitylammonium. Further preferred cationic nitrogen compounds are quaternary ammonium compounds such as, for example, distearyldimethylammonium chloride and dimethyldistearylbenzylammonium chloride.

In particular, ω-aminocarboxylic acids such as ω-aminoundecanoic acid, ω-aminododecanoic acid, ω-aminocaprylic acid or ω-aminocaproic acid can be used as bifunctional cationic nitrogen molecules. Further preferred nitrogen-containing intercalation components are caprolactam, lauryllactam, mela in and oligo ere water-soluble a ide.

All nitrogen-containing intercalation components are preferably used in protonated form. All water-soluble organic or inorganic acids are suitable for protonation. Mineral acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid, and also acetic acid, formic acid, oxalic acid and citric acid are preferred.

Suitable phosphonium include for example Do- cosyltrimethylphosphonium, xylphosphonium Hexatriacontyltricyclohe-, Octadecyltriethylphosphnium, Dicosyltrii- so-butylphosphonium, hexadecylphosphonium Methyltrinonylphosphonium, Ethyltri-, di-methyldidecylphosphonium, Diethyldioctadecylphosphonium, Octadecyldiethylallyl- phosphonium, Trioctylvinylbenzylphosphonium, Dioctydecy- lethylhydroxyethyl phosphonium, Docosyldiethyldichlorben- zylphosphonium, Octylnonyldecylpropargyl -phosphonium, triisobutylperfluorodecylphosphonium, Eicosyltrihydroxy-methyl-phosphonium, Triacontyltriscyanethylphosphonium and Bistrioctylethylenendiphosphoniu called.

Component d) carboxylated polyolefins

Suitable as component D are polyolefins, in particular polyolefin copolymers, which are functionalized with unsaturated mono- or dicarboxylic acids or anhydrides. They can be contained in the nanocomposite blends up to 10% by weight, preferably they are contained from 0.1 to 1.9% by weight. Particularly suitable are ethylene-ionomer copolymers, preferably ethylene-acrylic acid or ethylene-methacrylic acid copolymers, which are partially or completely neutralized with metal ions. The ethylene iono it can be a metal ion-containing ethylene-butadiene-acrylic acid copolymer, ethylene-methyl acrylate-maleic acid copolymer. The metal ion is preferably a Zn +, Na +, Mg +, or Zn-amine complex ion.

Other additives

The polymer nanocomposite blends according to the invention can optionally contain conventional stabilizers and fillers, selected from oxidation stabilizers, light stabilizers, process stabilizers, UV stabilizers, lubricants, release agents, pigments, dyes, flame retardants, fiber reinforcing fillers.

Examples of oxidation and process stabilizers are mixtures of at least two substances selected from metal halides, e.g. Sodium, potassium, lithium, zinc and copper halides or organic compounds based on phenol, hydroquinones, organic phosphite compounds.

Examples of UV stabilizers are resorzinols, salicylics, hindered amines, benzotriazoles and benzophenols.

Examples of "lubricants and release agents are stearic acid, stearic alcohol, stearic acid amide, waxes, carboxylic acid esters, carboxylic acid metal salts.

Examples of pigments are titanium dioxide, cadmium sulfide, cadmium selenite, ultramarine blue, carbon black.

The organic dye is, for example, nigrosine.

Examples of flame retardants are organic halogen compounds, organic phosphorus compounds, red phosphorus, metal hydroxides. Examples of fillers and reinforcing materials are glass fibers, glass beads, glass flakes, talc, carbon fibers, kaolin, wollastonite, molybdenum sulfide, potassium titanate, barium sulfate, electrically conductive carbon black and aramid fibers.

In addition, other additives such as magnetizing substances, EMI masking agents, antibacterial and antistatic agents can also be introduced.

The polymer nanocomposite blends are made by the components

a) polyamide (PA) from 55 to 95% by weight, b) polypropylene (PP) from 4 to 40% by weight, c) nanodisperse phyllosilicates from 1 to 9% by weight, d) carboxylated polyolefins, in particular copolymers of ethylene with unsaturated carboxylic acids, (from 0.0) to 10% by weight, preferably 0.1 to 1.9% by weight,

Contain, d e over this composition of a total of 100 wt.% of additives of conventional stabilizers and fillers can be compounded at temperatures above the melting temperatures of the polymers involved in an extruder or kneader.

One variant is that the components are compounded in one step.

Two-step processes are also possible. The components, c) and d) in parts of component a) can first be incorporated in the form of a masterbatch, and in the second step the masterbatch is compounded with component b) and the rest of component a) and processed further.

In another embodiment, components d) and b) are first compounded to a modified polypropylene in an extruder or kneader above the melting temperatures of the polymers involved, and component c) and part of component a) are incorporated in the form of a masterbatch, the masterbatch in the next step, compounded with the modified polypropylene and the rest of component a) and processed further.

It is also possible that components d) and b) are first compounded into a modified polypropylene in an extruder or kneader above the melting temperatures of the polymers involved, and the modified polypropylene is compounded in the next step with component a) and component d) and is processed further.

The polymer nanocomposite blends according to the invention are particularly suitable for use as extrudates, injection molded parts or fibers.

The intercalation components mentioned in the description of component c) act as water repellents and influence the surface tension of the layered silicates, so that the polarity and the total value of the 0- surface energy decrease. After compounding with polyamide, the polarity and surface tension of the polyamide decrease. This results in better mixing and finer dispersion of the polypropylene phase in the nanocomposite blends compared to pure PA 6 / PP blends.

The TEM examination on the PA 6 / PP nanocomposite blends according to the invention shows a fine dispersion of the polypropylene phase. The particles have a size between 0.1 and .1 μm (Figure 4a). In Figure 4b it can be seen that the exfoliated layered silicates are mainly dispersed within the polyamide matrix, whereby an attachment of the layers, which form a kind of card structure around the polypropylene particles, can clearly be seen. The increased concentration of the organophilic layered silicate at the interface between the polyamide and the polypropylene phase reduces the surface tension difference between the per se incompatible polymers.

The morphology in the nanocomposite blends (on gold-coated cryopractic surfaces) was also examined using scanning electron microscopy (SEM). Larger structures were also observed. In Figure 5a, the PP phase is distributed in the form of rods in the PA / PP nanocomposite blends. After adding only 1 to 1.9% by weight of ethylene ionomer, it is no longer possible to distinguish the PP from the PA phase. The cryopractic surface appears as a closed surface with an unbroken PA / Clay-PP interface. However, it can Small PP particles embedded in the polyamide / clay matrix with a diameter of less than 1 μm can be observed (Fig. 5b).

"The nanocomposite blends according to the invention show very good mechanical properties such as strength, rigidity and impact strength in the freshly injected and conditioned condition, but also after storage in temperature.

Compared to pure polyamide, the tensile modulus of elasticity is increased by up to 50% in the freshly molded state, in the conditioned state this increase is up to 150%. Compared to a correspondingly composed polyamide / polypropylene blend, this increase is up to 70% when freshly sprayed and more than 75% when conditioned. The water absorption of the described PA / PP nanocomposite blends after conditioning (for example at 23 ° C and 95% air humidity) is clearly below that of the pure nanocomposites and also of the pure polyamide 6. In the saturated state and after storage in water for more than 1800 Hours, the nanocomposite blends also show a 150% improvement in tensile modulus compared to pure polyamide.

After storage at temperatures above 100 ° C. (110, 120, 130 and 150 ° C.), the nanocomposite blends according to the invention show the least loss of mechanical strength.

After the addition of small amounts of in particular up to 1.9% by weight of ethylene ionomer, the nanocomposite blends according to the invention, in particular in the case of a never the molecular, completely neutralized with Zn ethylene ionomer and without the addition of a heat stabilizer, a significantly lower loss of mechanical strength after temperature storage at 150 ° C.

In addition to the thermal stability, these nanocomposite blends also showed reduced water absorption and significantly higher stiffness in the conditioned state according to ISO 1110 (50% relative humidity).

The storage module, measured in the torsion test, of the nanocomposite blends according to the invention with 15% by weight PP runs similarly to PA 6 nanocomposites in the temperature range from 25 to 150 ° C. and is up to 100% higher at a temperature of 100 ° C. from pure polyamide 6

(Fig. 6). In the nanocomposite blends according to the invention there is a slight decrease in the with increasing PP content

Determine storage module, which still runs above the storage module of pure polyamide 6 (Fig. 7).

The invention is illustrated by the following examples, without being limited thereto:

Examples 1 to 7 - One Step Process

PA / PP nanocomposite blends were produced using a twin-screw extruder (ZSK 25, Coperion Werner & Pfleiderer) with an L / D ratio of at least 40. The polymers and the organically intercalated layered silicates were metered in in the first zone using polymer or powder scales. The compounding was carried out at temperatures between 220 and 260 ° C and a speed of 400 min ^-1 . The compounded nanocomposite blends were processed into test specimens using injection molding (Arburg Allrounder 320M 850-210).

The distances between the silicate flakes were determined by means of WAXS analyzes (WAXS = wide-angle X-ray structure analysis). In conjunction with TEM imagery, conclusions could be drawn about the degree of exfoliation or the degree of dispersion of the layered silicates. The distribution of the polypropylene phase in the nanocomposite blends was assessed using TEM and REM images. (TEM = transmission electron microscopy; REM = scanning electron microscopy)

The volume melt indices of the starting components and of the nanocomposite blends were measured using a melt index tester (Göttfert company) and listed in the individual examples as a melt index.

The mechanical properties of the nanocomposite blends were freshly injected and conditioned in the tensile test

DIN EN ISO 527 and impact test according to DIN

EN ISO 179 / leA tested. Thermal stability (HDT) was measured according to ASTM D648. The conditioning of the samples in Examples 1 to 4 was carried out at a temperature of 23 ° C. and 95% moisture for a period of 280 hours (conditioning 1). A part of the samples was then tested in a tensile test and the remaining part was stored in water at room temperature until saturation (conditioning 2). The composition of the nanocomposite blends is shown in the individual examples. The properties are shown in Tables 1 to 4, the water absorption in Figures 1, 2 and the E-moduli in Figure 3.

The dynamic-mechanical behavior of the nanocomposite blends in Examples 6 and 7 was examined using a torsion tester RDA II (Rheometric Scientific) at constant elongation of 0.1% and a frequency of 1 Hz. The storage module depending on the temperature is shown in Figure 6.

The conditioning of samples 6 and 7 was carried out according to EN ISO 1110 at 70 ° C and 62% relative humidity up to constant weight. The test bars of the samples in Examples 6 and 7 were also stored in convection ovens at 110 ° C, 120 ° C, 130 ° C and 150 ° C and the properties were then determined in a tensile test.

The solution viscosity of polyamide 6 was measured in a 1% solution in sulfuric acid (96%) at 25 ° C. example 1

Polyamide 6 with a melt index of 4.9 (230 ° C / 2.16kg) and a relative solution viscosity of 3.45 (reference polyamide I), polypropylene with a melt index of 5 (230 ° C / 2.16kg) and octadecylamine Modified montmorillonite (eg Nanofil 848) was compounded in a weight ratio of 80/15/5.

Example 2 Polyamide 6 with a melt index of 4.9 (230 ° C / 2.16kg) and a relative solution viscosity of 3.45, polypropylene with a melt index of 5 (230 ° C / 2.16kg), octadecylamine-modified montmorillonite ( eg Nanofil 848) and aminododecanoic acid-modified montmorillonite (eg Nanofil 784) were compounded in a weight ratio of 79.2 / 15.8 / 2.5 / 2.5.

Comparative Example 3

Polyamide 6 with a melt index of 4.9 (230 ° C / 2, 16kg) and a relative solution viscosity of 3.45, polypropylene with a melt index of 5 (230 ° C / 2, 16kg) were compounded in a weight ratio of 85/15.

Comparative Example 4 Polyamide 6 with a melt index of 4.9 (230 ° C./2, 16 kg) and a relative solution viscosity of 3.45 and octadecylamine-modified montmorillonite (eg Nanofil 848) were compounded in a weight ratio of 96.8 / 3.2. The results are shown in the tables below. Table 1: Properties of the nanocomposite blends according to the invention

Table 2: Properties of the nanocomposite blends according to the invention after conditioning at 23 ° C. and 95% relative humidity for a period of 280 hours.

Table 3: Water absorption of the nanocomposite blends according to the invention after conditioning at 23 ° C. in water.

Example 5 polyamide 6 with a melt index of 22.3 (230 ° C / 2.16kg) and a relative solution viscosity of 2.7 (reference polyamide II), polypropylene with a melt index of 24 (230 ° C / 2.16kg), Octadecyla-modified montmorillonite (eg Nanofil 848) in a weight ratio of 80/15/5 was compounded. The PA 6 / PP nanocomposite blend showed improved mechanical and thermal properties, a modulus of elasticity increase of 43% and HDT increase of 73%.

Properties of the blend: modulus of elasticity: 3860MPa HDT (1,8MPa): 95 ° C.

Properties of the ref.polyamide II: modulus of elasticity: 2700MPa HDT (1,8MPa): 55 ° C.

Comparative Example 6

Polyamide 6 with a melt index of 6, 6 (230 ° C / 2, 16kg) and a relative solution viscosity of 3.2 (reference polyamide III) and octadecylamine-modified montmorillonite (eg Nanofil 848) in a weight ratio of 95/5 were compounded , 0.2% Irganox was added to the mixture B1171 (a blend of heat stabilizer and process stabilizer) added.

Comparative Example 7

Polyamide 6 with a melt index of 6, 6 (230 ° C / 2, 16kg) and a relative solution viscosity of 3.2 (reference

Polyamide III) was added with 0.2% Irganox B1171

(A blend of heat stabilizer and process stabilizer) processed.

Table 4: Properties of PA / PP nanocomposite blends

Examples 8 to 16 - two-step process

The PA / PP nanocomposite blends were produced using a twin-screw extruder (ZSK 25/40, Coperion Werner & Pfleiderer) with an L / D ratio of at least 40. The polymers and the organically intercalated layered silicates were metered in in the first zone using polymer or powder scales. The compounding was carried out at temperatures in the zones between 220 and 260 ° C and a speed of 250 or 400 min ^-1 . First, Masterbatches PA 6 / Clay were made with or without ethylene acrylic acid or ethylene methacrylic acid ionomer. The corresponding masterbatches were then compounded with PP and PA 6. The total throughput in masterbatch production and compounding was 6 kg / h.

The compounded nanocomposite blends were processed into test specimens using injection molding (Arburg Alllrounder 320M 850-210).

Using WAXS analyzes (WAXS = wide-angle X-ray structure analysis), the distances between the silicate platelets in the master batches were determined.

The mechanical properties of the nanocomposite blends (freshly injected and conditioned) were tested in a tensile test according to DIN EN ISO 527 and a notched impact test according to DIN EN ISO 179 / leA.

The dynamic-mechanical behavior of the nanocomposite blends was tested on the torsion tester RDA II (Rheometrics) with constant elongation of 0.1% and a fre- frequency of 1 Hz examined. The composition of the nanocomposite blends is shown in the following examples and the properties are shown in Tables 4 and 5, the storage module depending on the temperature in Figure 7.

The samples in Examples 8 to 16 were conditioned in accordance with EN ISO 1110 at 70 ° C. and 62% relative humidity to constant weight. Test bars from samples 10 to 15 were stored in a circulating air oven at 150 ° C and the properties were then tested in a tensile test.

The solution viscosity of polyamide 6 was measured in a 1% solution in sulfuric acid (96%) at 25 ° C.

Example 8

Polyamide 6 with a melt index of 6, 6 (230 ° C / 2, 16kg) and a relative solution viscosity of 3.2 (reference polyamide III), polypropylene with a melt index of 6 (230 ° C / 2, 16kg) and octadecylamine modified montmorillonite (eg Nanofil 848) was used.

First a masterbatch with the composition 80/20 PA 6 / Clay was produced. WAXS investigations showed that the layer spacing between the silicate wafers widened by more than 4.5 nm. The masterbatch was then compounded with PA 6 and PP so that the final concentration of the components in the PA 6 / PP / Clay mixture was 80/15/5 by weight. Example 9

The same materials and procedure as in Example 10 were used. The final concentration of the components in the mixture was PA β / PP / Clay - 70/25/5 in the weight ratio.

Example 10

Polyamide 6 with a melt index of 6, 6 (230 ° C / 2, 16kg) and a relative solution viscosity of 3.2 (reference polyamide III), polypropylene with a melt index of 6 (230 ° C / 2, 16kg), a low molecular weight Ethylene acrylic acid copolymer completely neutralized with Zn (eg Aclyn 295) referred to here as ionic Ac and octadecylamine-modified montmorillonite (eg Nanofil 848) was used.

First, a masterbatch with the composition 75/5/20 PA 6 / ionomer Ac / Clay was produced. WAXS investigations showed that the layer spacing between the silicate wafers had widened by more than 4.26 nm. The masterbatch was then compounded with PA 6 and PP so that the final concentration of the components in the mixture PA 6 / PP / Ionomer Ac / Clay was 79/15/1/5 in the weight ratio.

Example 11

The same materials and procedure as in Example 12 were used. The final concentration of the components in the mixture was PA 6 / PP / Ionomer Ac / Clay - 69/25/1/5 in the weight ratio. Example 12

Polyamide 6 with a melt index of 6, 6 (230 ° C / 2, 16kg) and a relative solution viscosity of 3.2 (reference polyamide III), polypropylene with a melt index of 6 (230 ° C / 2, 16kg), a low molecular weight ethylene acrylic acid copolymer partially neutralized with Zn (eg Aclyn 291) referred to here as ionic Acl and octadecylamine-modified montmorillonite (eg Nanofil 848) was used.

First, a masterbatch with the composition 72.5 / 7.5 / 20 PA 6 / ionomer Acl / Clay was produced. WAXS investigations showed that the layer spacing between the silicate wafers widened by more than 4.26 nm. The masterbatch was then compounded with PA 6 and PP so that the final concentration of the components in the PA 6 / PP / ionomer Acl / Clay mixture was 78.2 / 15 / 1.8 / 5 in weight ratio.

Example 13

The same materials and procedure as in Example 14 were used. The final concentration of the components in the mixture was PA 6 / PP / Ionomer Acl / Clay - 69.5 / 25 / 1.5 / 4 in the weight ratio.

Example 14

Polyamide 6 with a melt index of 6, 6 (230 ° C / 2, 16kg) and a relative solution viscosity of 3.2 (reference polyamide III), polypropylene with a melt index of 6 (230 ° C / 2, 16kg), a high molecular weight ethylene-methacrylic acid copolymer (eg Surlyn), partially neutralized with Zn, referred to here as ionomer Sr and octadecylamine modified montmorillonite (eg Nanofil 848) was used.

First, a masterbatch with the composition 72.5 / 7.5 / 20 PA 6 / ionomer Sr / Clay was produced. WAXS investigations showed that the layer spacing between the silicate wafers widened by more than 4.3 nm. The masterbatch was then compounded with PA 6 and PP so that the final concentration of the components in the PA 6 / PP / ionomer Sr / Clay mixture was 78.2 / 15 / 1.8 / 5 in weight ratio.

Example 15

The same materials and procedure as in Example 16 were used. The final concentration of the components in the mixture was PA 6 / PP / ionomer Sr / Clay - 69.5 / 25 / 1.5 / 4 in weight ratio.

Example 16 The same materials and procedure as in Example 16 were used. The final concentration of the components in the mixture was PA 6 / PP / ionomer Sr / Clay - 55.9 / 40 / 1.1 / 3 in weight ratio.

Table 5: Properties of PA / PP nanocomposite blends

Figures 1 to 7 concern

Figure 1: Water absorption of the nanocomposite blends at 23 ° C and 95% relative humidity depending on the storage time

Figure 2: Water absorption of the nanocomposite blends at 23 ° C in water depending on the storage time

Figure 3: E-moduli of the nanocomposite blends when freshly sprayed and conditioned (23 ° C / 95% relative humidity - after 280 hours; 23 ° / in water - after 1800 hours and after 4000 hours)

Figure 4: TEM image of PA 6 / PP nanocomposite blends - ultra-thin sections: a) contrasted, b) not contrasted

Figure 5: SEM images of cryogenic fracture areas of the test rods of PA 6 / PP nanocomposite blends: a) without additional compatibilization, b) with 1.8% by weight ethylene-ionomer copolymer

Figure 6: Storage module of the PA / PP nanocomposite blends according to the invention as a function of the temperature

Figure 7: Memory module of the PA / PP nanocomposite blends according to the invention depending on the temperature

Claims

claims

1. Nanocomposite blends, the a) polyamide (PA) from 55 to 95% by weight, b) polypropylene (PP) from 4 to 40% by weight, c) nanodisperse layered silicates from 1 to 9% by weight d) carboxylated polyolefins , in particular copolymers of ethylene with unsaturated carboxylic acids, up to 10% by weight, which can contain additives of conventional stabilizers and fillers over a total of 100% by weight.

2. Polymer-nanocomposite blends according to claim 1, characterized in that component a). is a polyamide 6 with a solution viscosity of 2.2 to 4.0, preferably 2.4 to 3.5.

3. Polymer-nanocomposite blends according to claim 1 or 2, characterized in that component b) is a polypropylene with a melt index of 1 to 110, preferably 5 to 30 ccm / 10 min (230 ° C / 2.16 kg) is.

4. Polymer-nanocomposite blends according to one or more of claims 1 to 3, characterized in that the nanodisperse layered silicate (component c) is a natural sodium montmorillonite modified with onium ions, hectorite, bentonite or synthetic mica with a cation exchange capacity - act from 60 to 150 meq / lOOg.

5. Polymer-nanocomposite blends according to one or more of claims 1 to 4, characterized in that component d) is contained in the nanocomposite blends from 0.1 to 1.9% by weight and preferably an ethylene-acrylic acid Copolymer or an ethylene-methacrylic acid copolymer which is partially or completely neutralized with metal ions.

6. Process for the production of polymer-nanocomposite blends, characterized in that the components

Polyamide (PA) from 55 to 95% by weight, polypropylene (PP) from 4 to 40% by weight, nanodisperse layer silicates from 1 to 9% by weight, carboxylated polyolefins, in particular copolymers of ethylene with unsaturated carboxylic acids, up to 10% by weight contain, which can contain additives of conventional stabilizers and fillers over the composition of a total of 100 wt.%, were compounded at temperatures above the melting temperatures of the polymers involved in an extruder or kneader.

7. The method according to claim 6, characterized in that the components are compounded in one step.

A method according to claim 6, characterized in that components c) and d) in parts of the compo- nente a) are first incorporated in the form of a masterbatch and the masterbatch in the next step is compounded with component b) and the rest of component a) and processed further.

9. The method according to claim 6, characterized in that components d) and component b) are first compounded above the melting temperatures of the polymers involved in an extruder or kneader to give a modified polypropylene and component c) and part of component a) in Form of a masterbatch and in the next step the masterbatch is compounded and processed with the modified polypropylene and the rest of component a).

10. The method according to claim 6, characterized in that components d) and component b) are first compounded above the melting temperatures of the polymers involved in an extruder or kneader to form a modified polypropylene and the modified polypropylene in the next step with the component a) and component d) is compounded and processed.

11. Use of the nanocomposite blends according to one of claims 1 to 5, produced according to one of claims 6 to 10 as extrudates, injection molded parts or fibers.