WO2009071549A1

WO2009071549A1 - Thermoplastic compositions for footwear with no marking characteristics

Info

Publication number: WO2009071549A1
Application number: PCT/EP2008/066643
Authority: WO
Inventors: Antonio Batistini; Gianni Perozzi
Original assignee: Dow Global Technologies LLC
Current assignee: Dow Global Technologies LLC
Priority date: 2007-12-06
Filing date: 2008-12-02
Publication date: 2009-06-11
Anticipated expiration: 2010-06-06
Also published as: BRPI0819054A2; EP2220159A1; TW200936681A

Abstract

A dark pigmented thermoplastic elastomer composition for production of articles, in particular, footwear components, and which comprises the following main components: (a) one or more styrene butadiene styrene (SBS) block copolymers, and/or at least one of (b) and (c) wherein: (b) is one or more polyolefin elastomers and (c) is one or more thermoplastic polyurethanes (TPU); and (d) a black pigment composition which is carbon black free; and optionally contains other ancillary components such as extender oils, hardness regulators, fillers, plasticizers, pigments, blowing agents, and the like.

Description

THERMOPLASTIC COMPOSITIONS FOR FOOTWEAR WITH NO MARKING CHARACTERISTICS

Field of the invention The invention relates to a dark pigmented thermoplastic elastomer composition for, in particular, use in footwear components. Preferably such components have low marking, and more preferably no marking, characteristics from wear friction . Background of the invention

Thermoplastic elastomer (TPE) compositions are based on materials which behave like elastomeric rubbers at room temperature, but when heated can be processed like plastics. These materials have a look and touch comparable to vulcanized rubber, although their technology, workability, and recyclability are typical of thermoplastic products. The TPE most frequently used in the production of shoe soles are styrenic block copolymers such as poly styrene-butadiene- styrene (SBS) copolymers. TPEs compositions based on SBS and/or thermoplastic polyurethane (TPU) have been used in the footwear industry for several years; formulations comprising SBS, ethene-vinyl acetate (EVA) , oils, polyolefins, TPU, fillers, anti-oxidants, pigments and other ingredients are well known in the industry. Improvements of such formulations have been described in the prior art, e.g. the "dull look" obtained via addition of metallocene polyolefins (WO 01/25331);

Thermoplastic materials based on polyurethane components for forming light foamed products, in particular, for forming soles for footwear are described in WO 2006/090221.

Dark colored TPEs are known to exhibit undesired marking effects of the contact surface. In particular such behaviour is undesired when said compounds are used to produce shoe soles. The need for obtaining a TPE compound which is suitable for the production of shoe soles having no marking effect on the contact surface is still unmet. Summary of the invention

The invention relates to a dark pigmented thermoplastic elastomer composition suitable, for production of articles, in particular, footwear components. Such composition comprises:

(a) one or more styrene butadiene styrene block copolymers (SBS), and/or at least one of (b) and (c) wherein: (b) is one or more polyolefin elastomers which are olefin copolymers of ethene (the term ethylene is more commonly used) and an alpha olefin comonomer, or copolymers propylene and ethylene or an alpha olefin comonomer and (c) is one or more thermoplastic polyurethanes (TPU) ; and

(d) a black pigment composition which is carbon black free; (e) optionally, polydimethylsiloxane (PDMS);

(f) optionally, one or more ingredients selected from extender oils, fillers, hardness regulators, flow improvers, flex crack resistance improvers, stabilizers, UV stabilizers, pigments, blowing agents, and anti- blocking agents.

The TPE compositions described above can be used in particular, to produce dark colored footwear components such as shoe soles and heels.

Moreover, the TPE compositions according to this invention may find other industrial applications in the fields where TPE compositions are used and low or no marking effects under friction are desired.

Detailed description of the invention

The TPE compositions according to this invention allow production of manufactured articles, in particular shoe soles which do not exhibit the marking of the contact surface from wear friction typically associated with the current dark pigmented thermoplastic elastomer compounds.

In this description and claims the expression "dark pigmented thermoplastic composition" or "dark pigmented thermoplastic elastomer (TPE) composition" means a thermoplastic elastomer composition which contains one or more coloring pigment (s) wherein at least 40 per cent by weight of the total coloring pigment (s) in the thermoplastic elastomer composition is a black color pigment" .

Each component (a) , (b) and (c) of the TPE compositions if this invention can be present in said compositions, alternatively, alone or in combination with at least one of the other two in the proportion by weight that are indicated below. The component (d) constitutes a specific and distinguishing feature of this invention and is always present in the TPE compositions of this invention. The components (e) and (f) are optionally present in the TPE compositions. According to a preferred embodiment of the invention, one, or more ingredients listed under (f) is/are usually comprised by these TPE compositions.

The single components of the TPE compositions are described below in more detail: Component (a) This component consists of one or more styrene butadiene styrene (SBS) block copolymers having two or more distinct polymer blocks, at least one of which is glassy (i.e., below glass transition point, therefore brittle and stiff) at service temperature but fluid at higher temperatures, and at least one of which is elastomeric (i.e., above glass transition point, therefore flexible or elastic) at service temperature .

In the styrene butadiene styrene block copolymers utilized according to this invention, the styrene (S) and butadiene (B) monomers can be replaced by, respectively, other vinylaromatic and 1 , 3-conjugated diene monomers. Accordingly, in this description and claims, when not otherwise specified, the terms "butadiene-styrene-butadiene block copolymers" or "SBS block copolymers" include also those block copolymers where the styrene and butadiene monomers are replaced by the other vinylaromatic and 1, 3-conjugated diene that are hereafter defined in more detail.

The SBS block copolymers can be in the form of linear diblock, triblocks and multiblock SBS copolymers or in the form of radial SBS block copolymers.

A mixture of linear SBS block copolymer and of radial SBS block copolymer can also be used, according to this invention. The methods for producing these SBS block copolymers for use according to this invention are well known in the art. See for instance US 3,251,905, US 3,231,635, US 3,598,887 and US 4,219,627.

The glassy block (s) of the SBS block copolymers is/are made of a vinylaromatic monomer, such as styrene. Although styrene is the preferred monomer, other vinylaromatic monomers can be employed such as α-methylstyrene, other styrene derivatives where the benzene ring is substituted by one to three (Ci- C₄)alkyls, preferably methyl or ethyl group (s), or vinylnaphthalene optionally substituted by one or two methyl or ethyl groups. Each styrene glassy polymer block contains a total styrene monomer amount of at least 80 mole percent, the remaining portion, if any, consisting of other vinylaromatic monomer (s), e.g. CC-methyl styrene.

The elastomeric block (s) of the SBS block copolymers used as component (a) of the TPE compositions according to this invention are made of polymerized conjugated 1,3-diene, such as butadiene. Although 1, 3-butadiene is the preferred monomer, other conjugated diene of 5-6 carbon atoms can be employed, such as isoprene, 1, 3-pentadiene, 2, 3-dimethyl-l, 3-butadiene, and 2 , 4-hexadiene . These conjugated dienes may be polymerized in either 1,2 or 1,4-fashion to a vinyl content in the range of 5 to 80% (mole%) .

Each elastomeric block of the SBS block copolymer contains a total conjugated diene monomer, such as butadiene or isoprene, which is more than 50%, preferably at least 70% (mole%) , the remaining portion, if any, consisting of other co- polymerizable monomers such as vinylaromatic monomers. The SBS block copolymers employed as component (a) according to this invention may also be partially or fully hydrogenated. Preferred hydrogenated SBS block copolymers for use as component (a) are those wherein only the elastomeric block is selectively hydrogenated (usually more than 80%, preferably more than 99% (mole%) on total unsaturation) . In one embodiment, the ratio between the 1, 3-conjugated diene preferably butadiene, and the vinylaromatic monomer, preferably styrene, in the SBS block copolymer is from 90 to 10, preferably from 80 to 20, more preferably is 70 to 30 (molar%) . The total weight average molecular weight of the SBS block copolymer preferably ranges from 100.000 to 500.000, more preferably from 150.000 to 400.000 (g/mole) .

The SBS block copolymers can be extended with hydrocarbon extender oils such as paraffin and or naphthenic oils which are hereinafter described in more detail, in an amount that ranges from 0 to 40 part by weight of the total extended SBS block copolymer. The extender oils may be already included in the SBS block copolymers which are commercially available. The amount of component (a) in the TPE composition in general ranges from 0 to 80 per cent by weight, preferably from 0 to 70, more preferably from 0 and 60 by weight, based on total weight of the composition.

SBS block copolymers which are suitable for the TPE compositions of this invention include EUROPRENE SOl T172 SBS block copolymer (Polimeri Europa of San Donato Milanese, Milan, Italy), KRATON (Texas Pacific, Fort Worth, Texas, USA), STEREON (Fireston, Akorn, Ohio, USA), FINAPRENE (Total Petrochemicals Elastomers, Brussels, Belgium) , TUFPRENE (Asahi Kasei Corp., Tokyo, Japan) and others. The SBS block copolymer material of component (a) can be partially substituted up to 40% by weight, based on total weight of the composition, by a polybutadiene polymer (see, for instance "Component J" in TABLE 1), a polyolefin elastomer such as ethylene/propylene copolymers, e.g. EPDM copolymers, or by styrene-butadiene (SBR) copolymers. Component (b)

This component consists of one or more polyolefin elastomers. The olefin copolymer of component (b) for use in the TPE composition of the present invention is an olefin copolymer that has a density from 0.86 to 0.92 g/cm³ and is obtained through copolymerization of ethylene with an α-olefin, or the copolymerization of propylene with ethylene or an α-olefin having 4 to 12 carbon atoms. In a preferred embodiment, the olefin copolymer is obtained through copolymerization of ethylene with an α-olefin, including, but not limited to, propylene and an α-olefin having 4 to 12 carbon atoms, and more preferably the copolymerization of ethylene with 1-butene, 1- hexene or 1-octene.

Examples of the α-olefin having 4 to 12 carbon atoms used to form the ethylene or propylene and α-olefin copolymer of component (b) include 1-butene, 2-methyl-l-butene, 3-methyl-l- butene, 1-pentene, 4-methyl-l-pentene, 1-hexene, 1-octene, 1- decene and 1-dodecene. These α-olefins may be used individually or in combinations of two or more to provide the structural units of the olefin copolymer (b) .

The olefin copolymer of component (b) may be any of the known materials. For example, those that have a density of 0.86 to 0.92 g/cm³, are selected from the products including ENGAGE (product name) available from The Dow Chemical Company, EXACT series (product name) manufactured by ExxonMobil Chemical Co., Ltd., TAFMER series (product name) manufactured by Mitsui Petrochemical Industries Ltd., and N-series of ESPREN SPO (product name) manufactured by Sumitomo Chemical Industry Co., Ltd.

Examples of metallocene based polyolefin elastomers (elastomers prepared in the presence of a metallocene catalyst, including, for example, bis-metallocene catalysts and contained geometry catalysts) for use in the present invention are described, for example, in US Patents 4,871,705; 5322728 and 5272236. In particular, metallocene polyolefins produced by copolymerizing ethylene with from 8% to 40% (mole%) of an alpha-olefin of 3 to 20 carbon atoms, preferably from 4 to 12 carbon atoms, more preferably from 6 to 10 carbon atoms, with a good distribution of ethene and comonomers are suitably employed as component (b) . Furthermore, it is preferred that such polyolefins have a low crystallinity degree .

Preferably, these metallocene polyolefins have a Melt Flow Index ("MFI" at 190°C/5kg, determined in accordance with ISO 1133) ranging from 0.5 to 40 g/min, preferably from 1.0 to 30 g/10 min, and their density is in the range from 0.86 to 0.89 kg/1, and preferably from 0.86 to 0.885 kg/1.

Commercially available metallocene polyolefins which can be utilized as component (b) of the TPE compositions of this invention are, for instance, the ethene (or ethylene) -octene copolymers marketed under the trademarks AFFINITY, and ENGAGE (by The Dow Chemical Company) , EXACT (by ExxonMobil Chemical Co.) and TAMFER (from Mitsui Petrochemical Industries Ltd.) . The amount of component (b) in the TPE composition of this invention may range from 0 to 99 per cent by weight, preferably from 0 and 80, more preferably from 0 and 60, based on total weight of the composition. Component (c) This component consists of thermoplastic polyurethanes (TPU) , i.e., substances obtained by reaction of a diisocyanate composition with at least one difunctional compound capable of reacting with an isocyanate group, preferably, at least one difunctional polyhydroxy compound, and optionally a chain extender. The term difunctional means that the average functionality of the isocyanate composition or the polyhydroxy compound is about 2. The diisocyanate reactant may be aromatic or aliphatic. Aromatic diisocyanates include, for example, 4,4'- and 2, 2 ' -diphenyl-methanediisocyanate (MDI) and the corresponding isomeric mixtures. The diisocyanate component may also be an MDI variant. MDI variants are well known in the art, and particularly include liquid products obtained by introducing carbodiimide groups into said diisocyanate composition. Examples of aliphatic and cycloaliphatic isocyanate compounds include 1, 6-hexamethylene-diisocyanate (HDI); isophorone diisocyanate (IPDI); 4,4'-, 2,2'- and 2,4'- dicyclohexylmethanediisocyanate (H12MDI), the isomeric mixtures thereof; 1, 3-tetramethylene xylene diisocyanate; norbane diisocyanate; and 1,3- and 1,4- bis (isocyanatomethyl) cyclohexane can also be used with the present invention. Mixtures of the aromatic, aliphatic and cycloaliphatic isocyanates may also be used.

Preferred are isocyanate compositions comprising aromatic diisocyanate and more preferably MDI. In one embodiment, the difunctional compound, preferably a difunctional polyhydroxy compound, has a molecular weight of between 500 and 20000, and may be selected from derivatives of polyesteramides, polythioethers, polycarbonates, polyacetals, polyolefins, polysiloxanes and especially, polyesters, polyethers, polycaprolactone or mixtures thereof. Polyesters include hydroxy-polyesters reaction products of dihydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, 1, 4-butanediol, neopentyl glycol, 2- methylpropanediol, 3-methylpentane-l, 5-diol, 1, 6-hexanediol, or cyclohexane dimethanol or mixtures thereof, and dicarboxilic acids or their esters, such as adipic, glutaric, succinic, sebacic, and terephthalic acid, phthalic anhydride, tetrachlorophthalic anhydride or mixture thereof. Polyethers include products obtained by the polymerization of a cyclic oxide, e.g. ethylene, propylene, butylene oxide or tetrahydrofuran in the presence, where necessary, of difunctional initiators. Suitable initiator compounds include water, ethylene glycol, propylene glycol, di-ethylene glycol, tri-ethylene glycol, di-propylene glycol, 1, 3-propanediol, 1, 4-butanediol, neopentyl glycol, 1, 5-pentanediol, 1,6- hexanediol and the like. Mixtures of initiators and/or cyclic oxides may be used.

Polyolefin diols include hydroxyl-terminated butadiene homo- and copolymers. Suitable chain extender include aliphatic diols, such as ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1,5- pentanediol, 1, 6-hexanediol, 1, 2-propanediol, 2- methylpropanediol, 1, 3-butanediol, 2, 3-butanediol, 1,3- pentanediol 1, 2-hexanediol, 3-methylpentane-l, 5-diol, neopentyl glycol, diethylene glycol, di-propylene glycol and tri-propylene glycol, and aminoalcohols such as ethanolamine, N-methyldiethanolamine and the like; 1, 4-butanediol is preferred.

The TPU employed as component (c) of the TPE compositions of this invention may optionally contain additives, stabilizers, surface active agents and foam stabilizers, plasticizers, and the like.

Additives that can be mixed with the TPU are, for instance, poly-vinyl chloride or ethylvinylacetate, paraffin or naphthenic oil, fillers of mineral origin, and the like. Stabilizers which may be added to the TPU include anti-static and anti-oxidant and anti-UV.

Surface active agents and foam stabilizers which may be added to the TPU include for example, siloxane-oxyalkylene copolymers . Plasticizers of the TPU component include, for instance, alkyl phthalates and alkyl-benzoates .

Suitable TPUs are commercially available, and include, among others, those sold under the name EPAMOULD (Epaflex Polyurethane S.r.l., Milan, Italy), LARIPUR (Coim S. p. A., Settimo Milanese (Milan), Italy), APILON (Api Plastic S. p. A., Mussolente (Vicenza) , Italy), AVALON (Huntsman Poyurethanes, Salt Lake City, Utah, USA) and ELASTOLLAN (Elastogran GmbH, Lamfoerde, Germany), PELLETHANE (The Dow Chemical Co., Midland, Michigan USA) . The amount of component (c) in the TPE composition in general may range from 0 to 80, preferably from 0 to 60 more preferably 0 to 40 per cent by weight, based on total weight of the composition. Component (d) This component constitutes an essential feature of the TPE composition of this invention since it gives the dark color to the footwear produced with the TPE composition without involving any marking effect. As used herein, a black pigment is a pigment, which when blended into a thermoplastic polymer or polymer composition, at a level of 0.1 to 3 per cent by weight %, based on the total weight of the final composition, leads to a reflectance (of this blend) of less than 15 % over the wavelength from 400 to 700 nm, as measured by a spectrophotometer equipped with an integrating sphere and using a setting such that the specular component of the light reflectance is included Preferable the reflectance is less than 12 %. More preferable the reflectance is less than 9%. In one embodiment the reflectance of the pigmented polymer over this wavelength pattern is less than 7 %. ASTM E 1349 Standard Test Method for Reflectance Factor and Color by Spectrophometry, Using Bidirectional (45°:0° or 0°:45°) Geometry, with a ReflectanScan Reflectance Spectrophotometer, from Cecil Instruments Ltd., can be used to measure reflectance. The term "black pigment" composition, as used herein, refers to a composition comprising a black pigment, as discussed above .

The TPE composition of this invention may contain other pigments, which are not black pigments, besides the black pigment of component (d) hereabove defined. For use in the present invention, the black pigment component (d) generally comprises at least 40 wt% of the total pigment used in the dark pigmented thermoplastic composition. If desired, the black pigment can comprise greater than 60 wt%, or even greater than 70 wt% of the total pigment used in the dark pigmented thermoplastic composition. If desired, the black pigment may comprise 100 wt% of the pigment added to the dark thermoplastic composition. This component is characterized in that it is carbon black free.

An example of black pigments or combination of pigments for use in the present invention include, for example, those commercialized by Clariant Masterbatches S. p. A., Milan, Italy under the trademarks RENOL PV90050120 - BN/GUM and RENOL PC GUM NERO CBF.

The amount of component (d) in the TPE composition may range from 0.1 to 3 per cent by weight, based on total weight of the composition . Component (e) This component is a polydiorganosiloxane, having a viscosity of at least one million centistokes at 25⁰C. Such an additive can be added to further increase wear resistance of developed formulations, as well as act as internal lubricating and demoulding agent . The amount of component (e) in the TPE composition may range from 0 to 4% by weight, based on total weight of the composition . Component (f) This optional component of the TPE compositions may comprise extender oils which may be added to the whole composition blend in addition to the amount which may be originally included into the SBS block copolymer (component (a) ) , as described above. These extender oils are products deriving from petroleum refining having less than 30 per cent by weight of aromatic hydrocarbons .

The amount of extender oil which may be added to the whole composition blend besides the amount that may be included into the component (a) , when present in the composition blend, ranges from 0 to 40 by weight, based on total weight of the composition .

Commercially available extender oils include, for example, CELTIS 902 from ENI S. p. A., Stagno (Livorno) Italy . Other ingredients which may be optionally present in the TPE composition of this invention include, for instance, fillers of mineral origin such as clay, silica, talc, calcium carbonate, alumina and the like, hardness regulators such as polystyrene crystals, other (not black) pigments, and chemical or physical blowing agents. Blowing agents are usually added to the other components of the TPE composition when it is desired to reduce the density of the TPE up to 0.5 kg/1. Any known blowing agent used for the preparation of foamed thermoplastic products may be used in the present invention. The blowing agents are usually added according to a known method such as the one described in WO 00/44821, wherein the blowing agent is encapsulated and contained in special microspheres added to the granulated TPE blend mixture, or according to the method disclosed in WO 2006/090221. Any thermally expandable microspheres can be used in the present invention. However, microspheres containing hydrocarbons, in particular aliphatic or cycloaliphatic hydrocarbons, are preferred.

The micro-cells or microspheres containing the blowing agent which are incorporated into the TPE blend mixture according to the above mentioned methods consist of a copolymer of the acrylic/methacrylonitrile or acrylonitrile/acrylic or ester/olefin group encapsulating the blowing agent. Examples of suitable physical blowing agents include volatile liquids such as chlorofluorocarbons, partially halogenated hydrocarbons or non-halogenated hydrocarbons like propane, n- butane, isobutane, n-pentane, isopentane and/or neopentane. Microspheres containing aliphatic or cycloaliphatic hydrocarbons are commercially available, for instance, under the trademark EXPANCELL, (AKZO Nobel Industries, Amsterdam, Holland) or MICROPEARL (Matsumoto Yushi Seiyaku, Osaka Japan) . Both endothermic and exothermic chemical blowing agents can be used. Examples of suitable chemical blowing agents include gaseous compounds such as nitrogen or carbon dioxide, gas (e.g. CO₂) forming compounds such as azodicarbonamides, carbonates, bicarbonates, citrates, nitrates, borohydrides, carbides such as alkaline earth and alkali metal carbonates and bicarbonates e.g. sodium bicarbonate and sodium carbonate, ammonium carbonate, diaminodiphenylsulphone, hydrazides, malonic acid, citric acid, sodium monocitrate, ureas, azodicarbonic methyl ester, diazabicylooctane and acid/carbonate mixtures.

Preferred endothermic blowing agents comprise bicarbonates or citrates . Azodicarbonamide type blowing agents are preferred as exothermic blowing agents.

The amount of the optional ingredients, other than the extender oils, which are collectively designated hereinabove as component (f ) , as a whole, may range from 0 to 4 per cent by weight . In particular, the amount of blowing agent (s), when employed, may range from 1 to 3 per cent by weight.

According to an embodiment of this invention, the TPE compositions, suitable for the production of shoe soles with no marking effect, have no or low polystyrene and mineral filler content, and have no or low level of plasticizer.

It is understood that the total per cent amount of the various components (a) to (f) of the TPE of this invention, each of which is falling within the intervals specified above, must sum up to 100 per cent and that the total amount of component (s) (a) and/or at least one of one of (b) and (c) in the TPE composition must be at least 55 per cent, preferably at least 70 percent, more preferably at least 80 percent by weight, based on total weight of the composition. Compounding and Injection moulding The formulations for the TPE compositions of this invention are prepared according to compounding procedures known to the skilled in the art. In practice, all components are mixed by using a tumble mixer at variable speed and then fed to a co- rotating twin screw extruder at 140-220⁰C. The extruded strands are water cooled and granulated. The granules are molded using a injection moulding machine with the injection unit set at 12O⁰C to 16O⁰C to obtain plates and soles prototypes. Testing Plates and soles prototypes are tested for abrasion resistance, tensile strength, elongation, tear and strength. The tests are carried out on plates according to the DIN methods indicated in TABLE 2. The marking effect is evaluated by visual inspection, after manually fractioning the molded plates sample on a surface, e.g. the tiles, hardwood, vinyl flooring. EXAMPLES

The following components are used in the examples reported in TABLE 1. Component A: EUROPRENE Sol T 172 SBS block copolymer, 70% (mole%) butadiene, 30% styrene, extended with paraffinic oil (50 pbw for 100 of polymer); from Polimeri Europa, San Donato Milanese, Milan (Italy) Component B: ENGAGE 8200, ethene/octene copolymer, from Dow Chemical Company, Midland, Michigan - (USA)

Component C: EPAMOULD 8OA, polyester based thermoplastic polyurethane; from Epaflex Polyurethane SrI - Milan (Italy) Component D: RENOL PV 90050120-BN/GUM, black master batch from carbon black free pigment composition into PE-EVA from Clariant Masterbatches SpA - Milan (Italy) . Component E: Polydimethylsiloxane (MP50 from Dow Corning Co) having a viscosity of 20 million centistokes at 25⁰C

Component F: CELTIS 902, paraffinic oil; from ENI SpA - Stagno

(Livorno-Italy)

Component G: SARMAPRENE Nero tech; from Clariant Masterbatches

SpA - Milan (Italy)

Component H: Mineral filler calcium carbonate, from Omya SpA -

Milan (Italy)

Component I : Polystyrene crystal, melt flow index 25 at 19O⁰C,

5kg; from Ecoplastic SrI - Milan (Italy)

Component J: JSR RB 840/830, syndiotactic polybutadiene polymer; from JSR Corporation - Tokio (Japan)

All compounds are mixed and compounded as described above.

The pellets or granules obtained therefrom are injection moulded into plates which are submitted to testing as described above.

TABLE 1

Examples 1, 2, 5 and 7 are comparative examples which are carried out according to the teachings of the state of the art.

Examples 3, 4, 6 and 8 are representative of the invention without establishing any limit thereof. The results of tests carried out on plates are reported in TABLE 2 below.

TABLE 2

The above test results show that the TPE compositions of this invention allow production of dark pigmented articles, in particular, footwear such as shoe soles and heels that maintain the functional characteristic required for their use (i.e., abrasion resistance, tear and tensile strength, etc.), and do not show any undesired marking effect.

Moreover, by comparing examples 1 and 2 with examples 3 and 4, it is evident that the marking effect is not just a matter of abrasion resistance or the other mechanical properties of the materials.

Claims

1. A dark pigmented thermoplastic elastomer (TPE) composition for production of articles, in particular, footwear, and comprising the following components: (a) one or more styrene butadiene styrene (SBS) block copolymers, and/or at least one of (b) and (c) wherein: (b) is one or more polyolefin elastomers, and (c) is one or more thermoplastic polyurethanes (TPU) ; and

(f) optionally, one or more ingredients selected from extender oils, fillers, hardness regulators, flow improvers, flex crack resistance improvers, stabilizers, UV stabilizers, pigments, blowing agents, and anti-blocking agents.

2. A dark pigmented thermoplastic elastomer (TPE) composition of claim 1, wherein:

(i) the amount of component (a) is ranging from 0 to 80 per cent, preferably from 0 to 70 per cent, more preferably from 0 to 60 per cent by weight, based on total weight of the composition;

(ii) the amount of component (b) is ranging from 0 to 99 per cent, preferably from 0 to 80 per cent, more preferably from 0 to 60, per cent by weight, based on total weight of the composition; (iϋ) the amount of component (c) is ranging from 0 to 80 per cent, preferably from 0 to 60, per cent more preferably from 0 to 40 per cent by weight, based on total weight of the composition;

(iv) the amount of component (d) is ranging from 0.1 to 3 per cent by weight, based on total weight of the composition; and wherein the total amount of component (s) (a) and/or at least one of (b) and (c) in the TPE composition is at least 55 per cent, preferably at least 70 per cent, more preferably at least 80 per cent by weight, the remaining portion consisting of component (d) and, if any, component (e) and/or of one or more ingredients of component (f ) .

3. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 and 2, which contains component (a) where the styrene butadiene styrene (SBS) block copolymer of said component (a) consists of two or more distinct polymer blocks, at least one of which is glassy at service temperature, but fluid at higher temperature, and is made of styrene or other vinyl aromatic monomers, preferably styrene or CC- methylstyrene, and at least one of which is elastomeric at service temperature, and is made of polymerized conjugated diene, preferably 1, 3-butadiene or isoprene.

4. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 3, which contains component (b, ) where the polyolefin elastomers of said component (b) are polyolefins produced by copolymerizing ethylene with from 8 to 40 mole percent of an alpha-olefin of 3 to 20 carbon atoms, preferably from 4 to 12 carbon atoms, more preferably from 6 to 10 carbon atoms, the polymerization catalyst preferably being a metallocene catalyst

5. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 4, which contains component (c, ) where the thermoplastic polyurethane (TPU) of said component (c) is made by reacting a diisocyanate composition, preferably a isocyanate composition comprising an aromatic diisocyanate, more preferably MDI, with at least one difunctional polyhydroxy compound and optionally a chain extender.

6. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 5, where the black pigment composition of said component (d) is a carbon black free composition which is obtained by different color pigments and, when blended into a polymer at a level of 0.1 to 3% by weight, leads to a reflectance of said blend over the wavelength from 400 to 700 nm of less than 15%, preferably less than 12%, more preferably less than 9%, most preferably less than 7%.

7. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 6, which contains the poly- dimethylsiloxane component (e) in an amount lower than 4% by weight, based on total weight of the composition.

8. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 7, which comprises an ingredients of component (f) which is an extender oil, in an amount lower than 40% by weight, based on total weight of the composition.

9. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 8, which comprises an ingredient of component (f) which is a blowing agent in an amount from 1 to 3 per cent by weight, based on total weight of the composition .

10. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 9, which contains a SBS block copolymer component (a), wherein the molar ratio between the butadiene and styrene monomers in said component (a) ranges from 90 to

10. preferably from 80 to 20, more preferably is 70 to 30.

11. A [dark pigmented] thermoplastic elastomer (TPE) composition of claim 10 wherein the styrene and butadiene monomers, are totally or partially replaced, respectively, by other vinylaromatic and 1, 3-conjugated diene monomers

12. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 11, which contains a SBS block copolymer component (a) , wherein the SBS block copolymer of said component (a) is partially or fully hydrogenated in the elastomeric block portion, on more than 80%, preferably more than 99% (mole%) of the total unsaturation .

13. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 12, which contains a SBS block copolymer component (a) wherein the styrene butadiene styrene (SBS) block copolymer of said component (a) is partially substituted by a polybutadiene polymer, a polyolefin elastomer such as ethylene/propylene copolymers up to 40% by weight, based on total weight of the composition.

14. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 13, which contains component (b) wherein the polyolefin elastomer of said component (b) is a metallocene polyolefin based on a ethylene/octene copolymer.

15. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 14, which contains component (c) where the thermoplastic polyurethane of said component (c) contains additives such a stablizers, surface active agents and foam stabilizers .

16. A dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 15, wherein the black pigment composition component (d) comprises at least 40 wt% of the total pigment used in the dark pigmented thermoplastic composition .

17. A dark pigmented thermoplastic elastomer (TPE) composition of claim 16, wherein the black pigment composition component (d) comprises greater than 60 wt% of the total pigment used in the dark pigmented thermoplastic composition.

18. A dark pigmented thermoplastic elastomer (TPE) composition of claim 17, wherein the black pigment composition component

(d) comprises greater than 70 wt% of the total pigment used in the dark pigmented thermoplastic composition.

19. A dark pigmented thermoplastic elastomer (TPE) composition of claim 17, wherein the black pigment composition component (d) comprises 100 wt% of the pigment added to the dark pigmented thermoplastic composition.

20. A dark pigmented thermoplastic (TPE) composition of any of claims 1 to 19, wherein the black pigment composition of component (d) is RENOL PV 90050120-BN/GUM, black master batch from carbon black free pigment composition into PE-EVA or RENOL NERO GVM CBF of Clarian Masterbatches S. P. A., Milan.

21. A footwear component formed from the dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 20.

22. An article comprising at least one component formed from the dark pigmented thermoplastic elastomer (TPE) composition of any of claims 1 to 20.