WO2001004208A1

WO2001004208A1 - Composition containing nbr and thermoplastic elastomer

Info

Publication number: WO2001004208A1
Application number: PCT/BR2000/000073
Authority: WO
Inventors: Maurício MOREIRA NUNES; Mauro Eduardo Costa Braz Pinto
Original assignee: Nitriflex S/A Indústria E Comércio
Priority date: 1999-07-13
Filing date: 2000-07-12
Publication date: 2001-01-18
Also published as: BR9902743C1; EP1161493A4; EP1161493A1; BR9902743A

Abstract

The present invention relates to an NBR copolymer and thermoplastic elastomer composition. The invention further relates to a pre-crosslinked NBR copolymer and thermoplastic elastomer composition, in which the NBR is pre-cosslinked by addition to the composition of a crosslinking monomer having a functionality equal or higher than 3, said crosslinking monomer being selected from divinyl benzene, trimethylol propane trimethacrylate, ethylene glycol dimethacrylate and triallyl isocianate. Said compositions are specially useful for shoes industry, toys, coifs, gaskets and any other article made of rubber. Said rubber produced according to the present invention exhibits improved mechanical, chemical and dull look properties.

Description

COMPOSITION CONTAINING NBR AND THERMOPLASTIC ELASTOMER

FIELD OF THE INVENTION The present invention refers to NBR copolymer thermoset elastomer compositions or mixtures, or NBR copolymers with a crosslinking agent, with the thermoplastic elastomers having improved surface and dullness or opacity properties. Application of these mixtures can be found in the shoes industry, that is, in shoe soles and similar, tubes and hoses, toys, coifs, gaskets and any other article made of rubber. The present invention also relates to vulcanizable NBR and thermoplastic elastomer copolymer or terpolymer mixtures or compositions. BACKGROUND OF THE INVENTION

It is common knowledge that vulcanized rubber and also thermoplastic rubber are used in shoe soles. However, the use of thermoplastic polymers results in a rubber with a brightness aesthetically not accepted by the shoe industry. These mixtures are generally constituted of thermoplastic elastomers such as SBR, SSBR, and so on with polybutadiene . Due resulting brightness in the final product, this would have to be further subjected to a dulling process to produce an aesthetically useful article for shoe soles. Besides brightness these rubbers have poor mechanical properties, such as processability, strain, elasticity, abrasion and elastomeric memory and other properties.

The elastomeric mixture technology is rapidly improving, mainly in the case of elastomeric mixtures to produce thermoplastic elastomers. All this shows that this tendency, named technology tendency will grow in the polymer industry. This means that less emphasis will be given to the development of new materials derived from totally new monomers. This means that from now on more improved materials formed from mixtures and composite materials, from known polymers will be produced.

Due to a need for obtaining a rubber with vulcanized rubber characteristics, without the disadvantages of the groups of thermoplastic rubbers of the prior art, the present inventors have concentrated their aim at the structural morphology of elastomeric materials, in an attempt to control physical, chemical, rheological and surface properties of thermoplastic materials. The main idea arised from the fact that most polymers, when mixed, wield two phases inside their morphology, this being predominant in all thermoplastics, as they are structured by "soft domain" (polybutadiene) and "hard domain" (styrene) . The polymer found in greater concentration would be the continuous phase with the second polymer soaked between them thus, forming a discrete continuous matrix. In 1962, Drs . Walter and Klyte demonstrated in their studies that most mixtures form small "heterogeneous" zones, with an extension of approximately 0,5μm. This extension zone is called "closing" or "pseudo - crosslinkage" . Due to this physical - chemical phenomenon, certain elastomeric behaviours can be found in these "thermoplastic" materials. However it has been proved that some of these mixtures or "high performance polymers" consist of small phases in "discrete zones", as described before. These phases are within a continuous matrix with a larger phase. Another outstanding feature occurs during the "inversion" of phases, which occurs when these "thin plates" have an extension of approximately 0,5μm of the fraction of the molecular interpenetrations between them, which brings up unpleasant effects to their physical and mechanical properties, such as : a. high module; b. high thermoplastic strain c. low abrasion resistance d. low tearing resistance e. plastic appearance

These are undesirable characteristics in thermoplastic elastomers for specific uses, as for example in shoe products.

The new studies developed here have demonstrated that large "inter - closing" zones depend, directly, on the volume fraction and the intrinsic viscosity relation of the used elastomers, that is, a main factor for the elastomeric mixtures to show physical and mechanical acceptable properties. All this depends on "inter facial linkage extensions", which occur between the used elastomers, in particular when they exhibit different reactivities, a phenomena observed when thermoplastic elastomers or mixtures undergo swelling tests (solvating) , in which only a portion of the elastomer swells, as the referred to elastomer portion does not show "inter - closing" with the other phase, due to the fact that is larger and continuous. Recent works have emphatically shown the obtainment of new mixtures for the thermoplastic elastomer production. Thermoplastic elastomer mixtures are characterised as materials, which can be processed when, submitted to friction and temperatures and, later, when they are cooled they show properties similar to the vulcanized elastomers .

When most thermoplastic elastomers are compounded or formulated, they must be assisted by additives such as: mineral fillers, plasticizing oils, antioxidants and high tenacity polymeric mixtures (high impact polystyrene) , to improve, as they say, their final properties, such as: abrasion, tearing and stiffness with the circunstancial reduction of their flow property, when using calcium carbonate and silica, thus requiring the use of 5 to 30 parts of high impact polystyrene in the formulation. Then the undesirable fact occurs. The discrete thermoplastic phase from the polystyrene with a lesser proportion in the diblocked elastomer (styrene butadiene) is increased in a disproportional way and the elastomeric phase of the polybutadiene is diminished. Addition of high impact polystyrene homopolymers, when aggregated to the diblocked polymers increase disproportionately the Yong modules, which normally, with the addition of plasticizing oils cause the reduction of these modules. Further it is worth to mention that the diblock SBS thermoplastics are very elastic during their softening in the process phase. This is due to the retention of the two phases and their "interclosed" structures above the glass transition temperature (T_g) of the blocked polystyrenes . Other disadvantage found in the prior art was the plastic's characteristic brightness over the surface of the finished product, mainly in shoe soles, as well as elastomeric memory loss. To prevent these undesirable effects on those products one uses polybutadiene thermoplastic elastomers with high syndiotacticity or with crosslinkage, which reduce the modules making them lower, improves their elastomeric properties and render them dull . These features cannot be found in all thermoplastics, when high impact polystyrenes are used therein. Due to this apparent deficiency there is a demand in the shoe industry for lighter and more practical new materials, such as thermoplastics, which would be the ideal candidates for an excellent productivity and a minimal possible loss (vulcanized cuttings) , increasing their versatility and diminishing the labor required for vulcanized elastomers. Thus, nowadays there is an incessant search for rubber articles in order to obtain the physical features described above, as well as the dullness in the final product.

To overcome those drawbacks of the prior art, the present inventors developed a rubber from a mixture of thermoplastic with NBR or a pre - crosslinked NBR, in which addition of NBR or pre - crosslinked NBR (NBR + monomer + crosslinked agent) provide dull thermoplastic elastomers. ABSTRACT OF THE INVENTION The present invention consists of a thermoset NBR copolymer polymeric elastomer composition or a NBR copolymer plus a crosslinking agent, with thermoplastic elastomers, wherein they exhibit improved mechanical and surface properties, as well as a final dull product. The present invention also refers to a vulcanizable polymeric composition.

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to provide a polymeric composition, comprising from 5 to 95 parts of NBR per 100 parts of the composition with thermoplastic elastomer.

Another object of the invention is to provide a polymeric composition comprising from 5 to 95 parts of NBR terpolymer - crosslinking agent per 100 parts of the composition with polymeric elastomer, in which the elastomer is selected from monoblocked, diblockerd, triblocked, radial or linear thermoplastic elastomers.

Another object of the invention is to provide a vulcanizable polymeric composition comprising from 5 to 95 parts of (NBR) butadiene-acrylonytrile copolymer or a terpolymer of butadiene-acrylonytrile-butadiene (NBR) - crosslinking monomer per 100 parts of the composition with thermoplastic elastomer and an effective amount of a vulcanized system. The crosslinking agent used in the composition is selected from monomers with a functionality equal or higher than 3. Preferably, the agents or crosslinking monomers are selected from divinyl benzene, trimethylol propane trimetacrylate, ethylene glycol dimetacrylate and triallyl isocianurate . In general, by elastomeric material it is meant the one, which can be drawn to 100% of its original size, without losing its return, that is, it returns to its original size in a short period of time. This effect has been observed in the compositions of the invention made from thermoplastic elastomers and NBR, with the difference that the modules diminish proportionally to the crosslinkage degree and' to the amount of acrylonitrile used in the NBR copolymer, which does not occur in thermoplastic elastomers without the presence of NBR.

Modified thermoplastic elastomers and thermoelastic mixtures exhibit strain/deformation features, this fact being proved in thermoplastic elastomers as they have low modules, typical of crosslinked elastomers (C curve) and other high modules producing materials undergo from a high degree of plastic deformation (B curve) .

GRAPH tensao: strain deformaςao: deformation A) HIGH PLASTIC MODULE

B) HIGH MODULE WITH POOR CYCLE RETURN

C) LOW ELASTOMERIC MODULE

By using the polymeric mixtures, physical properties can be altered thus, producing materials, which can be used in a great number of applications in several different industries.

Referring to the above mentioned, a profound study has led to polymer mixtures butadiene-acrylonitrile copolymer or butadiene-acrylonitrile-crosslinking monomer terpolymer and to vulcanizable polymeric mixtures, comprising butadiene-acrylonitrile copolymers or butadiene- acrylonitrile-crosslinking monomer terpolymer and a vulcanization system, which exhibit low module properties. The term "crosslinking monomer" includes conventionally known monomers in the art as polymerizable crosslinking agents, in combination with other traditional monomers. Typically, as mentioned above, these crosslinking monomers include monomers with a functionality equal or higher than 3, such as divinyl benzene, trimethylol propane trimethacrylate, ethylene glycol dimethacrylate and triallyl isocyanate, 1, 3 dimethacrylate butilene, alyl metacrylate, or any other crosslinking agent known from the art. In the present invention, the term "NBR copolymer or terpolymer of butadiene-acrylonitrile-crosslinking monomers agent" is simply called NBR. The polar acrylonytrile monomer content can vary from 1 to 60%, preferably from 5 to 50% and more preferably form 15 to 45% by weight based on the butadiene weight.; the crosslinking agent varies from 0 to 20%, preferably from 0 to 10% and more preferably from 0 to 5% by weight based on the weight of acrylonytrile and butadiene. These copolymers or terpolymers are capable of producing effects only presently found by using syndiotactic polybutadiene polymers when mixed with some blocked, diblocked, triblocked polymer thermoplastics (styrene butadiene - styrene, (SBS) , styrene - isoprene-butadiene- styrene (SSBS) , styrene - isoprene - butadiene - styrene (SIBS) , styrene- isoprene-styrene (SIS) , independently if they are linear or radial in their basic structure. NBR in the polymeric composition presents an excellent compatibility in concentrations from 5 to 50 parts, preferably from 5 to 40 parts, more preferably from 5 to 30 parts, and much more preferably from 5 to 20 parts per 100 parts of elastomer, exhibiting superior or equal physical and mechanical characteristics in different used proportions when compared with syndiotactic polybutadiene conventionally used in thermoplastic elastomer compositions, so as to produce the desired effects in the shoe industry, mainly when partially crosslinked NBR copolymers with shrinkage values between 0 and 15%, 0 and 20%, 0 and 30% or 0 and 40% are used. It has been clearly observed that these long branched chains were inter - closed with the base polymer providing an intermolecular linkage and thus forming a web between the thermoplastic elastomer discrete phases and the NBR copolymers. The thermoplastic elastomer final mixtures with varied NBRs present mechanical properties on the same level or superior to those produced by thermoplastic elastomers and syndiotactic polybutadiene. Syndiotactic polybutadiene is world-wide produced only by "Japan Synthetic Rubber Co.", and nowadays this company cannot supply the worldly demands. Customers from all over the world purchase such products under share regime, due to the fact that annual production of syndiotactic polybutadiene is not capable of attending the world requirements. It is also an object of the present invention to offer to the market an alternative to the shortage of this product, also providing the development of new applications of thermoplastic rubbers not so much explored until now.

The intermolecular linkages between thermoplastic elastomer matrix in combination with the intermolecular linkages of the butadiene-acrylonytrile-crosslinking monomer terpolymer, generate a crosslinked structure in three dimensions, which upon melting during the moulding step returns to its original position after melting. In this return the intermolecular linkages and the intramolecular linkages play fundamental role either in maintaining a good level of mechanical properties or in the dullness showed by the mixture. Crosslinkages withstand the melting process without tearing. Thus, after their post-melting cooling, these crosslinkages maintain the interclosed structures of the mixture stiffening the polymeric structure, now cold, thus producing a microscopic wrinkling on the artifact surface. This multifaceted surface on a microscopic level is responsible for the chaotically incident light refraction, exhausting the artifact brightness, so as to give it the final dull appearance. If there is not such a type of "anchoring" or "fastening" of chains, after their relaxing in the melting step, there is no sufficient elastic memory to pull these chains and create a superficial microwrinkling, responsible for the final dull appearance of the artifacts, after moulding.

The NBR /thermoplastic elastomer compositions of the present invention, as they have allyl carbons in both compounding basic polymers, in relation to the mere coming from butadiene, can also be submitted to the same conventional process steps as the non thermoplastic elastomers are submitted, i.e., they can be vulcanized with systems based on sulphur or its donors or with peroxide based systems, with or without the use of co-agents, then resulting in the polymeric composition mentioned before. Further, the present compositions can be moulded by conventional rubber industry processes.

Vulcanization system is selected from the following products conventionally utilised in the vulcanized rubber manufactures, such as: sulphur and/or its donors, primary accelerators, secondary accelerators, tertiary accelerators, peroxides, sylanes, crosslinking agents and their mixtures and electron accelerators.

In the present specification, the expression "efficient amount of vulcanizing system" means the amount routinely used in the field of vulcanized rubber manufacture. This amount will depend on the vulcanizing system used and also on the origin of the products employed in the vulcanizing system. These amounts are only given for illustrative purposes.

Sulphur based vulcanizing systems and/or its donors, in general, can be classified as in the following table : enxofre (S) : sulphur (S) acelerador (A) : accelerator (A) convencional : conventional semi - eficiente: half effective eficiente: effective

Conventional systems: give good flexion and wear resistance and optimum tearing resistance. The permanent compressive deformation (DPC) is poor.

Half effective systems: give optimum flexion and wear resistance, good heat resistance, medium permanent compressive deformation (DPC) . Effective systems: give low flexion and wear resistance. Excellent heat and permanent compressive deformation resistance (DPC) .

Other forms of intermolecular linkages, which should be mentioned are: * "Vulcanization" by organic or inorganic peroxides with or without using co-agents;

* Super accelerated electrons or diverse super accelerators are also possibly usable as a way of "vulcanizing" elastomers; The compositions of the invention can also comprise pigments, accelerators, cure agents, fillers, plasticizers, flux agents, anti oxidants, anti ozonants, cure co-agents and so on, selected under those conventionally used in the rubber production technique; The present invention will be illustrated, but not limited, by the following examples:

Reference example (1) - physical properties: In a double SCREW extrusion machine (L/D = 32; 40 mm) the following composition has been mixed: COMPONENTSphr

Kraton KX 224 ES¹60 Kraton KD 4270 BS²40 syndiotactic polybutadiene25 HI EDN 492 polystyrene12 , 5 Shellflex 451³15 Irganox 1010⁴ 0 , 2

¹ thermoplastic elastomer

² thermoplastic elastomer

³ plasticizing oil ⁴ antioxidant

After blending in the extrusion machine, the material was injected at 190 °C (Battenfelf extrusion machine BA 250/050 CDC) .

Results of the reference composition analysis are given in the table below.

PROPERTIES RESULTS

Abrasion DIN mm³236

Shore hardness A - 15 seconds 65.7

Density, g/cm³0.95 Flow index g/10 min (5 kg - 190 °C)3.65

Module @ 300%, Mpa3.65

Elongation in breaking, %435.0

Tension resistance, Mpa4.99

"dull - look" effect (opacity) standard Example 01 of the Invention:

The following composition was mixed in the same double screw extrusion machine (L/D = 32; 40 mm) : COMPONENTS phr Kraton KX 224 ES 60 Kraton KD 4270 BS40 acrylonytrile -butadiene copolymer 25 HI EDN 492 polystyrene 12.5 Shellflex 45115 Irganox 10100.2 After compounding in the extrusion machine, the material was injected at 190 °C (Battenfelf extrusion machine BA 250/050 CDC) .

Results of the reference composition analysis are given in the Table below. PROPERTIES RESULTS Abrasion DIN mm³258

Shore hardness A - 15 seconds61.5

Density, g/cm³0.96

Flow index g/10 min (5 kg - 190 °C) 18.60 Module @ 300%, Mpa3.62

Elongation in breaking, %453,9

Tension resistance, Mpa4,43

"dull - look" effect (opacity) standard

Example 02 of the Invention (physical properties) : The following composition was mixed in the same double screw extrusion machine (L/D = 32; 40 mm) :

COMPONENTS phr

Kraton KX 224 ES 60

Kraton KD 4270 BS 40 butadiene-acrylonytrile-crossling agent terpolymer 25

HI EDN 492 polystyrene 12.5

Shellflex 451 15

Irganox 10100,2 After compounding in the extrusion machine, the material was injected at 190 °C (Battenfelf extrusion machine BA 250/050 CDC) .

Results of the reference composition analysis are given in the Table below. PROPERTIES RESULTS

Abrasion DIN mm³234

Shore hardness A - 15 seconds64,2

Density, g/cm³0,96

Flow index g/10 min (5 kg-190°C) 18 , 80 Module @ 300%, Mpa3,72

Elongation in breaking, %432,2

Tension resistance, Mpa4,44

"dull - look" effect (opacity) above standard

Example 03 of the Invention (physical properties) : The following composition was mixed in the same double screw extrusion machine (L/D = 32; 40 mm) : COMPONENTS phr Kraton KX 224 ES 60 Kraton KD 4270 BS 40 butadiene-acrylonytrile-crosslinking agent terpolymer 35 HI EDN 492 polystyrene 12.5 Shellflex 451 15 Irganox 1010 0.2

After compounding in the extrusion machine, the material was injected at 190 °C (Battenfelf extrusion machine BA 250/050 CDC) .

Results of the reference composition analysis are given in the Table below.

PROPERTIES RESULTS Abrasion DIN mm³260 Shore hardness A - 15 seconds65.2 Density, g/cm³0.96 Flow index g/10 min (5 kg - 190 °C) 19.50

Module @ 300%, Mpa3.12 Elongation in breaking, %567.8 Tension resistance, Mpa3.96

"dull - look" effect (opacity) above standard The composites blended (mixed) with NBR copolymers or terpolymers, in combination with thermoplastic rubbers have a variety of applications, such as: Shoe Industry

1. solid soles for casual shoe (tennis, walking shoes)

2. expanded soles for casual shoe

3. soles for safety boots

4 . heels

5 . boot heels 6 . welts 7. insoles, as an additive for ethylene- vinylacetate (EVA) and the like

8. total or partial PVC substitution for injected boots for use in cold storage rooms Automotive Industry

1. extruded and expanded profiles for door sealing

2. sealings

3. dust covers for homo kinetic junctions (coifs)

4. retainer for motor carters exposed to temperature and lubricant oil action

5. hoses for hydraulic fluids (wheel and/or brakes)

6. total substitution of the windshield wiper

7. damper seats Toys and Sports Industry

1. cars

2. dolls made up by rotormoulding or injection

3. balls

4. pins 5. fitting parts

6. holding articles

7. injected tires for two wheel vehicles

8. paddles

9. snorkels 10. belts, air ducts and diving masks

11. watch belts Printing Industry

1. special drawing erasers

Hygienic and Personal Cleaning Industry 1. toothbrush handle (soft touch)

2. hairbrushes

3. combs

4. hair strips/clamps

5. raincoats 6. glass frames 7 . buckets

8. receptacles

9. ice forms

10. glasses Adhesive Industry

1. multi-utilisation adhesives for polar and non polar surfaces

Paint Industry / Building 1. underwater surface coverings 2. solvent based automotive paints stone resistant

3. airport and bridge paving expansion joints

4. water proof covers mixed with asphalt Electricity Industry

1. low voltage wire and cable coverings The blends (mixtures) , of the invention, present special properties and can be used in all above mentioned applications. Such applications are mentioned herein for as an example, illustrative purposes only.

The thermoplastic NBR rubber composite (TR) can be produced in many ways. The most usual is by mixing NBR powder with TR powder in speedy mixers, "Henschel" type or helical mixers, concrete mixers or also by simple drumming, which consists of physically mixing the two components in any type of drum, container, bucket, etc. After this step, the mixture can be added to any kind of extrusion machine, mono or double screw extrusion machine, co-rotating or counter-rotating, extruded, then pelletized for subsequent processing in thermoplastic transforming industry equipment. The final blended form, in powder, pellets, grumps, mats or wires is not obstructive nor restrictive for their posterior use and do not influence the final properties claimed in the artefact produced by them.

The utilisation of NBR as a dulling or opacity agent, besides presenting good dullness results, increase the solvent resistance of the final blend, as described in the examples below.

Reference Example 02 (chemical resistance of the blend) The following composition was mixed in the same double screw extrusion machine (L/D = 32; 40 mm) : COMPONENTS phr Kraton KX 224 ES 60 Kraton KD 4270 BS 40 syndiotactic polybutadiene 25

HI EDN 492 polystyrene 12,5 Shellflex 451 15 Irganox 1010 0,2

Results of the reference composition example 02 analysis are given in the Table below. PROPERTIES RESULTS swelling after ageing in hexane;

70 @ room temperature %+ 36.5 Swelling after ageing in cooking oil; 70h @ room temperature %+ 16.6 Swelling after ageing in fuel 2 7Oh @ room temperature %+ 21.6

Swelling after ageing in fuel 3 7Oh @ room temperature %+ 49,4 "dull look" effect (opacity) standard Example 04 of the Invention (chemical resistance of the blend)

The following composition was mixed in the same double screw extrusion machine (L/D = 32; 40 mm) : COMPONENTS phr Kraton KX 224 ES 60 Kraton KD 4270 BS 40 butadiene-acrylonitrile- crosslinking agent 25 HI EDN 492 polystyrene 12,5 Shellflex 451 15 Irganox 1010 0.2

Results of the reference composition example 04 analysis are given in Table below. PROPERTIES RESULTS swelling after ageing in hexane ; 70 @ room temperature %+ 16.7 Swelling after ageing in cooking oil; 70h @ room temperature %+ 2.3

Swelling after ageing in fuel 2 7Oh @ room temperature %+ 11.4 Swelling after ageing in fuel 3 7Oh @ room temperature %+ 21.7 "dull look" effect (opacity) standard

A comparison between the reference Example 02 and Example 04 of the invention clearly denotes the blend advantages, with NBR referring to the blends of the prior art, in the properties of resistance to several solvents. Another way of mixing the two compounds is by feeding them into normally used mixers employed in normally used mixers, used in the thermoset rubber-transforming industry, such as inner mixers "Banbury" or "Kneader" type, utilising Banburry or Sigma, Roller or Cam rotors or any other normally used rotor. Similarly, open cylinder mixers can also be successfully used to process the blend (mixture) of the invention. With the ready mixture, in any kind of mixing equipment largely used in the thermoset rubber industry, it can be processed afterwards in any kind of mono or double screw, co-rotational or counter-rotational extrusion machine, extruded and pelletized for subsequent processing in thermoplastics transforming industry equipment. With this same mixture, processed in thermoplastic rubber industry mixing equipment, in case adhesives and conventional additives components of said industry field are added, such as sulphur, vulcanization agents, primary accelerators, secondary accelerators, plasticizers, flow adjuvants, activators, fillers, antiozonants , antioxidants, etc., a vulcanizable composition can be obtained in any kind of equipment, such as simple presses or transferring presses, injection machines, autoclaves, vulcanizing tunnels, etc., which render superior final properties to the same products when employing the prior art techniques, notably in their solvent and abrasion resistance properties.

Reference Example 03 (vulcanized blend (mixture) )

In a LUXOR MBL 150 cylinder mixer the below mentioned components are added, in the following sequence:

COMPONENTS phr Kraton KX 224 ES 60

Kraton KD 4270 BS 40 syndiotactic polybutadiene 25

HI EDN 492 polystyrene 12.5

Shellflex 451 15 Ultrasil VN3 (silica) 25

Irganox 1010 0.2

Stearyne 1 , 0

Zinc oxide 3.0

Sulphur 1.4 MBTS 0.16

Santocure MOR 1.35

After compounding during 15 minutes @ 60 °C, test samples were vulcanized in specific moulds in a press, after the rheometric curve @ 160 ° . Results of the reference composition example 05 analysis are given in Table below.

PROPERTIES RESULTS

Abrasion DIN mm³231.0 Shore hardness A - 15 seconds 85,0

Swelling in oil ASTM 1: 72h+42,l

Room temperature %

Elongation in breaking, % 385.0

"dull - look" effect (opacity) standard Reference Example 05 (vulcanized blend (mixture) )

COMPONETS phr

Kraton KX 224 ES 60 Kraton KD 4270 BS 40 butadiene-acrylonitrile- crosslinking agent terpolymer 25

HI EDN 492 polystyrene 12,5

Shellflex 451 15 Ultrasil VN3 (silica) 25

Irganox 1010 0.2

Stearyne 1.0

Zinc oxide 3.0

Sulphur 1.4 MBTS 0.16

Santocure MOR 1.35

After compounding during 15 minutes @ 60 °C, test samples were vulcanized in specific moulds in a press, after the rheometric curve @ 160 °. Results of the reference composition example 05 analysis are given in Table below

PROPERTIES RESULTS

Abrasion DIN mm³197,0

Shore hardness A - 15 seconds81,0 Swelling in oil ASTM 1: 72h+18,l Room temperature % Elongation in breaking, %430.0 "dull - look" effect (opacity) like standard Dulling or opacity effect was maintained, with a lesser abraded volume and lesser swelling percentage, which denotes a blend with better properties than that of the prior art .

The composition of the invention presents a superior non-polar solvent resistance, compared with those compositions in which a polymer of the prior art is used.

Accordingly the composition of the invention is particularly appropriate for making parts, such as hoses, gaskets, sealings, coifs profiles, etc., in which a high organic solvent resistance is required. Although the invention has been described with reference to specific embodiments contemplated herein, it has to be understood that many modifications and alterations apparent to those skilled in the art, to which this invention belongs, can be performed, which fall within the scope of the invention as defined in the appended claims.

Claims

1. Polymeric composition CHARACTERIZED in that it comprehends 5 to 95 parts of butadiene-acrylonitrile copolymer (NBR) or butadiene-acrylonitrile (NBR) - crosslinking monomer terpolymer with 95 to 5 parts of thermoplastic elastomer per 100 parts of the composition; wherein the crosslinking monomer is selected from those having a functionality > 3 and said thermoplastic elastomers are selected from monoblocked, diblocked, triblocked, radial or linear.

2. Composition of claim 1, CHARACTERIZED in that it comprised more preferably from 5 to 95 parts of butadiene-acrylonitrile copolymer or butadiene-acrylonitrile crosslinking monomer terpolymer per 100 parts of the said thermoplastic elastomer composition.

3. Composition of claim 2, CHARACTERIZED in that it comprises more preferably from 5 to 80 parts of butadiene-acrylonitrile copolymer or butadiene- acrylonitrile-crosslinking monomer terpolymer per 100 parts of said thermoplastic elastomer composition.

4. Composition of claim 3, CHARACTERIZED in that it comprises more preferably from 5 to 70 parts of butadiene-acrylonitrile copolymer or butadiene- acrylonitrile-crosslinking monomer terpolymer per 100 parts of said thermoplastic elastomer composition.

5. Composition of claim 1, CHARACTERIZED in that the crosslinking monomer preferably comprises divinyl benzene, trimethylol propane trimethacrylate, ethylene glycol dimethacrylate and triallyl isocianate.

6. Composition of claim 1, CHARACTERIZED in that said acrylonytrile monomer varies from 1 to 60% by weight, based on the weight of butadiene and acrylonitrile monomers of the NBR.

7. Composition of claim 6, CHARACTERIZED in that, preferably, said acrylonytrile monomer varies between 15 to 45% by weight, based on the weight of butadiene and acrylonitrile monomers of the NBR.

8. Composition of claim 1, CHARACTERIZED in that said crosslinking monomer is present in an amount ranging from 0 to 20% by weight based on the weight of butadiene and acrylonitrile monomers of the NBR.

9. Composition of claim 8, CHARACTERIZED in that said crosslinking monomer is preferably present in an amount ranging from 0 to 10% by weight based on the weight of butadiene and acrylonitrile monomers of the NBR.

10. Composition of claim 9, CHARACTERIZED in that said crosslinking monomer is present in an amount ranging preferably from 0 to 5% by weight based on the weight of butadiene and acrylonitrile monomers of the NBR.

11. Composition of claim 1, CHARACTERIZED in that said thermoplastic elastomer is selected from styrene butadiene - styrene, (SBS) , styrene - isoprene - butadiene - styrene (SIBS) , styrene - isoprene-butadiene-styrene (SSBS) , styrene- isoprene -styrene (SIS) .

12. Composition of any of claims 1 to 11,

CHARACTERIZED in that the final article produced by said composition presents a dull-look (opacity) .

13. Composition of any of claims 1 to 12, CHARACTERIZED in that it can further comprises pigments, plasticizers , flow agent, antioxidants and antiozonants .

14. Composition of any of claims 1 to 13, CHARACTERIZED in that it has a superior non-polar solvent resistance .

15. Polymeric vulcanizable composition CHARACTERIZED in that it comprises 5 to 95 parts of butadiene-acrylonitrile copolymer (NBR) or butadiene- acrylonitrile (NBR) -crosslinking monomer terpolymer with 95 to 5 parts for thermoplastic elastomer per 100 parts of said composition and an effective amount of vulcanizing system; wherein said crosslinking monomer is selected from those having a functionality > 3 and said thermoplastic elastomers are selected from monoblocked, diblocked, triblocked, radial or linear of vulcanising system.

16. Composition of claim 15, CHARACTERIZED in that it comprises more preferably from 5 to 95 parts of butadiene-acrylonitrile copolymer or butadiene- acrylonitrile-crosslinking monomer terpolymer per 100 parts of said thermoplastic elastomer composition.

17. Composition of claim 16, CHARACTERIZED in that it comprises more preferably from 5 to 80 parts of butadiene-acrylonitrile copolymer or butadiene- acrylonitrile-crosslinking monomer terpolymer per 100 parts of said thermoplastic elastomer composition.

18. Composition of claim 17, CHARACTERIZED in that it comprises more preferably from 5 to 70 parts of butadiene-acrylonitrile copolymer or butadiene- acrylonitrile-crosslinking monomer terpolymer per 100 parts of said thermoplastic elastomer composition.

19. Composition of claim 15, CHARACTERIZED in that said crosslinking monomer preferably comprises divinyl benzene, trimethylol propane trimethacrylate, ethylene glycol dimethacrylate and triallyl isocyanate.

20. Composition of claim 15, CHARACTERIZED in that said acrylonytrile monomer varies from 1 to 60% by weight based on the weight of butadiene and acrylonitrile monomers of the NBR.

21. Composition of claim 20, CHARACTERIZED in that, preferably, said acrylonytrile monomer varies from 15 to 45% by weight based on the weight of butadiene and acrylonitrile monomers of the NBR.

22. Composition of claim 15, CHARACTERIZED in that said crosslinking monomer is present in an amount ranging from 0 to 20% by weight based on the weight of butadiene and acrylonitrile monomers of the NBR.

23. Composition of claim 22, CHARACTERIZED in that said crosslinking monomer is preferably present in an amount ranging from 0 to 10% by weight based on the weight of butadiene and acrylonitrile monomers of the NBR.

24. Composition of claim 23, CHARACTERIZED in that the crosslinking monomer is preferably present in an amount ranging from 0 to 5% by weight based on the weight of butadiene and acrylonitrile monomers of the NBR.

25. Composition of claim 15, CHARACTERIZED in that said thermoplastic elastomer is selected from styrene- butadiene-styrene, (SBS) , styrene-isoprene-butadiene-styrene (SIBS) , styrene-isoprene-butadiene-styrene (SSBS) , styrene- isoprene-styrene (SIS) .

26. Composition of any of claims 15 to 25, CHARACTERIZED in that the final article produced by the composition presents a dull-look (opacity) .

27. Composition of any of claims 15 to 26, CHARACTERIZED in that it can further comprised pigments, plasticizers, flow agent, antioxidants and antiozonants .

28. Composition of any of claims 15 to 27,

CHARACTERIZED in that it has a superior non-polar solvent resistance .

29. Composition of claim 15, CHARACTERIZED in that the vulcanization system is selected from sulphur and/or its donor, primary accelerators, secondary accelerators, tertiary accelerators, peroxides, silanes, crosslinking agents and mixtures thereof and also electron accelerators.