MXPA99007886A - Hydrosilylation cross-linking of thermoplastic elastomer - Google Patents

Abstract

In the preparation of thermoplastic elastomers by hydrosilylation cross-linking of the elastomeric component, the use of an elastomer containing a non-conjugated diene and having a Mooney viscosity within the MST range of 45 to 100 provides products with a high level of cross-linking and an improved combination of physical properties. This improvement is obtained even at low concentrations of hydrosilylation catalyst.

Description

INTERLATING THERMOPLASTIC ELASTOMER BY HIDROSILILATION BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention relates to thermoplastic elastomer compositions prepared using enrosing by hydrosilylation of the elastomer component of the composition. A thermoplastic elastomer is generally defined as a polymer or polymer blends that can be processed and recycled in the same way as a conventional thermoplastic material, however, it has properties and functional performances similar to those of vulcanized rubber at service temperatures. Plastic or rubber elastomeric mixtures or alloys have become important in the production of high performance thermoplastic elastomers, particularly for the replacement of thermosetted rubbers in various applications. High performance thermoplastic elastomers in which highly vulcanized rubber polymers are intimately dispersed in a thermoplastic matrix are generally known as thermoplastic vulcanizates.

DESCRIPTION OF THE RELATED TECHNIQUE Polymer blends having a combination of both thermoplastic and elastic properties are generally obtained by combining a thermoplastic resin with an elastomeric composition in such a way that the elastomer component is dispersed intimately and uniformly in a discrete phase in the form of particles within a continuous phase of the thermoplastic. The first works with vulcanized rubber components are found in the patent of E.U.A. No. 3,037,954 which describes both the static vulcanization of the rubber, as well as the dynamic vulcanization technique where a vulcanizable elastomer is dispersed in a resinous thermoplastic polymer in the molten state and an elastomer is cured while continuously mixing and being subjected to shear stresses to the mixture. The resulting composition is a micro-gel dispersion of the cured elastomer in an uncured matrix of thermoplastic polymer. In the patent of E.U.A. No. Re. 32,028 describes the polymer blends comprising an olefin thermoplastic resin and an olefin copolymer, wherein the rubber is dynamically vulcanized to a partial state of cure. The resulting compositions can be reprocessed. The Patents of E.U.A. Nos. 4,130,534 and 4,130,535 further describe thermoplastic vulcanizates comprising butyl rubber and polyolefin resin, and olefin rubber and polyolefin resin, respectively. The compositions are prepared by dynamic vulcanization and the rubber component is cured to the point of becoming essentially insoluble in conventional solvents. A scale of entanglement or cure agents for rubber vulcanization is described in the prior art, including peroxides, sulfur, phenolic resins, radiation, and the like. The Patent of E.U.A. No. 4,803,244 generally discloses the use of multifunctional organosilicon compounds together with a catalyst as an agent for crosslinking the rubber component of a thermoplastic elastomer by means of hydrosilylation. Hydrosilylation involves the addition of a silicon hydride through a multiple bond, often with a transition metal catalyst. This patent discloses a radium-catalyzed hydrosilylation of EPDM rubber in a mixture with polypropylene to produce thermoplastic elastomers having a gel content above 34% (after correction for the plastic phase). This degree of vulcanization was achieved only with a high catalyst level. A further description of the hydrosilylation entanglement of rubber in a thermoplastic elastomer composition is found in U.S. Pat. No. 5,672,660. The platinum catalyzed hydrosilylation of EPDM rubber containing 5-vinyl-2-norbornene as a diene monomer is disclosed.

BRIEF DESCRIPTION OF THE INVENTION The present invention is based on the discovery that the process for the hydrosilylation of the rubber in a thermoplastic elastomer can be improved by employing an ethylene as rubber., α-olefin, non-conjugated diene elastomeric polymer containing vinyl norbornene as a diene component. More particularly, it has been found that when the Mooney viscosity, the ethylene content and the diene content of this rubber are within the defined scales, unexpectedly low concentrations of the hydrosilylation agent and catalyst will completely cross over the excellent physical properties and the resistance to oil. In addition, the ethylene, α-olefin, non-conjugated diene elastomeric polymer of the invention on which the blends are based with thermoplastic resins will generally have low levels of diene to achieve similar or improved properties, when compared to the blends made. of ethylene, α-olefin, previously available non-conjugated diene elastomeric polymers. The previously available elastomers contained a diene selected from 5-ethylidene-2-norbornene, 1,4-hexadiene, dicyclopentadiene, or combinations thereof and compounds derived therefrom. The combination of low diene content and lower catalysts needs to have better properties for heat aging, UV stability and color capacity.

Compositions produced by the improved process have utility as replacements for thermosetting rubber compounds in a variety of applications, particularly where molding or extrusion is involved and the combination of thermoplastic and elastomeric properties provide an advantage. Typical uses include molded articles for parts under the hood of automobiles, engineering and construction materials, mechanical rubber materials, industrial parts such as hoses, pipes and gaskets, electrical appliances and household items.

DESCRIPTION OF THE PREFERRED MODALITIES The thermoplastic elastomer compositions can generally be prepared by mixing a thermoplastic resin and a rubber, subsequently melting the thermoplastic component and mixing the melt until the mixture is homogeneous. If a vulcanized rubber composition in a thermoplastic matrix is desired, the crosslinking agents (also referred to as curative or vulcanized agents) are added to the mixture and entanglement occurs during mixing under heat and shear conditions. This last procedure is described as dynamic vulcanization.

Thermoplastic resins A wide variety of thermoplastic resins and / or their blends have been used in the preparation of thermoplastic elastomers, including polypropylene, polypropylene copolymers, HDPE, LDPE, VLDPE, LLDPE, polyethylene copolymers, cyclic olefin homopolymers or copolymers as well as also olefinic block copolymers, polystyrene, polyphenylene sulfide, polyphenylene oxide and thermoplastics of ethylene-propylene copolymer (EP). Useful thermoplastic resins in the compositions produced by the invention include crystalline and semi-crystalline polyolefin homopolymers and copolymers. They are prepared from monoolefinic monomers having from 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-penten and the like, as well as copolymers derived from cyclic and linear olefins with propylene are also preferred. As used in the specification and claims, the term "polypropylene" includes propylene homopolymers as well as polypropylene reactor copolymers which may contain from about 1 to about 20% by weight of ethylene or α-olefin comonomer of 4 to 20 carbon atoms, and mixtures thereof. The polypropylene can be atactic, isotactic or syndiotactic, made with Ziegler-Natta or metallocene catalyst. The commercially available polyolefins can be used in the practice of the invention. Other thermoplastic resins that are substantially inert to rubber, silicon hydride and hydrosilylation catalyst may also be suitable. The thermoplastic resin blends can also be used. The amount of thermoplastic resin found to provide useful compositions is generally from about 5 to about 90% by weight, based on the weight of the rubber and the resin. Preferably, the thermoplastic resin content may vary from about 20 to about 80 weight percent of the total polymer.

Rubber In the present invention an ethylene, α-olefin, non-conjugated diene elastomeric polymer containing vinyl norbornene as a diene component is used as a rubber component. This contains about 40 to about 85 weight percent ethylene, preferably about 45 to about 80 weight percent, and most preferably in the range of about 50 to about 75 weight percent. The rubber component is contained on the scale of about 0.25 to about 5 weight percent of diene, preferably about 0.25 to about 2 weight percent, and most preferably on the scale of about 0.5 to about 1.2 weight percent. cent in weight. The remainder of ethylene, α-olefin, non-conjugated diene elastomeric polymer will usually be made of an α-olefin, selected from propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-ketene, 1 -decene and combinations thereof and the like. The preferred α-olefin is propylene. The elastomeric polymer has a Mooney viscosity, which was measured without oil in the polymer using ASTM D1646 with a small thin rotor (small, thin, Mooney-MST), generally on the scale of MST (5 + 4) at 200 ° C of about 45 to about 100, preferably on the scale of about 50 to about 90 and most preferably on the scale of about 50 to about 85. MST values above 100 are also contemplated as long as the polymer remains substantially gel free The polymer will have a branching index (Bl) generally in the range of about 0.1 to about 1.0, preferably in the range of about 0.3 to about 1.0, and most preferably in the range of about 0.5 to about 1.0. The elastomeric polymer will have an MwGPC, LALLS / MnGPC.DRI below about 20, preferably below about 10 and most preferably below about 8. In the preparation of the compositions of the invention, the amount of rubber it generally ranges from about 95 to about 10 weight percent, based on the weight of the rubber resin and the thermoplastic resin. Preferably, the rubber content will be on the scale of about 80 to about 20 weight percent of the total polymer.

Method for producing rubber Ziegler's polymerization of the vinyl norbornene double bond is believed to produce highly branched ethylene, α-olefin, vinyl norbornene elastomeric polymer. This branching method allows the production of such substantially gel-free elastomeric polymers that would normally be associated with ethylene, α-olefin, cationically branched non-conjugated diene elastomeric polymer containing, for example, unconjugated diene selected from a group consisting of 5-ethylidene-2-norbomeno (ENB), 1,4-hexadiene and the like. The synthesis of ethylene, α-olefin, vinyl norbornene elastomeric polymers substantially free of gel is discussed in Japanese patent applications JP 151758 and JP 210169, which are incorporated by reference herein for the purposes of the practice of the US patent Preferred embodiments of the aforementioned documents for synthesizing polymers suitable for this invention are described below. The catalysts that were used are VCI (vanadium tetrachloride) VOCI, (vanadium oxytrichloride) the latter as the preferred catalyst. The co-catalyst is selected from (i) ethylaluminum sesquichloride (SESQUI), (ii) diethylaluminum chloride (DEAC) and (iii) a 4/1 molar mixture of diethylaluminum chloride to triethylaluminum (TEAL). SESQUI is the preferred co-catalyst. The polymerization is carried out in a continuous stirred tank reactor at 20-65 ° C at a residence time of 6-15 minutes at a pressure of 7 kg / cm2. The molar concentration of vanadium to alkyl is from about 1 to 4 to 1 to 10. About 0.3 to 1.5 kg of polymer is produced per gram of the catalyst that is fed into the reactor. The concentration of the polymer in the hexane solvent is in the range of 3-7 weight percent. Other catalysts and co-catalysts may be used, some of which are described in the U.S. Patent. No. 5,153,282. The metallocene catalysts of the above monomers are also contemplated. This catalyst system includes group IV transition metal compounds and compounds capable of activating these compounds to an active catalyst state. Suitable activators include the ionized uncoordinated anionic precursor and alumoxane activation compounds, both known and described in the field of metallocene catalysis. Additionally, an active ionic catalyst composition comprises a cation of a transition metal compound of group IV and a non-coordinating anion resulting from the reaction of the transition metal compound of group IV with the non-coordinating anion precursor of ionization. The activation reaction is suitable if the anion precursor ionizes the metallocene, typically by the abstraction of Ri or R2 by any method including a protonation, ammonium or ionization of carbonium salt, ionization of metal cation or ionization of Lewis acid. The critical characteristic of such activation is the cationization of the group IV transition metal compound and its ionic stabilization by a resulting compatible, non-coordinating, or weakly coordinating anion (included in the non-coordinating term) capable of being displaced by the copolymerizable monomers. See, for example, EP-A 0277 003, EP-A 0 277 004, Patent of E.U.A. No. 5,198,401, U.S. Patent No. 5,241, 025, U.S. Patent. No. 5,387,568. WO 91/09882, WO 92/00333, WO 93/11172 and WO 94/03506 which are directed to the use of the non-coordinating anion precursors with the group IV transition metal catalyst compounds, their use in the polymerization processes and means to support them to prepare heterogeneous catalysts. Activation by alumoxane compounds, typically alkylalumoxanes, is still less defined in its mechanism, however it is well known for use with the catalysts of the group IV transition metal compound see for example US Pat. 5, 096,867. Each of said documents is incorporated by said reference for purposes of the practice of the U.S. Patent. The polymers prepared by said methods had the following molecular characteristics: The inherent viscosity measured in decalin at 135 ° C was found on the scale of 2-6 dl / g. The molecular weight distribution (MW.LANS'M? GPCDRP) was 4. The branching index was found on the scale of 0.3-0.7. The branching in ethylene, α-olefin, monomer diene polymers was quantified using a branching index factor. The calculation of this factor requires a series of three laboratory measurements of polymer properties in solution. The above are: (i) weight average molecular weight measured using the low angle light distribution technique (LALLS); (ii) weight average molecular weight and inherent viscosity using a differential refractive index (DRI) detector; and (iii) inherent viscosity (IV) measured in decalin at 135 ° C. The first two measurements are obtained in a GPC using a filtered diluted solution of the polymer in trichlorobenzene. An average branch index is defined as: Bl = (Mv. R / Mw. DRI / Mv. DRI) (I) Where Mv. r = k (IV) 1 / a; And "a" is the constant Mark-Houwink (= 0.759 for ethylene, -olefin, monomer diene in decalin at 135 ° C. From the equation (1) it is observed that the branching index for a linear polymer is 1.0, and for branched polymers the branching extension is defined relative to the linear polymer, although a branched Mn (Mw) constant (Mw)? neai Bl for a branched polymer is less than 1.0, and a value of Bl lower denotes a higher level of branching.The selection of catalyst will influence the MWD, with more highly branched polymers produced by VCI.The synthesis of ethylene, α-olefin, as polymers of norbornene vinyl was carried out in a laboratory pilot unit (output of approximately 4 kg / day), a large-scale semi-working unit (output approximately 1 T / day) and a plant scale of approximately 300 T / day.

Hydrosilylation agents Hydrosilylation has been described as an entanglement method. In said method a silicon hydride having at least two SiH groups in the molecule is reacted with the carbon-carbon multiple bonds of the unsaturated rubber component (eg, containing at least one carbon-carbon double bond) of the elastomer thermoplastic, in the presence of the thermoplastic resin and a hydrosilylation catalyst (the silicon hydride compounds useful in the process of the invention include methylhydrogen polysiloxanes, dimethyl siloxane copolymers of methylhydrogen, alkylmethyl methylhydrogen polysiloxanes, (dimethylsilyl) alkanes and bis (dimethylsilyl) benzene The amount of a silicon hydride compound useful in the process of the present invention may vary from about 0.1 to about 10.0 moles of SiH equivalents by the carbon-carbon double bond in the rubber, and preferably it is on the scale of about 0.5 to about 5.0 moles of SiH equivalents by the carbon-carbon double bond in the rubber component of the thermoplastic elastomer.

Hydrosilylation catalysts It has been previously understood that any catalyst, or catalyst precursor capable of generating a catalyst in situ, which will catalyze the hydrosilylation reaction with the carbon-carbon bonds of rubber may be used. Said catalysts have included group VIII transition metals such as palladium, rhodium, platinum and the like, including complexes of said metals. Chloroplatinic acid has been described as a useful catalyst in the U.S. Patent. No. 4,803,244 and Patent of E.U.A. number ,597,867, further disclosing that the catalyst can be used at concentrations of 5 to 10,000 parts per million by weight and 100 to 200,000 parts per million by weight based on the weight of rubber, respectively. It has been discovered in the process of the present invention that significantly lower concentrations of the platinum-containing catalyst can be used, while an improvement in the reaction rate and the efficiency of the entanglement is obtained. Catalyst concentrations in the range of about 0.01 to about 20 parts per million by weight, expressed as platinum metal, are effective in rapidly and completely curing the rubber in the process of the hydraulic vulcanization blends of thermoplastic resin and rubber. Catalyst concentrations of about 0.1 to about 4 parts per million by weight based on the weight of the rubber, expressed as platinum metal, are particularly preferred.

Platinum-containing catalysts that are useful in the process of the invention are described, for example, in the E.U.A. number 4,578,497; Patent of E.U.A. 3,220,972; and Patent of E.U.A. No. 2,823,218, which are incorporated herein by this reference. Such catalysts include chloroplatinic acid, chloroplatinic acid hexahydrate, complexes of chloroplatinic acid with sim-divinyltetramethyldisiloxane, dichloro-bis (triphenylphosphine) platinum (II), cis-dichloro-bis (acetonitrile) (II) platinum, dicarbonyldichloroplatinum (II) ), platinum chloride and platinum oxide. Zero-valent platinum metal complexes such as the Karstedt catalyst are particularly preferred, as described in the U.S. Patent. number 3,775,452; Patent of E.U.A. number 3,814,730; and Patent of E.U.A. No. 4,288,345, which are incorporated herein by reference.

Additives The thermoplastic elastomer may contain conventional additives, which may be introduced into the composition in the thermoplastic resin, the rubber, or in the mixture before or during, or after hydrosilylation and curing. Examples of such additives are antioxidants, processing aids, reinforcing and non-reinforcing fillers, pigments, waxes, rubber processing oil, oils to spread the rubber, anti-blocking agents, antistatic agents, ultraviolet stabilizers, plasticizers (including esters), foaming agents, flame retardants and other auxiliary products. processing known for the rubber composition technique. Said additives may comprise from about 0.1 to about 300 weight percent based on the weight of the final thermoplastic elastomer product. The fillers and extenders that can be used include conventional inorganics such as calcium carbonate, clays, silica, talcum, titanium dioxide, carbon black and the like. Additives, fillers or other compounds that can interfere with hydrosilylation should be added after the cure reaches the desired level.

Oil to extend the rubber The processing of rubber or oils to spread the rubber used in thermoplastic elastomers are generally paraffinic, naphthenic or aromatic oils derived from petroleum fractions. The type will be that ordinarily used in conjunction with the rubber or specific rubbers present in the composition, and the amount based on the total rubber content of the thermoplastic elastomer can vary to several hun percent rubber. It is important for the effectiveness of the catalyst that the oils and other additives do not contain or have very low concentrations of compounds that are catalyst inhibitors or that interfere with the activity of the catalyst. Such compounds include phosphines, amines, sulfides, thiols and other compounds that can be classified as Lewis bases. Lewis bases, or other compounds that have a pair of electrons available for donation, will react with the platinum catalyst, effectively neutralizing their activity. It has been found that the presence of such compounds has a surprising detrimental impact on the cure of hydrosilylation in the processes of dynamic vulcanization of the rubber component of the thermoplastic elastomer compositions. If the concentration of compounds that have the chemical reactivity of bases Lewis, said sulfur or nitrogen containing compounds are maintained at or below said level which provides less than about 1000 ppm and 300 ppm sulfur and nitrogen respectively, then the amount of platinum catalyst required to promote the hydrosilylation cure efficient in dynamic vulcanization can be substantially reduced, commonly in the range of about 4 ppm or less, without impacting the rubber curing state or the tensile properties of the thermoplastic elastomer product. Sulfur and nitrogen concentrations below about 500 and 200 ppm respectively are most preferred, and concentrations of less than about 30 ppm sulfur and less than about 100 ppm nitrogen are most preferred. It has been found that, even though the catalyst concentrations are 0.25 ppm, the total cure of the elastomer can be achieved if the concentration of sulfur and nitrogen is within the most preferred scales. The most paraffinic petroleum oils for the rubber industry are derived from a distillation stream of crude oil. A typical refining history may include some type of dewaxing to reduce the pour point, a solvent extraction to physically remove the aromatic compounds and a hydrotreating process to chemically modify the aromatic structures. Extraction and hydrotreating result in a net increase in the total concentration of saturated hydrocarbon structures and a net reduction in the concentration of the sulfur-containing compound and total aromatic nitrogen. The degree of reduction in the concentration of said compounds in the oil depends on the type and severity of the refining used, and on the nature of the crude oil. White and paraffinic oils have been treated more extensively than aromatic and naphthenic oils and may contain a lower concentration of aromatic, sulfur and / or nitrogen compounds. It is difficult to clarify the exact chemical structure of these compounds due to their complexity. The tendency of an oil to interfere with the catalyzed hydrosilylation of platinum is directly related to the concentration of the compounds containing sulfur and nitrogen, as well as compounds containing phosphorus, tin, arsenic, aluminum and iron.

Processing The rubber component of the thermoplastic vulcanizate generally appears as small, that is, in microtable particles in a continuous thermoplastic resin matrix, although a co-continuous morphology or a phase inversion depending on the amount of rubber is also possible. relation to the plastic and the degree of cure of the rubber.

The rubber is desirably intertwined at least partially, and preferably is completely or completely entangled. It is preferred that the rubber is interlocked by dynamic vulcanization process. As used in the specification and claims, the term "dynamic vulcanization" refers to the vulcanization or cure process for a molten rubber with a thermoplastic resin, wherein the rubber is vulcanized under cutting conditions at a temperature at which it will flow. mix. The rubber in this way is intertwined and dispersed simultaneously in the form of fine particles within the thermoplastic resin matrix, although as previously stated other morphologies may exist. Dynamic vulcanization is carried out by mixing the components of the thermoplastic elastomer at elevated temperatures in conventional mixing equipment such as roller mills, Banbury mixers, Brabender mixers, continuous mixers, mixing extruders and the like. The unique feature of the dynamically cured compositions is that, despite the fact that the rubber component is partially or completely cured, the compositions can be processed and reprocessed by conventional plastic processing techniques such as extrusion, injection molding. and compression molding. Fragmentation or reheating can be recovered and reprocessed. The terms "fully vulcanized" and "fully cured" or "fully entangled" as used in the specification and claims mean that the rubber component to be vulcanized has been cured or cross-linked to a state in which the elastomeric properties The cross-linked rubber are similar to those of rubber in its conventional vulcanized state, in addition to the composition of the thermoplastic elastomer. The degree of cure can be described in terms of gel content, or, conversely, extractable components. The gel content reported as a percent gel (based on the weight of the crosslinkable rubber) is determined by a method comprising the determination of the amount of the insoluble polymer by soaping the specimen for 48 hours in organic solvent at room temperature, weighing the dry residue and making the appropriate corrections based on the knowledge of the composition. In this way, the corrected initial and final weights are obtained by subtracting the initial weight the weight of the soluble components, different from the rubber to be vulcanized, such as oil to spread the rubber, plasticizers and components of the soluble composition. in organic solvent, as well as the rubber component of the product that is not intended to cure. Any insoluble polyolefins, pigments, fillers and the like are subtracted from the initial and final weights. The rubber component can be described as fully cured when less than about 5%, and preferably less than about 3% of the rubber that is capable of being cured by hydrosilylation is extracted from the thermoplastic elastomer product by a rubber solvent. Alternatively, the degree of cure can be expressed in terms of interlacing density. All these descriptions are well known in the art, for example in the Patents of E.U.A. Nos. 4,593,062.5,100,947 and 5,157,081, which are hereby incorporated by reference in their entirety. The following general procedure was used in the preparation of thermoplastic elastomers by the process of the invention, as described in the examples. The thermoplastic resin and the rubber spread with oil were placed in an internally heated mixer, with the hydrosilylation agent and the hydrosilylation catalyst. The hydrosilylation agent and the catalyst can be incorporated into the composition by any suitable technique, for example by injection as solutions in oil or as clear components, although a dilute catalyst solution is preferred. Additives such as antioxidants, ultraviolet stabilizers and fillers can also be added as an oil suspension. The master mixtures of the components can also be prepared to facilitate the mixing process. The mixture was heated to a temperature sufficient to melt the thermoplastic component, and the mixture was chewed with added processing oil if desired, up to a maximum of mixing torque indicating that the vulcanization had occurred. The mixing was continued until the desired degree of vulcanization was achieved. The invention will be understood even better with reference to the following examples that serve to illustrate but not stop limiting the current procedure. In the examples, the following test methods were used to determine the properties of elastomer thermoplastic products.

Hardness (Shore A) ASTMD 2240 Ultimate tensile strength (UTS-kg / cm2) ASTMD 412 Ultimate lengthening (UE-%) ASTMD 412 Module at 100% elongation ASTMD 412 (M1 -Kg / cm2) Stress fixation (TS- %) ASTMD 412 Oil increase (OS-%) ASTMD 471 (IRM 903 oil at 125 ° C for 24 hours) The rubber component used in the compositions prepared according to the examples was further identified in the following manner (compositions expressed as weight percent). The remaining monomer is propylene.

HULE Ethylene VNB Moonev.MST) Catalyst A 62.7 0.1 73.9 VOC13 M 58.4 2.4 55.0 VOCI3 The compositions were prepared as described above, using polypropylene resin and EPDM rubber containing vinyl norbornene as a diene monomer. A masterbatch composition was prepared containing 100 parts of rubber, 100 parts of oil to spread the paraffin rubber, 42 parts of clay (leecap K) and 41 parts of polypropylene. This mixture was mixed in a Brabender mixer at 180 ° C until the polypropylene melted. Silicone hydride was added to the mixture (3 phr) by dripping, followed by the addition of an oil solution containing platinum catalyst at several levels. The rubber was dynamically vulcanized by mixing the mixture until the maximum torque was reached. Additional processing oil was added after curing. The product was removed from the mixer, then returned to the mixer and chewed at 180 ° C for one additional minute. The test specimens were prepared by compression molding the products at 200 ° C, and the physical properties were determined. The results are shown in the following table.

PICTURE Example Rubber Catalyst Hardness UTS Alarming M1 TS OS (ppm Pt) (A) (kg / cm2 (%) (kg / (%) (%)) cm2) 1 A 0.25 53 41.05 692 16.23 11.5 327 0.35 54 47.24 696 17.22 10 300 0.5 56 49.49 616 19.61 9.5 239 1 58 54.06 568 22.21 9.5 196 2 B 0.25 44 23.97 183 17.36 13.5 201 035 47 30.36 195 20.45 12 175 0.5 47 27.48 200 17.43 11.5 171 1 55 44.57 215 24.32 9 128 3 C 0.25 50 33.74 225 20.52 10.5 179 035 51 37.61 188 24.60 10 159 0.5 53 43.51 227 24.04 8.5 136 1 57 51.31 220 26.85 8 1 1 1 4 D 0.25 50 26.71 219 20.31 14.5 227 035 53 41.05 286 21.93 10.5 188 0.5 54 44.99 294 22.00 9.5 151 1 58 52.51 257 26.78 8.5 126 E 0.25 60 66.78 400 27.41 8 105 035 61 66.08 430 26.01 7 103 0.5 61 67.48 350 31.63 6 92 1 60 66.78 340 30.93 6 94 6 F 0.25 62 66.78 390 28.12 8 102 035 61 64.67 340 28.12 7 94 0.5 60 63.27 320 29.52 6 93 PICTURE (CONTINUED) Example Rubber Catalyst Hardness UTS Alarming My TS OS (ppm Pt) (A) (kg / cm2 (%) (kg / cm2 (%) (%))) 7 G 0.25 56 60.45 400 32.33 9 119 0.5 56 68.19 330 30.93 8 92 1 63 64.67 270 31.63 6.5 85 8 H 0.25 58 50.75 255 28.75 9.5 133 0.35 60 58.34 259 32.54 7.5 118 0.5 60 54.76 236 30.65 7.5 108 1 63 60.03 207 35.36 7 91 9 I 0.25 53 44.57 406 22.35 105 185 0.35 56 51.24 390 24.74 9 165 0.5 58 54.34 321 27.69 8.5 123 1 60 56.38 241 30.58 8 101 J 0.25 57 60.45 400 30.22 7 110 0.35 58 59.75 280 30.22 7 97 1 59 54.83 210 31.63 5 93 11 K 0.25 55 46.25 342 22.28 10 159 0.35 57 59.54 393 23.05 9.5 127 0.5 59 62.77 346 27.97 7.5 108 1 61 68.40 267 32.83 6.5 92 12 L 0.25 52 34.79 236 20.17 9.5 164 0.35 53 41.82 254 22.49 9.5 164 0.5 56 43.65 241 23.19 8.5 137 1 58 56.02 237 28.61 8 111 13 M 0.25 53 37.39 305 20.45 10.5 162 0.35 54 46.32 297 24.46 9.5 145 0.5 56 48.71 282 25.66 8.5 129 1 60 56.38 253 28.82 7.5 104 Examples 1-4 are outside the scope of the invention. In such examples any Mooney viscosity (MST) was found below the critical level (examples 2-4) or the diene content of the elastomeric polymer was found below the critical level (example 1). In those four examples, the physical properties of the thermoplastic elastomer were inferior to the physical properties of the compositions within the scope of the invention. The tensile strength of the products was low and the oil increase was high, indicating a low degree of interlacing of the rubber component. In contrast, examples within the scope of the invention (examples 5-13) demonstrated that the use of a rubber component containing approximately 0.3 weight percent or more of vinyl norbonne and having a Mooney viscosity on the scale of MST of about 45 to about 100 produces a thermoplastic elastomer product having an unexpectedly improved combination of physical properties. Said improvement was achieved even at extremely low concentrations of hydrosilylation catalyst. Although the best mode and preferred embodiment of the invention have been described in accordance with the patent statutes, the scope of the invention is not limited thereto, but in turn is defined by the appended claims.

Claims (15)

NOVELTY OF THE INVENTION CLAIMS

1. - In a process for the dynamic vulcanization of an unsaturated rubber in a mixture with a thermoplastic resin in the presence of a hydrosilylation agent and hydrosilylation catalyst, the improvement comprising the use as well as the rubber of ethylene, α-olefin as non-conjugated elastomeric polymer, characterized in that said elastomeric polymer contains from about 40 to about 90 weight percent ethylene and about 0.25 weight percent or more vinyl norbornene, with a Mooney viscosity in the MST scale of about 45. to about 100.

2. The process according to claim 1, further characterized in that said elastomeric polymer has a branching index of about 0.1 to about 1.0.

3. The process according to claim 1, further characterized in that said elastomeric polymer contains from about 50 to about 75 weight percent of ethylene and from about 0.5 to about 1.2 weight percent of vinyl norbornene.

4. The process according to claim 1, further characterized in that said elastomeric polymer has a Mooney viscosity on the MST scale of about 50 to about 85 and a branching index of about 0.5 to about 1.0.

5. The method according to claim 1, further characterized in that the thermoplastic resin is polypropylene and the unsaturated rubber is rubber of EPDM.

6. The process according to claim 1, further characterized in that the unsaturated rubber is completely entangled by dynamic vulcanization.

7. The process according to claim 1, further characterized in that the dynamic vulcanization is carried out in the presence of the processing or oil to spread the rubber which is substantially free of materials having the chemical behavior and a Lewis base.

8. A thermoplastic elastomer prepared by the process according to claim 1. 9.- In the thermoplastic elastomer composition comprising the mixture of thermoplastic resin and a unsaturated rubber that has been crosslinked by dynamic vulcanization using a hydrosilylation agent and a hydrosilylation catalyst, in the improvement comprising said rubber is an ethylene, α-olefin, non-conjugated diene elastomeric polymer further characterized in that said elastomeric polymer contains from about 40 about 90 weight percent ethylene and from about 0.25 weight percent. by weight or more of vinyl norbornene, with a Mooney viscosity on the MST scale of about 45 to about 100. 10. The composition according to claim 9, further characterized in that said elastomeric polymer has a branching index of about 0.1 to approximately 1.0. 11. The composition according to claim 9, further characterized in that said elastomeric polymer contains from about 50 about 75 weight percent ethylene and from about 0.5 about 1.2 weight percent vinyl norbornene. 12. The composition according to claim 9, further characterized in that said elastomeric polymer has a Mooney viscosity on the MST scale of about 50 to about 85 and a branching index of about 0.5 about 1.0. 13. The composition according to claim 9, further characterized in that the thermoplastic resin is polypropylene and the unsaturated rubber is rubber of EPDM. 14. The composition according to claim 9, further characterized in that the unsaturated rubber is completely crosslinked by dynamic vulcanization. < 15. The composition according to claim 9, further characterized in that the dynamic vulcanization is carried out in the presence of the processing or oil to spread the rubber which is substantially free of materials having the chemical behavior of a base of Lewis.