WO2007082571A1

WO2007082571A1 - Thermoplastic polyolefins and methods for their production

Info

Publication number: WO2007082571A1
Application number: PCT/EP2006/011495
Authority: WO
Inventors: Trazollah Ouhadi
Original assignee: Exxonmobil Chemical Patents Inc.
Priority date: 2006-01-20
Filing date: 2006-11-30
Publication date: 2007-07-26
Also published as: GB0601166D0

Abstract

The invention relates to a soft TPO composition that may be used for making soft touch overmolding, which composition comprises a) a crystalline polypropylene component having a heat of fusion of at least 70 J/g in an amount of from 5 to 50 wt%; b) a propylene based elastomer having a heat of fusion of from 5 to 60 J/g and a triad tacticity of from 5 to 60 wt%; c) a thermoplastic elastomer in an amount of from 5 to 50 wt% having no propylene type crystallinity suitable for absorbing processing oil; and d) an extender oil predominantly absorbed by said component c) in an amount of 5 to 50 wt%; e) from 0 to 40 wt% of a filler; all percentages being based on the combined weight of a) to e) and the total weight of a) to e) amounting to from 90 to 100 % of the total composition weight.

Description

THERMOPLASTIC POLYOLEFINS AND METHODS FOR THEIR

PRODUCTION

FIELD OF INVENTION [0001] The invention relates to thermoplastic polyolefins (TPO) comprising a thermoplastic crystalline polypropylene, a propylene based elastomer, a thermoplastic elastomer, and, process oil. The TPO typically is soft and flexible and may have low to no tendency for oil exudation.

BACKGROUND OF THE INVENTION

[0002] TPO's containing propylene based elastomer are described in:

a) WO200069965- US6750284- EPl 189986: The TPO is used for a membrane of from 1-40 wt% crystalline polypropylene and a propylene based elastomer containing from 80 to 93 wt% of propylene derived units. . From 1 to 40 wt% of filler and from 1 to 25 wt% of processing oil may also be present;

b) US6245856-EP946640: The TPO comprises from 88-50 wt% of polypropylene, less than 10 wt% of an ethylene-propylene copolymer (EP copolymer) or terpolymer (EPDM) and from 2- 15 wt% of the propylene based elastomer;

c) WO2004035681- US2005-0054781- EP1554344 discloses a TPO composition broadly with inclusion of a higher density polyethylene derived component.

d) Unpublished art includes US2006/0235159 filed on 14 April 2005 and published after the priority date which discloses blends of propylene based elastomer and isotactic polypropylene with processing oil and a hydrocarbon resin. There is no disclosure of the use of a thermoplastic elastomer having no isotactic polypropylene type crystallinity suitable for absorbing oil or filler. USSN 60/671219 particularly describes a composition comprising a first polymer component comprising propylene, with an MFR @ 230⁰C > about 25 g/10 min. and a melting temperature of > about HO⁰C; and a second polymer component comprising propylene having a heat of fusion < 75 J/g and a triad tacticity of from about 50% to about 99%, the SPC having an MFR @ 230⁰C < about 800 g/10 min.; and a hydrocarbon resin.

e) US2006/0135699 filed on 29 April 2005 is published after the priority date of this application. This teaches blending a poly-alpha-olefin oil or plasticizer with a propylene based elastomer to form a blend. In particular a semi-crystalline polymer may comprises 68 to 92 mol% of propylene, and 8 to 32 mol% of ethylene, or a C₄- C₂₀ olefin and the plasticizer may comprise a poly-alpha olefin comprising linear alpha olefins having 5 to 14 carbon atoms.

[0003] WO-A-98127154 describes dynamically vulcanized compositions often designated as a thermoplastic vulcanizate or TPV comprising conventional propylene polymer, an EP or EPDM elastomer and a propylene based elastomer as compatibilizer. In WO-A-98127155 a blend of EPDM, PP and metallocene-PP is vulcanized. EP794226 describes blends of two different polypropylenes and elastomer in which a compatibilizing polypropylene is made by metallocene catalysts.

[0004] US6288171-EP969043 describes a thermoplastic composition in which certain amounts of crystalline polypropylene are mixed with larger amounts of a propylene based elastomer with varying oil contents.

[0005] The Shore A or D hardness of a TPO can be reduced by adding oil which also aids the processability in molding applications. However excessive oil levels can lead to oil exudation. Depending on the selection of polymers the composition can have a greater or reduced ability to absorb oil with acceptable exudation levels. SUMMARY OF THE INVENTION

[0006] The essential, preferred and optional features of the invention are set out in the claims. Accordingly in one aspect the invention provides a TPO composition comprising: a) a crystalline polypropylene component having a heat of fusion of at least 70 J/g in an amount of from 5 to 50 wt%; b) a propylene based elastomer having a heat of fusion of from 5 to 60 J/g and a triad tacticity of from 5 to 60 wt%; c) an elastomer in an amount of from 5 to 50 wt% having no propylene type crystallinity suitable for absorbing processing oil; d) an extender oil predominantly absorbed by said component c) in an amount of 5 to 50 wt%; and e) from 0 to 40 wt% of a filler; all percentages being based on the combined weight of a) to e) and the total weight of a) to e) amounting to from 80 to 100 % of the total composition weight. Other additives, discussed below may make up the balance of the composition.

[0007] As defined in this specification and claims, the amounts specified of the different ingredients a) to e) represent the sum of those ingredients in the final blend resulting from the contribution of one or more pure or premixed components. For example the elastomer c) may be added as part of a TPV composition containing largely component c) (and then represents the rubber phase contained within a polypropylene matrix) and possibly some of d) but also some of the isotactic polypropylene component a). Similarly the propylene based elastomer b) may be supplied to the mixing process as a blend containing a small amount of isotactic polypropylene that will count towards calculating the amount of polypropylene component a) to provide pellet stability.

The elastomer component c) combines with the elastomer component b) to restrain oil exudation while permitting the presence of a sufficient amount of the polypropylene component a) and propylene based elastomer component b) to provide the desired overall processability and final properties for the articles manufactured from the composition.

DETAILED DESCRIPTION OF PROPYLENE BASED ELASTOMER [0008] The propylene based elastomer has isotactic triad tacticity indicating a sufficient presence of stereoregular inserted propylene derived units. The triads and sequences with more than three propylene derived units in stereoregular form contribute to the heat of fusion, which reflects the formation of crystallites from stereoregular propylene based sequences. The total crystallinity provided by the propylene based elastomer and any polymeric adjuvant influences the flexibility of the cured article. The crystallinity of the propylene based elastomer is selected to provide an overall composition having the desired cured flexibility. If the heat of fusion exceeds 70 J/g the article tends to be too stiff.

[0009] The isotactic triad tacticity of the propylene elastomer ranges from 50 to 99%. As defined herein this percentage is based on the total amount of propylene based triads of all steric configurations in the polymer and ignores the presence of units derived from monomers other than propylene. If the triad tacticity is less than 50%, the effect of the isotactic triad tacticity is outweighed by the influence of other triads and the propylene based elastomer may not have the desired strength- elongation behavior. There may be insufficient potential for the progressive crystallization of the polymer. If the triad tacticity exceeds 99 wt% and the heat of fusion is less than 70 J/g, the polymer contains high levels of units derived from comonomers other than propylene and the desired elastomer behavior cannot be achieved.

[0010] The propylene based elastomer may optionally contain a diene. The diene may be used to intensify the curing step by speeding it or achieving a higher final cure state in the case of curatives such as peroxide containing curatives. Peroxide containing curatives can also function to effect crosslinking without diene derived unsaturation being present in the propylene based elastomer. In this case the propylene based elastomer should have a molecular weight, usually expressed in units Mooney or Melt Flow rate (MFR), which is sufficient to withstand any scissioning of the polymer chain that may occur during curing, and to provide, together with other components of the composition, a viscosity appropriate to the chosen shaping technique.

[0011] Propylene elastomers not containing dienes are preferred. The absence of diene residues in the polymer aids the thermal stability. The peroxide cure system permits curing in the absence of diene derived units in the polymer. If dienes are present, the elastomer may contain from 0.1 to 8 wt% of diene derived comonomer units for promoting curing. The cure state as determined by ODR @ 170⁰C, 30 min MH-ML may be from 20 to 50 dNm. The amount of the polyene present in the polymeric components can be inferred by the quantitative measure of the amount of the pendent free olefin present in the polymer after polymerization. Several procedures such as iodine number and the determination of the olefin content by ¹H or C NMR have been established, hi the particular case where the polyene is ENB the amount of polyene present in the polymers can be measured using ASTM D6047. The amount of polyene present is expressed on the basis of the total weight of (for example) ethylene and propylene derived units. In the case of VNB the amount can be determined by the same procedure outline in ASTM D6047 with the difference being instead of measuring the absorbance peak associated with ENB at 1685-1690 cm^"1 the absorbance peak at 1635-1640 cm^'1 assigned to VNB is used. If the propylene elastomer contains substantially no unsaturated moieties, the cure state may be preferably from 20 to 50 dNm. Following cross-linking by whatever means, the cure state as determined by ODR @ 170⁰C, 30 min MH-ML may be from 20 to 50 dNm. [0012] The propylene based elastomer may be selected from any elastomer meeting the requirements of low heat of fusion and high triad tacticity. The propylene based elastomeric polymers are generally produced by random polymerization processes leading to polymers having randomly distributed irregularities in stereoregular propylene propagation. This is in contrast to block copolymers in which constituent parts of the same polymer chains are separately and sequentially polymerized. The term "elastomeric polymer" indicates that the heat of fusion of the polymer as determined by DSC is less than 70 J/g. Generally then the peak melting point as determined by DSC will be below 105⁰C but the elastomers may contain a portion which provide a higher melting point fraction. This is in contrast to propylene copolymers or atactic polymers containing propylene derived units, which lack recovery from elastic deformation.

[0013] The polymer is "propylene based" in the sense that the amount of propylene in the polymer is sufficient to allow stereoregular propylene sequences to crystallize and gives rise to a detectable heat of fusion. This is in contrast with known elastomeric polymers based on ethylene and propylene in which the heat of fusion can be attributed to ethylene derived polymer sequences. Preferably the polymers contain isotactic propylene sequences, separated by stereo or regio error or by one or more units from a comonomer.

[0014] The polymers and compositions described herein can be characterized in terms of their melting points (Tm) and heats of fusion, which properties can be influenced by the presence of comonomers or steric irregularities that hinder the formation of crystallites by the polymer chains. The heat of fusion preferably ranges from a lower limit of 1.0 J/g, or 1.5 J/g, or 3.0 J/g, or 4.0 J/g, or 6.0 J/g, or 7.0 J/g, to an upper limit of 30 J/g, or 40 J/g, or 50 J/g, or 60 J/g. Here and every where else any lower range end may be combined with an upper range end to provide alternative ranges. If the heat of fusion is too high, the polymer may not extend elastically under a sufficiently low force for elastic deformation and have insufficient elastic elongation. If the heat of fusion is too low the polymer may not show a sufficient return force after elastic deformation. The heat of fusion can be reduced by using additional comonomer, higher polymerization temperatures and/or a different catalyst providing reduced levels of steric constraints and favoring more propagation errors for propylene insertion. The melting point of the propylene-based elastomer is preferably <105°C, more preferably <100°C, more preferably <90°C, and in some embodiments <80°C or <75°C. The properties can be determined by Differential Scanning Calorimetry (DSC), using the ASTM E-794-95 (version E-794-01) procedure.

[0015] The term "tacticity" refers to the stereoregularity of the orientation of the methyl residues from propylene in a polymer. The term "isotactic" as in isotactic polypropylene is defined herein as a polymer sequence in which greater than 50% of the pairs of pendant methyl groups located on adjacent propylene units, which are inserted into the chain in a regio regular 1,2 fashion and are not part of the backbone structure, are located either above or below the atoms in the backbone chain, when such atoms in the backbone chain are all in one plane. Pairs of methyl residues from contiguous propylene units identically inserted which have the same orientation with respect to the polymer backbone are termed "meso" (m). Those of opposite configuration are termed "racemic" (r). When three adjacent propylene groups have methyl groups with the same orientation, the tacticity of the triad is 'mm'. If two adjacent monomers in a three-monomer sequence have the same orientation, and that orientation is different from the relative configuration of the third unit, the tacticity of the triad is 'rnr'. When the middle monomer unit has an opposite configuration from either neighbor, the triad has 'rr' tacticity. The fraction of each type of triad in the polymer can be determined and, when multiplied by 100, indicates the percentage of that type found in the polymer and is referred to herein as the triad tacticity. The "triad tacticity" of the polymers described herein can be determined from a ¹³C nuclear magnetic resonance (NMR) spectrum of the polymer as described in U.S. Patent No. 5,504,172, and U.S. Patent No. 6,642,316, column 6, lines 38 through column 9, line 18, which patents are hereby incorporated by reference in their entirety. The propylene based elastomer suitably has an isotactic triad fraction of 65 % to 99 % and more especially of 70 % to 98 %. The propylene based elastomer may have an isotactic triad fraction of 75 % to 97%.

[0016] The propylene based elastomer also has tacticity index, expressed herein as "m/r", is determined by ¹³C nuclear magnetic resonance (NMR). The tacticity index m/r is calculated as defined in H.N. Cheng, Macromolecules, 17, 1950 (1984). An m/r ratio of 1.0 generally describes a syndiotactic polymer, and an m/r ratio of 2.0 generally describes an atactic material. An isotactic material theoretically may have a ratio approaching infinity, and many by-product atactic polymers have sufficient isotactic content to result in ratios of greater than 50. The tacticity index reflects the stereoregularity in the polymer.

[0017] The triad tacticity and tacticity index may be controlled by the catalyst influencing the stereoregularity of propylene placement, the polymerization temperature according to which stereoregularity can be reduced by increasing the temperature and by the type and amount of a comonomer which tends to disrupt reduce the level of longer propylene derived sequences as described in more detail in WO2005/49670. Preferably the polymer contains at least some comonomer, such as an alpha-olefin, in order to facilitate control of the structure. Preferably the comonomer comprises substantially ethylene which can aid in achieving economic polymerization conditions by raising the molecular weight and/or permitting a higher polymerization temperature.

[0018] The propylene based elastomer described herein is a polymer of propyl ene- derived units and optionally one or more units derived from a C2 or C4-C20 α-olefin. Generally the amount of the ethylene or alpha-olefin combined varies from 5 to 35 mol %, preferably from 10 to 25 weight percent and especially from 12 to 20 wt%. Preferred α-olefins are ethylene, butene, hexene and octene or combinations thereof as the propylene-based elastomer may contain more than more α -olefin. The total weight percent of the C2 or C4-C20 α-olefin-derived units is preferably from about 5 wt% to about 35 wt%, more preferably from about 7 wt% to about 32 wt%, more preferably from about 8 wt% to about 25 wt%, more preferably from about 8 wt% to about 20 wt%, and more preferably from about 8 wt% to about 16 wt%. Particular embodiments of polymers having more than one α-olefin include propyl ene-ethylene- octene, propylene-ethylene-hexene and propyl ene-ethylene-butene polymers. In some embodiments, where more than one comonomer is present, the amount of a particular α-olefin comonomer may be < 5 wt%, but the combined α-olefin comonomer content is preferably > 5 wt%. Where ethylene forms the principal or only comonomer, generally the amount of the ethylene or α-olefin combined varies from 5 to 35 mol %, preferably from 8 to 25 weight percent, more preferably 10 to 20 wt%. Too much comonomer will reduce the crystallinity provided by the crystallization of stereoregular propylene derived sequences to the point where the material lacks elastic recovery; too little and the material will be too crystalline, have a high melting point and be insufficiently elastic.

[0019] The comonomer content and sequence distribution of the polymers can be measured using ¹³C nuclear magnetic resonance (NMR) by methods well known to those skilled in the art and as described in detail in WO2005/49670 incorporated herein by reference for US purposes.

[0020] The propylene based elastomers may be prepared using process and catalyst options as set out in WO2005/49670. The active transition metal complex is preferably of a single site type, including metallocene or heteroligand (pyridinal) based options. The crystallinity of the propylene-based elastomer can be reduced also by stereo-irregular incorporation of the propylene-derived units, which can be influenced by, for example, the choice of catalyst and polymerization temperature. The low crystallinity polymers can be made by the continuous solution polymerization process described in W02002/34795 incorporated herein by reference for US purposes or US 2002004575 incorporated herein by reference for US purposes, optionally in a single reactor and separated by liquid phase separation from the alkane solvent. The low crystallinity polymers of the present invention can be produced in the presence of a chiral metallocene catalyst with an activator and optional scavenger. The use of single site catalysts can be used to enhance the homogeneity of the low crystallinity polymer. As only a limited tacticity is needed many different forms of single site catalyst may be used. Possible single site catalysts are metallocenes, such as those described in U.S. Patent No. 5,026,798 incorporated herein by reference for US purposes, which have a single cyclopentadienyl ring, optionally substituted and/or forming part of a polycyclic structure, and a hetero- atom, generally a nitrogen atom, but possibly also a phosphorus atom or phenoxy group connected to a group 4 transition metal, such as titanium, zirconium, or hafnium. A further example is Me5CpTiMe3 activated with B(CF)3 as used to produce elastomeric polypropylene with an Mn of up to 4 million. See Sassmannshausen, Bochrnann, Rosch, Lilge, J, Organornet. Chem. (1997), vol548, pp. 23-28. Other possible single site catalysts are metallocenes which are bis cyclopentadienyl derivatives having a group transition metal, such as hafnium or zirconium. Such metallocenes may be unbridged as in U.S. Patent No. 4,522,982 incorporated herein by reference for US purposes or U.S. Patent No. 5,747,621 incorporated herein by reference for US purposes. The metallocene may be adapted for producing the low crystallinity polymer comprising predominantly propylene derived units as in U.S. Patent No. 5,969,070 incorporated herein by reference for US purposes which uses an unbridged bis-(2 -phenyl indenyl) zirconium dichloride to produce a homogeneous polymer having a melting point of above 79°C. The cyclopentadienyl rings may be substituted and/or part of polycyclic systems as described in the above U.S. Patents. Other possible metallocenes include those in which the two cyclop entadienyls are connected through a bridge, generally a single atom bridge such as a silicon or carbon atom with a choice of groups to occupy the two remaining valencies. Such metallocenes are described in U.S. Patent No. 6,048,950 which discloses bis(indenyl)bis(dimethylsilyl) zirconium dichloride and MAO; WO 98127154 incorporated herein by reference for US purposes which discloses a dimethylsilyl bridged bis-indenyl hafnium dimethyl together with a non- coordinating anion activator; EP 1070087 which discloses a bridged biscyclopentadienyl catalyst which has elements of asymmetry between the two cyclopentadienyl ligands to give a polymer with elastic properties; and the metallocenes described in U.S. Patent Nos. 6,448,358 incorporated herein by reference for US purposes and 6,265,212 incorporated herein by reference for US purposes. Pyridine amide based single site catalysts are described in WO2003/040201 incorporated herein by reference for US purposes.

[0021] The manner of activation of the single site catalyst can vary. Alumoxane, such as methyl alumoxane, may be used. Higher molecular weights may be obtained using non-or weakly coordinating anion activators NCA) derived and generated in any of the ways amply described in published patent art such as EP277004, EP426637 both incorporated herein by reference for US purposes, and many others. Activation generally is believed to involve abstraction of an anionic group such as the methyl group to form a metallocene cation, although according to some literature zwitterions may be produced. The NCA precursor may be an ion pair of a borate or aluminate in which the precursor cation is eliminated upon activation in some manner, e.g. trityl or ammonium derivatives of tetrakis pentafluorophenyl boron (See EP277004). The NCA precursor may be a neutral compound such as a borane, which is formed into a cation by the abstraction of and incorporation of the anionic group abstracted from the metallocene (See EP426638 incorporated herein by reference for US purposes). In a particular embodiment, the catalyst system used to produce the propylene-based elastomer includes one or more transition metal compounds and one or more activators. When alumoxane or aluminum alkyl activators are used, the combined pre-catalyst-to-activator molar ratio is generally from 1:5000 to 10: 1. When ionizing activators are used, the combined pre-catalyst-to-activator molar ratio is generally from 10:1 to 1 :10. Multiple activators may be used, including using mixtures of alumoxanes or aluminum alkyls with ionizing activators. In another embodiment, the propylene-based elastomer is made in the presence of an activating cocatalyst which is a precursor ionic compound comprising a halogenated tetra-aryl- substituted Group 13 anion wherein each aryl substituent contains at least two cyclic aromatic rings, hi a particular aspect of this embodiment, the propylene-based elastomer contains greater than 0.2 parts per million, or greater than 0.5 parts per million, or greater than 1 part per million, or greater than 5 parts per million of the residues of the activating cocatalyst. For example the catalyst system used to produce the propylene-based elastomer may be Hf-containing metallocene catalyst, such as but not limited to dimethyl silyl bis(indenyl) hafnium dimethyl, and a non- coordinating anion activator, such as but not limited to dimethyl anilinium tetrakis(heptafluoronaphthyl) borate.

[0022] The propylene based elastomer may possess varying molecular weight distributions and degrees of long chain branching which influence the melt processability and can be selected together with reinforcing filler content, processing oil etc. to provide the desired processability prior to curing.

[0023] In a random propylene copolymer as described above the number and distribution of ethylene residues may be consistent with the statistical polymerization of ethylene, propylene and optional amounts of diene. In stereoblock structures, the number of monomer residues of any one kind adjacent to one another is greater than predicted from a statistical distribution in random propylene copolymers with a similar composition. Such random distributions are in contrast with stereoblock structures.

DETAILED DESCRIPTION OF CRYSTALLINE POLYPROPYLENE [0024] The crystalline polypropylene is defined herein as a polypropylene material having a heat of fusion of at least 70 J/g. It may be made by a conventional or by a single sited catalyst such as a metallocene based catalyst system. The polypropylene may be a homopolymer, a random copolymer having a melting point between 115 ⁰C and 166 ⁰C or an impact copolymer containing a mixture of a high crystallinity polypropylene material with a less crystalline EP material. The polypropylene may be linear or branched.

[0025] Preferably the polypropylene is present in an amount of from 7 to 35 wt%; more preferably from 9 wt% to 20 wt%. Suitably the crystalline polypropylene generally has an MFR of from 5 to 6000, preferably from 100 to 5000, and more preferably 500 to 3000 dl/minute. The high MFR helps, possibly in conjunction with the processing oil, to provide a high flow thermoplastic elastomer blend for easy processability especially in injection molding.

DETAILED DESCRIPTION OF OIL ABSORBING ELASTOMER

[0026] The oil absorbing elastomer component c) may be at least partly provided by i) an at least partially crosslinked thermoplastic vulcanizate (TPV); or ii) a non-cross- linked styrenic block copolymer or a combination of these. A TPV contains PP or other semi-crystalline polyolefin as thermoplastic phase and an at least partially cross-linked elastomer phase dispersed through the semi-crystalline phase. The elastomeric phase preferably has substantial absence of crystallinity to permit the effective absorption of the oil. Suitably then the elastomer has a heat of fusion of no more than 5 J/g, preferably no more than 2 5 J/g. The elastomer may devoid of any measurable crystallinity. The ability to absorb oil can be increased by reducing the crystallinity and providing that, if crystallinity is present, that crystallinity is not generated by isotactic propylene derived sequences as is the case for component b).

[0027a] The elastomer phase of the TPV is imported together with a crystalline phase, which may be polypropylene and which may then contribute towards to the total amount of component a) of the invention as set out in Claim 1. The elastomer may be an ethylene based elastomer such as an ethylene based copolymer (not containing diene) or a non-conjugated diene containing polymer such as an EPDM. Other options for component c) include chloroprene, acrylonitrile rubber or acrylic rubber. Other options are non- or partially hydrogenated styrene-conjugated block copolymers with substantial absence of crystallinity such as a styrene butadiene styrene (SBS), styrene isoprene styrene (SIS) or styrene ethylene butadiene styrene (SEBS) or styrene ethylene propylene styrene (SEPS) block copolymers. These styrenic block copolymer may be as pure polymer or as a blend with PP, process oil or mineral filler .hi case of a blend, the styrenic block copolymer may be partially or fully cross-linked. All of the aforementioned may be at least partially crosslinked by a suitable cross-linking package as are well known in the TPV art to a person skilled in the art. Suitable options are described in WO02/059194 incorporated herein by reference for US purposes. EPDM-type rubbers are generally terpolymers derived from the polymerization of at least two different mono-olefin monomers having from 2 to 10 carbon atoms, preferably 2 to 4 carbon atoms, and at least one polyunsaturated olefin having from 5 to 20 carbon atoms. Said mono-olefins desirably have the formula CH2=CH-R where R is H or an alkyl of 1-12 carbon atoms and are preferably ethylene and propylene. Desirably the repeat units from at least two mono- olefins (and preferably from ethylene and propylene) are present in the polymer in weight ratios of 25:75 to 75:25 (ethylene:propylene) and constitute from about 88 to about 99.6 weight percent of the polymer. The polyunsaturated olefin can be a straight chained, branched, cyclic, bridged ring, bicyclic, fused ring bicyclic compound, etc., and preferably is a non-conjugated diene. Desirably repeat units from the non-conjugated polyunsaturated olefin comprise from 0.4 to 12 weight percent of the rubber.

[0027b] The elastomer c ) may also comprise a butyl rubber, halobutyl rubber, or a halogenated (e.g. brominated) copolymer of p-alkylstyrene and an iso-mono-olefin of 4 to 7 carbon atoms. "Butyl rubber" is defined a polymer predominantly comprised of repeat units from isobutylene but including a few repeat units of a monomer which provides sites for crosslinking. The monomers which provide sites for crosslinking can be a polyunsaturated monomer such as a conjugated diene or divinyl benzene. Desirably from 90 to 99.5 weight percent of the butyl rubber are repeat units derived from the polymerization of isobutylene and from 0.5 to 10 weight percent of the repeat units are from at least one polyunsaturated monomer having from 4 to 12 carbon atoms. Preferably the polyunsaturated monomer is isoprene or divinyl benzene. The polymer may be halogenated to further enhance reactivity in crosslinking. Preferably the halogen is present in amounts from 0.1 to 10 weight percent, more preferably 0.5 to 3.0 weight percent based upon the weight of the halogenated polymer; preferably the halogen is chlorine or bromine. The brominated copolymer of p-alkylstyrene, having from 9 to 12 carbon atoms, and an iso-mono- olefin, having from 4 to 7 carbon atoms, desirably has from 88 to 99 weight percent iso-mono-olefin, more desirably from 92 to 98 weight percent, and from 1 to 12 weight percent p-alkyl styrene, more desirably from 2 to 8 weight percent based upon the weight of the copolymer before halogenation. Desirably the alkylstyrene is p- methylstyrene and the iso mono-olefin is isobutylene. Desirably the percent bromine is from 0.2 to 8, more desirably from 0.2 to 3 weight percent based on the weight of the halogenated copolymer. These polymers are commercially available from ExxonMobil Chemical Company.

[0027c] Other rubbers such as natural rubber or synthetic homo or copolymers from at least one conjugated diene can be used in the TPV dynamic vulcanizate. These rubbers are higher in unsaturation than EPDM rubber and butyl rubber. The natural rubber and said homo or copolymers of a diene can optionally be partially hydrogenated to increase thermal and oxidative stability. The synthetic rubber can be non-polar or polar depending on the comonomers. Desirably the homo or copolymers of a diene have at least 50 weight percent repeat units from at least one conjugated diene monomer having from 4 to 8 carbon atoms. Comonomers may be used and include vinyl aromatic monomer(s) having from 8 to 12 carbon atoms and acrylonitrile or alkyl-substituted acrylonitrile monomer(s) having from 3 to 8 carbon atoms. Other comonomers desirably used include repeat units from monomers having unsaturated carboxylic acids, unsaturated dicarboxylic acids, unsaturated anhydrides of dicarboxylic acids, and include divinyl benzene, alkylacrylates and other monomers having from 3 to 20 carbon atoms. Examples of synthetic rubbers include synthetic poly-isoprene, polybutadiene rubber, styrene-butadiene rubber, butadiene- acrylonitrile rubber, etc. Amine-functionalized, carboxy-functionalized or epoxy- functionalized synthetic rubbers may be used, and examples of these include maleated EPDM, and epoxy-functionalized natural rubbers. These materials are commercially available.

[0027d] The elastomer component c) may also include a non-cross-linked elastomer for absorbing the processing oil. For example a non or partially hydrogenated styrene-conjugated block copolymers with substantial absence of crystallinity such as an SBS, SIS or SEBS, SEPS block copolymer may be used. These may be used pure or in blends with more crystalline polymers containing other additives.

[0027e] The precise nature of the elastomer component c) and the nature of the process oil may be selected relative to the propylene based elastomer component b) so as to ensure that component c) absorbs process oil in preference to component b). Preferably therefore the component c) has a heat of fusion as determined by DSC that is less more than 2 J/g, more preferably more than 5 J/g or even more than 10 or 20 J/g less than that of the propylene based elastomer b). Similarly the amount of component c) may be adjusted so that the total oil absorbing capacity is such that the process oil d) added does not overload the oil absorbing capacity of the propylene based elastomer component b). Within such constraints and with appropriate selection of non-reinforcing fillers and other optional components, soft, flexible compositions may be produced.

DETAILED DESCRIPTION OF PROCESS OIL

[0028] The process oil may be a paraffinic, naphthenic oil or synthetic oil. The addition of process oil may lower the viscosity and increase flexibility of the blend while improving the properties of the blend at temperatures near and below 0°C. It is believed that these benefits arise by the lowering of the Tg of the blend. Additional benefits of may include improved processability and a better balance of elastic and tensile strength.

[0029] The oil may be predominantly absorbed by said component c) and is preferably used in an amount of in an amount of 10 to 35 wt%, most preferably in amount of 15 to 30 wt%. As indicated in paragraph [0007] the total amount of oil may be derived from a combination of starting components containing oil such as the thermoplastic elastomer c), and additional oil, generally referred to as free oil.

[0030] The oil may be a synthetic poly-alpha-olefinic (PAO) oil with a viscosity of from 5 to 500 Centistoke at 40 C as described for example in in WO2004/14988. The polyalphaolefin (PAO) may be a liquid with a number-average carbon number of 20 to 1500, preferably 35 to 400, preferably 40 to 250. The PAO may comprise oligomers of C5 to C24 (preferably C6 to C18, preferably C6 to C14, preferably C8 to C 12) alpha-olefϊns. In a preferred embodiment, the PAO comprises C5 to C24 (preferably C6 to C18, preferably C6 to C14, preferably C8 to C12, preferably ClO) linear alpha-olefins. Particularly preferred are oligomers of 1-octene, 1-decene, and/or 1-dodecene. Most preferred are oligomers of 1-decene.

[0031] The PAO may comprise oligomers of a single alpha-olefin having 5 to 24 (preferably 6 to 18, preferably 8 to 12, preferably 10) carbons. In another embodiment, the NFP comprises oligomers of mixed alpha-olefins (i.e., involving two or more alpha-olefins), each alpha-olefin having 3 to 24 (preferably 5 to 24, preferably 6 to 18, preferably 8 to 12) carbons. The PAO may comprise oligomers of mixed alpha-olefins (i.e., involving two or more alpha-olefins) where the weighted average number for all the alpha-olefms is between 6 and 14 (preferably between 8 and 12, preferably between 9 and 11) carbons. The PAO may comprise oligomers of linear alpha-olefins having 5 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, more preferably 10 carbon atoms, with a kinematic viscosity (KV) at 100°C of 3 cSt or more, preferably 6 cSt or more, preferably 8 cSt or more, preferably 10 cSt or more (as measured by ASTM D445); and preferably having a viscosity index (VI) of 100 or more, preferably 110 or more, more preferably 120 or more, more preferably 130 or more, more preferably 140 or more, preferably 150 or more (as determined by ASTM D2270); and preferably having a pour point of -10°C or less, more preferably -2O⁰C or less, more preferably -30°C or less, more preferably -40°C or less, more preferably -50°C or less (as determined by ASTM D97). Preferred PAOs are described more particularly in, for example, US 5,171,908, and US 5,783,531 and in Synthetic Lubricants and High-Performance Functional Fluids 1-52 (Leslie R. Rudnick & Ronald L. Shubkin, ed. Marcel Dekker, Inc. 1999). Desirable PAOs are commercially available as SpectraSyn™ and SpectraSyn Ultra™ from ExxonMobil Chemical in Houston, Texas (previously sold under the SHF and SuperSyn™ tradenames by ExxonMobil Chemical Company). Other useful PAOs include those ^'sold under the tradenames Synfluid™ available from ChevronPhillips Chemical Company (Pasedena, Texas), Durasyn™ available from Innovene (Chicago, Illinois), Nexbase™ available from Neste Oil (Keilaniemi, Finland), and Synton™ available from Chemtura Corporation (Middlebury, Connecticut). Particularly preferred PAOs for use herein are those having a) a flash point of 200⁰C or more (preferably 21O⁰C or more, preferably 220⁰C or more, preferably 23O⁰C or more); and b) a pour point less than -2O⁰C (preferably less than -25°C, preferably less than -30⁰C, preferably less than -35°, preferably less than -40⁰C) or a kinematic viscosity at 100⁰C of 10 cSt or more (preferably 35 cSt or more, preferably 40 cSt or more, preferably 50 cSt or more).

[0032] The process oil may be typically known as extender oil in rubber applications. Process oils also may include plasticizer type components such as hydrocarbons having either (a) traces of hetero atoms such oxygen or (b) at least one hetero atom such as dioctyl phthalate, ethers, and polyethers.

[0033] Process oils are commonly available either as neat solids, liquids, or as physically absorbed mixtures of these materials on an inert support (e.g., clay, silica) to form a free flowing powder. The process oils are suitably be compatible or miscible with the polymer blend composition in the melt.

[0034] The addition of the process oils maybe made by any of the conventional means known to the art. The process oil may be added in the process of finishing the polymer into pellets or bales following polymerization or may be added following finishing in some compounding step. Thus part or all of the process oil may be added prior to recovery of the polymer as well as subsequently, in whole or in part, to the polymer as a part of a compounding step. For example the amorphous component c) and the processing oil may be pre-mixed during a dynamic vulcanization step. The compounding step may be carried out in a batch mixer in a continuous process such as a twin screw extruder. The addition of certain process oils to lower the glass transition temperature of blends of isotactic polypropylene and ethylene propylene diene rubber has been described in the art in US5290886 and US5397832. DETAILED DESCRIPTION OF FILLER

[0035] The filler component may comprise a mineral or inorganic filler such calcium carbonate, clay, silica, talc, mica, wollastonite, barium sulfate or fibers, carbon fibers or nano-clay or a pigment such as carbon black, zinc oxide, titanium dioxide, distributed through a continuous polymer phase. Where available, a calcinated or non-calcinated form may be chosen.

[0036] The amount of inorganic filler used is preferably 5 to 35 wt%, most preferably 10 to 30 wt%. As indicated in paragraph [0007], the filler may be contributed by different starting ingredients. The inorganic fillers may include particles less than 1 mm in diameter, rods less than 1 cm in length, and plates less than 0.2 cm² in surface area, filler is mica. The addition of very small particulate fibers, commonly referred to as nano-composites, is also contemplated. A non-reinforcing filler is preferred, such as calcium carbonate, to preserve the softness and flow properties of the composition that might be reduced by the use of a reinforcing filler such as carbon black. Naturally mixtures of fillers may also be used. The addition of the fillers may thus change the properties of the compositions described herein.

DETAILED DESCRIPTION OF OTHER ADDITIVES

[0037] Optionally other polymers may be added such as functionalized polyolefins including as functional group a carboxylic or anhydride function, an epoxy function or a hydroxyl function or an amine function, for improving such properties as printability and/or adhesion to polar substrates. The addition of process aids, such as a mixture of fatty acid ester, calcium fatty acid soap, or fatty acid amide, optionally bound on a mineral filler, to the compositions described herein may help the mixing of the composition and the injection of the composition into a mold. Anti-blocking agents may be used. Other examples of process aids are low molecular weight polyethylene copolymer wax and paraffin wax. The amount of process aid used may be within the range of from 0.1 to 5 phr. Tack improving additives or adhesion promoters may be added. These include hydrocarbon resins and functionally modified resins including but not limited to Escorez^® and Ricobond^® resins.

[0038] Adding antioxidants, UV stabilizer and/or UV absorber to the compositions described herein may improve the long term aging. Such additives are available commercially. .Examples of antioxidants include, but are not limited to quinolein, e.g., trimethylhydroxyquinolein (TMQ); imidazole, e.g., zinc mercapto toluyl imidazole (ZMTI); and conventional antioxidants, such as hindered phenols, lactones, and phosphites. The amount of antioxidants used may be within the range of from .001 to 5 phr by weight.

DETAILED DESCRIPTION OF BLENDING PROCEDURE

[0039] The compositions can be compounded by any convenient method, such as by blending of the polymer components, oil, filler and any other additives, either directly in an extruder used to make the finished product, or by pre-melt mixing in a separate extruder (for example, a Banbury mixer). Examples of machinery capable of generating the shear and mixing include extruders with kneaders or mixing elements with one or more mixing tips or flights, extruders with one or more screws, extruders of co- or counter-rotating type, Banbury mixer, Farrell Continuous mixer, and the Buss Kneader. The type and intensity of mixing, temperature, and residence time required can be achieved by the choice of one of the above machines in combination with the selection of kneading or mixing elements, screw design, and screw speed (<3000 rpm). The blend may contain additives, which can be introduced into the composition at the same time as the other components or later at down stream in case of using an extruder or Buss kneader or only later in time. Additives may be contained in the thermoplastic composition in an amount of from about 0.1 to about 20 % by weight, preferably less than 15 % by weight or optionally less than 10 % by weight, based on the total weight of the thermoplastic composition. The additives can be added to the blend in pure form or in master-batches together with one or more of polymer components such as components a), b) or c). The process oil can be added in one addition or in multiple additions.

[0040] The blend can either be a physical blend or an in-reactor blend manufactured by in-reactor processes as known to those of ordinary skill in the art. Preferably, the filled thermoplastic olefin composition comprises the filler together with an in-reactor blend of a propylene based copolymer and an isotactic polypropylene. The in-reactor blend preferably is made using a series or parallel solution polymerization process as known to those of ordinary skill in the art.

[0041] The propylene based elastomer b) can be either 1) incorporated into the components used to contribute the thermoplastic elastomer having no propylene type crystallinity, such as a thermoplastic vulcanizate (TPV) and/or the block copolymer compound, or 2) blended with the thermoplastic elastomer having no propylene type crystallinity prior to any vulcanization of the rubber component, or 3) added after any such vulcanization.

[0042] The terms "blend" and "thermoplastic vulcanizate" used herein mean a mixture ranging from small particles of crosslinked rubber well dispersed in a semi- crystalline polypropylene matrix to co-continuous phases of the semicrystalline polypropylene and a partially to fully crosslinked rubber or combinations thereof. The term "thermoplastic vulcanizate" indicates the rubber phase is at least partially vulcanized (crosslinked).

[0043] The thermoplastic elastomers may be prepared by using blending and dynamic vulcanization techniques that are well known in the art. Preferably, the thermoplastic elastomers are prepared in a one-step process whereby the rubber, the LCB-plastic, and the optional linear thermoplastic resin are blended and the rubber is dynamically vulcanized within the blend. The term dynamic vulcanization refers to a vulcanization or curing process for a rubber contained in a thermoplastic elastomer composition, wherein the rubber is vulcanized under conditions of high shear at a temperature above the melting point of the polyolefin component. The rubber is thus simultaneously crosslinked and dispersed as fine particles within the polyolefin matrix, although other morphologies may also exist. Dynamic vulcanization is effected by mixing the thermoplastic elastomer components at elevated temperature in conventional mixing equipment such as roll mills, Banbury mixers, Brabender mixers, continuous mixers, mixing extruders and the like. Those ordinarily skilled in the art will appreciate the appropriate quantities, types of cure systems, and vulcanization conditions required to carry out the vulcanization of the rubber. The rubber can be vulcanized by using varying amounts of curative, varying temperatures, and a varying time of cure in order to obtain the optimum crosslinking desired. The term vulcanized or cured rubber refers to an elastomeric polymer that has undergone at least a partial cure. The degree of cure can be measured by determining the amount of gel, or conversely, the rubber that is extractable from the thermoplastic elastomer by using boiling xylene or cyclohexane as an extractant. This method is disclosed in U.S. Patent No. 4,311,628. By using this method as a basis, the cured rubber of this invention will have a degree of cure where not more than 35 percent of the rubber is extractable, preferably not more than 15 percent, even more preferably not more than 10 percent, and still more preferably not more than 5 percent of the rubber is extractable. Alternatively, the degree of cure may be expressed in terms of crosslink density. Preferably, the crosslink density is from about 40 to about 160 moles per milliliter of lubber. All of these descriptions are well known in the as and described in US5100947 and 5157081 , which are incorporated herein by reference for US purposes. The TPV can be made by dynamic vulcanization using conventional for those rubbers in thermoplastic vulcanizates and are used in conventional amounts. The curatives include, but are not limited to. phenolic resin curatives, sulfur curatives, with or without accelerators, accelerators alone, peroxide curatives, hydrosilation curatives using silicon hydride and platinum or peroxide catalyst, etc.

[0044] The thermoplastic vulcanizate obtained by this process has from about 15 to about 90 percent by weight of the rubber and from about 10 to about 85 percent by weight of a thermoplastic resin, where said resin is (i) an a-olefin polymer, (ii) a copolymer of an a-olefm and an a-a-olefin diene, or (iii) a mixture thereof. By suitable selection of components a) to e) the ingredients to be blended in simple manner, in a particulate or pellet form, with the process oil the only liquid.

[0045] Oil may be used in the preparation of the thermoplastic elastomer having no propylene type crystallinity. Additional free oil may be added as such in the final mixing stages. The amount of oil in the thermoplastic elastomer having no propylene type crystallinity may vary from 0 to 250 phr, preferably from 50 to 200 phr most preferably from 70 to 150 phr by weight based on the content of that aforementioned elastomer. Filler may be present in the thermoplastic elastomer having no propylene type crystallinity. Additional filler may be added as such. The amount of filler in the thermoplastic elastomer having no propylene type crystallinity may vary from 0 to 150 phr based on the content of that aforementioned elastomer.

DETAILS OF PRODUCTS MADE FROM COMPOSITION [0046] The compositions can be processed to fabricate articles by any suitable means known in the art and especially by injection molding, including over-molding on harder polyolefin substrates to provide a soft touch as well compression molding, or extrusion as well as good adhesion. Generally, the highly filled polypropylene compositions of the present invention can be used in flame retardant (FR) and halogen-free flame retardant (HFFR) applications, sound management such as sound deadening applications, gap filler, flooring applications, wire and cable applications, polymer master-batches, roofing membranes, wall coverings, automotive applications, soft grip with high density, articles having a high density to be used water or other polar fluids, and high density films. Likewise, such highly filled polymer compositions can be used as highly filler loaded master-batch, for instance, for pigments. In the latter case the polypropylene functions as a carrier for the pigment.

[0047] The compositions of the present invention exhibit very good mechanical properties such as tensile strength and tear strength while being processable, for instance, by injection molding.

' Perp =Perpendιcular to flow Par = Parallel to flow Sample 2

*Per.=Perpendicular to flow Par.=Parallel to flow

Sam le 3

2mm ISO plaque

* Per.=Perpendicular to flow Par.=Parallel to flow

TPV-I comprises 53 % Vistalon 3666, 13 % clay, 10% polypropylene blend of fractional (0.7 MFR, 60%) and high flow polypropylene (20 MFR, 40%), 20 % free paraffϊnic oil making an overall oil content 43 % ( 142 phr based on the EPDM). All percentages are by weight based on the whole composition.

TPV-2 is substantially the same except that the amount of clay is 7.7 %, the free oil is white paraffmic oil and the EPDM copolymer is Vistalon 7500. The ingredients used in the abve Sample had the following general characteristics and function:

Claims

1. A TPO composition comprising:

a) a crystalline polypropylene component having a heat of fusion of at least 70

J/g in an amount of from 5 to 50 wt%;

b) a propylene based elastomer having a heat of fusion of from 5 to 60 J/g and a triad tacticity of from 5 to 60 wt%;

c) an elastomer in an amount of from 5 to 50 wt% having no propylene type crystallinity suitable for absorbing processing oil; and

d) an extender oil predominantly absorbed by said component c) in an amount of 5 to 50 wt%;

e) from 0 to 40 wt% of a filler;

all percentages being based on the combined weight of a) to e) and the total weight of a) to e) amounting to from 80 to 100 % of the total composition weight.

2. Composition according to Claim lin which the crystalline polypropylene component having a heat of fusion of at least 70 J/g is present in an amount of from 7 to 35 wt%; more preferably from 9 wt% to 20 wt%.

3. A composition according to Claim 1 or Claim 2 in which the crystalline polypropylene has an MFR of from 100 to 5000, preferably 500 to 3000 dl/minute.

4. A composition according to any of the preceding claims in which the propylene based elastomer has a heat of fusion of from 10 to 50 J/g and/or contains from 5 to 25 wt% of ethylene derived units and/or has an MFR of from 0.1 to 20, preferably from 1 to 10 dl/min.

5. A composition according to any of the preceding claims in which the elastomer having no propylene type crystallinity is present in an amount of from 7 to 40 wt%, more preferably from 10 to 30 wt% and forms part of an at least partially cross-linked TPV composition, non-crosslinked TPE composition or a combination thereof.

6. A composition according to any of the preceding claims in which the extender oil predominantly absorbed by said component c) is present in an amount of in an amount of 10 to 35 wt%, more preferably in amount of 15 to 30 wt%.

7. A composition according to any of the preceding claims in which the filler is a non-reinforcing filler present in an amount of from 5 to 30 wt %.

8. A composition according to any of the preceding claims in which the amount of oil in the elastomer having no propylene type crystallinity varies from 0 to 250 phr, preferably from 50 to 200 phr most preferably from 70 to 150 phr by weight based on the content of that aforementioned elastomer.

9. A method for preparing a composition according to any of Claims 1 to 8. which comprises blending a) and b) with a previously prepared vulcanized blend comprising c) and from 10 to 50 wt% of the total amount of oil in the composition.

10. An article manufactured from a composition according to any of claims 1 to 8 in which the composition is used to make an over-molded injection molded article on a polyolefin substrate.