WO2012067609A1

WO2012067609A1 - Thermaoplastic elastomer composition with improved compression set values

Info

Publication number: WO2012067609A1
Application number: PCT/US2010/056915
Authority: WO
Inventors: Mark Govert Kalisvaart; Hendrik De Groot; Freddy Maria Armand Vervoort; Richard Hoff
Original assignee: Kraton Polymers Us, Llc
Priority date: 2010-11-17
Filing date: 2010-11-17
Publication date: 2012-05-24

Abstract

Compounds comprising block copolymers and polyolefin plastomers and elastomers comprising a mixture of a low softening point polyolefin plastomer or elastomer and polypropylene wherein the low softening point polyolefin plastomer or elastomer is a copolymer of ethylene or propylene with one or more alpha-olefins as comonomer and has a Vicat softening point below 100°C, and a density between 850 and 910 g/dm³, show surprisingly good high temperature properties, in particular, when the polyolefin plastomers were added to compounds comprising block copolymers improved compression set values are obtained, particularly in the temperature range of from 85°C to 125°C.

Description

THERMOPLASTIC ELASTOMER COMPOSITION WITH IMPROVED

COMPRESSION SET VALUES

TECHNICAL FIELD

[0001] The present invention relates to a thermoplastic elastomer composition comprising a specific hydrogenated styrenic block copolymer, a polyolefin mixture, processing oil, and optionally filler. The present invention also relates to a production process thereof, and molded articles comprising the thermoplastic elastomer composition. The thermoplastic elastomer (TPE) composition of the present invention has an excellent combination of hardness and compression set properties. It is very particularly suitable in wide-ranging applications that typically require a durometer hardness (ASTM D2240, expressed as Shore A), in the range of 30-90. The TPE composition of the present invention has an excellent combination of hardness and compression set properties at elevated temperatures, in particular at the temperature window of 80 to 125°C.

BACKGROUND ART

[0002] Thermoplastic elastomer compositions for use in automobile parts and such are well known. More recently such TPE compositions based on high molecular weight block copolymers have drawn attention and gained popularity for a wide range of uses. For instance, compositions based on high molecular weight block copolymers are known from the published application JP 2000103934 (MITSUBISHI CHEM CORP).

[0003] JP 2000103934 discloses thermoplastic elastomer compositions comprising three components (i), (ii) and (iii), in which the following characteristics apply. Component (i) is a hydrogenated product of a block copolymer having a weight average molecular weight (hereinafter referred to as "Mw") of 200 to 450 kg/mole where the content of the polymer having an Mw of 400 kg/mole or more in the block copolymer is 5 % by weight or more, the content of the polymer having an Mw of 200 kg/mole or less in the block copolymer is 20 % by weight or less. The block copolymer is represented by the general formulae (1) or (2):

(1) A-(B-A)n

or

(2) (A-B)n

wherein A is a polymer block comprising a monovinyl aromatic hydrocarbon, B is a polymer block comprising a conjugated diene unit and n is an integer of 1 to 5.

Component (ii) is a softener for rubber.

Component (iii) is an olefmic polymer.

The weight ratio of (i)/(ii) is from 20/80 to 80/20 and the amount of (iii) is from 1 to 300 parts by weight based on a total of 100 parts by weight (i) and (ii).

[0004] US 5,272,016 concerns a biaxially oriented heat shrinkable multilayer stretch film useful as a poultry tray over-wrap. The film includes outer layers each comprising a blend of very low density polyethylene (VLDPE), having a density below about 0.914 g/cm3, and an ethylene alpha-olefin plastomer, having a density below about 0.90 g/cm3. US 5,272,016 also provides background information and a detailed description of polyolefin plastomers (POPs) having a Vicat softening point below 68°C such as, for example, the Mitsui Tafmer™ grades A- 1085, A-4085, A-4090 and A-20090, and the like. This reference also discusses the differences between plastomers and elastomers and very low density polyethylene. Summary of the Present Invention

[0005] A feature that is important in many applications, but not yet optimized in any of the prior art documents, is the elastomeric behavior over time at elevated temperatures (70, 100 and 125°C), expressed as compression set (ISO-815) or stress relaxation (ISO-3384).

[0006] In most applications where a hardness of about 40-60 Shore A is desired or necessary, an ideal composition has a compression set (CS) measured over e.g. 24 hours of: at 70°C <50% and preferably <40%,

at 100°C <70% and preferably <60%, and

at 125°C <80% and preferably <70%.

Furthermore, the long-term elastic behavior, expressed as remaining force (in % of original force) after 1000 hours compression (at 25%), measured at 70°C, should be 40% or more.

[0007] The present invention fulfills this long-felt need. Thus, a novel thermoplastic elastomer composition has been developed having a durometer hardness (ASTM D2240) of Shore A in the range of 30 to 90 comprising:

a) 100 parts by weight of a hydrogenated styrenic block copolymer, such as Kraton G1640, G1640, G1651, G1633, polymers from the E1800 series and MD6944,

b) from 20 to 150 parts by weight of a polyolefin mixture of a high density polyethylene (HDPE) and a polypropylene (PP);

c) from 50 to 300 parts by weight of processing oil; and optionally

d) from 0 to 300 parts by weight of a filler. [0008] Although this novel composition has some excellent properties, a need remains for compositions with improved compression set in particular in the window of 80 to 140°C. This need is particularly acute for products that are sterilized with boiling water or subjected to steam sterilization under increased pressure at 120°C. The present invention fulfills this need.

DISCLOSURE OF THE INVENTION

[0009] Accordingly, a new and novel thermoplastic elastomer composition has been invented. The new thermoplastic elastomer composition is a composition having a durometer hardness (ASTM D2240) of Shore A in the range of 30 to 90 comprising:

a) 100 parts by weight of a hydrogenated styrenic block copolymer (HSBC) comprising at least two blocks (A) of a polymer containing 50 wt.% or less monovinyl aromatic hydrocarbon units, and at least one selectively hydrogenated block (B) of a polymer containing 50 wt.% or more conjugated diene units, wherein the monovinyl aromatic hydrocarbon content is in the range of from 10 to 50 wt.%, based on the total weight of block copolymer, wherein the vinyl content in the initially prepared poly (conjugated diene) block (B) is in the range of from 30 to 80 %, and wherein the hydrogenated styrenic block copolymer has a degree of hydrogenation of at least 30%, preferably at least 80%, with respect to the residual olefinic unsaturation in the block (B), which block copolymer optionally may be mixed with a diblock copolymer having one poly (monovinyl aromatic hydrocarbon) block and one poly (conjugated

diene) block, in an amount of up to 40 wt%,

b) from 20 to 150 parts by weight of a polyolefin;

c) from 50 to 300 parts by weight of processing oil; and optionally

d) from 0 to 300 parts by weight of a filler, characterized in that the polyolefin is a mixture of a low softening point polyolefm plastomer or elastomer and a polypropylene.

[0010] The invention is further defined in that the low softening point polyolefin plastomer is a copolymer of ethylene or propylene:

(i) with one or more alpha-olefins as comonomer that is prepared using a single- site catalyst, in particular a metallocene catalyst,

(ii) with between 10 and 50 wt.% of an alpha-olefin, in particular of propylene, butene, hexene or octene, more preferably a mixture of butene and octene are used as comonomer,

(iii) having a molecular weight distribution defined as the ratio Mw/Mn that is between 1.2 and 4.0, preferably between 1.8 and 3.0,

(iv) having a Vicat softening point (ASTM D1525) below 100°C, preferably between 30 and 100°C, more preferably between 40 and 85°C, and

(v) having a density that is between 850 and 910 g/dm³, preferably between 860 and 890 g/dm³. The polyolefin mixture could also contain low softening point polyolefin elastomers, sometimes referred to as POEs, again with a Vicat softening point below 100°C. Polypropylene (PP), has a melt flow rate (MFR) at 230°C/2.16 kg of from 1 to 40 g/10 min., (ASTM D1238). The low softening point polyolefin plastomer or elastomer is in a weight ratio with the polypropylene of from 0.2 to 5.

DESCRIPTION OF THE FIGURES

[0011] Figure 1 is a graph of compression set in % versus temperature comparing prior art and the present invention compositions using Affinity® PL 1280G. [0012] Figure 2 is a graph of compression set in % versus temperature in °C comparing prior art and the present invention compositions using Affinity® EG 8200G.

DESCRIPTION OF THE INVENTION

[0013] In the following discussion, the term "apparent molecular weight" means the molecular weight determined by Liquid High Performance Permeation Size Exclusion Chromatography (LHPSEC) using the method according to ASTM D-5296, and is expressed in terms of polystyrene standard polymers. For anionically polymerized linear polymers, the polymer is essentially monodispersed, and it is both convenient and adequate to report the peak molecular weight of the narrow molecular weight distribution, rather than the number average molecular weight or weight average molecular weight. The peak molecular weight is usually the molecular weight of the main species shown in the chromatograph. For materials to be used in the columns of the GPC, styrene-divinyl benzene gels or silica gels are commonly used and are excellent materials. Tetrahydrofuran is an excellent solvent for polymers of the type described herein. The detector used is preferably a combination ultraviolet and refractive index detector. All molecular weights are measured prior to hydrogenation. Thus after hydrogenation the molecular weights will increase by a small amount.

[0014] The hydrogenated block copolymer is preferably selected from block copolymers that comprise at least two end blocks A, made of polymerized monovinyl aromatic hydrocarbon, thus giving a glossy (resinous) monovinyl aromatic segment, and at least one central block B composed of polymerized, conjugated, hydrogenated diene and preferably of hydrogenated polybutadiene, sometimes referred to as ethyl ene-butylene, which provides an amorphous elastomeric segment. The block copolymer can be linear, represented by the triblock formula A-B-A, or radial as represented by the general formula (A-B)nX, where X is the residue of a coupling agent, or mixtures thereof. Linear and radial block copolymers may also comprise a multitude of alternating A and B blocks.

[0015] The A-B-A triblock copolymer can be made by either sequential polymerization, or by coupling of an initially prepared living block copolymer A-B.

[0016] In the sequential polymerization, the monovinyl aromatic monomer is polymerized in a first step to form a monovinyl aromatic hydrocarbon block, followed by the addition of a batch of conjugated diene. After completion of polymerization of the diene block, addition of more monovinyl aromatic monomer is made and polymerized to form the block copolymer A-B-A. The sequential polymerization process for the manufacture of A-B- A block copolymers is widely known and has in general been disclosed in, for example, US 3,231,635, the disclosure and teachings of which are included herein by reference.

[0017] The A-B-A block copolymers and (A-B)nX block copolymers can be manufactured by coupling of an initially prepared living block copolymer A-B with a coupling agent. The manufacture of coupled A-B-A triblock copolymers or radial (A-B)nX block copolymers has broadly been disclosed in US 5,194,530, the disclosure and teachings of which are included herein by reference.

[0018] The monovinyl aromatic hydrocarbon monomer can contain from 8 to 30 carbon atoms and can consist of a single monomer or of mixtures thereof. Suitable monomers are styrene and substituted styrenes such as o-methylstyrene, p-methylstyrene, dimethylstyrene, [alphaj-methylstyrene, diphenyl ethylenes, and the like. However, styrene is the preferred monomer.

[0019] The conjugated diene can have from 4 to 8 carbon atoms and can consist of a single monomer or of mixtures thereof. Suitable monomers are 1,3 -butadiene, isoprene, or mixtures thereof. However, 1 ,3-butadiene is the preferred diene.

[0020] In general, the polymers useful in this invention may be prepared by contacting the monomer or monomers with an organoalkali metal compound in a suitable solvent at a temperature within the range of from 0°C to 100°C. Particularly effective polymerization initiators are organolithium compounds having the general formula RLi wherein R is an aliphatic, cycloaliphatic, alkyl-substituted aromatic hydrocarbon radical having from 1 to 20 carbon atoms. In a preferred embodiment sec-butyl is preferred.

[0021] Suitable solvents include those useful in the solution polymerization of the polymer of the present invention and include aliphatic, cycloaliphatic, alkyl-substituted cycloaliphatic, aromatic and alkyl-aromatic hydrocarbons. Suitable solvents include butane, straight or in branched pentane, hexane and heptane, cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane and cyclopentane, and alkyl-substituted aromatic hydrocarbons such as toluene and xylene.

[0022] It will be appreciated that during the polymerization of the conjugated diene monomer(s), such as butadiene, they can be incorporated in the growing polymer chain in two ways. Butadiene can be inserted in the 1,4-addition form or in the 1,2-addition form, the latter of which will result in the formation of vinyl groups attached to the backbone polymer chain. It is well known in the art to regulate the polymerization toward the 1,2-addition. Generally, this can be regulated by the use of an ether or amine as disclosed in US 3,686,366, US 3,700,748, and US 5,194,535, the disclosures and teachings of these references hereby being included herein by reference. The vinyl content is in the range of from 30 to 80 mole%, preferably in the range from 35-50 mole% (to be consistent with claim 1).

[0023] As mentioned hereinbefore, the polymers useful in this invention may be prepared using a coupling agent. Suitable coupling agents include tin coupling agents, halogenated silicon coupling agents, alkoxysilanes and alkylalkoxysilanes, epoxy compounds such as the diglycidyl ether of bisphenol A or F, benzoic esters, halogenated alkanes and divinylbenzene, C02, and similar multifunctional compounds.

[0024] It will be appreciated that, depending on the coupling efficiency of the applied coupling agent, a certain amount of non-coupled terminated diblock copolymer will be present in the finally obtained block copolymer.

[0025] Preferably at least 80 wt%, and more in particular from 90 to 100 wt%, of the total block copolymer will be formed by the coupled triblock or radial main block copolymer (i.e. a diblock content of from 0 to 20 wt%). Still more preferably, the diblock contents are from 0 to 5 wt%.

[0026] The thermoplastic elastomers according to the present invention are selectively hydrogenated in the sense that the aliphatic unsaturation of the diene B block(s) is removed for at least 80% of the residual aliphatic unsaturation while leaving unaffected most of the aromatic unsaturation in the A blocks. Said aliphatic unsaturation can be partially or almost completely hydrogenated. Hydrogenation processes are disclosed and discussed in US 3,113,986, US 3,634,549, US 3,670,054, US 3,700,633, US 4,226,952, US RE-27,145, and US 5,039,755, the disclosures and teachings of these references being included herein by reference.

[0027] The apparent molecular weight of the block copolymers according to the present invention will generally be at least 250 kg/mole. For linear A-B-A block copolymers, the apparent molecular weight will generally be within the range of from 250 to 700 kg/mole. It can be appreciated by a person skilled in the art that the upper limit is dictated by viscosity considerations and can be as high as acceptable for a good processability. The preferred molecular weight for linear A-B-A polymers is from 300 to 600 kg/mole, more preferably in the range of from 400 to 500 kg/mole. With radial polymers, the molecular weight can be much higher since these polymers have a lower viscosity for a given total molecular weight. Thus, for radial polymers the molecular weight generally will be in the range from 250 to 1,000 kg/mole, preferably from 400 to 600 kg/mole. If the apparent molecular weight of the block copolymer is too low, then the balance of hardness and compression set will not be achieved.

[0028] The total monovinyl aromatic content of the block copolymer- (e.g., blocks A) is generally within the range of from 10 to 50 weight percent, preferably from 20 to 35 weight percent.

[0029] Block copolymers that may be used as component a) (see paragraphs 0009 and

0010) in the present composition are commercially available. Kraton Polymers supplies the grades Kraton® G1651, G1633, G1641 , MD6944 and MD6917 (now G1640) that will all be suitable. Kuraray provides the Septon™ grades 4055, 4077 and 4099. Asahi provides the grade N504. TSRC provides the grades Taipol™ 3151. Dynasol provides the grades Calprene™ H6170 and H6171, and Polimeri Europa provides the grade Europrene™ TH2315. In a preferred embodiment, the block copolymer is Kraton G1633, wherein the hydrogenated styrenic block copolymer has a peak average molecular weight of at least 250 kg/mole, measured according to ASTM D-5296. In addition to the foregoing, a combination of block copolymer grades may be used, provided that the requirements of component a) are met.

[0030] The polyolefin used as component b) is the key to the surprisingly improved compression set values for the disclosed compounds. Polyolefins suitable for component b) are mixtures of low softening point polyolefin plastomers or elastomers and a polypropylene. The polyolefin plastomer and polyolefin elastomer are a copolymer of ethylene or propylene with one or more alpha-olefins as comonomer that is prepared using a single-site catalyst. In particular, a metallocene catalyst is used to prepare the copolymer. The polyolefin plastomer or elastomer is more preferably a copolymer of ethylene with between 10 and 50 wt. % of an alpha-olefin, in particular of propylene, butene, hexene or octene (more preferably butene and octene), having a Vicat softening point, as determined by ASTM D1525, below 100°C, preferably between 30 and 100°C, and still more preferably between 40 and 85°C. The copolymer has a molecular weight distribution (defined as the ratio Mw/Mn) that is between 1.2 and 4.0, preferably between 1.8 and 3.0, and a density that is between 850 and 910 g/dm , preferably between 860 and 890 g/dm³.

[0031] Polyolefin plastomers and polyolefin elastomers are relatively new polymers typically produced by inter-polymerization of ethylene and one or more alpha-olefins using single-site metallocene systems as a catalyst. They are semi-crystalline, containing both an amorphous phase and a crystalline phase. The polyolefin plastomer is preferably Affinity™ grade, like PL1280G or EG8200G. It may also be a plasticizer produced by Mitsui under its Tafmer trademark. Also a polyolefin elastomer, such as the grade sold under the trademark Engage™, may be used. Preferred polyolefin plastomer and/or polyolefin elastomer has a MFR at 190°C/2.16 kg of from 4 to 8, preferably of from 6 to 6 g/10 min., such as Affinity PL1280G and/or Affinity EG8200G and Mitsui' s Tafmer™ grade range.

[0032] The polypropylene suitable for the mixture is defined as having a MFR at

230°C/2.16 kg of from 1 to 40 g/10 min., (as defined and measured according to ASTM D1238). Further, the weight ratio of polyolefin plastomer and/or polyolefin elastomer to polypropylene should be from 0.2 to 5. Suitable grades include Moplen™ HP501 L (MFR of 25 g/10 min) and Adstiff™ HA722J (MFR of 6 g/lOmin) both from Basell, or H0500 (MFR of 5 g/10 min) from Huntsman.

[0033] Component c) is processing oil. In order to meet the hardness requirement, an amount of from 50 to 300 parts by weight (on 100 parts by weight of the block copolymer) is sufficient. The presence of processing oil in the final composition helps reduce the amount of stress relaxation. Suitable oils for use in the compound are those which are compatible with the elastomeric mid-block diene segment of the elastomeric block copolymer and which do not tend to migrate into the aromatic end-block portions to any significant degree. Thus, the most suitable oils have a higher paraffinic than naphthenic fraction. Paraffmic oils that may be used in the elastomeric composition should be capable of being melt processed with other components of the elastomeric composition without degrading. Particularly important is the ability of the final composition to be melt extruded. Suitable processing oils include white mineral oils available under the trade designations Primol™ 352 from Esso, Drakeol™ 34 from Penreco, and Ondina™ 941 from Shell. Ondina 941 has a specific gravity of 0.868 at 15°C, and a kinetic viscosity of 94 mm² at 40°C. Vegetable oils and animal oils or their derivatives may also be used.

[0034] Component d), the filler, is an optional component. Fillers are typically inert material that is used to reduce the overall cost of the composition, without significantly adversely affecting the properties of the composition. Calcium carbonate and talc are frequently used inert fillers, but other components may be used as well. Suitable grades include Durcal™ 5 from Omya or Vicron™ 25-11 from Stochem. In a preferred embodiment the filler is Durcal™ 5 (CaC0₃).

[0035] Not specifically discussed in detail, but included as further optional components of the claimed thermoplastic elastomer composition are common components such as antioxidants, stabilizers, surfactants, waxes, flow promoters, solvents, processing aids, pigments, dyes and coloring agents, mold release agents and the like, which may be used in typical amounts.

[0036] The block copolymer compositions of the present invention have been found to show a surprisingly attractive balance of physical properties for hardness, compression set, tensile strength, stress relaxation at high temperatures and a low processing viscosity, in comparison to the various prior art block copolymers.

[0037] The thermoplastic elastomeric compositions may be used for the manufacture of shaped articles and in particular those to be applied in the automotive industry. Further, the compounds disclosed herein are particularly suited to home appliance parts, sporting goods, medical devices, food contact applications requiring sterilization, sundry goods, stationary and goods obtained via injection-molding and/or extrusion that typically require a durometer hardness (as defined by ASTM D2240, expressed in Shore A) in the range of 30 - 90. Such products are therefore also provided by this invention.

The Examples

[0038] Compositions of both comparable examples and examples of the present invention were prepared and tested for both Shore A hardness and compression set. The ingredients were based on 100 parts of the styrenic block copolymer. The compositions of comparable examples 1 and 2, the examples of the present invention using Affinity PL 1280G, and the examples of the present invention using Affinity EG 8200G are set forth in Table 1. The composition ingredients are simply mixed together in the respective weight ratios to form a preblend, which is used to feed a co-rotating twin screw extruder (Werner & Pfleiderer ZSK25) containing 3 mixing zones to produce a TPE compound. Compound pellets are used to feed an injection molding machine to produce the required samples for testing, and tested for Shore A hardness according to ASTM D2240 and Compression Set according to ISO 815.

[0039]

Table 1

The compositions in Table 1 all had a Shore A hardness between 50 and54. However as illustrated in Figure 1, the compression set for examples 1 and 2 is higher than when employing Affinity PL 1280G and EG 8200G, each with polypropylene, than using polypropylene alone - Example 1 , or polypropylene with HDPE - Example 2, at temperature ranges of about 80 to 125 °C.

[0040] Thus it is apparent that there has been provided, in accordance with the invention, an article that fully satisfies the objects, aims, and advantages set forth herein. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, the invention is intended to embrace all such alternatives, and modifications and variations as fall within the spirit and broad scope of the intended claims.

Claims

1. A thermoplastic elastomer composition having a durometer hardness (ASTM D2240) of Shore A 30 to 90 comprising:

a) 100 parts by weight of a hydrogenated styrenic block copolymer comprising at least two blocks (A) of a polymer containing 50 wt. % or more monovinyl aromatic hydrocarbon units, and at least one selectively hydrogenated block (B) of a polymer containing 50 wt. % or more conjugated diene units, wherein the monovinyl aromatic hydrocarbon content is in the range of from 10 to 50 wt.%, based on the total weight of block copolymer, wherein the vinyl content in the initially prepared poly (conjugated diene) block (B) is in the range of from 30 to 80 %, and wherein the hydrogenated styrenic block copolymer has a degree of hydrogenation of at least 80% with respect to the residual olefinic unsaturation in the block (B), which block copolymer optionally may be mixed with a diblock copolymer having one poly (monovinyl aromatic hydrocarbon) block and one poly (conjugated diene) block, in an amount of up to 40 wt%;

b) from 20 to 150 parts by weight of a polyolefm;

c) from 50 to 300 parts by weight processing oil; and optionally

d) from 0 to 300 parts by weight of a filler;

wherein the polyolefm is a mixture of a low softening point polyolefm plastomer or elastomer and polypropylene in a weight ratio of from 0.2 to 5;

wherein said low softening point polyolefm plastomer or elastomer is a copolymer of ethylene or propylene with one or more alpha-olefins as comonomer, having a Vicat softening point below 100°C, and a density between 850 and 910 g/dm³.

2. A thermoplastic elastomer composition according to claim 1 wherein said low softening point polyolefin plastomer or elastomer is prepared using a single-site catalyst.

3. A thermoplastic elastomer composition according to claim 2 wherein said single-site catalyst is a metallocene catalyst.

4. A thermoplastic elastomer composition of claim 1, wherein said low softening point polyolefin is a copolymer of ethylene or propylene.

5. A thermoplastic elastomer composition according to claim 1 wherein said low softening point polyolefin plastomer or elastomer is a copolymer of ethylene with between 10 and 50 wt. % of an alpha-olefin.

6. A thermoplastic elastomer composition according to claim 1 wherein said comonomer of ethylene is propylene, butene, hexene or octene.

7. A thermoplastic elastomer composition according to claim 1 wherein said comonomer is a mixture of butene and octene.

8. A thermoplastic elastomer composition according to claim 1 wherein said low softening point polyolefin plastomer or elastomer has a molecular weight distribution

(defined as the ratio Mw/Mn) between 1.2 and 4.0.

9. A thermoplastic elastomer composition of claim 8 wherein said low softening point polyolefin plastomer or elastomer has a molecular weight distribution between 1.8 and 3.0.

10. A thermoplastic elastomer composition of claim 1 , wherein said low softening point polyolefin plastomer or elastomer has a Vicat softening point is preferably between 30 and 100°C.

1 1. A thermoplastic elastomer composition according to claim 10, where in said Vicat softening point is preferably between 40 and 85°C.

12. A thermoplastic elastomer composition according to claim 1 , wherein said low softening point polyolefin plastomer or elastomer has a density is between 860 and 890 g/dm³.

13. A thermoplastic elastomer composition according to claim 1 wherein said polypropylene has a MFR at 230°C/2.16 kg of from 1 to 40 g/10 min.

14. A thermoplastic elastomer composition of claim 1 , wherein said low softening point polyolefin plastomer or elastomer are semi-crystalline containing both an amorphous phase and a crystalline phase.

15. A thermoplastic elastomer composition of claim 1, wherein said processing oil is paraffinic oil.

16. Shaped articles manufactured from the thermoplastic elastomeric composition according to claim 1 via compounding followed by injection-molding and/or extrusion.