Thermoplastic composition

Abstract

The present invention relates to a thermoplastic composition comprising, monophasic polypropylene, 0.01 – 5 wt.% of non-aromatic polyester having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester, and 0 - 5 wt.% of optional further components. Such compositions who an improved strain at break.

Description

[0001] 24POLY0106-WO-ORD 1

[0002] THERMOPLASTIC COMPOSITION

[0003] The present invention relates to a thermoplastic composition comprising polypropylene and non-aromatic polyester having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester. The present invention further relates to a method for the manufacture of, and to a compound comprising such a composition.

[0004] WO2016 / 188817 discloses a composition comprising polypropylene, polyethylene and a compatibiliser, wherein said compatibiliser is a non-aromatic polyester having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester. In that disclosure the non-aromatic polyester is used as a compatibiliser leading to a polyethylene and polypropylene blend wherein there is a more gradual transition between the polypropylene and polyethylene phases in the blend and the domain sizes of the dispersed phase are smaller compared to a composition not comprising a compatibiliser.

[0005] WO2016 / 198243 discloses a composition comprising a heterophasic polypropylene containing i) a matrix phase of a propylene homopolymer and / or a propylene copolymer with up to 3 wt.% of ethylene and / or at least one C4- C8a-olefin, the wt.% based on the weight of the copolymer and ii) a disperse phase of an ethylene - C3- C8a-olefin copolymer, wherein the ethylene content is at least 40 wt.% based on the weight of the ethylene - C3- C8a-olefin copolymer, one or more of a compatibiliser, wherein the compatibiliser is i) a non-aromatic polyester having an average M / E ratio of at least 10 and / or ii) a block copolymer comprising a polypropylene block and a polyester block, said polyester being a non-aromatic polyester and having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester, not including the carbonyl carbons and E is the number of ester groups in the polyester.

[0006] The scientific paper “iPP / HDPE blends compatibilized by a polyester: An unconventional concept to valuable products, Kruszynski et al., Sci. Adv. 10, eado 1944 (2024)” discloses blends of isotactic polypropylene and polypentadecalactone and blends of isotactic polypropylene, high density polyethylene and polypentadecalactone. The 24POLY0106-WO-ORD 2 amount of polypentadecalactone is relatively high in those blends. This article was focused around the compatibilisation of isotactic polypropylene and (high density) polyethylene. In the blends of isotactic polypropylene and polypentadecalactone the amount of polypentadecalactone is relatively high (> 5 wt.%).

[0007] Polypropylene is a well-known polymer that is used in a variety of applications. The term polypropylene generally refers to a propylene homopolymer, which may be at least partially atactic, at least partially isotactic and / or at least syndiotactic, a random copolymer of propylene and one or more of ethylene and an a-olefin, or an impact copolymer which comprises a matrix phase comprising a propylene homopolymer or a random copolymer of propylene and one or more of ethylene and an a-olefin and a disperse phase comprising a copolymer of propylene and one or more of ethylene and an a-olefin. The present invention is not directed at impact copolymers comprising a matrix phase and a dispersed phase.

[0008] Compared to polyethylene, polypropylene typically has a much lower strain at break. This means, in simple terms, that a polypropylene article, at a temperature below the melting temperature, can only be stretched in one or more directions to a limited extent before the material breaks.

[0009] Accordingly, it is an object of the present invention to provide for a polypropylene with an improved strain at break properties. More in particular, the present invention is directed at a polypropylene with an improved toughness, defined as the surface beneath the stress-strain curve of a lap shear strength (LSS) test measured in accordance with ISO 527-3. A further object of the invention is to provide a polypropylene based composition having an increased yield stress.

[0010] To that extent the present inventors surprisingly found that this object can be met, at least in part by adding to polypropylene a relatively small amount of non-aromatic polyester having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester. 24POLY0106-WO-ORD 3

[0011] Accordingly, the present invention is directed at a thermoplastic composition comprising, based on the weight of the composition,

[0012] (A) polypropylene

[0013] (B) 0.01 - 5 wt.% of non-aromatic polyester having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester,

[0014] (C) 0 - 5 wt.% of optional further components, wherein the sum of the components (A) - (C) is 100 wt.% and the polypropylene is monophasic.

[0015] Preferably, the amount of non-aromatic polyester is from 0.05 - 5 wt.%, more preferably from 0.1 - 4 wt.%, even more preferably from 0.1 - 2.5 wt.%, most preferably from 0.1 - 1 wt.%, based on the weight of the composition.

[0016] The polypropylene in the composition in accordance with the invention may be any commercially available and known type of monophasic polypropylene. The term monophasic is to be understood in that the polypropylene is not a heterophasic polypropylene copolymer, sometimes referred to as impact polypropylene copolymer.

[0017] Accordingly, the polypropylene may be a propylene homopolymer including atactic polypropylene, isotactic polypropylene and syndiotactic polypropylene. Preferably at least part of the polypropylene homopolymer is isotactic.

[0018] The polypropylene may also be a random copolymer of propylene and one or more of ethylene and an a-olefin.

[0019] The polypropylene may be a propylene - ethylene random copolymer with from 1 - 7 wt.%, preferably 1 - 5 wt.%, more preferably 1 - 3 wt.% of ethylene based on the weight of the random copolymer.

[0020] The polypropylene may be a propylene - C4- C8a-olefin random copolymer with from 1 - 20 wt.%, preferably 1 - 10, more preferably 1-5 wt.% of C4- C8a-olefin based on the weight of the random copolymer. 24POLY0106-WO-ORD 4

[0021] The polypropylene may be a propylene - C4- C8a-olefin random copolymer with both ethylene and one or more of C4- C8a-olefin, wherein the combined amount of comonomer is from 1 - 20 wt.%, preferably 1 - 10, more preferably 1-5 wt.% based on the weight of the random copolymer. For such copolymers the ethylene content is preferably at most 5 wt.% based on the weight of the random copolymer,

[0022] For the avoidance of doubt the skilled person will understand that the (monophasic) polypropylene is not and / or does not comprise a heterophasic polypropylene copolymer comprising a matrix phase and a disperse phase, the matrix phase consisting of a propylene homopolymer and / or a propylene copolymer with up to 3 wt.% of ethylene and / or at least one C4- C8a-olefin, the wt.% being based on the matrix phase, and the disperse phase consisting of an ethylene - C3- C8a-olefin copolymer.

[0023] Isotactic polypropylene is preferred.

[0024] The polypropylene is preferably a propylene homopolymer or a propylene ethylene or a propylene C4- C8a-olefin random copolymer. The random copolymer is preferably a propylene - ethylene random copolymer.

[0025] Preferably the melt flow rate of the polypropylene is from 0.1 - 100 g / 10 min as measured in accordance with ISO 1133 (2.16 kg, 230 °C). More preferably the melt flow rate is from 5.0 to 60 g / 10 min.

[0026] The polyester in the composition according to the present invention is a non-aromatic polyester having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester. With average M / E ratio is meant a numerical average.

[0027] The polyester is non-aromatic meaning the polyester does not contain aromatic groups. 24POLY0106-WO-ORD 5

[0028] The backbone of the polyester is preferably saturated meaning it preferably does not contain any double bonds. It is preferred the backbone of the polyester is (saturated) aliphatic.

[0029] The polyester backbone may, in an embodiment, contain short aliphatic branches such as methyl, ethyl, propyl, butyl, pentyl or hexyl branches. The amount of such branches is preferably kept at a low amount since it may negatively affect the (co)crystallisation behaviour of the polyester block. In another embodiment the backbone contains one or more heteroatoms such as oxygen, nitrogen or sulfur.

[0030] The polyester may be a polyester homopolymer or a polyester copolymer.

[0031] If the polyester is a polyester copolymer, then the number of backbone carbon atoms between two neighbouring ester groups in the backbone is preferably randomly distributed over the polyester. Furthermore, the number of backbone carbon atoms (M) between ester functionalities in polyester copolymers is preferably at least 8, more preferably at least 10, or at least 12.

[0032] Typical examples of polyester homopolymers include the homopolymers obtainable by the ring opening polymerisation of dodecalactone, tridecanolactone, tetradecalactone, pentadecalactone, hexadecalactone, heptadecalactone, octadecalactone, nonadecalactone, ambrettolide, globalide. In other words typical examples of polyester homopolymers include polydodecalactone, polytridecanolactone, polytetradecalactone, polypentadecalactone, polyhexadecalactone, polyheptadecalactone, polyoctadecalactone, polynonadecalactone, polyambrettolide, polyglobalide.

[0033] Typical examples of polyester copolymers include copolymers of at least two lactones from a group including dodecalactone, tridecanolactone, tetradecalactone, pentadecalactone, hexadecalactone, heptadecalactone, octadecalactone, nonadecalactone, ambrettolide, globalide, valerolactone, caprolactone, massoia lactone, b-decalactone, s-decalactone, 13-hexyloxacyclotridec10-en-2-one, 13- hexyloxacyclotridecan-2-one. 24POLY0106-WO-ORD 6

[0034] Other typical examples of polyester copolymers include AABB type copolyesters, i.e. polyester copolymer, prepared of a combination of C2- C3o diols and C2- C32diacids provided the polyester copolymer has an average M / E of at least 10. Further it is preferred that the M / E ratio for the copolymers is at least 8. The term Cxrefers to the total amount of carbon atoms x in the diol or diacid, respectively.

[0035] Diols include, but are not limited to, ethylene glycol, propane-1 , 3-diol, butane-1 ,4-diol, pentane-1 ,5-diol, hexane-1 ,6-diol, heptane-1 ,7-diol, octane-1 , 8-diol, nonane-1 ,9-diol, decane-1 , 10-diol, undecane-1 ,11-diol, dodecane-1 ,12-diol, tridecane-1 ,13-diol, tetradecane-1 , 14-diol, pentadecane- 1 , 15-diol, hexadecane-1 , 16-diol, heptadecane- 1 ,17-diol, octadecane-1 ,18-diol, nonadecane-1 , 19-diol, icosane-1 ,20-diol, henicosane- 1 ,21-diol, docosane-1 ,22-diol, tricosane-1 ,23-diol, tetracosane-1 ,24-diol, pentacosane- 1 ,25-diol, hexacosane-1 , 26-diol, heptacosane-1 ,27-diol, octacosane-1 ,28-diol, nonacosane-1 , 29-diol, triacontane-1 ,30-diol as well as their unsaturated and branched analogues.

[0036] Diacids include, but are not limited to oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octanedioic acid, nonanedioic acid, decanedioic acid, undecandedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, icosanedioic acid, henicosanedioic acid, docosanedioic acid, tricosanedioic acid, tetracosanedioic acid, pentacosanedioic acid, hexacosanedioic acid, heptacosanedioic acid, octacosanedioic acid, nonacosanedioic acid, triacontanedioic acid and their unsaturated and branched analogues. The diols and diacids might also contain a heteroatom in the main chain like an oxygen, nitrogen or sulfur.

[0037] Cyclic carbonic acid esters can also be used as monomer or as comonomer in combination with lactones, dilactones, hydroxyl acids, hydroxy acid esters or diols plus dicarboxylic acids or a combination of these monomers to form polycarbonates or poly(ester-co-carbonate)s with an average M / E of 10 or larger. Examples of cyclic carbonic acid esters are trimethylene carbonate and decamethylene carbonate. 24POLY0106-WO-ORD

[0038] Instead of a combination of one or more diol and diacid, cyclic dilactones can also be added to produce AABB copolyesters with the desired M / E, which is 10 or higher. Typical examples of cyclic dilactones are: ethylene adipate, ethylene brassylate, butylene adipate.

[0039] Another type of polyester copolymers includes AB / AABB copolyesters prepared of a combination of lactones and dilactones and / or the combination of C2- C3o diols and C2- C32diacids, which result in polyesters having an average M / E of at least 10. The lactones, dilactones, diols and diacids can be selected from the lists given above.

[0040] Preferably he polyester is a polyester homopolymer or a polyester copolymer and preferably the polyester is one or more selected from the group consisting of polytetradecalactone, polypentadecalactone, polyhexadecalactone, poly(caprolactone- co-pentadecalactone), poly(s-decalactone-co-pentadecalactone), polyethylene brassylate-co-pentadecalactone), poly[ethylene-1 ,19-nonadecanedioate], poly[ethylene-1 ,23-tricosanedioate], poly[propylene-1 ,19-nonadecanedioate], poly[propylene-1 ,23-tricosanedioate], poly[1 ,4-butadiyl-1 ,19-nonadecanedioate], poly[1 ,4-butadiyl- 1 ,23-tricosanedioate], poly[1 ,6-hexadiyl-1 ,19-nonadecanedioate], poly[1 ,6-hexadiyl-1 ,23-tricosanedioate], poly[1 ,19-nonadecadiyl-1 ,19- nonadecanedioate], poly[1 ,19-nonadecadiyl-1 ,23-tricosanedioate], poly[1 ,23-tricosadiyl-

[0041] 1 .19-nonadecanedioate], poly[1 ,23-tricosadiyl- 1 ,23-tricosanedioate], poly[1 ,20- icosadiyl- 1 ,20-icosa-nedioate], poly[1 ,6-hexadiyl-1 ,20-icosenedionate], poly[propylene-

[0042] 1.20-icosanedionate],

[0043] More in general the polyester or copolyester is of general structure wherein

[0044] Rxis an organic group, preferably an aliphatic group having an average chain length of at least 10 carbon atoms and m is the number of repeating units, which generally is at least 25, such as at least 50, such as at least 100. Practical maximum number of repeating units can be 2,000 or 1 ,000. 24POLY0106-WO-ORD 8

[0045] Organic group Rxis a branched or straight hydrocarbon group optionally containing one or more heteroatoms provided that the atom neighbouring the -O- is a carbon atom, i.e. not a heteroatom. Rxmay contain one or more unsaturations, like -C=C-. Preferably Rxis a branched or straight hydrocarbon group, more preferably Rxis a branched or straight aliphatic group. Rxis preferably a saturated aliphatic group. In that respect the term chain length as used herein refers to the shortest number of atoms between two ester functionalities (O=)C-O-. Hence the “chain length” does not include any optional branches or side groups. For example, if Rxis (C4H8) the chain length is four. Similarly, if Rxis CH2-C(CH3)2-CH2-CH2the chain length is also four. In the general formula above Rxmay be the same or different throughout the polyester provided the average chain length is at least 10 carbon atoms. The following general (co)polyester structures can be considered, which structures are to be considered as more detailed embodiments of the general structure provided above:

[0046] The chain lengths of R1, R2, R3and R4are selected such that for the polyester the average M / E ratio is at least 10. The description for Rxabove also applies for R1-R4.

[0047] It is preferred that the M / E ratio is at most 32. Hence the M / E ratio is preferably from 10 - 32, such as 12 -32 and more preferably from 12 - 24.

[0048] The molecular weight of the polyester may vary and is generally selected such that a material is obtained that can be blended with the polypropylene relatively easily. 24POLY0106-WO-ORD 9

[0049] The number average molecular weight of the polyester is preferably from 5,000 to 250,000 g / mol, more preferably from 10,000 to 100,000 g / mol, said number average molecular weight being determined as the polyethylene-equivalent molecular weight by high temperature size exclusion chromatography performed at 160 °C in trichlorobenzene using polyethylene as standard.

[0050] The polyester may be manufactured by various methods known in the art. For example, the polyesters may be prepared by (1) enzymatic ring-opening polymerization, (2) catalytic ring-opening polymerization using organic catalysts, (3) anionic ring-opening polymerization and catalytic ring-opening polymerization using metal-based catalysts, (4) ADMET (acyclic diene metathesis) or ROMP (ring-opening metathesis) of ester containing dienes or unsaturated cyclic esters, respectively or (5) polycondensation. Enzymatic ring-opening polymerization of cyclic esters, in particular macrolactones (lactones with a ring size larger than 10 atoms) has proven to be a very efficient process. For example Novozyme 435, containing supported Candida Antarctica lipase B can polymerize pentadecalactone within 2 h at 70 °C with over 90% conversion to high molecular weight ( / Wn86,000 g / mol) polypentadecalactone (Bisht, K. S.; Henderson, L. A.; Gross, R. A.; Kaplan, D. L; Swift, G. Macromolecules 1997, 30, 2705-2711 ; Kumar, A.; Kalra, B.; Dekhterman, A.; Gross, R. A. Macromolecules 2000, 33, 6303-6309). Supported Humicola insolenscutinase gave comparable results for pentadecalactone polymerization (Hunson, M.; Abul, A.; Xie, W.; Gross, R. Biomacromolecules 2008, 9, 518-522).

[0051] Organic catalysts such as 1 ,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) selectively ringopen lactones and macrolactones such as pentadecalactone to the corresponding homo and copolymers. Although the conversions are high, in all reported cases the obtained molecular weights of the products remain relatively low (Bouyahyi, M.; Pepels, M. P. F.; Heise, A.; Duchateau, R. Macromolecules 2012, 45, 3356-3366).

[0052] The most well-known route to produce high molecular weight polymacrolactones and lactone-macrolactone copolymers is by anionic or catalytic ring-opening polymerization using metal-based catalysts. A wide variety of catalysts have been applied. Aluminum salen (WO 2012 / 065711 , van der Meulen, I.; Gubbels, E.; Huijser, S.; Sablong, R.; 24POLY0106-WO-ORD 10

[0053] Koning, C. E.; Heise, A.; Duchateau, R. Macromolecules 2011 , 44, 4301-4305) and zinc phenoxyimine (WO 2014 / 188344; Bouyahyi, M.; Duchateau, R. Macromolecules 2014, 47, 517-524; Jasinska-Walc, L; Hansen, M. R.; Dudenko, D.; Rozanski, A.; Bouyahyi, M.; Wagner, M.; Graf, R.; Duchateau, R. Polym. Chem. 2014, 5, 3306-3320) catalysts are among the most active catalysts known for the ring-opening polymerization of macrolactones producing high molecular weight homo- and copolymers. Besides discrete catalysts consisting of a complex ancillary ligand system, simple metal alkoxides can also be applied. For example, KOtBu and Mg(BHT)2THF2proved to be potent catalysts / initiators for the ring-opening polymerization of lactones and macrolactones (Jedlinski, Z.; Juzwa, M.; Adamus, G.; Kowalczuk, M.; Montaudo, M. Macromol. Chem. Phys. 1996, 197, 2923-2929; Wilson, J. A.; Hopkins, S. A.; Wright, P. M.; Dove, A. P. Polym. Chem. 2014, 5, 2691-2694; Wilson, J. A.; Hopkins, S. A.; Wright, P. M.; Dove, A. P. macromolecules 2015, 48, 950-958).

[0054] ADMET and ROMP are interesting methodologies to produce polyesters with high M / E values. The difference between ADMET and ROMP is that the first is a step growth process whereas the latter is a chain growth process. Though, but methods have resulted in polyesters with a significantly high molecular weight. The disadvantage of olefin metathesis is that to obtain the final saturated product, a hydrogenation step is necessary. The process is also rather costly (Fokou, P. A.; Meier, M. A. R. Macromol. Rapid. Commun. 2010, 31, 368-373; Vilela, C.; Silvestre, A. J. D.; Meier, M. A. R. Macromol. Chem. Phys. 2012, 213, 2220-2227; Pepels, M. P. F.; Hansen, M. R.; Goossens, H.; Duchateau, R. Macromolecules 2013, 46, 7668-7677).

[0055] Polycondensation of w-hydroxy fatty acids or w-hydroxy fatty acid esters has been reported using either enzymes or metal-based catalysts. For example, Candida Antarctica lipase B (Novozyme 435) polymerizes w-hydroxy fatty acids, such as 12- hydroxydodecanoic acid, albeit that degrees of polymerization remain rather low (Mahapatro, A.; Kumar, A.; Gross, R. A. Biomacromolecules 2004, 5, 62-68). The same enzyme was also used to copolymerize fatty acid-based diacids with diols to moderately high molecular weight polyesters (Yang, X.; Lu, W.; Zhang, X.; Xie, W.; Cai, M.; Gross, R. A. Biomacromolecules 2010, 11, 259-268). The titanium-catalysed polycondensation of w-hydroxy fatty acid esters proved to be highly efficient resulting in high molecular 24POLY0106-WO-ORD 11 weight polyesters (Liu, C.; Liu, F.; Cai, J.; Xie, W.; Long, T. E.; Turner, S. R.; Lyons, A.;

[0056] Gross, R. A. Biomacromolecules 2011 , 72, 3291-3298).

[0057] Methods for making polyesters suitable for application in the present invention are further disclosed for example in WO 2012 / 065711 , WO 2014 / 203209, WO 2014 / 147546, WO 2016 / 188817, the contents of which are incorporated herein by reference.

[0058] The amount of non-aromatic polyester is preferably from 0.01 - 5 wt.%, preferably 0.05 - 5 wt.%, more preferably 0.1 - 2.5 wt.%, based on the weight of the composition. The amount of polyester may be at most 1.5 wt.%, such as at most 1 wt.%. Accordingly the amount of polyester may be from 0.01 - 1.5 wt.% or 0.01 - 1 wt.%. If the amount of polyester is too low then no noticeable effect on the strain at break is observed. At a certain amount of polyester, the improvement in terms of strain at break will reach a plateau and adding further polyester will not result in a significant improvement anymore. Depending on the type of polypropylene the plateau may be reached within these preferred ranges. Typically, and in particular to balance the cost versus the benefit it is preferred to keep the amount of polyester low.

[0059] The composition in accordance with the invention preferably comprises an amount of component (C) from 0 - 3 wt.%, preferably from 0 - 2 wt.%. The optional component (C) typically comprises commonly used additives for polymer compositions such as antioxidants, inorganic fillers, UV stabilisers, mould release agents, colorants and the like.

[0060] Typically, the component (C) does not comprise a polyolefin. Preferably the thermoplastic composition comprises at most 3 wt.%, based on the weight of the composition, of polyethylene. Preferably the amount of polyethylene is at most 2 wt.%, more preferably at most 1 wt.%. Most preferably the thermoplastic composition does not comprise polyethylene.

[0061] The polypropylene in the thermoplastic composition may comprise or consist of recycled polypropylene, in particular mechanically recycled polypropylene. The amount of recycled polypropylene may be from 10 - 100 wt.%, such as 20 - 80 wt.% of 40 - 60 wt.% based on the weight of the polypropylene. In particular mechanically recycled 24POLY0106-WO-ORD 12 polypropylene may contain some amount of polyethylene as a contaminant. The amount of recycled polypropylene is accordingly selected such that in the thermoplastic composition the amount of such polyethylene is at most 3 wt.%, based on the weight of the composition.

[0062] The composition in accordance with the invention preferably has a strain at break, determined in accordance with ISO 527-3 which is at least 10% higher compared to an otherwise identical thermoplastic composition not comprising the non-aromatic polyester (B). More preferably the strain at break is at least 50% higher, even more preferably at least 100% higher.

[0063] The present invention further relates to an article comprising or consisting of the thermoplastic composition disclosed herein. Preferably the thermoplastic composition of the invention is used for the manufacture of articles wherein strain at break is an important property. Such applications include bitumen containing roofing materials like shingles. In another application the thermoplastic composition constitutes or is comprised in a pipe or a film.

[0064] Alternatively, or in addition the present invention allows for the use of recycled polypropylene which, due to its prior use and recycling, shows inferior mechanical properties compared to the properties at the time it was produced. By addition of the component (B) at least the strain at break of the recycled polypropylene can be improved.

[0065] The present invention further relates to the use of a non-aromatic polyester having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester as an additive in a thermoplastic composition comprising polypropylene, for improving the strain at break as determined in accordance with ISO 527-3.

[0066] Method

[0067] Methods for the manufacture of thermoplastic composition of the invention are known per se and include typical melt mixing processes carried out either in batch or continuous form. 24POLY0106-WO-ORD 13

[0068] Thus, the present invention relates to a method for the manufacture of a thermoplastic composition as disclosed herein comprising the steps of i) providing a stream of monophasic polypropylene (A) ii) combining said stream of polypropylene with at least one non-aromatic polyester (B) having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester and optionally with 0 - 5 wt.% based on the weight of thermoplastic composition, of optional further components (C).

[0069] The preferred features set out above with respect to the polypropylene, the polyester and the composition also apply in the same manner to the method of manufacture of the composition. Thus, the polypropylene is preferably a polypropylene homopolymer, random polypropylene copolymer, impact polypropylene copolymer comprising a matrix phase and a dispersed rubber phase.

[0070] In an aspect, the method of the invention the polypropylene comprises or consists of recycled polypropylene. More in particular, in this aspect the recycled polypropylene is mechanically recycled polypropylene comprising at most 3 wt.% of polyethylene.

[0071] While the present invention is primarily directed at the thermoplastic composition disclosed herein, the present invention further includes the use of such composition for the manufacture of compounds.

[0072] Accordingly, the present invention further relates to a thermoplastic compound comprising the composition as disclosed herein and at least one inorganic filler and / or at least one impact modifier, provided that the compound preferably does not comprise polyethylene.

[0073] Test methods and

[0074] All compositions were prepared using the same procedure, only differing in the amounts of polypropylene and polypentadecalactone (PPDL). The appropriate amounts of components were measured, mixed with antioxidant Irganox 1010, and fed into a corotating twin-screw extruder heated to 190°C and a screw rotation rate set at 130 rpm resulting in a residence time of about 1 .5 min. 24POLY0106-WO-ORD 14

[0075] Film samples were prepared via compression-molding using a LabEcon 600 high- temperature press (Fontijne Presses, the Netherlands). The following compressionmolding cycle was applied: heating to 190 °C, stabilizing for 5 min with no force applied, 5 min with 100 kN normal force and followed by cooling to 40 °C with 10 °C / min and 100 kN normal force.

[0076] Weight average molecular weight ( / Ww) and Number average molecular weight (Mn): is determined in accordance with ASTM D6474-12. SEC measurements were performed at 150 °C on a Polymer Char GPC-IR® built around an Agilent GC oven model 7890, equipped with an autosampler and the Integrated Detector IR4. 1 ,2-Dichlorobenzene (o- DCB) was used as an eluent at a flow rate of 1 mL / min. The data were processed using Calculations Software GPC One®. The molecular weights ( / Wn, Mw) were calculated with respect to polystyrene standards. Polydispersity index (£)) is calculated by dividing the weight average molecular weight ( / Ww) by the number average molecular weight ( / Wn) and wherein each of / Wwand Mnare measured in accordance with ASTM D6474-12.

[0077] The peak melting (Tm) and crystallization (Tc) temperature was determined using Differential Scanning Calorimetry (DSC) in accordance with ASTM D3418-15. Using a nitrogen purge gas at a flow rate of 50 ± 5 mL / min, two heating and cooling cycles between -40 °C to 230 °C and a heating and cooling rate of 10 °C / min were used. The peak melting temperature was determined using the second heating cycle.

[0078] The mechanical properties of the test samples were determined using a Zwick type Z020 tensile tester equipped with a 1.0 kN load cell according to ISO 527-3 standard (specimen type B5). A grip-to-grip separation of 15 mm was used. The samples were pre-stressed to 3 N, then loaded with a constant crosshead speed 15 mm / min.

[0079] The polypropylene of the examples was SABIC PP 527K, a high molecular weight isotactic propylene homopolymer having a melt flow rate (MFR) of 3.0 dg / min determined in accordance with ISO 1 133 (230 °C; 2.16 kg) The polypropylene had a melting point of 166 °C. 24POLY0106-WO-ORD 15

[0080] The polyester was polypentadecalactone with a number average molecular weight, Mnof 99 kg / mol (determined via gel-permeation chromatography in accordance with ASTM D6474-12 using polystyrene standards) and a polydispersity (weight-average molecular weight divided by the number average molecular weight, / Ww / / Wn) of 2.3. The polyester of the examples revealed the melting point of 95.5 °C.

[0081] The following thermoplastic compositions were manufactured.

[0082] E X A M P L E S The present inventors surprisingly found that addition of PPDL to the polypropylene results in a significant increase of the strain at break, without however jeopardising the intrinsic strength of the polypropylene. Inventors conclude that even a small amount of 24POLY0106-WO-ORD 16 polyester added to the polypropylene will result in a significant increase in the strain at break indicative for a significant toughening of the polypropylene.

Claims

24POLY0106-WO-ORD 17C L A I M S1 . Thermoplastic composition comprising, based on the weight of the composition,(A) polypropylene(B) 0.01 - 5 wt.% of non-aromatic polyester having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester,(C) 0 - 5 wt.% of optional further components, wherein the sum of the components (A) - (C) is 100 wt.% and the polypropylene is monophasic.

2. The composition of claim 1 wherein the amount of non-aromatic polyester is from 0.05 - 5 wt.%, preferably from 0.1 - 4 wt.%, more preferably from 0.1 - 2.5 wt.%, most preferably from 0.1 - 1 wt.%, based on the weight of the composition.

3. The composition of any one or more of claims 1 - 2 wherein the amount of component (C) is from 0 - 3 wt.%, preferably from 0 - 2 wt.%.

4. The composition of any one or more of claims 1 - 3 wherein the composition does not comprise more than 3 wt.%, preferably not more than 1 wt.%, more preferably not more than 0.1 wt.% of polyethylene.

5. The composition of any one or more of claims 1 - 4 wherein the composition has a strain at break, determined in accordance with ISO 527-3, which is at least 10% higher, preferably at least 50% higher, more preferably at least 100% higher, compared to an otherwise identical thermoplastic composition not comprising the non-aromatic polyester (B).

6. The composition of any one or more of claims 1 - 5 wherein the M / E ratio of the non- aromatic polyester is from 12 - 32.

7. The composition of any one or more of claims 1 - 6 wherein the polyester is a polyester homopolymer or a polyester copolymer and preferably the polyester is one24POLY0106-WO-ORD 18 or more selected from the group consisting of polytetradecalactone, polypentadecalactone, polyhexadecalactone, poly(caprolactone- copentadecalactone), poly(s-decalactone-co-pentadecalactone ), poly( ethylene brassylate-co-pentadecalactone ), poly[ ethylene-1 , 19-nonadecanedioate], poly[ ethylene-1 ,23-tricosanedioate], polypropylene- 1 , 19-nonadecanedioate], poly[propylene-1 ,23-tricosanedioate], poly [ 1 ,4-butad iy I- 1 , 19-nonadecanedioate], poly[1 ,4-butadiyl-1 ,23-tricosanedioate], poly[1 ,6-hexadiyl-1 , 19-nonadecanedioate], poly[1 ,6-hexadiyl-1 ,23-tricosanedioate], poly[1 , 19-nonadecadiyl-1 , 19- nonadecanedioate], poly[1 , 19-nonadecadiyl-1 ,23-tricosanedioate], poly[1 ,23- tricosadiyl-1 , 19-nonadecanedioate], poly[1 ,23-tricosadiyl-1 ,23-tricosanedioate], poly[1 ,20-icosadiyl-1 ,20-icosa-nedioate], poly[1 ,6-hexadiyl-1 ,20-icosenedionate], poly[propylene-1 ,20-icosanedionate],8. Method for the manufacture of a thermoplastic composition according to any one or more of claims 1 - 7 comprising the steps of i) providing a stream of monophasic polypropylene (A) ii) combining said stream of polypropylene with 0.01 - 5 wt.%, based on the weight of the thermoplastic composition, of at least one non-aromatic polyester (B) having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester and optionally with 0 - 5 wt.% based on the weight of thermoplastic composition, of optional further components (C).

9. The method of claim 8 wherein the polypropylene is a polypropylene homopolymer or a random polypropylene copolymer.

10. The method of claim 8 or 9 wherein the polypropylene comprises recycled polypropylene.11 . Thermoplastic compound comprising the composition of any one or more of claims 1 - 7, or the thermoplastic composition obtainable by the method of any one or more of claims 8 - 10, and at least one inorganic filler and / or at least one impact modifier.24POLY0106-WO-ORD 1912. An article comprising or consisting of the thermoplastic composition of any one or more of claims 1 - 7 or the compound of claim 11 .

13. Use of a non-aromatic polyester having an average M / E ratio of at least 10, wherein M is the number of backbone carbon atoms in the polyester not including the carbonyl carbons and E is the number of ester groups in the polyester as an additive in a thermoplastic composition comprising polypropylene, for improving the strain at break as determined in accordance with ISO 527-3

Images