WO2024223264A1

WO2024223264A1 - Propylene-based copolymer compositon

Info

Publication number: WO2024223264A1
Application number: PCT/EP2024/059302
Authority: WO
Inventors: Marco BOCCHINO; Claudio Cavalieri; Antonio RIEMMA; Alberta DE CAPUA; Eleonora Ciaccia; Davide TARTARI; Cristina COVA; Alessia DI CAPUA; Marco Ciarafoni; Giampaolo Pellegatti
Original assignee: Basell Poliolefine Italia SRL
Current assignee: Basell Poliolefine Italia SRL
Priority date: 2023-04-26
Filing date: 2024-04-05
Publication date: 2024-10-31
Anticipated expiration: 2025-10-26
Also published as: CN121039224A

Abstract

A polyolefin composition comprising: A) from 50 wt% to 80 wt%;of a copolymer of propylene with ethylene wherein: the content of ethylene, is comprised between 2.5 wt% and 6.5 wt%; B) from 20 wt% to 50 wt%; of a propylene ethylene copolymer containing from 40.0 wt% to 65.0 wt%; of ethylene derived units, measured by NMR; wherein the resulting polyolefin composition has: a melt flow rate (ISO 1133 (230° C, 21.6 kg). ranging from 0.1 g/10min to 3.0 g/10 min; the xylene solubles at 25°C ranges from 23 wt% to 43.0wt%; the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the fraction soluble in xylene at 25°C ranges from 7.7 dl/g to 15.0 dl/g; the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the whole composition ranges from 7.7 dl/g to 15.0 dl/g; the sum A+B being 100.

Description

TITLE

PROPYLENE-BASED COPOLYMER COMPOSITON

FIELD OF THE INVENTION

[0001] The present disclosure relates to a composition comprising propylene ethylene copolymers. The composition having an high molecular weight and high abrasion resistant. The composition is particularly fit for the production of molding objects.

BACKGROUND OF THE INVENTION

[0002] It is well known in the polymer field that different applications require specifically tailored polymers to achieve the individual demanding properties..

[0003] Abrasion resistance is an important characteristics of articles made from polymeric materials, in particular for polypropylene, for many applications. For example in automotive industry wherein there is the need of durable plastic products as exterior and interior parts especially if they are part of moving parts such as gears.

[0004] Therefore there is the need to develop a composition comprising propylene ethylene copolymers to be used in molded object having a enhanced abrasion resistance.

SUMMARY OF THE INVENTION

[0005] A polyolefin composition comprising:

A) from 50 wt% to 80 wt%;of a copolymer of propylene with ethylene wherein: i) the content of ethylene derived units, measured by NMR, is comprised between 2.5 wt% and 6.5 wt%;

B) from 20 wt% to 50 wt%; of a propylene ethylene copolymer containing from 40.0 wt% to 65.0 wt%; of ethylene derived units, measured by NMR; wherein the resulting polyolefin composition has: i) the content of ethylene derived units, measured by NMR, is comprised between 12.0 wt% and 35 wt%; ii) the content of ethylene derived units, measured by NMR, in the fraction soluble in xylene at 25° is comprised between 35.0 wt% and 56.0 wt%; iii) a melt flow rate (ISO 1133 (230° C, 21.6 kg), ranging from 0.1 g/lOmin to 3.0 g/10 min; iv) the xylene solubles at 25 °C ranges from 23 wt% to 43.0wt%; v) the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the fraction soluble in xylene at 25°C ranges from 7.7 dl/g to 15.0 dl/g; vi) the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the whole composition ranges from 7.7 dl/g to 15.0 dl/g; the sum A+B being 100.

DETAILED DESCRIPTION OF THE IN VENTION

[0006] Thus an object of the present disclosure is a polyolefin composition comprising:

A polyolefin composition comprising:

A) from 50 wt% to 80 wt%; preferably from 57 wt% to 77 wt%; more preferably from 63 wt% to 72 wt% of a copolymer of propylene with ethylene wherein: i) the content of ethylene derived units, measured by NMR, is comprised between 2.5 wt% and 6.5 wt%; preferably between 3.5 wt% and 5.5 wt% more preferably between3.8 wt% and 5.0 wt%;;

B) from 20 wt% to 50 wt%; preferably from 23 wt% to 43 wt%; more preferably from 28 wt% to 37 wt% of a propylene ethylene copolymer containing from 40.0 wt% to 65.0 wt%; preferably from 45 wt% to 58 wt%; more preferably from 48 wt% to 55 wt% of ethylene derived units, measured by NMR; wherein the resulting polyolefin composition has: i) the content of ethylene derived units, measured by NMR, is comprised between 12.0 wt% and 35 wt%; preferably between 15.0 wt% and 30 wt%; more preferably between 19.0 wt% and 28.0 wt%; ii) the content of ethylene derived units, measured by NMR, in the fraction soluble in xylene at 25° is comprised between 35.0 wt% and 56.0 wt%; preferably between 38.0 wt% and 51.0 wt%; more preferably between 43.0 wt% and 49.0 wt%; iii) a melt flow rate (ISO 1133 (230° C, 21.6 kg), ranging from 0.1 g/lOmin to 3.0 g/10 min; preferably from 0.5 g/lOmin to 2.5 g/10 min; more preferably from 0.8 g/lOmin to 1.8 g/10 min; iv) the xylene solubles at 25 °C ranges from 23 wt% to 43.0wt%; preferably ranges from 28 wt% to 40.0wt%; more preferably ranges from 29.5 wt% to 28.5 wt%; v) the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the fraction soluble in xylene at 25°C ranges from 7.7 dl/g to 15.0 dl/g; preferably ranges from 7.9 dl/g to 13.0 dl/g; more preferably ranges from 8.1 dl/g to 11.5 dl/g; vi) the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the whole composition ranges from 7.7 dl/g to 15.0 dl/g; preferably ranges from 7.9 dl/g to 13.0 dl/g; more preferably ranges from 8.1 dl/g to 11.5 dl/g;

[0007] the sum A+B being 100. The term copolymer has to be intended as a bipolymer containing two monomers, propylene and a ethylene.

[0008] Preferably the polyolefin composition of the present disclosure is endowed with the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the of the fraction insoluble in xylene at 25°C ranges from 6.5 dl/g to 11.3 dl/g; preferably ranges from 6.8 dl/g to 10.3 dl/g; more preferably ranges from 7.2 dl/g to 9.5 dl/g.

[0009] Preferably the polyolefin composition of the present disclosure is endowed with the content of ethylene derived units, measured by NMR, of the fraction insoluble in xylene at 25 °C is comprised between 8.3 wt% and 17.3 wt%; preferably is comprised between 10.5 wt% and 15.5 wt%; more preferably is comprised between 12.2 wt% and 14.6 wt%.

[0010] The polyolefin composition of the present disclosure shows a low value of abrasion resistance measured according to ISO 15527 : 2007. The value of average abrasion index measured according to ISO 15527 : 2007, on compression molded plaque can be lower than 150 preferably lower than 100; more preferably lower than 93. Preferably the higher value of average abrasion index measured according to ISO 15527 : 2007 is 10.

[0011] Preferably the propylene copolymer of the present disclosure shows a charpy impact test at 23°C ranging from 40 kJ/m2 to 70.0 kJ/m2; preferably from 50.5 kJ/m2 to 65.0 kJ/m2.

[0012] Preferably the propylene copolymer of the present disclosure shows a haze value measured on 1 mm plaque comprised between 37.0 % and 67.4 %; preferably comprised between 47.0 % and 60.4 %.

[0013] non Therefore the polyolefin composition of the present disclosure if particularly fit for the production of molded articles that can be for example an injection molded article, a blow molded article or a compression molded article. Preferably the molded article of the present disclosure is a compression molded article. [0014] The low value of abrasion index renders the molded article of the present disclosure particularly fits for producing automotive articles especially articles subjected to movement.

[0015] The composition of the present disclosure can also be prepared by blending component A) and B). Components (A) and (B) can be also prepared in a continuous sequential polymerization process, wherein component A) is prepared in the first reactor and component (B) is prepared in the second reactor in the presence of component A) according to the known techniques and operating in gas phase, or in liquid phase in the presence or not of inert diluent, or by mixed liquidgas techniques.

[0016] The polymerization of A) and B) can be carried out in the presence of Ziegler-Natta catalysts. An essential component of said catalysts is a solid catalyst component comprising a titanium compound having at least one titanium-halogen bond, and an electron-donor compound, both supported on a magnesium halide in active form. Another essential component (co-catalyst) is an organoaluminium compound, such as an aluminium alkyl compound.

[0017] An external donor is optionally added.

[0018] The catalysts generally used in the process of the invention are capable of producing polypropylene with a value of xylene insolubility at ambient temperature greater than 90%, preferably greater than 95%.

[0019] Catalysts having the above mentioned characteristics are well known in the patent literature; particularly advantageous are the catalysts described in US patent 4,399,054 and European patent 45977. Other examples can be found in US patent 4,472,524.

[0020] The solid catalyst components used in said catalysts comprise, as electron-donors (internal donors), compounds selected from the group consisting of ethers, ketones, lactones, compounds containing N, P and/or S atoms, and esters of mono- and dicarboxylic acids.

[0021] Particularly suitable electron-donor compounds are esters of succinic acid (succinates) Preferably, the succinate present in the solid catalyst component is selected from succinates of formula (I) below

[0022] in which the radicals R1 and R2, equal to, or different from, each other are a C1-C20 linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group, optionally containing heteroatoms; and the radicals R3 and R4 equal to, or different from, each other, are Cl- C20 alkyl, C3-C20 cycloalkyl, C5-C20 aryl, arylalkyl or alkylaryl group with the proviso that at least one of them is a branched alkyl; said compounds being, with respect to the two asymmetric carbon atoms identified in the structure of formula (I), stereoisomers of the type (S,R) or (R,S) [0023] R1 and R2 are preferably C1-C8 alkyl, cycloalkyl, aryl, arylalkyl and alkylaryl groups. Particularly preferred are the compounds in which R1 and R2 are selected from primary alkyls and in particular branched primary alkyls. Examples of suitable R1 and R2 groups are methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl, 2-ethylhexyl. Particularly preferred are ethyl, isobutyl, and neopentyl.

[0024] Particularly preferred are the compounds in which the R3 and/or R4 radicals are secondary alkyls like isopropyl, sec-butyl, 2-pentyl, 3 -pentyl or cycloakyls like cyclohexyl, cyclopentyl, cyclohexylmethyl.

[0025] Examples of the above-mentioned compounds are the (S,R) (S,R) forms pure or in mixture, optionally in racemic form, of diethyl 2,3-bis(trimethylsilyl)succinate, diethyl 2,3-bis(2- ethylbutyl)succinate, diethyl 2,3 -dibenzylsuccinate, diethyl 2,3-diisopropylsuccinate, diisobutyl

2.3 -diisopropylsuccinate, diethyl 2,3-bis(cyclohexylmethyl)succinate, diethyl 2,3- diisobutylsuccinate, diethyl 2,3 -dineopentylsuccinate, diethyl 2, 3 -di cyclopentylsuccinate, diethyl

2.3 -di cyclohexylsuccinate.

[0026] Particularly suitable electron-donor compounds are esters of phtalic acid and 1,3- diethers of formula:

[0027] wherein R¹ and Rⁿ are the same or different and are Ci-Cis alkyl, C3-C18 cycloalkyl or C7-C18 aryl radicals; R¹¹¹ and R^IV are the same or different and are C1-C4 alkyl radicals; or are the 1,3 -di ethers in which the carbon atom in position 2 belongs to a cyclic or polycyclic structure made up of 5, 6, or 7 carbon atoms, or of 5-n or 6-n' carbon atoms, and respectively n nitrogen atoms and n' heteroatoms selected from the group consisting of N, O, S and Si, where n is 1 or 2 and n' is 1, 2, or 3, said structure containing two or three unsaturations (cyclopolyenic structure), and optionally being condensed with other cyclic structures, or substituted with one or more substituents selected from the group consisting of linear or branched alkyl radicals; cycloalkyl, aryl, aralkyl, alkaryl radicals and halogens, or being condensed with other cyclic structures and substituted with one or more of the above mentioned substituents that can also be bonded to the condensed cyclic structures; one or more of the above mentioned alkyl, cycloalkyl, aryl, aralkyl, or alkaryl radicals and the condensed cyclic structures optionally containing one or more heteroatom(s) as substitutes for carbon or hydrogen atoms, or both.

[0028] Ethers of this type are described in published European patent applications 361493 and 728769.

[0029] Representative examples of said diethers are 2-methyl-2-isopropyl-l,3- dimethoxypropane, 2,2-diisobutyl-l ,3-dimethoxypropane, 2-isopropyl-2-cyclopentyl-l ,3- dimethoxypropane, 2-isopropyl-2-isoamyl-l,3-dimethoxypropane, 9,9-bis (methoxymethyl) fluorene.

[0030] Other suitable electron-donor compounds are phthalic acid esters, such as diisobutyl, dioctyl, diphenyl and benzylbutyl phthalate.

[0031] The preparation of the above mentioned catalyst component is carried out according to various methods.

[0032] For example, a MgC12»nROH adduct (in particular in the form of spheroidal particles) wherein n is generally from 1 to 3 and ROH is ethanol, butanol or isobutanol, is reacted with an excess of TiC14 containing the electron-donor compound. The reaction temperature is generally from 80 to 120° C. The solid is then isolated and reacted once more with TiC14, in the presence or absence of the electron-donor compound, after which it is separated and washed with aliquots of a hydrocarbon until all chlorine ions have disappeared.

[0033] In the solid catalyst component the titanium compound, expressed as Ti, is generally present in an amount from 0.5 to 10% by weight. The quantity of electron- donor compound which remains fixed on the solid catalyst component generally is 5 to 20% by moles with respect to the magnesium dihalide.

[0034] The titanium compounds, which can be used for the preparation of the solid catalyst component, are the halides and the halogen alcoholates of titanium. Titanium tetrachloride is the preferred compound.

[0035] The reactions described above result in the formation of a magnesium halide in active form. Other reactions are known in the literature, which cause the formation of magnesium halide in active form starting from magnesium compounds other than halides, such as magnesium carboxylates.

[0036] The Al-alkyl compounds used as co-catalysts comprise the Al-trialkyls, such as Al- triethyl, Al-triisobutyl, Al-tri-n-butyl, and linear or cyclic Al-alkyl compounds containing two or more Al atoms bonded to each other by way of O or N atoms, or SO4 or SO3 groups.

[0037] The Al-alkyl compound is generally used in such a quantity that the Al/Ti ratio be from 1 to 1000.

[0038] The electron-donor compounds that can be used as external donors include aromatic acid esters such as alkyl benzoates, and in particular silicon compounds containing at least one Si- OR bond, where R is a hydrocarbon radical.

[0039] Examples of silicon compounds are (tert-butyl)2Si(OCH3)2, (cyclohexyl)(methyl)Si (OCH3)2, (cyclopentyl)2Si(OCH3)2 and (phenyl)2Si(OCH3)2 and (1,1,2- trimethylpropyl)Si(OCH3)3.

[0040] 1,3 -diethers having the formulae described above can also be used advantageously. If the internal donor is one of these diethers, the external donors can be omitted.

[0041] In particular, even if many other combinations of the previously said catalyst components may allow to obtain compositions according to the present invention, the component A) are preferably prepared by using catalysts containing a phthalate as internal donor and (cyclopentyl)2Si(OCH3)2 as outside donor, or the said 1,3-diethers as internal donors.

[0042] A further The Ziegler-Natta catalysts that can be used to produce a propylene polymer of the present invention is a solid catalyst component comprising a magnesium halide, a titanium compound having at least a Ti-halogen bond as above described and at least two electron donor compounds selected from succinates and the other being selected from 1,3 diethers. [0043] The following examples are given to illustrate the present invention without limiting purpose.

EXAMPLE

Characterization methods

Melting temperature and crystallization temperature: Determined by differential scanning calorimetry (DSC)

[0044] weighting 6 ±1 mg, is heated to 220 ±1° C at a rate of 20 °C/min and kept at 220 ±1° C for 2 minutes in nitrogen stream and it is thereafter cooled at a rate of 20° C/min to 40 ±2° C, thereby kept at this temperature for 2 min to crystallize the sample. Then, the sample is again fused at a temperature rise rate of 20° C/min up to 220° C ±1. The melting scan is recorded, a thermogram is obtained, and, from this, melting temperatures and crystallization temperatures are read.

Melt Flow Rate: Determined according to the method ISO 1133 (230° C, 21.6 kg).

Xylene-soluble fraction (XS) at 25°C

[0045] Xylene Solubles at 25°C have been determined according to ISO 16152: 2005; with solution volume of 250 ml, precipitation at 25°C for 20 minutes, 10 of which with the solution in agitation (magnetic stirrer), and drying at 70°C.

Intrinsic Viscosity (LV.)

[0046] The sample is dissolved by tetrahydronaphthalene at 135 °C and then it is poured into the capillary viscometer.

[0047] The viscometer tube (Ubbelohde type) is surrounded by a cylindrical glass jacket; this setup allows temperature control with a circulating thermostated liquid.

[0048] The downward passage of the meniscus is timed by a photoelectric device. The passage of the meniscus in front of the upper lamp starts the counter which has a quartz crystal oscillator. The meniscus stops the counter as it passes the lower lamp and the efflux time is registered: this is converted into a value of intrinsic viscosity through

Ethylene content in the copolymers

[0049] 13C NMR spectra were acquired on a Bruker AV-600 spectrometer equipped with cry oprobe, operating at 160.91 MHz in the Fourier transform mode at 120 °C.

[0050] The peak of the SPP carbon (nomenclature according to “Monomer Sequence Distribution in Ethylene-Propylene Rubber Measured by 13C NMR. 3. Use of Reaction Probability Mode ” C. J. Carman, R. A. Harrington and C. E. Wilkes, Macromolecules, 1977, 10, 536) was used as an internal reference at 29.9 ppm. The samples were dissolved in 1, 1,2,2- tetrachloroethane-d2 at 120 °C with a 8 % wt/v concentration. Each spectrum was acquired with a 90° pulse, and 15 seconds of delay between pulses and CPD to remove 1H-13C coupling. 512 transients were stored in 32K data points using a spectral window of 9000 Hz.

[0051] The assignments of the spectra, the evaluation of triad distribution and the composition were made according to Kakugo (“Carbon- 13 NMR determination of monomer sequence distribution in ethylene-propylene copolymers prepared with 5-titanium trichloride- diethylaluminum chloride” M. Kakugo, Y. Naito, K. Mizunuma and T. Miyatake, Macromolecules, 1982, 15, 1150) using the following equations:

PPP = 100 Tpp/S PPE = 1OO TP5/S EPE = 100 T55/S

PEP = 100 SPP/S PEE= 100 SP5/S EEE = 100 (0.25 SyS+0.5 S55)/S

S = TPP + TP5 + T55 + SPP + SP5 + 0.25 Sy5 + 0.5 S55

[0052] The molar percentage of ethylene content was evaluated using the following equation: E% mol = 100 * [PEP+PEE+EEE]

[0053] The weight percentage of ethylene content was evaluated using the following equation:

100 * E% mol * MWE

E% wt. = E% mol * MWE + P% mol * MWP

[0054] where P% mol is the molar percentage of propylene content, while MWE and MWP are the molecular weights of ethylene and propylene, respectively.

[0055] The product of reactivity ratio rlr2 was calculated according to Carman (C.J. Carman,

R.A. Harrington and C.E. Wilkes, Macromolecules, 1977; 10, 536) as:

[0056] The tacticity of Propylene sequences was calculated as mm content from the ratio of the PPP mmTPP (28.90-29.65 ppm) and the whole TPP (29.80-28.37 ppm). [0057] The content of ethylene of component B) has been calculated by using the relation: C2tot=XAC2 A+XB C2B ;

[0058] Wherein C2tot is the amount of ethylene in the whole composition C2A and C2B are the amount of component A and B and XA and XB are the amounts of components A and B (A+B=l)

Preparation of injection molded specimens: test specimens 80 x 10 x 4 mm were obtained according to the method ISO 1873-2:2007.

Charpy Impact test at 23°C: measured according to ISO 179-1:2010 on injection molded specimens.

Haze

[0059] Measured according to ASTM D1003 on 1 mm injection molded plaque.

Example 1

Procedure for the preparation of the solid catalyst component

[0060] The solid catalyst used in the following examples was prepared according to the Example 10 of the International Patent Application WO 00/63261. Triethylaluminium (TEAL) was used as co-catalyst and dicyclopentyldimethoxysilane as external donor, with the weight ratios indicated in Table 1.

Polymerization

[0061] The polymerization run is conducted in continuous mode in a series of three reactors equipped with devices to transfer the product from one reactor to the one immediately next to it. The first two reactors are liquid phase reactors, and the third is a fluid bed gas phase reactor. Component (A) is prepared in the first and second reactor, the first and second reactor have the same polymeriziton parameters, while component (B) is prepared in the third.

[0062] Hydrogen is used as molecular weight regulator.

[0063] The gas phase (propylene, ethylene and hydrogen) is continuously analyzed via gaschromatography.

[0064] At the end of the run the powder is discharged and dried under a nitrogen flow.

[0065] The main polymerization conditions are reported in Table 1. Table 1

C2=ethylene; C3=propylene; H2=hydrogen

Table 2 reports the features of the compositons of exmaple 1

* calculated

Abrasion test, according to ISO 15527:2007, has been measure on compression molded plaque at 250°C, produced with polymers of example 1 and comparative example 2. The results are reported on table 3

Table 3

Comparative example 2 Is LP UHM 5000 an ultra-high molecular weight polyethylene designed to have an high abrasion resistance.

Claims

1. A polyolefin composition comprising:

2. The polyolefin composition according to claim 1 wherein the content of ethylene derived units, measured by NMR, in component A) ranges from 3.5 wt% and 5.5 wt%.

3. The polyolefin composition according to any of claims 1-2 wherein component A) ranges from 57 wt% to 77 wt%, and component B) ranges from 23 wt% to 43 wt%.

4. The polyolefin composition according to any of claims 1 -4 wherein the content of ethylene derived units, measured by NMR, in component B) ranges from 45 wt% to 58 wt%.

5. The polyolefin composition according to any of claims 1-5 wherein the content of ethylene derived units, measured by NMR, is comprised between 15.0 wt% and 30 wt%.

6. The polyolefin composition according to any of claims 1-5 wherein the content of ethylene derived units, measured by NMR, is comprised between 5.3 wt% and 7.2 wt%.

7. The polyolefin composition according to any of claims 1-6 wherein the content of ethylene derived units, measured by NMR, in the fraction soluble in xylene at 25°C is comprised between 38.0 wt% and 51.0 wt%.

8. The polyolefin composition according to any of claims 1-7 wherein the melt flow rate (ISO 1133 (230° C, 21.6 kg) ranges from 0.5 g/lOmin to 2.5 g/10 min.

9. The polyolefin composition according to any of claims 1-8 wherein the xylene solubles at 25°C ranges from 28 wt% to 40.0wt%;.

10. The polyolefin composition according to any of claims 1-9 wherein the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the fraction soluble in xylene at 25°C ranges from 7.9 dl/g to 13.0 dl/g.

11. The polyolefin composition according to any of claims 1-10 wherein the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the whole composition ranges from 7.9 dl/g to 13.0 dl/g.

12 The polyolefin composition according to any of claims 1-11 wherein the intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of the fraction insoluble in xylene at 25°C ranges from 6.5 dl/g to 11.3 dl/g.

13 The polyolefin composition according to any of claims 1-12 wherein the content of ethylene derived units, measured by NMR, of the fraction insoluble in xylene at 25°C is comprised between 8.3 wt% and 17.3 wt%.

14 Molded article comprising the polyolefin composition according to any of claims 1-13.

15 Compression molded article comprising the polyolefin composition according to any of claims 1-13.