WO2020113461A1

WO2020113461A1 - Composition suitable for bumpers

Info

Publication number: WO2020113461A1
Application number: PCT/CN2018/119341
Authority: WO
Inventors: Ben Chen; Jenny PAN; Henry ZHOU; Shengquan ZHU; Rongcai HUANG
Original assignee: Borouge Compounding Shanghai Co., Ltd.
Priority date: 2018-12-05
Filing date: 2018-12-05
Publication date: 2020-06-11
Also published as: CN113166506B; CN113166506A

Abstract

Composition comprising a) 40 to 70 wt. -%, preferably 40 to 60 wt. -% of a first heterphasic polypropylene HECO-PP1 having a MFR of 90 -120 g/10min (ISO1133, 230℃/2.16kg), d) 10 to 30 wt. -%, preferably 12 to 20 wt. -% of an elastomer copolymer derived from of ethylene and at least one of C4～C12 alpha olefins, having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg), and e) 10 to 30 wt. -%, preferably 16 to 22 wt. -% inorganic filler, preferably talc, whereby said composition preferably has an MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min.

Description

Composition suitable for bumpers

Field of the Invention

This invention concerns specific polypropylene compounds suitable for automotive applications, specifically bumpers.

Background

PP compounds are widely used for automotive interior and exterior application such as door panel, instrument panel and bumper due to its excellent property and easy to process. Due to less petrochemical consumption and less CO ₂ emission requirement, automotive OEMs require to decrease part weight to achieve the light-weight target. For bumper system, a way to achieve light-weight target is to reduce thickness of the bumper, i.e. a thin-wall bumper. Generally, a regular bumper has a thickness of 2.8mm in the market, and a thin-wall bumper requires a thickness of 2.3mm -2.5mm.

For thin-wall bumpers, stiffness of PP compounds have to be improved to makeup stiffness loss due to the thickness reduction. Furthermore, the thinner the wall thickness, the faster the cooling rate and solidifying of melt is in mold tunnel. So a higher flowability of compounds is required to prepare a thin-wall bumper. Compounds flowability should be increased high enough to fill the mold completely and quickly. Unfortunately a higher flowability will go hand in hand with limited mechanical properties. Thus, for thin-wall bumpers, there is a multidimensional conflict of aims, namely having higher melt flow for adequate solidification and further high stiffness as well as high impact properties.

The present invention is based on the finding, an outstanding balance of stiffness, flowability and mechanical properties can be achieved by a composition obtainable by a specific blend.

Summary of the invention

The present invention insofar provides

Composition comprising

a) 40 to 70 wt. -%, preferably 40 to 60 wt. -%of a first heterphasic polypropylene HECO-PP1 having a MFR of 90 -120 g/10min (ISO1133, 230℃/2.16kg) ,

d) 10 to 30 wt. -%, preferably 12 to 20 wt. -%of an elastomer copolymer derived from of ethylene and at least one of C4～C12 alpha olefins, having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg) , and

e) 10 to 30 wt. -%, preferably 16 to 22 wt. -%inorganic filler, preferably talc, whereby said preferably has an MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min, preferably 30 to 45 g/10min.

Particularly the present invention provides such composition, whereby said composition has an MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min and is obtainable by extruding

a) 40 to 60 wt. -%of a first heterphasic polypropylene HECO-PP1 having a MFR of 90 -120 g/10min (ISO1133, 230℃/2.16kg) ,

b) 0 to 25 wt. -%of a second heterphasic polypropylene HECO-PP2 having a MFR of 10 -30 g/10min (ISO1133, 230℃/2.16kg) ,

c) 0 to 11 wt. -%of a propylene homopolymer (Homo-PP) having a MFR of 1-100 g/10min (ISO1133, 230℃/2.16kg) ,

d) 12 to 20 wt. -%elastomer copolymer derived from of ethylene and at least one of C4～C12 alpha olefins, having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg)

e) 16 to 22 wt. -%talc,

f) 0 to 3 wt-%of carrier polymer;

g) 0 to 3 wt. -%additives, optionally selected from the group of antioxidant, UV-stabilizer, anti-scratch agent, mold release agent, and/or acid-scaverage agent;

h) 0 to 5 wt. -%color master batch (es) , whereby the components a) to h) add up to 100 wt. -%.

The present invention further provides a process for producing a composition having a MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min, the process comprising the steps of

I) providing a twin screw extruder having a first and a second side feeder, and a main feeder;

II) providing raw materials a) to h) :

e) 16 to 22 wt. -%talc,

f) 0 to 3 wt-%of polypropylene homo-and/or copolymer as carrier for additives;

h) 0 to 5 wt. -%color master batch (es) , whereby the components a) to h) add up to 100 wt. -%;

the process further comprising the step of extrusion wherein

III) component f) is premixed in an amount of up to 3 wt. -%with one or more of additives g) , whereby component f) is used in the form of a powder yielding a first premixture

IV) feeding the first premixture into a first side feeder of the twin-screw extruder,

V) feeding components a) , b) if present, c) if present and component d) into the main feeder of said twin-screw extruder,

VI) feeding talc into a further side feeder of said twin-screw extruder. thereby heating and mixing the mixture within a temperature of 100 to 250℃.

In a further aspect, the present invention is concerned with an injection-molded article comprising, preferably consisting of the inventive composition.

In a further aspect, the present invention is concerned with use of a composition comprising:

e) 10 to 30 wt. -%, preferably 16 to 22 wt. -%inorganic filler, preferably talc, whereby said composition preferably has an MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min.

for preparing bumpers having a thickness of 2.5 mm or lower.

In yet a further aspect, the present invention is concerned with the use of a composition having a MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min obtainable by extruding

e) 16 to 22 wt. -%talc,

f) 0 to 3 wt-%of carrier polymers;

for preparing bumpers having a thickness of 2.5 mm or lower.

Heterophasic polypropylenes denote polypropylenes having more than one phase, i.e. a matrix phase and dispersed therein an elastomer phase. Multiphase nature of heterophasic polypropylenes is easily detectable for example using glass transition point analysis according to ISO6721-7.

An elastomer copolymer is a copolymer of ethylene having elastic properties.

Carrier or carrier polymer denotes the polymeric material (s) to be used for introducing the additives into the composition. It is self-explaining a carrier polymer may also be one or more of the polymeric components present, i.e. foreseen in inventive composition. Inorganic filler denotes a filler with has a skeletal strucutre that does not include carbon atoms. Carbon black is not an inorganic filler.

A bumper is a structure attached to or integrated with the front and rear ends of a motor vehicle, to absorb impact in a minor collision and/or to optimize aerodynamics.

The inventive composition have a better flowability, flexural modulus and toughness which allows the provision of thin wall bumpers having a thickness of 2.5 mm or lower, preferably 2.3 mm or lower.

Component a) , i.e. 40 to 60 wt. -%of a first heterphasic polypropylene HECO-PP1 having a MFR of 90 -120 g/10min (ISO1133, 230℃/2.16kg) mainly ensures high flowability and basic mechanical properties.

Optional component b) , i.e. 0 to 25 wt. -%of a second heterphasic polypropylene HECO-PP2 having a MFR of 10 -30 g/10min (ISO1133, 230℃/2.16kg) moderates melt flow rate and additionally improves mechanical properties.

Optional component c) , i.e. 0 to 11 wt. -%of a propylene homopolymer (Homo-PP) having a MFR of 1-100 g/10min (ISO1133, 230℃/2.16kg) may be added for boosting stiffness.

Component d) , i.e. 12 to 20 wt. -%elastomer copolymer derived from of ethylene and at least one of C4～C12 alpha olefins, having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg) improves impact of the final composition.

Component e) , i.e. 16 to 22 wt. -%inorganic filler, preferably talc also improves stiffness.

Preferably the inorganic filler is selected from glass fibers, carbon fibers, phyllosilicate, mica, wollastonite or mixtures thereof. Even more preferably the inorganic filler is selected from the group of mica, wollastonite, kaolinite, smectite, montmorillonite and talc. The most preferred inorganic filler is talc.

Component f) i.e. 0.5 to 2 wt-%of polypropylene homo-and/or copolymer as carrier for additives ensures good dispersion of the additives.

Optional components g) i.e. 0 to 3 wt. -%additives, optionally selected from the group of antioxidant, UV-stabilizer, anti-scratch agent, mold release agent, and/or acid-scaverage agent ensure long term stability.

Optional component h) , i.e. 0 to 5 wt. -%color master batch (es) provide a good occurance.

All components a) to h) , as far as present, add up to 100 wt. -%.

The composition according to the present invention preferably has a flexural modulus (ISO178) measured on injection molded specimens of 80 x 10 x 4 mm prepared in accordance with ISO 294-1: 1996 of at least 1900 MPa, preferably 2000 MPa, more preferably 2400 MPa. The adaptation of the flexural modulus may be achieved via variation of the amount of the amout of propylene homopolymer and/or the amount of talc and/or the amount of component b) , i.e. the second heterophasic polypropylene HECO-PP2.

The composition according to the present invention preferably is obtained by using talc in the extrusion with a B. E. T of 15 to 25 m2/g (ISO9277) , more preferably 16 to 22 m2/g (ISO9277) , and most preferably 16 to 20 m2/g (ISO9277) . Higher B. E. T. of talc helps to increase stiffness of the composition.

Independent therefrom the composition according to the present invention is preferably obtained by using talc in the extrusion with a medium diameter D50 of 3.7-11.0 micrometer, more preferably 8.0 to 11.0 micrometer (ISO13320-1) , most preferably 9.0 to 11.0 micrometer (ISO13320-1) . In a further aspect, the D95 of the talc used in the extrusion preferably is 6.8 to 36.0 micrometer (ISO13320-1) , and more preferably 31.0 to 35.0 micrometer (ISO13320-1) .

In a preferred aspect, component c) , i.e. optional propylene homopolymer Homo-PP having a MFR of 1-100 g/10min (ISO1133, 230℃/2.16kg) , preferably 2-50g/10min. more preferably 3-20g/10min., and being added for boosting stiffness is present in an amount of at least 0.5 wt.-%, more preferably of at least 1.0 wt. -%with respect to the total of the composition, especially more preferably of from 0.5 wt% to 30.0 wt%, even more preferably of from 1.0 wt%to 15.0 wt%, most preferably of from 1.0wt%to 11wt%with respect to the total weight of the composition.

In addition to the ingredients, the composition according to the present invention is obtained by a preferred extrusion process contributing to the excellent balance of properties, the preferred extrusion process being characterized by the following steps:

(i) a carrier polymer or any of the present polymeric components in an amount of up to 3 wt. -%with respect to the total weight of the composition finally produced is premixed with one or more of additives g) , whereby the carrier polymer used is preferably present in the form of a powder yielding a first premixture,

(ii) feeding the first premixture into a first side feeder of a twin-screw extruder,

(iii) feeding components a) , b) if present, c) if present and component d) into the main feeder of said twin-screw extruder,

(iv) feeding talc into a further side feeder of said twin-screw extruder. thereby heating and mixing the mixture within a temperature of 100 to 250℃.

Independent therefrom or in addition to this aspect, the composition according to the present invention is preferably obtainable by an extrusion wherein the die temperature of extruder is within the range of 190 to 230℃.

In a further aspect, the composition according to present invention is preferably obtainable by an extrusion wherein the srew speed is within 500 to 640 rotations per minute.

In yet a further and preferred aspect, the composition according to the present invention is preferalby obtainable by an extrusion in a twin screw extruder having a die, wherein the barrel temperature profile increases from 100 to 220℃ in a first section in the extrusion direction and optionally decreases from the maximum temperature reached at the end of the first section to a barrel temperature within the range of 190 to 210℃ in a second section positioned downstream of the first section and upstream of the die.

The composition according to the present invention preferably includes as component d) an ethylene octene copolymer or ethylene butene copolymer, which has a density of 0.860 g/cm ³ to 0.880 g/cm ³ and/or a melt flow rate of 0.2 to 3.4 g/10min (ISO1133, 190℃/2.16kg) . More preferably component d) is an ethylene octene copolymer having a density of 0.860 g/cm ³ to 0.880 g/cm ³ and a melt flow rate of 0.2 to 3.4 g/10min (ISO1133, 190℃/2.16kg) .

As mentioned above, the present invention is also concerned with a process for producing a composition according to the present invention having a MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min. All preferred aspects and embodiments as described with relation to the composition shall also apply to the process.

Moreover, all preferred aspects and embodiments as described with relation to the composition shall also apply for the article, particularly the automotive article and specifically an article /automotive article having a thickness of below 2.8 mm, preferably below 2.6 mm, more preferably equal or below 2.5 mm.

The article according to the present invention preferably is a bumper. It is particularly preferred the bumper has a thickness of 2.5 mm or less.

In yet a further aspect, the present invention concerns the use of the composition having a MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min as described herein and being obtainable by extruding

c) 0 to 11 wt. -%of a propylene homopolymer having a MFR of 1-100 g/10min (ISO1133, 230℃/2.16kg) ,

e) 16 to 22 wt. -%talc,

f) 0 to 3 wt-%of carrier polymer;

for preparing bumpers having a thickness of 2.5 mm or lower.

Detailed description

A heterophasic propylene copolymer comprises a polypropylene as a matrix and dispersed therein an elastomeric propylene copolymer (EC) . Thus the polypropylene matrix contains (finely) dispersed inclusions being not part of the matrix and said inclusions contain the elastomeric propylene copolymer. The inclusions are for instance visible by high resolution microscopy, like electron microscopy or scanning force microscopy.

The matrix of the heterophasic propylene copolymer as well as the rubber phase of the heterophasic propylene copolymer may consist of a single polymer only or may be a mixture of two or more polymers each, preferably consist of a single polymer only

The heterophasic propylene copolymer may be produced by melt-blending and/or by reactor blending. In this regard “reactor-blending” denotes that the individual fractions of the polymers are produced in subsequent stages, in the presence of the product of the previous stage. For example, the matrix and the disperse phase of a heterophasic polypropylene may be produced in such subsequent stages.

Component a) , i.e. the first heterphasic polypropylene HECO-PP1 preferably is present in an amount of 40 to 55 wt. -%with respect to the total composition.

Heterophasic polypropylene HECO-PP1 further preferably has one or more of the following properties:

- Xylene soluble content XCS of 11 to 18 wt. -%, more preferably 12 to 16 wt. -% [23℃, ISO6427]

- units derived from ethylene content in the xylene soluble content C2 (XCS) of 20 to 45 wt.-%, preferably 30 to 42 wt. -% [IR calibrated by NMR]

- intrinsic viscosity of the xylene soluble content IV (XCS) of 1.8 to 2.6 dl/g, preferably 2.1 to 2.4 dl/g [decalin 135℃, DIN ISO1628/1]

- units derived from ethylene in the total HECO-PP1, i.e. C2 (total) in the range of 3.0 to 12.0 wt. -%, preferably 5.0 to 10.0 wt. -% [IR calibrated by NMR]

Component b) , i.e. the second heterophasic polypropylene HECO-PP2 preferably is present in an amount of 3 to 20 wt%, more preferably 5 to 15 wt. -%with respect to the total weight of the composition.

Heterophasic polypropylene HECO-PP2 further preferably has one or more of the following properties:

- Xylene soluble content XCS of 10 to 25 wt. -%, more preferably 13 to 22 wt. -% [23℃, ISO6427]

- units derived from ethylene content in the xylene soluble content C2 (XCS) of 20 to 45 wt.-%, preferably 30 to 40 wt. -% [IR calibrated by NMR]

- intrinsic viscosity of the xylene soluble content IV (XCS) of 2.2 to 2.9 dl/g, preferably 2.4 to 2.8 dl/g [decalin 135℃, DIN ISO1628/1]

- units derived from ethylene in the total HECO-PP1, i.e. C2 (total) in the range of 5.0 to 12 wt. -%, preferably 6.0 to 9.0 wt. -% [IR calibrated by NMR]

HECO-PP1 and HECO-PP2 differ in at least one aspect. Preferably HECO-PP1 and HECO-PP2 will differ as to their melt flow rate.

It is further preferred one or more of the following relations are fulfilled:

MFR of HECO-PP1 (ISO1133, 230℃/2.16kg) is higher than, and preferably is at least two times MFR of HECO-PP2 (ISO1133, 230℃/2.16kg) , more preferably at least three times MFR of HECO-PP2,

and/or

flexural modulus of HECO-PP1 (ISO178) is higher than flexural modulus of HECO-PP2

and/or

xylene soluble content XCS of HECO-PP1 is lower than xylene soluble content XCS of HECO-PP2.

and/or

intrinsic viscosity of the xylene soluble content IV (XCS) of HECO-PP1 (decalin 135℃, DIN ISO1628/1) is lower than the intrinsic viscosity of the xylene soluble content IV (XCS) of HECO-PP2 (decalin 135℃, DIN ISO1628/1) .

It is further highly appreciated that component c) , i.e. the propylene homopolymer having a MFR of 1-100 g/10min (ISO1133, 230℃/2.16kg) , differs from the matrix polymers of HECO-PP1 and further differ from the matrix polymer of HECO-PP2 in at least one aspect. Preferably component c) , i.e. the propylene homopolymer having a MFR of 1-100 g/10min (ISO1133, 230℃/2.16kg) , will differ from the matrix of HECO-PP1 and also will differ from the matrix of HECO-PP2 by a lower melt flow rate, which helps to increase stiffness of the composition.

HECO-PP1 can have a propylene homopolymer as matrix or a random propylene copolymer as matrix. Independent therefrom, HECO-PP2 can have a propylene homopolymer as matrix or a random propylene copolymer as matrix. A homopolymer matrix is preferred for HECO-PP1. A homopolymer matrix is preferred for HECO-PP2. More preferably both matrix components of HECO-PP1 and HECO-PP2 are homopolymers. If a random propylene copolymer is used as matrix, it should preferably not have a comonomer content of above 5.0 wt. -%.

It should be understood the mixing of two different heterophasic polymers namely HECO-PP1 and HECO-PP2 with unimodal matrix each and with unimodal rubber component results in a final material having bimodality as to the matrix component and further bimodality as to the rubber component. If additionally component c) , i.e. the propylene homopolymer as specified herein is added, it is additionally possible to have a trimodality as to the matrix component under the proviso the propylene homopolymer is unimodal.

Component c) , i.e. the propylene homopolymer preferably has a melt flow rate MFR2 (230 ℃, 2.16 kg) measured according to ISO 1133 of not more than 50 g/10 min, preferably in the range of 1 to 30 g/10 min, still more preferably in the range of 2 to 15 g/10 min. The melting temperature T _m of Component c) , i.e. the propylene homopolymer is preferably in the range of 150 to 170 ℃, like in the range of 155 to 170 ℃.

The amount of component c) , i.e. the propylene homopolymer (Homo-PP) is preferably in the range of 0.5 to 30.0 wt. -%, more preferably of from 1.0 to 15.0wt. -%based on the total weight of the total composition according to the present invention.

As outlined above, the expression propylene homopolymer as used throughout the instant invention relates to a polypropylene that consists substantially, i.e. of equal or more than 99.9 wt.-%, of propylene units. In a preferred embodiment only propylene units in the propylene homopolymer are detectable.

Component c) , i.e. the propylene homopolymer (Homo-PP) is preferably isotactic. Accordingly, it is appreciated that the propylene homopolymer (Homo-PP) has a rather high pentad concentration, i.e. higher than 80 %, more preferably higher than 85 %, yet more preferably higher than 90 %, still more preferably higher than 92 %, still yet more preferably higher than 93 %, like higher than 95 %.

Color master batch (es) can be present in amounts of 0.1 to 5 wt. -%and preferably are present in amounts of 0.1 to 2.0 wt. -%most preferably 0.1 to 1.0 wt. -%. Color master batch (es) allow the introduction of pigments. The most conventional and preferred pigment is carbon black.

In the following two particularly preferred embodiments are described.

In a first particularly preferred embodiment, the composition having a MFR (ISO1133, 230℃/2.16kg) of 30 to 45 g/10min is obtainable by extruding

a) 40 to 55 wt. -%of a first heterphasic polypropylene HECO-PP1 having a MFR of 90 -120 g/10min (ISO1133, 230℃/2.16kg) ,

b) 0 to 15 wt. -%of a second heterphasic polypropylene HECO-PP2 having a MFR of 10 -30 g/10min (ISO1133, 230℃/2.16kg) ,

c) 0 to 11 wt. -%of a propylene homopolymer having a MFR of 1-20 g/10min (ISO1133, 230℃/2.16kg) ,

d) 12 to 20 wt. -%elastomer copolymer derived from of ethylene and 1-octene, having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg) and a density of 860 to 875 kg/m ³

e) 16 to 22 wt. -%talc,

f) 0.5 to 2 wt-%of polypropylene homo-and/or copolymer as carrier for additives;

In a second particularly preferred embodiment the composition having a MFR (ISO1133, 230℃/2.16kg) of 30 to 45 g/10min is obtainable by extruding

e) 16 to 22 wt. -%talc, whereby the talc

used in the extrusion has a B. E. T of 15 to 25 m2/g (ISO9277) ,

and/or

a medium diameter D50 of 8.0 to 11.0 micrometer (ISO13320-1)

and/or

a D95 of 31.0 to 35.0 micrometer (ISO13320-1) ;

The two embodiments may be combined with any of the preferred aspects as discussed in the summary of the invention as far as appropriate.

In the following the preparation of HECO-PP1 and HECO-PP2 shall be described.

HECO-PP1

The heterophasic polypropylene (HECO-PP1) according to this invention is preferably produced in a multistage process known in the art, wherein the matrix is produced at least in one slurry reactor and subsequently the elastomeric copolymer is produced at least in one gas phase reactor. Thus, the polymerization system can comprise one or more conventional stirred slurry reactors and/or one or more gas phase reactors. Preferably the reactors used are selected from the group of loop and gas phase reactors and, in particular, the process employs at least one loop reactor and at least one gas phase reactor. It is also possible to use several reactors of each type, e.g. one loop and two or three gas phase reactors, or two loops and one or two gas phase reactors, in series. Preferably the process comprises also a prepolymerisation with the chosen catalyst system, as described in detail below, comprising the Ziegler-Natta procatalyst, the external donor and the cocatalyst. In a preferred embodiment, the prepolymerisation is conducted as bulk slurry polymerization in liquid propylene, i.e. the liquid phase mainly comprises propylene, with minor amount of other reactants and optionally inert components dissolved therein. The prepolymerisation reaction is typically conducted at a temperature of 0 to 50 ℃, preferably from 10 to 45 ℃, and more preferably from 15 to 40 ℃. The pressure in the prepolymerisation reactor is not critical but must be sufficiently high to maintain the reaction mixture in liquid phase. Thus, the pressure may be from 20 to 100 bar, for example 30 to 70 bar. The catalyst components are preferably all introduced to the prepolymerisation step. However, where the solid catalyst component (i) and the cocatalyst (ii) can be fed separately it is possible that only a part of the cocatalyst is introduced into the prepolymerisation stage and the remaining part into subsequent polymerization stages. Also in such cases it is necessary to introduce so much cocatalyst into the prepolymerisation stage that a sufficient polymerization reaction is obtained therein. It is possible to add other components also to the prepolymerization stage. Thus, hydrogen may be added into the prepolymerization stage to control the molecular weight of the prepolymer as is known in the art. Further, antistatic additive may be used to prevent the particles from adhering to each other or to the walls of the reactor. The precise control of the prepolymerization conditions and reaction parameters is within the skill of the art.

A slurry reactor designates any reactor, such as a continuous or simple batch stirred tank reactor or loop reactor, operating in bulk or slurry and in which the polymer forms in particulate form. "Bulk" means a polymerization in reaction medium that comprises at least 60 wt. -%monomer. According to a preferred embodiment the slurry reactor comprises a bulk loop reactor. "Gas phase reactor" means any mechanically mixed or fluid bed reactor. Preferably the gas phase reactor comprises a mechanically agitated fluid bed reactor with gas velocities of at least 0.2 m/sec.

The particularly preferred embodiment for the preparation of the heterophasic polypropylene (HECO-PP1) of the invention comprises carrying out the polymerization in a process comprising either a combination of one loop and one or two gas phase reactors or a combination of two loops and one or two gas phase reactors. A preferred multistage process is a slurry-gas phase process, such as developed by Borealis and known as the

technology. In this respect, reference is made to EP 0 887 379 A1, WO 92/12182, WO 2004/000899, WO 2004/111095, WO 99/24478, WO 99/24479 and WO 00/68315. They are incorporated herein by reference. A further suitable slurry-gas phase process is the

process of Basell.

Preferably the heterophasic polypropylene (HECO-PP1) according to this invention are produced by using a special Ziegler-Natta procatalyst in combination with a special external donor, as described below in detail, preferably in the

or in the

-PP process. One preferred multistage process may therefore comprise the steps of:

- producing a polypropylene matrix in the presence of the chosen catalyst system, as for instance described in detail below, comprising the special Ziegler-Natta procatalyst (i) , an external donor (iii) and the cocatalyst (ii) in a first slurry reactor and optionally in a second slurry reactor, both slurry reactors using the same polymerization conditions,

- transferring the slurry reactor product into at least one first gas phase reactor, like one gas phase reactor or a first and a second gas phase reactor connected in series,

- producing an elastomeric copolymer in the presence of the polypropylene matrix and in the presence of the catalyst system in said at least first gas phase reactor,

- recovering the polymer product for further processing.

With respect to the above-mentioned preferred slurry-gas phase process, the following general information can be provided with respect to the process conditions.

Temperature is preferably from 40 to 110 ℃, preferably between 50 and 100 ℃, in particular between 60 and 90 ℃, with a pressure in the range of from 20 to 80 bar, preferably 30 to 60 bar, with the option of adding hydrogen in order to control the molecular weight in a manner known per se. The reaction product of the slurry polymerization, which preferably is carried out in a loop reactor, is then transferred to the subsequent gas phase reactor (s) , wherein the temperature preferably is within the range of from 50 to 130 ℃, more preferably 60 to 100 ℃, at a pressure in the range of from 5 to 50 bar, preferably 8 to 35 bar, again with the option of adding hydrogen in order to control the molecular weight in a manner known per se. The average residence time can vary in the reactor zones identified above. In one embodiment, the average residence time in the slurry reactor, for example a loop reactor, is in the range of from 0.5 to 5 hours, for example 0.5 to 2 hours, while the average residence time in the gas phase reactor generally will be from 1 to 8 hours. If desired, the polymerization may be effected in a known manner under supercritical conditions in the slurry, preferably loop reactor, and/or as a condensed mode in the gas phase reactor.

According to the invention the heterophasic polypropylenes are preferably obtained by a multistage polymerization process, as described above, in the presence of a catalyst system comprising as component (i) a Ziegler-Natta procatalyst which contains a trans-esterification product of a lower alcohol and a phthalic ester.

The procatalyst used according to the invention is prepared by

a) reacting a spray crystallized or emulsion solidified adduct of MgCl ₂ and a C ₁-C ₂ alcohol with TiCl ₄

b) reacting the product of stage a) with a dialkylphthalate of formula (I)

wherein R ^1’and R ^2’are independently at least a C ₅ alkyl

under conditions where a transesterification between said C ₁ to C ₂ alcohol and said

dialkylphthalate of formula (I) takes place to form the internal donor

c) washing the product of stage b) or

d) optionally reacting the product of step c) with additional TiCl _4.

The procatalyst is produced as defined for example in the patent applications WO 87/07620, WO 92/19653, WO 92/19658 and EP 0 491 566. The content of these documents is herein included by reference.

First an adduct of MgCl ₂ and a C ₁-C ₂ alcohol of the formula MgCl ₂*nROH, wherein R is methyl or ethyl and n is 1 to 6, is formed. Ethanol is preferably used as alcohol. The adduct, which is first melted and then spray crystallized or emulsion solidified, is used as catalyst carrier. In the next step the spray crystallized or emulsion solidified adduct of the formula MgCl ₂*nROH, wherein R is methyl or ethyl, preferably ethyl and n is 1 to 6, is contacting with TiCl ₄ to form a titanised carrier, followed by the steps of

· adding to said titanised carrier

(i) a dialkylphthalate of formula (I) with R ^1’and R ^2’being independently at least a C ₅-alkyl, like at least a C ₈-alkyl,

or preferably

(ii) a dialkylphthalate of formula (I) with R ^1’and R ^2’being the same and being at least a C ₅-alkyl, like at least a C ₈-alkyl,

or more preferably

(iii) a dialkylphthalate of formula (I) selected from the group consisting of propylhexylphthalate (PrHP) , dioctylphthalate (DOP) , di-iso-decylphthalate (DIDP) , and ditridecylphthalate (DTDP) , yet more preferably the dialkylphthalate of formula (I) is a dioctylphthalate (DOP) , like di-iso-octylphthalate or diethylhexylphthalate, in particular diethylhexylphthalate,

to form a first product,

· subjecting said first product to suitable transesterification conditions, i.e. to a temperature above 100 ℃, preferably between 100 to 150 ℃, more preferably between 130 to 150 ℃, such that said methanol or ethanol is transesterified with said ester groups of said dialkylphthalate of formula (I) to form preferably at least 80 mol-%, more preferably 90 mol-%, most preferably 95 mol. -%, of a dialkylphthalate of formula (II)

with R ¹ and R ² being methyl or ethyl, preferably ethyl,

the dialkylphthalat of formula (II) being the internal donor and

· recovering said transesterification product as the procatalyst composition (component (i) ) .

The adduct of the formula MgCl ₂*nROH, wherein R is methyl or ethyl and n is 1 to 6, is in a preferred embodiment melted and then the melt is preferably injected by a gas into a cooled solvent or a cooled gas, whereby the adduct is crystallized into a morphologically advantageous form, as for example described in WO 87/07620. This crystallized adduct is preferably used as the catalyst carrier and reacted to the procatalyst useful in the present invention as described in WO 92/19658 and WO 92/19653. As the catalyst residue is removed by extracting, an adduct of the titanised carrier and the internal donor is obtained, in which the group deriving from the ester alcohol has changed. In case sufficient titanium remains on the carrier, it will act as an active element of the procatalyst. Otherwise the titanization is repeated after the above treatment in order to ensure a sufficient titanium concentration and thus activity. Preferably the procatalyst used according to the invention contains 2.5 wt. -%of titanium at the most, preferably 2.2%wt. -%at the most and more preferably 2.0 wt. -%at the most. Its donor content is preferably between 4 to 12 wt. -%and more preferably between 6 and 10 wt. -%. More preferably the procatalyst used according to the invention has been produced by using ethanol as the alcohol and dioctylphthalate (DOP) as dialkylphthalate of formula (I) , yielding diethyl phthalate (DEP) as the internal donor compound.

In a further, preferred, embodiment, the Ziegler-Natta procatalyst can be modified by polymerising a vinyl compound in the presence of the catalyst system, comprising the special Ziegler-Natta procatalyst, an external donor and a cocatalyst, which vinyl compound has the formula:

CH ₂=CH-CHR ³R ⁴

wherein R ³ and R ⁴ together form a 5-or 6-membered saturated, unsaturated or aromatic ring or independently represent an alkyl group comprising 1 to 4 carbon atoms, and the modified catalyst is used for the preparation of the heterophasic polypropylene composition according to this invention. The polymerized vinyl compound can act as an alpha-nucleating agent. This modification is in particular used for the preparation of the heterophasic polypropylene (H-PP1) . Concerning the modification of catalyst reference is made to the international applications WO 99/24478, WO 99/24479 and particularly WO 00/68315, incorporated herein by reference with respect to the reaction conditions concerning the modification of the catalyst as well as with respect to the polymerization reaction. For the production of the heterophasic polypropylenes according to the invention, the catalyst system used preferably comprises in addition to the special Ziegler-Natta procatalyst an organometallic cocatalyst as component (ii) . Accordingly, it is preferred to select the cocatalyst from the group consisting of trialkylaluminium, like triethylaluminium (TEA) , dialkyl aluminium chloride and alkyl aluminium sesquichloride. Component (iii) of the catalysts system used is an external donor represented by formula (IIIa) or (IIIb) . Formula (IIIa) is defined by

Si (OCH ₃) ₂R ₂ ⁵ (IIIa)

wherein R ⁵ represents a branched-alkyl group having 3 to 12 carbon atoms, preferably a branched-alkyl group having 3 to 6 carbon atoms, or a cyclo-alkyl having 4 to 12 carbon atoms, preferably a cyclo-alkyl having 5 to 8 carbon atoms.

It is in particular preferred that R ⁵ is selected from the group consisting of iso-propyl, iso-butyl, iso-pentyl, tert. -butyl, tert. -amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

Formula (IIIb) is defined by

Si (OCH ₂CH ₃) ₃ (NR ^xR ^y) (IIIb)

wherein R ^x and R ^y can be the same or different a represent a hydrocarbon group having 1 to 12 carbon atoms.

R ^x and R ^y are independently selected from the group consisting of linear aliphatic hydrocarbon group having 1 to 12 carbon atoms, branched aliphatic hydrocarbon group having 1 to 12 carbon atoms and cyclic aliphatic hydrocarbon group having 1 to 12 carbon atoms. It is in particular preferred that R ^x and R ^y are independently selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decanyl, iso-propyl, iso-butyl, iso-pentyl, tert. -butyl, tert. -amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl. More preferably both R ^x and R ^y are the same, yet more preferably both R ^x and R ^y are an ethyl group.

Most preferably the external donor is of formula (IIIa) , like dicyclopentyl dimethoxy silane [Si (OCH ₃) ₂ (cyclo-pentyl) ₂] or diisopropyl dimethoxy silane [Si (OCH ₃) ₂ (CH (CH ₃) ₂) ₂] .

HECO-PP2 preparation

The heterophasic propylene copolymer according to the present invention is preferably produced in a sequential polymerization process, i.e. in a multistage process, known in the art, as described above.

Accordingly it is preferred that the heterophasic propylene copolymer is produced in a sequential polymerization process comprising the steps of

(a) polymerizing propylene and optionally at least one ethylene and/or C ₄ to C ₁₂ α-olefin in a first reactor (R1) obtaining the first polypropylene fraction of the polypropylene (PP-1) , preferably said first polypropylene fraction is a first propylene homopolymer,

(b) transferring the first polypropylene fraction into a second reactor (R2) ,

(c) polymerizing in the second reactor (R2) and in the presence of said first polypropylene fraction propylene and optionally at least one ethylene and/or C ₄ to C ₁₂ α-olefin obtaining thereby the second polypropylene fraction, preferably said second polypropylene fraction is a second propylene homopolymer, said first polypropylene fraction and said second polypropylene fraction form the polypropylene (PP-1) , like the propylene homopolymer (PP-1) , i.e. the matrix of the heterophasic propylene copolymer (HECO-PP2) ,

(d) transferring the polypropylene (PP-1) of step (c) into a third reactor (R3) ,

(e) polymerizing in the third reactor (R3) and in the presence of the polypropylene (PP-1) obtained in step (c) propylene and at least one of ethylene and/or C ₄ to C ₁₂ α-olefin obtaining thereby a first elastomeric propylene copolymer fraction, the first elastomeric propylene copolymer fraction is dispersed in the polypropylene (PP-1) ,

(f) transferring the polypropylene (PP-1) in which the first elastomeric propylene copolymer fraction is dispersed into a fourth reactor (R4) , and

(g) polymerizing in the fourth reactor (R4) and in the presence of the mixture obtained in step (e) propylene and at least one of ethylene and/or C ₄ to C ₁₂ α-olefin obtaining thereby the second elastomeric propylene copolymer fraction, the polypropylene (PP-1) , the first elastomeric propylene copolymer fraction, and the second elastomeric propylene copolymer fraction form the heterophasic propylene copolymer (HECO-PP2) .

Alternatively the elastomeric propylene copolymer (E-1) can be also produced in one gas phase reactor, i.e. the fourth reactor (R4) is optional.

Of course, in the first reactor (R1) the second polypropylene fraction can be produced and in the second reactor (R2) the first polypropylene fraction can be obtained. The same holds true for the elastomeric propylene copolymer phase. Accordingly in the third reactor (R3) the second elastomeric propylene copolymer fraction can be produced whereas in the fourth reactor (R4) the first elastomeric propylene copolymer fraction is made.

Preferably between the second reactor (R2) and the third reactor (R3) and optionally between the third reactor (R3) and fourth reactor (R4) the monomers are flashed out.

The term “sequential polymerization process” indicates that the heterophasic propylene copolymer (HECO-PP2) is produced in at least two, like three or four reactors connected in series. Accordingly the present process comprises at least a first reactor (R1) and a second reactor (R2) , more preferably a first reactor (R1) , a second reactor (R2) , a third reactor (R3) and a fourth reactor (R4) , and more preferably a first reactor (R1) , a second reactor (R2) , and a third reactor (R3) . The term “polymerization reactor” shall indicate that the main polymerization takes place. Thus in case the process consists of four or three polymerization reactors, this definition does not exclude the option that the overall process comprises for instance a pre-polymerization step in a pre-polymerization reactor. The term “consist of” is only a closing formulation in view of the main polymerization reactors.

The first reactor (R1) is preferably a slurry reactor (SR) and can be any continuous or simple stirred batch tank reactor or loop reactor operating in bulk or slurry. Bulk means a polymerization in a reaction medium that comprises of at least 60 % (w/w) monomer.

According to the present invention the slurry reactor (SR) is preferably a (bulk) loop reactor (LR) . The second reactor (R2) , the third reactor (R3) and the fourth reactor (R4) are preferably gas phase reactors (GPR) . Such gas phase reactors (GPR) can be any mechanically mixed or fluid bed reactors. Preferably the gas phase reactors (GPR) comprise a mechanically agitated fluid bed reactor with gas velocities of at least 0.2 m/sec. Thus it is appreciated that the gas phase reactor is a fluidized bed type reactor preferably with a mechanical stirrer.

Thus in a preferred embodiment the first reactor (R1) is a slurry reactor (SR) , like a loop reactor (LR) , whereas the second reactor (R2) , the third reactor (R3) and the fourth reactor (R4) are gas phase reactors (GPR) . Accordingly for the instant process at least three, preferably three polymerization reactors, namely a slurry reactor (SR) , like a loop reactor (LR) , a first gas phase reactor (GPR-1) , and a second gas phase reactor (GPR-2) connected in series are used. If needed prior to the slurry reactor (SR) a pre-polymerization reactor is placed.

As regards the general process setup reference is made to the aforesaid.

Preferably, in the instant process for producing the heterophasic propylene copolymer (HECO-PP2) as defined above the conditions for the first reactor (R1) , i.e. the slurry reactor (SR) , like a loop reactor (LR) , of step (a) may be as follows:

- the temperature is within the range of 50 ℃ to 110 ℃, preferably between 60 ℃ and 100 ℃, more preferably between 68 and 95 ℃,

- the pressure is within the range of 20 bar to 80 bar, preferably between 40 bar to 70 bar,

- hydrogen can be added for controlling the molar mass in a manner known per se.

Subsequently, the reaction mixture from step (a) is transferred to the second reactor (R2) , i.e. gas phase reactor (GPR-1) , i.e. to step (c) , whereby the conditions in step (c) are preferably as follows:

- the temperature is within the range of 50 ℃ to 130 ℃, preferably between 60 ℃ and 100 ℃,

- the pressure is within the range of 5 bar to 50 bar, preferably between 15 bar to 35 bar,

The condition in the third reactor (R3) and the fourth reactor (R4) , preferably in the second gas phase reactor (GPR-2) and third gas phase reactor (GPR-3) , is similar to the second reactor (R2) .

The residence time can vary in the three reactor zones.

In one embodiment of the process for producing the polypropylene the residence time in bulk reactor, e.g. loop is in the range 0.1 to 2.5 hours, e.g. 0.15 to 1.5 hours and the residence time in gas phase reactor will generally be 0.2 to 6.0 hours, like 0.5 to 4.0 hours.

If desired, the polymerization may be effected in a known manner under supercritical conditions in the first reactor (R1) , i.e. in the slurry reactor (SR) , like in the loop reactor (LR) , and/or as a condensed mode in the gas phase reactors (GPR) .

Preferably the process comprises also a prepolymerization with the catalyst system, as described in detail above, comprising a Ziegler-Natta procatalyst, an external donor and optionally a cocatalyst. Reference is again made to the aforesaid.

The catalyst components are preferably all introduced to the prepolymerization step. However, where the solid catalyst component (i) and the cocatalyst (ii) can be fed separately it is possible that only a part of the cocatalyst is introduced into the prepolymerization stage and the remaining part into subsequent polymerization stages. Also in such cases it is necessary to introduce so much cocatalyst into the prepolymerization stage that a sufficient polymerization reaction is obtained therein. It is possible to add other components also to the prepolymerization stage. Thus, hydrogen may be added into the prepolymerization stage to control the molecular weight of the prepolymer as is known in the art. Further, antistatic additive may be used to prevent the particles from adhering to each other or to the walls of the reactor.

According to the present invention the heterophasic propylene copolymer (HECO-PP2) is obtained by a multistage polymerization process, as described above, in the presence of a catalyst system comprising as component (i) a Ziegler-Natta procatalyst which contains a trans-esterification product of a lower alcohol and a phthalic ester.

As regards the preparition of the procatalyst reference is made to the aforesaid.

It is appreciated that the heterophasic propylene copolymer (HECO-PP2) is α-nucleated. In case the α-nucleation is not effected by a vinylcycloalkane polymer or a vinylalkane polymer as indicated above, the following α-nucleating agents may be present

(i) salts of monocarboxylic acids and polycarboxylic acids, e.g. sodium benzoate or aluminum tert-butylbenzoate, and

(ii) dibenzylidenesorbitol (e.g. 1, 3 : 2, 4 dibenzylidenesorbitol) and C ₁-C ₈-alkyl-substituted dibenzylidenesorbitol derivatives, such as methyldibenzylidenesorbitol, ethyldibenzylidenesorbitol or dimethyldibenzylidenesorbitol (e.g. 1, 3 : 2, 4 di(methylbenzylidene) sorbitol) , or substituted nonitol-derivatives, such as 1, 2, 3, -trideoxy-4, 6: 5, 7-bis-O- [ (4-propylphenyl) methylene] -nonitol, and

(iii) salts of diesters of phosphoric acid, e.g. sodium 2, 2'-methylenebis (4, 6, -di-tert-butylphenyl) phosphate or aluminium-hydroxy-bis [2, 2'-methylene-bis (4, 6-di-t-butylphenyl) phosphate] , and

(iv) mixtures thereof.

Component d) , i.e. 12 to 20 wt. -%of elastomer copolymer derived from of ethylene and at least one of C4～C12 alpha olefins (EEC) , having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg) shall be described in more detail in the following. The comonomers present in the elastomeric copolymer (EEC) are C ₄ to C ₁₂ α-olefins, like 1-butene, 1-hexene and 1-octene, the latter especially preferred. Accordingly in one specific embodiment the elastomeric copolymer (EEC) is an ethylene-1-butane copolymer, or ethylene-1-octene copolymer with the amounts given in this paragraph.

One important aspect of the present invention is that the amount of elastomeric copolymer (EEC) in the final composition is rather moderate. Accordingly, it is preferred that the elastomeric copolymer is preferably present in the total composition according to the present invention in an amount of between 10.0 and 25wt%, preferably 13.0 and 19.0 wt. -%, more preferably in an amount between 14.0 and 18.0 wt. -%, based on the total weight of the total polypropylene composition according to the present invention.

The elastomeric copolymer (EEC) is known in the art and belongs in a preferred embodiment to the Queo and Engage products well known in the art.

It is neeedless to say, the elastomeric copolymer (EEC) usually will be preent in dispersed form in the matrix, i.e. in the polypropylene (PP) homo-or random copolymers of the heterophasic propylene copolymers (HECOs) , by compounding.

Inorganic filler (component g)

As another essential component, the composition according to the present invention comprises inorganic filler.

The inorganic filler (F) is present in the polypropylene composition (PP) in amounts of 10 to 30 wt. -%, more preferably in the range of from 15.0 to 25.0 wt. -%, and even more preferably in the range of from 16 to 22 wt. -%, even more preferably in the range of from 17 to 22 wt. %, based on the total weight of the composition according to the present invention.

Preferably the inorganic filler is mica, wollastonite, kaolinite, smectite, calcium carbonate, montmorillonite, talc, phyllosilicate or a mixture thereof. The most preferred inorganic filler is talc.

The inorganic filler preferably has a median particle size d ₅₀ calculated from the particle size distribution in mass percent and measured by laser diffraction in the range of 0.2 to 20.0 μm, more preferably in the range of 0.3 to 15.0 μm, still more preferably in the range of 3.0 to 12.0 μm.

Additionally or alternatively, the inorganic filler has a specific surface area BET in the range from 1.0 to 50.0 m ²/g, more preferably in the range from 5.0 to 40.0 m ²/g, still more preferably in the range from 15.0 to 22.0 m ²/g and most preferably in the range of 15.0 to 20.0 m ²/g.

Propylene homopolymer (component c) )

Another optional component of the composition according to the present invention is a propylene homopolymer (Homo-PP) . The propylene homopolymer (Homo-PP) is added to the composition according to the present invention to improve the stiffness. It is appreciated that the polypropylene composition (PP) comprises the propylene homopolymer (Homo-PP) in an amount of from 0.5 to 30.0 wt. -%, preferably of from 1.0 to 15.0 wt. -%, and even more preferably of from 1.0 to 11.0 wt. -%based on the total weight of the total composition according to the present invention.

The propylene homopolymer (Homo-PP) is not a heterophasic polymer, i.e. a system comprising a crystalline matrix phase in which an elastomeric phase is dispersed. Accordingly, the propylene homopolymer (Homo-PP) as such is monophasic, i.e. in DMTA no multiphase structure can be identified as there exists just one glass transition temperature.

Further, the propylene homopolymer (Homo-PP) preferably has a melting temperature of more than 155℃, i.e. of more than 155 to 169 ℃, more preferably of at least 158℃, i.e. in the range of from 158 to 168 ℃, still more preferably in the range of from 162 to 168℃. Preferably, a further characteristic of the propylene homopolymer (Homo-PP) is the low amount of misinsertions of propylene within the polymer chain, which indicates that the propylene homopolymer (Homo-PP) is produced in the presence of a Ziegler-Natta catalyst. Accordingly the propylene homopolymer (Homo-PP) is preferably featured by low amount of 2, 1 erythro regio-defects, i.e. of equal or below 0.4 mol. -%, more preferably of equal or below than 0.2 mol. -%, like of not more than 0.1 mol. -%, determined by 13C-NMR spectroscopy. In an especially preferred embodiment no 2, 1 erythro regio-defects are detectable.

The propylene homopolymer (Homo-PP) preferably has a melt flow rate MFR2 (230℃) measured according to ISO 1133 in the range of from 2.0 to 30.0 g/10min, preferably in the range of from 2.0 to 20.0 g/10 min.

The propylene homopolymer (Homo-PP) can be chemically identical to the matrix (M) of one of the heterophasic propylene copolymers (HECO-PP1 or HECO-PP2) . In another preferred embodiment, the propylene homopolymer (homo-PP) is chemical different, preferably different in the melt flow rate, to the matrix, i.e. to the propylene homopolymer (PP-1) , of the matrix phasees of any one of both heterophasic propylene copolymers (HECO-PP1 and HECO-PP2)

In one preferred embodiment, the propylene homopolymer (Homo-PP) has a melt flow rate MFR ₂ (230℃) which is lower, preferably at least 5 g/10min lower, more preferably at least 8 g/10min lower, even more preferably 5 to 50 g/10min lower, yet more preferably 8 to 20 g/10min lower, than the matrix, i.e. the propylene homopolymer , of any one of both heterophasic propylene copolymers (HECO-PP1 and HECO-PP2) , which helps to increase stiffness of the composition.

Preparation of propylene homopolymers is known in the art. Preferably Ziegler-Natta catalysts are used.

Experimental Part

Measurement methods

Charpy notched impact strength was determined according to ISO 179 /1eA at 23 ℃ and at 0 ℃ by using injection moulded test specimens as described in EN ISO 1873-2 (80 x 10 x 4 mm) .

Flexural Modulus: The flexural modulus was determined in 3-point-bending according to ISO 178 on injection molded specimens of 80 x 10 x 4 mm prepared in accordance with ISO 294-1: 1996.

Melt Flow Rate (MFR ₂)

The melt flow rates were measured with a load of 2.16 kg (MFR ₂) , at 230 ℃ or 190℃ as set forth in ISO 1133.

Intrinsic viscosity was measured according to DIN ISO 1628/1, October 1999 (in Decalin at 135 ℃) .

Density was measured according to ISO 1183-187. Sample preparation was done by compression moulding in accordance with ISO 1872-2: 2007.

B.E. T

B.E. T was measured according to ISO9277. Brunauer–Emmett–Teller (B.E. T) applies adsorption evaluation for analysis of the surface.

NMR-spectroscopy measurements:

Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content and comonomer sequence distribution of the polymers. Quantitative ¹³C { ¹H} NMR spectra were recorded in the solution-state using a Bruker Advance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for ¹H and ¹³C respectively. All spectra were recorded using a ¹³C optimised 10 mm extended temperature probehead at 125℃ using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 3 ml of 1, 2-tetrachloroethane-d ₂ (TCE-d ₂) along with chromium- (III) -acetylacetonate (Cr (acac) ₃) resulting in a 65 mM solution of relaxation agent in solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009) , 475) . To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatary oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution and quantitatively needed for accurate ethylene content quantification. Standard single-pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128) . A total of 6144 (6k) transients were acquired per spectra. Quantitative ¹³C { ¹H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present. Characteristic signals corresponding to the incorporation of ethylene were observed Cheng, H. N., Macromolecules 17 (1984) , 1950) .

With characteristic signals corresponding to 2, 1 erythro regio defects observed (as described in L.

Resconi, L. Cavallo, A. Fait, F. Piemontesi, Chem. Rev. 2000, 100 (4) , 1253, in Cheng, H. N.,

Macromolecules 1984, 17, 1950, and in W-J. Wang and S. Zhu, Macromolecules 2000, 33 1157) the correction for the influence of the regio defects on determined properties was required. Characteristic signals corresponding to other types of regio defects were not observed.

The comonomer fraction was quantified using the method of Wang et. al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000) , 1157) through integration of multiple signals across the whole spectral region in the ¹³C { ¹H} spectra. This method was chosen for its robust nature and ability to account for the presence of regio-defects when needed. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents.

For systems where only isolated ethylene in PPEPP sequences was observed the method of Wang et. al. was modified to reduce the influence of non-zero integrals of sites that are known to not be present. This approach reduced the overestimation of ethylene content for such systems and was achieved by reduction of the number of sites used to determine the absolute ethylene content to:

E = 0.5 (Sββ + Sβγ + Sβδ + 0.5 (Sαβ + Sαγ) )

Through the use of this set of sites the corresponding integral equation becomes:

E = 0.5 (I _H +I _G + 0.5 (I _C + I _D) )

using the same notation used in the article of Wang et. al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000) , 1157) . Equations used for absolute propylene content were not modified.

The mole percent comonomer incorporation was calculated from the mole fraction:

E [mol%] = 100 *fE

The weight percent comonomer incorporation was calculated from the weight fraction:

E [wt%] = 100 * (fE *28.06) / ( (fE *28.06) + ( (1-fE) *42.08) )

The comonomer sequence distribution at the triad level was determined using the analysis method of Kakugo et al. (Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150) . This method was chosen for its robust nature and integration regions slightly adjusted to increase applicability to a wider range of comonomer contents.

Medium diameter D50 and D95

ISO13320-1 was used (laser diffraction method) .

Xylene cold soluble fraction (XCS wt%)

The xylene cold soluble fraction (XCS) is determined at 23 ℃ according to ISO 6427.

Examples

Materials

The following raw materials were used to prepare the compositions of the Examples.

Heterophasic polypropylenes as described HECO-PP1 and HECO-PP2.

Preparation of HECO-PP1:

The heterophasic propylene copolymer (HECO-1) used for inventive examples Ex. 1-3, was prepared with one slurry loop reactor and two gas phase reactors by the known

technology, as disclosed in EP 0 887 379 A1.

The catalyst used in the polymerization process for the preparation of the heterophasic propylene copolymer (HECO-1) (inventive examples Ex. 1-3) has been produced as follows:

First, 0.1 mol of MgCl ₂ x 3 EtOH was suspended under inert conditions in 250 ml of decane in a reactor at atmospheric pressure. The solution was cooled to the temperature of –15℃ and 300 ml of cold TiCl ₄ was added while maintaining the temperature at said level. Then, the temperature of the slurry was increased slowly to 20 ℃. At this temperature, 0.02 mol of dioctylphthalate (DOP) was added to the slurry. After the addition of the phthalate, the temperature was raised to 135 ℃ during 90 minutes and the slurry was allowed to stand for 60 minutes. Then, another 300 ml of TiCl ₄ was added and the temperature was kept at 135 ℃ for 120 minutes. After this, the catalyst was filtered from the liquid and washed six times with 300 ml heptane at 80 ℃. Then, the solid catalyst component was filtered and dried. Catalyst and its preparation concept is described in general e.g. in patent publications EP491566, EP591224 and EP586390. As co-catalyst triethyl-aluminium (TEAL) and as donor dicyclopentyldimethoxysilane [ (C ₅H ₉) ₂Si (OCH ₃) ₂] was used. The aluminium to donor ratio is indicated in table 1.

Table 1: Preparation and Properties of heterophasic propylene copolymers HECO-1

		HECO1
TEA/Ti	[mol/mol]	220
TEAL/Donor	[mol/mol]	10
Loop
temperature	[℃]	75
residence time	[h]	0.6
H2/C3 ratio	[mol/kmol]	22
MFR	[g/10min]	160
Split	[wt. -%]	51
GPR 1
temperature	[℃]	80
pressure	[kPa]	2200
H2/C3 ratio	[mol/kmol]	175
MFR	[g/10min]	160
XCS	[wt. -%]	2.0
Split	[wt. -%]	33
GPR 2
temperature	[℃]	80
pressure	[kPa]	2190
H2/C2 ratio	[mol/kmol]	250
C2/C3 ratio	[mol/kmol]	550
C2	[mol-%]	11
XCS	[wt. -%]	15.0
C2 (XCS)	[mol-%]	49
MFR	[g/10min]	95
Split	[wt. -%]	16
IV of XCS	[dl/g]	2.3

Preparation of HECO-PP2:

Heterophasic propylene copolymer (HECO-PP2) used for the inventive examples was prepared with one slurry loop reactor and two gas phase reactors by the known

technology, as disclosed in EP 0 887 379 A1.

The catalyst used in the polymerization process of the HECO-PP2 has been produced as follows:

First, 0.1 mol of MgCl ₂ x 3 EtOH was suspended under inert conditions in 250 ml of decane in a reactor at atmospheric pressure. The solution was cooled to the temperature of –15℃ and 300 ml of cold TiCl ₄ was added while maintaining the temperature at said level. Then, the temperature of the slurry was increased slowly to 20 ℃. At this temperature, 0.02 mol of dioctylphthalate (DOP) was added to the slurry. After the addition of the phthalate, the temperature was raised to 135 ℃ during 90 minutes and the slurry was allowed to stand for 60 minutes. Then, another 300 ml of TiCl ₄ was added and the temperature was kept at 135 ℃ for 120 minutes. After this, the catalyst was filtered from the liquid and washed six times with 300 ml heptane at 80 ℃. Then, the solid catalyst component was filtered and dried. Catalyst and its preparation concept is described e.g. in patent publications EP491566, EP591224 or EP586390. The catalyst was prepolymerized with vinyl cyclohexane in an amount to achieve a concentration of 200 ppm poly (vinyl cyclohexane) (PVCH) in the final polymer (see EP 1183307 A1) . As co-catalyst triethyl-aluminium (TEAL) and as donor dicyclo pentyl dimethoxy silane (D-donor) were used. The aluminium to donor ratio is indicated in Table 2.

Table 2: Preparation and Properties of HECO-PP2

Loop		HECO-PP2
TEAL/Ti	[mol/mol]	177
TEAL/D donor	[mol/mol]	10.3
Temperature	[℃]	80
Pressure	[bar]	55
H ₂/C ₃ ratio	[mol/kmol]	36
MFR ₂ (230 ℃)	[g/10 min]	40
XCS	[wt. -%]	1.5
Split	[wt. -%]	46
GPR 1
Temperature	[℃]	95
Pressure	[kPa]	24
H ₂/C ₃ ratio	[mol/kmol]	230
MFR ₂ (230 ℃)	[g/10 min]	40
XCS	[wt. -%]	1.4
Split	[wt. -%]	36
GPR 2 (Final)
Temperature	[℃]	85
Pressure	[kPa]	19
H ₂/C ₂ ratio	[mol/kmol]	170
C ₂/C ₃ ratio	[mol/kmol]	580
MFR ₂ (230 ℃)	[g/10 min]	20
XCS	[wt. -%]	17.5
C2 of XCS	[wt. -%]	34
IV of XCS	[dl/g]	2.6
C2 total	[wt. -%]	7.5
Split	[wt. -%]	18

copolymer of ethylene and octylene (Enagage 8100 POE, commercially available from Dow) :

- MFR: 1g/10min (190℃/2.16kg)

copolymer of ethylene and butene (Enagage 7467 POE, commercially available from Dow) :

- MFR: 1g/10min (190℃/2.16kg)

Homo-PP:

- MFR: 8g/10min (230℃/2.16kg)

- Flexural modulus: 2100 MPa

- Notched Charpy Impact at -20℃ : 6KJ/m ²

Jetfine 3CA of Imerys Co. Ltd. (France)

- Median diameter D50: 3.9μm tested by laser diffraction method

- Median diameter D95: 7.8μm tested by laser diffraction method

- B.E. T: 14.5m ²/g

HAR T84 of Imerys Co. Ltd. c (France)

- Median diameter D50: 10.5μm tested by laser diffraction method

- Median diameter D95: 34.2μm tested by laser diffraction method

- B.E. T: 19.5m ²/g

Additives: propylene homopolymer powder as carrier, Antioxidant, Mold release agent, Acid scaverage agent, and Color master batch

Irganox 1076 antioxidant: Octadecyl 3- (3’, 5’-di-tert. butyl-4-hydroxyphenyl) propionate, commercially available from BASF, T _m 50℃;

Irgafos 168 antioxidant: Tris (2, 4-di-t-butylphenyl) phosphite, commercially available from BASF, T _m 182℃; Rikemal AS-105 mold release agent: distilled monoglycerides, commercially available from Rikevita Co. Ltd. (Japan)

Preparation of the composition by compounding:

A twin screw extruder was used. The additive mixture was premixed with polypropylene powder. The additive mixture comprises antioxidant agent, mold release agent, acid scaverage agent and color master batch. The resulting premixture was fed into feeder 3 being a side feeder of the twin-screw extruder. Heco-PP, homoPP, and POE were fed into the main feeder 1 of the twin-screw extruder. Talc was fed via side feeder 2. All feed materials were heated and mixed homogeneously via extrusion at a temperature of 100-250℃.

Table 3 provides an overview.

For comparative purposes Borouge grade “EF296AEC-9502” was used. Table 4 below shows the results as comparative Example (CE) .

Table 4 Results of Ex. 1-3 and CE.

It is directly apparent, examples Ex. 1 to 3 have very good stiffness and still acceptable impact strength. Examples Ex 1 to 3 are allowed for ultrathin bumpers.

Examples Ex. 2 and 3 showed a balance of an even further improved stiffness and impact and easily allowed for preparation of bumpers having a thickness of 2.3 mm only.

Extrusion conditions as used are given in the following table 5 below.

Table 5 extrusion process parameters in extruder

Bumpers are made by injection molding.

Claims

Composition comprising

a) 40 to 70 wt. -%, preferably 40 to 60 wt. -%of a first heterphasic polypropylene HECO-PP1 having a MFR of 90 -120 g/10min (ISO1133, 230℃/2.16kg) ,

d) 10 to 30 wt. -%, preferably 12 to 20 wt. -%of an elastomer copolymer derived from of ethylene and at least one of C4～C12 alpha olefins, having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg) , and

e) 10 to 30 wt. -%, preferably 16 to 22 wt. -%inorganic filler, preferably talc, whereby said composition preferably has an MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min.
Composition according to claim 1 further comprising

b) 0 to 25 wt. -%of a second heterphasic polypropylene HECO-PP2 having a MFR of 10 -30 g/10min (ISO1133, 230℃/2.16kg) .
Composition according to claim 1 or 2 further comprising

c) 0 to 15 wt. -%, preferably 0 to 11 wt. -%of a propylene homopolymer having a MFR of 1-100 g/10min (ISO1133, 230℃/2.16kg) .
Composition according to any one of claims 1 to 3 having a MFR (ISO1133, 230℃/2.16kg) of 30 to 45 g/10min obtainable by extruding

a) 40 to 60 wt. -%of a first heterphasic polypropylene HECO-PP1 having a MFR of 90 -120 g/10min (ISO1133, 230℃/2.16kg) ,

b) 0 to 25 wt. -%of a second heterphasic polypropylene HECO-PP2 having a MFR of 10 -30 g/10min (ISO1133, 230℃/2.16kg) ,

c) 0 to 11 wt. -%of a propylene homopolymer having a MFR of 1-100 g/10min (ISO1133, 230℃/2.16kg) ,

d) 12 to 20 wt. -%elastomer copolymer derived from of ethylene and at least one of C4～C12 alpha olefins, having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg)

e) 16 to 22 wt. -%talc.
Composition according to any one of claims 1 to 3 having a MFR (ISO1133, 230℃/2.16kg) of 30 to 45 g/10min obtainable by extruding

a) 40 to 60 wt. -%of a first heterphasic polypropylene HECO-PP1 having a MFR of 90 -120 g/10min (ISO1133, 230℃/2.16kg) ,

b) 0 to 25 wt. -%of a second heterphasic polypropylene HECO-PP2 having a MFR of 10 -30 g/10min (ISO1133, 230℃/2.16kg) ,

c) 0 to 11 wt. -%of a propylene homopolymer having a MFR of 1-100 g/10min (ISO1133, 230℃/2.16kg) ,

d) 12 to 20 wt. -%elastomer copolymer derived from of ethylene and at least one of C4～C12 alpha olefins, having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg)

e) 16 to 22 wt. -%talc

f) 0 to 3 wt-%of carrier polymer;

g) 0 to 3 wt. -%additives, optionally selected from the group of antioxidant, UV-stabilizer, anti-scratch agent, mold release agent, and/or acid-scaverage agent;

h) 0 to 5 wt. -%color master batch (es) ,

whereby the components a) to h) add up to 100 wt. -%.
Composition according to any one of the preceding claims, wherein the composition has a flexural modulus (ISO178) measured on injection molded specimens of 80 x 10 x 4 mm prepared in accordance with ISO 294-1: 1996 of at least 1900 MPa, preferably 2400 MPa.
Composition according to any one of claims 4 to 6, wherein component d) is an ethylene octene copolymer.
Composition according to any one of claims 4 to 6, wherein component d) is an ethylene octene copolymer having a density of 0.860 g/cm ³ to 0.880 g/cm ³ and/or has a melt flow rate of 0.2 to 3.4 g/10min (ISO1133, 190℃/2.16kg) .
An injection-molded article comprising, preferably consisting of the composition according to any of claims 1 to 11.
The injection-molded article according to claim 9 being an automotive article, preferably a bumper, more preferably a bumper having a thickness of 2.5 mm or less.
Use of a composition comprising:

(a) 40 to 70 wt. -%, preferably 40 to 60 wt. -%of a first heterphasic polypropylene HECO-PP1 having a MFR of 90 -120 g/10min (ISO1133, 230℃/2.16kg) ,

(d) 10 to 30 wt. -%, preferably 12 to 20 wt. -%of an elastomer copolymer derived from of ethylene and at least one of C4～C12 alpha olefins, having a MFR of 0.2 to 8g/10min (ISO1133, 190℃/2.16kg) , and

(e) 10 to 30 wt. -%, preferably 16 to 22 wt. -%inorganic filler, preferably talc, whereby said composition preferably has an MFR (ISO1133, 230℃/2.16kg) of 30 to 50 g/10min.,

for preparing bumpers having a thickness of 2.5 mm or lower.