WO2021062620A1

WO2021062620A1 - Polypropylene composition for extrusion as laminating film for automotive interior articles

Info

Publication number: WO2021062620A1
Application number: PCT/CN2019/109423
Authority: WO
Inventors: Henry ZHOU; Tony Zhang; Pinlin ZHAO
Original assignee: Borouge Compounding Shanghai Co., Ltd.
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2021-04-08
Also published as: CN114555692A

Abstract

The present invention relates to a polypropylene composition comprising a propylene random copolymer and elastomeric ethylene random copolymer, films comprising said polypropylene composition and injection-moulded polypropylene articles laminated by said films.

Description

POLYPROPYLENE COMPOSITION FOR EXTRUSION AS LAMINATING FILM FOR AUTOMOTIVE INTERIOR ARTICLES

Polypropylene is one of the main polymeric materials used in the manufacture of automotive components, as a result of favourable mechanical properties, including a balance of stiffness and impact strength. Typically these automotive components are obtained through injection moulding, due to the high complexity obtainable on a large scale. Whilst polypropylene is the polymer of choice for both exterior and interior automotive components, the properties of most polypropylene grades need to be improved for injection-moulded interior articles, since the surface properties and appearance of these articles is of paramount importance. Due to the rheological properties of polypropylene, unstable flow in injection moulding can lead to defects in the surface appearance, such as tiger stripe, gloss differences, and gate blush, amongst other examples.

Whilst overcoming these drawbacks has long since been a goal in the field of polypropylene development, it may be difficult to suitably adjust rheological properties without adversely affecting the mechanical properties of the articles.

The finding of the present invention is that a polypropylene composition may be used to produce films for laminating injection-moulded polypropylene articles, avoiding the occurrence of undesired aesthetic defects without impacting the key mechanical properties of the articles.

Therefore, the present invention is directed to a polypropylene composition (PC) comprising:

a) from 60 to 90 wt. -%of a propylene random copolymer (R-PP) with propylene monomer units and one or more comonomer units selected from ethylene and/or alpha-olefins with 4 to 12 carbon atoms, wherein

i) the melt flow rate MFR ₂ (230 ℃, 2.16 kg, ISO 1133) is in the range from 0.1 to 15.0 g/10 min, and

ii) the Vicat softening temperature, method A is in the range from 110 to 140 ℃ (ISO 306) ,

b) from 5 to 35 wt. -%of an elastomeric ethylene random copolymer (E) with ethylene monomer units and one or more comonomer units selected from alpha-olefins with 4 to 12 carbon atoms,

wherein the melting temperature (ISO 11357) is at least 75 ℃,

c) from 0 to 5 wt. -%additives (A) ,

wherein the wt. -%given for each component is with respect to the total weight of the polypropylene composition, and the polypropylene composition has a melt flow rate MFR ₂ (230 ℃, 2.16 kg, ISO 1133) in the range from 1.0 to 5.0 g/10 min.

In a preferred embodiment, said propylene random copolymer (R-PP) has a content of comonomer units selected from ethylene and/or alpha-olefins with 4 to 12 carbon atoms is in the range from 2 to 5 wt. -%as determined by quantitative ¹³C-NMR spectroscopy.

In a preferred embodiment, said elastomeric ethylene random copolymer (E) has a content of comonomer units selected from alpha-olefins with 4 to 12 carbon atoms is in the range from 30 to 50 wt. -%as determined by quantitative ¹³C-NMR spectroscopy.

In a preferred embodiment the combined content of (R-PP) , (E) and (A) in the propylene composition (PC) is at least 90 wt. -%, preferably at least 95 wt. -%, most preferably the propylene composition (PC) consists of (R-PP) , (E) and (A) .

In a preferred embodiment, the ratio of the content of the propylene random copolymer (R-PP) to the content of the elastomeric ethylene random copolymer (E) in the polypropylene composition (PC) , (R-PP) / (E) , is in the range from 2 to 5.

In another preferred embodiment, the polypropylene composition (PC) has a melting temperature (ISO 11357) in the range from 110 to 125 ℃, more preferably in the range from 112 to 120 ℃.

In another preferred embodiment, the polypropylene composition (PC) has a Vicat softening temperature, method A (ISO 306) in the range from 85 to 105 ℃.

In another preferred embodiment, the propylene random copolymer (R-PP) consists of propylene monomer units and ethylene comonomer units.

In another preferred embodiment, the propylene random copolymer (R-PP) has a flexural modulus (ISO 527) of at least 800 MPa.

In another preferred embodiment, the elastomeric ethylene random copolymer (E) has a melt flow rate MFR ₂ (190 ℃, 2.16 kg, ISO 1133) in the range from 0.1 to 2.0 g/10 min.

In another preferred embodiment, the elastomeric ethylene random copolymer (E) consists of ethylene monomer units and 1-octene comonomer units.

In another preferred embodiment, the additives (A) are selected from antioxidants, UV-stabilisers, anti-scratch agents, mould release agents, acid scavengers, lubricants, anti-static agents, and mixtures thereof.

In another preferred embodiment, the polypropylene composition (PC) is free from talc, preferably free from any inorganic fillers.

In another aspect, the present invention is directed to an article comprising, preferably consisting of, the polypropylene composition (PC) .

In a preferred embodiment, the article is a film, preferably a cast film.

In another further preferred embodiment the film is a laminating film for polypropylene articles, preferably polypropylene automotive articles, most preferably polypropylene automotive interior articles.

In a further aspect, the present invention is directed to an automotive interior article, comprising an injection-moulded polypropylene that has been laminated with the film of the present invention, which comprises, preferably consists of, the polypropylene composition (PC) .

In yet a further aspect, the present invention is directed to a use of a film of the present invention for laminating polypropylene articles, preferably for laminating polypropylene automotive articles, most preferably for laminating polypropylene automotive interior articles.

The present invention will now be described in more detail.

The propylene random copolymer (R-PP)

The main component of the polypropylene composition (PC) of the present invention is the propylene random copolymer (R-PP) .

In the context of the present invention, the term propylene random copolymer is understood to not include heterophasic propylene copolymers. That is to say, the propylene random copolymer (R-PP) of the present invention is a monophasic propylene random copolymer.

The propylene random copolymer (R-PP) of the present invention comprises propylene monomer units, and one or more comonomer units selected from ethylene and/or alpha olefins with 4 to 12 carbon atoms preferably in an amount in the range from 2 to 5 wt. -%, more preferably from 2.0 to 5.0 wt. -%, still more preferably from 3.0 to 4.5 wt. -%, most preferably in the range from 3.5 to 4.5 wt. -%, as determined by quantitative ¹³C-NMR spectroscopy.

It is preferred that the propylene random copolymer (R-PP) of the present invention comprises propylene monomer units, and ethylene comonomer units in an amount in the range from 2 to 5 wt. -%, preferably from 2.0 to 5.0 wt. -%, more preferably from 3.0 to 4.5 wt. -%, most preferably in the range from 3.5 to 4.5 wt. -%, as determined by quantitative ¹³C-NMR spectroscopy.

It is further preferred that the propylene random copolymer (R-PP) of the present invention consists of propylene monomer units, and ethylene comonomer units in an amount in the range from 2 to 5 wt. -%, preferably from 2.0 to 5.0 wt. -%, more preferably from 3.0 to 4.5 wt. -%, most preferably in the range from 3.5 to 4.5 wt. -%, as determined by quantitative ¹³C-NMR spectroscopy.

The propylene random copolymer (R-PP) of the present invention has a melt flow rate MFR ₂ (230 ℃, 2.16 kg, ISO 1133) in the range from 0.1 to 15.0 g/10 min, preferably from 0.5 to 10.0 g/10 min, more preferably from 0.8 to 5.0 g/10 min, most preferably in the range from 1.0 to 3.0 g/10 min.

The propylene random copolymer (R-PP) of the present invention has a Vicat softening temperature, method A (ISO 306) in the range from 110 to 140 ℃, preferably from 112 to 135 ℃, more preferably from 114 to 130 ℃, most preferably in the range from 115 to 125 ℃.

It is preferred that the propylene random copolymer (R-PP) of the present invention has a flexural modulus (ISO 527) of at least 800 MPa, preferably of at least 825 MPa, more preferably of at least 850 MPa, most preferably of at least 875 MPa.

The flexural modulus is typically no greater than 1400 MPa.

It is therefore preferred that the propylene random copolymer (R-PP) of the present invention has a flexural modulus (ISO 527) in the range from 800 to 1400 MPa, preferably from 825 to 1300 MPa, more preferably from 850 to 1200 MPa, most preferably in the range from 875 to 1100 MPa.

It is preferred that the polypropylene random copolymer (R-PP) has a xylene cold soluble content (XCS) measured according ISO 16152 (25 ℃) in the range of 2 to 15 wt. -%, preferably in the range of 3 to 10 wt. -%.

The propylene random copolymer (R-PP) of the present invention may either be synthesised or selected from commercially available propylene random copolymers.

The elastomeric ethylene random copolymer (E)

As another essential component, the polypropylene composition (PC) comprises an elastomeric ethylene random copolymer (E) .

The elastomeric ethylene random copolymer (E) of the present invention comprises ethylene monomer units and one or more comonomer units in an amount in the range from 30 to 50 wt. -%, wherein the one or more comonomer units are selected from alpha olefins with 4 to 12 carbon atoms, more preferably selected from 1-hexene and 1-octene, most preferably 1-octene.

It is preferred that the elastomeric ethylene random copolymer (E) of the present invention consists of ethylene monomer units and 1-octene comonomer units.

The comonomer units of the elastomeric ethylene random copolymer (E) are preferably present in the range from 30 to 50 wt. -%, more preferably 35 to 45 wt. -%, as determined by ¹³C-NMR spectroscopy.

The elastomeric ethylene random copolymer (E) of the present invention has a melting temperature (ISO 11357) of at least 75 ℃, preferably of at least 90 ℃, more preferably of at least 100 ℃, most preferably of at least 110 ℃.

The elastomeric ethylene random copolymer (E) of the present invention preferably has a density in the range from 860 to 890 kg/m ³, more preferably from 862 to 880 kg/m ³, most preferably in the range from 865 to 875 kg/m ³.

The elastomeric ethylene random copolymer (E) of the present invention preferably has a melt flow rate MFR ₂ (190 ℃, 2.16 kg, ISO 1133) in the range from 0.1 to 2.0 g/10 min, more preferably from 0.2 to 1.5 g/10 min, most preferably in the range from 0.3 to 1.0 g/10 min.

The elastomeric ethylene random copolymer (E) of the present invention may either be selected from commercially available elastomeric ethylene random copolymers or synthesised directly, preferably the elastomeric ethylene random copolymer (E) is a commercially available elastomeric ethylene random copolymer.

In a particularly preferred embodiment, the elastomeric ethylene random copolymer (E) is the commercial product Engage ^TM XLT 8677 available from the Dow Chemical Company (US) .

The additives (A)

The polypropylene composition (PC) of the present invention may contain additives (A) in an amount of from 0 to 5.0 wt. -%. The skilled practitioner would be able to select suitable additives that are well known in the art.

The additives (A) are preferably selected from antioxidants, UV-stabilisers, anti-scratch agents, mould release agents, acid scavengers, lubricants, anti-static agents, and mixtures thereof.

The skilled practitioner would be aware that talc may be used in similar compositions, either as a nucleating agent, or as an inorganic filler. If talc is present in the polypropylene composition (PC) of the invention then it must be only be present in amounts suitable for its use as a nucleating agent, suitably less than 1.0 wt. -%, more preferably less than 0.5 wt. -%, most preferably less than 0.3 wt. -%.

It is preferred that the polypropylene composition (PC) is free of talc, more preferably free from any type of inorganic fillers.

It is understood that the content of additives (A) , given with respect to the total weight of the polypropylene composition (PC) , includes any carrier polymers used to introduce the additives to said polypropylene composition (PC) , i.e. masterbatch carrier polymers. An example of such a carrier polymer would be a polypropylene homopolymer in the form of powder,

The polypropylene composition (PC)

It is desirable that the polypropylene composition of the present invention has suitable properties for use as a laminating film for injection-moulded polypropylene articles. Important properties are those required for extrusion as a film (melt flow rate and softness) and for lamination (melting temperature) .

Therefore, the polypropylene composition (PC) of the present invention has a melt flow rate MFR ₂ (230 ℃, 2.16 kg, ISO 1133) in the range from 1.0 to 5.0 g/10 min, preferably from 1.1 to 4.0 g/10 min, more preferably from 1.2 to 3.0 g/10 min, most preferably in the range from 1.3 to 2.0 g/10 min.

The polypropylene composition (PC) of the present invention preferably has a melting temperature (ISO 11357) in the range from 110 to 125 ℃, more preferably from 111 to 122 ℃, most preferably in the range from 112 to 120 ℃.

The polypropylene composition (PC) of the present invention preferably has a Vicat softening temperature, method A (ISO 306) in the range from 85 to 105 ℃, more preferably from 88 to 102 ℃, most preferably in the range from 90 to 100 ℃.

The polypropylene composition (PC) of the present invention comprises several essential components, including the propylene random copolymer (R-PP) , the elastomeric ethylene random copolymer (E) and optional additives (A) . Accordingly, the polypropylene composition (PC) comprises:

ii) the Vicat softening temperature, method A (ISO 306) is in the range from 110 to 140 ℃,

wherein the melting temperature (ISO 11357) is at least 75 ℃,

c) from 0 to 5 wt. -%additives (A) .

The propylene random copolymer (R-PP) preferably has a content of comonomer units selected from ethylene and/or alpha-olefins with 4 to 12 carbon atoms in the range from 2 to 5 wt. -%as determined by quantitative ¹³C-NMR spectroscopy,

The elastomeric ethylene random copolymer (E) preferably has a content of comonomer units selected from alpha-olefins with 4 to 12 carbon atoms in the range from 30 to 50 wt. -%as determined by quantitative ¹³C-NMR spectroscopy.

The polypropylene composition (PC) of the present invention can comprise further components, in addition to the essential components as defined above. However, it is preferred that the individual contents of the propylene random copolymer (R-PP) , the elastomeric ethylene random copolymer (E) , and the additives (A) add up to at least 90 wt. -%, more preferably to at least 95 wt. -%, based on the total weight of the polypropylene composition (PC) . Most preferably the polypropylene composition (PC) consists of only (R-PP) , (E) and (A) .

As described above, it is preferred that the polypropylene composition (PC) is free of talc, more preferably free from any type of inorganic fillers.

The polypropylene composition (PC) comprises:

a) from 60 to 90 wt. -%of the propylene random copolymer (R-PP)

b) from 5 to 35 wt. -%of the elastomeric ethylene random copolymer (E)

c) from 0 to 5 wt. -%additives (A) .

The content of propylene random copolymer (R-PP) within the polypropylene composition (PC) is from 60 to 90 wt. -%, more preferably from 63 to 85 wt. -%, most preferably from 65 to 80 wt. -%.

The content of elastomeric ethylene random copolymer (E) within the polypropylene composition (PC) is from 5 to 35 wt. -%, more preferably from 10 to 33 wt. -%, most preferably from 15 to 30 wt. -%.

It is therefore preferred that the polypropylene composition (PC) comprises:

a) from 63 to 85 wt. -%of the propylene random copolymer (R-PP)

b) from 10 to 33 wt. -%of the elastomeric ethylene random copolymer (E)

c) from 0 to 5 wt. -%additives (A) .

It is further preferred that the polypropylene composition (PC) comprises:

a) from 65 to 80 wt. -%of the propylene random copolymer (R-PP)

b) from 15 to 30 wt. -%of the elastomeric ethylene random copolymer (E)

c) from 0 to 5 wt. -%additives (A) .

It is preferred that the ratio of the content of the propylene random copolymer (R-PP) to the content of the elastomeric ethylene random copolymer (E) , (R-PP) / (E) , is in the range from 2 to 5, more preferably from 2.0 to 5.0, most preferably in the range from 2.0 to 4.0.

Preparing and further processing the polypropylene composition (PC) includes mixing the individual components of the polypropylene composition (PC) , for instance by use of a conventional compounding or blending apparatus, e.g. a Banbury mixer, a 2-roll rubber mill, Buss-co-kneader or a twin screw extruder, and then pelletization. A typical extruding temperature is in the range of 160 to 210℃, or more preferably in the range of 180 to 200℃. A film, preferably a cast film, multilayer or monolayer, can be prepared from the pellets of the polypropylene composition (PC) .

The preparation process for the propylene random copolymer (R-PP)

The polymerisation system for the preparation of the propylene random copolymer (R-PP) 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. 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 polymerisation 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 polymerisation stages. Also in such cases, it is necessary to introduce so much cocatalyst into the prepolymerisation stage that a sufficient polymerisation reaction is obtained therein.

It is possible to add other components also to the prepolymerisation stage. Thus, hydrogen may be added into the prepolymerisation 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 prepolymerisation 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 polymerisation 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.

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 propylene random copolymer (R-PP) according to this invention is 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

process.

One preferred multistage process may therefore comprise the steps of:

- producing a propylene random copolymer (R-PP) 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 polymerisation conditions,

- optionally 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,

- recovering the polymer product for further processing.

With respect to the above-mentioned preferred slurry or 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 polymerisation, which preferably is carried out in a loop reactor, is optionally 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 polymerisation 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 propylene random copolymer (R-PP) is obtained by a polymerisation 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 crystallised 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 crystallised or emulsion solidified, is used as catalyst carrier.

In the next step the spray crystallised 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 dialkylphthalate 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 crystallised into a morphologically advantageous form, as for example described in WO 87/07620. This crystallised 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 titanisation 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 one preferred embodiment, the procatalyst is obtained by the emulsion technology developed by Borealis. Reference in this regard is made to WO 2009/040201. Thus, preferably the procatalyst is obtained by a process comprising the steps of:

a) preparing a solution of a complex of a Group 2 metal and an electron donor by reacting a compound of said metal with said electron donor or a precursor thereof in an organic liquid reaction medium;

b) adding said solution of said complex to at least one compound of a transition metal of any of groups 4 -6 to produce an emulsion the dispersed phase of which contains more than 50 mol%of the Group 2 metal in said complex;

c) agitating the emulsion, optionally in the presence of an emulsion stabiliser, in order to maintain the droplets of said dispersed phase within an average particle size range of suitably 5 to 200 μm, preferably 10 to 100 μm, even more preferably 20 to 50 μm;

d) solidifying said droplets of the dispersed phase; and

e) recovering the obtained solidified particles of the olefin polymerisation catalyst.

The Group 2 metal used in the preparation of the procatalyst according to the emulsion technology is preferably magnesium and the liquid organic medium for reacting the group 2 metal compound preferably comprises a C ₆-C ₁₀ aromatic hydrocarbon, preferably toluene. An electron donor compound to be reacted with the Group 2 metal compound preferably is a mono-or diester of an aromatic carboxylic acid or diacid, the latter being able to form a chelate-like structured complex. Said aromatic carboxylic acid ester or diester can be formed in situ by reaction of an aromatic carboxylic acid chloride or diacid dichloride with a C ₂-C ₁₆ alkanol and/or diol, and is preferably dioctyl phthalate or bis- (2-ethylhexyl) phthalate. The reaction for the preparation of the Group 2 metal complex is generally carried out at a temperature of 20 to 80 ℃, and in case that the Group 2 metal is magnesium, the preparation of the magnesium complex may advantageously be carried out at a temperature of 50 to 70 ℃. The compound of a group 4 -6 metal is preferably a compound of a Group 4 metal. The Group 4 metal is preferably titanium, and its compound to be reacted with the complex of a Group 2 metal is preferably a halide. In a still further embodiment of the invention, the compound of a group 4 -6 metal can also be selected from Group 5 and Group 6 metals, such as Cu, Fe, Co, Ni and/or Pd compounds. In a preferred embodiment of the production process of the catalyst a turbulence minimising agent (TMA) is added to the reaction mixture before solidifying said particles of the dispersed phase, the TMA being inert and soluble in the reaction mixture under the reaction conditions. The turbulence minimising agent (TMA) or mixtures thereof are preferably polymers having linear aliphatic carbon backbone chains, which might be branched with only short side chains in order to serve for uniform flow conditions when stirring. Said TMA is in particular preferably selected from α-olefin polymers having a high molecular weight Mw (as measured by gel permeation chromatography) of about 1 to 40 x 10 ⁶, or mixtures thereof. Especially preferred are polymers of α-olefin monomers with 6 to 20 carbon atoms, and more preferably polyoctene, polynonene, polydecene, polyundecene or polydodecene or mixtures thereof, having the molecular weight and general backbone structure as defined before, and most preferably TMA is polydecene. Usually, said turbulence minimising agent can be added in any process step before particle formation starts, i.e. at the latest before solidification of the emulsion, and is added to the emulsion in an amount of 1 to 1000 ppm, preferably 5 to 100 ppm and more preferable 5 to 50 ppm, based on the total weight of the reaction mixture. A preferred embodiment of the present invention the procatalyst is obtained by: preparing a solution of a magnesium complex by reacting an alkoxy magnesium compound and an electron donor or precursor thereof in a C ₆-C ₁₀ aromatic liquid reaction medium comprising C ₆-C ₁₀ aromatic hydrocarbon or a mixture of C ₆-C ₁₀ aromatic hydrocarbon and C ₅-C ₉ aliphatic hydrocarbon; reacting said magnesium complex with a compound of at least one fourvalent group 4 metal at a temperature greater than 10 ℃ and less than 60 ℃, to produce an emulsion of a denser, TiCl ₄/toluene-insoluble, oil dispersed phase having group 4 metal/Mg mol ratio 0.1 to 10 in an oil disperse phase having group 4 metal/Mg mol ratio 10 to 100; maintaining the droplets of said dispersed phase within the size range 5 to 200 μm by agitation in the presence of an emulsion stabiliser while heating the emulsion to solidify said droplets and adding turbulence minimising agent into the reaction mixture before solidifying said droplets of the dispersed phase, said turbulence minimising agent being inert and soluble in the reaction mixture under the reaction conditions; and solidifying said particles of the dispersed phase by heating and recovering the obtained catalyst particles. The said disperse and dispersed phases are thus distinguishable from one another by the fact that the denser oil, if contacted with a solution of titanium tetrachloride in toluene, will not dissolve in it. A suitable TiCl ₄/toluene solution for establishing this criterion would be one having a TiCl ₄/toluene mol ratio of 0.1 to 0.3. The disperse and dispersed phase are also distinguishable by the fact that the great preponderance of the Mg provided (as complex) for the reaction with the Group 4 metal compound is present in the dispersed phase, as revealed by comparison of the respective Group 4 metal/Mg mol ratios. In effect, therefore, virtually the entirety of the reaction product of the Mg complex with the Group 4 metal, which is the precursor of the final catalyst, becomes the dispersed phase, and proceeds through the further processing steps to the final dry particulate form. The disperse phase, still containing a useful quantity of Group 4 metal, can be reprocessed for recovery of that metal. The production of a two-phase, rather than single-phase reaction product is encouraged by carrying out the Mg complex/Group 4 metal compound reaction at low temperature, specifically above 10 ℃ but below 60 ℃, preferably between 20 ℃ and 50 ℃. Since the two phases will naturally tend to separate into a lower, denser phase and supernatant lighter phase, it is necessary to maintain the reaction product as an emulsion by agitation, preferably in the presence of an emulsion stabiliser. The resulting particles from the dispersed phase of the emulsion are of a size, shape (spherical) and uniformity, which render the final catalyst extremely effective in olefin polymerisation. This morphology is preserved during the heating to solidify the particles, and of course throughout the final washing and drying steps. It is, by contrast, difficult to the point of impossibility to achieve such morphology through precipitation, because of the fundamental uncontrollability of nucleation and growth, and the large number of variables, which affect these events. The electron donor is preferably an aromatic carboxylic acid ester, particularly favoured esters being dioctyl phthalate and bis- (2-ethylhexyl) phthalate. The donor may conveniently be formed in situ by reaction of an aromatic carboxylic acid chloride precursor with a C ₂-C ₁₆ alkanol and/or diol. The liquid reaction medium preferably comprises toluene. Furthermore, emulsifying agents/emulsion stabilisers can be used additionally in a manner known in the art for facilitating the formation and/or stability of the emulsion. For the said purposes e.g. surfactants, e.g. a class based on acrylic or methacrylic polymers can be used. Preferably, said emulsion stabilisers are acrylic or methacrylic polymers, in particular those with medium sized ester side chains having more than 10, preferably more than 12 carbon atoms and preferably less than 30, and preferably 12 to 20 carbon atoms in the ester side chain. Particular preferred are unbranched C ₁₂-C ₂₀ acrylates such as poly (hexadecyl) -methacrylate and poly (octadecyl) -methacrylate. It has been found that the best results are obtained when the Group 4 metal/Mg mol ratio of the denser oil is 1 to 5, preferably 2 to 4, and that of the disperse phase oil is 55 to 65. Generally the ratio of the mol ratio Group 4 metal/Mg in the disperse phase oil to that in the denser oil is at least 10. Solidification of the dispersed phase droplets by heating is suitably carried out at a temperature of 70 -150 ℃, usually at 90 -110 ℃.

The finally obtained procatalyst is desirably in the form of particles having an average size range of 5 to 200 μm, preferably 10 to 100 μm, more preferably 20 to 50 μm. The reagents can be added to the aromatic reaction medium in any order. However, it is preferred that in a first step the alkoxy magnesium compound is reacted with a carboxylic acid halide precursor of the electron donor to form an intermediate; and in a second step the obtained product is further reacted with the Group 4 metal. The magnesium compound preferably contains from 1 to 20 carbon atoms per alkoxy group, and the carboxylic acid should contain at least 8 carbon atoms. Reaction of the magnesium compound, carboxylic acid halide and alcohol proceeds satisfactorily at temperatures in the range 20 to 80 ℃, preferably 50 to 70 ℃. The product of that reaction, the "Mg complex" , is reacted with the Group 4 metal compound at a lower temperature, to bring about the formation of a two-phase, oil-in-oil, product. The reaction medium used as solvent can be aromatic or a mixture of aromatic and aliphatic hydrocarbons, the latter one containing preferably 5 -9 carbon atoms, more preferably 5 -7 carbon atoms, or mixtures thereof. Preferably, the liquid reaction medium used as solvent in the reaction is aromatic and is more preferably selected from hydrocarbons such as substituted and unsubstituted benzenes, preferably from alkylated benzenes, even more preferably from toluene and the xylenes, and is most preferably toluene. The molar ratio of said aromatic medium to magnesium is preferably less than 10, for instance from 4 to 10, preferably from 5 to 9. The alkoxy magnesium compound group is preferably selected from the group consisting of magnesium dialkoxides, complexes of a magnesium dihalide and an alcohol, and complexes of a magnesium dihalide and a magnesium dialkoxide. It may be a reaction product of an alcohol and a magnesium compound selected from the group consisting of dialkyl magnesium, alkyl magnesium alkoxides, alkyl magnesium halides and magnesium dihalides.

It can further be selected from the group consisting of dialkyloxy magnesiums, diaryloxy magnesiums, alkyloxy magnesium halides, aryloxy magnesium halides, alkyl magnesium alkoxides, aryl magnesium alkoxides and alkyl magnesium aryloxides. The magnesium dialkoxide may be the reaction product of a magnesium dihalide such as magnesium dichloride or a dialkyl magnesium of the formula R'xR"yMg, wherein x + y = 2 and x and y are in the range of 0.3 -1.7 and each one of R' and R" is a similar or different C ₁-C ₂₀ alkyl, preferably a similar or different C ₄-C ₁₀ alkyl. Typical magnesium alkyls are ethylbutyl magnesium, dibutyl magnesium, dipropyl magnesium, propylbutyl magnesium, dipentyl magnesium, butylpentylmagnesium, butyloctyl magnesium and dioctyl magnesium. Preferably, R' is a butyl group and R" is an octyl group, i.e. the dialkyl magnesium compound is butyl octyl magnesium, most preferably the dialkyl magnesium compound is Mg [ (Bu) _1.5 (Oct) _0.5] .

Dialkyl magnesium, alkyl magnesium alkoxide or magnesium dihalide can react with a polyhydric alcohol R (OH) _m, with m being in the range of 2-4, or a monohydric alcohol ROH or mixtures thereof. Typical C ₂ to C ₆ polyhydric alcohols may be straight-chain or branched and include ethylene glycol, propylene glycol, trimethylene glycol, 1, 2-butylene glycol, 1, 3-butylene glycol, 1, 4-butylene glycol, 2, 3-butylene glycol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 8-octanediol, pinacol, diethylene glycol, triethylene glycol, and triols such as glycerol, methylol propane and pentareythritol. The aromatic reaction medium may also contain a monohydric alcohol, which may be straight or branched chain. Typical C ₁-C ₅ monohydric alcohols are methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec. butanol, tert. butanol, n-amyl alcohol, iso-amyl alcohol, sec. amyl alcohol, tert. amyl alcohol, diethyl carbinol, akt. amyl alcohol, sec. isoamyl alcohol, tert. butyl carbinol. Typical C ₆-C ₁₀ monohydric alcohols are hexanol, 2-ethyl-1-butanol, 4-methyl-2-pentanol, 1-heptanol, 2-heptanol, 4-heptanol, 2, 4-dimethyl-3-pentanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 1-nonanol, 5-nonanol, diisobutyl carbinol, 1-decanol and 2, 7-dimethyl-2-octanol.

Typical >C ₁₀ monohydric alcohols are n-1-undecanol, n-1-dodecanol, n-1-tridecanol, n-1-tetradecanol, n-1-pentadecanol, 1-hexadecanol, n-1-heptadecanol and n-1-octadecanol. The monohydric alcohols may be unsaturated, as long as they do not act as catalyst poisons. Preferable monohydric alcohols are those of formula ROH in which R is a C ₂-C ₁₆ alkyl group, most preferably a C ₄-C ₁₂ alkyl group, particularly 2-ethyl-1-hexanol or 1-octanol.

Preferably, essentially all of the aromatic carboxylic acid ester is a reaction product of a carboxylic acid halide, preferably a dicarboxylic acid dihalide, more preferably an unsaturated, dicarboxylic acid dihalide, most preferably phthalic acid dichloride, with the monohydric alcohol.

The compound of a fourvalent Group 4 metal containing a halogen is preferably a titanium tetrahalide. Equivalent to titanium tetrahalide is the combination of an alkoxy titanium halide and a halogenation agent, which are able to form a titanium tetrahalide in situ. The most preferred halide is the chloride.

As is known, the addition of at least one halogenated hydrocarbon during the procatalyst preparation process can lead to further improved catalytic activity. Reactive halogenated hydrocarbons preferably have the formula R'"X'" _n wherein R'" is a C ₁-C ₂₀ hydrocarbyl group, particularly a C ₁-C ₁₀ aliphatic hydrocarbyl group, X'" is a halogen, preferably chlorine, and n is an integer from 1 to 4.

Such chlorinated hydrocarbons include monochloromethane, dichloromethane, trichloromethane (chloroform) , tetrachloromethane, monochloroethane, (1, 1) -dichloroethane, (1, 2) -dichloroethane, (1, 1, 1) -trichloroethane, (1, 1, 2) -trichloroethane, (1, 1, 1, 2) -tetrachloroethane, (1, 1, 2, 2) -tetrachloroethane, pentachloroethane, hexachloroethane, 1-chloropropane, 2-chloropropane, (1, 2) -dichloropropane, (1, 3) -dichloropropane, (1 2, 3) trichloropropane, 1-chlorobutane, 2-chlorobutane, isobutyl chloride, tert. butyl chloride, (1, 4) -dichlorobutane, 1-chloropentane and (1, 5) -dichloropentane. The chlorinated hydrocarbons may also be unsaturated, provided that the unsaturation does not act as catalyst poison in the final catalyst.

In the above formula, R'" is preferably a C ₁-C ₁₀ alkyl group, X'" is preferably chlorine and n is preferably 1 or 2. Preferred compounds include butyl chloride (BuCl) , dichloroalkanes such as (1, 4) -dichlorobutane, and tertiary butyl chloride.

The catalyst preparation as described herein can be carried out batchwise, semi-continuously or continuously. In such a semi-continuous or continuous process, the solution of the complex of the group 2 metal and said electron donor, which is prepared by reacting the compound of said metal with said electron donor in an organic liquid reaction medium, is mixed with at least one compound of a transition metal, which might be solved in the same or different organic liquid reaction medium. The so obtained solution is then agitated, possibly in the presence of an emulsion stabiliser, and then the agitated emulsion is fed into a temperature gradient reactor, in which the emulsion is subjected to a temperature gradient, thus leading to solidifying the droplets of a dispersed phase of the emulsion. The TMA is preferably contained in the solution of the complex or added to the solution before feeding the agitated solution to the temperature gradient reactor.

When feeding said agitated emulsion to the temperature gradient reactor, an inert solvent, in which the droplets are not soluble, can additionally be fed into that gradient reactor in order to improve the droplet formation and thus leading to a uniform grain size of the particles of the catalyst, which are formed in the temperature gradient reactor when passing through said line. Such additional solvent might be the same as the organic liquid reaction medium, which is used for preparing the solution of the complex of the group 2 metal as explained above in more detail.

The solidified particles of the catalyst can subsequently be recovered by an in-stream filtering unit and are preferably subjected to washing in order to remove unreacted starting components.

The recovered particulate product is washed at least once, preferably at least twice, most preferably at least three times with a hydrocarbon, which preferably is selected from aromatic and aliphatic hydrocarbons, preferably with toluene, particularly with hot (e.g. 90 ℃) toluene, which may include a small amount, preferably about 0.01 -10 vol%of TiCl ₄ or an alkyl aluminium chloride, such as diethyl aluminium chloride (DEAC) , in it. A further washing step is advantageously performed with heptane, most preferably with hot (e.g. 90 ℃) heptane, and a still further washing step with pentane. A washing step typically includes several substeps. A favoured washing sequence is, for example, one washing step with toluene at 90 ℃, two washing steps with heptane at 90 ℃ and one or two washing steps with pentane at room temperature.

Finally, the washed catalyst is dried, e.g. by evaporation or flushing with nitrogen.

The catalyst system, which is used according to the present invention, also comprises a cocatalyst, preferably an aluminium alkyl compound, as defined in detail below. In case the procatalyst is produced by emulsion technology the cocatalyst is added, in pure form or in the form of a solution, from shortly before the beginning of the emulsion formation until adding it to the washing liquid, e.g. toluene, in such an amount that the final Al content of the particles is from 0.05 to 1 wt. -%, preferably 0.1 to 0.8 wt. -%and most preferably 0.2 to 0.7 wt. -%by weight of the final catalyst particles. The most preferred Al content may vary depending upon the type of the Al compound and on the adding step. For example, in some cases the most preferred amount may be 0.1 to 0.4 wt. -%.

In a further 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 propylene random copolymer (R-PP) according to this invention. The polymerised vinyl compound can act as an α-nucleating agent.

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 polymerisation reaction.

As mentioned above, for the production of the propylene random copolymer (R-PP) 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 (III)

Si (OCH ₃) ₂R ₂ ⁵ (III)

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.

More specific examples of the hydrocarbyloxy silane compounds which are useful as external electron donors in the invention are diphenyldimethoxy silane, dicyclopentyldimethoxy silane (D-Donor) , dicyclopentyldiethoxy silane, cyclopentylmethyldimethoxy silane, cyclopentylmethyldiethoxy silane, dicyclohexyldimethoxy silane, dicyclohexyldiethoxy silane, cyclohexylmethyldimethoxy silane (C-Donor) , cyclohexylmethyldiethoxy silane, methylphenyldimethoxy silane, diphenyldiethoxy silane, cyclopentyltrimethoxy silane, phenyltrimethoxy silane, cyclopentyltriethoxy silane, phenyltriethoxy silane. Most preferably, the organo silane compounds are diethylamino-triethoxy-silane (U-Donor) , cyclohexylmethyl dimethoxy silane (C-Donor) , or dicyclopentyl dimethoxy silane (D-Donor) , the latter especially preferred.

The properties of the propylene random copolymer comprising ethylene and/or C ₄ to C ₁₂ α-olefin (R-PP) , produced with the above-outlined process may be adjusted and controlled with the process conditions as known to the skilled person, for example by one or more of the following process parameters: temperature, hydrogen feed, comonomer feed, propylene feed, catalyst, type and amount of external donor, split between two or more components of a multimodal polymer.

Preparation of the polypropylene compositions (PC)

For mixing the individual components of the instant polypropylene composition, a conventional compounding or blending apparatus, e.g. a Banbury mixer, a 2-roll rubber mill, Buss-co-kneader or a twin screw extruder may be used. Preferably, mixing is accomplished in a co-rotating twin screw extruder. The polymer materials recovered from the extruder are usually in the form of pellets. These pellets are then preferably further processed, e.g. by compression molding to generate articles and products of the inventive polypropylene composition (PC) .

Films

The present invention also relates to films comprising the polypropylene composition (PC) of the present invention.

Preferably the films of the present invention comprise at least 90 wt. -%, more preferably at least 95 wt. -%, still more preferably at least 97 wt. -%, even more preferably at least 99 wt. -%of the polypropylene composition (PC) of the present invention, with respect to the total weight of the film.

It is especially preferred that the films of the present invention consist of the propylene composition (PC) of the present invention.

Preferably the films of the present invention are cast films.

It is particularly preferred that the films of the present invention are laminating films for polypropylene articles, preferably polypropylene automotive articles, most preferably polypropylene automotive interior articles.

The term interior indicates that the article is not part of the car exterior, but of the car’s interior. Preferred automotive interior articles include door modules, seat structures, armrests, pedals, dashboards and interior trims.

The present invention is also directed, therefore, to an automotive interior article, comprising an injection-moulded polypropylene that has been laminated with a film according to the present invention, which comprises, preferably consists of, the polypropylene composition (PC) .

Laminated automotive interior articles according to the present invention would be free of typical aesthetic defects typically associated with the injection moulding process, such as tiger stripe, gloss differences, etc.

A further aspect of the present invention is the use of the films according to the present invention for laminating polypropylene articles, preferably for laminating polypropylene automotive articles, most preferably for laminating polypropylene automotive interior articles.

Preferably the films of the present invention are used to laminate injection-moulded polypropylene articles, more preferably injection-moulded polypropylene automotive articles, most preferably injection-moulded polypropylene automotive interior articles.

This use of the films of the present invention in the lamination of injection-moulded articles helps to avoid unfavourable aesthetic defects typically associated with the injection moulding process, such as tiger stripe, gloss differences, etc.

The present invention will now be described in further detail by the examples provided below. It would be apparent to the skilled practitioner that the below examples are only illustrative, and do not impose any further limitations on the invention as described above.

EXAMPLES

1. Definitions/Measuring Methods

The following definitions of terms and determination methods apply for the above general description of the invention as well as to the below examples unless otherwise defined.

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

Melting temperature Tm is measured according to ISO 11357-3

MFR ₂ is measured according to ISO 1133 (230 ℃, 2.16 kg load) .

Quantification of comonomer content by FTIR spectroscopy

The comonomer content is determined by quantitative Fourier transform infrared spectroscopy (FTIR) after basic assignment calibrated via quantitative ¹³C nuclear magnetic resonance (NMR) spectroscopy in a manner well known in the art. Thin films are pressed to a thickness of between 100-500 μm and spectra recorded in transmission mode.

Specifically, the ethylene content of a polypropylene-co-ethylene copolymer is determined using the baseline corrected peak area of the quantitative bands found at 720-722 and 730-733 cm ^-1. Quantitative results are obtained based upon reference to the film thickness.

The xylene solubles (XCS, wt. -%) : Content of xylene cold solubles (XCS) is determined at 25 ℃according ISO 16152; first edition; 2005-07-01.

Vicat Softening Temperature: The Vicat softening temperature was determined according to Method A of ISO 306.

2. Examples

2.1. Synthesis of propylene random copolymer (R-PP)

The catalyst used for the preparation of R-PP is a self-supported Ziegler-Natta catalyst described in WO 2004/029112; as co-catalyst triethyl-aluminium (TEAL) and as donor dicyclo pentyl dimethoxy silane were used. R-PP was polymerized in a sequential reactor process, as described in Table 1:

Table 1: Preparation of propylene random copolymer (R-PP) by sequential polymerization:

		R-PP
Prepolymerisation
Residence time	[mins]	19
Temperature	[℃]	30
Pressure	[bar]	55
Donor/C ₃	[g/ton]	65
Co-catalyst/C ₃	[g/ton]	130
Loop
Residence time	[h]	1.5
Temperature	[℃]	70
Pressure	[bar]	55
H ₂/C ₃ ratio	[mol/kmol]	0.05
C ₂/C ₃ ratio	[mol/kmol]	34
MFR ₂	[g/10min]	3.0
XCS	[wt%]	6.7
C2 content	[wt%]	3.5
split (Prepol + Loop)	[wt%]	45
GPR
Residence time	[h]	1.9
Temperature	[℃]	85
Pressure	[kPa]	21
H ₂/C ₃ ratio	[mol/kmol]	7.5
C ₂/C ₃ ratio	[mol/kmol]	33
MFR ₂ (230℃/2.16kg)	[g/10min]	1.5
XCS	[wt%]	6.0
C2 content	[wt%]	4.2
Split (loop/gpr)	[wt%]	55

2.2. Compounding of examples

The propylene compositions of Inventive examples IE1 to IE3 and comparative example CE1 were prepared based on the recipes indicated in Table 2 by compounding in a co-rotating twin-screw extruder under the conditions described in Table 3.

Table 2: Recipes for Inventive and Comparative Examples and properties thereof.

HomoPP Propylene homopolymer, commercially available from Borouge Pte Co. (Singapore) with trade name “HG385MO”

Engage ^TM XLT 8677 Ethylene/1-octene elastomer with a density of 870 kg/m ³, a melt flow rate MFR ₂ (190 ℃, 2.16 kg) of 0.50 g/10 min and a melting temperature of 118 ℃. Engage ^TM XLT 8677 is commercially available from the Dow Chemical Company (US)

PP-H, GD 225 Propylene homopolymer carrier in powder form having melting temperature of 160 ℃;

Irgafos 168 Tris (2, 4-di-t-butylphenyl) phosphite (CAS-no. 31570-04-4) , of BASF SE having melting temperature of 182 ℃

Irganox 1076 Octadecyl-3- (3, 5-di-tert. butyl-4-hydroxyphenyl) propionate (CAS-no. 2082-79-3) of BASF SE having melting temperature of 50 ℃;

CaSt Calcium Stearate, CAS-No 1592-23-0, is commercially available from Faci

Rikemal AS-105 Glycerol monostearate, CAS No. 31566-31-1, is commercially available from Riken Vitamin

Table 3: Conditions for compounding inventive propylene compositions

As can be seen from the examples, the inventive polypropylene composition according to the invention has much superior properties for the formation of a laminating film, with the Vicat A temperature and melt flow rate much lower, and within the range required for the extrusion of films and the melting temperature far higher than room temperature and suitable for laminating interior of automotive. The use of such films for the lamination of injection-moulded automotive interior articles can be expected to reduce the appearance of aesthetic defects typically associated with injection-moulded articles.

Claims

A polypropylene composition (PC) comprising

a) from 60 to 90 wt. -%of a propylene random copolymer (R-PP) with propylene monomer units and one or more comonomer units selected from ethylene and/or alpha-olefins with 4 to 12 carbon atoms, wherein

i) the melt flow rate MFR ₂ (230 ℃, 2.16 kg, ISO 1133) is in the range from 0.1 to 15.0 g/10 min, and

ii) the Vicat softening temperature, method A (ISO 306) is in the range from 110 to 140 ℃,

b) from 5 to 35 wt. -%of an elastomeric ethylene random copolymer (E) with ethylene monomer units and one or more comonomer units selected from alpha-olefins with 4 to 12 carbon atoms,

wherein the melting temperature (ISO 11357) is at least 75 ℃,

c) from 0 to 5 wt. -%additives (A) ,

wherein the wt. -%given for each component is with respect to the total weight of the polypropylene composition, and the polypropylene composition has a melt flow rate MFR ₂ (230 ℃, 2.16 kg, ISO 1133) in the range from 1.0 to 5.0 g/10 min.
The polypropylene composition (PC) according to claim 1, wherein the propylene random copolymer (R-PP) has a content of comonomer units selected from ethylene and/or alpha-olefins with 4 to 12 carbon atoms in the range from 2 to 5 wt. -%as determined by quantitative 13C-NMR spectroscopy.
The polypropylene composition (PC) according to claim 1 or 2, wherein the elastomeric ethylene random copolymer (E) has a content of comonomer units selected from alpha-olefins with 4 to 12 carbon atoms in the range from 30 to 50 wt. -%as determined by quantitative ¹³C-NMR spectroscopy.
The polypropylene composition (PC) according to any one of the preceding claims, wherein the combined content of (R-PP) , (E) and (A) is at least 90 wt. -%, preferably at least 95 wt. -%, most preferably the propylene composition (PC) consists of (R-PP) , (E) and (A) .
The polypropylene composition (PC) according to any one of the preceding claims, wherein the ratio of the content of the propylene random copolymer (R-PP) to the content of the elastomeric ethylene random copolymer (E) , (R-PP) / (E) , is in the range from 2 to 5.
The polypropylene composition (PC) according to any one of the preceding claims, having a melting temperature (ISO 11357) in the range from 110 to 125 ℃, more preferably in the range from 112 to 120 ℃.
The polypropylene composition (PC) according to any one of the preceding claims, having a Vicat softening temperature, method A (ISO 306) in the range from 85 to 105 ℃.
The polypropylene composition (PC) according to any one of the preceding claims, wherein the propylene random copolymer (R-PP) consists of propylene monomer units and ethylene comonomer units.
The polypropylene composition (PC) according to any one of the preceding claims, wherein the propylene random copolymer (R-PP) has a flexural modulus (ISO 527) of at least 800 MPa.
The polypropylene composition (PC) according to any one of the preceding claims, wherein the elastomeric ethylene random copolymer (E) has a melt flow rate MFR ₂ (190 ℃, 2.16 kg, ISO 1133) in the range from 0.1 to 2.0 g/10 min.
The polypropylene composition (PC) according to any one of the preceding claims, wherein the elastomeric ethylene random copolymer (E) consists of ethylene monomer units and 1-octene comonomer units.
The polypropylene composition (PC) according to any one of the preceding claims, wherein the additives (A) are selected from antioxidants, UV-stabilisers, anti-scratch agents, mould release agents, lubricants, anti-static agents, acid scavengers, and mixtures thereof.
The polypropylene composition (PC) according to any one of the preceding claims, which is free from talc, preferably free from any inorganic fillers.
A film comprising, preferably consisting of, the polypropylene composition (PC) according to any one of the preceding claims, preferably a cast film.
The film according to claim 14, wherein the film is a laminating film for polypropylene articles, preferably polypropylene automotive articles, most preferably polypropylene automotive interior articles.
An automotive interior article, comprising an injection-moulded polypropylene article that has been laminated with a film according to claims 14 to 15, which comprises, preferably consists of, the polypropylene composition (PC) according to claims 1 to 13.
A use of the film according to claims 14 to 15 for laminating polypropylene articles, preferably for laminating polypropylene automotive articles, most preferably for laminating polypropylene automotive interior articles.