CN113166486B - Polypropylene composition for vehicle light-weight exterior parts - Google Patents

Abstract

The present invention relates to a polypropylene composition comprising a polypropylene random copolymer, a fiber reinforced composition comprising said polypropylene composition, a process for forming said fiber reinforced composition, a vehicle article formed from said fiber reinforced composition and the use of said fiber reinforced composition for the manufacture of a vehicle exterior article.

Description

Polypropylene composition for vehicle light-weight exterior parts

Technical Field

The present invention relates to a polypropylene composition comprising a polypropylene random copolymer, a fiber reinforced composition comprising said polypropylene composition, a process for forming said fiber reinforced composition, a vehicle article formed from said fiber reinforced composition and the use of said fiber reinforced composition for the preparation of a vehicle exterior article.

Background

Polypropylene is a material used in a variety of technical fields, of which glass fiber reinforced polypropylene is commercially important. Among glass fiber reinforced polypropylenes, long fiber reinforced thermoplastics represent readily moldable thermoplastics that have been used to produce a variety of vehicle components.

However, there is a continuing need in the industry for improved vehicle components that are lighter in weight, thinner in thickness, and do not significantly compromise mechanical properties. It has also been found that it is very difficult to reduce the weight and further the thickness of the article by optimizing the direct molding process of long fiber thermoplastics. Therefore, alternatives are needed to achieve such goals.

Disclosure of Invention

It is therefore an object of the present invention to provide a polypropylene composition which, after fiber reinforcement, can be used to produce automotive parts having reduced weight and reduced thickness, and still having acceptable mechanical properties.

The finding of the present invention is that the polypropylene random copolymer can at least partially replace propylene homopolymer in compositions for the production of vehicle parts with good stiffness and excellent impact strength by direct moulding of long fiber thermoplastics, and even reduce the total weight and thickness of such vehicle parts.

Another discovery of the present invention is that the partial replacement of propylene homopolymer in fiber reinforced compositions used to make vehicle articles with polypropylene random copolymer can facilitate direct molding pressure processes to reduce the thickness and weight of the articles due to low crystalline content and lower stiffness.

The present invention therefore relates to a polypropylene composition (PP) comprising:

(a) Polypropylene random copolymer (PP-RACO) comprising at least one monomer selected from ethylene and C ₄ To C ₈ Of an alpha-olefin of (a) or (b),

(b) At least one propylene homopolymer (H-PP), and

(c) A tackifier (AP) which is a polar modified polypropylene,

wherein,

(i) The melt flow Rate MFR of the Polypropylene composition (PP) measured according to ISO1133 ₂ (230 ℃) in the range from 30 to 200g/10min, preferably from 60 to 130g/10min,

(ii) Polypropylene random copolymer (PP-RACO) melt flow Rate MFR measured according to ISO1133 ₂ (230 ℃) in the range from 20 to 180g/10min, preferably from 50 to 120g/10min.

In a preferred embodiment of the polypropylene composition (PP), the polypropylene random copolymer (PP-RACO) comprises 1.0 to 5.0wt% of ethylene and/or C ₄ To C ₈ Of alpha-olefins.

In another preferred embodiment of the polypropylene composition (PP), the polypropylene random copolymer (PP-RACO) has a xylene cold soluble content (XCS) measured according to ISO 6427 (23 ℃) of from 2 to 20 wt. -%, preferably from 3 to 10 wt. -%.

In another preferred embodiment of the polypropylene composition (PP), the polypropylene random copolymer (PP-RACO) has a melting temperature determined according to Differential Scanning Calorimetry (DSC) in the range of 145 to 160 ℃, more preferably 148 to 158 ℃.

In another preferred embodiment of the polypropylene composition (PP), the at least one propylene homopolymer (H-PP) has a melt flow rate MFR measured according to ISO1133 ₂ (23 ℃) of 5 to 220g/10min, more preferably 40 to 150g/10min.

In another preferred embodiment of the polypropylene composition (PP), the at least one propylene homopolymer (H-PP) has a tensile strength at yield, measured according to ISO-527, of at least 30MPa, more preferably at least 35MPa.

In another preferred embodiment of the polypropylene composition (PP), the tackifier (AP) comprises a maleic anhydride grafted polypropylene.

In another preferred embodiment of the polypropylene composition (PP), the polypropylene composition (PP) is monophasic.

In another preferred embodiment of the polypropylene composition (PP), the sum of (a) the polypropylene random copolymer (PP-RACO), (b) the at least one propylene homopolymer (H-PP) and (c) the tackifier (AP) being a polar modified polypropylene is at least 90 wt. -%, more preferably at least 95 wt. -%, based on the total weight of the polypropylene composition (PP).

In another preferred embodiment of the polypropylene composition (PP), the polypropylene composition (PP) comprises:

(a) 60 to 85wt% of a polypropylene random copolymer (PP-RACO),

(b) 13.5 to 35wt% of at least one propylene homopolymer (H-PP),

(c) 1.3 to 5.0 wt.% of a polar modified polypropylene as tackifier (AP), and

(d) 0.2 to 5.0wt% of an additive.

In another aspect, the invention relates to a Fiber Reinforced Composition (FRC) comprising a polymer matrix and fibers (F) embedded in the polymer matrix, wherein

(a) The polymer matrix comprises a polypropylene composition (PP) as described above, and

(b) The fibers (F) are selected from the group consisting of glass fibers, metal fibers, mineral fibers, ceramic fibers, carbon fibers, polymer fibers, graphite fibers and mixtures thereof, and

(c) The polymer matrix is single phase.

In a preferred embodiment of the Fiber Reinforced Composition (FRC), the fibers (F) are glass fibers.

In another preferred embodiment of the Fiber Reinforced Composition (FRC), the composition comprises, based on the total weight of the fiber reinforced composition:

(a) 50 to 90wt% of a polypropylene composition (PP),

(b) 10 to 50wt% of fibres (F).

In another aspect, the present invention relates to a direct method of making a vehicle exterior part by compression molding a long fiber reinforced thermoplastic, the method comprising the steps of:

(a) Providing the Polypropylene composition (PP) of the present invention

(b) Adding fibers (F) to the polypropylene composition (PP) and mixing, and

(c) Extruding a mixture comprising said polypropylene (PP) and said fibers from an extruder to obtain a sheet of a fiber-reinforced composition (FRC), and

(d) The sheet is molded in a molding press to form the outer component.

In another aspect, the present invention relates to an automotive article comprising the Fiber Reinforced Composition (FRC) of the present invention.

In a preferred embodiment of the vehicle article, the vehicle article is a molded article, or even more preferably a compression molded article.

In another preferred embodiment of the vehicle article, the vehicle article is selected from the group consisting of vehicle exterior parts, preferably body shields, side trims, pedal assist devices, body panels, and spoilers, most preferably body shields.

In another aspect, the present invention relates to the use of a fiber reinforced composition of the present invention comprising the polypropylene random copolymer (PP-RACO) of the present invention for the preparation of an automotive exterior article.

Detailed Description

The present invention will be described in detail below.

The desired mechanical properties of the fiber-reinforced composite and any molded article obtained from such a fiber-reinforced composition (FRC) are to a large extent influenced by the properties of the selected polypropylene composition (PP) comprising the polypropylene random copolymer (PP-RACO), at least one propylene homopolymer (H-PP) and the tackifier (AP) added mainly to improve the adhesion and insertion of the fibers.

Polypropylene composition (PP)

Since the polypropylene composition (PP) and the Fiber Reinforced Composition (FRC) comprising the polypropylene composition (PP) are intended to be processed (preferably by compression molding) into molded vehicle articles, the polypropylene composition (PP) as well as the Fiber Reinforced Composition (FRC) need to have a specific processability, i.e. a specific plasticity. It is therefore very important for polypropylene compositions (PP) as well as Fibre Reinforced Compositions (FRC) that these compositions need to have a specific melt flow rate.

Thus, the MFR of the polypropylene composition (PP) ₂ (230 ℃) is at least 30g/10min. The upper limit may be 200g/10min. Preferably the melt flow rate MFR of the polypropylene composition (PP) ₂ (230 ℃) of 45 to 150g/10min, more preferably 60 to 130g/10min, still more preferably 70 to 110g/10min, most preferably 80 to 100g/10min.

Preferably, the polypropylene composition (PP) has a tensile stress determined according to ISO527 of at least 25MPa, more preferably from 27 to 35MPa, or even more preferably from 28 to 33MPa.

Preferably, the polypropylene composition (PP) has an elastic modulus determined according to ISO-178 of at least 950MPa, more preferably from 1000 to 1450MPa, or even more preferably from 1150 to 1300MPa.

Preferably, the polypropylene composition (PP) is characterized in that it has a Charpy notched impact strength at 23 ℃ of 2.5 to 6.0kJ/m, determined according to ISO 179 1eA ² More preferably 3.0 to 5.0kJ/m ² Most preferably 3.2 to 4.0kJ/m ² 。

The polypropylene composition (PP) of the present invention comprises a number of essential ingredients including: polypropylene random copolymer (PP-RACO), at least one propylene homopolymer (H-PP) and a tackifier (AP). Thus, the polypropylene composition (PP) comprises:

(a) Polypropylene random copolymer (PP-RACO) comprising at least one monomer selected from ethylene and C ₄ To C ₈ Of an alpha-olefin of (a) or (b),

(b) At least one propylene homopolymer (H-PP), and

(c) A tackifier (AP) which is a polar modified polypropylene, wherein,

(i) The melt flow Rate MFR of the Polypropylene composition (PP) measured according to ISO1133 ₂ (230 ℃) of 30 to 200g/10min, preferably60 to 130g/10min, and

(ii) Polypropylene random copolymer (PP-RACO) melt flow Rate MFR measured according to ISO1133 ₂ (230 ℃) in the range from 20 to 180g/10min, preferably from 50 to 120g/10min.

The polypropylene composition (PP) of the present invention may comprise other components in addition to the above-mentioned essential components. Preferably, however, the sum of (a) the polypropylene random copolymer (PP-RACO), (b) the at least one propylene homopolymer (H-PP) and (c) the tackifier (AP) being a polar modified polypropylene is at least 90wt%, more preferably at least 95wt%, based on the total weight of the polypropylene composition (PP).

The polypropylene composition (PP) of the present invention has the following preferred amounts of the components of the composition:

one preferred composition of the polypropylene composition (PP) comprises:

(a) 60 to 85wt% of a polypropylene random copolymer (PP-RACO),

(b) 13.5 to 35wt% of at least one propylene homopolymer (H-PP),

(c) 1.3 to 5.0 wt.% of a polar modified polypropylene as tackifier (AP), and

(d) 0.2 to 5.0wt% of an additive.

Another preferred composition of the polypropylene composition (PP) consists of:

(a) 60 to 85wt% of a polypropylene random copolymer (PP-RACO),

(b) 13.5 to 35wt% of at least one propylene homopolymer (H-PP),

(c) 1.3 to 5.0 wt.% of a polar modified polypropylene as tackifier (AP), and

(d) 0.2 to 5.0wt% of an additive.

Another preferred composition of the polypropylene composition (PP) comprises:

(a) 60 to 85wt% of a polypropylene random copolymer (PP-RACO),

(b) 13.5 to 35wt% of at least one propylene homopolymer (H-PP),

(c) 1.3 to 5.0 wt.% of a polar modified polypropylene as tackifier (AP), and

(d) 0.1 to 1.5 wt.% of an antioxidant, and

(e) 0.1 to 1.0wt% of a colorant.

Another preferred composition of the polypropylene composition (PP) consists of:

(a) 60 to 85wt% of a polypropylene random copolymer (PP-RACO),

(b) 13.5 to 35wt% of at least one propylene homopolymer (H-PP),

(c) 1.3 to 5.0 wt.% of a polar modified polypropylene as tackifier (AP), and

(d) 0.1 to 1.5 wt.% of an antioxidant, and

(e) 0.1 to 1.0wt% of a colorant.

Another preferred composition of the polypropylene composition (PP) comprises:

(a) 60 to 85wt% of a polypropylene random copolymer (PP-RACO),

(b) 13.5 to 35wt% of at least one propylene homopolymer (H-PP),

(c) 1.3 to 5.0 wt.% of a polar modified polypropylene as tackifier (AP), and

(d) 0.1 to 1.5 wt.% of an antioxidant, and

(e) 0.1 to 1.0wt% of carbon black.

Another preferred composition of the polypropylene composition (PP) consists of:

(a) 60 to 85wt% of a polypropylene random copolymer (PP-RACO),

(b) 13.5 to 35wt% of at least one propylene homopolymer (H-PP),

(c) 1.3 to 5.0 wt.% of a polar modified polypropylene as tackifier (AP), and

(d) 0.1 to 1.5 wt.% of an antioxidant, and

(e) 0.1 to 1.0wt% of carbon black.

The preparation and further processing of the polypropylene composition (PP) comprises: the individual components of the polypropylene composition (PP) according to the invention are mixed, for example by means of conventional mixing or blending equipment, such as a Banbury mixer, a two-roll rubber mill, a Buss co-kneader or a twin-screw extruder. Typical extrusion temperatures are from 160 to 210 ℃, or more preferably from 180 to 200 ℃. The polymeric material recovered from the extruder is typically in the form of pellets. These pellets are then preferably further processed to obtain a Fiber Reinforced Composition (FRC) and are in turn compression molded to produce a vehicle article, i.e. a vehicle (exterior) article.

Polypropylene random copolymer (PP-RACO)

The polypropylene composition (PP) of the invention has the main component of polypropylene random copolymer (PP-RACO).

The polypropylene random copolymer (PP-RACO) of the present invention has a melt flow Rate MFR determined according to ISO1133 ₂ (230 ℃) in the range of 20 to 180g/10min, preferably 35 to 140g/10min, more preferably 50 to 120g/10min, most preferably 60 to 90g/10min.

In a preferred embodiment, the polypropylene random copolymer (PP-RACO) is single phase. The term "monophasic" means that the polypropylene random copolymer (PP-RACO) forms one continuous phase but not more than one continuous phase.

As regards the comonomers, the polypropylene random copolymer (PP-RACO) comprises (preferably consists of): ethylene and/or at least one C ₄ -C ₈ Preferably at least one alpha-olefin selected from the group consisting of ethylene, 1-butene, 1-pentene, 1-hexene and 1-octene, more preferably ethylene and/or 1-butene, but most preferably ethylene.

Preferably the polypropylene random copolymer (PP-RACO) of the present invention comprises ethylene and/or C in an amount of less than 6wt% ₄ To C ₈ An alpha-olefin. More preferably, ethylene and/or C ₄ To C ₈ Is 1.0 to 5.0wt%, or even more preferably 2.0 to 4.0wt%, such as in particular 3.0 to 3.8wt%.

It is also preferred that the polypropylene random copolymer (PP-RACO) has a xylene cold soluble content (XCS) determined according to ISO 6427 (23 ℃) in the range of from 2 to 20 wt. -%, preferably in the range of from 3 to 10 wt. -%, more preferably in the range of from 4 to 8 wt. -%, most preferably in the range of from 4.5 to 6.0 wt. -%.

It is also preferred that the polypropylene random copolymer (PP-RACO) has a melting temperature as determined by Differential Scanning Calorimetry (DSC) in the range of 145 to 160 ℃, more preferably 148 to 158 ℃, even more preferably 150 to 156 ℃, most preferably 152 to 155 ℃.

It is also preferred that the polypropylene random copolymer (PP-RACO) has a crystallization temperature as determined by Differential Scanning Calorimetry (DSC) of 105 to 135 ℃, more preferably 115 to 140 ℃, even more preferably 120 to 135 ℃, most preferably 123 to 130 ℃.

Preferably, the polypropylene random copolymer (PP-RACO) has a tensile yield stress, determined according to ISO527, of at least 25MPa, more preferably from 26 to 35MPa, or even more preferably from 27 to 30MPa.

Preferably, the polypropylene random copolymer (PP-RACO) has a flexural modulus determined according to ISO 178 of at least 850MPa, more preferably of from 950 to 1500MPa, or even more preferably of from 1050 to 1300MPa.

Preferably, the polypropylene composition (PP) is characterized in that it has a Charpy notched impact strength at 23 ℃ measured according to ISO 179 1eA of 2.5 to 6.0kJ/m ² More preferably 3.5 to 5.0kJ/m ² Most preferably 4.0 to 4.8kJ/m ² 。

Propylene homopolymer (H-PP)

As a further essential constituent, the polypropylene composition (PP) comprises at least one propylene homopolymer (H-PP). Preferably, the at least one propylene homopolymer (H-PP) is present in the polypropylene composition (PP) only as a single propylene homopolymer (H-PP). In contrast thereto, it is also possible that more than one propylene homopolymer (H-PP) is present in the polypropylene composition (PP), for example a combination of a first propylene homopolymer (H-PP-1) and a second propylene homopolymer (H-PP-2), or even a further third propylene homopolymer (H-PP-3).

Most importantly, at least one propylene homopolymer (H-PP) is included in the present invention to maintain sufficient rigidity of the polypropylene composition (PP) of the present invention and molded articles made therefrom. Further, when the at least one propylene homopolymer (H-PP) and the polypropylene random copolymer (PP-RACO) are mixed to obtain the polypropylene composition (PP), the at least one propylene homopolymer (H-PP) is also used to adjust the processability of the polypropylene composition (PP) by adjusting the melt flow rate of the polypropylene composition (PP) to allow proper plasticity.

Preferably at least one propylene homopolymer (H-PP) having a melt flow rate MFR determined according to ISO1133 ₂ (230 ℃) of 5 to 220g/10min, more preferably of 40 to 150g/10min, even more preferably of 50 to 80g/10min. If only one propylene homopolymer (H-PP) is included in the compositionIn the polypropylene composition (PP) of the present invention, the melt flow rate of the propylene homopolymer (H-PP) component must be as defined above.

However, if more than one propylene homopolymer (H-PP) is present in the polypropylene composition (PP), i.e. if a blend of two, three or more than three propylene homopolymers (H-PP-1, H-PP-2, H-PP-3, etc.) is present in the polypropylene composition (PP) of the invention, only one propylene homopolymer (H-PP-1) has a melt flow rate MFR determined according to ISO1133 ₂ (230 ℃) must be from 5 to 220g/10min, more preferably from 40 to 150g/10min, even more preferably from 50 to 80g/10min, whereas the other propylene homopolymers (H-PP-2, H-PP-3, etc.) present in the polypropylene composition (PP) of the invention have a melt flow rate MFR determined according to ISO1133 ₂ The range of (230 ℃) may be different from the range defined for the first propylene homopolymer (H-PP-1).

For example, if more than one propylene homopolymer (H-PP) is present in the polypropylene composition (PP), any additional propylene homopolymer (H-PP-2, H-PP-3, etc.) will have a melt flow rate MFR determined according to ISO1133 ₂ (230 ℃) may be in the very high range of 1000 to 2000g/10min, more preferably 1500 to 1900g/10min, or even more preferably 1700 to 1850g/10min. Such additional propylene homopolymers (H-PP-2, H-PP-3, etc.) are very suitable for adjusting the melt flow rate of the polypropylene composition (PP) upwards based on the addition of only a relatively limited amount of additional components. One such preferred propylene homopolymer (H-PP-2) having very high melt flow rates is obtainable by LyondellBasell under the trade name methocene MF 650Y.

Preferably, the at least one propylene homopolymer (H-PP) has a tensile yield strength determined according to ISO527 of at least 30MPa, more preferably at least 35MPa. If more than one propylene homopolymer (H-PP) is present, only one propylene homopolymer (H-PP-1) needs to have a tensile yield strength of at least 30MPa, more preferably at least 35MPa, determined according to ISO 527.

Preferably, the flexural modulus of the at least one propylene homopolymer (H-PP) measured according to ISO 178 is preferably at least 1500MPa, more preferably from 1600 to 2000MPa, or even more preferably from 1600 to 1750MPa. If more than one propylene homopolymer (H-PP) is present, only one propylene homopolymer (H-PP-1) needs to have a flexural modulus as defined above.

At least one propylene homopolymer (H-PP) having a Charpy notched impact strength at 23 ℃ measured according to ISO 179 1eA in the range from 1.5 to 5.0kJ/m ² More preferably 2.0 to 4.0kJ/m ² Most preferably 2.5 to 3.0kJ/m ² . If more than one propylene homopolymer (H-PP) is present, only one propylene homopolymer (H-PP-1) needs to have the Charpy notched impact strength at 23 ℃ as defined above.

Tackifier (AP)

The polypropylene composition (PP) further comprises a tackifier (AP).

The Adhesion Promoter (AP) preferably comprises a modified (functionalized) polymer and optionally a low molecular weight compound having reactive polar groups. Modified alpha-olefin polymers, particularly propylene homopolymers and copolymers, such as copolymers of ethylene and propylene with each other or with other alpha-olefins, are most preferred because of their high compatibility with the polymers of the fiber reinforced composition. Modified polyethylenes may also be used.

For the structure, the modifying polymer is preferably selected from graft or block copolymers.

In this context, preference is given to modified polymers which comprise groups which are derived from polar compounds, in particular from the group consisting of anhydrides, carboxylic acids, carboxylic acid derivatives, primary amines, secondary amines, hydroxyl compounds, oxazolines and epoxides, and also ionic compounds.

Specific examples of the polar compound are unsaturated cyclic anhydrides and aliphatic diesters and diacid derivatives thereof. In particular, maleic anhydride and a compound selected from the group consisting of: c ₁ To C ₁₀ Linear and branched dialkyl maleates, C ₁ To C ₁₀ Linear and branched dialkyl fumarates, itaconic anhydride, C ₁ To C ₁₀ Linear and branched dialkyl itaconates, maleic acid, fumaric acid, itaconic acid, and mixtures thereof.

Particular preference is given to using maleic anhydride-grafted propylene polymers as modifying polymers, i.e.as tackifiers (AP)

The modified polymer, i.e. the tackifier (AP), can be produced in a simple manner by reactive extrusion of the polymer, for example with maleic anhydride in the presence of a free-radical generator, such as an organic peroxide, which is disclosed, for example, in EP 0572028.

The preferred amount of groups derived from the polar compound in the modified polymer (i.e., tackifier (AP)) is 0.5 to 5.0 wt.%, more preferably 0.5 to 4.0 wt.%, still more preferably 0.5 to 3.0 wt.%.

Melt flow Rate MFR of the modified Polymer (i.e., tackifier (AP))) ₂ A preferred value of (230 ℃) is 1.0 to 500g/10min, more preferably 10 to 200g/10min.

Additive agent

The compositions of the invention may additionally comprise typical other additives such as carbon black, other pigments, antioxidants, UV stabilizers, nucleating agents, antistatic agents and slip agents, in conventional amounts, useful for example in the automotive field.

A preferred additive is an antioxidant. Another important additive for obtaining molded vehicle articles, which is highly relevant to the polypropylene composition of the present invention, is a colorant, including pigments, in particular carbon black.

Optionally, a masterbatch may also be comprised in the polypropylene composition (PP) of the present invention. The term masterbatch refers to polymer-bound additives, such as colors and additive concentrates, physically or chemically bound to or within the polymer. It will be appreciated that such a masterbatch contains as little polymer as possible.

Preparation method of polypropylene random copolymer (PP-RACO)

The polymerization system used to prepare the polypropylene random copolymer (PP-RACO) may comprise more than one conventional stirred slurry phase reactor and/or more than one gas phase reactor. Preferably, the reactor used is selected from the group consisting of loop reactors and gas phase reactors, in particular, the process employs at least one loop reactor. It is also possible to use a plurality of reactors of various types, for example one loop reactor and two or three gas phase reactors in series, or two loop reactors and one or two gas phase reactors in series.

Preferably, the process further comprises a prepolymerization with a selected catalyst system comprising a ziegler natta procatalyst (procatalyst), an external donor and a cocatalyst as described in detail below.

In a preferred embodiment, the prepolymerization is carried out in bulk slurry phase polymerization in liquid propylene, i.e. the liquid phase comprises mainly propylene, and minor amounts of other reactants and optionally inert ingredients dissolved therein.

The prepolymerization is generally carried out at a temperature of from 0 to 50 ℃, preferably from 10 to 45 ℃, more preferably from 15 to 40 ℃.

The pressure in the prepolymerization reactor is not critical but must be high enough to keep the reaction mixture in the liquid phase. Thus, the pressure may be 20 to 100bar, for example 30 to 70bar.

The catalyst components are preferably all introduced in the prepolymerization stage. However, in the case where the solid catalyst component (i) and the cocatalyst (ii) may be fed separately, only a part of the cocatalyst may be introduced in the prepolymerization stage, and the remaining part may be introduced in the subsequent polymerization stage. And in this case it is necessary to introduce a sufficient quantity of cocatalyst during the prepolymerization stage to obtain a sufficient polymerization reaction therein.

Other ingredients may also be added during the prepolymerization stage. Thus, hydrogen may be added during the prepolymerization stage to control the molecular weight of the prepolymer, as is known in the art. In addition, antistatic additives may also be used to prevent particles from adhering to each other or to the reactor walls.

Precise control of the prepolymerization conditions and reaction parameters is within the skill of the art.

By slurry phase reactor is meant any reactor, such as a continuous stirred tank reactor or a simple batch stirred tank reactor or a loop reactor, which operates in bulk or slurry phase, in which the polymer is formed in particulate form. "bulk" means polymerization in a reaction medium comprising at least 60 weight percent monomer. According to a preferred embodiment, the slurry phase reactor comprises a bulk loop reactor.

By "gas phase reactor" is meant any mechanically mixed or fluidized bed reactor. Preferably, the gas phase reactor comprises a mechanically stirred fluidized bed reactor, wherein the gas velocity is at least 0.2 m/sec.

A preferred multistage process is a slurry-gas phase process, for example the so-called slurry-gas phase process developed and known from northern Europe chemical

Provided is a 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; which is hereby incorporated by reference.

Another suitable slurry-gas phase process is Basell

And (4) processing.

Preferably, the polypropylene random copolymer (PP-RACO) according to the invention is produced by using a specific Ziegler Natta main catalyst and a specific external donor (detailed below), preferably

Process and>

a ziegler natta main catalyst and an external donor used in the process.

Thus, a preferred multi-stage process may comprise the steps of:

producing a polypropylene random copolymer (PP-RACO) in a first slurry phase reactor and optionally a second slurry phase reactor in the presence of a selected catalyst system, for example as detailed below, the catalyst system comprising a specific Ziegler Natta procatalyst (i), an external donor (iii) and a cocatalyst (ii), both slurry phase reactors using the same polymerization conditions,

optionally transferring the product of the slurry phase reactor to at least one first gas phase reactor, such as one gas phase reactor or a first gas phase reactor and a second gas phase reactor in series,

-recovering the polymer product and further processing.

For the preferred slurry phase or slurry phase-gas phase processes described above, the following general information can be provided regarding the process conditions.

The temperature is preferably from 40 to 110 ℃, preferably between 50 and 100 ℃, in particular between 60 and 90 ℃, the pressure is in the range from 20 to 80bar, preferably from 30 to 60bar, and hydrogen is optionally added to control the molecular weight in a known manner.

The reaction product of the slurry phase polymerization, preferably carried out in a loop reactor, is then transferred to the subsequent gas phase reactor(s), at a temperature preferably ranging from 50 to 130 c, more preferably from 60 to 100 c, and at a pressure ranging from 5 to 50bar, preferably from 8 to 35bar, also optionally with the addition of hydrogen to control the molecular weight in a known manner.

The average residence time of the reaction zone determined above may vary. In one embodiment, the average residence time in the slurry phase reactor (e.g., loop reactor) is in the range of 0.5 to 5 hours, e.g., 0.5 to 2 hours, while the average residence time in the gas phase reactor is typically 1 to 8 hours.

If desired, the polymerization can be carried out under supercritical conditions in a slurry phase, preferably a loop reactor, and/or in a gas phase reactor in the condensed mode in a known manner.

According to the present invention, the polypropylene random copolymer (PP-RACO) is obtained by a polymerization process as described above in the presence of a catalytic system comprising the component (i) a Ziegler Natta procatalyst comprising the transesterification product of a lower alcohol and a phthalate.

The procatalyst used according to the invention is prepared by the following method:

a) Mixing MgCl ₂ And C ₁ -C ₂ Spray-or emulsion-solidified adducts of alcohols with TiCl ₄ The reaction is carried out in the presence of a catalyst,

b) At the C ₁ -C ₂ Reacting the product of step a) with a dialkyl phthalate of formula (I) under conditions such that an alcohol and said dialkyl phthalate of formula (I) are transesterified to form an internal donor,

/>

wherein R is ^1’ And R ^2’ Is independently at least C ₅ The alkyl group of (a) is,

c) Washing the product of step b), or

d) Optionally, the product of step c) is mixed with additional TiCl ₄ And (4) reacting.

The procatalyst is produced as described, for example, in patent application Nos. WO 87/07620, WO92/19653, WO 92/19658 and EP 0 491 566. The contents of these documents are incorporated herein by reference.

First, mgCl is formed ₂ And C ₁ -C ₂ Adducts of alcohols (of the formula MgCl) ₂ * nROH) where R is methyl or ethyl and n is 1 to 6. Ethanol is preferably used as the alcohol.

The adduct is first melted and then spray crystallized or emulsion solidified as a catalyst support.

Next, the compound of formula MgCl ₂ * Spray-or emulsion-solidified adducts of nROH, where R is methyl or ethyl, preferably ethyl, and n is 1 to 6, with TiCl ₄ Contacting to form a titanized support followed by the steps of:

adding to the titanized support, forming a first product:

(i) A dialkyl phthalate of the formula (I) wherein R ^1’ And R ^2’ Is independently at least C ₅ Alkyl of, e.g. at least C ₈ The alkyl group of (a) is,

or preferably, the amount of the water to be used,

(ii) A dialkyl phthalate of the formula (I) wherein R ^1’ And R ^2’ Is the same at least C ₅ Alkyl of, e.g. at least C ₈ The alkyl group of (a) is,

or more preferably still, the (c) is,

(iii) Dialkyl phthalates of the formula (I) selected from propylhexyl phthalate (PrHP), dioctyl phthalate (DOP), diisodecyl phthalate (DIDP) and tricosyl phthalate (DTDP), still more preferred dialkyl phthalates of the formula (I) are dioctyl phthalates (DOP), for example diisooctyl phthalate or diethylhexyl phthalate, in particular diethylhexyl phthalate.

Subjecting the first product to suitable transesterification reaction conditions, i.e. a temperature of more than 100 ℃, preferably between 100 and 150 ℃, more preferably between 130 and 150 ℃, whereby the methanol or ethanol transesterifies with the ester groups of the dialkyl phthalate of formula (I) to form preferably at least 80mol%, more preferably 90mol%, most preferably 95mol% of the dialkyl phthalate of formula (II):

wherein R is ¹ And R ² Is a methyl or ethyl group, preferably an ethyl group,

a dialkyl phthalate of the formula (II) as internal donor, and

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

In a preferred embodiment, there is MgCl ₂ * The adduct of nROH, where R is methyl or ethyl and n is 1 to 6, is melted and the melt is then injected, preferably by means of a gas, into a cooled liquid or cooled gas, whereby the adduct crystallizes into a morphologically advantageous form, as described for example in WO 87/07620. The crystalline adduct is preferably used as a catalyst support and reacted with a procatalyst useful in the present invention as described in WO 92/19658 and WO 92/19653.

When the catalyst residue is removed by extraction, an adduct of the titanized support and the internal donor is obtained in which the group derived from the ester alcohol has been changed.

If enough titanium remains on the support, it will act as the active element of the procatalyst.

Otherwise, the titanation is repeated after the above treatment to ensure a sufficient titanium concentration and thus activity.

Preferably, the procatalyst used according to the invention contains titanium in an amount of at most 2.5wt%, preferably at most 2.2wt%, more preferably at most 2.0wt%. The donor content thereof is preferably 4 to 12wt%, more preferably 6 to 10wt%.

More preferably, the cocatalyst used in the present invention is produced by using ethanol as alcohol and Dioctyl Phthalate (DPO) as dialkyl phthalate of formula (I), obtaining diethyl phthalate (DEP) as internal donor compound.

In a preferred embodiment, the procatalyst is obtained by emulsion technology developed in northern europe. Reference is made in this respect 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 the group 2 metal with the 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 any group 4-6 transition metal to prepare an emulsion, wherein the dispersed phase of the emulsion comprises greater than 50mol% of a group 2 metal in said complex;

c) Stirring the emulsion, optionally in the presence of an emulsion stabilizer, to maintain the droplets of the dispersed phase in a suitable average particle size range of from 5 to 200 μm, preferably from 10 to 100 μm, even more preferably from 20 to 50 μm;

d) Solidifying the droplets in the dispersed phase; and

e) Recovering the solidified particles of the obtained olefin polymerization catalyst.

The group 2 metal used in the preparation of the procatalyst according to the emulsion technique is preferably magnesium and the organic liquid medium used for reacting the group 2 metal compound preferably comprises C ₆ -C ₁₀ An aromatic hydrocarbon, preferably toluene. The electron donor compound reacted with the group 2 metal compound is preferably a mono-or diester of an aromatic carboxylic acid or diacid, the latter being capable of forming a chelate-like structural complex. The aromatic carboxylic acid ester or diester can be prepared by reacting an aromatic carboxylic acid chloride or diacid dichloride with C ₂ -C ₁₆ The alkanol and/or diol are formed in situ and are preferably dioctyl phthalate or bis- (2-ethylhexyl) phthalate. Preparation of group 2 metalsThe reaction of the complex is generally carried out at a temperature of from 20 to 80 ℃ and, in the case where the group 2 metal is magnesium, the preparation of the magnesium complex may advantageously be carried out at a temperature of from 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 the compound reacting with the complex of the group 2 metal is preferably a halide. In another embodiment of the invention, the compound of group 4-6 metals may also be selected from group 5 and 6 metals, such as Cu, fe, co, ni and/or Pd compounds. In a preferred embodiment of the catalyst production process, a Turbulence Minimizing Agent (TMA) is added to the reaction mixture before solidifying the particles of the dispersed phase, the TMA being inert and soluble in the reaction mixture under the reaction conditions. The Turbulence Minimizing Agent (TMA) or mixture thereof is preferably a polymer with a straight aliphatic carbon backbone, which may be branched with only short side chains in order to obtain uniform flow conditions upon stirring. The TMA is particularly preferably selected from those having a molecular weight of about 1 to 40X 10 ⁶ Or a high molecular weight Mw (as measured by gel permeation chromatography) of the alpha-olefin polymer of (a), or mixtures thereof. Particularly preferred are polymers of alpha-olefin monomers having 6 to 20 carbon atoms, more preferred are polyoctene, polynonyl, polydecene, polyundecene or polydodecene or mixtures thereof, the molecular weight and general framework structure of which are as defined above, and most preferred is that TMA is polydecene. In general, the turbulence minimizing agent may be added at any process step prior to the onset of particle formation, i.e., at the latest prior to solidification of the emulsion, and from 1 to 1000ppm, preferably from 5 to 100ppm, more preferably from 5 to 50ppm, of the turbulence minimizing agent may be added to the emulsion, based on the total weight of the reaction mixture. A preferred embodiment of the present invention obtains the procatalyst by: by including a magnesium alkoxide compound and an electron donor or its precursor in the composition containing C ₆ -C ₁₀ C of aromatic hydrocarbons ₆ -C ₁₀ Aromatic liquid reaction medium or C ₆ -C ₁₀ Aromatic hydrocarbons and C ₅ -C ₉ Reacting in a mixture of aliphatic hydrocarbons to prepare a solution of magnesium complex; reacting the magnesium complex with at least one tetravalent group 4 metal at a temperature greater than 10 ℃ and less than 60 ℃To produce more dense TiCl ₄ An emulsion of a toluene-insoluble oil-dispersed phase having a group 4 metal/magnesium molar ratio of 0.1 to 10 in an oil-dispersed phase having a group 4 metal/magnesium molar ratio of 10 to 100; maintaining the droplets of the dispersed phase in the size range of 5 to 200 μm by stirring in the presence of an emulsion stabilizer while heating the emulsion to solidify the droplets and adding a turbulence minimizing agent to the reaction mixture prior to solidifying the droplets of the dispersed phase, the turbulence minimizing agent being inert under reaction conditions and soluble in the reaction mixture; solidifying the dispersed phase particles by heating and recovering the obtained catalyst particles. The dispersion and the dispersed phase therefore differ from one another in that the denser oil does not dissolve in the solution of titanium tetrachloride in toluene if it comes into contact with it. Suitable TiCl meeting this criterion ₄ /toluene solution is TiCl ₄ A solution having a/toluene molar ratio of 0.1 to 0.3. The dispersion and the dispersed phase are also distinguished by the presence in the dispersed phase of a substantial amount of Mg (as a complex) which reacts with the group 4 metal compound, as revealed by comparison of the respective group 4 metal/magnesium molar ratios. Thus, in practice, the entire reaction product of the Mg complex and the group 4 metal, which is the precursor of the final catalyst, becomes the dispersed phase and is processed through further processing steps to ultimately form the final dry particulate form. While the dispersed phase, still containing useful amounts of group 4 metals, can be reprocessed to recover the metals. The production of a biphasic rather than a unidirectional reaction product is facilitated by carrying out the reaction of Mg complex/group 4 metal compound at low temperature, in particular above 10 ℃ and below 60 ℃, preferably between 20 ℃ and 50 ℃. Since the two phases will naturally tend to separate into a lower, denser phase and a lighter supernatant phase, it is necessary to maintain the reaction product as an emulsion by stirring, preferably in the presence of an emulsion stabilizer. The particles obtained from the dispersed phase of the emulsion have a size, shape (spherical) and homogeneity that make the final catalyst particularly effective in olefin polymerization. This morphology is retained when the particles are heat cured and is of course retained during the final washing and drying steps. In contrast, it is not necessary to provide a separate control unitThis morphology is difficult to achieve by precipitation due to the substantial uncontrollable nature of nucleation and growth and the large number of variables that affect these events. The electron donor is preferably an aromatic carboxylic acid ester, particularly preferred esters are dioctyl phthalate and bis- (2-ethylhexyl) phthalate. The donor may conveniently be prepared by reacting an aromatic carboxylic acid chloride precursor with C ₂ -C ₁₆ Formed in situ by reaction of an alkanol and/or diol. The liquid reaction medium preferably comprises toluene. Additionally, emulsifiers/emulsion stabilizers may additionally be used in a manner known in the art to facilitate the formation and/or stability of the emulsion. For the above purpose, for example, surfactants such as those based on acrylic or methacrylic polymers may be used. Preferably, the emulsion stabilizer is an acrylic or methacrylic polymer, particularly those having medium-sized ester side chains having greater than 10, preferably greater than 12 carbon atoms and preferably less than 30, preferably 12 to 20 carbon atoms in the ester side chain. Particularly preferred is unbranched C ₁₂ -C ₂₀ Acrylates, for example poly (hexadecyl) -methacrylate and poly (octadecyl) -methacrylate. It has been found that best results are obtained when the dense oil has a group 4 metal/Mg molar ratio of from 1 to 5, preferably from 2 to 4, and the dispersed phase oil has a group 4 metal/Mg molar ratio of from 55 to 65. Typically, the ratio between the molar ratio of group 4 metal/Mg in the dispersed phase oil and the molar ratio of group 4 metal/Mg in the dense oil is at least 10. Suitable temperatures for solidifying the dispersed phase droplets by heating are from 70 to 150 c, typically from 90 to 110 c.

The average size of the desired particulate form of the finally obtained procatalyst is in the range of 5 to 200. Mu.m, preferably 10 to 100. Mu.m, more preferably 20 to 50 μm. The reagents may be added to the aromatic reaction medium in any order. Preferably, however, in the first step, the carboxylic acid halide precursor of the electron donor is reacted with the magnesium alkoxide compound to form an intermediate; in the second step, the obtained product is further reacted with a group 4 metal. The magnesium compound preferably contains 1 to 20 carbon atoms per alkoxy group and the carboxylic acid should contain at least 8 carbon atoms. The reaction of the magnesium compound, the carboxylic acid halide and the alcohol may be satisfactorily carried out at a temperature of 20 to 80 c, preferably 50 to 70 c. The product of this reaction, the "magnesium complex", reacts with the group 4 metal compound at a lower temperature to form a two-phase oil-in-oil product. The reaction medium used as solvent may be an aromatic hydrocarbon or a mixture of an aromatic hydrocarbon and an aliphatic hydrocarbon, the latter containing preferably from 5 to 9 carbon atoms, more preferably from 5 to 7 carbon atoms or mixtures thereof. Preferably, the liquid reaction medium used as solvent is aromatic and more preferably selected from hydrocarbons, such as substituted and unsubstituted benzene, preferably from alkylated benzenes, even more preferably from toluene and xylene, most preferably toluene. The molar ratio of the aromatic medium to magnesium is preferably less than 10, for example from 4 to 10, preferably from 5 to 9. The magnesium alkoxide compound is preferably selected from the group consisting of magnesium dialkoxide, a complex of magnesium dihalide and alcohol, and a complex of magnesium dihalide and magnesium dialkoxide. It may be the reaction product of an alcohol with a magnesium compound selected from the group consisting of dialkyl magnesium, alkyl magnesium alkoxides, alkyl magnesium halides and magnesium dihalides.

It may also be selected from dialkoxymagnesium, diaryloxymagnesium, alkoxymagnesium halide, aryloxymagnesium halide, alkylmagnesium alkoxide, arylmagnesium alkoxide, and alkylmagnesium aryloxide. The magnesium dialkoxide may be the reaction product of a magnesium dihalide such as magnesium dichloride or a magnesium dialkyl of the formula R 'xR "yMg, where x + y =2, and x and y are in the range of 0.3 to 1.7, and each of R' and R" is a similar or different C ₁ -C ₂₀ Alkyl, preferably similar or different C ₄ -C ₁₀ An alkyl group. Typical alkyl magnesium are ethylbutyl magnesium, dibutyl magnesium, dipropyl magnesium, propylbutyl magnesium, diamyl magnesium, butylpentylgagnesium, butyloctyl magnesium and dioctylmagnesium. Preferably, R 'is butyl and R' is octyl, i.e. the dialkylmagnesium compound is butyloctylmagnesium, most preferably the dialkylmagnesium compound is Mg [ (Bu) _1.5 (Oct) _0.5 ]。

The magnesium dialkyl, alkyl magnesium alkoxide or dihalide may be reacted with a polyol R (OH) _m Reaction, where m ranges from 2 to 4, or with a monohydric alcohol ROH or mixtures thereof. Typical C ₂ To C ₆ The polyol of (a) may be a linear or branched alcohol, including: ethylene glycol, propylene glycol, trimethylene glycol, 1,2Butanediol, 1, 3-butanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 8-octanediol, pinacol (pinacol), diethylene glycol, triethylene glycol and triols, such as glycerol, trimethylolpropane (methyl propane) and pentaerythritol. The aromatic reaction medium may also comprise a linear or branched monoalcohol. Typical C ₁ -C ₅ Monohydric alcohols are methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol (sec. Butanol), tert-butanol, n-pentanol, isopentanol, sec-pentanol, tert-pentanol, diethylmethanol, neopentyl alcohol (akt. Amyl alcohol), sec-isoamyl alcohol, tert-butylmethanol. Typical of C ₆ -C ₁₀ The monohydric alcohol is hexanol, 2-ethyl-1-butanol, 4-methyl-2-pentanol, 1-heptanol, 2-heptanol, 4-heptanol, 2, 4-dimethyl-3-pentanol, 1-octanol, 2-ethyl-1-hexanol, 1-nonanol, 5-nonanol, diisobutylcarbinol, 1-decanol, and 2, 7-dimethyl-2-octanol. Typically, a>C ₁₀ The monohydric alcohol is 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 poison the catalyst. Preferred monoalcohols are those of the formula ROH, wherein R is C ₂ -C ₁₆ Alkyl, most preferably C ₄ -C ₁₂ Alkyl radicals, in particular 2-ethyl-1-hexanol or 1-octanol.

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

The compound of a tetravalent group 4 metal containing a halogen is preferably titanium tetrachloride. An equivalent of a titanium tetrahalide is a combination of an alkoxy titanium halide and a halogenating agent, which can form the titanium tetrahalide in situ. The most preferred halide is chloride.

It is well known that the addition of at least one halogenated hydrocarbon during the main catalyst preparation process can further improve the catalyst activity. The reactive halogenated hydrocarbon is preferably of formula R '"X"' _n Wherein R' "is C ₁ -C ₂₀ A hydrocarbon group,in particular C ₁ -C ₁₀ An aliphatic hydrocarbon 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) -trichloroethane, (1, 2) -tetrachloroethane, (1, 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 hydrocarbon may also be unsaturated, provided that the unsaturation does not cause catalyst poisoning in the final catalyst.

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

The preparation of the catalyst herein can be carried out batchwise, semi-continuously or continuously. In a semi-continuous or continuous process, a solution of a complex of group 2 and the electron donor, prepared by reacting a compound of the metal with the electron donor in an organic liquid reaction medium, is mixed with at least one transition metal compound, which is soluble in the same or a different organic liquid reaction medium. The solution thus obtained may then be stirred in the presence of an emulsion stabilizer, and the stirred emulsion is then fed to a temperature gradient reactor, where the emulsion is subjected to a temperature gradient, thereby solidifying the droplets in the dispersed phase of the emulsion. TMA preferably comprises adding TMA to the complex solution or prior to feeding the stirred solution to the temperature gradient reactor.

When the stirred emulsion is fed to the temperature gradient reactor, an inert solvent in which the liquid droplets are insoluble may be additionally added to the gradient reactor to improve the formation of the liquid droplets and thus to make the catalyst particles having a uniform particle size, the catalyst particles being formed in the temperature gradient reactor as the emulsion passes through the wire. This additional solvent may be the same as the organic liquid reaction medium used to prepare the group 2 complex solution as detailed above.

The solidified particles of catalyst may then be recovered by in-stream filtration units and preferably washed to remove unreacted initial components.

The recovered particulate product is washed at least once, preferably at least twice, most preferably at least three times with a hydrocarbon, preferably selected from aromatic and aliphatic hydrocarbons, preferably toluene, especially hot (e.g. 90 ℃) toluene, which may contain TiCl in a preferably small amount of about 0.01-10 vol.% ₄ Or an alkyl aluminium chloride, such as diethyl aluminium chloride (DEAC). Advantageously, the further washing may be carried out using heptane, most preferably hot heptane (e.g. 90 ℃), even more preferably pentane. The washing step typically comprises a plurality of sub-steps. A preferred washing sequence is, for example, one washing step with 90 ℃ toluene, two washing steps with 90 ℃ heptane and more than one washing step with pentane at room temperature.

Finally, the washed catalyst is dried, for example by evaporation or nitrogen flushing.

The catalyst system used according to the invention also comprises a cocatalyst, preferably an alkylaluminum compound as defined in detail below. In the case of procatalysts produced by emulsion technology, the cocatalyst is added (in neat form or in solution) shortly before the start of emulsion formation until it is added to the wash liquor, e.g. toluene. The amount of cocatalyst is such that the final Al content of the particle is from 0.05 to 1wt%, preferably from 0.1 to 0.8wt%, most preferably from 0.2 to 0.7wt%, based on the weight of the final catalyst particle. The most preferable content of Al varies depending on the type of Al compound and the addition step, and for example, in some cases, the most preferable content is 0.1 to 0.4wt%.

In a further embodiment, the ziegler-natta main catalyst may be modified by polymerizing a vinylic compound in the presence of a catalyst system comprising a specific ziegler-natta main catalyst, an external donor and a cocatalyst, wherein the vinylic compound has the formula:

CH ₂ ＝CH-CHR ³ R ⁴

wherein R is ³ And R ⁴ Together forming a 5-or 6-membered saturated, unsaturated or aromatic ring or independently representing an alkyl group comprising 1 to 4 carbon atoms, the modified catalyst is used to prepare the polypropylene random copolymer (PP-RACO) of the present invention. The polymerized vinyl compound acts as an alpha-nucleating agent.

References to catalyst modification for the reaction conditions of catalyst modification and for the polymerization reaction are to WO 99/24478, WO 99/24479 and in particular WO 00/68315, which are hereby incorporated by reference.

As mentioned above, for the preparation of the polypropylene random copolymer (PP-RACO) of the present invention, the catalyst system employed preferably comprises, as component (ii), in addition to the specific Ziegler Natta main catalyst, an organometallic co-catalyst.

Thus, it is preferred that the cocatalyst is selected from trialkylaluminums, such as Triethylaluminum (TEA), dialkylaluminum chlorides and alkylaluminum sesquichlorides.

Component (III) of the catalyst system used is an external donor represented by formula (III):

Si(OCH ₃ ) ₂ R ₂ ⁵ (III)

wherein R is ⁵ Represents a branched alkyl group of 3 to 12 carbon atoms, preferably a branched alkyl group of 3 to 6 carbon atoms, or a cycloalkyl group of 4 to 12 carbon atoms, preferably a cycloalkyl group of 5 to 8 carbon atoms.

Particularly preferred is R ⁵ Selected from the group consisting of isopropyl, isobutyl, isopentyl, tert-butyl, tert-pentyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

More specific examples of the hydrocarbyloxysilane compound as the external electron donor in the present invention are: diphenyldimethoxysilane, dicyclopentyldimethoxysilane (D-donor), dicyclopentyldiethoxysilane, cyclopentylmethyldimethoxysilane, cyclopentylmethyldiethoxysilane, dicyclohexyldimethoxysilane, dicyclohexyldiethoxysilane, cyclohexylmethyldimethoxysilane (C-donor), cyclohexylmethyldiethoxysilane, methylphenyldimethoxysilane, diphenyldiethoxysilane, cyclopentyltrimethoxysilane, phenyltrimethoxysilane, cyclopentyltriethoxysilane, phenyltriethoxysilane. Most preferably, the organosilane compound is diethylaminotriethoxysilane (U-donor), cyclohexylmethyldimethoxysilane (C-donor) or dicyclopentyldimethoxysilane (D-donor), the latter being particularly preferred.

The additives as indicated above were then added to the polypropylene random copolymer (PP-RACO) collected from the final reactor of the polymer production process. Preferably, these additives are mixed with the polypropylene random copolymer (PP-RACO) during the extrusion process of the one-step mixing process. Alternatively, a masterbatch may be formed in which the polypropylene random copolymer (PP-RACO) is first mixed with only a portion of the additives.

Comprising ethylene and/or C produced by the above process ₄ -C ₈ The properties of the polypropylene random copolymer of alpha-olefins (PP-RACO) can be adjusted and controlled by process conditions 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 in the multimodal polymer.

For mixing the individual components of the fiber-reinforced composition according to the invention, conventional mixing or blending equipment can be used, for example a Banbury mixer, a two-roll rubber mill, a Buss-co-kneader or a twin-screw extruder. Preferably, the mixing is accomplished in a co-rotating twin screw extruder. The polymeric material recovered from the extruder is typically in the form of pellets. These pellets are then preferably further processed, for example by compression molding, to produce articles and products of the fiber reinforced composition of the present invention.

Fiber Reinforced Composition (FRC)

An essential component of the fiber reinforced polypropylene composition (FRC) is the polypropylene composition (PP). The polypropylene composition (PP) is part of the polymer matrix of a fiber reinforced composition (FRP) in which the fibers (F) are embedded as reinforcing structure.

Preferably, the total amount of the polypropylene composition (PP) and the fibers (F) is at least 90 wt. -%, more preferably at least 95%, based on the total weight of the Fiber Reinforced Composition (FRC). In a most preferred embodiment, the polymer matrix of the fiber reinforced polypropylene composition (FRP) consists of the polypropylene composition (PP) and the fibers (F). In other words, in the most preferred embodiment, the fiber reinforced composition (FRP) is formed from only two components: the first component is a polypropylene composition (PP) to form a polymer matrix of a fiber reinforced composition (FRP) and the second component is fibers (F) embedded in the polymer matrix.

It is also preferred that the polymer matrix of the fiber reinforced composition (FRP) comprising the polypropylene composition (PP) is single-phase. In other words, the polypropylene composition (PP) which is part of or completely forms the matrix of the fiber-reinforced composition (FRP) comprises not more than one phase. In other words, the polypropylene composition (PP) is neither a heterophasic propylene copolymer nor comprises an additional elastomeric phase intended to modify the mechanical properties in some way.

The polypropylene composition (PP) is preferably present in the fiber-reinforced composition (FRP) in an amount of from 50 to 90 wt. -%, more preferably from 60 to 88 wt. -%, even more preferably from 70 to 86 wt. -%, and most preferably from 75 to 84 wt. -%, based on the total weight of the fiber-reinforced composition (FRC).

The content of the fibers (F) in the fiber-reinforced composition (FRC) is preferably from 10 to 50 wt. -%, more preferably from 12 to 40 wt. -%, even more preferably from 14 to 30 wt. -%, most preferably from 16 to 25 wt. -%, based on the total weight of the fiber-reinforced composition (FRC).

In one embodiment, the fibers (F) are individually dispersed in the polymer matrix of the fiber reinforced composition (FRP).

The Fiber Reinforced Composition (FRC) is prepared by a process comprising the steps of (a) providing a polypropylene composition (PP), (b) adding fibers (F) to said polypropylene composition (PP) and mixing, and (c) extruding a mixture comprising said polypropylene (PP) and said fibers from an extruder obtaining the Fiber Reinforced Composition (FRC) in the form of a sheet or pellets, preferably a sheet.

In another embodiment, the exterior article of the vehicle, preferably the body cover, may be prepared by a long fiber thermoplastic direct molding process (D-LFT) which allows for a compression molding step directly after the step of extruding a sheet of the fiber reinforced composition by use of an extruder.

Fiber (F)

Another essential component of the Fiber Reinforced Composition (FRC) is fibers embedded in a polymer matrix comprising a polypropylene composition (PP).

Preferably, the fibers (F) are selected from glass fibers, metal fibers, mineral fibers, ceramic fibers, carbon fibers, polymer fibers, graphite fibers and mixtures thereof. Glass fibers are preferred, in particular, the fibers (F) are obtained from glass grit. This means that in a preferred embodiment, the preferred fibers are glass fibers. The fiber (F) is particularly preferably a Long Fiber (LF), i.e., a long fiber of glass fiber. The length of the long fibers is not limited. After being fed to the extruder, the long fibers are changed into short fibers by the screw of the extruder.

The average diameter of the fibers (F) used in the fiber-reinforced composition is preferably at least 10 μm, more preferably from 12 to 25 μm, more preferably from 14 to 20 μm.

The content of the fibers (F) in the fiber-reinforced composition (FRC) is preferably from 10 to 50wt%, more preferably from 12 to 40wt%, even more preferably from 14 to 30wt%, most preferably from 16 to 25wt%, based on the total weight of the fiber-reinforced composition (FRC). Thus, the polypropylene composition (PP) is preferably present in the Fiber Reinforced Composition (FRC) in an amount of from 50 to 90 wt. -%, more preferably from 60 to 88 wt. -%, even more preferably from 70 to 86 wt. -%, most preferably from 75 to 84 wt. -%, based on the total weight of the Fiber Reinforced Composition (FRC).

Vehicle article

The invention also relates to a vehicle article comprising a fibre-reinforced composition as defined above. The vehicle article is preferably a molded article.

The term "molded article" as used herein is intended to encompass articles produced by any conventional molding technique, including stretch molding, compression molding, or rotational molding. However, it is particularly preferred that the molded article is obtained by compression molding, i.e., that the molded vehicle article is a compression molded article.

The molded article may be a vehicle exterior or interior article. Preferred embodiments include molded articles such as door modules, seat structures, tailgates, armrests, roof structures, chassis beams, pedals, side trims, pedal assist devices, body panels, spoilers, instrument panels, and interior trims.

Particularly preferred molded vehicle articles are exterior vehicle articles. The term "exterior" means that the article is not part of the interior of the vehicle but is part of the exterior of the vehicle. Preferred exterior vehicle articles are selected from exterior vehicle parts such as body shields, side trims, pedal assist devices, body panels, and spoilers. A particularly preferred external vehicle article is a body cover.

Preferably, the vehicle article, i.e. the vehicle exterior article, comprises more than 80wt%, more preferably more than 90wt%, still more preferably more than 95wt%, still more preferably more than 99wt% of the Fiber Reinforced Composition (FRC), still more preferably consists of the Fiber Reinforced Composition (FRC).

In another aspect, the present invention relates to the use of said Fiber Reinforced Composition (FRC) as defined above comprising said polypropylene random copolymer (PP-RACO) as defined above for the manufacture of an automotive exterior article.

In view of the prior art, this use of the present invention is particular because it effectively replaces the propylene homopolymer (H-PP) partially with the polypropylene random copolymer (PP-RACO) relative to the same vehicle exterior article in which the propylene homopolymer (H-PP) is not at least partially replaced with the polypropylene random copolymer (PP-RACO), thereby producing a weight-reduced vehicle exterior article in a direct process for long fiber reinforced thermoplastics. This is particularly important considering that the inventors could further demonstrate that it is possible to partially replace propylene homopolymer (H-PP) with polypropylene random copolymer (PP-RACO) in automotive exterior articles, while such at least partial replacement does not unduly alter mechanical properties, such as stiffness and toughness.

The present invention will be described in more detail by the following examples.

Examples

1. Defining/measuring method

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

The density is determined according to ISO 1183-187. Sample preparation was done by compression moulding according to ISO 1872-2.

The melting temperature Tm and the crystallization temperature Tc are determined according to ISO 11357-3.

MFR ₂ (230 ℃) in accordance with ISO1133 (230 ℃,2.16kg load).

Quantification of comonomer content by FTIR spectroscopy

In the determination of the quantity by ¹³ C Nuclear Magnetic Resonance (NMR) spectroscopy after basic job calibration by methods known in the art, comonomer content was determined by fourier transform infrared spectroscopy (FTIR). The film was pressed to a thickness of 100-500 μm and the spectrum was recorded in transmission mode.

Specifically, the ethylene content of the polypropylene-co-ethylene copolymer was used at 720-722 and 730-733cm ^-1 The baseline corrected peak area of the quantitative band found. Quantitative results were obtained based on the reference film thickness.

Stretching the film amount; tensile strength; elongation at break; yield stress was determined according to ISO527-2 (crosshead speed =50mm/min;23 ℃) using injection moulded specimens (dog bone shape, 4mm thickness) as described in EN ISO 1873-2.

Charpy impact test: charpy (notched) impact strength (Charpy NIS/IS) according to ISO 179 2C at 23 ℃ and-25 ℃, using 80x10x4mm prepared according to ISO 294-1 ³ Injection molded rod test sample determination.

A bending strength; flexural modulus was determined according to ISO 178.

Xylene solubles (XCS, wt%): xylene Cold Soluble (XCS) content according to ISO16152; a first edition; 2005-07-01 was determined at 25 ℃.

Average fiber diameter: according to ISO 1888:2006 (E), method B,1000 microscope magnification determination.

2. Examples of the embodiments

The propylene compositions of inventive examples IE1 and IE2 and comparative example CE1 below were prepared by mixing on a co-rotating twin-screw extruder at a temperature range of 180 to 200 ℃ according to the formulation in table 1.

TABLE 1 Polypropylene composition (PP) blended with fiber used in inventive examples and comparative examples

Composition (I)	Unit of	IE1	IE2	CE1
					PP-RACO	wt％	70	70
H-PP-1	wt％	21.3	25.3	91.5
					H-PP-2	wt％	4
AP	w-％	2.5	2.5	2.5
					PP-H,GD,225	wt％	1	1	2.2
Irganox 1076	wt％	0.4	0.4
					dstdp	wt％			1.3
Irgafos 168	wt％	0.2	0.2	0.75
					Irganox 1010	wt％	0.4	0.4	0.75
Black CMB	wt％	0.2	0.2	1

PP-RACO Polypropylene random copolymer obtained by sequential polymerization Process as described below, the final MFR thereof ₂ (230 ℃,2.16 kg) of 70g/10min (ISO 1133), an ethylene content of about 3.6wt% and an XCS content of about 5.0 wt%; the catalyst for preparing PP-RACO is a self-loading Ziegler-Natta catalyst described in WO 2004/029112; triethylaluminum (TEAL) was used as cocatalyst; dicyclopentyldimethoxysilane is used as a donor;

H-PP-1 Boroughe commercial propylene homopolymer, MFR thereof ₂ 60g/10min (ISO 1133), a flexural modulus of 1750MPa (5 mm/min; ISO 178), a Charpy notched impact strength (23 ℃; ISO 179/1 eA) of 2.5kJ;

the commercially available propylene homopolymer "Methocene MF650Y" from H-PP-2 Lyondell Basell, the MFR of which ₂ (230 ℃,2.16 kg) 1800g/10min (ISO 1133-1), density 0.9g/cm ³ (ASTM D792)；

AP Exxon Mobil commercial maleic anhydride functionalized Polypropylene "TPPP8112", having MFR ₂ >80g/10min, the MAH content is 1.4mol%;

PP-H, GD225 propylene homopolymer carrier, in powder form, with a melting temperature of 160 ℃;

octadecyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate Irganox 1076 BASF SE (CAS number 2082-79-3), melt temperature 50 ℃;

dstdp distearylthiodipropionate (CAS number 211-750-5) having a melting temperature of 64 ℃;

tris (2, 4-di-tert-butylphenyl) phosphite from Irgafos 168 BASF SE (CAS number 31570-04-4), having a melting temperature of 182 ℃;

irganox 1010 from Irganox 1010 BASF SE;

a commercially available carbon Black masterbatch "CMB 520black 7-PE 30" of Black CMB QolorTech bv (the Netherlands) consisting of 30% by weight of Black pigment 7, 40% by weight of CaCO ₃ And 30% by weight of LDPE

TABLE 2 preparation of Polypropylene random copolymer by sequential polymerization (PP-RACO)

Loop reactor
			Properties of	Unit of
T	[℃]	70
			p	[bar]	55
t Stay for	[h]	0.8
			MFR	g/10min	70
XCS	wt％	4.0
			C 2	wt％	1.6
Gas phase reactor
			T	[℃]	80
p	[bar]	21
			t Stay	[h]	1.7
MFR	g/10min	70
			XCS	wt％	5.0
C 2	wt％	3.6
			Split-loop/GPR	[％]	45/55

C ₂ Ethylene content

Temperature in T reactor

pressure of p reactor

t _Stay Average residence time in the reactor

TABLE 3 additives for PP-RACO Polypropylene random copolymer

Additive agent	wt％
		PP-RACO	97.54
Irganox 1010	0.05
		Irgafos 168	0.05
Calcium stearate	0.05
		DMDBS	0.17
GMS95	0.14
		HC205TF	2.0

DMDBS 1,3;

GMS95 wt% Glycerol monostearate

HC205TF Low melt flow Rate propylene homopolymer having a melt flow rate (230 ℃,2.16 kg) of 4g/10min (ISO 1183) and a density of 905kg/m ³ (ISO 1183), commercially available in northern Europe;

TABLE 4 Process for compounding the Polypropylene compositions (PP) of the inventive examples in the extruder

The mixing process of comparative example CE1 was similar to the inventive example.

Based on the above formulations, IE1, IE2 and CE1 compositions were prepared and tested for their properties, with the results shown in table 5.

TABLE 5 Properties of inventive and comparative examples

Properties of	Standard of merit	Unit	IE1	IE2	CE1
						MFR 2 (230℃/2.16kg)	ISO 1133	g/10min	90	80	60
Tensile strength	ISO 527	MPa	30	31	33
						Bending strength	ISO 178	MPa	40	40	50
Flexural modulus	ISO 178	MPa	1250	1300	1500
						Charpy notched impact strength at 23 ℃	ISO 179	kJ/m 2	3.5	3.2	2.2

As an exterior part of a vehicle, a body cover was formed by a long fiber reinforced thermoplastic direct process, i.e., a polypropylene composition of IE1, IE2 and CE1 was mixed with 20wt% of glass fiber, and then extruded into a sheet by a twin-screw extruder, and the sheet was directly compression-molded in a compression molding machine. The mechanical properties of the obtained body shrouds were characterized and tested as shown below.

TABLE 6 Properties of test specimens of body covers of inventive examples and comparative examples

The above tests show that the polypropylene composition (PP) of the invention is based mainly on polypropylene random copolymer (PP-RACO) and can be used to prepare body shields with reduced weight and thickness by the long fiber reinforced thermoplastic direct process, compared to previous materials based on propylene homopolymers. Furthermore, as indicated by the increase in melt flow rate, flowability may also be increased while substantially maintaining a balance of mechanical properties.

Claims (17)

1. Polypropylene composition PP comprising:

(a) 60 to 85wt% of a polypropylene random copolymer PP-RACO comprising at least one member selected from ethylene and C ₄ To C ₈ Of an alpha-olefin of (a) or (b),

(b) 13.5 to 35wt% of at least one propylene homopolymer H-PP, and

(c) 1.3 to 5.0wt% of a tackifier AP, the tackifier AP being a polar modified polypropylene, and

(d) 0.2 to 5.0wt% of an additive,

wherein,

(i) The polypropylene composition PP has a melt flow Rate MFR measured according to ISO1133 at 230 ℃ ₂ Is 30 to 200g/10min,

(ii) Polypropylene random copolymer PP-RACO melt flow Rate MFR measured according to ISO1133 at 230 ℃ ₂ Is 20 to 180g/10 min;

wherein the polypropylene composition PP is monophasic.

2. Polypropylene composition PP according to claim 1, wherein the polypropylene random copolymer PP-RACO comprises 1.0 to 5.0wt% of ethylene and/or C ₄ To C ₈ Of alpha-olefins.

3. Polypropylene composition PP according to claim 1 or 2, wherein the polypropylene random copolymer PP-RACO has a xylene cold soluble content XCS of 2 to 20wt%, measured according to ISO 6427 at 23 ℃.

4. Polypropylene composition PP according to claim 1 or 2, wherein the polypropylene random copolymer PP-RACO has a melting temperature determined according to differential scanning calorimetry, DSC, of 145 to 160 ℃.

5. Polypropylene composition PP according to claim 1 or 2, wherein the at least one propylene homopolymer H-PP has a melt flow rate MFR measured according to ISO1133 at 230 ℃ ₂ Is 5 to 220g/10min.

6. Polypropylene composition PP according to claim 1 or 2, wherein the at least one propylene homopolymer H-PP has a tensile strength at yield measured according to ISO-527 of at least 30MPa.

7. Polypropylene composition PP according to claim 1 or 2, wherein the tackifier AP comprises a maleic anhydride grafted polypropylene.

8. Polypropylene composition PP according to claim 1 or 2, wherein the total amount of (a) the polypropylene random copolymer PP-RACO, (b) the at least one propylene homopolymer H-PP and (c) the tackifier AP being a polar modified polypropylene is at least 90 wt. -%, based on the total weight of the polypropylene composition PP.

9. Fiber reinforced composition FRC comprising a polymer matrix and fibers F embedded in the polymer matrix, wherein,

(a) The polymer matrix comprises the polypropylene composition PP according to any one of claims 1 to 8, and

(b) The fibers F are selected from the group consisting of glass fibers, metal fibers, mineral fibers, ceramic fibers, carbon fibers, polymer fibers, graphite fibers and mixtures thereof, and

(c) The polymer matrix is single phase.

10. The fiber reinforced composition FRC of claim 9, wherein the fibers F are glass fibers.

11. The fiber-reinforced composition FRC of claim 9 or 10, wherein the fiber-reinforced composition FRC comprises, based on the total weight of the fiber-reinforced composition:

(a) 50 to 90wt% of the polypropylene composition PP,

(b) 10 to 50wt% of the fiber F.

12. Direct process for the manufacture of a vehicle exterior part by compression moulding of a long fiber reinforced thermoplastic, wherein the process comprises the steps of:

(a) Providing a polypropylene composition PP according to any one of claims 1 to 8,

(b) Adding and mixing fibres F to said polypropylene composition PP, and

(c) Extruding a mixture comprising said polypropylene PP and said fibres from an extruder to obtain a sheet of a fibre-reinforced composition FRC, and

(d) The sheet is molded in a molding press to form the outer component.

13. An automotive article comprising the fiber reinforced composition FRC of any one of claims 9 to 11.

14. The vehicle article of claim 13, wherein the vehicle article is a molded article.

15. The vehicle article of claim 13 or 14, wherein the vehicle article is selected from a vehicle exterior component.

16. The vehicular article of claim 15, wherein the vehicular article is selected from the group consisting of a body cover, a side fascia, a pedal assist device, a body panel, and a spoiler.

17. Use of a fiber reinforced composition according to any one of claims 9 to 11 for the manufacture of an automotive exterior article, wherein the fiber reinforced composition comprises the polypropylene random copolymer PP-RACO of claims 1 to 8.