CN112996851A - Fiber reinforced polypropylene composition with high oil resistance - Google Patents

Abstract

The present invention relates to a fiber reinforced polypropylene composition (C) comprising a Propylene Polymer (PP) having a xylene solubles content XCS of equal to or below 5.0 wt. -%, a fiber (F) and an Adhesion Promoter (AP). Furthermore, the present invention relates to an injection molded article comprising said fiber reinforced polypropylene composition (C).

Description

Fiber reinforced polypropylene composition with high oil resistance

Technical Field

The present invention relates to a fiber reinforced polypropylene composition (C) comprising a Propylene Polymer (PP) having a xylene solubles content XCS of equal to or below 5.0 wt. -%, a fiber (F) and an Adhesion Promoter (AP). Furthermore, the present invention relates to an article comprising said fiber reinforced polypropylene composition (C).

Background

The excellent mechanical properties, in particular stiffness and strength, of fiber reinforced polypropylene compositions are highly evaluated in the automotive industry. In particular, increasing the fiber content results in increased stiffness and strength.

A widely used method to improve the impact properties of such compositions is to use heterophasic propylene copolymers as base resin. However, the oil resistance of fiber-reinforced compositions comprising multiphase systems is often unsatisfactory due to the presence of amorphous phases.

Accordingly, there is a need in the art for a fiber reinforced polypropylene composition that exhibits good oil resistance while maintaining a high level of mechanical properties.

Disclosure of Invention

It is therefore an object of the present invention to provide a fiber reinforced polypropylene composition having good oil resistance as well as high stiffness and high strength.

Accordingly, the present invention provides a fiber reinforced polypropylene composition (C) comprising:

i) propylene Polymers (PP) having a xylene solubles content XCS equal to or lower than 5.0 wt. -%,

ii) fibers (F), and

iii) an Adhesion Promoter (AP),

wherein the fiber reinforced polypropylene composition satisfies the inequality (I)

Wherein w (PP) is the weight fraction of the Propylene Polymer (PP) [ in wt% ], based on the total weight of the fiber-reinforced polypropylene composition (C), and w (AP) is the weight fraction of the Adhesion Promoter (AP) [ in wt% ], based on the total weight of the fiber-reinforced polypropylene composition (C).

According to one embodiment of the invention, the Propylene Polymer (PP) is monophasic.

According to another embodiment of the present invention, the fiber reinforced polypropylene composition (C) does not comprise a propylene polymer having a xylene solubles content XCS of more than 5.0 wt. -%.

According to another embodiment of the present invention, the fiber reinforced polypropylene composition (C) satisfies the inequality (II):

wherein w (F) is the weight fraction of the fibers (F) [ in wt% ], based on the total weight of the fiber-reinforced polypropylene composition (C), and w (AP) is the weight fraction of the Adhesion Promoter (AP) [ in wt% ], based on the total weight of the fiber-reinforced polypropylene composition (C).

According to another embodiment of the invention, the Propylene Polymer (PP) is at least bimodal.

It is particularly preferred that the Propylene Polymer (PP) is a propylene homopolymer (H-PP).

According to one embodiment of the invention, the Propylene Polymer (PP) comprises:

i) a first propylene polymer (PP1) having a melt flow rate MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂Is equal to or lower than 20g/10min, and

ii) an optional second propylene polymer (PP2) having a melt flow rate MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂Is greater than 20g/10 min.

According to another embodiment of the invention, the fibers (F) are Staple Fibers (SF).

Particularly preferably, the fibers (F) are Glass Fibers (GF), more preferably Short Glass Fibers (SGF).

Preferably, the Short Fibers (SF), more preferably the Short Glass Fibers (SGF), have:

i) an average length of 1.0 to 10.0mm, and/or

ii) an average diameter of 8 to 20 μm.

According to one embodiment of the invention, the Adhesion Promoter (AP) is a polar modified polypropylene (PM-PP), which is a propylene homopolymer or copolymer grafted with maleic anhydride and having a melt flow rate MFR, measured according to ISO 1133 at 190 ℃ and under a load of 2.16kg, of at least 80.0g/10 min.

According to another embodiment of the present invention, the fiber reinforced polypropylene composition (C) comprises, based on the total weight of the fiber reinforced polypropylene composition (C):

i) from 50.0 to 80.0% by weight of a Propylene Polymer (PP) having a xylene solubles content XCS equal to or lower than 5.0% by weight,

ii)15.0 to 40.0 wt% of fibres (F),

iii)3.0 to 10.0 wt.% of an Adhesion Promoter (AP), and

iv) optionally 0.1 to 4.0 wt.% of Additives (AD).

The present invention further provides an article comprising the above fiber reinforced polypropylene composition (C).

Preferably, the article comprises at least 90 wt% of the fiber reinforced polypropylene composition (C).

According to one embodiment of the invention, the article is an automotive article, preferably an automotive engine article.

Particularly preferably, the article is an intake manifold of an engine.

Hereinafter, the present invention will be described in more detail.

Detailed Description

Fiber-reinforced Polypropylene composition (C)

As mentioned above, the present invention provides a fiber reinforced polypropylene composition (C) comprising a Propylene Polymer (PP) having a xylene solubles content XCS of equal to or below 5.0 wt. -%, a fiber (F) and an Adhesion Promoter (AP).

The fiber reinforced polypropylene composition satisfies the inequality (I), preferably satisfies the inequality (Ia), more preferably satisfies the inequality (Ib):

wherein w (PP) is the weight fraction of the Propylene Polymer (PP) [ in wt% ], based on the total weight of the fiber-reinforced polypropylene composition (C), and w (AP) is the weight fraction of the Adhesion Promoter (AP) [ in wt% ], based on the total weight of the fiber-reinforced polypropylene composition (C).

In addition to or instead of the preceding paragraph, preferably the fiber reinforced polypropylene composition (C) satisfies the inequality (II), more preferably satisfies the inequality (IIa), still more preferably satisfies the inequality (IIb)

Wherein w (F) is the weight fraction of the fibers (F) [ in wt% ], based on the total weight of the fiber-reinforced polypropylene composition (C), and w (AP) is the weight fraction of the Adhesion Promoter (AP) [ in wt% ], based on the total weight of the fiber-reinforced polypropylene composition (C).

Preferably, the fiber reinforced polypropylene composition (C) comprises, based on the total weight of the fiber reinforced polypropylene composition (C):

i) from 50.0 to 80.0 wt%, more preferably from 53.0 to 75.0 wt%, still more preferably from 55.0 to 70.0 wt%, such as from 56.0 to 61.0 wt% of a Propylene Polymer (PP) having a xylene solubles content XCS equal to or lower than 5.0 wt%,

ii)15.0 to 40.0 wt.%, more preferably 20.0 to 38.0 wt.%, still more preferably 25.0 to 36.0 wt.%, such as 30.0 to 35.0 wt.% of fiber (F), and

iii)3.0 to 10.0 wt%, more preferably 3.2 to 8.0 wt%, still more preferably 3.5 to 6.0 wt%, such as 4.0 to 5.0 wt% of an Adhesion Promoter (AP).

Furthermore, the fiber reinforced polypropylene composition (C) may comprise an Additive (AD).

Accordingly, the fiber reinforced polypropylene composition (C) comprises, based on the total weight of the fiber reinforced polypropylene composition (C):

i) from 50.0 to 80.0 wt%, more preferably from 53.0 to 75.0 wt%, still more preferably from 55.0 to 70.0 wt%, such as from 56.0 to 61.0 wt% of a Propylene Polymer (PP) having a xylene solubles content XCS equal to or lower than 5.0 wt%,

ii)15.0 to 40.0 wt.%, more preferably 20.0 to 38.0 wt.%, still more preferably 25.0 to 36.0 wt.%, such as 30.0 to 35.0 wt.% of fibers (F),

iii)3.0 to 10.0 wt.%, more preferably 3.2 to 8.0 wt.%, still more preferably 3.5 to 6.0 wt.%, such as 4.0 to 5.0 wt.% of an Adhesion Promoter (AP), and

iv) optionally 0.1 to 4.0 wt%, more preferably 1.0 to 3.0 wt%, still more preferably 1.5 to 2.8 wt%, such as 2.0 to 2.6 wt% of Additive (AD).

As outlined in more detail below, Propylene Polymers (PP) having a xylene solubles content XCS of equal to or below 5.0 wt% may or may not be bimodal. Thus, the Propylene Polymer (PP) preferably comprises a first propylene polymer (PP1) and optionally a second propylene polymer (PP2) having a melt flow rate MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂Higher than the first propylene polymer (PP 1).

Accordingly, it is preferred that the fiber reinforced polypropylene composition (C) comprises, more preferably consists of, based on the total weight of the fiber reinforced polypropylene composition (C):

i)50.0 to 80.0 wt%, more preferably 51.0 to 70.0 wt%, still more preferably 53.0 to 65.0 wt%, such as 55.0 to 60.0 wt% of a first propylene polymer (PP1),

ii) optionally, 0.1 to 15.0 wt%, more preferably 1.0 to 10.0 wt%, still more preferably 1.5 to 5.0 wt%, such as 2.0 to 4.0 wt% of a second propylene polymer (PP2),

iii)15.0 to 40.0 wt.%, more preferably 20.0 to 38.0 wt.%, still more preferably 25.0 to 36.0 wt.%, such as 30.0 to 35.0 wt.% of fiber (F),

iv)3.0 to 10.0 wt.%, more preferably 3.2 to 8.0 wt.%, still more preferably 3.5 to 6.0 wt.%, such as 4.0 to 5.0 wt.% of an Adhesion Promoter (AP), and

v) optionally 0.1 to 4.0 wt%, more preferably 1.0 to 3.0 wt%, still more preferably 1.5 to 2.8 wt%, such as 2.0 to 2.6 wt% of Additive (AD).

As mentioned above, it is preferred that the fiber reinforced polypropylene composition (C) does not comprise any amorphous propylene polymer. In other words, it is preferred that the fiber reinforced polypropylene composition (C) does not comprise any propylene polymer having a xylene soluble content XCS of equal to or more than 5.0 wt. -%, more preferably does not comprise any propylene polymer having a xylene soluble content XCS of equal to or more than 3.0 wt. -%, more preferably does not comprise any propylene polymer having a xylene soluble content XCS of equal to or more than 2.3 wt. -%.

More preferably, the xylene solubles content XCS of the fiber reinforced polypropylene composition (C) is equal to or lower than 5.0 wt. -%, more preferably equal to or lower than 3.0 wt. -%, still more preferably equal to or lower than 2.3 wt. -%.

Further, preferably, the fiber reinforced polypropylene composition (C) has a melt flow rate MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂From 0.1 to 15.0g/10min, more preferably from 1.0 to 10.0g/10min, still more preferably in the range of from 2.0 to 8.0g/10min, such as in the range of from 3.0 to 5.0g/10 min.

Furthermore, preferably, the fiber reinforced polypropylene composition (C) is characterized by excellent mechanical properties. Therefore, it is preferred that the fiber reinforced polypropylene composition (C) has a tensile modulus as determined by ISO 527 of at least 3000MPa, more preferably 4000-.

As an addition or alternative to the preceding paragraph, preferably the fiber reinforced polypropylene composition (C) has a flexural modulus determined according to ISO 178 of at least 3000MPa, more preferably in the range of 4000 to 11000MPa, still more preferably in the range of 6000 to 10000MPa, for example in the range of 7000 to 9000 MPa.

In addition, it is preferred that the fiber reinforced polypropylene composition (C) has a tensile strength determined according to ISO 527 of at least 70MPa, more preferably of from 75 to 150MPa, even more preferably of from 90 to 140MPa, such as from 100 to 130 MPa.

As mentioned above, the fiber reinforced polypropylene composition (C) is characterized by a high resistance to oil. Accordingly, it is preferred that the fiber reinforced polypropylene composition (C) retains a high level of mechanical properties after exposure to oil.

In particular, it is preferred that the fiber reinforced polypropylene composition (C) satisfies the inequality (III),

wherein TS_R250Is the retention of tensile strength, TS, after immersion of the fiber-reinforced polypropylene composition (C) in oil for 250 hours₂₅₀Is the tensile strength [ MPa ] of the fiber reinforced polypropylene composition (C) after being immersed in oil for 250 hours]TS is the tensile strength [ MPa ] before immersion of the fiber-reinforced polypropylene composition (C) in oil]。

Further, the fiber-reinforced polypropylene composition (C) preferably satisfies the Inequality (IV),

wherein TS_R500Is the retention of tensile strength, TS, after immersion of the fiber-reinforced polypropylene composition (C) in oil for 500 hours₅₀₀Is the tensile strength [ MPa ] of the fiber reinforced polypropylene composition (C) after being immersed in oil for 500 hours]TS is the tensile strength [ MPa ] before immersion of the fiber-reinforced polypropylene composition (C) in oil]。

In addition or alternatively to the preceding paragraph, preferably the fiber reinforced polypropylene composition (C) satisfies the inequality (V),

wherein TS_R1000Is the retention of tensile strength, TS, after immersion of the fiber-reinforced polypropylene composition (C) in oil for 1000 hours₁₀₀₀Is the tensile strength [ MPa ] of the fiber reinforced polypropylene composition (C) after being immersed in oil for 1000 hours]TS is the tensile strength [ MPa ] before immersion of the fiber-reinforced polypropylene composition (C) in oil]。

In addition to the tensile strength, the tensile modulus of the fiber reinforced polypropylene composition (C) remains at a high level also after exposure to oil.

Therefore, it is preferred that the fiber reinforced polypropylene composition (C) satisfies the inequality (VI),

wherein, TM_R250Is the tensile modulus retention, TM, after immersion of the fiber-reinforced polypropylene composition (C) in oil for 250 hours₂₅₀Is the tensile modulus [ MPa ] of the fiber reinforced polypropylene composition (C) after being immersed in oil for 250 hours]TM is the tensile modulus [ MPa ] before immersion of the fiber-reinforced polypropylene composition (C) in oil]。

Further, the fiber-reinforced polypropylene composition (C) preferably satisfies the inequality (VII),

wherein, TM_R500Is the tensile modulus retention, TM, after immersion of the fiber-reinforced polypropylene composition (C) in oil for 500h₅₀₀Is a tensile modulus [ MPa ] of a fiber-reinforced polypropylene composition (C) after immersion in oil for 500 hours]TM is the tensile modulus [ MPa ] before immersion of the fiber-reinforced polypropylene composition (C) in oil]。

In addition to or as an alternative to the preceding paragraph, it is preferred that the fiber reinforced polypropylene composition (C) satisfies the inequality (VIII),

wherein, TM_R1000Is the tensile modulus retention, TM, after immersion of the fiber-reinforced polypropylene composition (C) in oil for 1000h₁₀₀₀Is the tensile modulus [ MPa ] of the fiber reinforced polypropylene composition (C) after being immersed in oil for 1000 hours]TM is the tensile modulus [ MPa ] before immersion of the fiber-reinforced polypropylene composition (C) in oil]。

Hereinafter, the Propylene Polymer (PP), the fiber (F) and the Adhesion Promoter (AP) are described in more detail.

Propylene Polymers (PP)

As mentioned above, the fiber reinforced polypropylene composition (C) comprises a Propylene Polymer (PP).

The Propylene Polymer (PP) may be a propylene copolymer or a propylene homopolymer, the latter being preferred.

In case the Propylene Polymer (PP) is a propylene copolymer, the Propylene Polymer (PP) comprises monomers copolymerizable with propylene, e.g. comonomers such as ethylene and/or C₄To C₈Alpha-olefins, in particular ethylene and/or C₄To C₆Alpha-olefins, such as ethylene, 1-butene and/or 1-hexene. Preferably, the Propylene Polymer (PP) according to the present invention comprises, in particular consists of, a monomer copolymerizable with propylene, said monomer being selected from ethylene, 1-butene and 1-hexene. More specifically, the Propylene Polymer (PP) of the present invention comprises, in addition to propylene, units derived from ethylene and/or 1-butene. In a preferred embodiment, the Propylene Polymer (PP) comprises only units derived from ethylene and propylene.

The comonomer content of the Propylene Polymer (PP) is in the range of 0.0 to 5.0 wt. -%, still more preferably in the range of 0.0 to 3.0 wt. -%, still more preferably in the range of 0.0 to 1.0 wt. -%.

It is particularly preferred that the Propylene Polymer (PP) is a propylene homopolymer (H-PP).

According to the present invention, the expression "propylene homopolymer" relates to a polypropylene consisting essentially of propylene units, for example a polypropylene consisting of at least 99.0 wt%, more preferably at least 99.5 wt%, still more preferably at least 99.8 wt%, such as at least 99.9 wt% propylene units. In another embodiment, only propylene units are detectable, i.e. only propylene has been polymerized.

Preferably, the Propylene Polymer (PP), such as propylene homopolymer (H-PP), is isotactic. Thus, Propylene Polymers (PP), such as propylene homopolymers (H-PP), are preferred, having a rather high pentad concentration (mmmm%), i.e. more than 94.1%, more preferably more than 94.4%, such as in the range of more than 94.4 to 98.5%, more preferably at least 94.7%, such as in the range of 94.7 to 98.5%.

Propylene Polymers (PP), such as propylene homopolymers (H-PP), are preferred, which are characterized by a rather low Xylene Cold Soluble (XCS) content, i.e. less than 3.1 wt% Xylene Cold Soluble (XCS). Thus, the Propylene Polymer (PP), such as a propylene homopolymer (H-PP), preferably has a Xylene Cold Soluble (XCS) content in the range of 1.0 to 3.0 wt. -%, more preferably in the range of 1.5 to 2.8 wt. -%, yet more preferably in the range of 2.0 to 2.6 wt. -%.

The amount of Xylene Cold Soluble (XCS) also indicates that the Propylene Polymer (PP), such as propylene homopolymer (H-PP), preferably does not contain any elastomeric polymer component, such as ethylene-propylene rubber. In other words, Propylene Polymers (PP), such as propylene homopolymers (H-PP), are not heterophasic polypropylenes, i.e. systems consisting of a polypropylene matrix in which an elastomeric phase is dispersed. Such systems are characterized by a rather high xylene cold soluble content.

The amount of Xylene Cold Soluble (XCS) also indicates that Propylene Polymers (PP), such as propylene homopolymers (H-PP), preferably free of inclusion-forming elastomeric (co) polymers, are used as second phase to improve mechanical properties. In contrast, polymers comprising an elastomeric (co) polymer as an interposed second phase will be referred to as heterophasic and are preferably not part of the present invention. The presence of second phases or so-called inclusions is visible, for example, by high resolution microscopy such as electron microscopy or atomic force microscopy or by Dynamic Mechanical Thermal Analysis (DMTA). In particular, in DMTA, the presence of a multiphase structure can be identified by the presence of at least two different glass transition temperatures.

Furthermore, the Propylene Polymer (PP), such as a propylene homopolymer (H-PP), is preferably a crystalline propylene homopolymer. The term "crystalline" means that Propylene Polymers (PP), such as propylene homopolymers (H-PP), have a rather high melting temperature. Thus, throughout the present invention, unless otherwise indicated, Propylene Polymers (PP), such as propylene homopolymers (H-PP), are considered crystalline. Thus, the Propylene Polymer (PP), such as a propylene homopolymer (H-PP), preferably has a melting temperature Tm, as measured by Differential Scanning Calorimetry (DSC), of at least 160 ℃, more preferably at least 161 ℃, still more preferably at least 163 ℃, such as in the range of 163 ℃ to 167 ℃.

Further, the Propylene Polymer (PP), such as a propylene homopolymer (H-PP), has a crystallization temperature Tc measured by Differential Scanning Calorimetry (DSC) of preferably equal to or greater than 108 ℃, more preferably in the range of 110 to 130 ℃, more preferably in the range of 120 to 130 ℃.

It will be appreciated that Propylene Polymers (PP) are characterized by a rather low melt flow rate. Thus, the preferred Propylene Polymers (PP) have a melt flow rate MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂Less than 50.0g/10min, more preferably in the range of 0.1 to 40.0g/10min, still more preferably in the range of 1.0 to 30.0g/10min, still more preferably in the range of 3.0 to 20.0g/10min, still more preferably in the range of 5.0 to 15.0g/10min, such as in the range of 6.0 to 10.0g/10 min.

According to a preferred embodiment of the present invention, the Propylene Polymer (PP) is preferably bimodal.

Thus, it is preferred that the Propylene Polymer (PP) comprises at least two propylene polymers. It is particularly preferred that the Propylene Polymer (PP) comprises two propylene polymers, namely a first propylene polymer (PP1) and a second propylene polymer (PP 2).

Preferably, the first propylene polymer (PP1) and the second propylene polymer (PP2) have a melt flow rate MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂Different.

The first propylene polymer (PP1) and the second propylene polymer (PP2) may be a propylene copolymer or a propylene homopolymer, respectively.

In case the first propylene polymer (PP1) and/or the second propylene polymer (PP2) is a propylene copolymer, said propylene polymer comprises monomers copolymerizable with propylene, e.g. comonomers such as ethylene and/or C₄To C₈Alpha-olefins, in particular ethylene and/or C₄To C₆Alpha-olefins, such as 1-butene and/or 1-hexene. Preferably, the first propylene polymer (PP1) and/or the second propylene polymer (PP2) according to the present invention comprises, in particular consists of, a monomer copolymerizable with propylene, said monomer being selected from ethylene, 1-butene and 1-hexene. More specifically, the first inventionThe propylene polymer (PP1) and/or the second propylene polymer (PP2) comprise, in addition to propylene, units derived from ethylene and/or 1-butene. In a preferred embodiment, the Propylene Polymer (PP) comprises only units derived from ethylene and propylene.

As outlined in more detail below, the first propylene polymer (PP1) may comprise a first propylene polymer fraction (PP1a) and a second propylene polymer fraction (PP1 b). Thus, in embodiments wherein the Propylene Polymer (PP) comprises only the first propylene polymer (PP1) and the first propylene polymer (PP1) comprises the first propylene polymer fraction (PP1a) and the second propylene polymer fraction (PP1b), the Propylene Polymer (PP) is also bimodal.

The comonomer content of the first propylene polymer (PP1) and/or the second propylene polymer (PP2) is in the range of 0.0 to 5.0 wt%, still more preferably in the range of 0.0 to 3.0 wt%, still more preferably in the range of 0.0 to 1.0 wt%, respectively.

However, as mentioned above, it is preferred that the Propylene Polymer (PP) is a propylene homopolymer (H-PP). Therefore, it is preferred that all propylene polymers of the Propylene Polymer (PP), i.e. the first propylene polymer (PP1) and the second propylene polymer (PP2), are propylene homopolymers. With regard to the expression "propylene homopolymer", reference is made to the definition provided above.

Hereinafter, the first propylene polymer (PP1) and the second propylene polymer (PP2) are described in more detail.

First propylene Polymer (PP1)

The first propylene polymer (PP1) preferably has a lower melt flow rate MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂. Thus, it is preferred that the first propylene polymer (PP1) has a melt flow rate MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂Is below 50.0g/10min, more preferably in the range of 0.1 to 40.0g/10min, still more preferably in the range of 1.0 to 30.0g/10min, still more preferably in the range of 3.0 to 20.0g/10min, more preferably in the range of 5.0 to 15.0g/10min, such as in the range of 6.0 to 10.0g/10 min.

Another characteristic of the first propylene polymer (PP1) is that it has a relatively small amount of internal faults in the polymer chainIntercalated propylene, which means that the first propylene polymer (PP1) is produced in the presence of a Ziegler-Natta catalyst, preferably a Ziegler-Natta catalyst (ZN-C1) as defined in more detail below. Therefore, the first propylene polymer (PP1) preferably has the following characteristics: by passing¹³A small amount of 2,1 erythro-type regio defects, i.e., equal to or less than 0.4 mol%, more preferably equal to or less than 0.2 mol%, such as not more than 0.1 mol%, as determined by C-NMR spectroscopy. In a particularly preferred embodiment, no 2,1 erythro-type region defects are detectable.

Preferably, the first propylene polymer (PP1) is characterized by a rather low Xylene Cold Soluble (XCS) content, i.e. less than 4.1 wt% Xylene Cold Soluble (XCS). Thus, the Xylene Cold Soluble (XCS) content of the first propylene polymer (PP1) is preferably in the range of 1.0 to 4.0 wt. -%, more preferably in the range of 1.0 to 2.0 wt. -%.

The amount of Xylene Cold Soluble (XCS) also indicates that the first propylene polymer (PP1) preferably does not contain any elastomeric polymer component, such as ethylene propylene rubber. In other words, the first propylene polymer (PP1) should not be a heterophasic polypropylene, i.e. a system consisting of a polypropylene matrix in which an elastomeric phase is dispersed. Such systems are characterized by a rather high xylene cold soluble content.

The amount of Xylene Cold Soluble (XCS) also indicates that the first propylene polymer (PP1) preferably does not contain inclusion-forming elastomeric (co) polymers as a second phase to improve mechanical properties. In contrast, polymers comprising an elastomeric (co) polymer as an interposed second phase will be referred to as heterophasic and are preferably not part of the present invention. The presence of second phases or so-called inclusions is visible, for example, by high resolution microscopy such as electron microscopy or atomic force microscopy or by Dynamic Mechanical Thermal Analysis (DMTA). In particular, in DMTA, the presence of a multiphase structure can be identified by the presence of at least two different glass transition temperatures.

Further, the first propylene polymer (PP1) is preferably a crystalline propylene homopolymer. The term "crystalline" means that the first propylene polymer (PP1) has a rather high melting temperature. Thus, throughout the present invention, the first propylene polymer (PP1) is considered crystalline unless otherwise indicated. Thus, the melting temperature Tm of the first propylene polymer (PP1) as measured by Differential Scanning Calorimetry (DSC) is preferably at least 158 ℃, more preferably at least 160 ℃, still more preferably at least 161 ℃, such as in the range of 161 ℃ to 168 ℃.

Further, preferably, the first propylene polymer (PP1) has a crystallization temperature Tc as measured by Differential Scanning Calorimetry (DSC) equal to or greater than 110 ℃, more preferably in the range of 110 to 140 ℃, more preferably in the range of 120 to 130 ℃.

According to a preferred embodiment of the invention, the first propylene polymer (PP1) is bimodal.

Thus, it is preferred that the first propylene polymer (PP1) comprises at least two propylene polymer fractions. Especially preferably, the first propylene polymer (PP1) comprises two propylene polymer fractions, a first propylene polymer fraction (PP1a) and a second propylene polymer fraction (PP1 b).

Preferably, the first propylene polymer fraction (PP1a) and the second propylene polymer fraction (PP1b) have different melt flow rates MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂And/or different comonomer content.

The first propylene polymer fraction (PP1a) and the second propylene polymer fraction (PP1b) may be a propylene copolymer or a propylene homopolymer, respectively.

If the first propylene polymer fraction (PP1a) and/or the second propylene polymer fraction (PP1b) is a propylene copolymer, the propylene polymer comprises monomers copolymerizable with propylene, e.g. comonomers, such as ethylene and/or C₄To C₈Alpha-olefins, in particular ethylene and/or C₄To C₆For example 1-butene and/or 1-hexene. Preferably, the first propylene polymer fraction (PP1a) and/or the second propylene polymer fraction (PP1b) according to the present invention comprises, in particular consists of, a monomer copolymerizable with propylene, selected from ethylene, 1-butene and 1-hexene. More specifically, the first propylene polymer fraction of the present invention: (PP1a) and/or the second propylene polymer fraction (PP1b) comprise units derived from ethylene and/or 1-butene in addition to propylene. In a preferred embodiment, the first propylene polymer (PP1) comprises only units derived from ethylene and propylene.

Preferably, the first propylene polymer (PP1) is nucleated, more preferably alpha-nucleated. Thus, it is preferred that the first propylene polymer (PP1) is prepared in the presence of a nucleating agent, preferably an alpha-nucleating agent.

In case the first propylene polymer (PP1) comprises an alpha nucleating agent, it is preferably free of a beta nucleating agent. The alpha nucleating agent is preferably selected from the following:

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

(ii) dibenzylidene sorbitol (e.g. 1, 3: 2,4 dibenzylidene sorbitol) and C₁-C₈Alkyl-substituted dibenzylidene sorbitol derivatives, such as methyl dibenzylidene sorbitol, ethyl dibenzylidene sorbitol or dimethyl dibenzylidene sorbitol (e.g. 1, 3: 2,4 di (methylbenzylidene) sorbitol), or substituted nonanol derivatives, such as 1,2,3, -trideoxy-4, 6: 5, 7-bis-O- [ (4-propylphenyl) methylene]-nonanol, and

(iii) salts of diesters of phosphoric acid, for example sodium 2,2 '-methylenebis (4, 6-di-tert-butylphenyl) phosphate or aluminum hydroxy-bis [2,2' -methylene-bis (4, 6-di-tert-butylphenyl) phosphate ], and

(iv) polymers of vinylcycloalkanes and vinylalkane polymers (as discussed in more detail below), and

(v) mixtures thereof.

Such Additives are generally commercially available and are described, for example, in "plastics Additives Handbook" from Hans Zweifel, pages 871 to 873, 5 th edition, 2001.

Preferably, the first propylene polymer (PP1) comprises at most 5.0 wt% of an alpha-nucleating agent. In a preferred embodiment, the propylene homopolymer comprises not more than 500ppm, more preferably from 0.025 to 200ppm, more preferably from 0.1 to 200ppm, still more preferably from 0.3 to 200ppm, most preferably from 0.3 to 100ppm of an alpha nucleating agent, in particular selected from dibenzylidene sorbitol (e.g. 1, 3: 2,4 dibenzylidene sorbitol), dibenzylidene sorbitol derivatives, preferably dimethyl dibenzylidene sorbitol (e.g. 1, 3: 2,4 di (methylbenzylidene) sorbitol) or substituted nonanol derivatives, such as 1,2,3, -triseoxy-4, 6: 5, 7-bis-O- [ (4-propylphenyl) methylene ] -nonanol, sodium 2,2' -methylenebis (4,6, -di-tert-butylphenyl) phosphate, polymers of vinylcycloalkanes, polymers of vinylalkanes and mixtures thereof.

Preferably, the first propylene polymer (PP1) is obtained by polymerizing propylene in the presence of a Ziegler-Natta catalyst (Ziegler-Natta catalyst) as defined below. More preferably, the first propylene polymer (PP1) according to the invention is obtained by a process defined in detail below, by using a Ziegler-Natta catalyst.

The first propylene polymer (PP1) according to the present invention is preferably prepared in the presence of:

(a) a Ziegler-Natta catalyst (ZN-C1) comprising a compound of an IUPAC group 4 to 6 transition metal (TC), a group 2 Metal Compound (MC) and an Internal Donor (ID);

(b) optionally a promoter (Co), and

(c) an optional External Donor (ED).

Preferably, the first propylene polymer (PP1) is produced in a polymerization process comprising at least one reactor, e.g. two reactors (R1) and (R2), as described below. Preferably, the first propylene polymer (PP1) is produced in one polymerization reactor (R1).

The process for the preparation of the propylene homopolymer as well as the Ziegler-Natta catalyst is described in further detail below.

The polymerization reactor (R1) may be a Gas Phase Reactor (GPR) or a Slurry Reactor (SR). The Gas Phase Reactor (GPR) according to the invention is preferably a fluidized bed reactor, a fast fluidized bed reactor or a settled bed reactor or any combination thereof.

Preferably, the polymerization reactor (R1) is a Slurry Reactor (SR), which may be any continuous or simple stirred batch tank reactor or loop reactor operating in bulk or slurry form. Bulk refers to polymerization in a reaction medium comprising at least 60% (w/w) monomer. According to the present invention, the Slurry Reactor (SR) is preferably a (bulk) Loop Reactor (LR).

The second polymerisation reactor (R2) and any subsequent reactors, if present, are preferably Gas Phase Reactors (GPR). Such Gas Phase Reactor (GPR) may be any mechanically mixed reactor or a fluidized bed reactor. Preferably, the Gas Phase Reactor (GPR) comprises a fluidized bed reactor mechanically stirred at a gas velocity of at least 0.2 m/sec. Thus, it will be appreciated that the gas phase reactor is a fluidized bed type reactor preferably having a mechanical stirrer.

If any subsequent reactors are present, the propylene homopolymer of the first polymerization reactor (R1) is preferably fed directly to the second polymerization reactor (R2), i.e. directly to the (first) gas phase reactor (GPR1), without a flashing step between these stages. Such direct feeds are described in european patents EP 887379a, EP 887380a, EP 887381a and EP 991684A. By "direct feeding" is meant a process in which the content of the first polymerization reactor (R1), i.e. the Loop Reactor (LR), is directly passed to the gas phase reactor of the next stage.

Alternatively, the propylene homopolymer of the first polymerization reactor (R1), more preferably the polymer slurry of the Loop Reactor (LR), may also be directed to a flashing step or through an additional concentration step before being fed to the second polymerization reactor (R2), i.e. into the Gas Phase Reactor (GPR). Accordingly, the "indirect feeding" means that the content of the first polymerization reactor (R1), i.e. the content of the Loop Reactor (LR), i.e. the polymer slurry, is fed to the second polymerization reactor (R2), i.e. the (first) gas phase reactor (GPR1), via the reaction medium separation unit and as reaction medium for the gas from the separation unit.

However, it is preferred to prepare the propylene polymer (PP1) in one reactor, i.e. the polymerization reactor (R1) which is a Loop Reactor (LR).

If desired, a prepolymerization reactor is provided before the Slurry Reactor (SR), i.e.before the Loop Reactor (LR).

The Ziegler-Natta catalyst is fed into the polymerization reactor (R1). If the process further comprises a prepolymerization step, preferably all the Ziegler-Natta catalyst is fed to the prepolymerization reactor. The prepolymerised product comprising the Ziegler-Natta catalyst is then transferred into a polymerisation reactor (R1).

A preferred multi-stage process is a "loop-gas phase" process, such as the process developed by Borealis A/S of Denmark (referred to as the "loop-gas phase" process)

Techniques) described, for example, in the patent literature, for example in EP 0887379, WO 92/12182, WO 2004/000899, WO 2004/111095, WO 99/24478, WO 99/24479 or WO 00/68315.

Particularly good results can be obtained if the temperature in the reactor is carefully selected.

Therefore, it is preferable that the operating temperature in the polymerization reactor (R1) is in the range of 62 to 90 ℃, more preferably in the range of 65 to 85 ℃, still more preferably in the range of 67 to 83 ℃.

Generally, the pressure in the polymerization reactor (R1), preferably in the Loop Reactor (LR), is from 20 to 80bar, preferably from 30 to 70bar, such as from 35 to 65 bar.

For controlling the molecular weight, i.e. the melt flow rate MFR₂It is preferred to add hydrogen to each polymerization reactor.

Preferably, the average residence time in the polymerization reactor (R1) is relatively long. In general, the mean residence time (. tau.) is defined as the reaction volume (V)_R) And the volume outflow rate (Q) in the reactor_o) Ratio of (i.e. V)_R/Q_o) I.e. τ ═ V_R/Q_o[tau＝V_R/Q_o]. In the case of a loop reactor, the reaction volume (V)_R) Equal to the reactor volume.

Thus, the average residence time (. tau.) in the polymerization reactor (R1) is preferably at least 15min, more preferably in the range of 15 to 90min, still more preferably in the range of 20 to 80min, such as in the range of 24 to 60 min.

As mentioned above, the preparation of propylene homopolymer comprises, in addition to the (main) polymerization of propylene homopolymer in the polymerization reactor (R1), a prepolymerization in a Prepolymerization Reactor (PR) upstream of the polymerization reactor (R1).

Polypropylene (Pre-PP) is produced in the Prepolymerization Reactor (PR). The prepolymerization is carried out in the presence of a Ziegler-Natta catalyst. According to this embodiment, Ziegler-Natta, cocatalyst (Co) and External Donor (ED) are all introduced into the prepolymerization step. However, this should not exclude the option of adding further Co-catalyst (Co) and/or External Donor (ED) at a later stage, e.g. during the polymerization, e.g. in the first reactor (R1). In one embodiment, only the Ziegler-Natta catalyst, the cocatalyst (Co) and the External Donor (ED) are added to the Prepolymerization Reactor (PR), if a prepolymerization is carried out.

The prepolymerization is usually carried out at a temperature of from 0 to 60 ℃, preferably from 15 to 50 ℃, more preferably from 20 to 45 ℃.

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 70 bar.

In a preferred embodiment, the prepolymerization is carried out in liquid propylene in the form of a bulk slurry polymerization, i.e. the liquid phase comprises mainly propylene, optionally with inert components dissolved therein. Furthermore, according to the present invention, as mentioned above, ethylene feed is used in the prepolymerization process.

Other components may also be added in the prepolymerization stage. Thus, as known in the art, hydrogen may be added to the prepolymerization stage to control the molecular weight of the polypropylene (Pre-PP). In addition, antistatic additives may be used to prevent particles from adhering to each other or to the walls of the reactor.

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

Due to the above defined process conditions in the prepolymerization, it is preferred to obtain a Mixture (MI) of Ziegler-Natta catalyst and polypropylene (Pre-PP) produced in the Prepolymerization Reactor (PR). Preferably, the Ziegler-Natta catalyst is (finely) dispersed in the polypropylene (Pre-PP). In other words, the particles of Ziegler-Natta catalyst introduced into the Prepolymerization Reactor (PR) are broken into smaller fragments which are uniformly distributed in the growing polypropylene (Pre-PP). The size of the particles of the Ziegler-Natta catalyst introduced and the size of the fragments obtained are not critical for the invention and for the person skilled in the art.

As mentioned above, if a prepolymerization is used, the Mixture (MI) of Ziegler-Natta catalyst and polypropylene (Pre-PP) produced in the Prepolymerization Reactor (PR) is transferred to the first reactor (R1) after said prepolymerization. Generally, the total amount of polypropylene (Pre-PP) in the final propylene polymer (PP1) is very low and typically does not exceed 5.0 wt%, more preferably does not exceed 4.0 wt%, still more preferably is in the range of 0.5 to 4.0 wt%, e.g. is in the range of 1.0 to 3.0 wt%.

Propylene and other ingredients such as Ziegler-Natta catalysts are introduced directly into the first polymerization reactor (R1) without using prepolymerization.

Thus, the propylene homopolymer is preferably produced under the above conditions by a process comprising the steps of:

(a) in the first polymerization reactor (R1), i.e. in the Loop Reactor (LR), propylene is polymerized, yielding a first propylene polymer (PP 1).

The prepolymerization as described above may be carried out before step (a).

In the above process a Ziegler-Natta catalyst (ZN-C1) for the preparation of the first propylene polymer (PP1) was used. The Ziegler-Natta catalyst (ZN-C1) may be any stereospecific Ziegler-Natta catalyst (ZN-C1) for the polymerization of propylene, which is preferably capable of catalyzing the polymerization and copolymerization of propylene and optional comonomers at pressures of from 500 to 10000kPa, especially from 2500 to 8000kPa, and temperatures of from 40 to 110 ℃, especially from 60 to 110 ℃.

Preferably, the Ziegler-Natta catalyst (ZN-C1) comprises a high yield Ziegler-Natta type catalyst comprising an internal donor component, which can be used at high polymerization temperatures above 80 ℃. Such high yield Ziegler-Natta catalysts (ZN-C1) may comprise succinates, diethers, phthalates etc. or mixtures thereof as Internal Donors (ID) and are commercially available from LyondellBasell, for example under the trade name Avant ZN. Examples of Avant ZN series are Avant ZN 126 and Avant ZN 168. Avant zn 126 is a Ziegler-Natta catalyst with 3.5 wt% titanium and diether compounds as internal electron donors, commercially available from LyondellBasell. Avant ZN168 is a Ziegler-Natta catalyst with 2.6 wt% titanium and succinate compounds as internal electron donors, commercially available from lyondellbasell. Another example of Avant ZN series is LyondellBasell catalyst ZN 180M.

Further suitable catalysts are described, for example, in WO 2012/007430, EP2610271, EP261027 and EP 2610272.

The Ziegler-Natta catalyst (ZN-C1) is preferably used in combination with an alkylaluminum cocatalyst and optionally an external donor.

As further component in the polymerization process of the invention, preferably an External Donor (ED) is present. Suitable External Donors (ED) include certain silanes, ethers, esters, amines, ketones, heterocyclic compounds and blends of these. The use of silanes is particularly preferred. Most preferably, silanes of the general formula:

R^a _pR^b _qSi(OR^c)_(4-p-q)，

wherein R is^a，R^bAnd R^cRepresents a hydrocarbon group, in particular an alkyl or cycloalkyl group,

wherein p and q are numbers from 0 to 3, and their sum p + q is equal to or less than 3. R^a，R^bAnd R^cMay be selected independently of each other and may be the same or different. A specific example of such a silane is (tert-butyl)₂Si(OCH₃)₂(cyclohexyl) (methyl) Si (OCH)₃)₂(phenyl group)₂Si(OCH₃)₂And (cyclopentyl)₂Si(OCH₃)₂Or a silane of the formula:

Si(OCH₂CH₃)₃(NR³R⁴)，

wherein R is³And R⁴May be the same or different and represents a hydrocarbon group having 1 to 12 carbon atoms.

R³And R⁴Independently selected from the group consisting of a straight aliphatic hydrocarbon group having 1 to 12 carbon atoms, a branched aliphatic hydrocarbon group having 1 to 12 carbon atoms and a cyclic aliphatic hydrocarbon group having 1 to 12 carbon atoms. Particularly preferably, R³And R⁴Independently selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decyl, isopropyl, isobutyl, isopentyl, tert-butyl, tert-pentyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

More preferably R³And R⁴Likewise, R is still more preferred³And R⁴Are all ethyl groups.

It is particularly preferred that the External Donor (ED) is a dicyclopentyldimethoxysilane donor (D-donor) or a cyclohexylmethyldimethoxysilane donor (C-donor).

In addition to the Ziegler-Natta catalyst (ZN-C1) and optional External Donor (ED), a cocatalyst may be used. The cocatalyst is preferably a compound of group 13 of the periodic Table (IUPAC), for example an organoaluminium, such as an aluminium compound, for example an aluminium alkyl, aluminium halide or aluminium alkyl halide compound. Thus, in a particular embodiment, the cocatalyst (Co) is a trialkylaluminum, such as Triethylaluminum (TEAL), dialkylaluminum chloride or alkylaluminum dichloride or a mixture thereof. In a particular embodiment, the cocatalyst (Co) is Triethylaluminium (TEAL).

Preferably, the ratio between the cocatalyst (Co) and the External Donor (ED) [ Co/ED ] and/or the ratio between the cocatalyst (Co) and the Transition Metal (TM) [ Co/TM ] should be carefully chosen.

Therefore, the temperature of the molten metal is controlled,

(a) the molar ratio of cocatalyst (Co) to External Donor (ED) [ Co/ED ] must be in the range of 5 to 45, preferably in the range of 5 to 35, more preferably in the range of 5 to 25;

and optionally

(b) The molar ratio [ Co/TC ] of the cocatalyst (Co) to the Titanium Compound (TC) must be in the range of higher than 80 to 500, preferably in the range of 90 to 350, and still more preferably in the range of 100 to 300.

In another embodiment, the Ziegler-Natta catalyst (ZN-C1) may be modified by polymerizing a vinyl compound in the presence of a catalyst system comprising a special Ziegler-Natta procatalyst (component (i)), an external donor (component (iii)) and optionally a cocatalyst (component (iii)), the vinyl compound having the formula:

CH₂＝CH-CHR⁵R⁶

wherein R is⁵And R⁶Together 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 first propylene polymer (PP1) according to the present invention. The polymerized vinyl compound can be used as an alpha-nucleating agent.

With regard to the modification of the catalyst, reference is made to international applications WO 99/24478, WO 99/24479, in particular WO 00/68315, the contents of which are incorporated herein by reference with regard to the reaction conditions associated with the modification of the catalyst and with regard to the polymerization reaction.

Second propylene Polymer (PP2)

The second propylene polymer (PP2) preferably has a moderate melt flow rate. Thus, it is preferred that the second propylene polymer (PP2) has a melt flow rate MFR determined according to ISO 1133 at 230 ℃ and under a load of 2.16kg₂In the range of 20.0 to 150.0g/10min, more preferably in the range of 30.0 to 120.0g/10min, still more preferably in the range of 40.0 to 90.0g/10min, such as in the range of 50.0 to 65.0g/10 min.

Preferably the second propylene polymer (PP2) is characterized by a rather low Xylene Cold Soluble (XCS) content, i.e. less than 4.1 wt% Xylene Cold Soluble (XCS). Accordingly, the Xylene Cold Soluble (XCS) content of the second propylene polymer (PP2) is preferably in the range of 1.0 to 4.0 wt.%, more preferably in the range of 1.0 to 3.0 wt.%, still more preferably in the range of 1.5 to 2.5 wt.%.

Thus, similar to the first propylene polymer (PP1), preferably the second propylene polymer (PP2) does not contain any elastomeric component. In this respect, reference is made to the definitions provided above.

In addition, the second propylene polymer (PP2) is preferably a crystalline propylene homopolymer. With respect to the term "crystalline", reference is made to the definitions provided above. Thus, the second propylene polymer (PP2) preferably has a melting temperature Tm, as measured by Differential Scanning Calorimetry (DSC), of at least 145 ℃, more preferably at least 150 ℃, still more preferably at least 155 ℃, such as in the range of 150 ℃ to 160 ℃.

Further, it is preferable that the second propylene polymer (PP2) has a crystallization temperature Tc as measured by Differential Scanning Calorimetry (DSC) equal to or greater than 108 ℃, more preferably in the range of 110 to 130 ℃, more preferably in the temperature range of 115 to 125 ℃.

Preferably, the second propylene polymer (PP2) is obtained by polymerizing propylene in the presence of a Ziegler-Natta catalyst. More preferably, the second propylene polymer (PP2) according to the present invention is obtained by a process using a Ziegler-Natta catalyst.

For the preparation of the second propylene polymer (PP2), the polymerization process and Ziegler-Natta catalyst described above for the first propylene polymer (PP1) can be used. Therefore, reference is made to the above process and Ziegler-Natta catalyst for the first propylene polymer (PP 1).

Fiber (F)

An essential component of the fiber-reinforced polypropylene composition (C) of the present invention is the fiber (F).

Preferably, the fibers (F) are Short Fibers (SF).

Preferably, the Short Fibers (SF) are selected from glass fibers, metal fibers, mineral fibers, ceramic fibers, carbon fibers and graphite fibers. Glass fibers are particularly preferred. Therefore, the Short Fiber (SF) is preferably a Short Glass Fiber (SGF). In particular, Short Glass Fibers (SGF) are cut glass fibers, also known as staple fibers or chopped strands.

Similar to the glass staple fibers (SGF) used in the fiber reinforced polypropylene composition (C), the average length of the cut fibers or Staple Fibers (SF) is preferably in the range of 1.0 to 10.0mm, more preferably in the range of 2.0 to 8.0mm, still more preferably in the range of 3.0 to 5.0mm, for example in the range of 3.0 to 4.5 mm.

Similar to the Short Glass Fibers (SGF) used in the fiber reinforced polypropylene composition (C), the average diameter of the cut fibers or Short Fibers (SF) is preferably from 8 to 20 μm, more preferably from 9 to 16 μm, still more preferably from 9 to 14 μm, for example from 9 to 13 μm.

Preferably, the Short Fibers (SF), such as Short Glass Fibers (SGF), have an aspect ratio of 125 to 650, preferably 200 to 600, more preferably 300 to 600, still more preferably 400 to 550. The aspect ratio is the relationship between the average length and the average diameter of the fibers.

Adhesion Promoter (AP)

According to the present invention, the fiber reinforced polypropylene composition (C) further comprises an Adhesion Promoter (AP). The Adhesion Promoter (AP) is designated as a polar modified polypropylene (PM-PP) homopolymer or copolymer.

The polar modified polypropylene (PM-PP) homopolymer or copolymer comprises a low molecular weight compound having a reactive polar group. Modified polypropylene homopolymers and copolymers, e.g. copolymers of propylene and ethylene or propylene with other alpha-olefins such as C₄To C₁₀Copolymers of alpha-olefins are most preferred because they are highly compatible with the Propylene Polymer (PP) of the fiber reinforced polypropylene composition (C) of the present invention.

In terms of structure, the polar modified polypropylene (PM-PP) homopolymer or copolymer is preferably selected from grafted homopolymers or copolymers.

Preference is given here to polar modified polypropylene (PM-PP) homopolymers or copolymers which contain groups derived from polar compounds, in particular from the group of anhydrides, carboxylic acids, carboxylic acid derivatives, primary and secondary amines, hydroxyl compounds, oxazolines and epoxides and also ionic compounds.

Specific examples of the polar compound are unsaturated cyclic anhydrides and aliphatic diesters thereof, and diacid derivatives. In particular, maleic anhydride and a compound selected from C may be used₁To C₁₀Linear and branched dialkyl maleates, C₁To C₁₀Linear and branched dialkyl fumarates, itaconic anhydride, C₁To C₁₀Linear and branched dialkyl itaconates of (a), acrylic acid, maleic acid, fumaric acid, itaconic acid and mixtures thereof.

It is particularly preferred to use polypropylene homo-or copolymers grafted with maleic anhydride or acrylic acid as polar modified polypropylene (PM-PP) homo-or copolymer, i.e. Adhesion Promoter (AP).

The modifying polymers, i.e. adhesion promoters, are commercially available or are produced in a simple manner by extruding the polymers in the presence of free radical generators, such as organic peroxides, for example by reaction with maleic anhydride or acrylic acid, as disclosed in US 4,506,056, US 4,753,997 or EP 1805238.

In the fiber reinforced polypropylene composition (C) of the present invention, the preferred amount of the polar modified polypropylene (PM-PP) homopolymer or copolymer, i.e. the Adhesion Promoter (AP), is 1 to 10 wt%. For example, in the range of 2.0 wt% to 8 wt%, preferably in the range of 3.0 wt% to 6 wt%, most preferably in the range of 3.0 wt% to 6.0 wt%.

The preferred amount of groups derived from polar compounds in the polar modified polypropylene (PM-PP) homo-or copolymer, i.e. Adhesion Promoter (AP), is 0.5 to 10 wt%. For example, in the range of 0.5 wt% to 8 wt%, preferably in the range of 0.5 wt% to 6 wt%, more preferably in the range of 0.5 wt% to 4 wt%, most preferably in the range of 0.5 wt% to 3.5 wt%.

Melt flow Rate MFR of a polar modified Polypropylene (PM-PP) homopolymer or copolymer, i.e. Adhesion Promoter (AP)₂A preferred value of (190 ℃) is 30 to 200g/10 min. Particular preference is given to the melt flow rate MFR of polar modified polypropylene (PM-PP) homo-or copolymers₂(190 ℃) of at least 80g/10 min.

In a preferred embodiment of the present invention, the Adhesion Promoter (AP) is a maleic anhydride modified polypropylene homo-or copolymer and/or an acrylic modified polypropylene homo-or copolymer. Preferably, the Adhesion Promoter (AP) is a maleic anhydride modified polypropylene homopolymer and/or an acrylic acid modified polypropylene homopolymer, preferably a maleic anhydride modified polypropylene homopolymer. For example, suitable polar modified polypropylene (PM-PP) homopolymers or copolymers include, for example, maleic anhydride grafted polypropylene homopolymers (PP-g-MAH) and acrylic acid grafted polypropylene homopolymers (PP-g-AA).

Additive (AD)

The fiber reinforced polypropylene composition (C) of the present invention may comprise Additives (AD) in addition to the Propylene Polymer (PP), the Adhesion Promoter (AP) and the fibers (F). Typical additives are acid scavengers, antioxidants, colorants, light stabilizers, plasticizers, slip agents, scratch resistance agents, dispersants, processing aids, lubricants, pigments, and the like.

Such Additives are commercially available and are described, for example, in the "plastics Additives Handbook" (pages 1141 to 1190) of the sixth 2009 of Hans Zweifel.

Furthermore, the term "Additive (AD)" according to the invention also includes carrier materials, in particular polymeric carrier materials.

Polymeric carrier material

Preferably, the fiber reinforced polypropylene composition (C) of the present invention does not comprise (a) other polymers than the Propylene Polymer (PP) and the Adhesion Promoter (AP) in an amount of more than 15 wt%, preferably not more than 10 wt%, more preferably not more than 5 wt%, based on the weight of the fiber reinforced polypropylene composition (C). Any polymer as support material for the Additive (AD) is not calculated as the amount of the polymer compound according to the invention, but as the amount of the respective additive.

The polymeric carrier material of the Additive (AD) is a carrier polymer to ensure a homogeneous distribution in the fiber reinforced polypropylene composition (C) of the invention. The polymeric carrier material is not limited to a particular polymer. The polymeric carrier material may be an ethylene homopolymer, derived from ethylene and an alpha-olefin comonomer such as C₃To C₈Ethylene copolymers derived from alpha-olefin comonomers, propylene homopolymers and/or copolymers derived from propylene and alpha-olefin comonomers, e.g. ethylene and/or C₄To C₈Propylene copolymers from alpha-olefin comonomers, most preferably propylene homopolymers. Preferably, the polymeric support material does not comprise monomer units derived from styrene or derivatives thereof.

Article of manufacture

The present invention also provides an injection moulded article, such as an injection moulded automotive article, comprising the fiber reinforced polypropylene composition (C) as defined above. The invention especially provides an injection molded article, such as an injection molded automotive article, comprising at least 60 wt%, more preferably at least 80 wt%, still more preferably at least 90 wt%, such as at least 95 wt% or at least 99 wt% of the fiber reinforced polypropylene composition (C) as defined above. In a particularly preferred embodiment, the present invention provides an injection molded article, such as an injection molded automotive article, consisting of the fiber reinforced polypropylene composition (C) as defined above.

Particularly preferably, the injection molded automotive article is an automotive engine article, such as an intake manifold of an engine.

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

Examples

1. Measuring method

MFR₂(230 ℃) in accordance with ISO 1133 at 230 ℃ and a load of 2.16 kg.

Melt flow Rate MFR of the Propylene Polymer (PP)₂(230 ℃) calculated according to formula (IX):

logMFR(PP)＝w(PP1)×logMFR(PP1)+w(PP2)×logMFR(PP2) (IX)

wherein the content of the first and second substances,

w (PP1) is the weight fraction of the first propylene polymer (PP1),

w (PP2) is the weight fraction of the second propylene polymer (PP2),

MFR (PP1) is the melt flow Rate MFR of the first propylene Polymer (PP1)₂(230 ℃, 2.16kg load), in g/10min,

MFR (PP2) is the melt flow Rate MFR of the second propylene polymer (PP2)₂(230 ℃, 2.16kg load), in g/10min,

MFR (PP) is the melt flow Rate MFR of the Propylene Polymer (PP)₂(230 ℃, 2.16kg load), in g/10min,

the same applies to the two fractions PP1a and PP1b of the bimodal polymer PP1 and bimodal PP 1.

Quantification of microstructure by NMR spectroscopy

Quantitative Nuclear Magnetic Resonance (NMR) spectroscopy was used to quantify the comonomer content and comonomer sequence distribution of the polymer. To is directed at¹H and¹³c, recording the state of the solution at 400.15MHz and 100.62MHz respectively using a Bruker Advance III 400NMR spectrometer¹³C{¹H } NMR quantitative spectrum. Use of¹³C optimal 10mm extended temperature probe, all spectra were recorded at 125℃ for all atmospheres using nitrogen. About 200mg of the material was mixed with chromium (III) acetylacetonate (Cr (acac)₃) Dissolved together in 3ml of 1, 2-tetrachloroethane-d₂(TCE-d₂) To obtain a 65mM relaxant solution in solvent (Singh, g., Kothari, a., Gupta, v., Polymer Testing 285 (2009), 475). To ensure the solution is homogeneous, after initial sample preparation in the hot zone, the NMR tube is further heated in a rotary oven for at least 1 hour. After the magnet was inserted, the tube was rotated at 10 Hz. This setup was chosen primarily to achieve high resolution and quantitative requirements for accurate quantification of ethylene content. Using standard single pulse excitation without NOE, an optimal tip angle, 1s cycle delay and a two-stage WALTZ16 decoupling scheme (Zhou, z., Kuemmerle, r., Qiu, x., Redwine, d., Cong r., Taha, a., Baugh, d.winnoford, b., j.mag.reson.187(2007) 225; Busico, v., Carbonniere, p., Cipullo, r., pellechia, r., seven, j., talaro, g., macromol.rapid com.2007, 28, 1128) were employed. A total of 6144(6k) transients were collected for each spectrum.

Using a proprietary computer program pair¹³C{¹H NMR quantitative spectra were processed, integrated and the relevant quantitative properties were determined from the integration. Chemical shifts of the solvent were used, all chemical shifts being indirectly referenced to the central methylene of the ethylene block (EEE) at 30.00 ppm. This method can be referred to analogously even without this structural element. A characteristic signal corresponding to ethylene incorporation was observed (Cheng, h.n., Macromolecules 17(1984), 1950).

For polypropylene homopolymer, all chemical shifts are internally referenced to methyl isotactic pentads (mmmm) at 21.85 ppm.

Characteristic signals corresponding to regio-defects (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., chem.Rev.2000,100, 1253; Wang, W-J., Zhu, S., Macromolecules 33(2000), 1157; Cheng, H.N., Macromolecules 17(1984),1950) or comonomers are observed.

The isotacticity distribution (tactility) was quantified by integrating the methyl region between 23.6-19.7ppm by correcting for any sites not related to the target stereosequence (Busico, V., Cipullo, R., Prog. Polym.Sci.26(2001) 443; Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromoleucles 30(1997) 6251).

Specifically, the effect of regio-defects and comonomer on the quantification of isotacticity distribution was corrected by subtracting the representative regio-defects and comonomer integrals from the specific integrated regions of the stereoseries.

Isotacticity is determined at the pentad level and is reported as the percentage of isotactic pentad (mmmm) sequences relative to all pentad sequences:

[ mmmm ]% ═ 100X (mmmm/sum of all pentads)

The presence of 2,1 erythro defects was indicated by the presence of two methyl sites at 17.7ppm and 17.2ppm and confirmed by other characteristic sites.

No signature corresponding to other types of area defects was observed (Resconi, l., cavalo, l., fat, a., pimetonesis, f., chem. rev.2000,100, 1253).

The average integral of the two characteristic methyl sites at 17.7ppm and 17.2ppm was used to quantify the amount of 2,1 erythro regio defects:

P_21e＝(I_e6+I_e8)/2，

the amount of 1,2 major insertions of propylene was quantified in terms of the methyl region and corrected for sites included in the region not associated with the major insertion and sites not included in the region:

P₁₂＝I_CH3+P_12e

the total amount of propylene was quantified as the sum of the main inserted propylene and all other existing regio defects:

P_{general assembly}＝P₁₂+P_21e

The molar percentage of defects of the 2,1 erythro region was quantified with respect to all propylene:

[21e]mol％＝100×(P_21e/P_{general assembly})

For the copolymers, a characteristic signal corresponding to the incorporation of ethylene was observed (Cheng, h.n., Macromolecules 17(1984), 1950).

Regio defects (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., chem.Rev.2000,100, 1253; Wang, WJ., Zhu, S., Macromolecules 33(2000), 1157; Cheng, HN, Macromolecules 17(1984),1950) were also observed, and the effect of such defects on comonomer content needs to be corrected.

Using the method of Wang et al, by penetration¹³C{¹H integration of multiple signals across the entire spectral region in the spectrum, the comonomer fraction was quantified (Wang, W-j., Zhu, s., Macromolecules 33(2000), 1157). This method was chosen because of its stability (robust nature) and its ability to compute, if necessary, the presence of regional defects. The integration region is fine tuned to increase the applicability to the comonomer content encountered over the entire range.

For systems where only isolated ethylene in the PPEPP sequence is observed, the method of Wang et al is modified to reduce the effect of non-zero integration of sites known to be absent. The method reduces the overestimation of ethylene content in such systems and is achieved by reducing the number of sites used to determine absolute ethylene content:

E＝0.5(Sββ+Sβγ+Sβδ+0.5(Sαβ+Sαγ))

by using this set of stations, the corresponding integral equation becomes:

E＝0.5(I_H+I_G+0.5(I_C+I_D))

the same notation is used as in Wang et al. (Wang, W-J., Zhu, S., Macromolecules 33(2000), 1157). The equation for absolute propylene content is not modified.

The mole percentage of comonomer incorporated is calculated from the mole fraction:

E[mol％]＝100×fE

the weight percentage of incorporated comonomer was calculated from the weight fraction:

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

comonomer sequence distribution at the level of the triad was determined using the analytical method of Kakugo et al. (Kakugo, m., Naito, y., mizunma, k., Miyatake, t.macromolecules 15(1982) 1150). This method was chosen for its stability (robust nature) and the integration region was fine tuned to improve its applicability in a wider range of comonomer contents.

DSC analysis, melting temperature (T)_m) And heat of fusion (H)_f) Crystallization temperature (T)_c) And enthalpy of fusion (H)_m): measurements were made on 5 to 7mg samples using a TA instruments Q200 Differential Scanning Calorimeter (DSC). The DSC was run at a temperature of-30 to +225 ℃ in a heating/cooling/heating cycle with a scan rate of 10 ℃/min according to ISO 11357/part 3/method C2. Determination of the crystallization temperature (T) from the Cooling step_c) And the melting temperature (T) is determined by the second heating step_m) And enthalpy of fusion (H)_m). By assuming H of fully crystalline polypropylene_mThe value was 209J/g, and the crystallinity was calculated from the enthalpy of fusion (see Brandrup, J., Immergut, E.H., eds. Polymer Handbook, third edition, Willi, New York, 1989; Chapter 3).

Xylene solubles (XCS, wt%): the content of Xylene Cold Soluble (XCS) is determined according to ISO 16152 at 25 ℃; a first edition; 2005-07-01. The fraction remaining insoluble is the Xylene Cold Insoluble (XCI) fraction.

The ash content is measured according to ISO 3451-1 (1997).

Charpy (Charpy) notched impact strength and Charpy unnotched impact strength: determined according to ISO179-1/1 eA and ISO179-1/1eU at 23 ℃ using injection-molded specimens (80X 10X 4mm) as described in ISO 19069-2.

Tensile properties were determined on injection-molded dog bone specimens (170X 10X 4mm) prepared according to ISO 527-1A. Tensile modulus was determined according to ISO 527-1A at 1mm/min and 23 ℃. To determine the yield stress and yield strain, a speed of 50mm/min was used.

Oil resistance was measured as follows: the tensile specimens were immersed in an engine oil "ow-20" from Mobil for 250h, 500h and 1000h, respectively, at room temperature, and then the Tensile Strength (TS) and Tensile Modulus (TM) were determined. The retention rate was determined as follows:

elongation at break: compression moulded samples of 4mm thickness prepared according to EN ISO 1873-2 were used, determined according to ISO 527/2/5A at 50mm/min and 23 ℃.

Flexural modulus: according to ISO 178, the use of a mixture according to ISO 294-1: 1996, and flexural modulus was determined by three-point bending on an 80X 10X 4mm injection molded sample.

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

2. Detailed description of the invention

The following inventive example IE was prepared by mixing on a co-rotating twin screw extruder. In particular, the Propylene Polymer (PP), i.e. the first propylene polymer (PP1) and the optional second propylene polymer (PP2), is premixed with the Additive (AD) and the Adhesion Promoter (AP). The base resin thus obtained was fed into the main feeder of the extruder, and Short Fibers (SF) were added through the side feeder. The material is extruded at a temperature of 210 to 230 ℃. Table 1 summarizes the compositions and properties thereof.

Table 1: compositions and Properties of examples and comparative examples

CE is a commercially available fiber reinforced propylene copolymer compound comprising 53 wt% propylene homopolymer, 8.0 wt% propylene/ethylene copolymer rubber, 36 wt% glass fiber and 1.5 wt% adhesion promoter (which is polypropylene functionalized with maleic anhydride).

PP1 is a propylene homopolymer having a melt flow rate MFR₂(230 ℃, 2.16kg) was 8.0g/10min, the xylene solubles content XCS was 1.0 wt%.

PP2 is a propylene homopolymer having a melt flow rate MFR₂(230 ℃) 60g/10min, a xylene solubles content XCS of 2.0 wt% and comprises 0.8 wt% of ethylene comonomer units.

SF is a commercial product 249A from Owens Corning (USA) with a diameter of 10.0 μm and a wire length (strand length) of 4.5 mm.

AP is

An adhesion promoter SCONA TPPP 8112GA from BYK-Chemie GmbH (Germany) is a polypropylene functionalized with maleic anhydride with a maleic anhydride content of 1.4 wt.% and an MFR (190 ℃ C.) of more than 80g/10 min.

AD is a composition comprising 24 parts by weight of a polymeric carrier material which is a propylene homopolymer, 24 parts by weight of the antioxidant DSTDP from BASF, 8 parts by weight of the antioxidant Irgafos 168 from BASF, 16 parts by weight of the antioxidant Irganox1010 from BASF, 8 parts by weight of the antioxidant Richnox XL-1 from Rich Yu Chemical co, taiwan and 20 parts by weight of carbon black.

As can be seen from table 1, the retention of tensile modulus and tensile strength of the fiber reinforced polypropylene composition of the present invention is higher than the corresponding values of the comparative composition comprising a polypropylene compound and a rubber.

Claims (16)

1. Fiber reinforced polypropylene composition (C) comprising:

i) propylene Polymers (PP) having a xylene solubles content XCS equal to or lower than 5.0 wt. -%,

ii) fibers (F), and

iii) an Adhesion Promoter (AP),

wherein the fiber reinforced polypropylene composition satisfies the inequality (I):

wherein w (PP) is the weight fraction of the Propylene Polymer (PP) in wt% of the total weight of the fiber reinforced polypropylene composition (C) and w (AP) is the weight fraction of the Adhesion Promoter (AP) in wt% of the total weight of the fiber reinforced polypropylene composition (C).

2. The fiber reinforced polypropylene composition (C) according to claim 1, wherein the Propylene Polymer (PP) is monophasic.

3. The fiber reinforced polypropylene composition (C) according to claim 1 or 2, wherein the fiber reinforced polypropylene composition (C) does not comprise a propylene polymer having a xylene solubles content XCS higher than 5.0 wt%.

4. The fiber reinforced polypropylene composition (C) according to any one of the preceding claims, wherein the fiber reinforced polypropylene composition (C) satisfies the inequality (II):

wherein w (F) is the weight fraction of fibers (F) in wt% of the total weight of the fiber reinforced polypropylene composition (C) and w (AP) is the weight fraction of Adhesion Promoter (AP) in wt% of the total weight of the fiber reinforced polypropylene composition (C).

5. Fiber reinforced polypropylene composition (C) according to any one of the preceding claims, wherein the Propylene Polymer (PP) is bimodal.

6. The fiber reinforced polypropylene composition (C) according to any one of the preceding claims, wherein the Propylene Polymer (PP) is a propylene homopolymer (H-PP).

7. The fiber reinforced polypropylene composition (C) according to any one of the preceding claims, wherein the Propylene Polymer (PP) comprises:

i) a first propylene polymer (PP1) having a melt flow rate MFR determined according to ISO 1133₂(230 ℃, 2.16kg) equal to or lower than 20g/10min, and

ii) a second propylene polymer (PP2) having a melt flow rate MFR determined according to ISO 1133₂(230 ℃, 2.16kg) is more than 20g/10 min.

8. Fiber reinforced polypropylene composition (C) according to any one of the preceding claims, wherein the fibers (F) are Staple Fibers (SF).

9. Fiber reinforced polypropylene composition (C) according to any one of the preceding claims, wherein the fibers (F) are Glass Fibers (GF), preferably Short Glass Fibers (SGF).

10. Fiber reinforced polypropylene composition (C) according to claim 8 or 9, wherein the Short Fibers (SF), preferably the Short Glass Fibers (SGF), have:

i) an average length of 1.0 to 10.0mm, and/or

ii) an average diameter of 8 to 20 μm.

11. Fiber reinforced polypropylene composition (C) according to any one of the preceding claims, wherein the Adhesion Promoter (AP) is a polar modified polypropylene (PM-PP) being a maleic anhydride grafted propylene homo-or copolymer having a melt flow rate MFR (190 ℃, 2.16kg) determined according to ISO 1133 of at least 80.0g/10 min.

12. The fiber reinforced polypropylene composition (C) according to any one of the preceding claims, wherein the fiber reinforced polypropylene composition (C) comprises, based on the total weight of the fiber reinforced polypropylene composition (C):

i) from 50.0 to 80.0% by weight of a Propylene Polymer (PP) having a xylene solubles content XCS equal to or lower than 5.0% by weight,

ii)15.0 to 40.0 wt% of fibres (F),

iii)3.0 to 10.0 wt.% of an Adhesion Promoter (AP), and

iv) optionally 0.1 to 4.0 wt.% of Additives (AD).

13. Article comprising the fiber reinforced polypropylene composition (C) according to any one of claims 1 to 12.

14. The article according to claim 13, comprising at least 90 wt% of the fiber reinforced polypropylene composition (C).

15. The article of claim 13 or 14, wherein the article is an automotive article, preferably an automotive engine article.

16. The article of any one of claims 13-15, wherein the article is an intake manifold of an automotive engine.