阅读说明：本技术 可发泡聚丙烯组合物 (Foamable polypropylene composition ) 是由 丹妮拉·米列瓦 苏珊娜·卡伦 帕特里克·罗孚 格奥尔格·格雷斯滕伯格 王静波 克劳斯·贝恩 于 2019-10-02 设计创作，主要内容包括：本发明涉及一种聚丙烯组合物、包括聚丙烯组合物的注射成型制品、包括聚丙烯组合物的发泡制品以及聚丙烯均聚物(H-PP1)用于降低发泡的注射成型制品的刚度折减系数的用途,刚度折减系数是通过未发泡与发泡的注射成型制品的根据ISO 178测量的弯曲模量的差确定的,且与包括在齐格勒-纳塔催化剂的存在下聚合的相同量的聚丙烯的制品相比,发泡的注射成型制品的刚度折减系数被降低了至少40。(The present invention relates to a polypropylene composition, an injection moulded article comprising the polypropylene composition, a foamed article comprising the polypropylene composition and the use of polypropylene homopolymer (H-PP1) for reducing the stiffness reduction factor of a foamed injection moulded article, the stiffness reduction factor being determined by the difference in flexural modulus measured according to ISO 178 of an unfoamed and a foamed injection moulded article, and the stiffness reduction factor of the foamed injection moulded article being reduced by at least 40 compared to an article comprising the same amount of polypropylene polymerised in the presence of a ziegler-natta catalyst.)

1. A polypropylene composition comprising

a) 45 to 97.5 wt%, based on the total weight of the composition, of a polypropylene homopolymer (H-PP1) having (H-PP1)

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 150 to 160 ℃,

ii) in the range of 0.50 to 1.00 mol% of a monomer mixture of¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy,

iii) at least 97.5% of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and

iv) a xylene cold soluble fraction (XCS) determined according ISO 16152 at 23 ℃ equal to or lower than 1.5 wt. -%,

b) from 0 to 55 wt. -%, based on the total weight of the composition, of polypropylene (PP2),

c) 0 to 30% by weight, based on the total weight of the composition, of a filler (F), and

d) 2.5 to 5 wt. -%, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, foaming agents, antioxidants and mixtures thereof,

wherein the sum of the amounts of the polypropylene homopolymer (H-PP1), the polypropylene (PP2), the filler (F) and the at least one additive in the polypropylene composition is 100.0 wt.%.

2. The polypropylene composition according to claim 1, wherein the composition comprises, preferably consists of,

a) 95 to 97.5 wt%, based on the total weight of the composition, of the polypropylene homopolymer (H-PP1), and

b) 2.5 to 5 weight percent, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, and mixtures thereof.

3. The polypropylene composition according to claim 1, wherein the composition comprises, preferably consists of,

a) 45 to 52.5 wt. -%, based on the total weight of the composition, of the polypropylene homopolymer (H-PP1),

b) 45 to 55 wt%, based on the total weight of the composition, of polypropylene (PP2), and

c) 2.5 to 5 weight percent, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, and mixtures thereof.

4. The polypropylene composition according to any one of claims 1 to 3, wherein the composition has

a) Melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 80.0g/10min₂(230 ℃ C.); and/or

b) A content of volatile organic compounds of not more than 170 [ mu ] g/g of the composition in the unfoamed injection molded part; and/or

c) A content of volatile organic compounds of not more than 200 μ g/g of the composition in particulate form; and/or

d) A glass transition temperature Tg (measured with DMTA according to ISO 6721-7) of 0 ℃ or higher, preferably +1 ℃ or higher.

5. The polypropylene composition according to any one of claims 1 to 4, wherein the composition comprises 0.1 to 0.5 wt. -%, based on the total weight of the composition, of a nucleating agent, preferably a nucleating agent comprising 1, 2-cyclohexanedicarboxylic acid.

6. The polypropylene composition according to any one of claims 1 to 5, wherein the polypropylene (PP2) is a polypropylene homopolymer (H-PP 2).

7. The polypropylene composition according to any one of claims 1 to 6, wherein the polypropylene homopolymer (H-PP1) and/or the polypropylene (PP2) has a melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 100.0g/10min, preferably in the range of 25.0 to 90.0g/10min₂(230℃)。

8. The polypropylene composition according to any one of claims 1 to 7, wherein the polypropylene homopolymer (H-PP1) has a melt flow rate MFR measured according to ISO 1133₂(230 ℃) with the melt flow rate MFR, measured according to ISO 1133, of the said polypropylene (PP2)₂The difference (230 ℃) is less than 20.0g/10min, preferably less than 15.0g/10min and most preferably less than 10.0 g/min.

9. The polypropylene composition according to any one of claims 1 to 8, wherein the polypropylene homopolymer (H-PP1)

i) Is unimodal, and/or

ii) has a molecular weight distribution Mw/Mn, measured according to ISO16014, in the range ≦ 4.0, preferably in the range from 2.0 to 4.0 and most preferably in the range from 2.5 to 4.0.

10. The polypropylene composition according to any one of claims 1 to 9, wherein the polypropylene homopolymer (H-PP1) has

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 150 to 160 ℃,

ii) in the range of 0.50 to 1.00 mol% of a monomer mixture of¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy,

iii) at least 97.5% of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and

iv) a xylene cold soluble fraction (XCS) determined according ISO 16152 at 23 ℃ equal to or lower than 1.5 wt. -%.

11. The polypropylene composition according to any one of claims 1 to 10, wherein the polypropylene (PP2) has

i) A melting temperature Tm in the range of 162 to 170 ℃ as measured by Differential Scanning Calorimetry (DSC), and/or

ii) less than or equal to 0.10 mol% of¹³The content of 2,1 erythro-type domain defects determined by C-NMR spectroscopy, and/or

iii) in the range of 95.0 to 98.0% of a compound of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and/or

iv) a molecular weight distribution Mw/Mn, measured according to ISO16014, in the range ≥ 4.0, and/or

iv) a xylene cold soluble fraction (XCS) determined according to ISO 16152 at 23 ℃ in the range of 1.5 to 3.5 wt.%.

12. The polypropylene composition according to any one of claims 1 to 11, wherein the composition has a bimodal molecular structure.

13. The polypropylene composition according to any one of claims 1 to 11, wherein the filler (F) is selected from the group consisting of talc, mica, wollastonite, glass fibers, carbon fibers and mixtures thereof.

14. An injection molded article comprising the polypropylene composition according to any one of claims 1 to 13.

15. A foamed article, preferably a foamed injection molded article, comprising the polypropylene composition of any one of claims 1 to 13.

16. Use of a polypropylene homopolymer (H-PP1) for reducing the stiffness reduction factor of a foamed injection molded article, the stiffness reduction factor being determined by the difference in flexural modulus measured according to ISO 178 of unfoamed and foamed injection molded article and the stiffness reduction factor of the foamed injection molded article being reduced by at least 40 compared to an article comprising the same amount of polypropylene polymerized in the presence of a ziegler-natta catalyst, wherein the polypropylene homopolymer (H-PP1) has

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 150 to 160 ℃,

ii) in the range of 0.50 to 1.00 mol% of a monomer mixture of¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy,

iii) at least 97.5% of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and

iv) a xylene cold soluble fraction (XCS) determined according ISO 16152 at 23 ℃ equal to or lower than 1.5 wt. -%.

Technical Field

The present invention relates to a polypropylene composition, an injection moulded article comprising the polypropylene composition, a foamed article comprising the polypropylene composition and the use of polypropylene homopolymer (H-PP1) for reducing the stiffness reduction factor of a foamed injection moulded article, the stiffness reduction factor being determined by the difference in flexural modulus measured according to ISO 178 of the unfoamed and foamed injection moulded article, the stiffness reduction factor of the foamed injection moulded article being reduced by at least 40 compared to an article comprising the same amount of polypropylene polymerised in the presence of a ziegler-natta catalyst.

Background

Polypropylene is used in many applications and is for example a material choice in many fields such as automotive applications, as they can be tailored to the specific purpose required. However, recent demands in the plastics industry tend to be weight savings. Foaming of polymer compounds via injection molding (FIM) technology has received extensive attention in science and industry due to its ability to produce low density parts with high geometric accuracy and improved dimensional stability. Using this technique, a product having a porous core and a solid skin can be shaped in a single operation. Essentially, FIM involves the use of an inert gas that will disperse in the polymer melt or by pre-blending the resins with a chemical blowing (or foaming) agent that releases the inert gas when heated. The bubbles then expand in the melt, filling the mold and creating an internal porous structure. In injection molding of thermoplastics containing blowing agents, the mixture is maintained under sufficient back pressure to confine the gas and prevent premature expansion. Depending on the weight requirements, a specific amount of material will be added and the melt injected into the mold. Unless a sufficiently high equilibrium pressure is applied, the trapped gas expands as soon as the melt/gas mixture enters the empty mold. Obtaining a uniform and high cell density microcellular structure in FIM, which is critical for obtaining better mechanical properties and excellent emissions from expanded plastics, is challenging and can be controlled by process conditions. It is well known to vary the effects of process conditions such as blowing agent content, mold temperature, melt temperature, injection pressure and back pressure to produce high quality bubbles in terms of low skin thickness, small pore size and narrow pore size distribution. However, the impact of polymer design on foam structure and emissions has been rarely studied to date.

Therefore, there is still a need for polypropylene compositions having excellent foamability. Furthermore, it is desirable that these polypropylene compositions have a low volatile content and a good balance of mechanical properties.

Disclosure of Invention

The finding of the present invention is that with specific polypropylene homopolymers it is possible to obtain polypropylene compositions having a combination of excellent foamability with a low volatile content and good mechanical properties.

Accordingly, the present invention relates to a polypropylene composition comprising

a) 45 to 97.5 wt%, based on the total weight of the composition, of a polypropylene homopolymer (H-PP1), the polypropylene homopolymer (H-PP1) having

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 150 to 160 ℃,

ii) in the range of 0.50 to 1.00 mol% of a monomer mixture of¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy,

iii) at least 97.5% of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and

iv) a xylene cold soluble fraction (XCS) determined according ISO 16152 at 23 ℃ equal to or lower than 1.5 wt. -%,

b) from 0 to 55% by weight, based on the total weight of the composition, of polypropylene (PP2),

c) 0 to 30% by weight, based on the total weight of the composition, of a filler (F), and

d) 2.5 to 5 wt%, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, antioxidants and mixtures thereof,

wherein the sum of the amounts of polypropylene homopolymer (H-PP1), polypropylene (PP2), filler (F) and at least one additive in the polypropylene composition is 100.0 wt.%.

According to one embodiment of the invention, the composition comprises, preferably consists of, a) 95 to 97.5 wt. -%, based on the total weight of the composition, of polypropylene homopolymer (H-PP1), and b) 2.5 to 5 wt. -%, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents and mixtures thereof.

According to another embodiment of the invention, the composition comprises, preferably consists of, a) 45 to 52.5 wt. -%, based on the total weight of the composition, of polypropylene homopolymer (H-PP1), b) 45 to 55 wt. -%, based on the total weight of the composition, of polypropylene (PP2), and c) 2.5 to 5 wt. -%, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, and mixtures thereof.

According to yet another embodiment of the invention, the composition has a) a melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 80.0g/10min₂(230 ℃ C.); and/or b) a content of volatile organic compounds of not more than 170 [ mu ] g/g of the composition in the unfoamed injection-molded part; and/or c) a content of volatile organic compounds of not more than 200 μ g/g of the composition in particulate form; and/or d) a glass transition temperature Tg (measured with DMTA according to ISO 6721-7) of 0 ℃ or more, preferably +1 ℃ or more.

According to one embodiment of the invention, the composition comprises 0.1 to 0.5 wt. -% of a nucleating agent, preferably a nucleating agent comprising 1, 2-cyclohexanedicarboxylic acid, based on the total weight of the composition.

According to another embodiment of the present invention, the polypropylene (PP2) is a polypropylene homopolymer (H-PP 2).

According to yet another embodiment of the present invention, the polypropylene homopolymer (H-PP1) and/or the polypropylene (PP2) has a melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 100.0g/10min, preferably in the range of 25.0 to 90.0g/10min₂(230℃)。

According to one embodiment of the invention, the melt flow rate MFR, measured according to ISO 1133, of the polypropylene homopolymer (H-PP1)₂Melt flow Rate MFR measured according to ISO 1133 of (230 ℃) in combination with Polypropylene (PP2)₂The difference (230 ℃) is less than 20.0g/10min, preferably less than 15.0g/10min and most preferably less than 10.0 g/min.

According to another embodiment of the present invention the polypropylene homopolymer (H-PP1) i) is unimodal and/or ii) has a molecular weight distribution Mw/Mn measured according to ISO16014 in the range ≦ 4.0, preferably in the range of 2.0 to 4.0 and most preferably in the range of 2.5 to 4.0.

According to yet another embodiment of the present invention, the polypropylene homopolymer (H-PP1) has i) a melting temperature Tm in the range of 150 to 160 ℃ as measured by Differential Scanning Calorimetry (DSC), ii) in the range of 0.50 to 1.00 mol% of¹³A content of 2,1 erythro-type domain defects determined by C-NMR spectroscopy, iii) at least 97.5% of a crystalline fraction of¹³An isotactic triad fraction (mm) determined by C-NMR spectroscopy, and iv) a xylene cold soluble fraction (XCS) determined according ISO 16152 at 23 ℃ equal to or lower than 1.5 wt.%.

According to one embodiment of the invention the polypropylene (PP2) has i) a melting temperature Tm in the range of 162 to 170 ℃ as measured by Differential Scanning Calorimetry (DSC) and/or ii) 0.10 mol% of¹³A content of 2,1 erythro-type domain defects determined by C-NMR spectroscopy, and/or iii) a content of 2,1 erythro-type domain defects in the range of 95.0 to 98.0%¹³C-An isotactic triad fraction (mm) determined by NMR spectroscopy, and/or iv) a molecular weight distribution Mw/Mn measured according to ISO16014 in the range of ≥ 4.0, and/or v) a xylene cold soluble fraction (XCS) determined according to ISO 16152 at 23 ℃ in the range of 1.5 to 3.5 wt.%.

According to another embodiment of the invention, the composition has a bimodal molecular structure.

According to yet another embodiment of the present invention, the filler (F) is selected from talc, mica, wollastonite, glass fiber, carbon fiber and mixtures thereof.

According to another aspect of the present invention there is provided an injection moulded article comprising the polypropylene composition as defined herein.

According to a further aspect of the present invention there is provided a foamed article, preferably a foamed injection moulded article, comprising the polypropylene composition as defined herein.

According to yet a further aspect, there is provided the use of a polypropylene homopolymer (H-PP1) for reducing the stiffness reduction factor of a foamed injection molded article, the stiffness reduction factor being determined by the difference in flexural modulus measured according to ISO 178 of the unfoamed and foamed injection molded article and the stiffness reduction factor of the foamed injection molded article being reduced by at least 40 compared to an article comprising the same amount of polypropylene polymerized in the presence of a ziegler-natta catalyst, wherein the polypropylene homopolymer (H-PP1) has i) a melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 150 to 160 ℃, ii) a refractive index measured by Differential Scanning Calorimetry (DSC) in the range of 0.50 to 1.00 mol-%¹³A content of 2,1 erythro-type domain defects determined by C-NMR spectroscopy, iii) at least 97.5% of a crystalline fraction of¹³An isotactic triad fraction (mm) determined by C-NMR spectroscopy, and iv) a xylene cold soluble fraction (XCS) determined according ISO 16152 at 23 ℃ equal to or lower than 1.5 wt.%.

Detailed Description

The invention is defined in more detail below.

Polypropylene composition

The polypropylene (PP) composition according to the invention comprises

a) 45 to 97.5 wt%, based on the total weight of the composition, of a polypropylene homopolymer (H-PP1), the polypropylene homopolymer (H-PP1) having

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 150 to 160 ℃,

ii) in the range of 0.50 to 1.00 mol% of a monomer mixture of¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy,

iii) at least 97.5% of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and

iv) a xylene cold soluble fraction (XCS) determined according ISO 16152 at 23 ℃ equal to or lower than 1.5 wt. -%,

b) from 0 to 55% by weight, based on the total weight of the composition, of polypropylene (PP2),

c) 0 to 30% by weight, based on the total weight of the composition, of a filler (F), and

d) 2.5 to 5 wt%, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, antioxidants and mixtures thereof,

wherein the sum of the amounts of polypropylene homopolymer (H-PP1), polypropylene (PP2), filler (F) and at least one additive in the polypropylene composition is 100.0 wt.%.

In a preferred embodiment, the polypropylene composition according to the invention does not comprise further polymers different from the polymers present in the polypropylene (PP) composition, i.e. different from the polypropylene homopolymer (H-PP1) and optionally the polypropylene (PP 2). Typically, if an additional polymer is present, this polymer is the carrier polymer for the additives and thus does not contribute to the improved properties of the claimed polypropylene composition.

Thus, in one embodiment, the polypropylene composition consists of polypropylene homopolymer (H-PP1), optionally polypropylene (PP2), optionally filler (F) and at least one additive, the polypropylene composition may comprise a minor amount of a polymeric carrier material. However, the polymeric carrier material is present in the polypropylene composition in an amount of not more than 2.0 wt. -%, preferably not more than 1.6 wt. -%, based on the total weight of the polypropylene composition.

In one embodiment, it is therefore preferred that the polypropylene composition consists of

a) 45 to 97.5 wt%, based on the total weight of the composition, of a polypropylene homopolymer (H-PP1), the polypropylene homopolymer (H-PP1) having

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 150 to 160 ℃,

ii) in the range of 0.50 to 1.00 mol% of a monomer mixture of¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy,

iii) at least 97.5% of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and

iv) a xylene cold soluble fraction (XCS) determined according ISO 16152 at 23 ℃ equal to or lower than 1.5 wt. -%,

b) from 0 to 55% by weight, based on the total weight of the composition, of polypropylene (PP2),

c) 0 to 30% by weight, based on the total weight of the composition, of a filler (F), and

d) 2.5 to 5 wt%, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, antioxidants and mixtures thereof,

wherein the sum of the amounts of polypropylene homopolymer (H-PP1), polypropylene (PP2), filler (F) and at least one additive in the polypropylene composition is 100.0 wt.%.

Preferably, the polypropylene composition comprises, more preferably consists of,

a) 95 to 97.5 wt%, based on the total weight of the composition, of a polypropylene homopolymer (H-PP1), and

b) 2.5 to 5 weight percent, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, and mixtures thereof.

In an alternative embodiment, the polypropylene composition comprises, preferably consists of,

a) 45 to 52.5 wt%, based on the total weight of the composition, of a polypropylene homopolymer (H-PP1),

b) 45 to 55 wt%, based on the total weight of the composition, of polypropylene (PP2), and

c) 2.5 to 5 weight percent, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, and mixtures thereof.

In another embodiment, the polypropylene composition comprises, preferably consists of,

a) 45 to 80.5 wt%, based on the total weight of the composition, of a polypropylene homopolymer (H-PP1),

b) 15 to 30 wt. -%, based on the total weight of the composition, of polypropylene (PP2),

c) 2 to 20% by weight, based on the total weight of the composition, of a filler (F), and

d) 2.5 to 5 weight percent, based on the total weight of the composition, of at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, and mixtures thereof.

Preferably, the polypropylene composition has a melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 80.0g/10min, more preferably in the range of 25.0 to 80g/10min, such as in the range of 40.0 to 74.0g/10min₂(230℃，2.16kg)。

Additionally or alternatively, the polypropylene composition has a content of volatile organic compounds of not more than 200 μ g/g of the composition in particulate form, preferably not more than 180 μ g/g of the composition in particulate form and most preferably not more than 165 μ g/g of the composition in particulate form.

Additionally or alternatively, the polypropylene composition has a content of volatile organic compounds of not more than 170 μ g/g of the composition in the unfoamed injection molded part, preferably not more than 120 μ g/g of the composition in the unfoamed injection molded part and most preferably not more than 90 μ g/g of the composition in the unfoamed injection molded part.

Additionally or alternatively, the polypropylene composition has a glass transition temperature Tg (measured with DMTA according to ISO 6721-7) of 0 ℃ or higher, preferably +1 ℃ or higher and most preferably in the range of +1 to +10 ℃.

In a preferred embodiment, the polypropylene composition has

a) A melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 80.0g/10min, more preferably in the range of 25.0 to 80g/10min, such as in the range of 40.0 to 74.0g/10min₂(230 ℃, 2.16kg), and/or

b) A content of volatile organic compounds of not more than 170 μ g/g of the composition in the unfoamed injection molded part, preferably not more than 120 μ g/g of the composition in the unfoamed injection molded part and most preferably not more than 90 μ g/g of the composition in the unfoamed injection molded part, and/or

c) (ii) a volatile organic compound content of no more than 200 μ g/g of the composition in particulate form, preferably no more than 180 μ g/g of the composition in particulate form and most preferably no more than 165 μ g/g of the composition in particulate form; and/or

d) A glass transition temperature Tg (measured with DMTA according to ISO 6721-7) of 0 ℃ or higher, preferably +1 ℃ or higher and most preferably in the range of +1 to +10 ℃.

For example, the polypropylene (PP) composition has

a) A melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 80.0g/10min, more preferably in the range of 25.0 to 80g/10min, such as in the range of 40.0 to 74.0g/10min₂(230 ℃, 2.16kg), or

b) A content of volatile organic compounds of not more than 170 μ g/g of the composition in the unfoamed injection molded part, preferably not more than 120 μ g/g of the composition in the unfoamed injection molded part and most preferably not more than 90 μ g/g of the composition in the unfoamed injection molded part, or

c) (ii) a volatile organic compound content of no more than 200 μ g/g of the composition in particulate form, preferably no more than 180 μ g/g of the composition in particulate form and most preferably no more than 165 μ g/g of the composition in particulate form; or

d) A glass transition temperature Tg (measured with DMTA according to ISO 6721-7) of 0 ℃ or higher, preferably +1 ℃ or higher and most preferably in the range of +1 to +10 ℃.

For example, the polypropylene (PP) composition has

a) A melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 80.0g/10min, more preferably in the range of 25.0 to 80g/10min, such as in the range of 40.0 to 74.0g/10min₂(230 ℃, 2.16kg), and

b) a content of volatile organic compounds of not more than 170 μ g/g of the composition in the unfoamed injection molded part, preferably not more than 120 μ g/g of the composition in the unfoamed injection molded part and most preferably not more than 90 μ g/g of the composition in the unfoamed injection molded part, and

c) (ii) a volatile organic compound content of no more than 200 μ g/g of the composition in particulate form, preferably no more than 180 μ g/g of the composition in particulate form and most preferably no more than 165 μ g/g of the composition in particulate form; and

d) a glass transition temperature Tg (measured with DMTA according to ISO 6721-7) of 0 ℃ or higher, preferably +1 ℃ or higher and most preferably in the range of +1 to +10 ℃.

Preferably, the polypropylene composition may be unimodal or multimodal, such as bimodal. However, it is preferred that the polypropylene composition has a bimodal molecular structure.

It will be appreciated that the polypropylene composition imparts an advantageous stiffness reduction factor to the foamed injection molded article. It is therefore preferred that the stiffness reduction factor of the foamed injection moulded article is reduced by at least 40 as determined by the difference in flexural modulus measured according to ISO 178 of the unfoamed and foamed injection moulded article and compared to an article comprising the same amount of polypropylene polymerized in the presence of a ziegler-natta catalyst.

The polypropylene composition according to the present invention can be compounded and pelletized using any of a variety of compounding and blending machines and methods well known and commonly used in the resin compounding art.

For blending the individual components of the polypropylene composition of the invention, conventional compounding or blending equipment may be used, such as a Banbury mixer, a two-roll rubber mill, a Brookfield blending kneader or a twin-screw extruder. The polypropylene composition recovered from the extruder/mixer is usually in the form of pellets. These particles are then preferably further processed, for example by injection moulding, to produce articles and products of the composition of the invention.

Hereinafter, the respective components of the polypropylene composition are described in more detail.

Polypropylene homopolymer (H-PP1)

The polypropylene composition must comprise polypropylene homopolymer (H-PP1) in an amount of 45 to 97.5 wt. -%, based on the total weight of the polypropylene composition. Preferably, the polypropylene composition comprises polypropylene homopolymer (H-PP1) in an amount of 80 to 97.5 wt. -%, such as in the range of 95 to 97.5 wt. -%, based on the total weight of the polypropylene composition.

Preferably, the polypropylene homopolymer (H-PP1) has a melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 100.0g/10min, more preferably in the range of 25.0 to 90.0g/10min₂(230℃，2.16kg)。

The polypropylene homopolymer (H-PP1) may be unimodal or multimodal, such as bimodal. Preferably, however, the polypropylene homopolymer (H-PP1) is unimodal.

The expressions "monomodal", "bimodal" and "multimodal" as used herein refer to the modality of a polymer, i.e. the morphology of its molecular weight distribution curve, which is a plot of the molecular weight fraction as a function of its molecular weight.

When the polypropylene homopolymer (H-PP1) is unimodal with respect to molecular weight distribution, it may be prepared in a single stage process (e.g., a slurry or gas phase process in a slurry or gas phase reactor). Preferably, the unimodal polypropylene homopolymer (H-PP1) is polymerized by slurry polymerization. Alternatively, unimodal polypropylene homopolymer (H-PP1) is produced in a multistage process, using process conditions in each stage that result in similar polymer properties.

The term "polypropylene homopolymer (H-PP 1)" as used herein relates to a polypropylene consisting essentially (i.e. more than 98.0 wt. -%, preferably more than 99.0 wt. -%, even more preferably more than 99.5 wt. -%, still more preferably at least 99.8 wt%) of propylene units. In a preferred embodiment, only propylene units are detectable in the polypropylene homopolymer (H-PP 1).

It is to be understood that the polypropylene homopolymer (H-PP1) preferably has a Xylene Cold Soluble (XCS) content equal to or lower than 1.5 wt. -%, based on the total weight of the polypropylene homopolymer (H-PP 1). For example, the polypropylene homopolymer (H-PP1) has a Xylene Cold Soluble (XCS) content in the range of 0.1 to 1.5 wt. -%, preferably in the range of 0.1 to 1.4 wt. -%, based on the total weight of the polypropylene homopolymer (H-PP 1).

A further requirement of the present invention is that the polypropylene homopolymer (H-PP1) has a relatively high melting temperature T_m. More precisely, it is required that the polypropylene homopolymer (H-PP1) has a melting temperature T, measured by Differential Scanning Calorimetry (DSC), in the range of 150 to 160 ℃_m. For example, the polypropylene homopolymer (H-PP1) has a melting temperature T as measured by Differential Scanning Calorimetry (DSC) in the range of 152 to 158 ℃, preferably in the range of 152 to 156 ℃_m。

Higher melting temperature T_mIndicating that the polypropylene homopolymer (H-PP1) has a lower regio-defect content. Preferably, the polypropylene homopolymer (H-PP1) has a molecular weight in the range of 0.50 to 1.00 mol%¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy. More preferably, the polypropylene homopolymer (H-PP1) has a molecular weight in the range of 0.55 to 0.80 mol% and most preferably in the range of 0.60 to 0.80 mol%¹³2,1 erythro-type domain defects as determined by C-NMR spectroscopy.

Additionally or alternatively, the polypropylene homopolymer (H-PP1) has a composition of at least 97.5%¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy. For example, the polypropylene homopolymer (H-PP1) has a molecular weight of at least 98.5%, more preferably at least 99.0%, such as in the range of 99.0 to 99.5%Inside the enclosure is provided with¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy.

It is therefore desirable that the polypropylene homopolymer (H-PP1) has

i) A melting temperature Tm as measured by Differential Scanning Calorimetry (DSC) in the range of 150 to 160 ℃, preferably in the range of 152 to 158 ℃ and most preferably in the range of 152 to 156 ℃,

ii) in the range of 0.50 to 1.00 mol%, preferably in the range of 0.55 to 0.80 mol% and most preferably in the range of 0.60 to 0.80 mol% of¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy,

iii) at least 97.5%, preferably at least 98.5%, more preferably at least 99.0%, such as in the range of 99.0 to 99.5% of a monomer mixture consisting of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and

iv) a xylene cold soluble fraction (XCS) determined according to ISO 16152 at 23 ℃ equal to or lower than 1.5 wt. -%, preferably in the range of 0.1 to 1.5 wt. -% and most preferably in the range of 0.1 to 1.4 wt. -%.

Preferably, the polypropylene homopolymer (H-PP1) has a weight average molecular weight (Mw) in the range of 80 to 500kg/mol, preferably in the range of 100 to 400kg/mol, more preferably in the range of 120 to 350k/mol, and/or a number average molecular weight (Mn) of 20 to 200kg/mol, more preferably 50 to 150kg/mol (determined by GPC according to ISO 16014).

Preferably, the polypropylene homopolymer (H-PP1) has a molecular weight distribution Mw/Mn, measured according to ISO16014, of ≦ 4.0, preferably in the range of 1.5 to 4.0, more preferably in the range of 2.0 to 4.0 and most preferably in the range of 2.5 to 4.0.

Thus, in one embodiment, a polypropylene homopolymer (H-PP1)

i) Is unimodal, and/or

ii) has a molecular weight distribution Mw/Mn, measured according to ISO16014, in the range ≦ 4.0, preferably in the range from 2.0 to 4.0 and more preferably in the range from 2.5 to 4.0.

For example, polypropylene homopolymer (H-PP1)

i) Is unimodal, or

ii) has a molecular weight distribution Mw/Mn, measured according to ISO16014, in the range ≦ 4.0, preferably in the range from 2.0 to 4.0 and more preferably in the range from 2.5 to 4.0.

Alternatively, a polypropylene homopolymer (H-PP1)

i) Is unimodal, and

ii) has a molecular weight distribution Mw/Mn, measured according to ISO16014, in the range ≦ 4.0, preferably in the range from 2.0 to 4.0 and more preferably in the range from 2.5 to 4.0.

The polypropylene homopolymer (H-PP1) is preferably produced by a single stage or multistage process polymerization of propylene, such as bulk polymerization, gas phase polymerization, slurry polymerization, solution polymerization or a combination thereof. The polypropylene homopolymer (H-PP1) can be made in a loop reactor or a combination of loop and gas phase reactors. These methods are well known to those skilled in the art.

To overcome the disadvantages of the prior art, it is understood that the polypropylene homopolymer (H-PP1) must be polymerized in the presence of a single site catalyst.

Preferably, the catalyst system comprises a catalyst component according to formula (I)

Wherein

M is zirconium or hafnium;

each X is independently a sigma-donor ligand;

l is formula- (ER)¹⁰ ₂)_y-a bridge of;

y is 1 or 2;

e is C or Si;

each R¹⁰Independently is C₁To C₂₀A hydrocarbyl radical, tri (C)₁To C₂₀Alkyl) silyl group, C₆To C₂₀Aryl radical, C₇To C₂₀Aralkyl radical or C₇To C₂₀An alkylaryl group, or L isAlkylene groups such as methylene or ethylene;

R¹are each independently the same or different from each other and are CH₂-R¹¹Group, R¹¹Is H or straight or branched C₁To C₆Alkyl radical, C₃To C₈Cycloalkyl radical, C₆To C₁₀An aryl group;

R³、R⁴and R⁵Each independently of the other, identical or different from each other, and is H or C which is linear or branched₁To C₆Alkyl radical, C₇To C₂₀Aralkyl radical, C₇To C₂₀Alkylaryl group or C₆To C₂₀Aryl group, provided that there are a total of four or more R's different from H³、R⁴And R⁵Group, R³、R⁴And R⁵Is not a tert-butyl group;

R⁷and R⁸Each independently the same or different from each other, and is H, CH₂-R¹²Group, R¹²Is H or straight or branched C₁To C₆Alkyl radical, SiR¹³ ₃、GeR¹³ ₃、OR¹³、SR¹³、NR¹³ ₂，

Wherein

R¹³Is straight-chain or branched C₁To C₆Alkyl radical, C₇To C₂₀Alkylaryl group and C₇To C₂₀Aralkyl radical or C₆To C₂₀An aryl group.

The catalyst system may also include

(ii) A cocatalyst system comprising a boron-containing cocatalyst and an aluminoxane cocatalyst;

it should be emphasized that the use of such a cocatalyst may not be necessary in some cases. The catalyst system of the present invention can be used in unsupported or solid form. The catalyst system of the present invention can be used as a homogeneous catalyst system or a heterogeneous catalyst system.

The catalyst system of the invention in solid form, preferably in the form of solid particles, can be supported on an external support material, such as silica or alumina, or, in a particularly preferred embodiment, be free of external support, while still in solid form. For example, the solid catalyst system can be obtained by a process in which

(a) Forming a liquid/liquid emulsion system comprising a solution of catalyst components (i) and (ii) dispersed in a solvent to form dispersed droplets; and

(b) solid particles are formed by solidifying the dispersed droplets.

Specific complexes of the invention include:

rac-trans-dimethylsilylene [ 2-methyl-4- (4-tert-butylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (4-tert-butylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl,

rac-trans-dimethylsilylene [ 2-isobutyl-4- (4-tert-butylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (4-tert-butylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl,

rac-trans-dimethylsilylene [ 2-neopentyl-4- (4-tert-butylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (4-tert-butylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl,

rac-trans-dimethylsilylene [ 2-benzyl-4- (4-tert-butylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (4-tert-butylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl,

rac-trans-dimethylsilylene [ 2-cyclohexylmethyl-4- (4-tert-butylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (4-tert-butylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl,

rac-trans-dimethylsilylene [ 2-methyl-4- (3, 5-dimethylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (3, 5-dimethylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl,

rac-trans-dimethylsilylene [ 2-isobutyl-4- (3, 5-dimethylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (3, 5-dimethylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl,

rac-trans-dimethylsilylene [ 2-neopentyl-4- (3, 5-dimethylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (3, 5-dimethylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl,

rac-trans-dimethylsilylene [ 2-benzyl-4- (3, 5-dimethylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (3, 5-dimethylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl, and

rac-trans-dimethylsilylene [ 2-cyclohexylmethyl-4- (3, 5-dimethylphenyl) -5,6, 7-trihydro-s-indacen-1-yl ] [ 2-methyl-4- (3, 5-dimethylphenyl) -5-methoxy-6-tert-butylindenyl zirconium dichloride or dimethyl.

The catalyst is described in particular in WO2015/011135, which is incorporated herein by reference. A particularly preferred catalyst is catalyst No. 3 of WO 2015/011135. The preparation of metallocenes is described in WO2013/007650, incorporated herein by reference. A complex preparation of a particularly preferred catalyst is described in WO2013/007650 as E2.

For the avoidance of doubt, any of the definitions given above for a substituent may be combined with any other definitions broadly or narrowly defined for any other substituent.

Throughout the above disclosure, where a narrow definition of a substituent is given, it is considered that the narrow definition is disclosed along with all broad and narrow definitions of other substituents in the present application.

The ligands required to form the complex and thus the catalyst/catalyst system of the invention can be synthesized by any method, and an experienced organic chemist can design various synthetic schemes to make the necessary ligand materials. For example, WO2007/116034 discloses the necessary chemicals. Synthetic schemes can also be found in general in WO2002/02576, WO2011/135004, WO2012/084961, WO2012/001052, WO2011/076780 and WO 2015/158790. The examples section also provides the skilled person with adequate guidance.

As mentioned above, a cocatalyst is not always necessary. However, when used, the cocatalyst system includes a boron-containing cocatalyst in combination with an aluminoxane cocatalyst.

The aluminoxane cocatalyst can be one of the formulae (II):

wherein n is typically 6 to 20 and R has the following meaning.

Aluminoxanes are formed by partial hydrolysis of an organoaluminum compound, such as, for example, of the formula AlR₃、AlR₂Y and Al₂R₃Y₃Wherein R may be, for example, C₁To C₁₀Alkyl (preferably C)₁To C₅Alkyl) or C₃To C₁₀Cycloalkyl radical, C₇To C₁₂Aralkyl or alkaryl radicals and/or phenyl or naphthyl radicals, and wherein Y may be hydrogen, halogen (preferably chlorine or bromine) or C₁To C₁₀Alkoxy, preferably methoxy or ethoxy. The resulting oxygen-containing aluminoxanes are generally not pure compounds but mixtures of oligomers of the formula (II).

The preferred aluminoxane is Methylaluminoxane (MAO). Since the aluminoxanes used according to the invention as cocatalysts are not pure compounds owing to the way in which they are prepared, the molar concentration of the aluminoxane solution is based in the following on its aluminum content.

In accordance with the present invention, the aluminoxane cocatalyst is used in combination with the boron-containing cocatalyst, i.e., the aluminoxane cocatalyst is generally not necessary when the cocatalyst system or cocatalyst is present.

Boron-based cocatalysts of interest include those of formula (III)

BY₃ (III)

Wherein Y is independently the same or can be different and is a hydrogen atom, an alkyl group containing from 1 to about 20 carbon atoms, an aryl group containing from 6 to about 15 carbon atoms, an alkaryl, aralkyl, haloalkyl or haloaryl group each having from 1 to 10 carbon atoms in the alkyl group and from 6 to 20 carbon atoms in the aryl group or each having fluorine, chlorine, bromine or iodine. Preferred examples of Y are methyl, propyl, isopropyl, isobutyl or trifluoromethyl, unsaturated groups such as aryl or haloaryl groups, such as phenyl, tolyl, benzyl groups, p-fluorophenyl, 3, 5-difluorophenyl, pentachlorophenyl, pentafluorophenyl, 3,4, 5-trifluorophenyl and 3, 5-bis (trifluoromethyl) phenyl. Preferred options are trifluoroborane, triphenylborane, tris (4-fluorophenyl) borane, tris (3, 5-difluorophenyl) borane, tris (4-fluoromethylphenyl) borane, tris (2,4, 6-trifluorophenyl) borane, tris (pentafluorophenyl) borane, tris (tolyl) borane, tris (3, 5-dimethyl-phenyl) borane, tris (3, 5-difluorophenyl) borane and/or tris (3,4, 5-trifluorophenyl) borane.

Particular preference is given to tris (pentafluorophenyl) borane.

Borates, i.e. compounds containing borate 3+ ions, may be used. Such ionic cocatalysts preferably comprise non-coordinating anions such as tetrakis (pentafluorophenyl) borate and tetraphenylborate. Suitable counterions are protonated amine or aniline derivatives, such as methylammonium, anilinium, dimethylammonium, diethylammonium, N-methylammonium, diphenylammonium, N-dimethylanilinium, trimethylammonium, triethylammonium, tri-N-butylammonium, methyldiphenylammonium, pyridinium, p-bromo-N, N-dimethylanilinium or p-nitro-N, N-dimethylanilinium.

Preferred ionic compounds that may be used according to the present invention include:

triethylammonium tetra (phenyl) borate, to which is added,

tributylammonium tetra (phenyl) borate, a salt of the compound,

trimethylammonium tetra (tolyl) borate,

tributylammonium tetra (tolyl) borate,

tributylammonium tetrakis (pentafluorophenyl) borate,

tripropylammonium tetrakis (dimethylphenyl) borate,

tributylammonium tetrakis (trifluoromethylphenyl) borate,

tributylammonium tetrakis (4-fluorophenyl) borate,

n, N-dimethylcyclohexylammonium tetrakis (pentafluorophenyl) borate,

n, N-dimethylbenzylammonium tetrakis (pentafluorophenyl) borate,

n, N-dimethylanilinium tetra (phenyl) borate,

n, N-diethylanilinium tetra (phenyl) borate,

n, N-dimethylanilinium tetrakis (pentafluorophenyl) borate,

n, N-di (propyl) ammonium tetrakis (pentafluorophenyl) borate,

bis (cyclohexyl) ammonium tetrakis (pentafluorophenyl) borate,

triphenylphosphonium tetra (phenyl) borate,

triethylphosphonium tetra (phenyl) borate,

diphenylphosphonium tetra (phenyl) borate,

tris (methylphenyl) phosphonium tetra (phenyl) borate,

tris (dimethylphenyl) phosphonium tetra (phenyl) borate,

triphenylcarbenium tetrakis (pentafluorophenyl) borate,

or ferrocenium tetrakis (pentafluorophenyl) borate.

Preferably triphenylcarbenium tetrakis (pentafluorophenyl) borate,

n, N-dimethylcyclohexylammonium tetrakis (pentafluorophenyl) ate, or

N, N-dimethylbenzylammonium tetrakis (pentafluorophenyl) borate.

Suitable amounts of cocatalyst are known to the skilled worker.

The molar ratio of boron to metal ions in the metallocene may be in the range of 0.5: 1 to 10: 1mol/mol, preferably 1:1 to 10: 1mol/mol, in particular 1:1 to 5: in the range of 1 mol/mol.

The molar ratio of Al in the aluminoxane to the metal ion in the metallocene can be in the range of 1:1 to 2000: 1mol/mol, preferably 10: 1 to 1000: 1mol/mol and more preferably 50: 1 to 500: in the range of 1 mol/mol.

The catalysts of the invention can be used in supported or unsupported form. The particulate support material used is preferably an organic or inorganic material such as silica, alumina or zirconia or a mixed oxide such as silica-alumina, in particular silica, alumina or silica-alumina. The use of a silica support is preferred. The skilled worker knows the steps required for supporting the metallocene catalyst.

It is particularly preferred that the carrier is a porous material so that the complex can be loaded into the pores of the carrier, for example using methods similar to those described in WO94/14856(Mobil), WO95/12622(Borealis) and WO 2006/097497. The particle size is not critical but is preferably in the range of 5 to 200 μm, more preferably 20 to 80 μm. The use of these vectors is conventional in the art.

In an alternative embodiment, no carrier is used at all. Such catalyst systems may be prepared in solution (e.g., in an aromatic solvent such as toluene) by contacting the metallocene (as a solid or as a solution) with the cocatalyst (e.g., methylaluminoxane previously dissolved in an aromatic solvent), or may be prepared by sequentially adding the dissolved catalyst components to the polymerization medium.

In a particularly preferred embodiment, no external support is used, but the catalyst is still present in the form of solid particles. Thus, no external support material is employed, such as an inert organic or inorganic support, e.g., the silica described above.

In order to provide the catalyst of the invention in solid form without the use of an external carrier, it is preferred to use a liquid/liquid emulsion system. The process involves forming dispersed catalyst components (i) and (ii) in a solvent and solidifying the dispersed droplets to form solid particles.

In particular, the process involves preparing a solution of one or more catalyst components; dispersing the solution in a solvent to form an emulsion, wherein the one or more catalyst components are present in droplets of the dispersed phase; the catalyst components are immobilized in dispersed droplets in the absence of an external particulate porous support to form solid particles comprising the catalyst, and optionally recovering the particles.

The process enables the manufacture of active catalyst particles having improved morphology (e.g. having predetermined spherical shape, surface properties and particle size) without the use of any added external porous support material such as inorganic oxides, e.g. silica. The term "preparing a solution of one or more catalyst components" means that the catalyst-forming compounds can be combined in one solution that is dispersed in an immiscible solvent, or alternatively, for each portion of the catalyst-forming compounds, at least two separate catalyst solutions are prepared and then subsequently dispersed in a solvent.

In a preferred method of forming the catalyst, for each or a portion of the catalyst, at least two separate solutions may be prepared and then dispersed sequentially in immiscible solvents.

More preferably, a solution comprising a complex of a transition metal compound and a cocatalyst is combined with a solvent to form an emulsion, wherein the inert solvent forms a continuous liquid phase and the solution comprising the catalyst component forms a dispersed phase (discontinuous phase) in the form of dispersed droplets. The droplets are then solidified to form solid catalyst particles, and the solid particles are separated from the liquid and, optionally, washed and/or dried. The solvent forming the continuous phase may be immiscible with the catalyst solution at least under the conditions (e.g., temperature) used during the dispersing step.

The term "immiscible with the catalyst solution" means that the solvent (continuous phase) is completely or partially immiscible, i.e. not completely miscible, with the dispersed phase solution.

Preferably, the solvent is inert with respect to the compounds of the catalyst system to be produced. A complete disclosure of the necessary methods can be found in WO 03/051934.

The inert solvent must be chemically inert at least under the conditions (e.g., temperature) used during the dispersing step. Preferably, the solvent of the continuous phase does not contain any significant amount of catalyst-forming compounds dissolved therein. Thus, solid particles of catalyst are formed in the droplets from the compound originating from the dispersed phase (i.e. provided to the emulsion, in solution dispersed into the continuous phase).

The terms "immobilization" and "curing" are used interchangeably herein for the same purpose (i.e., for forming free-flowing solid catalyst particles in the absence of an external porous particle support such as silica). Solidification thus occurs within the droplets. This step may be carried out in various ways as disclosed in this WO 03/051934. Preferably, the curing is caused by an external stimulus to the emulsion system, such as a temperature change to cause curing. Thus, in this step, the catalyst component remains "fixed" within the formed solid particles. It is also possible that one or more catalyst components may participate in the curing/fixing reaction.

Thus, compositionally uniform particles of solids having a predetermined particle size range can be obtained.

In addition, the particle size of the catalyst particles of the present invention can be controlled by the size of the droplets in the solution, and spherical particles having a uniform particle size distribution can be obtained.

The process is also industrially advantageous in that it enables the preparation of solid particles in a one-pot process. Continuous or semi-continuous processes may also be used to produce the catalyst.

In the polymerization process according to the invention, fresh catalyst is preferably introduced only into the first reactor or, if present, into the prepolymerization reactor or vessel, i.e. no fresh catalyst is introduced into the second reactor or any further reactor present upstream of the first reactor or upstream of the prepolymerization vessel. Fresh catalyst means the original catalyst species or the original catalyst species that has undergone prepolymerization.

Polypropylene (PP2)

The polypropylene composition may comprise polypropylene (PP2) in an amount of 0 to 55 wt. -%, based on the total weight of the polypropylene composition.

In one embodiment, the polypropylene homopolymer (H-PP1) is the only polymer component in the polypropylene composition. In other words, the polypropylene composition is free of polypropylene (PP 2).

In an alternative embodiment, the polypropylene composition comprises polypropylene (PP 2). In this case, it is preferred that the polypropylene composition has a bimodal molecular structure.

If present, the polypropylene composition comprises polypropylene (PP2) in an amount preferably in the range of from 30 to 55 wt. -%, such as in the range of from 45 to 55 wt. -%, based on the total weight of the polypropylene composition.

In the present invention, the term "polypropylene (PP 2)" comprises polypropylene homopolymer and/or polypropylene copolymer.

Furthermore, the term "propylene copolymer" encompasses polypropylene random copolymers, heterophasic polymers and mixtures thereof.

As known to the skilled person, random polypropylene copolymers are different from heterophasic polypropylenes, which are polypropylenes comprising a propylene homopolymer or random copolymer matrix component (1) and propylene with one or more of ethylene and C₄To C₈Propylene copolymer of an elastomeric copolymer component (2) of an alpha-olefin copolymer, wherein the elastomeric (amorphous) copolymer component (2) is dispersed in the propylene homopolymer or random copolymer matrix polymer (1).

In one embodiment of the invention the polypropylene (PP2) present in the polypropylene composition is a polypropylene homopolymer (H-PP2) and/or a polypropylene copolymer (C-PP 2). For example, the polypropylene composition comprises a polypropylene homopolymer (H-PP2) or a polypropylene copolymer (C-PP 2).

In a particular embodiment, the polypropylene composition comprises polypropylene homopolymer (H-PP2) as polypropylene (PP 2).

The term "polypropylene homopolymer (H-PP 2)" as used herein relates to a polypropylene consisting essentially (i.e. more than 98.0 wt. -%, preferably more than 99.0 wt. -%, even more preferably more than 99.5 wt. -%, still more preferably at least 99.8 wt%) of propylene units. In a preferred embodiment, only propylene units are detectable in the polypropylene homopolymer (H-PP 2).

Preferably, the polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has a melt flow rate MFR measured according to ISO 1133 in the range of 15.0 to 100.0g/10min, more preferably in the range of 25.0 to 90.0g/10min₂(230℃，2.16kg)。

It will be appreciated that the melt flow rate MFR, measured according to ISO 1133, of the polypropylene homopolymer (H-PP1)₂Melt flow Rate MFR, measured according to ISO 1133, of (230 ℃) Polypropylene (PP2), preferably Polypropylene homopolymer (H-PP2)₂The difference (230 ℃) is less than 20.0g/10min, preferably less than 15.0g/10min and most preferably less than 10.0 g/min. For example, the melt flow rate MFR, measured according to ISO 1133, of a polypropylene homopolymer (H-PP1)₂Melt flow Rate MFR, measured according to ISO 1133, of (230 ℃) Polypropylene (PP2), preferably Polypropylene homopolymer (H-PP2)₂The difference (230 ℃) is 1.0 to 10.0 g/min.

The polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), may be unimodal or multimodal, e.g.bimodal. However, it is preferred that the polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), is unimodal.

The expressions "monomodal", "bimodal" and "multimodal" as used herein refer to the modality of a polymer, i.e. the morphology of its molecular weight distribution curve, which is a plot of the molecular weight fraction as a function of its molecular weight

It is to be understood that the polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has a Xylene Cold Soluble (XCS) content in the range of 1.5 to 3.5 wt. -%, preferably in the range of 1.5 to 3.0 wt. -%, based on the total weight of the polypropylene (PP2), preferably polypropylene homopolymer (H-PP 2).

It is further preferred that the polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has a relatively high melting temperature T_m. More precisely, it is preferred that the polypropylene (PP2), preferably the polypropylene homopolymer (H-PP2), has a melting temperature T higher than the melting temperature of the polypropylene homopolymer (H-PP1)_m. For example, polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has a melting temperature T, as measured by Differential Scanning Calorimetry (DSC), in the range of 162 to 170 ℃, preferably in the range of 162 to 168 ℃_m。

Higher melting temperature T_mIt is indicated that polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has a rather low regio-defect content. Preference is given toOf polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), having a molar percentage of at most 0.10%, preferably 0.0%¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy. As is well known in the art, the polypropylene having such an amount of 2, 1-erythro regio defects is preferably produced with a Ziegler-Natta catalyst. Thus, polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), is preferably produced using Ziegler-Natta catalysts.

Additionally or alternatively, the polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has a composition in the range of 95.0 to 98.0%¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy.

Preferably, the polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has a weight average molecular weight (Mw) in the range of 80 to 500kg/mol, preferably in the range of 100 to 400kg/mol, more preferably in the range of 120 to 350k/mol, and/or a number average molecular weight (Mn) of 20 to 200kg/mol, more preferably 50 to 150kg/mol (determined by GPC according to ISO 16014).

Preferably, the polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has a molecular weight distribution Mw/Mn measured according to ISO16014 of ≧ 4.0, preferably in the range from 4.0 to 8.0 and most preferably in the range from 4.0 to 7.0.

Additionally or alternatively, polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has a density in the range of 0.900 to 0.910g/cm³A density within the range of (1).

Thus, in one embodiment, the polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 162 to 170 ℃, preferably in the range of 162 to 168 ℃, and/or

ii) less than or equal to 0.10 mol% of¹³The content of 2,1 erythro-type domain defects determined by C-NMR spectroscopy, and/or

iii) in the range of 95.0 to 98.0% of a compound of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and/or

iv) a molecular weight distribution Mw/Mn, measured according to ISO16014, in the range ≥ 4.0, preferably in the range from 4.0 to 8.0 and most preferably in the range from 4.0 to 7.0, and/or

v) a xylene cold soluble fraction (XCS) determined according to ISO 16152 at 23 ℃ in the range of 1.5 to 3.5 wt. -%, preferably in the range of 1.5 to 3.0 wt. -%.

For example, polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 162 to 170 ℃, preferably in the range of 162 to 168 ℃, or

ii) less than or equal to 0.10 mol% of¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy, or

iii) in the range of 95.0 to 98.0% of a compound of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, or

iv) a molecular weight distribution Mw/Mn, measured according to ISO16014, in the range ≥ 4.0, preferably in the range from 4.0 to 8.0 and most preferably in the range from 4.0 to 7.0, or

v) a xylene cold soluble fraction (XCS) determined according to ISO 16152 at 23 ℃ in the range of 1.5 to 3.5 wt. -%, preferably in the range of 1.5 to 3.0 wt. -%.

Alternatively, the polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), has

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 162 to 170 ℃, preferably in the range of 162 to 168 ℃, and

ii) less than or equal to 0.10 mol% of¹³The content of 2,1 erythro-type domain defects determined by C-NMR spectroscopy, and

iii) in the range of 95.0 to 98.0% of a compound of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and

iv) a molecular weight distribution Mw/Mn, measured according to ISO16014, in the range ≥ 4.0, preferably in the range from 4.0 to 8.0 and most preferably in the range from 4.0 to 7.0, and

v) a xylene cold soluble fraction (XCS) determined according to ISO 16152 at 23 ℃ in the range of 1.5 to 3.5 wt. -%, preferably in the range of 1.5 to 3.0 wt. -%.

Polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), is preferably produced by a single-stage or multistage process polymerization of propylene, such as bulk polymerization, gas phase polymerization, slurry polymerization, solution polymerization, or combinations thereof. Polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), can be made in a loop reactor or in a combination loop and gas phase reactor. These methods are well known to those skilled in the art.

In order to overcome the drawbacks of the prior art, it is understood that polypropylene (PP2), preferably polypropylene homopolymer (H-PP2), is preferably polymerized in the presence of ziegler-natta catalysts known to the skilled person.

Filler (F)

In addition, the polypropylene composition according to the present invention may comprise the filler (F) in an amount of 0 to 30.0 wt. -%, based on the total weight of the polypropylene composition.

Preferably, the polypropylene composition comprises the filler (F) in an amount of 2 to 20 wt. -%, such as in the range of 3 to 15 wt. -%, based on the total weight of the polypropylene composition.

In a particular embodiment, the polypropylene composition is free of filler (F).

Preferably, the filler (F) is a mineral filler (F).

If present, the filler (F) is preferably selected from talc, mica, wollastonite, glass fiber, carbon fiber and mixtures thereof.

In general, the filler (F) may have a particle size d in the range from 5 to 30 μm, preferably in the range from 5 to 25 μm, more preferably in the range from 5 to 20 μm₅₀。

Preferred filler (F) is talc. Preferably, the particle size d is used₅₀Talc in the range of 0.1 to 10 μm, preferably in the range of 0.2 to 6.0 μm, more preferably in the range of 0.3 to 4.0 μm, as filler (F). Most preferably, talc is used as sole filler (F). Still more preferably, the talc used has a top cut particle size (root) of 0.8 to 50 μm, preferably 1.0 to 25 μm and most preferably 1.2 to 20 μmAccording to ISO 787-7, 95% of the particles are below this size).

At least one additive

It is claimed that the polypropylene composition comprises at least one additive in an amount in the range of from 2.5 to 5 wt. -%, based on the total weight of the composition. The at least one additive is selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, nucleating agents, blowing agents, antioxidants, and mixtures thereof.

It should be noted that the term "at least one" additive in the meaning of the present invention means that the additive comprises one or more additives. In one embodiment, the additive is thus an additive. Optionally, the additive comprises two or more (such as two or three) additives.

Preferably, the additives include two or more (such as two or three) additives.

The term "additive" also includes additives provided as a masterbatch comprising the polymeric carrier material discussed above.

It should be understood that the polypropylene composition preferably comprises a nucleating agent. Thus, it is preferred that the polypropylene composition comprises a nucleating agent and one or more further additives selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, blowing agents, antioxidants and mixtures thereof.

For example, the polypropylene composition preferably comprises a nucleating agent, more preferably an alpha-nucleating agent. Even more preferred polypropylene compositions according to the present invention are free of beta-nucleating agents. Thus, the nucleating agent is preferably selected from the group consisting of

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

(ii) dibenzylidene sorbitol (e.g. 1,3:2,4 dibenzylidene sorbitol) and C₁To 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 (nonitol) -derivatives, such as1,2, 3-trideoxy-4, 6:5, 7-bis-O- [ (4-propylphenyl) methylene]-a 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 ] (aluminum-hydroxy-bis [2,2'-methylene-bis (4, 6-di-t-butylphenyl) phosphate ], or 2,2' -methylene-bis (4, 6-di-tert-butylphenyl) phosphate) ], and

(iv) polymers of vinylcycloalkanes and vinylalkane polymers, and

(v) mixtures thereof.

Preferably, the alpha-nucleating agent is a nucleating agent comprising 1, 2-cyclohexanedicarboxylic acid. Commercially available alpha-nucleating agents that may be used in the compositions of the present invention are, for example, Irgaclear XT 386(N- [3, 5-bis- (2, 2-dimethyl-propionylamino) -phenyl ] -2, 2-dimethylpropionamide) from Ciba specialty Chemicals, Hyperform HPN-68L and Hyperform HPN-20E from Milliken & Company.

In one embodiment, the polypropylene composition comprises from 0.1 to 0.5 wt% of a nucleating agent, based on the total weight of the composition. Preferably, the polypropylene composition comprises 0.1 to 0.5 wt% based on the total weight of the composition of a nucleating agent comprising 1, 2-cyclohexanedicarboxylic acid.

Additionally or alternatively, the polypropylene composition comprises a blowing agent.

Throughout the present invention, the term "blowing agent" refers to an agent capable of generating a cellular structure in the polypropylene composition during foaming. Suitable blowing agents include, for example, bicarbonates, preferably bicarbonates, and polyolefin carriers. Such blowing agents are commercially available from, for example, EIWA CHEMICAL ind.

The polypropylene composition of the present invention comprises a blowing agent preferably in an amount of less than 10 wt. -%, more preferably of from 1 to 7 wt. -% and most preferably of from 1.5 to 3 wt. -%, based on the total weight of the polypropylene composition.

Typically, such Additives are commercially available and are described, for example, in "plastics Additives Handbook", 5 th edition, 2001, of Hans Zweifel.

In a preferred embodiment, the polypropylene composition comprises a nucleating agent and a blowing agent and optionally at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, antioxidants and mixtures thereof.

Preferably, the polypropylene composition comprises a nucleating agent and a blowing agent and optionally at least one additive selected from the group consisting of colorants, pigments such as carbon black, stabilizers, acid scavengers, antioxidants and mixtures thereof.

Article and use

The polypropylene composition of the present invention may be used for the production of articles, such as shaped articles, preferably injection molded articles. Furthermore, the polypropylene composition of the present invention can be used for producing foamed articles, such as foamed injection molded articles. Even more preferred is the use for the production of automotive articles, in particular automotive interior and exterior articles, such as instrument racks, front end modules, front walls, structural supports, bumpers, side trims, accessory boards, body panels, spoilers, dashboards, interior trims and the like. Preferably, the article is an automotive interior article.

Thus, another aspect of the present invention relates to injection moulded articles as well as foamed articles, preferably foamed injection moulded articles, comprising the polypropylene composition as defined herein.

As already described above, the polypropylene homopolymer (H-PP1) as defined herein advantageously reduces the stiffness reduction factor of the foamed injection molded article.

Thus, the present invention relates in another aspect to the use of a polypropylene homopolymer (H-PP1) for reducing the stiffness reduction factor of a foamed injection molded article, the stiffness reduction factor being determined by the difference in flexural modulus measured according to ISO 178 of the unfoamed and foamed injection molded article, and the stiffness reduction factor of the foamed injection molded article being reduced by at least 40 compared to an article comprising the same amount of polypropylene polymerized in the presence of a ziegler-natta catalyst, wherein the polypropylene homopolymer (H-PP1) has

i) A melting temperature Tm measured by Differential Scanning Calorimetry (DSC) in the range of 150 to 160 ℃,

ii) in the range of 0.50 to 1.00 mol% of a monomer mixture of¹³The content of 2,1 erythro-type domain defects as determined by C-NMR spectroscopy,

iii) at least 97.5% of¹³Isotactic triad fraction (mm) determined by C-NMR spectroscopy, and

iv) a xylene cold soluble fraction (XCS) determined according ISO 16152 at 23 ℃ equal to or lower than 1.5 wt. -%.

With regard to the polypropylene homopolymer (H-PP1) and preferred embodiments thereof, reference is made to the statements provided above when discussing in more detail the polypropylene homopolymer (H-PP1) present in the polypropylene composition.

The present invention will now be described in further detail by the embodiments provided below.

Examples

1. Defining/measuring method

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

MFR₂(230 ℃) in accordance with ISO 1133(230 ℃, 2.16kg load).

Xylene cold soluble (XCS, wt%) according to ISO 16152; a first edition; 2005-07-01 was measured at 25 ℃.

The intrinsic viscosity is measured in accordance with DIN ISO 1628/1, 10 months 1999 (in decalin, at 135 ℃).

Quantification of microstructures by NMR spectroscopy

The comonomer content of the polymer was quantified using quantitative Nuclear Magnetic Resonance (NMR) spectroscopy. Use to¹H and¹³c Bruker Advance III 400NMR spectrometers operating at 400.15 and 100.62MHz respectively record quantitative measurements in solution¹³C{¹H } NMR spectrum. Use of¹³C-optimized 10mm extended temperature probe all spectra were recorded at 125 ℃, using nitrogen for all pneumatic devices. About 200mg of material was mixed with chromium (III) acetylacetonate (Cr (acac)₃) Dissolved together in 3ml of 1, 2-tetrachloroethane-d₂(TCE-d₂) A 65mM relaxant solution in solvent was obtained (Singh, g., Kothari, a., Gupta, v., Polymer Testing 285 (2009), 475). To ensure the solution is homogeneous, after initial sample preparation in the heating block, 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 setting is chosen primarily for high resolution and is quantitatively needed due to the accurate quantification of ethylene content. Using standard single pulse excitation without NOE, optimized tip angle (tip angle), 1s cycle delay and dual stage WALTZ16 decoupling schemes (Zhou, z., Kuemmerle, r., Qiu, x., redwire, d., Cong, r., Taha, a., Baugh, d.winnford, b., j.mag.reson.187(2007) 225; Busico, v., Carbonniere, p., Cipullo, r., pellechi, r., sevelchi, Severn, j., Talarico, g., macromol.rapid comm.2007, 28,1128) were used. A total of 6144(6k) transients were obtained for each spectrum.

Quantification using proprietary computer programs¹³C{¹H NMR spectra were processed, integrated and relevant quantitative properties were determined from the integrations. All chemical shifts are indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00ppm using a solvent's chemical shift. Even if this building block is not present, the method can be comparable referenced. Characteristic signals corresponding to ethylene incorporation were observed (Cheng, h.n., Macromolecules 17(1984), 1950).

In case a characteristic signature corresponding to a 2,1 erythro-type regional defect is observed (as described in l.resconi, l.cavalo, a.fat, f.Piemontesi, chem.Rev.2000,100(4),1253, Cheng, H.N., Macromolecules 1984,17,1950 and W-J.Wang and S.Zhu, Macromolecules 2000,331157), the effect of the regional defect on the determined property needs to be corrected. No characteristic signals corresponding to other types of area defects were observed.

By pairing Macromolecules 33(2000),1157) using the method of Wang et al (Wang, W-J., Zhu, S., Macromolecules 33, 1157)¹³C{¹H } multiple signals over the entire spectral region of the spectrum are integrated to quantify the comonomer fraction. This method was chosen for its robustness and ability to account for the presence of regional defects when needed. The integration region is slightly adjusted to improve the encounterTo the whole range of comonomer contents.

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

E＝0.5(Sββ+Sβγ+Sβδ+0.5(Sαβ+Sαγ))

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

E＝0.5(I_H+I_G+0.5(I_C+I_D))

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

The mole percentage of comonomer incorporation was calculated from the mole fraction:

e [ mol% ] -100 fE

The weight percentage of comonomer incorporation was calculated from the mole fraction:

e [ wt% ] ═ 100 (fE × 28.06)/((fE × 28.06) + ((1-fE) × 42.08))

Comonomer sequence distribution at the triad level 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 robustness and the integration region was slightly adjusted to improve applicability to a wider range of comonomer contents.

Flexural modulus was determined on an injection molded specimen of 80X 10X 4mm prepared according to ISO 294-1:1996 at 3-point bending according to ISO 178.

DSC analysis, melting temperature (T)_m) Crystallization temperature (T)_c) Heat of fusion (H)_m) And heat of crystallization (H)_c): measurements were made on 5 to 7mg samples using a TA Instrument Q2000 Differential Scanning Calorimeter (DSC). DSC in accordance with ISO 11357/part 3/method C2 at-30 to +225 ℃ with a scan rate of 10 ℃/min in the heat/cool/heat cycleIs operated in the temperature range of (1). Crystallization temperature (T)_c) And heat of crystallization (H)_c) Measured by a cooling step, and a melting temperature (T)_m) And heat of fusion (H)_m) As determined by the second heating step.

The glass transition temperature Tg and the storage modulus G' were determined by dynamic mechanical analysis (DMTA) according to ISO 6721-7. The measurements were carried out in the distortion mode on compression-molded specimens (40X 10X 1mm3) at a heating rate of 2 ℃/min and a frequency of 1Hz between-100 ℃ and +150 ℃. When determining Tg from a curve of loss angle (tan (δ)), the storage modulus (G ') curve is used to determine the temperature of G' at 40MPa, which represents a measure for the heat distortion resistance.

The piercing energy and the energy to maximum force were determined according to ISO 6603-2 during the instrumented drop hammer impact test on plates of dimensions 148X 2 mm. The test was carried out at room temperature with a lubricating hammer head having a diameter of 20mm and an impact speed of 10 mm/s.

Number average molecular weight (M)_n) And weight average molecular weight (M)_w) Determined by Gel Permeation Chromatography (GPC) according to ISO 16014-4:2003 and ASTM D6474-99. A polymerChar GPC instrument equipped with an Infrared (IR) detector was used at 160 ℃ and a constant flow rate of 1mL/min, using a 3X Olexis and 1X Olexis guard column from Polymer Laboratories and 1,2, 4-trichlorobenzene (TCB, stabilized with 250 mg/L2, 6-di-tert-butyl-4-methylphenol) as the solvent. 200 μ L of sample solution was injected for each assay. The column set was calibrated using a universal calibration (according to ISO 16014-2:2003) with at least 15 narrow MWD Polystyrene (PS) standards in the range of 0.5kg/mol to 11500 kg/mol. The Mark Houwink constants for the PS, PE and PP used were as described in accordance with ASTM D6474-99. All samples were prepared by dissolving 5.0 to 9.0mg of polymer in 8mL (same as the mobile phase) of stable TCB at 160 ℃ for 2.5 hours for PP and 3 hours for PE under continuous mild shaking in the automatic feeder of the GPC instrument at maximum 160 ℃.

Particle size d₅₀And top cut d₉₅Particle size distribution [ mass percent ] determined by gravitational liquid sedimentation according to ISO 13317-3(Sedigraph)]And (4) calculating.

The cell structure of the foamed part was determined from the cross section of the foamed injection-molded plate by means of an optical microscope.

Total carbon emissions were determined from the granules according to VDA 277: 1995.

Volatile Organic Content (VOC) was measured according to VDA 278, year 2011, month 10.

2. Examples of the embodiments

Synthesis of metallocene:

the metallocene (rac-trans-dimethylsilylene (2-methyl-4-phenyl-5-methoxy-6-tert-butylindenyl) (2-methyl-4- (4-tert-butylphenyl) indenyl) zirconium dichloride) was synthesized as described in WO 2013/007650. Metallocene-containing catalysts were prepared using this metallocene and MAO catalyst system and trityl tetrakis (pentafluorophenyl) borate as catalyst 3 according to WO2015/11135, provided that the surfactant was 2,3,3, 3-tetrafluoro-2- (1,1,2,2,3,3, 3-heptafluoropropoxy) -1-propanol.

TABLE 1 polymerization Process conditions and Properties of Polypropylene homopolymer H-PP1

B1 prepolymerization reactor
		Temperature (. degree.C.)	20
Pressure (kPa)	5238
		B2 Loop reactor
Temperature (. degree.C.)	70
		Pressure (kPa)	5292
H2/C3 ratio (mol/kmol)	0.42
		Polymer split ratio (% by weight)	49.0
MFR2(g/10min)	91.0
		XCS(％)	1.4
B3 gas phase reactor
		Temperature (. degree.C.)	80
Pressure (kPa)	2406
		H2/C3 ratio (mol/kmol)	3.2
Polymer split ratio (% by weight)	51.0
		MFR2(g/10min)	71.0
XCS(％)	1.3

The polypropylene compositions were prepared by mixing in a co-rotating twin screw extruder from Coperion ZSK18 with a typical screw configuration and a melt temperature in the range of 200 to 220 ℃. The molten strand was solidified in a water bath and then pelletized.

Table 2: general profiles of compositions used in the inventive examples and comparative examples IE1, IE2 and CE3

		IE1	IE2	CE1
					H-PP1	[ weight% ]]	96.5	47.5
PP2	[ weight% ]]		49	96.5
					Additive agent	[ weight% ]]	3.5	3.5	3.5

H-PP1 is Borealis AG with a melt flow Rate MFR of about 71g/10min₂(230 ℃) of an isotactic unimodal polypropylene homopolymer and prepared in the presence of a single-site catalyst as listed in table 1.

PP2 is Borealis AG with a melt flow Rate MFR of about 75g/10min₂(230 ℃), Tm of 164 ℃, density of 0.905g/cm3, and was prepared in the presence of a Ziegler-Natta catalyst.

The additives included 1.5% by weight of carbon black, 0.2% by weight of the nucleating agent Hyperform HPN-20E from Milliken & Company, 0.15% by weight of the antioxidant IrganoxB215FF from BASF AG, Germany, 0.15% by weight of calcium stearate and 1.5% by weight of a carrier material.

The mechanical characteristics of inventive examples IE1 and IE2 and comparative example CE1 are shown in table 3 below.

Table 3: characteristics of the Polypropylene (PP) composition prepared

From table 3 it can be concluded that the foamed sheet of IE1 has fine pores and a lower stiffness reduction factor, defined by the difference in stiffness of the compacted unfoamed and foamed parts, compared to comparative example CE 1. At similar Melt Flow Rates (MFR), IE1 also has a lower VOC/FOG than CE1, primarily due to the nature of the catalyst used to produce the polymer. IE can also be used as a modifier for CE 1. The embodiment other than IE1 (i.e., IE2) as compared to CE1 resulted in a lower stiffness reduction factor, improved emissions, and finer apertures.