HETEROPHASE POLYPROPYLENE COMPOSITION WITH HIGH MELTING POINT

Claims

1. A heterophasic polypropylene composition containing a propylene copolymer matrix (A) of propylene with ethylene and 1-butene comonomer units and a propylene-ethylene elastomer (B) dispersed in the matrix, wherein the heterophasic polypropylene composition contains from 25 to 50 wt.%, based on the total weight of the heterophasic polypropylene composition and determined at 25°C according to ISO 16152, of a xylene-soluble fraction (XS) containing propylene comonomer units and, based on the total weight of the xylene-soluble fraction (XS), ethylene comonomer units at a content in the range of from 18.0 to 35.0 wt.%, and a xylene-soluble fraction (XS) having an intrinsic viscosity IV, determined according to ISO 1628-1 and 3, in the range of from 1.8 to 3.0 dl / g; and where the heterophasic polypropylene composition has, based on the total mass of the heterophasic polypropylene composition and determined using spectroscopy 13C-NMR, the content of 1-butene comonomer units in the range from 3.0 to 10.0 wt.%, and the content of ethylene comonomer units in the range from 5.0 to 15.0 wt.%, and where the heterophasic polypropylene has: i) melt flow index MFR2, determined according to ISO 1133 at 230°C, in the range from 0.1 to 20.0 g / 10 min, and ii) melting point T пл , determined using differential scanning calorimetry (DSC) described in the description, in the range from 157 to 170°C.

2. The heterophasic polypropylene composition according to claim 1, wherein the heterophasic polypropylene composition has a first glass transition temperature T ст1 , determined according to ISO 6721-7, in the range from -12 to 2°C and the second glass transition temperature T ст2 in the range from -55 to -35°C.

3. A heterophasic polypropylene composition according to any one of the preceding claims, wherein the heterophasic polypropylene composition has a flexural modulus, determined according to ISO 178, in the range from 300 to 700 MPa.

4. A heterophasic polypropylene composition according to any one of the preceding claims, wherein the heterophasic polypropylene composition has an impact strength at 23°C, determined according to ISO 179 / 1eA, in the range of 65.0 to 120.0 kJ / m 2 .

5. A heterophasic polypropylene composition according to any one of the preceding claims, wherein the heterophasic polypropylene composition has a crystallization temperature T кр , determined using differential scanning calorimetry (DSC) described in the description, in the range from 115 to 125°C for the non-nucleated heterophasic polypropylene composition and / or in the range from 121 to 135°C for the nucleated heterophasic polypropylene composition.

6. A heterophasic polypropylene composition according to any one of the preceding claims, wherein the heterophasic polypropylene composition is free of phthalate esters and their corresponding degradation products.

7. A heterophasic polypropylene composition according to any one of the preceding claims, wherein the propylene copolymer (A) is a multimodal propylene copolymer and / or the propylene-ethylene elastomer (B) is a unimodal propylene copolymer.

8. A heterophasic polypropylene composition according to any one of the preceding claims, wherein the heterophasic polypropylene composition comprises, based on the total weight of the heterophasic polypropylene composition, from 75 to 90 wt.% of a propylene copolymer (A) and from 10 to 25 wt.% of a propylene-ethylene elastomer (B).

9. A heterophasic polypropylene composition according to any one of the preceding claims, wherein the propylene copolymer (A) comprises two different fractions of propylene polymer: a) from 30 to 70% by weight, based on the total weight of the propylene copolymer (A), of a first fraction of propylene polymer (A1) which is a propylene homopolymer or a propylene copolymer of propylene with ethylene comonomer units, preferably which is a propylene homopolymer, and b) from 30 to 70 wt.%, based on the total weight of the propylene copolymer (A), of a second fraction of propylene polymer (A2), which is a propylene copolymer of propylene with ethylene comonomer units and 1-butene comonomer units.

10. A heterophasic polypropylene composition according to any one of the preceding claims, wherein the propylene copolymer (A) has, based on the total weight of the propylene copolymer (A) and determined by spectroscopy13 C-NMR, the content of 1-butene comonomer units in the range from 2.0 to 6.0 wt.% and the content of ethylene comonomer units in the range from 1.0 to 3.9 wt.%.

11. A method for producing a heterophasic polypropylene composition according to any one of the preceding paragraphs by a multi-stage method, including I) obtaining a first propylene polymer fraction (A1), which is a propylene homopolymer or a propylene copolymer of propylene with ethylene comonomer units, in a bulk phase reactor, preferably in a loop reactor, in a first polymerization stage in the presence of a Ziegler-Natta catalyst; II) moving the first propylene polymer fraction (A1) to a second polymerization stage and obtaining a second propylene polymer fraction (A2), which is a propylene copolymer of propylene with ethylene comonomer units and 1-butene comonomer units, in the presence of a Ziegler-Natta catalyst in a first gas-phase reactor (GPR1); and where the first propylene polymer fraction (A1) and the second propylene polymer fraction (A2) together form a propylene copolymer (A); and III) moving the propylene copolymer (A) to the third stage of polymerization and obtaining a propylene-ethylene elastomer (B) as a third fraction of the propylene polymer in the presence of a Ziegler-Natta catalyst in a second gas-phase reactor (GPR2) to obtain a heterophasic polypropylene composition.

12. The method according to claim 11, wherein the Ziegler-Natta catalyst comprises: a) compound(s) of a transition metal of groups 4-6 (IUPAC); b) a compound of a metal of group 2; c) an internal donor, wherein said internal donor is a non-phthalic compound, preferably a non-phthalic ester; d) a cocatalyst; and e) not necessarily an external donor.

13. The method according to claim 12, wherein the internal donor is preferably selected from (di)esters of non-phthalic carboxylic (di)acids, simple 1,3-diesters, their derivatives and mixtures thereof.

14. An article containing a heterophasic polypropylene composition according to any one of claims 1 to 10, preferably in the form of a film or a molded article.

15. Use of a heterophasic polypropylene composition according to any one of claims 1 to 10 in an article, preferably a film or a molded article.