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CN-122003464-A - Dual nucleation for high flow impact copolymers

CN122003464ACN 122003464 ACN122003464 ACN 122003464ACN-122003464-A

Abstract

The present invention relates to a high-flowability ethylene-propylene copolymer composition having an improved balance of properties in terms of mechanical properties and impact properties. The ethylene-propylene copolymer composition has a melt flow rate MFR greater than 10 g/10 min and contains (A) 97.00 to 99.45. 99.45 wt% of an ethylene-propylene impact copolymer, (B) 0.05 to 0.50 wt% of an alpha-nucleating agent of formula (I) of the specification and (C) 0.50 to 2.00 wt% of a mineral alpha-nucleating agent, wherein the median particle size is 10 μm or less. The impact copolymer comprises a 1) 75-88 wt% crystalline polypropylene homopolymer portion (CF) having an intrinsic viscosity in the range of 0.7 to 2.6 dl/g, and a 2) 12-25-wt% amorphous ethylene-propylene copolymer portion (SF) having an intrinsic viscosity in the range of 1.5 to 4.5 dl/g and an ethylene content in the range of 25.0 to 55.0 wt%.

Inventors

  • WANG JINGBO
  • Marcus Galettner
  • Yanosh Morna

Assignees

  • 北欧化工有限责任公司

Dates

Publication Date
20260508
Application Date
20241004
Priority Date
20231011

Claims (15)

  1. 1. An ethylene-propylene copolymer composition comprising: a) 97.00 to 99.45 wt% of an ethylene-propylene impact copolymer comprising: a1 75-88 wt%, preferably 77-86 wt%, e.g. 79-85 wt% of crystalline polypropylene homopolymer fraction (CF, determined by CRYSTEX QC analysis) relative to 100 wt% of ethylene-propylene impact copolymer, having an intrinsic viscosity IV CF (measured in decalin at 135 ℃ according to ISO 1628/1) in the range of 0.7 to 2.6 dl/g, preferably 0.8 to 2.5 dl/g, e.g. 0.9 to 2.3 dl/g, and A2 12-25 wt%, preferably 14-23 wt%, for example 15-21 wt% of the amorphous ethylene-propylene copolymer fraction (SF, determined by CRYSTEX QC analysis), having an intrinsic viscosity IV SF (measured in decalin at 135C according to ISO 1628/1) in the range of 1.5 to 4.5 dl/g, preferably in the range of 1.7 to 4.0 dl/g, for example in the range of 1.9 to 3.5 dl/g, an ethylene content C2 SF (determined by FT-IR spectroscopy calibrated by quantitative 13 C-NMR spectroscopy) in the range of 25.0 to 55.0 wt%, preferably in the range of 30.0 to 50.0 wt%, for example in the range of 33.0 to 47.0 wt%, B) 0.05-0.50 wt%, preferably 0.08-0.40 wt% of an alpha-nucleating agent selected from the group consisting of salts of the following formula (I): Ra n M m X o (I) Wherein M is independently a metal cation, X is independently an anion, and Ra is independently an organic anion of formula (II): Formula (II) Wherein R is independently an aliphatic hydrocarbon group, k is independently in the range of 1 to 3, n is in the range of 1 to 4, m is 1 or 2, and o is selected such that the total charge of the salt of formula (I) is 0, and C) 0.50-2.00 wt%, preferably 0.55-1.95. wt%, of a mineral alpha nucleating agent, wherein the median particle size D50 (according to ISO 13317-3, sedigraph method) is less than 10 μm, preferably in the range from 0.5 to 10.0 μm, more preferably from 1.0 to 9.5 μm, for example from 1.5 to 9.0 μm, from 2.0 to 8.5 μm or from 2.2 to 8.0 μm, The MFR of the composition (at 230 ℃ C. And 2.16 kg load according to ISO 1133) is greater than 10 g/10 min, preferably 11-100 g/10 min, for example 12-90 g/10 min.
  2. 2. The ethylene-propylene copolymer composition of claim 1, wherein the mineral alpha-nucleating agent is talc.
  3. 3. The ethylene-propylene copolymer composition according to claim 1 or 2, wherein the ethylene-propylene impact copolymer has a total C2 content in the range of 4.2 to 11.2 wt%, preferably in the range of 5.0 to 10.5 wt%, such as in the range of 5.5 to 10.0 wt%, as determined by FT-IR spectroscopy calibrated by quantitative 13 C-NMR spectroscopy.
  4. 4. The ethylene-propylene copolymer composition of any one of claims 1 to 3, wherein the ethylene-propylene impact copolymer has a melting temperature Tm (determined according to ISO 11357, based on differential scanning calorimetry DSC) in the range of 160 to 170 ℃, preferably in the range of 162 to 168 ℃.
  5. 5. The ethylene-propylene copolymer composition according to any one of claims 1 to 4, wherein the crystalline polypropylene homopolymer fraction (CF) has an ethylene content C2 CF in the range of 0.3 to 2.5 wt%, preferably in the range of 0.5 to 2.2 wt%, such as in the range of 0.7 to 2.0 wt%.
  6. 6. The ethylene-propylene copolymer composition of any one of claims 1 to 5, wherein the ethylene-propylene impact copolymer has an intrinsic viscosity IV EP in the range of 0.8 to 3.0 dl/g, preferably in the range of 1.0 to 2.8 dl/g, such as in the range of 1.2 to 2.6 dl/g.
  7. 7. The ethylene-propylene copolymer composition according to any one of claims 1 to 6, wherein the ratio (IV SF /IV CF ) of the intrinsic viscosity of the amorphous ethylene-propylene copolymer fraction (SF) to the intrinsic viscosity of the crystalline polypropylene homopolymer fraction (CF) is in the range of 0.9 to 3.5, preferably in the range of 1.0 to 3.0, for example in the range of 1.1 to 2.8.
  8. 8. The ethylene-propylene copolymer composition according to any one of claims 1 to 7, wherein the composition has a crystallization temperature Tc (determined according to ISO 11357 based on differential scanning calorimetry DSC) in the range of 125 to 135 ℃, preferably in the range of 128 to 132 ℃.
  9. 9. The ethylene-propylene copolymer composition according to any one of claims 1 to 8, wherein the composition has one or more, preferably all, of the following properties: i flexural modulus (according to ISO 178) in the range 1400 to 1750 Mpa, preferably in the range 1450 to 1700 MPa, Ii5.5 kJ/m 2 or higher, preferably in the range from 6.0 to 15.0 kJ/m 2 , for example NIS23 (Charpy notched impact strength, according to ISO 179 1eA at 23 ℃) in the range from 6.5 to 12.5 kJ/m 2 , Iii2.5 kJ/m 2 or higher, preferably in the range of 2.8 to 7.0 kJ/m 2 , for example NIS-20℃in the range of 2.9 to 6.5 kJ/m 2 (Charpy notched impact strength, 1eA at-20℃according to ISO 179), Iv) a heat distortion temperature (HDT; according to ISO 75B, low load, measured on 80X10X 4mm 3 samples) in the range from 95 to 115 ℃, preferably in the range from 97 to 112 ℃, for example in the range from 98 to 110 ℃, V1.75% or less, preferably in the range of 0.90% to 1.70% (MD shrinkage; measured as defined in the specification), Vi9900 or more, preferably in the range 10000 to 16000, defined as the product of NIS23 (Charpy notched impact strength, at 23 ℃ according to ISO 179 1 eA) [ kJ/m 2 ] and flexural modulus (according to ISO 178) [ MPa ], Vii) a mechanical property parameter MPP2 in the range 6500 to 12000, preferably in the range 6700 to 10000, defined as the product of NIS23[ kJ/m 2 ] and flexural modulus [ MPa ] divided by MD shrinkage (machine direction shrinkage; measured as defined in the specification) [% ], Viii a xylene cold soluble content (XCS, according to ISO 16152 at 25 ℃) in the range of 12 to 30 wt%, preferably in the range of 14 to 25 wt%, for example in the range of 15 to 22 wt%, Ix is in the range of 30 to 50 wt%, preferably in the range of 32 to 47 wt%, for example in the range of 35 to 45 wt%, of C2 content C2-XCS in the xylene cold soluble fraction, as determined by quantitative 13 C-NMR spectroscopically calibrated FT-IR spectroscopy, X is in the range from 0.8 to 3.0 dl/g, preferably in the range from 1.0 to 2.8 dl/g, for example an intrinsic viscosity IV EP in the range from 1.2 to 2.6 dl/g.
  10. 10. The ethylene-propylene copolymer composition according to any one of claims 1 to 9, wherein in formula (I), M is independently an alkali metal cation, an alkaline earth metal cation, a boron cation or an aluminum cation, preferably an alkali metal cation or an aluminum cation.
  11. 11. The ethylene-propylene copolymer composition according to any one of claims 1 to 10, wherein in formulae (I) and (II), m is 1 or 2, preferably 1, o is 0, 1 or 2, preferably 0 or 1, x is independently an inorganic anion, preferably a monovalent inorganic anion, more preferably selected from the group consisting of Cl - 、OH - 、SH - 、HSO 3 - 、HSO 4 - 、NO 3 - 、NO 2 - 、SO 4 2- 、PO 4 3- 、CO 3 2- or CN - or less, preferably OH - 、SH - or NO 3 - , more preferably OH - , R is independently an aliphatic hydrocarbon group having 1 to 8 carbon atoms, preferably 2 to 6 carbon atoms, more preferably 4 to 5 carbon atoms, more preferably an acyclic (open chain) aliphatic hydrocarbon group, even more preferably a linear or branched alkyl group, more preferably a branched alkyl group, more preferably selected from the group consisting of isopropyl, isobutyl, sec-butyl, tert-butyl and neopentyl, preferably tert-butyl, k is 1 or 2, preferably 1, n is 1 or 2 or 3, preferably 1 or 2, more preferably 2.
  12. 12. The ethylene-propylene copolymer composition according to any one of claims 1 to 11, further comprising up to 2.45 wt%, preferably 0.01 to 2.45 wt%, of an additive, preferably selected from the group consisting of antioxidants, UV stabilizers, antistatic agents, acid scavengers and slip agents.
  13. 13. The ethylene-propylene copolymer composition according to any one of claims 1 to 12 produced by a process comprising the steps of: a) Polymerizing propylene in a first polymerization reactor in the presence of a ziegler-natta catalyst system to produce a first propylene polymer fraction; b) Transferring a polymerization mixture comprising a ziegler-natta catalyst system and a first propylene polymer portion from a first polymerization reactor to a second polymerization reactor; c) Polymerizing propylene in a second polymerization reactor in the presence of a ziegler-natta catalyst system to produce a second propylene polymer fraction; d) Transferring the polymerization mixture comprising the ziegler-natta catalyst system and the first and second propylene polymer portions from the second polymerization reactor to a third polymerization reactor; e) Polymerizing propylene and ethylene in the presence of a ziegler-natta catalyst system in a third polymerization reactor to produce a propylene-ethylene copolymer fraction; f) Withdrawing from the third polymerization reactor a polymerization mixture comprising a Ziegler-Natta catalyst system, a first and a second propylene polymer fraction and a third propylene-ethylene copolymer fraction, and G) Obtaining a polymer composition comprising a first and a second propylene polymer fraction and a third propylene-ethylene copolymer fraction, The process optionally is preceded by a prepolymerization step.
  14. 14. Molded product comprising 50 to 100 wt% of the ethylene-propylene copolymer composition according to any one of claims 1 to 13, preferably comprising 60 to 100 wt%, more preferably 70 to 100 wt%, such as 80 to 100 wt%, 90 to 100 wt%, 95 to 100 wt%, 98 to 100 wt% or 98 to 99 wt% of the ethylene-propylene copolymer composition.
  15. 15. Use of the ethylene-propylene copolymer composition according to any one of claims 1 to 13 for the preparation of molded products, such as packaging articles, automobile exterior parts, automobile interior parts or electrical or electronic equipment housings, and/or for the preparation of injection molded articles, preferably thin-walled packaging articles, such as cups, trays, pails or lids, having an average wall thickness of 2 mm or less.

Description

Dual nucleation for high flow impact copolymers Technical Field The present invention relates to a high-flowability ethylene-propylene copolymer composition having an improved balance of properties in terms of mechanical properties and impact properties. The invention also relates to the use of the composition. Background Heterophasic ethylene-propylene copolymers (also known as ethylene-propylene impact copolymers, or abbreviated as heterophasic copolymers HECO) are widely used in the packaging industry due to their excellent combination of stiffness and impact properties. One can find application in many aspects of daily life. One of the main fields of application of such copolymers is the injection molding of thin-walled articles. Typical examples include plastic cups, pails and small containers primarily for food and non-food packaging. In order to be suitable for thin wall injection molding applications, polypropylene should exhibit excellent processability/flowability, typically reflected by a high Melt Flow Rate (MFR), i.e. a low average molecular weight. Nevertheless, in the polymer and packaging industry, it is still desirable to improve the obtainable heterophasic copolymer compositions with high Melt Flow Rate (MFR) in view of the mechanical properties, in particular the amount of impurities. However, the prior art has several limitations. Accordingly, there is a need in the art for ethylene-propylene copolymer compositions having a high melt flow rate MFR of greater than 10 g/10 min suitable for injection molding and thin-walled article production, which exhibit an improved balance of properties, such as high flexural modulus and impact strength, high processability, such as high melt flow rate, in terms of mechanical properties and impact resistance. Disclosure of Invention It has surprisingly been found that the interaction of a specific ethylene-propylene impact copolymer having 75-88 wt% Crystalline Fraction (CF) and 12-25 wt% amorphous fraction (SF, sometimes also referred to as soluble fraction) with a combination of two specific alpha-nucleating agents results in an excellent balance between mechanical properties, impact properties and processability. The present invention relates to an ethylene-propylene copolymer composition comprising 97.00 to 99.45wt% (relative to 100% of the ethylene-propylene copolymer composition) of an ethylene-propylene impact copolymer comprising 75 to 88 wt% of a crystalline polypropylene homopolymer fraction (CF) and 12 to 25% wt% of an amorphous ethylene-propylene copolymer fraction (SF), both determined according to CRYSTEX QC analysis, 0.05 to 0.50 wt% of an alpha-nucleating agent selected from the group consisting of salts of the following formula (I), and 0.50 to 2.00 wt% of a mineral alpha-nucleating agent, wherein the median particle diameter (D50, measured according to ISO 13317-3 sedimentation) is 10 μm or less. The melt flow rate (MFR 2 at 230 ℃ and a load of 2.16kg according to ISO 1133) of the composition is greater than 10 g/10 min. The intrinsic viscosity IV CF of the Crystalline Fraction (CF) (measured in decalin at 135 ℃ C. According to ISO 1628/1) is in the range from 0.7 to 2.6 dl/g. The intrinsic viscosity IV SF of the amorphous fraction (SF) (measured in decalin at 135℃according to ISO 1628/1) is in the range 1.5 to 4.5 dl/g and the ethylene content C2 SF (determined by quantitative 13 C-NMR spectroscopy calibrated FT-IR spectroscopy) is in the range 25.0 to 55.0 wt%. Formula (I): Ran Mm Xo in formula (I), M is independently a metal cation, X is independently an anion, ra is independently an organic anion of formula (II): formula (II) In formula (II), R is independently an aliphatic hydrocarbon group, k is independently in the range of 1 to 3, n is in the range of 1 to 4, m is 1 or 2, and o is selected such that the total charge of the salt of formula (I) is 0. The inventors have unexpectedly found that the synergistic interaction of two specific alpha nucleating agents as defined above with a specific impact copolymer as defined above results in excellent properties, in particular in an advantageous balance between processability, mechanical properties and impact properties. Furthermore, the invention relates to molded articles comprising the composition according to the invention, and to the use of the composition according to the invention for producing molded articles. Definition of the definition Unless otherwise indicated, the following amounts are expressed in weight percent (wt.). The term "comprising" (and the term "comprising") as used herein does not exclude other components. For the purposes of the present invention, the term "consisting of" is considered to be the term "comprising" (and the terms "containing", "including" or "having") unless otherwise expressly defined. Likewise, if a group is defined hereinafter to include at least a certain number of embodiments, this should also be understood as disclosing a group, which pre