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CN-122003462-A - Method for improving nucleation efficiency of SSC (single crystal clock) material

CN122003462ACN 122003462 ACN122003462 ACN 122003462ACN-122003462-A

Abstract

The present invention relates to a polypropylene composition comprising a single-site catalysed polypropylene homopolymer (SScPPH), having a melt flow rate MFR2 in the range of 1 to 500 g/10 min (under 230 ℃ and 2.16 kg load according to ISO 1133), a melting temperature Tm in the range of 149 to 160 ℃ (DSC according to ISO 11357), an amount of 2, 1-erythro region defects in the range of 0.10 to 1.20 mol% (as determined by 13C NMR spectroscopy), 0.01 to 1.00 wt% of a second dispersible particulate α -nucleating agent, and 0 to 500 ppm weight of a third dispersible particulate α -nucleating agent as a polymer nucleating agent.

Inventors

  • WANG JINGBO
  • Marcus Galettner
  • Klaus Bain Wright-tner
  • Anna Maria Hartl
  • Paulie Leskinin

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. A polypropylene composition comprising a single-site catalysed polypropylene homopolymer (SScPPH), having a melt flow rate MFR2 in the range of 1 to 500 g/10 min (under 230 ℃ and 2.16 kg load according to ISO 1133), a first dispersible particle α -nucleating agent in the range of 149 to 160 ℃ (DSC according to ISO 11357), a second dispersible particle α -nucleating agent in the range of 0.02 to 1.80 wt%, and a third dispersible particle α -nucleating agent as a polymer nucleating agent in the range of 0 to 500ppm by weight, preferably 0 to 300 ppm, e.g. 0 to 150 ppm, the single-site catalysed polypropylene homopolymer having a melt flow rate MFR2 in the range of 1 to 500 g/10 min (under 230 ℃ and 2.16 kg load according to ISO 1133), a melt temperature Tm in the range of 149 to 160 ℃ (DSC according to ISO 11357), and an amount of 2, 1-erythro region defects in the range of 0.10 to 1.20 mol% (as determined by 13 C spectrum.
  2. 2. The polypropylene composition according to claim 1, wherein the composition contains 90.00 wt% or more, preferably 91.00 wt% or more, more preferably 92.00 wt% or more, such as 93.00 wt% or more, 94.00 wt% or more, 95.00 wt% or more, 95.50 wt% or more, or 96.00 wt% or more, preferably in the range of 90.00 to 99.98 wt%, more preferably in the range of 92.00 to 99.90 wt%, such as in the range of 93.00 to 99.50 wt%, in the range of 94.00 to 99.00 wt%, in the range of 95.00 to 98.50 wt%, or SScPPH in the range of 96.00 to 98.00 wt%.
  3. 3. Polypropylene composition according to claim 1 or 2, wherein the first dispersible granule a-nucleating agent or the components forming the mixture of the first dispersible granule a-nucleating agents are selected from low molecular weight organic type nucleating agents.
  4. 4. A polypropylene composition according to any one of claims 1 to 3, wherein the first dispersible granule a-nucleating agent or the components forming the mixture of the first dispersible granule a-nucleating agent are selected from the group consisting of: (i) Monocarboxylates, such as sodium benzoate or aluminum bis (4-tert-butylbenzoate), (Ii) Dicarboxylic or polycarboxylic acid salts, e.g. disodium salt of bicyclo (2.2.1) heptane-2, 3-dicarboxylic acid or calcium salt of 1, 2-cyclohexanedicarboxylic acid, and (Iii) Salts of phosphoric acid diesters, for example sodium 2,2 '-methylenebis (4, 6-di-tert-butylphenyl) phosphate or aluminum hydroxy bis [2,2' -methylenebis (4, 6-di-tert-butylphenyl) phosphate ]; in particular at least one of sodium benzoate, sodium 2,2' -methylenebis- (4, 6-di-tert-butyl-phenyl) -phosphate, hydroxy bis- (2, 4,8, 10-tetra-tert-butyl-6-hydroxy-12 h-dibenzo- (d, g) (1, 3, 2) -dioxaphosph-eight epoxide) -aluminum.
  5. 5. The polypropylene composition according to any one of claims 1 to 4, wherein the first dispersible granule α -nucleating agent or the components forming the mixture of the first dispersible granule α -nucleating agent is selected from the group consisting of aromatic carboxylates, preferably substituted or unsubstituted benzoates, more preferably benzoates having an alkyl substituent in the 4-position.
  6. 6. The polypropylene composition according to any one of claims 1 to 5, wherein the composition has (A) A melt flow rate MFR2 in the range of 1 to 500 g/10 min, preferably in the range of 10 to 500 g/10 min, more preferably in the range of 50 to 450 g/10 min, for example in the range of 70 to 300 g/10 min, and/or (B) A crystallization temperature Tc (determined according to ISO 11357 on the basis of differential scanning calorimetry DSC) in the range from 120 to 135 ℃, preferably in the range from 123 to 133 ℃, and/or (C) Flexural modulus (according to ISO 178) in the range 1800 to 2500 MPa, preferably in the range 1820 to 2300 MPa, more preferably in the range 1830 to 2200 MPa, and/or (D) Heat distortion temperature (HDT; according to ISO 75B, low load, measured on 80x10x4 mm3 samples) in the range 105 to 130 ℃, more preferably in the range 108 to 128 ℃, for example in the range 109 to 126 ℃.
  7. 7. Polypropylene composition according to any one of claims 1 to 6, wherein the second dispersible particulate a-nucleating agent or the components forming the mixture of the second dispersible particulate a-nucleating agent are selected from inorganic type nucleating agents (mineral nucleating agents), preferably at least one selected from the group consisting of carbonates, silicates, aluminates or aluminosilicates.
  8. 8. The polypropylene composition according to any one of claims 1 to 7, wherein the second dispersible particulate a-nucleating agent or the mixture component forming the second dispersible particulate a-nucleating agent is selected from the group consisting of inorganic compounds including calcium carbonate, talc, wollastonite, mica and kaolin, preferably talc.
  9. 9. The polypropylene composition according to any one of claims 1 to 8, wherein the third dispersible granule a-nucleating agent is poly (vinylcyclohexane) or poly (vinylcyclopentane).
  10. 10. The polypropylene composition according to any one of claims 1 to 9, further comprising up to 5.00 wt%, preferably 0.01 to 5.00 wt%, such as 0.01 to 2.00 wt% of an additive, preferably selected from the group consisting of antioxidants, UV stabilizers, antistatic agents, acid scavengers and slip agents, based on the polypropylene composition.
  11. 11. The polypropylene composition according to any one of claims 1 to 10, wherein the SScPPH is bimodal SScPPH and/or multimodal SScPPH, wherein the bimodal/multimodal SScPPH preferably comprises or consists of a first PPH component (PPH-C1) and a second PPH component (PPH-C2), and/or bimodal SScPPH is prepared in a two-stage polymerization process employing a slurry-Gas Phase Reactor (GPR) cascade such that PPH-C1 is prepared in a slurry reactor, PPH-C2 is prepared in a GPR, and/or multimodal SScPPH is prepared in a multistage polymerization process employing a cascade of at least two slurry reactors and at least one Gas Phase Reactor (GPRs) or in a multistage polymerization process employing a cascade of at least one slurry reactor and at least two gas phase reactor.
  12. 12. The polypropylene composition according to any one of claims 1 to 11, wherein the SScPPH has (A) In the range from 10 to 500 g/10 min, preferably in the range from 50 to 450 g/10 min, for example in the range from 70 to 300 g/10 min, and/or melt flow rate MFR2 (B) A melting temperature Tm in the range of 150 to 158 ℃, preferably in the range of 151 to 157 ℃, and/or (C) An amount of 2, 1-erythro region defects in the range of 0.15 to 1.10 mol%, preferably in the range of 0.20 to 1.00 mol%, for example in the range of 0.25 to 0.90 mol%, and/or (D) Xylene cold solubles content (XCS, according to ISO 16152 at 25 ℃) in the range of 0.10 wt% to 1.50 wt%, preferably in the range of 0.15 to 1.20 wt%, more preferably in the range of 0.20 to 1.10 wt%, e.g. in the range of 0.25 to 1.00 wt%.
  13. 13. Molded product comprising 60 to 100 wt% of the polypropylene composition according to any one of claims 1 to 12, preferably comprising 65 to 99 wt%, more preferably 70 to 98 wt%,75 to 97 wt%, such as 80 to 95 wt% of the polypropylene composition.
  14. 14. Use of the polypropylene composition according to any one of claims 1 to 12 for the preparation of molded products such as packaging articles, automotive exterior parts, automotive interior parts or housings for electrical or electronic devices.
  15. 15. Use of the polypropylene composition according to any one of claims 1 to 12 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

Method for improving nucleation efficiency of SSC (single crystal clock) material Technical Field The present invention relates to a method for increasing the nucleation efficiency of single site catalyzed (SSc) polypropylene materials, and in particular to a composition having improved nucleation efficiency and comprising an SSc propylene homopolymer (SScPPH). The invention also relates to the use of the composition. Background Polypropylene is a thermoplastic material that is widely used for its desirable processability, chemical resistance, electrical properties and mechanical properties. Thermoplastic refers to a plastic that softens flow when exposed to sufficient heat but retains its cured state after cooling. Polypropylene can be used to make a variety of injection molded articles such as household goods, kitchen equipment, toys, medical devices, appliances, and extruded articles such as pipes for vehicles, buildings, and infrastructure. Long relaxation times are required for the long chain macromolecules to transition from a disordered state to an ordered crystalline state during solidification and crystallization of the polymer melt. The crystallization rate and crystallization temperature are typically low, which may result in the formation of large-sized spherulites and distinct interfaces between these spherulites. The distinct interfaces between different large-sized spherulites may lead to different internal stresses. Upon impact, cracks may form at the interface, which may further lead to fracture and failure of the cured polymer. When the nucleating agent is added to the polypropylene melt, the nucleating agent provides sufficient nuclei. Thus, during cooling, the polypropylene melt may form smaller sized, ordered arrays, dense and uniformly dispersed spherulites or smaller units. Therefore, the generated internal stress is small and dispersed, so that the mechanical property and the thermal property of the polypropylene can be improved, and the successful application of the polypropylene is further promoted. In order to modify conventional polypropylene into functional materials with desirable physical properties (e.g., high stiffness, desirable impact resistance, and thermal stability), nucleation modification is one of the simplest and effective methods. The addition of the nucleating agent to the polypropylene can induce the polypropylene to form ordered arrangement and well-dispersed spherulites, thereby improving the physical properties of the polypropylene. For example, U.S. Pat. No. 9,085,683 B2 discloses a nucleating agent composition for improving the rigidity and toughness of polypropylene. WO 2014/202603 A1 discloses another nucleating composition. Disclosure of Invention It has surprisingly been found that a polypropylene homopolymer catalyzed at a specific unit point having a melt flow rate MFR 2 in the range of 1 to 500 g/10 min, a melting temperature Tm in the range of 149 to 160 ℃, and a 2, 1-erythro region defect amount in the range of 0.10 to 1.20 mol%, interacts with a combination of at least two dispersible particulate α -nucleating agents resulting in excellent nucleation efficiency. The present invention relates to a polypropylene composition comprising a single-site catalysed polypropylene homopolymer (SScPPH), from 0.01 to 1.00 wt% of a first dispersible granular alpha-nucleating agent, from 0.01 to 2.00 wt% of a second dispersible granular alpha-nucleating agent and from 0 to 500 ppm% by weight of a third dispersible granular alpha-nucleating agent as a polymeric nucleating agent, the respective amounts being given relative to the total composition. The melt flow rate MFR2 of the single-site catalyzed polypropylene homopolymer (SScPPH) is in the range of 1 to 500 g/10 min (at 230 ℃ and 2.16 kg load according to ISO 1133), the melting temperature Tm is in the range of 149 to 160 ℃ (DSC according to ISO 11357) and the amount of 2, 1-erythro region defects (hereinafter sometimes abbreviated as "region defects") is in the range of 0.10 to 1.20 mol% (as determined by 13 C NMR spectroscopy). In particular, single-site catalyzed polypropylene homopolymers are a family of interesting materials with a wide range of potential applications. However, the inevitable presence of regio defects in the polymer chains of such SScPPH materials, which can interfere with crystallization, conventional nucleation modifications may not be sufficient to achieve the good nucleation performance of the present challenging SScPPH. In addition, single-site catalyzed polypropylene is characterized by a narrow molecular weight distribution, reducing the inherent level of self-nucleation. However, the present inventors have unexpectedly found that the combination of the nucleating agents of the present invention can significantly improve the nucleation efficiency, and thus completed the present invention. The first, second and third nucleating agents are different from each other. The first, second