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KR-20260066161-A - Polyolefin composition

KR20260066161AKR 20260066161 AKR20260066161 AKR 20260066161AKR-20260066161-A

Abstract

a) 70 to 99 weight% of a polyethylene polymer (A) which is a copolymer of one or more C3- C12 α-olefins having an MFR of 0.1 to 5.0 g/ 10 min (190°C/2.16 kg, ISO 1133), a melting point Tm of less than 100°C (DSC, ISO 11357/3), and a density of 865 to 905 kg/m³ (ASTM D792); and b) 1 to 30 wt% of high-density polyethylene wax (B) having an MFR greater than 300 g/10 min (ISO1133, 190°C/2.16 kg) and/or a weight average molecular weight of 1,000 to 35,000 and a Tm (DSC, ISO 11357/3) in the range of 120 to 135°C. A polyolefin composition comprising

Inventors

  • 카르멜리 엔리코
  • 왕 징보
  • 가흐라이트너 마르쿠스

Assignees

  • 보레알리스 게엠베하

Dates

Publication Date
20260512
Application Date
20240919
Priority Date
20230919

Claims (17)

  1. a) 70 to 99 weight% of polyethylene polymer (A), wherein the polyethylene polymer (A) is a copolymer of ethylene and one or more C3 - C12 α-olefins and has a melt flow rate (MFR) of 0.1 to 5.0 g/10 min (190°C/2.16 kg, ISO 1133), a melting point Tm of less than 100°C (DSC, ISO 11357/3), and a density of 865 to 905 kg/ m³ (ASTM D792); and b) high-density polyethylene wax (B) having 1 to 30 wt%, an MFR greater than 300 g/10 min (ISO1133, 190°C/2.16 kg) and/or a weight average molecular weight (GPC) of 1,000 to 35,000 and a Tm in the range of 120 to 135°C (DSC, ISO 11357/3) A polyolefin composition comprising
  2. A polyolefin composition according to claim 1, wherein the polyethylene polymer (A) is present in an amount of 75 to 98 weight%, preferably 85 to 97 weight%, based on the total weight of the entire composition, and/or the wax is present in an amount of 2 to 25 weight%, preferably 3 to 15 weight%, based on the total weight of the entire composition.
  3. A polyolefin composition according to claim 1 or 2, wherein the polyethylene polymer (A) has a density in the range of 865 to 904 kg/ m³ , preferably 865 to 903 kg/ m³ .
  4. A polyolefin composition according to any one of claims 1 to 3, wherein the polyethylene polymer (A) has a melt flow rate (MFR) of 0.5 to 2.0 g/10 min at 190°C/2.16 kg.
  5. A polyolefin composition according to any one of claims 1 to 4, wherein the polyethylene polymer (A) is a polyethylene plastom.
  6. A polyolefin composition according to any one of claims 1 to 5, wherein the wax has a melt flow rate (MFR) of at least 400 g/10 min, preferably at least 450 g/10 min, more preferably at least 490 g/10 min at 190°C/2.16 kg and/or a weight average molecular weight of 3,000 to 25,000.
  7. A polyolefin composition according to any one of claims 1 to 6, wherein the wax is a homopolymer.
  8. A polyolefin composition according to any one of claims 1 to 7, wherein the wax is manufactured using a metallocene catalyst.
  9. A polyolefin composition according to any one of claims 1 to 8, wherein the wax has a density of 950 to 990 kg/ m³ , e.g., at least 960 kg/ m³ .
  10. A polyolefin composition according to any one of claims 1 to 9, wherein the polyethylene polymer (A) and the wax are the only polymer components in the composition.
  11. In any one of paragraphs 1 through 10, The storage modulus E' (23°C) of the above polyolefin composition increases by 2.0 to 4.0 times compared to the neat polymer (A); and/or The solidification temperature (Tc(Rheo)) determined by dynamic rheology is at least 12°C higher than the solidification temperature of the knit polymer (A) in the case of the polyolefin composition; and/or The softening temperature Tsoft is increased by 10 to 30°C in the case of the polyolefin composition compared to the knit polymer (A), Polyolefin composition.
  12. A polyolefin composition according to any one of claims 1 to 11, wherein the polyethylene polymer (A) has an ethylene content of 60 to 95 weight%, preferably 65 to 90 weight%, and more preferably 70 to 88 weight%.
  13. For use in improving the film processability of a polyethylene polymer (A), a high-density polyethylene wax (B) having an MFR (190°C/2.16 kg) greater than 300 g/10 min and/or a weight average molecular weight of 1,000 to 35,000 and a Tm in the range of 120 to 135°C, The above polyethylene polymer is a copolymer of ethylene and one or more C3 -C12 α-olefins, having an MFR of 0.1 to 5.0 g/10 min (190°C/2.16 kg), a melting point Tm of less than 100°C, and a density of 865 to 905 kg/ m³ .
  14. For use in improving the pelletization of a polyethylene polymer (A) of a high-density polyethylene wax (B) having an MFR (190°C/2.16 kg) greater than 300 g/10 min and/or a weight average molecular weight of 1,000 to 35,000 and a Tm in the range of 120 to 135°C, The above polyethylene polymer is a copolymer of ethylene and one or more C3 -C12 α-olefins, having an MFR of 0.1 to 5.0 g/10 min (190°C/2.16 kg), a melting point Tm of less than 100°C, and a density of 865 to 905 kg/ m³ .
  15. Use of a polyolefin composition as a hot melt adhesive as defined in any one of claims 1 to 12.
  16. A film comprising a polyolefin composition defined in any one of claims 1 to 12.
  17. A substrate that is at least partially coated with a hot melt adhesive, wherein the adhesive comprises a polyolefin composition defined in any one of claims 1 to 12.

Description

Polyolefin composition The present invention relates to a polyolefin composition, specifically a polyolefin composition comprising a polyethylene polymer which is a copolymer of ethylene and one or more C3 - C12 α-olefins and a high-density polyethylene wax. The composition is particularly useful as a film and a hot-melt adhesive. The present invention also relates to the use of high-density polyethylene wax to improve the film processability of the polyethylene polymer, the use of high-density polyethylene wax to improve the pelletization of the polyethylene polymer, the use of said polyolefin composition as a hot-melt adhesive, a film comprising said polyolefin composition, and a substrate at least partially coated with said polyolefin composition and a hot-melt adhesive comprising said polyolefin composition. Challenges exist in developing polyethylene polymers with a desirable balance of properties, for example, as films or hot-melt adhesives. Linear low-density polyethylene (LLDPE) and, in particular, polyethylene plastomers can cause problems during production and processing due to their low crystallinity and high ductility. Increasing the crystallization rate of polyethylene (PE) plastomers has been previously considered. One possibility for improving the situation is nucleation, but its value is limited because the problem lies in the crystal growth rate (G) (both are required for rapid crystallization) rather than the limited nucleation density (N). Blends of plastomers and high-density polyethylene (HDPE) are known to crystallize faster, but they essentially require a somewhat high concentration of HDPE (≥ 20 wt%), which also affects other properties of the base polymer. Such blends are described, for example, in the literature [Rana et al ., Journal of Applied Polymer Science, 1998, 69, 2441-2450], which reports results demonstrating a loss of ductility and flexibility with increasing HDPE content. Polymer film manufacturers seek films with excellent mechanical properties, such as high impact strength, puncture resistance, toughness, and stiffness. The polymers used to manufacture the films must also possess excellent processability. That is, bubbles formed during the extrusion process must be stable, and the extruded film must have a uniform film thickness distribution. Unfortunately, the challenge facing those in the art is that it seems inevitable that improving one characteristic will adversely affect another. For example, low-density polyethylene (LDPE) produces films with excellent optical properties and can be processed at low temperatures and pressures while maintaining melt strength and excellent processability, but films made from LDPE contribute little to mechanical properties. Linear low-density polyethylene (znLLDPE) produced from conventional unimodal Ziegler-Natta has moderate mechanical properties but lacks notable processability, which implies poor bubble stability and extrusion pressure. Optical properties and puncture resistance were improved using metallocene linear low-density polyethylene, but this came at the expense of processability. These polymers are sensitive to film processing conditions and lack melt strength. Therefore, the problem faced by film manufacturers is that attempting to improve one characteristic tends to adversely affect another equally important characteristic. Various blends of these materials have been proposed in the industry to maximize film performance by combining the advantageous properties of specific polymers. Polyolefin films are often manufactured by extruding a polymer melt into a water bath in the form of a film through a suitable device, where the film is cooled and solidified. The film is then sent out of the water bath to undergo additional processing steps. However, when exiting the water bath, the film may carry water, which interferes with subsequent processing steps. EP 1506253 relates to a process for reducing this "moisture carry-over" using a polyolefin composition comprising at least one polyolefin wax. Hot melt adhesives (HMA) are used in many commercial fields, such as bookbinding, consumer and industrial packaging, diapers, furniture, and footwear. HMA is a thermoplastic polymer composition placed between two substrates in a molten state. Upon cooling, HMA solidifies and crystallizes to form a bond between the substrates. Ideally, HMA should provide excellent adhesion over a wide temperature range. It is also desirable for HMA to have a short set time. Set time is typically defined as the time it takes for the adhesive to solidify sufficiently to provide a bond strength between the substrates that is strong enough to prevent separation when the compressive force applied in the first stage of a packaging production line is removed. Key factors affecting set time are the crystallization rate of the adhesive, or the crystallization rate of one or more crystallizable components of the adhesive. Generally, a reduction in set time m