EP-4735491-A1 - HIGH MELT STRENGTH POLYETHYLENE WITH AN ULTRA-HIGH MOLECULAR WEIGHT POLYETHYLENE COMPONENT

Abstract

Films include a polyethylene multimodal resin. The polyethylene multimodal resin includes the polymerized reaction product of ethylene and at least one alpha-olefin copolymer. The polyethylene multimodal resin includes a melt strength (MS) ≥ X 1 /I 2 + y, wherein X 1 is equal to 3.9, y is equal to 1.4, and I 2 is a melt index of the copolymer; MS is the melt strength in cN. The film includes a normalized dart strength (DS) greater than or equal to 9,876 minus 10,512 times the density of the polyethylene multimodal resin (DS ≥ 9,876 - 10,512 (ρ), wherein the normalized DS is measured in gram (g) according to ASTM 1709 Method A divided by the film thickness in mils.

Inventors

• FONTAINE, PHILIP P.
• HAMAD, Fawzi G.
• ROSEN, Mari S.

Assignees

• Dow Global Technologies LLC

Dates

Publication Date

20260506

Application Date

20240620

Claims (1)

1. 84689-WO-PCT/DOW 84689 WO CLAIMS 1. A film comprising a polyethylene multimodal resin, wherein: the polyethylene multimodal resin comprises the polymerized reaction product of ethylene and at least one alpha-olefin copolymer, and wherein the polyethylene multimodal resin comprises a melt strength (MS) ≥ X 1 /I 2 + y, wherein X 1 is equal to 3.9, y is equal to 1.4, and I2 is a melt index of the copolymer measured according to ASTM 1238 at 2.16 kg and 190 °C, and MS is the melt strength in cN (Rheotens device, 190°C, 2.4 mm/s 2 , 120 mm from the die exit to the center of the wheels, extrusion rate of 38.2 s -1 , capillary die of 30 mm length, 2 mm diameter and 180° entrance angle); and wherein the film comprises a normalized dart strength (DS) greater than or equal to 9,876 minus 10,512 times the density of the polyethylene multimodal resin (DS ≥ 9,876 - 10,512 (ρ), wherein the normalized DS is measured in gram (g) according to ASTM 1709 Method A divided by the film thickness in mils. 2. A film comprising a polyethylene multimodal resin, wherein: the polyethylene multimodal resin comprises the polymerized reaction product of ethylene and at least one alpha-olefin copolymer, and wherein the polyethylene multimodal resin comprises a melt strength (MS) ≥ x/I2 + y) wherein x is equal to 3.9, y is greater than or equal to 1.4, and I 2 is a melt index of the copolymer measured according to ASTM 1238 at 2.16 kg and 190 °C, and MS is the melt strength in cN (Rheotens device, 190°C, 2.4 mm/s 2 , 120 mm from the die exit to the center of the wheels, extrusion rate of 38.2 s -1 , capillary die of 30 mm length, 2 mm diameter and 180° entrance angle); and wherein the film comprises a normalized machine direction (MD) tear of greater than 190 gf/mil, wherein MD tear is measured according to ASTM D1922-15. 3. The film according to claim 1 or claim 2, wherein the film is a monolayer film. 4. The film according to any one of the preceding claims, wherein the film further comprises a layer of low density polyethylene resin having a density from 0.910 to 0.930 g/cc. 5. The film according to any one of the preceding claims, wherein the polyethylene multimodal resin comprises a density from 0.900 to 0.975 g/cc. 6. The film according to any one of the preceding claims, wherein the polyethylene multimodal resin comprises a density from 0.910 to 0.930 g/cc. 84689-WO-PCT/DOW 84689 WO 7. The film of any preceding claim, wherein the polyethylene multimodal resin has a density greater than or equal to 0.918 g/cc, a melt strength of at least 7 cN, and a melt flow ratio (I10/I2) greater than 5, and wherein the film has a dart strength of greater than 150 g/mil. 8. The film of any preceding claim, wherein the polyethylene multimodal resin has a density from 0.910 to 0.930 g/cc, a melt strength of at least 7 cN, and a melt flow ratio (I 10 /I 2 ) from 5 to 10, and wherein the film has dart strength of greater than 400 g/mil. 9. The film of any preceding claim, wherein the polyethylene multimodal resin has a melt strength of at least 7 cN, and the film has a machine direction tear of greater than 85 gf/mil as measured according to ASTM D1922-15. 10. The film of any preceding claim, wherein the polyethylene multimodal resin has a melt strength of at least 8 cN, and a rheology ratio V 0.1 /V 100 of less than or equal to 6, and wherein the film has a dart strength of greater than 800 g, wherein V 0.1 is the viscosity of the ethylene-based polymer at 190 °C at an angular frequency of 0.1 radians/second, and V100 is the viscosity of the ethylene-based polymer at 190 °C at an angular frequency of 100 radians/second. 11. The film of any one of the preceding claims, wherein the polyethylene multimodal resin has an overall density of from 0.918 to 0.925 g/cc or a melt strength greater than or equal to 6 cN.

Description

84689-WO-PCT/DOW 84689 WO HIGH MELT STRENGTH POLYETHYLENE WITH AN ULTRA-HIGH MOLECULAR WEIGHT POLYETHYLENE COMPONENT CROSS-REFERENCE TO RELATED APPLICATIONS [001] This application claims the benefit of U.S. Provisional Application Serial No. 63/510,774 filed June 28, 2023, the contents of which is incorporated in its entirety herein. TECHNICAL FIELD [002] Embodiments described in this disclosure generally relate to films having a high melt strength and, more specifically, relate to films produced from high melt strength polyethylene resins with an ultra-high molecular weight component. BACKGROUND [003] High melt strength is an advantageous property in polyethylene resins, as it improves the processability of the material. Low density polyethylene (LDPE), made via a radical process, typically exhibits high melt strength, but the LDPE resins generally have poor mechanical properties. In contrast, linear low-density polyethylene (LLDPE), made via solution or gas phase processes, typically has poor melt strength but excellent mechanical properties. To combat the issues surrounding LLDPE and LDPE, some amount of LDPE is typically blended into LLDPE in order to improve the processability of LLDPE resins. Unfortunately, the addition of LDPE leads to significant decreases in the mechanical properties of the resulting blends when compared with the superior performance of the LLDPE resin. SUMMARY [004] Conventional films produced from LLDPE and LDPE blended resins have a higher melt strength, however, with the addition of the LDPE, the mechanical properties of the films are reduced when compared to films produced from conventional LLDPE resins. [005] Melt strength and processability are correlated properties of polyethylene resins. In general, a higher melt strength provides for a polyethylene resin with improved processability. [006] Additionally, conventional polyethylene resins produced by conventional processes typically see a tradeoff between the resin’s mechanical properties and melt strength. For example, conventional radical processes, which are known to be hazardous, produce low density polyethylene (LDPE) that typically exhibit high melt strength but have poor mechanical properties. In contrast, linear low-density polyethylene (LLDPE) made via solution or gas phase processes typically have poor melt strength but excellent mechanical properties. 84689-WO-PCT/DOW 84689 WO [007] Therefore, to increase processability, some amount of LDPE may typically be blended with LLDPE in order to improve the processability and melt strength of LLDPE resins. Unfortunately, the addition of LDPE leads to a decrease in the mechanical properties of the resulting blends when compared with pure LLDPE resin. [008] Accordingly, there are needs for films having a high dart strength with high processability when compared to LLDPE and UHMWPE blends. [009] Embodiments of this disclosure include films comprising a polyethylene multimodal resin. The polyethylene multimodal resin includes the polymerized reaction product of ethylene and at least one alpha-olefin copolymer. The polyethylene multimodal resin includes a melt strength (MS) ≥ X1/I2 + y, wherein X1 is equal to 3.9, y is equal to 1.4, and I2 is a melt index of the copolymer measured according to ASTM 1238 at 2.16 kg and 190 °C, and MS is the melt strength in cN (Rheotens device, 190°C, 2.4 mm/s2, 120 mm from the die exit to the center of the wheels, extrusion rate of 38.2 s-1, capillary die of 30 mm length, 2 mm diameter and 180° entrance angle); and wherein the film comprises a normalized dart strength (DS) greater than or equal to 9,876 minus 10,512 times the density of the polyethylene multimodal resin (DS ≥ 9,876-10,512(ρ), wherein DS is measured according to ASTM 1709. [0010] In some embodiments, the film includes a polyethylene multimodal resin. The polyethylene multimodal resin includes the polymerized reaction product of ethylene and at least one alpha-olefin copolymer. In one or more embodiments, the polyethylene multimodal resin may have a melt strength (MS) ≥ x/I2 + y), in which x is equal to 3.9, y is equal to 1.4, and I2 is a melt index of the copolymer measured according to ASTM 1238 at 2.16 kg and 190 °C, and MS is the melt strength in cN (Rheotens device, 190°C, 2.4 mm/s2, 120 mm from the die exit to the center of the wheels, extrusion rate of 38.2 s-1, capillary die of 30 mm length, 2 mm diameter and 180° entrance angle). In various embodiments, the film includes a normalized machine direction (MD) tear of greater than 85 gf/mil, wherein MD tear is measured according to ASTM D1922-15. [0011] These and embodiments are described in more detail in the following Detailed Description in conjunction with the appended drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0012] The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with l