CN-116438072-B - Multilayer structure and article with coating

Abstract

The present invention provides multilayer structures and articles formed therefrom. The multilayer structure according to embodiments disclosed herein comprises a substrate layer and a coating layer, wherein the substrate layer is coated with the coating layer. The coating comprises a blend of high pressure low density polyethylene and a masterbatch composition. When the coating is applied to the substrate layer, the coating may have improved necking reduction and maintenance or improvement of blade coating during processing.

Inventors

• M. G. De Oliveira
• M. B. Bike
• J.C. Gomes
• C. D. Willey

Assignees

• 陶氏环球技术有限责任公司

Dates

Publication Date

20260508

Application Date

20211116

Priority Date

20201120

Claims (10)

1. 1. A multilayer structure, the multilayer structure comprising: (a) A base layer comprising a base, and (B) A coating comprising a polyethylene composition, the polyethylene composition comprising: (i) 90 to 99.5wt% of a high pressure low density polyethylene having a density in the range of 0.916g/cm 3 to 0.940g/cm 3 , a melt index I 2 in the range of 2.0g/10min to 30.0g/10min and a vinyl unsaturation of less than 0.10 vinyl groups per 1,000 total carbon atoms, based on the total weight of the polyethylene composition, and (Ii) 0.5 to 10wt% of a masterbatch composition comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half life of less than 200 seconds and a decomposition energy of greater than-250 kJ/mol at 220 ℃, and wherein the polyethylene resin has a density in the range of 0.900g/cm 3 to 0.970g/cm 3 , a melt index in the range of 0.01g/10min to 100g/10 min; Wherein the substrate layer is coated with the coating, and wherein the density is measured according to ASTM D792, the melt index is measured according to ASTM D1238 at 190 ℃,2.16kg, and the vinyl unsaturation is determined by 1 H NMR, wherein a double presaturation experiment is run with a modified pulse sequence, 100 scans, DS 4, AQ 1.64s, presaturation time D1 1s, relaxation delay D13 s, and the region between 4.95ppm to 5.15ppm is integrated.
2. 2. The multilayer structure of claim 1 wherein the polyethylene composition comprises 96 to 99.5 weight percent of the high pressure low density polyethylene and 0.5 to 4 weight percent of the masterbatch composition.
3. 3. The multilayer structure according to claim 1 or 2, wherein the amount of free radical generator is less than 100ppm relative to the total amount of polyethylene resin.
4. 4. A multilayer structure according to any one of claims 1 to 3, wherein the free radical generator has a half-life at 220 ℃ of between 60 seconds and 120 seconds.
5. 5. The multilayer structure of any one of claims 1 to 4, wherein the radical generator has a molecular weight of 200 daltons to 1,000 daltons as determined by high temperature gel permeation chromatography.
6. 6. The multilayer structure according to any one of claims 1 to 5, wherein the free radical generator is a cyclic peroxide.
7. 7. The multilayer structure according to any one of claims 1 to 6, wherein the substrate of the substrate layer comprises at least one of a film, nonwoven, woven, scrim, foil, carpet, plastic, saran, paper, cellulose, or metal.
8. 8. A method for forming a multi-layer structure, the method comprising: (a) Providing 90 to 99.5wt% of a high pressure low density polyethylene having a density in the range of 0.916g/cm 3 to 0.940g/cm 3 , a melt index I 2 in the range of 2.0g/10min to 30.0g/10min, and a vinyl unsaturation of less than 0.10 vinyl groups per 1,000 total carbon atoms; (b) Providing 0.5 to 10wt% of a masterbatch composition comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds and a decomposition energy of greater than-250 kJ/mol at 220 ℃, and wherein the polyethylene resin has a density in the range of 0.900g/cm 3 to 0.970g/cm 3 , a melt index in the range of 0.01g/10min to 100g/10 min; (c) Reacting the high pressure low density polyethylene with the masterbatch composition to form a polyethylene composition, wherein wt% is based on the total weight of the polyethylene composition, and (D) Extrusion coating the polyethylene composition as a coating onto a substrate layer comprising a substrate to form the multilayer structure, and Wherein the density is measured according to ASTM D792, the melt index is measured according to ASTM D1238 at 190 ℃,2.16kg, and the vinyl unsaturation is determined by 1 H NMR, a double presaturation experiment is run with a modified pulse sequence, 100 scans, DS 4, AQ 1.64s, presaturation time D11 s, relaxation delay D13 s, and the region between 4.95ppm to 5.15ppm is integrated.
9. 9. The method of claim 8 wherein the coating has a neck-in of less than 10.16 cm at 134.11 meters/minute during extrusion coating of the polyethylene composition as the coating.
10. 10. The method of claim 8 or 9, wherein the coating has a neck-in of less than 8.89 cm at 268.22 meters/minute during extrusion coating of the polyethylene composition as the coating.

Description

Multilayer structure and article with coating Technical Field The present invention relates to multilayer structures comprising a substrate layer and a coating layer, to articles comprising such multilayer structures, and to methods for preparing such multilayer structures. Background Multilayer structures comprising extrusion coated substrates (i.e., substrate layers coated with a coating) are widely used in packaging applications. To prepare such structures, the polyolefin coating may be adhered or coated onto the substrate by extrusion coating. When added to the substrate layer, the coating may improve or impart desirable properties (e.g., barrier, seal, and toughness properties). However, challenges exist in producing and manufacturing extrusion coated substrates. For example, low density polyethylenes are commonly used as polyolefin coatings due to their high melt strength and the presence of long chain branching. However, extrusion coating of low density polyethylene onto a substrate (e.g., film) may result in increased necking when the production line is running at its highest target speed. Thus, there remains a need for multilayer structures including coatings and resin designs that exhibit reduced necking while maintaining or improving blade coating performance. Disclosure of Invention The present invention provides multilayer structures comprising a substrate layer and a coating layer, wherein the substrate layer is coated with the coating layer. According to embodiments, the coating comprises a polyethylene composition comprising a high pressure low density polyethylene and a masterbatch composition, and when the coating is applied to a substrate layer, the coating may exhibit desirable characteristics such as reduced necking and maintenance or improved blade coating. In one aspect, the present invention provides a multilayer structure comprising (a) a substrate layer comprising a substrate, and (b) a coating layer comprising a polyethylene composition comprising (I) a high pressure low density polyethylene having a density in the range of 0.916g/cm 3 to 0.940g/cm 3, a melt index (I 2) in the range of 2.0g/10min to 30.0g/10min, and less than 0.20 vinyl groups per 1,000 total carbon atoms, and (ii) a masterbatch composition comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half life of less than 200 seconds and a decomposition energy above-250 kJ/mol at 220 ℃, and wherein the polyethylene resin has a density in the range of 0.900g/cm 3 to 0.970g/cm 3, a melt index in the range of 0.01g/10min to 100g/10min, wherein the coating layer is coated with the substrate layer. In another aspect, the present invention provides an article, such as a package, comprising any of the multilayer structures of the invention disclosed herein. In another aspect, the present invention provides a method for forming the multilayer structure of the present invention comprising (a) providing a high pressure low density polyethylene having a density in the range of 0.916g/cm 3 to 0.940g/cm 3, a melt index (I 2) in the range of 2.0g/10min to 30.0g/10min, and less than 0.20 vinyl groups per 1,000 total carbon atoms, (b) providing a masterbatch composition comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half life of less than 200 seconds and a decomposition energy of greater than-250 kJ/mol at 220 ℃, and wherein the polyethylene resin has a density in the range of 0.900g/cm 3 to 0.970g/cm 3, a melt index in the range of 0.01g/10min to 100g/10min, (C) reacting the high pressure low density polyethylene with the masterbatch composition, and forming the polyethylene composition, and (d) extruding the polyethylene composition as a multilayer substrate layer to form the multilayer structure. These and other embodiments are described in more detail in the detailed description. Detailed Description Aspects of the disclosed multilayer structures, articles, and methods for making such multilayer structures are described in more detail below. However, the present disclosure should not be construed as limiting the embodiments set forth below. As used herein, the term "polymer" means a polymeric compound prepared by polymerizing the same or different types of monomers. The generic term polymer thus embraces the term homopolymer (employed to refer to polymers prepared from only one type of monomer) and the term copolymer or interpolymer. Trace impurities (e.g., catalyst residues) may be incorporated into and/or within the polymer. The polymer may be a single polymer, a blend of polymers, or a mixture of polymers, including a mixture of polymers formed in situ during polymerization. As used herein, the term "polyethylene" or "ethylene-based polymer" shall mean a polymer comprising a majority amount (> 50 mol%) of units derived from ethylene monomers. This includes polyethylene homopolymers or copolymers (meaning units derived from tw