Shrink films with high tear resistance, and methods of making thereof

Patent metadata

Field	Value
Publication number	US-10357948-B2
Application number	US-201415302359-A
Country	US
Kind code	B2
Filing date	Apr 16, 2014
Priority date	Apr 16, 2014
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

A multilayer ethylene-based shrink films comprising a core layer comprising a polyethylene resin, and two skin layers, wherein the core layer is positioned between the two skin layers, wherein the polyethylene resin comprises greater than 50 mol. % of the units derived from ethylene and less than 30 mol. % of the units derived from one or more alpha-olefin comonomers, has greater than 50% of the copolymer fraction eluting between 75.0° C. and 95.0° C. as determined by Crystallization Elution Fractionation (CEF), and has a density ranging from 0.915 to 0.940 g/cc, and wherein the film is biaxially-oriented.

First claim

The invention claimed is:

1. A multilayer ethylene-based shrink film comprising:
a core layer comprising a polyethylene resin; and
two skin layers, wherein the two skin layers independently comprise an ethylene-based resin having greater than 50 mol. % of the units derived from ethylene and less than 30 mol. % of the units derived from one or more alpha-olefin comonomers, and having a density ranging from 0.920 to 0.950 g/cc, and the ethylene-based resin in the two skin layers has a density that is at least 0.005 g/cc higher than the density of the polyethylene resin in the core layer;
wherein the core layer is positioned between the two skin layers; and
wherein the polyethylene resin:
comprises greater than 50 mol. % of the units derived from ethylene and less than 30 mol. % of the units derived from one or more alpha-olefin comonomers;
has greater than 50% of the copolymer fraction eluting between 75.0° C. and 95.0° C. as determined by Crystallization Elution Fractionation (CEF); and
has a density ranging from 0.915 to 0.940 g/cc; and

wherein the film is biaxially-oriented.

2. The film of claim 1 , wherein the polyethylene resin in the core layer has a melt index from 0.1 to 5 g/10 min.

3. The film of claim 1 , wherein the core layer is a blend that further comprises one or more additional polyethylene resins, wherein the blend has a density ranging from 0.915 to 0.940 g/cc and has greater than 50% of the copolymer fraction eluting between 75.0° C. and 95.0° C. as determined by Crystallization Elution Fractionation (CEF).

4. The film of claim 1 , wherein the polyethylene resin in the core layer comprises at least 40 wt. % of the core layer.

5. The film of claim 1 , wherein the core layer comprises from 50% to 95% of the total thickness of the film.

6. The film of claim 1 , wherein the ethylene-based resin in the two skin layers has a melt index from 0.1 to 5 g/10 min.

7. The film of claim 1 , wherein the film is cross-linked.

8. The film of claim 1 , wherein the film is biaxially-oriented below its highest melting point.

9. The film of claim 1 , wherein the film exhibits an increase in average tear resistance as compared to a multilayer shrink film comprising a polyethylene resin in the core layer having less than or equal to 50% of the copolymer fraction eluting between 75.0° C. and 95.0° C., as determined by Crystallization Elution Fractionation (CEF).

10. An article comprising the film of claim 1 .

Assignees

• Dow Global Technologies Llc
• Pan jian ping
• Lin Yijian
• Yun Xiao Bing
• Demirors Mehmet

Inventors

• Pan Jian-Ping
• Lin Yijian
• Yun Xiao Bing
• Demirors Mehmet

Classifications

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• B32B2439/70

  Food packaging · CPC title

• B32B2307/736

  Shrinkable · CPC title

• B32B2307/72

  Density · CPC title

• B32B2307/518

  bi-axially · CPC title