Barrier film for food packaging

Patent metadata

Field	Value
Publication number	US-9850369-B2
Application number	US-201715409606-A
Country	US
Kind code	B2
Filing date	Jan 19, 2017
Priority date	Nov 17, 2006
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Barrier films are prepared from a blend of two high density polyethylene blend components and a high performance organic nucleating agent. The two high density polyethylene blend components have substantially different melt indices. Large reductions in the moisture vapor transmission rate of the film are observed in the presence of the nucleating agent when the melt indices of the two blend components have a ratio of greater than 10/1. The resulting barrier films are suitable for the preparation of packaging for dry foods such as crackers and breakfast cereals.

First claim

What is claimed is:

1. A polyethylene film comprising at least one layer, wherein said layer is prepared from a mixture comprising;
a) from about 5 to about 60 weight percent, based on the total weight of said mixture, of a component a) comprising at least one high density polyethylene having a density of from 0.950 to 0.975 g/cc and a high melt index I 2 ;
b) from about 95 to about 40 weight percent, based on the total weight of said mixture, of a component b) comprising at least one high density polyethylene having a density from about 0.950 to about 0.970 g/cc and a low melt index I 2 ′, and;
c) from about 100 to about 3,000 ppm of a calcium salt of 1,2-cyclohexanedicarboxylic acid;

wherein, a melt index ratio, defined by dividing said high melt index I 2 of said component a) by said low melt index I 2 ′ of said component b), is greater than 10/1;
wherein the water vapor transmission rate of said polyethylene film is improved, by being from about 20% to about 53% lower, relative to a control polyethylene film of the same composition but not containing said calcium salt of 1,2-cyclohexanedicarboxylic acid;
wherein density is measured according to ASTM D 1505, and;
wherein melt index is measured according to ASTM D 1238 when conducted at 190° C. using a 2.16 kg weight.

2. The polyethylene film according to claim 1 , wherein said mixture has a density from about 0.955 to about 0.967 g/cc.

3. The polyethylene film according to claim 1 , wherein said mixture has a melt index, I 2 , from about 0.8 to about 8 grams/10 minutes.

4. The polyethylene film according to claim 1 , wherein said film is a multilayer film comprising at least one layer comprising said mixture.

5. A method for improving the barrier properties of a polyethylene film, said method comprising the steps of converting into a film a mixture comprising;
a) from about 5 to about 60 weight percent, based on the total weight of said mixture, of a component a) comprising at least one high density polyethylene having a density of from about 0.950 to about 0.975 g/cc and a high melt index I 2 ;
b) from about 95 to about 40 weight percent, based on the total weight of said mixture, of a component b) comprising at least one high density polyethylene having a density of from about 0.950 to about 0.970 g/cc and a low melt index I 2 ′, and;
c) from about 100 to about 3,000 ppm of a calcium salt of 1,2-cyclohexanedicarboxylic acid;

wherein, a melt index ratio, defined by dividing said high melt index I 2 of said component a) by said low melt index I 2 ′ of said component b), is greater than 10/1;
wherein the water vapor transmission rate of said polyethylene film is improved, by being from about 20% to about 53% lower, relative to a control polyethylene film of the same composition but not containing said calcium salt of 1,2-cyclohexanedicarboxylic acid;
wherein density is measured according to ASTM D 1505, and;
wherein melt index is measured according to ASTM D 1238 when conducted at 190° C. using a 2.16 kg weight.

6. The method of claim 5 , wherein said mixture has a density from about 0.955 to about 0.967 g/cc.

7. The method of claim 5 , wherein said mixture has a melt index, I 2 , from about 0.8 to about 8 grams/10 minutes.

Assignees

• Nova Chemicals International Sa

Inventors

• Aubee Norman Dorien Joseph
• Checknita Douglas
• Chisholm P Scott
• Lam Patrick
• Marshall Sarah
• Sauvageau Denny Paul
• Tikuisis Tony
• Chuang Tingting Yu

Classifications

• B29K2105/0005

  containing compounding ingredients (releasing, lubricating or separating agents B29C33/56, fibers B29K2105/08, B29K2105/12; fillers B29K2105/16, recycled material B29K2105/26) · CPC title

• B29L2007/008

  Wide strips, e.g. films, webs · CPC title

• B32B27/32

  comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} · CPC title

• Y10T428/27

  Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.] · CPC title

• C08K5/0083

  Nucleating agents promoting the crystallisation of the polymer matrix · CPC title