Barrier film for food packaging

Patent metadata

Field	Value
Publication number	US-10066093-B2
Application number	US-201715811847-A
Country	US
Kind code	B2
Filing date	Nov 14, 2017
Priority date	Nov 17, 2006
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

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 barrier film comprising at least one extruded polyethylene layer, wherein said at least one extruded polyethylene layer comprises:
I) an organic nucleating agent and
II) a high density polyethylene blend composition comprising:
a) from 5 to 60 weight % of at least one high density polyethylene blend component a) having a density of from 0.950 to 0.975 g/cc and a high melt index, I 2 ; and
b) from 95 to 40 weight% of at least one high density polyethylene blend component b) having a density of from 0.955 to 0.965 g/cc and a low melt index, I 2 ′;

wherein:
i) said organic nucleating agent is a calcium salt of 1,2-cyclohexanedicarboxylic acid and added in an amount of from 100 to 3000 parts per million based on the weight of said high density polyethylene blend composition;
ii) an I 2 ratio, obtained by dividing said I 2 value of said blend component a) by said I 2 ′ value of said blend component b) is greater than 10/1;
iii) 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 organic nucleating agent; and
iv) density is measured according to ASTM D 1505 and melt index is measured according to ASTM D 1238 when conducted at 190° C. using a 2.16 kg weight.

2. The barrier film of claim 1 wherein said high density polyethylene blend composition comprises from 20 to 40weight % of said component a) and from 80 to 60 weight% of said component b).

3. The barrier film of claim 1 wherein said blend component a) is further characterized by having a molecular weight distribution, Mw/Mn, of from 2 to 4.

4. The barrier film of claim 1 wherein said high density polyethylene blend composition has a melt index from 0.8to 8 grams/10 minutes.

5. The barrier film of claim 1 wherein said high density polyethylene blend composition has a density from 0.955to 0.967 g/cc.

6. The barrier film of claim 1 wherein said organic nucleating agent has a melting/decomposition temperature of greater than 300° C.

Assignees

• Nova Chem Int Sa

Inventors

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

Classifications

• C08L2203/16

  used for films · CPC title

• B32B2307/7246

  Water vapor barrier · CPC title

• B29C48/10

  flexible, e.g. blown foils · CPC title

• B29K2023/086

  EVOH, i.e. ethylene vinyl alcohol copolymer · CPC title

• B32B2270/00

  Resin or rubber layer containing a blend of at least two different polymers · CPC title