Multi-layer, ethylene polymer-based films with novel polypropylene blend-based stiffening layer

Patent metadata

Field	Value
Publication number	US-9283736-B2
Application number	US-201113086579-A
Country	US
Kind code	B2
Filing date	Apr 14, 2011
Priority date	Apr 16, 2010
Publication date	Mar 15, 2016
Grant date	Mar 15, 2016

Abstract

This invention discloses a multi-layer film for making pouches for containing flowable materials, said multi-layer film comprising generally five layers in order: inner sealant-layer, first interposed layer, the core layer, second interposed layer, and the outer sealant layer. The sealant and core layers are ethylene-based, and the interposed layers are polypropylene-based. The multi-layer film thickness is in the range of from about 35 microns to about 66 microns. The interposed layers comprise a novel polypropylene blend with a major component polypropylene and a minor component polypropylene, wherein the minor component polypropylene is a heterogeneous polypropylene interpolymer with a density in the range of from about 0.875 to about 0.91 g/cm 3 .

First claim

The invention claimed is:

1. A multi-layer film for making pouches for containing flowable materials, said multi-layer film comprising the following layers in order, from an at least one inner sealant-layer to an at least one outer sealant-layer:
(A) said at least one inner sealant-layer comprising polyethylene that is selected from the group consisting of:
(i) an at least one low-density ethylene-alpha-olefin copolymer,
(ii) a blend of said at least one low-density ethylene-alpha-olefin homopolymer, wherein said ethylene homopolymer is made in a high-pressure polymerization process; and
(iii) a blend of said at least one low-density ethylene-alpha-olefin copolymer and an at least one ethylene copolymer, wherein said ethylene copolymer is made in a high-pressure polymerization process;

(B) a first at least one interposed layer adjacent to said at least one inner sealant-layer, said first at least one interposed layer comprising:
(i) an at least one polypropylene blend comprising a major component
polypropylene and a minor component polypropylene, wherein said major component polypropylene in the range of from about 50% to 90% of weight of said first at least one interposed layer, and said minor component polypropylene is in the range of from about 10% to about 49% of weight of said first at least one interposed layer;
(ii) optionally, an at least one ethylene-alpha-olefin copolymer; and
(iii) optionally, a second ethylene-alpha-olefin copolymer that is not the same as said at least one ethylene-alpha-olefin copolymer in (B)(ii);
wherein the centerline of said first at least one interposed layer is closer to the centerline of said at least one inner sealant-layer than to the centerline of said multi-layer film;

(C) at least one core layer, adjacent to said first at least one interposed layer, said at least one core layer comprising polyethylene that is selected from the group consisting of:
(i) at least one low-density ethylene-alpha olefin copolymer,
(ii) a blend of said at least one low-density ethylene-alpha-olefin copolymer and an at least one ethylene homopolymer, wherein said ethylene homopolymer is made in a high-pressure polymerization process; and
(iii) a blend of said at least one low-density ethylene-alpha-olefin copolymer and an at least one ethylene copolymer, wherein said ethylene copolymer is made in a high-pressure polymerization process;

(D) a second at least one interposed layer adjacent to said at least one core
(i) an at least one polypropylene blend comprising a major component polypropylene and a minor component polypropylene, wherein said major component polypropylene in the range of from about 50% to 90% of weight of said first at least one interposed layer, and said minor component polypropylene is in the range of from about 10% to about 49% of weight of said first at least one interposed layer;
(ii) optionally, an at least one ethylene-alpha-olefin copolymer; and
(iii) optionally, a second ethylene-alpha-olefin copolymer that is not the same as said at least one ethylene-alpha-olefin copolymer in (D)(ii);
wherein the centerline of said second at least one interposed layer is closer to the centerline of said at least one outer sealant-layer than to the centerline of said multi-layer film; and

(E) said at least one outer sealant-layer, comprising polyethylene that is selected from the group consisting of:
(i) an at least one low-density ethylene-alpha-olefin copolymer,
(ii) a blend of said at least one low-density ethylene-alpha-olefin copolymer and an at least one ethylene homopolymer, wherein said ethylene homopolymer is made in a high-pressure polymerization process; and
(iii) a blend of said at least one low-density ethylene-alpha-olefin copolymer and an at least one ethylene copolymer, wherein said ethylene copolymer is made in a high-pressure polymerization process;
wherein said multi-layer film thickness is in the range of from about 35 microns to about 66 microns;
wherein a combined thickness of said first at least one interposed layer and said second at least one interposed layer is in the range of from about 10% to about 27% of the total thickness of said multi-layer film;
wherein a combined thickness of said inner sealant-layer and said outer sealant-layer is in the range of from about 10% to about 27% of the total thickness of said multi-layer film.

2. The multi-layer film as recited in claim 1 , wherein said multi-layer film thickness is in the range of from about 38 microns to about 63 microns.

3. The multi-layer film as recited in claim 1 , wherein said multi-layer film thickness is in the range of from about 44 microns to about 60 microns.

4. The multi-layer film as recited in claim 1 , wherein said multi-layer film thickness is in the range of from about 47 microns to about 59 microns.

5. The multi-layer film as recited in claim 1 , wherein said multi-layer film thickness is selected from the group consisting of about 45 microns, about 46 microns, about 47 microns, about 48 microns, about 49 microns, about 50 microns, about 51 microns, about 52 microns, about 53 microns, about 54 microns, about 55 microns, about 56 microns, about 57 microns and about 58 microns.

6. The multi-layer film as recited in claim 1 , wherein said at least one inner sealant-layer or said at least one outer sealant layer comprises:
(i) from about 80 to about 98 parts by weight of said low-density copolymer of ethylene and an at least one C 4 -C 10 alpha-olefin manufactured in a polymerization process using a single-site polymerization catalyst, with a density in the range of from about 0.909 to about 0.935 g/cm 3 and a melt-index in the range of from about 0.5 to about 1.5, and
(ii) from about 0 to about 15 parts by weight of an additional at least one low-density copolymer of ethylene and an at least one C 4 -C 10 alpha-olefin, which is an ultra-low density copolymer of ethylene and at least one C 4 -C 10 alpha-olefin manufactured in a polymerization process using a single-site polymerization catalyst, with a density in the range of from about 0.859 to about 0.888 g/cm 3 and a melt-index in the range of from about 0.4 to about 0.6 dg/min.

7. The multi-layer film as recited in claim 1 , wherein said at least one inner sealant-layer or said at least one outer sealant-layer further comprises from about 0 to about 15 parts by weight of said at least one ethylene homopolymer manufactured in a high pressure polymerization process or said at least one ethylene copolymer manufactured in a high pressure polymerization process, wherein said at least one ethylene homopolymer has a density in the range of from about 0.918 to about 0.923 g/cm 3 and a melt-index in the range of from about 0.1 to 1.1 dg/min, and said at least one ethylene copolymer has a density in the range of from about 0.930 to about 0.960 g/cm 3 and a melt-index in the range of from about 0.1 to about 10 dg/min.

8. The multi-layer film of claim 6 , wherein said low-density copolymer of ethylene and at least one C 4 -C 10 alpha-olefin, or said at least one ultra-low density copolymer of ethylene and at least one C 4 -C 10 alpha-olefin is selected from ethylene/butene-1 copolymers, ethylene/hexene1 copolymers, ethylene/octene-1 copolymers, ethylene/octene-1/butene1 terpolymers and ethylene/hexene-1/butene-1 terpolymers.

9. The multi-layer film as recited in claim 1 , wherein, in said first at least one interposed layer or in said at least second interposed layer:
(i) said at least one polypropylene blend is in the range of from about 70 to about 100 parts by weight of said first at least one interposed layer or of said second at least one interposed layer, wherein said polypropylene blend comprises two components, the first compo

Assignees

• Breck Alan Keith
• Liqui Box Corp

Inventors

• Breck Alan Keith

Classifications

• Y10T428/24959

  of adhesive layers · CPC title

• B65B9/20

  the webs being formed into tubes in situ around the filling nozzles · CPC title

• B32B27/32 Primary

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

• B32B27/327

  comprising polyolefins obtained by a metallocene or single-site catalyst · CPC title

• B32B27/08

  of synthetic resin · CPC title