High oxygen and water barrier multilayer film

Abstract

A multilayer plastic film comprising polyethylene outer layers with inner layers of additional polyethylene adjacent to tie layers of adhesive bonded to a blended polyamide and polyvinyl alcohol core. This structure results in excellent oxygen and water barrier properties. The film can be coextruded in a blown film process that results in a durable barrier film without the sacrifice of optical properties. Film applications include, but are not limited to, food packaging such as bags, liners, pouches, shrink bags, and chubs. In certain embodiments, the film can also be used for food packaging, including packaging of meat, cheese, milk, condiments, salad dressings, or any other oxygen sensitive products.

Claims

1. A multilayer film comprising: A first layer comprising a blend of a linear low density polyethylene, an anti-block material and a slip material; A second layer comprising a linear low density polyethylene; A third layer comprising a blend of one or more linear low density polyethylenes; A fourth layer comprising a blend of polyamide and amorphous polyvinyl alcohol; A fifth layer comprising a blend of one or more linear low density polyethylenes; A sixth layer comprising a linear low density polyethylene; and A seventh layer comprising a blend of one or more linear low density polyethylenes, an anti-block material and a slip material, wherein the polyamide comprises polyamide 6,66.

2. The film of claim 1 wherein the linear low density polyethylene in the first layer comprises a single site catalyzed linear low density polyethylene.

3. The film of claim 1 wherein the linear low density polyethylene in the second layer comprises an octene linear low density polyethylene.

4. The film of claim 1 wherein the third layer comprises a blend of a super hexene linear low density polyethylene and a maleic anhydride grafted linear low density polyethylene.

5. The film of claim 1 wherein the fifth layer comprises a blend of a super hexene linear low density polyethylene and a maleic anhydride grafted linear low density polyethylene.

6. The film of claim 1 wherein the sixth layer comprises an octene linear low density polyethylene.

7. The film of claim 1 wherein the seventh layer comprises a blend of an octene linear low density polyethylene, metallocene catalyzed linear low density polyethylene, an anti-block material and a slip material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The FIGURE Shows a cross-section of a blown, thermoplastic coextruded film comprising seven layers.

DETAILED DESCRIPTION

(2) As shown in the FIGURE, in a particular embodiment, the first layer of the film provided herein as an embodiment comprises a single site catalyzed linear low density polyethylene (LLDPE) blended with a master batch of anti-block material and a master batch of slip material. Nova FPs117C is one such LLDPE, while Ingenia IP1091 anti-block and Ingenia IP1065 slip are examples of possible master batches that can be employed in the first layer.

(3) Without being limited by theory, in the first layer, the LLDPE provides strength and a platform for the anti-block material, which prevents the outside of the film from sticking to itself when multiple sheets are in contact. Common situations where sticking could occur include when the film is wound into a roll or fashioned into a bag or pouch. The slip materials provide the desired coefficient of friction during film to film contact or film to metal contact. In certain embodiments, the coefficient of friction is in the range between about 0.05 to about 0.50, in one embodiment, between about 0.10 and about 0.25. In certain embodiments, the film can slide on materials, or allow materials to slide on it, without such low friction that the film cannot be held or such high friction that the film wrinkles.

(4) The second layer is comprised of an octene linear low density polyethylene, such as FP120D available from Nova.

(5) The third layer is comprised of a blend of super hexene LLDPE and maleic anhydride grafted linear low density polyethylene (MAH modified LLDPE). ExxonMobil NTX-101 is a suitable super hexene LLDPE, while DuPont Bynel 4164 is a suitable MAH modified LLDPE.

(6) Without being limited by theory, these first 3 layers provide a moisture barrier to keep water from passing into and through the film.

(7) The fourth layer is comprised of a blend of polyamide (PA) and polyvinyl alcohol (PVA). In one embodiment, the PVA is amorphous. A function of this layer is to provide oxygen barrier property to the film. In one embodiment, the PA is comprised of polyamide 6.66. BASF C40 PA and Soarus OKS-8049P PVA can be used to make the fourth layer of the film. In one embodiment, the fourth layer is the oxygen barrier layer.

(8) The fifth layer is comprised of a blend of super hexene LLDPE and MAH modified LLDPE. ExxonMobil NTX-101 is a suitable super hexene LLDPE, while DuPont Bynel 4164 is a suitable MAH modified LLDPE.

(9) The sixth layer is comprised of an octene linear low density polyethylene, such as FP120D available from Nova.

(10) The seventh layer is comprised of a blend of octene linear low density polyethylene, metallocene catalyzed linear low density polyethylene, a master batch of anti-block and a master batch of slip materials. Nova FP120D is one such octene LLDPE, ExxonMobil 1012HA is a suitable metallocene catalyzed LLDPE, while Ingenia IP1091 anti-block and Ingenia IP1065 slip are examples of possible master batches that can be used in the seventh layer.

(11) In certain embodiments, the first layer is the inner layer and the seventh layer is the outer layer.

(12) In certain embodiments, the films provided herein have an oxygen barrier comprising polyvinyl alcohol. Without being limited by theory, it is believed that films provided herein having an oxygen barrier comprising polyvinyl alcohol provide about 10 to 15 times the oxygen barrier than films without an oxygen barrier comprising polyvinyl alcohol.

(13) Without being limited by theory, it is thought that the structure of LLDPE and additive outer layers with a core of PA and PVA provides a high oxygen and water barrier film.

(14) In certain embodiments, provided herein are methods for using films provided herein as bags, liners, pouches, shrink bags, and chubs. In certain embodiments, the film can also be used for food packaging, including packaging of meat, cheese, milk, condiments, salad dressings, or any other oxygen sensitive products.

Example 1

(15) A film was made with the following structure:

(16) TABLE-US-00001 % Layer Thickness Description 1 20.00% Nova FPs117C Single Site Catalyzed LLDPE Ingenia IP1091 Anti-block Masterbatch Ingenia IP1065 Slip Masterbatch 2 15.00% Nova FP120D Octene LLDPE 3 10.00% ExxonMobil NTX-101 Super Hexene LLDPE DuPont Bynel 4164 MAH Modified LLDPE 4 10.00% BASF C40 Polyamide Soarus OKS-8049P PVA 5 10.00% ExxonMobil NTX-101 Super Hexene LLDPE DuPont Bynel 4164 MAH Modified LLDPE 6 15.00% Nova FP120D Octene LLDPE 7 20.00% Nova FP120D Octene LLDPE ExxonMobil 1012HA Metallocene Catalyzed LLDPE Ingenia IP1091 Anti-block Masterbatch Ingenia IP1065 Slip Masterbatch

(17) The film was produced at a total average thickness of 4.5 mils with the first layer averaging 0.90 mils, the second layer averaging 0.68 mils, the third layer averaging 0.45 mils, the fourth layer averaging 0.45 mils, the fifth layer averaging 0.45 mils, the sixth layer averaging 0.68 mils, and the seventh layer averaging 0.90 mils. The desired range is +/10% for both the total film thickness and the thicknesses of each layer. In certain embodiments, the films provided herein can be made using blown film, cast film, or double bubble processes.

(18) Film Properties:

(19) In one embodiment, the oxygen transmission rate (OTR) was measured using ASTM D-3985 at 73 F. at three different levels of relative humidity, three times each with the following results:

(20) TABLE-US-00002 OTR (cc/m.sup.2/day) Relative Humidity (%) Measurement 1 Measurement 2 Measurement 3 50 0.286 0.496 0.263 75 0.491 1.250 0.666 90 1.650 3.396 2.006

(21) In certain embodiments, films provided herein have an OTR (cc/m.sup.2/day) of less than about 25, less than about 20, less than about 15, less than about 10, less than about 5, less than about 4, less than about 3, less than about 2, less than about 1 or less than about 0.5 at a relative humidity of 50% as measured using ASTM D-3985.

(22) In certain embodiments, films provided herein have an OTR (cc/m.sup.2/day) of less than about 25, less than about 20, less than about 15, less than about 10, less than about 5, less than about 4, less than about 3, less than about 2, less than about 1.5, less than about 1 or less than about 0.5 at a relative humidity of 75% as measured using ASTM D-3985.

(23) In certain embodiments, films provided herein have an OTR (cc/m.sup.2/day)] of less than about 25, less than about 20, less than about 15, less than about 10, less than about 5, less than about 4, less than about 3, less than about 2 or less than about 1 at a relative humidity of 90% as measured using ASTM D-3985.

Example 2

(24) A film was made similar to example 1, except no PVA was added to the fourth layer of the film.

(25) The film was produced at a total average thickness of 4.5 mils with the first layer averaging 0.90 mils, the second layer averaging 0.68 mils, the third layer averaging 0.45 mils, the fourth layer averaging 0.45 mils, the fifth layer averaging 0.45 mils, the sixth layer averaging 0.68 mils, and the seventh layer averaging 0.90 mils.

(26) Film Properties:

(27) The oxygen transmission was measured at 73 F. at three different levels of relative humidity, three times each with the following results:

(28) TABLE-US-00003 OTR (cc/m.sup.2/day) Relative Humidity (%) Measurement 1 Measurement 2 Measurement 3 50 48.745 55.701 54.017 75 49.892 56.508 55.586 90 52.709 58.884 58.558

(29) Summary Table for Example 1 and Example 2 Test Results Comparison

(30) TABLE-US-00004 Relative Humidity OTR (cc/m.sup.2/day) Example (%) Measurement 1 Measurement 2 Measurement 3 1 50 0.286 0.496 0.263 1 75 0.491 1.250 0.666 1 90 1.650 3.396 2.006 2 50 48.745 55.701 54.017 2 75 49.892 56.508 55.586 2 90 52.709 58.884 58.558

(31) The film of Example 1 provides an oxygen barrier and a water barrier. The film of Example 2 does not provide a desirable shelf life and leads to undesirable conditions in the end use, such as food spoilage, odor, and bacteria growth, because of the high OTR of the film.