Process of preparing a pouch for packaging flowable materials

• US 5,508,051 A
• Filed: 10/31/1994
• Issued: 04/16/1996
• Est. Priority Date: 06/24/1993
• Status: Expired due to Term

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Restaino, Michael C., Falla, Daniel J.
• Primary Examiner(s): Czaja, Donald E.
• Assistant Examiner(s): Cano, Milton I.
• Application Number:
  US08/332,201
• Time in Patent Office: 533 Days
• Field of Search: 426/115, 426/106, 426/127, 426/130, 426/392, 426/410, 426/413, 426/415, 428/34.9, 428/35.1, 428/35.2, 428/35.7, 428/213, 428/500, 428/515, 428/518, 383/109, 383/113, 525/240, 526/348.5, 220/569, 220/415, 220/DIG. 11, 206/524.3
• US Class Current: 426/392
• CPC Class Codes: B32B 2323/04 Polyethylene
• CPC Class Codes: B32B 2323/046 LDPE, i.e. low density polyethylene
• CPC Class Codes: B32B 2439/46 Bags
• CPC Class Codes: B32B 2439/70 Food packaging
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 37/153 at least one layer is extruded and immediately laminated while in semi-molten state
• CPC Class Codes: B65D 75/008 Standing pouches, i.e. "Standbeutel"
• CPC Class Codes: Y10T 428/1328 Shrinkable or shrunk [e.g., due to heat, solvent, volatile agent, restraint removal, etc.]
• CPC Class Codes: Y10T 428/1334 Nonself-supporting tubular film or bag [e.g., pouch, envelope, packet, etc.]
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31909 Next to second addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/3192 Next to vinyl or vinylidene chloride polymer

Abstract

An environmentally friendly polymer film pouch made from a homogeneously branched substantially linear ethylene interpolymer film structure for the packaging of flowable materials such as milk, the pouch includes, for example, a multilayer film structure such as a two-layer or a three-layer coextruded film containing at least one seal layer of a homogeneously branched substantially linear polyethylene. A process for making a pouch for packaging flowable materials using a homogeneously branched substantially linear ethylene interpolymer film structure is also disclosed.

Claims

1. A process of preparing a pouch in a vertical form containing a flowable material comprising the steps of forming a film structure;

forming the film structure into a tubular member;

heat-sealing longitudinal edges and first transverse end of the tubular member to form the pouch;

filling the pouch with the flowable material; and

sealing a second transverse end of the tubular member, the film structure having at least one layer comprising;

(a) from 10 to 100 percent by weight of at least one homogeneously branched substantially linear ethylene/α

-olefin interpolymer, and

(b) from 0 to 90 percent by weight of at least one polymer selected from the group consisting of a heterogeneously branched linear ethylene/C₃ -C₁₈ α

-olefin copolymer, a high-pressure low density polyethylene and an ethylene/vinyl acetate copolymer.

4. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer is a copolymer of ethylene and a C₃ -C₂₀ α

-olefin.

5. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer is an ethylene/1-octene copolymer.

6. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer is an ethylene/1-hexene copolymer.

7. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer is an ethylene/1-butene copolymer.

8. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer is an ethylene/propene copolymer.

9. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer has a density from about 0.85 g/cm³ to about 0.94 g/cm³.

10. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer has a melt index from about 0.01 g/10 minutes to about 10 g/10 minutes.

11. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer has a I₁₀ /I₂ ratio from about 7 to about 20.

12. The process of claims 1 or 2 wherein said homogeneously branched Substantially linear ethylene/α

-olefin interpolymer has a M_w /M_n from about 1.5 to about 2.5.

13. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer has a M_w /M_n of about 2.

14. The process of claims 1 or 2 wherein said film structure has a heat sealing range from about 50°

C. to about 160°

C.

15. The process of claims 1 or 2 wherein said film structure has a heat sealing range from about 75°

C. to about 130°

C.

16. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer has a melting point range from about 50°

C. to about 130°

C.

17. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α

-olefin interpolymer has a melting point range from about 55°

C. to about 110°

C.

2. A process of preparing a pouch in a vertical form containing a flowable material comprising the steps of forming a film structure;

forming the film structure into a tubular member;

heat-sealing longitudinal edges and first transverse end of the tubular member to form the pouch;

filling the pouch with the flowable material; and

sealing a second transverse end of the tubular member, the film structure having at least one layer comprising;

(I) (a) from 10 to 100 percent by weight of at least one homogeneously branched substantially linear ethylene/α

-olefin interpolymer, and

(b) from 0 to 90 percent by weight of at least one polymer selected from the group consisting of a heterogeneously branched linear ethylene/C₃ -C₁₈ α

olefin copolymer, a high-pressure low density polyethylene and an ethylene/vinyl acetate copolymer; and

at least one layer comprising;

(II) a heterogeneously branched linear ethylene/C₃ -C₁₈ α

-olefin copolymer having a density greater that about 0.87 g/cm³ and a melt index from about 0.1 to about 10 g/10 minutes.

3. The process of claim 2 wherein the film structure includes at least one other layer comprising:

(III) a high-pressure low density polyethylene having a density from about 0.916 to about 0.93 g/cm³ and a melt index from about 0.1 to about 10 g/10 minutes.