Pouch for packaging flowable materials

• US 5,364,486 A
• Filed: 11/17/1993
• Issued: 11/15/1994
• Est. Priority Date: 08/09/1991
• Status: Expired due to Term

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Ross, Allen W., Falla, Daniel J., Elliott, Robert S.
• Primary Examiner(s): Ball, Michael W.
• Assistant Examiner(s): Lorin, Francis J.
• Application Number:
  US08/154,046
• Time in Patent Office: 363 Days
• Field of Search: 156/145, 156/292, 156/308.4
• US Class Current: 156/308.4
• CPC Class Codes: B32B 1/08 Tubular products
• CPC Class Codes: B32B 2307/31 Heat sealable
• CPC Class Codes: B32B 2439/00 Containers; Receptacles closures therefor B32B2435/00
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/18 characterised by the use of special additives
• CPC Class Codes: B32B 27/306 comprising vinyl acetate or vinyl alcohol (co)polymers
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: C09J 123/0815 Copolymers of ethene with aliphatic 1-olefins
• CPC Class Codes: Y10T 428/1334 Nonself-supporting tubular film or bag [e.g., pouch, envelope, packet, etc.]
• CPC Class Codes: Y10T 428/1345 Single layer [continuous layer]
• CPC Class Codes: Y10T 428/24777 Edge feature
• CPC Class Codes: Y10T 428/2826 Synthetic resin or polymer
• CPC Class Codes: Y10T 428/31913 Monoolefin polymer

Abstract

An environmentally friendly polymer film pouch made from a polyethylene film structure for the packaging of flowable materials, for example milk, including, for example, a pouch made from a multilayer film structure such as a two-layer or a three-layer coextruded film containing at least one layer of ultra low density linear polyethylene, as a seal layer.

Claims

1. A process for preparing a pouch containing a flowable material comprising forming a film structure by either blown tube extrusion or cast extrusion, forming the film structure into a tubular member and transversely heat-sealing opposite ends of the tubular member, said tubular member comprising a film structure for a pouch container comprising (a) from 10 to 100 percent by weight of at least one polymeric seal layer of an ultra low density linear ethylene copolymer interpolymerized from ethylene and at least one alpha-olefin in the range of C₃ -C₁₀ and having (1) a density of from about 0.89 g/cm³ to less than 0.915 g/cm³, (2) a melt index of less than about 10.0 g/10 minutes and (3) (i) a hot tack or heat seal initiation temperature of less than 100°

C. at a force of at least 1N/inch (39.4N/m) or (ii) achieving a hot tack strength of at least 1N/inch (39.4N/m) at a seal bar temperature of about 110°

C. at less than 0.2 seconds using the DTC Hot Tack Strength Method or achieving a heat seal strength of at least 1 lb_f /inch (175N/m) at a seal bar temperature of about 110°

C. at less than 0.25 seconds using the DTC Heat Seal Strength Method; and

(b) from 0 to 90 percent by weight of at least one polymer selected from the group consisting of a linear copolymer of ethylene and a C₃ -C₁₈ -alpha-olefin having a density of greater than 0.916 g/cm³ and a melt index of from 0.1 to 10 g/10 minutes, a high-pressure low density polyethylene having a density of from 0.916 to 0.930 g/cm³ and a melt index of from 0.1 to 10 g/10 minutes and ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate from 2.2;

1 to 24;

1 and a melt index of from 0.2 to 10 g/10 minutes.

2. A process for preparing a pouch containing a flowable material comprising forming a film structure by either blown tube extrusion or cast extrusion, forming the film structure into a tubular member and transversely heat sealing opposite ends of the tubular member, said tubular member comprising:

(I) (a) from 10 to 100 percent by weight of at least one polymeric seal layer of an ultra low density linear ethylene copolymer interpolymerized from ethylene and at least one alpha-olefin in the range of C₃ -C₁₀ and having (1) a density of from about 0.89 g/cm ³ to less than 0.915 g/cm³, (2) a melt index of less than about 10.0 g/10 minutes and (3) (i) a hot tack or heat seal initiation temperature of less than 100°

C. at a force of at least 1N/inch (39.4N/m) or (ii) achieving a hot tack strength of at least 1N/inch (39.4N/m) at a seal bar temperature of about 110°

C. at less than 0.2 seconds using the DTC Hot Tack Strength Method or achieving a heat seal strength of at least 1 lb_f /inch (175N/m) at a seal bar temperature of about 110°

C. at less than 0.25 seconds using the DTC Heat Seal Strength Method; and

(b) from 0 to 90 percent by weight of at least one polymer selected from the group consisting of a linear copolymer, of ethylene and a C3-C18-alpha-olefin having a density of greater than 0.916 g/cm³ and a melt index of from 0.1 to 10 g/10 minutes, a high-pressure low density polyethylene having a density of from 0.916 to 0.930 g/cm³ and a melt index of from 0.1 to 10 g/10 minutes and ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate from 2.2;

1 to 24;

1 and a melt index of from 0.2 to 10 g/10 minutes; and

(II) at least one layer of a linear low density ethylene-C₃ -C₁₈ -alpha-olefin copolymer having a density of from about 0.916 to about 0.935 and a melt index of from about 0.1 to about 10 g/10 minutes.

3. The process of claim 2 wherein the film structure includes:

(III) at least one layer of a high-pressure polyethylene having a density of from 0.916 to 0.930 g/cm³ and a melt index of from 0.1 to 10 g/10 minutes.