Multilayer plastic film

Patent metadata

Field	Value
Publication number	US-9469443-B2
Application number	US-88182510-A
Country	US
Kind code	B2
Filing date	Sep 14, 2010
Priority date	Sep 14, 2010
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

A thermoplastic bag suitable for use as a liner for a garbage canister or trash receptacle may be made from a multi-layered thermoplastic web material. The multi-layer web material may include a first layer and a second layer adjacent to the first layer. Under typical conditions, the layers may tend to block or adhere together to remain in their adjacent position. However, the layers may delaminate and separate from each other when sufficient forces are applied. Delamination of the layers allows the layers to move with respect to each other when the force is applied. The delaminating of the layers absorbs energy which may increase tear and puncture resistance.

First claim

What is claimed is:

1. A flexible thermoplastic bag comprising:
a first sidewall of pliable thermoplastic material;
a second sidewall of pliable thermoplastic material joined to the first sidewall along a first side edge, a second side edge and a closed bottom edge, the first and second sidewalls un-joined along their respective top edges to provide an opening for accessing the interior volume;
wherein the first sidewall is a multi-layer film including a first layer bonded via co-extrusion to an adjacent second layer and a composition of the thermoplastic material of the first layer and a composition of the thermoplastic material of the second layer are selected such that the co-extrusion bond between the first and second layers at least partially breaks, when subjected to stress consistent with use as a liner for a trash receptacle, causing the first and second layers to at least partially delaminate from each other; and
wherein the second layer is of a different material than the first layer;
wherein the edges of the first and second layers of the multi-layer film are heat sealed together thereby preventing separation of the edges of the first and second layers.

2. The bag of claim 1 , wherein the first sidewall includes a third layer.

3. The bag of claim 1 , wherein the bag further comprises tie flaps extending from the top edges of the first and second sidewalls.

4. The bag of claim 1 , wherein the co-extrusion bond between the first and second layers at least partially breaks when objects are dropped into the interior volume of the bag.

5. The bag of claim 1 , wherein the materials of the first and second layers are dissimilar thermoplastic materials such that when co-extruded a weak co-extrusion bond is formed.

6. The bag of claim 1 , wherein the at least partial breaking of the co-extrusion bond absorbs energy associated with the stress thereby increasing a resistance of the flexible thermoplastic bag to tear due to the stress.

7. A flexible thermoplastic bag comprising:
a first sidewall of pliable thermoplastic material;
a second sidewall of pliable thermoplastic material joined to the first sidewall along a first side edge, a second side edge and a closed, folded bottom edge, the first and second sidewalls un-joined along their respective top edges to provide an opening for accessing the interior volume;
the first sidewall and second sidewall forming a hem, the hem having a hem seal and a draw tape within the hem;
wherein the thermoplastic material of the first and second sidewalls consists essentially of a thermoplastic, multilayer laminate film comprising:
a first layer of thermoplastic material; and
an adjacent second layer of thermoplastic material, wherein the first and second layers are co-extruded and the first and second layers of the multi-layer laminate film are selected so that the first and second layers at least partially delaminate from each other upon the application of a force consistent with use as a liner for a trash receptacle due to a co-extrusion bond between the first and second layers at least partially breaking; and wherein the first and second layers are of different materials and are selected from the group of materials consisting of high density polyethylene, low density polyethylene, medium density polyethylene, linear low density polyethylene, very low density polyethylene, polypropylene, ethylene vinyl acetate, nylon, polyester, and ethylene vinyl alcohol;
wherein the edges of the first and second layers of the multi-layer laminate film are heat sealed together thereby preventing separation of the edges of the first and second layers.

8. The film of claim 7 , wherein the first layer comprises linear low density polyethylene and the second layer comprises very low density polyethylene.

9. The film of claim 7 , wherein the first layer comprises linear low density polyethylene and the second layer comprises medium density polyethylene.

10. The film of claim 7 , wherein the first layer comprises very low density polyethylene and the second layer comprises medium density polyethylene.

11. The bag of claim 7 , wherein at least one of the first and second layers include an anti-blocking agent.

12. The bag of claim 7 , wherein the co-extrusion bond between the first and second layers at least partially breaks when objects are dropped into the interior volume of the bag.

13. The bag of claim 7 , wherein the materials of the first and second layers are dissimilar thermoplastic materials such that when co-extruded a weak co-extrusion bond is formed.

14. The bag of claim 7 , wherein the at least partial breaking of the co-extrusion bond absorbs energy associated with the force thereby increasing a resistance of the flexible thermoplastic bag to tear due to the force.

15. A bag comprising:
first and second sidewalls comprising a thermoplastic multi-layer film, the multi-layer thermoplastic film comprising:
a first layer,
a second layer, and
a continuous co-extrusion bond securing the first layer directly to the second layer, the continuous co-extrusion bond having a tailored strength such that co-extrusion bond at least partially breaks causing at least partial delamination of the first layer and the second layer when objects are dropped into an interior volume of the bag;

a first side heat seal securing the first and second sidewalls together, the first side heat seal securing first side edges of the first and second layers together thereby preventing the first side edges of the first and second layers from delaminating from each other; and
a second side heat seal securing the first and second sidewalls together, the second side heat seal securing second side edges of the first and second layers together thereby preventing the second side edges of the first and second layers from delaminating from each other.

16. The bag as recited in claim 15 , further comprising:
a hem;
a hem seal securing top edges of the first and second layers together thereby preventing the top edges of the first and second layers from delaminating from each other; and
a drawtape positioned within the hem.

17. The bag as recited in claim 15 , wherein materials of the first and second layers are dissimilar thermoplastic materials that form a weak co-extrusion bond when co-extruded together.

18. The bag as recited in claim 17 , wherein: the first layer comprises a polyethylene material and the second layer comprises polypropylene or polystyrene.

19. The bag as recited in claim 15 , wherein the multi-layer thermoplastic film comprises:
a third layer; and
a second co-extrusion bond securing the first layer directly to the third layer, the second co-extrusion bond having a tailored strength such that second co-extrusion bond prevents delamination of the first layer and the third layer during normal use of the bag.

20. The bag as recited in claim 19 , the multi-layer thermoplastic film comprises:
a fourth layer; and
a third co-extrusion bond securing the second layer directly to the fourth layer, the third co-extrusion bond having a tailored strength such that third co-extrusion bond prevents delamination of the second layer and the fourth layer during normal use of the bag.

Assignees

• Hoying David J
• Broering Shaun T
• Waldron Matthew W
• Peck Daniel C
• Turner Robert H
• Glad Products Co

Inventors

• Hoying David J
• Broering Shaun T
• Waldron Matthew W
• Peck Daniel C
• Turner Robert H

Classifications

• Y10T428/3192

  Next to vinyl or vinylidene chloride polymer · CPC title

• Y10T428/31797

  Next to addition polymer from unsaturated monomers · CPC title

• Y10T428/31746

  Polymer of monoethylenically unsaturated hydrocarbon · CPC title

• Y10T428/31736

  Next to polyester · CPC title

• B65D33/165

  Flexible elongated elements integral with or attached to bags or sacks (draw closures B65D33/28); Fastening thereof to the bag before closing · CPC title