Multi-layered thermoplastic films and bags with enhanced light transmittance and methods for making the same

Patent metadata

Field	Value
Publication number	US-10196177-B2
Application number	US-201414508850-A
Country	US
Kind code	B2
Filing date	Oct 7, 2014
Priority date	Nov 16, 2009
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

Implementations described herein include films with maintained or decreased light transmittance despite a reduction in gauge. In particular, one or more implementations include a multi-layer film with each layer having differing opacity agents. The combination of the two different opacity agents in two different layers can have a synergistic effect that provide decreased light transmittance. Indeed, in one or more embodiments a multi-layer film with differing opacity agents in each layer has a decreased light transmittance despite a reduction in gauge and opacity agents.

First claim

I claim:

1. A multi-layer thermoplastic film comprising:
a first layer of thermoplastic material, the first layer of thermoplastic material comprising a first opacity agent and a first plurality of alternating thicker ribs and thinner stretched webs, wherein a total weight concentration of the first opacity agent in the first layer of thermoplastic material is between 0.25% and 1.0%, wherein the first plurality of alternating thicker ribs and thinner stretched webs are either parallel or perpendicular to a predominate direction of orientation of the first layer of thermoplastic material;
a second layer of thermoplastic material intermittently secured directly to the first layer of thermoplastic material, the second layer of thermoplastic material comprising a second opacity agent and a second plurality of alternating thicker ribs and thinner stretched webs, wherein the second plurality of alternating thicker ribs and thinner stretched webs are either parallel or perpendicular to a predominate direction of orientation of the second layer of thermoplastic material;
a first light transmittance in a direction through the first layer and then the second layer at a first location of the multi-layer thermoplastic film; and
a second light transmittance in a direction through the second layer and then the first layer at the first location of the multi-layer thermoplastic film, wherein the first light transmittance is lesser than the second light transmittance.

2. The multi-layer thermoplastic film as recited in claim 1 , wherein:
the first layer comprises a third light transmittance;
the second layer comprises a fourth light transmittance; and
the third light transmittance is less than the fourth light transmittance.

3. The multi-layer thermoplastic film as recited in claim 1 , wherein the first light transmittance is between 3% and 6% smaller than the second light transmittance.

4. The multi-layer thermoplastic film as recited in claim 1 , wherein the first opacity agent comprises a light-reflecting opacity agent and the second opacity agent comprises a light-absorbing opacity agent.

5. The multi-layer thermoplastic film as recited in claim 4 , wherein the second layer of thermoplastic material appears cloudy gray or transparent.

6. The multi-layer thermoplastic film as recited in claim 4 , wherein the first opacity agent comprises a white pigment and the second opacity agent comprises a black pigment.

7. The multi-layer thermoplastic film as recited in claim 1 , wherein:
the first plurality of alternating thicker ribs and thinner webs comprises a first set of thicker ribs and thinner webs extending in a first direction across the first layer and a second set of thicker ribs and thinner webs extending in a second direction across the first layer; and
the second plurality of alternating thicker ribs and thinner webs comprises a third set of thicker ribs and thinner webs extending in the first direction across the second layer and a fourth set of thicker ribs and thinner webs extending in the second direction across the second layer.

8. The multi-layer thermoplastic film as recited in claim 7 , wherein the first direction comprises a machine direction and the second direction comprises a transverse direction.

9. The multi-layer thermoplastic film as recited in claim 1 , further comprising a plurality of bonds securing the first layer to the second layer.

10. The multi-layer thermoplastic film as recited in claim 9 , wherein the plurality of bonds are aligned with and secure thicker ribs of the first layer to thicker ribs of the second layer.

11. The multi-layer thermoplastic film as recited in claim 1 , wherein the multi-layer thermoplastic film is devoid of voiding agents.

12. A multi-layer thermoplastic film comprising:
a first layer of thermoplastic material, the first layer of thermoplastic material comprising a first opacity agent and a first plurality of alternating thicker ribs and thinner stretched webs, wherein the first plurality of alternating thicker ribs and thinner stretched webs are either parallel or perpendicular to a predominate direction of orientation of the first layer of thermoplastic material;
a second layer of thermoplastic material intermittently secured directly to the first layer of thermoplastic material, the second layer of thermoplastic material comprising:
a second opacity agent; and
a second plurality of alternating thicker ribs and thinner stretched webs, wherein the second plurality of alternating thicker ribs and thinner stretched webs are either parallel or perpendicular to a predominate direction of orientation of the second layer of thermoplastic material;

a first average light transmittance across the multi-layer thermoplastic film in a direction through the first layer and then the second layer; and
a second average light transmittance across the multi-layer thermoplastic film in a direction through the second layer and then the first layer, wherein the first average light transmittance is lesser than the second average light transmittance.

13. The multi-layer thermoplastic film as recited in claim 12 , wherein the first light transmittance is between 3% and 6% smaller than the second light transmittance.

14. The multi-layer thermoplastic film as recited in claim 12 , wherein the first opacity agent comprises a light-reflecting opacity agent and the second opacity agent comprises a light-absorbing opacity agent.

15. The multi-layer thermoplastic film as recited in claim 14 , wherein a total weight concentration of the light-absorbing opacity agent in the second layer of thermoplastic material is between 0.25% and 1.0% such that the second layer of thermoplastic material appears cloudy gray or transparent.

16. The multi-layer thermoplastic film as recited in claim 14 , wherein the first opacity agent comprises a white pigment and the second opacity agent comprises a black pigment.

17. The multi-layer thermoplastic film as recited in claim 12 , wherein:
the first plurality of alternating thicker ribs and thinner webs comprises a first set of thicker ribs and thinner webs extending in a first direction across the first layer and a second set of thicker ribs and thinner webs extending in a second direction across the first layer; and
the second plurality of alternating thicker ribs and thinner webs comprises a third set of thicker ribs and thinner webs extending in the first direction across the second layer and a fourth set of thicker ribs and thinner webs extending in the second direction across the second layer.

18. The multi-layer thermoplastic film as recited in claim 17 , wherein the first direction comprises a machine direction and the second direction comprises a transverse direction.

19. The multi-layer thermoplastic film as recited in claim 12 , further comprising a plurality of bonds securing the first layer to the second layer.

20. The multi-layer thermoplastic film as recited in claim 19 , wherein the bonds of the plurality of bonds are aligned with and secure thicker ribs of the first layer to thicker ribs of the second layer.

Assignees

• Glad Products Co

Inventors

• Borchardt Michael G

Classifications

• B32B2307/7163

  Biodegradable · CPC title

• B32B2307/414

  Translucent · CPC title

• B32B3/10

  characterised by a discontinuous layer, i.e. formed of separate pieces of material · CPC title

• B32B2439/46

  Bags · CPC title

• B32B3/28

  characterised by a layer comprising a deformed thin sheet {, i.e. the layer having its entire thickness deformed out of the plane}, e.g. corrugated, crumpled (B32B29/08 takes precedence) · CPC title