Multi-layered thermoplastic films and bags with enhanced light transmittance and methods for making the same
AssigneeThe Glad Products Company
InventorMichael G. Borchardt
Life of this patent
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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.
Claims20
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;
- a second 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;
- a first light transmittance in a direction through the first layer and then the second layer;
- and
- a second light transmittance in a direction through the second layer and then the first layer, wherein the first light transmittance is lesser than the second light transmittance.
A thermoplastic bag, comprising:
- a first layer of thermoplastic material, wherein the first layer comprises:
- first and second side walls joined along a bottom edge, a first side edge, and an opposing second side edge;
- a first plurality of alternating thicker ribs and thinner stretched webs;
- and
- a first opacity agent in a first concentration;
- a second layer of thermoplastic material, wherein the first layer comprises:
- first and second side walls joined along a bottom edge, a first side edge, and an opposing second side edge, the second layer being positioned within the first layer;
- a second plurality of alternating thicker ribs and thinner stretched webs;
- and
- a second opacity agent in a second concentration that is less than the first concentration;
- a first light transmittance in a direction through the first layer and then the second layer;
- and
- a second light transmittance in a direction through the second layer and then the first layer, wherein the first light transmittance is lesser than the second light transmittance.
A method of manufacturing a thermoplastic film with enhanced light transmission, comprising:
- extruding a first layer of thermoplastic material having a first concentration of a light-reflecting opacity agent, the first concentration of the light-reflecting opacity agent being between about 4% and about 6%;
- extruding a second layer of thermoplastic material having a second concentration of a light-absorbing opacity agent, the second concentration of the light-absorbing opacity agent in the second layer of thermoplastic material being between 0.25% and 0.75% such that the second layer of thermoplastic material has a cloudy transparent appearance;
- incrementally stretching the first and second layers by passing the first and second layers between one or more pairs of intermeshing rollers;
- and
- discontinuously bonding the first and second layers together.
Dependencies are inferred from the claim text.