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US 5,389,324 AGranted
Layer thickness gradient control in multilayer polymeric bodies
AssigneeThe Dow Chemical Company
InventorsRay A. Lewis, David M. Wisniewski, Ravi Ramanathan, Walter J. Schrenk
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Abstract
Methods and apparatus for generating, and then precisely controlling, layer thickness gradients in multilayered polymeric reflective bodies are provided. The creation of such gradients is useful in tailoring multilayer bodies to reflect and/or transmit desired wavelengths of light. Both thermal and mechanical methods, as well as combinations thereof, are used.
Claims28
A method for generating a layer thickness gradient within a multilayer polymeric body comprising the steps of:
- providing separate streams of at least first and second heat plastified polymeric materials;
- dividing each of said streams into a plurality of first substreams and a plurality of second substreams;
- controlling the respective flow rates of said polymeric materials in said substreams to provide a differential in the volume of polymeric materials flowing through each of said substreams;
- and
- combining said substreams into a composite stream having said plurality of first and second substreams interdigitated into overlapping generally planar layers with substantially parallel layer interfaces to form said multilayer body, said layers formed from the substream having the greater volumetric flow rate being thicker than said layers formed from the substream having the lesser volumetric flow rate to form a gradient in layer thicknesses.
2 more elements
A method for generating a layer thickness gradient within a multilayer polymeric body comprising the steps of:
- providing separate streams of at least first and second heat plastified polymeric materials;
- dividing each of said streams into a plurality of first substreams and a plurality of second substreams and then combining said plurality of first and second substreams into a first composite stream having said first and second substreams interdigitated into overlapping generally planar layers having substantially parallel layer interfaces;
- separating said composite stream along an axis parallel to said planar layers into a plurality of branch streams;
- manipulating at least one of said branch streams to increase the number of layers in said branch stream and thereby decrease their thicknesses;
- and
- recombining said branch streams into a second composite stream having overlapping generally planar layers having an increased number of substantially parallel layer interfaces to form said body, said layers having a gradient in thicknesses resulting from said manipulation of at least one of said branch streams.
3 more elements
A method for generating a layer thickness gradient within a multilayer polymeric body comprising the steps of:
- providing separate streams of at least first and second heat plastified polymeric materials;
- dividing each of said streams into a plurality of first substreams and a plurality of second substreams and then combining said plurality of first and second substreams into a first composite stream having said first and second substreams interdigitated into overlapping generally planar layers having substantially parallel layer interfaces;
- separating said composite stream along an axis perpendicular to said planar layers into a plurality of branch streams;
- manipulating at least one of said branch streams to increase the number of layers in said branch stream and thereby decrease their thicknesses;
- and
- recombining said branch streams into a second composite stream having overlapping generally planar layers having an increased number of substantially parallel layer interfaces to form said body, said layers having a gradient in thicknesses resulting from said manipulation of at least one of said branch streams.
3 more elements
An apparatus for generating a layer thickness gradient within a multilayer polymeric body comprising:
- means for providing at least first and second streams of heat plastified polymeric materials;
- means for dividing said at least first and second streams into a plurality of first substreams and a plurality of second substreams;
- means for controlling the respective flow rates of said polymeric materials in said plurality of first and second substreams to provide a differential in the volume of polymeric materials flowing through each of said substreams;
- and
- means for combining said substreams into a composite stream having said plurality of first and second substreams interdigitated into overlapping generally planar layers with substantially parallel layer interfaces to form said multilayer body, said layers formed from the substream having the greater volumetric flow rate being thicker than said layers formed from the substream having the lesser volumetric flow rate to form a gradient in layer thicknesses.
2 more elements
An apparatus for generating a layer thickness gradient within a multilayer polymeric body comprising:
- means for providing at least first and second streams of heat plastified polymeric materials;
- means for dividing said at least first and second streams into a plurality of first substreams and a plurality of second substreams;
- means for combining said substreams into a composite stream having said plurality of first and second substreams interdigitated into overlapping generally planar layers with substantially parallel layer interfaces to form said multilayer body;
- means for separating said composite stream into a plurality of branch streams;
- means for manipulating at least one of said branch streams to increase the number of layers in said branch stream and thereby decrease their thicknesses;
- and
- means for recombining said branch streams into a second composite stream having overlapping generally planar layers having an increased number of substantially parallel layer interfaces to form said body, said layers having a gradient in thicknesses resulting from said manipulation of at least one of said branch streams.
4 more elements
Dependencies are inferred from the claim text.