Claims
- 1. A method for making a multilayered optical film, comprising:(a) providing at least a first and a second stream of resin; (b) providing a feeder tube plate having a first plurality of conduits, and having a second plurality of conduits interleaved with the first plurality of conduits; (c) feeding the first stream into the first plurality of conduits and the second stream into the second plurality of conduits; (d) providing a slot die for each of the first and second plurality of conduits such that the first and second streams are divided into a plurality of interleaved layers to yield a composite stream; (e) passing the composite stream through an extrusion die to form a multilayer web in which each layer is generally parallel to the major surface of adjacent layers; and (f) heating the first and second streams of resin with at least one axial rod heater that extends along at least one of the first and second plurality of conduits.
- 2. The method of claim 1, further comprising:(g) positioning the at least one axial rod heater proximate the first and second plurality of conduits.
- 3. The method of claim 1, further comprising:(g) positioning the at least one axial rod heater between the first and second plurality of conduits.
- 4. The method of claim 1, further comprising:(g) varying temperature of the at least one axial rod heater in zones along a length of the axial rod heater.
- 5. The method of claim 1, wherein the heating step comprises heating with a plurality of axial rod heaters.
- 6. The method of claim 5, wherein the healing step comprises heating with a first axial rod heater disposed proximate the first plurality of conduits and heating with a second axial rod heater disposed proximate the second plurality of conduits.
- 7. The method of claim 1, further comprising after step (d):(g) passing the composite stream into a multiplier where the composite stream is divided into a plurality of substreams, the multiplier expanding at least one of the substreams in a direction transverse to its direction of flow; and (h) recombining the substreams to increase the number of layers in the composite stream.
- 8. The method of claim 1, further comprising:(g) casting the multilayer web onto a casting roll to form a cast multilayer film.
- 9. The method of claim 8, further comprising:(h) quenching said multilayer web during the casting step.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 09/229,724, filed Jan. 13, 1999, now abandoned which is a continuation-in-part of U.S. patent application Ser. No. 09/006,288 filed on Jan. 13, 1998, now abandoned, and incorporated herein by reference.
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Continuations (1)
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Number |
Date |
Country |
Parent |
09/229724 |
Jan 1999 |
US |
Child |
09/810916 |
|
US |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
09/006288 |
Jan 1998 |
US |
Child |
09/229724 |
|
US |