Methods and apparatus for generating interfacial surfaces

• US 5,094,793 A
• Filed: 12/21/1990
• Issued: 03/10/1992
• Est. Priority Date: 12/21/1990
• Status: Expired due to Term

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Gosen, Daniel J., Schrenk, Walter J., Shastri, Ranganath K., Ayres, Ralph E.
• Primary Examiner(s): Thurlow, Jeffery
• Application Number:
  US07/632,448
• Time in Patent Office: 445 Days
• Field of Search: 264/171, 425/131.1, 425/133.5, 425/462
• US Class Current: 264/173.15
• CPC Class Codes: B01F 25/4323 using elements provided with a plurality of channels or using a plurality of tubes which can either be placed between common spaces or collectors
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/21 the layers being joined at their surfaces
• CPC Class Codes: B29C 48/307 specially adapted for bringing together components, e.g. melts within the die
• CPC Class Codes: B29C 48/71 for layer multiplication extrusion of multi-component articles B29C48/16

Abstract

Method and apparatus for generating interfacial surfaces in a fluid mass which:

(a) divide a first stream of the fluid mass into a plurality of branch streams, redirect or reposition the branch streams, expand and contract the branch streams in a symmetrical fashion, and recombine the branch streams to form a second stream of the fluid mass; or

(b) divide a first stream of the fluid mass into a plurality of branch streams, redirect or reposition the branch streams, recombine the branch streams to form a second stream of the fluid mass, and expand and contract the second stream in a symmetrical fashion.

Claims

1. A method for generating interfacial surfaces within a first composite stream comprised of discrete overlapping layers of polymeric material, of which at least a pair of such discrete overlapping layers define a generally planar layer interface therebetween which lies generally in an x-z plane of an x-y-z coordinate system, wherein the z-axis is taken as extending in the general direction of flow of the first composite stream, the x-axis extends transversely of the first composite stream and defines a transverse dimension of the layer interface, and the y-axis extends generally perpendicularly away from the planar layer interface in the thickness direction of the pair of discrete overlapping layers, said method comprising the steps of:

dividing the first composite stream into a plurality of branch streams along the x-axis, such that the pair of discrete overlapping layers and the generally planar layer interface defined therebetween are distributed among two or more of the branch streams;

repositioning at least the two or more branch streams among which the pair of discrete overlapping layers and the generally planar layer interface therebetween were distributed along both of the x- and y-axes as the branch streams flow along the z-axis;

individually symmetrically expanding a transverse dimension of at least the two or more branch streams along the x-axis;

individually symmetrically contracting the thickness of at least the two or more branch streams along the y-axis; and

recombining the branch streams in overlapping relationship to form a second composite stream which comprises a greater number of discrete overlapping layers of polymeric material than the first composite stream.

2. A method as defined in claim 1, wherein the branch streams are expanded uniformly.

3. A method as defined in claim 1, wherein the branch streams are contracted uniformly.

4. A method as defined in claim 1, wherein the first composite stream is divided into a plurality of branch streams of substantially identical rectangular or square cross-section.

5. A method as defined in claim 1, wherein the step of repositioning the branch streams is accomplished without significantly altering their cross-sections.

6. A method as defined in claim 1, wherein the step of repositioning the branch streams includes divergently displacing the branch streams along the y-axis and convergently displacing the branch streams along the x-axis.

7. A method as defined in claim 1, wherein the first composite stream is divided into an even number of branch streams.

8. A method as defined in claim 1, wherein at least some of the discrete, overlapping layers in the first composite stream are of a generally planar, substantially continuous nature and span the first composite stream along the x-axis.

9. A method as defined in claim 8, wherein the branch streams are recombined whereby the second composite stream comprises a greater number of discrete, generally planar and substantially continuous layers than the first composite stream.

17. A method of making a multilayered plastic article, comprising the steps of:

forming a second composite stream according to the method of claim 1; and

molding the second composite stream into a desired configuration.

10. A method of generating interfacial surfaces within a first composite stream from a feedblock, the stream being comprised of discrete overlapping layers of polymeric material of which at least a pair of such discrete overlapping layers define a generally planar layer interface therebetween which lies generally in an x-z plane of an x-y-z coordinate system, wherein the z-axis is taken as extending in the general direction of flow of the first composite stream, the x-axis extends transversely of the first composite stream and defines a transverse dimension of the layer interface, and the y-axis extends generally perpendicularly away from the planar layer interface in the thickness direction of the pair of discrete overlapping layers, wherein said method consists essentially of:

dividing the first composite stream into a plurality of branch streams along the x-axis, such that the pair of discrete overlapping layers and the generally planar layer interface defined therebetween are distributed among two or more of the branch streams;

repositioning at least the two or more branch streams among which the pair of discrete overlapping layers and the generally planar layer interface therebetween were distributed along the y-axis as the branch stream flow along the z-axis;

recombining the branch streams in overlapping relationship to form a second composite stream which comprises a greater number of discrete overlapping layers of polymeric material than the first composite stream;

symmetrically expanding a transverse dimension of the second composite stream along the x-axis; and

symmetrically contracting the thickness of the second composite stream in the y-direction.

11. A method as defined in claim 10, wherein the first composite stream is divided into a plurality of branch streams of substantially identical rectangular or square cross-section.

12. A method as defined in claim 10, wherein the step of repositioning the branch streams is accomplished without significantly altering their cross-sections.

13. A method as defined in claim 10, wherein the step of repositioning the branch streams includes divergently displacing the branch streams along the y-axis and convergently displacing the branch streams along the x-axis.

14. A method as defined in claim 10, wherein the first composite stream is divided into an even number of branch streams.

15. A method as defined in claim 10, wherein at least some of the discrete, overlapping layers in the first composite stream are of a generally planar, substantially continuous nature and span the first composite stream along the x-axis.

16. A method as defined in claim 15, wherein the second composite stream after being expanded and contracted comprises a greater number of discrete, generally planar and substantially continuous layers than the first composite stream.

18. A method of making a multilayered plastic article, comprising the steps of:

forming, expanding and contracting a second composite stream according to the method of claim 12; and

molding the second composite stream into a desired configuration.

19. An apparatus for generating interfacial surfaces within a first composite stream comprised of discrete overlapping layers of polymeric material, of which at least a pair of such discrete overlapping layers define a generally planar layer interface therebetween which lies generally in an x-z plane of an x-y-z coordinate system, wherein the z-axis is taken as extending in the general direction of flow of the first composite stream, the x-axis extends transversely of the first composite stream and defines a transverse dimension of the layer interface, and the y-axis extends generally perpendicularly away from the planar layer interface in the thickness direction of the pair of discrete overlapping layers, wherein said apparatus comprises:

dividing means for dividing the first composite stream into a plurality of branch streams along the x-axis, such that the pair of discrete overlapping layers and the generally planar layer interface defined therebetween are distributed among two or more of the branch streams;

a plurality of first conduits for repositioning the branch streams along both the x-axis and the y-axis;

a plurality of second conduits in fluid communication with the first conduits, with each second conduit having a progressively greater transverse dimension along the x-axis from an inlet opening to an outlet port thereof, the inlet opening being positioned centrally in the apparatus;

a plurality of third conduits in fluid communication with the second conduits, with each third conduit having a dimension in the y-direction which becomes progressively lesser from an inlet opening to an outlet port thereof; and

means for recombining the branch streams from the third conduits to form a second composite stream which comprises a greater number of discrete overlapping layers of polymeric material than the first composite stream.

20. An apparatus for generating interfacial surfaces within a first composite stream comprised of discrete overlapping layers of polymeric material, of which at least a pair of such discrete overlapping layers define a generally planar layer interface therebetween which lies generally in an x-z plane of an x-y-z coordinate system, wherein the z-axis is taken as extending in the general direction of flow of the first composite stream, the x-axis extends transversely of the first composite stream and defines a transverse dimension of the layer interface, and the y-axis extends generally perpendicularly away from the planar layer interface in the thickness direction of the pair of discrete overlapping layers, wherein said apparatus comprises:

dividing means for dividing the first composite stream into a plurality of branch streams along the x-axis, such that the pair of discrete overlapping layers and the generally planar layer interface defined therebetween are distributed among two or more of the branch streams;

a plurality of first conduits for repositioning the branch streams along both the x-axis and the y-axis; and

a conduit wherein the branch streams are recombined and symmetrically expanded and contracted, said conduit defining a tetrahedral cavity through which the recombined branch streams flow, the cavity being formed by the intersection of sides of the conduit in the general form of four truncated isosceles or equilateral triangles.