Method of producing a lamellar polymeric body

• US 5,316,703 A
• Filed: 01/19/1993
• Issued: 05/31/1994
• Est. Priority Date: 01/22/1991
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Schrenk, Walter J.
• Primary Examiner(s): Thurlow, Jeffery
• Application Number:
  US08/005,267
• Time in Patent Office: 497 Days
• Field of Search: 264/171, 264/1.9, 264/75, 264/1.3, 264/245, 264/1.6, 425/131.1, 425/133.5, 425/462, 425/132
• US Class Current: 264/1.34
• CPC Class Codes: B29C 48/00 Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor extrusion blow-moulding B29C49/04
• CPC Class Codes: B29C 48/07 Flat, e.g. panels
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/16 Articles comprising two or more components, e.g. co-extruded layers
• CPC Class Codes: B29C 48/304 specially adapted for bringing together components, e.g. melts within the die
• CPC Class Codes: B29C 70/585 incorporation of light reflecting filler, e.g. lamellae to obtain pearlescent effet partially embedding reflective elements into the surface of or support B29D11/00615
• CPC Class Codes: B29D 11/00 Producing optical elements, e.g. lenses or prisms grinding or polishing of optical elements B24B; constructional form of optical elements G02B; optical parts of spectacles G02C7/00
• CPC Class Codes: B29K 2995/0031 Refractive
• CPC Class Codes: B32B 2250/42 Alternating layers, e.g. ABAB(C), AABBAABB(C)
• CPC Class Codes: B32B 2307/416 Reflective
• CPC Class Codes: B32B 2307/724 Permeability to gases, adsorption
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 3/18 characterised by an internal layer formed of separate pieces of material which are juxtaposed side-by-side B32B5/02 takes precedence
• CPC Class Codes: B32B 3/22 of spaced pieces not used
• CPC Class Codes: G02B 5/287 comprising at least one layer of organic material
• CPC Class Codes: G02B 5/3008 comprising dielectric particles, e.g. birefringent crystals embedded in a matrix
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture

Abstract

A method for the production of a lamellar reflective polymeric body is provided and includes the steps of providing a first stream of a first heat plastified polymeric material and a second stream of a second heat plastified polymeric material, and encapsulating discrete portions of the first polymeric material in the second polymeric material by coextruding the polymeric materials to form a plurality of ribbon-like layers of the first polymeric material within a matrix of the second polymeric material to form the reflective polymeric body. The layers of the first polymeric material are arranged to have their major interfaces aligned substantially parallel to the major surfaces of the body such that at least 30% of light incident on the body is reflected. The ribbon-like layers may be further divided into a series of platelet-like layers to produce layers which are discontinuous in all major planar dimensions by passing the ribbon-like layers through a reciprocating feed plate or valve.

Claims

1. A method for the production of a lamellar reflective polymeric body comprising the steps of:

providing a first stream of a first heat plastified polymeric material and a second stream of a second heat plastified polymeric material,

encapsulating discrete portions of said first polymeric material in said second polymeric material by coextruding said polymeric materials to form a plurality of ribbon-like layers of said first polymeric material within a matrix of said second polymeric material, thereby forming said reflective polymeric body, which ribbon-like layers are substantially continuous in a first plane parallel to one of the major surfaces of said body and discontinuous in a second plane transverse to said first plane,

and wherein said layers of said first polymeric material have their major interfaces aligned substantially parallel to the major surfaces of said body such that at least 30% of light incident on said body is reflected, the individual layers of said first polymeric material in said body, and those portions of said second polymeric material sandwiched between said individual layers of said first polymeric material, having an optical thickness of not more than 0.09 micrometers or not less than 0.45 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

2. The method of claim 1 wherein said ribbon-like layers are further divided into a series of platelet-like layers to produce layers which are discontinuous in all major planar dimensions.

3. The method of claim 2 wherein said step of dividing said ribbon-like layers into platelet-like layers is accomplished by passing said ribbon-like layers through a reciprocating valve.

4. The method of claim 1 wherein said second polymeric material is an elastomer.

5. The method of claim 1 wherein said first polymeric material is a gas barrier material.

6. The method of claim 1 in which said first polymeric material is polymethyl methacrylate and said second polymeric material is polystyrene.

7. The method of claim 1 in which a fluid is present at a plurality of said major interfaces of said first and second polymeric materials.

8. The method of claim 1 in which said polymeric body is thermoformable.

9. A method for the production of a lamellar reflective polymeric body comprising the steps of:

providing a first stream of a first heat plastified polymeric material and a second stream of a second heat plastified polymeric material,

coextruding said polymeric materials to form alternating layers of said first and second polymeric materials,

encapsulating individual ones of said alternating layers of said first and second polymeric materials in a third polymeric material to form a plurality of discontinuous ribbon-like elements of said alternating layers of said first and second polymeric materials within a matrix of said third polymeric material, thereby forming said reflective polymeric body,

and wherein said alternating layers of said first and second polymeric materials have their major interfaces aligned substantially parallel to the major surfaces of said body such that at least 30% of light incident on said body is reflected, the individual layers of said first and second polymeric materials having optical thicknesses of not more than 0.09 micrometers or not less than 0.45 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

10. The method of claim 9 wherein said ribbon-like elements are further divided into a series of platelet-like elements to produce elements which are discontinuous in all major planar dimensions.

11. The method claim 9 wherein said step of dividing said ribbon-like elements into platelet-like elements is accomplished by passing said ribbon-like elements through a reciprocating valve.

12. The method of claim 9 is which said third polymeric material is elastomeric.

13. The method of claim 9 in which said polymeric body of thermoformable.

14. A method for the production of a lamellar reflective polymeric body comprising the steps of:

providing a first stream of a first heat plastified polymeric material and a second stream of a second heat plastified polymeric material,

feeding alternating slugs of said first and second polymeric materials to a flow passage,

forming said alternating slugs into discontinuous alternating layers of said first and second polymeric materials,

encapsulating individual ones of said alternating layers of said first and second polymeric materials in a third polymeric material to form a plurality of discontinuous ribbon-like elements of said alternating layers of said first and second polymeric materials within a matrix of said third polymeric material, thereby forming said reflective polymeric body,

and wherein said alternating layers of said first and second polymeric materials have their major interfaces aligned substantially parallel to the major surfaces of said body such that at least 30% of light incident on said body is reflected, the individual layers of said first and second polymeric materials having optical thicknesses of not more than 0.09 micrometers or not less than 0.45 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

15. The method of claim 14 wherein the step of feeding alternating slugs of said first and second polymeric materials to a flow passage is accomplished by passing said first and second polymeric materials through a reciprocating valve.

16. The method of claim 15 wherein the frequency of reciprocation of said valve is controlled to control the size of said alternating layers.

17. A method for the production of a lamellar reflective polymeric body comprising the steps of:

providing a first stream of a first heat plastified polymeric material and a second stream of a second heat plastified polymeric material,

encapsulating discrete portions of said first polymeric material in said second polymeric material by coextruding said polymeric materials to form a plurality of ribbon-like layers of said first polymeric material within a matrix of said second polymeric material, thereby forming said reflective polymeric body, which ribbon-like layers are substantially continuous in a first plane parallel to one of the major surfaces of said body and discontinuous in a second plane transverse to said first plane,

and wherein said layers of said first polymeric material have their major interfaces aligned substantially parallel to the major surfaces of said body such that at least 30% of light incident on said body is reflected, the individual layers of said first polymeric material in said body, and those portions of said second polymeric material sandwiched between said individual layers of said first polymeric material, having an optical thickness of between 0.09 micrometers and 0.45 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

18. The method of claim 17 wherein said ribbon-like layers are further divided into a series of platelet-like layers to produce layers which are discontinuous in all major planar dimensions.

19. The method of claim 17 wherein said step of dividing said ribbon-like layers into platelet-like layers is accomplished by passing said ribbon-like layers through a reciprocating valve.

20. The method of claim 17 wherein said second polymeric material is an elastomer.

21. The method of claim 17 wherein said first polymeric material is a gas barrier material.

22. The method of claim 17 in which said first polymeric materials is polymethyl methacrylate and said second polymeric material is polystyrene.

23. The method of claim 17 in which a fluid is present at a plurality of said major interfaces of said first and second polymeric materials.

24. The method of claim 17 in which said polymeric body is thermoformable.

25. The method for the production of a lamellar reflective polymeric body comprising the steps of:

providing a first stream of a first heat plastified polymeric material and a second stream of a second heat plastified polymeric material,

coextruding said polymeric materials to form alternating layers of said first and second polymeric materials,

encapsulating individual ones of said alternating layers of said first and second polymeric materials in a third polymeric material to form a plurality of discontinuous ribbon-like elements of said alternating layers of said first and second polymeric materials within a matrix of said third polymeric material, thereby forming said reflective polymeric body,

and wherein said alternating layers of said first and second polymeric materials have their major interfaces aligned substantially parallel to the major surfaces of said body such that at least 30% of light incident on said body is reflected, the individual layers of said first and second polymeric materials having optical thicknesses of between 0.09 micrometers and 0.45 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

26. The method of claim 25 wherein said ribbon-like elements are further divided into a series of platelet-like elements to produce elements which are discontinuous in all major planar dimensions.

27. The method of claim 25 wherein said step of dividing said ribbon-like elements into platelet-like elements is accomplished by passing said ribbon-like elements through a reciprocating views.

28. The method of claim 25 in which said third polymeric material is elastomeric.

29. The method of claim 25 in which said polymeric body is thermoformable.

30. A method for the production of a lamellar reflective polymeric body comprising the steps of:

providing a first stream of a first heat plastified polymeric material and a second stream of a second heat plastified polymeric material,

feeding alternating slugs of said first and second polymeric materials to a flow passage,

forming said alternating slugs into discontinuous alternating layers of said first and second polymeric materials,

encapsulating individual ones of said alternating layers of said first and second polymeric materials in a third polymeric material to form a plurality of discontinuous ribbon-like elements of said alternating layers of said first and second polymeric materials within a matrix of said third polymeric material, thereby forming said reflective polymeric body,

and wherein said alternating layers of said first and second polymeric materials have their major interfaces aligned substantially parallel to the major surfaces of said body such that at least 30% of light incident on said body is reflected, the individual layers of said first and second polymeric materials having optical thicknesses of between 0.09 micrometers and 0.45 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

31. The method of claim 30 wherein the step of feeding alternating slugs of said first and second polymeric materials to a flow passage is accomplished by passing said first and second polymeric materials through a reciprocating valve.

32. The method of claim 31 wherein the frequency of reciprocation of said valve is controlled to control the size of said alternating layers.