Polymeric reflective bodies with multiple layer types

• US 5,126,880 A
• Filed: 12/18/1990
• Issued: 06/30/1992
• Est. Priority Date: 12/18/1990
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Wheatley, John A., Schrenk, Walter J.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): NGUYEN, THONG Q
• Application Number:
  US07/629,520
• Time in Patent Office: 560 Days
• Field of Search: 350/163-166, 428/423.3-480, 428/34, 428/195-220, 359/577-590, 359/900
• US Class Current: 359/587
• CPC Class Codes: B32B 2307/416 Reflective
• CPC Class Codes: B32B 2307/418 Refractive
• CPC Class Codes: B32B 2551/08 Mirrors
• CPC Class Codes: B32B 27/06 as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a layer of a particular substance B32B9/045; next to a bituminous or tarry layer B32B11/046; next to a water setting substance layer B32B13/12; next to a metal layer B32B15/08; next to a glass layer B32B17/10; next to a layer formed of natural mineral fibres or particles B32B19/045; next to a wood layer B32B21/08; next to a cellulosic plastic layer B32B23/08; next to a natural or synthetic rubber layer B32B25/08
• CPC Class Codes: B32B 7/023 Optical properties
• CPC Class Codes: G02B 5/0841 comprising organic materials, e.g. polymers
• CPC Class Codes: G02B 5/287 comprising at least one layer of organic material
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]

Abstract

A multilayered, highly reflective polymeric body comprising at least two types of optical layers which is thermoformable and capable of being fabricated into films, sheets and a variety of parts while maintaining a uniform reflective appearance is provided. The reflective polymeric body includes at least first and second diverse polymeric materials having a sufficient number of layers of the first and second polymeric materials such that at least 30% of light incident on the body is reflected. A portion of the layers have optical thicknesses between 0.09 and 0.45 μm, and the remaining layers have optical thicknesses of not greater than 0.09 μm or not less than 0.45 μm. The first and second polymeric materials differ from each other in refractive index by at least about 0.03.

Claims

1. A reflective polymeric body of at least first and second diverse polymeric materials, the body comprising a sufficient number of layers of said first and second polymeric materials such that at least 30% of light incident on said body is reflected, wherein said first and second Polymeric materials differ from each other in refractive index by at least about 0.03, and wherein said layers of said first and second polymeric materials have optical thicknesses such that P_f ≦

0.5, where

space="preserve" listing-type="equation">P.sub.f =(A-B)/B, and

where P_f is the visual perception factor, A is the peak reflectance from said polymeric body, and B is the baseline reflectance from said polymeric body.

2. The reflective polymeric body of claim 1 wherein a portion of said layers have optical thicknesses between 0.09 and 0.45 μ

m and the remaining layers have optical thicknesses of not greater than 0.09 μ

m or not less than 0.45 μ

m.

3. The reflective polymeric body of claim 2 where there is a gradient in the optical thickness of said layers having an optical thickness of between 0.09 and 0.45 μ

m across the layers.

4. The reflective polymeric body of claim 1 in which said first polymeric material is a polycarbonate and said second polymeric material is a miscible blend of polyvinylidene fluoride and polymethylmethacrylate.

5. The reflective polymeric body of claim 1 in which said first polymeric material is polystyrene and said second polymeric material is a copolymer of ethylene and at least one unsaturated monocarboxylic acid.

6. The reflective polymeric body of claim 1 in which said first polymeric material is polystyrene and said second material is polymethylmethacrylate.

7. The reflective polymeric body of claim 1 in which said first polymeric material is a polycarbonate and said second polymeric material is polymethylmethacrylate.

8. The reflective polymeric body of claim 1 in which said first and second polymeric materials are elastomers.

9. The reflective polymeric body of claim 1 in which said polymeric body is in the form of a sheet having two major exterior surfaces.

10. The reflective polymeric body of claim 9 in which said body includes a protective skin layer on at least one major surface thereof.

11. The reflective polymeric body of claim 1 wherein the portion of said layers having an optical thickness in the range of between 0.09 and 0.45 μ

m is positioned at one of the exterior surfaces of said body, and the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned at the other exterior surface.

12. The reflective polymeric body of claim 1 wherein the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned at the exterior surfaces of said body, and the portion of said layers having an optical thickness between 0.09 and 0.45 μ

m is positioned in the interior of said body.

13. The reflective polymeric body of claim 1 wherein the portion of said layers having an optical thickness between 0.09 and 0.45 μ

m is positioned at the exterior surfaces of said body, and the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned in the interior of said body.

14. The reflective polymeric body of claim 1 including a pigmented layer.

15. A reflective polymeric body of at least first and second diverse polymeric materials, the body comprising a sufficient number of layers of said first and second polymeric materials such that at least 30% of light incident on said body is reflected, with a portion of said layers having an optical thickness of between 0.09 and 0.45 μ

m, with the remaining layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m, wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03, and wherein there is an absence of visibly perceived color reflected from said body.

16. The reflective polymeric body of claim 15 where there is a gradient in the optical thickness of said layers having an optical thickness of between 0.09 and 0.45 μ

m across the layers.

17. The reflective polymeric body of claim 15 in which said first polymeric material is polycarbonate said second polymeric material is a blend of polyvinylidene fluoride and polymethylmethacrylate.

18. The reflective polymeric body of claim 15 in which said first polymeric material is polystyrene and said second polymeric material is a copolymer of ethylene and at least one unsaturated monocarboxylic acid.

19. The reflective polymeric body of claim 15 in which said first polymeric material is polystyrene and said second material is polymethylmethacrylate.

20. The reflective polymeric body of claim 15 in which said first polymeric material is polycarbonate and said second polymeric material is polymethylmethacrylate.

21. The reflective polymeric body of claim 15 in which said polymeric body is in the form of a sheet having two major exterior surfaces.

22. The reflective polymeric body of claim 21 in which said body includes a protective skin layer on at least one major surface thereof.

23. The reflective polymeric body of claim 15 in which the portion of said layers having an optical thickness of between 0.09 and 0.45 μ

m comprises a pair of first and second polymers, and the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m comprises a pair of different first and second polymers.

24. The reflective polymeric body of claim 15 wherein the portion of said layers having an optical thickness in the range of between 0.09 and 0.45 μ

m is positioned at one of the exterior surfaces of said body, and the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned at the other exterior surface.

25. The reflective polymeric body of claim 15 wherein the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned at the exterior surfaces of said body, and the portion of said layers having an optical thickness between 0.09 and 0.45 μ

m is positioned in the interior of said body.

26. The reflective polymeric body of claim 15 wherein the portion of said layers having an optical thickness between 0.09 and 0.45 μ

m is positioned at the exterior surfaces of said body, and the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned in the interior of said body.

27. The reflective polymeric body of claim 15 including a pigmented layer.

28. A reflective polymeric body of at least first and second diverse polymeric materials, the body comprising a sufficient number of layers of said first and second polymeric materials such that at least 30% of light incident on said body is reflected, wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03, and wherein said layers of said first and second polymeric materials have optical thicknesses such that the Munsell chroma saturation value of light reflected from said body is /3 or less.

29. The reflective polymeric body of claim 28 wherein a portion of said layers have optical thicknesses between 0.09 and 0.45 μ

m and the remaining layers have optical thicknesses of not greater than 0.09 μ

m or not less than 0.45 μ

m.

30. The reflective polymeric body of claim 28 where there is a gradient in the optical thickness of said layers having an optical thickness of between 0.09 and 0.45 μ

m across the layers.

31. The reflective polymeric body of claim 28 in which said first polymeric material is a polycarbonate said second polymeric material is a blend of polyvinylidene fluoride and polymethylmethacrylate.

32. The reflective polymeric body of claim 28 in which said first polymeric material is polystyrene and said second polymeric material is a copolymer of ethylene and at least one unsaturated monocarboxylic acid.

33. The reflective polymeric body of claim 28 in which said first polymeric material is polystyrene and said second material is polymethylmethacrylate.

34. The reflective polymeric body of claim 28 in which said first polymeric material is a polycarbonate and said second polymeric material is polymethylmethacrylate.

35. The reflective polymeric body of claim 28 in which said polymeric body is in the form of a sheet having two major exterior surfaces.

36. The reflective polymeric body of claim 35 in which said body includes a protective skin layer on at least one major surface thereof.

37. The reflective polymeric body of claim 28 wherein the portion of said layers having an optical thickness in the range of between 0.09 and 0.45 μ

m is positioned at one of the exterior surfaces of said body, and the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned at the other exterior surface.

38. The reflective polymeric body of claim 28 wherein the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned at the exterior surfaces of said body, and the portion of said layers having an optical thickness between 0.09 and 0.45 μ

m is positioned in the interior of said body.

39. The reflective polymeric body of claim 28 wherein the portion of said layers having an optical thickness between 0.09 and 0.45 μ

m is positioned at the exterior surfaces of said body, and the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned in the interior of said body.

40. A reflective polymeric article having at least first and second major surfaces, said article comprising at least first and second diverse polymeric materials, the body comprising a sufficient number of layers of said first and second polymeric materials such that at least 30% of light incident on said body is reflected, wherein a portion of said layers have optical thicknesses between 0.09 and 0.45 μ

m and the remaining layers have optical thicknesses of not greater than 0.09 μ

m or not less than 0.45 μ

m, wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03, and wherein said article includes a pigmented layer.

41. The reflective polymeric article of claim 40 wherein the portion of said layers having an optical thickness in the range of between 0.09 and 0.45 μ

m is positioned at one of the exterior surfaces of said body, the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned in the interior of said body and said pigmented layer is positioned at the other exterior surface.

42. The reflective polymeric article of claim 40 wherein the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned at the exterior of said body, the portion of said layers having an optical thickness between 0.09 and 0.45 μ

m is positioned in the interior of said body and said pigmented layer is positioned at the other exterior surface.

43. The reflective polymeric article of claim 40 wherein the portion of said layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m is positioned at the exterior surfaces of said body, said pigmented layer is positioned in the interior of said body, and portions of said layers having an optical thickness between 0.09 and 0.45 μ

m are positioned adjacent said pigmented layer on both sides thereof.

44. The reflective polymeric article of claim 40 wherein the portion of said layers having an optical thickness of between 0.09 and 0.45 μ

m is positioned at the exterior surfaces of said body, said pigmented layer is positioned in the interior of said body, and portions of said layers having an optical thickness not greater than 0.09 μ

m or not less than 0.45 μ

m are positioned adjacent said pigmented layer on both sides thereof.

45. A birefringent light polarizer which reflects light anisotropically, comprising multiple layers of at least first and second diverse polymeric materials, a portion of said layers having an optical thickness of between 0.09 and 0.45 μ

m, with the remaining layers having an optical thickness of not greater than 0.09 μ

m or not less than 0.45 μ

m, wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03 in one plane of the polarizer.