Thick/very thin multilayer reflective polymeric body

• US 5,122,906 A
• Filed: 01/17/1990
• Issued: 06/16/1992
• Est. Priority Date: 06/20/1989
• 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.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): Nguyen, Thong
• Application Number:
  US07/466,168
• Time in Patent Office: 881 Days
• Field of Search: 350/163-167, 425/133.5, 428/220, 428/212-215, 428/423.3-423.7, 428/474.4-480, 356/71, 359/577, 359/884, 359/580-590, 359/483-502
• US Class Current: 359/586
• CPC Class Codes: B32B 2250/40 Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
• CPC Class Codes: B32B 2307/416 Reflective
• CPC Class Codes: B32B 2375/00 Polyureas; Polyurethanes
• CPC Class Codes: B32B 2377/00 Polyamides
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: B32B 27/34 comprising polyamides
• CPC Class Codes: B32B 27/40 comprising polyurethanes
• CPC Class Codes: B32B 33/00 Layered products characterised by particular properties or particular surface features, e.g. particular surface coatings; Layered products designed for particular purposes not covered by another single class
• CPC Class Codes: B32B 7/023 Optical properties
• CPC Class Codes: G02B 1/04 made of organic materials, e.g. plastics G02B1/08 takes precedence
• CPC Class Codes: G02B 1/08 made of polarising materials
• CPC Class Codes: G02B 5/0841 comprising organic materials, e.g. polymers
• CPC Class Codes: G02B 5/0883 with a refractive index gradient rugate filters G02B5/289
• CPC Class Codes: G02B 5/26 Reflecting filters G02B5/28 takes precedence
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers
• CPC Class Codes: H01L 31/056 the light-reflecting means being of the back surface reflector [BSR] type
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]

Abstract

A multilayered reflective body 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 of a sufficient number of alternating layers of the first and second polymeric materials such that at least 30% of the light incident on the body is reflected. A substantial majority of the individual layers of the body have an optical thickness of not more than 0.09 micrometers or not less than 0.45 micrometers, with at least one of the individual layers having an optical thickness of not more than 0.09 micrometers, and adjacent layers of 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 first and second diverse polymeric materials, the body comprising a sufficient number of alternating layers of said first and second polymeric materials such that at least 30% of light incident on said body is reflected, where the intensity of the reflected light is governed by the equation R=(kr)/1+(k-1)r×

100, where R is the amount of reflected light (%), k is the number of thick and very thin film layers, and r=((N₁ -N₂)/(N₁ +N₂))², and N₁ and N₂ are the refractive indices of said polymeric materials at each layer interface, a substantial majority of the individual layers of said body having an optical thickness of not more than 0.09 micrometers or not less than 0.45 micrometers, with at least one of said individual layers having an optical thickness of not more than 0.09 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

2. A reflective polymeric body of at least first and second diverse polymeric materials, the body comprising a sufficient number of alternating layers of said first and second polymeric materials such that at least 30% of light incident on said body is reflected, but such that essentially no visibly perceived iridescence is reflected, a substantial majority of the individual layers of said body having an optical thickness of not more than 0.09 micrometers or not less than 0.45 micrometers, with at least one of said individual layers having an optical thickness of not more than 0.09 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

3. The reflective polymeric body of claim 2 in which said first polymeric material is polycarbonate and said second polymeric material is polymethyl methacrylate.

4. The reflective polymeric body of claim 2 in which said first polymeric material is a rigid polyurethane and said second polymeric material is polymethyl methacrylate.

5. The reflective polymeric body of claim 2 in which said first polymeric material is a flexible polyurethane and said second polymeric material is a polyether amide.

6. The reflective polymeric body of claim 2 in which said body comprises at least 500 layers.

7. The reflective polymeric body of claim 2 in which said polymeric body is thermoformable.

8. The reflective polymeric body of claim 2 including a coloring agent incorporated into at least one layer of said polymeric body.

9. The reflective polymeric body of claim 8 in which said coloring agent is selected from a group consisting of pigments and dyes.

10. The reflective polymeric body of claim 9 in which said coloring agent is incorporated into at least one surface layer of said polymeric body.

11. The reflective polymeric body of claim 9 in which said coloring agent is incorporated into at least one interior layer of said polymeric body.

12. The reflective polymeric body of claim 2 in which a least one surface layer has a brushed or roughened surface.

13. The reflective polymeric body of claim 2 in which at least one surface layer has been etched to provide a matte or pewter finish.

14. The reflective polymeric body of claim 2 in which at least one surface layer has been embossed.

15. The reflective polymeric body of claim 2 in which said first and second polymeric materials are elastomers.

16. The reflective polymeric body of claim 2 in which a substantial majority of the individual layers of said first polymeric material have an optical thickness of at least 0.45 micrometers and a substantial majority of the individual layers of said second polymeric material have an optical thickness of 0.09 micrometers or less.

17. The reflective polymeric body of claim 16 in which at least 75% of said individual layers of said first polymeric material have an optical thickness of at least 0.45 micrometers.

18. The reflective polymeric body of claim 16 in which at least 75% of said individual layers of said second polymeric material have an optical thickness of 0.09 micrometers or less.

19. The reflective polymeric body of claim 2 in which said body is extruded as a profile.

20. The reflective polymeric body of claim 19 in which said body is in the form of a tube.

21. The reflective polymeric body of claim 2 in which said body is post formed into a profile.

22. The reflective polymeric body of claim 2 in which said body is a blow-molded container.

23. The reflective polymeric body of claim 2 in which said polymeric body is in the form of a sheet having two major surface.

24. The reflective polymeric body of claim 23 in which said body includes a permanent protective skin layer on at least one major surface thereof.

25. The reflective polymeric body of claim 2 which includes a barrier layer as an exterior layer of said body.

26. The reflective polymeric body of claim 2 in which said polymeric body includes first, second, and third diverse polymeric materials of alternating layers in a pattern ABCBA.

27. The reflective polymeric body of claim 26 in which said first polymeric material is polystyrene, said second polymeric material is a styrene hydroxy ethylacrylate copolymer, and said third polymeric material is polymethyl methacrylate.

28. The reflective polymeric body of claim 2 which includes a barrier layer as an interior layer of said body.

29. A reflective polymeric film of at least first and second diverse polymeric materials, the film comprising a sufficient number of alternating layers of said first and second polymeric materials such that at least 30% of light incident on said film is reflected, where the intensity of the reflected light is governed by the equation R=(kr)/(1+(k-1)r)×

100, where R is the amount of reflected light (%), k is the number of thick and very thin film layers, and, r=((N₁ -N₂)/(N₁ +N₂))², and N₁ and N₂ are the refractive indices of said polymeric materials at each layer interface, a substantial majority of the individual layers of said film having an optical thickness of not more than 0.09 micrometers or not less than 0.45 micrometers, with at least one of said individual layers having an optical thickness of not more than 0.09 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

30. A mirror like polymeric article having at least first and second major surfaces, said article comprising a sufficient number of alternating layers of first and second polymeric materials such that at least 30% of light incident on said body is reflected, a substantial majority of the individual layers of said body having an optical thickness of not more than 0.09 micrometers or not less than 0.45 micrometers, with at least one of said individual layers having an optical thickness of not more than 0.09 micrometers, wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03, and wherein one of said major surfaces includes a light absorbent layer.

31. A mirror like polymeric article having at least first and second major surfaces, said article comprising a sufficient number of alternating layers of first and second polymeric materials such that at least 30% of light incident on said body is reflected, and at least one interior light absorbing layer, a substantial majority of the individual layers of said body having an optical thickness of not more than 0.09 micrometers or not less than 0.45 micrometers, with at least one of said individual layers having an optical thickness of not more than 0.09 micrometers, and wherein said first and second polymeric materials differ from each other in refractive index by at least about 0.03.

32. A birefringent light polarizer which reflects light anisotropically, comprising multiple layers of at least first and second diverse polymeric materials, a substantial majority of the individual layers of said polarizer having an optical thickness of not more than 0.09 micrometers or not less than 0.45 micrometers, with at least one of said individual layers having an optical thickness of not more than 0.09 micrometers, and 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.

33. The birefringent light polarizer of claim 32 in which the difference in refractive index between said first and second polymeric materials is caused by stretching said materials in a uniaxial direction to orient said polymeric materials.