Multilayer polymeric reflective bodies for decorative and security applications

• US 5,234,729 A
• Filed: 02/27/1992
• Issued: 08/10/1993
• Est. Priority Date: 02/27/1992
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Wisniewski, David M., Wheatley, John A., Schrenk, Walter J.
• Primary Examiner(s): Ryan, Patrick J.
• Assistant Examiner(s): Lee, Cathy K.
• Application Number:
  US07/842,864
• Time in Patent Office: 530 Days
• Field of Search: 428/30, 428/130, 428/155, 428/176, 428/167, 428/212, 428/213, 428/215, 428/220, 428/409, 428/411.1, 428/204, 428/206, 428/76, 428/332, 428/916, 428/913.3
• US Class Current: 428/30
• CPC Class Codes: B29C 43/30 Making multilayered or multicoloured articles B29C43/26 takes precedence
• CPC Class Codes: B29C 48/001 Combinations of extrusion moulding with other shaping operations
• CPC Class Codes: B29C 48/0017 combined with blow-moulding or thermoforming
• CPC Class Codes: B29C 48/0019 combined with shaping by flattening, folding or bending
• CPC Class Codes: B29C 48/07 Flat, e.g. panels
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/12 Articles with an irregular circumference when viewed in cross-section, e.g. window profiles
• CPC Class Codes: B29C 48/13 Articles with a cross-section varying in the longitudinal direction, e.g. corrugated pipes
• 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 48/908 characterised by calibrator surface, e.g. structure or holes for lubrication, cooling or venting
• CPC Class Codes: B29C 48/914 cooling drums
• CPC Class Codes: B29C 48/9155 Pressure rollers
• 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 2995/003 Reflective
• CPC Class Codes: B29L 2009/00 Layered products
• CPC Class Codes: G02B 5/287 comprising at least one layer of organic material
• CPC Class Codes: Y10T 428/24264 Particular fold structure [e.g., beveled, etc.]
• CPC Class Codes: Y10T 428/24471 Crackled, crazed or slit
• CPC Class Codes: Y10T 428/2457 Parallel ribs and/or grooves
• CPC Class Codes: Y10T 428/24645 : with folds in parallel planes
• CPC Class Codes: Y10T 428/24942 : including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/2495 : Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/31504 : Composite [nonstructural laminate]

Abstract

A multilayered reflective polymeric body of alternating layers of polymers wherein at least a portion of the layers are in a folded-over relationship is provided along with a coextrusion apparatus and method of preparing the multilayer polymeric body. The reflective polymeric body includes at least first and second diverse polymeric materials having a sufficient number of alternating layers of the first and second polymeric materials such that a portion of the light incident on the body is reflected. The first and second polymeric materials differ from each other in refractive index by at least about 0.03. The reflective body is thermoformable and may be fabricated into wall panels, dishware, decorative trims, and the like, and may also find use in security applications such as credit cards, credit card emblems, or on currency.

Claims

1. A multilayer reflective polymeric body of at least first and second diverse generally transparent polymeric materials, arranged in a sufficient number of alternating layers of said first and second polymeric materials such that at least 30% of the 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 at least a portion of said reflective polymeric body includes at least some of said alternating layers in a folded-over relationship.

2. The multilayer reflective polymeric body of claim 1 wherein said folded-over relationship of said layers produces striations on portions of said body.

3. The multilayer reflective polymeric body of claim 1 wherein said body comprises at least 500 layers.

4. The multilayer reflective polymeric body of claim 1 wherein said body is thermoformable.

5. The multilayer reflective polymeric body of claim 1 including a coloring agent incorporated into at least one layer of said polymeric body.

6. The multilayer reflective polymeric body of claim 1 wherein a substantial majority of said alternating layers have optical thicknesses of at least 0.45 μ

m or less than 0.09 μ

m.

7. The multilayer reflective polymeric body of claim 1 wherein a portion of said alternating layers have optical thicknesses between 0.09 μ

m 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.

8. The multilayer reflective polymeric body of claim 1 wherein the portion of said layers in said folded-over relationship have optical thicknesses of at least 0.45 μ

m or less than 0.09 μ

m.

9. The multilayer reflective polymeric body of claim 1 wherein a portion of said layers in said folded-over relationship 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.

10. The multilayer reflective polymeric body of claim 1 wherein a substantial majority of said alternating layers have optical thicknesses of greater than 0.09 μ

m and less than 0.45 μ

m.

11. The multilayer reflective polymeric body of claim 1 wherein a substantial majority of the individual layers of said first polymeric material in said folded-over relationship have an optical thickness of at least 0.45 μ

m and a substantial majority of the individual layers of said second polymeric material in said folded-over relationship have an optical thickness of 0.09 μ

m or less.

12. The multilayer reflective polymeric body of claim 1 in which said body is extruded as a profile.

13. The multilayer reflective polymeric body of claim 1 in which said body is post formed into a profile.

14. The multilayer reflective polymeric body of claim 1 wherein said polymeric body is in the form of a sheet having two major surfaces.

15. The multilayer reflective polymeric body of claim 1 wherein said polymeric body includes a protective skin layer on at least one major surface thereof.