Retroreflective sheet material

• US 3,934,065 A
• Filed: 08/01/1973
• Issued: 01/20/1976
• Est. Priority Date: 08/01/1973
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Tung, Chi Fang
• Primary Examiner(s): Kendall, Ralph S.
• Assistant Examiner(s): Buffalow, Edith R.
• Application Number:
  US05/384,703
• Time in Patent Office: 902 Days
• Field of Search: 161/1, 161/3.5, 161/DIG. 5, 161/410, 161/4, 161/45, 161/89, 161/92, 161/91, 428/256, 428/241, 428/245, 428/402, 40/135, 40/134, 40/130 B, 350/105, 350/109
• US Class Current: 428/76
• CPC Class Codes: E01F 9/654 in the form of three-dimensional bodies, e.g. cones; capable of assuming three-dimensional form, e.g. by inflation or erection to form a geometric body
• CPC Class Codes: E01F 9/688 Free-standing bodies
• CPC Class Codes: G02B 5/128 transparent spheres being embedded in matrix
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 428/239 Complete cover or casing
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

A new retroreflective sheet material is taught that comprises a light-transmissive retroreflective open web of filaments that are individually encased by a monolayer of minute retroreflective microspheres, the web being ensheathed within an envelope that comprises two overlaid sheets joined together around the edge of the envelope, at least one of the sheets being transparent.

Claims

1. Retroreflective sheet material capable of reflecting under wet or dry conditions comprising (a) an envelope that comprises two overlaid sheets joined together around the edge of the envelope, at least one of the sheets being transparent, and (b) at least one light-transmissive retroreflective open web of filaments ensheathed within the envelope, the filaments being encased around their whole circumference at least over those parts of their length that define open spaces of the web by a monolayer of minute retroreflective microspheres.

2. Sheet material of claim 1 in which the filaments are flexible and the microspheres are partially embedded in and held to the filaments by a layer of elastomeric binder material coated on the filaments.

3. Retroreflective sheet material capable of reflecting under wet or dry conditions comprising (a) an envelope that comprises two supple overlaid polymer-based sheets joined together around the edge of the envelope, at least one of the sheets being transparent, and (b) at least one light-transmissive retroreflective open-mesh fabric ensheathed within the envelope, the fabric comprising interwoven filaments that are encased around their whole circumference over those parts of their length that define the open meshes of the fabric by a monolayer of minute retroreflective microspheres partially embedded in a layer of binder material that is coated on the filaments after the filaments have been woven into a fabric;

the embedded surfaces of the microspheres being covered by specularly reflective means.

4. Sheet material of claim 3 in which both sheets of the envelope are transparent.

5. Sheet material of claim 3 in which the sheets of the envelope comprise a vinyl chloride polymer.

6. Retroreflective sheet material of claim 3 in which the spaces between the microsphere-encased filaments occupy between 20 and 80 percent of the area occupied by the sheeting.

7. Retroreflective sheet material capable of reflecting under wet or dry conditions comprising (a) an envelope that comprises two transparent supple overlaid polymer-based sheets heat-sealed together around the edge of the envelope, and (b) an open-mesh fabric ensheathed within the envelope, the fabric comprising interwoven flexible filaments that are encased around their whole circumference over those parts of their length that define the open meshes of the fabric by a monolayer of minute retroreflective microspheres partially embedded in a layer of elastomeric material that is coated on the filaments after the filaments have been woven into a fabric;

the embedded surfaces of the microspheres being covered by specularly reflective means, and the spaces between the microsphere-encased filaments occupying between 20 and 80 percent of the area occupied by the fabric.