Method of preparing retroreflective sheeting
AssigneeMinnesota Mining and Manufacturing Company
InventorWilliam A. Wood
Life of this patent
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Abstract
Retroreflective sheeting having improved resistance to delamination is prepared by imparting a grid pattern to a monolayer of glass spheres having a light reflecting layer thereon, applying a sphere binder layer over the grid pattern imposed on the monolayer of glass spheres so as to adhere to the reflective layer on the monolayer of glass spheres, and pressure consolidating the resulting composite against a clear, protective overlay film, wherein the overlay film bonds to the sphere binder layer in the grooves formed by the grid pattern.
Claims9
A method of preparing retroreflective sheeting comprising the steps of:
- a. temporarily adhering a monolayer of glass spheres of substantially uniform diameter to a release sheet;
- b. covering the exposed surfaces of the glass spheres with a light reflecting material to form a light reflecting layer on said monolayer of glass spheres;
- c. imparting a grid pattern to the monolayer of glass spheres on the light reflecting layer thereof such that the depth of the grid pattern is at least the radius of the glass spheres remaining in said monolayer;
- d. applying a sphere binder layer over said grid pattern imposed on the monolayer of glass spheres, said sphere binder layer having sufficient plastic flow to adhere to the light reflecting layer on said monolayer of spheres but not to the opposing surfaces of said spheres;
- e. removing said release sheet to leave a distributed sphere covered sheet;
- and
- f. pressure consolidating said distributed sphere covered sheet against a clear, protective overlay film, said overlay film bonding to said sphere binder layer in the grooves defined by the grid pattern.
Dependencies are inferred from the claim text.