Patent Number: 6,253,442

Title: Retroreflective cube corner sheeting mold and method for making the same

Abstract: A method is disclosed for manufacturing a plurality of laminae for use in a mold suitable for use in forming retroreflective cube corner articles. Each lamina has opposing first and second major surfaces defining therebetween a first reference plane. Each lamina further includes a working surface connecting the first and second major surfaces. The working surface defines a second reference plane substantially parallel to the working surface and perpendicular to the first reference plane and a third reference plane perpendicular to the first reference plane and the second reference plane. The method includes orienting a plurality of laminae to have their respective first reference planes parallel to each other and disposed at a first angle relative to a fixed reference axis. At least two groove sets are formed in the working surface. Each groove set includes at least two parallel adjacent V-shaped grooves in the working surface of the laminae. The at least two groove sets form first, second and third groove surfaces that intersect substantially orthogonally to form a plurality of cube corner elements. Each of the plurality of cube corner elements is preferably located on essentially one of the plurality of lamina. The plurality of laminae can be oriented at a second angle relative to the fixed reference axis prior to forming at least one of the groove sets. A mold according to the present invention and a retroreflective article made therefrom are also disclosed.

Inventors: Benson; Gerald M. (Woodbury, MN), Smith; Kenneth L. (White Bear Lake, MN)

Assignee: 3M Innovative Properties Company

International Classification: B29D 11/00 (20060101); B23P 013/04 ()

Expiration Date: 07/03/2018