Methods and apparatus for embossing a precision optical pattern in a resinous sheet or laminate
US4601861A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 1984 |
| Grant date | Jul 22, 1986 |
| Priority date | — |
| Expiry date | Aug 10, 2004 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB32B2307/416
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Disclosed herein are an improved method and apparatus for continuously embossing a repeating pattern of precise detail, in particular, cube-corner type reflector elements, on one surface of a single sheet or on one surface of a laminate of transparent thermoplastic materials, to form retroreflective sheeting. A continuous embossing tool in the form of a flexible thin metal belt or cylinder has on its outer surface an embossing pattern which is the reverse of the precision optical pattern to be formed. The embossing tool is continously moved at a predetermined speed along a closed course through a heating station where the temperature of a portion of the embossing tool is raised to be above the glass transition temperature of the sheeting or laminate and a cooling station where the heated portion of the embossing tool is cooled while in a relatively planar condition to be below that glass transition temperature. The sheeting is continuously moved at the predetermined speed from a supply thereof into engagement with the embossing pattern on the tool and is pressed thereagainst continuously at a plurality of pressure points sequentially spaced along the heating station, with the one s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.