Transparent paper and method of making same
AssigneeAppleton Papers Inc.
InventorPauline Ozoemena Ukpabi
Life of this patent
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Abstract
The invention teaches a novel paper substrate having a transparent field of a dense array of a plurality of laser-formed microperforations. The resultant paper can be useful as a replacement for glassine paper, and can be useful in secure documents. The transparent field is integral to the paper substrate and can be formed by laser techniques surprisingly resulting in a transparent field retaining acceptable strength characteristics after lasing. The transparent field acts as a self authentication device.
Claims25
A paper substrate having a transparent field, the transparent field comprising an array of a plurality of laser-formed microperforations separated by a land area, the array of microperforations having a density rate of at least 1200 microperforations per square centimeter, the land area separating adjacent microperforations being at least 50 microns and not exceeding 600 microns.
A paper substrate having a transparent field, the transparent field comprising an array of a plurality of laser-formed microperforations separated by a land area, the array of microperforations having a density rate of at least 1200 microperforation per square centimeter, the percent transmittance of the transparent field being at least 70% as measured by ASTM test method D1726-03.
A paper substrate having a semitransparent watermark field, the semitransparent watermark field comprising an array of a plurality of laser formed partial ablation separated by raised land areas, the array of partial ablations having a density rate of at least 1200 partial ablations per square centimeter.
Dependencies are inferred from the claim text.