Minnesota Mining and Manufacturing Company

3m Innovative Properties Company

John D Munter

Donald M Lewis

Robert V Heiti

Peter J Silbernagel

David A Wallack

Yuko Yoshida

Andrew John Ouderkirk

William Blake Kolb

Gary Lee Huelsman

Marvin Kammin

Scott D Stenstrom

Norman E Gehrke

Kevin K Kuck

Joseph H Lam

Michael J Brost

An optical body can be formed using cholesteric liquid crystal materials. At least two different coating compositions containing cholesteric liquid crystal material are coated on a substrate. At least a portion of each composition is allowed to interdiffuse to generate a change in pitch along a thickness dimension of the optical body. This optical body can be used, for example, as a reflective polarizer in an optical display.

Cholesteric liquid crystal optical bodies and methods of manufacture

Drying a coated substrate which includes magnetic particles includes a condensing surface spaced from the substrate. This creates a longitudinal gap between the substrate and the condensing surface. Liquid is evaporated from the substrate to create a vapor and the vapor is transported to the condensing surface without requiring applied convection. The vapor is condensed on the condensing surface to create a condensate which is removed from the condensing surface. Removal is performed, using more than gravity, without allowing non-uniformities of the condensate film to occur. The magnetic particles are oriented on the coated substrate by subjecting the coated substrate to a magnetic field created at a location outside of the dryer space.

Coated substrate drying system with magnetic particle orientation

Coated polymeric sheet comprising polymer substrate a cross-linked polymer, wherein the coating is characterized by:

Process of producing magnetic recording tape having textured backcoat

A magnetizable layer can be applied to a flexible backing web by gravure coating at high speeds by independently driving the backing web at a speed that is substantially different from the surface speed of the gravure roll. Especially high coating speeds have been achieved when the gravure roll rotates oppositely to the direction in which the backing web is advancing. In one embodiment, a nip roll presses the backing web against the backup roll, there is a gap between the gravure roll and a backup roll, and an idler roll is positioned downstream of the gap to force the backing web into contact with the gravure roll over a short arc. When that backup roll has a hard surface such as metal, its surface can be machined with precision, and that precision can be maintained in spite of exposure to solvent vapors.

Differential-speed gravure coating of magnetizable layers in the

Magnetic recording medium having an embossed backcoat layer

A wet gravure coating of fine magnetizable particles can be smoothed by a rectangular piece of flexible film that is secured at one end in flat jaws of a clamp to leave its opposite end free to drag against the coating, thus causing the flexible film to form an arc between its secured end and the convergence of the flexible film with the wet coating. The jaws also secure a flat plate which has a straight edge that deflects the arcuate portion of the flexible film toward the coating along a line extending transversely across the full width of the flexible film. The plate can be repositioned during the smoothing to adjust the radius of curvature of the arc in order to correct any defects that may appear in the smoothed coating. When the backing web is wide and is advanced at economically high speeds, the free end of the flexible film can be tensioned so that its trailing edge becomes bowed and in contact with the coating over its full width.

Method and apparatus for smoothing gravure coatings in the manufacture

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Oakdale, MN, United States of America

John D Munter