Ahlstrom Filtration, Inc.

John S Baumgardner

Merle W Barclay

Mark D Loewen

A mold release liner for a heated pressure mold for making products such as printed circuit boards is preferably made without polymer films or chemical release agents utilizing two or more wet-laid fiber layers of cellulose or cellulose derivative fibers (such as wood, cotton, cellulose acetate, or rayon fibers, or mixtures of these). The first layer has a sufficiently low density so that it acts as a cushion and absorbs deformation when used as a release liner in the mold (typically it has a thickness of between 8-250 mils, most desirably 40-90 mils, and a basis weight of about 25-350 pounds per ream, most desirably 130-160 pounds per ream). A second layer is of much higher density than the first layer and readily releases from the molds, for example comprising condenser tissue or a similar product, having a thickness of between 0.5-10 mils and a basis weight of 4-50 pounds per ream of 500 sheets. The first and second layers are in face-to-face engagement with each other, and may be adhesively laminated together with sheet, spray, liquid, or powder adhesive. A third layer, substantially like the second layer but on the opposite side of the first face, may also be provided.

Release liners for production of molded products

A single-layer blood separation medium for separating erythrocytes from whole blood and made of a composite including glass microfibers, cellulose fibers, and synthetic textile fibers, having enhanced tensile strength and lower absorptive capacity compared to binderless glass microfiber sheet. The mean bulk density of the glass microfiber component is less than 0.1 g/cm.sup.3, and is typicaly about 0.05 g/cm.sup.3.

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Aspers, PA, United States of America

John S Baumgardner