The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 20, 1998
Filed:
Aug. 09, 1995
John S Baumgardner, Aspers, PA (US);
Merle W Barclay, Mt. Holly Springs, PA (US);
Ahlstrom Filtration Inc., Mt. Holly Springs, PA (US);
Abstract
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.