US 6,258,203 B1 · Base webs for printed circuit board production using the foam process and acrylic fibers

Abstract

A printed circuit board is made from at least one non-woven sheet or web layer comprising at least 50% by weight acrylic fibers, with any balance substantially electrically non-conductive fibers, filler, and binder. The sheet or web is preferably made by the foam process, and may contain 60-80% straight polyacrylonitrile fibers and 40-20% fibrillated (pulp) ones. The web or sheet is preferably compressed by thermal calendering so that it has a density of about 0.1-1 grams per cubic centimeter; and the web or sheet may have a basis weight of between about 20-120 grams per square meter. The web or sheet may also have a 1-40% of substantially electrically non-conductive organic or inorganic binder, or may be substantially binder free. A printed circuit board made using the layers of these non-woven webs or sheets is otherwise conventional, including a pre-preg material, electrically conductive circuit elements, and electronics, and has improved properties compared to woven glass and non-woven aramid products, including improved fiber consolidation, easy board construction, and improved MD/CD ratio and stability.

Claims24

Dependent claims

A method of producing a printed circuit board comprising:

(a) using a foam-laid process for making non-woven fibrous webs to form a non-woven sheet or web comprising at least 50% by weight of a mixture of both fibrillated and straight acrylic fibers, and the balance at least one of substantially electrically non-conductive fibers, filler, and binder;
(b) densifying the sheet or web from (a);
(c) forming a printed circuit board layer using the sheet or web from (b);
(d) combining the layer from (c) with other substantially electrically non-conductive layers;
and
(e) providing electrically conductive circuit elements on or between at least one of the layers from (c).

3 more elements

Dependencies are inferred from the claim text.

Base webs for printed circuit board production using the foam process and acrylic fibers

Life of this patent

Base webs for printed circuit board production using the foam process and acrylic fibers

Life of this patent

Abstract

Claims24