Abstract:
The present invention relates to a nonwoven substrate, and specifically to a nonwoven substrate imparted with a three-dimensional image, wherein the three-dimensional nonwoven substrate is particularly suited as a support substrate for a PCB (Printed Circuit Board) and similar application. By the utilization of a hydroentangled, three-dimensionally imaged support substrate impregnated with a durable resinous matrix, PCB's, and similar applications, can be imparted with unique and useful performance properties, to improve structural performance.
Abstract:
A wholly aromatic polyamide (aramid) fiber synthetic paper sheet includes 70-96 wt % of an aramid staple fiber component which includes 30 wt % or more of a para-type aramid staple fibers each having two or more annular projections spaced from each other and having an average ratio R/&ggr; of the largest diameter R of the annular projections to the smallest diameter &ggr; of the annular projection-free portions of the staple fiber, of 1.1 or more, and 4-30 wt % of a binder component, namely a resinous binder and/or heat resistant fibrids.
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.
Abstract:
Biobased cross-linked compositions, methods of fabrication and structures, in particular biobased printed wiring boards using the compositions and methods of making the structures are described. Biobased materials such as lignin, crop oils, wood resins, tannins, and polysaccharides and combinations thereof are cross-linked, preferably using heat, a cross-linking agent, and an initiator. The materials fabricated have suitable properties for printed wiring boards which are made by impregnating a fiberglass or biobased cloth with an admixture of the biobased material, cross-linking agent and initiator which is processed by conventional methods to produce a printed wiring board.
Abstract:
A heat resistant fiber sheet composed of staple fibers consisting of a heat resistant organic high molecular polymer and fibrids consisting of a heat resistant organic high molecular polymer as main components, having excellent heat resistance, dimensional stability to heat, interlaminar peeling strength, electric insulation resistance under a high humidity, etc., and also good resin impregnating property in spite of having a high bulk density, and especially suitable for a base substrates for an electric insulating material and a laminate for an electric circuit, is obtained by setting the amount of the staple fibers occupying in the total amount of the sheet as 40 to 97% by weight and the amount of the fibrids as 3 to 60% by weight and partially softening and/or melting the fibrids so as to act as a binder.
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.
Abstract:
A method and materials for drilling through-holes in printed circuit boards with a drilling tool is disclosed. The method involves the use of a lubricating entry material placed on the top surface of a stack of printed circuit boards and a lubricating backup board placed beneath the bottom surface of the stack of printed circuit boards. The lubricating entry material has a core with skins attached on both sides by a lubricant/adhesive. Similarly, the backup board has a core with skins attached on both sides by a lubricant/adhesive. The skins are hard enough to support the top and bottom surfaces of the printed circuit boards and thereby reduce burring at the entry point and exit point of the through-hole. The lubricant/adhesive coats the drilling tool during the drilling operation to reduce friction and thereby reduce the temperature of the drilling tool.
Abstract:
A pre-preg substrate, having a low dielectric constant and containing a substantially uniformly distributed hollow-glass-microsphere filler, and method for making the same. The pre-preg substrate is treated with impregnation and lamination techniques to form a laminate with a low dielectric constant, and good mechanical and electrical properties, suitable as a base material for surface mounted devices in high performance circuits. Improved pre-pregs for making high performance circuit boards and for making surface mounted integrated circuits. Improved high performance circuit boards for making surface mounted integrated circuits.
Abstract:
An electrical substrate material is presented comprising a thermosetting matrix of polybutadiene or polyisoprene and a co-curable second resin distinct from the first resin. A peroxide cure initiator and/or crosslinking agent may optionally be added. The presence of a very high surface area particulate filler, preferably fumed silica, is also preferred, in that its presence results in a prepreg which has very little tackiness and can therefore be easily handled by operators. This low tackiness feature allows for the use of conventional automated layup processing, including foil cladding, using one or more known roll laminators. While the prepreg of this invention is tack-free enough to be handled relatively easily by hand, it is also tacky enough to be tacked to itself using a roll laminator (e.g., nip roller) at room temperature. The composition of this invention is particularly well suited for making electrical circuit substrates for microwave and digital circuits, typically in the form of the thermosetting composition being laminated onto one or both opposed surfaces to a metal conductive foil such as copper.
Abstract:
A method of preparing an adhesive composite is provided where a fluoropolymer having nodes and interconnected fibrils with a void volume formed from the node and interconnected fibril structure is at least partially filled with a paste formed from a thermoset or thermoplastic adhesive and a particulate vapor phase formed inorganic filler having uniform surface curvature, sufficient adhesive and filler are present to provide a composite having between about 5 to about 40 volume percent polymeric substrate, 10-95 volume percent adhesive and filler imbibed within the voids of said substrate and 5 to 85 volume percent inorganic filler is contained within the composite. In the composite, the ratio of mean flow pore size to largest particle size is at least above 0.7; or the ratio of mean flow pore size to average particle size is greater than 1.5; or the ratio of minimum pore size to average particle size is at least above 0.8; or the ratio of minimum pore size to largest particle size is at least above 0.4.