Printed circuit boards, adhesives

MAJOR PRODUCT APPLICATIONS rubber pads, liquid encapsulants, underfills, printed circuit boards, adhesives, greases, hquid coatings, aerosol sprays... 

Bare die and other chip devices are attached with electrically conductive or nonconductive adhesives to ceramic substrates having defined circuit patterns produced by thin-film vapor deposition and photoetching of metals or by screen-printing and firing of thick-film pastes. With recent advancements in fine-line printed-circuit boards, adhesives are also finding use in attaching bare die to PWBs, a technology known as chip-on-board (COB). 

Printed circuit boards manufacture is aided by the use of KMnO. Alkaline permanganate solution is used to remove resin smeared on the interior hole wall of multilayered printed circuit boards. Additionally the hole wall is etched, resulting in a surface with excellent adhesion characteristics, for electrodeless copper (250). The alkaline permanganate etchback system containing >60 g/L KMnO and 40-80 g/L NaOH at 70—80°C, is effective for difunctional, tetrafiinctional, and polyimide resin substrates, where the level of etchback is direcdy proportional to the immersion time (10—20 min) (251). 

Because the heat distortion temperature of cured epoxy resins (qv) increases with the functionality of the curing agents, pyromellitic dianhydride is used to cross-link epoxy resins for elevated temperature service. The dianhydride may be added as a dispersion of micropulverized powder in liquid epoxy resin or as a glycol adduct (158). Such epoxies may be used as an insulating layer in printed circuit boards to improve heat resistance (159). Other uses include inhibition of corrosion (160,161), hot melt traffic paints (162), azo pigments (163), adhesives (164), and photoresist compounds (165). 

Phenohc/adhesives adhesives / sealants / gaskets abrasives and break pad binders printed circuit boards stmctural composites /laminates Metal/glass binders metal oxide binders retroreflective coatings glass optical coatings Hard copy printing inks toners... 

A.dhesiveslCements Sealants j Coatings. Excellent adhesives of high strength and high oil resistance can be prepared using nitnle mbber (25). Many references have discussed the use of nitnle mbber—phenoHc and nitnle mbber—epoxy adhesives for printed circuit boards. 

Printed circuit board component such as laminates, conformal coatings, solder masks, masking tapes, component attachment adhesives, vibration dampers and photoresists. 

Fig. 6. Photomicrograph illustrating the assembling of the thin film sensor array with the printed circuit board, a. sensor array, b. counter electrode, c. pacer, d. channel for conductive adhesive with conducting pad of PCB, e. inlet hole for conductive adhesive,/ outlet hole for conductive adhesive, g. bonding pads...

JP 05125345 (Japanese) 1993 Poly(vinyl butyral) blend adhesive composition for flexible printed circuit boards Ube Industries, Japan H Inoe, S Takabayashi, T Muramatsu, T Funakoshi Formulated resins having good flexibility and heat resistance are useful adhesives for polyimide/Cu foil laminated circuit boards Maleimide-terminated siloxane-imide block copolymers were formulated with poly(vinyl butyral) and melamine resins to give adhesive compositions. 

JP 05311144 (Japanese) 1993 Heat-resistant adhesive compositions containing polyimide-siloxane block copolymers Ube Industries, Japan H Inoe, S Takabayashi, T Funakoshi, K Sonoyana Useful for Cu-clad laminates of printed circuit boards and tape-automated bonding with good flexibility and heat resistance Formulated compositions containing siloxane-imide block copolymers made from aromatic tetracarboxylic acids and aromatic diamines and aminosiloxanes... 

Furukawa N,Yuasa M.Omoro F,YamadaY (1996) Adhesive properties of siloxane-mod-ified polyimides and application for multi-layer printed circuit boards. J Adhes 59 1,281... 

Brominated epoxy resins are the reaction product of epichlorohydrin and brominated bisphenol A. They are primarily used in applications where ignition resistance is a requirement, such as printed-circuit boards and other products that need to be flame-retardant. Tetrabromobisphenol A is the largest flame retardant in terms of commercial use at present. It is used in an estimated 95 percent of all flame-retardant printed wiring boards and is used in many flame-retardant surface-mounted adhesives.2 It is manufactured by several producers and is priced as a commodity product. 

Nitto Denko Corporation primarily manufactures industrial adhesive tapes for the electronics, automotive, health care, packaging and construction industries. The company produces industrial, electronic and functional products. Industrial products include double-coated adhesive tapes, masking tapes surface protective materials, sealing materials and label printing systems. Electronics products include LCD-related items general and advanced device resins printed circuit boards and semiconductor package adhesive sheets. Functional products include medical items such as transdermal therapeutic patches polymer separation membranes used for water purification and treatment and plastic engineering products such as information equipment and porous film materials used in cars, electronics, and home appliances. Nitto Denko America, Inc., an optoelectronics subsidiary, manufactures semiconductor... 

The 150 kilotons of ammoninm chloride that are prodnced per year are mostly nsed as fertilizer and, in order of importance, for solid electrolytes in dry cell batteries, a component of quarrying explosives, hardeners for formaldehyde-based adhesives, one component of etching solutions in the manufacture of printed circuit boards, and a component, along with zinc chloride, of fluxes in tin and zinc plating. 

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