Abstract:
An electronic device comprises a housing made of a polycarbonate resin, and a novel double-sided printed circuit board. The printed circuit board has one side embedded in the housing, and the other side exposed to the interior of the housing. A plurality of refractory electronic components are mounted onto one side of the printed circuit board and include a resistor and a capacitor. A plurality of lower refractory electronic components are mounted onto the other side of the housing and include a semiconductor integrated circuit, and a transformer. Preferably, an insulating layer is applied to cover the one side of the printed circuit board and the refractory electronic components. Also, a metal layer is applied to cover the insulating layer and the inner surface of the housing.
Abstract:
A curable composition based on a cycloaliphatic polyepoxide, a polytetramethylene oxide polyol and a photoinitiator; and a circuit board having as a conformal coating thereon, the cured product of the curable composition.
Abstract:
A printed circuit board having electrical components connected thereto in spaced relation is coated with a resin material by immersion in a container of resin material. The flow of resin between the electrical devices and the circuit board is facilitated by the provision of holes through the circuit board in alignment with each electrical component so that the formation of blow-holes is prevented.
Abstract:
Compositions useful as UV curable conformal coatings are mixtures, substantially free of isocyanate condensation catalyst, of the following constituents:(i) a compound having two or more alkenyl or alkynyl groups;(ii) a compound having two or more mercapto groups;(iii) a compound having two or more isocyanate groups; and(iv) a free radical photoinitiator.The composition cures by a secondary mechanism in shadow areas and has a long pot life, for example 8-24 hours.
Abstract:
Ultraviolet curable polymerizable coating system having a built-in secondary curing mechanism is disclosed. The polymerizable coating system is a one component system comprising at least one isocyanate-capped polyether diol and triol, an acrylate or methacrylate reactive diluent, and a polymerization initiator of the photo-initiator type. The coating system is also moisture curable.
Abstract:
A process for applying a polyurethane gel composition for coating and encapsulating the electronic circuitry on a circuit board wherein the said composition consists essentially of an admixture of an elastomeric linear polyesterurethane of high molecular weight; a tetrahydrofuran intermediate monomer solvent and ethylene glycol monoethylether acetate, which composition is preferably sprayed over the object circuitry and onto the related electronic circuit board or other substrate as a vaporized gel of minute viscous globules which simultaneously forms a substantially uniform protective film over the substrate and encapsulates the circuit''s conduit and conduit terminals as well as other protrusions, including elements having sharp points, knife edges and the like. This prime coat is then dried and may be subsequently followed by one or more dip coatings which are formed by immersion of the dried workpiece into a mixture of polymethyl methacrylate with a copolymer of ethyl acrylate/methyl methylacrylate.
Abstract:
A liquid composition for stripping resin coatings such as epoxy embedment or conformal coatings from substrates such as printed circuit boards. The composition is a substantially anhydrous combination of organic liquids comprising on a volume basis above about 60 percent of a halogenated hydrocarbon liquid, a minor amount below 12 percent but above 4 percent of an alcohol and below 5 percent but at least 1 percent of a ketone. The resin coating is contacted with the composition for a period sufficient to loosen and solvate said resin. The removal of the softened resin may be facilitated by brushing.
Abstract:
A method includes steps of forming an inner coating on an object and forming an outer coating in contact with the inner coating. A first solution including metal oxide nanoparticles and a first solvent is applied onto the object. The first solvent is removed to form the inner coating with the metal oxide nanoparticles. A second solution having silicon dioxide nanoparticles and a second solvent is applied onto the object. The second solvent is removed to form the outer coating with the silicon dioxide nanoparticles. The interfacial binding force between the metal oxide nanoparticles and the silicon dioxide nanoparticles is then strengthened, for example, by applying a third solution such as water, ethanol or a mixture thereof to the inner coating and the outer coating.