摘要:
A novel curable polyimide resin of structural formula (1) or (2) is provided wherein R.sup.1 and R.sup.2 are independently substituted or unsubstituted monovalent C.sub.1-10 hydrocarbon groups, R.sup.3 is a divalent C.sub.1-10 organic group, X is a tetravalent organic group containing an aromatic or aliphatic ring, Y is a divalent organic group, Z is a divalent organic group containing an aromatic ring, W is a trivalent organic group containing an aromatic ring, m is an integer of 1 to 3, and n is an integer of at least 1. It can be prepared by reacting a polyimide with a silicon compound. The curable resin forms with a solvent a solution having a low viscosity and shelf stability and cures at relatively low temperatures below 300.degree. C. into coatings having heat resistance, mechanical strength, electrical properties, solvent resistance and substrate adherence. ##STR1##
摘要:
A composition comprising:(i) a crosslinkable thermoplastic resin;(ii) an aliphatic monomeric compound having two or more carbon to carbon double bonds;(iii) an organic peroxide crosslinking agent; and(iv) a linear organopolysiloxane/alpha-olefin copolymer having the following formula: ##STR1## wherein R is a saturated aliphatic or aromatic group and each R is alike or different;a is about 1 to about 1000; andb is about 5 to about 100The composition is useful as coating composition for an electrical conductor.
摘要:
An oil comprising an amino-modified silicone fluid containing an amino group with an amine equivalent of 10,000 to 200,000 g/mol and having a viscosity of 10 to 100,000 centistokes at 25.degree. C. is effective in preventing any electric contact failure in relays, switches, motors, corotrons and similar electric elements.
摘要:
A thermally conductive sheet comprising a metal foil of which at least one side is coated with a graphite powder-containing silicone rubber layer to gain improved thermally conductive efficiency without attended by decrease in thermal conductivity with time and increase in production cost, and further to enable the enhancement of adhesiveness to other materials by easy incorporation of organopolysiloxanes of adhesion-conferring type into the silicone rubber layer, thus showing excellent aptitude for a thermally conductive sheet of full pack mold transistors.
摘要:
Silicone compositions comprising an organopolysiloxane composition and an organic compound capable of coordination with metals are described. Since the organic compound is preferentially adsorbed on a metal surface, the composition is particularly suitable for use in electric or electronic parts to prevent contact failure. A more specific embodiment comprises a diorganopolysiloxane of the average unit formula, R.sub.a SiO.sub.(4-a)/2, wherein each R independently represents an unsubstituted or substituted monovalent hydrocarbon group, and a is a value of from 1.90 to 2.05, a filler, an alkoxysilane or its hydrolyzate, a silylation catalyst made of an organic silicon compound having at least one specific type of group, an organic tin compound, another organosilicon compound capable of reaction with an alcohol in order to stabilize the composition, and an organic compound capable of coordination with metals.
摘要:
Heat curable dielectric compositions are provided comprising blends of silicone polyimide and epoxy resin and an effective amount of an arylonium salt such as a diaryliodoniumhexafluoroantimonate in combination with a free radical generating aromatic compound as a cocatalyst.
摘要:
Thermally resistant materials comprise an elastomer, particulate iron oxide, and at least one other particulate additive selected from the group consisting of aluminum silicate and silicon carbide. The material may be in the form of a self-supporting element or in the form of a coating.
摘要:
A cable which may be used in buildings in concealed areas such as in plenums or in riser shafts includes a core (22) which includes at least one transmission medium each of which is enclosed with a non-halogenated plastic composition of matter. The core is enclosed with a jacket (28) which also is made of a non-halogenated plastic composition. The non-halogenated plastic material of the insulation includes a polyetherimide constituent and an additive system. The additive system includes an antioxidant/thermal stabilizer and a synergistic metal deactivator and may include a lubricant. For the jacket, the plastic material is a composition which may include a siloxane/polyimide copolymer constituent blended with a polyetherimide constituent and an additive system to improve processing and long term aging, or a siloxane/polyimide copolymer constituent with a flame retardant system.
摘要:
A method is disclosed for the preparation of an integral silicone rubber article having an electrically insulating part and an electrically conductive part, in which the adhesive bonding between the two parts is greatly enhanced and each part exhibits a remarkably small permanent compression set. The method comprises the steps of preparing a first cured silicone rubber body from a first silicone rubber composition and then curing a second silicone rubber body in contact with the first cured silicone rubber body under specified conditions while either one of the first and the second silicone rubber composition contains a substantial amount of a carbon black to give conductivity. Both of the two compositions comprises a non-acyl type organic peroxide, e.g., dicumyl peroxide, as a curing agent of the organopolysiloxane. Characteristically, either one or both of the two composition, of which the organopolysiloxane has at least two silicon-bonded vinyl groups in a molecule, comprise, in addition to the above mentioned organic peroxide, a combination of an organohydrogenpolysiloxane and a platinum catalyst so that the composition or compositions are curable in two ways of, one, the peroxide-induced crosslinking and, the other, the platinum-catalyzed addition reaction between the silicon-bonded vinyl groups and silicon-bonded hydrogen atoms.
摘要:
Graft polymers are produced by grafting amine or acyl groups onto the imide groups of silicone polyimides or polyetherimides; the graft polymers can be moulded onto wires and cross-linked by electron beam irradiation to form insulation having improved properties.