Abstract: A corona-resistant wire enamel composition is described comprising a polyetherimide resin and from about 1% to about 35% by weight of dispersed alumina particles of a finite size less than about 0.1 micron, the alumina particles being dispersed therein by high shear mixing. A method of providing corona resistant insulations for an electrical conductor employing the above composition and an electrical conductor insulated with a coating of the wire enamel composition are also disclosed.

Abstract: A multi-layer circuit board laminate is disclosed having a controlled thermal coefficient of expansion which is particularly useful in conjunction with leadless components. The subject invention includes incorporating one or more stabilizing metal sheets into a composite multi-layer circuit board laminate assembly. The stabilizing metal sheets function to significantly reduce the circuit board laminate's thermal coefficient of expansion, thereby enabling the laminate to be used in conjunction with leadless electronic components. In addition, a novel method is disclosed for fabricating one embodiment of the subject invention and includes a unique two-step lamination process which permits apertures to be provided in the metal stabilizing layer and allows the bonding epoxy resin to solidify within the apertures, while simultaneously preventing the entrapment of air.

Abstract: A high voltage arc-resistant laminate for printed circuit boards comprising a substrate and metallic foil bonded on one or both surfaces of the substrate. The substrate includes core sheets of cellulosic paper impregnated with a resin formulation comprising an admixture of resin solids including a major amount of phenolic resins, and minor amount of curing agents for the resins, and face sheets of glass fiber cloth impregnated with a resin formulation consisting substantially entirely of brominated aromatic epoxy resin solids, and minor amount of dicyandiamide curing agent and amine catalyst along with, antimony oxide, thixotropic agent, and pigments. Also disclosed is a process for manufacturing the laminate. A high temperature resistant embodiment is also disclosed in which the core sheet resin is brominated aromatic epoxy instead of phenolic resin.

Abstract: A new and improved method for preparing a fire resistant electrical-conductor is disclosed in which a length of a metal core conductor is first wrapped with a mica-impregnated glass tape to form a continuous first layer, and then an outer coat of a heat-curable platinum catalyzed silicone rubber composition is applied around the tape layer which is cured to form a fire resistant insulation for the electrical conductor. The insulated conductors of the invention provide circuit integrity under fire and may be useful in critical circuitry such as fire alarms and elevators.

Abstract: A corona-resistant wire enamel composition is described comprising a polyimide, polyamide, polyester, polyamideimide, polyesterimide, or polyetherimide resin and from about 1% to about 35% by weight of dispersed alumina particles of a finite size less than about 0.1 micron, the alumina particles being dispersed therein by high shear mixing. A method of providing corona resistant one and two-stage insulations for an electrical conductor employing the above compositions and an electrical conductor insulated with a one or two-stage coating of the wire enamel compositions are also disclosed.

Abstract: The subject invention relates to a multi-layer circuit board laminate which includes one or more stabilizing metal sheets for reducing the thermal coefficient of expansion of the laminate. In addition, a novel two-step fabrication method is disclosed which permits apertures to be provided in the metal stabilizing layer and prevents the entrapment of air in those apertures as they are filled with epoxy.A multi-layer circuit board laminate is disclosed having a controlled thermal coefficient of expansion which is particularly useful in conjunction with leadless components. The subject invention includes incorporating one or more stabilizing metal sheets into a composite multi-layer circuit board laminate assembly. The stabilizing metal sheets function to significantly reduce the circuit board laminate's thermal coefficient of expansion, thereby enabling the laminate to be used in conjunction with leadless electronic components.

Abstract: A corona-resistant wire enamel composition is described comprising a polyimide, polyamide, polyester, polyamideimide, polyesterimide, or polyetherimide resin and from about 1% to about 35% by weight of dispersed alumina particles of a finite size less than about 0.1 micron, the alumina particles being dispersed therein by high shear mixing. A method of providing corona resistant one and two-stage insulations for an electrical conductor employing the above compositions and an electrical conductor insulated with a one or two-stage coating of the wire enamel compositions are also disclosed.

Abstract: A method of preparing a novel electromagnetic wave attenuating composition comprising forming a curable film forming coating composition and thereafter dispersing an effective amount of an electrically conductive additive in said curable film forming composition under low shear conditions to form said electromagnetic wave blocking composition.

Abstract: Improved enamels and insulated electrical articles produced therefrom are described. The enamels are composed of solutions of curable resin which have been modified to contain nylon polymer. This polymer facilitates application of the enamel to a metallic conductor so as to produce an especially smooth and desirable insulation coating.

Abstract: Improved thermally-curable adhesive compositions for bonding articles of poly(butylene terephthalate) together or to other articles are disclosed. The adhesive compositions comprise at least one epoxidic prepolymer having two or more epoxy groups, an aromatic halonium complex salt thermal initiator dissolved in a compatibilizing non-epoxidic organic liquid, a copper carboxylate salt cocatalyst, a polyhydric alcohol, and optionally, silica filler. The adhesive compositions when heated, cure to form an adhesive bond between articles of poly(butylene terephthalate) which exhibits a vastly improved bond strength over presently available epoxy adhesive materials.

Abstract: A resist film composed of a water-soluble polyvinyl alcohol, a water-soluble thermosetting polymethylol cross-linking agent and a polyaryl iodonium or sulfonium salt of a complex halogenide as catalyst, when irradiated with ultraviolet light and then heated, or when heated and irradiated with ultraviolet light, under a circuit mask, provides a latent image which is developable by water alone.

Abstract: Electrical coating compositions comprise blended polyesterimides and from 1 to 20 percent by weight of total solids of an ester terminated amide imide. Such compositions provide insulation coatings on electrical conductors which have superior smoothness, even after high speed coating operations.

Abstract: Improved polyetherimide compositions and processes for their production are described. Various polyetherimide derivatives including water-soluble and tri-functional isocyanate cross-linked resins are described. They permit production of water-based enamels and coatable particulates which may be employed in, for example, formulation of insulated electrical conductors.

Abstract: Electrical coating compositions comprise blended polyesterimides and from 1 to 20 percent by weight of total solids of an ester terminated amide imide. Such compositions provide insulation coatings on electrical conductors which have superior smoothness, even after high speed coating operations.

Abstract: A novel coating composition is disclosed that is useful for primary resin based composition. The composition comprises an aqueous aliphatic polyurethane, an anionic surfactant and a carbon containing pigment.

Abstract: A crosslink curable ethylene-propylene rubber composition with improved resistance to heat shock, the cured rubber composition and electrical conductors insulated with said cured rubber composition. The improved rubber composition comprises a combination of ethylene-propylene rubbers of different structural orientation, and antioxidants.

Abstract: The invention relates to polymeric coating compositions which are at least partially soluble in water and are particularly stable.Polyester, polyesterimides, polyesteramides, polyesteramideimides, polyesterhydantoins and polyester urethanes are prepared with free carboxyl or carboxylic acid groups. The carboxylic acid groups are neutralized with amine containing material, at least fifty percent excess amine being used, producing a coating composition which is at least partially soluble in water. The coating compositions are particularly useful as electric insulating coatings or wire enamels which are readily coated on a metallic or other substrate and when cured form coatings having good electrical and physical properties. They are also useful in making laminates, composites, and the like.

Abstract: A resist film composed of a water-soluble polyvinyl alcohol, a water-soluble thermosetting polymethylol cross-linking agent and a polyaryl iodonium or sulfonium salt of a complex halogenide as catalyst, when irradiated with ultraviolet light and then heated, or when heated and irradiated with ultraviolet light, under a circuit mask, provides a latent image which is developable by water alone.

Abstract: Improved polyetherimide compositions and processes for their production are described. Various polyetherimide derivatives including water-soluble and tri-functionalisocyanate cross-linked resins are described. They permit production of water-based enamels and coatable particulates which may be employed in, for example, formulation of insulated electrical conductors.

Abstract: A rotary rock drill bit comprising a plurality of cutting elements or cutters mounted in the crown of the drill bit. Each cutting element comprises a thin planar layer of polycrystalline diamond bonded in the crown of the bit at a rake angle of between -10.degree. and -25.degree.. In another embodiment each cutting element comprises an elongated pin mounted at one end in the drill crown and thin layer of polycrystalline diamond bonded to the free end of the pin so as to be disposed at a rake angle of between -10.degree. and -25.degree..