摘要:
Disclosed is an electrically shielded enclosure having electrical components therein and a removable electrically shielded cover over an opening in the enclosure with a magnetic securement mechanism provided to removably secure the cover to the enclosure in a manner which will provide easy access, yet also provide an electrical seal between the cover and the enclosure capable of preventing the passage of electrical radiation through the joint between the cover and the enclosure. Magnets are provided on the enclosure peripherally around the opening and facing the cover, and a ferromagnetic surface is provided on the mating surface of the cover facing the magnets, with a continuous electrical seal provided between the magnets and the ferromagnetic surface on the cover to prevent the leakage of electromagnetic radiation therethrough. In one embodiment the electrical seal includes a flexible metal casing or surface, which is attached to the enclosure and positioned between the magnets and the ferromagnetic surface on the cover, and which is sufficiently flexible to be capable of conforming to the ferromagnetic surface to provide an electrical seal between the cover and the enclosure. In another embodiment, the electrical seal includes a metal mesh associated with the enclosure and positioned between the magnets on the enclosure and the ferromagnetic surface on the cover. The metal mesh is also capable of conforming to the surface of the ferromagnetic surface to thereby provide an electrical seal between the cover and the enclosure.
摘要:
This invention relates to a vulcanizable layered composition comprising at least two layers and at least one tie layer, wherein the first layer of the two layers comprises an fluid permeation prevention layer, the second layer of the two layers comprises at least one high diene rubber, and the tie layer comprises a mixture of: (1) about 50 to about 95 weight % of at least one halogenated isobutylenecontaining elastomer; (2) about 5 to about 50 weight % of at least one high diene elastomer; (3) about 20 to about 50 weight % of at least one filler; (4) about 0 to about 30 weight % of at least one processing oil; and (5) at least about 0.2 to about 15 parts per hundred of rubber (phr) of a curing system for the elastomers; wherein said fluid permeation prevention layer comprises a polymer composition having an air permeation coefficient of 25×10−12 cc·cm/cm2 sec cmHg (at 30° C.) or less and a Young's modulus of 1 to 500 MPa, said polymer composition comprising: (A) at least 10% by weight, based on the total weight of the polymer composition, of at least one thermoplastic engineering resin component having an air permeation coefficient of 25×10−12 cc·cm/cm2 sec cmHg (at 30° C.) or less and a Young's modulus of more than 500 MPa, where the thermoplastic engineering resin component is selected from the group consisting of polyamide resins, polyester resins, polynitrile resins, polymethacrylate resins, polyvinyl resins, cellulose resins, fluororesins, and imide resins, and (B) at least 10% by weight, based on the total weight of the polymer composition, of at least one elastomer component having an air permeation coefficient of more than 25×10−12 cc·cm/cm2 sec cmHg (at 30° C.) and a Young's modulus of not more than 500 MPa, where the elastomer component is selected from the group consisting of diene rubbers and the hydrogenates thereof, halogen-containing rubbers, silicone rubbers, sulfur-containing rubbers, fluoro-rubbers, hydrin rubbers, acryl rubbers, ionomers and thermoplastic elastomers, and where the total amount of the component (A) and the component (B) is not less than 30% by weight based on the total weight of the polymer composition, wherein the elastomer component (B) is dispersed in a vulcanized or partially vulcanized state, as a discontinuous phase, in a matrix of the thermoplastic resin component (A) in the polymer composition.
摘要:
The present invention is a composition including an isobutylene-based copolymer and polybutene. The copolymers may be mixed with an exfoliating compound and clay, the entire composition forming a nanocomposite. The clay may or may not have an additional exfoliating treatment present prior to mixing with the interpolymer. The composition of the invention has improved air barrier properties and processing properties, and is suitable as an air barrier. One embodiment of the invention is an elastomeric composition including at least one random copolymer of at least a C4 to C7 isomonoolefin derived unit, at least one filler, and polybutene oil having a number average molecular weight greater than 400. The copolymer may be selected from a halogenated poly(isobutylene-co-p-methylstyrene), a halogenated star-branched butyl rubber, or a halogenated butyl rubber, and mixtures thereof.