EVA foam material is also called the polymer electrolyte. Used for isolation belt or different potential of the conductor of electricity, make the electric current can flow in a certain direction of polymer materials. The volume resistivity generally greater than 109 Ω · cm. Most polymer materials with excellent insulation, many varieties, wide raw material sources, easy processing, reliable performance, so the application is very extensive. In the 1980 s, in some developed countries consumption accounted for more than 5% ~ 15% of total consumption in polymer materials.
EVA terms material
Electronic insulation materials mainly used in the insulation protection of semiconductor components and electronic equipment. (1) printed circuit board, that is, copper-clad version. Laminate substrate for resin, known as rigid, copper-clad often use epoxy, phenolic resin board; Substrate for polymer thin film or single heat-resistant glass cloth, says flexible copper-clad version, often use polyester, polyimide, containing fluorine polymer film. (2) packaging materials, used to prevent the moisture and the influence of impurity of semiconductor components parameters. At present, about 90% or more of the semiconductor components using plastic package. Mainly with epoxy resin and silicone resin, followed by phenolic resin, polyester, polybutadiene, etc. (3) semiconductor device with insulation film, is big gauge film integrated circuits and other semiconductor components of surface protective film (including contact coating, passivation film, moistureproof and shockproof film, prevent soft error alpha covered film, etc.) and the interlayer insulating film. Such as the aromatic heterocyclic polymer is given priority to with polyimide.
Electrical insulating material is mainly used in motor, electrical appliances, such as armature slot wedge in the generator, electric motor, stator winding and rotor winding insulation. According to the shape is divided into six categories:
1) insulating varnish, resin and adhesive. Such as insulating paint, silicon steel sheet varnish, enameled wire paint, potting resin liquid, and a variety of adhesives such as commonly used epoxy resin, polyester, polyurethane, organic silicon resin, polyimide alkyd resin (see alkyd resin coating), etc.
(2) impregnated fiber products. Such as resin impregnation of various kinds of cotton, silk, synthetic fiber and glass fiber or fabric of the proceeds of the insulation cloth, belt and other products.
3. Layer pressing category. A variety of organic or inorganic substrate after impregnating resin laminated material products, such as a variety of laminate.
(4) plastic products category. By adding various resin organic or inorganic filler, such as the television cabinet, instrument, instrument shell, electric switch connector shell and so on.
(5) thin films, synthetic paper and composite products. All kinds of polymer film capacitor dielectric materials, for example, the commonly used polystyrene, polypropylene, polyester, polycarbonate, polytetrafluoroethylene, and polyimide film; All kinds of synthetic fiber insulating paper, such as aromatic polyamide fiber paper, polyester fiber paper; All kinds of insulation adhesive tape, electrical tape, etc.
6. Rubber products. Such as all kinds of wire and cable insulation and sheath, heat shrinkable tube, silicone rubber insulated terminals, etc.
The future development of the new trend of development of EVA foam material issue is to further improve the heat resistance of materials, development of F, H and higher heat resistance of new materials; Development of superconducting cryogenic insulation material; Developing excellent insulation and water resistance of resistance to radiation, freon insulation materials; High frequency dielectric materials developed high temperature resistance, good processability and development with other special performance (such as thermal conductivity, high purity, photographic, etc.) of insulation.