Cross-insulated insulated wire and cable has excellent electrical performance, good operating safety performance and thermal overload mechanical properties, as well as installation and maintenance of simple and so on.
The cross-link mechanism of the wire and power cable manufacturers insulation material is a physical or chemical method , so that the polymer insulation material from the linear molecular structure of a three-dimensional network structure , from the thermoplastic material into a thermometer insulation material , thereby improving the aging resistance of insulating materials , Mechanical and environmental resistance . The United States from the fifties invented cross-linked insulated wire and 2/0 welding cable , the sixties gradually applied . Over the past decade , more and more widely used in domestic cross-linked insulation , which replaced the oil paper insulation , and is gradually replacing PVC plastic insulation .
There are many varieties of cross-linked insulation , from the mechanism of cross-linking is mainly divided into two categories , namely , physical cross-linking and chemical cross-linking . 1 , chemical cross-linking : chemical cross-linking and high temperature cross-linking and low temperature cross-linking two methods . (1 ) high temperature cross-link , also known as peroxide cross-linking , the general use of organic peroxides as a cross-linking agent , under the action of heat , decomposition of active free radicals , the free radicals on the polymer carbon chain to produce active point , And produce CC cross-linked bonds , the formation of three-dimensional network structure .
High temperature cross-linking , including steam cross-link and dry cross-linking two forms into technology , foreign cross-linked twin and earth cables in the sixties most of the steam cross-linking process , due to steam cross-link to increase the moisture content of insulation , insulation quality is not good Has been completely eliminated ; the seventies began , commonly used abroad dry cross-linking process , the use of high-pressure curing pipe , rapid heating method for cross-linking . (2 ) low temperature cross-link , also known as warm water cross-linked or silane cross-linked , cable in 70-90 ℃ in the warm water cross-linking , insulation in the cross-linking agent - silane in the water , the linear structure of the formation of reticular cross-linking structure .
Physical cross-linking : also known as irradiation cross-linking , divided into γ-ray cross-linked and electron beam cross-linking two methods . (1 ) γ-ray cross-linking due to the low dose rate , the process of irradiation can not penetrate the cable core , so now only in the heat shrinkage of the application of cross-linking , and wire and car cables for battery production generally do not use γ- Ray cross-linking .