Ultraviolet deep-crosslinked expansion flame-retardant polyolefine cable material, and preparation method of insulating or jacket layer thereof

Abstract

The invention relates to an ultraviolet deep-crosslinked expansion phosphorus-nitrogen flame-retardant polyolefine cable material, and a preparation method of an insulating or jacket layer thereof. Polyethylene or graft-modified polyethylene and / or ethylene-vinyl acetate or graft-modified copolymer thereof are used as base materials, surface-modified expansion phosphorus-nitrogen halogen-free flame retardant, cation photoinitiator, free-radical photoinitiator, polyfunctional group crosslinking agent and composite antioxidant are added, and flame-retardant synergist, synergistic smoke suppressor and processing assistant are matched to obtain the ultraviolet deep-crosslinked expansion phosphorus-nitrogen flame-retardant polyolefine cable material. The preparation method comprises the following steps: proportionally and evenly mixing the materials to obtain granules, extruding to obtain an optical crosslinked expansion flame-retardant wire cable insulating layer or jacket layer, and radiating by a specific ultraviolet source for several seconds to obtain the deep-crosslinked insulating layer or jacket layer. The new material and new technology have the advantages of low investment required for crosslinking equipment, simple technique, energy saving, environmental protection, high production efficiency, low cost and good product quality, and can be widely used for manufacturing rail transportation cables, various mechanical wires, indoor assembly wires and the like.

Description

technical field [0001] The invention belongs to the technical field of preparation of cross-linked flame-retardant polyolefin wires and cables, and in particular relates to a method for preparing flame-retardant polyolefin cable material and its insulating layer or sheath layer through ultraviolet light deep cross-linking expansion (type phosphorus-nitrogen type). Background technique [0002] Cross-linked polyolefin materials have the characteristics of excellent electrical properties, high long-term use temperature, corrosion resistance, good pressure and heat resistance, and high mechanical strength. They are increasingly used in the manufacture of insulation or sheath layers for cross-linked wires and cables. However, the main disadvantage of cross-linked polyolefin materials is that they are easy to catch fire and cause fires. At present, the most commonly used halogen-containing flame-retardant polyolefin materials will release a large amount of smoke and corrosive hyd...

AI Technical Summary

Problems solved by technology

However, in actual use, the applicant found that the above-mentioned patent application has the following two defects: one is that no matter whether it is an intumescent phosphorus-nitrogen flame retardant or a metal hydroxide inorganic filler, in addition to seriously deteriorating the polymerization In addition to the mechanical properties and processing properties of the material matrix, the more negative impact is that it seriously hinders the penetration ability of ultraviolet light in polymer materials, so that the bottom layer of thicker samples (such as 1.5mm and above thickness) cannot be fully exchanged. Second, due to the fact that intumescent phosphorus-nitrogen flame retardants are easy to absorb moisture, they often absorb moisture in the environment during use, resulting in poor electrical properties and flame retardant properties of the material. severely degraded performance

Therefore, how to overcome the shortcomings of insufficient crosslinking depth caused by adding intumescent phosphorus-nitrogen halogen-free flame retardants, improve the penetration depth of ultraviolet light in intumescent flame-retardant polymer composites and the efficiency of photoinitiated crosslinking, and how to solve The moisture absorption problem of intumescent flame retardants during use has become a key technical issue in the development of photo-crosslinkable intumescent phosphorus-nitrogen halogen-free flame-retardant cable materials

[0005] Polymer UV crosslinking mainly uses two types of photoinitiators: the most commonly used type is free radical photoinitiators, such as hydrogen abstraction type photoinitiator benzophenone (BP) and cracking type photoinitiator benzoin Dimethyl ether (BDK), etc., after absorbing ultraviolet light, they generate free radicals and initiate crosslinking reactions. However, due to the weak penetration of ultraviolet light, it is difficult to penetrate deep into the material, especially in thicker samples containing fillers. free radical crosslinking reaction