Ultraviolet deep crosslinked halogen-free flame-retardant ethylene propylene rubber cable material and preparation method of insulating or sheathing layer thereof

Abstract

The invention relates to an ultraviolet deep crosslinked halogen-free flame-retardant ethylene-propylene-diene monomer (EPDM) rubber cable material and a preparation method of an insulating or sheathing layer thereof. The method is characterized by comprising the following steps of: mixing and extruding to form the cable material by using EPDM rubber and graft modified EPDM rubber as base materials and compounding a metal hydroxide flame retardant, light initiating bodies of a cationic photoinitiator and a free radical photoinitiator and the like; and then performing molten on-line continuousultraviolet irradiation on a coated cable insulating or sheathing layer in ultraviolet irradiation cross-linking equipment provided with a thermal electronic excited medium-voltage mercury arc lamp or a microwave excited H-shaped, D-shaped or V-shaped electrodeless lamp serving as a specific light source to prepare the ultraviolet deep crosslinked halogen-free flame-retardant EPDM rubber cable insulating or sheathing layer. The technology has unique advantages that: the required cross-linking equipment is low in investment; the process is simple and high in production efficiency; the product has low cost and good quality; and the method is energy-saving and environment-friendly, and is widely used for manufacturing high-performance crosslinked flame-retardant rubber wire and cable products.

Description

technical field [0001] The invention belongs to the field of rubber cross-linked flame-retardant cables, in particular to a preparation method of ultraviolet-light deep cross-linked low-smoke halogen-free flame-retardant EPDM cable insulation or sheath material and the insulation or sheath layer. Background technique [0002] Ethylenepropylene diene monomer (EPDM) is widely used as wire and cable insulation or sheath material because of its excellent electrical properties, excellent heat and aging resistance, and good low temperature flexibility. However, the oxygen index of EPDM rubber is only about 20%, which is easy to catch fire and cause a fire. Therefore, flame-retardant EPDM wires and cables are required to be used in many occasions, especially in rail transit, nuclear power, mining and shipbuilding industries that require high flame-retardant wires and cables. [0003] Chinese Patent Publication No. CN1106425 discloses the use of high-energy electron beam radiation ...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to overcome the shortcoming that exists in the above-mentioned existing ultraviolet light cross-linked EPDM technology, the contriver finds cationic photoinitiator and free radical photoinitiator surprisingly in long-term electric wire and cable development research and production practice The combined novel photoinitiation system has a light intensity of 400-4000mW / cm 2 , The wavelength is 200-500nm and its emission spectrum intensity distribution matches the cationic photoinitiator’s absorption spectrum and its intensity distribution. Under the condition of a specific ultraviolet light source, the molten state is carried out on-line continuous ultraviolet irradiation crosslinking for 0.5-20 seconds to obtain deep crosslinking At the same time, grafted modified EPDM rubber, surface-modified sub-nanometer or nano-scale metal hydroxide, flame retardant synergist and smoke suppressant are used in the formulation system of halogen-free flame retardant materials. Various comprehensive technical means are used to solve key technical problems such as the poor deep penetration ability of ultraviolet light in metal hydroxide halogen-free flame retardant materials with large additions and the serious deterioration of material mechanics and processing properties, so as to provide a cross-linking Low equipment investment, simple process, high production efficiency, low product cost, good performance, energy saving and environmental protection, and can achieve UV depth of UV cross-linked low-smoke, halogen-free, flame-retardant EPDM cable new material and new technology with uniform depth Cross-linked halogen-free flame-retardant (referring to low-smoke halogen-free flame-retardant) EPDM cable material (referring to cable insulation or sheath material) and its method for preparing cable insulation layer or sheath layer,