90DEG C cracking-resistant moisture-proof and flame-retardant polyethylene cable material and preparation method thereof

Abstract

The invention discloses a 90DEG C cracking-resistant moisture-resistant and flame-retardant polyethylene cable material and a preparation scheme thereof. The cable material is composed of the following components by weight: 60-90 parts of polyethylene, 10-20 parts of a vinyl copolymer, 10-20 parts of a compatilizer, 50-100 parts of a hydroxide flame retardant, 5-20 parts of sepiolite, 5-20 parts of a synergistic flame retardant, 1-3 parts of aminosilane, 1-3 parts of an antioxidant, 0.5-1.5 parts of an ultraviolet light absorber and 2-5 parts of a lubricant. The 90-DEG C cracking-resistant moisture-resistant and flame-retardant polyethylene cable material disclosed by the invention has the characteristics of resistance to a low temperature of -50DEG C, outstanding cracking resistance, insulativity and moisture resistance (volume resistivity of 70DEG C*168h after immersion), good flame retardance, low smoke, no toxicity and the like, also has the advantages of fast extrusion processingspeed, difficult generation of air holes, etc., and can be widely applied to an outer sheath layer of a 1kV-220kV cable.

Description

technical field [0001] The invention relates to the field of low-smoke, halogen-free, flame-retardant cable materials, in particular to a 90°C crack-resistant, moisture-resistant, flame-retardant polyethylene cable material and a preparation method thereof. [0002] technical background [0003] The international community and my country have increasingly stringent requirements for environmental protection and safety, and the environmentally friendly halogen-free flame-retardant polyethylene has received extensive attention. Because the halogen-free flame retardant system mainly uses hydrated hydroxide as the main flame retardant, this kind of flame retardant has low flame retardant efficiency, and the addition of inorganic flame retardant must be increased to pass the cable combustion test. Because of the increase in the filling amount of the inorganic flame retardant, the strength and toughness of the material are reduced; and because the expansion coefficient of the polyme...

AI Technical Summary

Problems solved by technology

Because the halogen-free flame retardant system mainly uses hydrated hydroxide as the main flame retardant, this kind of flame retardant has low flame retardant efficiency, and the addition of inorganic flame retardant must be increased to pass the cable combustion test

Because of the increase in the filling amount of the inorganic flame retardant, the strength and toughness of the material are reduced; and because the expansion coefficient of the polymer matrix material and the inorganic flame retardant is quite different, in the process of thermal expansion and contraction, due to uneven Shrinkage causes structural defects and internal stress, so the halogen-free flame-retardant polyethylene material is easy to crack, which is a fatal defect of cable products

[0004] The hydrated hydroxide as the main flame retardant also has the defect of easy moisture absorption. After the material absorbs moisture, its insulation performance will be greatly reduced, and there will be a greater safety hazard in cable products.

In 2018, the Shanghai Electric Power Company tested the high-voltage cables that had been laid and put into use and found that after one year of normal use of the high-voltage cables, the insulation resistance of the outer sheath of the flame-retardant cable dropped significantly, which no longer meets the requirements for the use of cables.

[0006] To sum up, it is difficult for conventional flame-retardant polyethylene cable materials to take into account environmental protection, high flame retardancy, crack resistance and moisture resistance at the same time, which has certain difficulties in the existing technology

Images