Grade-1E K2-type radiation cross-linked halogen-free flame-retardant cable material for nuclear power plant and preparation method thereof

Abstract

The invention relates to a grade-1E K2-type radiation cross-linked halogen-free flame-retardant cable material for a nuclear power plant and a preparation method thereof, belonging to the field of new chemical materials. The cable material comprises raw materials including base resin EVA (ethylene-vinyl acetate copolymer), flame retardants A and B, a flame retardant synergist, basic antioxidants 1010 and 168, a radiation-resistant auxiliary agent 4,4'-thiobis(6-tertiary-butyl-3-methylphenol) and a processing agent; and the preparation method comprises the process steps of material weighing, pretreatment, mixing, extrusion granulation, drying and the like. The cable material is a red-phosphorus-free halogen-free environment-friendly flame-retardant material, phenoxy polyphosphazene is used as a main flame retardant in a flame-retardant system of the cable material, an inorganic flame retardant is auxiliary, the flame-retardant system accounts for a small weight percentage of the material, and the cable material is high in flame-retardant efficiency and excellent in mechanical properties, processability and radiation resistance, so that the cable material is a novel environment-friendly flame-retardant material which has excellent comprehensive properties and is suitable for a nuclear power plant environment.

Description

technical field [0001] The invention relates to an irradiation cross-linkable halogen-free flame-retardant cable material and a preparation method thereof, in particular to a 1E-class K2-type irradiation cross-linkable halogen-free flame-retardant cable material for nuclear power plants and a preparation method thereof, belonging to The field of new chemical materials. Background technique [0002] The use of nuclear power to generate electricity has become an important way for countries around the world to solve energy problems. There are already 17 countries whose nuclear power generation accounts for more than 25% of the total power generation. In the United States, there are more than 100 nuclear power units in operation, the largest in the world, with an installed capacity of 97.41 million kilowatts. In 2000, nuclear power generation was 753.9 billion kWh, accounting for 19.83% of the total power generation in the United States. At present, there are 8 operating units i...

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Problems solved by technology

[0004] At present, there are mainly two ways to prepare nuclear-grade cable materials. One is to choose polymer materials with strong radiation resistance as the matrix of cable materials, such as polyimide, which contains highly stable Benzene ring structure, complex production process, large one-time equipment investment, and extremely high cost; the second is to add antioxidants that can capture a large number of free radicals in polymer materials. This method does not need to change equipment, and the production process is mature.

Nuclear-grade cables have strict requirements on the flame retardant properties of materials. The traditional halogen-free flame retardant cables mainly have the following disadvantages: First, in order to meet the requirements of flame retardant properties, magnesium hydroxide, such as magnesium hydroxide, is usually added to the matrix of cable materials. A large number of inorganic flame retardants, such as aluminum hydroxide and red phosphorus, although red phosphorus has high flame retardant efficiency, its compatibility with the base resin is poor and the color of the prepared material is single, and the flame retardant efficiency of magnesium hydroxide and aluminum hydroxide is low In order to achieve a certain flame retardant effect, it must be added in a large amount to the base resin, which will inevitably cause a serious decline in the mechanical properties and processing properties of the material, and at the same time reduce the temperature resistance level of the material

The halogen-free flame retardant material described in this patent is used in the formula for preparing the cable insulation layer for nuclear power plants, using aluminum hydroxide / high molecular weight ammonium polyphosphate / melamine cyanurate / melamine pyrophosphate Flame retardant system, the addition amount of the flame retardant system is 100 parts, the composition of the flame retardant system is complex, the amount of addition is large, and the compatibility of each component with the polymer is different, resulting in a low elongation at break of the product and a slow extrusion processing speed. Secondly, because the pH of ammonium polyphosphate is slightly acidic, it is easy to absorb moisture in the air, deliquescence occurs and the thermal stability is not good, and it is easy to be precipitated by heat and mechanical action during processing, resulting in reduced performance and service life of the product

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