Preparation method of special low-smoke halogen-free flame retardant cladding layer material for butterfly-shaped introduction cable of access network

Abstract

The invention provides a preparation method of a special low-smoke halogen-free flame retardant cladding layer material for a butterfly-shaped introduction cable of an access network. The preparation method comprises the following steps of: (1) proportioning the components of the cladding layer material in parts by weight: 5-15 parts of high-fused ethylene-vinyl acetate copolymer, 5-15 parts of low-fused ethylene-vinyl acetate copolymer, 5-15 parts of polyethylene, 55-65 parts of a fire retardant, 10-20 parts of compatilizer, 2-3 parts of ultra-high molecular weight silicone, and 0.3-0.8 part of anti-oxygen; adding the components in a milling machine for mixing for 8-12 minutes, and discharging when the mixing temperature reaches 135-150 DEG C; (2) feeding the mixture into a double-screw-rod extruding machine, plastifying through double screw rods, and pelleting through a single screw rod, wherein for all the sections of the screw rods, a feeding section has a temperature of 90-110 DEG C, a transportation section has a temperature of 120-130 DEG C, a plastifying section has a temperature of 130-140 DEG C, and a machine head has a temperature of 135-145 DEG C; and pelleting is carried out by using an air cooling and hot cutting process; and finally drying the made particles to obtain a finished product. The cladding layer material manufactured by the invention is used as a special material of a rubber-insulated optical cable, and has the advantages of good material flowing property, good binding property and good product quality. Furthermore, the optical attenuation degree can be greatly reduced.

Description

technical field [0001] The invention relates to a preparation method of a special low-smoke, halogen-free and flame-retardant cladding layer material for a butterfly-shaped lead-in optical cable for an access network. Background technique [0002] The butterfly-shaped lead-in optical cable for the access network, commonly known as the leather cable, is the most complicated link in the fiber-optic access project, and the indoor wiring close to the user is the most complicated link. wiring needs. The covered cable has a single-core, double-core structure, and can also be made into a four-core structure, that is, the cross-section is 8-shaped, and the strengthening member is located in the center of the two circles. Metal or non-metal structure can be used, and the optical fiber is located at the geometric center of the 8-shaped . The coating layer of the leather cable is mainly low-smoke, halogen-free and flame-resistant fuel. The leather cable is a newly developed product i...

AI Technical Summary

Problems solved by technology

The material components to prepare the existing common low-smoke and halogen-free materials are as follows: use low-melt index ethylene-vinyl acetate copolymer (melt index between 2-8) as the base material, with a little compatibilizer, and small molecular weight The low-smoke and halogen-free coating material produced in this way has many disadvantages: first, the sheath cable is a thin line, and if it is mass-produced, the extrusion speed is quite high, and the material is required to be The surface is still very good in the case of rapid extrusion, but the existing low-smoke and halogen-free materials use low-melt ethylene-vinyl acetate copolymer as the base material, and the fluidity of the material is not good. It is difficult to raise it very high, and the casting phenomenon is serious; secondly, when the cross-section of the leather cable is in the shape of 8, due to mold restrictions and other reasons, the requirements for the discharge of the middle joint are very high. Due to the poor fluidity of the halogen material, the material is easy to break at the joint, and the bonding strength is too low, the surface is rough, etc.; again, the cladding material is in direct contact with the optical fiber and its reinforcement. It has a great impact on the attenuation of optical fiber signals. Only a small amount of compatibilizer is used in the existing ordinary low-smoke halogen-free flame-retardant cladding materials, which makes the signal attenuation of fiber optic cables generally large.