PTC (Positive Temperature Coefficient) high polymer heating material for self-limiting temperature electric tracing band

Abstract

The invention discloses a PTC (Positive Temperature Coefficient) high polymer heating material for a self-limiting temperature electric tracing band, which is prepared from the following raw materials in percentage by weight: 5 to 9 percent of metallocene polyethylene, 65 to 70 percent of high-density polyethylene, 6 to 10 percent of vinyl copolymer thermoplastic elastomer, 1.5 to 2.5 percent of carbon fibers, 15 to 25 percent of carbon black, 0.25 to 0.35 percent of benzotriazole light stabilizer, 0.10 to 0.20 percent of hindered phenol antioxygen, 0.10 to 0.20 percent of decabromodiphenylethane, 0.10 to 0.20 percent of diisooctyl ortho-phthalate, 0.10 to 0.20 percent of dicumyl peroxide and 0.05 to 0.15 percent of nucleating transparent agent zc-3. According to the invention, the elasticity modulus of the PTC material is improved, the maximum stress and the stress of a breaking point of the PTC material are increased, so that the PTC strength and the stretch resistance performance of the PTC heating material are improved.

Description

technical field [0001] The invention relates to the field of heat tracing cables, in particular to a PTC polymer heating material used for self-limiting temperature electric tracing cables. Background technique [0002] Electric heating cable is a new high-tech product. Since it entered the application field in the 1970s, self-limiting electric heating cable has become the most common type of electric heating cable in the world today. They can be widely used in the transportation of liquid objects in pipelines, antifreeze and heat preservation of tanks, maintenance of process temperature, heating of roads, ramps, crosswalks, eaves and floors, etc. Inside the self-regulating electric heating cable, PTC polymer material for heating is distributed between two conductive cores, and its exterior is composed of polymer inner sheath, metal shielding net and polymer outer sheath. When the power is turned on, the internal PTC polymer material is heated and expanded, the resistance b...

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Problems solved by technology

[0003] At present, the PTC polymer heating material products used for self-limiting temperature electric heating cables in China have the internal core PTC heating material due to the formula adopted in the 1990s, and the limitation of processing conditions and environmental conditions in production. The tensile strength of the product is not high, and the crystallization behavior of the product is unstable, the crystallization is not perfect, and the residual thermal stress inside the PTC heating material will make the resistance of the PTC heating material unstable, the temperature rise and fall uneven, and the PTC characteristics are not good. Stability, decreased repeatability of PTC characteristics, shortened service life of materials

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