Self-flame-retardant PBT composite material and preparation method thereof

Abstract

The invention discloses a self-flame retardant PBT composite material and a preparation method thereof. The self-flame-retardant PBT composite material is prepared from the following raw materials in parts by mass: 40 to 50 parts of terephthalic acid, 45 to 55 parts of 1, 4-butanediol, 15 to 25 parts of pyromellitic acid, 3 to 10 parts of guanidine sulfamate, 2 to 4 parts of amino trimethylene phosphonic acid, 1 to 2 parts of a catalyst and 10 to 15 parts of functionalized layered double hydroxides. The preparation method comprises the following steps: S1, mixing terephthalic acid, 1, 4-butanediol and a catalyst, carrying out pre-esterification reaction for 2-3 hours under the conditions of 0.1 MPa and 200-220 DEG C, then adding pyromellitic acid, guanidine sulfamate and amino trimethylene phosphonic acid, heating to 245-270 DEG C, and carrying out stirring reaction for 1-1.5 hours; and S2, vacuumizi1ng the reaction system in the S1 to 50-100 Pa, carrying out condensation polymerization at 240-255 DEG C for 3-6 hours, then adding the functionalized layered double-metal hydroxide, carrying out stirring reaction at 250-270 DEG C for 1-2 hours, and cooling and curing. According to the method disclosed by the invention, a flame-retardant substance is embedded into a PBT molecular chain, so that microcosmic molecular modification is realized, the PBT material is endowed with a self-flame-retardant characteristic, the problem of phase layering is avoided, and the mechanical strength and the mechanical property of the PBT material are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of polymer synthesis, and in particular relates to a self-flame-retardant PBT composite material and a preparation method thereof. Background technique [0002] Polybutylene terephthalate, also known as polytetramethylene terephthalate, or PBT for short, is a semi-crystalline thermoplastic polyester formed by polycondensation of terephthalic acid and 1,4-butanediol. PBT is one of the toughest engineering thermoplastics with excellent chemical stability, mechanical strength, electrical insulation properties and thermal stability. However, the limiting oxygen index of PBT is low, only 20-22%. It is a flammable material. At the same time, its combustion and decomposition will release a large amount of toxic gases and harmful substances, accompanied by the melting and dripping of the combustion body, which further accelerates the combustion. . [0003] At present, flame retardants are mainly mixed into PBT mat...

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Problems solved by technology

[0003] At present, flame retardants are mainly mixed into PBT materials by physical doping, but the compatibility between flame retardant particles and PBT materials is poor, and there is a problem of crystallization of flame retardants at the PBT interface, resulting in poor dispersion stability of flame retardants, especially It is an inorganic flame retardant such as aluminum hydroxide, magnesium hydroxide, ammonium polyphosphate, zinc borate, antimony oxide and molybdenum compounds. It is completely incompatible with PBT materials, and phase delamination occurs, reducing the mechanical strength and mechanical properties of composite PBT materials. At the same time, since the physical doping method is only a mixed modification of different components on the macroscopic level, it is impossible to achieve chemical modification of the PBT molecular chain at the micro-nano level, and it is impossible to make the PBT material itself possess flame-retardant properties, anti-corrosion Burning effect is relatively limited

For example, the patent application number CN201510422376.6 discloses a glass fiber reinforced flame-retardant PBT material and its preparation method; such as the patent application number CN201710266625.6 discloses a high glow wire reinforced flame-retardant PBT composite material and its The preparation method, the above-mentioned patents all adopt the physical doping method to mix the flame retardant into the PBT base material, resulting in a significant decrease in the structural stability of the PBT composite material, and the flame retardant effect needs to be improved

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