CPC C08G 69/30 (2013.01) [C08G 69/06 (2013.01); C08G 69/26 (2013.01); C08L 77/00 (2013.01)] | 16 Claims |
1. A method for synthesizing a long carbon chain semi-aromatic nylon, wherein the method comprises:
mixing a wet powdery nylon salt, an antioxidant, a catalyst, a surfactant, and pellets and carrying out a one-step solid state polymerization under dynamic mixing to obtain a powdery nylon,
wherein the wet powdery nylon salt has a solvent content of 5-40% wt, and is prepared by salt-forming reaction of terephthalic acid and a long carbon chain diamine with 10-14 carbon atoms in the solvent,
wherein the pellets promote stirring and mixing of materials and reduce sticking of materials to a wall under dynamic mixing,
wherein the one-step solid state polymerization includes pre-solid state polymerization and post-solid state polymerization; in the pre-solid state polymerization, gradually increasing temperature of the system from 150-190° C. to 180-220° C., ensuring the nylon salt and the prepolymer not to be molten, and increasing the solvent vapor pressure to 1.00-2.20 MPa during the period; in the post-solid state polymerization, gradually reducing the system pressure to vacuum and holding for at least 1 h; the temperature of the post-solid state polymerization should not be lower than the termination temperature of the pre-solid state polymerization; and
wherein, in the pre-solid state polymerization, gradually increasing the temperature from 150-190° C. to 180-220° C. includes: holding the temperature at 150-190° C. for 0.5-2 h, then increasing the temperature to 180-220° C. at a rate of 5-10° C. for 0.5-1 h, and holding for 0.5-2 h.
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