Nylon 56 short fiber and melt direct spinning preparation method thereof

The invention discloses a melt direct spinning preparation method of nylon 56 short fibers. The method includes steps: (1) allowing reaction of bio-based pentamethylene diamine and adipic acid in water under nitrogen protection to obtain a nylon 56 salt solution; (2) adding the nylon 56 salt solution and a molecular weight regulator into a reactor, and keeping the pressure under the condition that the temperature is 210-240 DEG C and the pressure is 1.7-1.85MPa; releasing the internal pressure of the reactor, and heating to 280-290 DEG C; vacuumizing and stirring to obtain nylon 56 polymer melt; (3) feeding the nylon 56 polymer melt into a spinning manifold; subjecting the nylon 56 polymer melt to spinning through a spinneret, cooling, leading to a winding machine to realize finishing and conditioning, and sequentially performing drafting, crimping, finishing, relaxed heat setting and cutting to obtain the nylon 56 short fibers. The melt direct spinning preparation method has advantages of short process, high efficiency and product stability and provides guidance for industrial direct spinning of bio-based nylon and nylon polymers.