Melt polymerization method and device for semi-aromatic polyamide

Abstract

The invention relates to the technical field of polyamide polymerization, in particular to a melt polymerization method and device for semi-aromatic polyamide. The melt polymerization method of the semi-aromatic polyamide comprises the following steps that a semi-aromatic polyamide solid material firstly enters a melt polymerization section in a reactor, and melt reaction of semi-aromatic polyamide melt drops is completed in the descending process under heating of internal circulating gas and / or heating of an external heating jacket; then the melt subjected to the melt reaction enters a melt cooling section, and is cooled and solidified into solid particles from a molten state under the internal circulating gas cooling action and / or the action of an external cooling jacket; and the cooledsemi-aromatic polyamide solid particles are discharged from the bottom of the reactor. According to the melt polymerization method of the semi-aromatic polyamide, direct contact between resin and a reaction container is avoided, so that pollution to the reaction container is avoided, the cleaning and using cost of equipment is reduced, and meanwhile, the performance of the semi-aromatic polyamideis improved by increasing the polycondensation reaction rate. The invention further provides a device for melt polymerization of semi-aromatic polyamide.

Description

technical field [0001] The invention relates to the technical field of polyamide polymerization, in particular to a method and device for melt polymerization of semi-aromatic polyamide. Background technique [0002] Polyamide refers to a class of polymers whose main chain contains amide bonds (-CONH-). Due to the existence of amide bonds, there are hydrogen bonds between polyamide molecular chains. The existence of hydrogen bonds promotes the crystallization of polyamides and enhances the Interactions between molecular chains. So that the polyamide resin has good mechanical properties, wear resistance, chemical resistance, etc., so polyamide resin is often used in various fields in the form of pipes, profiles, parts, films or fibers, such as automobiles, electronic appliances, Building materials, lighting, aerospace fields, etc. [0003] In order to further increase the use temperature of polyamide resins, aromatic ring structures are often introduced into the polyamide ma...

AI Technical Summary

Problems solved by technology

However, when using a melt polymerization kettle or extruder for melt polymerization, due to the accumulation of materials, it is not conducive to the discharge of small molecule by-products, resulting in the restriction of the equilibrium reaction of polyamide molecular chain polymerization, so it can only be promoted by prolonging the polymerization time. Fully polymerized

However, due to the high melting temperature of semi-aromatic polyamides, the long residence time of semi-aromatic polyamides at high temperatures will lead to the degradation and crosslinking of nylon resins, the generation of gel particles and even the loss of melt processability directly, resulting in semi-aromatic polyamides. Performance deterioration of amide resins

In addition, when the polymerization kettle is used for the melt polymerization of semi-aromatic polyamide, it is difficult to ensure that the material is completely discharged due to the difficulty of discharging high-viscosity polyamide materials. In the process, the carbonization and degradation of the polyamide material remaining on the inner wall of the polymerization kettle and the stirring paddle will be caused, which will bring difficulties to the cleaning of the reaction equipment

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