Catalyst for preparing polybutylene succinate and copolyesters thereof and preparation method thereof

Abstract

The invention provides a catalyst for preparing polybutylene succinate and copolyesters thereof and a preparation method thereof. The preparation method comprises the following steps: (1) adding titanium alkoxides, silica-alkoxides, dibastic alcohol and a metal cocatalyst into solution for reaction at a temperature of between 80 and 180DEG C, and separating and removing unreacted substances and micromolecular products in a reaction system; and (2) adding a complexing agent for continuous reaction and collecting the catalyst in reaction products. Or the preparation method comprises the following steps: (1) adding titanium alkoxides, dibastic alcohol and a metal cocatalyst into solution for reaction at a temperature of between 80 and 180DEG C, and separating and removing unreacted substancesand micromolecular products in a reaction system; and (2) adding silica-alkoxides and a complexing agent for continuous reaction and collecting the catalyst in reaction products. The catalyst has high catalytic activity, low addition volume, good product quality, no reaction when meeting water at normal temperature, easy long-term storage and good industrial application prospect and value.

Description

technical field [0001] The invention relates to catalysts for the preparation of polybutylene succinate and its copolyesters. Background technique [0002] Aliphatic polyester has attracted extensive attention and research because of its good biodegradability and no pollution to the environment. Among them, polybutylene succinate (PBS) and its copolyester have become the easiest kind of aliphatic polyester to realize practical application due to their good mechanical properties and processing properties, and are currently the focus of attention in the industry. . [0003] The production of polybutylene succinate and its copolyester generally adopts two methods: chain extension method and direct polycondensation method. The chain extension method is to use the chain extender to react with the organic groups of the polyester to increase the molecular weight of the polyester. The main chain extender used at present is the substance of diisocyanocyanate alkoxide, because this...

AI Technical Summary

Problems solved by technology

In actual production, a single titanate catalyst often cannot fully meet the requirements, and needs to be compounded with other compounds to form a composite catalyst

[0005] There are certain technical defects in the above-mentioned catalyst systems, which are mainly manifested in: (1) The activity of the catalyst is low, and the addition amount is high, which affects the quality of the final product

Titanium alkoxide catalysts are usually used, and the addition concentration of its active ingredient (titanium element) exceeds 500ppm in terms of polybutylene succinate (that is, 500×10 -6 gTi / gPBS, the same below), sometimes even more than 700ppm, such a high addition will cause more side reactions and increase the melt mass flow rate of the product, decrease the mechanical properties, and seriously yellow the color

(2) The catalyst is inconvenient to use, which brings difficulties to the production operation

Titanium alkoxides will precipitate when they meet water at room temperature, and in the synthesis process of PBS, the product of the esterification stage is water, so titanium alkoxides as catalysts can only be added after esterification and not after esterification. On the other hand, multiple substances are used as catalysts at the same time, which also causes certain difficulties in addition. Operators need to prepare catalysts in advance, and the process is far less convenient than using a single catalyst