Catalyst for producing polybutylene succinate or copolyester thereof, and preparing mehtods of the catalyst

Abstract

The present invention provides a catalyst used in the production of PBS or its copolyesters and the preparation method thereof. The method comprises the following steps: (1) adding titanium alkoxide, silicon alkoxide, dihydric alcohol and metal co-catalyst into the solvent and conducting the reaction at a temperature of about 80° C. to 180° C., then removing the unreacted materials and small molecular products in the reaction system; (2) adding complexing agent into the reaction system, then collecting catalyst from the products obtained in this step. Moreover, the method may comprises steps of: (1) adding titanium alkoxide, dihydric alcohol and metal co-catalyst into the solvent and conducting the reaction at a temperature of about 80° C. to 180° C., then removing the unreacted materials and small molecular products in the reaction system; (2) adding silicon alkoxide and complexing agent into the reaction system, then collecting catalyst from the products obtained in this step. The catalyst in the present invention has higher activity and thus the catalyst additional amount is reduced which will improve the quality of the products. Moreover, the catalyst in the present invention could be used alone in the production of PBS or its copolyester without the need for other materials and it won't react with water and thus could be stored for a long time. In sum, the catalyst in the present invention has a broad prospect in industrial application.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a catalyst used in the production of PBS or its copolyesters and the preparation method thereof.BACKGROUND OF THE INVENTION[0002]Aliphatic polyesters has aroused wide attention and research from domestic and foreign scholars because of their great biodegradable and environmentally non-persistent properties. Aliphatic polyesters and in particular poly (butylene succinate) (PBS) even have additional advantage features, such as good mechanical and processing properties. Therefore, PBS, which has enormous application prospect, becomes the focus of attention in industry recently.[0003]Previous attempts at the production of PBS or its copolyesters are generally fall into two kinds of production processes, chain extending process and direct polycondensation process. In the chain extending process, chain extender is added into the reaction system to react with the organic groups of the polyesters in order to increase molecular wei...

AI Technical Summary

Benefits of technology

[0028]Compared with the traditional titanium alkoxides catalyst, the catalyst containing metal co-catalyst in the present invention, which is prepared using complexation technology, has the following advantages. Firstly, the catalyst in the present invention has higher activity and thus the catalyst additional amount is reduced which will improve the quality of the products. Secondly, the catalyst in the present invention could be used alone in the production of PBS or its copolyester without the need for other materials. Therefore, there is no need for additional preparation step as in the traditional preparation method. Thirdly, the catalyst in the present invention will not react with water and it thus could be added into the reaction system before the esterification reaction, or after the esterification reaction and before the start of the prepolycondensation. In addition, the catalyst in the present invention could be stored for a long time. In sum, the catalyst in the present invention has a broad prospect in industrial application.

Problems solved by technology

In general, the chain extenders mainly used are isocyanide alkoxides which are poisonous compounds and can't be used in food-related field.

Because of the above property, the application of PBS or its copolyesters has been limited.

In practical manufacture process, titanate-based catalyst alone can't satisfy production requirements.

In light of the above, the catalyst system in prior art has following disadvantages such as: (1) The traditional catalyst has low activity and thus the additional amount of catalyst is very high which affects the quality of the products.

Such high catalyst amount could result in many side reactions and it may also increase the melt flow rate of the products, decrease its mechanical properties and turn the products a dark yellow color.

(2) The catalyst in prior art is not convenient for practical manufacture use because titanium alkoxides would easily cause precipitation while contacting with water.

On the other hand, the catalyst in prior art is composed of several other ingredients, the technicians must prepare for each components according to its proportion which is a complex procedure comparing with the single-component catalyst.