Process for preparing fatty polyester

Abstract

The method for preparing high molecular weight fatty polyester whose number-average molecular weight is 28000-40000 and weight-average molecular weight is 6000-13000 by adopting two-stage process is characterized by that it utilizes binary acid, dibasic alcohol and (or) hydroxy acid to make polycondensation reaction to prepare terminal hydroxyl polyester performed polymer, then adopts organic silicon azane compound as chain extender to make chain expansion reaction, the mole ratio of terminal hydroxyl polyester performed polymer and organic silicon azane chain extender is 1:0.8-2.0, and the Chain expansion reaction temp. is at 90-200 deg.C. It is simple in preparation process, non-toxic, high-effective, moderate in reaction condition, and suitable for industrial production.

Description

Technical field: [0001] The invention relates to a preparation method of aliphatic polyester. In particular, a two-step method is used to prepare high molecular weight polyesters with a number average molecular weight of 28,000 to 40,000 and a weight average molecular weight of 60,000 to 130,000. Background technique: [0002] The currently used polyethylene, polypropylene, polystyrene and other plastics have excellent comprehensive properties and are widely used in agricultural mulch, various soft and hard packaging, utensils, fast food boxes and many other aspects. However, because these materials are very stable in nature, their wastes are difficult to degrade in nature, and it takes one to two hundred years to completely degrade. For this reason, since the 1980s, people have conducted a lot of research to prepare new degradable materials. Aliphatic polyester is a degradable material and can be widely used in many aspects such as medical treatment, agriculture, packaging, etc....

AI Technical Summary

Problems solved by technology

In addition, Japanese patents Ping 6-256461 and Ping 6-322091 adopt a two-step method of polycondensation and chain extension to prepare high molecular weight aliphatic polyesters with a molecular weight of more than 30,000. This method mainly uses dibasic acids and dibasic alcohols for polycondensation, and then The chain extender is used for chain extension. One type of chain extender used is diisocyanate (Ping 6-256461). This type of chain extender is toxic, and there are many side reactions during the chain extension process, which can easily cause the color of the product to deepen; the other type Chain extenders are polybasic acid anhydrides. For example, the patent of Ping 6-322091 uses tetrabasic acid dianhydrides. Due to the complex structure of the chain extender itself, it is difficult to prepare, which is not conducive to the industrialization of aliphatic polyester preparation.