Preparation method of PBS (poly butylenes succinate)

Abstract

The invention relates to a preparation method of PBS (poly butylenes succinate). The preparation method comprises the following steps: adopting succinic acid and butanediol with the molar ratio of (1.2-2.2): 1 as the raw materials; carrying out negative pressure esterification reaction for about 3.5 hours at the pressure of 40-80 kPaA and the temperature of 135-160 DEG C; afterwards, carrying out polycondensation reaction for about 2.5 hours at the pressure of 2-4 kPaA and the temperature of 170-210 DEG C to prepare the PBS with high molecular weight, wherein the whole reaction is carried out under the condition of catalyst existence; the catalyst is a titanium-phosphorus coordination composite catalyst generated through carrying out coordination reaction on raw materials, namely, organic phosphorus compounds and organic titanium compounds; the molar ratio of the catalyst dosage to the succinic acid dosage is 0.03%-3%. According to the PBS with high molecular weight prepared through the preparation method, the number-average molecular weight is 100 thousand or above, the tensile strength is 36 MPa or above, and the elongation at rupture is 250% or above.

Description

technical field [0001] The invention relates to a preparation method of polybutylene succinate. Background technique [0002] Polybutylene succinate (PBS) is a fully biodegradable polymer material with excellent heat resistance, mechanical and mechanical processing properties. It has a wide range of uses and can be used for surgical sutures, wound dressings, built-in materials , medicine bottles, disposable medical supplies and other medical and biomedical polymer materials, agricultural films, pesticide and fertilizer slow-release materials, agricultural materials, packaging, tableware, cosmetic bottles and other fields. [0003] At present, the synthesis of polybutylene succinate mainly includes chain extension method and direct esterification polycondensation method. The advantage of the chain extension method is that it is easy to prepare high molecular weight PBS, thereby improving the material properties, but the polymerization process of the chain extension method is ...

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Problems solved by technology

[0003] At present, the synthesis of polybutylene succinate mainly includes chain extension method and direct esterification polycondensation method. The advantage of the chain extension method is that it is easy to prepare high molecular weight PBS, thereby improving the material properties, but the polymerization process of the chain extension method is complicated. Polymerization and post-chain extension are two-step reactions, and the chain extender is generally toxic and expensive diisocyanate, which not only increases the production cost, but also is harmful to the operator during the production process, and also releases toxic substances during the biodegradation process of the material. Thus limiting its application in medical, food packaging and other fields

The process of the direct esterification and polycondensation method is simple, and no chain extender is used to avoid toxicity and resulting cost problems in the production process. However, due to the poor selectivity of catalysts in the prior art (such as tetrabutyl titanate), the by-product tetrahydrofuran The amount of THF generated is relatively large, and the existence of low-molecular by-products produced during the reaction process has a greater impact on molecular weight. The number-average molecular weight of industrialized PBS is difficult to exceed 100,000, and it is easy to cause side reactions such as decarboxylation, cyclization, and thermal degradation. , affecting the important indicators such as the hue and intrinsic viscosity of the product, which seriously restricts the application of polybutylene succinate

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