A kind of preparation method of the mixture of glycolide and lactide

Abstract

The invention provides a preparation method of a glycolide and lactide mixture. The preparation method comprises the following steps: S1: dehydrating raw materials: adding glycolic acid and lactic acid into a first reaction container according to a preset ratio, performing stirring, performing heating for melting through a heating device, performing vacuumizing by using a vacuumizing device untilthe temperature is increased to a first preset temperature, and keeping vacuumizing until a first preset time T1 is reached; and S2, generating the glycolide and lactide mixture: adding a catalyst into the first reaction container, raising the temperature to a second preset temperature while stirring, and performing vacuumizing by the vacuumizing device until no fraction is distilled out. Lactic acid capable of generating lactide is added into a reaction material for synthesizing the glycolide, the raw materials are dehydrated and depolymerized to generate the glycolide and lactide mixture, and the generated lactide does not influence synthesis of the polyglycolide, so convenience is brought for subsequent application, and the carbonization phenomenon in the reaction process can be greatlyweakened.

Description

technical field [0001] The invention relates to an easily degradable polymer monomer, in particular to a method for preparing a mixture of glycolide and lactide. Background technique [0002] Among many biodegradable materials, polyester materials represented by polylactic acid, polyglycolic acid and their copolymers are easy to be decomposed and metabolized by various microorganisms or enzymes in animals and plants in nature, and finally form carbon dioxide and water. Recently, biodegradable materials have been widely used in the field of biomedicine, such as surgical sutures, orthopedic fixation, tissue repair materials, and drug controlled release systems. [0003] However, both polyglycolide and polylactic acid have some shortcomings. Polylactic acid homopolymer has a tight structure and poor tensile properties due to its high crystallinity. Compared with other degradable polymers, the degradation rate of polylactic acid is quite slow under natural conditions. However,...

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Problems solved by technology

However, this method is still difficult to reduce the production cost due to the slow production rate of the circular dimer

U.S. Patent No. 4,727,163A discloses a method for preparing a cyclic ester by heating a copolymer of glycolic acid and high-temperature-resistant polyether. Although the high-temperature-resistant polyether can be reused by adding glycolic acid to copolymerize multiple times, it needs to consume a large amount of multi-polymer At the same time, the polymer will have many side reactions at high temperature, such as isomerization and carbonization of the polymer, which makes it difficult to clean the reactor

[0006] U.S. Patent US5830991A discloses a kind of adding high boiling point polar organic solvent to polyglycolic acid oligomer to reduce the viscosity of reaction system and depolymerization reaction temperature, US6891048B2 discloses a kind of polyglycolic acid oligomer and polar organic solvent to add depolymerization at the same time system and at the same time cause sulfate or organic acid salt stabilizers in the form of divalent or multivalent cations to prevent side reactions, but the crude glycolide product is difficult to purify due to the mixture of such solvents

[0007] In the above method, the method of increasing the conversion rate of glycolide is achieved by adding a substance with a lower saturated vapor pressure than glycolide, and the obtained monomer crude product is difficult to purify because it is mixed with more impurities.

At the same time, the extra added material needs to absorb a lot of heat during distillation, which increases energy consumption

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