Method for preparing degradable polylactic acid

A polylactic acid and lactic acid technology, applied in the field of materials, can solve the problems of high vacuum degree, restricted development, difficult dehydration, etc., and achieve the effect of high mechanical tensile strength

Inactive Publication Date: 2017-02-22
桂林市福泰建材有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reaction conditions of direct polycondensation are relatively harsh, the reaction time is long, the temperature is high, the vacuum degree is high, and the viscosity increases in the later stage, resulting in difficulty in dehydration and difficulty in significantly increasing the molecular weight, which limits the development of this method.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] A method for preparing degradable polylactic acid, the preparation steps include:

[0020] 1) Using lactic acid as raw material, dehydrating and refining under vacuum conditions to obtain lactic acid oligomers;

[0021] 2) Mix the lactic acid oligomer obtained in step 1) with a catalyst, add it to a reaction vessel, and heat to react under vacuum conditions to obtain an intermediate product of polylactic acid;

[0022] 3) Add the chain extender MDI to the reaction vessel in step 2), and heat the reaction under vacuum conditions to obtain high molecular weight polylactic acid.

[0023] The vacuum in step 1) is 3.3 kPa, the dehydration time is 8 hours, and the dehydration temperature range is 120°C.

[0024] The vacuum degree in step 2) is 1.5 kPa, the reaction temperature range is 180° C., the reaction time is 8 hours, and the reaction is accompanied by mechanical stirring.

[0025] The catalyst in step 2) is a mixture of two or three of stannous chloride, stannous octoate, and p-t...

Embodiment 2

[0030] A method for preparing degradable polylactic acid, the preparation steps include:

[0031] 1) Using lactic acid as a raw material, dehydrating and refining under vacuum conditions to obtain lactic acid oligomers;

[0032] 2) Mix the lactic acid oligomer obtained in step 1) with a catalyst, add it to a reaction vessel, and heat to react under vacuum conditions to obtain an intermediate product of polylactic acid;

[0033] 3) Add the chain extender MDI to the reaction vessel in step 2), and heat the reaction under vacuum conditions to obtain high molecular weight polylactic acid.

[0034] The vacuum degree in step 1) is 1 kPakPa, the dehydration time is 2 hours, and the dehydration temperature range is 60°C.

[0035] The vacuum degree in step 2) is 1 kPakPa, the reaction temperature range is 120° C., the reaction time is 2 hours, and the reaction is accompanied by mechanical stirring.

[0036] The catalyst in step 2) is a mixture of two or three of stannous chloride, stannous octoat...

Embodiment 3

[0041] A method for preparing degradable polylactic acid, the preparation steps include:

[0042] 1) Using lactic acid as a raw material, dehydrating and refining under vacuum conditions to obtain lactic acid oligomers;

[0043] 2) Mix the lactic acid oligomer obtained in step 1) with a catalyst, add it to a reaction vessel, and heat to react under vacuum conditions to obtain an intermediate product of polylactic acid;

[0044] 3) Add the chain extender MDI to the reaction vessel in step 2), and heat the reaction under vacuum conditions to obtain high molecular weight polylactic acid.

[0045] The vacuum in step 1) is 2.5 kPa, the dehydration time is 4 hours, and the dehydration temperature range is 80°C.

[0046] The vacuum degree in step 2) is 2 kPa, the reaction temperature range is 150° C., the reaction time is 6 hours, and the reaction is accompanied by mechanical stirring.

[0047] The catalyst in step 2) is a mixture of two or three of stannous chloride, stannous octoate, and p-to...

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PUM

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Abstract

The invention relates to a method for preparing degradable polylactic acid. The method includes the steps that firstly, lactic acid serves as the raw material and is dehydrated and refined under the vacuum condition, and lactic acid oligomer is obtained; secondly, the lactic acid oligomer obtained in the first step is mixed with a catalyst, the mixture is added into a reaction container, a heating reaction is conducted under the vacuum condition, and a polylactic acid intermediate product is obtained; thirdly, a chain extender MDI is added to the reaction container in the second step, a heating reaction is conducted under the vacuum condition, and high-molecular-weight polylactic acid is obtained.

Description

Technical field [0001] The present invention relates to the field of materials, in particular to a method for preparing degradable polylactic acid. Background technique [0002] The use of polymer materials has penetrated into various fields of industry, agriculture and daily life. Synthetic polymer materials are mainly derived from petrochemical products, which are not perishable or degradable. Except for a small amount of recycling, waste polymer materials are mostly burned and landfilled, causing serious pollution and damage to the ecological environment. Biodegradable polymer materials have good biodegradability, rich sources of raw materials, and mechanical properties similar to traditional petroleum-based polymer materials. As a chemically synthesized biodegradable polymer material, polylactic acid has abundant sources, clean production process, non-toxic and harmless, and excellent performance. It has been widely used in agriculture, textiles, packaging, biomedicine and o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/08C08G63/78C08G63/85C08G63/87
CPCC08G63/08C08G63/78C08G63/823
Inventor 李小福
Owner 桂林市福泰建材有限责任公司
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