Preparation method of polylactic acid with high molecular weight

A high-molecular-weight, polylactic acid technology, applied in the field of preparation of high-molecular-weight polylactic acid, can solve the problems of high vacuum degree, restricted development, difficulty in dehydration, etc., and achieve the effect of high mechanical tensile strength

Inactive Publication Date: 2017-01-04
桂林市福泰建材有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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 preparation method of high molecular weight polylactic acid, the preparation steps comprising:

[0020] 1) Using lactic acid as a raw material, dehydration and refining are carried out under vacuum conditions to obtain lactic acid oligomers;

[0021] 2) mixing the lactic acid oligomer obtained in step 1) with a catalyst, adding it to a reaction vessel, and heating and reacting under vacuum conditions to obtain a polylactic acid intermediate product;

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

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

[0024] The vacuum degree in step 2) is 1.5kPa, 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...

Embodiment 2

[0030] A preparation method of high molecular weight polylactic acid, the preparation steps comprising:

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

[0032] 2) mixing the lactic acid oligomer obtained in step 1) with a catalyst, adding it to a reaction vessel, and heating and reacting under vacuum conditions to obtain a polylactic acid intermediate product;

[0033] 3) Add chain extender HDI 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 ...

Embodiment 3

[0041] A preparation method of high molecular weight polylactic acid, the preparation steps comprising:

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

[0043] 2) mixing the lactic acid oligomer obtained in step 1) with a catalyst, adding it to a reaction vessel, and heating and reacting under vacuum conditions to obtain a polylactic acid intermediate product;

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

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

[0046] The vacuum degree in step 2) is 2kPa, 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 th...

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Abstract

The invention relates to a preparation method of polylactic acid with high molecular weight. The method comprises the preparation steps that 1, lactic acid is used as a raw material and dewatered and refined under a vacuum condition, and a lactic acid oligomer is obtained; 2, the lactic acid oligomer obtained in step 1 is mixed with a catalyst, the mixture is added into a reaction vessel, heating is carried out for a reaction under the vacuum condition, and a polylactic acid intermediate product is obtained; 3, a chain extender HDI is added into the reaction vessel in step 2, heating is carried out for a reaction under the vacuum condition, and the polylactic acid with high molecular weight is obtained.

Description

technical field [0001] The invention relates to the field of materials, in particular to a preparation method of high molecular weight 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 and difficult to degrade. For waste polymer material products, except for a small amount of recycling, the rest are mostly incinerated and landfilled, causing serious pollution and damage to the ecological environment. Biodegradable polymer materials have good biodegradability, rich sources of raw materials, and have similar mechanical properties to traditional petroleum-based polymer materials, so they are very popular. As a chemically synthesized biodegradable polymer material, polylactic acid has abundant sources, clean production process, non-toxic and harmless, and excellent performance. ...

Claims

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Application Information

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