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Technique of preparing poly lactic acid in use for spinning

A preparation process, polylactic acid technology, applied in the direction of single-component polyester rayon, etc., can solve the problems of high atmosphere environment requirements, low crystallization rate, high thermal shrinkage rate, etc., to reduce production equipment, increase yield, reduce The effect of production energy consumption

Inactive Publication Date: 2007-05-09
XI'AN POLYTECHNIC UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The research on the process of preparing polylactic acid by the direct method started relatively late. The molecular weight of the prepared polylactic acid is not high, the requirements for the atmosphere environment are high, the crystallization rate is low, and the heat shrinkage rate is high, which cannot meet the requirements of spinning nonwovens.

Method used

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  • Technique of preparing poly lactic acid in use for spinning

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] 1. Lactic acid concentration

[0052] Put 300mL of lactic acid into a 1000mL round-bottomed flask, and fix it on a rotary evaporator so that the round-bottomed flask is submerged in a water bath. °C, the vacuum degree is reduced by 10,000Pa, and the evaporation temperature reaches 90°C after 1 hour. When the vacuum degree is reduced by 9,000Pa, the constant temperature concentration is completed after half an hour, and dehydrated concentrated lactic acid is obtained. The yield of concentrated lactic acid reaches 85-91%.

[0053] 2. Precondensation

[0054] Put 220g of concentrated lactic acid into the rotary bottle of rotary film evaporator, add composite catalyst 0.015% HCl, 0.1% tin powder, 0.2% self-made nano-tin powder, and heat up to 180°C at a rate of 1°C per minute in the oil bath , start the vacuum pump, slowly adjust the vacuum degree to 750Pa, polymerize under this condition for 8 hours, cool down to 110°C, and keep the vacuum degree at 80Pa for 2.5 hours to ...

Embodiment 2

[0064] Its concrete preparation method is the same as embodiment 1, and difference is:

[0065] 1. Lactic acid concentration

[0066] Put 300mL of lactic acid into a 1000mL round-bottomed flask, fix it on a rotary evaporator so that the round-bottomed flask is submerged in a water bath, control the temperature at 45°C and the pressure at 70,000Pa, and then increase the temperature by 12°C every half hour. ℃, the vacuum degree is reduced by 15,000Pa, and after 2 hours, the evaporation temperature reaches 85°C, and the vacuum degree is reduced by 10,000Pa, and the concentration is completed after constant temperature for half an hour to obtain dehydrated concentrated lactic acid. The yield of concentrated lactic acid reaches 83-90%.

[0067] 2. Precondensation

[0068] Put 220g of concentrated lactic acid into a rotary bottle, add composite catalyst 0.015% HCl, 0.2% tin powder, 0.1% self-made nano-tin powder, heat up to 170°C at a rate of 2°C per minute in the oil bath, start ...

Embodiment 3

[0075] Its concrete preparation method is the same as embodiment 1, and difference is:

[0076] 1. Lactic acid concentration

[0077] Put 300mL of lactic acid into a 1000mL round-bottomed flask, fix it on a rotary evaporator so that the round-bottomed flask is submerged in a water bath, control the temperature at 55°C and the pressure at 80,000Pa, and increase the temperature by 6 every half hour thereafter. ℃, the vacuum degree is reduced by 14,000Pa. After 2.5 hours, the evaporation temperature reaches 95℃ and the vacuum degree decreases to 12,000Pa. After half an hour of constant temperature, the concentration is completed, and the dehydrated concentrated lactic acid is obtained. The yield of concentrated lactic acid reaches 83-92%.

[0078] 2. Precondensation

[0079] Put 220g of concentrated lactic acid into a rotary bottle, add composite catalyst 0.015% HCl, 0.1% tin powder, 0.2% self-made nano-tin powder, heat up to 190°C at a rate of 3°C per minute in the oil bath, st...

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Abstract

This invention relates to a method for preparing polylactic acid used in spinning. The method comprises: (1) dehydrating and concentrating lactic acid at certain temperature and vacuum degree to obtain dehydrated and concentrated lactic acid; (2) adding composite catalyst, and pre-polycondensing at certain temperature and vacuum degree for a certain time to obtain prepolymer powder; (3) adding stabilizer and antioxidant, and polymerizing at certain temperature and vacuum degree to obtain polylactic acid particles; (4) adding heat-modified and inorganic acid, and reacting at a certain temperature for a certain time to obtain polylactic acid. The method performs bulk polymerization on lactic acid monomer, and does not need solvent or inert atmosphere, thus the process is simple and easy to control. Besides, the method also has such advantages as high yield and little pollution. The obtained polylactic acid has high molecular weight and low heat shrinkage.

Description

technical field [0001] The invention belongs to the technical field of polymer materials, and in particular relates to a preparation process of polylactic acid used for spinning. Background technique [0002] Polylactic acid (English abbreviation: PLA) is a new type of fully biodegradable material, which can be used for spinning, injection molding, manufacturing packaging materials, medical materials and other purposes. In recent years, the demand for non-woven fabrics has increased greatly, making polylactic acid materials more widely used in textiles, clothing, industry, and agriculture and forestry. The synthesis methods of polylactic acid include two-step ring-opening polymerization method and direct polycondensation method, wherein the direct polycondensation method is divided into solution polycondensation method and melt-solid phase polycondensation method. [0003] Polylactic acid products with higher molecular weight can be obtained by ring-opening polymerization. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/08C08G63/80D01F6/62
Inventor 王绍斌孙显强濮颖军杨敏鸽郁翠华陈立成
Owner XI'AN POLYTECHNIC UNIVERSITY
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