Purification method of polyvinyl alcohol

A technology of polyvinyl alcohol and purification method, applied in the field of purification of polyvinyl alcohol, can solve the problems of complex process, high energy consumption, increased cost and the like, and achieve the effect of reducing cost

Active Publication Date: 2011-04-20
CHINA PETROCHEMICAL CORP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method can effectively prepare high-purity PVA products without changing the previous preparation process, but when performing ion exchange, the PVA must be dissolved (or partially dissolved) in water first, and after the metal ions are removed, the PVA must be dissolved in water. To re-precipitate the dissolved PVA, the energy consumption is high, the process is complicated, and the cost increases significantly, so there are certain difficulties in industrial applications.
[0008] In addition, the above-mentioned methods usually need to make relatively large adjustments to the relatively mature and perfect industrial preparation of PVA technology, which has great difficulties in practical application.

Method used

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  • Purification method of polyvinyl alcohol
  • Purification method of polyvinyl alcohol
  • Purification method of polyvinyl alcohol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Example 1: Disperse 25 parts of polyvinyl alcohol particles (the degree of polymerization is 2400, and the degree of alcoholysis is 99%) in 75 parts of methanol, stir at 50°C for 20min, then filter and separate the polyvinyl alcohol, at 60°C Dry to obtain high-purity polyvinyl alcohol. According to the national standard (GB 12010.7-89), the ash content of polyvinyl alcohol before and after treatment was measured, and the results showed that the ash content of polyvinyl alcohol (polymerization degree: 2400, alcoholysis degree: 99%) dropped from 0.27% before treatment to 0.064%.

Embodiment 2

[0027] Example 2: disperse 30 parts of polyvinyl alcohol particles (the degree of polymerization is 2400, the degree of alcoholysis is 99%) into the mixed solution of 70 parts of methanol and water (methanol: water = 5: 1, by volume ratio) , stirred at 40°C for 30 minutes, then filtered to separate polyvinyl alcohol, and dried at 60°C to obtain high-purity polyvinyl alcohol. According to the national standard (GB 12010.7-89), the ash content of polyvinyl alcohol before and after treatment was measured, and the results showed that the ash content of polyvinyl alcohol (polymerization degree: 2400, alcoholysis degree: 99%) dropped from 0.27% before treatment to 0.043%.

Embodiment 3

[0028] Example 3: Disperse 30 parts of polyvinyl alcohol (the degree of polymerization is 1700, and the degree of alcoholysis is 88%) into 70 parts of ethyl acetate, stir at 60°C for 10min, then filter and separate the polyvinyl alcohol, 60°C Under drying, high-purity polyvinyl alcohol is obtained. According to the national standard (GB 12010.7-89), the ash content of polyvinyl alcohol before and after treatment was measured, and the results showed that the ash content of polyvinyl alcohol (polymerization degree: 1700, alcoholysis degree: 88%) dropped from 0.19% before treatment to 0.013%.

[0029] Certainly, in this example, water can also be used as a solvent to carry out purification treatment to polyvinyl alcohol.

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Abstract

The invention relates to a purification method of polyvinyl alcohol obtained by alkali catalysis on polyvinyl acetate. In the method, a solution in which polyvinyl alcohol is undissolved or difficult to be dissolved while residues of polyvinyl alcohol are soluble is taken as a solvent, and purification on polyvinyl alcohol is carried out. The invention requires no modification on the traditional mature and complete industrialized PVA preparation process, thus being beneficial to implementation of industrialization, and ash content of the polyvinyl alcohol purified by the method in the invention is close to or less than 0.1%; and the solvent required in the process for preparing polyvinyl alcohol from polyvinyl acetate by hydrolysis or the product obtained by the process is taken as a solvent for purification treatment of polyvinyl alcohol, the produced waste liquor can be merged into the original waste liquor recovery and purification system, the cost is effectively reduced, and the separation of the polyvinyl alcohol after being purified is convenient.

Description

technical field [0001] The invention relates to a purification method of polyvinyl alcohol, which is particularly suitable for the purification method of polyvinyl alcohol prepared from polyvinyl acetate catalyzed by alkali method. Background technique [0002] Since polyvinyl alcohol (hereinafter referred to as PVA) is non-toxic and harmless, has good water solubility and good biocompatibility, it has many special uses in the fields of medicine and life, and the demand for polyvinyl alcohol at home and abroad Both are large (Uhrich K E, Canizarro S M, et al. Polymeric systems for control drug release [J]. ChemRev, 1999, 99: 3181-3198). Polyvinyl alcohol is mainly obtained by hydrolyzing polyvinyl acetate by acid method or alkali method. Among them, acid hydrolysis is less used in industrial production due to many disadvantages, such as slow reaction speed, easy to corrode equipment, and easy coloring of products; the alkali hydrolysis of polyvinyl acetate with sodium hydro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F16/06C08F6/00
Inventor 江龙廖永康淡宜何灵芝
Owner CHINA PETROCHEMICAL CORP
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