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Straight-chain dialdehyde-modified polyvinyl alcohol and preparation method and application thereof

A technology of polyvinyl alcohol and dialdehyde, which is applied in the field of straight-chain dialdehyde modified polyvinyl alcohol and its preparation, can solve the problems of excessively wide molecular weight distribution, poor foam suppression performance, and high economic cost, and achieve the goal of inhibiting chlorine Foaming during ethylene polymerization, suppression of foaming, and short process time

Active Publication Date: 2019-04-19
CHINA PETROCHEMICAL CORP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chinese patent CN151927A discloses that a modified polyvinyl alcohol dispersant is prepared by adding polyvinyl alcohol resin to a metal salt and other additives at a temperature of 175-250 ° C in an extruder for 1-15 minutes by melt kneading; the method Medium-modified polyvinyl alcohol will undergo severe dehydration and decarboxylation reactions, and at the same time, partial decomposition reactions will occur, the economic cost is high, the color of the obtained product is darker, and insoluble substances are produced, and the product quality is poor
Chinese patent CN101747459A discloses that the modified polyvinyl alcohol dispersant is obtained through bulk polymerization or solution polymerization for 8-14 hours, and then undergoes subsequent alcoholysis, drying and other processes to obtain a modified polyvinyl alcohol dispersant; The anti-foaming performance of the product is relatively poor; the modified polyvinyl alcohol product prepared by this method is also only used as an auxiliary dispersant in the suspension polymerization of vinyl chloride
Due to the high technical difficulty, there is currently no polyvinyl alcohol with good color hue, excellent foam suppression, colloid retention, and dispersibility as a dispersant and its preparation technology disclosure

Method used

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  • Straight-chain dialdehyde-modified polyvinyl alcohol and preparation method and application thereof
  • Straight-chain dialdehyde-modified polyvinyl alcohol and preparation method and application thereof
  • Straight-chain dialdehyde-modified polyvinyl alcohol and preparation method and application thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0035]100 parts by weight of vinyl acetate, 100 parts by weight of methanol, 3.0 parts by weight of adipaldehyde and 0.072 parts by weight of azobisisobutyronitrile (AIBN) were added to the polymerization reactor. After replacing with nitrogen, the temperature began to rise, and the polymerization reaction began to count when there was reflux at about 60° C., and ended after 5 hours. Unreacted vinyl acetate is then removed to obtain a methanol solution of polyvinyl acetate. To the obtained polyvinyl acetate methanol solution (concentration 32-35%), add 10 millimoles of sodium hydroxide in methanol per mole of vinyl acetate unit. Carry out hydrolysis at 40°C for 35 minutes, add glacial acetic acid equivalent to sodium hydroxide to terminate the reaction, and obtain a methanol solution of PVA resin, and send the methanol solution of PVA resin evenly into a centrifuge protected by nitrogen through a screw pump for solidification Liquid separation, to obtain PVA resin (1# degree ...

Embodiment 2

[0037] 100 parts by weight of vinyl acetate, 80 parts by weight of methanol, 3.5 parts by weight of adipaldehyde and 0.072 parts by weight of azobisisobutyronitrile (AIBN) were added to the polymerization reactor. After replacing with nitrogen, the temperature began to rise, and the polymerization reaction began to count when there was reflux at about 60° C., and ended after 5 hours. Unreacted vinyl acetate is then removed to obtain a methanol solution of polyvinyl acetate. To the resulting polyvinyl acetate methanol solution (concentration 32-35%), add 10 millimoles of sodium hydroxide in methanol per mole of vinyl acetate unit. Hydrolyze at 40° C. for 35 minutes, add glacial acetic acid equivalent to sodium hydroxide to terminate the reaction, and obtain PVA resin (2# degree of polymerization 731, degree of alcoholysis 71.97 mol%) after centrifugation. The obtained PVA resin was dried in a vacuum drying oven at 110° C. for 2 hours under a vacuum degree of −0.01 MPa to obtai...

Embodiment 3

[0039] 100 parts by weight of vinyl acetate, 60 parts by weight of methanol, 4.5 parts by weight of adipaldehyde and 0.070 parts by weight of azobisisobutyronitrile (AIBN) were added to the polymerization reactor. After replacing with nitrogen, the temperature began to rise, and the polymerization reaction began to count when there was reflux at about 60° C., and ended after 5 hours. Unreacted vinyl acetate is then removed to obtain a methanol solution of polyvinyl acetate. To the resulting polyvinyl acetate methanol solution (concentration 32-35%), add 10 millimoles of sodium hydroxide in methanol per mole of vinyl acetate unit. Carry out hydrolysis at 40°C for 35 minutes, add glacial acetic acid equivalent to sodium hydroxide to terminate the reaction, and obtain a methanol solution of PVA resin, and send the methanol solution of PVA resin evenly into a centrifuge protected by nitrogen through a screw pump for solidification The liquid was separated to obtain PVA resin (3# ...

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Abstract

The invention provides a straight-chain dialdehyde-modified polyvinyl alcohol. By using straight-chain dialdehyde for modification of polyvinyl alcohol, the prepared modified polyvinyl alcohol is usedas a main dispersing agent for suspension polymerization of vinyl chloride, especially has a good dispersion effect when being used as a main dispersing agent for suspension polymerization of vinyl chloride, can effectively inhibit foaming in the vinyl chloride polymerization process, and has good rubber retention performance and dispersion performance. A polyvinyl chloride product with excellentperformance and uniform particle size distribution and having viscosity number of 107-112ml / g, apparent density of 0.45-0.50g / ml and plasticizer absorption of 20% and above can be prepared. The preparation method is simple, has short process time, requires no large equipment, and is suitable for industrial production.

Description

technical field [0001] The invention relates to modified polyvinyl alcohol, in particular to a straight-chain dialdehyde-modified polyvinyl alcohol and its preparation method and application. Background technique [0002] Polyvinyl alcohol (PVA), as the most commonly used dispersant for vinyl chloride suspension polymerization, plays a vital role in the performance index of vinyl chloride suspension polymerization and polyvinyl chloride products. However, with the application of large-scale polymerization reactors equipped with condensers in the vinyl chloride industry, the pressure near the reflux condenser drops due to the condensation of vinyl chloride monomer vapor, resulting in wet foam caused by dispersants and composed of PVC particles dry foam, resulting in a reduction in the effective volume in the polymerization vessel, a decrease in production efficiency, and fouling. Therefore, it is necessary to develop new polyvinyl alcohol as a dispersant. [0003] In the de...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F118/08C08F8/12C08F2/20C08F114/06
CPCC08F2/20C08F8/12C08F114/06C08F118/08
Inventor 侯双燕陆春因郭永松李永江
Owner CHINA PETROCHEMICAL CORP
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