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A kind of polyvinyl alcohol and its preparation method and application

A polyvinyl alcohol and vinyl technology, applied in the field of organic polymer compounds, can solve the problems affecting the COD value of wastewater discharged from PVC factories, the absorption capacity of plasticizers cannot reach the ideal, and the effect of auxiliary dispersants cannot be fully exerted, etc., to achieve shortening Plasticizing time, easy industrial production, and excellent processing performance

Active Publication Date: 2018-11-06
CHINA PETROCHEMICAL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, polyvinyl alcohol with a degree of alcoholysis not higher than 60mol% is poor in water solubility, so this type of product can only be provided to users as solid particles or dissolved in water / alcohol solution. During the suspension polymerization of vinyl chloride, The use of solid particle materials will lead to poor operability, and the effect as an auxiliary dispersant cannot be fully exerted. When using water / alcohol solvent solution products, alcohol solvents will pollute the environment and affect the COD value of wastewater discharged from PVC plants.
In order to solve such problems, there have been researches on introducing modified PVA aqueous solutions such as amine groups, carboxyl groups, and sulfonic acid groups into the branched chains as auxiliary dispersants. However, when ionic modified PVA is used, it will change the vinyl chloride suspension polymerization system. The pH value of the pH value affects the stability of the system, so that the characteristics of the dispersant cannot be effectively exerted, so that the porosity of the prepared vinyl polymer is not high, and the pore distribution is not uniform. Plasticizer absorption capacity is not ideal
In addition, there is also polyvinyl alcohol modified by copolymerization of vinyl acetate and other vinyl ethers. Although the polyvinyl alcohol is well soluble in water, when it is made into an aqueous solution dispersant product, the viscosity stability is excellent, but the production cost is significantly increased. , and the production process is complicated, the obtained modified polyvinyl alcohol is still high in viscosity when it is formulated into a high-concentration aqueous solution product, which makes its operability poor in application

Method used

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  • A kind of polyvinyl alcohol and its preparation method and application
  • A kind of polyvinyl alcohol and its preparation method and application
  • A kind of polyvinyl alcohol and its preparation method and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] In the presence of 2.0 parts of AIBN, 100 parts of vinyl acetate are solution polymerized in a mixed solvent of 100 parts of methanol and 40 parts of acetone. The polymerization temperature is 60 ° C. When the polymerization reaction is over, switch to blow out the residual sheet to obtain polyvinyl acetate Resin, take a part of polyvinyl acetate resin and adjust it into a methanol solution with a concentration of 46wt%, and then carry out alcoholysis with a methanol solution with a concentration of 40g / L sodium hydroxide. Mole of glacial acetic acid terminates the reaction, obtains polyvinyl alcohol with low degree of polymerization and low degree of alcoholysis of the present invention, and its degree of polymerization is 218, and degree of alcoholysis is 58.4 (mol / mol)%, and its concentration is that the cloud point of the aqueous solution of 4wt% is At 12.5°C, the viscosity of the aqueous solution with a concentration of 40wt% at 25°C is 1100mPa.s, and the viscosity ...

Embodiment 2

[0044] The aqueous solutions made of the polyvinyl alcohol with low degree of polymerization and low degree of alcoholysis obtained in Example 1 are used as auxiliary dispersants for suspension polymerization of vinyl polymers; for suspension polymerization of vinyl chloride: in an autoclave Add 180 parts of soft water, add 0.05 parts of the above-mentioned auxiliary dispersant while stirring at 400 rpm, 0.06 parts of polyvinyl alcohol with an alcoholysis degree of 70mol% and a polymerization degree of 800, 0.2 parts of lauryl peroxide, and then add 150 parts of vinyl chloride mono Body, when the temperature is raised to 60 ° C for suspension polymerization, the polyvinyl chloride resin is obtained. Using the resin obtained in Example A1, the apparent densities are 0.54g / ml and 0.51g / ml respectively, and the number of fish eyes is 4 / 400cm 2 , 6pcs / 400cm 2 , plasticizer absorption rate is 25g / 100g, 27g / 100g, 250um sieve residue is less than 2.0, residual vinyl chloride is 1.8m...

Embodiment 3～8

[0059] The second solvent in embodiment 3-4 in table 1 is toluene, the second solvent in embodiment 5-6 is ethanol, the second solvent in embodiment 7-8 is Virahol; In embodiment 5-8 The initiator is respectively Perkadox16, EHP, peroxypivalic acid-pivalic acid ester, dipropyl peroxydicarbonate, and the initiator in other examples and comparative examples is AIBN; Be sodium hydroxide; The modifying agent in the comparative example 2-4 is respectively acetaldehyde, valeraldehyde and dodecyl mercaptan. The modifiers in Examples 3-4 are acetaldehyde and valeraldehyde respectively; the second monomer in Examples and Comparative Examples is itaconic acid. Using the relevant parameters described in Tables 1 and 2 below, according to the preparation methods of Examples 1 and 2, the aqueous solution of polyvinyl alcohol auxiliary dispersant with low degree of polymerization and low degree of alcoholysis, and the polyvinyl chloride particle product were prepared.

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Abstract

The invention provides polyvinyl alcohol, which is characterized by having the average degree of polymerization in a range of 50-500, the alcoholysis degree in a range of 30-65 mol%, and the viscosity no more than 1500 mPa*s. Polyvinyl alcohol is prepared into an aqueous solution, which is taken as an auxiliary dispersant for suspension polymerization of vinyl polymers. The cloud point of an aqueous solution, the concentration of which is 5 wt%, (that is, a polyvinyl alcohol aqueous solution of 5 wt%), is no less than 1 DEG C and less than 15 DEG C. The viscosity measured at 25 DEG C of an aqueous solution, the concentration of which is 40 wt%, is no more than 1500 mpa*s. Gel and layering don't appear in an aqueous solution, the concentration of which is in a range of 30wt%-50wt%, in at least one year, so that the aqueous solution is extremely excellent in stability.

Description

technical field [0001] The invention belongs to the field of organic macromolecular compounds, in particular to polyvinyl alcohol and a preparation method thereof, especially as an auxiliary dispersant for suspension polymerization of vinyl polymers. Background technique [0002] Generally, polyvinyl alcohol with a degree of polymerization not higher than 500 and a degree of alcoholysis not higher than 60 mol% is widely used as an auxiliary dispersant for suspension polymerization of vinyl compounds (especially vinyl chloride). However, polyvinyl alcohol with a degree of alcoholysis not higher than 60mol% is poor in water solubility, so this type of product can only be provided to users as solid particles or dissolved in water / alcohol solution. During the suspension polymerization of vinyl chloride, The use of solid particle materials will lead to poor operability, and the effect as an auxiliary dispersant cannot be fully exerted. When using water / alcohol solvent solution pr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F118/08C08F2/06C08F8/00C08F218/08C08F114/06C08F2/20
Inventor 吕惠霞胡腊梅侯双燕吴永忠廖永康
Owner CHINA PETROCHEMICAL CORP
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