A kind of modified polyvinyl alcohol and preparation method thereof

A polyvinyl alcohol and modification technology, applied in the field of vinyl-modified polyvinyl alcohol and its preparation, can solve the problems of difficulty in obtaining emulsion polymerization, high surface tension, no water resistance, etc., and achieve good water solubility and viscosity stability. Good, water resistance improvement effect

Active Publication Date: 2016-04-27
CHINA PETROCHEMICAL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Partially alcoholyzed PVA is generally used in ordinary process formulas, but if the emulsion is required to have better water resistance, it is not suitable to use partially alcoholyzed PVA, because partially alcoholyzed PVA itself has no water resistance
In order to improve water resistance, it is required to use completely alcoholyzed PVA, but the surface tension of the completely alcoholyzed PVA aqueous solution is high, and it is difficult to obtain stable emulsion polymerization

Method used

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  • A kind of modified polyvinyl alcohol and preparation method thereof
  • A kind of modified polyvinyl alcohol and preparation method thereof
  • A kind of modified polyvinyl alcohol and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] The preparation of vinyl modified polyvinyl alcohol, according to the following steps:

[0050] 1), initial feeding

[0051] Add 84-87 parts of soft water, 0.04-0.06 parts of reducing agent sodium bisulfite, and 0.4-0.6 parts of emulsifier sodium vinyl sulfonate into the high-pressure stainless steel reaction kettle, tighten the lid, and stir evenly at room temperature at a speed of 150-210rpm. Stand still for 25-35 minutes;

[0052] 2) Replacement in the kettle

[0053] Use 8~12bar N 2 Replace twice, and then replace twice with 8-12bar ethylene, each replacement lasts 3-5min;

[0054] 3) Adding monomers and oxidants for polymerization

[0055] After replacing the inside of the kettle, use a high-pressure metering pump to add 20 to 25 parts of vinyl acetate monomer at full speed, and feed in ethylene monomer to control the pressure in the kettle to 3 to 10 bar. Add 0.05-0.06 parts of oxidant ammonium persulfate to the high-pressure metering pump at full speed. Coun...

Embodiment 2

[0074] A kind of preparation method of vinyl-modified polyvinyl alcohol, what this preparation method adopted is emulsion polymerization; It comprises the following steps:

[0075] 1. Dissolve 0.08 parts by weight of sodium bisulfite in water and 0.6 parts by weight of sodium vinylsulfonate in water and add them together into a 10L high-pressure reactor. The total amount of water used is 82 parts. Tighten the lid of the feeding port and test for leaks Pressure test, start stirring, set the speed at 210rpm, stir evenly, and let stand for 35min;

[0076] 2. Use 12bar N 2 Substitute twice, and then replace twice with 12bar ethylene, and each replacement lasts for 3 minutes;

[0077] 3. Use a high-pressure metering pump to add 40 parts by weight of vinyl acetate monomer at full speed, feed the vinyl monomer, set the pressure in the kettle to 3 bar, and when the temperature in the kettle reaches 65°C, dissolve 0.045 parts by weight of ammonium persulfate in water , use a high-pre...

Embodiment 3

[0085] A kind of preparation method of vinyl modified polyvinyl alcohol, it carries out according to the following steps:

[0086] 1. Dissolve 0.02 parts by weight of sodium bisulfite in water and 0.2 parts by weight of sodium vinylsulfonate in water and add them together into a 10L high-pressure reactor. The total amount of water used is 88 parts. Tighten the lid of the feeding port and test for leaks Test the pressure, turn on the stirring, set the speed to 150rpm, stir evenly, and let stand for 30min;

[0087] 2. Use 8bar N 2 Replace twice, and then replace twice with 8bar ethylene, and each replacement lasts for 4 minutes;

[0088] 3. Use a high-pressure metering pump to add 10 parts by weight of vinyl acetate monomer at full speed, feed the vinyl monomer, set the pressure in the kettle to 20 bar, and when the temperature in the kettle reaches 55°C, dissolve 0.065 parts by weight of ammonium persulfate in water , use a high-pressure metering pump to pump into the kettle ...

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Abstract

The invention discloses a modified polyvinyl alcohol (PVA). Chemical structure of the modified polyvinyl alcohol (PVA) is represented by a formula the invention, wherein R1 is used for representing CnH<2n+1>, n=0-18, or is used for representing phenyl, R2 is used for representing H or alkyl, R3 is used for representing Na or K, c=0.2-2%(mol), d=3-15%(mol), and a / (a+b)=97-99%(mol). The vinyl modified polyvinyl alcohol can be used as a polymerization auxiliary agent for emulsion polymerization; and is capable of avoiding disadvantages of common PVA that water resistance is poor, and polymerization system is unstable. Water resistance is increased significantly; water solubility is high; requirements on polymerization auxiliary agents are satisfied completely; and the vinyl modified polyvinyl alcohol can be used as polymerization auxiliary agent for improving stability of the polymerization system, and improving particle size distribution greatly.

Description

technical field [0001] The invention relates to a polymerization assistant used in emulsion polymerization of vinyl acetate, VAE, etc., in particular to a vinyl-modified polyvinyl alcohol and a preparation method thereof. Background technique [0002] Polyvinyl alcohol (PVA) is an important emulsion polymerization assistant with excellent performance. It is usually used as a protective colloid in the emulsion polymerization of vinyl acetate, VAE, etc. Partially alcoholyzed PVA is generally used in ordinary process formulas, but if the emulsion is required to have better water resistance, it is not suitable to use partially alcoholyzed PVA, because partially alcoholyzed PVA itself has no water resistance. In order to improve water resistance, it is required to use completely alcoholyzed PVA, but the surface tension of completely alcoholyzed PVA aqueous solution is high, and it is difficult to obtain stable emulsion polymerization. Contents of the invention [0003] The pur...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F216/06C08F228/02C08F2/26C08F218/08C08F8/00
Inventor 窦玉芹黎园吴永忠胡腊梅任文革廖永康王培发何灵芝
Owner CHINA PETROCHEMICAL CORP
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