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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 polyvinyl alcohol and its preparation, can solve the problems of insufficient PVA dispersibility, unfavorable stabilization of the viscosity of PVA solution, influence on the effect of auxiliary dispersants, etc. The effect of forming time, excellent resin processability, and regular shape

Active Publication Date: 2018-05-11
CHINA PETROCHEMICAL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional polyvinyl alcohol used as an auxiliary dispersant has a low block characteristic coefficient (η), and its segment distribution is more orderly, and this structure of polyvinyl alcohol is easier to form hydrogen bonds in its molecule or between molecules, Due to the existence of strong hydrogen bonds, the viscosity of the PVA solution will increase, which is not conducive to the stability of the viscosity of the PVA solution, thus affecting its use as an auxiliary dispersant, so that the dispersibility of PVA cannot be fully exerted.
In addition, due to poor water solubility or high solution viscosity, this type of auxiliary dispersant is often a product of water / alcohol mixed in a certain proportion as a solvent, which not only increases the cost of the auxiliary dispersant, but also deteriorates its operability and use environment.

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

[0028] In the presence of 1.65 parts of AIBN, 100 parts of vinyl acetate are solution-polymerized in 150 parts of methanol. The polymerization temperature is 60°C. When the polymerization reaction is over, switch and blow out the residual sheet to obtain polyvinyl acetate resin. Take a part of polyvinyl acetate Resin is adjusted into the methanol solution that concentration is 45wt%, carrying out alcoholysis with the p-toluenesulfonic acid methanol solution of 30wt% with concentration, when alcoholysis degree reaches required value, spray with the methanol solution of 40g / L sodium hydroxide The reaction is terminated by leaching to obtain polyvinyl alcohol with low degree of polymerization and low degree of alcoholysis of the present invention. The degree of polymerization is 380, the degree of alcoholysis is 42.3 (mol / mol), the degree of block is 0.80, and its concentration is 34.5wt% alcohol The measured viscosity of the solution at 25°C is 98mPa.s, and the viscosity stabilit...

Embodiment 2

[0044] The alcohol solution with a concentration of 34.5 wt% prepared by the polyvinyl alcohol with low degree of polymerization and low degree of alcoholysis prepared in Example 1 is used as an auxiliary dispersant for suspension polymerization of vinyl polymers; it is used for suspension polymerization of vinyl chloride : Add 200 parts of soft water in the autoclave, add 0.08 part of the above-mentioned auxiliary dispersing agent while stirring at 350rpm, alcoholysis degree is 80mol% polyvinyl alcohol 0.03 part, 0.2 part of lauryl peroxide, then add 150 parts of vinyl chloride monomer, when the temperature is raised to 60°C, carry out suspension polymerization to obtain polyvinyl chloride resin. Using the resin obtained in Example B1, its apparent density is 0.53g / ml, and the number of fish eyes is 6 / 400cm 2 , the absorption rate of plasticizer is 27g / 100g, the 250um sieve residue is less than 2.0, and the residual vinyl chloride is 1.6mg / Kg, meeting the requirements of inte...

Embodiment 3-8

[0057] Embodiment 3-8, comparative example 1-4

[0058] A3-A7 in Table 1: medium chain transfer agents are respectively vinyl polyoxyethylene ether, isopropanol, acetaldehyde, valeraldehyde, ethanol, the medium chain transfer agents of comparative examples 2-3 are acetaldehyde, dodecyl sulfide Alcohol; Catalyst in A3-A8 is sulfuric acid, hydrochloric acid, benzenesulfonic acid, 2-methyl-5-propanebenzenesulfonic acid, 1,5-naphthalene disulfonic acid, 2,7-benzenedisulfonic acid respectively; Comparative example Catalyst is sodium hydroxide among 1-4; The initiator among the embodiment A3-A5 and comparative example 2-4 is AIBN, and among the embodiment A6-A8, initiator is respectively dipropyl peroxydicarbonate, EHP, Peroxypivalic acid-pivalic acid ester, comparative example 1 initiator is peroxypivalic acid-pivalic acid ester. Using the relevant parameters described in Tables 1 and 2 and in combination with the conventional production process, according to the methods of Exampl...

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Abstract

The invention provides a polyvinyl alcohol, which is characterized in that the average polymerization degree is not higher than 500, the block degree is 0.50-0.85, and the alcoholysis degree is 35mol%-65mol%. The polyvinyl alcohol with low degree of polymerization, low degree of alcoholysis and low viscosity of the present invention has particularly excellent viscosity stability, and has strong dispersion ability and good dispersion stability for monomer oil droplets when used in suspension polymerization of vinyl polymers. It is not affected by the polymerization conditions of vinyl compounds; the porosity distribution of the prepared vinyl polymers is uniform, the porosity is high, and the removal of residual monomers is good. Excellent plastics absorption capacity, excellent processing performance, and can shorten the plasticizing time and reduce the number of fish eyes.

Description

technical field [0001] The invention relates to a polyvinyl alcohol and a preparation method thereof, in particular to a polyvinyl alcohol auxiliary dispersant for vinyl polymer suspension polymerization. Background technique [0002] In the process of vinyl monomer suspension polymerization, in order to better disperse the monomer droplets and prevent the coalescence of the early droplets and the middle and later polymerization particles, the system often adds the main dispersant and auxiliary dispersant, and the auxiliary dispersant is usually A hydroalcoholic solution of polyvinyl alcohol with a low degree of polymerization and low degree of alcoholysis, and a resin with high oil absorption and porosity can be obtained by using the polyvinyl alcohol. The traditional polyvinyl alcohol used as an auxiliary dispersant has a low block characteristic coefficient (η), and its segment distribution is more orderly, and this structure of polyvinyl alcohol is easier to form hydroge...

Claims

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Application Information

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