Use and application of polyvinyl alcohol

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[Abstract]:

Polyvinyl alcohol (PVA), a white powder, is a water-soluble polymer with a wide range of applications. Its properties are between plastics and rubber.
Because of PVA has a unique strong adhesion and f

Polyvinyl alcohol (PVA), a white powder, is a water-soluble polymer with a wide range of applications. Its properties are between plastics and rubber.

Because of PVA has a unique strong adhesion and film flexibility, smoothness, oil resistance, solvent resistance, protective colloid, gas block, wear resistance, and the special treatment with water resistance, therefore, except for fiber raw material has been used in the production of coatings, adhesives, paper processing agent, emulsifier, dispersant, film and other products, range of application in textile, food, medicine, architecture, wood processing, paper making, printing, agriculture, steel and polymer chemical industry, etc.

Product performance: polyvinyl alcohol resin series products are white solids, appearance is divided into flocculent, granular, powder three kinds; Non-toxic tasteless, pollution-free, can be dissolved in 80-90 ℃ water. The aqueous solution has good adhesion and film-forming property. Oil, lubricants and most organic solvents such as hydrocarbons; It has the chemical properties of esterification, etherification and acetal of long chain polyols.

Application: mainly used in textile industry warp sizing, fabric finishing agent, vinylon fiber raw materials; Construction decoration industry 107 glue, interior and exterior wall paint, adhesive; Chemical industry used as polymerization emulsifier, dispersant and polyvinyl formal, acetaldehyde, butyraldehyde resin; Paper industry as paper binder; Agricultural applications: soil improver, pesticide adhesion and polyvinyl alcohol film; Also can be used in daily cosmetics and high-frequency quenching agent.

Usage: polyvinyl alcohol resin series products can be dissolved in hot water below 95℃, but due to the degree of polymerization, degree of alcoholysis, different alcoholysis methods and other differences in the dissolution time, temperature, so in the use of different brands of polyvinyl alcohol resin, the dissolution method and time need to be explored. When dissolved, stirring handing this product full swelling slowly add about 20 ℃ cold water, dispersion, and the transgression of volatile materials (do not join in more than 40 ℃ water directly to dissolve the product, to avoid package and skin to dissolve the endogenous phenomenon), and then heat up to about 95 ℃ dissolve faster, and insulation 2 ~ 2.5 hours, until the solution is no longer contains small particles, after 28 mesh, stainless steel filter impurities can be set aside.

The stirring speed is 70 ~ 100 RPM. When the temperature is raised, jacket, water bath and other indirect heating methods can be adopted, and water vapor can also be directly heated. But, cannot use open flame to heat directly, lest local overheat and decompose, if do not have agitator, usable steam blows in with tangent direction method, carry on dissolving.

The concentration of aqueous solution of polyvinyl alcohol resin series is generally below 12 ~ 14%. The concentration of aqueous solution of polyvinyl alcohol resin products with low alcoholysis is generally about 20%.

Test whether the product is completely dissolved: take out a small amount of solution, add 1 ~ 2 drops of iodine solution, if there is a blue pellet transparent body, indicating that it has not been completely dissolved, if the color can be evenly diffused, indicating that it has been completely dissolved.

Solution storage: anticorrosion: if long-term storage, the water in the aqueous solution will corrupt, but will not affect the performance of the product, at this time should be added 0.01-0.05% (with P

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