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What is the use of PVA film?

What is the use of PVA film?

Polyvinyl alcohol film is a green and environmentally friendly functional material that is made of Polyvinyl alcohol as the main body, added with modifiers and other additives, processed by a special process, and can be completely degraded by microorganisms in the soil. It can be degraded into carbon dioxide and water in a short time, and has the effect of improving the land.

This passage is going to talk about the followings of Polyvinyl alcohol:

(1) Definition of polyethylene film

(2) Chemical traits of polyethylene film

(3) Excellent performance of PVA film

 

(1) Definition of polyethylene film

Polyvinyl alcohol (PVA) is a water-soluble polymer, which is characterized by good density, high crystallinity, strong adhesion, flexible and smooth film, oil and solvent resistance, abrasion resistance, and good gas barrier properties. And the water resistance with special treatment, it has a wide range of uses.

Polyvinyl alcohol is non-toxic, tasteless and harmless to the human body, has good affinity with the natural environment, does not accumulate, and does not pollute.

The biggest advantage of Polyvinyl alcohol film is water solubility, and the biggest disadvantage is poor water resistance. The poor water resistance is due to the hydrophilic hydroxyl (-OH) in the molecule. If the hydroxyl group can be properly blocked and the water resistance group can be attached, the water resistance of the PVA film can be improved. PVA contains hydroxyl groups, which can cause all the typical reactions of polyols. If appropriate polycondensate is selected, it can be appropriately cross-linked with the hydroxyl groups in PVA when the amount of addition is not large, so that PVA can form a strong three-dimensional structure. Stabilizes the air tightness of PVA under wet conditions and improves water resistance.

 

(2) Chemical traits of polyethylene film

Polyvinyl alcohol film (referred to as PVA), the density of the Polyvinyl alcohol film is 1.26-1,29g/cm cubic, the refractive index is 1.52, and it emits white light after ultraviolet radiation. It has high water absorption and can be dissolved when immersed in water. The moisture content of the fiber can reach 30%-50%, and the moisture content can reach 4.5% under the environment of 65% RH and 25 ℃. It can permeate water vapor, but is difficult to permeate alcohol vapor, let alone organic solvent vapor, inert gas and hydrogen. The barrier properties of Polyvinyl alcohol film are even better than that of vinylidene chloride film.

 

 

(3) Excellent performance of PVA film

Polyvinyl alcohol as a protective film has the following advantages:

1. The Polyvinyl alcohol protective film has proper adhesion to the mirror-finished metal surface and various plastic surfaces.

2. The Polyvinyl alcohol aqueous solution has great film-forming properties, and the resulting film is strong, so it has a great protective effect on the painted surface, and it is easy to peel off when not needed. In the case of using partial alcoholysis Polyvinyl alcohol, it can be easily washed off with water.

3. Oxygen, hydrogen sulfide, etc. have low permeability to gases that corrode metals, so it has a great anti-corrosion effect on metal processing surfaces.

The protective film generally uses PVA-117, but for the purpose of washing and removing, PVA-217, 2050 can be used

The method of use is to add 2-10% glycerol and some necessary antifoaming agents to the water solution of about 15% polyethylene drunk to prepare a coating solution.

Spray paint guns, roller coaters and curtain flow coaters are used for coating, and the amount of cloth is more than 20 g/m2 of solid content.

 

 

 


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