HEADING 39.05 - POLYMERS OF VINYL ACETATE OR OF OTHER VINYL ESTERS IN PRIMARY FORMS; OTHER VINYL POLYMERS IN PRIMARY FORMS.

38 COMMODITIES

-Polyvinyl acetate :

3905.12- - In aqueous dispersion

3905.19- - Other

-Vinyl acetate copolymers :

3905.21- - In aqueous dispersion

3905.29- - Other

3905.30- Polyvinyl alcohol whether or not containing unhydrolysed acetate groups

- Other :

3905.91- - Copolymers

3905.99- - Other

This heading covers all vinyl polymers other than those of heading 39.04. A vinyl polymer is one whose monomer has the formula 39.11).

Polymers of vinyl acetate or of other vinyl esters of which polyvinyl acetate is by far the most important are not suitable for the manufacture of articles as they are too soft and elastic. They are generally used for the preparation of lacquers paints adhesives finishing or impregnating agents for textiles etc. Solutions and dispersions (emulsions and suspensions) of polyvinyl acetate are used e.g. as adhesives.

Polyvinyl alcohol is usually prepared by the hydrolysis of polyvinyl acetate. Polyvinyl alcohols are available in a number of grades depending upon the content of unhydrolysed vinyl acetate groups. These are excellent emulsifiers and dispersing agents and are used as protective colloids adhesives binders and thickeners in paints pharmaceuticals and cosmetics and in textiles. Fibres produced from polyvinyl alcohols are suitable for making underwear blankets clothing etc.

Polyvinyl acetals can be prepared by reacting polyvinyl alcohol with an aldehyde such as formaldehyde or butyraldehyde or by reacting polyvinyl acetate with an aldehyde.

Other vinyl polymers include polyvinyl ethers polyvinylcarbazole and polyvinylpyrrolidone.

For the classification of polymers (including copolymers) chemically modified polymers and polymer blends see the General Explanatory Note to this Chapter.