PREPARATION OF POLYURETHANE/ ACRYLIC HYBRID DISPERSIONS.

Aqueous polyurethane acrylic hybrid resin dispersion, which can be used for coatings on wood, metal, ABS, masonry, leather, paper, fabric etc.

Example

In a 4 neck round bottom flask equipped with agitator, condenser, addition funnel, thermometer, nitrogen purge, and water bath is taken.

To this reactor is charged:

x1 gms of Polyester polyol/ Polyether polyol (OH value 85 - 125),

x2 gms of trimethylolpropane,

x3 gms of 2,2-dimethylolpropionic acid,

x4 gms of dibutyltin dilaurate,

x5 gms of N-methylpyrrolidone,

x6 gms of acetone.

Heat these contents of flask to 75° C under nitrogen purging for 30 minutes. When temperature reaches to 75° C start adding:

x7 gms of isophorone diisocyanate

drop wise to the contents of the flask within 30 - 40 minutes.

The temperature of reaction mixture is maintained at 80 ° C until required isocyanate content is achieved.

The resulting prepolymer is cooled to 50° C. Add:

x8 gms of triethylamine to this prepolymer under vigorous stirring. Prepare mixture of monomers i.e. :

x9 gms of butyl acrylate,

x10 gms of methylmethacrylate &

x11 gms of styrene.

Add this monomer mixture to neutralized prepolymer slowly under stirring. Add:

x12 gms of deionized water to this prepolymer / monomer mixture slowly under high speed stirring within 20 - 30 minutes.

Prepare mixture of:

x13 gms of (2,2-azobisisobutyronitrile) &

x14 gms N-methylpyrrolidone.

Add this mixture to the above dispersion within 10 minutes.

Make solution of:

x15 gms of ethylenediamine &

x16 gms of deionized water.

Add this solution to the dispersion quickly & stir this for 10 - 15 minutes.

Carry out free radical polymerization of monomers in presence of Polyurethane dispersion at 75° C till complete conversion of monomers takes place.