Method of producing super soft polyacrylate-urethane (PAU) core-shell copolymer dispersions by solvent free process

A method of producing dispersions from acrylate monomers by a solvent free process comprising:

• (a) synthesizing a solvent free polyurethane dispersion (PUD) in the amount of 40.0 wt % of the acrylate monomers as a seed emulsion;
• (b) taking an initiator in the amount of 0.20 wt. %-0.60 wt. % of the acrylate monomers to dissolve in deionized water to obtain an initiator solution which is equally distributed into first, second and third parts;
• (c) taking an emulsifier in the amount of 0.20 wt %-0.30 wt % of the acrylate monomers, polyoxyethylene alkyl ether ammonium sulfate in the amount of 0.20-0.30 wt. % of the acrylate monomer, and n-butyl acrylate (n-BA) as a soft monomer in the amount of 3.0-8.0 wt. % of the acrylate monomers to emulsify in the deionized water to obtain a first pre-emulsion acrylate;
• (d) taking the emulsifier in the amount of 0.20 wt %-0.30 wt % of the acrylate monomers, the polyoxyethylene alkyl ether ammonium sulfate in the amount of 0.13 wt %-0.30 wt % of the acrylate monomers, the n-BA in the amount of 43.3 wt %-86.7 wt % of the acrylate monomers, and methyl methacrylate (MMA) as a hard monomer in the amount of 8.0 wt %-52.0 wt % of the acrylate monomers to emulsify in the deionized water to obtain a second pre-emulsion acrylate;
• (e) pouring the solvent free PUD into a reaction vessel having a reaction temperature set at 70-90° C. and a rotational speed set at 300-500 rpm for reaction;
• (f) adding the first pre-emulsion acrylate and the first part of the initiator solution to the reaction vessel for one to two hours;
• (g) adding the second pre-emulsion acrylate and the second part of the initiator solution into the reaction vessel;
• (h) after adding more than half of the second pre-emulsion acrylate, adding the third part of the initiator solution into the reaction vessel;
• (i) increasing the reaction temperature up to 90-95° C.;
• (j) maintaining the reaction temperature for one to two hours and turning off heating;
• and
• (k) cooling the reaction vessel for one hour to produce a solid content of 40.0 wt % of solvent free super soft polyacrylate-urethane (PAU) core-shell copolymer dispersions, wherein a weight percentage ratio of polyacrylate (PA) and polyurethane (PU) is 25 wt %:100 wt % -100 wt %:100 wt %.