Process for macroporous acrylic resins

1. A method for producing a macroporous acrylic resin, said method comprising steps of:

(a) combining: (i) water; (ii) a C 1 -C 4 alkyl acrylate; (iii) a crosslinker; (iv) an organic solvent; and (v) a polymerization initiator; to form a reaction mixture;

(b) forming a stable dispersion of organic droplets, and allowing said droplets to react to form a resin;

(c) adding an acid or a base without removing more than 50% of said organic solvent; and

(d) heating to hydrolyze ester groups on the resin.

2. The method of claim 1 in which said acid or base is an inorganic hydroxide, and the organic solvent is selected from among C 7 -C 10 hydrocarbons, C 3 -C 10 halogenated hydrocarbons, C 4 -C 10 ketones, C 4 -C 10 alcohols, C 4 -C 10 alkyl esters, C 4 -C 10 aryl esters, C 4 -C 10 mixed alkyl/aryl esters, and combinations thereof.

3. The method of claim 2 in which said crosslinker is present in an amount of at least 5%, based on total amount of C 1 -C 4 alkyl acrylate and crosslinker.

4. The method of claim 3 in which said C 1 -C 4 alkyl acrylate is methyl acrylate.

5. The method of claim 4 in which said organic solvent is present in an amount from 30% to 80%, based on total amount of methyl acrylate, crosslinker and organic solvent.

6. A method for producing a macroporous acrylic resin; said method comprising steps of:

(a) combining: (i) water; (ii) at least one monoethylenically unsaturated monomer selected from C 1 -C 4 alkyl acrylates, acrylonitrile and methacrylic acid; (iii) a crosslinker; and (iv) a polymerization initiator; to form a reaction mixture;

(b) forming a stable dispersion of organic droplets, and allowing said droplets to react to form a resin;

(c) adding an acid or a base without removing more than 50% of said aqueous solution; and

(d) heating to hydrolyze ester or nitrile groups on the resin.

7. The method of claim 6 in which said at least one monoethylenically unsaturated monomer is at least one C 1 -C 4 alkyl acrylate, and further comprising an organic solvent in the reaction mixture.

8. The method of claim 7 further comprising distilling at least 50% of the organic solvent during hydrolysis of ester groups on the resin, without removing more than 50% of said aqueous solution; and in which said acid or base is an inorganic hydroxide, and the organic solvent is selected from among C 7 -C 10 hydrocarbons, C 3 -C 10 halogenated hydrocarbons, C 4 -C 10 ketones, C 4 -C 10 alcohols, C 4 -C 10 alkyl esters, C 4 -C 10 aryl esters, C 4 -C 10 mixed alkyl/aryl esters, and combinations thereof.

9. The method of claim 8 in which said crosslinker is present in an amount of at least 5%, based on total amount of said at least one monoethylenically unsaturated monomer and crosslinker.

10. The method of claim 9 in which said at least one monoethylenically unsaturated monomer is methyl acrylate.

11. A method for producing a macroporous core-shell acrylic resin bead; said method comprising steps of

(a) combining: (i) water; (ii) a C 1 -C 4 alkyl acrylate; (iii) a crosslinker; (iv) a hydrophobic organic solvent; and (v) a polymerization initiator;

(b) forming a stable dispersion of organic droplets, and allowing said droplets to react to form a resin;

(c) adding an acid or a base without removing more than 50% of said aqueous solution; and

(d) heating to hydrolyze ester groups on the resin.

12. The method of claim 11 further comprising distilling at least 50% of the organic solvent without removing more than 50% of said aqueous solution.

13. The method of claim 12 in which solvent is distilled during hydrolysis of ester groups on the resin, and the hydrophobic solvent is selected from among C 7 -C 10 hydrocarbons, C 3 -C 10 halogenated hydrocarbons, C 4 -C 10 ketones, and combinations thereof.

14. The method of claim 13 in which said crosslinker is present in an amount of at least 5%, based on total amount of C 1 -C 4 alkyl acrylate and crosslinker.

15. The method of claim 14 in which said C 1 -C 4 alkyl acrylate is methyl acrylate.

16. The method of claim 15 in which said hydrophobic organic solvent is present in an amount from 30% to 80%, based on total amount of methyl acrylate, crosslinker and organic solvent.