	US 11,999,808 B2
	Polymer particles with a gradient composition and methods of production thereof
Darryl W. Brousmiche, Grafton, MA (US); Kevin Daniel Wyndham, Upton, MA (US); Mingcheng Xu, Lexington, MA (US); and Michael F. Morris, Glossop (GB)
Assigned to Waters Technologies Corporation, Milford, MA (US)
Filed by Waters Technologies Corporation, Milford, MA (US)
Filed on Feb. 27, 2019, as Appl. No. 16/287,364.
Claims priority of provisional application 62/635,699, filed on Feb. 27, 2018.
Prior Publication US 2019/0322783 A1, Oct. 24, 2019
Int. Cl. C08F 285/00 (2006.01); C08F 2/04 (2006.01); C08F 2/06 (2006.01); C08F 212/08 (2006.01); C08F 220/56 (2006.01); C08K 5/00 (2006.01); C08K 5/14 (2006.01); C08K 5/23 (2006.01); C08L 39/06 (2006.01); C08F 220/28 (2006.01)

CPC C08F 2/04 (2013.01) [C08F 2/06 (2013.01); C08F 212/08 (2013.01); C08F 220/56 (2013.01); C08K 5/005 (2013.01); C08K 5/14 (2013.01); C08K 5/23 (2013.01); C08L 39/06 (2013.01); C08F 220/281 (2020.02); C08L 2205/24 (2013.01); C08L 2207/53 (2013.01)]

19 Claims

1. A method of producing monodisperse polymer particles comprising

a nucleation step by polymerizing mono-vinyl monomers together with a crosslinking monomer included in an amount of 3 weight percent based on total amount of mono-vinyl monomers to form a low crosslinked nucleus, wherein the crosslinking monomer comprises two or more vinyl groups, and wherein the nucleus contains live reactive sites for further polymerization;

a growth step by growing particles from the live reactive sites of the nucleation step by adding a monomer mixture or a sequence of monomer mixtures and varying the sequence, timing, and rate of the monomer mixture additions such that there are no boundaries throughout the grown polymer layers to form a gradient or multiple gradients as a predetermined pattern, wherein the gradient or multiple gradients are chemical and/or physical gradient(s).