US 12,252,570 B2
Core-shell flow improver
Wayne R. Dreher, Germantown, TN (US); Kenneth W. Smith, Tonkawa, OK (US); Stuart N. Milligan, Ponca City, OK (US); Timothy L. Burden, Ponca City, OK (US); William F. Harris, Palm Harbor, FL (US); Ray L. Johnston, Ponca City, OK (US); Wolfgang Klesse, Aschaffenburg (DE); Gerold Schmitt, Aschaffenburg (DE); and John Wey, East Brunswick, NJ (US)
Assigned to LiquidPower Specialty Products Inc., Houston, TX (US)
Filed by Liquidpower Specialty Products Inc., Houston, TX (US)
Filed on May 13, 2021, as Appl. No. 17/319,669.
Application 17/319,669 is a division of application No. 15/210,918, filed on Jul. 15, 2016, granted, now 11,028,210.
Application 15/210,918 is a continuation of application No. 12/031,290, filed on Feb. 14, 2008, abandoned.
Prior Publication US 2021/0261707 A1, Aug. 26, 2021
Int. Cl. C08F 265/06 (2006.01); C08F 2/00 (2006.01); C08F 2/22 (2006.01); C08F 265/04 (2006.01); C08L 51/00 (2006.01); F17D 1/17 (2006.01)
CPC C08F 265/06 (2013.01) [C08F 2/002 (2013.01); C08F 2/22 (2013.01); C08F 265/04 (2013.01); C08L 51/003 (2013.01); F17D 1/17 (2013.01)] 17 Claims
 
1. A process for making a flow improver comprising:
(a) forming a plurality of core particles of a drag reducing polymer by emulsion polymerization, the drag reducing polymer having a weight average molecular weight (Mw) of at least about 5×106 g/mol; and
(b) forming a shell around each of the plurality of core particles by emulsion polymerization to thereby produce a plurality of core-shell particles,
wherein the forming of (b) comprises polymerizing one or more shell-forming monomers and at least one polymerizable surfactant so the shell comprises repeat units of the one or more shell-forming monomers and repeat units of the at least one polymerizable surfactant,
wherein a weight ratio of repeat units of the one or more shell-forming monomers and repeat units of the at least one polymerizable surfactant in the shell is in a range of from about 0.5:1 to about 40:1.