US 11,667,739 B2
Making particles with radial variation
Andrew M. Savo, Cherry Hill, NJ (US); John David Finch, North Wales, PA (US); and Thomas Jones, Jenkintown, PA (US)
Assigned to DDP SPECIALTY ELECTRONIC MATERIALS US 8, LLC, Wilmington, DE (US)
Appl. No. 16/648,055
Filed by DDP SPECIALTY ELECTRONIC MATERIALS US 8, LLC, Collegeville, PA (US)
PCT Filed Sep. 21, 2018, PCT No. PCT/US2018/052162
§ 371(c)(1), (2) Date Mar. 17, 2020,
PCT Pub. No. WO2019/067318, PCT Pub. Date Apr. 4, 2019.
Claims priority of provisional application 62/565,405, filed on Sep. 29, 2017.
Prior Publication US 2020/0277410 A1, Sep. 3, 2020
Int. Cl. C08F 212/08 (2006.01); C08F 8/36 (2006.01); B01J 39/20 (2006.01); C08F 2/18 (2006.01)
CPC C08F 212/08 (2013.01) [B01J 39/20 (2013.01); C08F 2/18 (2013.01); C08F 8/36 (2013.01); C08F 2800/20 (2013.01); C08L 2207/53 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A process of making a polymeric bead comprising (a) providing a suspension of monomer droplets in an aqueous medium at pH of 7 or less, wherein the monomer droplets comprise one or more monofunctional vinyl monomers, one or more multifunctional vinyl monomers, and one or more initiators, wherein the aqueous medium comprises one or more derivatives of a nitrite salt in an amount, by weight based on the weight of the aqueous medium, of 0.005% to 0.5%, and (b) initiating polymerization of the monomer, wherein no pH-raising substance is added after beginning step (b) until 60% or more by weight of all monofunctional monomer has been converted to polymer; wherein the polymeric bead has a radius R; wherein the polymeric bead comprises 0.3% to 20% by weight, based on the weight of the polymeric bead, of polymerized units of the one or more multifunctional vinyl monomers and 80% to 99.7% by weight, based on the weight of the polymeric bead, of polymerized units of the one or more monofunctional vinyl monomers; wherein one or more of the monofunctional vinyl monomers or one or more of the multifunctional vinyl monomers comprises an aryl group; and
(i) wherein the polymerized units of multifunctional vinyl monomer have radial distribution factor MR of 0.9 to 1.1, wherein MR=CMSHELL/CMCORE, wherein CMSHELL is the average concentration of polymerized units of multifunctional vinyl monomer located at a distance from the center of the bead of 0.8*R to R, and wherein CMCORE is the average concentration of polymerized units of multifunctional vinyl monomer located at a distance from the center of the bead of 0 to 0.5*R, and
(ii) wherein some of the vinyl groups in the polymerized units of multifunctional vinyl monomer are unreacted, and the unreacted vinyl groups have a radial distribution factor VR of 2.5 or higher, wherein VR is determined by a Raman spectroscopic measurement performed on the bead, wherein VR=V1SHELL/V1CORE, wherein V1SHELL is the average of ratio V1 for measurements made at a distance from the center of the bead of 0.8*R to R, wherein V1CORE is the average of ratio V1 for measurements made at a distance from the center of the bead of 0 to 0.5*R, wherein V1=PCC/PAR, wherein PCC is the height of the Raman spectroscopic peak due to stretching of carbon-carbon double bonds, and PAR is the height of the Raman spectroscopic reference peak due to stretching of the aryl group at 1000 cm−1.