IP Library › Granted Patent US 7,540,962
Granted Patent B2
US 7,540,962 · App. 11/809,096 · Granted Jun 2, 2009

Method of preparing spheroid polymer particles having a narrow size distribution by dispersion polymerization, particles obtainable by the method and use of these particles

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Quick Facts
Patent No.
US 7,540,962
App. No.
11/809,096
Granted
Jun 2, 2009
Kind
B2
Abstract

The invention relates to a method of preparing spheroid polymer particles having a narrow size distribution by dispersion polymerization. This method comprises the steps of: providing a two-phase system in the form of a dispersion comprising an organic phase of droplets dispersed in an aqueous medium, mixing said organic phase in said aqueous medium under agitation without using a dispersion stabilizing agent to stabilize the dispersion, wherein the organic phase comprises at least a crosslinkable monomer, a polymerization initiator and an organic solvent for said monomer, and allowing the crosslinkable monomers to polymerize, while the two-phase system is agitated.

Claims (10)

1. Method of preparing spheroid polymer particles having a narrow particle size distribution by dispersion according to the ratio F≦2, wherein F=dp(%<90)/ dp(%<10), wherein dp is the particle diameter in microns and wherein dp(%<90) and dp(%<10), respectively, designate the top-limit for a group of particles and the bottom-limit for a group of particles, with dp(%<90) being a value of a particle size below which 90% of the particles are smaller in size, and, dp(%<10) being a value of a particle size below which 10% of the particles are smaller, such particles made by dispersion polymerization which comprises the steps of:

providing a two-phase system in the form of a dispersion comprising an organic phase of droplets dispersed in an aqueous medium containing a dissolved salt by mixing said organic phase in said aqueous medium under agitation and forming said droplets with less than 0.1 wt. % or without using a dispersion stabilizing agent to stabilize the dispersion, wherein the organic phase comprises at least a crosslinkable monomer, a polymerization initiator and an organic solvent for said monomer; and

allowing the crosslinkable monomer to polymerize, while the two-phase system is agitated without adding of additional organic phase during said polymerization.

2. Method according to claim 1 , wherein the organic phase comprises at least two monomers, of which one is a crosslinkable monomer and one is a non-crosslinkable monomer.

3. Method according to claim 1 or 2 , wherein the crosslinkable monomer is a hydrocarbon comprising two or more vinyl groups.

4. Method according to claim 2 , wherein the non-crosslinkable monomer is a hydrocarbon comprising one vinyl group.

5. Method according to claim 1 or 2 or 4 , wherein the crosslinkable monomer is reacted in the presence of a free radical initiator.

6. Method according to claim 1 or 2 or 4 , wherein the aqueous medium comprises a dissolved salt.

7. Method according to claim 1 or 2 or 4 , wherein said organic solvent for a monomer is chosen from the group consisting of water-insoluble aliphatic hydrocarbons, aliphatic hydrocarbons with a hydroxyl group or a combination thereof.

8. Method according to claim 1 or 2 or 4 , wherein the polymer particle is chemically modified into an IEX material.