Process for the preparation of monodisperse polymer particles

Abstract

A process for the preparation of monodisperse polymer particles which are formed by contacting monomers with aqueous dispersions comprising monodisperse swellable seed polymers/oligomers, and initiating polymerization in the presence of a steric stabilizer. The resulting swollen seed particles are characterized by the particle mode diameter.

1 . A process for the preparation of monodisperse polymer particles having diameters of 1 μm to 6 μm, the process comprising:
 forming an aqueous dispersion comprising monodisperse swellable seed particles and an anionic surfactant;   contacting the aqueous dispersion with a monomer selected from the group consisting of acrylic monomers, methacrylate monomers and vinyl monomers selected from the group consisting of styrene, divinylbenzene (DVB), ethyl vinyl benzene, vinyl pyridine, amino-styrene, methyl-styrene, dimethylstyrene, ethyl styrene, ethyl-methyl-styrene, p-chlorostyrene and 2,4-dichlorostyrene;   allowing the monomer to diffuse into the seed particles to form an aqueous dispersion of swollen seed particles; and   initiating polymerization of the monomer in the aqueous dispersion of swollen seed particles;   wherein the aqueous dispersion of swollen seed particles further comprises a polyvinylpyrrolidone.   
     
     
         2 . The process of  claim 1 , wherein the polyvinylpyrrolidone has an average molecular weight of 10 kD to 2000 kD. 
     
     
         3 . The process of  claim 1 , wherein the monodisperse swellable seed particles are monodisperse swellable seed oligomer particles. 
     
     
         4 . The process of  claim 1 , wherein the monomer comprises at least 30% by weight divinyl benzene. 
     
     
         5 . The process of  claim 1 , wherein the anionic surfactant is sodium dodecyl sulfate. 
     
     
         6 . A process for the preparation of monodisperse polymer particles, the process comprising:
 forming an aqueous dispersion comprising monodisperse swellable seed particles and an anionic surfactant;   contacting the aqueous dispersion of seed particles with a monomer;   allowing the monomer to diffuse into the seed particles to form an aqueous dispersion of swollen seed particles having a mode diameter of 5 μm to 200 μm; and   initiating polymerization of the monomer in the aqueous dispersion of swollen seed particles;   wherein the aqueous dispersion of swollen seed particles further comprises a water soluble cellulose ether of weight average molecular weight 10 kD to 100 kD.   
     
     
         7 . The process of  claim 6 , wherein the water soluble cellulose ether is a hydroxy propylmethyl cellulose. 
     
     
         8 . The process of  claim 6 , wherein the monomer comprises at least 30% by weight divinyl benzene. 
     
     
         9 . The process of  claim 6 , wherein the anionic surfactant is sodium dodecyl sulfate. 
     
     
         10 . A process for the preparation of monodisperse polymer particles having a diameter of at least 16 μm, the process comprising:
 forming an aqueous dispersion comprising monodisperse swellable seed particles and an anionic surfactant;   contacting the aqueous dispersion of seed particles with a monomer;   allowing the monomer to diffuse into the seed particles to form an aqueous dispersion of swollen seed particles; and   initiating polymerization of the monomer in the aqueous dispersion of swollen seed particles to produce a polymer;   wherein the swollen seed particles contain at least two porogens, at least one of which is a solvent for the polymer produced and at least one of which is not a solvent for the polymer produced, and at least one porogen is an aliphatic hydrocarbon having up to 12 carbon atoms.   
     
     
         11 . The process of  claim 10 , wherein the porogens comprise toluene and n-heptane. 
     
     
         12 . The process of  claim 10 , wherein the aqueous dispersion of swollen seed particles further comprises a water soluble cellulose ether or a polyvinylpyrrolidone. 
     
     
         13 . The process of  claim 10 , wherein the aqueous dispersion comprises droplets comprising an organic compound with a molecular weight below 5000 Dalton and a water solubility at 25° C. of less than 10 −2  g/L. 
     
     
         14 . The process of  claim 10 , wherein the aqueous dispersion comprises an organic solvent. 
     
     
         15 . The process of  claim 10 , wherein the aqueous dispersion comprises dioctanoyl peroxide. 
     
     
         16 . The process of  claim 10 , wherein the monomer comprises at least 30% by weight divinyl benzene. 
     
     
         17 . The process of  claim 10 , wherein the anionic surfactant is sodium dodecyl sulfate. 
     
     
         18 . A process for the preparation of monodisperse polymer particles, the process comprising:
 forming an aqueous dispersion comprising monodisperse swellable seed particles and an anionic surfactant;   contacting the aqueous dispersion of seed particles with at least two monomers;   allowing the monomers to diffuse into the seed particles to form an aqueous dispersion of swollen seed particles that swell as least 3.5 times in diameter; and   initiating polymerization of the monomers in the aqueous dispersion of swollen seed particles to produce polymer particles;   wherein at least two monomers are selected from the group consisting of acrylic, methacrylic acid and ester monomers and combinations of these monomers; and   wherein the aqueous phase of the aqueous dispersion of swollen seed particles during polymerization further contains a steric stabilizer.   
     
     
         19 . The process of  claim 18 , wherein at least one of the monomers is glycidyl methacrylate. 
     
     
         20 . The process of  claim 18 , wherein the aqueous dispersion comprises droplets comprising an organic compound with a molecular weight below 5000 Dalton and a water solubility at 25° C. of less than 10 −2  g/L and optionally an organic solvent. 
     
     
         21 . The process of  claim 18 , wherein the anionic surfactant is sodium dodecyl sulfate. 
     
     
         22 . The process of  claim 18 , wherein the monodisperse swellable seed particles are monodisperse swellable seed oligomer particles.