Method for producing hybrid particles
The invention relates to a method for producing hybrid-particles containing polymer and SiO 2 -particles, wherein a) in a first polymerization step in aqueous medium a water-insoluble phase containing one or more monomeric and colloidal SiO 2 -particles having an average particle diameter of 1 to 150 nm are polymerized, and b) in a second polymerization step in aqueous medium one or more monomers are polymerized in the presence of the polymer obtained in the first polymerization step.
1. A method for producing a hybrid particle comprising polymer and SiO 2 particles, wherein
a) a water-insoluble phase comprising one or more monomers and colloidal SiO 2 particles with an average particle size from 1 to 150 nm is polymerized in a first polymerization stage in an aqueous medium, and
b) in a second polymerization stage in an aqueous medium, one or more monomers is/are polymerized in the presence of the polymer obtained in the first polymerization stage, said polymerization stage a) is carried out as batch polymerization and polymerization stage b) is carried out as feed polymerization, wherein polymerization stages a) and b) result in polymers differing from one another in composition.
2. The method according to claim 1 , in which two or more monomers each are used in polymerization stage a) and in polymerization stage b).
3. The method Method according claim 1 , in which a monomer-soluble initiator is used in polymerization stage a).
4. The method according to claim 3 , in which the polymer is chemically crosslinked in the first polymerization stage.
5. The method according to claim 4 , in which, in polymerization stage b), an aqueous emulsion of the monomers is added to the polymer obtained in polymerization stage a).
6. The method according to claim 5 , in which a water-soluble initiator is used in polymerization stage b).
7. The method according to claim 6 , in which the average size of the water-soluble phase is in the range from 100 to 5000 nm, preferably from 150 to 2000 nm, particularly preferably between 200 and 1500 nm.
8. The method according to claim 7 , in which monomers used comprise vinyl monomers.
9. The method according to claim 8 , in which two or more acrylate monomers and/or methacrylate monomers are used in polymerization stage a) and in polymerization stage b).
10. The method according to claim 9 , in which monomers used in polymerization stage a) and in polymerization stage b) comprise i) methyl methacrylate and ii) methyl acrylate, ethyl acrylate, butyl acrylate, and/or ethyihexyl acrylate.
11. The method according to claim 10 , in which the methyl methacrylate monomer content of the polymer obtained in polymerization stage a) is lower than that of the polymer obtained in polymerization stage b).
12. The method according to claim 11 , in which the SiO 2 particles have been surface-modified via unreactive and/or reactive groups.
13. The method according to claim 1 in which the average size of the SiO 2 particles is from 2 to 100 nm, preferably from 3 to 75 nm, more preferably from 4 to 50 nm, more preferably from 5 to 30 nm.
14. An aqueous polymer dispersion obtained by the method according to claim 13 .
15. A method for producing a polymeric material, wherein the water is removed from an aqueous dispersion according to claim 14 .
16. The method according to claim 7 , wherein the vinyl monomers are selected from the group of the vinyl halides, vinyl esters, styrene and substituted styrenes, acrylic and methacrylic acid, and derivatives thereof.
17. The method according to claim 7 , wherein the vinyl monomers are selected from the group of the vinyl esters, styrene and substituted styrenes, and acrylic and methacrylic acids, and esters thereof.