Process for making silicone particles
AssigneeRohm and Haas Company
InventorsNewman M. Bortnick, Long-Jin Lin
Life of this patent
Estimating the term…
Abstract
An improved process for manufacturing silicone-containing polymer particles is provided. The process is particularly useful for preparing uniform, crosslinked silicone rubber particles of controlled particle size distribution and submicron size. In another embodiment, the process can be used to modify the surface properties of silicone-containing polymers to improve their compatibility with and dispersion into other polymers.
Claims20
A process for preparing spherical crosslinked silicone-containing polymer particles comprising:
- (a) forming an organosiloxane by hydrosilylation an organohydrosiloxane, containing at least two reactive silicon-hydrogen bonds per molecule, with a multifunctional unsaturated monomer in the presence of an effective amount of a hydrosilylation catalyst at a temperature of from about 25 C. to about 60 C., said multifunctional unsaturated monomer being unsaturated and reactive with said silicon-hydrogen bonds on said organohydrosiloxane while maintaining the ability after said reaction to be subsequently copolymerized in water and
- (b) polymerizing the organosiloxane with itself or with at least one other unsaturated monomer at a temperature from about 65 C. to about 95 C. to form said spherical crosslinked silicon-containing polymer particles.
A process for preparing predominantly submicron size spherical, crosslinked silicone-containing polymer particles comprising:
- (a) forming an organosiloxane by hydrosilylating an organohydrosiloxane, containing at least two reactive silicon-hydrogen bonds per molecule, with a multifunctional unsaturated monomer in the presence of an effective amount of a hydrosilylation catalyst at a temperature of from about 25 C., said multifunctional unsaturated monomer being unsaturated and reactive with said silicon-hydrogen bonds on said organohydrosiloxane while maintaining the ability after said reaction to be subsequently copolymerized using a free radical initiator, and
- (b) suspension polymerizing the organosiloxane with itself or another free radical initiatable unsaturated monomer in an aqueous emulsion containing at least one cosolvent other than water at a concentration of from about 1 to about 99 weight percent on total organics, said cosolvent having a non-polar solubility parameter in the range of from about 6.3 to about 7.4, a polar solubility parameter in the range of from about 3.1 to about 5.0, a hydrogen bonding solubility parameter in the range of from about 1.9 to about 4.6, and a total solubility parameter in the range of from about 7.8 to about 9.4.
A process for preparing a non-crosslinked silicone-containing polymer comprising:
- (a) forming a functionalized organosiloxane by hydrosilylating a monohydrosiloxane with a multifunctional unsaturated monomer in the presence of an effective amount of a hydrosilylation catalyst, said multifunctional unsaturated monomer being unsaturated and reactive with said silicon-hydrogen bonds on said organohydrosiloxane while maintaining the ability after said reaction to be subsequently copolymerized, and
- (b) copolymerizing said functionalized organosiloxane with at least one alpha, beta-ethylenically unsaturated monomer to form the non-crosslinked silicone-containing polymer.
Dependencies are inferred from the claim text.