Water expandable polymer beads containing latex particles
US9850361B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 2015 |
| Grant date | Dec 26, 2017 |
| Priority date | — |
| Expiry date | Nov 30, 2035 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2471/12
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An emulsifier-free process for the preparation of water expandable polymer beads, including: a) providing an emulsifier-free starting composition comprising styrene, b) prepolymerizing the starting composition to obtain a prepolymer composition, c) mixing an aqueous blowing agent with the prepolymer composition at an elevated temperature to obtain an inverse emulsion of water droplets in the prepolymer composition, wherein the aqueous blowing agent comprises water and a water soluble initiator dissolved in the water and the water droplets comprise spheres of a styrene polymer, wherein the water soluble initiator partly decomposes due to the elevated temperature leading to the formation of the inverse emulsion of water droplets in the prepolymer composition, d) suspending the inverse emulsion in an aqueous medium to yield an aqueous suspension of suspended droplets and e) polymerizing monomers in the droplets of the suspension obtained by step d) to obtain the water expandable polymer beads.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.