METHOD AND A DEVICE FOR PREPARATION OF EXPANDED MICROSPHERES

• Main Authors: AJDÉN, Per, SVEDBERG, Lars-Olof
• Format: Patent
• Language: English; French; German
• Published: 19.04.2017
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; ARTIFICIAL STONE; CEMENTS; CERAMICS; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; CONCRETE; GENERAL PROCESSES OF COMPOUNDING; LIME, MAGNESIA; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; REFRACTORIES; SLAG; THEIR PREPARATION OR CHEMICAL WORKING-UP; THEIR RELEVANT APPARATUS; TRANSPORTING; TREATMENT OF NATURAL STONE; WORKING-UP

The invention relates to a method and a device for the preparation of expanded thermoplastic microspheres from unexpanded thermally expandable thermoplastic microspheres comprising a thermoplastic polymer shell encapsulating a blowing agent. The method comprises: (a) feeding a slurry of such expandable thermoplastic microspheres in a liquid medium into a heating zone; (b) heating the slurry in the heating zone, without direct contact with any fluid heat transfer medium, so the expandable microspheres reach at least a temperature at which they would have started to expand at atmospheric pressure, and maintaining a pressure in the heating zone sufficiently high so the microspheres in the slurry do not-fully expand; and, (c) withdrawing the slurry of expandable microspheres from the heating zone into a zone with a pressure sufficiently low for the microspheres to expand.