Foaming agents for thermoplastic resins and method of preparing same

• Main Authors: TINSON ART, D'UVA SALVATORE, HU JIANZHONG, LEFAS JOHN
• Format: Patent
• Language: English
• Published: 29.01.2013
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM,RUBIDIUM, CAESIUM, OR FRANCIUM; INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OFSOLID INORGANIC COMPOUNDS; INORGANIC CHEMISTRY; METALLURGY; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

Ultra-fine sodium bicarbonate powder (mean particle size less than 5 microns) is produced by the mixing and reaction under agitation at control temperatures of solutions of ammonium bicarbonate and sodium chloride. Precipitated sodium bicarbonate is separated by filtration as a slurry which is dried to produce ultra-fine sodium bicarbonate. Ultra-fine sodium bicarbonate produced by this method also exhibits a narrow particle size distribution which is advantageous in blowing agents for thermoplastic resins, to produce a foamed resin with small cells of a narrow size distribution.