| 摘要 |
1416605 Pellets for moulding GENERAL ELECTRIC CO 5 Nov 1973 [6 Nov 1972] 51255/73 Heading B5A [Also in Division C3] A pelletized, heat fusible, thermosettable, injection mouldable composition comprising a thermosettable phenol-aldehyde resin and a filler is prepared by feeding the composition to a screw extruder, advancing the composition through the extruder at a temperature of less than 290‹ F. for a sufficient time to render the resin molten, extruding the composition through a die orifice and comminuting the extrudate into pellets of at least <SP>1</SP>/ 16 inch in diameter and mixing the pellets with a minor amount of a metallic salt of a C 8 -C 20 fatty acid. The extrudate may be rapidly cooled as it is comminuted into pellets. The feed material may be premixed or the ingredients may be fed separately to the extruder either at room temperature or at an elevated temperature. The pellets generally have a bulk factor of less than 2À3. The metal salt may form a coating on the pellets. Suitable metal salts are the Li, Na, K, Mg, Ca, Ba, Zn, Cd and Al salts of palmitic, stearic, lauric, oleic, sebacic, ricinoleic and palmi. toleic acids. Suitable fillers include asbestos fibres, wood flour, cotton flock, cellulose flock, wool flock, aluminium silicate, calcium carbonate, talcs and glass fibres. Other additives such as lime and stearic acid may also be used. In Example I pellets <SP>1</SP>/ 8 inch diameter and <SP>1</SP>/ 8 inch long prepared as above from a powdered phenol-formaldehyde novolac resin, hexamethylenetetramine as crosslinking agent, asbestos fibres and wood flour are blended with zinc stearate and subsequently injection moulded. |
