Thermoplastic resins have been used in various extensive applications such as electric, electronic and OA equipments, vehicles, building materials, agricultural materials and sundries because the resins are excellent in various properties such as mechanical properties, electric properties, light weight and moldability. In addition, as the method for improving a rigidity, a strength, dimensional characteristics, etc., of the thermoplastic resins, a method of incorporating inorganic fillers thereinto has been generally and extensively used. In the applications requiring a good appearance, there have been proposed many methods for incorporating small size inorganic fillers such as talc into the resins. Also, in recent years, in the application fields of interior parts, exterior parts and outer plate parts of vehicles as well as various housing members which need to exhibit a good appearance, it has been required that these molded articles have an increased size and a high rigidity. Therefore, as to the impact resistance required for these molded articles, impact characteristics such as a surface impact strength becomes more important rather than Izod impact strength owing to the relation with a strain rate thereof. As a result, it is required to provide a material capable of further improving these impact characteristics by incorporating small size inorganic fillers thereinto.
However, when incorporating the small size inorganic fillers into the thermoplastic resins, there tend to arise problems such as clogging of a hopper, deteriorated extrusion moldability such as poor intrusion into an extruder, and low impact resistance of the resultant resin composition owing to poor dispersion of the inorganic fillers therein. In addition, when incorporating the inorganic fillers into engineering plastics having a high extruding or molding temperature, there tend to arise problems such as deterioration in thermal stability and hue. In particular, in the case where silicate compounds such as talc are incorporated into thermoplastic resin compositions comprising an aromatic polycarbonate resin, adverse influences by decomposition of the resin tend to be remarkably caused, resulting in problems such as deterioration in impact resistance, thermal stability, hue, etc.
Thus, in the application fields of thermoplastic resin compositions into which small size inorganic fillers are incorporated, it has been strongly demanded to develop materials which are excellent in various properties such as extrusion moldability, rigidity, impact resistance, thermal stability and hue. To solve the above conventional problems, there have been proposed, for example, the techniques using, as the small size filler, a talc that is increased in bulk specific gravity by mechanical compression (for example, refer to Patent Documents 1 and 2), and the technique using a talc having a specific electric conductivity (for example, refer to Patent Document 3). In addition, in the Patent Document 3, it is described that the talc is preferably in the form of a compressed and granulated product, and the talc may be granulated using a binder. However, even when using the techniques specifically described in these Patent documents, the obtained thermoplastic resin compositions are still unsatisfactory in extrusion moldability, thermal stability and impact resistance.
On the other hand, there have been proposed the technique employing a granular inorganic filler that is granulated by using a binder (for example, refer to Patent Document 4), and a thermoplastic resin composition obtained by incorporating a granular talc granulated using a specific amount of bentonite, in engineering plastics such as aromatic polycarbonate resins (for example, refer to Patent Document 5). However, the thermoplastic resin compositions obtained by incorporating the granular talc granulated by using a binder into engineering plastics such as aromatic polycarbonate resins as described in these Patent Documents, are not necessarily satisfactory in impact resistance, thermal stability and hue.    Patent Document 1: Japanese Patent Application Laid-Open (KOKAI) No. 8-176339    Patent Document 2: Japanese Patent Application Laid-Open (KOKAI) No. 10-101914    Patent Document 3: Japanese Patent Application Laid-Open (KOKAI) No. 2002-60637    Patent Document 4: Japanese Patent Application Laid-Open (KOKAI) No. 2002-220549    Patent Document 5: Japanese Patent Application Laid-Open (KOKAI) No. 2006-77176
USPTO Backgrounds
USPTO Backgrounds