Liquid-crystalline polymer composition and molded article thereof

Abstract

A liquid-crystalline polymer composition containing a liquid-crystalline polymer and a magnetic filler formed by heat-treating a composite material of a ceramic powder and a soft magnetic metal powder in an inert gas atmosphere.

1 . A liquid-crystalline polymer composition comprising:
 a liquid-crystalline polymer; and   a magnetic filler formed by heat-treating a composite material of a ceramic powder and a soft magnetic metal powder in an inert gas atmosphere.   
     
     
         2 . The liquid-crystalline polymer composition according to  claim 1 , wherein the liquid-crystalline polymer is a fully aromatic liquid-crystalline polyester. 
     
     
         3 . The liquid-crystalline polymer composition according to  claim 1 , wherein the liquid-crystalline polymer has a repeating unit represented by formula (i), a repeating unit represented by formula (ii) and a repeating unit represented by formula (iii):
   —O—Ar 1 —CO—  (i)
     —CO—Ar 2 —CO—  (ii)
     —O—Ar 3 —O—  (iii)
   wherein Ar 1  represents a 1,4-phenylene group, a 2,6-naphthalenediyl group or a 4,4′-biphenylylene group; Ar 2  and Ar 3  each independently represent a 1,4-phenylene group, a 2,6-naphthalenediyl group, a 1,3-phenylene group or a 4,4′-biphenylylene group; and a hydrogen atom present in the group represented by Ar 1 , Ar 2 , or Ar 3  may each independently be replaced by a halogen atom, an alkyl group or an aryl group.   
     
     
         4 . The liquid-crystalline polymer composition according to  claim 1 , wherein the ceramic powder contains silicon oxide as a main component. 
     
     
         5 . The liquid-crystalline polymer composition according to  claim 1 , wherein the soft magnetic metal powder contains iron or an iron alloy as a main component. 
     
     
         6 . The liquid-crystalline polymer composition according to  claim 1 , wherein an aspect ratio of the soft magnetic metal powder is 2 or more. 
     
     
         7 . The liquid-crystalline polymer composition according to  claim 1 , wherein the composite material is a composite material formed by coating the soft magnetic metal powder with the ceramic powder. 
     
     
         8 . The liquid-crystalline polymer composition according to  claim 1 , wherein the magnetic filler is a magnetic filler formed by heat-treating the composite material in the inert gas atmosphere at 800° C. or higher. 
     
     
         9 . The liquid-crystalline polymer composition according to  claim 1 , wherein the composite material is a composite material formed by coating the soft magnetic metal powder with the ceramic powder, and wherein the magnetic filler is a magnetic filler formed by heat-treating the composite material in the inert gas atmosphere at 800° C. or higher. 
     
     
         10 . The liquid-crystalline polymer composition according to  claim 1 , wherein a content of the magnetic filler is 100 to 450 parts by mass with respect to 100 parts by mass of the liquid-crystalline polymer. 
     
     
         11 . The liquid-crystalline polymer composition according to  claim 1 , obtained by:
 supplying the liquid-crystalline polymer and the magnetic filler to a melt-kneading extruder equipped with a screw having a ratio (L/D) of an effective length (L) of the screw to a diameter (D) of the screw of 20 or more, a first supply port, and a second supply port provided in a downstream side of the first supply port in an extrusion direction, such that 50 mass % or more of the total supply amount of the liquid-crystalline polymer and 50 mass % or less of the total supply amount of the magnetic filler are supplied from the first supply port and a remaining portion of the liquid-crystalline polymer and a remaining portion of the magnetic filler are supplied from the second supply port; and   melt-kneading the supplied materials.   
     
     
         12 . A molded article formed by molding the liquid-crystalline polymer composition according to  claim 1 . 
     
     
         13 . The molded article according to  claim 12 , wherein a volume resistivity value is 10 6  Ωm or more, and an attenuation effect with respect to an electromagnetic wave at frequency 2.5 GHz is 1 dB or more.