Resin molding, method for manufacturing the same, and metal mold for manufacturing the same

Abstract

A resin molding is provided. A main body is comprised of 100 parts by weight of thermoplastic resin and 0.1 to 4 parts by weight of bright material having the aspect ratio of 30 to 50. A main body has a design surface formed with a groove. The lower limit of the depth of the groove is set to 0.3 mm and the upper limit of the depth of the groove is set to 0.5 mm.

1 . A resin molding, comprising:
 a main body which is comprised of 100 parts by weight of thermoplastic resin and 0.1 to 4 parts by weight of bright material having the aspect ratio of 30 to 50,   wherein a main body has a design surface formed with a groove; and   wherein the lower limit of the depth of the groove is set to 0.3 mm and the upper limit of the depth of the groove is set to 0.5 mm.   
   
   
       2 . The resin molding as set forth in  claim 1 , wherein Y and Xd [mm] satisfy the following expressions:
   Y≧30;     Xd≧0.3; and       Y≦− 100 Xd+ 80,   where Y denotes the aspect ratio of the bright material and Xd denotes the depth of the groove.   
   
   
       3 . The resin molding as set forth in  claim 1 , wherein Y and Xd further satisfy the following expression:
     Y≦− 50 Xd+ 55.   
   
   
       4 . The resin molding as set forth in  claim 1 , wherein the bright material has the mean particle diameter of 5 to 20 μm. 
   
   
       5 . The resin molding as set forth in  claim 1 , wherein the groove is formed into a rectangular shape on the design surface. 
   
   
       6 . A method for manufacturing a resin molding, comprising:
 laminating a plurality of plates to form a cavity and a gate through which resin material is injected into the cavity;   injecting the resin material which is comprised of 100 parts by weight of thermoplastic resin and 0.1 to 4 parts by weight of bright material, into the cavity through the gate;   hardening the resin material to form the resin molding; and   separating the plates to extract the resin molding from the cavity,   wherein the plates are formed such that the resin molding includes a main body having a round-shaped design surface formed with a plurality of rectangular-shaped grooves, the longest groove of which extends in a first direction; and   wherein the plates are formed such that the gate extends toward a center of the round-shaped design surface and at an angle range of 45°±30° with respect to the first direction.   
   
   
       7 . The method as set forth in  claim 6 , wherein the plates are formed such that the gate extends at an angle range of 45°±10° with respect to the first direction. 
   
   
       8 . The method as set forth in  claim 7 , wherein the plates are formed such that the gate extends at an angle of 45° with respect to the first direction. 
   
   
       9 . The method as set forth in  claim 6 ,
 wherein the bright material has the aspect ratio of 30 to 50,   wherein the plates are formed such that the lower limit of the depth of the grooves is set to 0.3 mm and the upper limit of the depth of the grooves is set to 0.5 mm.   
   
   
       10 . The method as set forth in  claim 9 , wherein the plates are formed such that Y and Xd [mm] satisfy the following expressions:
   Y≧30;     Xd≧0.3; and       Y≦− 100 Xd+ 80,   where Y denotes the aspect ratio of the bright material and Xd denotes the depth of the groove.   
   
   
       11 . The method as set forth in  claim 10 , wherein the plates are formed such that Y and Xd further satisfy the following expression:
     Y≦− 50 Xd+ 55.   
   
   
       12 . The method as set forth in  claim 6 , wherein the bright material has the mean particle diameter of 5 to 20 μm. 
   
   
       13 . A metal mold for manufacturing a resin molding, comprising:
 a first plate formed with a sprue; and   a second plate;   wherein the first plate and the second plate are formed such that a cavity, a gate and a runner are formed when the first plate is laminated on the second plate so that resin material is injected from the sprue into the cavity through the runner and the gate to form the resin molding;   wherein the first plate and the second plate are formed such that the resin molding includes a main body having a round-shaped design surface formed with a plurality of rectangular-shaped grooves, the longest groove of which extends in a first direction; and   wherein the first plate and the second plate are formed such that the gate extends toward a center of the round-shaped design surface and at an angle range of 45°±30° with respect to the first direction.   
   
   
       14 . The metal mold as set forth in  claim 13 , wherein the first plate and the second plate are formed such that the gate extends at an angle range of 45°±10° with respect to the first direction. 
   
   
       15 . The metal mold as set forth in  claim 14 , wherein the first plate and the second plate are formed such that the gate extends at an angle of 45° with respect to the first direction. 
   
   
       16 . The metal mold as set forth in  claim 13 , wherein the first plate and the second plate are formed such that the lower limit of the depth of the grooves is set to 0.3 mm and the upper limit of the depth of the grooves is set to 0.5 mm.