Masterbatch, masterbatch group, production method for masterbatch, and synthetic resin molded article

Abstract

The present invention aims to provide a masterbatch containing a large amount of an aluminum component and having high pellet strength, wherein aluminum particles retain their inherent brightness and the amount of a component which may impair the strength or appearance of a synthetic resin molded article is small. The masterbatch of the present invention contains aluminum particles, a heat-resistant wetting agent, and a resin, wherein the proportion of the aluminum particles in the masterbatch is 50 to 80% by weight, the resin has a melt flow rate of 0.2 to 60 g/10 min, and the proportion of wax having a melt flow rate of more than 60 g/10 min and a melt viscosity at 140° C. of 15 to 8000 mPa·s in the masterbatch is 10% by weight or less.

The invention claimed is: 
     
       1. A masterbatch comprising:
 aluminum particles; 
 a heat-resistant wetting agent; and 
 a resin, 
 wherein a ratio of the aluminum particles in the masterbatch is in a range from 50 to 80% by weight, 
 the resin is a polymer alloy having a melt tension at 190° C. in a range from 20 to 100 mN, 
 the resin has a melt flow rate in a range from 0.2 to 60 g/10 min, 
 a ratio of wax having a melt flow rate in a range of more than 60 g/10 min and a melt viscosity at 140° C. in a range from 15 to 8000 mPa·s in the masterbatch is in a range of 10% by weight or less, and 
 the heat-resistant wetting agent is one or more polyethylene glycols. 
 
     
     
       2. The masterbatch according to  claim 1 ,
 wherein the aluminum particles are surface-coated aluminum particles. 
 
     
     
       3. The masterbatch according to  claim 1  further comprising a melt tension improver. 
     
     
       4. The masterbatch according to  claim 1 ,
 wherein the resin comprises a high melt tension resin having a melt tension at 190° C. in a range from 30 to 200 mN. 
 
     
     
       5. The masterbatch according to  claim 1  further comprising a metal deactivator. 
     
     
       6. A masterbatch group comprising a plurality of the masterbatches according to  claim 1 ,
 wherein each masterbatch has a pellet shape, 
 the plurality of the masterbatches included in the masterbatch group has a relative standard deviation of a major axis in a range of 5.00% or less, 
 the plurality of the masterbatches included in the masterbatch group has a relative standard deviation of a minor axis in a range of 5.00% or less, and 
 the plurality of the masterbatches included in the masterbatch group has a relative standard deviation of a length in a range of 5.00% or less. 
 
     
     
       7. The masterbatch group according to  claim 6 ,
 wherein an average major axis of the plurality of the masterbatches included in the masterbatch group is in a range from 2.0 to 4.0 mm, 
 an average minor axis of the plurality of the masterbatches included in the masterbatch group is in a range from 2.0 to 4.0 mm, and 
 an average length of the plurality of the masterbatches included in the masterbatch group is in a range from 2.0 to 4.0 mm. 
 
     
     
       8. A method for producing the masterbatch according to  claim 1 , the method comprising:
 mixing an aluminum paste, which is obtained by wetting the aluminum particles with the heat-resistant wetting agent, with the resin having a melt flow rate in a range from 0.2 to 60 g/10 min so as to produce an aluminum-resin mixture,
 wherein the aluminum-resin mixture has a ratio of the aluminum particles in a range from 50 to 80% by weight and a ratio of the wax having a melt flow rate in a range of more than 60 g/10 min and a melt viscosity at 140° C. of 15 to 8000 mPa·s in a range of 10% by weight or less; 
 
 extruding the aluminum-resin mixture; and 
 cutting the extruded aluminum-resin mixture. 
 
     
     
       9. The method for producing the masterbatch according to  claim 8 ,
 wherein the mixing is carried out without using a stirring member. 
 
     
     
       10. The method for producing the masterbatch according to  claim 8 ,
 wherein the mixing is carried out at a temperature in a range of 80° C. or lower, and 
 the extruding is carried out at a temperature in a range from 150° C. to 250° C. 
 
     
     
       11. The method for producing the masterbatch according to  claim 8 ,
 wherein the mixing is carried out using surface-coated aluminum particles as the aluminum particles. 
 
     
     
       12. A synthetic resin molded article,
 wherein the synthetic resin molded article is produced using the masterbatch according to  claim 1 .