Masterbatches for Preparing Composite Materials with Enhanced Conductivity Properties, Process and Composite Materials Produced

Abstract

The present invention relates to a masterbatch to for use in a process of preparing a composite material, the masterbatch comprising a blend of a first amorphous polymer with carbon nanotubes, and at least 5% by weight of carbon nanotubes based on the total weight of the masterbatch, preferably from 5% to 15%, wherein the masterbatch exhibit a high load melt flow index HLMI1 of less than 40 g/10 min determined at 200° C. under a load of 21.6 kg according to ISO1133 and the first amorphous polymer has a melt flow index MFI1 of at least 10 g/10 min determined at 200° C. under a load of 5 kg according to ISO1133H. The invention also relates to the process for preparing such masterbatch and to process of preparing a composite material using said masterbatch.

1 .- 15 . (canceled) 
     
     
         16 . A process for preparing a composite material comprising a polymer composition and carbon nanotubes, characterized in that said polymer composition comprises a mixture of a first and a second amorphous polymer and the composite material comprises from 0.05 to 1.95% by weight of carbon nanotubes based on the total weight of the composite material as determined according to ISO 11358, and in that the composite material has a surface resistivity of at most 1×10 4  Ohm/sq, said process comprising the steps of:
 b. providing a masterbatch comprising a first amorphous polymer and at least 5%, and preferably from 5% to 15%, by weight of carbon nanotubes based on the total weight of the masterbatch as determined according to ISO 11358, and wherein the first amorphous polymer has a melt flow index MFI1 of at least 10 g/10 min determined at 200° C. under a load of 5 kg according to ISO1133H, wherein the first amorphous polymer is selected from the group consisting of polystyrene, modified-polystyrene, acrylonitrile-butadiene-styrene, polycarbonate, styrene acrylonitrile, poly(methyl methacrylate), poly(vinyl chloride), polybutadiene, polybutylene terephthalate, poly(p-phenylene oxide), polysulfone, polyethersulfone, polyethylenimine, polyphenylsulfone, acrylonitrile styrene acrylate and any combination thereof, wherein the masterbatch comprises at least 80% by weight of the first amorphous polymer, and wherein the masterbatch comprises a surface resistivity of at most 1×10 2  Ohm/sq as determined according to CEI 60167; 
 c. providing a second amorphous polymer having a glass transition temperature Tg2; 
 d. blending together the masterbatch and the second amorphous polymer by extrusion in an extruder at a barrel temperature ranging from Tg2+100° C. to Tg2+200° C., preferably ranging from Tg2+120° C. to Tg2+180° C., 
 the glass transition temperature being determined according to according to ISO 11357-2:2013. 
 
     
     
         17 . The process according to  claim 16  wherein the masterbatch comprises a blend of the first amorphous polymer with carbon nanotubes, at least 5% by weight of carbon nanotubes based on the total weight of the masterbatch as determined according to ISO 11358, and having a high load melt flow index HLMI1 of less than 40 g/10 min determined at 200° C. under a load of 21.6 kg according to ISO1133, the masterbatch being characterized in that the first amorphous polymer has a melt flow index MFI1 of at least 10 g/10 min determined at 200° C. under a load of 5 kg according to ISO1133H. 
     
     
         18 . The process according to  claim 16  characterized in that the process includes, before (b), a process of preparing the masterbatch comprising:
 a1 providing carbon nanotubes; 
 a2. providing an first amorphous polymer, said first amorphous polymer having a glass transition temperature Tg1, and a melt flow index MFI1 of at least 10 g/10 min determined at 200° C. under a load of 5 kg according to ISO1133H; 
 a3. blending together said carbon nanotubes and said first amorphous polymer by extrusion in an extruder at a barrel temperature ranging from Tg1 to Tg1+80° C., preferably Tg1+5° C. to Tg1+50 ° C., the glass transition temperature being determined according to ISO 11357-2:2013. 
 
     
     
         21 . The process according to  claim 16 , the first amorphous polymer having a melt flow index MFI1 and second amorphous polymer having a melt flow index MFI2, the process being characterized in that it further comprises the step of selecting the first and second amorphous polymer so that MFI1 has a value of at least twice the value of MFI2. 
     
     
         22 . The process according to  claim 16  characterized in that said composite material comprises from 0.05 to 0.95% by weight of carbon nanotubes based on the total weight of the composite material as determined according to ISO 11358. 
     
     
         23 . The process according to  claim 16 , wherein the first amorphous polymer further comprises 0.01 to 4.0 by weight of one or more additive based on the total weight of the masterbatch, the one or more additive being selected from waxes, tristearin, zinc stearate, calcium stearate, magnesium stearate, erucyl amide, oleic acid amide, ethylene-acrilyc acid copolymer, ethylene vinyl acetate copolymer and cetyl trimethyl ammonium bromide.