Method for making masterbatch

Abstract

A process for producing a colouring agent (masterbatch) for colouring a polymer is provided, comprising the step of mixing a plastics material, carbon black and waste print powder. The maximum proportion of waste print powder is preferably 50%. The process enables waste print powder to be recycled in a useful manner, thereby addressing the environmental problem of waste print powder pollution.

1 . A process for producing a colouring agent for colouring a polymer, comprising the step of mixing a plastics material, carbon black and waste print powder.  
     
     
         2 . A process as claimed in  claim 1 , wherein the proportion by weight of the components is from 5 to 95% plastics material, from 0.5 to 80% carbon black, and from 5 to 80% waste print powder.  
     
     
         3 . A process as claimed in  claim 2 , wherein the said proportions are from 20 to 50% plastics material, from 20 to 40% carbon black and from 25 to 50% waste print powder.  
     
     
         4 . A process as claimed in  claim 2 , wherein the said proportions are about 25% plastics material, about 25% carbon black and about 40% waste print powder.  
     
     
         5 . A process as claimed in any preceding claim, wherein the components are added to a mixer, and wherein the entrance to the mixer is maintained at a temperature of from 40 to 90° C. to prevent softening of the waste print powder.  
     
     
         6 . A process as claimed in  claim 5 , wherein the mixer entrance is maintained at about 45° C.  
     
     
         7 . A process as claimed in any preceding claim, wherein the components are mixed at a temperature of from 135 to 230° C.  
     
     
         8 . A process as claimed in  claim 7 , wherein the components are mixed at about 150° C.  
     
     
         9 . A process as claimed in any preceding claim, wherein the components are mixed in a twin screw extruder, a Farrel CP machine, a Banbury mixer, a single screw extruder, or a two roll mill.  
     
     
         10 . A process as claimed in  claim 9 , wherein the components are mixed at a mixing rate of from 150 to 500 min −1 .  
     
     
         11 . A process as claimed in any preceding claim, wherein after the components are mixed to form the colouring agent, said agent is extruded and divided into pellets for use in the colouring of a second plastics material.  
     
     
         12 . A colouring agent for colouring a polymer which agent is obtainable by means of a process according to any preceding claim.  
     
     
         13 . A process for forming a coloured object from a plastics material, comprising the steps of mixing said plastics material with a colouring agent as claimed in  claim 12 , and forming the coloured plastics material into said object.  
     
     
         14 . A process as claimed in  claim 13 , wherein said object is formed by extruding said plastics material with said colouring agent.  
     
     
         15 . A process as claimed in any preceding claim, wherein the waste print powder melts at about 118° C. and solidifies at about 118.75° C.  
     
     
         16 . An object formed from a plastics material, which material has been coloured by the addition of a colouring agent as claimed in  claim 12.