Process for the treatment of the photopolymer material that constitutes the matrix plates in flexographic printing

A process for treating photopolymer material that makes up master plates in flexographic printing, the method comprising:

• shredding and refining the plates into pieces smaller than 10 mm in any direction;
• subsequent cold grinding of the flexographic photopolymer plate pieces at a temperature between −35 °C and −140 °C to obtain a powder with a particle size ranging from 100 to 500 microns;
• drying the powder at a temperature of 80-120 °C for two hours;
• introducing the dried powder into a twin-screw extruder with co-rotating screws with rotation of the screws between 150 and 250 rpm where the dried powder is mass mixed with a polymer melt at a temperature of 160-300 °C;
• collecting at an exit of the extruder a homogeneous mass mixture of polymer melt and powder which is collected in the form of an extruded wire which is cooled in air at a temperature of about 25 °C or in water at a temperature of about 15 °C;
• and
• pelletizing the extruded wire.