Process for the manufacture of reactive rubber process aids

A process for the manufacture of a rubber process aid comprising:

• extruding in an extruder three compositions in three axially spaced sections;
• 1) a first section addition and treatment comprising adding to a first section of the extruder a mixture of a first composition comprising vulcanized rubber powder and thermoplastic resin in a first section of the extruder, said thermoplastic resin being present in an amount from about 0.5 to about 6.0% by weight based on a total weight of the compositions, said thermoplastic resin being selected from the group consisting of low density polyethylene, polypropylene, ethylene vinyl acetate, high density polyethylene and mixtures thereof, and
• subjecting said mixture to a temperature in the range of about 80° C. to about 220° C. in the extruder;
• and
• 2) a second section addition and treatment comprising:
• a) adding to a second section of the extruder a second thermoplastic resin present in an amount of 0.5% to 50% by weight based on the total weight of the compositions, said second thermoplastic resin being selected from the group consisting of low density polyethylene, polypropylene, ethylene vinyl acetate, high styrene styrene butadiene rubber, high density polyethylene, and
• (b) subjecting the second section with said second thermoplastic resin in combination with the mixture flowing from the first section to a temperature of 120° C. to about 220° C. in the extruder, and
• 3) a third section addition and treatment comprising:
• (a) adding to a third section of the extruder a virgin polymer in an amount of 2.0% to 50% by weight of the total weight of the compositions;
• and
• (b) subjecting the third section with said virgin polymer in combination with the mixture and said second thermoplastic resin flowing from the second section to a temperature of 80° C. to about 220° C. in the extruder.

A process for the manufacture of a rubber process aid comprising:

• extruding in an extruder three compositions in three axially spaced sections;
• a first section addition and treatment comprising
• adding to a first section of the extruder a mixture of a first composition comprising vulcanized rubber powder, thermoplastic resin, oxidizing peptizing agent and rubber activators in a first section of said extruder:
• wherein said thermoplastic resin is present in an amount from about 0.5 to about 6.0% by weight based on a total weight of the compositions, said thermoplastic resin being selected from the group consisting of low density polyethylene, polypropylene, ethylene vinyl acetate, high density polyethylene and mixtures thereof;
• said oxidizing peptizing agent is present in an amount from about 0.01 to 6.0% by weight based on the weight of the vulcanized rubber powder, said oxidizing peptizing agent being selected from the group consisting of Diphenyl Guanadine, 2-Mercapto Benzothiazole, Dibenzothiazole disulphide and mixtures thereof and said rubber activators are present in an amount from about 0 to 10.0% by weight based on the weight of said vulcanized rubber powder, said rubber activators being Stearic Acid and Zinc Oxide;
• and
• subjecting said mixture to a temperature in the range of about 80° C. to about 220° C. in the extruder;
• and
• a second section addition and treatment comprising:
• a) adding to a second section of the extruder a second thermoplastic resin present in an amount of 0.5% to 50% by weight based on the weight of the total compositions, said second thermoplastic resin being selected from the group consisting of low density polyethylene, polypropylene, ethylene vinyl acetate, high styrene styrene butadiene rubber, high density polyethylene;
• and
• (b) subjecting the second section with said second thermoplastic resin in combination with the mixture flowing from the first section to a temperature of 120° C. to about 220° C. in the extruder;
• and
• a third section addition and treatment comprising:
• (a) adding to a third section of the extruder a virgin polymer present in an amount of 2.0% to 50% by weight of the total weight of the compositions, said virgin polymer being selected from the group consisting of Ethylene Propylene Diene Monomer (EPDM) rubber, Ethylene Propylene Rubber, Styrene Butadiene Rubber, Polybutadiene Rubber, Polyisoprene Rubber, Natural Rubber and mixtures thereof;
• (b) subjecting the third section with said virgin polymer in combination with the mixture and said second thermoplastic material flowing from the second section to a temperature of 80° C. to about 220° C. in the extruder;
• (c) cooling the extrusion;
• and
• (d) cutting a resulting extruded product to produce a free flowing, solid reactive rubber process aid for use in rubber compounding and processing.