Microencapsulated rubber additive

Abstract

The invention relates to a rubber additive composition which contains at least one rubber additive (a), the at least one additive (a) being encased in coating material (b) accompanied by formation of microcapsules. The additive can in particular be sulphur or another vulcanization agent, a vulcanization accelerator and/or activator.

1 . Rubber additive composition which contains at least one rubber additive (a), 
 wherein the at least one additive (a) is encased in coating material (b) accompanied by formation of microcapsules.    
   
   
       2 . Composition according to  claim 1 , 
 wherein the additive (a) is selected from vulcanization chemicals, in particular vulcanization agents, vulcanization accelerators and accelerator activators.    
   
   
       3 . Composition according to  claim 1   wherein the additive (a) is sulphur.    
   
   
       4 . Composition according to  claim 1 , 
 wherein the vulcanization accelerator is selected from the group consisting of xanthates, dithiocarbamates, tetramethylthiram disulphide and other thiurams, thiazoles, sulphenamides, guanidines, thiourea derivatives and amine derivatives.    
   
   
       5 . Composition according to  claim 1 , 
 wherein the coating material (b) is insoluble in rubber or in rubber mixtures up to temperatures of 120 to 140° C., in particular up to roughly 130° C.    
   
   
       6 . Composition according to  claim 1 , 
 wherein the coating material (b) is soluble or melts at temperatures above 120 to 140° C., in particular above 130° C., in rubber or in rubber mixtures.    
   
   
       7 . Composition according to  claim 1 , 
 wherein the coating material (b) is selected from the group consisting of waxes, paraffins, polyethylene, ethylene-vinyl acetate copolymers, polyvinyl alcohols and mixtures of same.    
   
   
       8 . Composition according to  claim 1 , 
 wherein the microcapsules display a size of 1 to 75 μm, more preferably 3 to 30 μm and most preferably 5 to 8 μm.    
   
   
       9 . Composition according to  claim 1 , 
 wherein the additive in the capsule is liquid and/or solid.    
   
   
       10 . Composition according to  claim 1 , 
 wherein it contains    (a) 99 to 40 wt. -%, more preferably 80 to 50 wt. -% and most preferably 70 to 60 wt. -% additive and    (b) 1 to 60 wt. -%, more preferably 20 to 50 wt. -% and most preferably 30 to 40 wt. -% coating material.    
   
   
       11 . Process for the preparation of a rubber additive composition according to  claim 1 , 
 wherein a mixture which contains at least one additive and coating material in liquid, dissolved, suspended or emulsified form solidifies to form microcapsules.    
   
   
       12 . Process according to  claim 11 , 
 wherein the mixture is fed onto a rotating device and solidifies during the movement towards the outside and forms microcapsules.    
   
   
       13 . Process according to  claim 11 , 
 wherein the mixture forms microcapsules in a fluidized bed, in an emulsion or suspension, by spray-drying, by precipitation or by cooling and settling.    
   
   
       14 . Use of the rubber additive composition according to  claim 1 , for the preparation of rubber or rubber mixtures, in particular those for synthetic rubber production.  
   
   
       15 . Rubber, rubber mixture or rubber product which has been produced using a rubber additive composition according to  claim 1.