Nano-sized diene-based polymer latex particles

Abstract

The present invention refers to diene-based unsaturated polymer latex particles having a particle size measured as d 90 -value of less than 60 nm and a method for their production.

1 . Diene-based unsaturated polymer latex particles having a particle size measured as d 90 -value of less than 60 nm. 
     
     
         2 . Latex particles according to  claim 1 , wherein the diene-based latex particles are acrylonitrile/butadiene polymers. 
     
     
         3 . Method for producing diene-based unsaturated polymers in latex form comprising
 a) polymerization of at least one diene D and optionally at least one copolymerisable monomer A   b) in an aqueous medium, preferably water,   c) in the presence of a surfactant, preferably an alkyl sulphate, wherein   d) diene D and optionally at least one copolymerisable monomer A are continuously charged into a reactor containing the aqueous medium, a polymerisation initiator and the surfactant, preferably in slow and steady feeding rate.   
     
     
         4 . Method according to  claim 3 , wherein the diene D is 1,3-butadiene and wherein at least one copolymerizable monomer A is reacted. 
     
     
         5 . Method according to  claim 3 , wherein the copolymerizable monomer A is acrylonitrile. 
     
     
         6 . Method according to  claim 3 , wherein the polymerization is performed in the presence of a surfactant in an amount of 0.1% to 1% in weight based on the total monomer amount used. 
     
     
         7 . Method according to  claim 3 , wherein the obtained diene-based latex particles have a diameter measured as d 90 -value of less than 60 nm. 
     
     
         8 . Method according to  claim 3 , wherein the polymerization initiator is a redox initiator, preferably a persulfate. 
     
     
         9 . Method according to  claim 3 , wherein the surfactant is an alkylsulfate. 
     
     
         10 . Method for hydrogenation of unsaturated diene-based polymers, wherein diene-based latex particles according to  claim 1  are hydrogenated. 
     
     
         11 . Rubber or rubber intermediate comprising a polymer according to  claim 1 .