Polychloroprene latex composition and its production method

Abstract

A nonionic polychloroprene latex composition employing a polyvinyl alcohol as an emulsifier/dispersant has favorable chemical and mechanical stability but has a high viscosity, and therefore it has such drawbacks that its coating method is limited, and it is hardly made to have a high solid content. A polychloroprene latex composition which has a low viscosity and which can be made to have a high solid content, can be obtained by emulsion polymerization of chloroprene alone or chloroprene and a monomer copolymerizable with chloroprene in the presence of a polyvinyl alcohol and a nonionic emulsifier.

1 . A polychloroprene latex composition obtained by emulsion polymerization of chloroprene alone or chloroprene and a monomer copolymerizable with chloroprene, in the presence of a polyvinyl alcohol and a nonionic emulsifier represented by the formula: 
     
       
         
         
             
             
         
       
     
     wherein each of R and R′ is an alkyl group or an aryl group, and each of m and n is an integer). 
   
   
       2 . The polychloroprene latex composition according to  claim 1 , wherein the nonionic emulsifier has a HLB value of from 14 to 19. 
   
   
       3 . The polychloroprene latex composition according to  claim 1 , wherein the monomer copolymerizable with chloroprene is an ethylenically unsaturated carboxylic acid. 
   
   
       4 . The polychloroprene latex composition according to  claim 1 , wherein the polyvinyl alcohol has a saponification degree of from 60 to 98 mol %. 
   
   
       5 . The polychloroprene latex composition according to  claim 1 , wherein the total amount of the polyvinyl alcohol and the nonionic emulsifier is from 1 to 10 parts by mass, per 100 parts by mass of chloroprene alone, or the total amount of chloroprene and the monomer copolymerizable with chloroprene, and the ratio (mass ratio) of the polyvinyl alcohol/the nonionic emulsifier is within a range of from 0.5/99.5 to 99.5/0.5. 
   
   
       6 . The polychloroprene latex composition according to  claim 1 , which has a solid content concentration of from 45 to 75 mass %. 
   
   
       7 . The polychloroprene latex composition according to  claim 6 , which has a pH of from 6 to 9, and a viscosity of from 5 to 5,000 mPa·s. 
   
   
       8 . An adhesive employing the polychloroprene latex composition as defined in  claim 1 . 
   
   
       9 . The adhesive according to  claim 8 , wherein the gel content (toluene-insoluble matter) of a (co)polymer contained in the polychloroprene latex composition is from 3 to 30 mass %. 
   
   
       10 . A coating agent employing the polychloroprene latex composition as defined in  claim 1 . 
   
   
       11 . A method for producing the polychloroprene latex composition as defined in  claim 1 , which comprises emulsion polymerization of chloroprene alone, or chloroprene and a monomer copolymerizable with chloroprene, in the presence of a polyvinyl alcohol and the nonionic emulsifier. 
   
   
       12 . An adhesive employing the polychloroprene latex composition as defined in  claim 1 , wherein the chloroprene is polymerized alone. 
   
   
       13 . An adhesive employing the polychloroprene latex composition as defined in  claim 1 , wherein the chloroprene is polymerized with the monomer copolymerizable with chloroprene.