Process for the preparation of polyolefin nanocomposites

Abstract

The instant invention discloses a process for the preparation a polyolefin nanocomposite which comprises melt mixing a mixture of a polyolefin, a filler and a non-ionic surfactant.

1 . A process for the preparation of a polyolefin nanocomposite which comprises melt mixing a mixture of a) a polyolefin, b) a filler and c) a non-ionic surfactant.  
     
     
         2 . A process according to  claim 1 , wherein the filler is a natural or synthetic phyllosilicate or a mixture of such phyllosilicates or a layered hydroxycarbonate.  
     
     
         3 . A process according to  claim 1 , wherein the filler is a layered silicate clay or a layered hydroxycarbonate.  
     
     
         4 . A process according to  claim 1 , wherein the filler is a montmorillonite, bentonite, beidellite, mica, hectorite, saponite, nontronite, sauconite, vermiculite, ledikite, magadite, kenyaite, stevensite, volkonskoite, hydrotalcite or a mixture thereof.  
     
     
         5 . A process according to  claim 1 , wherein the non-ionic surfactant is a block or graft copolymer containing a hydrophilic and a hydrophobic segment which do not contain an onium functionality.  
     
     
         6 . A process according to  claim 5 , wherein the hydrophilic segment is a poly(ethylene oxide) block and the hydrophobic segment is a branched or unbranched polyolefin, a fluorocarbon, a siloxane or a low molecular weight methacrylate.  
     
     
         7 . A process according to  claim 1 , wherein the non-ionic surfactant is a sorbitan ester, a di-methylsiloxane-ethylene oxide-block copolymer, a poly(methyl methacrylate)-block-poly(oxyethylene) copolymer or a compound of the formula I  
       
         
           
           
               
               
           
         
       
       wherein 
 m is 1 or 2,  
 n is 1 or 2,  
 x is greater than or equal to 1,  
 y is greater than or equal to 1,  
 z is greater than or equal to 0, and  
 R 1  is hydrogen or C 1 -C 25 alkyl.  
 
     
     
         8 . A process according to  claim 7 , wherein the sorbitan ester is an ester of sorbitol or an ethoxylated sorbitan with a C 12 -C 25 carboxylic acid.  
     
     
         9 . A process according to  claim 1 , wherein the polyolefin is polyethylene or polypropylene or copolymers thereof.  
     
     
         10 . A process according to  claim 1 , wherein the filler is present in an amount of from 1 to 15%, based on the weight of the polyolefin.  
     
     
         11 . A process according to  claim 1 , wherein the non-ionic surfactant is present in an amount of from 0.1 to 7.5%, based on the weight of the polyolefin.  
     
     
         12 . A process according to  claim 1 , wherein the melt mixing occurs between 120 and 290° C.  
     
     
         13 . A process according to  claim 1 , comprising in addition, besides components (a), (b) and (c), further additives.  
     
     
         14 . A process according to  claim 13 , comprising as further additives phenolic antioxidants, light-stabilizers, processing stabilizers, pigments, dyes, plasticizers, compatibilizers, toughening agents, thixotropic agents, levelling assistants, acid scavengers and/or metal passivators.  
     
     
         15 . A process according to  claim 1 , wherein the mixture of the filler and the non-ionic surfactant, and where applicable further additives, are added to the polyolefin in the form of a master batch which contains the mixture in a concentration of from 2.5 to 40% by weight.  
     
     
         16 . A polyolefin nanocomposite obtained by a process according to  claim 1 .  
     
     
         17 . A nanocomposite comprising 
 a) a polyolefin which is susceptible to oxidative, thermal or light-induced degradation,    b) a filler,    c) a non-ionic surfactant, and    d) an additive selected from the group consisting of phenolic antioxidants, light-stabilizers, processing stabilizers, pigments, dyes, plasticizers, compatibilizers, toughening agents, thixotropic agents, levelling assistants, acid scavengers and metal passivators or mixtures thereof.    
     
     
         18 . An article from polyolefin nanocomposite prepared according to  claim 1 .  
     
     
         19 . Use of a non-ionic surfactant to intercalate and exfoliate a filler and disperse the filler in a polyolefin matrix to form a nanocomposite.