Polyolefin composition with increased resistance to cio2-containing water

Abstract

The present invention relates to a polyolefin composition comprising a polyolefin base resin and an antioxidant, characterized in that said polyolefin composition has a lifetime of at least 200 h in a test measuring the resistance against ClO 2 -containing water at 90° C., and at a concentration of ClO 2 of 4 ppm wherein the equipment used is according to ASTM F2263-03. The present invention further relates to a pipe comprising the polyolefin composition according to the invention, to the use of the polyolefin composition for the production of a pipe, and to the use of a particularly selected antioxidant for increasing the resistance of a polyolefin composition against degradation caused by contact with ClO 2 -containing water.

1 . A polyolefin composition comprising a polyolefin base resin and an antioxidant, characterized in that said polyolefin composition has a lifetime of at least 200 h in a test measuring the resistance against ClO 2 -containing water at 90° C. and at a concentration of ClO 2  of 4 ppm wherein the equipment used is according to ASTM F2263-03.
 wherein the antioxidant is selected from   a) the group of phenols according to formula I:   
     
       
         
         
             
             
         
       
       
         wherein 
         R is a non-substituted or substituted aliphatic or aromatic hydrocarbyl radical which may comprise heteroatoms or R is a heteroatom, 
         R′ and R″ independently are a non-substituted or substituted hydrocarbyl radical which may comprise heteroatoms or H, 
         X 1 , X 2  and X 3  independently are a non-substituted or substituted hydrocarbyl radical which may comprise heteroatoms or H or OH, with at least X 1 , X 2  or X 3  being OH, 
         n is 1 to 4, and 
         at least one of the substituents R, R′ and/or R″ of the phenol comprises at least one sulphur heteroatom(s), 
         or is selected from 
       
       b) the amine compounds according to formula II: 
     
     
       
         
         
             
             
         
       
       
         wherein R 1 , R 2 , R 3 , R 4 , R 5  and R 6  independently are hydrogen or an aliphatic or aromatic hydrocarbyl radical, optionally comprising heteroatoms, 
       
       or is selected from 
       c) the sulphur-containing compounds according to formula III:
   R a —S—R b , 
 wherein R a  and R b  independently are an aliphatic or aromatic hydrocarbyl radical, optionally comprising heteroatoms. 
 
     
   
   
       2 . The polyolefin composition according to  claim 1  wherein the polyolefin base resin comprises an ethylene homo- or copolymer. 
   
   
       3 . The polyolefin composition according to  claim 1  wherein the amount of antioxidant in the polyolefin composition is 5000 ppm or less. 
   
   
       4 . The polyolefin composition according to  claim 3  wherein the amount of antioxidant in the polyolefin composition is 3500 ppm or less. 
   
   
       5 . The polyolefin composition according to  claim 4  wherein the amount of antioxidant in the polyolefin composition is 2500 ppm or less. 
   
   
       6 . A pipe comprising a polyolefin composition according to  claim 1 . 
   
   
       7 - 10 . (canceled) 
   
   
       11 . A method for producing a pipe comprising the polyolefin composition according to  claim 1 . 
   
   
       12 . A method for drinking water transportation comprising a pipe comprising a polyolefin composition according to  claim 1 . 
   
   
       13 . The method according to  claim 12  wherein the drinking water contains ClO 2 . 
   
   
       14 . A method for increasing the resistance of a polyolefin composition against degradation caused by contact with ClO2-containing water using an antioxidant selected from
 a) the group of phenols according to formula I:   
     
       
         
         
             
             
         
       
       
         wherein 
         R is a non-substituted or substituted aliphatic or aromatic hydrocarbyl radical which may comprise heteroatoms or R is a heteroatom, 
         R′ and R″ independently are a non-substituted or substituted hydrocarbyl radical which may comprise heteroatoms or H, 
         X 1 , X 2  and X 3  independently are a non-substituted or substituted hydrocarbyl radical which may comprise heteroatoms or H or OH, with at least X 1 , X 2  or X 3  being OH, 
         n is 1 to 4, and 
         at least one of the substituents R, R′ and/or R″ of the phenol comprises at least one sulphur, phosphorus and/or nitrogen heteroatom(s), 
       
       or selected from 
       b) the amine compounds according to formula II: 
     
     
       
         
         
             
             
         
       
       
         wherein R 1 , R 2 , R 3 , R 4 , R 5  and R 6  independently are hydrogen or an aliphatic or aromatic hydrocarbyl radical, optionally comprising heteroatoms, 
         or selected from 
       
       c) the sulphur-containing compounds according to formula III:
   R a —S—R b , 
 wherein R a  and R b  independently are an aliphatic or aromatic hydrocarbyl radical, optionally comprising heteroatoms.