Multilayer structure having a layer based on polyamide and on HDPE

Abstract

The present invention relates to a structure successively comprising: a first layer of high density polyethylene (HDPE), a tie layer, a second layer of EVOH or of a blend based on EVOH, optionally a tie layer, a third layer of a blend comprising, by weight, the total being 100%: 50 to 90% of polyamide (A) having a conversion temperature of at most 230° C., 1 to 30% of high density polyethylene (HDPE), 5 to 30% of an impact modifier chosen from elastomers and very low density polyethylenes, at least one of the HDPE and of the impact modifier being functionalized, in all or part, the layers being coextrudable. The present invention also relates to devices for the transfer or storage of fluids and more particularly to pipes, tanks, conduits, bottles and containers composed of the above structure in which the layer of the blend of polyamide (A) and of HDPE is in direct contact with the fluid present or transported

1 . A structure comprising in order: 
 a) a first layer of high density polyethylene (HDPE),    b) a tie layer,    c) a second layer of EVOH or of a blend based on EVOH,    d) optionally a tie layer,    e) a third layer of a blend comprising, by weight, the total being 100%: 
 50 to 90% of polyamide (A) having a conversion temperature of at most 230° C.,  
 1 to 30% of high density polyethylene (HDPE),  
 5 to 30% of an impact modifier chosen from elastomers and very low density polyethylenes,  
 wherein the HDPE and/or the impact modifier is functionalized, in whole or in part, wherein the layers are coextrudable.  
   
     
     
         2 . The structure according to  claim 1 , wherein said polyamide (A) is polyamide 6/6-6 or polyamide 6/12.  
     
     
         3 . The structure according to  claim 1 , wherein the proportion of functionalized HDPE and/or of functionalized modifier with respect to the combined functionalized or nonfunctionalized HDPE and functionalized or nonfunctionalized impact modifier in the third layer (e) is between 0 and 70 percent by weight.  
     
     
         4 . The structure according to  claim 3 , wherein the proportion of functionalized HDPE and/or of functionalized modifier with respect to the combined functionalized or nonfunctionalized HDPE and functionalized or nonfunctionalized impact modifier in the third layer (e) is between 5 and 60 percent by weight.  
     
     
         5 . The structure according to  claim 4 , in which the proportion of functionalized HDPE and/or of fuctionalized modifier with respect to the combined functionalized or nonfunctionalized HDPE and functionalized or nonfunctionalized impact modifier in the third layer (e) is between 20 and 60 percent by weight.  
     
     
         6 . The structure according to  claim 1 , wherein in layer (e) the HDPE is not functionalized and the impact modifier is functionalized in all or part.  
     
     
         7 . The structure according to  claim 1 , wherein the impact modifier is an ethylene-propylene rubber (EPR) or an ethylene-propylene-diene monomer elastomer (EPDM).  
     
     
         8 . The structure according to  claim 1 , wherein the functionalized impact modifier is an EPR or an EPDM grafted by maleic anhydride.  
     
     
         9 . The structure according to  claim 1 , wherein the proportions of the blend of the third layer are, the total being 100%: 
 55 to 80% of polyamide (A),    10 to 20% of high density polyethylene (HDPE),    10 to 30% of impact modifier.    
     
     
         10 . The structure according to  claim 1 , in which a layer of recycled polymers is positioned between the first layer and the tie layer.  
     
     
         11 . The structure according to  claim 10 , in which the layer of recycled polymers further comprises HDPE and/or functionalized polyolefins.  
     
     
         12 . A devices for the transfer or storage of fluids comprising the structure according to  claim 1 , in which the third layer (e) is in direct contact with the fluid present or transported.  
     
     
         13 . The device according to  claim 12  wherein said device is selected from the group consisting of a pipe, a tank, a conduit, a bottle, and a container.