Multilayer structure and tank consisting of this structure, which has a barrier layer in direct contact with the fluid contained

Abstract

The present invention relates to a structure comprising, successively: a first layer of high density polyethylene (HDPE), a layer of binder, a second layer of EVOH or of a mixture based on EVOH, optionally a third layer of polyamide (A) or of a mixture of polyamide (A) and polyolefin (B). The present invention also relates to devices for transferring or storing fluids and more particularly tubes, tanks, chutes, bottles and containers consisting of the above structure and in which the barrier layer (the second or the combination of the second and the third layer) is in direct contact with the fluid contained or transported.

1 - 18 . (canceled)  
     
     
         19 . A device for transferring and/or storing a liquid containing volatile substances, comprising: a multi-layer structure in a shape capable of holding the liquid, the multi-layer structure having, successively: 
 a first layer of high density polyethylene (HDPE)    a layer of binder,    a second layer of an ethylene-vinyl alcohol copolymer or of a mixture based on an ethylene-vinyl alcohol copolymer, and    a third layer of a polyamide (A) or a mixture of a polyamide (A) and a polyolefin (B),    wherein the third layer is provided in the structure such that the fluid stored and/or transferred therein is in contact with this layer.    
     
     
         20 . A device according to  claim 19 , further comprising a layer of binder between the second and the third layer.  
     
     
         21 . A device according to  claim 19 , in which the binder comprises: 
 5 to 30 parts by weight per hundred of a polymer (D) which itself comprises a mixture of a polyethylene (D1) with a density of from 0.910 to 0.940 g/cm 3  and of    a polymer (D2) selected from the group consisting of elastomers, very low density polyethylenes and metallocene polyethylenes, the mixture (D1)+(D2) being co-grafted with an unsaturated carboxylic acid,    95 to 70 parts by weight per hundred of a polyethylene (E) with a density of from 0.910 to 0.930 g/cm 3 ,    the mixture of (D) and (E) being such that: 
 its density is from 0.910 to 0.930 g/cm 3 ,  
 the content of grafted unsaturated carboxylic acid is between 30 and 10,000 ppm, and  
 the melt flow index, measured by ASTM D 1238, at 190° C. and 2.16 kg, is between 0.1 and 3 g/10 min.  
   
     
     
         22 . A device according to  claim 21 , in which the density of the binder is from 0.915 to 0.920 g/cm 3 .  
     
     
         23 . A device according to  claim 21 , in which (D1) and (E) are LLDPEs which have the same comonomer.  
     
     
         24 . A device according to  claim 19 , in which the binder comprises: 
 5 to 30 parts by weight per hundred of a polymer (F) which itself comprises a mixture of a polyethylene (F1) with a density of from 0.935 to 0.980 g/cm 3  and of a polymer (F2) selected from the group consisting of elastomers, very low density ATOCM-197-D 1 polyethylenes and ethylene copolymers, the mixture (F1)+(F2) being co-grafted with an unsaturated carboxylic acid,    95 to 70 parts by weight per hundred of a polyethylene (G) with a density of from 0.930 to 0.950 g/cm 3 ,    the mixture of (F) and (G) being such that: 
 its density is from 0.930 to 0.950 g/cm 3 ,  
 the content of grafted unsaturated carboxylic acid is between 30 and 10,000 ppm,  
 the metal flow index, measured by ASTM D 1238 at 190° C. and 21.6 kg, is between 5 and 100 g/10 min.  
   
     
     
         25 . A device according to  claim 19 , in which the binder is a polyethylene grafted with maleic anhydride, having a melt flow index, measured by ASTM D 1238 at 190° C. and 21.6 kg, of 0.1 to 3 g/10 min, and a density of from 0.920 to 0.930 g/cm 3 .  
     
     
         26 . A device according to  claim 19 , in which the binder is a mixture consisting of a HDPE, LLDPE, VLDPE or LDPE polyethylene, 5 to 35% by weight of a grafted metallocene polyethylene and 0 to 35% by weight of an elastomer, based on a total of 100% by weight.  
     
     
         27 . A device according to  claim 19 , in which the polyamide of the third layer is a copolyamide.  
     
     
         28 . A device according to  claim 19 , wherein the third layer comprises, mixed with the polyamide (A), a polyolefin (B) which comprises: 
 a high density polyethylene and    a mixture of a polyethylene (C1) and a polymer (C2) selected from the group consisting of elastomers, very low density polyethylenes and ethylene copolymers, the mixture (C1)+(C2) being co-grafted with an unsaturated carboxylic acid.    
     
     
         29 . A device according to  claim 19 , wherein the third layer comprises, mixed with the polyamide (A), a polyolefin (B) which comprises: 
 a high density polyethylene,    a polymer (C2) selected from the group consisting of elastomers, very low density polyethylenes and ethylene copolymers, the polymer (C2) being grafted with an unsaturated carboxylic acid and    a polymer (C′2) selected from the group consisting of elastomers, very low density polyethylenes and ethylene copolymers.    
     
     
         30 . A device according to  claim 19 , in which the polyamide (A) of the third layer is selected from the group consisting of: 
 mixtures of (i) a polyamide and (ii) a copolymer containing polyamide-6 blocks and polytetramethylene glycol blocks, and    mixtures of (i) a polyamide and (ii) a copolymer containing polyamide-12 blocks and polytetramethylene glycol blocks,    the weight ratio of the amounts of copolymers (ii) and polyamides (i) being from 10:90 to 60:40.    
     
     
         31 . A device according to  claim 30 , in which the third layer comprises a polyolefin B, which comprises (i) a LLDPE, VLDPE or metallocene polyethylene and (ii) an ethylene-alkyl (meth)acrylate-maleic anhydride copolymer.  
     
     
         32 . A device according to  claim 30 , in which the third layer comprises a polyolefin (B) which comprises two functionalized polymers comprising at least 50 mol % of ethylene units and is crosslinkable.  
     
     
         33 . A device according to  claim 20 , in which the binder comprises: 
 5 to 30 parts by weight per hundred of a polymer (D) which itself comprises a mixture of a polyethylene (D1) with a density of from 0.910 to 0.940 g/cm 3  and of a polymer (D2) selected from the group consisting of elastomers, very low density polyethylenes and metallocene polyethylenes, the mixture (D1)+(D2) being co-grafted with an unsaturated carboxylic acid,    95 to 70 parts by weight per hundred of a polyethylene (E) with a density of from 0.910 to 0.930 g/cm 3 ,    the mixture of (D) and (E) being such that: 
 its density is from 0.910 to 0.930 g/cm 3 ,  
 the content of grafted unsaturated carboxylic acid is between 30 and 10,000 ppm, and  
 the melt flow index, measured by ASTM D 1238 at 190° C. and 2.16 kg, is between 0.1 and 3 g/10 min.  
   
     
     
         34 . A device according to  claim 20 , in which the binder comprises: 
 5 to 30 parts by weight per hundred of a polymer (F) which itself comprises a mixture of a polyethylene (F1) with a density of from 0.935 to 0.980 g/cm 3  and of a polymer (F2) selected from the group consisting of elastomers, very low density polyethylenes and ethylene copolymers, the mixture (F1)+(F2) being co-grafted with an unsaturated carboxylic acid,    95 to 70 parts by weight per hundred of a polyethylene (G) with a density of from 0.930 to 0.950 g/cm 3 , the mixture of (F) and (G) being such that: 
 its density is from 0.930 to 0.950 g/cm 3 ,  
 the content of grafted unsaturated carboxylic acid is between 30 and 10,000 ppm,  
 the melt flow index, measured by ASTM D 1238 at 190° C. and 21.6 kg, is between 5 and 100 g/10 min.  
   
     
     
         35 . A device according to  claim 19 , wherein the device is a tube, a tank, a chute, or a bottle.  
     
     
         36 . A device according to  claim 19 , wherein the device is a container.  
     
     
         37 . A device according to  claim 28 , in which the third layer comprises: 
 60 to 70% by weight of polyamide (A),    5 to 15% by weight of the co-grafted mixture of polyethylene (C1) and polymer (C2), and    the remainder of high density polyethylene.    
     
     
         38 . A device according to  claim 29 , in which the third layer comprises: 
 60 to 70% by weight of polyamide (A)    5 to 10% by weight of the grafted polymer (C2),    5 to 10% by weight of polymer (C′2), and    the remainder of high density polyethylene.    
     
     
         39 . A device according to  claim 19 , wherein the polyamide (A) in the third layer is a PA 6/6-6 copolymer of caprolactam, adipic acid and hexamethylenediamine.  
     
     
         40 . A device according to  claim 19 , wherein the first layer has a thickness between 2 and 10 mm, the second layer between 30 and 500 μm and the third layer between 30 μm and 2 mm.  
     
     
         41 . A device according to  claim 19 , wherein the device is designed for storing and/or transporting a fluid selected from the group consisting of petrol, oil, motor vehicle cooling fluid and air conditioning fluid.  
     
     
         42 . A device according to  claim 19 , wherein the device is designed for storing and/or transporting petrol.  
     
     
         43 . A device according to  claim 19 , wherein the multi-layer structure consists essentially of: 
 the first layer of high density polyethylene (HDPE),    the layer of binder,    the second layer of an ethylene-vinyl alcohol copolymer or of a mixture based on an ethylene-vinyl alcohol copolymer,    the third layer of a mixture of a polyamide (A) and a polyolefin (B), and    optionally, a layer of binder between the second layer and third layer.