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A resin composition comprises a copolymer (A) comprising ethylene as a major component produced with a single-site catalyst, and an ethylene-vinyl alcohol copolymer (B) having an ethylene content of 20-60 mol. % and a degree of hydrolysis of 95% or above, the resin composition satisfying the equatio

A resin composition comprises a copolymer (A) comprising ethylene as a major component produced with a single-site catalyst, and an ethylene-vinyl alcohol copolymer (B) having an ethylene content of 20-60 mol. % and a degree of hydrolysis of 95% or above, the resin composition satisfying the equation (1): A )}/{weight of ( B )}≦<99/1  (1)A preferred resin composition comprises a copolymer (A) which has a density of 0.90-0.94 g/cm 3 and the resin composition further comprises a carboxylic acid-modified polyolefin (C) and satisfies the equations (2) and (3): A )}/{(weight of ( B )}≦: 99/1  (2) ≦X ≦: 20/80  (3)wherein X={weight of (C)}/{total weight of (A) and (B)}.Another preferred resin composition comprises a copolymer (A) which has a density of 0.85-0.90 g/cm 3 , and which satisfies the equation (5): A )}/{weight of ( B )}≦40/60  (5)The resin composition has superior melt moldability, gas barrier properties, flexural fatigue resistance, and impact resistance. It can be used in the preparation of a multilayered structure to impart a good appearance, delamination resistance, transparency, impact resistance, and gas barrier properties to the structure.

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1. A resin composition which comprises a copolymer (A) comprising ethylene as a major component produced by using a single-site catalyst, and an ethylene-vinyl alcohol copolymer (B) having an ethylene content of 20 to 60 mol % and a degree of hydrolysis of 95% or above, wherein the ethylene-vinyl al

1. A resin composition which comprises a copolymer (A) comprising ethylene as a major component produced by using a single-site catalyst, and an ethylene-vinyl alcohol copolymer (B) having an ethylene content of 20 to 60 mol % and a degree of hydrolysis of 95% or above, wherein the ethylene-vinyl alcohol copolymer (B) contains a boron compound in an amount of 20 to 2000 ppm in terms of boron,said resin composition satisfying the following equation (1): 2. The resin composition as claimed in claim 1, wherein the copolymer (A) is an ethylene-α-olefin copolymer in which the α-olefin has 3 to 8 carbon atoms. 3. The resin composition as claimed in claim 1, wherein the copolymer (A) is an ethylene-α-olefin copolymer in which the α-olefin has an ethylene content of 50 wt. % or more. 4. The resin composition as claimed in claim 1, wherein the copolymer (A) has a molecular weight distribution (Mw/Mn) of not greater than 4. 5. The resin composition as claimed in claim 1, wherein the ethylene-vinyl alcohol copolymer (B) contains a phosphorus compound in an amount of 2 to 200 ppm in terms of phosphorus element. 6. The resin composition as claimed in claim 1, wherein the ethylene-vinyl alcohol copolymer (B) contains an alkali metal salt in an amount of 5 to 5000 ppm in terms of elemental alkali metal. 7. The resin composition as claimed in claim 1, wherein the copolymer (A) has a density of 0.90 to 0.94 g/cm 3 and the resin composition further comprises a carboxylic acid-modified polyolefin (C) and satisfies the following equations (2) and(3):wherein X={weight of (C)}/{total weight of(A) and (B)}. 8. The resin composition as claimed in claim 7, wherein resin particles comprising the ethylene-vinyl alcohol copolymer (B) and the carboxylic acid-modified polyolefin (C) are dispersed in a matrix of the copolymer (A), and have an average particle diameter not greater than 5 μm. 9. The resin composition as claimed in claim 1, wherein a melt flow rate Ma of the copolymer (A) and a melt flow rate Mb of the ethylene-vinyl alcohol copolymer (B) satisfy the following equation (4): ≦Ma/Mb ≦5  (4) 10. The resin composition as claimed in claim 1, which further comprises a hydrotalcite compound (D) in an amount of 0.0001 to 2% based on the total weight of (A) and (B). 11. The resin composition as claimed in claim 1, which further comprises a metal salt of higher aliphatic carboxylic acid (E) in an amount of 0.0001 to 2% based an the total weight of (A) and (B). 12. A multilayered structure which comprises a layer of the resin composition as claimed in claim 1, and a layer of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol % and a degree of hydrolysis of 95% or above. 13. The multilayered structure as claimed in claim 12, which further comprises at least one layer comprising an ethylene-α-olefin copolymer produced by using a single-site catalyst and having a density of 0.90 to 0.94 g/cm 3 , in which the α-olefin has 3 to 8 carbon atoms, and at least one layer comprising a carboxylic acid-modified polyolefin. 14. The multilayered structure as claimed in claims 12 , which is formed by coextrusion. 15. A resin composition which comprises a copolymer (A) comprising ethylene as a major component produced by using a single-site catalyst, and an ethylene-vinyl alcohol copolymer (B) having an ethylene content of 20 to 60 mol % and a degree of hydrolysis of 95% or above, said resin composition satisfying the following equation (1): 11). 16. The resin composition as claimed in claim 15, wherein the copolymer (A) is an ethylene-α-olefin copolymer in which the α-olefin has 3 to 8 carbon atoms. 17. The resin composition as claimed in claim 15, wherein the copolymer (A) is an ethylene-α-olefin copolymer in which the α-olefin has an ethylene content of 50 wt. % or more. 18. The resin composition as claimed in claim 15, wherein the copolymer ( A) has a molecular weight distribution (Mw/Mn) of not greater than 4. 19. The resin composition as claimed in claim 15, wherein the ethylene-vinyl alcohol copolymer (B) contains a phosphorus compound in an amount of 2 to 200 ppm in terms of phosphorus element. 20. The resin composition as claimed in claim 15, wherein the ethylene-vinyl alcohol copolymer (B) contains an alkali metal salt in an amount of 5 to 5000 ppm in terms of elemental alkali metal. 21. The resin composition as claimed in claim 15, wherein the copolymer (A) has a density of 0.90 to 0.94 g/cm 3 and the resin composition further comprises a carboxylic acid-modified polyolefin (C) and satisfies the following equations (2) and (3):wherein X={weight of (C)}/{total weight of(A) and (B)}. 22. The resin composition as claimed in claim 21, wherein resin particles comprising the ethylene-vinyl alcohol copolymer (B) and the carboxylic acid-modified polyolefin (C) are dispersed in a matrix of the copolymer (A), and have an average particle diameter not greater than 5 μm. 23. The resin composition as claimed in claim 15, wherein a melt flow rate Ma of the copolymer (A) and a melt flow rate Mb of the ethylene-vinyl alcohol copolymer (B) satisfy the following equation (4): ≦Ma/Mb ≦5.  (4) 24. The resin composition as claimed in claim 15, which further comprises a hydrotalcite compound (D) in an amount of 0.0001 to 2% based on the total weight of (A) and (B). 25. The resin composition as claimed in claim 15, which further comprises a metal salt of higher aliphatic carboxylic acid (E) in an amount of 0.0001 to 2% based on the total weight of (A) and (B). 26. A multilayered structure which comprises a layer of the resin composition as claimed in claim 15 and a layer of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol % and a degree of hydrolysis of 95% or above. 27. The multilayered structure as claimed in claim 26, which further comprises at least one layer comprising an ethylene-α-olefin copolymer produced by using a single-site catalyst and having a density of 0.90 to 0.94 g/cm 3 , in which the α-olefin has 3 to 8 carbon atoms, and at least one layer comprising a carboxylic acid-modified polyolefin. 28. The multilayered structure as claimed in claim 26, which is formed by coextrusion.