Permeation-inhibiting members and multi-layer containers made by using the same

A permeation-preventive member for preventing a permeation of hydrocarbon compound by fusion-bonding the member to a discontinuous part of the permeation-preventive layer in a multilayered container for fuel tank which comprises an inner polyolefin resin layer, an outer polyolefin resin layer and a permeation-preventive layer as an interlayer, wherein the permeation-preventive member comprises a metal sheet or foil and an adhesive resin layer that satisfies the following requirements (a) to (e):

• (a) the melt flow rate as measured at a temperature of 190° C. under a load of 2.16 kg is 0.1-1.5 g/10 min;
• (b) the density is 0.930-0.960 g/cm3;
• (c) the initial adhesive strength to the metal sheet or foil is 0.1 kg/10 mm or higher;
• (d) the adhesive strength to the metal sheet or foil as measured after 2,500-hour immersion at 65° C. in a mixed solvent composed of 45 parts by volume of 2,2,4-trimethylpentane, 45 parts by volume of toluene, and 10 parts by volume of ethyl alcohol is 0.1 kg/10 mm or higher;
• and
• (e) the proportion of the adhesive strength (d) to the initial adhesive strength (c) is 50% or higher,
• wherein the metal constituting the metal sheet or foil is aluminum,
• wherein the adhesive resin comprises a polyethylene modified with an unsaturated carboxylic acid or a derivative thereof (A), and unmodified polyethylene (B), and the proportion of the modified polyethylene (A) to the unmodified polyethylene (B) is in the range of from 15/85 to 85/15 in terms of (A)/(B) ratio by mass, and MFR(A)/MFR(B) is smaller than 0.6 where the MFR(A) is a melt flow rate of the modified polyethylene (A) measured at a temperature of 190° C. under a load of 2.16 kg and the MFR(B) is a melt flow rate of the unmodified polyethylene (B) measured at a temperature of 190° C. under a load of 2.16 kg, and
• wherein the modified polyethylene (A) is obtained by grafting an unsaturated carboxylic acid and/or a derivative thereof in an amount of 0.1-20 parts by mass onto 100 parts of polyethylene which has a density is 0.920-0.965 g/cm3 and a melt flow rate as measured at a temperature of 190° C. under a load of 2.16 kg of 0.1-1.5 g/10 min,
• and the unmodified polyethylene (B) has a density is 0.915-0.960 g/cm3 and a melt flow rate as measured at a temperature of 190° C. under a load of 2.16 kg of 0.1-3.0 g/10 min.