Co-extruded, multi-layer tubing made from polyamide and olefin polymer materials

A multi-layer, co-extruded tube comprising:

• (1) an inner layer comprising a polyamide selected from the group consisting of (a) nylon-6, (b) nylon-11, (c) a nylon-6/nylon-6,6 copolymer, (d) a nylon-6/nylon-12 copolymer, and (e) nylon-12,
• (2) a middle layer comprising:
• (a) greater than 1% but not greater than 15% of a graft copolymer comprising a polyolefin backbone to which is grafted a polymerized monomer selected from the group consisting of (i) an α,β-unsaturated aliphatic carboxylic acid or derivatives thereof, and (ii) an α,β-unsaturated alicyclic carboxylic acid or derivatives thereof,
• (b) about 15% to about 40% of a broad molecular weight distribution propylene polymer material, having a Mw/Mn of about 5 to about 60, a melt flow rate of about 0.5 to about 50 g/I10 min, and xylene insolubles at 25° C. of at least 94%,
• (c) about 20% to about 40% of a graft copolymer comprising a backbone of propylene polymer material to which are grafted polymerized monomers selected from the group consisting of (i) methyl methacrylate and methyl acrylate, and (ii) methyl methacrylate and methacrylic acid, and
• (d) about 20% to about 50% of an olefin copolymer rubber, wherein 2(a)+2(b)+2(c)+2(d)=100% by weight, and
• (3) an outer layer comprising:
• (a) about 25% to about 45% of a broad molecular weight distribution propylene polymer material, having a Mw/Mn of about 5 to about 60, a melt flow rate of about 0.5 to about 50 g/10 min, and xylene insolubles at 25° C. of at least 94%,
• (b) about 25% to about 45% of a graft copolymer comprising a backbone of propylene polymer material to which are grafted polymerized monomers selected from the group consisting of (i) methyl methacrylate and methyl acrylate, and (ii) methyl methacrylate and methacrylic acid, and
• (c) about 20% to about 50% of an olefin copolymer rubber, wherein 3(a)+3(b)+3(c)=100% by weight.