Membranes

A membrane comprising a layer (A) and a layer (B), where the layer (A) comprises a composition (i) comprising the following polymer components, all percent amounts being by weight:

• a) 10-40% of one or more propylene polymers selected from propylene homopolymers, copolymers of propylene with ethylene or a CH2═CHR α-olefin, where R is a C2-C8 alkyl radical, and copolymers of propylene with ethylene and said CH2═CHR α-olefin, said copolymers containing over 85% of propylene and having a fraction insoluble in xylene at room temperature greater than 80%;
• and
• b) 60-90% of one or more copolymers selected from (b1) copolymers of ethylene with propylene or a CH2═CHR α-olefin, where R is a C2-C8 alkyl radical, and optionally minor quantities of a diene, and (b2) copolymers of ethylene with propylene and said α-olefin, and optionally minor quantities of a diene, said copolymers containing ethylene in a quantity lower than 40%, and having solubility in xylene at room temperature greater than 70%;
• the amounts of (a) and (b) being referred to the total weight of (a) and (b);
• and the layer (B) comprises an ethylene homopolymer or copolymer having density from 0.915 to 0.980 g/cm3, measured according to ISO 1183, or a combination of two or more homopolymers or copolymers as defined above;
• said layer (B) being at least partially bonded to the layer (A).