Ethylene copolymer and ethylene/alpha-olefin copolymer composition and propylene polymer composition both containing the ethylene copolymer

An ethylene-based copolymer composition [II] characterized by containing the ethylene-based copolymer which satisfies the following conditions (b-1) to (b-3):

• (b-1) having temperature (Tm) at the maximum peak in the endothermic curve of the component soluble in decane at 64° C., measured by a differential scanning calorimeter (DSC), of 40 to 90° C.,
• (b-2) containing the component soluble in decane at 64° C. which contains the component soluble in decane at normal temperature at 1 to 70% by weight, and
• (b-3) containing the component soluble in decane at normal temperature which comprises (i) a recurring unit derived from ethylene and (ii) a recurring unit derived from an α-olefin of 4 or more carbon atoms, and in which a content of (i) the recurring unit derived from ethylene is 50 to 75% by mole.

A propylene-based copolymer composition [III] characterized by containing the propylene-based copolymer and satisfying the following conditions (c-1) to (c-3):

• (c-1) containing the component soluble in decane at 64° C. at 1 to 99% by weight which has a temperature (Tm) at the maximum peak in the endothermic curve, measured by a differential scanning calorimeter (DSC), of 40 to 90° C.,
• (c-2) containing the component soluble in decane at 64° C. which contains the component soluble in decane at normal temperature at 1 to 70% by weight, and
• (c-3) containing the component soluble in decane at normal temperature which comprises (i) a recurring unit derived from ethylene and (ii) a recurring unit derived from an α-olefin of 4 or more carbon atoms, and in which a content of (i) the recurring unit derived from ethylene is 50 to 75% by mole.

An ethylene/α-olefin copolymer composition comprising:

• 1 to 70% by weight of [A] a copolymer of ethylene and α-olefin of 4 to 20 carbon atoms which comprises (A-i) 50 to 70% by mole of (a) a recurring unit derived from ethylene and 30 to 50% by mole of (b) a recurring unit derived from an α-olefin of 4 to 20 carbon atoms, and 30 to 99% by weight of [B] an at least one of ethylene-based copolymer comprising (a) ethylene, (b) at least one selected from α-olefin of 4 to 20 carbon atoms and cyclic olefin-based compound, and
• having (B-i) a density of 0.870 to 0.895 g/cm3.

A propylene-based polymer composition comprised of the propylene-based polymer [C-1], ethylene/α-olefin copolymer [A] and ethylene-based copolymer [B], and characterized by:

• (i) containing said propylene-based polymer [C-1] at 99 to 1% by weight, and ethylene/α-olefin copolymer [A] and ethylene-based copolymer [B] at 1 to 99% by weight (total content of [A] and [B]), and
• (ii) having a content ratio of the ethylene/α-olefin copolymer [A] to the ethylene-based copolymer [B], i.e., [A]/[B] content ratio, is 1/99 to 70/30.