Stretched laminated film
Disclosed is a stretched laminated film 30 having a heat-sealable layer 10 composed of a resin composition which contains 50 to 97 parts by mass of a propylene-based polymer (A) having a melting point (Tm) of not lower than 120° C. but not higher than 170° C. and comprising more than 50% by mol of a structural unit derived from propylene, 3 to 50 parts by mass of a 1-butene-based polymer (B) having a melting point (Tm) of lower than 120° C. and comprising 10 to 90% by mol of a structural unit derived from 1-butene and 10 to 90% by mol of a structural unit derived from an α-olefin having 3 or 5 to 20 carbon atoms, and optionally 3 to 30 parts by mass of an ethylene α-olefin copolymer (C) comprising 50 to 99% by mol of a structural unit derived from ethylene and 1 to 50% by mol of a structural unit derived from an α-olefin having 3 to 20 carbon atoms, wherein the sum of the component (A) and the component (B) is 100 parts by mass; and a base layer 20.
1. A stretched laminated film having
a heat-sealable layer composed of a resin composition which contains
50 to 97 parts by mass of a propylene-based polymer (A) having a melting point (Tm) of not lower than 120° C. but not higher than 170° C. measured by differential scanning calorimetry (DSC), and comprising more than 50% by mol of a structural unit derived from propylene,
3 to 50 parts by mass of a 1-butene-based polymer (B) having a melting point (Tm) of lower than 120° C. measured by differential scanning calorimetry (DSC), and comprising 10 to 90% by mol of a structural unit derived from 1-butene and 10 to 90% by mol of a structural unit derived from an α-olefin having 3 or 5 to 20 carbon atoms, wherein the sum of the structural unit derived from 1-butene and the structural unit derived from an α-olefin having 3 or 5 to 20 carbon atoms is 100% by mol, and
3 to 30 parts by mass of an ethylene α-olefin copolymer (C) comprising 50 to 99% by mol of a structural unit derived from ethylene and 1 to 50% by mol of a structural unit derived from an α-olefin having 3 to 20 carbon atoms, wherein the sum of the structural unit derived from ethylene and the structural unit derived from an α-olefin having 3 to 20 carbon atoms is 100% by mol,
wherein the sum of the component (A) and the component (B) is 100 parts by mass; and
a base layer.
2. The stretched laminated film according to claim 1 , wherein the propylene-based polymer (A) contains 80 to 100% by mass of a propylene-based polymer (a1) having a melting point (Tm) of not lower than 120° C. but lower than 150° C. measured by differential scanning calorimetry (DSC), and 0 to 20% by mass of a propylene-based polymer (a2) having a melting point (Tm) of not lower than 150° C. but not higher than 170° C. measured by the same method, wherein the sum of the component (a1) and the component (a2) is 100% by mass.
3. The stretched laminated film according to claim 1 , wherein the propylene-based polymer (A) contains 95 to 99% by mass of a propylene-based polymer (a1) having a melting point (Tm) of not lower than 120° C. but lower than 150° C. measured by differential scanning calorimetry (DSC), and 1 to 5% by mass of a propylene-based polymer (a2) having a melting point (Tm) of not lower than 150° C. but not higher than 170° C. measured by the same method, wherein the sum of the component (a1) and the component (a2) is 100% by mass.
4. The stretched laminated film according to claim 1 , wherein the 1-butene-based polymer (B) is a 1-butene-based polymer (B′) having a melting point (Tm) of lower than 120° C. measured by differential scanning calorimetry (DSC) and comprising 10 to 90% by mol of a structural unit derived from 1-butene and 10 to 90% by mol of a structural unit derived from propylene, wherein the sum of the structural unit derived from 1-butene and the structural unit derived from propylene is 100% by mol.
5. The stretched laminated film according to claim 4 , wherein the 1-butene-based polymer (B′) contains one or more 1-butene-based polymers selected from the group consisting of a 1-butene-based polymer (b1) having a melting point (Tm) of not lower than 90° C. but not higher than 110° C. measured by differential scanning calorimetry (DSC), a 1-butene-based polymer (b2) having a melting point (Tm) of not lower than 65° C. but lower than 90° C. measured by the same method and a 1-butene-based polymer (b3) having a melting point (Tm) of lower than 65° C. measured by the same method.
6. The stretched laminated film according to claim 5 , wherein the 1-butene-based polymer (B′) contains two or more 1-butene-based polymers selected from the group consisting of the 1-butene-based polymer (b1), the 1-butene-based polymer (b2) and the 1-butene-based polymer (b3).
7. The stretched laminated film according to claim 5 , wherein the 1-butene-based polymer (b1) and the 1-butene-based polymer (b2) are polymers produced by using a metallocene catalyst.
8. A packaging bag in which the peripheral parts of the stretched laminated film according to claim 1 are sealed while the heat-sealable layers are facing inside.
9. A package composed of the packaging bag according to claim 8 housing an item to be packaged.
10. A stretched laminated film having a heat-sealable layer composed of a resin composition which contains 50 to 97 parts by mass of a propylene-based polymer (A) having a melting point (Tm) of not lower than 120° C. but not higher than 170° C. measured by differential scanning calorimetry (DSC), and comprising more than 50% by mol of a structural unit derived from propylene, provided that the propylene-based polymer (A) contains 90 to 99% by mass of a propylene-based polymer (a1) having a melting point (Tm) of not lower than 120° C. but lower than 150° C. measured by differential scanning calorimetry (DSC), and 1 to 10% by mass of a propylene-based polymer (a2) having a melting point (Tm) of not lower than 150° C. but not higher than 170° C. measured by the same method, wherein the sum of the component (a1) and the component (a2) is 100% by mass, and
3 to 50 parts by mass of a 1-butene-based polymer (B) having a melting point (Tm) of lower than 120° C. measured by differential scanning calorimetry (DSC), and comprising 10 to 90% by mol of a structural unit derived from 1-butene and 10 to 90% by mol of a structural unit derived from an α-olefin having 3 or 5 to 20 carbon atoms, wherein the sum of the structural unit derived from 1-butene and the structural unit derived from an α-olefin having 3 or 5 to 20 carbon atoms is 100% by mol,
wherein the sum of the component (A) and the component (B) is 100 parts by mass; and
a base layer.
11. The stretched laminated film according to claim 10 , wherein the propylene-based polymer (A) contains 95 to 99% by mass of a propylene-based polymer (a1) having a melting point (Tm) of not lower than 120° C. but lower than 150° C. measured by differential scanning calorimetry (DSC), and 1 to 5% by mass of a propylene-based polymer (a2) having a melting point (Tm) of not lower than 150° C. but not higher than 170° C. measured by the same method, wherein the sum of the component (a1) and the component (a2) is 100% by mass.
12. The stretched laminated film according to claim 10 , wherein the 1-butene-based polymer (B) is a 1-butene-based polymer (B′) having a melting point (Tm) of lower than 120° C. measured by differential scanning calorimetry (DSC) and comprising 10 to 90% by mol of a structural unit derived from 1-butene and 10 to 90% by mol of a structural unit derived from propylene, wherein the sum of the structural unit derived from 1-butene and the structural unit derived from propylene is 100% by mol.
13. The stretched laminated film according to claim 12 , wherein the 1-butene-based polymer (B′) contains one or more 1-butene-based polymers selected from the group consisting of a 1-butene-based polymer (b1) having a melting point (Tm) of not lower than 90° C. but not higher than 110° C. measured by differential scanning calorimetry (DSC), a 1-butene-based polymer (b2) having a melting point (Tm) of not lower than 65° C. but lower than 90° C. measured by the same method and a 1-butene-based polymer (b3) having a melting point (Tm) of lower than 65° C. measured by the same method.
14. The stretched laminated film according to claim 13 , wherein the 1-butene-based polymer (B′) contains two or more 1-butene-based polymers selected from the group consisting of the 1-butene-based polymer (b1), the 1-butene-based polymer (b2) and the 1-butene-based polymer (b3).
15. The stretched laminated film according to claim 13 , wherein the 1-butene-based polymer (b1) and the 1-butene-based polymer (b2) are polymers produced by using a metallocene catalyst.
16. A packaging bag in which the peripheral parts of the stretched laminated film according to claim 10 are sealed while the heat-sealable layers are facing inside.
17. A package composed of the packaging bag according to claim 16 housing an item to be packaged.