Polyolefin-based resin wrap film and wrap film-encasing body

Patent metadata

Field	Value
Publication number	US-10017616-B2
Application number	US-201415103061-A
Country	US
Kind code	B2
Filing date	Dec 15, 2014
Priority date	Dec 16, 2013
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

There is provided a polyolefin-based resin wrap film which contains a polyolefin-based resin, wherein the wrap film is torn in the machine direction when being torn in the machine direction; the wrap film is torn in the transverse direction when being torn in the transverse direction; the wrap film is torn either in the machine direction or in the transverse direction when being torn in a direction at 45° to the machine direction; an acute angle formed by a tearing direction and a cut line when the wrap film is torn in a direction at 45° to the machine direction is 30 to 60°; and a tear strength when the wrap film is torn in a direction at 45° to the machine direction is 10 g or lower.

First claim

The invention claimed is:

1. A polyolefin-based resin wrap film comprising a polyethylene-based resin,
wherein the wrap film is torn in a machine direction when being torn in the machine direction;
the wrap film is torn in a transverse direction when being torn in the transverse direction;
the wrap film is torn either in the machine direction or in the transverse direction when being torn in a direction at 45° to the machine direction;
an acute angle formed by a tearing direction and a cut line when the wrap film is torn in a direction at 45° to the machine direction is 30 to 60°;
a tear strength when the wrap film is torn in a direction at 45° to the machine direction is 10 g or lower; and
a machine-direction shrinkage factor (Smd) determined by the following formula (1) and a transverse-direction shrinkage factor (Std) determined by the following formula (2) satisfy Smd≥2.5, Std≥2.5, Smd×Std≥10, and Std/Smd=0.5 to 10:
machine-direction shrinkage factor ( Smd )=100/(100 −αmd )  (1); and

transverse-direction shrinkage factor ( Std )=100/(100−α td )  (2),

wherein in the above formulae (1) and (2), αmd represents a maximum thermal shrinkage (%) in the machine direction; and αtd represents a maximum thermal shrinkage (%) in the transverse direction.

2. The polyolefin-based resin wrap film according to claim 1 ,
wherein an elastic modulus thereof in the machine direction is 300 MPa or higher; and
a puncture strength thereof is 260 g or lower.

3. The polyolefin-based resin wrap film according to claim 1 , wherein in an azimuth distribution profile of a scattering intensity at a scattering angle of 2θ=20.9° to 21.8° when an X-ray beam of 0.154 nm in wavelength is allowed to be incident on the film from a film normal direction and transmission wide-angle X-ray scattering is measured,
the azimuth distribution profile has four scattering peaks;
adjacent scattering peak intervals of the four scattering peaks are 90°±10°;
an oriented component ratio R is 0.01 or higher and 100 or lower; and
an average area of the four scattering peaks is 1 or larger and 89 or smaller.

4. The polyolefin-based resin wrap film according to claim 1 , wherein a melting point thereof in differential scanning calorimetry is 80 to 123° C.

5. The polyolefin-based resin wrap film according to claim 1 , wherein a gel fraction thereof is 10 to 60% by mass.

6. The polyolefin-based resin wrap film according to claim 1 , wherein a heat-resistive temperature thereof is 130° C. or higher.

7. A roll obtained by winding a polyolefin-based resin wrap film according to any one of claims 1 , 2 , and 3 to 6 .

8. A wrap film-encasing body, having a roll obtained by winding a polyethylene-based resin wrap film according to claim 7 , and a container encasing the roll,
wherein the container has a cutting tool to cut the polyethylene-based resin wrap film.

9. The wrap film-encasing body according to claim 8 , wherein the cutting tool is a projection-like tool provided on a part of the container.

10. A wrap film-encasing body, having a roll obtained by winding a polyethylene-based resin wrap film according to claim 7 , and a container encasing the roll,
wherein the container has no cutting tool to cut the polyethylene-based resin wrap film.

11. A resin wrap film comprising polyethylene-based resin, wherein the resin wrap film:
a) when torn in the machine direction to form a cut line, the cut line has an acute angle of from 0° to 15° from the machine direction;
b) when torn in the transverse direction to form a cut line, the cut line has an acute angle of from 0° to 15° from the transverse direction;
c) when torn in a direction at 45° from the machine direction to form a cut line, the cut line has an acute angle of from 30° to 60° from the direction of tearing at 45° from the machine direction;
d) has a tear strength when the wrap film is torn in a direction at 45° to the machine direction is 10 g or lower;
e) has a machine-direction shrinkage factor (Smd) greater than or equal to 2.5 wherein the Smd is calculated from the percent maximum thermal shrinkage in the machine direction (αmd) from the following formula: Smd=100/(100−αmd);
f) has a transverse-direction shrinkage factor (Std) greater than or equal to 2.5 wherein the Std is calculated from the percent maximal thermal shrinkage in the transverse direction (αtd) from the following formula: Std=100/(100−αtd);
g) the Smd multiplied by the Std is greater than or equal to 10; and
h) the Std divided by the Smd is from 0.5 to 10.

12. The resin wrap film according to claim 11 , wherein an elastic modulus thereof
in the machine direction is 300 MPa or higher; and
a puncture strength thereof is 260 g or lower.

13. The resin wrap film according to claim 11 , wherein in an azimuth distribution profile of a scattering intensity at a scattering angle of 2θ=20.9° to 21.8° when an X-ray beam of 0.154 nm in wavelength is allowed to be incident on the film from a film normal direction and transmission wide-angle X-ray scattering is measured,
the azimuth distribution profile has four scattering peaks;
adjacent scattering peak intervals of the four scattering peaks are 90°±10°;
an oriented component ratio R is 0.01 or higher and 100 or lower; and
an average area of the four scattering peaks is 1 or larger and 89 or smaller.

14. The resin wrap film according to claim 11 , wherein a melting point thereof in differential scanning calorimetry is 80 to 123° C.

15. The resin wrap film according to claim 11 , wherein a gel fraction thereof is 10 to 60% by mass.

16. The resin wrap film according to claim 11 , wherein a heat-resistive temperature thereof is 130° C. or higher.

17. A roll obtained by winding a resin wrap film according to claim 11 .

18. A wrap film-encasing body, having a roll obtained by winding a polyethylene-based resin wrap film according to claim 17 , and a container encasing the roll,
wherein the container has a cutting tool to cut the polyethylene-based resin wrap film.

19. The wrap film-encasing body according to claim 18 , wherein the cutting tool is a projection-like tool provided on a part of the container.

20. A wrap film-encasing body, having a roll obtained by winding a polyethylene-based resin wrap film according to claim 17 , and a container encasing the roll,
wherein the container has no cutting tool to cut the polyethylene-based resin wrap film.

Assignees

• Asahi Chemical Ind

Inventors

• Ueda Aritaka
• Asada Yoshihiro

Classifications

• B65D83/0882

  and for cutting interconnected articles · CPC title

• B29C55/28

  of blown tubular films, e.g. by inflation {(extrusion moulding of tubular films B29C48/03)} · CPC title

• C08J2323/20

  having four to nine carbon atoms · CPC title

• C08J2323/08

  Copolymers of ethene (C08J2323/16 takes precedence) · CPC title

• B29K2023/00

  Use of polyalkenes {or derivatives thereof} as moulding material · CPC title