Polyethylene Sealant Film Having High Strength and Package Using the Same

Patent metadata

Field	Value
Publication number	US-2017173928-A1
Application number	US-201615382608-A
Country	US
Kind code	A1
Filing date	Dec 17, 2016
Priority date	Dec 17, 2015
Publication date	Jun 22, 2017
Grant date	—

Abstract

In order to provide a polyethylene sealant film having great strength and good heat sealability, despite being thin, a multilayer polyethylene sealant film is produced by a method including coextruding and stretching a sealant layer formed of a low density polyethylene resin or linear low density polyethylene resin and an orientation layer including a polyethylene resin having a melting point higher than the sealant layer, by an inflation method at a temperature higher than the melting point of the sealant layer and higher than the Vicat softening temperature, but lower than the melting point of the orientation layer.

First claim

We claim:

1 . A method of producing a multilayer polyethylene sealant film, the method comprising:
coextruding and stretching a sealant layer comprising a low density polyethylene resin or linear low density polyethylene resin, and an orientation layer comprising a polyethylene resin having a melting point higher than the sealant layer, by an inflation method at a temperature higher than a melting point of the sealant layer and higher than a Vicat softening temperature, but lower than the melting point, of the orientation layer.

2 . A method of producing a multilayer polyethylene sealant film as set forth in claim 1 , wherein the polyethylene resin of the orientation layer is a low density polyethylene resin or linear low density polyethylene.

3 . A method of producing a multilayer polyethylene sealant film as set forth in claim 1 , wherein the low density polyethylene resin or linear low density polyethylene resin of the sealant layer has a melting point of 90-110° C. and a Vicat softening temperature of 70-105° C., and the polyethylene resin of the orientation layer has a melting point of 120-130° C. and a Vicat softening temperature of 80-120° C.

4 . A method of producing a multilayer polyethylene sealant film as set forth in claim 1 , wherein:
the low density polyethylene resin or linear low density polyethylene resin of the sealant layer has an MFR of 0.1-5 g/10 minutes; and the polyethylene resin of the orientation layer has an MFR of 0.1-5 g/10 minutes, a molecular weight distribution (Mw/Mn) of 6 or more, and a melt tension of 5-15 g.

5 . A method of producing a multilayer polyethylene sealant film as set forth in claim 1 , wherein a blow ratio of said inflation method is 2-3.5.

6 . A method of producing a multilayer polyethylene sealant film as set forth in claim 1 , wherein the orientation layer comprises an outer layer and an intermediate layer, wherein a melting point and a Vicat softening temperature of the polyethylene resin of the intermediate layer are lower than a melting point and a Vicat softening temperature of the polyethylene resin of the outer layer, respectively.

7 . A method of producing a multilayer polyethylene sealant film as set forth in claim 6 , wherein a part of the polyethylene resin forming the outer layer is a linear low density polyethylene having an MFR of 0.1-5 g/10 minutes provided with shearing heat history at 180° C. or more.

8 . A method of producing a multilayer polyethylene sealant film as set forth in claim 6 , wherein a part of the polyethylene resin constructing the outer layer is a polyethylene crosslinked by using an organic peroxide.

9 . A coextruded inflation multilayer polyethylene sealant film comprising:
a sealant layer made of a low density polyethylene resin or a linear low density polyethylene having a melting point of 90-110° C. and a Vicat softening temperature of 70-105° C.; and an orientation layer made of a polyethylene resin having a melting point of 120-130° C. and a Vicat softening temperature of 80-120° C.; wherein a melting point and a Vicat softening temperature of the sealant layer are lower than those of the orientation layer, respectively.

10 . A coextruded inflation multilayer polyethylene sealant film as set forth in claim 9 , wherein the polyethylene resin of the orientation layer is a low density polyethylene resin or a linear low density polyethylene resin.

11 . A coextruded inflation multilayer polyethylene sealant film as set forth in claim 9 , wherein the orientation layer has an orientation degree of 0.05-0.5.

12 . A coextruded inflation multilayer polyethylene sealant film as set forth in claim 9 , wherein:
the orientation layer comprises an outer layer and an intermediate layer; and a melting point and a Vicat softening temperature of the intermediate layer are lower than a melting point and a Vicat softening temperature of the outer layer, respectively.

13 . A package comprising:
a coextruded inflation multilayer polyethylene sealant film as set forth in claim 9 ; and a substrate film laminated to said sealant film.

14 . A package as set forth in claim 13 , further comprising:
a heat seal between the sealant layers of the coextruded inflation multilayer polyethylene sealant film, said heat seal having a strength of 12-20 N/15mm in width.

Assignees

• Hosokawa Yoko Kk

Inventors

• Kobayashi Yukio
• Kageyama Yohei
• Miyazaki Munenori
• Kojima Yoshihiro
• Tanaka Yoshikazu

Classifications

• B32B2307/558

  Impact strength, toughness · CPC title

• B32B2307/30

  having particular thermal properties · CPC title

• B32B2553/00

  Packaging equipment or accessories not otherwise provided for · CPC title

• B32B27/327

  comprising polyolefins obtained by a metallocene or single-site catalyst · CPC title

• B32B27/26

  using curing agents · CPC title