Easy-to-tear, unstretched resin film and laminate film for packaging material using the same

Patent metadata

Field	Value
Publication number	US-11292908-B2
Application number	US-201716318896-A
Country	US
Kind code	B2
Filing date	Jul 14, 2017
Priority date	Jul 20, 2016
Publication date	Apr 5, 2022
Grant date	Apr 5, 2022

Abstract

This invention provides an easy-to-tear resin film. Such easy-to-tear resin film is an easy-to-tear, unstretched resin film composed of a blend of a polyethylene terephthalate-based resin with the second resin having a difference in SP value from the polyethylene terephthalate-based resin of 1.1 to 4.0 (cal/cm3)0.5. This invention also provides a laminate film 1B for a packaging material comprising the easy-to-tear, unstretched resin film 10 between the inner layer film 20 serving as a heat seal surface and the surface layer film 30 comprising an isophthalic acid-modified polyethylene terephthalate resin having a copolymerization ratio of isophthalic acid component of 0 mol % to 5 mol %.

First claim

The invention claimed is:

1. An easy-to-tear, unstretched resin film consisting of a blend of a polyethylene terephthalate-based resin and a second resin having a difference in solubility parameter (SP) value from the polyethylene terephthalate-based resin of 1.1 to 4.0 (cal/cm 3 ) 0.5 ,
wherein the second resin is a cycloolefin copolymer or polymethyl methacrylate;
wherein the second resin is dispersed in a particulate state in the polyethylene terephthalate-based resin and the average aspect ratio of the particles is 1 to 1.76;
wherein the film has a tear strength in the longitudinal direction of 0.25 N or lower and a tear strength in the transverse direction of 0.25 N or lower; and
wherein the tear strength in the longitudinal direction and the tear strength in the transverse direction are measured according to the Trouser method using a test rate of 200 mm/minute at a temperature of 25° C.;
wherein the polyethylene terephthalate-based resin is an isophthalic acid-modified polyethylene terephthalate resin having a copolymerization ratio of isophthalic acid component of 1 mol % to 5 mol %, based on the whole dicarboxylic acid component of the isophthalic acid-modified polyethylene terephthalate resin;
wherein in the blend, the proportion of the polyethylene terephthalate-based resin is 65% to 75% by weight and the proportion of the second resin is 35% to 25% by weight.

2. The easy-to-tear, unstretched resin film according to claim 1 , wherein the second resin has Tg that is higher than Tg of the polyethylene terephthalate-based resin by at least 25° C.

3. The easy-to-tear, unstretched resin film according to claim 1 , wherein the melt viscosity ratio of the second resin to the polyethylene terephthalate-based resin is 0.3 to 1.6 at 270° C. and a shear rate of 121.6 (1/second).

Assignees

• Toyo Seikan Group Holdings Ltd
• Toyo Seikan Kaisha Ltd

Inventors

• Kawamura Satoshi
• Tomita Jiro
• OHSAWA Takafumi
• Ohta Yoshihiro
• Hara Takuya

Classifications

• B32B2307/714

  Inert, i.e. inert to chemical degradation, corrosion · CPC title

• B32B27/36

  comprising polyesters · CPC title

• B32B27/308

  comprising acrylic (co)polymers · CPC title

• B32B27/302

  comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers · CPC title

• C08L33/20

  Homopolymers or copolymers of acrylonitrile (C08L55/02 takes precedence) · CPC title