JP2014184652A - Liquid packaging composite film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new liquid packaging composite film which transfers no odor to contents and is not bulky as waste.SOLUTION: There is provided a liquid packaging composite film which has an outermost layer composed of a polyethylene resin, an intermediate layer composed of a polyamide resin, and an innermost layer composed of an amorphous polyester-based resin, wherein the total film thickness is in the range of 60 to 200 μm and the intermediate layer composed of the polyamide resin has a thickness in the range of 10 to 40 μm.

Description

  The present invention mainly relates to a coextruded composite film having good aroma retention and gas barrier properties as a packaging material for packaging liquid beverages such as mineral water and juice.

  Conventionally, containers such as glass bottles and PET bottles are widely used for packaging liquid beverages. However, there is a problem that empty bottles and empty plastic bottles after drinking the beverage in the container are bulky as garbage.

  On the other hand, as a flexible packaging bag capable of improving the bulk of the container, a multilayer film made of a polyethylene resin as an outer layer, a polyamide resin as an intermediate layer, and a polyethylene resin as a heat seal layer is used.

  The filling of the contents uses a vertical pillow wrapping machine. In this case, the required quality of the heat seal layer is that the odor and components of the contents contact layer resin are not transferred to the contents during storage after filling. It is done.

  Conventionally, a polyethylene resin is generally used as the resin for the heat seal layer. However, although such a multilayer film is not bulky as dust, there is a problem that an odor originating from the resin of the innermost polyethylene resin layer is transferred to the contents. Especially with mineral water, there is a problem that the taste is slightly changed and the commercial value is lowered.

JP 2012-56607 A

  This invention is made | formed in view of the said situation, The solution subject is to provide the novel composite film for liquid packaging which an odor does not transfer to the content and is not bulky as garbage.

  As a result of intensive studies in view of the above problems, the present inventor has found that the above problems can be easily solved by a film having a specific configuration, and has completed the present invention.

  That is, the gist of the present invention is a coextruded composite film having an outermost layer made of polyethylene resin, an intermediate layer made of polyamide resin, and an innermost layer made of amorphous polyester resin, and the total film thickness is 60 to 200 μm. And the thickness of the intermediate layer made of the polyamide resin is in the range of 10 to 40 μm.

  ADVANTAGE OF THE INVENTION According to this invention, the novel film composite film for liquid packaging which an odor does not transfer to the content and is not bulky as garbage can be provided, and the industrial value of this invention is high.

  The polyethylene resin layer disposed on the outermost layer of the composite film includes a low density polyethylene (hereinafter referred to as LDPE), a linear low density polyethylene (hereinafter referred to as LLDPE), and an ethylene-vinyl acetate copolymer (hereinafter referred to as EVA). ), An ethylene-acrylic acid copolymer (hereinafter referred to as EAA), an ionomer resin, and the like, and LDPE and LLDPE are preferred in view of the low odor of the resin.

  Various polyamide resins such as polyamide 6, polyamide 6/66, polyamide 12 and polyamide 6/12 can be suitably used as the polyamide (hereinafter referred to as Ny) resin layer of the intermediate layer. Particularly considering flexibility, film-forming property and cost, polyamide 6/66 having a low density is preferable, and the thickness of the Ny resin layer is preferably in the range of 10 to 40% of the total thickness, more preferably from 15% to 30%. If it is less than 10%, the pinhole resistance and oxygen barrier property tend to be inferior, and if it exceeds 40%, a problem that the film becomes hard may occur.

  An example of the heat seal resin layer disposed in the innermost layer of the composite film is an amorphous polyester resin, but a polyethylene terephthalate glycol resin (PETG) is preferred in view of the low odor of the resin.

Example 1:
A composite film having the following layer structure was formed by a coextrusion molding method. The following items were evaluated about the obtained film.
Layer structure: LLDPE1 (36.0 μm) / Adhesive resin 1 (7.0 μm) / Ny (24.0 μm) / Adhesive resin 2 (7.0 μm) / PETG (46.0 μm)
LLDPE: LLDPE having a density of 0.930 or more.
PETG: PETG with a density of 1.27

Comparative Example 1:
Layer structure: LLDPE1 (36.0 μm) / adhesive resin 1 (7.0 μm) / Ny (24.0 μm) / adhesive resin 2 (7.0 μm) / LLDPE2 (46.0 μm)
LLDPE1: LLDPE with a density of 0.930
LLDPE2: LLDPE having a density of 0.918.

(Sensory evaluation test)
Using the film obtained above, four sides were heat-sealed to make a bag (width 150 mm × length 150 mm), and this bag was packed with mineral water in a commercially available plastic bottle. The pack product after storing it in a constant temperature and humidity chamber (60 ° C., humidity 95%) and the mineral water of the pack product after boiling for 70 minutes at 70 ° C. boil and storing in the refrigerator for 6 days has a strange odor. (Several number of monitors, 3-point preference method, evaluated by comparison with commercially available mineral water in plastic bottles before filling bag products, and the risk rate was 5% or less. ).

  The film of the present invention can be suitably used as a packaging material for packaging liquid drinks such as mineral water and juice.

Claims (6)

A co-extruded composite film having an outermost layer made of polyethylene resin, an intermediate layer made of polyamide resin, and an innermost layer made of amorphous polyester-based resin, wherein the total film thickness is in the range of 60 to 200 μm, from the polyamide resin The intermediate film has a thickness in the range of 10 to 40 μm. The liquid packaging film according to claim 1, wherein the amorphous polyester resin is a polyethylene terephthalate glycol resin. The composite film for liquid packaging according to claim 1 or 2, wherein the polyethylene resin is a linear low-density polyethylene having a density of 0.925 to 0.945. The composite film for liquid packaging according to any one of claims 1 to 3, wherein the outermost layer does not substantially contain a fatty acid amide organic lubricant. The composite film for liquid packaging according to any one of claims 1 to 4, wherein the polyamide resin is polyamide 6-66. The composite film for liquid packaging according to any one of claims 1 to 5, wherein the density of the amorphous polyester resin is 1.25 to 1.30.