JP3014550B2 - Manufacturing method of laminated packaging material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a laminated packaging material having a gas barrier property, in particular, a metal magnesium oxide layer, a silicon oxide layer, an aluminum oxide layer or the like as an oxygen and water vapor barrier layer. More specifically, the present invention provides a laminated packaging that does not cause a decrease in gas barrier properties even when extrusion-coated with a heat-sealable thermoplastic resin, and that is particularly excellent in oxygen barrier properties and water vapor barrier properties and that requires a desired thickness. The present invention relates to a method for manufacturing a material.

[0002]

2. Description of the Related Art Conventionally, a bag (pouch) -shaped container is generally used as a form of a package for food or medicine, and a laminated material having a plastic film as a base material is widely used.

[0003] By the way, laminated packaging materials are required to have various functions and performances depending on the contents to be packaged. Among them, gas barrier properties for preventing oxidative deterioration and drying of the contents, especially oxygen barrier properties are required. And water vapor barrier properties are often required. Lamination of an aluminum foil on a plastic film having such an oxygen barrier property and a water vapor barrier property is widely performed. There is a problem in that aluminum foil becomes a lump when incinerated after use and remains as a processed material. For this reason, recently, a thin film layer of various metal oxides including magnesium oxide which is easy to incinerate and has excellent transparency is laminated on a plastic film by a vacuum evaporation method or the like.

[0004] As a conventional method of manufacturing a laminated packaging material having such a metal oxide layer, a metal oxide layer is laminated on a base film such as a flexible polyester film by a vacuum deposition method, and an anchor treatment is performed if necessary. And then extruding and coating a heat-sealable thermoplastic resin such as polyethylene. Alternatively, there has been a dry lamination method in which a film in which a metal oxide is laminated and a heat-sealing film such as polyethylene or polypropylene are adhered with an adhesive.

[0005]

However, since the metal oxide formed as described above is generally a thin film that is easily cracked, a heat-sealing thermoplastic resin melted at a high temperature of 300 ° C. or more is used. Extrusion coating has a problem that cracks occur due to expansion of the metal oxide layer itself and shrinkage of the base film due to the heat, and as a result, oxygen barrier properties and water vapor barrier properties are reduced. In particular, this phenomenon was remarkable in an oxide layer such as magnesium and silicon. Further, in this case, it is required to have a desired thickness.

As described above, the present invention solves the conventional problems, and extrudes a heat-sealable thermoplastic resin onto a metal oxide layer so that neither oxygen barrier property nor water vapor barrier property is reduced. And a method for producing a laminated packaging material having a desired thickness.

[0007]

Means for Solving the Problems The present invention has been made in view of the above-mentioned problems, and the invention according to claim 1 comprises a base material, a metal oxide layer and a heat-sealable thermoplastic resin layer sequentially. In the manufacturing method of the laminated laminated packaging material, while extruding by extrusion coating method while spraying a gas containing ozone on the surface to be in contact with the metal oxide layer of the heat-sealable thermoplastic resin that has been hot-melted in a curtain shape, This is a method for producing a laminated packaging material, wherein the laminate is laminated by laminating another heat sealable resin.

According to a second aspect of the present invention, based on the first aspect, the metal oxide is any one selected from a magnesium oxide layer, a silicon oxide layer, and an aluminum oxide layer. It is a method of manufacturing a material.

A third aspect of the present invention is based on the premise of the first and second aspects, wherein the heat-sealable thermoplastic resin is polyethylene and the extrusion temperature is 290 ° C. or less. It is a manufacturing method.

[0010]

[0011]

According to the method for producing a laminated material of the present invention, it is possible to activate the resin surface by spraying a gas containing ozone in a molten state on the heat-sealable thermoplastic resin layer. The extrusion temperature can be lowered by about 20 to 30 degrees, and the amount of heat of the molten resin at the time of extrusion coating received by the metal oxide layer is reduced to such an extent that the oxygen barrier property and the water vapor barrier property of the metal oxide layer are not impaired. And a desired thickness can be obtained.

Hereinafter, the present invention will be described in detail with reference to the drawings in which lamination of another heat sealable resin is not described.

FIG. 1 is an explanatory view of the production process of the laminated packaging material of the present invention.

First, the base material 1 is used as a base material of the laminated packaging material.
(Base film) (FIG. 1A) is prepared. As the base material 1, a biaxially stretched flexible resin film such as polyethylene, polypropylene, polyester, or nylon, preferably a polyethylene terephthalate film can be used. The thickness of the substrate 1 is not particularly limited, but is 6 to 100 μm, preferably 12 to 25 μm.
μm.

A metal oxide layer is formed on the substrate 1 by a conventional method in order to impart a gas, in particular, an oxygen barrier property and a water vapor barrier property to the laminated packaging material (FIG. 1B). For example, preferably by a vacuum evaporation method, an ion plating method, a sputtering method, or a plasma CVD method,
It can be formed by a vacuum vapor deposition method which has a great cost advantage.

The metal oxide layer 2 in the present invention can be made of at least one selected from oxides such as magnesium, aluminum, tin, titanium, zinc and zirconium and silicon oxides. Fluoride or the like may be contained as an impurity.

The thickness of the metal oxide layer 2 is 100 to 2000 angstroms, depending on the material used.
When flexibility is important, the thickness is about 200 to 800 angstroms.

Next, an anchor coat layer is formed on the metal oxide layer 2 by a conventional method (FIG. 1C). This is provided as needed in order to improve the adhesion of the heat-sealable thermoplastic resin. The anchor coat layer is a gravure version of a commonly used anchor coat agent such as urethane, polybutadiene, or polyethyleneimine.
It can be formed by coating and drying on the metal oxide layer 2 using a coater such as a Bose plate. Prior to the formation of the anchor coat layer 3, the metal oxide layer 2
A printing layer may be provided using an ink commonly used for packaging materials.

Subsequently, a heat-sealing thermoplastic resin 4 is formed on the anchor coat layer 3 by extrusion coating to produce a laminated packaging material (FIG. 1).
(D)). In this case, for example, 2
A gas such as air containing ozone is blown onto the surface of the thermoplastic resin melt-extruded at a low temperature of 90 ° C. or less, which is to be in contact with the metal oxide layer of the heat-sealable thermoplastic resin which is hot-melted into a curtain shape. Continuous while activating the surface 13
While extruding to ３０30 μm, another heat-sealable resin is laminated by laminating for coating.

As described above, in order to achieve desired heat sealing properties and film strength, heat sealing thermoplastic resin 4 is used.
In order to increase the thickness of the extrusion coating,
A heat-sealable thermoplastic resin 4 having a desired thickness is formed by preparing a resin film of an insufficient thickness and extruding the heat-sealable thermoplastic resin between the resin film and the metal oxide layer 2. In addition, extrusion coating is performed twice or more to obtain a desired thickness. If the thickness is to be greater than, for example, 30 μm, a resin film of an insufficient thickness is prepared at the time of extrusion coating, and a heat-sealable thermoplastic resin is extruded between the resin film and the metal oxide layer 2.

As such a heat-sealable thermoplastic resin, those similar to those conventionally used, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer and the like can be used.

The temperature of the melt extrusion from the T-die needs to be low enough not to impair the oxygen barrier property and the water vapor barrier property of the metal oxide layer, and the conditions differ depending on the resin. In this case, 270
Low temperature of ~ 290 degrees.

The ozone treatment conditions of the present invention are as follows: 10 to 40 g / Nm ³ of ozone generated by a known method is used, using a gas such as air as a carrier, and 1 to 10 Nm ³ / hr.
Is sprayed onto the above-mentioned molten thermoplastic resin. Actually, a value obtained by dividing the product of the ozone concentration and the flow rate of the carrier by the product of the line speed and the substrate width can be quantitatively managed as the ozone amount g / m ² .

The carrier gas in the present invention is not particularly limited, but air that can be used inexpensively and in large quantities, such as general ones such as argon and nitrogen, can be used.

Further, since ozone decomposes at about 60 to 70 ° C., it is preferable to control the temperature of the carrier gas as required.

The method of generating ozone may be a known one.
For example, it can be easily generated by air discharge treatment in a closed container, and can be transported quantitatively by a carrier gas.

The method of spraying the ozone-containing carrier gas is not particularly limited, but can be achieved by directly spraying the molten resin from a pipe having a plurality of small holes or a slit-shaped pipe-shaped blowing jig.

As described above, the position of the spraying jig 5 is such that the heat-sealable thermoplastic resin melt-extruded from the T-die 6 reaches the cooling roll 9 as close to the resin as possible while efficiently spraying the resin. It is desirable.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to a reference example as a basis for the embodiments. In addition, the following reference example does not describe a portion in which a resin film of a sufficient thickness is prepared at the time of extrusion coating and a heat-sealable thermoplastic resin is extruded between the resin film and the metal oxide layer 2. But,
In fact, they are essential requirements of the present invention.

REFERENCE EXAMPLE 1 A 600 Å thick magnesium oxide layer was formed on a 550 mm wide polyethylene terephthalate film 12 μm as a base material by a vacuum evaporation method, and an oil-based ink (LP Super (white)) was formed on the magnesium oxide layer. , Manufactured by Toyo Ink Manufacturing Co., Ltd.)
Was used to make a dry thickness of 2-3 μm (line speed 90 m / min, line tension 7K).
g, drying temperature 60 ° C).

After a polybutadiene-based anchor coating agent (EL451, manufactured by Toyo Ink Mfg. Co., Ltd.) was applied on the printing layer, a low-density polyethylene (density: 0.9) was coated thereon.
17MFR 7.2g / 10min) at T die temperature 2
It was melt-extruded at 80 ° C., extruded and coated to a thickness of 15 μm with ozone treatment under the following processing conditions to obtain a laminated packaging material.

Processing conditions Line speed 100 m / min Air gap 110 mm Ozone concentration 30 g / Nm ³ Carrier flow rate 3 Nm ³ / hr Ozone amount 2.7 * 10 ^-2 g / m ²

The moisture permeability (WVTR, g / m ² · day) of the printed solid portion and the uncoated portion of the laminate was measured at 40 ° C. under atmospheric pressure.
Under the condition of -90% RH, a moisture permeability tester (PERMA)
TRAN-W TWIN, MODERN CONTROL
LS, Inc.). Oxygen permeability (O ² T
R, cc / m ² · day), OXTRAN1
0 / 50A (MODERN CONTROLS, INC
Was measured at 25 ° C. and 100% RH under atmospheric pressure. Furthermore, the lamination strength of each of the printing solid portion and the uncoated portion was measured, and the adhesion was evaluated. Table 1 shows the results.

As is clear from Table 1, the laminate of this reference example showed lower values of moisture permeability and oxygen permeability than those obtained by extrusion coating at 310 ° C., which will be described later, and also had sufficient lamination strength.

Comparative Reference Example 1 A laminated material was produced in the same manner as in Reference Example 1 except that extrusion coating was performed at an extrusion temperature of 310 ° C., and moisture permeability and oxygen permeability were measured. Table 1 shows the results. As is clear from Table 1, the oxygen barrier property and the water vapor barrier property of the laminated packaging material of this comparative reference example are significantly reduced.

Comparative Reference Example 2 A laminated material was produced in the same manner as in Reference Example 1 except that extrusion coating was performed at an extrusion temperature of 270 ° C., and moisture permeability and oxygen permeability were measured. Table 1 shows the results. As is clear from Table 1, the laminate packaging material of this comparative reference example shows low values of the oxygen barrier property and the water vapor barrier property as in Reference Example 1, but the lamination strength is insufficient.

Reference Example 2 A laminated material was produced in the same manner as in Reference Example 1 except that extrusion coating was performed at an extrusion temperature of 290 ° C., and the moisture permeability and oxygen permeability were measured. Table 1 shows the results. As is apparent from Table 1, the laminated packaging material of Reference Example 2 showed good results in both the oxygen barrier property and the water vapor barrier property.

Reference Example 3 Under the same conditions as in Reference Example 1, the thickness of the polyethylene was set to 30 μm. Table 1 shows the results. As is clear from Table 1, both the oxygen barrier property and the water vapor barrier property showed good results.

Reference Example 4 A silicon oxide layer having a thickness of 650 angstroms was formed on a polyethylene terephthalate film 12 μm in the same manner as in Reference Example 1 by vacuum evaporation.
Hereinafter, evaluation was performed under the same conditions as in Reference Example 1. As is clear from Table 1, the laminate of this reference example exhibited lower values of moisture permeability and oxygen permeability than those obtained by extrusion coating at 310 ° C., which will be described later, and the laminate strength was sufficient.

[Comparative Reference Example 3] In Reference Example 4, the extrusion temperature was 310 ° C. As can be seen from Table 1, the oxygen barrier property and the water vapor barrier property of the laminated packaging material of this comparative reference example are significantly reduced.

Reference Example 5 Evaluation was made in the same manner as in Reference Example 1, except that 300 Å of aluminum oxide was used for the metal oxide layer.

Comparative Example 4 In Example 5, the extrusion was performed at 310 ° C.

[0043]

[Table 1]

[0044]

According to the present invention, while laminating another heat-sealable resin while laminating another heat-sealable resin while extruding a heat-sealable thermoplastic resin into the metal oxide layer while performing ozone treatment, the conventional method is used. It can be extruded at a low temperature of 20 to 30 degrees, and while maintaining the adhesiveness between the metal oxide and the resin, reduces the heat-induced deterioration to the metal oxide layer, and at the time of extrusion coating, does not provide sufficient thickness. Resin film can be formed. As a result, a practical laminated packaging material having a desired thickness without a decrease in oxygen barrier properties and water vapor barrier properties can be manufactured.

[0045]

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a laminated packaging material.

FIG. 2 is an explanatory diagram showing an ozone treatment step.

[Explanation of symbols]

 Reference Signs List 1 base material 2 metal oxide layer 3 anchor coat layer 4 heat-sealable thermoplastic resin layer 5 ozone blowing jig 6 T die 7 back roll 9 cooling roll 10 laminated film 11 laminated film

 ──────────────────────────────────────────────────続 き Continuing from the front page Judge Masami Kobayashi Judge Katsuhiko Ishii Judge Reiko Imamura (56) References JP-A-49-50081 (JP, A) JP-A-60-90751 (JP, A) JP-A-57-102318 (JP, A) JP-A-5-77382 (JP, A) JP-A-5-193018 (JP, A) JP-A-3-293129 (JP, A)

Claims (3)

(57) [Claims] In a method for producing a laminated packaging material in which a base material, a metal oxide layer and a heat-sealable thermoplastic resin layer are sequentially laminated, a metal oxide of the heat-sealable thermoplastic resin melted in a curtain shape is provided. A method for producing a laminated packaging material, comprising laminating by laminating another heat sealable resin while extruding by an extrusion coating method while spraying a gas containing ozone onto a surface to be in contact with a material layer. 2. The method according to claim 1, wherein the metal oxide is one selected from a magnesium oxide layer, a silicon oxide layer, and an aluminum oxide layer. 3. The method according to claim 1, wherein the heat-sealable thermoplastic resin is polyethylene and the extrusion temperature is 290 ° C. or less.