JP2001001470A - Packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging material excellent in hand cutting properties and thrust resistance and having high rigidity. SOLUTION: A packaging material 1 is constituted by laminating a film A and a film B. The film A has at least a biaxially stretched plastic film layer and the film B has at least a substrate layer mainly comprising polypropylene and the biaxially stretched film layer comprising the heat seal layer laminated to one surface of the substrate layer and the heat seal layer of the film B is arranged so as to become the surface on the side opposite to the laminated surfaces of the film A and the film B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material, and more particularly, to a packaging material having excellent hand-cutting property and puncture resistance and high rigidity.

[0002]

2. Description of the Related Art Packaging materials are generally selected in accordance with desired functions such as aesthetics, preservability of contents, and protection. However, as a packaging method, a film-like material having heat sealing properties is generally used. 2. Description of the Related Art A method of molding a packaging material into a bag shape by heat sealing and sealing the package after storing the content is often used. Conventionally, as a film having heat sealing properties, a film obtained by laminating a biaxially stretched film of polypropylene, polyester, nylon, or the like as a base material and laminating an unstretched film of polypropylene or polyethylene as a heat seal layer on the base material, A heat-seal layer was formed on the material by co-extrusion, and a biaxially stretched film was used as a single layer.

The above-mentioned packaging method requires hand tearability (low tear strength) because the film is torn by hand at the time of opening. However, a film obtained by laminating an unstretched film as a heat seal layer on a substrate is a heat seal layer. Is soft, the hand-cutting property tends to be insufficient, and the puncture resistance may be low. The film in which the heat seal layer is formed by co-extrusion has good hand-cutting properties, but the film tends to have insufficient rigidity. Conventionally, there is also a problem that a heat seal layer is thin and a seal leak tends to occur at the time of sealing.

[0004] Further, when the contents are food or the like, a packaging material having a barrier property against oxygen or water vapor may be used in order to maintain the preservability of the contents. In general, a film obtained by laminating a non-stretched film as a heat seal layer on a biaxially stretched substrate and a material having a barrier property such as polyvinylidene chloride or a metal oxide film is laminated on the substrate.

[0005] In many cases, a packaging material is provided with a design property by printing or the like on its surface. In the case of a packaging material provided with the above-described barrier property, in addition to lack of hand-cutting property and piercing resistance, in particular, metal is used. In the case of an oxide film, the barrier layer may be damaged due to bending of the film in the printing step, and the barrier property may be reduced.

[0006]

SUMMARY OF THE INVENTION The present invention relates to
It is an object of the present invention to provide a packaging material having high stab resistance and rigidity, and a packaging material having a barrier property and capable of preventing damage to a barrier layer during printing.

[0007]

The present invention relates to a packaging material comprising a film A and a film B laminated by lamination, wherein the film A has at least a biaxially stretched plastic film layer, But at least
A base layer mainly composed of polypropylene, and a biaxially stretched film layer including a heat seal layer laminated on one surface of the base layer, the heat seal layer of the film B is a film A and a film B It is an object of the present invention to provide a packaging material arranged so as to be on the side opposite to the laminating side.

[0008] The thickness of the various films or layers constituting the packaging material of the present invention is not particularly limited.
Is replaced with a "sheet", the effect of the present invention is the same, so that the term "film" in this specification also includes "sheet".

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. FIG. 1 is a sectional view showing an example of the configuration of the packaging material of the present invention. The packaging material 1 includes a film A composed of a single layer of a biaxially stretched plastic film layer 2 and a film B. The film B is made of a substrate layer 3 made of polypropylene.
And heat-sealable layer 4 having heat-sealability, and is biaxially stretched. Film A and Film B
Is laminated by dry lamination to form the packaging material 1.

The material for forming the plastic film layer mainly constituting the film A is not particularly limited as long as it can be laminated with the film B. Polypropylene, polyester, nylon which is generally used as a base material of a packaging material And the like. In particular, polypropylene,
It is a material selected from polyester and nylon,
It is preferable from the viewpoint of the purpose of use as a packaging material and cost.

The method for producing the plastic film layer, that is, the plastic film, is not particularly limited, and a plastic film layer formed by a usual general film forming method such as extrusion using a T-die and biaxially stretched by a conventional method is used. be able to.

The thickness of the plastic film layer is not particularly limited, and is appropriately set within a range that does not impair the operation of the present invention.

The base layer of the film B is mainly made of polypropylene, and the method for forming the base layer is not particularly limited. That is, it may be co-extruded together with the heat seal layer as described later, or the substrate layer alone may be formed into a film by an ordinary general film forming method such as extrusion using a T-die. .

The thickness of the substrate layer is not particularly limited, and is appropriately set within a range that does not impair the operation of the present invention.

The material constituting the heat seal layer in the film B is not particularly limited, and is generally a mixture of polypropylene and polyethylene used for a heat seal layer formed by co-extrusion onto a substrate, and onto a substrate. An ionomer resin or an acrylic resin used for the heat seal layer formed by coating can be used.

The method of laminating the heat seal layer on the substrate layer is not particularly limited. For example, a method of co-extrusion and lamination with the substrate layer, a method of coating on a film-formed substrate layer, or a method of direct laminating. And the like.

The thickness of the heat seal layer is preferably 1 μm or more, more preferably 2 μm or more, and particularly preferably 5 μm or more. If the thickness of the heat seal layer is out of the above range, a seal leak tends to occur at the time of sealing, and particularly when packing in a pillow form, a seal leak tends to occur at the center of the end seal.

After laminating the substrate layer and the heat seal layer, the film B is subjected to biaxial stretching. For biaxial stretching, use film A
Can be carried out in the same manner as in the case of the plastic film layer.

The method of laminating the film A and the film B is not particularly limited as long as it is a laminating method. However, for the purpose of using the packaging material of the present invention, the heat seal layer of the film B is laminated with the laminated surface of the film A and the film B. Place so that it is the opposite side.

[0020] The packaging material of the present invention may have a barrier layer in order to maintain the preservability of the contents such as food. The barrier layer can be formed on either or both of the film A and the film B. The barrier layer may be a single layer or a multilayer of two or more layers. When the barrier layer has a multilayer structure or when a barrier layer is provided at a plurality of locations on the film A and the film B, the constituent materials and thicknesses may be different for each layer.

In the film A, the barrier layer may be formed on one or both surfaces of the plastic film layer. In film B,
When the heat seal layer is formed by co-extrusion onto the base material layer from the purpose of using the packaging material of the present invention, the surface of the base material layer on which the heat seal layer is not formed, that is, the lamination with the film A When the heat-sealing layer is formed on the substrate and the heat-sealing layer is separately laminated on the substrate layer, one or both of the surfaces of the substrate layer, that is, the lamination surface with the film A and / or the heat-sealing layer and the substrate It can be formed between layers. 2 to 5 show configuration examples of the packaging material of the present invention having a barrier layer.

The material forming the barrier layer is not particularly limited, and polyvinylidene chloride, polyvinyl alcohol,
Examples thereof include an ethylene vinyl alcohol copolymer and a metal oxide.

The method of laminating the barrier layer is not particularly limited, and can be appropriately selected according to the material of the barrier layer. For example,
For a resin such as polyvinylidene chloride, polyvinyl alcohol, and ethylene vinyl alcohol copolymer, a coating method or the like can be used, and for a metal oxide, a vapor deposition method or the like can be used.

The barrier layer preferably has an oxygen permeability.
(O_TwoTR) is 0.2 to 20 (cc / m ^Two・ 24hr)
And a water vapor transmission rate (WVTR) of 0.2 to 10 (g /
m^Two・ 24 hr). Oxygen permeability and water
When the vapor permeability is within the above range, food
It is possible to enhance the preservability of the contents.

The thickness of the barrier layer is not particularly limited.
What is necessary is just to set suitably according to the kind of the material which forms a barrier layer, arrangement | positioning of a barrier layer, desired oxygen permeability and water vapor permeability.

The packaging material of the present invention can be provided with a design property by printing or the like as required. The surface to be printed or the like can be formed on any one or both surfaces of the film A, and the film B has a heat seal layer on the base material layer for the purpose of using the packaging material of the present invention. When formed by co-extrusion, the heat seal layer is formed on the surface on which the heat seal layer is not formed (laminated surface with the film A). When the heat seal layer is separately laminated on the base material layer, And / or between the heat seal layer and the base material layer.

Each layer constituting the packaging material of the present invention may contain other components such as a plasticizer as long as the function of the present invention is not impaired.

The packaging material of the present invention may have other layers in addition to the above-mentioned layers, as long as the function of the present invention is not impaired.

The thicknesses of the films A and B constituting the packaging material of the present invention and the total thickness of the packaging material of the present invention are not particularly limited.

Hereinafter, the effects of the present invention will be described in more detail with reference to Test Examples and Examples. Test example Test Method (1) Puncture Resistance (Puncture Strength) For the packaging materials of Examples 1 to 5 and Comparative Examples 1 to 3, a diameter of 0.
A 5 mm round head-shaped member is moved at a speed of 50 perpendicular to the film surface.
It pressed at mm / min, and measured the maximum stress value when the round head-shaped member penetrated the packaging material. (2) Hand tearability (tear strength) JIS for packaging materials of Examples 1 to 5 and Comparative Examples 1 to 3
The tear strength was measured according to K7128. (3) Rigidity The packaging materials of Examples 1 to 5 and Comparative Examples 1 to 3 were used as a sample having a width of 15 mm, and a stress value required for elongating the sample by 1% in the length direction was measured. (4) Barrier property Oxygen permeability (O ₂ TR) Measured according to JIS K7126. [Unit: cc
/ M ² · 24 hr] Water vapor transmission rate (WVTR) Measured according to ASTM F1249. [unit:
g / m ² · 24hr]

2. Test Results Table 1 shows the results of the above tests (1) to (4).

[0032]

[Table 1]

[0033]

EXAMPLE 1 A biaxially stretched polypropylene film (thickness: 20 μm) was used as a film A, and a film B was provided with a heat seal layer made of a mixture of polyethylene and polypropylene on one surface of a base material layer made of polypropylene. Laminated by extrusion method, biaxially stretched film (thickness 25μ)
m), the film A is arranged such that one side of the film B does not have a heat seal layer on one side thereof,
Lamination by dry lamination method, total thickness 45μm
Was obtained as Example 1.

Example 2 A packaging material having a total thickness of 37 μm was obtained in the same manner as in Example 1 except that a biaxially stretched polyethylene terephthalate film (thickness: 12 μm) was used as the film A. .

Example 3 As a film B, a heat-seal layer made of a mixture of polyethylene and polypropylene was laminated on one surface of a base material layer made of polypropylene by co-extrusion, and did not have a heat-seal layer of a biaxially stretched film. A packaging material having a total thickness of 45 μm was obtained in the same manner as in Example 1 except that a film (thickness: 25 μm) in which a barrier layer made of polyvinylidene chloride was further laminated on one side by a coating method was used. did.

Example 4 Film A in which a barrier layer made of polyvinylidene chloride was laminated on one surface of a biaxially stretched polypropylene film as a film A by a coating method (thickness: 20 μm)
m), a film B having a heat-seal layer made of a mixture of polyethylene and polypropylene laminated on one side of a base material layer made of polypropylene by a co-extrusion method and having no heat-seal layer of a biaxially stretched film Film on which a barrier layer made of polyvinylidene chloride was further laminated by a coating method on the surface of
m), the film A was arranged so that the surface of the film B having no barrier layer was in contact with the surface of the film B having no heat seal layer, and the film was laminated by a dry lamination method to give a total thickness of 38 μm. Was obtained as Example 4.

Example 5 A film A was prepared in the same manner as in Example 4 except that a film obtained by laminating a barrier layer made of alumina on one surface of a biaxially stretched polyester film by a vapor deposition method (thickness: 12 μm) was used. Thus, a packaging material having a total thickness of 30 μm was obtained, and the result was set to Example 5.

Comparative Example 1 A biaxially stretched polypropylene film (20 μm thick)
m), a non-stretched polypropylene film (thickness: 30 μm) was laminated as a heat seal layer by a dry lamination method to obtain a packaging material having a total thickness of 50 μm.
And

Comparative Example 2 A barrier layer made of polyvinylidene chloride was laminated on one side of a biaxially stretched polypropylene film by a coating method, and a non-stretched polypropylene film was used as a heat seal layer on the side having no barrier layer ( (Thickness: 30 μm) was laminated by a dry lamination method to obtain a packaging material having a total thickness of 50 μm.

Comparative Example 3 A heat seal layer made of a mixture of polyethylene and polypropylene was laminated on one side of a base material layer made of polypropylene by a co-extrusion method, and biaxially stretched to give a total thickness of 25 μm.
m of the packaging material was obtained, and Comparative Example 3 was obtained.

[0041]

Since the packaging material of the present invention has the above-described structure, it has heat sealing properties, and is excellent in hand-cutting properties, piercing resistance and rigidity.

Further, a barrier property can be imparted by providing a barrier layer. However, since the film A and the film B have a two-layer structure, for example, a plurality of barrier layers are provided, Can be separate. Therefore, rigidity, finer control of physical properties such as oxygen and water vapor permeability, or when laminating or printing, when the barrier layer is likely to be damaged, by providing the barrier layer on the less affected film In addition, the barrier layer can be prevented from being damaged. For example, when a barrier layer made of a metal oxide is provided on the film A, if printing is performed on the film B, damage to the metal oxide layer (barrier layer) due to bending during printing can be prevented, and the barrier property is maintained. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of the configuration of a packaging material of the present invention.

FIG. 2 is a sectional view showing another example of the configuration of the packaging material of the present invention.

FIG. 3 is a sectional view showing another example of the configuration of the packaging material of the present invention.

FIG. 4 is a sectional view showing another example of the configuration of the packaging material of the present invention.

FIG. 5 is a sectional view showing another example of the configuration of the packaging material of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 packaging material 2 plastic film layer of film A 3 substrate layer of film B 4 heat seal layer of film B 5 barrier layer A film A B film B

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) JL12 JL12C YY00C YY00D

Claims (6)

[Claims] 1. A packaging material comprising a film A and a film B laminated by lamination, wherein the film A has at least a biaxially stretched plastic film layer, and the film B has at least a base material mainly composed of polypropylene. A biaxially stretched film layer composed of a material layer and a heat seal layer laminated on one surface of the base material layer, wherein the heat seal layer of the film B is opposite to the laminate surface of the film A and the film B A packaging material characterized by being arranged so as to have a surface. 2. The packaging material according to claim 1, wherein the plastic film layer of the film A is made of a material selected from polypropylene, polyester, and nylon. 3. The packaging material according to claim 1, wherein the film A and / or the film B has a barrier layer. 4. The method according to claim 1, wherein the barrier layer comprises polyvinylidene chloride.
The packaging material according to claim 3, wherein the packaging material is a single layer or two or more layers made of a material selected from polyvinyl alcohol, an ethylene vinyl alcohol copolymer, and a metal oxide. 5. The method according to claim 1, wherein the barrier layer has an oxygen permeability (O ₂ T).
R) is 0.2 to 20 (cc / m ² · 24 hr),
Water vapor permeability (WVTR) of 0.2 to 10 (g / m ² ·
The packaging material according to claim 3 or 4, wherein the length is 24 hours. 6. The packaging material according to claim 1, wherein the thickness of the heat seal layer of the film B is 1 μm or more.