JPH0655710A - Laminated packaging material - Google Patents

Abstract

PURPOSE:To make it possible to tear off a packaging body for thermal autoclaving using a nylon film being excellent in impact resistance, easily, linearly and in all directions by hands, without providing an unpacking assist member additionally. CONSTITUTION:In regard to a packaging material for thermal autoclaving prepared by laminating a biaxially stretched polypropylene film 1, a nylon film 2 and a heat-sealing resin layer 3 sequentially, a biaxially stretched film constituted of aromatic polyamide and 6-nylon is used as the nylon film 2. Lamination is made, on the occasion, so that the direction of a stretching axis in which the tearing property of the biaxially stretched polypropylene film is inferior coincides with the stretching direction in which the tearing property of the nylon film is excellent. It is preferable, besides, that a gas barrier layer is provided further between the nylon film 2 and the biaxially stretched polypropylene film 1 or the heat-sealing resin layer 3. As for the gas barrier layer, a layer constituted of an aluminum leaf, polyvinylidene chloride or a silicon oxide can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated packaging material capable of hermetically storing foods, pharmaceuticals and the like. More particularly, the present invention relates to an easily tearable laminated packaging material that can be easily torn linearly in either the longitudinal or lateral directions by hand.

[0002]

2. Description of the Related Art Conventionally, flat bags and standing pouches have been widely used as packages for liquid foods such as orange juice and fine powders. However, such flat bags and standing pouches are manufactured. As a laminated packaging material for this purpose, a material containing a highly rigid nylon film is used in order to improve the impact resistance and the standing (self-standing) property of the package. The following layer structures of such materials are known: OPP / ONy / LLDPE; OPP / Al foil / ONy / LLDPE; or OPP / ONy / Al foil / LLDPE.

Here, ONy is a biaxially stretched 6- or 6,6-nylon film, LLDPE is a linear low density polyethylene, OPP is a biaxially stretched polypropylene film, and Al foil is aluminum. Shows foil.

However, when the conventional laminated packaging material having such a nylon film is heat-sealed with LLDPE inside, the packaging material is torn linearly by hand when the contents are taken out. The problem was that it was very difficult. For example, OPP / ON
When a package formed from a packaging material having a structure of y / LLDPE is torn in the lateral direction, at the tearing end of the package, the front side of the tearing is several mm from the linear direction.
However, there is a problem in that there is a deviation of 30 to 40 mm on the back side.

For this reason, scissors or a knife is used for opening, or a stretched polyethylene layer excellent in linear cutting property is further laminated so that it can be torn linearly by hand. ing. Alternatively, it has been proposed to provide an unsealing assisting member made of a stretched film in a tearing direction at a portion to be unsealed on the outer surface of the package, that is, a portion to be torn by hand (Japanese Patent Publication No. 53-12216).
Issue).

[0006]

However, if a stretched polyethylene layer is further formed between ONy and LLDPE in order to tear it linearly by hand without using scissors, the number of manufacturing steps is increased. However, there has been a problem that the manufacturing cost of the packaging material increases due to the increase of the number of products. Further, the provision of the unsealing auxiliary member not only increases the manufacturing cost of the package, but also impairs its aesthetic appearance.

The present invention is intended to solve the above-mentioned problems of the prior art, and in a laminated packaging material using a nylon film having excellent impact resistance, a stretched polyethylene layer having a good linear cut property and an unsealing property. It is an object of the present invention to easily and linearly tear in a vertical or horizontal direction by hand without further providing an auxiliary member.

[0008]

The inventors of the present invention have used a biaxially stretched film made of an aromatic polyamide and 6-nylon in place of the 6- or 6,6-nylon film, and are biaxially stretched. The inventors have found that the above object can be achieved by laminating the polypropylene film so that the specific drawing axis direction of the polypropylene and the specific drawing axis direction of the nylon film coincide with each other, and have completed the present invention.

That is, the present invention provides a laminated packaging material in which a biaxially stretched polypropylene film, a nylon film and a heat-sealable resin layer are sequentially laminated, and the nylon film is a biaxially composed of aromatic polyamide and 6-nylon. Provided is a laminated packaging material which is a stretched film and is laminated so that the stretch axis direction of the biaxially stretched polypropylene film, which is inferior in tearability, and the stretch direction in which the tearability of the nylon film is good are matched. To do.

The present invention will be described below in detail with reference to the drawings. Note that the same numbers in the drawings indicate the same or equivalent components.

FIG. 1 is a sectional view of the laminated packaging material of the present invention. As shown in the figure, the packaging material for pressurizing and heating of the present invention comprises a biaxially oriented polypropylene film 1, a nylon film 2 and a heat sealable resin layer 3.

In the present invention, the biaxially stretched polypropylene film 1 is the outermost layer in the package. This biaxially oriented polypropylene film 1 is usually
Stretching is performed about 5 times in the machine direction and about 10 times in the transverse direction, and has a property of easily tearing in the transverse direction.

As described above, the nylon film 2 in the present invention is a film composed of an aromatic polyamide and 6-nylon, and is preferably produced by kneading the aromatic polyamide and 6-nylon. Use a film. In this case, it is necessary to use a biaxially stretched film, which can improve the tearability (linear cutability). Also in the case of biaxial stretching, it is preferable to perform biaxial stretching by an extrusion tubular method that can impart uniform tearability in the width direction. In this case, it has the property of being easily torn in the vertical direction.

As described above, the biaxially oriented polypropylene film 1 and the nylon film 2 each have a direction in which they are easily torn. Therefore, in order to achieve the same tearability (linear cutability) in the longitudinal and transverse directions in a well-balanced manner, the biaxially stretched polypropylene film has a poor tearability in the stretched axial direction and the tearability of the nylon film. Laminate so that the good stretching direction matches.

The nylon film 2 composed of this aromatic polyamide and 6-nylon has a conventional 6- or 6,
Since it has about 50% higher rigidity than the 6-nylon film, a standing pouch with excellent uprightness (self-standing) can be realized.

Such an aromatic polyamide can be selected from various aromatic polyamides depending on the purpose of use. For example, a semi-aromatic polyamide obtained by polycondensing metaxylene diamine and adipic acid can be preferably used. The compounding ratio of the aromatic polyamide and the 6-nylon varies depending on the kind of the aromatic polyamide used and the like, but the tearability and the conventional 6- or 6,
10-90% by weight of aromatic polyamide, from the viewpoint of achieving both impact resistance equivalent to that of 6-nylon film,
It is preferably 40 to 60% by weight, and 6-nylon is 9
It is 0 to 10% by weight, preferably 60 to 40% by weight.

The thickness of the nylon film 2 can be appropriately determined according to the purpose of use.

The heat-sealable resin layer 3 can be made of the same material as that conventionally used as a sealant layer for packaging materials, such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer,
An ionomer or the like can be used. Moreover, the thickness of the heat-sealable resin layer 3 is not particularly limited and can be appropriately determined as necessary.

In the present invention, as shown in FIG. 2 (a) or (b), a nylon film 2, a biaxially oriented polypropylene film 1 or a heat-sealable resin layer 3 is used.
A gas barrier layer 4 may be provided between the two. As a result, oxygen and water vapor can be efficiently blocked, and the deterioration of the contents can be prevented. As a material for forming such a gas barrier layer 4, a material that has been conventionally used for imparting gas barrier properties to a packaging material can be used. For example, an aluminum foil,
Polyvinylidene chloride, silicon oxide and the like can be preferably used.

The layer thickness of the cass barrier layer is not particularly limited and can be appropriately determined according to the purpose of use.

The laminated packaging material of the present invention can be manufactured by a conventional method. For example, dry laminating method,
It can be manufactured by a non-solvent laminating method, an extrusion lamination method, a neel lamination method, a wet lamination method, a hot melt lamination method, or the like, or by laminating each layer by combining these methods. Among them, the dry laminating method, the non-solvent laminating method, the extrusion lamination method, and the nilam lamination method are preferable, and in this case, the urethane adhesive is 0.5 to 10 g / m ² (dry), preferably 1.0 to 5 g. When used in an amount of / m ² (dry), the tearability can be further improved. This is because the adhesive layer made of the urethane-based adhesive does not easily stretch, and thus it is easy to follow the tearing of the packaging material. Therefore, it is preferable to bond at least one of the layers with a urethane adhesive.

When silicon oxide is laminated as the gas barrier layer 4, it can be carried out by a general vacuum vapor deposition method, an ion plating method, a sputtering method, a plasma vapor deposition method, a CVD method or the like, but it is preferable. It is formed by the vacuum deposition method, which has a great cost advantage.

The laminated packaging material of the present invention thus obtained can be obtained in various forms by the same method as in the prior art.
For example, it can be processed into a standing pouch, a retort sterilization package, and the like.

[0024]

The laminated packaging material of the present invention has a biaxially stretched film composed of an aromatic polyamide and 6-nylon as a part of its layer structure, and a biaxially stretched polypropylene film having a poor tearability. Since the layers are laminated so that the direction of the nylon film and the direction of stretching of the nylon film, which has a good tearing property, coincide with each other, it is possible to easily tear linearly by hand in both the longitudinal direction and the lateral direction.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 A 20 μm thick biaxially oriented polypropylene film (trade name; OP-U1: manufactured by Shinto Cello Corporation) and a polyurethane adhesive (trade name; A515 / A-50: Takeda Pharmaceutical Co., Ltd.) were used. Co., Ltd.) at 3 g / m ² , and 6-nylon was added to the aromatic polyamide in which meta-xylenediamine and adipic acid were polycondensed on it, and biaxially stretched nylon with a thickness of 15 μm. Films (made by Idemitsu Petrochemical Co., Ltd.) were laminated. At this time, the biaxially stretched polypropylene film was laminated so that the stretching axial direction in which the tearability was inferior to the stretching direction in which the tearability of the nylon film was good were matched. Furthermore, with the same polyurethane adhesive,
40 μm thick low density polyethylene film (trade name;
TUX-FCD: manufactured by Shinto Cerro Shoji Co., Ltd.) was laminated by a dry lamination method to produce the laminated packaging material of the present invention.

When the obtained packaging material was torn by hand, the deviation from the linear direction was 0 to 3 on the front side of the tear.
Can be pressed within mm, and 0 to 5 m on the back side
It could be held down to m, and showed excellent tearability (straight cut property). Next, when a similar test was conducted by shifting the tearing direction by 90 °, similarly excellent tearability was exhibited.

Example 2 An aluminum foil having a thickness of 9 μm was laminated between the nylon film of the packaging material of Example 1 and the biaxially oriented polypropylene film by using the same adhesive as that used in Example 1. In the same manner as in Example 1, the laminated packaging material of the present invention was manufactured. This packaging material was tested in the same manner as in Example 1. As a result, it showed excellent tearability in both directions. Moreover, since it had an aluminum foil in the layer structure, it exhibited excellent gas, especially oxygen and water vapor barrier properties.

Example 3 An aluminum foil having a thickness of 9 μm was laminated between the nylon film of the packaging material of Example 1 and the low density polyethylene film using the same adhesive as used in Example 1, except that A laminated packaging material of the present invention was produced in the same manner as in Example 1. This packaging material was tested in the same manner as in Example 1. As a result, it showed excellent tearability in both directions. Moreover, since it had an aluminum foil in the layer structure, it exhibited excellent gas, especially oxygen and water vapor barrier properties.

Comparative Example 1 A packaging material for pressure heat sterilization was prepared by repeating Example 1 except that biaxially stretched 6-nylon (trade name; Emblem RT: Unitika Ltd.) having a thickness of 15 μm was used as the nylon film. Obtained. This packaging material was tested in the same manner as in Example 1. As a result, at the end of the tear, the deviation from the straight line direction is 0 on the front side of the tear.
It was possible to press within 3 mm, but a maximum deviation of 38 mm occurred on the back side. Further, when the tearing direction was shifted by 90 °, the deviation from the linear direction could be suppressed within 0 to 3 mm on the front side of the tearing, but on the back side, a deviation of as much as 38 mm occurred.

Comparative Example 2 Example 1 was repeated except that the biaxially stretched polypropylene film was laminated so that the biaxially stretched polypropylene film had good tearability and the nylon film had good tearability. By repeating the above, a laminated package was obtained. A similar test was conducted on this packaging material. As a result, at the end of the tear, the deviation from the linear direction could be suppressed within 0 to 3 mm on the front side of the tear, but on the back side, a maximum deviation of 38 mm occurred. Further, when the tearing direction was shifted by 90 °, the deviation from the linear direction could be suppressed within 0 to 3 mm on the front side of the tearing, but on the back side, a deviation of as much as 38 mm occurred.

[0032]

According to the present invention, a laminated packaging packaging material using a nylon film having excellent impact resistance has a property that it can be easily torn linearly by hand in all directions without providing an opening assisting member. I was able to give it.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a laminated packaging material of the present invention.

FIG. 2 is a cross-sectional view of another embodiment of the laminated packaging material of the present invention.

[Explanation of symbols]

 1 Biaxially oriented polypropylene film 2 Nylon film 3 Heat sealable resin layer 4 Gas barrier layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B65D 65/26 9028-3E // B29K 23:00 77:00 B29L 9:00 4F (72) Invention Kayoko Matsumoto 1-5-1 Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd.

Claims (4)

[Claims] 1. A laminated packaging material in which a biaxially oriented polypropylene film, a nylon film and a heat-sealable resin layer are sequentially laminated, wherein the nylon film is a biaxially oriented film composed of aromatic polyamide and 6-nylon. The laminated packaging material is characterized in that the biaxially stretched polypropylene film is laminated so that the stretch axis direction inferior in tearability and the stretch direction in which the nylon film has good tearability coincide with each other. 2. The laminated packaging material according to claim 1, further comprising a gas barrier layer provided between the nylon film and the biaxially oriented polypropylene film or the heat-sealable resin layer. 3. The laminated packaging material according to claim 2, wherein the gas barrier layer is made of aluminum foil, polyvinylidene chloride or silicon oxide. 4. The laminated packaging material according to claim 1, wherein at least one of the layers is adhered using a urethane adhesive.