JP3355712B2 - Packaging material for pressurized heat sterilization and package using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material for pressurized and heated sterilization which is used for sealing a processed food so that the processed food can be distributed at room temperature. More specifically, the present invention
The present invention relates to a packaging material for sterilization under pressure and heat which has easy tearability and can be linearly torn by hand. The present invention also relates to a package using the packaging material for pressurized heat sterilization.

[0002]

2. Description of the Related Art In modern times, hamburgers, curries,
Various processed foods such as rice are widely available. In order to distribute such processed food at ordinary temperature, generally, the processed food is sealed in advance in a package made of a heat-resistant material, and subjected to a pressure heat sterilization (retort sterilization) treatment.

Conventionally, as such packaging materials for retort sterilization, polyethylene terephthalate film (outer layer) / aluminum foil (gas barrier layer, light-shielding layer) / polypropylene film (heat sealability) Generally, a layer obtained by laminating each layer of a resin layer) with a heat-resistant urethane-based adhesive by a dry lamination method is used.

[0004] However, such a packaging material has insufficient impact resistance when retort sterilization conditions of high pressure and high temperature are selected or a large package is obtained in order to improve the sterilization efficiency. There has been a problem that the package is sometimes damaged, and in the case of a large package, the package is damaged during handling such as transportation.

Therefore, in order to improve the impact resistance,
BACKGROUND ART A biaxially stretched 6- or 6,6-nylon film is sandwiched between an aluminum foil and a polypropylene film.

However, in the case where a retort sterilization package is formed using a conventional packaging material for pressurization and heat sterilization having such a nylon film, when the contents are taken out, the package is torn linearly by hand. There was a problem that it was very difficult. For example, biaxially extended 6- or 6,6-
When a package formed from a packaging material having a configuration in which a nylon film and a low-density polyethylene film are laminated is torn in the lateral direction, a deviation of several mm from the linear direction occurs at the end of the tear on the near side of the tear. In addition, there is a problem that a shift of 30 to 40 mm occurs on the back side. To solve this problem, it is conceivable to use a uniaxially stretched nylon film in which the nylon film is stretched in the tearing direction instead of in the biaxially stretched state. Dimensional stability is low because of the different shrinkage ratios due to different shrinkage ratios, so that it cannot be used as a packaging material for retort sterilization.

[0007] Therefore, in order to allow the retort sterilizing package to tear linearly by hand while having a nylon film, the outer surface of the retort sterilizing package is to be opened at a portion to be opened, that is, a portion to be torn by hand. It has been proposed to provide an opening assisting member made of a film stretched in the tearing direction (Japanese Patent Publication No. 53-12216).

[0008]

However, when the opening assisting member is provided in this manner, there is a problem that the manufacturing cost of the package for sterilizing the retort increases, and there is also a problem that the aesthetic appearance is impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and includes a package for pressurized heat sterilization using a nylon film having excellent impact resistance, and further provided with an opening assisting member. At least, it aims to be able to tear straight by hand.

[0010]

SUMMARY OF THE INVENTION The present inventors have achieved the above-mentioned problem by using a biaxially stretched film of a polymer blend of an aromatic polyamide and 6-nylon instead of a 6- or 6,6-nylon film. It has been found that the above object can be achieved, and the present invention has been completed.

That is, the present invention relates to an easily tearable packaging material for sterilization under pressure and heat in which an outer layer, a nylon film and a heat-sealable resin layer are sequentially laminated, wherein the nylon film comprises 10 to 90% by weight of an aromatic polyamide. And 10
A biaxially stretched film consisting of 90% by weight of 6-nylon , and the adhesion between at least one of the layers is
Coated with a coating amount (dry) of 0.5 to 10 g / m ²
Provided is an easily tearable packaging material for sterilization under pressure and heat, which is performed with a urethane-based adhesive .

Hereinafter, the present invention will be described in detail with reference to the drawings. In the drawings, the same numbers indicate the same or equivalent components.

FIG. 1 is a cross-sectional view of a packaging material for pressurizing and heating according to the present invention. As shown in the figure, the packaging material for pressurization and heating of the present invention comprises an outer layer 1, a nylon film 2, and a heat-sealable resin layer 3.

In the present invention, the outer layer 1 is a layer which is located outside the nylon film 2 when the package is formed,
It is necessary to withstand retort sterilization conditions, and it is preferable to have more excellent printability. The outer layer 1 is preferably made of a flexible resin film such as polyethylene, polypropylene, polyester, or nylon, preferably a polyethylene terephthalate film or a biaxially stretched polypropylene film. Also,
The thickness of the outer layer 1 is not particularly limited, and can be appropriately selected according to the purpose of use.

In the present invention, as described above, the nylon film 2 is a film composed of an aromatic polyamide and 6-nylon, and is preferably produced by kneading an aromatic polyamide and 6-nylon. Use a film. In this case, it is necessary to use a biaxially stretched film. The biaxially stretched film is preferably a film that has been biaxially stretched by an extrusion tubular method capable of imparting a uniform tearing property in the width direction. Thereby, the tearing property (linear cutting property) can be improved.

Further, such a nylon film 2 is
Since it has about 50% higher rigidity than the conventional 6- or 6,6-nylon film, it is possible to realize a standing pouch having excellent standing (self-standing) properties.

The aromatic polyamide as a material for forming such a nylon film 2 can be selected from various aromatic polyamides according to the purpose of use and the like. For example, a semi-aromatic polyamide obtained by polycondensation of meta-xylene diamine and adipic acid can be preferably used. The compounding ratio of the aromatic polyamide and 6-nylon is different depending on the kind of the aromatic polyamide used, but the tearing property and the impact resistance are equivalent to those of the conventional 6- or 6,6-nylon film. In order to achieve both, the aromatic polyamide is 10 to 90% by weight, preferably 40 to 60% by weight, and 6-nylon is 90 to 10% by weight.
% 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 of a packaging material, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer,
An ionomer or the like can be used. In addition, the thickness of the heat-sealable resin layer 3 is not particularly limited, and can be appropriately determined as needed.

In the present invention, FIG.
As shown in (b), a gas barrier layer 4 is provided between the nylon film 2 and the outer layer 1 or the heat-sealable resin layer 3.
Is preferably provided. Thereby, oxygen and water vapor can be cut off efficiently, and deterioration of the contents can be prevented. As such a gas barrier layer 4, a material conventionally used for imparting gas barrier properties to a packaging material can be used. For example, an aluminum foil, a polyvinylidene chloride layer, or silicon monoxide is mainly used. The general formula SixOy (x = 1, 2, y
= 0, 1, 2, 3) can be used.

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

Among these, the silicon oxide thin film needs only a thickness of several hundred angstroms to achieve a desired gas barrier property, and therefore can be formed at a low running cost by a general vacuum deposition method or the like. There is an advantage that you can do it. Moreover, since it is light transmissive, there is an advantage that the contents of the packaging material can be seen through, and there is also an advantage that incineration residues such as aluminum foil do not remain even when incinerated. Therefore, in the present invention, it is preferable to use a silicon oxide thin film as the gas barrier layer 4. In this case, the silicon oxide thin film may be directly laminated on the nylon film 2 or the like by a vacuum deposition method or the like,
As shown in FIG. 2 (c), it is difficult to provide a composite film in which a silicon oxide thin film 4b is previously formed on a thermoplastic resin film 4a such as a polyethylene terephthalate film by a vacuum evaporation method as a gas barrier layer 4. Is preferred.

[0023] The packaging material for pressurized heat sterilization of the present invention can be produced according to a conventional method. For example, it can be manufactured by laminating respective layers by a dry lamination method, a non-solvent lamination method, an extrusion lamination method, a neem lamination method, a wet lamination method, a hot melt lamination method, or a combination of these methods. it can. Among them, a dry lamination method, a non-solvent lamination method, an extrusion lamination method, and a neem lamination method are preferable. In this case, 0.5 to 10 g of a urethane-based adhesive is used.
/ M ² (dry), preferably 1.0 to 5 g / m ² (dry), the tearability can be further improved. This is because the adhesive layer made of the urethane-based adhesive is difficult to stretch, so that it can easily follow the tear of the packaging material. Accordingly, it is preferable that at least one of the layers is bonded with a urethane-based adhesive.

The thus obtained packaging material for pressurized heat sterilization of the present invention can be processed into a package for pressurized heat sterilization by a method similar to the conventional method. For example, as shown in FIG. 3 (a), the heat-sealing resin layer 3 of the packaging material 10 for pressurized heat sterilization of the present invention is folded inside as shown by an arrow with the heat-sealable resin layer 3 inside. The other two edges 6a and 6b except for the opening 5 are heat-sealed. Alternatively, as shown in FIG. 4A, two sheets of the packaging material for pressurizing and heating 10a of the present invention are provided.
And 10b are overlapped with the heat-sealable resin layer 3 inside as shown by the arrow, and the other three edges 6a, 6b and 6c are removed except for the opening 5 as shown in FIG. Obtained by heat sealing. In addition, although not shown, it can be processed into a normal standing pouch.

[0025]

The packaging material for pressurized heat sterilization of the present invention has a biaxially stretched film composed of aromatic polyamide and 6-nylon in a part of its layer structure, so that it can be torn linearly by hand. Becomes

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments.

Example 1 A urethane-based adhesive (trade name: A515 / A-50: manufactured by Takeda Pharmaceutical Co., Ltd.) was applied on a biaxially stretched polyethylene terephthalate film (trade name; P60c: manufactured by Toray Industries, Inc.) having a thickness of 12 μm. ) Is applied at 3.5 g / m ² , and 6-nylon is added to an aromatic polyamide obtained by polycondensation of metaxylenediamine and adipic acid, and the resulting film is biaxially stretched and has a thickness of 15 μm. (Trade name: Uniathlon: manufactured by Idemitsu Petrochemical Co., Ltd.). Further, a 60 μm-thick polypropylene film (trade name: ZK-93K: manufactured by Toray Industries, Inc.) is laminated on the nylon film with the same urethane adhesive as described above by a dry lamination method, and the pressure of the present invention is reduced. A packaging material for heat sterilization was manufactured.

From the obtained packaging material, a package (130 × 170 mm, heat seal width 10) as shown in FIG.
mm).

In the obtained package, water: salad oil = 1: 1
And a retort sterilization test (heat resistance, pressure resistance, shrinkage, impact resistance) and a tear test (linear cutability test) were conducted at 120 ° C. for 30 minutes. Each test method and evaluation are as follows. Retort sterilization test (heat resistance) The case where the package is not damaged under the retort sterilization condition is represented by “○”, and the case where it occurs is represented by “x”; (pressure resistance) After the retort sterilization treatment, 50 kg static pressure is set to 1
Over a period of minutes, "O" indicates that the package is not damaged, and "X" indicates that the package is damaged. (Shrinkability) "Shrinkage rate of less than 1.0% in both the vertical and horizontal directions under retort sterilization conditions is" (Circle), 1.0% to 3.0% is represented by "、 ３", and 3.0% or more is represented by "x"; (impact resistance): After retort sterilization treatment, 1% at 23 ° C.
Drop vertically three times on flat concrete from a height of m, and mark "O" if the package does not break and "X" if it does. A notch is formed in the heat seal part of the tear test. Tear by hand, and the deviation from the linear direction is 5 mm on the near side and the back side of the tear.
Is less than “○”, 5 to 10 mm is “△”, 1
A case exceeding 0 mm is represented by “x”.

Table 1 shows the obtained test results. As is clear from Table 1, the packaging material and package for pressurized heat sterilization of the present invention had excellent retort sterilization properties and tear properties.

Example 2 Example 9 was repeated except that a 9 μm-thick aluminum foil was laminated between the nylon film and the polypropylene film of the packaging material of Example 1 using the same adhesive as that used in Example 1. In the same manner as in Example 1, a packaging material for pressurized heat sterilization of the present invention was produced. A package was manufactured from this packaging material in the same manner as in Example 1, and a similar test was performed. Table 1 shows the results.
Shown in As is clear from Table 1, the packaging material and package for pressurized heat sterilization of the present invention had excellent retort sterilization properties and tear properties. In addition, since the aluminum foil is included in the layer structure, excellent gas barrier properties, particularly, oxygen and water vapor barrier properties were exhibited.

Example 3 Example 9 was repeated except that a 9 μm-thick aluminum foil was laminated between the nylon film of the packaging material of Example 1 and polyethylene terephthalate using the same adhesive as that used in Example 1. In the same manner as in Example 1, a packaging material for pressurized heat sterilization of the present invention was produced. A package was manufactured from this packaging material in the same manner as in Example 1, and a similar test was performed. Table 1 shows the results. As is clear from Table 1, the packaging material and package for pressurized heat sterilization of the present invention had excellent retort sterilization properties and tear properties. In addition, since the aluminum foil is included in the layer structure, excellent gas barrier properties, particularly, oxygen and water vapor barrier properties were exhibited.

Example 4 A print layer was formed on a 12 μm-thick biaxially stretched polyethylene terephthalate film (trade name: P60c, manufactured by Toray Industries, Inc.) using a urethane-based ink, and a urethane-based adhesive was formed on the print layer. (Trade name; A515 / A-50: manufactured by Takeda Pharmaceutical Co., Ltd.) at 3.5 g / m ² .

On the coated surface, a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm (trade name: P60)
c: manufactured by Toray Industries, Inc.), a composite film in which a 1500 Å thick silicon oxide vapor-deposited film was formed on one surface was laminated with the polyethylene terephthalate film surface thereof superposed.

Further, a urethane-based adhesive (trade name: A515 / A-50: manufactured by Takeda Pharmaceutical Co., Ltd.) is applied at 3.5 g / m ² on the silicon oxide deposition surface, and metaxylenediamine is further applied thereon. 6-nylon is added to an aromatic polyamide obtained by polycondensation of adipic acid and adipic acid, and a 15 μm-thick nylon film stretched biaxially (trade name: Uniathlon:
Idemitsu Petrochemical Co., Ltd.), and a 80 μm-thick polypropylene film (trade name: ZK-93K: manufactured by Toray Industries, Inc.) is laminated by a dry lamination method using the same urethane-based adhesive. The packaging material for pressurized heat sterilization for the body was manufactured.

Apart from this, instead of the polyethylene terephthalate film on which the packaging material for pressurizing and heating sterilization for the above-mentioned standing pouch (body portion) is printed, the above-mentioned composite film (a silicon oxide vapor-deposited film is formed) is also used. Standing pouch (bottom part) in the same manner as described above, except that a laminated stretched polyethylene terephthalate film) is used and the silicon oxide deposited film is laminated on the inside.
Packaging material for pressurized heat sterilization was manufactured. A normal standing pouch (190 × 140 (bottom width: 40 mm)) was manufactured using the material thus obtained, and a retort sterilization test and a tear test were performed in the same manner as in Example 1. Table 1 shows the results.

As is clear from Table 1, this standing pouch exhibited excellent heat resistance, pressure resistance, shrinkage, impact resistance and tearing properties, similarly to the packages obtained in Examples 1 to 3. . In particular, regarding impact resistance, 4% acetic acid
Even if a high-load impact test was conducted, in which the sample was naturally dropped from a height of 1.6 m at room temperature or at 5 ° C. onto a flat concrete at room temperature or at 5 ° C., as shown in Table 2, retort sterilization (temperature of 120 ° C. or (125 ° C., sterilization time 20 minutes or 30 minutes), the number of drops before breaking the bag was 3 or more, and excellent impact resistance was exhibited.

Further, ten standing pouches of this example were prepared, and the oxygen permeation amount (ml / m ² · day · atm) under the conditions of 30 ° C. and 70% RH was measured. Table 2 shows the average value of the measurement results. As is clear from Table 2, before and after the retort sterilization (temperature of 120 ° C. or 125 ° C., sterilization time of 20 or 30 minutes), the oxygen permeation amount which can be said to be a practically sufficient oxygen barrier property for both the trunk and the bottom of the standing pouch. (4ml / m ²・ day ・ at
m), showing excellent oxygen barrier properties.

Comparative Example 1 A package for pressurized heat sterilization was obtained by repeating Example 1 except that a 6 μm-thick biaxially stretched 6-nylon (trade name: Unilon G101: manufactured by Idemitsu Petrochemical Co., Ltd.) was used as a nylon film. The material was obtained. A package was manufactured from this packaging material in the same manner as in Example 1, and a similar test was performed. The results are shown in Table 1. As is clear from Table 1, the packaging material and the package of this comparative example were inferior in tearability.

Comparative Example 2 Pressure sterilization by heating by repeating Example 2 except that a biaxially stretched film of 6-nylon having a thickness of 15 μm (trade name: Unilon G101: manufactured by Idemitsu Petrochemical Co., Ltd.) was used as the nylon film. Packaging material was obtained. A package was manufactured from this packaging material in the same manner as in Example 1, and a similar test was performed. The results are shown in Table 1. As is clear from Table 1, the packaging material and the package of this comparative example were inferior in tearability.

[0041]

[Table 1] Heat resistance Pressure resistance Shrinkage Impact resistance Tearability Example 1 ○ ○ ○ ○ ○ 2 ○ ○ ○ ○ ○ 3 ○ ○ ○ ○ ○ 4 ○ ○ ○ ○ ○ ○ Comparative example 1 ○ ○ ○ ○ × 2 ○ ○ ○ ○ ×

[0042]

[Table 2] Retort sterilization conditions (120 ° C., 30 minutes) (125 ° C., 20 minutes) Before retort After retort Before retort High load impact resistance (number of drops to bag break) Room temperature 7 10 7 5.3 5 ° C. 5 4 5 4 Oxygen permeation amount (ml / m ² · day · atm) Body 0.3 2.2 0.3 2.4 Bottom 0.0 0.1 0.0 0.2

[0043]

According to the present invention, a packaging material and a package for pressurized heat sterilization using a nylon film having excellent impact resistance can be linearly torn by hand without further providing an opening assisting member. Could be given.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a packaging material for pressurized heat sterilization of the present invention.

FIG. 2 is a sectional view of another embodiment of the packaging material for pressurized heat sterilization of the present invention.

FIG. 3 is an explanatory view of a method for producing a package for pressurized heat sterilization of the present invention.

FIG. 4 is an explanatory view of a manufacturing method of another embodiment of the package for pressurized heat sterilization of the present invention.

[Explanation of symbols]

 Reference Signs List 1 outer layer 2 nylon film 3 heat-sealing resin layer 4 gas barrier layer 4a thermoplastic resin film 4b silicon oxide thin film

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Junichi Uchida 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Hideki Kodaira 5-1-1, Taito, Taito-ku, Tokyo Toppan Printing JP-A-4-59244 (JP, A) JP-A-4-169231 (JP, A) JP-A-4-185322 (JP, A) JP-A-4-216050 (JP, A) A) JP-A-53-83892 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (5)

(57) [Claims] 1. An easy tear for pressurized heat sterilization in which an outer layer, a nylon film and a heat sealing resin layer are sequentially laminated.
The nylon film has a thickness of 10 to 90.
Wt% aromatic polyamide and 10-90 wt% 6-
A biaxially stretched film composed of nylon and each layer
The adhesion between at least one of the layers is between 0.5 and 10 g /
The coating amount of m ² (dry) at the coated urethane adhesive
Easy pulling for pressurized heat sterilization, which is performed in
Ripping packaging material. 2. The easily tearable packaging material for pressurized heat sterilization according to claim 1, further comprising a gas barrier layer between the nylon film and the outer layer or the heat-sealing resin layer. 3. The easy-to- use pressurized heat sterilizer according to claim 2, wherein the gas barrier layer is an aluminum foil, a polyvinylidene chloride layer, a silicon oxide thin film, or a composite film in which a silicon oxide thin film is formed on a thermoplastic resin film. Tearable packaging material. 4. The easy tearable packaging material for pressurizing and heating sterilization according to any one of the heat sealable resin layer of claim 1 to 3 consists of polypropylene film. 5. A package obtained by facing the heat-sealable resin layer of the easily tearable packaging material for pressurized and heated sterilization according to any one of claims 1 to 4 , and heat-sealing except for an opening. body.