JPH08207196A - Packing material for heating sterilization - Google Patents

Abstract

PURPOSE: To provide a packing material for heating sterilization having various necessary capacities, not transferring an offensive smell component of a laminating adhesive for a film to content even when heating sterilization or pressure heating sterilization treatment is applied and not damaging taste of food being content. CONSTITUTION: For example, in a packing material obtained by successively laminating a surface layer 1, an adhesive layer 6a, an intermediate layer 2-1, an adhesive layer 6b and the innermost layer 5 from the outside, as the innermost layer 5, a non-oriented polypropylene resin layer 4 having a membrane layer 3 composed of inorg. matter provided to one surface thereof is used and this resin layer is laminated so that the membrane layer 3 thereof is turned to an adhesive surface.

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 for heat sterilization which can be suitably used for packaging foods, beverages, chemicals and the like and subjecting it to heat sterilization treatment.

[0002]

2. Description of the Related Art Conventionally, packaging materials for foods, beverages, medicines, etc., such as pouches, etc., have been subjected to heat sterilization or pressure heat sterilization treatment after the contents have been filled. In addition to various strengths and heat sealability, performance such as heat resistance and high gas barrier property is required.

A packaging material satisfying such requirements, that is,
Examples of the constitution of the multilayer film for heat sterilization pouches include, for example, biaxially stretched polyethylene terephthalate film (hereinafter PET film) / aluminum foil (hereinafter AL foil) / unstretched polypropylene film (hereinafter CPP film), PET in order from the outside. Film / AL foil / Biaxially stretched nylon film (hereinafter ON film) / C
PP film, PET film / ON film / CP
A structure such as a P film is common.

As the innermost layer (sealant layer) of the above-mentioned multi-layer film, non-oriented polypropylene excellent in heat sealability and heat resistance, for example, CPP film is used, and especially when cold impact resistance is also required, ethylene is used. -A propylene block copolymer film or the like is preferably used. In addition, a dry laminating method using a polyurethane-based adhesive made of a polyol or polyester and isocyanate is widely used for adhesion between the layers.

[0005]

However, even if a pouch is prepared by using the above-mentioned laminated film and the contents are filled and hermetically sealed, it is subjected to heat sterilization or pressure heat sterilization treatment. When applied, there was a problem that the odorous components of the adhesive and the like penetrated the innermost CPP layer and transferred to the contents, impairing the flavor of the contents, that is, the food.

The present invention has been made in view of the above problems, and is required for a usual packaging material for pressure heat sterilization in a multilayer film used as a packaging material for foods, beverages, chemicals and the like. In addition to having good performance, even when subjected to heat sterilization or pressure heat sterilization, there is no migration to the contents such as odorous components due to the adhesive, etc., and the flavor of the food such as contents is impaired. It is an object of the present invention to provide a packaging material for heat sterilization.

[0007]

In order to achieve the above object, as a result of earnest research, the following object of the present invention has been achieved. That is, the present invention, in the packaging material for heat sterilization in which a plurality of layers are laminated, the innermost layer is an innermost layer made of a non-oriented polypropylene resin, and an inorganic material or an organic material on the outer surface of the innermost layer. And a thin film layer of an inorganic substance contained therein, which is a packaging material for heat sterilization. In the above, the plurality of layers are generally roughly classified into a surface layer (outer layer) and a sealant layer (innermost layer), or a surface layer, an intermediate layer, and a sealant layer (innermost layer), each of which is May be a single layer,
Further, it may be composed of a plurality of layers.

As the surface layer, the conventionally known film used as the surface layer of the multilayer film for heat sterilization pouches in the present invention can be used as it is without any particular limitation. Usually, a PET film having excellent heat resistance and mechanical strength as well as printability, a biaxially oriented polypropylene film (hereinafter referred to as OPP film), and the like can be preferably used in the present invention. The thickness of the surface layer cannot be uniformly determined because it depends on the material of the film used and the weight of the contents to be packed.
In the case of T film, the range of 12 to 25 μm is preferable. When the thickness is less than 12 μm, the strength of the film is insufficient, and stable printing and lamination may not be performed, which is not preferable. On the other hand, when it exceeds 25 μm, not only the cost becomes high, but also the film becomes hard and the handling property is deteriorated, which is not preferable. In the case of an OPP film, a thickness of 20 μm to 30 μm is suitable.

The intermediate layer is provided as necessary in order to satisfy required performances such as imparting light shielding property, gas barrier property and improving mechanical strength. For example,
When light shielding and gas barrier properties are required, AL foil, aluminum-zinc alloy foil, and other metal foils are used. When transparency and gas barrier properties are required, ethylene / vinyl acetate copolymer Ken is used. Compound film,
To improve the mechanical strength, an ON film can be appropriately selected and used. Each of these may be used alone, or if necessary,
For example, a plurality of materials such as AL foil and ON film may be laminated and used. The intermediate layer is also not particularly limited in the present invention, and conventionally known materials used as an intermediate layer such as a packaging material for pressure heat sterilization can be used as they are.

The thickness of the intermediate layer also differs depending on the material of the selected film and the like, and the required performance such as mechanical strength and gas barrier property. For example O
In the case of N film, the range of about 10 μm to 30 μm is preferable. If the thickness is less than 10 μm, the mechanical strength is not always sufficient, and if the thickness exceeds 30 μm, there are few cases requiring higher mechanical strength for ordinary applications, which is rather expensive, which is not preferable. .
The thickness of AL foil is preferably about 7 to 30 μm, and the thickness of saponified ethylene / vinyl acetate copolymer film is preferably about 15 to 30 μm.

Next, regarding the innermost sealant layer, the packaging material for heat sterilization of the present invention is characterized by this sealant layer, and this layer is referred to as "inorganic substance or inorganic substance containing organic substance". It is composed of a non-oriented polypropylene resin layer having a thin film layer ". That is, the inorganic barrier on the outer surface of the layer of non-oriented polypropylene resin that has been conventionally used for the sealant layer, or, to provide a gas barrier property by providing a thin film layer of an inorganic substance containing an organic substance by such means as vapor deposition, the gas The barrier property is used to prevent the odorous components of the adhesive used in dry lamination from migrating to the contents through the sealant layer.

In the above-mentioned "layer of non-oriented polypropylene-based resin having a thin film layer of inorganic material or inorganic material containing organic material", the non-oriented polypropylene-based resin layer may be, for example, a block of polypropylene or ethylene-propylene. Non-stretched films such as copolymers, copolymers of propylene and other α-olefins, blend resins of polypropylene and other polymers such as polyethylene can be used. Then, these are used as a base film, and a thin film layer of an inorganic substance or an inorganic substance containing an organic substance is provided on one surface thereof. Thin layer of inorganic material, for example, silicon oxide (Si O _X), aluminum (Al), alumina (Al ₂ O _3), magnesium oxide (Mg O), tin oxide (Sn O ₂₎ is a thin film layer, such as, These are vacuum vapor deposition, sputtering, chemical vapor deposition (CVD
Method) and the like. Further, as the inorganic thin film layer containing an organic substance,
For example, there is a thin film layer of silicon oxide (Si O _x ) containing a mixture or compound of one or more elements among carbon, hydrogen, silicon and oxygen, which is, for example, 1,1,3 , 3-tetramethyldisiloxane, hexamethyldisiloxane and other organosilicon compounds are vaporized,
A raw material gas obtained by mixing oxygen gas and helium and / or argon, which are inert gases, into this is introduced into a plasma chemical vapor deposition machine in which a base material film is installed, and 60 to 500 is supplied.
It can be formed by vapor deposition to a thickness of Å.

In the sealant layer having this structure, the thin film layer made of an inorganic material or the like has a function of preventing the transfer of odorous components to the contents as described above, and the polypropylene resin layer has a function as a sealant. Therefore, when the intermediate layer and the sealant layer are bonded together, the thin film layer side of the inorganic material or the like is used as the adhesive surface with the intermediate layer, and the polypropylene resin layer is laminated so as to be the innermost surface. Incidentally, when the arrangement of each layer of the packaging material for heat sterilization of the present invention is illustrated including a printing layer and an adhesive layer, from the outside to the surface layer /
The order is print layer / adhesive layer / intermediate layer / adhesive layer / thin film layer of inorganic material / non-oriented polypropylene resin layer.

In the thin film layer, silicon oxide (SiO 2
The thin film layer of _X ) and alumina (Al ₂ O ₃ ) has a high gas barrier property and is transparent, and therefore can be particularly preferably used when the contents are desired to be seen from the outside as a packaging material. In the sealant layer as described above, the thickness of the thin film layer such as an inorganic substance is usually 10 to 10
The range is about 10,000Å, preferably 100 to 1
It is in the range of 10,000Å. If the thickness is less than 10Å, sufficient barrier properties cannot be obtained, and the thickness is 100,000.
If it exceeds Å, it becomes hard and brittle, and the barrier property corresponding to the thickness cannot be obtained, which is also disadvantageous in terms of manufacturing cost. The thickness of the non-oriented polypropylene resin layer is
Usually, it is in the range of 20 to 150 μm, preferably 30.
Is in the range of up to 120 μm. When the thickness is less than 20 μm, the heat-sealing strength is low when processed into a pouch as a laminated film, and the seal part may be damaged during heat sterilization or subsequent handling, which is not preferable.
If the thickness exceeds 150 μm, the sealing strength will not be further increased, but rather the workability will be lowered and the cost will be increased, which is not preferable.

By imparting a gas barrier property to the sealant layer in this manner, not only the transfer of odorous components to the contents can be prevented, but also the invasion of oxygen from the outside can be prevented. There is also an advantage that the gas barrier material used for the above can be omitted. The packaging material for heat sterilization of the present invention can be obtained by laminating each of the layers described above, and for the lamination, a dry laminating method using a urethane adhesive or the like is usually used. Then, the produced laminated film is further bag-shaped to be used, if necessary. The shape of the bag is not particularly limited, and for example, a three-way seal type, a pillow type, a gusset type, a standing pouch type, etc. can be freely selected.

[0016]

The packaging material for heat sterilization of the present invention has a multi-layer structure in which a plurality of layers are laminated, and the innermost layer thereof is a non-oriented polypropylene resin having a thin film layer of an inorganic substance or an inorganic substance containing an organic substance. Is used, and the thin film layer side of the inorganic material or the like is laminated on the adhesive surface, and the non-oriented polypropylene resin layer side is the innermost surface. Therefore, since the thin film layer such as an inorganic material has a gas barrier property, it prevents odorous components such as an adhesive from migrating to the packaged contents side, and the non-oriented polypropylene resin layer is 100 ° C to 130 ° C. It functions as a sealant that can withstand a degree of heat sterilization.

[0017]

Next, the present invention will be described in more detail with reference to the drawings and embodiments. FIG. 1 and FIG. 2 are schematic cross-sectional views showing the configuration of one embodiment of the packaging material for heat sterilization of the present invention. However, the present invention is not limited to these. In FIG. 1, a packaging material 10 for heat sterilization comprises a surface layer 1, an adhesive layer 6a, an intermediate layer 2-1, an adhesive layer 6b,
The innermost layer 5 composed of a thin film layer 3 of inorganic material and a non-oriented polypropylene resin layer 4 is laminated in this order. The packaging material 10 for heat sterilization shown in FIG. 2 has a surface layer 1, an adhesive layer 6a, an intermediate layer 2-1, and an adhesive layer 6 from the outside.
b, the intermediate layer 2-2, the adhesive layer 6c, and the innermost layer 5 composed of the thin film layer 3 of an inorganic material and the non-oriented polypropylene resin layer 4 are laminated in this order. The packaging material for heat sterilization of the present invention has the configuration of the innermost layer defined as described above, but the configuration of the surface layer and the intermediate layer depends on the type and amount of the packaged contents. , Its material and the number of layers can be freely set.

Example 1 A surface layer (outermost layer) having a thickness of 12
Using a PET film of μm [Spett T4102 manufactured by Toyobo Co., Ltd.], A having a thickness of 7 μm as the first intermediate layer
L foil and O as a second intermediate layer with a thickness of 15 μm
N film (Bonir RX, manufactured by Kojin Co., Ltd.) was used, and the innermost layer (sealant layer) had a thickness of CP of 70 μm.
P film [ZK93K Toray Synthetic Film Co., Ltd.]
In addition, a film in which silicon oxide (Si O _X ) is previously provided by vacuum vapor deposition to a thickness of 200 Å as a thin film layer of an inorganic material [the bonding surface of this film is a vapor deposition surface of silicon oxide (Si O _X )] is used. , These two films from the outside in the order of surface layer / first intermediate layer / second intermediate layer / innermost layer by dry lamination method, two-component mixed urethane adhesive [Takelac A515 / Takenate A50 Takeda Pharmaceutical Co., Ltd. )
Manufactured by the manufacturer, the coating amount is 4 g / m ² (solid content)
Then, the packaging material for heat sterilization of Example 1 was prepared by sequentially adhering.

(Example 2) The same procedure as in Example 1 was carried out except that only the second intermediate layer ON film was removed from the configuration of Example 1, and the heat sterilization of Example 2 was performed. The packaging material was created.

(Comparative Example 1) In the structure of Example 1, except for the vapor deposition layer of the silicon oxide (SiO _x ) vapor deposition CPP film used as the innermost layer, a CPP film having a thickness of 70 μm was used, and all were made. The packaging material for heat sterilization of Comparative Example 1 was prepared by processing in the same manner as in Example 1.

(Comparative Example 2) In the structure of Example 2, except that only the vapor-deposited layer of the silicon oxide (SiO _x ) vapor-deposited CPP film used as the innermost layer was removed and a CPP film having a thickness of 70 μm was used, The packaging material for heat sterilization of Comparative Example 2 was prepared by processing in the same manner as in Example 2.

(Test and Evaluation of Packaging Materials for Heat Sterilization of Examples and Comparative Examples) Example 1 prepared as described above,
The packaging materials for heat sterilization of 2 and Comparative Examples 1 and 2 were formed into a three-sided seal type bag having a width of 130 mm and a length of 170 mm (including a heat-sealing portion of 10 mm width) by a conventional bag-making process. 100 test pouches were prepared for each. 180ml each of mineral water to this test pouch
After filling, degassing and sealing with a heat seal, using a pressurized hot water retort sterilizer, 120 ° C, 2.1 kg / cm ² , 3
It was subjected to a pressure heat sterilization treatment (retort treatment) for 0 minutes and subjected to the following test.

(1) Sensory test on influence of odor component of packaging material, especially adhesive on contents (mineral water) 20 untreated mineral water prepared separately by 20 panelists for each sample which has been subjected to retort treatment In comparison with, evaluate the change in taste and odor according to the following criteria,
The results are shown in Table 1 with the symbols of the most evaluations. Evaluation Criteria (Symbols) ○: Almost no change in taste and odor △: Slight change in taste or odor ×: Significant change in taste or odor

(2) Drop Test In order to evaluate the strength of the packaging material for heat sterilization of the present invention after retort treatment, each of the above samples was stored at a temperature of 3 ° C. for 1 week, and then 20 bags of 120 cm each were stored. From the height, continuous 10 with the last heat-sealed line facing down.
A drop test was conducted under the condition of spontaneously dropping once, and the number of broken bags is shown in Table 1.

[0025]

[Table 1] (Test results)

As is clear from the results in Table 1, the samples of Examples 1 and 2 using the packaging material for heat sterilization of the present invention and the samples of Comparative Examples 1 and 2 using the conventional packaging material for heat sterilization. In and, the drop test after the retort treatment and the low temperature storage showed that both were good without a broken bag, but the results of the sensory test on taste and odor after filling with mineral water and retort treatment showed that the results of Example 1 While the samples of No. 2 and 2 were good with almost no change in taste and odor,
Both the samples of Comparative Examples 1 and 2 had a change in the taste and odor of the mineral water due to the influence of the odor component of the adhesive and the like, and the deterioration of the flavor occurred.

[0027]

As described in detail above, according to the packaging material for heat sterilization of the present invention, it can withstand the high temperature treatment of pressure heat sterilization after filling the contents and has the necessary mechanical strength and at the same time, It is possible to provide a packaging material that does not impair the flavor of the food, which is the content, without migration of odorous components to the content due to the adhesive or the like used for laminating each layer. Further, as the adhesive itself for dry lamination, one having a strong odor could not be used so far, but according to the present invention, the adhesive function such as the adhesive strength and the curing speed is not so much concerned about the odor. To be widely selected,
It is a major contribution to the provision of packaging materials for heat sterilization with excellent productivity and performance.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the constitution of an embodiment of a packaging material for heat sterilization of the present invention.

FIG. 2 is a schematic cross-sectional view showing the constitution of another embodiment of the packaging material for heat sterilization of the present invention.

[Explanation of symbols]

1 Surface Layer 2-1, 2-2 Intermediate Layer 3 Thin Film Layer of Inorganic Material 4 Non-Oriented Polypropylene Resin Layer 5 Innermost Layer 6a, 6b, 6c Adhesive Layer 10 Packaging Material for Heat Sterilization

Claims (1)

[Claims] 1. A packaging material for heat sterilization in which a plurality of layers are laminated, wherein the innermost layer contains an innermost layer made of a non-oriented polypropylene resin, and an outer surface of the innermost layer contains an inorganic substance or an organic substance. A packaging material for heat sterilization, comprising: