JPH10119203A - Laminate and wrapping body using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate in which high bag-breaking resistance is maintained at the time of heat treatment of boiling and a retort, in particular even at the time of air-containing boiling treatment and to provide a wrapping body using it. SOLUTION: The laminate contains a polyamide base material film and a sealant film formed on the polyamide base material film. Sealing energy in the vertical direction and the cross direction, which is measured in hot water at 90 deg.C, is >=50kg.mm. At least the outermost layer of the sealant film of the laminate is a nonstretched polypropylene film consisting of resin composition which contains both 100 pts.wt. ethylene random copolymerization polypropylene polymer with 2-8wt.% ethylene content and 0-7 pts.wt. polyolefin-based three- dimensional random copolymerization elastomer consisting of ethylene, propylene and butene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate and a package using the laminate, and more specifically, for example, a packaging bag for water-containing foods and chemicals, or a boiling water treatment or a retort treatment. And more particularly to a package for an aerated boil which is an extremely severe treatment.

[0002]

2. Description of the Related Art Biaxially stretched polyamide films are excellent in toughness, pinhole resistance, bending resistance and heat resistance, and are widely used for various purposes. When such a polyamide film is used as a package, a sealant film is generally provided on at least one side by a dry lamination method or an extrusion lamination method to form a laminate. An adhesive layer or a printing layer is formed between the polyamide film and the sealant film as necessary. Then, a package such as a bag is prepared using the laminate, and after filling the contents, the opening is heat-sealed. Such a package is used for packaging seasonings such as miso and soy sauce, moisture-containing foods such as soups and retort foods, and medicines.

[0003] In recent years, the real culture has become stronger due to the improvement of food culture, and the switching from dry noodles to fresh noodles has also been promoted in instant noodles. In the case of the raw noodle type, heat sterilization is performed after the raw noodle is hermetically packaged. Since this heat sterilization treatment is performed in an aerated state,
There is a large stress in the seal portion due to expansion of the air and water vapor inside the seal by heat. For this reason, the water-resistant adhesiveness required for conventional packaging materials alone is insufficient in characteristics, and the package has characteristics that can withstand the pressure of air and water vapor inside the sealed body, that is, bag-breaking resistance. Required. In recent years, aerated boil conditions have become more severe in order to meet high taste demands.

[0004]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks, and an object of the present invention is to provide high bag-breaking resistance even during heat treatment of a boil, a retort or the like, particularly during an aerated boil treatment. It is intended to provide a laminate that can be maintained, and a package using the same.

[0005]

Means for Solving the Problems The present invention relates to (1) a laminate comprising a polyamide base film and a sealant film formed on the polyamide base film; Characterized in that the sealing energy in the vertical direction and the horizontal direction measured in the step (a) is 50 kg · mm or more. The preferred embodiment is as follows. (2) The stress in at least one of the vertical and horizontal directions when stretched by 75% in hot water at 90 ° C. is 6.5 × 10 ⁷
By using a polyamide base film that is Pa or less
The laminate of (1). (3) Sealant film, at least in its outermost layer,
The laminate according to (1) or (2), having a layer comprising a resin composition containing an ethylene random copolymerized polypropylene polymer having an ethylene content of 2 to 8% by weight. (4) The laminate of (3), wherein the resin composition further contains a polyolefin-based tertiary random copolymer elastomer in an amount of 7 parts by weight or less based on 100 parts by weight of the ethylene random copolymerized polypropylene polymer. (5) The laminate according to (4), wherein the polyolefin-based ternary random copolymer elastomer comprises ethylene, propylene and butene. (6) The sealant film is a non-stretched film (3) ~
The laminate according to any one of (5). (7) The laminate according to any one of (1) to (6), further comprising an adhesive layer formed between the polyamide base film and the sealant film. (8) The laminate according to (7), wherein an adhesion modification layer is further formed between the polyamide base film and the adhesive layer. Further, the present invention relates to (9) a package formed by sealing the laminate of any one of (1) to (8) with sealant films inside each other. Preferably, the package (10) is in the form of a bag.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The laminate of the present invention contains a polyamide base film and a sealant film formed on the polyamide base film. The polyamide base film in the present invention is formed of a resin composition containing a polyamide resin. Examples of the polyamide resin include a polyamide resin obtained by polycondensation of a lactam having three or more ring members, and an ω-amino acid. Examples thereof include a polyamide resin obtained by polycondensation, and a polyamide resin obtained by polycondensation of a dibasic acid and a diamine.

Specific examples of the lactams having three or more rings include ε-caprolactam, enantholactam, caprylactam, lauryl lactam and the like. Specific examples of the above ω-amino acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11
-Aminoundecanoic acid and the like.

Specific examples of the above dibasic acids include adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandionic acid, dodecadionic acid, hexadecadionic acid, eicosandioic acid and eicosandionic acid. Examples thereof include sadienedioic acid, 2,2,4-trimethyladipic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and xylylenedicarboxylic acid.

Specific examples of the above diamines include ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, pentamethylenediamine, undecamethylenediamine, 2,2,4 (or 2,4,4)- Trimethylhexamethylenediamine,
Cyclohexanediamine, bis- (4,4'-aminocyclohexyl) methane, meta-xylylenediamine and the like can be mentioned.

Specific examples of the polyamide resin obtained include nylon 6, nylon 7, nylon 11, nylon 12, nylon 6,6, nylon 6,9, nylon 6,
11, nylon 6,12, nylon 6T, nylon 6
I, nylon MXD6, nylon 6 / 6.6, nylon 6/12, nylon 6 / 6T, nylon 6 / 6I, nylon 6 / MXD6 and the like.

[0011] In addition to the polyamide resin, other than the polyamide resin, unless the purpose and performance are impaired,
Various additives such as antioxidants, light stabilizers, antigelling agents, lubricants, antiblocking agents, pigments, antistatic agents, and surfactants may be contained.

The polyamide base film can be formed by a known film forming method, for example, a T-die method, an inflation method or the like. The polyamide base film may be a single-layer film or a multi-layer film formed by coextrusion or the like.

In order for the laminate of the present invention to have a sealing energy of 50 kg · mm or more in the vertical and horizontal directions when measured in hot water at 90 ° C. (hereinafter also referred to as hot water sealing energy), It is preferable to use a polyamide base film having the following characteristics. That is, 90
At least one of the stress in the longitudinal direction or the transverse direction when the film is stretched by 75% in hot water at 75 ° C. (hereinafter, also simply referred to as the stretching stress in hot water) is preferably 6.5 × 10 ⁷ Pa or less; It is more preferably at most 6.2 × 10 ⁷ Pa, particularly preferably at most 6.0 × 10 ⁷ Pa. 5. Elongation stress
Means for reducing the pressure to 5 × 10 ⁷ Pa or less can be achieved, for example, by selecting the material of the polyamide base film and the film forming conditions.

[0014] The sealant film in the present invention is formed on a polyamide base film in order to impart thermal adhesion to the laminate. The laminate of the present invention has a length of 50 kg in the vertical and horizontal directions when measured in hot water at 90 ° C.
In order to have a sealing energy of at least mm, the sealant film has at least as its outermost layer a layer made of a resin composition containing an ethylene random copolymerized polypropylene polymer having an ethylene content of 2 to 8% by weight. Is preferred. When the ethylene content of the above polymer is less than 2% by weight, the obtained laminate has a low hot water sealing energy and thus has poor bag breaking resistance at the time of air-containing boiling treatment, and also has low temperature heat sealing property and impact resistance. Is undesirably reduced. On the other hand, when the content exceeds 8% by weight, the obtained laminate has undesirably reduced blocking resistance, rigidity and heat resistance. The ethylene content is preferably 3-7% by weight
It is.

[0015] In order not to deteriorate the heat sealability at low temperatures, the melt float (MI) measured at 230 ° C in accordance with JIS K7210 of an ethylene random copolymerized polypropylene polymer is 3 to 15 g / 10 minutes. Is preferred.

The method for producing the ethylene random copolymerized polypropylene polymer is not particularly limited.
The liquid phase method may be used. The catalyst is not limited, and may be a Ziegler-Natta catalyst or a metallocene catalyst. It is preferable to use a polymer that has been deodorized by, for example, a reduced pressure treatment.

From the viewpoint that the hot water sealing energy of the obtained laminate can be further increased, the above resin composition is used in a range of 7 parts by weight or less based on 100 parts by weight of the ethylene random copolymerized polypropylene polymer. It is preferable to contain an original random copolymer elastomer. As monomers constituting the polyolefin-based ternary random copolymer elastomer, ethylene, propylene,
Three types are selected from butenes and the like, and preferably ethylene-
It is a tertiary random copolymer elastomer of propylene-butene. On the other hand, if the blending amount of the polyolefin-based tertiary random copolymer elastomer is more than 7 parts by weight, it is not preferable because the hot water sealing energy of the obtained laminate is reduced and the bag-breaking resistance at the time of the aerated boiling treatment is inferior.

The polyolefin-based tertiary random copolymer elastomer preferably has a bigat softening point of 60 ° C. or less and a surface hardness of 80 ° or less from the viewpoint that a preferable elasticity can be imparted to the laminate. , That M
I can also maintain the heat sheet property at low temperatures,
It is preferable to use one with 15 g / 10 minutes.

As a method for making both the longitudinal and transverse sealing energies in hot water at 90 ° C. not less than 50 kg · mm, an ethylene random copolymer polypropylene having an ethylene content of 2 to 8% by weight is used. A polypropylene-based unstretched film comprising 0 to 7 parts by weight of a tertiary random copolymer elastomer composed of ethylene, propylene and butene with respect to 100 parts by weight of a polymer, and It is a particularly preferred embodiment to use a polyamide base film having an elongation stress in at least one of the vertical direction and the horizontal direction at the time of% elongation of 6.5 × 10 ⁷ Pa or less.

The purpose of the sealant film is to
Unless the performance is impaired, if necessary, antioxidants, light stabilizers, lubricants, antiblocking agents, pigments, antistatic agents,
An additive such as a surfactant may be blended.

In this case, the sealant film may be a single layer or two or more layers. When the sealant film is composed of two or more layers, for example, a base layer and a seal layer, the seal layer which is the outermost layer of the laminate is formed. Is preferably the above composition, and there is no particular limitation on the thickness ratio between the seal layer and the base layer. In this case, the sealant film is laminated with the base layer facing the polyamide base film. Further, a laminate layer may be formed on the surface of the base layer opposite to the surface on which the seal layer is formed. In this case, the sealant film is laminated with the laminate layer facing the polyamide base film.

In order to improve the adhesion between the polyamide base film and the sealant film, an adhesive layer may be further provided between them. The thickness and type of the adhesive layer are not particularly limited as long as they do not prevent the hot water sealing energy required for the laminate of the present invention from being realized.
It is preferable to use a type that performs a crosslinking reaction. Examples of such a resin include a polyester resin, a polyurethane resin, a polyamide resin, a polyether resin, and a complex thereof. Examples of the crosslinking agent include isocyanate compounds, oxazoline compounds, epoxy compounds, silane compounds, melamine compounds, and phenol formaldehyde resins. Among these, it is more preferable to use a crosslinked polymer having a glass transition point (Tg) of 10 ° C. or less, and it is further preferable that the Tg is 8 ° C.
The following is the use of a crosslinked polymer. Tg is 1
If the temperature exceeds 0 ° C., the adhesive layer may become brittle, which is not preferable.

It is preferable to further form an adhesion reforming layer between the polyamide base film and the adhesive layer in that the hot water sealing energy can be easily applied to the laminate of the present invention. As a material of the adhesion reforming layer, for example,
Polyester resin isocyanate compound, oxazoline compound, melamine compound, epoxy compound, those crosslinked using a crosslinking agent such as a silane compound, acrylic resin, polyurethane resin, and acrylic graft copolymer of polyester resin and polyurethane resin, And those obtained by crosslinking them with the above-mentioned polyfunctional crosslinking agent.

The adhesion-modified layer may contain additives such as an antistatic agent, an inorganic lubricant and an organic lubricant as long as the effects of the present invention are not impaired.

A printing layer may be provided between the polyamide base film and the adhesive layer or between the polyamide base film and the adhesion modifying layer, and the printing method and pattern may be arbitrarily determined. Good.

The laminate of the present invention has a vertical and horizontal sealing energy measured in hot water of 90 ° C. of 50 kg.
Mm or more, preferably 60 kg · mm or more, more preferably 65 kg · mm or more. Only by satisfying such sealing energy in hot water at 90 ° C. can high bag-breaking resistance be provided. In this specification, “9
The term "sealing energy measured in hot water at 0 ° C." means that the laminate of the present invention is heat-sealed at a temperature of 180 ° C. and a pressure of 2 kg / cm ² × 1 second, with the sealant film faces together. After holding in hot water at a temperature of ° C., the T-shaped peeling is performed at a predetermined speed, and the integrated value of stress and elongation applied to the seal until it breaks. The “longitudinal direction” and “lateral direction” refer to the maximum direction of the molecular orientation of the film and the direction perpendicular to the direction, respectively. The means for increasing the sealing energy is not limited, but adoption of a sealant film having the above-described composition, use of a polyamide base film having an elongational stress as described above, and the like are employed.

The package of the present invention is obtained by heat-sealing and bag-making the above-mentioned laminated body inside the sealant film. Such a package has excellent hot water sealing energy particularly when subjected to boiling treatment in a state where the package is air-sealed and hermetically sealed in the bag, so that the package exhibits excellent breakage resistance. Of course, there is no restriction on use as another packaging form.

Here, the gas-containing state means that the contents are sealed in a state containing a gas, and the gas is air, oxygen, carbon dioxide or the like. There is no particular limitation on the use of gas, but usually 30 cc or more is usually enclosed in a package for raw noodles.

The boiling state in the present invention is a state in which boiling and retorting are performed in hot water or steam.
The temperature and time are not particularly limited, but are often performed at 70 ° C. or higher from the viewpoint of sterilization effect.

Such a package is not only used for packaging bags containing water-containing foods and medicines, but also for severe treatments such as boiling water treatment and retort treatment, particularly for packages containing air boil, which are extremely severe treatments. Useful as a body.

[0031]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and the present invention is not limited thereto. Modifications can be made and implemented, all of which are included in the technical scope of the present invention. The measurement of the sealing energy of the laminate in hot water and the evaluation of the aerated boil-puncture properties were performed according to the following methods.

1. Measurement of the sealing energy of the laminate in hot water The laminate was measured 15 mm x 5 mm (vertical 15 mm x horizontal 5 mm when measuring the vertical sealing energy, and vertical when measuring the sealing energy in the horizontal direction). Direction 5mm ×
The sample is cut into a sample (width: 15 mm), the sealant films of the sample are combined, and one end is heat-sealed at a temperature of 180 ° C. and a pressure of 2 kg / cm ² × 1 second. This is held in hot water of 90 ° C., and T
Perform mold release. At this time, the relationship between the stress applied to the seal and the elongation at the time of elongation at a speed of 100 mm / min until breakage was recorded, and the integrated value was defined as the seal energy.

2. Evaluation of the bag-breaking resistance of the laminate at the time of the pneumatic boil treatment The laminate was formed into a three-sided bag having an inner size of 13 cm × 13 cm, and 200 cc of water and 200 cc of air were filled therein and sealed. The sealed bag was boiled in hot water at 99 ° C. for 60 minutes, and the bag breaking rate of the sample at the sealed portion was calculated by the following formula. Breaking rate (%) = (number of sealed bags torn / number of sealed bags tested) × 100

3. Measurement of Elongation Stress of Polyamide Film in Hot Water The film is gripped in a 90 ° C. hot water by a film tensile tester and stretched to 75% at a speed of 200 to 300 mm / min. The stress at this time is read from a stress-elongation curve.

Example 1 (Preparation of Coating Solution for Adhesion-Modifying Layer) In a reactor equipped with a stirrer, a thermometer, a reflux device, and a fixed-rate dropping device, 75 parts of a polyester resin having the following composition, 56 parts of methyl ethyl ketone,
Charge 19 parts of isopropyl alcohol and heat at 65 ° C.
Stir to dissolve the resin. Then, methacrylic acid 17.
A mixture of 5 parts and 7.5 parts of ethyl acrylate,
A solution obtained by dissolving 1.2 parts of azobisdimethylvaleronitrile in 25 parts of methyl ethyl ketone was added to a solution of 0.1 part each.
Dropping into the polyester solution at a rate of 2 ml / min,
Stirring was continued at the same temperature for another 2 hours. After sampling (5 g) for analysis from the reaction solution, 300 parts of water and 25 parts of triethylamine were added to the reaction solution, and the mixture was stirred for 1 hour to obtain an aqueous dispersion. Thereafter, the temperature of the dispersion is set to 100 ° C.
, And the methyl ethyl ketone, isopropyl alcohol and excess triethylamine were removed by distillation. The resulting aqueous dispersion of the acrylic graft polyester resin is white, has an average particle diameter of 300 nm, and has a B-type viscosity of 50.
cps (25 ° C.). The polyester portion of the solid copolymer was hydrolyzed, and the molecular weight of the acrylic polymer portion was measured by GPC.
000. This aqueous dispersion of the acrylic graft polyester resin was diluted with water so as to have a solid content of 20% to obtain a coating liquid for an adhesion-modified layer. <Composition of Polyester> Dicarboxylic acid component Terephthalic acid: 48 mol% Isophthalic acid: 39 mol% Sebacic acid: 9 mol% Fumaric acid: 4 mol% Diol component Neopentyl glycol: 50 mol% Ethylene glycol: 50 mol%

(Preparation of Polyamide Film and Formation of Adhesion-Modified Layer) A composition comprising 98 parts of polycaproamide resin and 2 parts of polyamide elastomer resin was mixed at 260 ° C. by a screw type extruder, and then melt-extruded from a T-die. Then, it was cooled on a cooling drum to obtain an unstretched polyamide film. Then, the unstretched film was subjected to 3.1 at 50 ° C.
The film was stretched twice as long. On one surface of the obtained polyamide film (elongation stress in hot water: 6.0 × 10 ⁷ Pa), apply the coating solution for the adhesion modifying layer so that the coating amount after drying is 4 g / m ^2. It was applied by a gravure method, and then dried so that the moisture content of the polyamide film became 1%. Then, after stretching 4 times in the horizontal direction at 125 ° C., heat-fixing was performed at 215 ° C. while relaxing 6% in the horizontal direction, and the thickness was 25%.
A polyamide film on which a μm adhesion modified layer was formed was obtained.

(Preparation of Sealant Film) A two-layer unstretched propylene film (C) comprising a base layer and a seal layer
PP film) was used as the film for the sealant film. This CPP film has the following composition. The base layer is composed of an ethylene random copolymerized polypropylene polymer having an ethylene content of 6.5% by weight (MI =
5.5) 90 parts by weight, 10 parts by weight of a polyolefin tertiary random copolymer elastomer (MI = 5.7) comprising ethylene, propylene and butene having a bigat softening point of 40 ° C. or less and a surface hardness of 68 °, Average particle size 4μm
Of amorphous silica and 0.05 part by weight of erucamide. The sealing layer is
97 parts by weight of an ethylene random copolymerized polypropylene polymer (MI = 5.5) having an ethylene content of 6.5% by weight; Ternary random copolymer elastomer (MI = 5.
7) 3 parts by weight, 0.1 part by weight of amorphous silica having an average particle size of 4 μm, 0.3 part by weight of spherical zeolite having an average particle size of 5 μm,
And 0.05 parts by weight of erucamide. These compositions were melt co-extruded using separate extruders and T-die cast molded to form a base layer 30
A CPP film having a total thickness of 40 μm was prepared.

(Formation of Adhesive Layer and Lamination of Sealant Film) On the adhesion-modified layer of the polyamide film, an aromatic / aliphatic copolymerized polyester polyol (Tg: -16.degree. After drying a polyester polyurethane-based adhesive (Tg after crosslinking: 5 ° C.) comprising a methylene diisocyanate trimer,
The coating is m ^2, followed by dry lamination according to a conventional method above CPP film to obtain a laminate.

The obtained laminate was measured for sealing energy in hot water at 90 ° C. Further, the bag breaking ratio was measured to evaluate the bag breaking resistance at the time of the air-containing boiling treatment. Table 1 shows the results. The laminate of Example 1 has a sealing energy of 50 kg · m both in the vertical and horizontal directions in hot water.
m, and the bag-breaking resistance during the aerated boiling treatment was also good. This polyamide film laminate was used as a sealed package for raw noodles. However, the occurrence of bag breakage due to thermal expansion in the heat sterilization step was extremely low and was highly practical.

Comparative Example 1 A polyamide film laminate was obtained in the same manner as in Example 1, except that the composition of the seal layer of the CPP film was the same as that of the base layer. About the obtained laminated body, the sealing energy in 90 degreeC hot water was measured. Further, the bag breaking ratio was measured to evaluate the bag breaking resistance at the time of the air-containing boiling treatment. Table 1 shows the results. In the laminate of Comparative Example 1, the sealing energy in the vertical direction and the horizontal direction in the hot water were both lower than 50 kg · mm, and the bag-breaking resistance at the time of the aerated boiling treatment was inferior.

Example 2 (Preparation of polyamide film and formation of adhesion modified layer)
Example 1 was the same as Example 1 except that the coating liquid composed of the acrylic graft polyester resin was not applied.
A polyamide film as a base film was obtained in the same manner as described above. Separately, a linear polyester resin (Vylon 300, manufactured by Toyobo Co., Ltd.) and a polyisocyanate (Coronel L, manufactured by Nippon Polyurethane Co., Ltd.) are used for 100:
The mixture was mixed so that the solid content ratio became 100 (solid content ratio), and then ethyl acetate was added so that the solid content concentration became 4% to prepare a mixed solution. Next, amorphous silica (Sylysia 310, manufactured by Fuji Silysia Chemical Ltd.) was added to this mixture to prevent blocking and impart lubricity so that the solid content concentration was 0.5%. Prepared. This coating solution is gravure coated on the polyamide film so that the coating amount after drying is 3 g / m ^2, and after drying, aging at 40 ° C. for 2 days to form an adhesion modified layer. A 28 μm thick polyamide film was obtained.

(Preparation of Sealant Film) A two-layer unstretched propylene film (C) comprising a base layer and a seal layer
PP film) was used as the film for the sealant film. This CPP film has the following composition. The base layer is composed of an ethylene random copolymerized polypropylene polymer having an ethylene content of 5.5% by weight (MI =
6.2) 90 parts by weight, 10 parts by weight of a polyolefin tertiary random copolymer elastomer (MI = 5.7) composed of ethylene, propylene and butene having a bigat softening point of 40 ° C. or lower and a surface hardness of 68 °, Average particle size 4μm
Of amorphous silica and 0.05 part by weight of erucamide. The sealing layer is
97 parts by weight of an ethylene random copolymerized polypropylene polymer (MI = 6.2) having an ethylene content of 5.5% by weight, a polyolefin comprising ethylene, propylene and butene having a bigat softening point of 40 ° C. or less and a surface hardness of 68 ° Ternary random copolymer elastomer (MI = 5.
7) 3 parts by weight, 0.1 part by weight of amorphous silica having an average particle size of 4 μm, 0.3 part by weight of spherical zeolite having an average particle size of 5 μm,
And 0.05 parts by weight of erucamide. These compositions were melt co-extruded using separate extruders and T-die cast molded to form a base layer 30
A CPP film having a total thickness of 40 μm was prepared.

(Formation of Adhesive Layer and Lamination of Sealant Film) An adhesive was applied on the adhesion-modified layer of the polyamide film in the same manner as in Example 1, and then the above-mentioned CPP was applied.
The film was dry-laminated according to a conventional method to obtain a laminate.

The sealing energy of the obtained laminate in hot water at 90 ° C. was measured. Further, the bag breaking ratio was measured to evaluate the bag breaking resistance at the time of the air-containing boiling treatment. Table 1 shows the results. The laminate of Example 2 had a sealing energy of 50 kg · m in the vertical and horizontal directions in hot water.
m, and the bag-breaking resistance during the aerated boiling treatment was also good. This polyamide film laminate was used as a sealed package for raw noodles. However, the occurrence of bag breakage due to thermal expansion in the heat sterilization step was extremely low and was highly practical.

Comparative Example 2 A laminate was obtained in the same manner as in Example 2 except that the ethylene content of the ethylene random copolymerized polypropylene in the sealing layer of the CPP film was changed to 1.5% by weight. Was. About 90 degreeC about the obtained laminated body.
The sealing energy in hot water was measured. Further, the bag breaking ratio was measured to evaluate the bag breaking resistance at the time of the pneumatic boiling treatment. Table 1 shows the results. The laminate of Comparative Example 2 had a seal energy of 50 in both the vertical and horizontal directions in hot water.
It was lower than kg.mm, and the bag breaking resistance at the time of the aerated boiling treatment was also inferior.

Example 3 (Preparation of polyamide film and formation of adhesion modified layer)
In Example 1, a water dispersion type polyurethane resin (Hydran HW-140) and trimethylolmethane (Beckamine PMN-N, manufactured by Dainippon Ink) were used in place of the acrylic graft polyester resin instead of the acrylic graft polyester resin.
Was obtained in the same manner as in Example 1 except that a polyamide film having a solid content ratio of 100: 20 was used.

(Formation of Sealant Film) A base layer, a seal layer formed on the base layer, and a laminate layer formed on the surface of the base layer opposite to the seal layer forming surface
An unstretched propylene film having a layer structure (hereinafter referred to as CPP film) was used as a film for a sealant film. This CPP film has the following composition. The base layer comprises 90 parts by weight of an ethylene random copolymerized polypropylene polymer (MI = 5.5) having an ethylene content of 6.5% by weight, a bigat softening point of 40 ° C. or lower and a surface hardness of 68.
° polyolefin tertiary random copolymer elastomer comprising ethylene, propylene and butene (MI =
5.7) A composition comprising 10 parts by weight, 0.1 part by weight of amorphous silica having an average particle size of 4 μm, and 0.05 part by weight of erucamide. The seal layer is composed of 97 parts by weight of an ethylene random copolymerized polypropylene polymer having an ethylene content of 6.5% by weight (MI = 5.5), ethylene, propylene having a bigat softening point of 40 ° C. or less and a surface hardness of 68 °. From a composition comprising 3 parts by weight of a polyolefin tertiary random copolymer elastomer (MI = 5.7) comprising butene, 0.3 parts by weight of spherical zeolite having an average particle size of 5 μm, and 0.05 parts by weight of erucamide. Become.
The laminate layer was made of an ethylene random copolymerized polypropylene polymer having an ethylene content of 6.5% by weight (MI = 5.
5) 70 weight parts of an ethylene block copolymer polypropylene polymer having an ethylene content of 9 weight% (MI = 3.
0) 30 parts by weight of amorphous silica having an average particle size of 4 μm 0.1
It consists of a composition consisting of parts by weight. These compositions were melt co-extruded using separate extruders and T-die-casted to form a CPP film having a total thickness of 40 μm, including a base layer of 20 μm, a seal layer of 10 μm, and a laminate layer of 10 μm.

(Formation of Adhesive Layer and Lamination of Sealant Film) An adhesive was applied on the adhesion-modified layer of the polyamide film in the same manner as in Example 1, and then the above CPP was applied.
The film was dry-laminated according to a conventional method to obtain a laminate.

The sealing energy of the obtained laminate in hot water at 90 ° C. was measured. Further, the bag breaking ratio was measured to evaluate the bag breaking resistance at the time of the air-containing boiling treatment. Table 1 shows the results. The laminate of Example 3 had a sealing energy of 50 kg · m in the vertical and horizontal directions in hot water.
m, and the bag-breaking resistance during the aerated boiling treatment was also good. This polyamide film laminate was used as a sealed package for raw noodles. However, the occurrence of bag breakage due to thermal expansion in the heat sterilization step was extremely low and was highly practical.

Comparative Example 3 In Example 3, as the sealing layer of the CPP film,
92 parts by weight of an ethylene random copolymerized polypropylene polymer (MI = 5.5) having an ethylene content of 1.2% by weight,
Polyolefin tertiary random copolymer elastomer composed of ethylene, propylene and butene having a bigat softening point of 40 ° C. or less and a surface hardness of 68 ° (MI = 5.
7) 8 parts by weight, spherical zeolite 0.3 having an average particle size of 5 μm
A laminate was obtained in the same manner as in Example 3, except that a composition comprising parts by weight and 0.05 parts by weight of erucamide was used. About the obtained laminated body, the sealing energy in 90 degreeC hot water was measured. Further, the bag breaking ratio was measured to evaluate the bag breaking resistance at the time of the air-containing boiling treatment. Table 1 shows the results. The laminate of Comparative Example 3 had a sealing energy of 50 kg in both the vertical and horizontal directions in hot water.
Mm, and the bag-breaking resistance during the aerated boiling treatment was poor.

Comparative Example 4 In Example 3, the elongation stress in hot water was 7.0 × 10 ^7.
Example 3 except that a polyamide film of Pa was used.
A laminate was obtained in the same manner as described above. About the obtained laminated body, the sealing energy in 90 degreeC hot water was measured.
Further, the bag breaking ratio was measured to evaluate the bag breaking resistance at the time of the air-containing boiling treatment. Table 1 shows the results. In the laminate of Comparative Example 4, the sealing energy in the vertical direction and the horizontal direction in the hot water were both lower than 50 kg · mm, and the bag-breaking resistance at the time of the aerated boiling treatment was also inferior.

[0052]

[Table 1]

The polyamide film laminate obtained in this example has a high sealing energy in hot water between the polyamide film and the sealant film, and can be suitably used, for example, as a packaging material for water-containing foods. Further, a sealed package formed by sealing and bag-making sealant films using the polyamide laminate is excellent in aerated boil-puncture resistance. The polyamide film laminate was used as a sealed packaging bag for raw noodles. However, the rate of occurrence of bag breakage due to thermal expansion in the heat sterilization step was extremely low, and was highly practical.

As is clear from the above description, the laminate of the present invention has a very high hot water seal energy of 50 kg · mm or more in the vertical and horizontal directions measured in hot water at 90 ° C. Since it has energy, high bag-breaking resistance can be maintained even during heat treatment of a boil, a retort, or the like, particularly during an aerated boil treatment. Therefore, a package using such a laminate is not only a packaging bag for moisture-containing foods and chemicals and the like, but also a severe treatment such as a boiling water treatment and a retort treatment, particularly for an aerated boil which is an extremely severe treatment. Very useful as a package.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tsutomu Isaka 2-2-2, Dojimahama, Kita-ku, Osaka Toyobo Co., Ltd.

Claims (10)

[Claims] 1. A laminate comprising a polyamide base film and a sealant film formed on the polyamide base film, wherein a seal energy in a longitudinal direction and a transverse direction measured in hot water at 90 ° C. Is 50kg ・ mm
A laminate characterized by the above. 2. Stress in at least one of a longitudinal direction and a transverse direction when stretched 75% in hot water at 90 ° C. is 6.
2. The laminate according to claim 1, wherein the laminate is made of a polyamide base film having a pressure of 5 × 10 ⁷ Pa or less. 3. 3. The sealant film according to claim 1, wherein at least the outermost layer has a layer made of a resin composition containing an ethylene random copolymerized polypropylene polymer having an ethylene content of 2 to 8% by weight. 3. The laminate according to 1 or 2. 4. The resin composition according to claim 3, further comprising a polyolefin tertiary random copolymer elastomer in an amount of 7 parts by weight or less based on 100 parts by weight of the ethylene random copolymerized polypropylene polymer. The laminate according to item 1. 5. The laminate according to claim 4, wherein the polyolefin-based ternary random copolymer elastomer comprises ethylene, propylene and butene. 6. The laminate according to claim 3, wherein the sealant film is a non-stretched film. 7. The laminate according to claim 1, wherein an adhesive layer is further formed between the polyamide base film and the sealant film. 8. The laminate according to claim 7, wherein an adhesion modification layer is further formed between the polyamide base film and the adhesive layer. 9. A package, wherein the laminate according to claim 1 is sealed with the sealant films inside. 10. The package according to claim 9, which is in the form of a bag.