JP3266070B2 - Gas barrier laminated film for boil treatment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is excellent in gas barrier properties and moisture proof properties, which are important properties in packaging films for fresh foods, processed foods, pharmaceuticals, medical equipment, electronic parts and the like.
The present invention also relates to a gas barrier laminate film having excellent handleability. The “film” in the present invention is intended to represent films and sheets.

[0002]

2. Description of the Related Art In recent years, food packaging forms have changed drastically due to changes in food distribution forms and dietary habits, and the required characteristics of packaging films have become strict. Regarding foods, if the quality deteriorates due to temperature changes in the distribution and sales process, moisture, oxygen, ultraviolet rays, and the effects of microorganisms such as bacteria and mold, not only loss in sales but also food hygiene will be significant. It is a problem. As a method of preventing such quality deterioration, antioxidants and preservatives have been added directly to foods in the past, but in recent years, regulations on food additives have become stricter from the standpoint of consumer protection. Is required to be reduced or not added. Under such circumstances, there is a demand for a packaging film which has a low gas and moisture permeability and which does not cause deterioration in food quality due to freezing, boiling, retorting and the like.

[0003] In the packaging of fish meat, animal meat, shellfish, etc., in order to suppress the oxidation and deterioration of proteins and oils and fats, and to maintain the taste and freshness, a packaging material having good gas barrier properties for blocking air permeation is used. This is very important. If wrapped in a gas barrier film, the aroma of the contents is retained and the permeation of moisture is prevented, so that the moisture absorption of dried products is suppressed, and in the case of hydrated products, deterioration and solidification due to evaporation of moisture are suppressed. In addition, fresh flavor during packaging can be maintained for a long time.

[0004] For these reasons, kneaded products such as kamaboko, dairy products such as butter and cheese, miso, tea, coffee,
Gas barrier properties and moisture resistance required for packaging films for confectionery such as hams and sausages, instant foods, castella, biscuits and the like are regarded as extremely important properties. These properties are not limited to food packaging films as described above, but also in medical products that need to be handled under aseptic conditions, and in packaging films for electronic components that require rust prevention. Required.

[0005] Films having excellent gas barrier properties include:
Known are those in which a metal foil such as aluminum is laminated on a plastic film, those coated with polyvinylidene chloride or an ethylene vinyl alcohol copolymer, and the like. Further, as a device using an inorganic thin film other than a metal, a device in which a deposit layer of silicon oxide, aluminum oxide, or the like is laminated is also known.

[0006] These conventional gas barrier films include:
The following problems have been pointed out respectively. As a gas barrier layer, a laminate of metal foil such as aluminum has good gas barrier properties and is also economical, but because it is opaque, the contents at the time of packaging cannot be seen, and microwaves do not transmit. Cannot be used for microwave ovens.

On the other hand, those coated with a gas barrier layer of vinylidene chloride, ethylene vinyl alcohol copolymer, or the like do not have sufficient gas barrier properties against water vapor, oxygen, and the like, and the performance is remarkably deteriorated particularly during or after high-temperature treatment. Also, with respect to polyvinylidene chloride, there is a concern about the effect on the global environment because chlorine gas is generated during incineration.

[0008] In view of this, a resin film having a layer formed of an inorganic material such as silicon oxide or aluminum oxide as a gas barrier layer has been proposed. Inorganic deposit layers such as silicon oxide and aluminum oxide are often formed by depositing these inorganic substances on a polyester film (PET). However, the laminated films using these inorganic coatings as gas barrier layers have a problem that the film strength is insufficient, and the gas barrier properties are deteriorated by boiling treatment or retort treatment. For example, PET / deposited layer /
In the case of a film having a laminated structure such as an adhesive layer / stretched nylon (ONY) / adhesive layer / unstretched polypropylene (CPP), the stretched nylon shrinks at the time of boiling treatment or retort treatment, and cracks or peeling of the vapor deposition layer occurs. The gas barrier properties of the laminated film deteriorate. However, if the lamination of nylon is eliminated and a laminated structure of PET / deposited layer / adhesive layer / PET / adhesive layer / unstretched polypropylene (CPP) is used, insufficient strength at the time of dropping becomes a serious problem.

[0009] Therefore, a laminated film having both characteristics of gas barrier properties and strength has been studied. For example, a method of using stretched nylon having a reduced heat shrinkage rate by a heat treatment as a deposition base material (Japanese Patent Publication No. 7-12649)
JP-A No. 7-2765), or laminated nylon having reduced shrinkage during heat treatment to impart strength.
No. 71) has been proposed. However, all of these methods have a problem in that the manufacturing process of nylon and the process of transporting and storing are complicated, which is not suitable for practical use. In addition, nylon having a reduced shrinkage during high-temperature treatment (Japanese Patent Publication No. 7-12649 discloses that the sum of the absolute values of the dimensional change rates in the vertical and horizontal directions by heat treatment at 120 ° C. for 5 minutes is 2%. Even if it is specified below), if the boiling (boil) treatment that is a high-temperature hot water treatment is performed, the entire laminated film shrinks due to the shrinkage of the nylon film, and as a result, the gas barrier property deteriorates. There is room for improvement.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has both excellent strength characteristics, gas barrier properties and moisture proof properties, and impairs excellent gas barrier properties even after boiling treatment. It is an object of the present invention to provide a gas barrier laminate film which has no heat sealing property and has good heat sealability.

[0011]

Means for Solving the Problems The gas barrier laminate film for boil treatment of the present invention is a laminated film having at least three layers of a polyamide resin film layer, an inorganic vapor deposition layer and a polyolefin resin film layer, The gist lies in satisfying the following conditions (1) to (3).

(1) The compression elastic modulus in hot water at 95 ° C. per unit sectional area of the polyolefin resin film layer is 8 kgf / mm ² or more.

(2) The Vicat softening point of the polyolefin resin film layer is 145 ° C. or less.

(3) The shrinkage (%) of the laminated film in hot water at 95 ° C. is 95% of the polyamide resin film layer.
It is less than 0.7 times the shrinkage ratio (%) in hot water at ° C.

The above-mentioned polyolefin resin film layer comprises:
The structure in which two or more kinds of polyolefin resin film layers are laminated and the Vicat softening point of each film layer is 100 ° C. or more is the gas barrier property, heat sealing property and strength of the obtained laminated film. Is one of the preferred embodiments of the present invention. Oxygen permeability after boiling in hot water is 15cc / m ²
Atm · day or less is desirable as the gas barrier performance layer film, and the gas barrier laminate films are heat-sealed at various temperatures for 2 seconds at ² kgf / cm ² and then subjected to a 90 ° peel test. When the heat-sealing temperature when the peel strength is 500 g / 15 mm or more is defined as the heat-sealing start temperature, when the heat-sealing start temperature is 135 ° C. or less, a gas barrier laminate film excellent in heat-sealing is obtained. be able to.
Further, it is also preferable from the viewpoint of handleability that the blocking resistance measured according to ASTM-D1893-67 is 10 g / 20 mm or less. In order to impart heat sealability to the gas barrier laminate film for boil treatment of the present invention, it is recommended that a polyolefin resin film layer be present on the outermost layer.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In order to solve the above-mentioned problems, the present inventors have studied to prevent the influence of shrinkage of a polyamide resin layer itself on the entire laminated film, and have studied a specific polyolefin resin. By laminating the film layers, shrinkage of the laminated film during the boil treatment was suppressed, cracking and peeling of the inorganic vapor deposition layer were prevented, and good gas barrier properties were successfully maintained.

The polyolefin resin film layer provided on the gas barrier laminate film of the present invention must satisfy the following conditions (1) and (2).

(1) The compression elastic modulus in hot water at 95 ° C. per unit sectional area of the polyolefin resin film layer is 8 kgf / mm ² or more.

(2) The Vicat softening point of the polyolefin resin film layer is 145 ° C. or less.

(1) The condition that the obtained laminated film should satisfy (3): The shrinkage rate (%) of the laminated film in hot water at 95 ° C. is 95% of the polyamide resin film layer.
This is a condition necessary to achieve a shrinkage ratio (%) of less than 0.7 times in hot water at 0 ° C. When the gas barrier laminate film is boiled, the polyamide resin film layer shrinks, causing shrinkage stress. The laminated polyolefin-based resin film is compressed following the polyamide resin film layer, and a compressive stress against shrinkage stress is generated. At this time, if the compression elastic modulus in hot water at 95 ° C. per unit cross-sectional area of the polyolefin-based resin film layer is large, the compressive stress increases, so that the shrinkage of the polyamide resin film layer can be suppressed. The shrinkage of the entire film can be suppressed.

Therefore, in the present invention, as the condition (1), 9 per unit sectional area of the polyolefin resin film layer is used.
The compression modulus in hot water at 5 ° C. was specified to be 8 kgf / mm ² or more. If the compressive modulus is less than 8 kgf / mm ² , the effect of shrinkage of the polyamide resin film layer after boiling cannot be suppressed from affecting the entire laminated film, and the shrinkage rate of the gas barrier laminated film becomes large, and the (3) ) Condition cannot be satisfied. A more preferred lower limit of the compression modulus is 15 kgf / mm ² ,
kgf / mm ² or more is more preferable. The polyolefin resin film layer may have a laminated structure as described later. In this case, the compression elastic modulus of the layer is determined by the compression elastic modulus (JIS-K72
08) was multiplied by the film thickness ratio of each layer (to the total thickness of the polyolefin resin film layer).

The polyolefin resin film layer used in the present invention must further have a Vicat softening point of 145 ° C. or less [condition (2)]. In the present invention, since the polyolefin-based resin film layer is often formed as a sealant film on the surface of the laminated film, the heat-sealing property of the polyolefin-based resin film layer is important. The level of the Vicat softening point is an index of the heat resistance of the polyolefin resin. If the Vicat softening point is high, the heat resistance is excellent, and the compression modulus at the time of boiling is large. However, if the heat resistance is too high, the heat sealing property is deteriorated, so that the Vicat softening point of the polyolefin resin film layer is 145 ° C. It is determined as follows.

If the Vicat softening point exceeds 145 ° C., it is necessary to increase the heat sealing temperature or lengthen the time for pressure bonding, which is undesirable in the production process and causes poor heat sealing, adversely affecting the contents of the package. Sometimes. The preferred lower limit of the Vicat softening point is 100 ° C. If it is lower than 100 ° C., the compression elastic modulus does not satisfy (1), the gas barrier property is adversely affected, and the blocking resistance tends to be poor. When the polyolefin-based resin film layer has a laminated structure, the Vicat softening point is determined by the Vicat softening point (ASTM-D1525) of each of the laminated layers.
) Was multiplied by the film thickness ratio of each layer (to the total thickness of the polyolefin resin film layer).

The gas barrier laminate film of the present invention must satisfy the following conditions.

(3): The shrinkage (%) of the laminated film in hot water at 95 ° C. is less than 0.7 times the shrinkage (%) of the polyamide resin film layer in hot water at 95 ° C. .

This is an important condition for the gas-barrier laminated film to maintain good gas-barrier properties even after the boil treatment, and the shrinkage ratio of the laminated film in hot water at 95 ° C. [A (%)] Must be less than 0.7 times the shrinkage ratio [B (%)] of the polyamide resin film layer in hot water at 95 ° C., that is, A <0.7 × B. If A exceeds 0.7B, it indicates that the laminated film itself has shrunk following the shrinkage of the polyamide resin film layer, which is contrary to the object of the present invention. When the polyamide resin film layer shrinks, the laminated film itself shrinks, causing cracks in the inorganic deposit layer,
It is greatly damaged due to peeling or the like, and the gas barrier property is greatly reduced. For this reason, in the present invention, A <
0.7B. A laminated film satisfying this condition exhibits excellent gas barrier properties even after boiling. More preferably, A <0.6B, even more preferably A <0.5B
It is.

The polyamide resin for forming the polyamide resin film layer of the gas barrier laminate film of the present invention is not particularly limited, and any of homopolyamide, copolyamide, a mixture thereof, or a crosslinked product thereof can be used. Examples thereof include a homopolyamide, a copolyamide, a mixture thereof, and a crosslinked product thereof having an amide repeating unit represented by the following formula (I) or (II).

—CO—R ¹ —NH— (I) —CO—R ² —CONH—R ³ —NH (II) (wherein R ¹ , R ² and R ³ are straight-chain alkylene, Specific examples of preferable homopolyamides include polycaproamide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), and poly-9-aminononanoic acid (nylon 9). ), Polyundecaneamide (nylon 11), polylaurin lactam (nylon 12), polyethylene diamine adipamide (nylon 2,6), polytetramethylene adipamide (nylon 4,6), polyhexamethylene adipamide ( Nylon 6,6), polyhexamethylene sebacamide (nylon 6,10), polyhexamethylene dodecamide (nylon 6,12), polyoctamethylene Dipamide (nylon 8,6), polydecamethylene adipamide (nylon 10,6), polydecamethylene sebacamide (nylon 10,10), polydodecamethylene dodecamide (nylon 12,12), metaxylenediamine 6
Nylon (MXD6) and the like can be mentioned.

Examples of the copolyamide include caprolactam / laurin lactam copolymer, caprolactam /
Hexamethylene diammonium adipate copolymer, laurin lactam / hexamethylene diammonium adipate copolymer, hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer, ethylene diammonium adipate / hexamethylene diammonium adipate copolymer And caprolactam / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer.

In order to impart flexibility to these polyamide resins, a plasticizer such as an aromatic sulfonamide, p-hydroxybenzoic acid, or an ester may be blended, or an elastomer component having a low elastic modulus or a lactam may be added. And the like can also be blended. Elastomer components include ionomer resin, modified polyolefin resin, thermoplastic polyurethane, polyether block amide, polyester block amide, polyether ester amide elastomer, polyester elastomer, modified styrene thermoplastic elastomer, modified acrylic rubber, modified ethylene And propylene rubber. Also, if necessary, other additives, such as a plasticizer, a heat stabilizer, an ultraviolet absorber, an antioxidant, a coloring agent, a filler, an antistatic agent, an antibacterial agent, a lubricant, a blocking agent, and other resins. It is also possible to blend an appropriate amount.

The inorganic vapor deposition layer is an important layer for imparting an excellent gas barrier property to the laminated film, and does not have a problem such as polyvinylidene chloride at the time of disposal. The material of the inorganic deposit is not particularly limited, but silicon oxide and / or aluminum oxide are preferable from the viewpoint of gas barrier properties at normal temperature and gas barrier persistence after boil treatment. Is most preferably 70% by weight or less. It is also possible to laminate these oxides in layers to form an inorganic deposit layer. Other metals and metal oxides may be mixed in the inorganic vapor deposition layer in a small amount.

The preferred thickness of the inorganic vapor-deposited layer is usually in the range of 10 to 5000 °, more preferably 50 to 2000 °. If the film thickness is less than 10 °, it is difficult to obtain a sufficient gas barrier property, and if the thickness is more than 5000 °, the effect of improving the gas barrier property is saturated, and the bending resistance deteriorates and the production cost increases, which is disadvantageous. .

For the preparation of the inorganic vapor-deposited layer, a physical vapor-deposition method such as a vacuum vapor-deposition method, a sputtering method, an ion plating method, or a chemical vapor-deposition method such as a CVD method is appropriately used. Is resistance heating,
Induction heating, electron beam heating and the like can be appropriately employed. Oxygen, nitrogen, hydrogen, argon, carbon dioxide, water vapor, or the like may be introduced as a reaction gas, or a reactive deposition method using a means such as ozone addition or ion assist may be employed, or a bias may be applied to the substrate. It is also possible to change the film forming conditions such as heating and cooling of the substrate. The conditions such as the deposition material, the reaction gas, the substrate bias, and the heating / cooling can be similarly changed when employing the sputtering method or the CVD method. Before or during vapor deposition, the surface of the substrate to be vapor-deposited is subjected to a corona treatment, a flame treatment, a low-temperature plasma treatment, a glow discharge treatment, a reverse sputtering treatment, a roughening treatment, etc., to further enhance the adhesion strength of the inorganic vapor deposition layer. It is also effective. The vapor deposition is preferably performed on the polyamide resin film from the viewpoint of adhesion.

The material for the polyolefin resin film layer can be used without any particular limitation as long as it satisfies the above conditions (1) and (2). Specifically, polyethylene (linear low-density polyethylene, high-pressure low-density polyethylene, high-density polyethylene, etc.), polypropylene,
Homopolymers such as polybutene-1, poly-4-methylpentene-1, ethylene / propylene copolymer, ethylene / butene-1 copolymer, ethylene / 4-methyl-pentene-1 copolymer, ethylene / decene- 1 copolymer, propylene / 4-methyl-pentene-1 copolymer, propylene / butene-1 copolymer, decene / 4-methyl-pentene-1 copolymer, ethylene / propylene / butene-1 copolymer And the like.

As the linear low-density polyethylene, ethylene and preferably at least one kind of 0.2 to 20 mol%, more preferably 1 to 10 mol% of α-olefin having 3 to 10 carbon atoms, Those copolymerized in a liquid phase or a gas phase can be used, and specific examples of the α-olefin include propylene, butene-1, pentene-1, hexene-1, octene-1, nonene-1, decene-1, 4-methylpentene-1, 4-methylhexene-1, 4,4-dimethylpentene-1 and the like. Among linear low-density polyethylenes, the density is 0.900 to 0.960 g / cm ^2.
Is preferably used. A more preferred density is
0.910 to 0.950 g / cm ² .

The method for producing the polyolefin resin is not particularly limited, and may be any of a gas phase method and a liquid phase method. The catalyst may be a Ziegler-Natta catalyst, vanadium oxytrichloride, vanadium tetrachloride, organoaluminum, metallocene catalyst, or a mixture thereof. The preferred MI (melt index) range of the polyolefin resin is as follows:
1 to 15 g / 10 minutes (23 according to JIS K7210)
At 0 ° C). As the polyolefin-based resin, those deodorized by, for example, a reduced pressure treatment are preferably used.

The above-mentioned polyolefin-based resin may contain various additives which are usually added to the polyolefin composition as long as the heat-sealing property and the surface protection effect are not impaired.
For example, plasticizers, heat stabilizers, UV absorbers, antioxidants,
An appropriate amount of a coloring agent, a filler, an antistatic agent, an antibacterial agent, a lubricant, an antiblocking agent, and the like may be used as long as the effects of the present invention are not impaired. It is preferable to use spherical fine particles as the anti-blocking material. The spherical fine particles have an effect of balancing the transparency, slipperiness and blocking resistance of the film.

In the present invention, since the polyolefin-based resin film layer is often formed as a sealant film on the surface of a laminated film, heat sealability, slipperiness, blocking resistance,
Laminating properties, gas barrier properties, impact resistance, surface protection properties,
It is preferable to have excellent mechanical properties and the like. Therefore, the polyolefin-based resin film layer may have a single-layer structure, but it is difficult to satisfy all of the above properties with a single layer. Therefore, the respective functions are shared and two or more layers, more preferably three or more layers are laminated. It is preferable to have a structure.

The polymer constituting each layer in the laminate structure may be a copolymer, a modified product, a blend of the same polymer, or a laminate of different polymers. It is desired that the Vicat softening point of each layer is 100 ° C. or higher. If the temperature is lower than 100 ° C., it is difficult to obtain excellent gas barrier properties. In addition, since heat resistance is inferior, inconveniences such as fusion of portions other than the seal portion occur during the bag making and content filling steps. Of course, the Vicat softening points of the respective layers are preferably different from each other, and the layer having the lowest Vicat softening point may be positioned as the outermost layer as the heat seal layer.

The higher Vicat softening point is located on the side of the inorganic resin vapor deposition layer of the polyamide resin film layer for lamination. Since the higher the Vicat softening point, the better the mechanical properties such as the compression modulus and the heat resistance, the preferred Vicat softening point of the layer for lamination is 120 ° C. or higher, more preferably 140 ° C. or higher. However, a combination of resins to be laminated should be selected so that the Vicat softening point of the entire polyolefin resin film layer having a laminated structure does not exceed 145 ° C. specified in the condition (2).

In order to produce a laminated polyolefin resin film as described above, a coextrusion molding method is preferable.
For example, an inflation molding method using a circular die, T
T-die molding using a die can be employed. When performing T-die molding, the draft rate is 1 to 10, and the resin temperature is 190.
It is preferable to set the temperature to 300 ° C. The thickness is appropriately set according to the total thickness of the gas barrier laminate film,
As the polyolefin resin film, usually 5 to 15
0 μm, more usually in the range of 15 to 80 μm.

In the gas barrier laminate film of the present invention, the oxygen permeability after boiling in hot water is selected as a measure for achieving gas barrier properties, and this value is 15 cc / m ² · at.
A preferable condition is that it is not more than m · day. In particular, when the contents to be packaged are foods, the foods undergo a chemical reaction such as oxidation due to contact with oxygen, and the quality deteriorates.
If the laminated film is 15 cc / m ² · atm · day or less after the boil treatment, it has excellent oxygen blocking ability, and the storage stability of the package contents is remarkably improved. Fifteen
Those exceeding cc / m ² · atm · day are recommended for use in packages other than those requiring boil processing. A more preferable oxygen permeability is 10 cc / m ² · atm · day or less, further preferably 6 cc / m ² · atm · day or less.

The laminated structure of the gas-barrier laminated film of the present invention is not particularly limited. However, as described above, the polyolefin-based resin film layer is suitable as a sealant film. It is preferable that the layers are laminated in the order of layer-polyamide resin film layer. Of course, an intervening layer may be provided between each layer.

The present invention provides a gas-barrier laminated film excellent in heat sealability by providing a specific polyolefin-based resin film layer. Therefore, it is determined that the heat sealing start temperature is 135 ° C. or less as a preferable condition. The heat-sealing start temperature means that the gas-barrier laminated films are separated at various temperatures by 2 kgf / c.
After heat-sealing at m ² for 1 second, a 90 ° peel test is performed, and this is the heat-sealing temperature when the peel strength becomes 500 g / 15 mm or more. The heat-sealing start temperature is a condition that affects the heat-sealing property and the strength after bag making. If the heat-sealing start temperature exceeds 135 ° C., the temperature required for heat sealing becomes higher or the crimping time becomes longer, resulting in production. This is not preferred because the properties are reduced and the strength after bag making is reduced. A more preferable heat sealing start temperature is 120 ° C. or lower.

It is also a preferable condition that the blocking resistance measured according to ASTM-D1893-67 is 10 g / 20 mm or less. If the blocking resistance exceeds 10 g / 20 mm, inconvenience tends to occur in winding in the production process. A more preferred value of the blocking resistance is 7 g / 20 mm or less.

The gas barrier laminate film of the present invention is basically produced by laminating a polyolefin resin film layer on a polyamide resin film layer on which an inorganic vapor deposition layer is formed. In order to increase the interlayer adhesion of the laminated film and improve the gas barrier property retention and mechanical strength, the polyamide-based resin film layer has an anchor coat layer between the inorganic vapor-deposited layers, the inorganic vapor-deposited layer and the polyolefin-based resin. An adhesive layer may be interposed between the film layers.

The anchor coat layer can be formed by applying an anchor coat agent. Reactive polyester resin, oil-modified alkyd resin, urethane alkyd resin, melamine alkyd resin, epoxy cured acrylic resin, epoxy resin (amines, carboxyl group-terminated polyesters) , Phenols, isocyanates), isocyanate resins (cured by amines, ureas, carboxylic acids), urethane-polyester resins, polyurethane resins, phenolic resins, polyester resins, polyamide resins, reactive acrylic resins, vinyl chloride A resin or the like is a specific example of the anchor coating agent. Any form of a solution system, an aqueous dispersion system, and an aqueous solution system can be used. Also,
An inorganic coating agent such as a silane coupling agent may be used.

The method of forming the anchor coat layer may be any of an in-line method of applying the resin film at the time of production, and an off-line method of applying the resin film in a separate step from the production of the resin film. Coating, reverse coating, roll brushing, spray coating, air knife coating, gravure coating, impregnation (dipping), curtain coating, and the like can be used.

The formation of the anchor coat layer increases the chemical bonding force between the base film and the inorganic vapor deposition, thereby improving the adhesion. The preferred thickness of the anchor coat layer is 0.01 to 10 μm. When the thickness is less than 0.01 μm, the effect of improving the adhesion by coating is not exhibited, and when the thickness exceeds 10 μm, the improvement effect is saturated, and inconvenience may occur in the coating process such as formation of pinholes. A more preferred thickness is from 0.02 to 5 μm. As the adhesive layer that can be interposed between the inorganic vapor deposition layer and the polyolefin resin film layer, an adhesive resin having a glass transition temperature of about −10 to 40 ° C. is preferably used. For example, polyurethane resin,
Known adhesives such as polyester resin, epoxy resin, vinyl chloride resin, vinyl acetate resin, polyethylene resin, polypropylene resin, and melamine resin can be used. In order to enhance the adhesive strength, an adhesive having good compatibility may be mixed, and a carboxyl group, (meth) acrylic acid having an acid anhydride group or an ester thereof, such as an epoxy compound having a glycidyl group or a glycidyl ether group, ,
A so-called curing agent having a functional group such as an oxazolinyl group, an isocyanate group, an amino group, or a hydroxyl group can be used in addition to the adhesive. As a method of applying the adhesive, a dry lamination method, a melt extrusion lamination, a co-extrusion lamination, or the like can be adopted in addition to the method (wet lamination) described for the anchor coat layer.

The gas barrier laminate film for boil treatment of the present invention makes use of its excellent gas barrier properties and gas barrier persistence after boil treatment, and is used as a food packaging material for miso, pickles, side dishes, baby food, tsukudani, konjac, chikuwa, Kamaboko, fishery products, meatballs, hamburgers,
It can be used for Genghis Khan, ham, sausage and other processed meat products. There is no particular limitation on the form of use of the packaging material, and it can be widely used as bags, lids, cups, tubes, standing pouches, and the like.

[0051]

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. Of course, the present invention can be embodied with modifications, all of which are included in the technical scope of the present invention. The methods for evaluating various performances employed in the following examples are as follows.

[Compression modulus] The compression modulus of the polyolefin resin film layer when boiled (hot water at 95 ° C.) [kg
f / mm ² ] was measured using an S-STAM measuring device manufactured by Rigaku Corporation according to JIS-K7208. When there were two or more polyolefin-based resin film layers, the sum was obtained by multiplying the compression elastic modulus of each layer by the film thickness ratio of each layer (to the total thickness of the polyolefin-based resin film layer).

[Vicat Softening Point] The Vicat softening point of the polyolefin resin film layer was determined according to ASTM-D1525.
It measured according to. When the number of the polyolefin resin film layers was two or more, the sum was obtained by multiplying the Vicat softening point of each layer by the film thickness ratio of each layer (to the total thickness of the polyolefin resin film layer).

[Shrinkage] The target film was 200 mm in diameter.
And immersed in hot water at 95 ° C. for 30 minutes, and the dimensional changes after immersion were determined by vertical (0 °), horizontal (90 °),
It checked about 0 degree, 45 degree, and 60 degree, and made the average value the contraction rate.

[Heat Seal Initiation Temperature] The gas barrier laminated films were heat-sealed at various temperatures at 2 kgf / cm ² for 1 second, and then subjected to a 90 ° peel test.
The heat sealing temperature when the peel strength was 500 g / 15 mm or more was defined as the heat sealing start temperature.

[Blocking Resistance] The gas barrier laminate film was measured according to ASTM-D1893-67.

[Oxygen Permeability] Oxygen permeability measuring device (“O
X-TRAN 10 / 50A "Modern Cont
rols) at a humidity of 0% and a temperature of 25 ° C.
The measurement was performed for “normal state” and after immersion in hot water of 95 ° C. for 30 minutes (“after immersion in hot water”).

[Water Vapor Permeability] A water vapor permeability measuring apparatus (“PERMATRAN” Modern Control)
(manufactured by Iss Co., Ltd.) at 0% humidity and a temperature of 25 ° C. for “normal” and after immersion in hot water of 95 ° C. for 30 minutes (“after immersion in hot water”).

Example 1 A film was formed using nylon-6 containing ε-caprolactam as a main raw material as a polyamide resin. Corona treatment was performed during the film forming process. The shrinkage of this film after heating at 120 ° C. for 5 minutes is 1.5% in the vertical direction and 1.0% in the horizontal direction, and the shrinkage stress per unit sectional area is 1.2 kgf / m.
m ² .

The obtained corona-treated nylon-6 film was set on an unwinding roll of a vapor deposition device. Then, while heating and evaporating silicon dioxide and aluminum oxide as an evaporation material using an electron beam heating type vacuum evaporation apparatus,
A nylon-6 film was run over the deposition source to form an inorganic deposition layer. The thickness of the inorganic deposit layer is 200
Å, the content of aluminum oxide was 40% by weight.

A two-pack polyurethane adhesive (“A310 / A10” manufactured by Takeda Pharmaceutical Co., Ltd., Tg :−)
12 ° C.) at 5 g / m ² and a polyolefin-based film (three layers: 55 μm) is dry-laminated thereon.
A gas barrier laminated film was obtained.

Examples 2 to 5, Comparative Examples 1 to 5 Laminated films having the structures shown in Table 1 were dry-laminated in the same manner as in Example 1.

Table 2 shows the properties of the polyolefin resin film layers obtained in the above Examples and Comparative Examples, and Table 3 shows the performance of each gas barrier laminate film.

The materials and abbreviations of each layer described in Table 1 are as follows.

(1) Polyamide resin film layer Polycaproamide: Nylon-6 (2) Inorganic deposit layer Silicon dioxide + aluminum oxide: SiO ₂ + Al ₂ O ₃ (3) Polyolefin resin film layer High density polyethylene: HDPE High pressure method low density polyethylene: LDPE Linear low density polyethylene: L-LDPE Ethylene-propylene random copolymer: Et-Pr
(R) Ethylene-propylene block copolymer: Et-Pr
(B) Ethylene-propylene-butene ternary random copolymer: Et-Pr-Bu biaxially oriented polypropylene: OPP

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

[0069]

The present invention is constituted as described above and exhibits excellent gas barrier properties at room temperature, and does not cause a decrease in gas barrier properties even after boiling or retorting, and is practically sufficient. Due to its strength and heat-sealing properties, it can be widely used as a packaging film for various foods, or as a packaging material for medical products that require aseptic handling or electronic components that require rust prevention. Can be.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideyuki Mitamura 344 Maebata, Kizu, Ozu, Inuyama, Aichi Prefecture Inside the Inuyama Plant of Toyo Boseki Co., Ltd. (72) Inventor Yozo Yamada 2-1-1 Katata, Otsu-shi, Shiga Pref., Toyo Spinning Co., Ltd. (56) References JP-A-6-190961 (JP, A) JP-A Heihei 7-276571 (JP, A) JP-A-3-24953 (JP, A) JP-A-2-69237 (JP, A) JP-A 64-1535 (JP, A) Japanese Utility Model Application Laid-open No. 57-11031 (JP, A) U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (6)

(57) [Claims] 1. A laminated film having at least three layers of a polyamide resin film layer, an inorganic vapor deposition layer and a polyolefin resin film layer, wherein the laminated film satisfies the following conditions (1) to (3). Boil
Gas barrier laminated film for use . (1) The compression elastic modulus in hot water at 95 ° C per unit sectional area of the polyolefin resin film layer is 8 kgf.
/ Mm ² or more. (2) The Vicat softening point of the polyolefin resin film layer is 145 ° C. or less. (3) The shrinkage (%) of the laminated film in hot water at 95 ° C. is less than 0.7 times the shrinkage (%) of the polyamide resin film layer in hot water at 95 ° C. 2. The polyolefin-based resin film layer is formed by laminating two or more polyolefin-based resin film layers, and each of the film layers has a Vicat softening point of 100 ° C. or higher. Described in
Gas barrier laminated film for boil treatment . 3. Oxygen permeability after boiling in hot water is 15
The gas-barrier laminated film for boil treatment according to claim 1 or 2, which has a cc / m ² · atm · day or less. 4. The method according to claim 1, wherein the gas-barrier laminated films are 2 k
After heat-sealing at gf / cm ² for 1 second, a 90 ° peel test was performed. When the heat-sealing temperature when the peel strength was 500 g / 15 mm or more was taken as the heat-sealing start temperature, the heat-sealing start temperature was 135. The gas-barrier laminated film for boil treatment according to any one of claims 1 to 3, which is at most 0C. 5. The gas barrier laminated film for boil treatment according to claim 1, wherein the blocking resistance measured according to ASTDM-D1893-67 is 10 g / 20 mm or less. 6. The gas barrier laminate film for boil treatment according to claim 1, wherein the polyolefin resin film layer is present on the outermost layer .