JP3307230B2 - Gas barrier laminate film or sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent 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, and excellent handling properties. It relates to a laminated resin film or sheet.

[0002]

2. Description of the Related Art In recent years, food packaging has been drastically changed due to changes in food distribution and eating habits, and the required characteristics of packaging films and sheets (hereinafter referred to as films) have become increasingly severe. Is coming.

[0003] Deterioration in product quality due to temperature changes, moisture, oxygen, ultraviolet rays, and microorganisms such as bacteria and mold in the distribution and sales process is a serious problem not only in terms of sales but also in terms of food hygiene. . 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 these circumstances, there is an increasing demand for a packaging film that has a low gas and moisture permeability and does not cause deterioration in food quality even by freezing, boiling, or the like.

That is, in the packaging of fish meat, animal meat, shellfish and the like, it is important to suppress the oxidation and deterioration of proteins and fats and oils, and to maintain taste and freshness. For this purpose, packaging materials having good gas barrier properties are required. It is desired to block the permeation of air by using a. Moreover, if wrapped in a gas barrier film,
Since the aroma of the contents is retained and the permeation of water is prevented, the moisture absorption of dried products is suppressed, and the deterioration and solidification of water-containing products due to evaporation of water are suppressed. It can be held for a long time.

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 of 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 for medical products that need to be handled under aseptic conditions and packaging films for electronic components that require rust prevention. It is extremely important.

As a film having excellent gas barrier properties,
Known are those in which a metal such as aluminum is laminated on a plastic film, those coated with a vinylidene chloride resin 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 silicon oxide, aluminum oxide, or the like is laminated is also known.

[0007]

The following problems have been pointed out in the conventional gas barrier films as described above. 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 it does not transmit microwaves. Processing by microwave oven is not possible.

Further, those coated with a gas barrier layer of a vinylidene chloride resin, an 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 significantly deteriorated particularly during high-temperature treatment.
In addition, for vinylidene chloride, there is a problem of air pollution due to generation of chlorine gas at the time of incineration.

On the other hand, as a gas barrier film whose contents can be seen and which can be applied to a microwave oven, Japanese Patent Publication No. 51-48 (1971) is disclosed.
No. 551 discloses that the surface of a synthetic resin film is made of SiO _x
A gas barrier film on which (for example, SiO ₂ ) has been deposited has been proposed. However, a SiO _x (x = 1.3 to 1.8) oxide film having a good gas barrier property has a slightly brown color and transparency. Is inadequate.

An oxide film mainly composed of aluminum oxide as disclosed in Japanese Patent Application Laid-Open No. Sho 62-101428 is known as one having sufficient transparency. In addition, the resin has poor flex resistance and does not withstand the Gelboflex test (a test method in which a cylindrical test piece is forcibly bent to evaluate the flexibility).

That is, a laminated film having an inorganic film such as silica or alumina as a gas barrier layer has a problem in film strength, and also has a problem in that the gas barrier property is deteriorated by a boiling treatment or a retort treatment. An inorganic vapor-deposited layer such as silica or alumina is formed of a polyester film (PE
T) is often deposited. For example, in the case of a laminated structure such as PET / deposited layer / adhesive layer / stretched nylon (ONY) / adhesive layer / unstretched polypropylene (CPP), boiling treatment or retort is caused by shrinkage of nylon. Since the gas barrier property is deteriorated due to the shrinkage of nylon during the treatment, it is customary to eliminate the lamination of nylon and make a laminated structure of PET / deposited layer / adhesive layer / PET / adhesive layer / unstretched polypropylene (CPP). ing. However, in the laminated film having the above-described structure in which the lamination of nylon is eliminated, insufficient strength at the time of dropping becomes a serious problem.

Furthermore, the shrinkage rate of a stretched nylon (Japanese Patent Publication No. Hei 7-12649) used as a vapor deposition base material and a nylon (Japanese Patent Laid-Open Publication No. Hei 7-276571) as a laminate is reduced during high-temperature treatment. Although those with strength have been proposed, there is a problem that the manufacturing process of nylon and the process of transport and storage are complicated,
Not suitable for practical use. Further, nylon having a reduced shrinkage rate during high-temperature treatment (Japanese Patent Publication No.
(The sum of the absolute values of the dimensional change rates in the vertical and horizontal directions by heat treatment for 5 minutes is specified to be 2% or less.) Notably, good gas barrier properties cannot be maintained.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 7-276571, it is necessary to laminate a low-shrinkage nylon layer separately from the vapor-deposited base material layer, which complicates the process, leading to an increase in manufacturing cost and heat. There is also a problem that the mechanical strength of the polyamide film decreases during the fixing operation.

Further, no consideration is given to the shrinkage rate of the vapor deposition base material and the entire laminated component, and a laminated film capable of maintaining a sufficient gas barrier property even after boiling treatment is not commercially available.

The present invention has been made in view of such circumstances, and has an object to provide excellent strength characteristics and gas barrier properties, without impairing the excellent gas barrier properties even after boiling treatment, and at the same time, by heat treatment. An object of the present invention is to provide a gas barrier laminated film that can be suitably used for sealing.

[0016]

The gas-barrier laminated film or sheet according to the present invention which can solve the above-mentioned problems comprises an inorganic vapor-deposited layer on one side or both sides of a base layer composed of a polyamide film. A laminated film or sheet on which a gas barrier layer is formed and further a heat seal layer is formed, wherein the polyamide film constituting the base layer has a shrinkage stress in each direction at 170 ° C. of 950 gf / mm ² or less, and The shrinkage rate in each direction when heat-treated at 170 ° C. for 10 minutes is 4.0% or less, and the shrinkage rate in each direction when the laminated film or sheet is boiled at 95 ° C. for 30 minutes is 2%. 0.5% or less, and the adhesion strength between the base layer and the gas barrier layer after the boiling treatment is 100 g / 15 m.
By setting it to m or more, there is a characteristic in that excellent gas barrier properties are maintained even after heat treatment and boiling treatment.

In the present invention, in addition to the above properties, providing an adhesion improving layer as an undercoat layer between the base layer and the gas barrier layer to enhance interlayer adhesion between the two layers is intended to further improve gas barrier properties. Becomes effective.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the gas-barrier laminated film of the present invention comprises a polyamide resin film as a base layer, and a gas barrier layer composed of an inorganic vapor-deposited layer and a heat seal layer formed on one or both sides thereof. (1) The polyamide film constituting the base layer has a shrinkage stress in each direction at 170 ° C. of 950 gf / mm ² or less, and
The shrinkage in each direction when heat-treated at 0 ° C. for 10 minutes has a property of not more than 4.0%, and preferably, in addition to such properties, (2) the laminated film or sheet is heated to 95 ° C.
The shrinkage in each direction after boiling for 30 minutes at 2.5 ° C is 2.5% or less, or (3) 30% at 95 ° C.
It has the characteristic that the adhesion strength between the base layer and the gas barrier layer after boiling for one minute is 100 g / 15 mm or more.

Hereinafter, each of the laminated components specified in the present invention will be described in detail, and the reason for defining the above characteristics will be described in detail. In the gas barrier laminate film of the present invention, the polyamide-based film constitutes the base layer of the laminate film, and functions as a support layer of the inorganic vapor-deposited layer constituting the gas barrier layer. To ensure gas barrier properties, the shrinkage stress in each direction at 170 ° C. is 9
50 gf / mm ² or less (preferably 600 gf / mm ²
Or less, more preferably 400 gf / mm ² or less, more preferably 200 gf / mm ² or less), yet 170 ° C.
The shrinkage in each direction when heat-treated for 10 minutes at a temperature of not more than 4.0% (more preferably not more than 2.0%, more preferably not more than 0.7%).

According to the results of various studies conducted by the present inventors, it has been found that an inorganic vapor-deposited layer formed on one side or both sides of the polyamide film can effectively exhibit its properties as a gas barrier layer. It is necessary not to apply an undesired deformation force or a force in a peeling direction to the inorganic vapor-deposited layer even at the time of the boiling treatment, and when the contraction stress per unit cross-sectional area is too large, the inorganic vapor-deposited layer is shrunk at the time of the boiling treatment. It is thought to cause deformation stress in the layer and cause the inorganic vapor deposition layer to break or peel off. However, as will be apparent from the following examples, the contraction stress in each direction of the polyamide-based film was 950 gf / m2.
suppresses the m ² or less, do it each direction shrinkage when heat-treated for 10 minutes at 170 ° C. both be suppressed to 4.0% or less, destruction and peeling of the above such inorganic vapor deposition layer by boiling treatment It does not occur, and it is considered that excellent gas barrier properties are stably maintained.

The material of the polyamide film used in the present invention is not particularly limited as long as it satisfies the above-mentioned shrinkage characteristics, and any of homopolyamide, copolyamide, a mixture thereof, or a crosslinked product thereof can be used. For example, a homopolyamide, a copolyamide, a mixture thereof, or a crosslinked product thereof having an amide repeating unit represented by the following formula (1) or (2) can be used. —CO—R ₁ —NH— (1) —CO—R ₂ —CONH—R ₃ —NH (2) (wherein R ₁ , R ₂ , and R ₃ are straight-chain alkylene, aromatic ring Or an aliphatic alkyl group)

Specific examples of preferred homopolyamides include polycaproamide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-9-aminononanoic acid (nylon 9), and polyundecaneamide (nylon 1).
1), polylaurin lactam (nylon 12), polyethylene diamine adipamide (nylon 2,6), polytetramethylene adipamide (nylon 4,6), polyhexamethylene adipamide (nylon 6,6), poly Hexamethylene sebacamide (nylon 6,10), polyhexamethylene dodecamide (nylon 6,12), polyoctamethylene adipamide (nylon 8,6), polydecamethylene adipamide (nylon 10,6), Polydecamethylene sebacamide (nylon 10, 10), polydodecamethylene dodecamide (nylon 12, 12), metaxylene diamine-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.

These polyamide resins may be blended with a plasticizer such as aromatic sulfonamides, p-hydroxybenzoic acid, esters, etc., for imparting flexibility, or may contain a low elastic modulus elastomer component or lactam. It is also possible to mix. Examples of the elastomer component include an ionomer resin, a modified polyolefin resin, a thermoplastic polyurethane, a polyether block amide, a polyester block amide, a polyether ester amide elastomer, a polyester elastomer, a modified styrene thermoplastic elastomer, a modified acrylic rubber, and a modified acrylic rubber. And ethylene propylene rubber.

The polyamide film constituting the base layer
The above-mentioned required characteristics, ie, “shrinkage in each direction”
All stresses are 950gf / mm^Two Below ”,“ 170 ° C
Shrinkage in each direction when heat-treated for 10 minutes at
For example, in order to provide characteristics such as “4.0% or less”,
A moderate temperature is applied to a qualitatively unoriented polyamide resin sheet.
And a method of performing biaxial stretching at a stretching ratio.
Is [Tg (glass transition temperature) +10] ° C or higher [Tc
(Crystallization temperature) +20] ° C.
After stretching 5 to 4.0 times, successively at different temperatures
A method of successively performing two-stage transverse stretching is exemplified. Two-stage horizontal rolling
In elongation, it is not less than (Tc + 20) ° C and not more than (Tc + 70) ° C.
The pre-stage transverse stretching is performed at a temperature of 1.1 to 2.9 times, and then
(Tc + 70) ° C or higher [Tm (melting temperature) -30] ° C or lower
At a lower temperature, the total transverse stretching ratio is about 3.0 to 4.5 times.
Perform horizontal stretching in the subsequent stage as follows, and then use a tenter
At (Tm-30) ° C or higher and (Tm-10) ° C or lower
Adopt a method of performing 0-10% relaxation heat treatment in the lateral direction
For example, shrinkage in each direction when heat treated at 170 ° C for 10 minutes
Rate can be suppressed to 4.0% or less, and
After axial stretching, do not relax in the machine direction using multi-stage rolls.
Heat treatment with humidified gas of rag and / or 60-100 ° C
Then, the shrinkage stress in each direction at 170 ° C. is 9
50gf / mm ^Two It can be:

In the above-mentioned resin constituting the base layer, other additives such as plasticizers, heat stabilizers, ultraviolet absorbers, antioxidants, coloring agents, fillers, antistatic agents, antibacterial agents, It is also possible to blend an appropriate amount of a lubricant, an antiblocking agent, another resin and the like. On one side or both sides of the polyamide-based film constituting the base layer, an inorganic vapor-deposited layer constituting a gas barrier layer is formed.Before or during the vapor deposition, the surface of the polyamide-based film is subjected to corona treatment, It is also effective to apply a flame treatment, a low-temperature plasma treatment, a glow discharge treatment, a reverse sputtering treatment, a surface roughening treatment, etc. to increase the adhesion to the deposited layer.

That is, it is extremely effective to enhance the adhesion between the base layer and the inorganic vapor-deposited layer in order for the inorganic vapor-deposited layer to exhibit sufficient gas barrier properties. It is effective to perform an adhesion improving treatment on the vapor deposition surface side, but as another means, it is also extremely effective to form an anchor coat layer in order to increase the adhesion of the vapor deposition layer.

Preferred resins used as such an anchor coat layer include a reactive polyester resin, an oil-modified alkyd resin, a urethane-modified alkyd resin, a melamine-modified alkyd resin, an epoxy-modified acrylic resin, and an epoxy resin (an amine as a curing agent). , Carboxyl-terminated polyesters, phenols, isocyanates, etc.), isocyanate resins (amines as curing agents,
Urea, carboxylic acid, etc.), urethane-polyester resin, polyurethane resin, phenol resin, polyester resin, polyamide resin, reactive acrylic resin, vinyl chloride resin and the like. It can be used as a latex, an aqueous liquid (aqueous solution or aqueous dispersion).

As a method for forming the anchor coat layer,
Any of an in-line method in which a polyamide-based film is applied and an off-line method in which a polyamide-based film is applied in a separate step can be adopted. For the coating, any known method such as a roll coating method, a reverse coating method, a roll brushing method, a spray coating method, an air knife coating method, a gravure coating method, an impregnation method, a curtain coating method, or the like is arbitrarily selected and employed. be able to.

The anchor coat layer is subjected to a corona treatment, a flame treatment, a low-temperature plasma treatment, a glow discharge treatment, a reverse sputtering treatment, a surface roughening treatment or the like before or during the vapor deposition.
It is also effective to further increase the adhesion to the inorganic vapor deposition layer.

The inorganic vapor-deposited layer is a constituent material that is indispensable for imparting gas barrier properties to the laminated film, and its kind is not particularly limited. Al, Si, Ti, Zn, Zr, M
metals such as g, Sn, Cu, Fe and oxides of these metals;
Nitride, fluoride, sulfide, etc., more specifically, Si
O _x (x = 1.0-2.0), alumina, magnesia,
Examples thereof include zinc sulfide, titania, zirconia, and cerium oxide. These may be formed as a mixed vapor-deposited layer of two or more types or a multi-layered vapor-deposited layer as necessary.

The preferred thickness of the above-mentioned inorganic vapor-deposited layer is usually from 10 to 5,000, more preferably from 50 to 2,000.
If the thickness is less than 10 mm, it is difficult to obtain a sufficient gas barrier property, and if the thickness is more than 5000 mm, the gas barrier property cannot be further improved. It is disadvantageous in terms of cost.

For the formation of the inorganic vapor deposition layer, a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method or an ion plating method, or a chemical vapor deposition method such as a PECVD method is appropriately selected and used. Preferred deposition materials when employing the vacuum deposition method include metals such as aluminum, silicon, titanium, magnesium, zirconium, cerium, and zinc,
Alternatively, SiO _x (x = 1.0 to 2.0), alumina,
Compounds such as magnesia, zinc sulfide, titania, and zirconia, and mixtures thereof are used. As a heating method, resistance heating, induction heating, electron beam heating, or the like can be used. Further, as the reactive gas, oxygen, nitrogen, hydrogen, argon, carbon dioxide gas, water vapor, or the like may be introduced, or reactive vapor deposition using means such as ozone addition and ion assist may be used. Further, a bias may be applied to the substrate, or film forming conditions such as heating and cooling of the substrate may be changed. The above-mentioned deposition material, reaction gas, substrate bias, heating / cooling, and the like can be similarly changed in film forming conditions when a sputtering method or a CVD method is adopted.

Before or during the vapor deposition, the surface of the vapor-deposited substrate 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.
As described above, it is effective to enhance the adhesion of the deposited film.

In the gas barrier laminate film of the present invention, the heat seal layer protects the inorganic vapor-deposited layer constituting the gas barrier layer and acts as a thermal adhesive layer at the time of bag making, and the type thereof is not particularly limited. Preferred examples include films made of olefin resins such as polyethylene and ethylene copolymers, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polypropylene and propylene copolymers; polyvinyl chloride and copolymers thereof. A film composed of a vinylidene chloride resin such as vinylidene chloride-vinyl chloride copolymer; a film composed of a polyester resin such as polyethylene terephthalate; a fluororesin such as polyvinyl difluoride the film, The, like coated film coated with resin different further sealant base film of these films.

The heat seal layer may be a modified product or a blend of the above resin, or may be an unstretched product of a film made of the constituent materials, or a uniaxially or biaxially stretched film. Needless to say, a single-layer structure or a multi-layer structure of the same or different materials may be used. Specifically, for example, in order to enhance the laminating property and the heat sealing property, it is combined with a resin having a glass transition temperature (Tg) or a melting point lower than that of the thermoplastic resin serving as the base of the heat sealing layer, or the heat resistance is increased. Tg
It can also be combined with a resin having a high melting point.

The heat seal layer is laminated on the inorganic vapor-deposited layer constituting the gas barrier layer. In the lamination, for example, a polyurethane resin, an acrylic resin, a polyester resin, An arbitrary adhesive such as an epoxy resin, a vinyl chloride resin, a vinyl acetate resin, a polyethylene resin, a polypropylene resin, and a melamine resin can be used.
These resins may be used as a mixture of two or more kinds as necessary to enhance the adhesive strength. In addition, for example, compounds having a carboxyl group or an acid anhydride group as a functional group, (meth) acrylic acid or (meth) It is also effective to use an appropriate amount of a compound having an acrylate ester skeleton, an epoxy compound containing a glycidyl group or a glycidyl ether group, or a compound having an oxazoline group, an isocyanate group, an amino group, a hydroxyl group, or the like.

These adhesive resins can be formed by a so-called dry lamination method, a wet lamination method using an emulsion, a melt extrusion lamination method, a coextrusion lamination method, or the like.

When the heat seal layer is formed by coating, a coating agent is used. Suitable coating agents in this case include vinylidene chloride resins such as vinylidene chloride-vinyl chloride copolymer and polyester resins such as polyethylene terephthalate. And a solution or emulsion of a fluororesin such as polyvinyl difluoride. Among them, a latex of a vinylidene chloride resin and a solution in which the vinylidene chloride resin is dissolved in a solvent such as tetrahydrofuran are preferable.

When a vinylidene chloride-based resin is applied, an adhesion promoter such as an isocyanate-based, polyethyleneimine-based, or organic titanium-based adhesive, or a polyurethane-based or polyester-based adhesive can be applied between the resin and the coating base.

In the gas barrier laminate film of the present invention, a gas barrier layer comprising an inorganic vapor-deposited layer is formed on one or both sides of the polyamide film constituting the base layer as described above, with or without an anchor coat layer interposed therebetween. Further, it has a laminated structure in which a heat seal layer is formed thereon, and its feature is that the lower limit value of the shrinkage stress per unit area in each direction at 170 ° C. of the polyamide-based film constituting the base layer as described above. Stipulate and 170
The upper limit value of the shrinkage rate in each direction when heat-treated at 10 ° C. for 10 minutes is specified. Preferably, in addition to the properties of the base film, the heat shrinkage properties of the laminated film as a whole are 30 ° C. at 95 ° C. The shrinkage rate in each direction when the boiling treatment is performed for 4.0 minutes is 4.0% or less (more preferably 1.%).
5% or less, more preferably 0.7% or less), and the adhesion strength between the base layer and the inorganic vapor-deposited layer after further performing the boiling treatment at 95 ° C. for 30 minutes is preferably 100 g / 15 mm or more. By adding the properties, the performance as a gas barrier laminated film can be further improved.

That is, in the present invention, as described above, it is an object of the present invention to maintain excellent gas barrier performance even after the boiling treatment. A large compressive force acts on the thin, small heat-shrinkable inorganic vapor-deposited layer of the film constituent layers, which causes the vapor-deposited layer to be damaged or peeled off, and the adhesion strength between the base layer and the inorganic vapor-deposited layer after the boiling treatment is insufficient. In such a case, the inorganic vapor-deposited layer is also likely to be peeled off, leading to deterioration of gas barrier properties. Therefore, in order to suppress the deterioration of the gas barrier property due to such factors, it is effective to add the above-described characteristics.

The above-mentioned shrinkage stress and shrinkage mean the shrinkage stress and shrinkage in the vertical, horizontal and diagonal directions of the entire laminated film, and all of them need to satisfy the above values. When the shrinkage stress or shrinkage in any one direction exceeds the above-mentioned values, the gas barrier property is significantly deteriorated by the boiling treatment.

Means for ensuring the above-mentioned shrinkage stress and shrinkage rate of the entire laminated film or for enhancing the interlayer adhesion strength between the base layer and the gas barrier layer or between the gas barrier layer and the heat seal layer are not particularly limited. The purpose can be easily achieved by appropriately combining various means.

(1) As a material for a polyamide film,
Select a moisture-resistant material that has a small shrinkage rate under heating conditions.
Specifically, a substantially unoriented polyamide-based resin sheet is longitudinally stretched in the longitudinal direction by 2.5 to 4.0 times at a temperature of (Tg + 10) ° C or more and (Tc + 20) ° C or less, and subsequently in the transverse direction. This is a method in which two-stage transverse stretching is performed continuously at different temperatures. In the two-stage transverse stretching, (Tc + 20) ° C. or more (Tc + 7
0) The pre-stage horizontal stretching is performed 1.1 to 2.9 times at a temperature of not more than 0 ° C, and then (Tc + 70) ° C or more [Tm (melting temperature)
−30] ° C. and a total transverse stretching ratio of 3.0 to 3.0 ° C.
Perform horizontal stretching in the subsequent stage so that it becomes about 4.5 times, and then
Using a tenter (Tm-30) ° C or higher (Tm-10)
A method of suppressing the maximum shrinkage of the base layer film by performing 0 to 10% relaxation heat treatment in the transverse direction at a temperature of not more than ℃.

(2) As the polyamide-based film material, a moisture-resistant material having a small shrinkage stress under heating conditions is used.
Specifically, a method in which the film is stretched 2.5 to 4.0 times in the machine direction at a temperature of (Tg + 10) ° C. or more and (Tc + 20) ° C. or less, and then continuously subjected to two-stage transverse stretching at different temperatures. First, (Tc + 20) ° C or more (Tc + 70)
The pre-stage horizontal stretching is performed 1.1 to 2.9 times at a temperature of not more than 0 ° C., and then (Tc + 70) ° C. or more [Tm (melting temperature) −
30] ° C. or lower, and the total transverse stretching ratio is 3.0 to 4.0.
The subsequent horizontal stretching is performed so as to be about 5 times, and then, while being relaxed in the longitudinal direction using a multi-stage roll, and / or 6
A method of suppressing the maximum shrinkage stress of the base layer film by performing a heat treatment with a humidified gas at 0 to 100 ° C.

(3) Adhesion provided between substrate and gas barrier layer
Uses a material with a large compression elastic modulus as a constituent material of the property improvement layer
I do. Specifically, the copolymerized polyester (Tg: -30)
~ 35 ° C, molecular weight: about 5,000-40,000
Degree) into a mixed solvent such as methyl ethyl ketone and toluene.
For example, it is dissolved to about 30%, and the compression modulus
Orthosilicate as metal alcoholate to enhance
About 2 to 30% of ethyl is added to promote hydrolysis and polymerization
A small amount of dilute hydrochloric acid as a catalyst for
Stir in nitrogen and place the resulting solution on the substrate surface for 0.0
5 to 5.0 g / m ^Two Heat at around 60 ° C after coating
Dry and form a gas barrier layer on top
To improve the interlayer adhesion between the base film and gas barrier layer
With shrinkage stress and shrinkage as a whole laminated film
How to control the rate.

(4) A resin composition having a high compression modulus is used for adhesion between the heat seal layer and the gas barrier layer. Specifically, a modified polyester such as an epoxy-modified polyester, an acrylic-modified polyester, or a urethane-modified polyester is dissolved in a mixed solvent such as methyl ethyl ketone, toluene, and cyclohexanone, and the silica sol is added in an amount of about 1 to 25% to increase the compression modulus. After blending, isocyanate is added in an amount of about 5 to 45%, and the mixed solution is used as an adhesive to increase the interlayer adhesion between the gas barrier layer and the heat seal layer, and to suppress the compressive stress and compressibility of the entire laminated film. .

The thickness of the laminated film of the present invention is not particularly limited as long as it satisfies the above-mentioned properties, but it is generally considered in consideration of the practicality, strength, flexibility, economy and the like as a laminated film for packaging. The range is from 10 to 1,000 μm, more usually from 30 to 300 μm. In addition to this laminated film, in addition to a three-layer laminated structure composed of the essential constituent materials described above, or a preferable four-layer laminated structure including an anchor coat layer, in practical use, paper, nonwoven fabric, aluminum foil, and the like may be further used as necessary. Of course, it is also possible to laminate and reinforce, to provide a printing layer or to laminate a printing film.

Since the gas barrier laminate film of the present invention thus obtained hardly loses its gas barrier properties even by the boiling treatment as described above, it can be used as a packaging material for food or the like to be subjected to these treatments in the packaging process. Miso, pickles, side dishes, baby food, boiled tsukudani, konjac, chikuwa,
Kamaboko, processed fishery products, meatballs, hamburgers, genghis khan, ham, sausage, other processed meat products, tea,
Coffee, tea, bonito, toro kelp, potato chips,
Oil confectionery such as butter peanuts, rice confectionery, biscuits, cookies, cakes, buns, castella, cheese, butter, rice cakes, soups, sauces, ramen, wasabi, etc., toothpaste, pet food, pesticides, fertilizers, It can be widely used in various forms, such as bags, lids, cups, tubes, and standing packs, for infusion packs, and also for industrial material packaging such as semiconductor packaging and precision material packaging such as medical, electronic, chemical, and mechanical.

[0051]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples, and the scope of the present invention can be adapted to the above and following points. It is also possible to carry out the present invention with appropriate modifications, and all of them are included in the technical scope of the present invention. In addition, each performance evaluation method adopted in the following examples is as follows.

(Gas Barrier Property) The amount of oxygen permeation was measured using an oxygen permeability measuring device (“OX-TRAN 10 / 50A” Mod).
ern Controls), humidity was 0%, temperature was 25 ° C, and purged for 2 days. In addition, the water vapor transmission rate can be measured by a water vapor transmission rate measuring device (“PERMATRAN” Mode).
rn Controls, Inc.) at a temperature of 40 ° C., a humidity of 90% and a 2-day purge.

(Adhesion strength) According to JIS-K6854,
The s-s curve when the laminate was peeled at 90 degrees was measured by "Tensilon UTM2" manufactured by Toyo Sokki Co., Ltd. An electron microscope and a fluorescent X-ray analyzer manufactured by Rigaku Denki Co., Ltd. were used together to identify the peeling interface between the gas barrier layer and the substrate.

(Shrinkage ratio) The film to be processed is 20 mm in diameter.
Cut into 0 mm circles, vertical, horizontal, and 30 degrees, 45
The degree and the degree are measured at a temperature of 25 ° C. and a humidity of 0%. Then, after boiling at 95 ° C. for 30 minutes, the dimensions in the vertical, horizontal, and 30 °, 45 °, and 60 ° directions are immediately measured, and the shrinkage in each direction is determined.

(Compression Modulus, Shrinkage Stress)
Based on JIS-K7208, “S-ST
The shrinkage stress is determined from the load-deformation curves of the target film in the vertical, horizontal, and 30 °, 45 °, and 60 ° directions.

Example 1 Nylon film (6 nylon, thickness 15 μm, maximum shrinkage stress at 170 ° C .: 900 gf / mm ² , 170 ° C. × 10) as a polyamide resin film serving as a base film
Using the maximum shrinkage after heat treatment of 3.5 minutes: 3.5%, an inorganic vapor-deposited layer was formed in the following procedure.

That is, the above nylon film was vacuum-deposited.
1 × 10 inside the chamber ^-FiveTorr pressure
Holding, SiO_Two : 62% by weight and Al_Two O_Three : 38 weight
% Mixed oxide was evaporated by 15 kW electron beam heating.
270mm thick colorless and transparent inorganic oxide layer with nylon
Deposit on the substrate. Next, a heat seal is placed on the deposition layer.
Unstretched polyethylene (thickness: 55 micron)
) With an adhesive ("A310 / A10" manufactured by Takeda Pharmaceutical Co., Ltd.)
Application amount 2g / m^Two Dry lamination using
Aging at 4 ° C for 4 days to form a gas barrier laminated film
Obtained. Before and after boiling treatment of the laminated film at 95 ° C for 30 minutes
Dimensional change, oxygen permeation after treatment, water vapor permeation
Was measured.

Example 2 In Example 1, as the nylon film substrate,
The maximum shrinkage stress at 170 ° C. is 600 gf / mm ² , 17
Except that a nylon film having a maximum shrinkage of 3.5% after heat treatment at 0 ° C. × 10 minutes was used, and silicon monoxide (SiO) was used as a constituent material of an inorganic oxide layer constituting a gas barrier layer. A gas-barrier laminated film was produced in the same manner as in Example 1, and 95
The dimensional change before and after the boiling treatment at 30 ° C. for 30 minutes, and the oxygen permeation amount and water vapor permeation amount after the treatment were measured.

Example 3 In Example 1, as the base nylon film,
The maximum shrinkage stress at 170 ° C. is 400 gf / mm ² , 17
A gas barrier laminate film was prepared in exactly the same manner except that a nylon film having a maximum shrinkage of 1.5% after heat treatment at 0 ° C. × 10 minutes was used.
The dimensional change before and after the boiling treatment at 30 ° C. for 30 minutes, and the oxygen permeation amount and water vapor permeation amount after the treatment were measured.

Example 4 In Example 1, as the nylon film substrate,
The maximum shrinkage stress at 170 ° C. is 200 gf / mm ² , 17
A gas barrier laminate film was prepared in exactly the same manner except that a nylon film having a maximum shrinkage rate of 0.7% after heat treatment at 0 ° C. × 10 minutes was used.
The dimensional change before and after the boiling treatment at 30 ° C. for 30 minutes, and the oxygen permeation amount and water vapor permeation amount after the treatment were measured.

Comparative Example 1 In the above-described Example 1, the base nylon film was
The maximum shrinkage stress at 170 ° C. is 1200 gf / mm ² , 1
A gas barrier laminate film was prepared in exactly the same manner except that a nylon film having a maximum shrinkage of 4.2% after heat treatment at 70 ° C. for 10 minutes was used.
The dimensional change before and after the boiling treatment at 5 ° C. for 30 minutes, and the oxygen permeation amount and water vapor permeation amount after the treatment were measured.

Comparative Example 2 In Example 1, as the base nylon film,
The maximum shrinkage stress at 170 ° C. is 1200 gf / mm ² , 1
A gas barrier laminate film was prepared in exactly the same manner except that a nylon film having a maximum shrinkage of 3.5% after heat treatment at 70 ° C. for 10 minutes was used.
The dimensional change before and after the boiling treatment at 5 ° C. for 30 minutes, and the oxygen permeation amount and water vapor permeation amount after the treatment were measured.

Comparative Example 3 In Example 1, as the base nylon film,
The maximum shrinkage stress at 170 ° C. is 500 gf / mm ² , 17
A gas barrier laminate film was prepared in exactly the same manner except that a nylon film having a maximum shrinkage of 4.2% after heat treatment at 0 ° C. × 10 minutes was used.
The dimensional change before and after the boiling treatment at 30 ° C. for 30 minutes, and the oxygen permeation amount and water vapor permeation amount after the treatment were measured.

The results are as shown in Table 1 below. In the examples satisfying all the specified requirements of the present invention, very low oxygen and water vapor transmission rates were maintained even after the boiling treatment. In Comparative Examples that do not satisfy the requirements of the invention, the oxygen permeation amount and the water vapor permeation amount after the boiling treatment are significantly increased, and the gas barrier property is significantly deteriorated.

[0065]

[Table 1]

[0066]

The present invention is constituted as described above and exhibits excellent barrier properties under ordinary handling conditions, and does not impair its excellent gas barrier properties even after boiling treatment. It has excellent properties in terms of flexibility, heat sealability, and economic efficiency, and does not impair gas barrier properties even when used for a long period of time under high temperature and high humidity conditions. Therefore, it can be widely and effectively used for a wide range of packaging materials requiring high gas barrier properties, including packaging materials for foods, pharmaceuticals, and industrial materials.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinji Fujita 2-1-1 Katata, Otsu City, Shiga Prefecture Inside Toyo Spinning Co., Ltd. (72) Inventor Yozo Yamada 2-1-1 Katata, Otsu City, Shiga Prefecture (56) References JP-A 1-267036 (JP, A) JP-A 7-290565 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C08J 5/18

Claims (2)

(57) [Claims] 1. A laminated film or sheet in which a gas barrier layer composed of an inorganic vapor-deposited layer is formed on one side or both sides of a base layer composed of a polyamide-based film, and a heat seal layer is further formed. The polyamide-based film has a shrinkage stress in each direction at 170 ° C. of 950 gf / mm ² or less, and a shrinkage rate in each direction of not more than 4.0% when heat-treated at 170 ° C. for 10 minutes. When the laminated film or sheet is boiled at 95 ° C. for 30 minutes, the shrinkage in each direction is 2.5% or less, and the adhesive strength between the base layer and the gas barrier layer after boiled is 100 g / g. der least 15mm is, polyamide film constituting the base layer, [Tg (glass substantially unoriented polyamide based resin sheet
(Las transition temperature) +10] ° C. or more [Tc (crystallization temperature) +2
0] ° C or lower, stretched 2.5 to 4.0 times in the machine direction
At a temperature between [Tc + 20] ° C and [Tc + 70] ° C.
Step transverse stretching is performed, and then [Tc + 70] ° C or higher [Tm
(Melting temperature) -30] ° C or lower, total transverse stretching ratio
Is stretched in the subsequent stage so that is about 3.0 to 4.5 times,
Gas barrier laminate film or sheet, characterized in der Rukoto those obtained by subjecting a subsequent relaxation heat treatment. 2. The gas barrier laminate film or sheet according to claim 1, wherein an adhesion improving layer is provided between the base layer and the gas barrier layer.