JP2000238129A - Manufacture of laminate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a laminate film excellent in gas barrier properties and adhesiveness even at an initial stage and after boiling treatment and also excellent in transparency and bending fatigue resistance. SOLUTION: All inorg. deposited layer and a heat-sealing layer are successively provided on at least the single surface of a biaxially oriented polyamide film. In this case, the biaxially oriented polyamide film is obtained by a sequential biaxial stretching method of a polyamide film comprising a specific polyamide resin having a layered constitution of A/B or A/B/A. In this method, longitudinal stretching is performed over two front and rear stages within a temp. range from a glass transition temp. (Tg)+10 deg.C or higher to low crystallizing temp. (Tc)+20 deg.C or higher so that the total stretching magnification becomes 3.1-4.0 times and the temp. between both stages is not reduced to Tg or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas barrier property and a moisture-proof property, which are important properties in packaging films for fresh foods, processed foods, pharmaceuticals, medical equipment, electronic parts, etc., as well as transparency and handleability. The present invention relates to a method for producing a laminated film having excellent characteristics.

[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 characteristics required for packaging films and sheets have become increasingly severe.

[0003] Temperature, moisture, oxygen,
Deterioration of the quality of products due to ultraviolet rays and the influence of microorganisms such as bacteria and mold 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. Under such circumstances, the permeability of gas and water is low, and the quality of food as a food is not deteriorated by freezing, boiling, retorting, etc. The demand for packaging films is increasing.

[0004] That is, in the packaging of fish meat, animal meat, shellfish, etc., it is important to suppress the oxidation and deterioration of proteins and fats and oils, and to maintain the taste and freshness. It is desired to block the permeation of air by using a. Moreover, when wrapped in a gas barrier film, the fragrance of the contents is retained and the permeation of moisture is prevented, so that the moisture absorption of dried products is suppressed, and the deterioration and solidification due to evaporation of moisture is suppressed in the case of hydrated products. In addition, it is possible to maintain a fresh flavor during packaging for a long time. For these reasons, paste products such as kamaboko, butter, dairy products such as cheese, miso, tea, coffee, ham and sausage, instant food, castella, biscuits and other confectionery packaging films have the gas barrier properties and moisture barrier properties. Is a very important characteristic. These properties are not limited to food packaging films, but are also extremely important as medical products that need to be handled under aseptic conditions or packaging films for electronic components that require rust prevention.

[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, and those in which vinylidene chloride or an ethylene vinyl alcohol copolymer is coated. Further, as a device using an inorganic thin film, a device in which a deposited film of silicon oxide, aluminum oxide, or the like is laminated is also known.

[0006] As a form actually used, a laminate of a polyamide film is provided by providing a sealant layer by a dry lamination method or a sealant layer by an extrusion lamination method on a printed layer and further provided with an adhesive. After the bag is prepared using the laminate and filled with the contents, the opening is heat-sealed, for example, a seasoning such as miso or soy sauce, a water-containing food such as a soup or a retort food, or a medicine is packaged. Offering to the general consumer.

The following problems have been pointed out in the conventional gas barrier films as described above. Aluminum foil laminated as a gas barrier layer is excellent in economics and gas barrier properties, but is opaque, so the contents cannot be seen when packaged, and it does not transmit microwaves, so it can not be processed with a microwave oven .

On the other hand, those coated with vinylidene chloride or ethylene vinyl alcohol copolymer do not have sufficient gas barrier properties against water vapor, oxygen and the like, and the performance is remarkably deteriorated due to high temperature treatment. In addition, there is a concern that vinylidene chloride may cause air pollution due to generation of chlorine gas at the time of incineration.

Therefore, a resin film having an inorganic vapor-deposited layer such as silicon oxide or aluminum oxide formed as a gas barrier layer has been proposed. As a base film on which silicon oxide, aluminum oxide, and the like are deposited, a polyester film (PET) having good dimensional stability has been used.
As a configuration, a laminated structure such as PET / deposited layer / adhesive layer / PET / adhesive layer / unstretched polypropylene (CPP) is generally used. However, a film having such a laminated structure has a drop impact. Insufficient strength is a problem.

On the other hand, PET / deposited layer / adhesive layer / stretched nylon (ONY) / adhesive layer / unstretched polypropylene (CP
In the case of the laminated structure as in P), there is a problem that the gas barrier property after the boiling treatment or the retort treatment is deteriorated due to the shrinkage of the nylon.

Therefore, a film laminated with nylon having a reduced shrinkage during high-temperature hot water treatment (Japanese Patent Laid-Open No. 7-27657).
No. 1) has been proposed. However, since the number of films to be laminated increases, the manufacturing process and the process of transport and storage become complicated, resulting in poor economic efficiency, and the thicker film makes handling difficult, which is not practical.

On the other hand, a gas barrier film using a nylon film as a vapor deposition base material has been studied. However, the nylon film has a large dimensional change due to moisture absorption or heating, so that the barrier property is unstable, and particularly after a boiling treatment or a retort treatment. However, there arises a problem that the gas barrier property is deteriorated.

Therefore, as a measure for improving the gas barrier property, a laminated film (JP-B-7-1264) using stretched nylon, whose shrinkage rate has been reduced in advance by heat treatment, is used as a deposition base material.
No. 9) has been proposed. However, the manufacturing process and the transportation and storage processes become complicated, which is not practical. In addition, nylon having a small shrinkage ratio at the time of high-temperature treatment (in Japanese Patent Publication No. Hei 7-12649, the sum of absolute values of dimensional changes in the vertical and horizontal directions when heated at 120 ° C. for 5 minutes is 2% or less). Even so, excellent gas barrier properties cannot be maintained by boiling treatment, which is high-temperature hot water treatment.

In the case where a nylon film is used as a vapor deposition base material, if water enters between the nylon film and the vapor deposition layer, the adhesive strength between the layers will be significantly reduced, and when used as a packaging bag, it will only break the bag. It is thought that it leads to a decrease in gas barrier properties. As described above, it is pointed out that a gas barrier film having a laminated structure provided with an inorganic vapor-deposited layer such as silicon oxide or aluminum oxide does not always have sufficient strength, and that the gas barrier property deteriorates due to boiling treatment or retort treatment.

[0015] In addition, Japanese Patent Publication No. 51-48511 discloses a gas barrier film which is transparent, allows the contents to be seen through, and is applicable to a microwave oven. A gas barrier film on which SiO ₂ is deposited has been proposed. However, a SiOx-based material having a good gas barrier property (x = 1.3 to 1.8)
The deposited film has a slightly brown color and cannot be said to be sufficient in quality as a transparent gas barrier film. Japanese Patent Application Laid-Open No. 62-101428 describes a device provided with an inorganic vapor-deposited layer mainly composed of aluminum oxide, which not only has insufficient gas barrier properties but also has a problem of bending resistance. is there.

Further, as a gas barrier layer having boiling resistance and retort resistance, although some of which have been proposed in JP-A-2-194944 as an example of Al ₂ O ₃ · SiO ₂ system, Al ₂ O ₃ And a layer of SiO ₂ , and the formation of the gas barrier layer is complicated and requires a large-scale apparatus. In addition, films using these inorganic thin films as gas barrier layers are still inadequate from the viewpoint of achieving both gas barrier properties and flex resistance. That is, in order to provide excellent boiling resistance and retort resistance, a film thickness of at least a certain level (for example, about 2,000 ° or more) is required. It has the problem of not being able to withstand drop impact, has sufficient gas barrier properties and moisture resistance, and has good boiling resistance and retort resistance, and has excellent bending resistance and can withstand drop impact sufficiently. Gas barrier films have not been proposed at present.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide excellent gas barrier properties and adhesion even at the initial stage and after the boil treatment, as well as transparency and bending fatigue resistance. An object of the present invention is to provide a method for producing a laminated film having excellent properties.

[0018]

Means for Solving the Problems In view of the above problems, the present inventors have assiduously studied and finally arrived at the present invention. That is, the object of the present invention is solved by the following means.

1. In a method for producing a laminated film in which an inorganic vapor-deposited layer is laminated on at least one surface of a biaxially oriented polyamide film, and then a heat seal layer, the biaxially oriented polyamide film has an A / B or A / B / A layer structure. A method of successively biaxially stretching a polyamide film obtained by stretching a non-oriented polyamide sheet in the machine direction in the machine direction and then in the transverse direction by 3.0 to 5.0 times,
The longitudinal stretching is performed at a glass transition temperature (Tg) + 10 ° C. or more and a low temperature crystallization temperature (Tc) + 20 ° C. or less, and is stretched into two stages, a former stage and a latter stage, and is stretched at a total stretching ratio of 3.1 to 4.0 times. And a longitudinal stretching without cooling the space between the former stage and the latter stage to Tg or less.
The polyamide resin composition used for the layer A is X shown below.
And a composition comprising Y or a composition comprising X alone, and the polyamide resin composition used for the B layer is a composition comprising Y alone, a composition comprising Y and X,
And any one of the compositions consisting of X, Y, and Z. (X): Aromatic polyamide resin component composed of terephthalic acid and aliphatic diamine or adipic acid and meta-xylylenediamine (a) and aliphatic polyamide resin or aromatic polyamide resin composed of isophthalic acid and aliphatic diamine (b) A resin composition containing the aromatic polyamide resin component (a) in an amount of at least 10 mol% in a mixture / copolymer of (Y): an aliphatic polyamide resin (Z): a flex fatigue resistance improving agent

2. The polyamide resin composition used for the A layer is such that X is 50 to 100 parts by weight and Y is 50 to 100 parts by weight.
The polyamide resin composition obtained by blending 0 parts by weight and used in the B layer is such that X is 0 to 10 parts by weight and Y is 80 parts by weight.
2. The method for producing a laminated film according to the above 1, wherein the laminated film is obtained by blending 0 to 100 parts by weight and 0 to 10 parts by weight of Z.

3. 3. The method for producing a laminated film according to 1 or 2, wherein an anchor coat layer is laminated between the biaxially oriented polyamide film and the inorganic vapor-deposited layer.

4. The inorganic deposition layer is made of silicon oxide and / or
4. The method for producing a laminated film according to any one of the above 1 to 3, wherein the laminated film is a mixture thin film layer of aluminum oxide.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each layer constituting material 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 present invention, the biaxially oriented polyamide film constituting the base layer may be A / B (two kinds of two layers) or A / B.
It is necessary to have a configuration of B / A (two types and three layers). From the viewpoint of curling, an A / B / A configuration that is a symmetric layer configuration is preferable.

The thickness ratio of each layer of the biaxially oriented polyamide film is preferably 5 to 50% for the layer A, more preferably 10 to 40%, and particularly preferably 12 to 40%.
~ 35%. In the case of A / B / A configuration of two and three layers,
The thickness ratio of the surface layer A described above means the sum of the thickness ratios of both surface layers. If the thickness ratio of the layer A is less than 5%, the dimensional stability becomes insufficient and the oxygen permeability deteriorates, which is not preferable. On the other hand, when the thickness ratio of the A layer exceeds 50%,
It is not preferable because the bending fatigue resistance is deteriorated and the number of pinholes is increased.

The polyamide resin composition used for the layer A preferably contains the following composition composed of X and Y, or a composition composed of X alone, and the polyamide resin composition used for the layer B May contain any one of a composition consisting of Y alone, a composition consisting of Y and X, a composition consisting of Y and Z, or a composition consisting of X, Y and Z. preferable.

X is an aromatic polyamide resin component (a) composed of terephthalic acid and aliphatic diamine or adipic acid and meta-xylylenediamine and an aliphatic polyamide resin or an aromatic polyamide resin composed of isophthalic acid and aliphatic diamine It is a resin composition containing the aromatic polyamide resin component (a) in an amount of 10 mol% or more, which is a mixture / copolymer of (b). Further, Y is an aliphatic polyamide-based resin, and Z is a flex fatigue resistance improving agent.

In the polyamide resin composition used for the layer A, the X is 50 to 100 parts by weight, and the Y is 50 to 100 parts by weight.
0 part by weight is preferable, and the polyamide resin composition used for the layer B contains 0 to 10 parts by weight of X,
Preferably, 80 to 100 parts by weight of Y and 0 to 10 parts by weight of Z are blended.

Examples of the aliphatic polyamide used in the present invention include nylon 4, nylon 6, nylon 7, nylon 11, nylon 12, nylon 66, nylon 612, nylon 46, and copolymers and blends thereof. However, nylon 6 and nylon 66 are preferred. In addition, these polyamides may contain small amounts of known substances having known effects such as various antiblocking agents, antistatic agents, stabilizers, etc. as long as their properties are not impaired.

The flex fatigue resistance improving agent used in the present invention includes elastomers such as block polyester amide, block polyether amide, polyether ester amide elastomer, polyester elastomer, modified ethylene propylene rubber, and modified acrylic. / Acrylate copolymer and the like, and these can be mixed and blended.

A feature of the method for producing a laminated film according to the present invention is that, in the method for producing a biaxially oriented polyamide film to be a base film, a substantially unoriented polyamide having an A / B or A / B / A layer constitution is used. The sheet is stretched in two steps in the machine direction, then in the transverse direction, and then heat-set.

More specifically, in the longitudinal stretching of the substantially unoriented polyamide sheet, the first-stage stretching is performed, and the second-stage stretching is performed without cooling to a temperature of Tg or less. Thereafter, the film is stretched laterally at a magnification of 3 times or more, preferably 3.5 times or more, and further heat-fixed. Known longitudinal stretching methods such as hot roll stretching and infrared radiation stretching may be used for the longitudinal stretching.

Hereinafter, a method for producing a biaxially oriented polyamide film as a base material of the laminated film of the present invention will be described in detail. First, in forming a substantially unoriented polyamide sheet having a layer configuration of A / B or A / B / A, the polymers constituting each layer are melted using a separate extruder, co-extruded, and a die is formed. A method in which a polyamide sheet is obtained by quenching and solidifying by cooling on a rotating drum, a method of laminating polymers constituting each layer by lamination, a method in which these are combined, and the like can be used. This polyamide sheet is in a substantially unoriented state.

This unstretched polyamide sheet is first treated with Tg
At a temperature of + 10 ° C. or more and Tc + 20 ° C. or less, 1.1 to
The first-stage longitudinal stretching is performed at a magnification of 3.0 times. The first-stage longitudinal stretching ratio is preferably 1.5 to 2.5 times. If the first-stage longitudinal stretching ratio is 1.1 or less, no stretching effect is exhibited, and if the first-stage longitudinal stretching ratio exceeds 3.0, oriented crystallization proceeds, and the second-stage stretching described later. It is not preferable because the stretching stress increases in the longitudinal stretching by eye and the film is broken or the film is broken in the transverse stretching.

If the first-stage longitudinal stretching temperature is lower than Tg + 10 ° C., necking occurs and thickness unevenness tends to increase.
When the temperature exceeds c + 20 ° C., thermal crystallization remarkably progresses, and the film is easily broken at the time of transverse stretching, which is not preferable. The first-stage longitudinal stretching temperature is preferably in the range of Tg + 20 ° C. to Tc + 10 ° C.

After the first-stage longitudinal stretching, the second-stage longitudinal stretching is performed. One of the features of the present invention is how to adjust the sheet temperature during the second-stage longitudinal stretching. That is, the sheet between the first-stage longitudinal stretching and the second-stage longitudinal stretching is heated and maintained without forcibly cooling, and is also used for preheating or stretching in the second-stage longitudinal stretching. Is also used for heating. If the sheet is forcibly cooled and then reheated for the second-stage longitudinal stretching, thermal crystallization remarkably proceeds, the transverse stretching stress increases, and breakage occurs frequently, which is not preferable. Even in this section of heat insulation that does not cool below Tg,
Although thermal crystallization proceeds, it is much slower than the above-described forced cooling and reheating, and does not pose a practical problem.

Next, this sheet is subjected to a total longitudinal stretching ratio of:
The second-stage longitudinal stretching is performed so that the ratio becomes 3.1 to 4.0 times. If the total longitudinal stretching ratio is less than 3.1 times, the transverse stretching stress is reduced and fracture is reduced, but the strength in the longitudinal direction is reduced, which is not preferable. On the other hand, the total longitudinal stretching ratio is 4.
When it exceeds 0 times, the transverse stretching stress increases remarkably and breakage frequently occurs, which is not preferable. The total longitudinal stretching ratio is from 3.3 to
It is preferably 3.7 times.

The second-stage longitudinal stretching temperature is from Tg + 10 ° C.
Tc + 20 ° C. If the temperature is lower than Tg + 10 ° C., the transverse stretching stress increases remarkably, and rupture frequently occurs.
If the temperature exceeds 0 ° C., the thickness unevenness increases, thermal crystallization remarkably progresses, the transverse stretching stress increases, and breakage occurs frequently, which is not preferable. More preferably, Tg + 20 ° C. to Tc + 10 ° C.
It is.

The uniaxially oriented polyamide film thus obtained is laterally stretched three times or more at a temperature of 100 ° C. to less than the melting point using a stenter, and then heat-fixed and wound. Preferably, the transverse stretching temperature is 100 to 180 ° C, and the transverse stretching ratio is 3.5 times or more. If the stretching temperature is too low, the transverse stretchability deteriorates (breakage occurs), and if it is too high, the thickness unevenness worsens. If the stretching ratio in the transverse stretching is not 3 times or more, the strength in the transverse direction is reduced.

Thus, the longitudinal stretching is divided into two stages,
After performing the longitudinal stretching of the step, without cooling to Tg or less,
Subsequently, by performing the second-stage longitudinal stretching, and then performing the transverse stretching and heat setting, a biaxially oriented polyamide film serving as a base layer of a laminated film having excellent gas barrier properties and moisture resistance can be economically obtained.

The following are conceivable reasons for obtaining the above effects. 1) By performing the longitudinal stretching in two stages, the sheet surface receives a heat history and the thermal crystallization is appropriately promoted, and the surface crystallization of the obtained biaxially oriented polyamide film is promoted. By promoting the surface crystallization, the hygroscopic property of the biaxially oriented polyamide film is reduced, so that the change in the moisture absorption and the change in the size of the boil are reduced. By laminating the inorganic vapor-deposited layer on the biaxially oriented polyamide film, the dimensional change of the inorganic vapor-deposited layer can be suppressed, and it is considered that the inorganic vapor-deposited layer retains the gas barrier property and the moisture-proof property.

2) Not only the effect of reducing the stretching stress by dividing the longitudinal stretching into two stages, but also by heating and maintaining the temperature between the first stretching and the second stretching, a polyamide-specific characteristic generated at the time of forced cooling to reheating. Preventing the crystallization promoting action by hydrogen bonding, furthermore, drawing out the sheet orientation relaxing action after the first-stage stretching and making the structure of the uniaxially oriented film before the transverse stretching gentle, the formation of the transverse orientation which appears during the transverse stretching can be achieved. It is considered that the stretching property was improved and the stretching property was improved by reducing the transverse stretching stress. As a result, there are few operation troubles,
It has become possible to economically produce a biaxially oriented polyamide film for the base layer of a laminated film.

Next, examples of the inorganic vapor-deposited layer constituting the gas barrier layer include silicon oxide, aluminum oxide oxide, magnesium oxide, and mixtures thereof. The term “silicon oxide” used herein includes a mixture of various silicon oxides such as SiO and SiO ₂ , and the term “aluminum oxide” includes a mixture of various aluminum oxides such as AlO and Al ₂ O ₃ . The amount of oxygen bonded differs depending on the production conditions.

In particular, a mixture of aluminum oxide and silicon oxide is preferable as the gas barrier layer in the present invention because of its excellent transparency and bending resistance. Further, a mixture of silicon oxide and aluminum oxide in which the content of aluminum oxide in the gas barrier layer is 5 to 45% by weight is particularly preferable.

If the amount of aluminum oxide in the silicon oxide / aluminum oxide-based vapor-deposited film is less than 5% by weight, there arises a problem that lattice defects occur in the vapor-deposited film and a sufficient gas barrier property cannot be obtained. When the amount of aluminum oxide in the aluminum oxide-based vapor-deposited film exceeds 45% by weight, the flexibility of the film is reduced, and the film is easily broken (cracked or peeled) due to a dimensional change during hot water treatment, and the barrier property is reduced. This causes a problem such as lowering, which does not meet the purpose of the present invention.

The proportion of aluminum oxide is preferably from 10 to 35% by weight, particularly preferably from 15 to 25% by weight. The gas barrier layer may further contain trace amounts (up to 3% by weight) of other oxides and the like as long as the properties are not impaired.

The thickness of the gas barrier layer made of silicon oxide and aluminum oxide is usually 10 to 5,000 °, preferably 50 to 2,000 °. If the film thickness is less than 10 °, it is difficult to obtain a satisfactory gas barrier property.
If the thickness is excessively larger than 000 °, the effect of improving the gas barrier property corresponding thereto cannot be obtained, which is rather disadvantageous in terms of bending resistance and manufacturing cost.

For the production of a silicon oxide / aluminum oxide based deposited film, 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. For example, when a vacuum deposition method is adopted, a mixture of SiO ₂ and Al ₂ O ₃ or a mixture of SiO ₂ and Al is used as a deposition material. Heating may be resistance heating, induction heating, electron beam heating, or the like, and may include oxygen, nitrogen,
It is also possible to introduce reactive gas such as introduction of hydrogen, argon, carbon dioxide, water vapor, or the like, or to use reactive vapor deposition using means such as ozone addition or ion assist. Further, the film forming conditions such as applying a bias to the substrate, heating and cooling the substrate, and the like can be arbitrarily changed. The above-mentioned deposition material, reaction gas, substrate bias, heating / cooling, and the like can be similarly changed when a sputtering method or a CVD method is adopted.

Before or during the vapor deposition, the surface of the biaxially oriented polyamide film serving as the base layer is corona-treated.
It is also effective to perform a flame treatment, a low-temperature plasma treatment, a glow discharge treatment, a reverse sputtering treatment, a surface roughening treatment, etc. to improve the adhesion strength of the deposited film. By forming a silicon oxide / aluminum oxide based thin film having such a composition, it is transparent,
It is possible to obtain a gas barrier film having excellent performance that can withstand the boiling treatment and the gelbo test (bending resistance test).

The gas barrier properties of the laminated film provided with an inorganic vapor-deposited layer on at least one surface of the biaxially oriented polyamide film of the base layer of the present invention and then provided with a sealant layer include the biaxially oriented polyamide film serving as the base layer and the gas barrier layer. The adhesion strength with the layer is greatly related, and the gas adhesion is improved as the adhesion strength increases. According to the examination results of the present inventors, in order to have excellent gas barrier properties and maintain the excellent gas barrier properties even after the boiling treatment, the adhesion strength after the boiling treatment is set to 100 g / 15 m.
m. A more preferable adhesion strength is 150 g / 15 mm or more, further preferably 200 g / 15 mm or more, and further preferably 250 g / 15 mm or more.
It is 15 mm or more. When the adhesion strength is less than 100 g / 15 mm, the gas barrier property tends to be deteriorated by the boiling treatment. It is considered that the reason for this is that if the adhesion strength is high, the inorganic vapor deposition layer is less likely to be peeled off even when the vapor deposition base material slightly shrinks due to boiling treatment or retort treatment.

Means for obtaining such excellent adhesion strength include corona treatment, plasma treatment, glow discharge treatment, reverse sputtering treatment, and rough surface treatment on the surface of a biaxially oriented polyamide film serving as a base layer of an inorganic vapor deposition layer. There is a method such as applying a surface treatment or forming an anchor coat layer for improving adhesion on a polyamide resin film,
Of course, it is not limited to these methods.

The anchor coating agent preferably used for improving the adhesion strength includes a reactive polyester resin, an oil-modified alkyd resin, a urethane-modified alkyd resin,
Melamine-modified alkyd resin, epoxy cured acrylic resin, epoxy resin (using amine, carboxyl group-terminated polyester, phenol, isocyanate, etc. as curing agent), isocyanate resin (amine, urea, carboxylic acid, etc. as curing agent) ), Urethane-polyester resin, polyurethane resin, phenol resin, polyester resin, polyamide resin, reactive acrylic resin, vinyl acetate resin, vinyl chloride resin and the like and copolymers thereof. These can also be used as aqueous resins solubilized and dispersed in water. In addition, it is also effective to use an inorganic coating agent such as a silane coupling agent as the anchor coating agent.

The method for forming the anchor coat layer is as follows.
Either an in-line method of applying at the time of producing the polyamide-based resin film or an off-line method of applying at a separate step from the production of the polyamide-based resin film can be adopted. For the coating, a known coating method, for example, 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 can be adopted.

According to the study results of the present inventors, it is preferable to use an aqueous polyester resin from the viewpoint of cost and hygiene in order to improve the adhesion strength between the base layer and the inorganic vapor deposition layer by forming the anchor coat layer. . Such a polyester resin is obtained by polycondensing a dicarboxylic acid or a tricarboxylic acid with a glycol. Examples of the components used for the polycondensation include acid components such as terephthalic acid, isophthalic acid, adipic acid, and trimellitic acid, and glycol components such as ethylene glycol, neopentyl glycol, butanediol, and ethylene glycol-modified bisphenol A. However, of course, it is not limited to these. The polyester resin may be obtained by graft copolymerization of an acrylic monomer.

The preferred thickness of the anchor coat layer is 0.1.
01 to 10 μm, more preferably 0.02 to 5 μm. When the thickness is less than 0.02 μm, the effect of improving the adhesion strength tends to be hardly exerted. The effect of improving the adhesion described above is not exhibited, and this is economically disadvantageous.

A heat seal layer made of a polyolefin resin is formed on the surface of the inorganic vapor-deposited layer in order to impart thermal adhesiveness. The heat seal layer also functions as a protective layer for the inorganic vapor-deposited layer. In order to effectively perform its function, it is extremely effective to increase the adhesive force between the inorganic vapor-deposited layer and the heat seal layer. It is extremely effective to provide an adhesive layer on the substrate.

The polyolefin resin constituting the heat seal layer does not necessarily have to be a single layer, but may be a multilayer. The resin constituting each layer when forming a multilayer structure is also
Not only a combination of resins of the same kind but also a laminate of a copolymer, a modified product, a blend, or the like of different polymers. For example, in order to enhance the laminating property and the heat sealing property, a polymer having a glass transition temperature (Tg) or a melting point lower than that of the thermoplastic polyolefin resin as a base is compounded, and in order to impart heat resistance, the Tg or the melting point is decreased. It is also possible to composite high polymers.

Various additives such as plasticizers, heat stabilizers, ultraviolet absorbers, antioxidants, coloring agents, fillers, antistatic agents, and the like may be added to the polyolefin resin constituting the heat seal layer, if necessary. It is also possible to blend antibacterial agents, lubricants, antiblocking agents, other resins, and the like.

Particularly preferred as the resin constituting the adhesive layer is a resin having a glass transition temperature in the range of -10 ° C. to 40 ° C., such as a polyurethane resin, a polyester resin, an epoxy resin, a vinyl chloride resin, and acetic acid. Vinyl resins, polyethylene resins, polypropylene resins, melamine resins, acrylic resins, etc., which can be used alone or, if necessary, in combination of two or more, or by melting and mixing, or Examples of the group include a carboxylic acid group, an acid anhydride, (meth) acrylic acid and (meth) acrylic acid.
An adhesive composition containing a compound having an acrylate ester skeleton; an epoxy compound containing a glycidyl group or a glycidyl ether group; a curing agent or a curing accelerator having a reactive functional group such as an oxazoline group, an isocyanate group, an amino group, or a hydroxyl group. It is also effective to use.

The lamination of the polyolefin resin is formed as a heat seal layer on the inorganic vapor deposition layer by a dry lamination method or a wet lamination method using an adhesive, and further by a melt extrusion lamination method or a co-extrusion lamination method. You.

The thus-obtained laminated film or sheet of the present invention makes use of its excellent gas barrier properties, gas barrier durability by boiling treatment and retort treatment and secondary processing characteristics, and is used as a packaging material for miso, pickles, prepared foods, baby foods, Tsukudani, konjac, chikuwa, kamaboko, fishery products,
Meatballs, hamburgers, genghis khan, ham, sausage, other processed meat products, tea, coffee, tea, bonito, kelp, potato chips, butter peanuts and other oil confections, rice crackers, biscuits, cookies, cakes, buns, castella, It can be effectively used for packaging of cheese, butter, rice cake, soup, sauce, ramen, wasabi, toothpaste, etc., and furthermore, pet food, pesticide, fertilizer, infusion pack, semiconductor or precision material packaging, etc. Medical,
It can also be used effectively for packaging of industrial materials such as electronics, chemicals and machinery. The form of the packaging material is not particularly limited, and can be widely applied to bags, lid materials, cups, tubes, standing packs, and the like.

[0062]

Next, the present invention will be described in detail with reference to examples. The present invention is not limited by the following examples, and it is of course possible to carry out the present invention with appropriate modifications within a range that can be adapted to the gist of the preceding and following descriptions. Is included. Various performance tests adopted in the following examples were performed by the following methods.

(1) Oxygen permeability: Measured at a humidity of 0% and a temperature of 25 ° C. using an oxygen permeability measuring device (“OX-TRAN 10 / 50A” manufactured by Modern Controls).

(2) Water Vapor Permeability: Measured at a humidity of 0% and a temperature of 25 ° C. using a water vapor permeability measuring device (“PERMATRAN” manufactured by Modern Controls).

(3) Adhesive strength: The laminated product was peeled off by 180 ° using “Tensilon UTM2” manufactured by Toyo Sokki Co. while adhering water to the interface, and the SS curve between the gas barrier layer and the base material was measured. Measured and determined.

(4) Bending Fatigue Resistance Test: The bending fatigue resistance test (hereinafter referred to as a gelbo test) was evaluated using a gelbo flex tester manufactured by Rigaku Corporation. The condition is (MI
LB131H) DE 112 inch × 8 inch test piece was made into a cylindrical shape having a diameter of 3 (、) inch, both ends were held, the initial grasping interval was 7 inches, and 3 (1/1) of the stroke
2) Add a 400 degree twist in inches. The reciprocating motion of this operation is repeated at a speed of 40 times / min at 1000 times.
Do it twice. The measurement atmosphere is 20 ° C. and the relative humidity is 65%. The number of pinholes at this time was counted.

(5) Glass transition temperature (Tg) and low-temperature crystallization temperature (Tc): An unoriented polyamide sheet was frozen in liquid nitrogen, thawed under reduced pressure, and heated at a rate of 10 ° C./min using a DSC manufactured by Seiko Denshi. The Tg and Tc of the unoriented polyamide sheet were estimated by evaluating and averaging the Tg and Tc of each laminated polyamide sheet, respectively, from the obtained endothermic heat curves.

(6) Film temperature: The temperature in the longitudinal stretching was measured by using a radiation thermometer IR-004 manufactured by Minolta Co., Ltd.

(7) Film-forming condition: The film was successively biaxially stretched under the same conditions for 2 hours, and the number of breaks was examined.

(Example 1) As layer A, 40 parts by weight of a mixture of nylon 6 and 60 parts by weight of a nylon 6T / nylon 6 copolymer (copolymerization ratio 60/40), and as layer B,
100 parts by weight of nylon 6 is melt-extruded from a T-die so as to have a thickness ratio of A / B / A of 10% / 80% / 10%. Electrostatically adhered, cooled and solidified to a thickness of 194μ
m unoriented polyamide sheet was obtained. Tg of this sheet
Was 45 ° C and Tc was 76 ° C.

This sheet was first longitudinally stretched 1.7 times at a stretching temperature of 75 ° C. and then stretched at a stretching temperature of 80 ° C. while maintaining the temperature at 70 ° C.
The second-stage longitudinal stretching was performed so that the total stretching ratio became 3.4 times at 300C, then the sheet was continuously guided to a stenter, transversely stretched 4 times at 130C, heat-fixed at 210C and 6 times. %, And then cooled, and both edges were cut off to obtain a biaxially oriented polyamide film having a thickness of 15 μm. Table 1 shows the film forming situation characteristics at this time. Further, after longitudinal stretching, a water-dispersible acrylic graft polyester resin was coated so as to have a solid content thickness of about 0.1 μm. This film was excellent in both bending fatigue resistance and adhesiveness.

The biaxially oriented polyamide film was sent to a vacuum deposition apparatus, and the inside of the chamber was maintained at a pressure of 1 × 10 ⁻⁵ Torr, and a mixture of 70% by weight of SiO ₂ and 30% by weight of Al ₂ O _{3 was} prepared. The oxide was evaporated by electron beam heating of 15 kW, and a colorless and transparent inorganic oxide layer having a thickness of 200 ° was deposited on the coating surface to form an inorganic deposited layer. Next, unstretched polyethylene (thickness: 55 μm) as a sealant layer was dry-laminated on the inorganic vapor-deposited layer using an adhesive (“A310 / A10” manufactured by Takeda Pharmaceutical Co., 2 g / m ² ), and heated at 45 ° C. For 4 days to obtain a laminated film.

With respect to this laminated film, the following (1) to
The item (5) was evaluated, and the following (6) was evaluated for the biaxially oriented polyamide film of the base layer. (1) Oxygen permeability of untreated film (cc / m ² · atm · da
y) (2) After immersion in hot water of 95 ° C for 30 minutes, oxygen permeability of the film after leaving for 1 hour (cc / m ² · atm · day) (3) After immersion in hot water of 95 ° C for 30 minutes Water vapor permeability of the film after leaving for 1 hour (g / m ² · day) (4) Adhesion force when water is dropped on the peeling interface of the film after being immersed in hot water of 95 ° C. for 30 minutes and left for 1 hour (G /
(5) Number of pinholes (pieces) after bending fatigue test (6) Number of breaks when sequentially biaxially stretched under the same conditions for 2 hours under film forming conditions

(Example 2) The same procedure as in Example 1 was carried out except that a mixture of 25 parts by weight of nylon 6 and 75 parts by weight of a nylon 6T / nylon 6 copolymer (copolymerization ratio 60/40) was used as the A layer. Similarly, a biaxially oriented polyamide film and a laminated film of a base layer were obtained.

Example 3 A biaxially oriented polyamide film and a laminated film of a base layer were obtained in the same manner as in Example 1 except that the first-stage longitudinal stretching temperature was 83 ° C.

Example 4 A biaxially oriented polyamide film and a laminated film of a base layer were obtained in the same manner as in Example 1 except that the second-stage longitudinal stretching temperature was set at 85 ° C.

Comparative Example 1 A biaxially oriented polyamide film and a laminated film of a base layer were obtained in the same manner as in Example 1 except that longitudinal stretching was performed at a stretching temperature of 60 ° C. at 3.4 times in one step. .

Comparative Example 2 A laminated film was produced in the same manner as in Example 1 except that after the first-stage longitudinal stretching, the film was rapidly cooled to 40 ° C. and reheated for the second-stage longitudinal stretching. However, since a large number of breaks occurred during the production of the biaxially oriented polyamide film, a laminated film could not be obtained.

Comparative Example 3 A biaxially oriented polyamide film and a laminated film of a base layer were obtained in the same manner as in Example 1 except that the first-stage longitudinal stretching temperature was set at 50 ° C.

(Comparative Example 4) The first-stage longitudinal stretching temperature was 110 ° C.
A biaxially oriented polyamide film and a laminated film of a base layer were obtained in the same manner as in Example 1 except that the procedure was repeated.

Comparative Example 5 A biaxially oriented polyamide film of a base layer and a laminated film were obtained in the same manner as in Example 1 except that the second-stage longitudinal stretching was performed at 50 ° C.

Comparative Example 6 The second-stage longitudinal stretching temperature was 110 ° C.
A biaxially oriented polyamide film and a laminated film of a base layer were obtained in the same manner as in Example 1 except that the procedure was repeated.

(Comparative Example 7) A biaxially oriented polyamide film and a laminated film of a base layer were obtained in the same manner as in Example 1 except that the total longitudinal stretching ratio was 4.3 times.

Comparative Example 8 A biaxially oriented polyamide film and a laminated film of a base layer were obtained in the same manner as in Example 1 except that 100 parts by weight of nylon 6 was used as the A layer. In addition, Tg of the obtained unoriented polyamide sheet was obtained.
Was 40 ° C and Tc was 68 ° C.

[0085]

[Table 1] (A) Total longitudinal stretching ratio (-) (B) First stage longitudinal stretching temperature (° C) (C) Second stage longitudinal stretching temperature (° C) (D) Nylon 6T / nylon 6 copolymer in A layer Mixing amount (wt%) (1) Oxygen permeability of untreated film (cc / m ² · atm · da
y) (2) After immersion in hot water of 95 ° C for 30 minutes, oxygen permeability of the film after leaving for 1 hour (cc / m ² · atm · day) (3) After immersion in hot water of 95 ° C for 30 minutes Water vapor permeability of the film after leaving for 1 hour (g / m ² · day) (4) Adhesion force when water is dropped on the peeling interface of the film after being immersed in hot water of 95 ° C. for 30 minutes and left for 1 hour (G / 15
(5) Number of pinholes after bending fatigue test (pieces) (6) Number of breaks (times) when biaxially stretched sequentially under the same conditions for 2 hours

[0086]

According to the production method of the present invention, no breakage occurs
Not only has excellent gas barrier properties, but also retains its excellent gas barrier properties even after boil treatment, and has both bending fatigue resistance, and is effective in economically producing excellent laminated films. It is.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // (C08L 77/00 77:12) (C08L 77/00 67:00) B29K 77:00 B29L 9: 00 (72) Inventor Chikao Morishige 2-1-1 Katata, Otsu City, Shiga Prefecture Inside Toyobo Co., Ltd.Research Laboratory (72) Inventor Kiyoji Iseki 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo Co., Ltd. Within the Research Institute (72) Inventor Seiichiro Yokoyama 2-1-1 Katata, Otsu-shi, Shiga F-term (reference) 4F100 AA01B AA19B AA20B AK04 AK46A AK47A AK48A BA03 BA07 BA10A BA10C BA41 EC182 HEGB EH EJ372 EJ38A EJ382 EJ652 GB15 GB23 GB41 GB66 JD02 JD04 JK04 JL05 JL11 JL12C JN01 YY00A 4F210 AA04 AA29 AA30 AB07 AC03 AD02 AD05 AG03 QA02 QA03 QC06 QD04 QD10 QD16 QG01 QG15 QG18 4J002 BB073 BB153 BG003 CF003 CL01X CL03W CL03X CL05W CL083 CL093 GF00 GG02

Claims (4)

[Claims] 1. A method for producing a laminated film in which an inorganic vapor-deposited layer is laminated on at least one side of a biaxially oriented polyamide film, and then a heat seal layer, wherein the biaxially oriented polyamide film is A / B or A / B / A. A biaxially stretching method for a polyamide film obtained by stretching a substantially unoriented polyamide sheet having a layer structure of in the longitudinal direction, and then stretching it in the transverse direction by 3.0 to 5.0 times. The stretching is performed at a temperature of not less than a glass transition temperature (Tg) + 10 ° C. and a temperature of a low temperature crystallization temperature (Tc) + 20 ° C. or less, and is stretched into two stages of a former stage and a latter stage, and a total stretching ratio of 3.1 to 4.0 times is stretched.
A method for producing a laminated film, wherein longitudinal stretching is performed without cooling the space between the former stage and the latter stage to Tg or less. The polyamide resin composition used for the layer A is obtained by blending a composition consisting of X and Y shown below or a composition consisting of X alone, and the polyamide resin composition used for the layer B is Y
It can be obtained by blending any one of a single composition, a composition composed of Y and X, a composition composed of Y and Z, or a composition composed of X, Y and Z. (X): Aromatic polyamide resin component composed of terephthalic acid and aliphatic diamine or adipic acid and meta-xylylenediamine (a) and aliphatic polyamide resin or aromatic polyamide resin composed of isophthalic acid and aliphatic diamine (b) A resin composition containing the aromatic polyamide resin component (a) in an amount of at least 10 mol% in a mixture / copolymer of (Y): an aliphatic polyamide resin (Z): a flex fatigue resistance improving agent 2. The polyamide resin composition used for the layer A is obtained by mixing 50 to 100 parts by weight of the X and 50 to 0 parts by weight of the Y, and the polyamide resin composition used for the layer B is: X is 0 to 10 parts by weight, and Y is 80 to 1 part by weight.
2. The method for producing a laminated film according to claim 1, wherein the laminated film is obtained by mixing 00 parts by weight and 0 to 10 parts by weight of Z. 3. The method according to claim 1, wherein an anchor coat layer is laminated between the biaxially oriented polyamide film and the inorganic vapor-deposited layer. 4. The method according to claim 1, wherein the inorganic vapor-deposited layer is a thin film layer of a mixture of silicon oxide and / or aluminum oxide.