JP7144737B2 - laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminate having excellent heat seal strength and gas barrier properties and a package using the same, and particularly in the process of forming an overcoat layer and the lamination process, the gas barrier layer has few cracks and excellent barrier properties. It relates to a laminate.

Laminated films obtained by heat-sealing or laminating a sealant film are conventionally used as packaging materials such as packages and lids for many distribution goods represented by foods, pharmaceuticals, and industrial products. The innermost surface (the surface in contact with the contents) of the packaging material is provided with a sealant layer made of polyolefin resin such as polyethylene or polypropylene, or copolymer resin such as ionomer or EMMA, which exhibits high sealing strength. It is known that these resins can achieve high adhesion strength by heat sealing.

However, the unstretched sealant film made of polyolefin resin as described in Patent Document 1 easily adsorbs components made of organic compounds such as oils and fats and perfumes, so it is said that the smell and taste of the contents are likely to change. have shortcomings. Therefore, in many cases, it is not suitable to use a sealant layer made of polyolefin resin as the innermost layer for packaging chemical products, pharmaceuticals, foods, and the like.

On the other hand, sealants made of acrylonitrile-based resins, such as those described in Patent Document 2, are less likely to adsorb organic compounds contained in chemical products, pharmaceuticals, foods, etc., and are therefore suitable for use as the innermost layer of packaging materials. there is However, acrylonitrile-based films have a problem of low heat seal strength in a low temperature range (150° C. or lower). In the bag-making process, when the heat sealing temperature becomes high, the maintenance frequency of the seal bar increases, which is not preferable from the viewpoint of productivity. Further, in order to improve the yield of bag making, the speed of the bag making line is increasing, and it is preferable that the sealing temperature is low in response to this requirement as well. Sealants made from acrylonitrile-based resins cannot satisfy these requirements.

In view of such problems, Patent Document 3 discloses a polyester-based sealant having non-adsorption of organic compounds and low-temperature sealing properties. However, the sealant of Patent Literature 3 has the problem that the sealant not only shrinks due to the heat when heat-sealed, but also melts to form holes. For example, when a package using a sealant is produced, heat shrinkage of the sealant not only causes the shape of the bag to be lost, but also causes holes in the bag, which is not preferable because the bag cannot function as a storage bag. Thus, the sealant of Patent Document 3 has room for improvement in heat resistance.

Therefore, Patent Document 4 discloses a sealant with improved heat resistance. The sealant described in Patent Document 4 satisfies heat sealability and heat resistance by separating a layer having heat sealability from other layers and separately controlling the raw material compositions of these layers. However, since the sealant described in Patent Document 4 does not have the ability to block gases such as oxygen and water vapor (gas barrier properties), there is a problem that the shelf life of the contents is short.

Conventionally, as a measure for improving the gas barrier property of a film, a means of providing an inorganic thin film layer composed of an inorganic thin film by vapor deposition is well known. When the inorganic thin film layer is provided, a so-called roll-to-roll system is employed in which a film serving as a substrate is unwound from a film roll and conveyed via a metal roll. This system is preferably adopted because the substrate film passes through each process such as the vapor deposition process while continuously flowing, resulting in good productivity.

In recent years, in order to further improve functionality, it is often the case that a different layer is further laminated on the sealant provided with the aforementioned inorganic thin film layer. For example, overcoating with a composition comprising an organic substance, an inorganic substance, or a mixture of an organic substance and an inorganic substance is expected to further improve gas barrier properties. For example, Patent Document 5 discloses a gas barrier film in which at least a metal oxide thin film layer and a topcoat (overcoat) layer are sequentially laminated on one side of a plastic film. Further, Patent Document 6 discloses a laminated film including a first layer made of a synthetic resin and a second layer made of the same or different composition as the first layer.

Also when laminating different layers as described above, the roll-to-roll method is preferably adopted. However, in the roll-to-roll method, it is necessary to apply a constant tension so that the film does not sag between the metal rolls, and deformation (elongation) of the film due to this tension often poses a problem. A non-stretched film such as that described in Patent Document 1 is greatly stretched by tension, so even if an inorganic thin film layer is provided, a large defect (crack) is likely to occur, resulting in a decrease in gas barrier properties.

In addition, the overcoat film formation or lamination process as described in Patent Documents 5 and 6 (hereinafter, the overcoat film formation process and the lamination process are secondary processing steps, and the film that has exited the secondary processing step is secondary processing ), the gas barrier film, which is the base material, is often heated to a glass transition temperature (Tg) or higher, causing thermal shrinkage. In this case, not only does the gas barrier film, which is the base material, crack easily, but the overcoat layer that is provided also cracks, and curling occurs when laminated. . Furthermore, as the production speed increases, the temperature tends to be kept above Tg even after the film leaves the secondary processing step (cooling rate is slow), so the base film continues to deform. As mentioned above, cracks occur in the inorganic thin film layer and the overcoat layer, resulting in a decrease in gas barrier properties, and curling occurs in secondary processed products. Furthermore, after thermal expansion occurs in the secondary processing step, the base film shrinks when cooled, so that the secondary processed product tends to suffer from cracks and a decrease in gas barrier properties and curling.

Japanese Patent No. 3817846 JP-A-7-132946 International Publication No. 2014-175313 JP 2017-165059 A JP 2017-213789 A JP 2016-179659 A

An object of the present invention is to solve the problems of the prior art as described above. That is, the problems of the present invention are that the components of the content are less adsorbed, the heat seal strength is high in a low temperature range, the gas barrier property is not lowered even if an overcoat layer is provided, and the laminate does not curl even when laminated. Another object of the present invention is to provide a sealant laminate having excellent gas barrier properties and flatness and having excellent suitability for secondary processing.

The present invention consists of the following configurations.
1. A laminate having at least one heat-sealing layer, at least one heat-resistant layer, and at least one inorganic thin film layer, wherein the laminate satisfies the following requirements (1) to (5).
(1) The seal strength when the heat seal layers are sealed at 140 ° C., 0.2 MPa, 2 seconds is 8 N / 15 mm or more and 30 N / 15 mm or less (2) Temperature 40 ° C., relative humidity 90% RH environment water vapor Permeability is 0.05 [g/(m ² d)] or more and 4 [g/(m ² d)] or less (3) Oxygen permeability is 0 in an environment with a temperature of 23 ° C and a relative humidity of 65% RH. .05 [cc/(m ² · d · atm)] or more and 4 [cc / (m ² · d · atm)] or less (4) Tension per unit cross-sectional area of 1.7 N / by thermomechanical analysis (TMA) The deformation rate in the longitudinal direction is 0% or more and 10% or less when the temperature is increased from 30 ° C. to 140 ° C. at 10 ° C./min while applying mm2. While applying a tension of 1.7 N/mm ² , the temperature was raised from 30 ° C. to 160 ° C. at 10 ° C./min, held at 160 ° C. for 1 minute, and then cooled from 160 ° C. to 30 ° C. at 10 ° C./min. Deformation rate in the longitudinal direction is -2% or more and 0% or less (negative value indicates shrinkage)

2. Both the heat-sealing layer and the heat-resistant layer are formed of a polyester containing ethylene terephthalate as a main component, and neopentyl is used as a diol monomer component other than ethylene glycol as a component constituting each polyester constituting each layer. One or more of glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol, and diethylene glycol, or isophthalic acid as an acid component other than terephthalic acid. The laminate according to .
3. Among all monomer components of each polyester component constituting the heat-sealing layer and the heat-resistant layer, a diol monomer component other than the ethylene glycol is contained, and the content of the diol monomer component satisfies the following (1) to (3). 2. The laminate according to .
(1) 30 mol% or more and 50 mol% or less in the heat seal layer (2) 9 mol% or more and 20 mol% or less in the heat-resistant layer (3) The content difference between the heat seal layer and the heat-resistant layer is 20 mol% or more and 35 4. mol % or less; 1. It further comprises an overcoat layer. ~3. The laminate according to any one of .
5. 1 above. ~ 4. A package characterized by using at least a part of the laminate according to any one of the above.

The laminate of the present invention has little adsorption of the components of the contents, has high heat seal strength in a low temperature range, and has excellent workability in secondary processing such as overcoating and lamination.

1 is a schematic diagram of an apparatus for manufacturing an inorganic thin film layer; FIG. It is a diagram obtained by thermomechanical analysis (TMA) to determine the deformation rate when tension is applied.

The present invention provides a laminate having at least one heat-sealing layer, one heat-resistant layer, and one or more inorganic thin-film layers, and characterized by satisfying the following requirements (1) to (5).
(1) The seal strength when the heat seal layers are sealed at 140 ° C., 0.2 MPa, 2 seconds is 8 N / 15 mm or more and 30 N / 15 mm or less (2) Temperature 40 ° C., relative humidity 90% RH environment water vapor Permeability is 0.05 [g/(m ² d)] or more and 4 [g/(m ² d)] or less (3) Oxygen permeability is 0 in an environment with a temperature of 23 ° C and a relative humidity of 65% RH. .05 [cc/(m ² · d · atm)] or more and 4 [cc / (m ² · d · atm)] or less (4) Tension per unit cross-sectional area of 1.7 N / by thermomechanical analysis (TMA) The deformation rate in the longitudinal direction is 0% or more and 10% or less when the temperature is increased from 30 ° C. to 140 ° C. at 10 ° C./min while applying mm2. While applying a tension of 1.7 N/mm ² , the temperature was raised from 30 ° C. to 160 ° C. at 10 ° C./min, held at 160 ° C. for 1 minute, and then cooled from 160 ° C. to 30 ° C. at 10 ° C./min. Deformation rate in the longitudinal direction is -2% or more and 0% or less (negative value indicates shrinkage)
The laminate of the present invention will be described below.

1. Characteristics of Laminate 1.1. Heat Seal Strength The laminate of the present invention has a heat seal strength of 8 N/15 mm or more and 30 N/15 mm or less when the heat seal layers are heat sealed at a temperature of 140° C., a seal bar pressure of 0.2 MPa, and a sealing time of 2 seconds. is preferred. The layer structure of the laminate of the present invention will be described later.
If the heat-seal strength is less than 8 N/15 mm, the heat-sealed portion is easily peeled off and cannot be used as a packaging bag. The heat seal strength is preferably 9 N/15 mm or more, more preferably 10 N/15 mm or more. It is preferable that the heat seal strength is high, but the upper limit that can be obtained at present is about 30 N/15 mm. It can be said that even 29 N/15 mm is sufficiently preferable for practical use.

1.2. Water vapor permeability The laminate of the present invention must have a water vapor permeability of 0.05 [g/(m ² ·d)] or more and 4 g/m ² or less in an environment of a temperature of 40°C and a relative humidity of 90% RH. . If the water vapor transmission rate exceeds 4 [g/(m ² ·d)], the shelf life of the contents will be shortened when used as a bag containing the contents, which is not preferable. On the other hand, when the water vapor permeability is less than 0.05 [g/(m ² ·d)], the gas barrier property is enhanced and the shelf life of the contents is increased, which is preferable, but the current technical level is 0.05 [g /(m ² ·d)] is the lower limit. Even if the lower limit of the water vapor permeability is 0.05 [g/(m ² ·d)], it can be said that it is practically sufficient. The upper limit of the water vapor permeability is preferably 3.8 [g/(m ² ·d)], more preferably 3.6 [g/(m ² ·d)].

1.3. Oxygen permeability The laminate of the present invention has an oxygen permeability of 0.05 [cc/(m ² · d · atm)] or more and 4 [cc / (m ² ) in an environment of a temperature of 23 ° C. and a relative humidity of 65% RH.・d・atm)]. If the oxygen permeability exceeds 4 [cc/(m ² ·d·atm)], the shelf life of the contents will be shortened, which is not preferable. On the other hand, when the oxygen permeability is less than 0.05 [cc/(m ² ·d · atm)], the gas barrier property is enhanced and the shelf life of the contents is increased, which is preferable, but the current technical level is oxygen permeability is 0.05 [cc/(m ² ·d·atm)]. Even if the lower limit of the oxygen permeability is 0.05 [cc/(m ² ·d·atm)], it can be said to be practically sufficient. The upper limit of the oxygen permeability is preferably 3.8 [cc/(m ² ·d·atm)], more preferably 3.6 [cc/(m ² ·d·atm)].

1.4. Heat deformation rate when tension is applied The laminate of the present invention is 10 ° C./min from 30 ° C. to 140 ° C. while applying a tension of 1.7 N / mm ² per unit cross-sectional area (width x thickness) in the longitudinal direction. It is preferable that the deformation rate when heated is 0% or more and 10% or less. Longitudinal heat distortion is measured using thermomechanical analysis (TMA). A detailed measurement method is described in Examples. The longitudinal direction refers to the film-forming direction in the production of the sealant film, and is synonymous with the longitudinal direction and the MD direction, which will be described later.
If the heat deformation rate in the longitudinal direction exceeds 10%, it means that the laminate that becomes the base material is likely to stretch in the secondary processing step, and when an overcoat layer is provided, the overcoat layer is likely to crack. It is not preferable because it becomes curled and the laminated product curls. The heat deformation rate in the longitudinal direction is more preferably 9% or less, more preferably 8% or less. The closer the heat deformation ratio in the longitudinal direction is to 0%, the more difficult it is for the laminate to deform. It is not preferable because it becomes curled and the laminated product curls. In the present invention, the lower limit of the heat distortion rate in the longitudinal direction is 0%, and even 1% is practically preferable enough.

1.5. Cooling deformation rate when tension is applied The laminate of the present invention is heated from room temperature to 160 ° C. at 10 ° C./min while applying a tension of 1.7 N / mm ² per unit cross-sectional area (width x thickness) in the longitudinal direction. After holding at 160 ° C. for 1 minute, the deformation rate when cooling from 160 ° C. to 30 ° C. at 10 ° C./min is -2% or more and 0% or less (negative value indicates shrinkage) preferable. Longitudinal cooling shrinkage is measured using thermo-mechanical analysis (TMA). A detailed measurement method is described in Examples.
If the cooling shrinkage in the longitudinal direction is less than -2%, it means that the laminate tends to shrink after leaving the secondary processing process, and the overcoat layer tends to crack and the laminate curls. I don't like it because I can't put it away. The cooling shrinkage in the longitudinal direction is more preferably −1.8% or more, more preferably −1.6% or more. The closer the longitudinal cooling shrinkage rate is to 0%, the more difficult it is for the laminate to deform. It is not preferable because it becomes easy to enter and the laminate product curls. In the present invention, the upper limit is 0% because only shrinkage occurs during cooling. Even if the upper limit of the cooling shrinkage rate in the longitudinal direction is -0.2%, it can be said that it is sufficiently preferable for practical use.

1.6. Hot water heat shrinkage The laminate of the present invention preferably has a hot water heat shrinkage of −5% or more and 5% or less in both the width direction and the longitudinal direction when treated in hot water at 98° C. for 10 seconds. . If the shrinkage ratio exceeds 5%, the shrinkage in a high-temperature environment increases and the original shape cannot be maintained. The hot water heat shrinkage rate is more preferably 4% or less, and even more preferably 3% or less. On the other hand, when the hot water heat shrinkage ratio is less than 0%, it means that the laminate is stretched, and it is not preferable because the film cannot maintain its original shape similarly to the case where the shrinkage ratio is high.

1.7. Haze The laminate of the present invention preferably has a haze of 1% or more and 15% or less. If the haze exceeds 15%, the transparency of the laminate is deteriorated, and the visibility of the contents is deteriorated when the laminate is used as a package such as a bag. The upper limit of haze is more preferably 13% or less, particularly preferably 11% or less. The lower the haze, the higher the transparency, which is preferable. However, in the current state of the art, 1% is the lower limit, and 2% or more is practically sufficient.

1.8. Thickness The thickness of the laminate of the present invention is not particularly limited, but is preferably 3 μm or more and 200 μm or less. If the thickness of the laminate is less than 3 μm, the heat seal strength may be insufficient and processing such as printing may become difficult, which is not so preferable. Although the thickness of the laminate may be thicker than 200 μm, it is not preferable because the weight of the laminate used increases and the chemical cost increases. The thickness of the laminate is more preferably 5 μm or more and 160 μm or less, and even more preferably 7 μm or more and 120 μm or less.

1.9. Types of Contents and Adsorption Amount The sealant of the present invention is characterized by being less likely to adsorb organic compounds contained in chemical products, pharmaceuticals, foods, and the like. Examples of the organic compounds include d-limonene, citral, citronellal, p-menthane, pinene, terpinene, myrcene, carene, geraniol, nerol, citronellal, terpineol, l-menthol, nerolidol, borneol, dl-camphor, lycopene. , carotene, trans-2-hexenal, cis-3-hexenol, β-ionone, selinen, 1-octen-3-ol, benzyl alcohol, octal tulobuterol hydrochloride, and tocopherol acetate. .
The amount of adsorption to the sealant varies depending on the adsorption conditions (concentration of adsorbate, storage period, temperature, etc.), but the amount of adsorption when stored for one week by the method shown in the examples below is 0 μg/cm ² or more and 2 μg/cm. ² is preferred. An adsorption amount of 0 μg/cm ² indicates that the contents are not adsorbed to the sealant at all. The adsorption amount is more preferably 1.8 μg/cm ² or less, more preferably 1.6 μg/cm ² or less.
Since the sealant of the present invention has a heat-sealable layer made of a polyester-based component, there is a possibility that the adsorption of organic compounds having a similar chemical structure may increase. Specifically, since the polyester-based component constituting the sealant has four oxygen atoms, as the chemical structure of the organic compound, the greater the number of oxygen atoms (approaching four), the greater the solubility of the organic compound in the sealant. Adsorptivity tends to increase with For example, packaging a content containing eugenol with two oxygen atoms or methyl salicylate with three oxygen atoms is not preferable because the adsorption amount tends to exceed 2 μg/cm ² .

2. Layer Configuration and Layer Ratio of Laminate The laminate of the present invention must have a configuration of three or more layers, each having at least one heat-seal layer, one heat-resistant layer, and one inorganic thin film layer. Constituent requirements for each layer will be described later, but the layer with the highest ethylene terephthalate component content is the heat-resistant layer. The inorganic thin film layer and the heat-resistant layer may be positioned at any position, but the heat-sealing layer should be the outermost layer in order to develop the necessary heat-sealing strength. A preferable order of the layers is a configuration in which the outermost layer is the sealing layer and the inorganic thin film layer, and the heat-resistant layer is in the middle.
Moreover, the layer structure of the laminate may have one or more layers other than the heat seal layer, the heat resistant layer, and the inorganic thin film layer. Specifically, it includes an anchor coat layer provided below the inorganic thin film layer, an overcoat layer provided above the inorganic thin film layer, and a resin layer (film) other than the resin layer constituting the laminate of the present invention. Details will be described later.
The ratio of the heat seal layer to the thickness of the entire laminate is preferably 20% or more and 80% or less. If the layer ratio of the heat-sealing layer is less than 20%, the heat-sealing strength of the laminate is lowered, which is not preferable. If the layer ratio of the heat seal layer exceeds 80%, the heat seal strength of the laminate is improved, but the heat resistance is lowered, which is not preferable. The layer ratio of the heat seal layer is more preferably 30% or more and 70% or less.

The thickness of the inorganic thin film layer is preferably 2 nm or more and 100 nm or less (the ratio of the thickness of the inorganic thin film layer to the thickness of the entire laminate is so small that it can be ignored). If the thickness of the inorganic thin film layer is less than 2 nm, it becomes difficult to satisfy the predetermined oxygen permeability and water vapor permeability, which is not preferable. On the other hand, even if the thickness of the inorganic thin film layer exceeds 100 nm, there is no corresponding effect of improving the gas barrier properties, and the manufacturing cost increases, which is not preferable. The thickness of the inorganic thin film layer is more preferably 5 nm or more and 97 nm or less, and even more preferably 8 nm or more and 94 nm or less.
In addition, the outermost layer (including the heat seal layer) of the laminate of the present invention may be provided with a layer subjected to corona treatment, coating treatment, flame treatment, or the like in order to improve the printability and slipperiness of the film surface. is also possible, and can be arbitrarily provided within a range not deviating from the requirements of the present invention.

3. Constituent Raw Materials of Laminate In the following, a three-layer structure consisting of a heat-seal layer, a heat-resistant layer, and an inorganic thin film layer, which is an essential embodiment of the present invention, will be described. In the following description, the sealing layer and the heat-resistant layer are collectively referred to as a "polyester-based resin layer" to distinguish them from the inorganic thin film layer mainly composed of inorganic substances.

3.1. Polyester resin layer 3.1.1. Type of Polyester Raw Material The type of polyester raw material that constitutes the polyester-based resin layer of the present invention is one that contains an ethylene terephthalate unit as a main component. Here, "contained as a main component" means to contain 50 mol% or more when the total amount of the components is 100 mol%.
Moreover, it is preferable that the polyester used in the polyester-based resin layer of the present invention contains at least one component other than ethylene terephthalate. This is because the presence of components other than ethylene terephthalate improves the heat seal strength of the heat seal layer. In the heat-resistant layer, it is preferable that the amount of components other than ethylene terephthalate is small, but by including components other than ethylene terephthalate, the difference in shrinkage rate from that of the heat seal layer can be reduced, and the curl of the laminate can be reduced. There is Since the content of each component differs between the heat seal layer and the heat resistant layer, it will be described later.
Examples of dicarboxylic acid monomers that can be components other than terephthalic acid constituting ethylene terephthalate include aromatic dicarboxylic acids such as isophthalic acid, 1,4-cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and orthophthalic acid, adipic acid, Aliphatic dicarboxylic acids such as azelaic acid, sebacic acid, decanedicarboxylic acid, and alicyclic dicarboxylic acids are included. However, it is preferable not to include polyvalent carboxylic acids having a valence of 3 or higher (eg, trimellitic acid, pyromellitic acid, anhydrides thereof, etc.) in the polyester. Among the above carboxylic acid components, isophthalic acid is preferably used because the heat seal strength between the heat seal layers can be easily adjusted to 8 N/15 mm or more.

Examples of diol monomers that can be components other than ethylene glycol constituting ethylene terephthalate include neopentyl glycol, 1,4-cyclohexanedimethanol, diethylene glycol, 2,2-diethyl 1,3-propanediol, 2-n- Butyl-2-ethyl-1,3-propanediol, 2,2-isopropyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, hexanediol, 1,4- Examples include long-chain diols such as butanediol, aliphatic diols such as hexanediol, and aromatic diols such as bisphenol A. However, the polyester should not contain a diol having 8 or more carbon atoms (e.g., octanediol, etc.) or a trihydric or higher polyhydric alcohol (e.g., trimethylolpropane, trimethylolethane, glycerin, diglycerin, etc.). preferable.
Furthermore, polyester elastomers containing ε-caprolactone, tetramethylene glycol, etc. may be included as components constituting the polyester. A polyester elastomer has the effect of lowering the melting point of the polyester-based resin layer, so it can be suitably used particularly for the heat seal layer.

Among these, by using one or more of neopentyl glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol, and diethylene glycol, the heat seal strength between the heat seal layers can easily be 8 N / 15 mm or more. It is preferable because It is more preferable to use one or more of neopentyl glycol and 1,4-cyclohexanedimethanol, and it is particularly preferable to use neopentyl glycol.

In the polyester-based resin layer of the present invention, various additives such as waxes, antioxidants, antistatic agents, crystal nucleating agents, viscosity reducing agents, heat stabilizers, coloring pigments, An anti-coloring agent, an ultraviolet absorber, etc. can be added. Further, it is preferable to add fine particles as a lubricant for improving the slipperiness of the laminate to at least one of the outermost layers of the laminate. Any fine particles can be selected. For example, inorganic fine particles include silica, alumina, titanium dioxide, calcium carbonate, kaolin, barium sulfate, etc., and organic fine particles include acrylic resin particles, melamine resin particles, silicone resin particles, crosslinked polystyrene. Particles and the like can be mentioned. The average particle size of the fine particles can be appropriately selected within the range of 0.05 to 3.0 μm as measured by a Coulter counter.
As a method of blending particles in the polyester resin layer of the present invention, for example, it can be added at any stage of producing a polyester resin (resin), but the esterification stage or after the completion of the transesterification reaction. It is preferable to add a slurry dispersed in ethylene glycol or the like before starting the polycondensation reaction to proceed with the polycondensation reaction. In addition, a method of blending a polyester resin raw material with a slurry of particles dispersed in ethylene glycol, water, or other solvents using a kneading extruder with a vent, or a method of kneading and extruding dried particles and a polyester resin raw material. A method of blending using a machine is also included.

3.1.2. Component amount of polyester raw material contained in the heat seal layer The polyester used for the heat seal layer has a content of dicarboxylic acid monomer and / or diol monomer that is a component other than terephthalic acid and ethylene glycol constituting ethylene terephthalate is 30 mol% or more. is preferably 32 mol % or more, and particularly preferably 34 mol % or more. Further, the upper limit of the content of monomers other than ethylene terephthalate is 50 mol %.
If the amount of the monomer other than ethylene terephthalate contained in the heat seal layer is less than 30 mol %, even if the molten resin is rapidly solidified after being extruded from the die, it will crystallize during the subsequent stretching and heat setting steps. Therefore, it is difficult to obtain a heat seal strength of 8 N/15 mm or more, which is not preferable.
On the other hand, when the amount of the monomer other than the ethylene terephthalate contained in the heat seal layer is 50 mol% or more, the heat seal strength of the laminate can be increased, but the heat resistance of the heat seal layer is extremely low. As a result, when heat-sealing, the periphery of the seal is blocked (a phenomenon in which the seal is made in a wider area than intended due to heat conduction from the heating member), making proper heat-sealing difficult. Become. The content of monomers other than ethylene terephthalate is more preferably 48 mol % or less, particularly preferably 46 mol % or less.

3.1.3. Component amount of polyester raw material contained in the heat-resistant layer The polyester used for the heat-resistant layer has a content of dicarboxylic acid monomers and/or diol monomers that are components other than terephthalic acid and ethylene glycol that constitute ethylene terephthalate is 9 mol% or more. is preferred, 10 mol % or more is more preferred, and 11 mol % or more is particularly preferred. Further, the upper limit of the content of monomers other than ethylene terephthalate is 20 mol %.
If the amount of the monomer other than the ethylene terephthalate contained in the heat-resistant layer is less than 9 mol %, the difference in thermal shrinkage with the sealing layer increases, and the curling of the laminate increases, which is not preferable. If the difference in the content of the monomers other than the ethylene terephthalate contained in the heat-resistant layer and the seal layer increases, the difference in thermal shrinkage between the layers during heat setting increases, even if the cooling after heat setting is strengthened. However, the shrinkage toward the sealing layer side becomes large, and the curl becomes large.
On the other hand, when the amount of the monomer other than the ethylene terephthalate contained in the heat-resistant layer is 20 mol% or more, the heat resistance of the laminate is lowered such that the heat applied during heat sealing causes holes. I don't like it because I can't put it away. The content of monomers other than ethylene terephthalate is more preferably 19 mol % or less, particularly preferably 18 mol % or less.
Further, the content of monomers other than ethylene terephthalate for controlling curling should be such that the difference between the seal layer and the heat-resistant layer is 10 mol % or more and 45 mol % or less, in addition to the amount of each layer alone. It is more preferable if there is, and more preferably 11 mol % or more and 44 mol % or less.

3.2. Raw material species and composition of inorganic thin film layer The raw material species of the inorganic thin film layer constituting the laminate of the present invention is not particularly limited, and conventionally known materials can be used. can be selected as appropriate. Examples of raw material species for the inorganic thin film layer include metals such as silicon, aluminum, tin, zinc, iron, and manganese, and inorganic substances or inorganic compounds containing one or more of these metals. oxides, nitrides, carbides, and fluorides of These inorganic substances or inorganic compounds may be used singly or in combination. In particular, it is preferable to use silicon oxide or aluminum oxide singly (one element) or in combination (binary element) because the transparency of the laminate can be improved. When the component of the inorganic compound consists of a binary of silicon oxide and aluminum oxide, the content of aluminum oxide is preferably 20% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 70% by mass or less. . If the content of aluminum oxide is 20% by mass or less, the density of the inorganic thin film layer may decrease and the gas barrier properties may deteriorate, which is not preferable. On the other hand, if the content of aluminum oxide is 80% by mass or more, the flexibility of the inorganic thin film layer is lowered, cracks are likely to occur, and as a result, gas barrier properties may be lowered.
If the oxygen/metal element ratio of the metal oxide used for the inorganic thin film layer is 1.3 or more and less than 1.8, it is preferable because the gas barrier properties are less varied and excellent gas barrier properties can always be obtained. The oxygen/metal element ratio can be obtained by measuring the amount of each element of oxygen and metal by X-ray photoelectron spectroscopy (XPS) and calculating the oxygen/metal element ratio.

4. Production Conditions of Laminate The laminate of the present invention is preferably produced by a method of producing a polyester-based resin layer and then forming an inorganic thin film layer thereon. The laminate may be provided with an inorganic thin film layer continuously after the polyester resin layer is produced (online film formation), once the resin layer is wound up to form a film roll, and then the film roll is unwound. An inorganic thin film layer may be provided (offline film formation). Below, the manufacturing method of the laminated body assuming offline film-forming is described.

4.1. Film forming conditions for polyester resin layer 4.1.1. Melt Extrusion The polyester-based resin layer of the present invention is prepared according to the above 3.1.1. It can be obtained by melt-extruding the polyester raw material described in "Raw Material Species of Polyester-Based Resin Layer" with an extruder to form an unstretched film, and stretching it by a predetermined method shown below. When the polyester-based resin layer includes a heat-sealing layer, a heat-resistant layer, or other layers, the layers may be laminated before or after stretching. When the layers are laminated before being stretched, it is preferable to adopt a method in which the raw material resins for each layer are melt-extruded by separate extruders and joined using a feed block or the like in the middle of the resin flow path. In the case of lamination after stretching, lamination, in which separately formed resin layers (films) are adhered with an adhesive, or extrusion lamination, in which melted polyester resin is poured onto the surface layer of individual or laminated films, is adopted. is preferred. Among these, the method of laminating each layer before stretching is preferable.
As described above, the polyester-based resin can be obtained by polycondensation by selecting the types and amounts of the dicarboxylic acid component and the diol component so as to contain an appropriate amount of a monomer that can be a component other than ethylene terephthalate. Moreover, two or more kinds of chip-like polyesters can be mixed and used as a raw material for the polyester-based resin layer.

When the raw material resin is melt-extruded, it is preferable to dry the polyester-based raw material for each layer using a dryer such as a hopper dryer, a paddle dryer, or a vacuum dryer. After drying the polyester-based raw material for each layer, it is melted at a temperature of 200 to 300° C. using an extruder and extruded as a laminated film. Any existing method such as a T-die method, a tubular method, or the like can be employed for the extrusion.
Thereafter, by rapidly cooling the film melted by extrusion, an unstretched film can be obtained. As a method for rapidly cooling the molten resin, a method of obtaining a substantially non-oriented resin sheet by casting the molten resin from a die onto a rotating drum and rapidly cooling and solidifying the resin can be suitably employed.
The polyester-based resin layer may be formed by any of non-stretching, uniaxial stretching (stretching in at least one of the vertical (longitudinal) direction and horizontal (width) direction), and biaxial stretching. From the viewpoint of mechanical strength and productivity of the laminate of the present invention, uniaxial stretching is preferable, and biaxial stretching is more preferable. In the following, the description will focus on the sequential biaxial stretching method by longitudinal stretching and then transverse stretching, in which the longitudinal stretching is performed first, and then the transverse stretching. It does not matter because only the main orientation direction is changed. A simultaneous biaxial stretching method in which the film is stretched in the machine direction and the transverse direction at the same time may also be used.

4.1.2. First (Longitudinal) Stretching For stretching in the first direction (longitudinal or longitudinal direction), the unstretched film is preferably introduced into a longitudinal stretching machine in which a plurality of roll groups are continuously arranged. In longitudinal stretching, it is preferable to preheat the film with preheating rolls until the film temperature reaches 65°C to 90°C. If the film temperature is lower than 65° C., it becomes difficult to stretch the film in the longitudinal direction, and the film tends to break, which is not preferable. On the other hand, if the temperature is higher than 90° C., the film tends to stick to the roll, and the film tends to wind around the roll or stain the roll during continuous production, which is not preferable.
When the film temperature reaches 65°C to 90°C, it is longitudinally stretched. The longitudinal draw ratio is preferably 1-fold or more and 5-fold or less. Since 1 time means no longitudinal stretching, the longitudinal stretching ratio is 1 time to obtain a transversely uniaxially stretched film, and the longitudinal stretching ratio is 1.1 times or more to obtain a biaxially stretched film. By setting the longitudinal draw ratio to 1.1 times or more, the mechanical strength can be increased by imparting molecular orientation to the longitudinal direction of the film, so that the heat deformation ratio during application of tension can be easily reduced to 10% or less. The upper limit of the draw ratio in the longitudinal direction may be any number, but if the draw ratio in the longitudinal direction is too high, it becomes difficult to draw in the transverse direction and the film tends to break, so it is preferably 5 times or less.

4.1.3. Intermediate Heat Treatment After the first (longitudinal) stretching, it is preferable to include a step of heating the film (intermediate heat treatment) in order to reduce the shrinkage of the film caused by the stretching. At the time of this intermediate heat treatment, fixed-length heating in which the film is heated while maintaining the length of the film constant, or relaxation treatment in which the film is heated while being relaxed in the longitudinal direction, or the like can be employed. Among these, in order to reduce the shrinkage rate in the longitudinal direction of the film caused by longitudinal stretching, it is a preferred embodiment to employ relaxation treatment.

Relaxation in the longitudinal direction can reduce not only the shrinkage rate in the longitudinal direction of the film, but also the bowing phenomenon (distortion) occurring in the tenter. This is because in the second (horizontal) stretching and final heat treatment in the post-process, the film is heated while both ends in the width direction are held, so that only the central portion of the film shrinks in the longitudinal direction. The relaxation rate in the longitudinal direction is preferably 0% or more and 70% or less (0% relaxation rate means no relaxation). Since the upper limit of the rate of relaxation in the longitudinal direction is determined by the raw materials used and conditions for longitudinal stretching, the relaxation cannot be performed beyond this limit. In the polyester sealant of the present invention, the upper limit of the relaxation rate in the longitudinal direction is 70%. To relax in the longitudinal direction, heat the film after longitudinal stretching at a temperature of 65 ° C. to 100 ° C. or less, adjust the speed difference of the rolls (lower the roll speed on the downstream side), or shorten the distance between clips ( can be implemented by slowing down the moving speed on the downstream side). Any of rolls, near-infrared rays, far-infrared rays, hot air heaters, etc. can be used as the heating means. In addition, relaxation in the longitudinal direction can be performed by narrowing the clip spacing in the longitudinal direction not only immediately after longitudinal stretching, but also in transverse stretching (including a preheating zone) or final heat treatment (in this case, both ends of the film in the width direction are relaxed in the longitudinal direction, bowing distortion is reduced), and can be performed at any time.
After relaxing in the longitudinal direction (longitudinal stretching if relaxation is not performed), the film is preferably cooled once, preferably with cooling rolls having a surface temperature of 20 to 40°C.

4.1.4. Second (horizontal) stretching After the first (longitudinal) stretching, the film is stretched at 65°C to 110°C for 3 to 5 minutes while both ends of the film in the width direction (perpendicular to the longitudinal direction) are held with clips in the tenter. It is preferable to perform lateral stretching at a draw ratio of about 100%. Preheating is preferably performed before stretching in the transverse direction, and the preheating is preferably performed until the film surface temperature reaches 75°C to 120°C.
After transverse stretching, the film is preferably passed through an intermediate zone in which no active heating operation is performed. Since the temperature in the final heat treatment zone is higher than that in the transverse stretching zone of the tenter, the heat (hot air itself or radiant heat) in the final heat treatment zone flows into the transverse stretching process unless an intermediate zone is provided. In this case, since the temperature of the lateral stretching zone is not stable, not only is the accuracy of the thickness of the film deteriorated, but also the physical properties such as the heat seal strength and the heat shrinkage are varied. Therefore, it is preferable that the transversely stretched film is passed through an intermediate zone for a predetermined period of time, and then subjected to final heat treatment. In this intermediate zone, when a strip of paper is hung without the film passing through it, the accompanying flow accompanying the running of the film, the transverse stretching zone and the final It is important to block hot air from the heat treatment zone. About 1 to 5 seconds is sufficient for passing through the intermediate zone. If it is shorter than 1 second, the length of the intermediate zone will be insufficient and the heat shielding effect will be insufficient. On the other hand, it is preferable that the intermediate zone is long.

4.1.5. Final Heat Treatment After passing through the intermediate zone, heat treatment is preferably performed at 160° C. or higher and 250° C. or lower in the final heat treatment zone. If the final heat treatment temperature is less than 160°C, the laminate will not only have a heat deformation rate of less than 0% (shrink) when tension is applied, but will also have a 98°C hot water shrinkage rate of more than 5%. I don't like it because I can't put it away. The higher the final heat treatment temperature, the more difficult it is for the heat deformation rate of the film to fall below 0% when tension is applied, and the 98°C hot water shrinkage rate decreases. , the film may melt and drop into the tenter during the final heat treatment step, which is not preferable.
At the time of the final heat treatment, shrinkage in the width direction can be reduced by reducing the distance between the clips of the tenter by an arbitrary ratio (relaxation in the width direction). Therefore, in the final heat treatment, it is preferable to perform relaxation in the width direction within a range of 0% or more and 10% or less (a relaxation rate of 0% indicates that no relaxation is performed). The higher the relaxation ratio in the width direction, the lower the shrinkage ratio in the width direction. , so relaxation cannot be performed beyond this. In the sealant of the present invention, the upper limit of the relaxation rate in the width direction is 10%. Moreover, during the final heat treatment, as described above, the distance between the clips of the tenter can be shortened by an arbitrary ratio in the longitudinal direction (relaxation in the longitudinal direction).
The passing time through the final heat treatment zone is preferably 2 seconds or more and 20 seconds or less. If the passing time is less than 2 seconds, the film passes through the heat treatment zone before the surface temperature of the film reaches the set temperature, so the heat treatment is meaningless. The longer the passing time, the better the effect of heat treatment. Therefore, it is preferably 2 seconds or longer, more preferably 5 seconds or longer. However, if the transit time is increased, the equipment will become huge, so 20 seconds or less is practically sufficient.

4.1.6. Cooling After passing through the final heat treatment zone, it is preferable to cool the film with cooling air at 10°C or higher and 30°C or lower in the cooling zone. At this time, the cooling efficiency is improved by decreasing the temperature of the cooling air or increasing the air velocity so that the actual temperature of the film at the exit of the tenter becomes lower than the glass transition temperature of the sealing layer or the heat-resistant layer, whichever is lower. is preferred. The actual temperature is the film surface temperature measured with a non-contact radiation thermometer. If the actual temperature of the film at the exit of the tenter exceeds the glass transition temperature, the film will thermally shrink when both ends of the film held by the clips are released. At this time, the film curls into a seal layer having a large heat shrinkage, which is not preferable.
The passing time through the cooling zone is preferably 2 seconds or more and 20 seconds or less. If the passing time is 2 seconds or less, the film passes through the cooling zone before the surface temperature reaches the glass transition temperature, resulting in large curls. The longer the passing time, the higher the cooling effect. Therefore, it is preferably 2 seconds or longer, more preferably 5 seconds or longer. However, if the transit time is increased, the equipment will become huge, so 20 seconds or less is practically sufficient.
Then, by winding the film while cutting and removing both ends of the film, a film roll of a polyester-based resin layer is obtained.

4.2. Film formation conditions of inorganic thin film layer The film formation method of the inorganic thin film layer constituting the laminate of the present invention is not particularly limited, and a known production method can be employed as long as the object of the present invention is not impaired. A vapor deposition method can be employed. For example, a vacuum deposition method, a sputtering method, a PVD method (physical vapor deposition method) such as ion blasting, or a CVD method (chemical vapor deposition method) can be used. A physical vapor deposition method is preferred, and a vacuum vapor deposition method is particularly preferred in terms of production speed and stability. As a heating method in the vacuum deposition method, resistance heating, high-frequency induction heating, electron beam heating, or the like can be used. As a reactive gas, oxygen, nitrogen, water vapor, or the like may be introduced, or reactive vapor deposition using means such as ozone addition or ion assist may be used. Also, the film forming conditions may be changed, such as applying a bias to the substrate, raising the substrate temperature, cooling the substrate, etc., as long as the object of the present invention is not compromised.

A method for forming an inorganic thin film layer by vacuum deposition will be described below. When the inorganic thin film layer is formed, the film made of the polyester resin layer constituting the present invention is conveyed to an inorganic thin film layer manufacturing apparatus via a metal roll. An example of the configuration of an inorganic thin film layer manufacturing apparatus includes an unwinding roll, a coating drum, a winding roll, an electron beam gun, a crucible, and a vacuum pump. The film is set on an unwinding roll, passes through a coating drum, and is wound up by a winding roll. The film pass line (in the inorganic thin film layer manufacturing equipment) is evacuated by a vacuum pump, and the inorganic material set in the crucible is evaporated by the beam emitted from the electron gun and deposited on the film passing through the coating drum. be. During the deposition of the inorganic material, the film is subjected to heat and tension between the unwind and take-up rolls. If the temperature applied to the film is too high, not only will the heat shrinkage of the film increase, but the softening will proceed, so that elongation deformation due to tension will easily occur. Furthermore, after the vapor deposition process, the temperature drop (cooling) of the film becomes large, the amount of shrinkage after expansion (different from thermal shrinkage) becomes large, cracks occur in the inorganic thin film layer, and the desired gas barrier property is exhibited. It is not preferable because it becomes difficult. On the other hand, the lower the temperature applied to the film, the better because the deformation of the film is suppressed. occur. The temperature applied to the film is preferably 100° C. or higher and 180° C. or lower, more preferably 110° C. or higher and 170° C. or lower, and even more preferably 120° C. or higher and 160° C. or lower. Also, if the tension applied to the film is too high, the film tends to be elongated and deformed, which is not preferable. On the other hand, if the tension applied to the film is too low, the heat shrinkage caused by heating the film cannot be suppressed, and the deformation also becomes large, which is not preferable. The tension per unit cross-sectional area (width x thickness) applied to the film is preferably 0.2 N/mm ² or more and 3 N/mm ² or less, and is 0.6 N/mm ² or more and 2.6 N/mm ² or less. More preferably, it is 1 N/mm ² or more and 2.2 N/mm ² or less.

5. Anchor Coat Layer In the laminate of the present invention, an anchor coat may be applied in advance to the resin layer serving as the base material before forming the inorganic thin film layer. By applying an anchor coat, the adhesion between the resin layer and the inorganic thin film layer is enhanced, and the gas barrier property of the laminate is further improved.

5.1. Types of Anchor Coat Layer The types of resins, cross-linking agents, compounds, etc. that constitute the anchor coat layer are not particularly limited. Combinations of polyvinyl acetal, polyester polyols, isocyanate compounds and silane coupling agents, mixtures of silicon compounds such as tetraethoxysilane and tetramethoxysilane or their hydrolysates and water-soluble polymers having hydroxyl groups, silicon-based A resin, a mixture of a polysilazane-based resin and a silane compound-based resin, or the like can be used.

5.2. Anchor Coat Layer Formation Conditions The method for forming the anchor coat layer is not particularly limited, and any known method can be employed. 4.1 above. An in-line coating method in which a coating process is provided during the film-forming process of the resin layer listed in "Polyester-based resin layer film-forming conditions", and an off-line coating method in which the film as the polyester-based resin layer of the present invention is wound as a roll and then coated. Either coating method may be used. In the off-line coating method, the in-line coating method is preferable because the productivity is inferior due to the fact that the resin film is wound up and then unwound by a separate device for coating. In the in-line coating method, the above 4.1. 4.1.2. described in "Polyester-based resin layer forming conditions". "first (longitudinal) stretching" or 4.1.3. Apply coating after "intermediate heat treatment", 4.1.4. "Second (horizontal) stretching" to 4.1.5. The solvent is dried until the "final heat treatment" (inside the tenter). Therefore, although the maximum temperature for drying the coating liquid depends on the final heat treatment temperature, a temperature of 65° C. or higher and 250° C. or lower is usually sufficient. The coating method is not particularly limited, and includes gravure coating, reverse coating, dipping, low coating, air knife coating, comma coating, screen printing, spray coating, gravure offset, die coating, and bar coating. etc., can be adopted.

6. Overcoat layer The laminate of the present invention is formed by forming the inorganic thin film layers listed in the above "4.2. Film formation conditions for the inorganic thin film layer", and aiming to improve scratch resistance and further gas barrier properties. An overcoat layer can also be provided as.
6.1. Types of overcoat layer The types of resins, cross-linking agents, compounds, etc. that constitute the overcoat layer are not particularly limited, but may be a composition comprising a urethane-based resin and a silane coupling agent, a compound comprising an organic silicon and its hydrolyzate, Conventionally known materials such as water-soluble polymers having hydroxyl groups or carboxyl groups, polyvinyl alcohol, and resins containing butenediol and vinyl alcohol can be used. It can be selected as appropriate.
In addition, one or more additives are added to the overcoat layer for the purpose of imparting antistatic properties, ultraviolet absorbency, coloration, thermal stability, slipperiness, etc., within the range that does not impair the object of the present invention. The type and amount of each additive can be appropriately selected according to the desired purpose.

6.2. Film Formation Method of Overcoat Layer When forming an overcoat layer, the laminate of the present invention is conveyed to coating equipment via a metal roll. Examples of equipment configuration include an unwinding roll, a coating process, a drying process, and a winding process. At the time of overcoating, the laminate set on the unwinding roll is passed through a metal roll through a coating process and a drying process, and finally led to a take-up roll. The coating method is not particularly limited, and gravure coating, reverse coating, dipping, low coating, air knife coating, comma coating, screen printing, spray coating, gravure offset, die coating, bar coating, etc. A conventionally known method can be employed, and can be appropriately selected according to the desired purpose. Among these, the gravure coating method, the reverse coating method, and the bar coating method are preferable from the viewpoint of productivity. As the drying method, one or a combination of two or more heating methods such as hot air drying, hot roll drying, high frequency irradiation, infrared irradiation, and UV irradiation can be used.

The drying process heats the laminate and also applies tension between metal rolls. If the temperature at which the laminate is heated in the drying process is too high, not only will the laminate undergo greater thermal shrinkage, but it will also soften, making it easier for stretching deformation due to tension to occur, and cracks will occur in the inorganic thin film layers of the laminate. more likely to occur. In addition, the temperature drop (cooling) of the laminate after leaving the drying process increases, and the amount of shrinkage after expansion (different from thermal contraction) increases accordingly, and cracks occur in the inorganic thin film layer and overcoat layer. It is not preferable because it becomes difficult to satisfy the desired gas barrier property. On the other hand, the lower the temperature at which the laminate is heated, the more preferable it is because deformation of the laminate is suppressed. The temperature at which the laminate is heated is preferably 60° C. or higher and 200° C. or lower, more preferably 80° C. or higher and 180° C. or lower, and even more preferably 100° C. or higher and 160° C. or lower. On the other hand, if the tension applied to the laminate is too high, the laminate tends to be elongated and deformed, which is not preferable. On the other hand, if the tension applied to the laminate is too low, the thermal shrinkage caused by heating the laminate cannot be suppressed, and the deformation also becomes large, which is not preferable. The tension per unit cross-sectional area (width x thickness) applied to the laminate is preferably 0.2 N/ ^mm2 or more and 3 N/ ^mm2 or less, and is 0.6 N/ ^mm2 or more and 2.6 N/ ^mm2 or less. and more preferably 1 N/mm ² or more and 2.2 N/mm ² or less.

7. Resin layers other than the polyester-based resin layer constituting the present invention, the laminate of the present invention, on the inorganic thin film layer listed in the above "4.2. film formation conditions of the inorganic thin film layer", "6. overcoat A resin layer (film) other than the polyester resin layer of the present invention is added to the outside of the laminate for the purpose of improving tensile strength, impact strength, flex resistance, etc. on the overcoat layer listed in "Layer". may be laminated.

7.1. Types of resin layers other than the polyester-based resin layer constituting the present invention The film as the resin layer other than the polyester-based resin layer constituting the present invention can be provided with any material such as polyamide-based, polyester-based, or polyolefin-based. can. Among these, it is preferable to use a polyamide-based film or a polyester-based film in order to improve the strength of the laminate. When another layer is provided, it is preferable to laminate it on a layer other than the heat-sealing layer, because there is a possibility that the predetermined heat-sealing strength cannot be satisfied if it is laminated on the heat-sealing layer. A method for laminating other layers will be described later.
Raw materials for polyamide films include, for example, polycapramide (nylon 6), polyhexamethylene adipamide (nylon 66), caprolactam/lauryllactam copolymer (nylon 6/12), caprolactam/hexamethylenediammonium adipate copolymer. coalescence (nylon 6/66), ethylene ammonium adipate/hexamethylenediammonium adipate/hexamethylenediammonium sebacate copolymer (nylon 6/66/610), polymer of meta-xylylenediamine and adipic acid (MXD-6) ), a hexamethylene isophthalamide/terephthalamide copolymer (amorphous nylon), or a mixed resin in which two or more of these are mixed. Also, an adhesion-improving layer can be provided on the surface of the film made of the resins listed above. Materials for the adhesion-improving layer include acrylic resins, water-soluble or water-dispersible polyester resins, and hydrophobic polyester resins obtained by graft copolymerization of acrylic resins.

As raw materials for the polyester film, the above 3.1.1. Polyethylene terephthalate can be preferably used in addition to the raw materials listed in "Types of polyester-based raw materials".
Examples of raw materials for polyolefin films include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene α-olefin copolymers, and the like. As the monomer, ethylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, octene-1 and the like can be used.
Polyamide-based films and polyolefin-based films can be produced by extruding these raw materials by a T-die method or an inflation method, followed by non-stretching, uniaxial stretching, or biaxial stretching.
The polyester-based film uses these raw materials as described in 4.1. It can be manufactured by the method mentioned in "Film forming conditions for the polyester-based resin layer".

7.2. A method for laminating a resin layer other than the polyester-based resin layer constituting the present invention As a method for bonding the laminate of the present invention to another film, a known method such as dry lamination, extrusion lamination, or heat sealing can be arbitrarily adopted. can do.
For dry lamination, commercially available dry lamination adhesives can be used. Representative examples include Dick Dry (registered trademark) LX-703VL manufactured by DIC, KR-90 manufactured by DIC, Takenate (registered trademark) A-4 manufactured by Mitsui Chemicals, Takelac (registered trademark) A-905 manufactured by Mitsui Chemicals. and so on.
In the case of extrusion lamination, polyethylene or the like is melted and adhered between layers or between a layer and another layer. It is also preferable to laminate an anchor coat layer in order to increase the adhesion of the surface of the layers. Representative examples of resins used for extrusion lamination include Novatec (registered trademark) LC600A manufactured by Nippon Polyethylene Co., Ltd., Sumikasen (registered trademark) L405-H manufactured by Sumitomo Chemical Co., Ltd., and Petrothene (registered trademark) 225 manufactured by Tosoh Corporation.

8. Configuration of package and bag-making method The laminate according to the present invention can be suitably used as a package. At least a part of the package may be composed of the laminate according to the present invention. etc. is improved, which is preferable. In addition, the package can have any layer structure including the laminate of the present invention. It is preferable that the heat-seal layer is the innermost surface (the surface in contact with the contents) of the package.
The method for making a bag having a laminate of the present invention is not particularly limited, and includes heat sealing using a heat bar (heat jaw), fusion sealing using a fusion cutting blade, adhesion using hot melt, and center sealing using a solvent. A conventionally known manufacturing method such as the above can be adopted.
A package having a laminate according to the present invention can be suitably used as a packaging material for various articles such as foods, medicines, and industrial products.

Next, the present invention will be specifically described using examples and comparative examples, but the present invention is not limited to the aspects of such examples, and can be changed as appropriate without departing from the spirit of the present invention. It is possible.

<Preparation of polyester raw material>
[Synthesis Example 1]
In a stainless steel autoclave equipped with a stirrer, thermometer and partial reflux condenser, 100 mol % dimethyl terephthalate (DMT) as the dicarboxylic acid component and 100 mol % ethylene glycol (EG) as the polyhydric alcohol component, Ethylene glycol was charged so that the molar ratio was 2.2 times that of dimethyl terephthalate, zinc acetate was used as a transesterification catalyst at 0.05 mol % (relative to the acid component), and the resulting methanol was distilled out of the system. The transesterification reaction was carried out while Then, 0.225 mol % of antimony trioxide (with respect to the acid component) is added as a polycondensation catalyst, and the polycondensation reaction is carried out under reduced pressure conditions of 26.7 Pa at 280° C., resulting in an intrinsic viscosity of 0.75 dl/g. A polyester (A) was obtained. This polyester (A) is polyethylene terephthalate. Table 1 shows the composition of polyester (A).

[Synthesis Example 2]
Polyesters (B) to (G) with different monomers were obtained in the same manner as in Synthesis Example 1. Table 1 shows the composition of each polyester. In Table 1, TPA is terephthalic acid, IPA is isophthalic acid, BD is 1,4-butanediol, NPG is neopentyl glycol, CHDM is 1,4-cyclohexanedimethanol, and DEG is diethylene glycol. In the production of polyester (G), SiO2 (Sylysia 266 manufactured by Fuji Silysia Co., Ltd.) was added as a lubricant at a rate of 7,000 ppm relative to the polyester. Each polyester was appropriately chipped. Table 1 shows the compositions of the polyesters (B) to (G).

[Example 1]
Polyester A, polyester B, polyester E, and polyester G were mixed at a mass ratio of 7:57:28:8 as raw materials for the seal layer (A layer), and polyester A, polyester B, and polyester were mixed as raw materials for the heat-resistant layer (B layer). E and Polyester G were mixed in a weight ratio of 52:34:6:8.
The mixed raw materials for the A layer and the B layer were put into separate screw extruders and melted at 270°C. Each molten resin was joined by a feed block in the middle of the flow path, discharged from a T-die, and cooled on a chill roll set to a surface temperature of 30° C. to obtain an unstretched laminated film. The flow path of the molten resin is set so that one side of the laminated film is the A layer and the other side is the B layer (two types of two layers, A layer and B layer), and the thickness ratio of the A layer and the B layer is 50/ The discharge amount was adjusted to 50.
The unstretched laminated film obtained by cooling and solidifying is guided to a longitudinal stretching machine in which a plurality of roll groups are continuously arranged, preheated on preheating rolls until the film temperature reaches 78 ° C., and then stretched 4.1 times. did. The film immediately after being longitudinally stretched was passed through a heating furnace set at 100° C. with a hot air heater, and subjected to a 20% relaxation treatment in the longitudinal direction using the speed difference between rolls at the entrance and exit of the heating furnace. After that, the longitudinally stretched film was forcibly cooled by cooling rolls whose surface temperature was set to 25°C.

The relaxed-treated film was guided to a transverse stretching machine (tenter), preheated for 5 seconds until the surface temperature reached 105° C., and then stretched 4.0 times in the width direction (horizontal direction). After the transverse stretching, the film was guided as it was to the intermediate zone and passed through for 1.0 second. In the intermediate zone of the tenter, hot air from the final heat treatment zone and the transverse stretching zone were applied so that when a strip of paper was suspended without the film passing through it, the strip of paper would hang almost completely in the vertical direction. blocked hot air from
After that, the film that passed through the intermediate zone was led to the final heat treatment zone and heat treated at 190° C. for 5 seconds. At this time, 3% relaxation treatment was performed in the width direction by narrowing the clip interval in the width direction of the film at the same time as performing the heat treatment. After passing through the final heat treatment zone, the film was cooled with cooling air at 30°C for 5 seconds. At this time, the film actual temperature at the exit of the tenter was 40°C. A biaxially oriented film having a thickness of 30 μm was continuously produced over a predetermined length by cutting off both edges and winding the film into a roll having a width of 600 mm to obtain a film roll.
On the heat-resistant layer side of the above film roll, aluminum is used as a vapor deposition source, and while oxygen gas is introduced by a vacuum vapor deposition machine, an aluminum oxide (AlOx) thin film is formed by a vacuum vapor deposition method to form a laminate continuously. It was produced to obtain a roll. The thickness of the inorganic thin film layer was 15 nm.
Metal rolls were provided at the entrance and the exit of the vapor deposition process, and the film was held by the metal rolls and passed through. The metal rolls were adjustable in speed by a drive motor, and tension was applied to the film by increasing the speed of the downstream rolls (draw) relative to the upstream side. The tension applied to the film was 1.7 N/mm ² (50 N in terms of width 1000 mm×thickness 30 μm).
The properties of the obtained laminate were evaluated by the evaluation methods described later. Table 2 shows manufacturing conditions and evaluation results.

[Examples 2 to 7]
In Examples 2 to 7, in the same manner as in Example 1, polyester films were formed by changing the mixing ratio of raw materials, the first stretching, the intermediate heat treatment, the second stretching, and the final heat treatment conditions, and then the inorganic thin film layer was formed. Rolls were obtained by continuously producing laminates with different types and thicknesses. Table 2 shows the manufacturing conditions and evaluation results of each laminate. In addition, the polyester resin layers of Examples 4 and 7 are sequentially biaxially stretched films in which the first stretching is in the horizontal direction and the second stretching is in the vertical direction, and the polyester resin layers of Examples 2 and 5 are in the vertical direction and the horizontal direction. (For Examples 2 and 5 in Table 2, the stretching conditions are listed in the first stretching and second stretching columns for convenience, but these are the same conditions and are simultaneously stretched. stretched).

[Comparative Example 1]
Polyester A, polyester B, polyester E, and polyester G were mixed at a mass ratio of 7:75:10:8 as raw materials for the sealing layer (A layer), and polyester A, polyester B, and polyester were mixed as raw materials for the heat-resistant layer (B layer). E and Polyester G were mixed in a weight ratio of 52:30:10:8.
The mixed raw materials for the A layer and the B layer were put into separate screw extruders and melted at 270°C. Each molten resin was joined by a feed block in the middle of the flow path, discharged from a T-die, and cooled on a chill roll set to a surface temperature of 30° C. to obtain an unstretched laminated film. In the laminated film, the molten resin flow path is set so that both sides of the outermost layer are the A layer and the intermediate layer is the B layer (two types of three layers, A layer / B layer / A layer). The discharge amount was adjusted so that the total layer thickness ratio was 50/50.
The unstretched laminated film obtained by cooling and solidifying was formed into a polyester film in the same manner as in Example 1, with the conditions of the first stretching, the intermediate heat treatment, the second stretching, and the final heat treatment changed, and then the inorganic thin film layer Rolls were obtained by continuously producing laminates in which the type was changed. The inorganic thin film layer was formed by vapor deposition on either one of the A layers. Table 2 shows the manufacturing conditions and evaluation results of the laminate of Comparative Example 1.

[Comparative Example 2]
In Comparative Example 2, in the same manner as in Example 1, a polyester film was formed by changing the mixing ratio of the raw materials, the first stretching, the intermediate heat treatment, the second stretching, and the final heat treatment conditions, and then the type of the inorganic thin film layer was changed. The resulting laminate was continuously produced to obtain a roll. Table 2 shows the manufacturing conditions and evaluation results of the laminate of Comparative Example 2.

[Comparative Example 3]
In Comparative Example 3, after forming the same polyester film as in Example 1, a roll was obtained by continuously producing (only a polyester film consisting of a heat seal layer and a heat-resistant layer) without providing an inorganic thin film layer. . Table 2 shows the production conditions and evaluation results of the film of Comparative Example 3.

[Comparative Example 4]
For the film of Comparative Example 4, LIX film (linear low density polyethylene film, registered trademark) L4103-30 μm manufactured by Toyobo Co., Ltd. was used. On one side of this film, aluminum oxide (AlOx) thin film was formed by a vacuum deposition method while introducing oxygen gas with a vacuum deposition machine, using aluminum as a deposition source, to continuously fabricate a laminate. Got a roll. The thickness of the inorganic thin film layer was 15 nm. Table 2 shows the manufacturing conditions and evaluation results of the laminate of Comparative Example 4.

<Evaluation method for laminate>
The evaluation method of the laminate is as follows. In addition, when the longitudinal direction and the width direction cannot be immediately specified for reasons such as a small area of the laminate, it is sufficient to temporarily determine the longitudinal direction and the width direction and measure, and the tentatively determined longitudinal direction and the width direction are true directions. There is no particular problem even if it is 90 degrees different from .

[Heat seal strength]
The heat seal strength was measured according to JIS Z1707. Show specific steps. A heat sealer was used to bond the heat-sealed surfaces of the samples together. The heat sealing conditions were an upper bar temperature of 140° C., a lower bar temperature of 30° C., a pressure of 0.2 MPa, and a time of 2 seconds. The adhesive sample was cut so that the seal width was 15 mm. The peel strength was measured using a universal tensile tester "DSS-100" (manufactured by Shimadzu Corporation) at a tensile speed of 200 mm/min. The peel strength is expressed as strength per 15 mm (N/15 mm).

[Deformation rate when tension is applied]
A sample having a size of 30 mm in the longitudinal direction and 4 mm in the width direction was cut out and measured using a thermomechanical analyzer (TMA, manufactured by Seiko Instruments Inc.). The chuck-to-chuck distance was set to 20 mm, and the sample was attached to the probe using a dedicated chuck. After setting the sample, the tension was kept constant at 1.7 N/mm ² (approximately 200 mN in terms of width 4 mm x thickness 30 μm), and the furnace temperature was raised from 30° C. to 160° C. at a rate of 10° C./min. minutes and cooled from 160° C. to 30° C. at 10° C./min. The deformation rate obtained by this measurement was recorded during heating from 30°C to 140°C and during cooling from 160°C to 30°C. The heat deformation rate from 30° C. to 140° C. and the cooling deformation rate from 160° C. to 30° C. were calculated according to the following formulas 1 and 2, respectively. Regarding the deformation rate, a positive value indicates elongation of the film, and a negative value indicates shrinkage of the film.

Heat deformation rate = [{length before heating (30 ° C.) - length after heating (140 ° C.)} / length before heating (30 ° C.)] × 100 (%) Equation 1
Cooling deformation rate = [{length before cooling (160 ° C.) - length after cooling (30 ° C.)} / length before cooling (160 ° C.)] × 100 (%) Equation 2

[Gas barrier property]
The water vapor permeability and the oxygen permeability were evaluated as gas barrier properties by the following methods.
Water vapor permeability was measured according to JIS K7126 B method. Humidity-conditioned gas permeates from the sealing layer side of the laminate to the inorganic thin film layer side in an atmosphere with a temperature of 40 ° C. and a humidity of 90% RH using a water vapor transmission rate measuring device (PERMATRAN-W3/33MG MOCON). The water vapor transmission rate was measured in the direction.
Oxygen permeability was measured according to JIS K7126-2 method. Using an oxygen permeation measurement device (OX-TRAN 2/20 manufactured by MOCOM), in an atmosphere of 23 degrees Celsius and 65% RH, the direction in which oxygen permeates from the seal layer side of the laminate to the inorganic thin film layer side. Oxygen permeability was measured at
Before measuring the water vapor transmission rate and the oxygen transmission rate, each sample was allowed to stand for 4 hours in an environment with a humidity of 65% RH to adjust the humidity.
The obtained results of water vapor permeability and oxygen permeability were evaluated according to the following criteria.

Judgment ○
Determination of water vapor permeability of 4 [g/(m ² d)] or less and oxygen permeability of 4 [cc/(m ² d atm)] or less ×
Water vapor transmission rate is greater than 4 [g/(m ² · d)] or oxygen transmission rate is greater than 4 [cc/(m ² · d · atm)]

[Warm water heat shrinkage]
Cut the sample into a square of 10 cm × 10 cm, immerse it in warm water at 98 ± 0.5 ° C. for 3 minutes without load and shrink it, then immerse it in water at 25 ° C. ± 0.5 ° C. for 10 seconds, out of the water. After that, the vertical and horizontal dimensions of the sample were measured, and the heat shrinkage rate in each direction was obtained according to the following formula 3. In addition, the measurement was performed twice and the average value was obtained.

Thermal shrinkage = {(length before shrinkage - length after shrinkage) / length before shrinkage} x 100 (%) Formula 3

The thermal shrinkage rate in the longitudinal and transverse directions was evaluated according to the following criteria. Judgment criteria are as follows.

Judgment ○ Heat shrinkage rate 5% or less Judgment × Heat shrinkage rate greater than 5%

[Adsorption]
The laminate was cut into a square of 10 cm×10 cm, two sheets were stacked with the heat-sealed surface facing inward, and the position 1 cm from the end of the film was heat-sealed to prepare a bag. An aluminum cup containing 0.5 ml of the content was placed in the bag, and the bag was closed and hermetically sealed by heat-sealing the position 1 cm from the edge of the laminate. D-limonene (manufactured by Tokyo Chemical Industry Co., Ltd.) and L-menthol (manufactured by Nacalai Tesque Co., Ltd.) were used as the contents. After holding for 20 hours in a 30°C environment, a 5 cm x 5 cm square was cut from the surface of the film bag in contact with the mouth of the aluminum cup, and the cut film was immersed in 4 ml of extraction solvent and extracted with ultrasonic waves for 30 minutes. did. 99.8% ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was used as an extraction solvent. A gas chromatograph "GC-14B" manufactured by Shimadzu Corporation was used to quantify the concentration of the contents in the extraction solution. The gas chromatograph uses "GC-14A Glass ID 2.6φ x 1.1m PET-HT 5% Uniport HP 80/100 (manufactured by GL Sciences)" as the column, FID as the detector, and _N2 as the carrier gas. , a carrier gas flow rate of 35 ml/min, and an injection amount of 1 μl. The amount of adsorption was indicated by the amount of adsorption (μg/cm ² ) per 1 cm ² of the heat-sealed surface, and the low adsorptivity was judged as follows.
Judgment ○ 0 μg/cm ² or more, less than 2 μg/cm ² Judgment △ 2 μg/cm ² or more, less than 10 μg/cm ² Judgment × 10 μg/cm ² or more

<Lamination of overcoat layer>
[Conditions]
Materials A to D shown below were mixed in the proportions shown in Table 3 to prepare an overcoat solution.
A: Aqueous dispersion of aqueous polyurethane resin B: Tetraethoxysilane hydrolyzed solution C: Polyvinyl alcohol D: Butenediol/vinyl alcohol copolymer

[Deposition method]
The laminate is unwound from the roll on which the laminate was taken up, and the mixture shown in Table 3 is applied on the inorganic thin film layer (if there is no inorganic thin film layer, on the heat-resistant layer side) to form an overcoat layer. set continuously. Specifically, the prepared liquid was applied with a bar coater and led to a drying furnace set at a temperature of 120° C. and a wind speed of 15 m/sec to continuously form an overcoat layer. Metal rolls were provided at the entrance and the exit of the drying oven, and the film was held by the metal rolls and passed through. The metal rolls were adjustable in speed by a drive motor, and tension was applied to the film by increasing the speed of the downstream rolls (draw) relative to the upstream side. The tension applied to the film was 1.7 N/mm ² (50 N in terms of width 1000 mm×thickness 30 μm). In the laminate of the present invention, since it is necessary to be able to adapt to high tension during secondary processing as a laminate for secondary processing, the tension is set to be high.

<Method for evaluating overcoat layer laminate>
[Gas barrier property]
The gas barrier properties were evaluated by the same method as the evaluation method for [Gas barrier properties] described in <Evaluation method for laminate> above.

[Heat seal strength]
The 140° C. heat seal strength was evaluated by the same method as the evaluation method for [heat seal strength] described in the above <Evaluation method for laminate>.

[Adsorption]
Adsorption to limonene and menthol was evaluated by the same method as the evaluation method for [Absorptivity] described in <Evaluation method for laminate> above.
Table 3 shows the evaluation results of the obtained overcoat layer laminate.

[Evaluation result of laminate]
From Tables 2 and 3, all of the laminates of Examples 1 to 7 satisfy heat seal strength, deformation rate when tension is applied, gas barrier property, heat shrinkage rate, and adsorption property, and the overcoat layer is laminated. The gas barrier property was excellent even when
On the other hand, since the laminate of Comparative Example 1 had a large deformation rate when tension was applied, the gas barrier property was low even when the overcoat layer was laminated. Therefore, it was unsuitable as a laminate for secondary processing.
The laminate of Comparative Example 2 was unsuitable as a sealant because the heat seal strength was zero.
Since the film of Comparative Example 3 did not have an inorganic thin film layer, the result was inferior in gas barrier properties.
Since the laminate of Comparative Example 4 had a large deformation rate when tension was applied, the gas barrier property was low even when the overcoat layer was laminated. Furthermore, not only the heat seal strength was low, but also the adsorption of limonene and menthol was inferior, so it was not suitable as a sealant with low adsorption.

1 Unwinding roll 2 Laminated body (arrow indicates flow direction)
3 coating drum 4 take-up roll 5 electron gun 6 vapor deposition material 7 electron beam 8 vapor deposition particles 9 vacuum pump

Claims (5)

A laminate having at least one layer each of a heat-sealing layer, a heat-resistant layer, and an inorganic thin film layer, wherein each of the heat-sealing layer and the heat-resistant layer is formed of polyester containing ethylene terephthalate as a main constituent, As a component constituting each polyester constituting each layer, one or more of neopentyl glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol, and diethylene glycol are included as diol monomer components other than ethylene glycol, A laminate characterized by satisfying the following requirements (1) to (5).
(1) The seal strength when the heat seal layers are sealed at 140 ° C., 0.2 MPa, 2 seconds is 8 N / 15 mm or more and 30 N / 15 mm or less (2) Temperature 40 ° C., relative humidity 90% RH environment water vapor Permeability of 0.05 [g/(m2 d)] or more and 4 [g/(m2 d)] or less (3) Oxygen permeability of 0.05 at a temperature of 23°C and a relative humidity of 65% RH [cc/(m2・d・atm)] or more and 4 [cc/(m2・d・atm)] or less (4) While applying a tension of 1.7 N/mm2 per unit cross-sectional area by thermal mechanical analysis (TMA) , The deformation rate in the longitudinal direction is 0% or more and 10% or less when the temperature is increased from 30 ° C. to 140 ° C. at 10 ° C./min. /mm2, the temperature is increased from 30°C to 160°C at a rate of 10°C/min, held at 160°C for 1 minute, and then cooled from 160°C to 30°C at a rate of 10°C/min. Deformation rate in the longitudinal direction is -2% to 0% (negative value indicates shrinkage) 2. The laminate according to claim 1, wherein isophthalic acid is included as an acid component other than terephthalic acid as a component constituting each polyester constituting the heat seal layer or the heat resistant layer. Among all monomer components of each polyester component constituting the heat-sealing layer and the heat-resistant layer, a diol monomer component other than the ethylene glycol is contained, and the content of the diol monomer component satisfies the following (1) to (3). The laminate according to claim 2, characterized in that:
(1) 30 mol% or more and 50 mol% or less in the heat seal layer (2) 9 mol% or more and 20 mol% or less in the heat-resistant layer (3) The content difference between the heat seal layer and the heat-resistant layer is 20 mol% or more and 35 mol% or less 4. The laminate according to any one of claims 1 to 3, further comprising an overcoat layer. A package comprising at least a part of the laminate according to any one of claims 1 to 4.

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