WO2020138048A1

WO2020138048A1 - Layered product and packaging body obtained using same

Info

Publication number: WO2020138048A1
Application number: PCT/JP2019/050547
Authority: WO
Inventors: 慎太郎石丸; 雅幸春田; 智章早田
Original assignee: 東洋紡株式会社
Priority date: 2018-12-28
Filing date: 2019-12-24
Publication date: 2020-07-02
Also published as: TW202043046A; JPWO2020138048A1

Abstract

[Problem] To provide: a layered product in which adsorption of an enclosed component is low and which exhibits high heat sealing strength at low temperatures and excellent bursting resistance; and a packaging body containing the layered product as at least one layer thereof. [Solution] This layered product is obtained by layering at least a substrate layer, an adhesive layer and a sealant layer in that order. The substrate layer comprises a polyester, which contains poly(ethylene terephthalate) or poly(butylene terephthalate) as a primary constituent component, a polyolefin that contains polypropylene as a primary constituent component, or a polyamide that contains a nylon as a primary constituent component. The sealant layer comprises a polyester that contains poly(ethylene terephthalate) as a primary constituent component. When sealant layers are sealed for 2 seconds at a temperature of 140ºC and a pressure of 0.2 MPa, the sealing strength of the layered product is 8 N/15 mm-70 N/15 mm.

Description

Laminated body and package using the same

The present invention relates to a laminate excellent in heat sealability and bag breakage resistance, and a package using the same.

BACKGROUND ART Conventionally, a laminated film obtained by heat-sealing or laminating a sealant film has been used as a packaging material such as a packaging body or a lid material in many distribution items represented by foods, pharmaceuticals, and industrial products. The innermost surface of the packaging material (the surface in contact with the contents) is provided with a sealant layer made of a polyolefin resin such as polyethylene or polypropylene having high sealing strength, or a copolymer resin such as ionomer or EMMA. It is known that these resins can achieve high adhesion strength by heat sealing.
However, a non-stretched sealant film made of a polyolefin-based resin as described in Patent Document 1 easily adsorbs components made of organic compounds such as fats and oils and fragrances, so that it is easy to change the scent and taste of the contents. Has a drawback. Therefore, it is often not suitable to use the sealant layer made of a polyolefin resin as the innermost layer for packaging of chemical products, pharmaceuticals, foods and the like.

On the other hand, a sealant composed of an acrylonitrile-based resin as described in Patent Document 2 is suitable for use as the innermost layer of a packaging material because it hardly adsorbs organic compounds contained in chemical products, pharmaceuticals, foods and the like. There is. However, the acrylonitrile film has a problem that the heat seal strength is low 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 bag making line has been accelerated, and it is preferable that the sealing temperature is low to meet this requirement. A sealant composed of an acrylonitrile resin does not satisfy these requirements.

In view of these problems, Patent Document 3 discloses a polyester-based sealant having a non-adsorbing property for organic compounds and a low-temperature sealing property. However, the sealant of Patent Document 3 has a problem that the heat generated during heat sealing not only causes heat shrinkage but also melts the sealant to form holes. For example, when a package using a sealant is manufactured, the shape of the bag is not only collapsed when the sealant is thermally shrunk, but also when the sealant is perforated, the bag cannot be preserved, which is not preferable. Thus, the sealant of Patent Document 3 had room for improvement in heat resistance.

Therefore, Patent Document 4 discloses a sealant with improved heat resistance. The sealant described in Patent Document 4 has a heat-sealable layer and a layer other than the heat-sealable layer, and separately controls the thermal properties of these layers to satisfy the heat-sealability and heat resistance. However, when the sealant described in Patent Document 4 is used as the sealant that constitutes the liquid or heavy-weight package, there is a problem that the bag is broken when the package falls. In addition, the package using the sealant described in Patent Document 4 has a problem that a hole is easily pierced when it is pierced from the outside or the content has corners.

In order to solve such a problem, for example, Patent Document 5 discloses a heat-sealable biaxially stretched polyester film containing 60% by weight or more of polybutylene terephthalate. Although the film of Patent Document 5 has improved puncture strength as compared with the conventional polyester-based film, it does not exhibit heat seal strength unless the temperature is 230° C., and thus has a problem that heat shrinkage at the time of sealing becomes large. There is.

Japanese Patent No. 3817846 JP-A-7-132946 International Publication No. 2014-175313 International publication WO2018/150997 JP, 2016-203630, A

The present invention aims to solve the above-mentioned problems of the prior art. That is, an object of the present invention is to provide a laminate which has less component adsorption of contents, has high heat seal strength in a low temperature range, and has excellent bag-breaking resistance. At the same time, an object of the present invention is to provide a package including the above-mentioned laminated body as at least one layer.

The present invention has the following configurations.
1. At least three layers of base material layer/adhesive layer/sealant layer are laminated in this order,
The base material layer is made of polyester having polyethylene terephthalate or polybutylene terephthalate as a main constituent, or polyolefin having polypropylene as a main constituent, or polyamide having nylon as a main constituent, and the sealant layer is mainly composed of polyethylene terephthalate. A laminate, which is composed of polyethylene as a component and has a seal strength of 8 N/15 mm or more and 70 N/15 mm or less when the sealant layers are sealed at 140° C., 0.2 MPa, and 2 seconds.
2. 1. The base material layer is made of polyester having polyethylene terephthalate or polybutylene terephthalate as a main constituent. The laminated body according to.
3. Further, a gas barrier layer is laminated, which is characterized in that Or 2. The laminate according to any one of the above.
4. 1. The puncture strength is 0.4 N/μm or more and 0.6 N/μm or less. ~3. The laminated body according to any one of 1.
5. As a monomer component of the polyester component constituting the sealant layer, a diol monomer component other than ethylene glycol and/or an acid component other than terephthalic acid is contained, and the diol component is neopentyl glycol, 1,4-cyclohexanedimethanol, 1. One or more selected from the group consisting of 1,4-butanediol and diethylene glycol, wherein the acid component is isophthalic acid. ~ 4. The laminated body according to any one of 1.
6. The above 1. ~ 5. A package having at least one layer of the laminate according to any one of 1.

The laminate of the present invention has little adsorption of the components of the contents, has a high heat seal strength in a low temperature range, and has excellent bag-breaking resistance. Therefore, when used as a packaging material, high sealing strength can be exhibited, and the function of protecting the contents from falling and external stimuli can be improved.

In the present invention, at least three layers of a base material layer/adhesive layer/sealant layer are laminated in this order, and the base material layer is a main constituent component of polyester or polypropylene whose main constituent component is polyethylene terephthalate or polybutylene terephthalate. And a polyamide containing nylon as a main constituent, the sealant layer is made of polyethylene containing polyethylene terephthalate as a main constituent, and the sealant layers are sealed at 140° C., 0.2 MPa for 2 seconds. The laminate has a seal strength of 8 N/15 mm or more and 70 N/15 mm or less.

The laminate of the present invention will be described below.
1. Layer structure of laminate, thickness, layer ratio The laminate of the present invention has at least each layer of a heat seal layer (which may be referred to as a sealant layer) and a base material in order to achieve both heat sealability and bag breakage resistance. It must have one layer at a time and must have at least three layers with an adhesive layer to stack these at least two layers. Furthermore, in order to satisfy the predetermined heat seal strength, the heat seal layer must be provided on either one of the outermost layers of the laminate. The base material may be located on either the outermost layer or the intermediate layer (in the case of 4 layers or more) of the laminate. In other words, the base material layer/adhesive layer/heat seal layer must be laminated in this order from the outermost layer when the present invention is used as a package.

The layer structure of the laminate of the invention is preferably a four-layer structure in which a gas barrier layer is provided in addition to the above-mentioned three layers. The gas barrier layer is preferably composed of an inorganic thin film containing a metal or a metal oxide as a main constituent, and may be located in either the outermost layer or the intermediate layer. More preferably, the gas barrier layer is transparent.

In addition, the laminate of the present invention may be provided with a printing layer on which characters and patterns are described in order to improve the design as a package. As a material for forming the printing layer, known materials such as gravure printing ink and flexographic printing ink can be used. The number of printing layers may be one or plural. In order to print with a plurality of colors to improve the design, it is preferable to have a printing layer including a plurality of layers. The printing layer may be located on either the outermost layer or the intermediate layer.

As a preferred constitution of the present invention, from the outermost layer when used as a package, the base material layer/printing layer/adhesive layer/sealant layer, or the base material layer/gas barrier layer/printing layer/adhesive layer/sealant layer, or Examples include base material layer/gas barrier layer/adhesive layer/sealant layer.
The constituent requirements for each layer will be described later.

Further, the laminate of the present invention may further include an anchor coat layer laminated on the base material layer or the sealant layer and an overcoat layer laminated on the gas barrier layer, if necessary. By providing these layers, the gas barrier property and scratch resistance of the laminate can be improved.

The thickness of the laminate 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 be difficult, which is not preferable. The thickness of the laminated body may be thicker than 200 μm, but this is not preferable because the weight used for the laminated body increases and the 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.

The layer 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 will be reduced, which is not preferable. When the layer ratio of the heat-sealing layer is higher than 80%, the heat-sealing property of the laminate is improved, but the heat resistance is deteriorated, which is not preferable. The layer ratio of the heat seal layer is more preferably 30% or more and 70% or less.

The layer ratio of the base material layer to the total thickness of the laminate is preferably 20% or more and 80% or less. When the layer ratio of the base material layer is less than 20%, the bag-breaking resistance of the package is reduced, which is not preferable. When the layer ratio of the base material layer is higher than 80%, the bag breaking resistance when a packaging bag is produced from the laminate is improved, but the thickness of the heat seal layer is relatively reduced, which is not preferable. The base material layer ratio is more preferably 30% or more and 70% or less.

The thickness of the gas barrier layer is preferably 2 nm or more and 100 nm or less when the inorganic thin film layer is used as the gas barrier layer and the inorganic thin film layer is made of vapor-deposited metal or vapor-deposited metal oxide. If the thickness of this layer is less than 2 nm, the gas barrier property tends to deteriorate, which is not preferable. On the other hand, even if the thickness of this layer exceeds 100 nm, there is no corresponding effect of improving the gas barrier property 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 further preferably 8 nm or more and 94 nm or less.

When the gas barrier layer is a metal foil, the thickness of the metal foil is preferably 3 μm or more and 200 μm or less. If the thickness of this layer is less than 3 μm, the gas barrier property tends to deteriorate, which is not preferable. On the other hand, even if the thickness of this layer exceeds 200 nm, there is no corresponding effect of improving the gas barrier property and the manufacturing cost increases, which is not preferable. The thickness of the inorganic thin film layer (metal foil) is more preferably 5 μm or more and 197 μm or less, and further preferably 8 μm or more and 194 μm or less.

In addition, the outermost layer (including the heat-sealing layer) of the laminate of the present invention is provided with a layer that has been subjected to corona treatment, coating treatment, flame treatment or the like in order to improve the printability and slipperiness of the film surface. It is also possible and can be arbitrarily provided within the range not deviating from the requirements of the present invention.

2. Characteristics of laminated body 2.1. Heat-sealing strength The heat-sealing strength when heat-sealing the heat-sealing layers of the laminate of the present invention at a temperature of 140° C., a seal bar pressure of 0.2 MPa and a sealing time of 2 seconds is required to be 8 N/15 mm or more and 70 N/15 mm or less. There is.
If the heat-sealing strength is less than 8 N/15 mm, the sealed portion can be easily peeled off by boil treatment or the like, so that it cannot be used as a package. The heat seal strength is preferably 12 N/15 mm or more, more preferably 14 N/15 mm or more. The heat seal strength is preferably high, but the currently obtained upper limit is about 60 N/15 mm. Even if the upper limit of the heat seal strength is 69 N/15 mm, it can be said that it is sufficiently preferable in practical use.

2.2. Impact Strength The laminate of the present invention preferably has an impact strength of 0.9 J or more and 3.0 J or less. If the impact strength is less than 0.9 J, the laminated body is easily broken when dropped as a package, which is not preferable. The lower limit of impact strength is more preferably 1 J, and even more preferably 1.1 J. On the other hand, the higher the impact strength is, the more preferable, but 3.0 J is the upper limit in the technical level of the present invention. Even if the upper limit of impact strength is 2.9 J, it can be said that it is sufficiently preferable in practical use.

2.3. Puncture Strength The laminate of the present invention preferably has a puncture strength of 0.4 N/μm or more and 0.6 N/μm or less. When the puncture strength is less than 0.4 N/μm, when the laminate is used as a package, it is easily pierced by external puncture or when the contents have corners, which is not preferable. The lower limit of the puncture strength is more preferably 0.42 N/μm and even more preferably 0.44 N/μm. On the other hand, the higher the puncture strength, the more preferable, but in the technical level of the present invention, the upper limit is 0.6 N/μm. Even if the upper limit of the puncture strength is 0.59 N/μm, it can be said that it is sufficiently preferable in practical use.

2.4. Heat Shrinkage Rate The laminate of the present invention preferably has a hot water heat shrinkage rate in the width direction and the longitudinal direction of -5% or more and 5% or less when treated in hot water of 98°C for 3 minutes. When the hot water heat shrinkage rate exceeds 5%, when the bag produced by using the laminate is subjected to heat treatment such as retort treatment, the bag is largely deformed and the original shape cannot be maintained, and the inorganic substance is not only retained. It is not preferable because cracks occur in the layer made of and the gas barrier property is deteriorated. The hot water heat shrinkage is more preferably 4% or less, and further preferably 3% or less. On the other hand, when the hot water heat shrinkage rate is less than -5%, it means that the laminate is stretched, which is not preferable because it is difficult to maintain the original shape of the bag as in the case where the shrinkage rate is high. The hot water heat shrinkage of the laminate is more preferably -4% or more and 4% or less, and further preferably -3% or more and 3% or less.

2.5. Types of Contents and Adsorption Amount The laminate of the present invention is characterized by being less likely to adsorb organic compounds contained in chemical products, pharmaceuticals, foods and the like. Usually, when using the laminate as a package, since the heat-sealing layer is the innermost layer, the adsorption amount of the laminate of the present invention described in this section means the amount by which the heat-sealing layer adsorbs the contents. Show.

Examples of the organic compound include d-limonene, citral, citronellal, p-menthane, pinene, terpinene, myrcene, karen, geraniol, nerol, citronellal, terpineol, 1-menthol, nerolidol, borneol, dl-camphor, lycopene. , Carotene, trans-2-hexenal, cis-3-hexenol, β-ionone, serinene, 1-octen-3-ol, benzyl alcohol, octal tulobuterol hydrochloride, tocopherol acetate, etc. ..

The amount adsorbed to the laminate varies depending on the adsorbing conditions (concentration of adsorbing substance, storage period, temperature, etc.), but the adsorbing amount when stored for 1 week according to the method described below is 0 μg/cm ² or more and 2 μg/ It is preferably cm ² . An adsorption amount of 0 μg/cm ² indicates that the content is not adsorbed on the sealant at all. Adsorption amount is more preferable to be 1.8μg / cm ² or less and further preferably 1.6 [mu] g / cm ² or less.

Since the laminate of the present invention has the heat-sealing layer made of a polyester-based component, the adsorptivity may be increased for organic compounds having a similar chemical structure. Specifically, since the polyester resin that constitutes the sealant has four oxygen atoms in the repeating units of the constituent components, the chemical structure of the organic compound shows that the higher the number of oxygen atoms (closer to four), the more the sealant is added to the sealant. The solubility of the organic compound tends to increase and the adsorptivity tends to increase. For example, packaging a content containing eugenol having two oxygen atoms or methyl salicylate having three oxygen atoms is not preferable because the adsorption amount easily exceeds 2 μg/cm 2.

3. Raw materials constituting the laminate 3.1. Heat Seal Layer The raw material species of the heat seal layer constituting the laminate of the present invention has an ethylene terephthalate unit as a main constituent component. Here, “to be the main constituent” means that the content of all constituents is 50 mol% or more, based on 100 mol %.

Further, it is preferable that the polyester used in the polyester resin layer of the present invention contains at least one component other than ethylene terephthalate. This is because the presence of a component other than ethylene terephthalate improves the heat seal strength of the heat seal layer. In the heat-resistant layer, it is preferable that the components other than ethylene terephthalate are small, but by including the components other than ethylene terephthalate, it is possible to reduce the difference in shrinkage ratio with the heat seal layer, and to reduce the curl of the laminate. There is. The content of each component differs between the heat seal layer and the heat resistant layer, and will be described later. Examples of the dicarboxylic acid monomer that can be a component other than terephthalic acid that constitutes ethylene terephthalate include aromatic dicarboxylic acids such as isophthalic acid, 1,4-cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, orthophthalic acid, adipic acid, Aliphatic dicarboxylic acids such as azelaic acid, sebacic acid, decanedicarboxylic acid, and alicyclic dicarboxylic acids are included. Among the above carboxylic acid components, the use of isophthalic acid is preferable because the heat seal strength between the heat seal layers can easily be 8 N/15 mm or more. However, it is preferable that a polyvalent carboxylic acid having a valence of 3 or more (for example, trimellitic acid, pyromellitic acid and their anhydrides) is not contained in the polyester.

Examples of the diol monomer which can be a component 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 thereof include long-chain diols such as butanediol, aliphatic diols such as hexanediol, and aromatic diols such as bisphenol A. However, the polyester may not contain a diol having 8 or more carbon atoms (for example, octane diol) or a polyhydric alcohol having 3 or more valences (for example, trimethylolpropane, trimethylolethane, glycerin, diglycerin). preferable.
Further, a polyester elastomer containing ε-caprolactone, tetramethylene glycol or the like may be contained as a component constituting the polyester. Since the polyester elastomer has the effect of lowering the melting point of the polyester resin layer, it can be particularly preferably used for the heat seal layer.

Among these, by using at least one of neopentyl glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol and diethylene glycol, the heat-sealing strength between the heat-sealing layers can easily be 8 N/15 mm or more. Therefore, it is preferable. It is more preferable to use at least one of neopentyl glycol and 1,4-cyclohexanedimethanol, and it is particularly preferable to use neopentyl glycol.
The polyester used for the heat-sealing layer constituting the laminate of the present invention has a content of dicarboxylic acid monomer and/or diol monomer, which is a component other than terephthalic acid and ethylene glycol constituting ethylene terephthalate, of 25 mol% or more. Is preferable, 27 mol% or more is more preferable, and 29 mol% or more is particularly preferable. Further, the upper limit of the content of monomers other than ethylene terephthalate is 50 mol %.
When the monomer other than ethylene terephthalate contained in the heat seal layer is lower than 25 mol%, even if the molten resin is extruded from the die and rapidly solidified, it will be crystallized in the subsequent stretching and heat setting steps. Therefore, it becomes difficult to set the heat sealing strength to 8 N/15 mm or more, which is not preferable.

On the other hand, when the monomer other than ethylene terephthalate contained in the heat seal layer is 50 mol% or more, the heat seal strength of the film can be increased, but the heat resistance of the heat seal layer becomes extremely low. Therefore, when heat sealing is performed, the periphery of the sealing portion is blocked (a phenomenon in which the heat conduction from the heating member causes sealing in a wider range than the intended range), which makes proper heat sealing difficult. .. The content of the monomer other than ethylene terephthalate is more preferably 48 mol% or less, and particularly preferably 46% or less.

3.2. Base Material Layer The base material layer constituting the present invention is a polyolefin or nylon (nylon 4.6, nylon 6, nylon 6.6, nylon 6,6, whose main component is polyethylene terephthalate or polybutylene terephthalate). It is preferably a uniaxially stretched film or a biaxially stretched film, which is composed of a polyamide containing at least one selected from nylon 12 as a main constituent. Commercially available products may be used, for example, ester (registered trademark) ester film E5102 manufactured by Toyobo, Espet films T4100 and T6140 manufactured by Toyobo, Harden (registered trademark) films N1100, N2100 manufactured by Toyobo, and pyrene manufactured by Toyobo. (Registered trademark) films P2261, P2161 and the like. Further, a film containing polybutylene terephthalate as a main constituent may be used as the base material layer. In recent years, there has been a growing awareness of "monomaterialization" that seeks to unify the constituent materials of the package to improve the efficiency of plastic recycling. Therefore, the base material layer is the same polyester resin as the heat seal layer. preferable. Specifically, it is preferable to use polybutylene terephthalate or polyethylene terephthalate as a main constituent, and it is more preferable that the main constituent is polybutylene terephthalate. Below, the description when using a polyester resin for a base material layer is described.

The content of the polybutylene terephthalate or polyethylene terephthalate resin contained in the base material layer is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more. If it is less than 60 mol %, the impact strength and the puncture strength of the laminate may decrease.
In polybutylene terephthalate, terephthalic acid as a dicarboxylic acid component is preferably 90 mol% or more, more preferably 95 mol% or more, still more preferably 98 mol% or more, and most preferably 100 mol%. As the glycol component, 1,4-butanediol is preferably 90 mol% or more, more preferably 95 mol% or more, further preferably 97 mol% or more, and most preferably 1,4-butane at the time of polymerization. It means that it does not contain other than by-products generated by ether bond of diol.

In the polyethylene terephthalate, terephthalic acid as a dicarboxylic acid component is preferably 90 mol% or more, more preferably 95 mol% or more, further preferably 98 mol% or more, and most preferably 100 mol%. As the glycol component, ethylene glycol is preferably 90 mol% or more, more preferably 95 mol% or more, still more preferably 97 mol% or more, and most preferably diethylene glycol which is a by-product at the time of polymerization. That is, the content is less than or equal to mol %.
The base material layer used in the present invention may contain a polyester resin other than polybutylene terephthalate or polyethylene terephthalate for the purpose of adjusting film-forming properties and mechanical properties of the laminate during biaxial stretching.

Examples of polyester resins other than the above two are polyester resins such as polyethylene naphthalate, polybutylene naphthalate and polypropylene terephthalate, as well as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid and azelaine. Polyester resin copolymerized with dicarboxylic acid such as acid and sebacic acid, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexane Examples thereof include polyester resins obtained by copolymerizing diol components such as diol, diethylene glycol, cyclohexane diol, polyethylene glycol, polytetramethylene glycol, and polycarbonate diol. However, those containing polyalkylene oxide are not suitable.

The upper limit of the amount of the polyester resin added is preferably 40 mol% or less, more preferably 30 mol% or less, further preferably 10 mol% or less, and particularly preferably 5 mol% or less. If the amount of the polyester resin added exceeds 40 mol %, the impact strength and the puncture strength of the laminate will be insufficient, and the gas barrier property may deteriorate.

In the heat-sealing layer constituting the laminate of the present invention, in the base material layer, if necessary, various additives, for example, waxes, antioxidants, antistatic agents, crystal nucleating agents, thickeners, A heat stabilizer, a coloring pigment, an anti-coloring agent, an ultraviolet absorber and the like can be added. Further, it is preferable to add fine particles as a lubricant for improving the slipperiness of the laminate to at least the outermost layer of the laminate. Any fine particles can be selected. For example, the inorganic fine particles may include silica, alumina, titanium dioxide, calcium carbonate, kaolin, barium sulfate, and the like, and the organic fine particles include acrylic resin particles, melamine resin particles, silicone resin particles, crosslinked polystyrene. Examples thereof include particles. The average particle size of the fine particles can be appropriately selected as needed within the range of 0.05 to 3.0 μm when measured with a Coulter counter.

As a method of blending the particles into the heat-sealing layer and the base material layer constituting the laminate of the present invention, for example, the particles can be added at any stage of producing the polyester resin (resin). It is preferable that the polycondensation reaction is carried out by adding as a slurry dispersed in ethylene glycol or the like in the step or after the completion of the transesterification reaction and before the start of the polycondensation reaction. Further, using a kneading extruder with a vent, a method of blending a slurry of particles dispersed in ethylene glycol, water, or another solvent and a polyester resin raw material, or kneading and extruding dried particles and a polyester resin raw material. The method of blending using a machine is also included.

3.3. Adhesive Layer As the adhesive layer in the laminate of the present invention, an adhesive for dry lamination or a resin layer formed by extrusion lamination can be used. The adhesive may be either one-pack type (dry type) or two-pack type (curing reaction type). In the case of dry lamination, commercially available polyurethane or polyester adhesives for dry lamination can be used. As typical examples, DIC Dry (registered trademark) LX-703VL manufactured by DIC, KR-90 manufactured by DIC, Takenate (registered trademark) A-4 manufactured by Mitsui Chemicals, and Takelac (registered trademark) A-905 manufactured by Mitsui Chemicals, Inc. And so on. In the case of extrusion lamination, a polyolefin resin such as polyethylene is melted and adhered between layers or between a layer and another layer, but an anchor coat layer is laminated in order to enhance the adhesiveness of the surface of the layer or the like. Is also preferable.
The adhesive layer is formed by applying an adhesive to the film of either the heat seal layer or the base material layer, and then drying or reacting the adhesive to cure the adhesive. In the laminate of the present invention, the thickness of the adhesive layer after drying the adhesive is preferably 1 μm or more and 6 μm or less, and more preferably 2 μm or more and 5 μm or less.

3.4. Resin layer other than base material layer, adhesive layer and sealant layer The laminate of the present invention may be provided with a resin layer other than the above-mentioned base material layer, adhesive layer and sealant layer. Providing this resin layer is preferable because it further improves the heat resistance and mechanical strength of the laminate. Further, it is preferable that the resin layer is laminated by coextrusion when forming the heat seal layer, and is formed in the same step as the heat seal layer. It is possible to avoid problems such as the heat seal layer being unintentionally stretched by the tension applied during the film forming process, and being melted and dropped during heat setting. The raw material species constituting the resin layer is a polyester composed of ethylene terephthalate described in the above “3.1. Heat seal layer”, or a polyester containing ethylene terephthalate as a main constituent and having a higher content of ethylene terephthalate than the heat seal layer. Is preferred.

3.5. Gas Barrier Layer As the raw material species of the gas barrier layer that can be used in the laminate of the present invention, conventionally known materials can be used and can be appropriately selected according to the purpose in order to satisfy desired gas barrier properties and the like. .. An inorganic thin film layer is preferable as the gas barrier layer. Examples of the raw material species of the inorganic thin film layer include metals such as silicon, aluminum, tin, zinc, iron, and manganese, and inorganic substances or inorganic compounds containing at least one of these metals. And oxides, nitrides, carbides, fluorides, etc. These inorganic substances or inorganic compounds may be used alone or in combination. In particular, it is preferable to use silicon oxide or aluminum oxide alone (one body) or in combination (binary body) because the transparency of the laminate can be improved. When the component of the inorganic compound is a binary body of silicon oxide and aluminum oxide, the content of aluminum oxide is preferably 20% by mass or more and 80% by mass or less, and more preferably 25% by mass or more and 70% by mass or less. .. When the content of aluminum oxide is 20% by mass or less, the density of the inorganic thin film layer may be lowered and the gas barrier property may be lowered, which is not preferable. Further, if the content of aluminum oxide is 80% by mass or more, the flexibility of the inorganic thin film layer is lowered, cracks are easily generated, and as a result, the gas barrier property may be lowered, which is not preferable.
It is preferable that the oxygen/metal element ratio of the metal oxide used in the inorganic thin film layer is 1.3 or more and less than 1.8, because there is little variation in the gas barrier property and an excellent gas barrier property is always obtained. The oxygen/metal element ratio can be determined by measuring the amounts of oxygen and metal elements by X-ray photoelectron spectroscopy (XPS) and calculating the oxygen/metal element ratio.

3.6. Anchor Coat Layer In the laminate of the present invention, an anchor coat may be applied to the base material layer or the heat seal layer in advance before forming the gas barrier layer. By applying the 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.
The type of resin, cross-linking agent, compound, etc. constituting the anchor coat layer is not particularly limited, and includes oxazoline group-containing resin, acrylic resin, urethane resin, or a mixture containing two or more of these resins, polyvinyl acetal and polyester polyol. And a combination of an isocyanate compound and a silane coupling agent, a mixture of a silicon compound such as tetraethoxysilane or tetramethoxysilane or a hydrolyzate thereof and a water-soluble polymer having a hydroxyl group, a silicone resin, a polysilazane resin And a silane compound resin can be used as a mixture.
The method for forming the anchor coat layer is not particularly limited, and a known method can be arbitrarily adopted. In-line coating method in which a coating step is provided during the film-forming step of the resin layer such as the base material layer or heat seal layer, or an off-line coating method in which the film as the base material layer or heat seal layer is wound up as a roll and then coated But it doesn't matter. The off-line coating method is preferably the in-line coating method because the productivity is inferior as much as the resin film is wound up and then unwound and coated by another facility. In the in-line coating method, the following 4.1. 4.1.2 described in “Film forming conditions of polyester resin layer”. "First (longitudinal) stretching" or 4.1.3. After the "intermediate heat treatment", coating is performed, and 4.1.4. "Second (transverse) stretching" to 4.1.5. The solvent is dried until the "final heat treatment" (in the tenter). Therefore, the maximum temperature for drying the coating liquid depends on the final heat treatment temperature, but normally 65°C or higher and 250°C or lower is sufficient. The coating method is not particularly limited, and includes gravure coating method, reverse coating method, dipping method, low coating method, air knife coating method, comma coating method, screen printing method, spray coating method, gravure offset method, die coating method, bar coating method. Known methods such as the above can be adopted.

3.7. Overcoat Layer After forming the above gas barrier layer on the laminate of the present invention, an overcoat layer may be provided thereon. By applying the overcoat, the scratch resistance and the gas barrier property of the laminate are improved.
The type of the overcoat layer is not particularly limited, but a composition comprising a urethane resin and a silane coupling agent, a compound comprising an organic silicon and a hydrolyzate thereof, a water-soluble polymer having a hydroxyl group or a carboxyl group, etc. Known materials can be used and can be appropriately selected according to the purpose in order to satisfy desired gas barrier properties and the like. Among these, a composition comprising a urethane resin and a silane coupling agent is preferable because it can improve gas barrier properties while maintaining flexibility of the laminate.
Further, the overcoat layer is added with one or more kinds of various additives for the purpose of imparting antistatic property, ultraviolet absorbing property, coloring, thermal stability, slip property, etc. within a range not impairing the object of the present invention. Alternatively, the type and amount of various additives can be appropriately selected according to the desired purpose.

4. Manufacturing conditions of laminated body 4.1. Film forming method of heat seal layer 4.1.1. Melt Extrusion The heat-sealing layer constituting the laminate of the present invention (hereinafter, the one described as "film" in the range of 4.1 indicates the heat-sealing layer) is the above-mentioned 3. 3.1. in “Layered Constituent Materials”. It can be obtained by melt-extruding the polyester raw material described in the "heat-sealing layer" with an extruder to form an unstretched laminated film, and stretching it by a predetermined method shown below. When the film includes layers other than the heat-sealing layer, the timing of laminating each layer may be before or after stretching. The heat seal layer is described in 4.1.4. Since the film is heated at a temperature equal to or higher than the melting point in the "final heat treatment", the film may melt and fall in the heating furnace if it is a single layer. Therefore, it is preferable to stack a heat resistant layer separately from the heat seal layer. When laminating before stretching, it is preferable to adopt a method of melting and extruding the resins as the raw materials of the respective layers by separate extruders and joining them by using a feed block or the like in the middle of the resin flow path. When laminating after stretching, it is preferable to employ a laminate in which films formed separately are laminated with an adhesive, or an extrusion laminate in which a melted polyester resin is poured onto the surface layer of the laminated film to laminate the films. Among these, the method of laminating each layer before stretching is preferable.
As described above, the polyester resin can be obtained by polycondensing by selecting the type and amount of the dicarboxylic acid component and the diol component so that an appropriate amount of a monomer other than ethylene terephthalate can be contained. Further, two or more kinds of chip-shaped polyester may be mixed and used as a raw material for the polyester resin layer.

When melt-extruding the raw material resin, it is preferable to dry the polyester raw material using a dryer such as a hopper dryer or paddle dryer, or a vacuum dryer. After drying the polyester raw material in this way, it is melted at a temperature of 200 to 300° C. using an extruder and extruded as a film. For extrusion, any existing method such as a T-die method or a tubular method can be adopted.

Then, the unstretched film can be obtained by rapidly cooling the film melted by extrusion. As a method of quenching the molten resin, a method of obtaining a substantially unoriented resin sheet by casting the molten resin from a die onto a rotating drum and quenching and solidifying can be suitably adopted.
The film may be formed by any of non-stretching, uniaxial stretching (stretching in at least one of the longitudinal (longitudinal) direction and the transverse (width) direction), and biaxial stretching. From the viewpoint of mechanical strength such as impact strength and puncture strength of the laminate of the present invention and productivity, uniaxial stretching is preferable, and biaxial stretching is more preferable. In the following, the longitudinal stretching is carried out by first performing longitudinal stretching and then transverse stretching-
The sequential biaxial stretching method by transverse stretching will be described. However, transverse stretching-longitudinal stretching in which the order is reversed may change the main orientation direction. Also, a simultaneous biaxial stretching method may be used.

4.1.2. Longitudinal stretching In the longitudinal direction (longitudinal direction), the unstretched film may be introduced into a longitudinal stretching machine in which a plurality of roll groups are continuously arranged. In the longitudinal stretching, it is preferable to preheat with a preheating roll until the film temperature reaches Tg to Tg+40°C. When the film temperature is lower than Tg, it becomes difficult to stretch the film when it is stretched in the machine direction, and breakage easily occurs, which is not preferable. On the other hand, if the temperature is higher than Tg+40° C., the film is likely to stick to the roll, and the film is easily wrapped around the roll or the roll is easily soiled due to continuous production, which is not preferable.
When the film temperature reaches 65°C to 90°C, longitudinal stretching is performed. The longitudinal stretching ratio is preferably 1 time or more and 5 times or less. Since 1 times means that the film is not longitudinally stretched, the longitudinal stretching ratio is 1 times to obtain a lateral uniaxially stretched film, and 1.1 times or more to obtain a biaxially stretched film. The upper limit of the longitudinal stretching ratio may be any number, but if the longitudinal stretching ratio is too high, not only lateral stretching becomes difficult and breakage easily occurs, but also the molecular orientation angle (bowing) becomes large. It is preferably not more than twice.

Further, by relaxing the film in the longitudinal direction after the longitudinal stretching (relaxing in the longitudinal direction), the shrinkage rate in the longitudinal direction of the film caused by the longitudinal stretching can be reduced. Further, by relaxing in the longitudinal direction, the bowing phenomenon (distortion) that occurs in the tenter can be reduced. This is because, in the subsequent lateral stretching and final heat treatment, the film is heated while being held at both ends in the film width direction, 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 (a relaxation rate of 0% indicates that relaxation is not performed). The upper limit of the relaxation rate in the longitudinal direction is determined by the raw material used and the longitudinal stretching conditions, and therefore the relaxation cannot be performed beyond this. The upper limit of the relaxation rate in the longitudinal direction of the polyester sealant of the present invention is 70%. The relaxation in the longitudinal direction can be carried out by heating the film after longitudinal stretching at a temperature of 65° C. to 100° C. or less and adjusting the speed difference of the rolls. As the heating means, any of rolls, near infrared rays, far infrared rays, hot air heaters and the like can be used. Further, the relaxation in the longitudinal direction can be performed not only immediately after the longitudinal stretching but also in the lateral stretching (including the preheating zone) or the final heat treatment by narrowing the clip interval in the longitudinal direction (in this case, both ends in the film width direction). Also, since it is relaxed in the longitudinal direction, bowing distortion is reduced), and it can be performed at any timing.
After relaxing in the longitudinal direction (longitudinal stretching when not relaxing), the film is preferably cooled once, and preferably cooled by a cooling roll having a surface temperature of 20 to 40°C.

4.1.3. Lateral Stretching After longitudinal stretching, the film is laterally stretched in a tenter at a stretch ratio of 3 to 5 times at Tg to Tg + 50°C, with both edges of the film in the width direction (direction orthogonal to the longitudinal direction) being held by clips. It is preferable to carry out. Prior to the stretching in the transverse direction, preheating is preferably performed, and preheating is preferably performed until the film surface temperature reaches Tg-10°C to Tg+40°C.
After transverse stretching, the film is preferably passed through an intermediate zone where no positive heating operation is carried out. Since the temperature is higher in the final heat treatment zone subsequent to the transverse stretching zone of the tenter, heat (hot air itself or radiant heat) in the final heat treatment zone flows into the transverse stretching process unless the intermediate zone is provided. In this case, since the temperature of the transverse stretching zone is not stable, not only the thickness accuracy of the film is deteriorated, but also physical properties such as heat seal strength and shrinkage ratio are varied. Therefore, it is preferable that the film after the transverse stretching is passed through the intermediate zone for a predetermined time and then subjected to the final heat treatment. In this intermediate zone, when a strip-shaped piece of paper hangs down while the film is not passing through, it is possible for the piece of paper to hang down almost completely in the vertical direction. It is important to block the hot air from the heat treatment zone. A transit time of 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 becomes insufficient and the heat blocking effect becomes insufficient. On the other hand, it is preferable that the intermediate zone is long, but if it is too long, the equipment becomes large, so about 5 seconds is sufficient.

4.1.4. Final heat treatment After passing through the intermediate zone, it is preferable to perform heat treatment at 160°C or higher and 250°C or lower in the final heat treatment zone. If the heat treatment temperature is lower than 160° C., the shrinkage rate of hot water at 98° C. of the laminate will be higher than 5%, which is not preferable. The higher the heat treatment temperature is, the lower the shrinkage rate of the film is, but if it is higher than 250°C, the haze of the film is higher than 15%, the molecular orientation angle of the film is higher than 30°C, the film is melted during the final heat treatment step. It is not preferable because the problem of falling into the tenter easily occurs.
At the time of the final heat treatment, the shrinkage ratio in the width direction can be reduced by reducing the distance between clips in the width direction 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 in the range of 0% or more and 10% or less (a relaxation rate of 0% indicates that relaxation is not performed). The higher the relaxation ratio in the width direction, the lower the shrinkage ratio in the width direction, but the upper limit of the relaxation ratio (shrinkage ratio in the width direction of the film immediately after transverse stretching) is the upper limit of the raw material used, the stretching conditions in the width direction, and the heat treatment temperature. It is not possible to carry out relaxation beyond this as it is decided by. In the heat seal layer used in the present invention, the relaxation rate in the width direction has an upper limit of 10%.

Furthermore, during the final heat treatment, the shrinkage ratio in the longitudinal direction can be reduced by shortening the distance between clips in the longitudinal direction of the tenter by an arbitrary ratio (relaxation in the longitudinal direction). Therefore, relaxation in the longitudinal direction during the final heat treatment is a preferable mode. Although the higher the relaxation rate in the longitudinal direction, the lower the contraction rate in the longitudinal direction, the upper limit of the relaxation rate (the contraction rate in the longitudinal direction of the film immediately after transverse stretching) is the upper limit of the raw material used and the stretching/relaxation conditions in the longitudinal direction. Since it depends on the heat treatment temperature, the relaxation cannot be performed beyond this. In the heat-sealing layer of the present invention, the relaxation rate in the longitudinal direction has an upper limit of 10%.

Also, the transit time of the final heat treatment zone is preferably 2 seconds or more and 20 seconds or less. When the passage time is 2 seconds or less, the surface temperature of the film passes through the heat treatment zone without reaching the set temperature, so that the heat treatment becomes meaningless. The longer the passage time is, the higher the effect of the heat treatment is. Therefore, the passage time is preferably 2 seconds or more, more preferably 5 seconds or more. However, if the passage time is lengthened, the equipment becomes huge, so 20 seconds or less is practically sufficient.

4.1.5. Cooling After passing the final heat treatment, it is necessary to cool the film in the cooling zone with cooling air of 10° C. or higher and 30° C. or lower until the actual temperature of the film becomes the glass transition temperature (Tg) or lower. At this time, it is preferable to lower the temperature of the cooling air or increase the wind speed to improve the cooling efficiency. The actual temperature is the film surface temperature measured by a non-contact radiation thermometer. If the film at the exit of the tenter is not sufficiently cooled and the actual temperature of the film exceeds Tg, thermal contraction will occur even after the film is released from the clip, so the characteristics and thickness of the film may change. is there. The layers other than the heat-sealing layer are the same as those in 4.1. 4.1.1. in "Method for forming heat seal layer". When laminating by the method described in "melt extrusion", it is necessary that the actual temperature of the film at the exit of the tenter is lower than the Tg of the lower layer. If the actual temperature of the film at the exit of the tenter exceeds the glass transition temperature when layers other than the heat seal layer are laminated, the film will heat shrink when both ends of the film held by the clips are released. Not only that, but also the layer having a large heat shrinkage is curled, which is not preferable.

The passage time through the cooling zone is preferably 2 seconds or more and 20 seconds or less. If the passage time is 2 seconds or less, the curl becomes large because the film passes through the cooling zone without reaching the glass transition temperature. The longer the passage time is, the higher the cooling effect is. Therefore, the passage time is preferably 2 seconds or more, more preferably 5 seconds or more. However, if the passage time is lengthened, the equipment becomes huge, so 20 seconds or less is practically sufficient.
After that, the film roll as a heat-sealing layer can be obtained by winding the film while cutting and removing both end portions of the film.

4.2. Film forming method of base material layer 4.2.1. Melt Extrusion The base material layer (hereinafter referred to as “film” in the range of 4.2. refers to the base material layer) constituting the laminate of the present invention is the same as in 3. above. 3.2. in "Materials for Laminate" It can be obtained by melt-extruding the raw material described in the "base material layer" with an extruder to form an unstretched laminated film, and stretching it by a predetermined method shown below. Here, polybutylene terephthalate or polyethylene terephthalate will be described. When the film includes a layer other than the base material layer, the timing of laminating each layer may be before or after stretching. When laminating before stretching, it is preferable to adopt a method of melting and extruding the resins as the raw materials of the respective layers by separate extruders and joining them by using a feed block or the like in the middle of the resin flow path. When laminating after stretching, it is preferable to employ a laminate in which films formed separately are laminated with an adhesive, or an extrusion laminate in which a melted polyester resin is poured onto the surface layer of the laminated film to laminate the films. Among these, the method of laminating each layer before stretching is preferable. Further, for the purpose of suppressing excessive crystallization when the film is stretched, the same resin may be laminated in four or more layers by a static mixer or a multilayer feed block.

The polyester resin can be obtained by polycondensing by selecting the types and amounts of the dicarboxylic acid component and the diol component. Further, two or more kinds of chip-shaped polyester may be mixed and used as a raw material for the polyester resin layer.
When the raw material resin is melt-extruded, it is preferable to dry the polyester raw material using a dryer such as a hopper dryer or a paddle dryer, or a vacuum dryer. After drying the polyester raw material in this way, it is melted at a temperature of 200 to 300° C. using an extruder and extruded as a film. For extrusion, any existing method such as a T-die method or a tubular method can be adopted.

Then, the unstretched film can be obtained by rapidly cooling the film melted by extrusion. As a method of quenching the molten resin, a method of obtaining a substantially unoriented resin sheet by casting the molten resin from a die onto a rotating drum and quenching and solidifying can be suitably adopted.
The film may be formed by any method of non-stretching, uniaxial stretching and biaxial stretching. From the viewpoint of mechanical strength such as impact strength and puncture strength of the laminate of the present invention and productivity, uniaxial stretching is preferable, and biaxial stretching is more preferable. In the following, a sequential biaxial stretching method in which longitudinal stretching is performed first and then transverse stretching is performed-longitudinal stretching-horizontal stretching is performed. However, even in transverse stretching-longitudinal stretching in which the order is reversed, the main orientation direction is It doesn't matter because it only changes. Also, a simultaneous biaxial stretching method may be used.

4.2.2. Longitudinal Stretching In the longitudinal stretching, the unstretched film may be introduced into a longitudinal stretching machine in which a plurality of roll groups are continuously arranged. In the longitudinal stretching, it is preferable to preheat with a preheating roll until the film temperature reaches Tg to Tg+40°C. When the film temperature is lower than Tg, it becomes difficult to stretch the film when it is stretched in the machine direction, and breakage easily occurs, which is not preferable. On the other hand, if the temperature is higher than Tg+40° C., the film is likely to stick to the roll, and the film is easily wrapped around the roll or the roll is easily soiled due to continuous production, which is not preferable.

Longitudinal stretching is performed when the film temperature reaches Tg to Tg + 40°C. The longitudinal stretching ratio is preferably 1 time or more and 5 times or less. Since 1 times means that the film is not longitudinally stretched, the longitudinal stretching ratio is 1 times to obtain a lateral uniaxially stretched film, and 1.1 times or more to obtain a biaxially stretched film. The upper limit of the longitudinal stretching ratio may be any number, but if the longitudinal stretching ratio is too high, lateral stretching becomes difficult and breakage is likely to occur, so that it is preferably 5 times or less.

4.2.3. Lateral Stretching After longitudinal stretching, the film is laterally stretched in a tenter at a stretch ratio of 3 to 5 times at Tg to Tg + 50°C, with both edges of the film in the width direction (direction orthogonal to the longitudinal direction) being held by clips. It is preferable to carry out. Prior to the stretching in the transverse direction, preheating is preferably performed, and preheating is preferably performed until the film surface temperature reaches Tg-10°C to Tg+40°C.
After transverse stretching, the film is preferably passed through an intermediate zone where no positive heating operation is carried out. Since the temperature is higher in the final heat treatment zone subsequent to the transverse stretching zone of the tenter, heat (hot air itself or radiant heat) in the final heat treatment zone flows into the transverse stretching process unless the intermediate zone is provided. In this case, since the temperature of the transverse stretching zone is not stable, the film thickness accuracy is deteriorated. Therefore, it is preferable that the film after the transverse stretching is passed through the intermediate zone for a predetermined time and then subjected to the final heat treatment. In this intermediate zone, when a strip-shaped piece of paper hangs down while the film is not passing through, it is possible for the piece of paper to hang down almost completely in the vertical direction. It is important to block the hot air from the heat treatment zone. A transit time of 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 becomes insufficient and the heat blocking effect becomes insufficient. On the other hand, it is preferable that the intermediate zone is long, but if it is too long, the equipment becomes large, so about 5 seconds is sufficient.

4.2.4. Final heat treatment After passing through the intermediate zone, it is preferable to perform heat treatment at 180°C or higher and 280°C or lower in the final heat treatment zone. If the heat treatment temperature is lower than 180° C., the shrinkage rate of hot water at 98° C. of the laminate will be higher than 5%, which is not preferable. The higher the heat treatment temperature, the lower the shrinkage factor of the film, but if the heat treatment temperature is higher than 280° C., the problem that the film melts and drops into the tenter during the final heat treatment step is not preferable, which is not preferable.

▽During the final heat treatment, the shrinkage ratio in the width direction can be reduced by reducing the distance between clips in the width direction of the tenter by an arbitrary ratio. Therefore, in the final heat treatment, it is preferable to relax in the width direction in the range of 0% or more and 5% or less. The higher the relaxation rate in the width direction, the lower the shrinkage rate in the width direction.However, the upper limit of the relaxation rate is determined by the raw material used, the stretching conditions in the width direction, and the heat treatment temperature. Can not. In the base material layer used in the present invention, the relaxation rate in the width direction has an upper limit of 5%.

Furthermore, during the final heat treatment, the shrinkage ratio in the longitudinal direction can be reduced by reducing the distance between clips in the longitudinal direction of the tenter by an arbitrary ratio. Although the higher the relaxation rate in the longitudinal direction, the lower the contraction rate in the longitudinal direction, the upper limit of the relaxation rate (the contraction rate in the longitudinal direction of the film immediately after transverse stretching) is the upper limit of the raw material used and the stretching/relaxation conditions in the longitudinal direction. Since it depends on the heat treatment temperature, the relaxation cannot be performed beyond this. In the heat-sealing layer of the present invention, the relaxation rate in the longitudinal direction has an upper limit of 5%.

4.2.5. Cooling After passing the final heat treatment, it is necessary to cool the film in the cooling zone with cooling air of 10° C. or higher and 30° C. or lower until the actual temperature of the film becomes the glass transition temperature (Tg) or lower. At this time, it is preferable to lower the temperature of the cooling air or increase the wind speed to improve the cooling efficiency. The actual temperature is the film surface temperature measured by a non-contact radiation thermometer. If the film at the exit of the tenter is not sufficiently cooled and the actual temperature of the film exceeds Tg, thermal contraction will occur even after the film is released from the clip, so the characteristics and thickness of the film may change. is there. The layers other than the heat-sealing layer are the same as those in 4.1. 4.2.1. in "Method for forming heat seal layer". When laminating by the method described in "melt extrusion", it is necessary that the actual temperature of the film at the exit of the tenter is lower than the Tg of the lower layer. If the actual temperature of the film at the exit of the tenter exceeds the glass transition temperature when layers other than the heat seal layer are laminated, the film will heat shrink when both ends of the film held by the clips are released. Not only that, but also the layer having a large heat shrinkage is curled, which is not preferable.

The passage time through the cooling zone is preferably 2 seconds or more and 20 seconds or less. If the passage time is 2 seconds or less, the curl becomes large because the film passes through the cooling zone without reaching the glass transition temperature. The longer the passage time is, the higher the cooling effect is. Therefore, the passage time is preferably 2 seconds or more, more preferably 5 seconds or more. However, if the passage time is lengthened, the equipment becomes huge, so 20 seconds or less is practically sufficient.
After that, the film roll as a base material layer can be obtained by winding the film while cutting and removing both end portions of the film.

4.3. Method for Laminating Gas Barrier Layer The method for laminating the gas barrier layer in the laminate of the present invention is not particularly limited, and a known manufacturing method can be adopted as long as the object of the present invention is not impaired. For example, there is a method of depositing a metal material by a vacuum vapor deposition method, a sputtering method, a PVD method (physical vapor deposition method) such as ion plating, or a CVD method (chemical vapor deposition method). Further, a method of laminating a metal foil such as aluminum foil on the film may be adopted. Among these, the vacuum vapor deposition method is particularly preferable from the viewpoint of production speed and stability. As a heating method in the vacuum vapor deposition method, resistance heating, high frequency induction heating, electron beam heating or the like can be used. Further, as the 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. Further, the conditions may be changed as long as the object of the present invention is not impaired, for example, by applying a bias or the like to the substrate, raising or cooling the substrate temperature.

4.4. Method for forming overcoat layer The method for laminating the overcoat in the laminate of the present invention is not particularly limited, and includes a gravure coating method, a reverse coating method, a dipping method, a low coating method, an air knife coating method, a comma coating method, and a screen printing method. Conventionally known coating methods such as a spray coating method, a gravure offset method, a die coating method and a bar coating method can be used, and can be appropriately selected according to a desired purpose.

As the drying method, hot air drying, hot roll drying, high frequency irradiation, infrared irradiation, UV irradiation, or the like can be used alone or in combination of two or more. In the drying method, the heating temperature is preferably in the range of 60°C or higher and 200°C or lower, and more preferably in the range of 80°C or higher and 180°C or lower. When the drying temperature is 60° C. or higher, a desired barrier property is exhibited, which is good. When the drying temperature is 180° C. or lower, deformation of the base material and cracks in the vapor deposition film do not occur for a short vapor deposition time, which is preferable.

4.5. Method for Adhering Laminate In the laminate of the present invention, a heat-sealing layer and a base material layer (including a gas barrier layer, an anchor coat layer, and an overcoat layer laminated on any layer, if necessary) are used as an adhesive layer. In order to laminate the films via the, the adhesive forming the adhesive layer is first applied to one of the films. Then, the other film is attached to the surface coated with the adhesive, and the adhesive is dried to volatilize the solvent. Drying conditions differ depending on the adhesive, but the adhesive cures when left in a 40° C. environment for one day or more, for example.

5. Configuration of Package, Bag Making Method The laminate having the above properties can be suitably used as a package. The laminate of the present invention can be used alone as a bag, but other materials may be laminated. As the other layer constituting the laminate, for example, a non-stretched film containing polyethylene terephthalate as a constituent component, a non-stretched film containing another amorphous polyester as a constituent component, a uniaxially stretched or biaxially stretched film, a constituent component of nylon. Examples of the non-stretched film include a non-stretched film, a uniaxially stretched film or a biaxially stretched film, a non-stretched film containing polypropylene as a constituent component, a uniaxially stretched film, or a biaxially stretched film. The method of using the laminate for the package is not particularly limited, and a conventionally known manufacturing method such as a coating forming method, a laminating method, and a heat sealing method can be adopted.
The package may be at least partially formed of the laminate according to the present invention, but a configuration in which the above-described laminate is present in the entire package is preferable because the gas barrier property of the package is improved. .. Further, the package may be in any layer of the laminate of the present invention, but considering the non-adhesiveness to the contents and the sealing strength when making a bag, the heat-sealing layer of the laminate of the present invention Is preferably the innermost layer of the bag.

The method for bag-making the package having the laminate of the present invention is not particularly limited, and conventionally known production methods such as heat sealing using a heat bar (heat jaw), adhesion using hot melt, and center sealing with a solvent can be used. Can be adopted.
The package having the laminate of the present invention can be suitably used as a packaging material for various products such as foods, pharmaceuticals, and industrial products.

Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the modes of the Examples, and may be appropriately changed without departing from the gist of the present invention. Is possible.
The evaluation method of the laminate is as follows. In addition, when the longitudinal direction and the width direction cannot be specified immediately because the area of the laminated body is small, the longitudinal direction and the width direction may be temporarily determined and the measurement may be performed. The difference of 90 degrees does not cause any particular problem.

<Evaluation method of laminated body>
[Heat seal strength]
The heat seal strength was measured according to JIS Z1707. A specific procedure is shown. 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 out 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 indicated by the strength per 15 mm (N/15 mm).

[Impact strength]
According to JIS K7160-1996, an impact tester manufactured by Toyo Seiki Seisaku-sho, Ltd. was used to measure the energy for impact punching of the laminate in an atmosphere of 23°C.

[Puncture strength]
Puncture at 23°C in accordance with “2. Test method for strength, etc.” of “Standards for foods, additives, etc. 3: Appliances and containers and packaging” (Ministry of Health and Welfare Notification No. 20 of 1982) in the Food Sanitation Law. The strength was measured. A needle having a tip diameter of 0.7 mm was pierced from the heat-sealing layer (innermost layer side) of the laminate at a piercing speed of 50 mm/min, and the strength when the needle penetrated the film was measured. The puncture strength was calculated per unit thickness of the laminate (N/μm).

[Water vapor permeability]
The water vapor permeability was measured according to JIS K7126 B method. Using a water vapor permeability measuring device (PERMATRAN-W3/33MG MOCON), the humidity control gas permeates from the heat seal layer side to the inorganic thin film layer side of the laminate in an atmosphere of a temperature of 40° C. and a humidity of 90% RH. The water vapor permeability was measured in the following direction. Before the measurement, the sample was allowed to stand for 4 hours in a RH environment of 65% RH to control the humidity.

[Oxygen permeability]
The oxygen permeability was measured according to JIS K7126-2 method. Oxygen permeates from the heat seal layer side of the laminate to the inorganic thin film layer side in an atmosphere of a temperature of 23° C. and a humidity of 65% RH using an oxygen permeation measuring device (manufactured by OX-TRAN 2/20 MOCOM). The oxygen permeability was measured in the direction. Before the measurement, the sample was allowed to stand for 4 hours in a RH environment of 65% RH to control the humidity.

[Hot water heat shrinkage rate]
The sample was cut into a square of 10 cm×10 cm, dipped in hot water of 98±0.5° C. for 3 minutes in a no-load state to shrink, and then dipped in water of 25°±0.5° C. for 10 seconds, I took it 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 calculated according to the following equation 2. In addition, the measurement was performed twice and the average value was calculated.

Shrinkage rate={(length before shrinkage-length after shrinkage)/length before shrinkage}×100(%) Equation 2

The heat shrinkage rates in the vertical and horizontal directions were evaluated according to the following criteria. The criteria for judgment are as follows.

Judgment ○ Heat shrinkage rate 5% or less Judgment × Heat shrinkage rate 5% or more

[Drop bag evaluation]
Cut the laminate to a size of 15 cm square, stack the two so that the sealant is on the inside, and heat seal the three sides at a temperature of 140°C, pressure of 0.2 MPa, time of 0.2 seconds, width of 1.0 cm. By doing so, a three-sided sealed bag having an inner size of 13 cm was obtained.
Five Kim towels (registered trademark, made by Nippon Paper Crecia, size 380 mm x 330 mm) whose weight was adjusted to 300 g by absorbing water were rolled into the obtained three-sided seal bag, and the same heat-sealing conditions as above were applied. Then, the mouth of the fourth side was closed and a four-sided sealed bag was produced.

The obtained four-side sealed bag was dropped 5 times in succession from a position of 100 cm in height at a room temperature of 0° C. on a concrete plate, and as shown below, the number of times until the bag was broken was taken as a drop bag score. I asked. The drop bag score was calculated as the sum after 5 trials (maximum 4 points×5 times=maximum 20 points).

1st time bag breaking 0 points 2nd time bag breaking 1 point 3rd time bag breaking 2 points 4th time bag breaking 3 points 5th time bag breaking 4 points

A drop bag score of 10 points or more was passed (◯), and a score of 9 points or less was rejected (x).

[Adsorption]
The laminate was cut into a square of 10 cm×10 cm, two sheets were stacked with the heat-sealing surface inside, and a position 1 cm from the edge of the film was heat-sealed to form a bag. An aluminum cup containing 0.5 ml of the content was placed in the bag, and the position 1 cm from the end of the laminate was heat-sealed to close the bag. As the contents, D-limonene (manufactured by Tokyo Chemical Industry Co., Ltd.) and L-menthol (manufactured by Nacalai Tesque, Inc.) were used. After holding for 20 hours in a 30°C environment, cut a 5 cm × 5 cm square from the surface of the bag that contacts the mouth of the aluminum cup, and sonicate for 30 minutes while immersing the cut laminated body in 4 ml of extraction solvent. did. 99.8% ethanol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was used as the extraction solvent. The concentration of the contents in the extraction solution was quantified using a gas chromatograph "GC-14B" manufactured by Shimadzu Corporation. The gas chromatograph uses "GC-14A Glass ID 2.6φ x 1.1 m PET-HT 5% Uniport HP 80/100 (manufactured by GL Sciences)" for the column, FID for the detector, and N ₂ for the carrier gas. The carrier gas flow rate was 35 ml/min, and the injection rate was 1 μl. The adsorption amount was indicated by an adsorption amount (μg/cm ² ) per 1 cm ² of the heat-sealed surface, and the low adsorption property was determined as follows.

Judgment ○ 0 μg/cm ² or more, less than 2 μg/cm ² Judgment × 2 μg/cm ² or more

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

[Synthesis example 2]
Polyesters (B) to (G) in which the monomers were changed were obtained by the same procedure as in Synthesis Example 1. The composition of each polyester is shown in Table 1. 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. During the production of the polyester (G), SiO2 (Silysia 266 manufactured by Fuji Silysia Chemical Ltd.) was added as a lubricant at a ratio of 7,000 ppm with respect to the polyester. Each polyester was chipped appropriately. Table 1 shows the composition of the polyesters (B) to (G).

[Film 1]
Polyester A, polyester B, polyester E and polyester G were mixed at a mass ratio of 9:60:24:7 as raw materials for the heat seal layer (A layer), and polyester A and polyester as raw materials for the other layers (B layer). B, polyester E, and polyester G were mixed in a mass ratio of 56:31:6:7.

The mixed raw materials of the A layer and the B layer were put into separate twin-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 flow path of the molten resin is set so that one side is the A layer and the other side is the B layer (two-layer two-layer structure of A layer/B layer), and the thickness ratio of the A layer and the B layer is 50/ The discharge amount was adjusted to be 50.

The unstretched laminated film obtained by cooling and solidification is guided to a longitudinal stretching machine in which a plurality of roll groups are continuously arranged, preheated on a preheating roll until the film temperature reaches 80° C., and then stretched 4.2 times. did. The film immediately after longitudinal stretching was passed through a heating furnace set at 100° C. with a hot air heater, and a 30% relaxation treatment was performed in the longitudinal direction by utilizing the speed difference between the rolls at the inlet and outlet of the heating furnace. Then, the longitudinally stretched film was forcibly cooled by a cooling roll whose surface temperature was set to 25°C.

The relaxed film was introduced into 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 (transverse direction). The laterally stretched film was guided to the intermediate zone as it was, and allowed to pass for 1.0 second. In the intermediate zone of the tenter, when a strip-shaped piece of paper is hung while the film is not passing, the hot air from the final heat treatment zone and the transverse stretching zone are so that the piece of paper hangs almost completely in the vertical direction. Cut off the hot air from.

After that, the film that passed through the intermediate zone was guided to the final heat treatment zone and heat treated at 190°C for 5 seconds. At this time, the heat treatment was performed, and at the same time, the clip interval in the film width direction was narrowed to perform 3% relaxation treatment in the width direction. After passing through the final heat treatment zone, the film was cooled with cooling air of 30° C. for 5 seconds. At this time, the actual film temperature at the exit of the tenter was 45°C. Both edges were cut off and wound into a roll with a width of 500 mm to continuously produce a biaxially stretched film having a thickness of 30 μm over a predetermined length. The characteristics of the obtained film were evaluated by the above methods. Table 2 shows the production conditions.

[Film 2]
Polyester B, polyester C, and polyester G were mixed as a raw material of the A layer in a mass ratio of 40:43:7, and were mixed in the same ratio as the B layer of the film 1 as a raw material of the B layer.
The mixed raw materials of the layer A and the layer B were respectively put into separate twin-screw extruders, melted and laminated in the same manner as the film 1 above, discharged, and cooled and solidified to obtain an unstretched laminated film. ..
This unstretched laminated film was introduced into a simultaneous biaxial stretching machine and preheated for 5 seconds until the surface temperature reached 100° C., and then the longitudinal direction (longitudinal direction) was multiplied by 3.6 times the width direction (lateral direction). ) Was simultaneously biaxially stretched to 4.2 times. The film after the simultaneous biaxial stretching was guided to the intermediate zone as it was, and allowed to pass for 1.0 second. In the intermediate zone, when a strip-shaped paper piece is hung in a state where the film is not passed, so that the paper piece hangs almost completely in the vertical direction, hot air from the final heat treatment zone and from the lateral stretching zone The hot air was shut off.

After that, the film that passed through the intermediate zone was guided to the final heat treatment zone and heat-treated at 210°C for 10 seconds. At this time, the heat treatment was performed, and at the same time, the clip interval in the longitudinal direction of the film and the clip interval in the width direction were simultaneously narrowed to perform relaxation treatment of 18% in the longitudinal direction and 3% in the width direction. After passing through the final heat treatment zone, the film was cooled with cooling air of 30° C. for 5 seconds. At this time, the actual film temperature at the exit of the tenter was 45°C. Both edges were cut off and wound into a roll with a width of 500 mm to continuously produce a biaxially stretched film having a thickness of 30 μm over a predetermined length. The characteristics of the obtained film were evaluated by the above methods. Table 2 shows the production conditions.

[Film 3]
In the same manner as the film 1, the film 3 was also formed into a polyester film in which the raw material mixing ratio, the longitudinal stretching, the relaxation in the longitudinal direction, the lateral stretching, and the final heat treatment were changed. Table 2 shows the production conditions of each film.

[Film 4]
As raw materials for the layer A, polyester E and polyester G were mixed at a mass ratio of 95:5, charged into a twin screw extruder and melted at 260°C. This molten resin was discharged alone from a T die and cooled on a chill roll set to a surface temperature of 30° C. to obtain an unstretched monolayer film.
This unstretched single-layer film was subjected to a sequential biaxial stretching method similarly to the film 1 to form a polyester film in which the respective conditions of longitudinal stretching, transverse stretching and final heat treatment were changed. The film 4 was not relaxed in the longitudinal direction during the film forming process. Table 2 shows the production conditions.

[Film 5]
As the film 5, Pyrene film-CT (registered trademark) P1128-30 μm manufactured by Toyobo Co., Ltd. was used. It is shown in Table 2 together with the films 1 to 4.

[Film 6]
Polyester A and polyester G were mixed as a raw material for the base material layer (C layer) at a mass ratio of 95:5, and the mixture was put into a twin-screw extruder and melted at 275°C. This molten resin was discharged alone from a T die and cooled on a chill roll set to a surface temperature of 30° C. to obtain an unstretched monolayer film.
This unstretched single-layer film was subjected to a sequential biaxial stretching method similarly to the film 1 to form a polyester film in which the respective conditions of longitudinal stretching, transverse stretching and final heat treatment were changed. The film 6 was not relaxed in the longitudinal direction during the film forming process. Table 3 shows the manufacturing conditions.

[Film 7]
As raw materials for the layer C, polyester A, polyester E and polyester G were mixed at a mass ratio of 13:80:7, charged into a twin screw extruder and melted at 265°C. At this time, the melt line was connected to a 12-element static mixer, and the same resin was divided and laminated into 4096 layers. This molten resin was discharged from a T-die and cooled on a chill roll set to a surface temperature of 30° C. to obtain an unstretched film (a raw material resin species was the above mixing ratio single and the number of layers was 4096).
This unstretched film was subjected to a sequential biaxial stretching method in the same manner as the film 1 to form a polyester film in which the respective conditions of longitudinal stretching, transverse stretching and final heat treatment were changed. The film 7 was not relaxed in the longitudinal direction during the film forming process. Table 3 shows the manufacturing conditions.

[Film 8]
As the film 8, Haden film (registered trademark) N1100-15 μm manufactured by Toyobo Co., Ltd. was used. It is shown in Table 3 together with the films 1 to 7.

[Example 1]
On the film 6, a urethane-based two-component curable adhesive (“Takelac (registered trademark) A525S” and “Takenate (registered trademark) A50” manufactured by Mitsui Chemicals, Inc. are mixed at a weight ratio of 13.5:1). A laminate was obtained by laminating the film 1 with the B layer side of the film 1 by a dry laminating method and aging at 40° C. for 4 days.
The properties of the obtained laminate were evaluated by the above methods. Table 4 shows the layer structure of the laminate, the physical properties, and the evaluation results of the package.

[Example 2]
A film was changed in the same manner as in Example 1 to prepare a laminate. The properties of the obtained laminate were evaluated by the above methods. It shows in Table 4.

[Example 3]
On one side of the film 7, aluminum was used as a vapor deposition source, and an aluminum oxide (Al ₂ O ₃ ) thin film was deposited as a gas barrier layer by a vacuum vapor deposition method while introducing oxygen gas with a vacuum vapor deposition machine. The thickness of the gas barrier layer was 10 nm. The gas barrier layer side of the film 7 and the B layer side of the film 3 were attached in the same manner as in Example 1 to produce a laminate. The properties of the obtained laminate were evaluated by the above methods. It shows in Table 4.

[Comparative Example 1]
The base material layer was not adhered, and only the film 1 was used as the heat seal layer. The properties of the single film were evaluated by the above methods. It shows in Table 4.

[Comparative Examples 2 and 3]
In the same manner as in Example 1, the film was changed to prepare a laminate. The properties of the obtained laminate were evaluated by the above methods. It shows in Table 4. In Comparative Example 2, the heat-sealing strength at 140° C. was zero, so a package could not be produced. Therefore, drop bag evaluation and adsorption evaluation were not performed.

[Film evaluation results]
From Table 4, all of the laminates of Examples 1 to 3 are excellent in heat seal strength, impact strength, puncture strength, heat shrinkage rate, bag breaking resistance, and non-adhesiveness, and good evaluation results are obtained. Was obtained. In addition, since the laminated body of Example 3 was provided with the gas barrier layer, it showed good gas barrier properties.
On the other hand, the film having only the heat-sealing layer of Comparative Example 1 had low impact strength and puncture strength, resulting in poor bag-breaking resistance.
Since the laminate of Comparative Example 2 had a heat seal strength of 140° C. of zero, it was unsuitable as a laminate for producing a package.
The sealant of Comparative Example 3 was inferior in non-adsorptive property because the heat seal layer used was an olefin type sealant.

According to the present invention, it is possible to provide a laminate having less adsorption of components of the content, high heat-sealing strength in a low temperature range, and excellent bag-breaking resistance, and to provide a package having the above characteristics. be able to.

Claims

At least three layers of a base material layer/adhesive layer/sealant layer are laminated in this order, and the base material layer is a polyester having polyethylene terephthalate or polybutylene terephthalate as a main constituent, or a polyolefin having polypropylene as a main constituent. , Or made of polyamide whose main constituent is nylon,
The sealant layer is made of polyethylene whose main constituent is polyethylene terephthalate,
A laminate having a seal strength of 8 N/15 mm or more and 70 N/15 mm or less when the sealant layers are sealed at 140° C. and 0.2 MPa for 2 seconds.
The laminate according to claim 1, wherein the base material layer is made of polyester having polyethylene terephthalate or polybutylene terephthalate as a main constituent.
The laminated body according to claim 1 or 2, further comprising a gas barrier layer laminated thereon.
The laminate according to any one of claims 1 to 3, wherein the puncture strength is 0.4 N/μm or more and 0.6 N/μm or less.
As a monomer component of the polyester component constituting the sealant layer, a diol monomer component other than ethylene glycol and/or an acid component other than terephthalic acid is contained, and the diol component is neopentyl glycol, 1,4-cyclohexanedimethanol, The laminate according to any one of claims 1 to 4, which is one or more selected from the group consisting of 1,4-butanediol and diethylene glycol, and the acid component is isophthalic acid.
A package comprising at least one layer of the laminate according to any one of claims 1 to 5.