JP7182085B2 - laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminate, and more particularly to a laminate using as a raw material a recycled polyester resin recovered from a packaging material or the like so as to be reused.

Plastics, which are materials derived from fossil fuels, are mainly used in the manufacture of packaging materials for filling products such as pharmaceuticals, cosmetics, and foods, from the viewpoints of ease of molding and cost. Polyester-based resins, polyolefin-based resins, polyamide-based resins, and the like are used as plastic materials widely used as materials for packaging containers. Among them, polyester-based resins are widely used in various industrial applications such as films, sheets, and packaging containers because they are excellent in mechanical properties, chemical stability, heat resistance, transparency, etc., and are inexpensive.

Polyester is obtained by polycondensation of diol units and dicarboxylic acid units. For example, polyethylene terephthalate (hereinafter sometimes abbreviated as PET) is produced by using ethylene glycol and terephthalic acid as raw materials and subjecting them to an esterification reaction and then a polycondensation reaction. These raw materials are produced from petroleum, which is a fossil resource. For example, ethylene glycol is industrially produced from ethylene, and terephthalic acid is industrially produced from xylene.

In recent years, with respect to such fossil fuel-derived materials, there has been an increasing trend year by year to reduce the use of fossil fuels in various applications and to reduce CO ₂ emissions in consideration of the environment. As an attempt to reduce the use of fossil fuels, a method has been proposed in which polyester resin recovered from used packaging materials such as PET bottles can be reused and recycled as recycled polyester for molding packaging materials ( For example, see Patent Documents 1 and 2). In Patent Documents 1 and 2, CO ₂ emissions are reduced by using polyester, which is made from polyester derived from fossil fuels and which has been recovered and made reusable, as part of the packaging material. It is proposed that

JP 2011-256328 A JP 2012-41463 A

However, packaging materials using recycled PET, which is mechanically recycled by pulverizing, washing, and reusing polyester resin products such as collected PET bottles, are contaminated due to foreign substances adhering to the recycled PET. There is an impression that there is a possibility that nations are occurring. For this reason, packaging materials manufactured using a laminate made of recycled PET, particularly packaging materials for filling products such as foods, are in a situation where it is difficult to gain trust from consumers.

An object of the present invention is to provide a laminate that can effectively solve such problems.

The present invention is a laminate comprising at least a substrate layer, a barrier layer, and a sealant layer in this order, wherein the substrate layer comprises a first layer, a second layer, and a third layer in this order, The first layer and the third layer are layers composed only of virgin polyethylene terephthalate, and the second layer is a layer composed only of recycled polyethylene terephthalate or a mixed layer of recycled polyethylene terephthalate and virgin polyethylene terephthalate. wherein the recycled polyethylene terephthalate includes polyethylene terephthalate having ethylene glycol as a diol unit and terephthalic acid and isophthalic acid as dicarboxylic acid units; the barrier layer includes a deposited film; and the base layer includes a recycled containing polyethylene terephthalate at a ratio of 50% by weight or more and 95% by weight or less, the thickness of the base layer being 5 μm or more and 25 μm or less,
The substrate layer is a laminate that is a biaxially stretched film.

In the laminate according to the present invention, the barrier layer may contain a metal-deposited film.

In the laminate according to the present invention, the barrier layer may contain a transparent deposition film.

The present invention is a laminate comprising at least a substrate layer, a barrier layer, and a sealant layer in this order, wherein the substrate layer comprises virgin polyethylene terephthalate, ethylene glycol as a diol unit, terephthalic acid and isophthalate. and a recycled polyethylene terephthalate containing polyethylene terephthalate having an acid as a dicarboxylic acid unit, and the base layer is a biomass polyester having a biomass-derived ethylene glycol as a diol unit and a fossil fuel-derived dicarboxylic acid as a dicarboxylic acid unit. The barrier layer does not contain a resin, the barrier layer contains a saponified ethylene-vinyl acetate copolymer, the thickness of the base layer is 5 μm or more and 25 μm or less, and the base layer is a biaxially stretched film. There is a laminate.

In the laminate according to the present invention, the isophthalic acid content may be 0.5 mol % or more and 5.0 mol % or less with respect to all dicarboxylic acid units constituting the polyethylene terephthalate.

In the laminate according to the present invention, the intrinsic viscosity of the polyethylene terephthalate may be 0.58 dl/g or more and 0.80 dl/g or less.

The invention is a packaging bag comprising a laminate according to the invention.

Advantageous Effects of Invention According to the present invention, it is possible to provide a laminate that is superior in CO ₂ reduction effect to a laminate made of polyethylene terephthalate that is not recycled, and that is excellent in sanitation.

1 is a schematic cross-sectional view showing an example of a laminate according to the present invention; FIG. 1 is a schematic cross-sectional view showing an example of a laminate according to the present invention; FIG. 1 is a schematic cross-sectional view showing an example of a laminate according to the present invention; FIG. 1 is a schematic cross-sectional view showing an example of a laminate according to the present invention; FIG. 1 is a schematic cross-sectional view showing an example of a substrate layer of a laminate according to the present invention; FIG.

<Laminate>
A laminate according to the present invention comprises at least a substrate layer, a barrier layer and a sealant layer in this order. The laminate may further comprise adhesive layers, printing layers, other layers and the like. When the laminate comprises two or more adhesive layers and other layers, each layer may have the same composition or may have different compositions.

A laminate according to the present invention will be described with reference to the drawings. Examples of schematic cross-sectional views of laminates according to the present invention are shown in FIGS. In the laminate 10 shown in FIG. 1, the barrier layer 12 contains at least the metal foil 121 . In the laminate 20 shown in FIGS. 2 and 3, the barrier layer 22 includes at least the vapor deposition film 220. As shown in FIG. In the laminate 30 shown in FIG. 4, the barrier layer 32 contains at least the saponified ethylene-vinyl acetate copolymer 321 .

The laminate 10 shown in FIG. 1 includes a substrate layer 11, an adhesive layer 14, a barrier layer 12, an adhesive layer 15, and a sealant layer 13 in this order. In the packaging bag including the laminate 10, the sealant layer 13 is located on the innermost surface.

The laminate 20 shown in FIG. 2 includes a substrate layer 21, an adhesive layer 24, a film substrate layer 221 of the vapor deposition film 220 that constitutes the barrier layer 22, and a vapor deposition layer of the vapor deposition film 220 that constitutes the barrier layer 22. 222, a gas barrier coating film 223 of the vapor deposition film 220 constituting the barrier layer 22, the adhesive layer 25, and the sealant layer 23 in this order. The sealant layer 23 is positioned on the innermost surface of the packaging bag including the laminate 20 .

The laminate 20 shown in FIG. 3 includes the base material layer 21, the adhesive layer 24, the gas barrier coating film 223 of the vapor deposition film 220 that constitutes the barrier layer 22, and the vapor deposition layer of the vapor deposition film 220 that constitutes the barrier layer 22. 222, the film base layer 221 of the deposited film 220 that constitutes the barrier layer 22, the adhesive layer 25, and the sealant layer 23 in this order. The sealant layer 23 is positioned on the innermost surface of the packaging bag including the laminate 20 .

A laminate 30 shown in FIG. Prepare in this order. The sealant layer 33 is positioned on the innermost surface of the packaging bag including the laminate 30 .

Each layer constituting the laminate will be described below.

[Base material layer]
The base material layer contains polyethylene terephthalate recycled by mechanical recycling (hereinafter polyethylene terephthalate is also referred to as PET). Specifically, the base material layer contains PET obtained by mechanically recycling PET bottles, and this PET contains ethylene glycol as the diol unit and terephthalic acid and isophthalic acid as the dicarboxylic acid unit. Here, mechanical recycling generally refers to the process of pulverizing collected PET bottles and other polyethylene terephthalate resin products, washing with alkali to remove dirt and foreign matter from the surface of the PET resin products, and then drying for a certain period of time under high temperature and reduced pressure. In this method, the contaminants remaining inside the PET resin are diffused and decontaminated, the dirt on the resin product made of the PET resin is removed, and the resin product is returned to the PET resin. Hereinafter, in this specification, polyethylene terephthalate obtained by recycling PET bottles is referred to as "recycled polyethylene terephthalate (hereinafter also referred to as recycled PET)", and polyethylene terephthalate that is not recycled is referred to as "virgin polyethylene terephthalate (hereinafter also referred to as virgin PET). )”.

Among the PET contained in the base material layer, the content of isophthalic acid is preferably 0.5 mol% or more and 5 mol% or less, and 1.0 mol%, based on the total dicarboxylic acid units constituting the PET. It is more preferable that the content is at least 2.5 mol % or less. When the content of isophthalic acid is less than 0.5 mol %, the flexibility may not be improved. PET may be biomass PET in addition to PET derived from ordinary fossil fuels. “Biomass PET” contains biomass-derived ethylene glycol as a diol unit and a fossil fuel-derived dicarboxylic acid as a dicarboxylic acid unit. This biomass PET may be formed only of PET having biomass-derived ethylene glycol as a diol unit and fossil fuel-derived dicarboxylic acid as a dicarboxylic acid unit, or may be formed from biomass-derived ethylene glycol and fossil fuel-derived diol. It may be formed of PET having a diol unit and a fossil fuel-derived dicarboxylic acid as a dicarboxylic acid unit.

PET used for PET bottles can be obtained by a conventionally known method of polycondensing the diol units and dicarboxylic acid units described above. Specifically, a general method of melt polymerization such as conducting an esterification reaction and/or a transesterification reaction between the diol unit and the dicarboxylic acid unit and then conducting a polycondensation reaction under reduced pressure, or an organic solvent can be produced by a known solution heating dehydration condensation method using

The amount of the diol unit used in the production of the PET is substantially equimolar with respect to 100 mol of the dicarboxylic acid or derivative thereof. Since there is distillation during the reaction, it is used in excess of 0.1 mol % or more and 20 mol % or less.

Moreover, the polycondensation reaction is preferably carried out in the presence of a polymerization catalyst. The timing of adding the polymerization catalyst is not particularly limited as long as it is before the polycondensation reaction, and it may be added at the time of charging the raw materials or at the start of depressurization.

After the PET from recycled PET bottles is polymerized and solidified as described above, solid state polymerization is performed as necessary to further increase the degree of polymerization and remove oligomers such as cyclic trimers. you can go Specifically, in the solid state polymerization, PET is chipped and dried, and then heated at a temperature of 100° C. or higher and 180° C. or lower for about 1 to 8 hours to pre-crystallize the PET, followed by 190° C. It is carried out by heating at a temperature of 230° C. or less in an inert gas atmosphere or under reduced pressure for 1 hour to several tens of hours.

The intrinsic viscosity of PET contained in the base material layer is preferably 0.58 dl/g or more and 0.80 dl/g or less. If the intrinsic viscosity is less than 0.58 dl/g, the mechanical properties required for the PET film as the substrate may be insufficient. On the other hand, when the intrinsic viscosity exceeds 0.80 dl/g, the productivity in the film forming process may be impaired. In addition, the intrinsic viscosity is measured at 35° C. with an orthochlorophenol solution.

The base material layer preferably contains recycled PET at a ratio of 50% by weight or more and 95% by weight or less, and may contain virgin PET in addition to recycled PET. The virgin PET may be PET containing ethylene glycol as the diol unit and containing terephthalic acid and isophthalic acid as the dicarboxylic acid unit as described above, or PET containing no isophthalic acid as the dicarboxylic acid unit. good too. Moreover, the base material layer may contain polyester other than PET. For example, dicarboxylic acid units may include aliphatic dicarboxylic acids and the like in addition to aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid.

Specific examples of aliphatic dicarboxylic acids include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, and cyclohexanedicarboxylic acid, which usually have 2 to 40 carbon atoms. cyclic or alicyclic dicarboxylic acids. Derivatives of aliphatic dicarboxylic acids include lower alkyl esters such as methyl esters, ethyl esters, propyl esters and butyl esters of the above aliphatic dicarboxylic acids, and cyclic acid anhydrides of the above aliphatic dicarboxylic acids such as succinic anhydride. . Among these, as the aliphatic dicarboxylic acid, adipic acid, succinic acid, dimer acid, or a mixture thereof is preferable, and those containing succinic acid as a main component are particularly preferable. More preferred derivatives of aliphatic dicarboxylic acids are methyl esters of adipic acid and succinic acid, or mixtures thereof.

The substrate layer composed of such PET may be a single layer or multiple layers. As shown in FIG. 5, when the recycled PET as described above is used for the base material layer, the base material layer may have three layers of a first layer 51, a second layer 52 and a third layer 53. FIG. In this case, in the laminate, the third layer 53 of the substrate layers is located on the sealant layer side. In this case, the second layer 52 is a layer composed only of recycled PET or a mixed layer of recycled PET and virgin PET, and the first layer 51 and the third layer 53 are layers composed only of virgin PET. preferably. By using only virgin PET for the first layer 51 and the third layer 53 in this manner, it is possible to prevent the recycled PET from being exposed from the front surface or the rear surface of the base material layer. Therefore, the sanitation of the laminate can be ensured. Further, the base layer may be a base layer having two layers, the second layer 52 and the third layer 53, without providing the first layer 51 shown in FIG. Furthermore, the base layer may be a base layer having two layers, the first layer 51 and the second layer 52, without providing the third layer 53 shown in FIG. Also in these cases, the second layer 52 is a layer composed only of recycled PET or a mixed layer of recycled PET and virgin PET, and the first layer 51 and the third layer 53 are layers composed only of virgin PET. It is preferable to

When recycled PET and virgin PET are mixed and molded into one layer, there are a method of feeding them separately to a molding machine, a method of feeding them after mixing by dry blending, and the like. Among them, the method of mixing by dry blending is preferable from the viewpoint of simple operation.

Various additives can be added to the PET constituting the base material layer during the production process or after the production, as long as the properties are not impaired. Additives such as plasticizers, UV stabilizers, color inhibitors, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, thread friction reducing agents, release agents, antioxidants, ions exchange agents, color pigments, and the like. The additive is preferably added in a range of 5% by mass to 50% by mass, preferably 5% by mass to 20% by mass, based on the total resin composition containing PET.

The substrate layer can be formed by forming a film from the PET described above, for example, by a T-die method. Specifically, after drying the above PET, it is supplied to a melt extruder heated to a temperature (Tm) above the melting point of PET to Tm + 70 ° C. to melt the resin composition, for example, a T die A film can be formed by extruding a sheet from a die such as the above, and rapidly cooling and solidifying the extruded sheet with a rotating cooling drum or the like. As the melt extruder, a single-screw extruder, a twin-screw extruder, a vent extruder, a tandem extruder, or the like can be used depending on the purpose.

The film obtained as described above is preferably biaxially stretched. Biaxial stretching can be performed by a conventionally known method. For example, the film extruded onto the cooling drum as described above is subsequently heated by roll heating, infrared heating, or the like, and stretched in the longitudinal direction to obtain a longitudinally stretched film. This stretching is preferably carried out using a difference in circumferential speed between two or more rolls. Longitudinal stretching is usually performed in a temperature range of 50°C or higher and 100°C or lower. Further, the longitudinal stretching ratio is preferably 2.5 times or more and 4.2 times or less, although it depends on the properties required for the film application. If the draw ratio is less than 2.5 times, the thickness unevenness of the PET film becomes large, making it difficult to obtain a good film.

The longitudinally stretched film is then successively subjected to transverse stretching, heat setting, and heat relaxation steps to obtain a biaxially stretched film. Lateral stretching is usually performed in a temperature range of 50°C or higher and 100°C or lower. The lateral stretching ratio is preferably 2.5 times or more and 5.0 times or less, although it depends on the properties required for the application. If it is less than 2.5 times, the thickness of the film becomes uneven, making it difficult to obtain a good film.

After the transverse stretching, heat setting treatment is carried out, and the preferable temperature range for heat setting is Tg+70 to Tm−10° C. of PET. Moreover, the heat setting time is preferably 1 second or more and 60 seconds or less. Furthermore, for applications that require a reduction in heat shrinkage, heat relaxation treatment may be performed as necessary.

The thickness of the PET film obtained as described above is arbitrary according to its use, but is usually about 5 μm to 100 μm, preferably 5 μm to 25 μm. The breaking strength of the PET film is 5 kg/mm ² or more and 40 kg/mm ² or less in the MD direction, and 5 kg/mm ² or more and 35 kg/mm ^{2 or} less in the TD direction. % or more and 350% or less, and 50% or more and 300% or less in the TD direction. Moreover, the shrinkage rate when left in a temperature environment of 150° C. for 30 minutes is 0.1% or more and 5% or less.

Virgin PET may be fossil fuel polyethylene terephthalate (hereinafter also referred to as fossil fuel PET) or biomass PET. As used herein, “fossil fuel PET” has a diol unit derived from a fossil fuel and a dicarboxylic acid derived from a fossil fuel as a dicarboxylic acid unit. Recycled PET may be obtained by recycling PET resin products formed using fossil fuel PET, or obtained by recycling PET resin products formed using biomass PET. There may be.

[Barrier layer]
Next, the barrier layer will be explained.

{First configuration of barrier layer}
A barrier layer according to a first configuration comprises a metal foil. As the metal foil constituting the barrier layer of the laminate shown in FIG. 1, a conventionally known metal foil can be used. Aluminum foil is preferable from the viewpoint of gas barrier properties that prevent permeation of oxygen gas and water vapor, and light shielding properties that prevent permeation of visible light, ultraviolet rays, and the like. The thickness of the metal foil is, for example, 5 μm or more and 15 μm or less. By setting the thickness of the metal foil to 5 μm or more, even if foreign matter adheres to the recycled PET used for the base material layer in the packaging bag including the laminate, the foreign matter is not exposed to the inner surface side of the barrier layer. It is possible to prevent problems that occur. Therefore, the sanitary property of the contents can be ensured.

{Second configuration of barrier layer}
A barrier layer according to a second configuration comprises a vapor deposited film. The vapor-deposited film constituting the barrier layer of the laminate shown in FIGS. membrane.

(Film base layer)
Monoaxially or biaxially stretched thermoplastic resin films such as polyethylene terephthalate (PET), polypropylene (PP), and nylon (ONy) can be suitably used as the film base layer. Moreover, the film base layer may have gas barrier properties. In this case, the gas barrier properties of the laminate as a whole are improved, and in a packaging bag made from this laminate, for example, permeation of oxygen from the outside can be suppressed, and deterioration of the contents due to oxidation can be suppressed. As an example, a film having high gas barrier properties itself, such as saponified ethylene-vinyl acetate copolymer (EVOH), polyvinylidene chloride resin (PVDC), etc., may be used as the film base layer having gas barrier properties. good. The thickness of the film base layer is, for example, 5 μm or more and 30 μm or less. If the thickness of the film substrate layer is less than 5 μm, the breaking strength and tensile strength may be low, and the vapor deposition workability may not be sufficient.

(evaporation layer)
The vapor deposition layer is a layer made of a vapor deposition film that can be formed by a conventionally known method. By providing the vapor deposition layer, it is possible to impart or improve gas barrier properties that prevent permeation of oxygen gas, water vapor, and the like. In addition, the vapor deposition film which comprises a barrier layer may be provided with two or more layers of vapor deposition layers. When two or more deposited layers are provided, they may have the same composition or may have different compositions.

The deposited film may be a metal deposited film made of a metal deposited film, or may be a transparent deposited film made of an inorganic oxide deposited film.

When the barrier layer contains a vapor-deposited metal film, in addition to the gas barrier properties described above, it is possible to impart or improve light-shielding properties that block the transmission of visible light, ultraviolet rays, and the like. Moreover, since it is possible to impart a metallic luster to the packaging bag, it is possible to improve the design. When the barrier layer includes a transparent deposited film, it is possible to impart or improve gas barrier properties that prevent permeation of oxygen gas, water vapor, etc. while maintaining the permeability of the contents.

Examples of metal deposition films include aluminum (Al), magnesium (Mg), tin (Sn), sodium (Na), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), gold ( Au), chromium (Cr), etc. can be used. In particular, for packaging bags, it is preferable to provide an aluminum deposition film.

Although the film thickness of the metal vapor deposition film varies depending on the type of metal used, it is desirable to select and form it within the range of, for example, 50 Å or more and 2000 Å or less, preferably 100 Å or more and 1000 Å or less. More specifically, in the case of a deposited aluminum film, the film thickness is desirably 50 Å or more and 600 Å or less, more preferably 100 Å or more and 450 Å or less.

Examples of transparent deposition films include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium ( Ti), lead (Pb), zirconium (Zr), yttrium (Y), and other oxide films can be used. In particular, for packaging bags, it is preferable to have a deposited film of aluminum oxide or silicon oxide.

Inorganic oxides are represented by MO _X such as SiO _X and AlO _X (wherein M represents an inorganic element, and the value of X varies depending on the inorganic element). expressed. The range of values of X is 0 to 2 for silicon (Si), 0 to 1.5 for aluminum (Al), 0 to 1 for magnesium (Mg), 0 to 1 for calcium (Ca), Potassium (K) is 0 to 0.5, Tin (Sn) is 0 to 2, Sodium (Na) is 0 to 0.5, Boron (B) is 0 to 1.5, Titanium (Ti) can range from 0 to 2, lead (Pb) from 0 to 2, zirconium (Zr) from 0 to 2, and yttrium (Y) from 0 to 1.5. In the above, when X=0, it is a completely inorganic substance (pure substance) and not transparent, and the upper limit of the range of X is the fully oxidized value. Silicon (Si) and aluminum (Al) are preferably used for packaging materials, with silicon (Si) in the range of 1.0 to 2.0 and aluminum (Al) in the range of 0.5 to 1.5. values can be used.

The film thickness of the transparent deposited film varies depending on the type of inorganic oxide used, etc., but it is desirable to select and form it within the range of, for example, 50 Å or more and 2000 Å or less, preferably 100 Å or more and 1000 Å or less. For example, in the case of a deposited film of aluminum oxide or silicon oxide, the film thickness is desirably 50 Å or more and 500 Å or less, more preferably 100 Å or more and 300 Å or less.

The vapor deposition film can be formed on the substrate layer or the like using the following forming method. Examples of methods for forming a deposited film include physical vapor deposition methods such as vacuum deposition, sputtering, and ion plating (physical vapor deposition, PVD), plasma chemical vapor deposition, thermochemical vapor deposition, and the like. A chemical vapor deposition method (Chemical Vapor Deposition method, CVD method) such as a chemical vapor deposition method and a photochemical vapor deposition method can be used.

(Gas barrier coating film)
If necessary, a gas barrier coating film may be provided on the vapor deposition layer. The gas-barrier coating film is a coating film that functions as a layer that suppresses permeation of oxygen gas, water vapor, and the like. The gas barrier coating film has the general formula R ¹ _n M (OR ² ) _m (wherein R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the valence of M.) and at least one or more alkoxides represented by ), a polyvinyl alcohol-based resin and / or It contains an ethylene-vinyl alcohol copolymer and is obtained by polycondensation by the sol-gel method in the presence of a sol-gel catalyst, acid, water and an organic solvent.

As the alkoxide represented by the general formula R ¹ _n M(OR ² ) _m , at least one of partial hydrolyzate of alkoxide and condensate of hydrolysis of alkoxide can be used. The partial hydrolyzate of the above alkoxide does not need to have all of the alkoxy groups hydrolyzed, and may be those in which one or more alkoxy groups are hydrolyzed, or a mixture thereof. As the condensate obtained by hydrolysis of alkoxide, a partially hydrolyzed alkoxide dimer or higher, specifically a dimer to hexamer, is used.

In the alkoxide represented by the general formula R ¹ _n M(OR ² ) _m , the metal atom represented by M can be silicon, zirconium, titanium, aluminum, or the like. In this embodiment, preferred metals include, for example, silicon and titanium. In the present invention, alkoxides can be used either singly or as a mixture of alkoxides of two or more different metal atoms in the same solution.

Further, in the alkoxide represented by the general formula R ¹ _n M(OR ² ) _m , specific examples of the organic group represented by R ¹ include a methyl group, an ethyl group, an n-propyl group, i -propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-hexyl group, n-octyl group, and the like. Further, in the alkoxide represented by the general formula R ¹ _n M(OR ² ) _m , specific examples of the organic group represented by R ² include a methyl group, an ethyl group, an n-propyl group, i -propyl group, n-butyl group, sec-butyl group, and the like. These alkyl groups may be the same or different in the same molecule.

For example, a silane coupling agent may be added when preparing the gas barrier composition. Known organic reactive group-containing organoalkoxysilanes can be used as the silane coupling agent. In this embodiment, organoalkoxysilanes having an epoxy group are particularly preferably used. Specifically, examples include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β -(3,4-Epoxycyclohexyl)ethyltrimethoxysilane and the like can be used. The above silane coupling agents may be used singly or in combination of two or more.

{Third configuration of barrier layer}
A barrier layer according to a third configuration includes a saponified ethylene-vinyl acetate copolymer (EVOH). As the EVOH constituting the barrier layer of the laminate shown in FIG. 4, for example, one described in JP-A-2008-307847 can be used. The thickness of the barrier layer according to the third configuration is preferably 5 μm or more and 40 μm or less, more preferably 10 μm or more and 35 μm or less. By setting the thickness of the barrier layer to 5 μm or more, even if foreign matter adheres to the recycled PET used for the base material layer in the packaging bag including the laminate, the foreign matter is exposed to the inner surface side of the barrier layer. It is possible to prevent troubles that occur. Therefore, the sanitary property of the contents can be ensured.

Note that two or more barrier layers may be provided as described above. When there are two or more barrier layers, they may have the same composition or different compositions.

[Sealant layer]
The sealant layer is the innermost layer in the package. The sealant layer is a layer formed of a thermoplastic resin that can be fused together by heat. The sealant layer may contain a resin material derived from fossil fuel, or may contain a resin material derived from biomass.

The resin material forming the sealant layer is not particularly limited as long as it is a resin that can be mutually fused by heat. High-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), ethylene-α-olefin copolymer polymerized using a metallocene catalyst, random or block copolymer of ethylene-polypropylene, polypropylene, Ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate Copolymers (EMMA), ionomer resins, heat-sealable ethylene-vinyl alcohol resins, or polyolefins such as methylpentene-based resins, ethylene-propylene copolymers, methylpentene polymers, polybutene polymers, polyethylene, polypropylene or cyclic olefin copolymers acid-modified polyolefin resins, poly(vinyl acetate) resins, poly(meth)acryl resins, polyvinyl chloride resins, and other resins. These may be used alone or as a mixture of two or more. The sealant layer can be used as a resin film or sheet as described above, or as a coating film thereof.

When polyethylene is used as the resin material for forming the sealant layer, it may be obtained by polymerizing biomass-derived ethylene in addition to ethylene obtained from fossil fuels. As the biomass-derived ethylene, specifically, for example, one described in JP-A-2012-251006 can be used. By using polyethylene obtained by polymerizing biomass-derived ethylene as a material for forming the sealant layer, it is possible to form a layer made of a carbon-neutral material. can reduce the amount used and reduce the environmental load.

As the biomass-derived ethylene, commercially available ones may be used, for example, Braskem's "C4LL-LL118 (d = 0.916, MFR = 1.0 g / 10 minutes)" sugarcane-derived linear A low-density polyethylene-based resin or a sugarcane-derived low-density polyethylene-based resin such as "SBC118 (d=0.918, MFR=8.1 g/10 min)" can be used.

In this embodiment, one sealant layer is provided, but two or more sealant layers may be provided. When there are two or more sealant layers, each layer may have the same composition or different compositions. For example, the sealant layer is composed of three layers in which a first layer, a second layer and a third layer are laminated in order, the first layer and the third layer are made of a fossil fuel-derived resin material, and the second layer is made of a resin material derived from fossil fuel. The layer may be made of a resin material containing a biomass-derived resin material. When the sealant layer is composed of two or more layers, they can be laminated using a co-extrusion method.

The thickness of the sealant layer is preferably 20 μm or more and 200 μm or less, more preferably 30 μm or more and 130 μm or less.

[Adhesion layer]
The adhesive layer is a layer provided when any two layers are adhered, and can be provided, for example, between the base material layer and the barrier layer or between the barrier layer and the sealant layer.

The adhesive layer can be an adhesive layer formed by applying an adhesive to the surface of the layer on the side to be laminated and drying it when two layers are adhered by a dry lamination method. Examples of adhesives include one-component or two-component curing or non-curing vinyl, (meth)acrylic, polyamide, polyester, polyether, polyurethane, epoxy, rubber, and others. A solvent-type, water-based, or emulsion-type adhesive can be used. A cured product of a polyol and an isocyanate compound can be used as the two-liquid curing adhesive. Examples of coating methods for the lamination adhesive include a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fontaine method, a transfer roll coating method, and other methods. .

The adhesive layer may be an adhesive resin layer used when bonding two layers by a sand lamination method. Thermoplastic resins that can be used for the adhesive resin layer include polyethylene-based resins, polypropylene-based resins, cyclic polyolefin-based resins, or copolymer resins, modified resins, or mixtures (including alloys) containing these resins as main components. ) can be used. Polyolefin resins include, for example, low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP), metallocene catalyst Ethylene-α-olefin copolymer, ethylene-polypropylene random or block copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-α-olefin copolymer polymerized using Ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, ionomer resin, adhesion between layers In order to improve the above, it is possible to use an acid-modified polyolefin resin obtained by modifying the above polyolefin resin with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, or itaconic acid. can. Further, a resin obtained by graft polymerization or copolymerization of an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride, or an ester monomer can be used as the polyolefin resin. These materials can be used singly or in combination of two or more. Cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbonene can be used as cyclic polyolefin resins. These resins can be used singly or in combination. As the polyethylene-based resin described above, the biomass content can be further improved by using the above-described biomass-derived ethylene as a monomer unit.

When the adhesive resin layer is laminated by the melt extrusion lamination method, an anchor coat layer formed by applying an anchor coat agent and drying it may be provided on the surface of the layer to be laminated. The anchor coating agent includes any resin having a heat resistance temperature of 135° C. or higher, such as an anchor coating agent made of vinyl-modified resin, epoxy resin, urethane resin, polyester resin, polyethyleneimine, etc. Especially, An anchor coating agent which is a cured product of a polyacrylic or polymethacrylic resin (polyol) having two or more hydroxyl groups and an isocyanate compound as a curing agent can be preferably used. In addition, a silane coupling agent may be used together as an additive, and nitrocellulose may be used together to improve heat resistance.

The number of adhesive layers in the laminate may be one, or two or more may be included. For example, when two adhesive layers are included in the laminate, one adhesive layer may be referred to as the first adhesive layer, and the other adhesive layer may be referred to as the second adhesive layer.

The anchor coat layer after drying has a thickness of 0.1 μm or more and 1 μm or less, preferably 0.3 μm or more and 0.5 μm or less. The dried adhesive layer has a thickness of 1 μm or more and 10 μm or less, preferably 2 μm or more and 5 μm or less. The adhesive resin layer preferably has a thickness of 5 μm or more and 50 μm or less, preferably 10 μm or more and 30 μm or less.

[Other layers]
The laminate according to the present invention may further include a printed layer or the like as another layer. The printed layer contains letters, numbers, patterns, figures, symbols, patterns, etc. It is a layer that forms any desired printed pattern. The print layer can be provided as necessary, for example, it can be provided between the base material layer and the barrier layer. The printed layer may be provided on the entire surface of the base material layer, or may be provided on a part thereof. The print layer can be formed using conventionally known pigments and dyes, and the formation method is not particularly limited.

The print layer preferably has a thickness of 0.1 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less, still more preferably 1 μm or more and 3 μm or less.

<Method for manufacturing laminate>
The method for producing the laminate according to the present invention is not particularly limited, and the laminate can be produced using a conventionally known method such as a dry lamination method.

The laminate according to the present invention is imparted with chemical functions, electrical functions, magnetic functions, mechanical functions, friction/wear/lubricating functions, optical functions, thermal functions, surface functions such as biocompatibility, and the like. For the purpose, it is also possible to apply secondary processing. Examples of secondary processing include embossing, painting, adhesion, printing, metallizing (plating, etc.), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.). Also, the laminate according to the present invention can be subjected to lamination (dry lamination or extrusion lamination), bag making, and other post-treatments to produce a molded product.

The laminate can be used, for example, as a packaging bag filled with products such as food. For example, using the above laminate, folding it in two, or preparing two laminates, overlapping the sealant surfaces with each other, and further sealing the peripheral edge thereof, for example, a side seal type , 2-side seal type, 3-side seal type, 4-side seal type, envelope seal type, palm seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, gusset type, etc. By heat-sealing with, various forms of packaging bags can be produced.

In the above, the heat sealing can be carried out by known methods such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing and ultrasonic sealing.

Since the packaging bag has excellent hygienic properties while reducing the burden on the environment, it can be suitably used as a packaging bag for hermetically packaging foods and the like.

(Other aspects)
Another aspect of the present invention is a laminate comprising at least a base layer, a barrier layer and a sealant layer in this order, wherein the base layer contains ethylene glycol as a diol unit, terephthalic acid and isophthalic acid. is a laminate comprising polyethylene terephthalate having dicarboxylic acid units, and the barrier layer comprising a metal foil.

Another aspect of the present invention is a laminate comprising at least a base layer, a barrier layer and a sealant layer in this order, wherein the base layer contains ethylene glycol as a diol unit, terephthalic acid and isophthalic acid. is a laminate comprising polyethylene terephthalate having a dicarboxylic acid unit of and the barrier layer comprising a vapor deposited film.

In the laminate according to another aspect of the present invention, the barrier layer may contain a metal-deposited film.

In the laminate according to another aspect of the present invention, the barrier layer may contain a transparent deposition film.

Another aspect of the present invention is a laminate comprising at least a base layer, a barrier layer and a sealant layer in this order, wherein the base layer contains ethylene glycol as a diol unit, terephthalic acid and isophthalic acid. is a laminate comprising polyethylene terephthalate having dicarboxylic acid units, and the barrier layer comprising a saponified ethylene-vinyl acetate copolymer.

In the laminate according to another aspect of the present invention, the isophthalic acid content may be 0.5 mol % or more and 5.0 mol % or less with respect to all dicarboxylic acid units constituting the polyethylene terephthalate. .

In the laminate according to another aspect of the present invention, the intrinsic viscosity of the polyethylene terephthalate may be 0.58 dl/g or more and 0.80 dl/g or less.

REFERENCE SIGNS LIST 10 laminate 11 substrate layer 12 barrier layer 13 sealant layer 121 metal foil 20 laminate 21 substrate layer 22 barrier layer 23 sealant layer 220 deposited film 30 laminate 31 substrate layer 32 barrier layer 33 sealant layer 321 ethylene-vinyl acetate saponified copolymer

Claims (7)

A laminate comprising at least a substrate layer, a barrier layer, and a sealant layer in this order,
The substrate layer comprises a first layer, a second layer (excluding those containing an antistatic agent) , and a third layer in this order,
The first layer and the third layer are layers composed only of virgin fossil fuel polyethylene terephthalate,
The second layer is a layer composed only of recycled polyethylene terephthalate or a mixed layer of recycled polyethylene terephthalate and virgin polyethylene terephthalate,
The recycled polyethylene terephthalate includes polyethylene terephthalate having ethylene glycol as a diol unit and terephthalic acid and isophthalic acid as dicarboxylic acid units,
The barrier layer comprises a vapor deposited film,
The base material layer contains recycled polyethylene terephthalate at a ratio of 50% by weight or more and 95% by weight or less,
The thickness of the base material layer is 5 μm or more and 25 μm or less,
The laminate, wherein the substrate layer is a biaxially stretched film. 2. The laminate of Claim 1, wherein the barrier layer comprises a metallized film. 2. The laminate of Claim 1, wherein the barrier layer comprises a transparent vapor deposited film. A laminate comprising at least a substrate layer, a barrier layer, and a sealant layer in this order,
The base material layer includes virgin polyethylene terephthalate and recycled polyethylene terephthalate containing polyethylene terephthalate having ethylene glycol as a diol unit and terephthalic acid and isophthalic acid as dicarboxylic acid units,
The base material layer does not contain a biomass polyester resin having a biomass-derived ethylene glycol as a diol unit and a fossil fuel-derived dicarboxylic acid as a dicarboxylic acid unit,
The barrier layer contains a saponified ethylene-vinyl acetate copolymer,
The thickness of the base material layer is 5 μm or more and 25 μm or less,
The laminate, wherein the substrate layer is a biaxially stretched film. 5. The content of the isophthalic acid according to any one of claims 1 to 4, wherein the content of the isophthalic acid is 0.5 mol% or more and 5.0 mol% or less with respect to all dicarboxylic acid units constituting the polyethylene terephthalate. laminate. The laminate according to any one of claims 1 to 5, wherein the intrinsic viscosity of the polyethylene terephthalate is 0.58 dl/g or more and 0.80 dl/g or less. A packaging bag comprising the laminate according to any one of claims 1 to 6.

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