JP7001989B2 - Laminate - Google Patents

Description

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

Plastic, which is a fossil fuel-derived material, is mainly used in the manufacture of packaging materials for filling products such as pharmaceuticals, cosmetics, and foods from the viewpoint of ease of molding and cost. Polyester-based resins, polyolefin-based resins, polyamide-based resins, and the like are used as plastic materials that are 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 polycondensing a diol unit and a dicarboxylic acid unit. For example, polyethylene terephthalate (hereinafter, may be 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 movement year by year to reduce the use of fossil fuels for various purposes in consideration of the environment and to reduce CO ₂ emissions. As an attempt to reduce the use of such 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 of packaging materials (). For example, see Patent Documents 1 and 2). In Patent Documents 1 and 2, CO ₂ emissions are reduced by using polyester as a part of the packaging material, which is made by recovering used products formed from fossil fuel-derived polyester so that they can be reused. It is proposed to try.

Japanese Unexamined Patent Publication No. 2011-256328 Japanese Unexamined Patent Publication No. 2012-41463

However, packaging materials using recycled PET recycled by mechanical recycling, in which recovered PET bottles and other polyester resin products are crushed, washed and reused, are contaminated due to foreign matter adhering to the recycled PET. There is an impression that nations may have occurred. For this reason, it is difficult to obtain the trust of consumers for packaging materials manufactured by using a laminated body made of recycled PET, particularly packaging materials for filling products such as foods.

An object of the present invention is to provide a laminate capable of effectively solving such a problem.

The present invention is a laminate including at least a base material layer and a sealant layer in this order, and the base material layer is polyethylene having ethylene glycol as a diol unit and terephthalic acid and isophthalic acid as a dicarboxylic acid unit. The sealant layer containing terephthalate is a laminate having a plurality of layers, and at least one of the plurality of layers is a barrier resin layer.

In the laminate according to the present invention, the sealant layer is the surface of the first thermoplastic resin layer provided on the surface of the barrier resin layer opposite to the base material layer and the surface of the barrier resin layer. Of these, it may have a second thermoplastic resin layer provided on the surface of the base material layer side.

In the laminate according to the present invention, the sealant layer is a third thermoplastic resin layer located between the barrier resin layer and the first thermoplastic resin layer, and the barrier resin layer and the second thermoplastic. It may have a fourth thermoplastic resin layer located between the resin layer and the resin layer.

In the laminate according to the present invention, the barrier resin layer may contain a saponified product of an ethylene-vinyl acetate copolymer.

In the laminate according to the present invention, the barrier resin layer may contain a polyamide.

In the laminate according to the present invention, the barrier resin layer may contain polyvinyl alcohol.

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

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

According to the present invention, it is possible to provide a laminated body having an excellent CO ₂ reduction effect and excellent hygiene as compared with a laminated body made of polyethylene terephthalate which is not recycled.

It is a schematic sectional drawing which shows an example of the laminated body by this invention. It is a schematic sectional drawing which shows an example of the laminated body by this invention. It is a schematic cross-sectional view which shows an example of the base material layer of the laminated body by this invention.

<Laminated body>
The laminate according to the present invention includes at least a base material layer and a sealant layer in this order. The laminate may further include an adhesive layer, a print layer, another layer, and the like. When the laminate includes two or more adhesive layers and other layers, each of them may have the same composition or different compositions.

The laminated body according to the present invention will be described with reference to the drawings. Examples of schematic cross-sectional views of the laminated body according to the present invention are shown in FIGS. 1 to 6.

The laminate 10 shown in FIG. 1 includes a base material layer 11, an adhesive layer 13, a second thermoplastic resin layer 123 constituting the sealant layer 12, a barrier resin layer 121 constituting the sealant layer 12, and a sealant. The first thermoplastic resin layer 122 constituting the layer 12 is provided in this order. In the packaging bag provided with the laminate 10, the first thermoplastic resin layer 122 constituting the sealant layer 12 is located on the innermost surface.

The laminate 20 shown in FIG. 2 includes a base material layer 21, an adhesive layer 23, a second thermoplastic resin layer 223 constituting the sealant layer 22, and a fourth thermoplastic resin layer 225 constituting the sealant layer 22. , The barrier resin layer 221 constituting the sealant layer 22, the third thermoplastic resin layer 224 constituting the sealant layer 22, and the first thermoplastic resin layer 222 constituting the sealant layer 22 are provided in this order. In the packaging bag provided with the laminate 20, the first thermoplastic resin layer 222 constituting the sealant layer 22 is located on the innermost surface.

Hereinafter, each layer constituting the laminated body will be described.

[Base 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 in which PET bottles are recycled by mechanical recycling, in which the diol unit is ethylene glycol and the dicarboxylic acid unit contains terephthalic acid and isophthalic acid. Here, mechanical recycling generally means that the collected polyethylene terephthalate resin products such as PET bottles are crushed and alkaline-cleaned to remove stains and foreign substances on the surface of the PET resin products, and then dried under high temperature and reduced pressure for a certain period of time. This is a method in which the contaminants remaining inside the PET resin are diffused and decontaminated, the stains on the resin product made of the PET resin are removed, and the resin is returned to the PET resin again. Hereinafter, in the present specification, polyethylene terephthalate obtained by recycling PET bottles is referred to as "recycled polyethylene terephthalate (hereinafter, also referred to as recycled PET)", and non-recycled polyethylene terephthalate is referred to as "virgin polyethylene terephthalate (hereinafter, also referred to as virgin PET)". ) ”.

Of 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, preferably 1.0 mol%, based on all the dicarboxylic acid units constituting the PET. It is more preferably 2.5 mol% or more. If the content of isophthalic acid is less than 0.5 mol%, the flexibility may not be improved, while if it exceeds 5 mol%, the melting point of PET may be lowered and the heat resistance may be insufficient. The PET may be a biomass PET as well as a PET derived from a normal fossil fuel. The "biomass PET" contains ethylene glycol derived from biomass as a diol unit and contains a dicarboxylic acid derived from fossil fuel as a dicarboxylic acid unit. This biomass PET may be formed only of PET having a biomass-derived ethylene glycol as a diol unit and a fossil fuel-derived dicarboxylic acid as a dicarboxylic acid unit, or a biomass-derived ethylene glycol and a fossil fuel-derived diol. It may be formed of PET having a diol unit and a dicarboxylic acid derived from fossil fuel as a dicarboxylic acid unit.

The PET used in the PET bottle can be obtained by a conventionally known method of polycondensing the above-mentioned diol unit and dicarboxylic acid unit. Specifically, a general method of melt polymerization such as performing an esterification reaction and / or an ester exchange reaction between the above diol unit and a dicarboxylic acid unit and then performing a polycondensation reaction under reduced pressure, or an organic solvent. It can be produced by a known solution heating dehydration condensation method or the like using the above.

The amount of the diol unit used in producing the PET is substantially equimolar to 100 mol of the dicarboxylic acid or its derivative, but generally, esterification and / or transesterification reaction and / or depolymerization. Since there is distillation during the reaction, it is used in excess of 0.1 mol% or more and 20 mol% or less.

Further, 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 reduced pressure.

PET bottles recycled from PET bottles are polymerized and solidified as described above, and then solid-phase polymerization is performed as necessary in order to further increase the degree of polymerization and remove oligomers such as cyclic trimers. You may go. Specifically, in solid phase polymerization, the 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 lower for 1 hour to several tens of hours under an inert gas atmosphere or under reduced pressure.

The ultimate 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 ultimate viscosity is less than 0.58 dl / g, the mechanical properties required for the PET film as a base material may be insufficient. On the other hand, if the ultimate viscosity exceeds 0.80 dl / g, the productivity in the film forming process may be impaired. The ultimate viscosity is measured with an orthochlorophenol solution at 35 ° C.

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

Specific examples of the aliphatic dicarboxylic acid include chains having 2 or more and 40 or less carbon atoms, such as oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid and cyclohexanedicarboxylic acid. The shape or alicyclic dicarboxylic acid can be mentioned. Examples of the derivative of the aliphatic dicarboxylic acid include lower alkyl esters such as the methyl ester of the aliphatic dicarboxylic acid, ethyl ester, propyl ester and butyl ester, and cyclic acid anhydride of the aliphatic dicarboxylic acid such as succinic anhydride. .. Among these, as the aliphatic dicarboxylic acid, adipic acid, succinic acid, dimer acid or a mixture thereof is preferable, and one containing succinic acid as a main component is particularly preferable. As the derivative of the aliphatic dicarboxylic acid, methyl esters of adipic acid and succinic acid, or mixtures thereof are more preferable.

The base material layer composed of such PET may be a single layer or a multilayer layer. As shown in FIG. 3, when the recycled PET as described above is used as the base material layer, the base material layer may be provided with three layers of the first layer 31, the second layer 32, and the third layer 33. In this case, in the laminated body, the third layer 33 of the base material layer is located on the sealant layer side. Further, in this case, the second layer 32 is a layer composed only of recycled PET or a mixed layer of recycled PET and virgin PET, and the first layer 31 and the third layer 33 are a layer composed only of virgin PET. It is preferable to do so. As described above, by using only virgin PET for the first layer 31 and the third layer 33, it is possible to prevent the recycled PET from being exposed from the front surface or the back surface of the base material layer. Therefore, the hygiene of the laminated body can be ensured. Further, the base material layer may be a base material layer including two layers of the first layer 31 and the second layer 32 without providing the third layer 33 shown in FIG. Further, the base material layer may be a base material layer including two layers of the first layer 31 and the second layer 32 without providing the third layer 33 shown in FIG. Also in these cases, the second layer 32 is a layer composed only of recycled PET or a mixed layer of recycled PET and virgin PET, and the first layer 31 and the third layer 33 are layers composed only of virgin PET. Is preferable.

When one layer is formed by mixing recycled PET and virgin PET, there are a method of separately supplying to a molding machine, a method of supplying after mixing with a dry blend or the like, and the like. Above all, a method of mixing with a dry blend is preferable from the viewpoint of easy operation.

Various additives can be added to the PET constituting the base material layer in the manufacturing process thereof or after the manufacturing thereof as long as the characteristics are not impaired. Additives include, for example, plasticizers, UV stabilizers, color inhibitors, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, thread friction reducing agents, mold release agents, antioxidants, ions. Examples include replacement agents and colored pigments. The additive is preferably added in the range of 5% by mass or more and 50% by mass or less, preferably 5% by mass or more and 20% by mass or less, based on the entire resin composition containing PET.

The base material layer can be formed by, for example, forming a film by the T-die method using the above-mentioned PET. Specifically, after the above-mentioned PET is dried, it is supplied to a melt extruder heated to a temperature equal to or higher than the melting point of PET (Tm) to Tm + 70 ° C. to melt the resin composition, for example, T-die. A film can be formed by extruding a sheet-like material from a die such as a die and quenching and solidifying the extruded sheet-like material 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 and 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 vertical direction to obtain a vertically stretched film. This stretching is preferably performed by utilizing the difference in peripheral speed between two or more rolls. The longitudinal stretching is usually performed in a temperature range of 50 ° C. or higher and 100 ° C. or lower. The magnification of longitudinal stretching is preferably 2.5 times or more and 4.2 times or less, although it depends on the required characteristics of the film application. When the draw ratio is less than 2.5 times, the thickness unevenness of the PET film becomes large and it is difficult to obtain a good film.

The vertically stretched film is subsequently subjected to each of the treatment steps of lateral stretching, heat fixing, and heat relaxation to obtain a biaxially stretched film. The transverse stretching is usually performed in a temperature range of 50 ° C. or higher and 100 ° C. or lower. The ratio of lateral stretching depends on the required characteristics of this application, but is preferably 2.5 times or more and 5.0 times or less. If it is less than 2.5 times, the thickness unevenness of the film becomes large and it is difficult to obtain a good film, and if it exceeds 5.0 times, breakage is likely to occur during film formation.

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

The thickness of the PET film obtained as described above is arbitrary depending on the intended use, but is usually 5 μm or more and 100 μm or less, preferably 5 μm or more and 25 μm or less. 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, 5 kg / mm 2 or more and 35 kg / mm 2 or less} in the TD direction, and the breaking elongation is 50 in the MD direction. % Or more and 350% or less, and 50% or more and 300% or less in the TD direction. The shrinkage rate when left in a temperature environment of 150 ° C. for 30 minutes is 0.1% or more and 5% or less.

The virgin PET may be fossil fuel polyethylene terephthalate (hereinafter, also referred to as fossil fuel PET) or biomass PET. Here, the "fossil fuel PET" is a fossil fuel-derived diol as a diol unit and a fossil fuel-derived dicarboxylic acid as a dicarboxylic acid unit. Further, the recycled PET may be obtained by recycling a PET resin product formed by using fossil fuel PET, or may be obtained by recycling a PET resin product formed by using biomass PET. There may be.

[Sealant layer]
The sealant layer is the innermost layer when it is used as a package. The sealant layer includes a layer formed of a thermoplastic resin that can be fused to each other by heat. The sealant layer may contain a resin material derived from fossil fuel or may contain a resin material derived from biomass.

The sealant layer has at least a barrier resin layer and a first thermoplastic resin layer provided on the surface of the barrier resin layer opposite to the base material layer. By having the barrier resin layer, even if foreign matter adheres to the recycled PET used for the base material layer when the packaging bag is manufactured using the laminated body, the foreign matter adheres to the inner surface of the barrier resin layer. It is possible to prevent problems that appear on the side. Therefore, the hygiene of the contents can be ensured. Further, the sealant layer may have a second thermoplastic resin layer provided on the surface of the barrier resin layer on the side of the base material layer. By having the second thermoplastic resin layer, it is possible to suppress the occurrence of warpage in the film when a film composed of a plurality of resin material layers is produced as the sealant layer. The sealant layer is a fourth thermoplastic resin layer located between the barrier resin layer and the first thermoplastic resin layer, and a fourth thermoplastic resin layer located between the barrier resin layer and the second thermoplastic resin layer. It may have a thermoplastic resin layer. Although not shown, the sealant layer is between the barrier resin layer and the first thermoplastic resin layer, between the barrier resin layer and the second thermoplastic resin layer, and between the first thermoplastic resin layer and the third thermoplastic resin layer. It may further have an adhesion auxiliary layer which is located between the thermoplastic resin layer and / or between the second thermoplastic resin layer and the fourth thermoplastic resin layer and assists the adhesion between the layers. Further, such a sealant layer can be laminated by using a co-extrusion method.

Next, each layer constituting the sealant layer will be described.

(Barrier resin layer)
The barrier resin layer contains a saponified product (EVOH) of an ethylene-vinyl acetate copolymer. As the EVOH constituting the barrier resin layer, for example, those described in JP-A-2008-307847 can be used. The thickness of the barrier resin layer is preferably 1 μm or more and 30 μm or less, and more preferably 3 μm or more and 25 μm or less. By setting the thickness of the barrier resin layer to 1 μm or more, even if foreign matter adheres to the recycled PET used for the base material layer in the packaging bag provided with the laminated body, the foreign matter is more than the barrier resin layer. It is possible to prevent problems that appear on the inner surface side. Therefore, the hygiene of the contents can be ensured.

Further, the barrier resin layer may be a resin layer containing a polyamide such as nylon. In this case, the barrier resin layer is preferably stretched, and more preferably biaxially stretched. Examples of the polyamide include nylon 6, nylon 6,6, nylon 9, nylon 11, nylon 12, nylon 6/66, nylon 66/610, nylon MXD6 and the like. Of these, the barrier resin layer is preferably a resin layer containing nylon MXD6. When the barrier resin layer contains nylon MXD6, the barrier property of the barrier resin layer can be improved. The thickness of the barrier resin layer is preferably 1 μm or more and 30 μm or less, and more preferably 3 μm or more and 25 μm or less. By setting the thickness of the barrier resin layer to 1 μm or more, even if foreign matter adheres to the recycled PET used for the base material layer in the packaging bag provided with the laminated body, the foreign matter is more than the barrier resin layer. It is possible to prevent problems that appear on the inner surface side. Therefore, the hygiene of the contents can be ensured.

Further, the barrier resin layer may be a resin layer containing polyvinyl alcohol. In this case, the thickness of the barrier resin layer is preferably 1 μm or more and 30 μm or less, and more preferably 3 μm or more and 25 μm or less. By setting the thickness of the barrier resin layer to 1 μm or more, even if foreign matter adheres to the recycled PET used for the base material layer in the packaging bag provided with the laminated body, the foreign matter is more than the barrier resin layer. It is possible to prevent problems that appear on the inner surface side, and to ensure the hygiene of the contents.

(1st thermoplastic resin layer)
Specific examples of the resin material forming the first thermoplastic resin layer include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and linear (linear) low. Density polyethylene (LLDPE), ethylene-α / olefin copolymer polymerized using 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 copolymer (EMMA), ionomer resin, heat-sealing ethylene -Vinyl alcohol resin or copolymerized resin Methylpentene resin, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, polyethylene, polypropylene or cyclic olefin copolymer or other polyolefin resin, polyolefin resin is acrylic acid, Acid-modified polyolefin resin modified with unsaturated carboxylic acids such as methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, polyvinyl acetate resin, poly (meth) acrylic resin, polyvinyl chloride resin, etc. Examples include resins such as. These may be used alone or as a mixture of two or more. The first thermoplastic resin layer can be used as a film or sheet of the resin as described above, a coating film thereof, or the like.

When polyethylene is used as the resin material for forming the first thermoplastic resin layer, polyethylene derived from biomass may be polymerized in addition to ethylene obtained from fossil fuel as the raw material. As the biomass-derived ethylene, specifically, for example, those described in JP2012-251006 can be used. By using polyethylene obtained by polymerizing biomass-derived ethylene as a material constituting the first thermoplastic resin layer, it can be formed into a layer made of a carbon-neutral material. Furthermore, the amount of fossil fuel used can be reduced, and the environmental load can be reduced.

As the polyethylene derived from biomass, commercially available polyethylene may be used. For example, a linear sugarcane-derived polyethylene of "C4LL-LL118 (d = 0.916, MFR = 1.0 g / 10 minutes)" manufactured by Braskem Co., Ltd. may be used. A low-density polyethylene-based resin or a sugarcane-derived low-density polyethylene-based resin of "SBC118 (d = 0.918, MFR = 8.1 g / 10 minutes)" can be used.

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

(Second thermoplastic resin layer)
The resin material forming the second thermoplastic resin layer is not particularly limited as long as it is a resin that can be fused to each other by heat, and specifically, for example, low-density polyethylene (LDPE) and medium-density polyethylene (LDPE) and medium-density polyethylene ( MDPE), high density polyethylene (HDPE), linear (linear) low density polyethylene (LLDPE), ethylene-α / olefin copolymer polymerized using a metallocene catalyst, random or block copolymer of ethylene / polypropylene. Combined, polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene -Methyl methacrylate copolymer (EMMA), ionomer resin, heat-sealing ethylene / vinyl alcohol resin, or copolymerized resin methylpentene-based resin, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, polyethylene, Polyolefin-based resins such as polypropylene or cyclic olefin copolymers, acid-modified polyolefin resins obtained by modifying polyolefin-based resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, polyvinyl acetate. Examples thereof include based resins, poly (meth) acrylic resins, polyvinyl chloride resins, and other resins. These may be used alone or as a mixture of two or more. The second thermoplastic resin layer can be used as a film or sheet of the resin as described above, a coating film thereof, or the like.

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

It is preferable that the second thermoplastic resin layer and the above-mentioned first thermoplastic resin layer are formed of the same resin material and have substantially the same thickness. This makes it possible to prevent the film from being warped when a film composed of a plurality of layers of resin material is produced as the sealant layer.

(Third thermoplastic resin layer)
The third thermoplastic resin layer is a resin layer containing a polyamide such as nylon. The third thermoplastic resin layer is preferably stretched, and more preferably biaxially stretched.

Examples of the polyamide include nylon 6, nylon 6,6, nylon 9, nylon 11, nylon 12, nylon 6/66, nylon 66/610, nylon MXD6 and the like. By providing the polyamide resin layer having inferior water resistance inside the laminate instead of the outside, it is possible to improve the strength required for the packaging bag without impairing the water resistance.

When the third thermoplastic resin layer is a stretched nylon film, the nylon film used for the third thermoplastic resin layer has a tensile strength of preferably 150 MPa or more and 350 MPa or less, more preferably 200 MPa or more and 300 MPa or less in the MD direction. , TD direction, preferably 150 MPa or more and 400 MPa or less, more preferably 200 MPa or more and 350 MPa or less, and MD direction, preferably 50% or more and 200% or less, more preferably 70% or more and 150%. It is preferably 30% or more and 200% or less, and more preferably 50% or more and 150% or less in the TD direction.

The thickness of the third thermoplastic resin layer is preferably 1 μm or more and 30 μm or less, and more preferably 3 μm or more and 25 μm or less.

(4th thermoplastic resin layer)
The fourth thermoplastic resin layer is a resin layer containing a polyamide such as nylon. The fourth thermoplastic resin layer is preferably stretched, and more preferably biaxially stretched. Examples of the polyamide include nylon 6, nylon 6,6, nylon 9, nylon 11, nylon 12, nylon 6/66, nylon 66/610, nylon MXD6 and the like. By providing the polyamide resin layer having inferior water resistance inside the laminate instead of the outside, it is possible to improve the strength required for the packaging bag without impairing the water resistance.

The thickness of the fourth thermoplastic resin layer is preferably 1 μm or more and 30 μm or less, and more preferably 3 μm or more and 25 μm or less.

It is preferable that the fourth thermoplastic resin layer and the above-mentioned third thermoplastic resin layer are formed of the same resin material and have substantially the same thickness. That is, the above-mentioned first thermoplastic resin layer and the second thermoplastic resin layer are formed of the same material, have substantially the same thickness, and have the third thermoplastic resin layer and the fourth heat. Since the thermoplastic resin layer is formed of the same material and has substantially the same thickness, the film is warped when a film composed of a plurality of resin material layers is produced as the sealant layer. Can be suppressed.

(Adhesive auxiliary layer)
The adhesion auxiliary layer is, for example, a resin layer containing modified polyethylene. The adhesive auxiliary layer is between the barrier resin layer and the first thermoplastic resin layer, between the barrier resin layer and the second thermoplastic resin layer, and between the first thermoplastic resin layer and the third thermoplastic resin layer. It is preferably located between and / or between the second thermoplastic resin layer and the fourth thermoplastic resin layer. This adhesive auxiliary layer can assist the adhesion between the layers and improve the adhesiveness between the layers.

Here, an example of a combination of materials constituting the above-mentioned barrier resin layer, first thermoplastic resin layer, second thermoplastic resin layer, third thermoplastic resin layer, fourth thermoplastic resin layer, and adhesion auxiliary layer. They are collectively shown in Tables 1 to 3. In addition, in Tables 1 to 3, "barrier" means a barrier resin layer. Further, the "first", "second", "third" and "fourth" are the first thermoplastic resin layer, the second thermoplastic resin layer, the third thermoplastic resin layer and the fourth thermoplastic resin layer, respectively. Means. Further, "auxiliary" means an adhesive auxiliary layer.

In Tables 1 to 3, "EVOH" means a resin layer containing a saponified product of an ethylene-vinyl acetate copolymer according to the above-mentioned constitution of the barrier resin layer. "Polyamide" means a resin layer containing a polyamide such as nylon, which is related to the composition of the barrier resin layer described above. "PVA" means a resin layer containing polyvinyl alcohol according to the above-mentioned constitution of the barrier resin layer. That is, Table 1 shows the case where the barrier resin layer is a resin layer containing a saponified product of an ethylene-vinyl acetate copolymer, and Table 2 shows a case where the barrier resin layer is a resin layer containing a polyamide such as nylon. A case is shown, and Table 3 shows a case where the barrier resin layer is a resin layer containing polyvinyl alcohol.

Further, in Tables 1 to 3, "PE" means a resin layer containing polyethylene, which is related to the constitution of the first thermoplastic resin layer and the second thermoplastic resin layer described above. "PP" means a resin layer containing polypropylene according to the constitution of the first thermoplastic resin layer and the second thermoplastic resin layer described above. Further, in Tables 1 to 3, "◯" means that the sealant layer includes a third thermoplastic resin layer, a fourth thermoplastic resin and / or an adhesion auxiliary layer, and "x" means that the sealant layer is included. It means that the third thermoplastic resin layer, the fourth thermoplastic resin and / or the adhesion auxiliary layer is not included.

The combinations shown in Tables 1 to 3 above are used as a combination of the barrier resin layer, the first thermoplastic resin layer, the second thermoplastic resin layer, the third thermoplastic resin layer, the fourth thermoplastic resin layer, and the auxiliary layer. Other than that may be adopted.

[Adhesive layer]
The adhesive layer is a layer provided when adhering any two layers, and can be provided between the base material layer and the sealant layer.

When the two layers are bonded by the dry laminating method, 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 the adhesive layer. Examples of the adhesive include one-component or two-component curable or non-curable vinyl-based, (meth) acrylic-based, polyamide-based, polyester-based, polyether-based, polyurethane-based, epoxy-based, rubber-based, and others. An adhesive such as a solvent type, an aqueous type, or an emulsion type can be used. As the two-component curable adhesive, a cured product of a polyol and an isocyanate compound can be used. As a coating method of the above-mentioned laminating adhesive, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a fonten method, a transfer roll coating method, or other methods can be applied. ..

The adhesive layer may be an adhesive resin layer used when the two layers are bonded by the sand laminating method. The thermoplastic resin that can be used for the adhesive resin layer includes a polyethylene resin, a polypropylene resin, a cyclic polyolefin resin, or a copolymer resin containing these resins as a main component, a modified resin, or a mixture (including an alloy). ) Can be used. Examples of the polyolefin resin include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear (linear) low-density polyethylene (LLDPE), polypropylene (PP), and metallocene catalysts. Ethylene-α / olefin copolymer polymerized using, random or block copolymer of ethylene / polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene / Ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, ionomer resin, and adhesion between layers. It is possible to use an acid-modified polyolefin-based resin obtained by modifying the above-mentioned polyolefin-based resin with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid. can. Further, as the polyolefin resin, an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride, a resin obtained by graft-polymerizing or copolymerizing an ester monomer and the like can be used. These materials can be used alone or in combination of two or more. As the cyclic polyolefin resin, for example, a cyclic polyolefin such as an ethylene-propylene copolymer, polymethylpentene, polybutene, or polynorbonene can be used. These resins can be used alone or in combination of two or more. As the polyethylene-based resin described above, a resin using the above-mentioned ethylene derived from biomass as a monomer unit can be used to further improve the degree of biomass.

When laminating the adhesive resin layer by the melt-extruded laminating method, an anchor coat layer formed by applying an anchor coating agent and drying may be provided on the surface of the layer on the laminated side. Examples of the anchor coating agent include any resin having a heat resistant temperature of 135 ° C. or higher, for example, an anchor coating agent made of a vinyl-modified resin, an epoxy resin, a urethane resin, a polyester resin, polyethyleneimine, or the like. An anchor coating agent which is a cured product of a polyacrylic or polymethacrylic resin (polyester) having two or more hydroxyl groups and an isocyanate compound as a curing agent can be preferably used. Further, a silane coupling agent may be used in combination with this as an additive, or nitrified cotton may be used in combination to enhance heat resistance.

The laminated body may have one adhesive layer or may include two or more adhesive layers. For example, when two adhesive layers are included in the laminate, one adhesive layer may be referred to as an adhesive layer and the other adhesive layer may be referred to as a second adhesive layer.

The dried anchor coat layer 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 printing layer or the like as another layer. The printing layer is used for decoration, display of contents, display of best-by date, display of manufacturers, sellers, etc., and for the purpose of giving a sense of beauty, such as letters, numbers, patterns, figures, symbols, and patterns. A layer that forms any desired print pattern. The printed layer can be provided as needed, and can be provided, for example, between the base material layer and the barrier resin layer. The printing layer may be provided on the entire surface of the base material layer, or may be provided on a part of the base material layer. The printed layer can be formed by using a conventionally known pigment or dye, and the forming method thereof is not particularly limited.

The printed 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, and further preferably 1 μm or more and 3 μm or less.

<Manufacturing method of laminated body>
The method for producing the laminate according to the present invention is not particularly limited, and the laminate can be produced by using a conventionally known method such as a dry laminate method.

The laminate according to the present invention is provided with a chemical function, an electrical function, a magnetic function, a mechanical function, a friction / wear / lubrication function, an optical function, a thermal function, a surface function such as biocompatibility, and the like. It is also possible to perform secondary processing for the purpose. 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, etc.) Coating, etc.) and the like. Further, the laminated body according to the present invention may be subjected to laminating processing (dry laminating or extruded laminating), bag making processing, and other post-treatment processing to produce a molded product.

The laminate can be used, for example, in a packaging bag for filling a product such as food. For example, the above laminate is used and folded in half, or two laminates are prepared, the surfaces of the sealants are opposed to each other and overlapped, and the peripheral end thereof is, for example, a side seal type. , Two-way sticker type, three-way sticker type, four-way sticker type, envelope sticker sticker type, gassho sticker sticker type (pillow sticker type), fold sticker type, flat bottom sticker type, square bottom sticker type, gusset type, etc. Can be heat-sealed to produce various forms of packaging bags.

In the above, as the heat sealing method, for example, a known method such as a bar seal, a rotary roll seal, a belt seal, an impulse seal, a high frequency seal, and an ultrasonic seal can be used.

Since the packaging bag has excellent hygiene while reducing the environmental load, it can be particularly suitably used as a packaging bag for sealing and packaging foods and the like.

10 Laminated body 11 Base material layer 12 Sealant layer 121 Barrier resin layer 122 First thermoplastic resin layer 123 Second thermoplastic resin layer 20 Laminated body 21 Base material layer 22 Sealant layer 221 Barrier resin layer 222 First thermoplastic resin Layer 223 Second thermoplastic resin layer 224 Third thermoplastic resin layer 225 Fourth thermoplastic resin layer

Claims (7)

A laminate including at least a base material layer and a sealant layer in this order.
The base material layer contains virgin polyethylene terephthalate and recycled polyethylene terephthalate containing polyethylene terephthalate having ethylene glycol as a diol unit and terephthalic acid and isophthalic acid as a dicarboxylic acid unit.
The base material layer does not contain biomass polyester resin and does not contain.
In the biomass polyester resin, ethylene glycol derived from biomass is used as a diol unit, and a dicarboxylic acid derived from fossil fuel is used as a dicarboxylic acid unit.
The sealant layer is
Barrier resin layer and
A first thermoplastic resin layer provided on a surface of the barrier resin layer opposite to the base material layer,
It has a second thermoplastic resin layer provided on the surface of the barrier resin layer on the side of the base material layer.
The thickness of the base material layer is 5 μm or more and 25 μm or less.
The base material layer is a laminated body which is a biaxially stretched film . The sealant layer is located between the third thermoplastic resin layer located between the barrier resin layer and the first thermoplastic resin layer, and between the barrier resin layer and the second thermoplastic resin layer. The laminate according to claim 1 , further comprising a fourth thermoplastic resin layer. The laminate according to claim 1 or 2 , wherein the barrier resin layer contains a saponified product of an ethylene-vinyl acetate copolymer. The laminate according to claim 1 or 2 , wherein the barrier resin layer contains a polyamide. The laminate according to claim 1 or 2 , wherein the barrier resin layer contains polyvinyl alcohol. The invention according to any one of claims 1 to 5 , wherein the content of the isophthalic acid is 0.5 mol% or more and 5.0 mol% or less with respect to all the dicarboxylic acid units constituting the polyethylene terephthalate. Laminated body. The laminate according to any one of claims 1 to 6 , wherein the polyethylene terephthalate has an ultimate viscosity of 0.58 dl / g or more and 0.80 dl / g or less.

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