JP7290671B2 - pouch container - Google Patents

Description

TECHNICAL FIELD The present invention relates to packaging films and the like used for forming packaging materials such as pouch containers.

2. Description of the Related Art Conventionally, various articles such as foods, cosmetics, and medicines are packaged in various packaging materials and distributed. Among packaging materials, flexible packaging materials such as pouch containers and pillow packaging bags are formed from flexible packaging films. A laminate in which two or more base layers made of different materials are laminated is usually used as a packaging film that forms a flexible packaging material.

JP 2007-062786 A JP-A-2003-084670

Since the substrate layers of the packaging film are made of different materials, it is difficult to recycle them as raw materials unless each substrate layer is separated. Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-062786) discloses an easily peelable food packaging paper comprising a paper layer and a non-paper layer made of a resin film or a metal film adhered to the paper layer with wax. It is Such wrapping paper can be separated into a paper layer and a non-paper layer by pinching one of the paper layer and the non-paper layer and peeling off the other. However, the manual peeling and separation method requires a great deal of time and labor for recycling. Patent Document 2 discloses a plastic label in which a display printing ink layer is formed on a base film via an alkaline aqueous solution-soluble coating layer in order to separate the display printing ink layer from the base film. . However, Document 2 does not disclose separation of two substrate layers made of different materials.

An object of the present disclosure is to provide a packaging film in which at least two base layers made of different materials are laminated, in which each base layer can be easily separated and can be easily recycled, and a pouch container using this film. It is to be.

The packaging film of the present disclosure is a packaging film in which at least two base layers made of different materials are laminated, wherein two adjacent base layers are arranged between two adjacent base layers, and an intervening layer having solvent solubility, wherein the intervening layer is a layer that allows the two substrate layers to be separated by solvent immersion. According to this packaging film, the two substrate layers can be easily separated by immersion in an appropriate solvent, thereby providing an easily recyclable packaging film.

In a preferred packaging film of the present disclosure, the intermediate layer has at least one of water solubility and alkali solubility.

In preferred packaging films of the present disclosure, the intervening layer comprises an acrylic acid copolymer-based resin.

In preferred packaging films of the present disclosure, the intervening layer has an acid value of 40 mg-KOH/g or more and 150 mg-KOH/g or less.

A preferred packaging film of the present disclosure has a printed ink layer formed on at least one substrate layer.

In a preferable packaging film of the present disclosure, one base layer of the two adjacent base layers is a resin layer, and the other base layer is a metal thin film layer or a resin layer.

A pouch container of the present disclosure is formed using any one of the packaging films described above. According to this pouch container, since the two base material layers can be easily separated, it is possible to provide an easily recyclable pouch container.

By immersing the packaging film of the present disclosure in an appropriate solvent, the two substrate layers made of different materials can be easily separated. The packaging film of the present disclosure, which can be separated into different materials, and the pouch container using the same can be easily recycled.

FIG. 1 is a plan view with a part of the packaging film omitted. FIG. 2 is a cross-sectional view showing an example of the first laminated structure of the packaging film. FIG. 3 is a cross-sectional view showing another example of the first laminated structure of the packaging film. FIG. 4 is a cross-sectional view showing another example of the first laminated structure of the packaging film. FIG. 4 is a cross-sectional view showing another example of the first laminated structure of the packaging film. FIG. 6 is a cross-sectional view showing another example of the second laminated structure of the packaging film. FIG. 7 is a cross-sectional view showing another example of the second laminated structure of the packaging film. FIG. 8 is a cross-sectional view showing another example of the second laminated structure of the packaging film. FIG. 9 is a cross-sectional view showing another example of the second laminated structure of the packaging film. FIG. 10 is a cross-sectional view showing another example of the third laminated structure of the packaging film. FIG. 11 is a cross-sectional view showing another example of the third laminated structure of the packaging film. FIG. 12 is a cross-sectional view showing another example of the third laminated structure of the packaging film. FIG. 13 is a cross-sectional view showing another example of the third laminated structure of the packaging film. FIG. 14 is a cross-sectional view of a packaging film having two substrate layers with a pre-adhesive layer provided against an intervening layer. FIG. 15 is a cross-sectional view of a packaging film having three substrate layers with a pre-adhesive layer provided against an intervening layer. FIG. 16 is a cross-sectional view of a packaging film having four substrate layers with a pre-adhesive layer provided against an intervening layer. FIG. 17 is a perspective view showing an example of a pouch container formed using a packaging film. FIG. 18 is a perspective view showing an example of a pillow packaging bag formed using a packaging film.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In this specification, terms such as "first", "second", "third", etc. may be added at the beginning of terms, but the first etc. are added only for the purpose of distinguishing terms. There is no special meaning such as order or superiority. In this specification, the numerical range represented by "lower limit value X to upper limit value Y" means the lower limit value X or higher and the upper limit value Y or lower. When a plurality of numerical ranges are described separately, an arbitrary lower limit value and an arbitrary upper limit value can be selected, and "an arbitrary lower limit value to an arbitrary upper limit value" can be set. The dimensions, scales and shapes of layers and members shown in each drawing may differ from the actual ones. The front surface of the packaging film is the upper surface of the packaging film shown in each figure, and the back surface of the packaging film is the lower surface of the packaging film shown in each figure. The surface of each layer is the upper surface of each layer shown in each drawing, and the back surface of each layer is the lower surface of each layer shown in each drawing.

<Overview of packaging film>
The packaging film of the present disclosure is a packaging film in which at least two substrate layers made of different materials are laminated. Specifically, the packaging film of the present disclosure is a laminate comprising at least two adjacent base layers and an intervening layer arranged between the two base layers. The two substrate layers are made of dissimilar materials. The intervening layer is interposed between two base layers that are adjacent in the thickness direction. The intervening layer is a layer that is soluble in a solvent and that allows the two substrate layers to be separated by immersion in a solvent. In addition, solvent solubility refers to the property of dissolving in a solvent.

An intervening layer is thus a layer that allows two adjacent substrate layers to be separated when the packaging film is immersed in a suitable solvent. However, in a non-solvent immersed state (not immersed in a solvent), two adjacent base material layers are not separated. That is, the packaging film is a laminate in which each layer such as the base layer and the intervening layer maintains the adhesion state to such an extent that it cannot be easily peeled off by human power when it is not immersed in a solvent. Adhesion refers to a state in which two layers are bonded by physical or/and chemical force so that the layers cannot be easily separated by human power.

The packaging film may have at least two substrate layers adjacent to each other, and may have three or more substrate layers. In the case of having three or more base material layers, it is preferable that the three or more base material layers are provided with the intervening layer between two adjacent base material layers. In the packaging film, at least one base layer selected from a plurality of base layers (at least two base layers) may optionally have a printing ink layer formed thereon.

The printing ink layer consists of a solidified ink film formed by directly printing a known ink onto a substrate layer or the like by a known printing method. The printing ink layer is firmly adhered to the mating surface on which it is formed. The printing ink layer may be colored or non-colored (colorless and transparent). A colored printing ink layer may be opaque or colored and transparent. In the substrate layer on which the printing ink layer is formed, the intervening layer may be disposed between the printing ink layer and the substrate layer, and the intervening layer may be disposed between the substrate layer on which the printing ink layer is formed and the substrate adjacent thereto. It may be arranged between the layers.

Here, in this specification, transparent means colorless transparent or colored transparent. For "transparency", on the back side of the layer to be measured, place an arbitrary number (12 points in size) printed with black ink on a white paper at a distance of 1 cm from the back side, and place the above measurement. It refers to the state in which the number can be identified from the surface side through the target layer. "Opaque" means that the numbers placed on the back side cannot be seen from the front side under the same conditions as above (the numbers cannot be recognized).

As an index of transparency (colorless transparency or colored transparency), for example, total light transmittance can be used. Transparent (colorless transparent or colored transparent) means, for example, a total light transmittance of 70% or more, preferably 80% or more, and more preferably 90% or more. However, the total light transmittance refers to a value obtained by measuring a transparent object by a measuring method based on JIS K 7361:1997 (Plastics—Testing method for total light transmittance of transparent materials). If the substrate layer, intervening layer, or printing ink layer itself cannot be measured, a support film having a total light transmittance of 90% or more as measured by the JIS standard is used as the measurement object. and

The substrate layer, the intervening layer, and the printing ink layer are all layered, but the substrate layer differs from the intervening layer and the printing ink layer in that it can form a layer by itself. In other words, the substrate layer can maintain its layered state by itself, and the intervening layer and the printing ink layer form a layer while adhering to the substrate layer (they are supported by the substrate layer). However, it is very brittle by itself and cannot be broken by a slight force to maintain the layered state.

The packaging film is flexible. The packaging film as a whole may be transparent or opaque. Moreover, although the packaging film may have heat shrinkability, it is preferable to use a film that does not substantially have heat shrinkability. The heat shrinkability refers to the property of shrinking when heated to a desired temperature (for example, 70° C. to 90° C.).

Moreover, the planar view shape of a packaging film is a long belt shape, as shown in FIG. The long belt shape refers to a substantially rectangular shape in plan view whose length in the longitudinal direction is sufficiently longer than in the transverse direction, for example, the length in the longitudinal direction is 3 times or more, preferably 5 times the length in the transverse direction That's it. Specific dimensions of the elongated strip include, for example, a length of 100 mm to 3000 mm in the lateral direction and a length of 2 m to 500 m in the longitudinal direction. A long belt-like packaging film is usually wound into a roll shape for storage and transportation, and is cut into a desired shape for use when producing a packaging material. However, the packaging film of the present disclosure is not limited to a long belt shape, and may be formed in a sheet shape in plan view (not shown). Examples of the sheet shape include a substantially rectangular shape in a plan view, a substantially polygonal shape in a plan view such as a substantially triangular shape and a substantially hexagonal shape, and a substantially circular shape in a plan view.

<Example of laminated structure of packaging film>
The following are examples of some laminate structures of the packaging films of the present disclosure. 2 to 5 are cross-sectional views each showing an example of the first laminated structure of the packaging film. 2 to 5, the packaging film 1 is laminated with two base layers (referred to as a first base layer 21 and a second base layer 22 for convenience). The first base layer 21 and the second base layer 22 are base layers made of different materials.

Specifically, the packaging film 1 of FIG. 2 has a first base material layer 21, an intervening layer 3, and a second base material layer 22 laminated in this order from the surface side (upper side in the figure). there is In the packaging film 1 of FIG. 3, a first base material layer 21, a colored printing ink layer 41, an intervening layer 3, and a second base material layer 22 are laminated in this order from the surface side. . In the packaging film 1 of FIG. 4, a first base material layer 21, an intervening layer 3, a colored printing ink layer 41, and a second base material layer 22 are laminated in this order from the surface side. . In the packaging film 1 of FIG. 5, a colorless and transparent printed ink layer 42, a first base material layer 21, an intervening layer 3, and a second base material layer 22 are laminated in this order from the surface side. .

The packaging film 1 in which the colored printing ink layer 41 is formed between the first base layer 21 and the second base layer 22 can have, for example, the following configuration:
(A) Each layer (for example, the The first substrate layer 21, the first substrate layer 21 and the intervening layer 3) in FIG. 4 are transparent, and each layer arranged on the back side of the colored printing ink layer 41 is transparent or opaque. is;
(B) In order to make the color of the colored printed ink layer 41 visible from the back side of the packaging film 1, each layer arranged on the back side of the colored printed ink layer 41 (for example, The second base material layer 22 and the intervening layer 3 (the second base material layer 22 in FIG. 4) are transparent, and each layer arranged on the surface side of the colored printing ink layer 41 is transparent or opaque. is.

The colored printing ink layer 41 is not limited to being formed between the first base material layer 21 and the second base material layer 22, and may be formed on the surface of the first base material layer 21. (In this case, for example, even if the first base material layer 21 is opaque, the color can be visually recognized from the surface side), or it may be formed on the back surface of the second base material layer 22 (in this case , and even if the second base material layer 22 or the like is opaque, the color can be visually recognized from the back side). Also, the colored printing ink layer 41 may be formed between the substrate layers and on the surface of the first substrate layer 21 and/or the back surface of the second substrate layer 22 . In addition, the colorless and transparent printing ink layer 42 is not limited to being formed on the surface of the first substrate layer 21, and may be formed between the first substrate layer 21 and the second substrate layer 22 or/and It may be formed on the back surface of the second base material layer 22 .

6 to 9 are cross-sectional views each showing an example of the second laminated structure of the packaging film. 6 to 9, the packaging film 1 is laminated with three base layers (referred to as a first base layer 21, a second base layer 22 and a third base layer 23 for convenience). In these packaging films 1, there are two sets of two adjacent base layers, and at least one set of two adjacent base layers are base layers made of different materials, Two adjacent substrate layers in a set are substrate layers made of different materials from each other.

Specifically, the packaging film 1 of FIG. , and are stacked in this order. In this example, the first base material layer 21 and the third base material layer 23 are in a relationship of two adjacent base material layers, and the third base material layer 23 and the second base material layer 22 are adjacent to each other. There is a relationship between two base material layers. For example, the first base material layer 21, the second base material layer 22, and the third base material layer 23 are all preferably different materials. The packaging film 1 in FIG. 7 includes, in order from the surface side, the first base material layer 21, the colored printing ink layer 41, the intervening layer 3, the third base material layer 23, the intervening layer 3, and the second and the base layer 22 are laminated in this order. The packaging film 1 in FIG. 8 includes, in order from the surface side, the first base layer 21, the intervening layer 3, the colored printing ink layer 41, the third base layer 23, the intervening layer 3, and the second and the base layer 22 are laminated in this order. The packaging film 1 in FIG. 9 includes, in order from the surface side, a colorless and transparent printed ink layer 42, a first base material layer 21, an intervening layer 3, a third base material layer 23, an intervening layer 3, and a second and the base layer 22 are laminated in this order.

The packaging film 1 in which the colored printing ink layer 41 is formed between the first base layer 21 and the third base layer 23 can have a configuration such as (A) or (B) below, for example. :
(A) Each layer arranged on the surface side of the colored printing ink layer 41 is transparent so that the color of the colored printing ink layer 41 can be seen from the surface side of the packaging film 1; And each layer arranged on the back side of the colored printing ink layer 41 is transparent or opaque;
(B) In order to make the color of the colored printing ink layer 41 visible from the back side of the packaging film 1, each layer arranged on the back side of the colored printing ink layer 41 should be transparent. Each layer used and arranged on the surface side of the colored printing ink layer 41 is transparent or opaque.

Note that the colored printing ink layer 41 is not limited to being formed between the first base layer 21 and the third base layer 23 , and is formed between the third base layer 23 and the second base layer 22 . may be formed in Also in the packaging film 1 having three base layers, the colored printing ink layer 41 is formed on the surface of the first base layer 21 in the same manner as in the packaging film 1 having two base layers. Alternatively, it may be formed on the back surface of the second substrate layer 22, or between the layers of the substrate layers and on the surface of the first substrate layer 21 and/or the second substrate layer 22 may be formed on the back surface of the In addition, the colorless and transparent printing ink layer 42 is not limited to being formed on the surface of the first base material layer 21, but is formed between the base material layers and/or on the back surface of the second base material layer 22. may be

10 to 13 are cross-sectional views each showing an example of the third laminated structure of the packaging film. 10 to 13, the packaging film 1 has four base layers (for convenience, referred to as a first base layer 21, a second base layer 22, a third base layer 23 and a fourth base layer 24). It is In the four laminated base material layers, there are three sets of two adjacent base material layers, but at least one set of adjacent base material layers is a base layer made of a different material from each other, preferably The three sets of adjacent base layers are base layers made of different materials from each other.

Specifically, the packaging film 1 of FIG. , the intervening layer 3 and the second base material layer 22 are laminated in this order. In this example, the first base material layer 21 and the third base material layer 23 are in a relationship of two adjacent base material layers, and the third base material layer 23 and the fourth base material layer 24 are adjacent to each other. There is a relationship of two base material layers, and the fourth base material layer 24 and the second base material layer 22 have a relationship of two adjacent base material layers. For example, the first base layer 21, the second base layer 22, the third base layer 23, and the fourth base layer 24 are all preferably different materials. The packaging film 1 of FIG. 11 includes, in order from the surface side, the first base layer 21, the colored printing ink layer 41, the intervening layer 3, the third base layer 23, the intervening layer 3, and the fourth layer. The base material layer 24, the intervening layer 3, and the second base material layer 22 are laminated in this order. The packaging film 1 of FIG. 12 includes, in order from the surface side, the first base layer 21, the intervening layer 3, the colored printing ink layer 41, the third base layer 23, the intervening layer 3, and the fourth layer. The base material layer 24, the intervening layer 3, and the second base material layer 22 are laminated in this order. The packaging film 1 of FIG. 13 includes, in order from the surface side, a colorless and transparent printed ink layer 42, a first base layer 21, an intervening layer 3, a third base layer 23, an intervening layer 3, and a fourth The base material layer 24, the intervening layer 3, and the second base material layer 22 are laminated in this order.

The packaging film 1 in which the colored printing ink layer 41 is formed between the first base layer 21 and the third base layer 23 can have a configuration such as (A) or (B) below, for example. :
(A) Each layer arranged on the surface side of the colored printing ink layer 41 is transparent so that the color of the colored printing ink layer 41 can be seen from the surface side of the packaging film 1; And each layer arranged on the back side of the colored printing ink layer 41 is transparent or opaque;
(B) Each layer arranged on the back side of the colored printing ink layer 41 is transparent so that the color of the colored printing ink layer 41 can be seen from the back side of the packaging film 1; Moreover, each layer arranged on the surface side of the colored printing ink layer 41 is transparent or opaque.

Note that the colored printing ink layer 41 is not limited to being formed between the first base layer 21 and the third base layer 23, and is formed between the third base layer 23 and the fourth base layer 24. and/or between the fourth substrate layer 24 and the second substrate layer 22 . Also in the packaging film 1 having four base layers, the colored printing ink layer 41 is formed on the surface of the first base layer 21 in the same manner as in the packaging film 1 having two base layers. Alternatively, it may be formed on the back surface of the second substrate layer 22, or between the layers of the substrate layers and on the surface of the first substrate layer 21 and/or the second substrate layer 22 may be formed on the back surface of the In addition, the colorless and transparent printing ink layer 42 is not limited to being formed on the surface of the first base material layer 21, but is formed between the base material layers and/or on the back surface of the second base material layer 22. may be

14 to 16 are cross-sectional views showing an example of a configuration in which a preliminary adhesive layer that complements the intervening layer is provided between adjacent base layers of the packaging film. Specifically, FIG. 14 is a cross-sectional view of a packaging film having two substrate layers with a pre-adhesive layer provided in contact with an intervening layer. FIG. 15 is a cross-sectional view of a packaging film having three substrate layers with a pre-adhesive layer provided against an intervening layer. FIG. 16 is a cross-sectional view of a packaging film having four substrate layers with a pre-adhesive layer provided against an intervening layer.

When the intervening layer does not adhere or adheres poorly to the base layer or to the printing ink layer formed on the base layer, between the intervening layer and the base layer and/or the intervening A preliminary adhesive layer 5 is optionally provided between the layer and the printing ink layer formed on the substrate layer. 14 to 16, the preliminary adhesive layer 5 is provided between the printing ink layer 41 formed on the first base material layer 21 and the intervening layer 3, but is not limited to this. A preliminary adhesive layer 5 may be provided between appropriate layers. Further, the preliminary adhesive layer 5 is not limited to one layer, and may be provided between several layers.

Although not shown, the preliminary adhesive layer 5 may be arranged on the packaging film 1 in which five or more base layers are laminated. As for packaging films having five or more base layers, two base layers in which two adjacent base layers are made of different materials and an intervening layer is provided between the two base layers are used in the same manner as described above. It is only necessary to have at least a material layer.

<Intermediate layer>
Intervening layers are solvent soluble and are disposed between adjacent substrate layers. For example, an intervening layer is between two adjacent substrate layers and directly adheres to the back surface of one substrate layer and the front surface of the other substrate layer to bind both substrate layers. This aspect is illustrated in FIGS. 2, 5, 6 and 9, for example. Further, for example, the intervening layer is located between two adjacent base layers, and is the back surface (or surface) of the printed ink layer of one base layer on which the printed ink layer is formed and the surface of the other base layer. It adheres directly to the front (or back) and binds both substrate layers via one printed ink layer. This aspect is illustrated in FIGS. 3, 4, 7 and 8, for example. Further, for example, the intervening layer is between two adjacent base layers, and the back surface (or surface) of the printed ink layer of one of the base layers on which the printed ink layer is formed and the printed ink layer are formed. The surface (or the back surface) of the printed ink layer of the other base layer is directly adhered to bind the two base layers via the one and the other printed ink layers.

In addition, when it is difficult for the intervening layer to adhere directly to the surface or back surface of the base material layer or the printing ink layer due to the relationship between the materials of the base material layer or the printing ink layer, etc., the preliminary adhesive layer is used. Provided as appropriate. As mentioned above, the preliminary adhesive layer is provided between the intermediate layer and the substrate layer or/and between the intermediate layer and the printing ink layer. In this case, the pre-adhesive layer and the intervening layer cooperate to bind the two adjacent substrate layers.

The solvent-soluble intervening layer has, for example, at least one property selected from water solubility, alkali solubility, organic solvent solubility, etc., and preferably has at least one of water solubility and alkali solubility. The solvent-soluble intervening layer contains a solvent-soluble polymer as a main component. The intervening layer may contain components other than the solvent-soluble polymer, which is the main component, and examples of such components include known additives and residual solvents.

Here, in this specification, the main component of a certain layer refers to the component (weight ratio) that is the largest among the components contained in the layer. For example, the main component is contained in an amount of 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more, when the entire layer is taken as 100% by weight.

Since the intervening layer contains a solvent-soluble polymer as a main component, when the packaging film is immersed in a solvent, the solvent-soluble polymer in the intervening layer is eluted from between the substrate layers into the solvent. The intervening layer thereby diminishes or eliminates the ability to bind between the layers or cooperate with the preliminary adhesive layer to bind between the substrate layers. Therefore, two substrates adjacent to each other with an intervening layer interposed therebetween are easily separated.

A solvent-soluble polymer is a polymer that exhibits solubility in a given solvent. Solvent-soluble polymers include water-soluble polymers, alkali-soluble polymers, organic solvent-soluble polymers, etc. Preferably, at least one of water-soluble polymers and alkali-soluble polymers is used. The intervening layer containing a water-soluble polymer as a main component has water solubility, and the intervening layer containing an alkali-soluble polymer as a main component has alkali solubility.

A water-soluble polymer is a polymer that exhibits solubility in water or an aqueous solvent at normal temperature and pressure. is a polymer of 5 (g/100 g) or more. Moreover, the water-soluble polymer preferably has improved solubility in water heated to an appropriate temperature. The heating temperature may be 50°C to 100°C.

The water-soluble polymer is not particularly limited, and examples thereof include synthetic resins and natural polymers. Examples of synthetic resins include polyvinyl alcohol-based resins such as polyvinyl alcohol and modified polyvinyl alcohol, polyvinyl acetate-based resins, cellulose-based resins, acrylic-based resins, polyacrylamide-based resins, polyethylene oxide-based resins, polyurethane-based resins, amino-based resins, etc. Examples of natural polymers include polysaccharides such as starch and polypeptides, glue, casein, natural rubber, and the like. These may be used alone or in combination of two or more.

An aqueous solvent is a mixed solvent containing water and a hydrophilic solvent. A hydrophilic solvent is a solvent that can be uniformly dissolved in water. Examples of hydrophilic solvents include alcohols such as methanol, glycols such as ethylene glycol, cellosolves such as methyl cellosolve, and esters such as ethyl acetate.

The alkali-soluble polymer is a polymer that exhibits solubility in an alkaline aqueous solution under normal temperature and normal pressure. /100 g) or more, preferably a polymer with a solubility of 5 (g/100 g) or more. Further, the alkali-soluble polymer preferably has improved solubility in the alkaline aqueous solution heated to an appropriate temperature. The heating temperature may be 50°C to 100°C.

The alkali-soluble polymer is not particularly limited, and examples thereof include a copolymer of one or more unsaturated carboxylic acids and one or more compounds having a polymerizable unsaturated group. . Unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid and the like. Compounds having a polymerizable unsaturated group include alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, and propyl methacrylate. , methacrylic acid alkyl esters such as butyl methacrylate; hydroxyl group-containing polymerizable unsaturated compounds such as hydroxyethyl acrylate and hydroxyethyl methacrylate; cyano group-containing polymerizable unsaturated compounds such as acrylonitrile and methacrylonitrile; acrylamide, methacrylamide, Amide group-containing polymerizable unsaturated compounds such as N-alkoxyacrylamide, N-alkoxymethacrylamide, N-methylol acrylamide, and N-methylol methacrylamide; Styrenic compounds such as styrene, vinyltoluene, α-methylstyrene, and divinylbenzene; olefins such as ethylene; allyl group-containing compounds such as diallyl phthalate, allyl glycidyl ether and triallyl isocyanurate; vinyl esters such as vinyl acetate; and N-vinylpyrrolidone.

In particular, styrene-maleic anhydride resin having an acid value of 50 to 300 (mg-KOH/g), rosin-maleic acid resin having an acid value of 50 to 300 (mg-KOH/g), 50 to 300 An alkali-soluble polymer containing an acrylic acid copolymer resin having an acid value of (mg-KOH/g) as a main component is preferred.

A known styrene-maleic anhydride resin can be used as the styrene-maleic anhydride resin. For example, suitable styrene-maleic anhydride-based resins include known styrene-maleic anhydride copolymers, which are copolymers of styrene and maleic anhydride, and modified styrene-maleic anhydride copolymers (such as , partially esterified products, etc.). In the styrene-maleic anhydride copolymer, as styrene, styrene-based compounds such as α-methylstyrene can be used in addition to styrene.

A known rosin-maleic acid resin can be used as the rosin-maleic acid resin. For example, a suitable rosin-maleic acid-based resin is an esterified product obtained by condensing an addition reaction product of rosin and maleic anhydride (for example, an adduct of tribasic acid) with a polyhydric alcohol (glycerin, etc.). mentioned.

The acrylic acid copolymer-based resin is a resin having acrylic acid and/or methacrylic acid as a main repeating unit, and a copolymerizable monomer copolymerizable with the acrylic acid and/or methacrylic acid. The acrylic acid copolymer-based resin preferably has a total proportion of acrylic acid and/or methacrylic acid and copolymerizable monomers in the resin of 60 mol % or more.

Examples of copolymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)acrylic acid alkyl esters such as t-butyl (meth)acrylate [preferably lower alkyl esters of (meth)acrylic acid]; hydroxyl group-containing (meth)acrylates such as hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; Glycidyl group-containing (meth)acrylates such as acrylates; (meth)acrylamides such as N,N'-dimethyl (meth)acrylamide and N,N'-diethyl (meth)acrylamide; amino groups such as dimethylaminoethyl (meth)acrylate Containing (meth)acrylate; styrenes such as styrene, vinyl toluene and α-methylstyrene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl halides such as vinyl chloride; vinyl ethers such as methyl vinyl ether; Carboxyl group-containing vinyls such as maleic anhydride [excluding (meth)acrylic acid]; cyano group-containing vinyls such as acrylonitrile and methacrylonitrile; olefins and dienes such as ethylene and propylene; Comonomers may be used alone or in combination of two or more.

Also, the intermediate layer preferably has an acid value of 40 to 150 (mg-KOH/g). For example, when the intervening layer is mainly composed of an acrylic acid copolymer resin and the acrylic acid copolymer resin is a mixed resin of two kinds of acrylic acid copolymer resins, the acid value of the intervening layer is It becomes a value different from each acid value of acrylic acid copolymer system resin. Moreover, even when the intervening layer contains a resin having an acid value in addition to the resin that is the main component, the acid value of the intervening layer is different from the acid value of the resin that is the main component. The acid value of the intermediate layer varies depending on the acid value of each resin contained and the content ratio of each. The acid value of the intervening layer can be confirmed, for example, by measuring the acid value of the resin composition forming the intervening layer.

In addition, the intervening layer preferably further contains a vinyl chloride-vinyl acetate copolymer in addition to the above-mentioned main component resin. In this case, the adhesion of the intervening layer to other layers can be improved, and the design of the packaging film can be improved.

The content of the vinyl chloride-vinyl acetate copolymer in the intermediate layer is preferably 1 to 10% by weight, more preferably 2 to 5% by weight, when the entire intermediate layer is 100% by weight. If the weight % is less than 1, further improvement of the adhesion tends to be insufficient, and if it exceeds 10, the viscosity of the intervening layer becomes too high and handling tends to be difficult. The vinyl chloride-vinyl acetate copolymer preferably has a Mn (number average molecular weight) of 10,000 to 40,000, more preferably 15,000 to 35,000. In this case, the improvement in adhesion becomes remarkable.

The intervening layer of the present disclosure is preferably a layer formed from a resin composition having an acrylic acid copolymer-based resin as a main component and an apparent acid value of 40 to 150 (mg-KOH/g). . Further, it preferably contains a vinyl chloride-vinyl acetate copolymer. At this time, the acrylic acid copolymer-based resin may be a mixed resin of two or more acrylic acid copolymer-based resins.

Further, as the alkali-soluble polymer, those described in Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2003-084670) may be used. As an intervening layer containing an alkali-soluble polymer that can be used in the present disclosure, the alkali-soluble coat layer described in Patent Document 2 is described in this specification, and due to space limitations, the description of Patent Document 2 is used in this specification. omitted. However, at least the descriptions of [0011] to [0032] of Patent Document 2 can be incorporated in this specification as they are. The alkali-soluble coating layer described in Patent Document 2 is preferably used as an intervening layer between the printing ink layer and the substrate layer of the present disclosure.

The thickness of the intervening layer is not particularly limited, and is, for example, 0.5 μm to 20 μm, preferably 1 μm to 15 μm.

<Preliminary adhesive layer>
A preliminary adhesive layer is optionally provided between the intervening layer and the substrate layer and/or between the intervening layer and the printing ink layer. The preliminary adhesive layer is not particularly limited as long as it can adhere two layers between the layers in which it is interposed, and known adhesives can be used. For example, as the preliminary adhesive layer, a so-called dry laminate adhesive such as a solvent volatile adhesive, a non-solvent adhesive, an anchor coating agent, or the like can be used.

<Base material layer>
Examples of the substrate layer include a resin layer, a metal thin film layer, a nonwoven fabric layer, and a paper layer. Examples of the resin layer include those containing a known resin as a main component. Examples of the resin include polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polylactic acid; polyolefin resins such as polyethylene and polypropylene; polyamide resins such as 6-nylon and 66-nylon; polystyrene resins; polycarbonate resins; nitrile resins such as polyacrylonitrile; imide resins such as polyimide; vinyl chloride resins such as polyvinyl chloride and polyvinylidene chloride; be done. The thickness of the resin layer is not particularly limited, and is, for example, 10 μm to 200 μm, preferably 10 μm to 100 μm. The resin layer is usually a non-foamed layer, but may be foamed.

Examples of metal thin film layers include aluminum foil and copper foil. The thickness of the metal thin film layer is not particularly limited, and is, for example, 5 μm to 30 μm. Examples of the nonwoven fabric layer include a nonwoven fabric formed by fabricating fibers into a sheet by a bonding method, a needle punching method, a spunbonding method, a melt blowing method, or the like. Examples of the fibers include polyester fibers; polyolefin fibers such as polypropylene and polyethylene; rayon fibers; polyamide fibers such as nylon; and natural fibers. The basis weight of the nonwoven fabric is not particularly limited, and is, for example, 10 to 100 g/m ² . Examples of the paper layer include plain paper and fine paper.

The polyvinylidene chloride resin layer and the metal thin film layer have gas barrier properties. By using such a substrate layer having gas barrier properties, gas barrier properties can be imparted to the packaging film. In addition, the low-density polyethylene layer, the ethylene-propylene copolymer layer, the ethylene-olefin copolymer layer, etc. have sealant properties (thermal adhesion properties). Sealant properties can be imparted to the packaging film by using such a base layer having sealant properties (for example, a base layer constituting the backmost surface of the laminate).

Furthermore, a polyester resin layer such as polyethylene terephthalate and a polyamide resin layer such as nylon are superior in heat resistance in comparison with sealant properties. Therefore, heat resistance can be imparted to the packaging film by using such a base layer having heat resistance (for example, a base layer forming the outermost surface of the laminate). In addition, the foamed resin layer, non-woven fabric layer, etc. have heat insulating properties. By using such a heat-insulating substrate layer, heat-insulating properties can be imparted to the packaging film.

As described above, the two adjacent substrate layers provided with the intervening layer are composed of dissimilar materials. Here, the two base layers made of different materials refer to those composed of different materials as main components, and the two base layers made of the same material are composed of the same material as the main component. say something

For example, substrate layers made of different materials include a resin layer and a metal thin film layer (resin and metal are different materials), a resin layer and a paper layer (resin and pulp are different materials), a metal thin film layer and a paper layer (metal and Pulp is a different material).

Moreover, in the resin layer, resin layers containing different resins as main components are in a relationship of substrate layers made of different materials. Similarly, in the metal thin film layer, the metal thin film layers mainly composed of different metals are in the relationship of base layers made of different materials, and in the nonwoven fabric layer, the nonwoven fabric layers mainly composed of different fibers are different materials It has a relationship of a base material layer.

For example, a resin layer containing polyethylene terephthalate as a main component and a resin layer containing polyethylene as a main component have a relationship of two substrate layers containing different resins as main components and made of different materials. In addition, the metal thin film layer (aluminum foil) containing aluminum as the main component and the metal thin film layer (copper foil) containing copper as the main component have different metals as the main component and are made of different materials. It is in. Furthermore, the non-woven fabric layer mainly composed of rayon fiber and the non-woven fabric layer mainly composed of nylon have a relationship of two base material layers composed of different materials with different fibers as the main component.

On the other hand, the resin layer mainly composed of polyethylene terephthalate and the non-woven fabric mainly composed of polyethylene terephthalate fibers are two substrate layers composed of the same resin as the main component and of the same material.

In the packaging film 1 having two base layers shown in FIGS. 2 to 5, for example, an arbitrary resin layer is used as the first base layer 21, which is the base layer on the front side, and the back side A resin layer made of a different resin material is used as the second base material layer 22, which is the base material layer of the second base material layer 22, and a solvent-soluble intervening layer 3 is provided therebetween.

In the packaging film 1 having three base layers shown in FIGS. 6 to 9, for example, an arbitrary resin layer is used as the first base layer 21, which is the front side base layer, A resin layer made of a different resin material is used as the third base layer 23, which is a base layer, and a resin made of a different resin material is used as the second base layer 22, which is the base layer on the back side. Intermediate layers 3 having solvent solubility are provided between the first base layer 21 and the third base layer 23 and between the third base layer 23 and the second base layer 22, respectively. It is

Moreover, a metal thin film layer, a nonwoven fabric layer, or a paper layer may be used as the third base material layer 23 . Furthermore, base layers made of the same material may be used as the first base layer 21 and the third base layer 23, or base layers made of the same material may be used as the third base layer 23 and the second base layer 22. A material layer may be used. Thus, in the packaging film 1 including two adjacent base layers made of the same material, even if the solvent-soluble intervening layer 3 is provided between the two base layers made of the same material. Alternatively, no such intervening layer may be provided.

When the packaging film 1 having three base layers shown in FIGS. 6 to 9 is used as a pouch film for forming a pouch container, for example, it can be configured as follows.
A first base material layer 21 having heat resistance such as a polyester resin layer or a polyamide resin layer such as nylon;
a third base material layer 23 having gas barrier properties such as a polyvinylidene chloride resin layer or a metal thin film layer;
A second base material layer 22 having sealant properties such as a low-density polyethylene layer or an ethylene-propylene copolymer layer.

In the packaging film 1 having four base layers shown in FIGS. A metal thin film layer is used as the third base layer 23 which is the material layer, an arbitrary resin layer is used as the fourth base layer 24, and the second base layer 22 which is the base layer on the back side is used. , a resin layer made of a different resin material is used between the first base layer 21 and the third base layer 23, between the third base layer 23 and the fourth base layer 24, and between the fourth base layer 23 and the fourth base layer 24. Between the base material layer 24 and the second base material layer 22, intervening layers 3 each having solvent solubility are provided.

A resin layer, a nonwoven fabric layer, or a paper layer may be used as the third base material layer 23, or a metal thin film layer, a nonwoven fabric layer, or a paper layer may be used as the fourth base material layer 24. good too. Further, base layers made of the same material may be used as the first base layer 21 and the third base layer 23, or base layers made of the same material may be used as the third base layer 23 and the fourth base layer 24. Alternatively, base layers made of the same material as the fourth base layer 24 and the second base layer 22 may be used. Thus, in the packaging film 1 including two adjacent base layers made of the same material, even if the solvent-soluble intervening layer 3 is provided between the two base layers made of the same material. Alternatively, no such intervening layer may be provided.

When the packaging film 1 having four base layers shown in FIGS. 10 to 13 is used as a pouch film for forming a pouch container, for example, it can be configured as follows.
A first base material layer 21 having heat resistance such as a polyester resin layer or a polyamide resin layer such as nylon;
a third base material layer 23 having gas barrier properties such as a polyvinylidene chloride resin layer or a metal thin film layer;
A fourth base material layer 24 having heat resistance such as a polyester resin layer or a polyamide resin layer such as nylon;
A second base material layer 22 having sealant properties such as a low-density polyethylene layer or an ethylene-propylene copolymer layer.

<Manufacturing method of packaging film>
The packaging film is obtained by laminating each base material layer with an intervening layer interposed therebetween. For example, a solution obtained by dissolving a solvent-soluble polymer in an appropriate solvent is applied to the bonding surface of one or both of two adjacent base material layers to form an uncured intervening layer, and then the solvent is removed by drying or the like. do. As a result, the solvent-soluble intervening layer adheres the two adjacent base material layers.

The method of applying the solution containing the solvent-soluble polymer is not particularly limited, and includes conventionally known printing methods, coater methods using an appropriate coater, and the like. The concentration of the solution containing the solvent-soluble polymer is not particularly limited, and may be adjusted so as to have an appropriate viscosity according to the coating method.

<Application of packaging film>
The packaging film of the present disclosure can usually be used as a known packaging material (including tack labels and the like), and is used after being processed into a flexible packaging material, for example. Flexible packaging materials are soft packaging materials for wrapping various articles. The flexible packaging material formed using the packaging film of the present disclosure preferably wraps articles in a hermetically sealed manner, and typical examples of such flexible packaging materials include pouch containers, pillow packaging bags, and the like. .

FIG. 17 is a perspective view showing an example of a pouch container formed using a packaging film. FIG. 18 is a perspective view showing an example of a pillow packaging bag formed using a packaging film. The packaging film forming the pouch container A1, the pillow packaging bag A2, etc. uses a base layer having sealant properties as the base layer on the outermost surface (the surface located on the inner space side of the container and the packaging bag). is preferred.

The packaging film of the present disclosure is provided with an intervening layer between two substrate layers made of dissimilar materials that is solvent-soluble and allows the two substrate layers to be separated by solvent immersion. By immersing such a packaging film in a suitable solvent, the intervening layer dissolves, making it possible to easily separate the substrate layers made of different materials.

For example, when a water-soluble intervening layer is used in the packaging film, the packaging film is immersed in water or a water-based solvent, so that water penetrates into the intervening layer from the end face of the intervening layer, Adhesion of the intervening layer gradually decreases or disappears. This makes it possible to easily separate the two substrate layers made of different materials. For example, when an intervening layer having alkali solubility is used in the packaging film, by immersing the packaging film in an alkaline water solution, alkali penetrates into the intervening layer from the end surface of the intervening layer, and the intervening layer Adhesion diminishes or disappears. This makes it possible to easily separate the two substrate layers made of different materials. Therefore, the packaging film can be easily recycled by separating the packaging film for each material.

In another aspect, the present disclosure provides a packaging film provided with a solvent-soluble intervening layer between two adjacent substrate layers made of different materials by immersing each substrate layer in an appropriate solvent. It provides a method of separating into As will be apparent from the examples below, the intervening layer can separate the two substrate layers at the latest after 24 hours of solvent immersion.

By immersing the packaging film processed into a flexible packaging material such as the pouch container in an appropriate solvent in the form of the flexible packaging material, the two adjacent base layers can be separated via the intervening layer. Preferably, the flexible packaging material is arbitrarily cut into small pieces so that separation can be made more quickly. Regarding the degree of fragmentation, the smaller the area, the shorter the time required for separation. The packaging film of the present disclosure is provided with an intervening layer that, when cut into small pieces of, for example, 60 square cm, allows the two substrate layers to separate without particular load at least 24 hours after immersion in the solvent. There is.

Examples and comparative examples are described below to further describe the present disclosure. However, the present disclosure is not limited to the following examples.

[Example 1]
On the back of a biaxially oriented polyethylene terephthalate film with a thickness of 12 μm (trade name “E5100” manufactured by Toyobo Co., Ltd.), an aqueous solution of a water-soluble polymer (trade name “Nichigo G Polymer” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) (polymer concentration 10 weight %) was applied solidly to a thickness of about 3 μm using a gravure printing method to form a first intervening layer. After that, an aluminum foil having a thickness of 7 μm (trade name “general foil” manufactured by Toyo Aluminum Co., Ltd.) was laminated and adhered to the first intervening layer. Further, the aqueous solution of the water-soluble polymer was applied solidly on the back surface of the aluminum foil with a thickness of about 3 μm using the gravure printing method to form a second intervening layer. Thereafter, a low-density polyethylene film (trade name “L4102” manufactured by Toyobo Co., Ltd.) having a thickness of 80 μm was laminated and adhered to the second intermediate layer to prepare a laminate. After that, the entire laminate was dried with hot air at about 80°C. As a result, a laminated structure of a polyethylene terephthalate resin layer/a water-soluble first intervening layer having a thickness of about 3 μm/an aluminum thin film layer/a water-soluble second intervening layer having a thickness of about 3 μm/polyethylene resin layer is formed in this order from the surface side. A packaging film having

The packaging film of Example 1 was cut into strips with a width of 15 mm to obtain test pieces, and the 180° peel strength of the test pieces was measured. As a result, the 180° peel strength of the test piece was 4.0 N/15 mm, indicating that it was adhered with sufficient strength. The peel strength was measured using a tensile tester (trade name “Autograph” manufactured by Shimadzu Corporation) at a peel speed of 200 mm/min. In the above measurement, the peel strength when peeling the polyethylene terephthalate resin layer from the laminate and the peel strength when peeling the polyethylene resin layer from the laminate were measured. , listed one value. The same applies to the following.

Next, the packaging film of Example 1 was cut to length x width = 60 mm x 100 mm to prepare several identical sample pieces, which were immersed in room temperature tap water and left at room temperature (23°C). . After immersion, one sample piece was taken out every 20 minutes, and the peelability between each layer was confirmed.

As a result, after 6 hours, the aluminum thin film layer and the polyethylene resin layer peeled off without any resistance. Moreover, when 24 hours had passed, the polyethylene terephthalate resin layer and the aluminum thin film layer peeled off without any resistance.

[Example 2]
15 parts by weight of styrene-maleic anhydride resin (acid value: 270 mg-KOH/g) (trade name "SMA17352P" manufactured by Kawase Chemical Co., Ltd.), 4 parts by weight of acrylic resin (acid value: 4 mg-KOH / g, glass transition temperature: 47 ° C.) (trade name “UH2011” manufactured by Toagosei Co., Ltd.), and 1 part by weight of a cellulose derivative (trade name “CAB-381-0. 5”) was dissolved in a mixed solvent of 50 parts by weight of ethyl acetate and 30 parts by weight of isopropyl alcohol to obtain a uniform resin liquid (coating agent). Among the coating agents, the styrene-maleic anhydride resin is an alkali-soluble polymer. The apparent acid value of this coating agent is 203 mg-KOH/g.

After applying this coating agent in a solid manner to a thickness of about 1 μm on the back surface of a nylon film with a thickness of 15 μm (trade name “Emblem ON” manufactured by Unitika Ltd.) using a gravure printing method, the coating agent is coated with hot air at about 80°C. to form an intervening layer. Next, on the back surface of this intervening layer, white ink (trade name “Rio Alpha S” manufactured by Toyo Ink Co., Ltd.) was solidly printed with a thickness of about 1 μm using a gravure printing method. Thereafter, a dry laminate adhesive (trade name “LX500” manufactured by DIC Graphics Co., Ltd.) was applied solidly to the back surface of the printing ink layer using a gravure printing method to a thickness of about 3 μm, and then the solvent component was removed. The adhesive was volatilized to a dry state in which the adhesive could be adhered, and a polyethylene film having a thickness of 70 μm (trade name “SE620” manufactured by Tamapoly Co., Ltd.) was laminated and adhered. As a result, a packaging film consisting of nylon resin layer/alkali-soluble intervening layer having a thickness of about 1 μm/printing ink layer/adhesive layer/polyethylene resin layer in order from the surface side was produced.

Using the packaging film of Example 2, the peel strength was measured in the same manner as in Example 1. The 180° peel strength was 4.0 N/15 mm, indicating that the film was adhered with sufficient strength.

Next, the packaging film of Example 2 was cut into length x width = 60 mm x 100 mm to prepare one sample piece. This sample piece was immersed in a 1.5% by weight sodium hydroxide aqueous solution at 85° C., and simple stirring was continued while maintaining the temperature, and peeling of the nylon layer and the polyethylene layer was observed every 20 minutes.

As a result, the nylon layer and the polyethylene layer were separated after 24 hours from the start of immersion.

[Example 3]
Acrylic acid copolymer resin (acid value: 50 mg-KOH/g) (trade name “Dianal LR-1941” manufactured by Mitsubishi Rayon Co., Ltd.) and acrylic acid copolymer resin (acid value: 85 mg-KOH/g ) (trade name “JONCRYL JDX3000” manufactured by BASF) to prepare an acrylic acid copolymer resin having an acid value of 63 (mg-KOH/g).

Next, 33 parts by weight of the above acrylic acid copolymer resin (acid value: 63 mg-KOH/g), and 3 parts by weight of a cellulose derivative (trade name "RS-1 sec" manufactured by Corea CNC, solid content 70 parts by weight) was dissolved in a mixed solvent of 44 parts by weight of ethyl acetate and 20 parts by weight of isopropyl alcohol to obtain a uniform resin liquid (coating agent). Among the coating agents, the acrylic acid copolymer-based resin is an alkali-soluble polymer. The apparent acid value of this coating agent is 57 mg-KOH/g.

Instead of the water-soluble polymer of Example 1, the coating agent prepared as described above was used, and instead of the aluminum foil, a nylon film having a thickness of 15 μm (trade name “EMBLEM ON” manufactured by Unitika Ltd.) was used. A packaging film was produced in the same manner as in Example 1 except for the above. The prepared packaging film has, in order from the surface side, a polyethylene terephthalate resin layer/an alkali-soluble first intervening layer having a thickness of about 2 μm/a nylon resin layer having a thickness of 15 μm/an alkali-soluble second intervening layer having a thickness of about 2 μm/ It has a laminated structure of polyethylene resin layers.

Using the packaging film of Example 3, the peel strength was measured in the same manner as in Example 1. The 180° peel strength was 4.0 N/15 mm, indicating that the film was adhered with sufficient strength.

Next, the packaging film of Example 3 was cut into length x width = 60 mm x 100 mm to prepare several identical sample pieces, and these sample pieces were immersed in a 1.5 wt% sodium hydroxide aqueous solution at 85°C. Then, simple stirring was continued while maintaining the temperature, and one sample piece was taken out every 20 minutes to check the peelability between the layers.

As a result, the nylon resin layer and the polyethylene resin layer peeled off without any resistance after 20 minutes from the start of the immersion. Similarly, after 20 minutes, the polyethylene terephthalate resin layer and the nylon resin layer were peeled off without any resistance.

[Example 4]
In the coating agent of Example 3, 1 part by weight of vinyl chloride-vinyl acetate copolymer (manufactured by Nissin Chemical Industry Co., Ltd., trade name "Solbin TA5R") was added by 1 part by weight, and the blending amount of isopropyl alcohol was changed to 19 parts by weight. A packaging film was produced in the same manner as in Example 3, except that it was used as a part. The apparent acid value of this coating agent is 56 mg-KOH/g.

Using the packaging film of Example 4, the peel strength was measured in the same manner as in Example 1. The 180° peel strength was 4.5 N/15 mm, indicating that the film was adhered with sufficient strength.

Next, the packaging film of Example 4 was cut to length x width = 60 mm x 100 mm to prepare several same sample pieces, and these sample pieces were immersed in a 1.5 wt% sodium hydroxide aqueous solution at 85 ° C. Then, simple stirring was continued while maintaining the temperature, and one sample piece was taken out every 20 minutes to check the peelability between the layers.

As a result, the nylon resin layer and the polyethylene resin layer peeled off without any resistance after 20 minutes from the start of the immersion. Similarly, after 20 minutes, the polyethylene terephthalate resin layer and the nylon resin layer were peeled off without any resistance. Moreover, when the packaging film before immersion was visually observed, the uniformity of the laminated structure was high and the design was excellent.

[Example 5]
A packaging film was produced in the same manner as in Example 2 using the coating agent prepared in Example 3. The produced packaging film has a laminated structure of nylon resin layer/alkali-soluble intervening layer having a thickness of about 1 μm/printing ink layer/adhesive layer/polyethylene resin layer in order from the surface side.

Using the packaging film of Example 5, the peel strength was measured in the same manner as in Example 1. The 180° peel strength was 4.0 N/15 mm, indicating that the film was adhered with sufficient strength.

Next, the packaging film of Example 5 was cut into length x width = 60 mm x 100 mm to prepare one sample piece. This sample piece was immersed in a 1.5% by weight sodium hydroxide aqueous solution at 85° C., and simple stirring was continued while maintaining the temperature, and peeling of the nylon layer and the polyethylene layer was observed every 20 minutes.

As a result, the nylon layer and the polyethylene layer were separated after 20 minutes from the start of immersion.

[Example 6]
A packaging film was produced in the same manner as in Example 2 using the coating agent prepared in Example 4. The produced packaging film has a laminated structure of nylon resin layer/alkali-soluble intervening layer having a thickness of about 1 μm/printing ink layer/adhesive layer/polyethylene resin layer in order from the surface side.

Using the packaging film of Example 6, when the peel strength was measured in the same manner as in Example 1, the 180° peel strength was 4.5 N/15 mm, indicating that the film was adhered with sufficient strength.

Next, the packaging film of Example 6 was cut into length x width = 60 mm x 100 mm to prepare one sample piece. This sample piece was immersed in a 1.5% by weight sodium hydroxide aqueous solution at 85° C., and simple stirring was continued while maintaining the temperature, and peeling of the nylon layer and the polyethylene layer was observed every 20 minutes.

As a result, the nylon layer and the polyethylene layer were separated after 20 minutes from the start of immersion. Moreover, when the packaging film before immersion was visually observed, the uniformity of the laminated structure was high and the design was excellent.

[Comparative example]
Nylon resin layer/printing ink layer/adhesive layer/polyethylene resin in order from the surface side in the same manner as in Example 2 except that no coating agent was applied (no alkali-soluble intervening layer was formed). A layered packaging film was produced.

When the peel strength of the packaging film of the comparative example was measured in the same manner as in Example 1, the 180° peel strength was 4.0 N/15 mm, indicating that the film was adhered with sufficient strength. In addition, the packaging film of the comparative example was immersed in a 1.5% by weight sodium hydroxide aqueous solution at 85°C in the same manner as in Example 2, and the state of peeling between the layers was observed. and polyethylene layer separation could not be confirmed.

REFERENCE SIGNS LIST 1 packaging film 21, 22, 23, 24 base layer 3 intervening layer 41, 42 printing ink layer

Claims (4)

A pouch container comprising a packaging film,
The packaging film comprises at least two adjacent substrate layers,
The at least two adjacent base material layers comprise a first base material layer and a second base material layer made of a different material from the first base material layer,
The packaging film further comprises a water-soluble intervening layer between the first base layer and the second base layer,
The second base layer has sealant properties,
The intervening layer is a layer that allows the at least two adjacent base layers to be separated by solvent immersion,
The intervening layer is water-soluble and mainly composed of a polyvinyl alcohol-based resin,
the at least two adjacent substrate layers further comprising a third substrate layer between the first substrate layer and the second substrate layer;
The first base material layer has heat resistance,
the second base layer and the third base layer are made of different materials,
The intervening layers include a first intervening layer between the first base layer and the third base layer and a second intervening layer between the second base layer and the third base layer. A pouch container comprising : The third base layer has gas barrier properties,
The pouch container according to claim 1, wherein the first base material layer and the third base material layer are made of different materials. The at least two adjacent substrate layers further comprise the third substrate layer and the fourth substrate layer between the first substrate layer and the second substrate layer, and the first substrate layer, the third base layer, the fourth base layer and the second base layer are laminated in this order ,
The third base layer has gas barrier properties ,
the second base layer and the fourth base layer are made of different materials,
the third base layer and the fourth base layer are made of different materials,
The intervening layers include a third intervening layer between the second base layer and the fourth base layer, and a fourth intervening layer between the third base layer and the fourth base layer. The pouch container of claim 1, comprising: 4. The pouch container according to any one of claims 1 to 3, further comprising a printed layer formed on at least one surface of said at least two adjacent substrate layers.

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