WO2020166685A1 - Packaging film and pouch container - Google Patents

Abstract

The present invention provides a packaging film in which at least two base material layers (21, 22) that are formed of different materials are laminated, and which is configured so as to comprise two adjacent base material layers and an intervening layer (3) that has solvent solubility, while being arranged between the two adjacent base material layers; the intervening layer (3) is capable of separating the two base material layers from each other by means of solvent immersion; and this packaging film, in which at least two base material layers that are formed of different materials are laminated, is easily recycled.　

Description

Packaging film and pouch container

The present invention relates to a packaging film used for forming a packaging material such as a pouch container.

Conventionally, various items such as foods, cosmetics and medicines are distributed in various packaging materials. Among the packaging materials, soft packaging materials such as pouch containers and pillow packaging bags are formed of a flexible packaging film. For the packaging film forming the soft packaging material, a laminate in which two or more base material layers made of different materials are laminated is usually used.

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

Since the base material layer of the packaging film is made of different materials, it is difficult to recycle it as a raw material unless it is separated for each base material layer. Patent Document 1 (Japanese Unexamined Patent Publication No. 2007-062786) discloses an easily peelable food packaging paper including a paper layer and a non-paper layer made of a resin film or a metal film that is adhered to the paper layer with a wax. Has been done. In such a wrapping paper, the paper layer and the non-paper layer can be separated by picking one of the paper layer and the non-paper layer and peeling it off from the other. However, in the method of peeling off and separating by hand, the recycling process requires a great deal of time and labor. 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 coat layer in order to peel the display printing ink layer from the base film. .. However, Document 2 does not disclose separation of two base material layers made of different materials.

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

The packaging film of the present disclosure is a packaging film in which at least two base material layers made of different materials are laminated, and is disposed between two adjacent base material layers and two adjacent base material layers, And an intervening layer having solubility in a solvent, the intervening layer being a layer capable of separating the two base material layers by immersion in a solvent. According to this packaging film, the two base material layers can be easily separated by immersing the packaging film in an appropriate solvent, and thus a packaging film that can be easily recycled can be provided.

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

In the preferred packaging film of the present disclosure, the intervening layer includes an acrylic acid copolymer resin.

In the preferred packaging film 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 printing ink layer formed on at least one base material layer.

In a preferred packaging film of the present disclosure, one 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.

The pouch container of the present disclosure is formed by using any one of the above packaging films. According to this pouch container, since the two base material layers can be easily separated, it is possible to provide a pouch container that can be easily recycled.

The packaging film of the present disclosure can easily separate two base material layers made of different materials by immersing the packaging film in an appropriate solvent. The packaging film of the present disclosure that can be separated for each different material and the pouch container using the same can be easily recycled.

FIG. 1 is a plan view in which a part of the packaging film is 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 sectional drawing which shows another example of the 2nd laminated structure of a packaging film. FIG. 8: is sectional drawing which shows another example of the 2nd laminated structure of a packaging film. FIG. 9: is sectional drawing which shows another example of the 2nd laminated structure of a packaging film. FIG. 10: is sectional drawing which shows another example of the 3rd laminated structure of a packaging film. FIG. 11: is sectional drawing which shows another example of the 3rd laminated structure of a packaging film. FIG. 12: is sectional drawing which shows another example of the 3rd laminated structure of a packaging film. FIG. 13: is sectional drawing which shows another example of the 3rd laminated structure of a packaging film. FIG. 14 is a cross-sectional view of a packaging film having two base material layers, in which the preliminary adhesive layer is provided in contact with the intervening layer. FIG. 15 is a cross-sectional view of a packaging film having three base material layers, in which the preliminary adhesive layer is provided in contact with the intervening layer. FIG. 16 is a cross-sectional view of a packaging film having four base material layers, in which the preliminary adhesive layer is provided in contact with the intervening layer. FIG. 17: is a perspective view which shows an example of the pouch container formed using the packaging film. FIG. 18: is a perspective view which shows an example of the pillow packaging bag formed using the packaging film.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the present specification, the term "first", "second", "third", etc. may be added to the head of the term, but this first etc. is added only to distinguish the term. Yes, and it has no special meaning such as order or superiority. In the present specification, the numerical range represented by “lower limit value X to upper limit value Y” means a lower limit value X or more and an upper limit value Y or less. When a plurality of the numerical ranges are described separately, it is possible to select an arbitrary lower limit value and an arbitrary upper limit value and set "arbitrary lower limit value to arbitrary upper limit value". The dimensions, scales and shapes of the layers and components shown in each figure 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 drawing. The front surface of each layer is the upper surface of each layer shown in each figure, and the back surface of each layer is the lower surface of each layer shown in each figure.

<Outline of packaging film>
The packaging film of the present disclosure is a packaging film in which at least two base material layers made of different materials are laminated. Specifically, the packaging film of the present disclosure is a laminated body including at least two adjacent base material layers and an intervening layer arranged between the two base material layers. The two base material layers are made of different materials different from each other. The intervening layer is interposed between two base material layers that are adjacent to each other in the thickness direction. The intervening layer is a layer that is soluble in the solvent and that allows the two base material layers to be separated by immersion in the solvent. The term “solvent-soluble” refers to a property of dissolving in a solvent.

In this way, the intervening layer is a layer that allows two adjacent base material layers to be separated when the packaging film is immersed in an appropriate solvent. However, in the solvent non-immersion state (state not immersed in the solvent), two adjacent base material layers are not separated. That is, the packaging film is a laminated body in which the adhered state of each layer such as the base material layer and the intervening layer is maintained so that it cannot be easily peeled off by human force in the solvent-unimmersed state. The term "adhesion" refers to a state in which two layers are bonded by a physical or/and chemical force, and the layers are bonded so that they cannot be easily peeled off manually.

The packaging film only needs to have at least two base material layers adjacent to each other, and may have three or more base material layers. In the case of having three or more base material layers, it is preferable that, in the three or more base material layers, the intervening layer is provided between each two adjacent base material layers. Further, in the packaging film, a printing ink layer may be formed on at least one base material layer selected from a plurality of base material layers (at least two base material layers), if necessary.

The printing ink layer is composed of an ink solidified film formed by directly printing a known ink on a substrate layer or the like by a known printing method. The printing ink layer is firmly adhered to the surface of the other side forming it. The printing ink layer may be colored or uncolored (colorless and transparent). The colored printing ink layer may be opaque or colored and transparent. In the base material layer on which the printing ink layer is formed, the intervening layer may be arranged between the printing ink layer and the base material layer, and the base material layer on which the printing ink layer is formed and the base material adjacent thereto. It may be arranged between the layers.

Here, in this specification, transparent means colorless transparent or colored transparent. "Transparent" means that a number of 12 points is printed on a white background paper with black ink on the back side of the layer to be measured, at a position 1 cm away from the back side. A state in which the target layer is transparent and the number can be identified from the front side. "Opaque" means a state in which the numbers arranged on the back surface side cannot be visually recognized from the front surface side (states in which numbers cannot be recognized) under the same conditions as described above.

As an index of transparency (colorless transparency or colored transparency), for example, total light transmittance can be used. For transparent (colorless transparent or colored transparent), for example, the total light transmittance is 70% or more, preferably 80% or more, more preferably 90% or more. However, the total light transmittance is a value measured by a measuring method in accordance with JIS K 7361:1997 (a test method for the total light transmittance of a plastic-transparent material) of a transparent measurement object. When the base material layer, the intervening layer or the printing ink layer itself cannot be measured, the measurement object is a support film having a total light transmittance of 90% or more measured according to the JIS standard. And

The base material layer, the intervening layer and the printing ink layer are all layered, but the base material layer is different from the intervening layer and the printing ink layer in that it can form a layer by itself. That is, the base material layer can maintain a layered state by itself, and the intervening layer and the printing ink layer form a layer in a state of being adhered to the base material layer (supported by the base material layer. However, by itself it is very brittle and cannot be maintained in a layered state by breaking with a slight force.

Wrapping film is flexible. The packaging film as a whole may be transparent or opaque. The packaging film may have heat shrinkability, but preferably, it has substantially no heat shrinkability. The heat shrinkability means the property of shrinking when heated to a desired temperature (for example, 70°C to 90°C).

Also, the plan view shape of the packaging film is a long strip as shown in FIG. The long strip is a substantially rectangular shape in a plan view whose length in the longitudinal direction is sufficiently longer than that in the lateral direction. For example, the length in the longitudinal direction is 3 times or more, preferably 5 times the length in the lateral direction. That is all. Specific dimensions of the long strip include, for example, a case where the length in the lateral direction is 100 mm to 3000 mm and the length in the longitudinal direction is 2 m to 500 m. The long strip-shaped packaging film is usually wound into a roll shape for storage and transportation, and 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 strip shape, and may be formed in a sheet shape in plan view (not shown). Examples of the sheet-like 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>
Next, some laminated structures of the packaging film of this indication are illustrated. 2 to 5 are cross-sectional views each showing an example of the first laminated structure of the packaging film. 2 to 5, in the packaging film 1, two base material layers (for convenience, referred to as a first base material layer 21 and a second base material layer 22) are laminated. The first base material layer 21 and the second base material layer 22 are base material layers made of different materials.

Specifically, in the packaging film 1 of FIG. 2, the first base material layer 21, the intervening layer 3, and the second base material layer 22 are laminated in this order from the front surface side (upper side in the drawing). 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 front 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 front surface side. .. In the packaging film 1 of FIG. 5, a colorless and transparent printing 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 front surface side. ..

The packaging film 1 in which the colored printing ink layer 41 is formed between the first base material layer 21 and the second base material layer 22 may have the following configuration, for example:
(A) In order to make the color of the colored printing ink layer 41 visible from the surface side of the packaging film 1, each layer arranged on the surface side of the colored printing ink layer 41 (for example, in FIG. 3). The first base material layer 21, the first base material layer 21 and the intervening layer 3) in FIG. 4 are transparent, and each layer arranged on the back surface side of the colored printing ink layer 41 is transparent or opaque. Is;
(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 (for example, in FIG. 3). The second base material layer 22 and the intervening layer 3, and the second base material layer 22 in FIG. 4) are transparent, and each layer disposed 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. Well (in this case, for example, even if the first base material layer 21 is opaque, the color can be visually recognized from the front surface side), or it may be formed on the back surface of the second base material layer 22 (in this case, , The color can be visually recognized from the back side even if the second base material layer 22 and the like are opaque). Further, the colored printing ink layer 41 may be formed between layers of the base material layer and on the front surface of the first base material layer 21 and/or the back surface of the second base material layer 22. The colorless and transparent printing ink layer 42 is not limited to being formed on the surface of the first base material layer 21, and may be provided between the first base material layer 21 and the second base material layer 22, or/and It may be formed on the back surface of the two 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 includes three base material layers (for convenience, referred to as a first base material layer 21, a second base material layer 22, and a third base material layer 23). In these packaging films 1, two adjacent base material layers are present in two sets, but at least one set of two adjacent base material layers are base material layers made of different materials, and preferably two. The two adjacent base material layers of the set are base material layers each made of a different material.

Specifically, the packaging film 1 of FIG. 6 has a first base material layer 21, an intervening layer 3, a third base material layer 23, an intervening layer 3, and a second base material layer 22 in order from the front surface side. And 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 second base material layer 22 are adjacent to each other. There is a relationship of 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 preferably made of different materials. The packaging film 1 of FIG. 7 has a first base material layer 21, a colored printing ink layer 41, an intervening layer 3, a third base material layer 23, an intervening layer 3 and a second base material layer in order from the front surface side. The base material layer 22 is laminated in this order. The packaging film 1 of FIG. 8 has a first base material layer 21, an intervening layer 3, a colored printing ink layer 41, a third base material layer 23, an intervening layer 3 and a second The base material layer 22 is laminated in this order. The packaging film 1 of FIG. 9 has a colorless and transparent printing 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 order from the front side. The base material layer 22 is laminated in this order.

The packaging film 1 in which the colored printing ink layer 41 is formed between the first base material layer 21 and the third base material layer 23 may have the following configuration (A) or (B), for example. :
(A) In order to make the color of the colored printing ink layer 41 visible from the surface side of the packaging film 1, each layer arranged on the surface side of the colored printing ink layer 41 is transparent, Moreover, 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 is transparent. Each layer used and arranged on the surface side of the colored printing ink layer 41 is transparent or opaque.

The colored printing ink layer 41 is not limited to being formed between the first base material layer 21 and the third base material layer 23, and may be formed between the third base material layer 23 and the second base material layer 22. It may be formed in. Also in the packaging film 1 having three base material layers, a colored printing ink layer 41 is formed on the surface of the first base material layer 21 as in the packaging film 1 having the two base material layers. May be formed on the back surface of the second base material layer 22, or between the base material layers, and the surface of the first base material layer 21 and/or the second base material layer 22. May be formed on the back surface of the. 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 may be formed between the base material layers or/and 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, in the packaging film 1, four base material layers (for convenience, referred to as a first base material layer 21, a second base material layer 22, a third base material layer 23, and a fourth base material layer 24) are laminated. Has been done. 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 are base material layers made of different materials, and preferably, The three sets of adjacent base material layers are base material layers made of different materials.

Specifically, the packaging film 1 of FIG. 10 has a first base material layer 21, an intervening layer 3, a third base material layer 23, an intervening layer 3, and a fourth base material layer 24 in order from the front surface side. 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 have 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. It has 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 material layer 21, the second base material layer 22, the third base material layer 23, and the fourth base material layer 24 are preferably made of different materials. The packaging film 1 of FIG. 11 has a first base material layer 21, a colored printing ink layer 41, an intervening layer 3, a third base material layer 23, an intervening layer 3, and a fourth base material layer in order from the front surface side. 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 has a first base material layer 21, an intervening layer 3, a colored printing ink layer 41, a third base material layer 23, an intervening layer 3, and a fourth base material layer in order from the front surface side. 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 has a colorless and transparent printing 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 fourth order from the surface side. 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 material layer 21 and the third base material layer 23 may have the following configuration (A) or (B), for example. :
(A) In order to make the color of the colored printing ink layer 41 visible from the surface side of the packaging film 1, each layer arranged on the surface side of the colored printing ink layer 41 is transparent, Moreover, 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 is transparent, In addition, each layer arranged on the surface side of the colored printing ink layer 41 is transparent or opaque.

The colored printing ink layer 41 is not limited to the case where it is formed between the first base material layer 21 and the third base material layer 23, and the third base material layer 23 and the fourth base material layer 24 It may be formed between and/or between the fourth base material layer 24 and the second base material layer 22. Also in the packaging film 1 having four base material layers, the colored printing ink layer 41 is formed on the surface of the first base material layer 21 as in the packaging film 1 having the two base material layers. May be formed on the back surface of the second base material layer 22, or between the base material layers, and the surface of the first base material layer 21 and/or the second base material layer 22. May be formed on the back surface of the. 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 may be formed between the base material layers or/and 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 structure in which a preliminary adhesive layer that complements the intervening layer is provided between the adjacent base material layers of the packaging film. Specifically, FIG. 14 is a cross-sectional view of a packaging film having two base material layers, in which the preliminary adhesive layer is provided in contact with the intervening layer. FIG. 15 is a cross-sectional view of a packaging film having three base material layers, in which the preliminary adhesive layer is provided in contact with the intervening layer. FIG. 16 is a cross-sectional view of a packaging film having four base material layers, in which the preliminary adhesive layer is provided in contact with the intervening layer.

When the intervening layer does not adhere or is difficult to adhere to the base material layer or the printing ink layer formed on the base material layer, between the intervening layer and the base material layer, and/or the intervening layer. A preliminary adhesive layer 5 is provided between the layer and the printing ink layer formed on the base material layer as required. In each of FIGS. 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 the present invention is not limited to this. The preliminary adhesive layer 5 may be provided between appropriate layers. The preliminary adhesive layer 5 is not limited to one layer, and may be provided between several layers.

Note that, although not particularly shown, the preliminary adhesive layer 5 may be arranged in the packaging film 1 as a packaging film in which five or more base material layers are laminated. Also for a packaging film having five or more base material layers, two base materials in which two adjacent base material layers are made of different materials and an intervening layer is provided between the layers are similar to the above. It is sufficient to have at least the material layer.

<Intervening layer>
The intervening layer has solvent solubility and is arranged between adjacent base material layers. For example, the intervening layer directly adheres to the back surface of one base material layer and the surface of the other base material layer between two adjacent base material layers to bind both base material layers. This aspect is shown, for example, in FIGS. 2, 5, 6, and 9. In addition, for example, the intervening layer is between two adjacent base material layers, and the back surface (or front surface) of the base material layer on which the print ink layer is formed and the base material layer on the other side. Directly adhere to the front surface (or back surface) and bind both base material layers through one printing ink layer. This aspect is shown, for example, in FIGS. 3, 4, 7, and 8. Further, for example, the intervening layer is formed between two adjacent base material layers, and the back surface (or front surface) of the print ink layer of one base material layer on which the print ink layer is formed and the print ink layer are formed. Further, the other base material layer is directly adhered to the front surface (or the back surface) of the printing ink layer, and both base material layers are bound via the one and the other printing ink layers.

If the intervening layer is difficult to directly adhere to the front surface or the back surface of the base material layer or the printing ink layer in relation to the material of the base material layer or the printing ink layer, the above-mentioned preliminary adhesive layer is used. It is provided as appropriate. As described above, the preliminary adhesive layer is provided between the intervening layer and the base material layer and/or between the intervening layer and the printing ink layer. In this case, the preliminary adhesive layer and the intervening layer cooperate to bind two adjacent base material layers.

The solvent-soluble intervening layer has, for example, at least one property selected from water-soluble, alkali-soluble, and organic solvent-soluble, and preferably has at least one of water-soluble and alkali-soluble. 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 as the main component, and examples of such components include known additives and residual solvents.

Here, in the present specification, the main component of a certain layer refers to the most abundant component (weight ratio) 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, based on 100% by weight of the entire layer.

Since the intervening layer contains the solvent-soluble polymer as a main component, when the packaging film is immersed in the solvent, the solvent-soluble polymer in the intervening layer will be eluted from the base material layer into the solvent. Thereby, the intervening layer gradually reduces or eliminates the function of binding the layers or the function of binding the base material layers in cooperation with the preliminary adhesive layer. Therefore, the two base materials adjacent to each other with the intervening layer interposed therebetween are easily separated.

A solvent-soluble polymer is a polymer that is soluble in a given solvent. Examples of the solvent-soluble polymer include a water-soluble polymer, an alkali-soluble polymer, an organic solvent-soluble polymer and the like, and preferably at least one of a water-soluble polymer and an alkali-soluble polymer is used. The intervening layer containing a water-soluble polymer as a main component is water-soluble, and the intervening layer containing an alkali-soluble polymer as a main component is alkali-soluble.

The water-soluble polymer is a polymer which is soluble in water or an aqueous solvent at room temperature and atmospheric pressure, for example, a polymer having a solubility in water at 23° C. and 1 atm of 1 (g/100 g) or more, preferably the same solubility. Is a polymer of 5 (g/100 g) or more. Further, the water-soluble polymer is preferably one that 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. As the synthetic resin, polyvinyl alcohol resins such as polyvinyl alcohol and modified polyvinyl alcohol, polyvinyl acetate resins, cellulose resins, acrylic resins, polyacrylamide resins, polyethylene oxide resins, polyurethane resins, amino resins, And so on. Examples of natural polymers include polysaccharides such as starch and polypeptides, glue, casein, and natural rubber. These may be used alone or in combination of two or more.

The water-based solvent is a mixed solvent containing water and a hydrophilic solvent. The hydrophilic solvent is a solvent that can be uniformly dissolved in water. Examples of the hydrophilic solvent 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 which is soluble in an alkaline aqueous solution at room temperature and atmospheric pressure, and has a solubility of 1 (g in an alkaline aqueous solution (sodium hydroxide aqueous solution having a concentration of 1.5% by weight)) at 23° C. and 1 atm. /100 g) or more, preferably the same solubility is 5 (g/100 g) or more. Further, the alkali-soluble polymer is preferably one whose solubility in the alkaline aqueous solution heated to an appropriate temperature is improved. 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 kinds of unsaturated carboxylic acids and one or more kinds of compounds having a polymerizable unsaturated group. .. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid. Examples of the compound having a polymerizable unsaturated group include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, 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-methylolacrylamide and N-methylolmethacrylamide; styrene compounds such as styrene, vinyltoluene, α-methylstyrene and divinylbenzene; Examples thereof include olefins such as ethylene; allyl group-containing compounds such as diallyl phthalate, allyl glycidyl ether, and triallyl isocyanurate; vinyl esters such as vinyl acetate; 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 having an acrylic acid copolymer resin having an acid value of (mg-KOH/g) as a main component is preferable.

As the styrene-maleic anhydride resin, a known styrene-maleic anhydride resin can be used. For example, as a suitable styrene-maleic anhydride-based resin, a known styrene-maleic anhydride copolymer, which is a copolymer of styrene and maleic anhydride, and a modified product of the styrene-maleic anhydride copolymer (for example, , Partially esterified partially esterified products, etc.) and the like. In the styrene-maleic anhydride copolymer, styrene may be styrene or a styrene compound such as α-methylstyrene.

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

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

Examples of the copolymerization monomer 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 ester such as t-butyl (meth)acrylate [preferably lower alkyl ester of (meth)acrylic acid]; hydroxyl group-containing (meth)acrylate such as hydroxyethyl (meth)acrylate; glycidyl (meth) 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)acrylates; Styrenes such as styrene, vinyltoluene 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; Itaconic acid, Examples thereof include 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. The copolymerization monomers can be used alone or in combination of two or more.

The intervening layer preferably has an acid value of 40 to 150 (mg-KOH/g). For example, when the intervening layer has an acrylic acid copolymer-based resin as a main component and the acrylic acid copolymer-based resin is a mixed resin of two acrylic acid copolymer-based resins, the intervening layer has an acid value of two types. The value is different from each acid value of the acrylic acid copolymer resin. Also, when the intervening layer contains a resin having an acid value in addition to the resin as the main component, the acid value of the intervening layer becomes a value different from the acid value of the resin as the main component. The acid value of the intervening layer changes depending on the acid value of the resin contained and the content ratio of each resin. 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.

The intervening layer preferably further contains a vinyl chloride-vinyl acetate copolymer in addition to the resin as the main component described above. 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 intervening layer is preferably 1 to 10% by weight, more preferably 2 to 5% by weight, based on 100% by weight of the entire intervening layer. 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 tends to be too high and handling tends to be difficult. The vinyl chloride-vinyl acetate copolymer preferably has an Mn (number average molecular weight) of 10,000 to 40,000, and more preferably 15,000 to 35,000. In this case, the improvement of the adhesiveness becomes remarkable.

The intervening layer of the present disclosure is particularly preferably a layer formed from a resin composition containing an acrylic acid copolymer 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 resin may be a mixed resin of two or more acrylic acid copolymer resins.

Also, as the alkali-soluble polymer, those described in Patent Document 2 (Japanese Patent Laid-Open No. 2003-084670)/BR> 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 the present specification, and in the present specification, due to space limitations, the description in Patent Document 2 is given. Is omitted. However, the description of at least [0011] to [0032] of Patent Document 2 is incorporated in this specification as it is. The alkali-soluble coat 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>
The preliminary adhesive layer is provided between the intervening layer and the base material layer and/or between the intervening layer and the printing ink layer, if necessary. The preliminary adhesive layer is not particularly limited as long as it can bond the two layers between the layers in which it is interposed, and a known adhesive can be used. For example, as the preliminary adhesive layer, a so-called dry laminating adhesive such as a solvent volatile adhesive, a solventless adhesive, or an anchor coating agent can be used.

<Base material layer>
Examples of the base material layer include a resin layer, a metal thin film layer, a non-woven 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 and the like. Polystyrene resin; polycarbonate resin; nitrile resin such as polyacrylonitrile; imide resin such as polyimide; vinyl chloride resin such as polyvinyl chloride and polyvinylidene chloride; acrylate resin such as polymethylmethacrylate; To be 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 the metal thin film layer 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 non-woven fabric layer include non-woven fabrics made of fibers in a sheet form by an adhesion method, a needle punch method, a spun bond method, a melt blow 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 the base material layer having such a gas barrier property, the gas barrier property can be imparted to the packaging film. Further, the low density polyethylene layer, the ethylene-propylene copolymer layer, the ethylene-olefin copolymer layer and the like have sealant properties (heat welding properties). By using such a base material layer having a sealant property (for example, a base material layer forming the outermost surface of the laminate), a sealant property can be imparted to the packaging film.

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

As described above, the two adjacent base material layers provided with the intervening layer are made of different materials. Here, the two base material layers made of different kinds of materials mean those made of materials different from each other as a main component, and the two base material layers made of the same kind of material are made of the same material as a main component. Say something.

For example, as a base material layer made of different materials, 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 The pulp may be a combination of different materials).

In addition, in the resin layer, the resin layers containing different resins as main components are in the relationship of the base material layer made of different materials. Similarly, in the metal thin film layer, the metal thin film layers containing different metals as main components are in the relationship of the base material layer made of different materials, and in the non-woven fabric layer, the non-woven fabric layers containing different fibers as main components are made of different materials. There is a relationship of the 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 are in a relationship of two base material layers made of different materials, each containing a different resin as a main component. Further, the metal thin film layer containing aluminum as a main component (aluminum foil) and the metal thin film layer containing copper as a main component (copper foil) are made of different metals as main components and have a relationship of two base material layers made of different materials. It is in. Further, the non-woven fabric layer containing rayon fibers as the main component and the non-woven fabric layer containing nylon as the main component are in the relationship of two base material layers made of different materials with different fibers as main components.

On the other hand, the resin layer containing polyethylene terephthalate as the main component and the non-woven fabric containing polyethylene terephthalate fiber as the main component are in the relationship of two base material layers containing the same resin as the main component and made of the same material.

In the packaging film 1 having two base material layers shown in FIGS. 2 to 5, for example, an arbitrary resin layer is used as the first base material layer 21 which is the front surface side base material layer, and the back surface side As the second base material layer 22 which is the base material layer, a resin layer made of a resin material different from this is used, and the intervening layer 3 having solvent solubility is provided between them.

In the packaging film 1 having the three base material layers shown in FIGS. 6 to 9, for example, an arbitrary resin layer is used as the first base material layer 21 which is the front surface side base material layer, and an intermediate resin layer is used. 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 back side base layer. A layer is used, and the intervening layer 3 having solvent solubility is provided between the first base material layer 21 and the third base material layer 23 and between the third base material layer 23 and the second base material layer 22, respectively. Has been.

A metal thin film layer, a non-woven fabric layer, or a paper layer may be used as the third base material layer 23. Furthermore, a base material layer made of the same kind of material may be used as the first base material layer 21 and the third base material layer 23, or a base made of the same kind of material as the third base material layer 23 and the second base material layer 22. A material layer may be used. Thus, in the packaging film 1 including two adjacent base material layers made of the same material, the solvent-soluble intervening layer 3 may be provided between the two base material layers made of the same material. Alternatively, or such an intervening layer may not be provided.

When the packaging film 1 having the three base material layers shown in FIGS. 6 to 9 is used as a pouch film forming a pouch container, for example, the following configuration can be adopted.
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 a gas barrier property such as a polyvinylidene chloride resin layer or a metal thin film layer;
A second base material layer 22 having a sealant property such as a low density polyethylene layer or an ethylene-propylene copolymer layer.

In the packaging film 1 having four base material layers shown in FIGS. 10 to 13, for example, an arbitrary resin layer is used as the first base material layer 21 which is the base material layer on the surface side, and an intermediate base material is used. A metal thin film layer is used as the third base material layer 23 that is a material layer, an arbitrary resin layer is used as the fourth base material layer 24, and a second base material layer 22 that is a base material layer on the back surface side. A resin layer made of a resin material different from this is used, between the first base material layer 21 and the third base material layer 23, between the third base material layer 23 and the fourth base material layer 24, and The intervening layer 3 having solvent solubility is provided between the base material layer 24 and the second base material layer 22.

A resin layer, a non-woven fabric layer, or a paper layer may be used as the third base material layer 23, or a metal thin film layer, a non-woven fabric layer, or a paper layer may be used as the fourth base material layer 24. Good. Further, as the first base material layer 21 and the third base material layer 23, base material layers made of the same material may be used, or as the third base material layer 23 and the fourth base material layer 24, base materials made of the same material. A material layer may be used, or as the fourth base material layer 24 and the second base material layer 22, base material layers made of the same material may be used. Thus, in the packaging film 1 including two adjacent base material layers made of the same material, the solvent-soluble intervening layer 3 may be provided between the two base material layers made of the same material. Alternatively, or such an intervening layer may not be provided.

When the packaging film 1 having the four base material layers shown in FIGS. 10 to 13 is used as a pouch film forming a pouch container, for example, the following configuration can be adopted.
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 a gas barrier property 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 a sealant property 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. For example, a solution prepared by dissolving a solvent-soluble polymer in an appropriate solvent is applied to one or both of the adjoining base material layers to form a uncured intervening layer, and then the solvent is removed by drying or the like. To do. Thereby, the two base material layers having the solvent-soluble intervening layer adjacent to each other are bonded to each other.

The method for applying the solution containing the solvent-soluble polymer is not particularly limited, and examples thereof include a conventionally known printing method and a coater method using an appropriate coater. The concentration of the solution containing the solvent-soluble polymer is not particularly limited, and the concentration may be adjusted so that the viscosity becomes appropriate according to the coating method.

<Use of packaging film>
The packaging film of the present disclosure can be generally used as a known packaging material (including a tack label and the like), and for example, it is used after being processed into a soft packaging material. A soft packaging material is a soft packaging material that wraps various articles. The soft wrapping material formed by using the wrapping film of the present disclosure is preferably one that wraps the article in a hermetically sealed manner, and typical examples of such soft wrapping material include a pouch container, a pillow wrapping bag, 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 which shows an example of the pillow packaging bag formed using the packaging film. The packaging film forming the pouch container A1, the pillow packaging bag A2, etc., uses a base material layer having a sealant property as the base material layer on the bottom surface (the surface located on the inner space side of the container and the packaging bag). Is preferred.

In the packaging film of the present disclosure, an intervening layer that is soluble in a solvent and that can separate the two base layers by immersion in a solvent is provided between the two base layers made of different materials. By immersing such a packaging film in an appropriate solvent, the intervening layer is dissolved and the base material layer made of different materials can be easily separated.

For example, in the packaging film, when an intervening layer having water solubility is used, the packaging film is immersed in water or an aqueous solvent, whereby water penetrates into the intervening layer from the end surface of the intervening layer, The adhesive force of the intervening layer gradually decreases or disappears. Thereby, the two base material layers made of different materials can be easily separated. For example, in a packaging film, when an intercalating layer having alkali solubility is used, by immersing the packaging film in an aqueous alkaline solution, alkali penetrates into the interstitial layer from the end surface of the interstitial layer, and The adhesive force gradually decreases or disappears. Thereby, the two base material layers made of different materials can be easily separated. Therefore, the packaging film can be separated for each material, and the packaging film can be easily recycled.

In another aspect, the present disclosure discloses that by immersing the packaging film, in which an intervening layer having solvent solubility is provided between two adjacent base material layers made of different materials, in a suitable solvent, each base material layer is formed. It provides a method of separating into. As is clear from the examples below, the intervening layer can separate the two base material layers at least 24 hours after immersion in the solvent.

The packaging film processed into the soft packaging material such as the pouch container can be separated into two adjacent base material layers via the intervening layer by immersing the packaging film in the form of the soft packaging material in an appropriate solvent. Preferably, if the soft wrapping material is arbitrarily cut into small pieces, they can be separated more quickly. As for the degree of fragmentation, the smaller the area, the shorter the time required for separation. When the packaging film of the present disclosure is cut into, for example, a small piece of 60 square cm, it is provided with an intervening layer that allows the two base material layers to be separated without any particular load within 24 hours at the latest after being immersed in the solvent. There is something.

Hereinafter, examples and comparative examples will be described to further detail the present disclosure. However, the present disclosure is not limited to the following examples.

[Example 1]
An aqueous solution of a water-soluble polymer (trade name "Nichigo G polymer" manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) (polymer concentration: 10 wt. %) was applied in a solid form with a thickness of about 3 μm using a gravure printing method to form a first intervening layer. Thereafter, 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 coated on the back surface of the aluminum foil in a solid shape with a thickness of about 3 μm by using a gravure printing method to form a second intervening layer. Thereafter, a low-density polyethylene film having a thickness of 80 μm (trade name “L4102” manufactured by Toyobo Co., Ltd.) was laminated and adhered to the second intervening layer to produce a laminate. Then, the entire laminated body 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/aluminum thin film layer/a water-soluble second intervening layer having a thickness of about 3 μm/a polyethylene resin layer is formed in order from the surface side. A packaging film having was prepared.

The packaging film of Example 1 was cut into a strip having a width of 15 mm to obtain a test piece, and the 180° peel strength of the test piece was measured. As a result, the 180° peel strength of the test piece was 4.0 N/15 mm, indicating that the test piece was bonded with sufficient strength. The peel strength was measured at a peeling speed of 200 mm/min using a tensile tester (trade name “Autograph” manufactured by Shimadzu Corporation). 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, but both showed the above values. , One value is described. The same applies to the following.

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

As a result, after 6 hours, the aluminum thin film layer and the polyethylene resin layer were peeled off without any resistance. Further, after 24 hours, the polyethylene terephthalate resin layer and the aluminum thin film layer were peeled off without any resistance.

[Example 2]
15 parts by weight of styrene-maleic anhydride resin (acid value: 270 mg-KOH/g) (Kawahara Yuka Co., Ltd., trade name "SMA17352P"), 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.

This coating agent is applied to the back surface of a 15 μm-thick nylon film (trade name “Emblem ON” manufactured by Unitika Ltd.) in a solid shape with a thickness of about 1 μm using a gravure printing method, and then hot air at about 80° C. The intervening layer was formed by drying with. Next, a white ink (trade name “Rio Alpha S” manufactured by Toyo Ink Co., Ltd.) was solid-printed on the back surface of the intervening layer with a thickness of about 1 μm using a gravure printing method. After that, a dry laminating adhesive (trade name “LX500” manufactured by DIC Graphics Co., Ltd.) was applied to the back surface of the printing ink layer in a solid shape with a thickness of about 3 μm using a gravure printing method, and then a solvent component was applied. A 70 μm thick polyethylene film (trade name “SE620” manufactured by Tama Poly Co., Ltd.) was laminated and adhered by volatilizing the adhesive to a dry state capable of adhering. Thus, a packaging film of a nylon resin layer/an alkali-soluble intervening layer/printing ink layer/adhesive layer/polyethylene resin layer having a thickness of about 1 μm was produced in this order from the surface side.

When the peeling strength was measured using the packaging film of Example 2 in the same manner as in Example 1, the 180° peeling strength was 4.0 N/15 mm, and it was adhered with sufficient strength.

Next, the packaging film of Example 2 was cut into length×width=60 mm×100 mm to produce one sample piece. This sample piece was dipped in a 1.5 wt% sodium hydroxide aqueous solution at 85° C., and simple stirring was continued while maintaining the temperature, and the peeled state 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 24 hours after the start of immersion.

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

Next, 33 parts by weight of the acrylic acid copolymer resin (acid value: 63 mg-KOH/g), and 3 parts by weight of cellulose derivative (trade name "RS-1sec" manufactured by COREA CNC, solid content 70) Part 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 resin is an alkali-soluble polymer. The apparent acid value of this coating agent is 57 mg-KOH/g.

The coating agent prepared as described above was used instead of the water-soluble polymer of Example 1, and a 15 μm thick nylon film (trade name “Emblem ON” manufactured by Unitika Ltd.) was used instead of the aluminum foil. A packaging film was produced in the same manner as in Example 1 except for the above. The produced packaging film is, 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.

When the peeling strength was measured using the packaging film of Example 3 according to the same method as in Example 1, the 180° peeling strength was 4.0 N/15 mm, and it was bonded with sufficient strength.

Next, the packaging film of Example 3 was cut into length×width=60 mm×100 mm to prepare some same sample pieces, and these sample pieces were dipped 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, and the peelability between the layers was confirmed.

As a result, 20 minutes after the start of immersion, the nylon resin layer and the polyethylene resin layer peeled off without any resistance. 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 (trade name "Solvine TA5R" manufactured by Nisshin Chemical Industry Co., Ltd.) was added, and the compounding amount of isopropyl alcohol was 19 parts by weight. A packaging film was produced in the same manner as in Example 3 except that the parts were used. The apparent acid value of this coating agent is 56 mg-KOH/g.

When the peel strength was measured using the packaging film of Example 4 according to the same method as that of Example 1, the 180° peel strength was 4.5 N/15 mm, and it was adhered with sufficient strength.

Next, the packaging film of Example 4 was cut into length×width=60 mm×100 mm to prepare some of the same sample pieces, and these sample pieces were dipped 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, and the peelability between the layers was confirmed.

As a result, 20 minutes after the start of immersion, the nylon resin layer and the polyethylene resin layer peeled off without any resistance. Similarly, after 20 minutes, the polyethylene terephthalate resin layer and the nylon resin layer were peeled off without any resistance. Further, when the packaging film before being dipped was visually observed, it was found that the laminated structure was highly uniform 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 a nylon resin layer/an alkali-soluble intervening layer having a thickness of about 1 μm/printing ink layer/adhesive layer/polyethylene resin layer in this order from the surface side.

When the peeling strength was measured using the packaging film of Example 5 in the same manner as in Example 1, the 180° peeling strength was 4.0 N/15 mm, and it was adhered with sufficient strength.

Next, the packaging film of Example 5 was cut into length×width=60 mm×100 mm to produce one sample piece. This sample piece was dipped in a 1.5% by weight aqueous sodium hydroxide solution at 85° C., and simple stirring was continued while maintaining the temperature, and the peeled state 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 when 20 minutes had passed since the start of the 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 a nylon resin layer/an alkali-soluble intervening layer having a thickness of about 1 μm/printing ink layer/adhesive layer/polyethylene resin layer in this order from the surface side.

When the peeling strength was measured using the packaging film of Example 6 in the same manner as in Example 1, the 180° peeling strength was 4.5 N/15 mm, and it was bonded with sufficient strength.

Next, the packaging film of Example 6 was cut into length×width=60 mm×100 mm to produce one sample piece. This sample piece was dipped in a 1.5% by weight aqueous sodium hydroxide solution at 85° C., and simple stirring was continued while maintaining the temperature, and the peeled state 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 when 20 minutes had passed since the start of the immersion. Further, when the packaging film before being dipped was visually observed, it was found that the laminated structure was highly uniform 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 the coating agent was not applied (no alkali-soluble intervening layer was formed). A layer of packaging film was made.

The peel strength of the packaging film of the comparative example was measured in the same manner as in Example 1, and the 180° peel strength was 4.0 N/15 mm, indicating that the packaging film was bonded with sufficient strength. The packaging film of the comparative example was immersed in a 1.5 wt% sodium hydroxide aqueous solution at 85° C. in the same manner as in Example 2 and the peeling state between the layers was observed. No separation of the polyethylene layer was confirmed.

1 Packaging Film 21, 22, 23, 24 Base Material Layer 3 Intervening Layer 41, 42 Printing Ink Layer

Claims (7)

1. A packaging film in which at least two base material layers made of different materials are laminated,
   Two adjacent base material layers,
   An intervening layer having solvent solubility disposed between the two adjacent base material layers,
   The said intervening layer is a packaging film which is a layer which can isolate|separate two base material layers by solvent immersion.
2. The packaging film according to claim 1, wherein the intervening layer has at least one of water solubility and alkali solubility.
3. The packaging film according to claim 1 or 2, wherein the intervening layer contains an acrylic acid copolymer resin.
4. The packaging film according to any one of claims 1 to 3, wherein the intervening layer has an acid value of 40 mg-KOH/g or more and 150 mg-KOH/g or less.
5. The packaging film according to any one of claims 1 to 4, wherein a printing ink layer is formed on the surface of at least one base material layer of the two adjacent base material layers.
6. In the two adjacent base material layers, one base material layer is a resin layer, and the other base material layer is a metal thin film layer or a resin layer. Wrapping film.
7. A pouch container formed using the packaging film according to any one of claims 1 to 6.

Images