JP7630240B2 - Composite film for forming self-supporting bags and self-supporting bags - Google Patents

Description

The present invention relates to a composite film for forming a structure and a self-supporting bag.

Standing pouches filled with liquids, solid-liquid mixtures, viscous materials, powders, granules, and other contents are highly compressible and flexible, and as such are finding increasing use in a wide range of fields as alternative containers to glass and plastic bottles.

Among these self-supporting bags, the self-supporting bag with a spout discharges the contents filled in the pouch through a spout attached to the pouch.

However, conventional self-supporting bags lacked rigidity, which meant that they could not stand upright when displayed on display, and the contents would spill out when the container was grabbed with the hand during the pouring process, and the entire container would bend when tilting the container to pour, causing the pouring outlet to become unstable.

In response to this, Patent Document 1 proposes a self-supporting bag (air-hold pouch) that has an independent air chamber with a handle function within the outer edge seal that forms the body of the bag. The self-supporting bag described in Patent Document 1 is said to improve the product's ability to stand on its own when displayed and its handling when pouring out the contents.

In addition to self-supporting ability and ease of handling, there are various other required characteristics for self-supporting bags, such as usability and burst strength.

JP 2006-036213 A

In this regard, the inventors came up with the idea of responding to various performance requirements by applying a functional material layer, in which a thermoplastic resin is impregnated or coated on a porous layer such as a porous film or nonwoven fabric, to the laminate that constitutes the self-supporting bag.

However, when a functional material layer having a porous layer is present in a self-supporting bag, pinholes are likely to occur during bag manufacturing. In particular, in the case of self-supporting pouch-type bags with spouts, pinholes can occur due to stress when attaching the spout or heat caused by sealing, which can cause the contents to leak.

The present invention has been made in view of the above background, and aims to provide a composite film for forming a structure, which does not generate pinholes during bag making to form a self-supporting bag, even if the self-supporting bag has a functional material layer with a porous layer, and in particular, even when forming a self-supporting bag in the form of a spouted pouch, the bag can be filled without generating pinholes, and a self-supporting bag made using the composite film for forming a structure.

The inventors of the present invention have conducted extensive research to solve the above problems. They have discovered that by using a layer in which a thermoplastic resin is impregnated or coated on a porous layer as a constituent material of a composite film for forming a structure such as a self-supporting bag, and by disposing an intermediate layer between the porous layer and a heat seal layer, pinholes do not occur even when stress is applied when attaching a spout, and bag filling is possible, which has led to the completion of the present invention. In other words, the present invention is as follows.

Aspect 1
A functional material layer, an intermediate layer, and a heat seal layer are laminated in this order, and
The functional material layer is a porous layer impregnated with or coated with a thermoplastic resin.
Composite film for forming structures.
Aspect 2
The composite film for forming a structure according to aspect 1, wherein the porous layer is a porous film or a nonwoven fabric.
Aspect 3
3. The composite film for forming a structure according to aspect 1 or 2, wherein the intermediate layer is a biaxially stretched film.
Aspect 4
The composite film for forming a structure according to any one of Aspects 1 to 3, wherein the thermoplastic resin has a melting point of 40 to 80° C.
Aspect 5
The composite film for forming a structure according to any one of Aspects 1 to 3, wherein the thermoplastic resin has a glass transition temperature of 40 to 80° C.
Aspect 6
6. The composite film for forming a structure according to any one of Aspects 4 and 5, wherein the thermoplastic resin is polycaprolactone.
Aspect 7
The composite film for forming a structure according to any one of Aspects 1 to 6, wherein tan δ ₈₀ ° C. /tan δ ₃₀ ° C., which is the ratio of the loss tangent tan δ _{80° C. at 80° C. to the loss tangent tan δ 30 ° C. at 30° C.} , is 1.04 to 5.00.
Aspect 8
Further comprising a substrate layer,
The composite film for forming a structure according to any one of Aspects 1 to 7, wherein the base material layer, the functional material layer, the intermediate layer, and the heat seal layer are laminated in this order.
Aspect 9
A self-supporting bag, at least a portion of which is made of the composite film for forming a structure according to any one of aspects 1 to 8.
Aspect 10
A self-supporting bag, at least the body portion being composed of the composite film for forming a structure according to any one of aspects 1 to 8.
Aspect 11
11. The self-supporting bag of claim 9 or 10, which is in the form of a spouted pouch.
Aspect 12
The self-supporting bag according to any one of aspects 9 to 11, which is used in a hot filling method.

The composite film for forming a structure of the present invention does not generate pinholes during bag making to form a self-supporting bag, even if it has a functional material layer with a porous layer. In particular, even when forming a self-supporting bag in the form of a spouted pouch, it is possible to fill the bag without generating pinholes.

Furthermore, by adjusting the ratio of the loss tangent tanδ _{80° C. at 80° C. to the loss tangent tanδ 30° C. at} 30° C., ie, tanδ _{80° C./tanδ 30° C.} , to a specific range, it is possible to prepare a self-supporting bag that is soft when filled with the contents by the hot filling method and that can maintain its self-supporting property when the contents decrease during use.

1 is a schematic cross-sectional view showing one embodiment of a composite film for forming a structure of the present invention. 1 is a photograph of the standing pouches produced in the examples and comparative examples. 1 is a photograph of a spout attached to a standing pouch produced in an example and a comparative example.

<<Composite film for forming structures>>
The composite film for forming a structure of the present invention includes a functional material layer, an intermediate layer, and a heat seal layer as essential constituent layers, which are laminated in this order. The functional material layer is formed by impregnating or coating a thermoplastic resin into a porous layer.

The composite film for forming a structure of the present invention has the above-mentioned configuration, so that even if it has a functional material layer with a porous layer, pinholes are not generated during bag making to form a self-supporting bag, and even when forming a self-supporting bag in the form of a spouted pouch, bag making and filling can be performed without generating pinholes.

Furthermore, the composite film for forming a structure of the present invention has a ratio of loss tangent tanδ at a specific temperature of the entire composite film for forming a structure within a specific range, making it possible to realize a self-supporting bag that is soft when filled with contents using the hot filling method and that can maintain its self-supporting properties as the contents decrease during use.

<Configuration of Composite Film for Forming Structure>
The configuration of the composite film for forming a structure of the present invention will be described below with reference to the drawings. Fig. 1 shows a schematic cross-sectional view of one embodiment of the composite film for forming a structure of the present invention.

The composite film 100 for forming a structure according to one embodiment of the composite film for forming a structure of the present invention shown in FIG. 1 includes a base layer 10, a functional material layer 20 laminated on the inner side of the base layer 10, an intermediate layer 30 laminated on the inner side of the functional material layer 20, and a heat seal layer 40 laminated on the inner side of the intermediate layer 30. The functional material layer 20 is composed of a porous layer 21 and a thermoplastic resin 22 impregnated or applied to the porous layer 21, and is laminated so that the surface impregnated or applied with the thermoplastic resin 22 is in contact with the intermediate layer 30.

The composite film for forming a structure of the present invention includes a functional material layer, an intermediate layer, and a heat seal layer as essential components, which are laminated in this order. In the present invention, in addition to the functional material layer, the intermediate layer, and the heat seal layer, any layer may be provided, and examples of such optional layers include a base layer and an adhesive layer.

The composite film 100 for forming a structure shown in FIG. 1 has a functional material layer 20, an intermediate layer 30, and a heat seal layer 40, which are essential constituent layers in the present invention, and also has a base layer 10 as an optional layer.

When the composite film for forming a structure of the present invention includes a base layer as an optional layer, it is preferable that the base layer, functional material layer, intermediate layer, and heat seal layer are laminated in this order.

The thickness, shape, etc. of the composite film for forming a structure of the present invention can be appropriately determined depending on the application site in the structure to be formed and the use of the structure to be formed.

<Function of composite film for forming structure>
In the composite film for forming a structure of the present invention, an intermediate layer is disposed between a specific functional material layer and a heat seal layer, so that even if the composite film has a functional material layer having a porous layer, pinholes are not generated during bag making to form a self-supporting bag. In particular, even when forming a self-supporting bag in the form of a spouted pouch, it is possible to form and fill the bag without generating pinholes.

Furthermore, when the ratio of the loss tangent tanδ at a specific temperature of the entire composite film for forming a structure is within a specific range, in addition to the above effects, it is possible to realize a self-supporting bag that is soft when filled with contents using the hot filling method, but is rigid enough to maintain its independence when the contents decrease during use.

Specifically, when the composite film for forming a structure of the present invention has a ratio of loss tangent tanδ _{80° C.} at 80° C. to loss tangent tanδ _{80° C.} at 30° C., tanδ _{80° C.} /tanδ _{30° C.} , in the range of 1.04 to 5.00, the bag is soft and easily expands at about 60 to 90° C. when the contents are filled by the hot filling method, so that the required amount of contents can be easily filled, and when the contents decrease with use in an environment of 30° C. or less, the bag has rigidity and can maintain its self-supporting property.

The ratio of the loss tangent tan δ _{80° C. at 80° C. to the loss tangent tan δ 30° C. at} 30° C., tan δ _{80° C.} /tan δ _{30° C.} , is preferably in the range of 1.05 to 4.00, more preferably in the range of 1.18 to 3.50.

<Functional material layer>
The functional material layer is an essential constituent layer in the composite film for forming a structure of the present invention. The composite film for forming a structure of the present invention has a functional material layer, and thus can meet various required properties such as self-supporting property, handling property, usability, and burst strength.

In the present invention, by adjusting the composition of the functional material layer, the physical properties of the entire composite film for forming a structure can be controlled, and for example, the ratio of the loss tangent tan δ at a specific temperature can be set to a specific range as described above. As a result, a self-supporting bag can be realized that is soft when filled with contents by the hot filling method, and that can maintain its self-supporting properties as the contents decrease during use.

(Configuration of Functional Material Layer)
The functional material layer constituting the composite film for forming a structure of the present invention has a configuration in which a thermoplastic resin is impregnated or coated on a porous layer.

In the functional material layer, the entire porous layer may be filled with thermoplastic resin, or a portion of the thermoplastic resin may be disposed inside the porous layer and a portion of the thermoplastic resin may be laminated on the surface of the porous layer.

The composite film 100 for forming a structure shown in FIG. 1 is a functional material layer 20 in which a portion of the thermoplastic resin 22 is disposed inside the porous layer 21 and a portion of the thermoplastic resin 22 is laminated on the surface of the porous layer 21.

In the composite film 100 for forming a structure according to one embodiment of the composite film for forming a structure of the present invention shown in FIG. 1, the functional material layer 20 is disposed between the base material layer 10 and the intermediate layer 30. The functional material layer 20 is composed of a porous layer 21 and a thermoplastic resin 22 impregnated or applied to the porous layer 21, and the heat seal layer 40 is disposed so that the surface impregnated or applied with the thermoplastic resin 22 faces the intermediate layer 30 and is adjacent to the intermediate layer 30.

In the functional material layer 20 in the composite film 100 for forming a structure according to one embodiment of the composite film for forming a structure shown in FIG. 1, the surface impregnated or coated with the thermoplastic resin 22 faces the intermediate layer 30, but in the present invention, the surface impregnated or coated with the thermoplastic resin may be located on either the intermediate layer side or the base layer side.

{Porous layer}
The porous layer constituting the functional material layer is a layer having a large number of voids. The voids may either penetrate the layer in the thickness direction or be discontinuous. In the present invention, by making the layer constituting the functional material layer a porous layer, the large number of voids present in the layer can be filled by impregnating or coating with a thermoplastic resin described below.

The form of the porous layer is not particularly limited, but it is preferably a porous film or nonwoven fabric.

The material constituting the porous layer is not particularly limited, but may be, for example, a polyester such as polyethylene terephthalate (PET) or polylactic acid, or a thermoplastic or thermosetting resin such as polyamide (PA) such as nylon-6 or nylon-66, or a natural material such as pulp.

When the porous layer is a nonwoven fabric made of fibers, any of needle punched nonwoven fabric, water jet punched nonwoven fabric, spunbonded nonwoven fabric, etc. can be used.

The basis weight and thickness of the porous layer used in the present invention are not particularly limited and can be appropriately selected depending on the type and amount of thermoplastic resin to be impregnated or applied.

{Thermoplastic resin}
The thermoplastic resin impregnated or applied to the porous layer is not particularly limited as long as it is a material having thermoplastic properties. In the present invention, the "thermoplastic resin" includes not only thermoplastic resins but also thermoplastic elastomers.

Examples of thermoplastic resins include, but are not limited to, paraffin wax, polycaprolactone, polyester, polyamide, polylactic acid, and thermoplastic elastomers.

In the present invention, the physical properties of the entire composite film for forming a structure can be controlled by adjusting the type and amount of the thermoplastic resin impregnated or applied to the porous layer, and for example, the ratio of the loss tangents tan δ described above can also be controlled.

In the composite film for forming a structure of the present invention, the ratio of the loss tangent tanδ _{80° C. at 80° C. to the loss tangent tanδ 30° C. at} 30° C., tanδ _{80° C.} /tanδ _{30° C.} , is in the range of 1.04 to 5.00, for example, by using a material having a melting point in a specific range as the thermoplastic resin. That is, the functional material layer contains a thermoplastic resin having a melting point in a specific range.

Specifically, it is preferable to impregnate or coat the porous layer with a thermoplastic resin having a melting point in the range of 40 to 80°C. It is more preferable that the melting point of the thermoplastic resin is in the range of 40 to 70°C, and particularly preferably in the range of 40 to 60°C.

Examples of substances with a melting point in the above range include fats and oils such as polycaprolactone, saturated fatty acids, or fatty acid triglycerides, higher alcohols, waxes, and surfactants (anionic, cationic, nonionic), etc.

Another method for making the ratio of the loss tangent tanδ _80°C at _{80°C to the loss tangent tanδ 30°C} at 30°C, tanδ _80°C /tanδ _30°C , fall within the range of 1.04 to 5.00 is to impregnate or coat the porous layer with a material having a glass transition temperature (Tg) in a specific range as a thermoplastic resin. That is, the functional material layer contains a thermoplastic resin having a glass transition temperature (Tg) in a specific range.

Specifically, it is preferable to impregnate or coat the porous layer with a thermoplastic resin having a glass transition temperature (Tg) of 40 to 80°C. It is more preferable that the glass transition temperature (Tg) of the thermoplastic resin is in the range of 40 to 70°C, and particularly preferably in the range of 40 to 60°C.

Examples of materials having a glass transition temperature (Tg) in the above range include polycaprolactone, specific grades of shape memory polymers (SMP), polyamide, or polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid. The shape memory resin (SMP) is preferably thermoplastic.

(Impregnation or coating method)
The method for impregnating or coating the thermoplastic resin into the porous layer is not particularly limited, and any known method can be used, such as gravure coating, dipping, suction, air knife coating, die coating, comma coating, fountain coating, gravure offset, etc.

(Amount of impregnation or application)
The amount of thermoplastic resin to be impregnated or applied to the porous layer is not particularly limited, and can be appropriately selected depending on the basis weight, pore size, thickness, and type of thermoplastic resin of the porous layer, as well as the physical properties of the composite film for forming a structure to be formed.

<Middle class>
The intermediate layer is an essential layer in the composite film for forming a structure of the present invention. The intermediate layer is disposed between the functional material layer and the heat seal layer, and serves to reinforce the strength of the functional material layer including the porous layer.

The composite film for forming a structure of the present invention has an intermediate layer between the functional material layer and the heat seal layer, so that even if the functional material layer has a porous layer, pinholes are not generated during bag making to form a self-supporting bag, and even when forming a self-supporting bag in the form of a spouted pouch, bag making and filling can be carried out without generating pinholes.

In the composite film 100 for forming a structure according to one embodiment of the composite film for forming a structure of the present invention shown in FIG. 1, the intermediate layer 30 is disposed between the functional material layer 20 and the heat seal layer 40.

The intermediate layer is not particularly limited, but is preferably a solid resin film, and more preferably a biaxially stretched film.

The material constituting the intermediate layer is not particularly limited, but may be, for example, polyethylene terephthalate (PET), polyester such as polylactic acid, or polyamide (PA) such as nylon-6 or nylon-66.

In the present invention, the thickness of the intermediate layer is not particularly limited, and can be set appropriately depending on the strength of the functional material layer to be used in combination.

<Heat seal layer>
The heat seal layer is an essential layer in the composite film for forming a structure of the present invention. The heat seal layer is a layer that is heat-sealed when forming a structure such as a self-supporting bag. For this reason, the heat seal layer is disposed so as to be the innermost layer of the composite film for forming a structure.

There are no particular limitations on the material that constitutes the heat seal layer, so long as it is capable of thermal adhesion and can impart sufficient seal strength to the molded structure. Known materials can be used, such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polypropylene (PP), ethylene-propylene copolymer (EP), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ionomer resin, ethylene-vinyl acetate copolymer (EVA), etc.

For example, when forming a structure such as a self-supporting bag filled with contents, the heat seal layer constituting the composite film for forming a structure of the present invention becomes a layer that forms a space for filling the contents. Therefore, when it is desired to impart resistance to contents, it is preferable to use, for example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc.

The heat seal layer may be formed using a film preformed from the above materials, or may be formed by melting and extruding the material for forming the heat seal layer onto the surface of a laminate in which a functional material layer, an intermediate layer, and other layers as necessary are laminated, and then cooling and solidifying the material.

The resins constituting the heat seal layer may be of one type or a blend of two or more types, and additives for imparting functionality, etc., may be added as necessary.

<Base layer>
The substrate layer is an optional layer in the composite film for forming a structure of the present invention. The composite film for forming a structure of the present invention has the functional material layer, the intermediate layer, and the heat seal layer as essential constituent layers, but may also include a substrate layer in addition to these.

When the composite film for forming a structure of the present invention has a base layer, it is preferable that the base layer, functional material layer, intermediate layer, and heat seal layer are laminated in this order.

In an embodiment in which the base material layer, functional material layer, intermediate layer, and heat seal layer are laminated in this order, the base material layer becomes the outer layer of the bag body when a structure such as a self-supporting bag is formed. Therefore, it can serve as a protective layer when the innermost heat seal layer is heat-sealed to form a structure. It can also serve as a printing layer for applying printing to display the contents, etc.

The material constituting the base layer is not particularly limited as long as it is a resin, particularly a resin that can be used as a protective layer and can be printed on. Commonly used resins can be used, for example, polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT), polyolefins such as polyethylene (PE), polypropylene (PP), and polystyrene (PS), polyamides (PA) such as nylon-6 and nylon-66, and polycarbonate (PC).

The resin constituting the base layer may be one type or a blend of two or more types, and additives may be added to impart functionality, etc., as necessary.

It is preferable that the base layer is made of a preformed film. The film that becomes the base layer may be a film formed from the above-mentioned resins, etc., and may be unstretched or uniaxially or biaxially stretched. Of these, a biaxially stretched film is preferable.

The film that serves as the base layer may also be vapor-deposited with a metal such as aluminum, or an oxide such as silicon oxide or aluminum oxide.

<Other demographics>
The composite film for forming a structure of the present invention may contain layers other than the functional material layer, intermediate layer, and heat seal layer as essential constituent layers. The other layers may be disposed between the essential constituent layers of the functional material layer, intermediate layer, and heat seal layer, or on the outside of the laminate containing these layers.

The other layers are not particularly limited, and examples include a barrier layer for imparting barrier properties to the structure being produced, a reinforcing layer for reinforcing the strength of the structure, and an adhesive layer for bonding between layers.

Examples of barrier layers that can be used to impart barrier properties to the structure being fabricated include layers made of ethylene-vinyl alcohol copolymer (EVOH), nylon (NY), polyvinylidene chloride (PVDC), or polyacrylonitrile (PAN), which exhibit the ability to block gases such as oxygen and water vapor.

Materials for the reinforcing layer to reinforce the strength of the structure to be produced include, for example, paper, synthetic paper, nonwoven fabric, etc. These may be coated with an adhesive to provide adhesion to adjacent layers.

Examples of adhesive layers for bonding layers include layers made of ethylene-acrylic acid copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), and ionomer.

The adhesive layer may be a layer made of an adhesive used when dry laminating or hot melt laminating a functional material layer, an intermediate layer, a heat seal layer, etc.

The resins constituting the other layers may be one type or a blend of two or more types. In addition, additives for imparting functionality, etc. may be added as necessary.

<<Method for manufacturing composite film for forming structure>>
The method for producing the composite film for forming a structure of the present invention is not particularly limited, and any method capable of forming a laminated composite film may be used. Known methods may be adopted, such as dry lamination, hot melt lamination, extrusion lamination, and sandwich lamination.

Structure
The structure formed by using the composite film for forming a structure of the present invention is not particularly limited. Since the composite film for forming a structure of the present invention has an innermost layer as a heat seal layer, structures of various shapes can be formed by heat fusion.

For example, three-sided sealed bags, four-sided sealed bags, gusset packaging bags, pillow packaging bags, Gabeltop-type bottomed containers, Tetra Classic (registered trademark), Brick Pack (registered trademark), tube containers, lids, etc. Also, a zipper can be provided on the heat seal layer to make a zippered packaging bag.

In the present invention, it is preferable that the bag is a self-supporting bag at least a part of which is made of the composite film for forming a structure of the present invention. It is particularly preferable that the bag is a self-supporting bag at least the body of which is made of the composite film for forming a structure of the present invention.

Furthermore, it is preferable that the structure formed using the composite film for forming a structure of the present invention is a self-supporting bag in the form of a spouted pouch, i.e., a self-supporting bag with a spout.

The composite film for forming a structure of the present invention has an intermediate layer between the functional material layer and the heat seal layer, so that even if the functional material layer has a porous layer, pinholes are not generated during bag making to form a self-supporting bag, and even when forming a self-supporting bag in the form of a spouted pouch, bag making and filling can be carried out without generating pinholes.

In addition, when the composite film for forming a structure of the present invention has a ratio of loss tangent tanδ _{80° C. at 80° C. to loss tangent tanδ 30° C. at 30} ° C., tanδ _{80° C.} /tanδ _{30° C.} , of 1.04 to 5.00, it is preferable that the composite film is a self-supporting bag used in a hot filling method.

When the composite film for forming a structure of the present invention has the above physical properties, the resulting self-supporting bag is soft when filled with contents by the hot filling method, and can maintain its self-supporting nature as the contents decrease during use. Therefore, since the bag easily expands when filling with contents, it is easy to fill with the required amount of contents, while at the same time, since it has rigidity when the contents are used, it can maintain its self-supporting nature.

Applicable Contents
The contents that can be filled into the structure formed from the composite film for forming a structure of the present invention are not particularly limited as long as they are liquids including gels, gels, pastes, etc. Examples of liquids include medicines, quasi-drugs, cosmetics, detergents, foods, paints, etc.

Examples of pharmaceuticals and quasi-drugs include injections, drip infusions, infusions, irrigation drugs, and decoctions. Examples of cosmetics include shampoos, conditioners, and hair styling products (e.g., hair water, hair liquid, grease, etc.). Examples of detergents include neutral detergents, alkaline detergents, and acidic detergents. Examples of foods include beverages, edible oils, soups, creams, and liquid seasonings (e.g., soy sauce, vinegar, noodle soup, warishita, mirin, Worcestershire sauce, ketchup, Tabasco, sweeteners, etc.). Examples of paints include paints, varnishes, and oil stains.

The contents may be in the form of a gel, gel or paste, for example toothpaste, wasabi, jelly, jam, miso, etc.

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these.

Examples 1 to 4 and Comparative Examples 1 to 5
<Ingredients>
The following materials were prepared to form the layers:

(1) Base layer PET#12: PET film (Emblet (registered trademark) PET-12, Unitika Ltd., thickness: 12 μm)
Ny#15: Nylon film (RX, Kohjin Film & Chemicals Co., Ltd., thickness: 15 μm)

(2) Functional Material Layer Porous Layer Polylactic acid nonwoven fabric (Terramac (registered trademark) L0303, Unitika Ltd., basis weight: 30 g/m ² )
Paper 40g: Pure white roll paper (basis weight: 40g/ ^m2 )
Thermoplastic resin PCL: Polycaprolactone (Placcel (registered trademark) H1P, Daicel Corporation)

(3) Intermediate layer NY: biaxially oriented nylon film (Bonyl (registered trademark), Kohjin Film & Chemicals Co., Ltd., thickness: 15 μm)
VM-PET#12: Aluminum-deposited PET film (VM-PET BR-1012, Toray Advanced Film Co., Ltd., thickness: 12 μm)

(4) Heat seal layer LL#50: LLDPE film (SE625L, Tamapoly Co., Ltd., thickness: 50 μm)
LL#80: LLDPE film (SE625L, Tamapoly Co., Ltd., thickness: 80 μm)
LL#95: LLDPE film (SE620A, Tamapoly Co., Ltd., thickness: 95 μm)
LL#100: LLDPE film (SE625L, Tamapoly Co., Ltd., thickness: 100 μm)
LL#45: [Extruded PE#15/LL#30] laminated film (thickness: 45 μm)
(Extruded PE: Suntec (registered trademark) L1850K, Asahi Kasei Corporation LL#30: LLDPE film (SE625L, Tamapoly Corporation, thickness: 30 μm)
LL#65: [Extruded PE#15/LL#50] laminated film (thickness: 65 μm)
(Extruded PE: Suntec (registered trademark) L1850K, Asahi Kasei Corporation LL#50: LLDPE film (SE625L, Tamapoly Corporation, thickness: 50 μm)

<Production of Functional Material Layer>
40 g of polylactic acid nonwoven fabric or paper to be a porous layer was attached to the base layer by dry lamination so as to obtain the lamination order shown in Table 1. As the adhesive for dry lamination, a two-component curing type dry lamination adhesive (Takelac A525/Takenate A52, Mitsui Chemicals, Inc.) was used.

In Table 1, the parts that were dry laminated are indicated with "//".

A coating liquid was prepared by dissolving polycaprolactone (PCL), a thermoplastic resin, in toluene. The prepared coating liquid was gravure coated on a polylactic acid nonwoven fabric to be a porous layer at a coating amount of 5 g/ ^m2 to prepare the functional material layers of Examples 1 to 3 and Comparative Examples 1 to 3 laminated on the base layer. In addition, the functional material layer of Example 4 was prepared by gravure coating at a coating amount of 10 g/ ^m2 to prepare the functional material layer laminated on the base layer.

Similarly, the prepared coating liquid was gravure coated onto 40 g of paper so that the coating amount was 4.4 g/ ^m2 , thereby preparing a functional material layer used in Comparative Example 4.

<Production of Composite Film for Forming Structure>
A composite film for forming a structure was produced by bonding the intermediate layer and/or the heat seal layer by dry lamination in the lamination order shown in Table 1. As the adhesive for dry lamination, a two-component curing type dry lamination adhesive (Takelac A525/Takenate A52, Mitsui Chemicals, Inc.) was used.

<Measurement of loss tangent tan δ>
Using a dynamic viscoelasticity measuring device (DMA Q800, TA Instruments, Inc.), the loss tangent tanδ at 80°C and 30°C was measured for the composite films for forming a structure produced in each Example listed in Table 1, and tanδ _{80°C /tanδ 30°C, which is the ratio of the loss tangent tanδ 80°C} at 80°C to the loss tangent tanδ _{30° C} at ₃₀ °C, was calculated.

Specifically, the loss tangent tan δ was measured at 25 to 100° C., the value at 30° C. was taken as tan δ _{30° C.} at 30° C., the value at 80° C. was taken as tan δ _{80° C.} at 80° C., and the ratio thereof, tan δ _{80° C.} /tan δ _30° C., was calculated. Table 1 shows tan δ _{30° C. at 30} ° C., tan δ _{80° C.} at 80° C., and the ratio thereof, tan δ _{80° C.} /tan δ _{30° C.}

<Making a self-supporting bag>
Using a bag making and filling machine (OnPack13000US, Orihiro Co., Ltd.), a standing pouch with a spout as shown in Fig. 2 was produced and filled with water. The pouch dimensions were height (H) 135 mm × width (W) 90 mm × gusset depth 25 mm.

The spout attached to the pouch is molded from a polyethylene resin and has the shape shown in Figure 3. Figure 3(a) is a front photograph of the spout, Figure 3(b) is a bottom photograph, and Figure 3(c) is a top photograph. The conditions for producing the standing pouch with a spout were a heat seal temperature of 135°C, ultrasonic output of 250 J, and pressure of 0.55 MPa.

<Evaluation of bag filling suitability>
The bag-making and filling suitability of the produced standing pouches was evaluated according to the following evaluation criteria. The results are shown in Table 1.
〇: No leakage from the standing pouch ×: Leakage from the standing pouch

<Assessment of independence>
After the contents were cooled to room temperature and then discharged all at once, the self-supporting ability of the standing pouch was evaluated according to the following criteria. The results are shown in Table 1.
○: Be independent
×: Not self-supporting

As shown in Table 1, the self-supporting bags made from the composite films for forming structures in Examples 1 to 4 had an intermediate layer between the functional material layer and the heat seal layer, and therefore in addition to being self-supporting, they also had excellent spout attachment suitability, no liquid leakage from the pouches produced, and excellent bag making and filling properties.

On the other hand, the self-supporting bags made from the composite film for forming a structure in Comparative Examples 1 to 4 had excellent self-supporting properties due to the presence of a functional material layer, but pinholes occurred during filling, especially in the spout attachment area, and liquid leakage was observed from the pouch.

In addition, the self-supporting bag of Comparative Example 5, which did not have a functional material layer, was not self-supporting.

REFERENCE SIGNS LIST 100 Composite film for forming structure 10 Base material layer 20 Functional material layer 21 Porous layer 22 Thermoplastic resin 30 Intermediate layer 40 Heat seal layer

Claims (8)

A base layer, a functional material layer, an intermediate layer, and a heat seal layer are laminated in this order, and
The functional material layer is a porous layer impregnated with or coated with a thermoplastic resin,
the porous layer is a porous film or a nonwoven fabric,
The thermoplastic resin has a melting point of 40 to 80° C.
the intermediate layer is a solid resin film; and
The ratio of the loss tangent tanδ _80°C at 80°C to the loss tangent tanδ 30° _C at 30°C, tanδ _80°C /tanδ _30°C , is 1.04 to 5.00;
Composite film for forming self-supporting bags. The composite film for forming self-supporting bags according to claim 1, wherein the intermediate layer is a biaxially stretched film. The composite film for forming self-supporting bags according to claim 1 or 2, wherein the thermoplastic resin has a glass transition temperature of 40 to 80°C. The composite film for forming self-supporting bags according to any one of claims 1 to 3, wherein the thermoplastic resin is polycaprolactone. A self-supporting bag, at least a portion of which is made of the composite film for forming a self-supporting bag according to any one of claims 1 to 4 . A self-supporting bag, at least a body portion of which is made of the composite film for forming self-supporting bags according to any one of claims 1 to 4 . 7. The self-supporting bag according to claim 5 or 6 , which is in the form of a spouted pouch. The self-supporting bag according to any one of claims 5 to 7 , which is used in a hot filling method.

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