Patent Description:
As disclosed in Patent Document <NUM>, for example, there is known a flexible container (sheet material container) made from a flexible material. The flexible material disclosed in Patent Document <NUM> includes a first laminate, a second laminate, and a seal by which the first laminate and the second laminate are partially attached. That is, the flexible material has a laminate structure. A structural support volume is defined in part between the first laminate and the second laminate, and a structural support frame is formed by filling the structural support volume with an expansion material such as air. The structure of the sheet material container is supported by this structural support frame. Thus, the thickness of the flexible material can be reduced. Therefore, waste can be reduced.

According to one aspect of the present invention, there is provided a sheet material container as defined in independent claim <NUM>.

Preferably, a tensile modulus of elasticity of the plurality of base material films is not less than <NUM> GPa at a room temperature, preferably not less than <NUM> GPa, and more preferably not less than <NUM> GPa. A total thickness of the attaching layer is preferably not more than <NUM>, and preferably not more than <NUM>.

The ratio of a total thickness of the plurality of base material films to the total thickness of the attaching layer may be larger than <NUM>, preferably not smaller than <NUM>, and more preferably not smaller than <NUM>.

The ratio of the total thickness of the plurality of base material films to the total thickness of the attaching layer may be not larger than <NUM>, preferably not larger than <NUM>, more preferably not larger than <NUM>, even more preferably not larger than <NUM>, and still more preferably not larger than <NUM>.

Each thickness of the plurality of base material films may be not less than <NUM>, preferably not less than <NUM>, and more preferably not less than <NUM>.

Each thickness of the plurality of base material films may be not more than <NUM>, preferably not more than <NUM>, and more preferably not more than <NUM>.

A melting point of the plurality of base material films may be different from a melting point of the attaching layer, the melting point of the plurality of base material films is preferably higher than the melting point of the attaching layer, the melting point of the plurality of base material films is higher than the melting point of the attaching layer more preferably by <NUM> or more, even more preferably by <NUM> or more, and still more preferably by <NUM> or more.

Preferably, the filler enclosed portion is in contact with one or both of the base material films of two layers between which the attaching layer is attached.

Preferably, printing is provided on any one or more base material films of the plurality of base material films.

Preferably, the plurality of base material films each have a single-layer structure.

Preferably, the filler enclosed portion includes a configuration extending in an up-down direction in the container body.

More preferably, at least one pair of the filler enclosed portions extending in the up-down direction of the container body are provided along both edge portions in a width direction of the container body on each side of opposite sides across the containing portion of the container body.

Preferably, a top gusset is formed at an upper end of the sheet material container, and a sheet member of the top gusset is attached to a base part of a spout provided with the base part. More preferably, the spout is made from the same type of resins as the plurality of base material films or the attaching layer. The filler enclosed portion may be adjacent to the base part of the spout on at least one of both sides across the containing portion of the container body. On at least one of both sides across the containing portion of the container body, at least one pair of the filler enclosed portions extending in the up-down direction of the container body may be brought into communication with each other through the filler enclosed portion extending in the width direction of the container body on the upper end of the container body, and the filler enclosed portion extending in the width direction is adjacent to the base part.

Preferably, the sheet material container comprises an inner container that is surrounded by the container body,
wherein the inner container has the containing portion, and is made from the same type of resins as the plurality of base material films.

There is a need for further improvement in environmental characteristics of not only the sheet material container disclosed in Patent Document <NUM>, but also various sheet material containers. As described above, the sheet material container disclosed in Patent Document <NUM> enables a reduction of waste, resulting in excellent in environmental characteristics. However, there has been a room for further improvement in the environmental characteristics, in particular from the standpoint of recycling.

The present invention relates to a sheet material container capable of improving recyclability while maintaining a function of the sheet material container.

As described above, the present invention enables improvement in the recyclability while maintaining the function of the sheet material container.

Hereinafter, preferred embodiments of the present invention will be described in detail, referring to the accompanying drawings. In the present specification and the accompanying drawings, constituent elements having substantially the same functional configuration are denoted by the same reference characters, and the duplicate description thereof will not be repeated.

An overall configuration of a sheet material container <NUM> according to the present embodiment will be described based on <FIG>. The configuration disclosed in <CIT>, for example, can be adopted as a configuration of the sheet material container <NUM> according to the present embodiment. Specifically, as illustrated in <FIG>, the sheet material container <NUM> includes an inner container <NUM> that accommodates a content <NUM> and has an opening <NUM> through which the content <NUM> can be discharged, a container body <NUM> that is formed of a container body-forming sheet member <NUM> in which a plurality of film layers <NUM> and <NUM> are layered and that covers (surrounds) the inner container <NUM>, and an outer air introducing part <NUM> through which outer air is introduced between an outer surface of the inner container <NUM> and an inner surface of the container body <NUM>.

In the sheet material container <NUM>, the container body <NUM> has a bottom gusset <NUM>, and is designed in a self-standing form. Of course, the sheet material container <NUM> is not limited to the self-standing form, but may be a form (pillow type) intended for use while being laid down, rather than being stood alone.

The inner container <NUM> is configured to accommodate the content <NUM> and discharge the content <NUM> from the opening <NUM> (more specifically, a spout <NUM> provided in the opening <NUM>). The content <NUM> may be of any type. Examples of the content <NUM> include not only shampoo, hair rinse, body soap, detergent, softener, beverage and food, but also engine oil and chemicals. The content <NUM> may be liquid (including paste), or may be solid (for example, particle (including granule), or powder).

The container body <NUM> covers the entirety of the inner container <NUM> illustrated in <FIG>, to form the outer surface of the sheet material container <NUM>. However, it is only required that the container body <NUM> covers at least a portion of the inner container <NUM>.

The container body-forming sheet member <NUM> includes a film region in which the plurality of film layers <NUM> and <NUM> are attached to each other. As illustrated in <FIG>, the film layer <NUM> includes a base material film 121a, and an attaching layer 121b, and the film layer <NUM> includes a base material film 122a, and an attaching layer 122b. Accordingly, it can be also said that the container body-forming sheet member <NUM> has a structure in which a plurality of base material films 121a and 122a are layered. A filler enclosed portion <NUM> into which a filler is to be filled is formed between the base material films 121a and 122a. A detailed layer configuration of the film layers <NUM> and <NUM> will be described later.

The filler enclosed portion <NUM> is formed continuously along peripheral edges of the container body <NUM>. When the filler is filled into the filler enclosed portion <NUM>, the rigidity as the sheet material container <NUM> is provided to the container body <NUM>. That is, high self-standing property and high compression strength are provided to the container body <NUM>. As a user discharges the content <NUM>, the inner container <NUM> contracts, but the container body <NUM> retains its shape. After fully consuming the content <NUM>, the user discharges the filler from the filler enclosed portion <NUM>. This causes the container body <NUM> to lose rigidity, whereby the user can easily flatten and fold the sheet material container <NUM> into a compact size. As a result, it is possible to expect the reduction of waste, and thus the reduction of environmental loads. Furthermore, the outer air introducing part <NUM> is formed in the sheet material container <NUM>, whereby the capacity of the inner container <NUM> can be easily reduced independently of the container body <NUM>. In this way, the content <NUM> in the inner container <NUM> can be easily discharged, and the content <NUM> can be prevented from remaining in the inner container <NUM>.

As described above, the filler enclosed portion <NUM> is formed continuously along the peripheral edges of the container body <NUM>. However, the container body-forming sheet member <NUM> may include a plurality of filler enclosed portions independent from one another. Besides the filler enclosed portion <NUM> and the film region, the container body-forming sheet member <NUM> may include an area where the plurality of film layers <NUM> and <NUM> are not attached to each other and that has no filler between the plurality of film layers.

It is more preferable that the filler enclosed portion <NUM> includes configurations extending in an up-down direction of the container body <NUM> as illustrated in both edge portions in a width direction of the container body <NUM> in the sheet material container <NUM> having a bottom illustrated in each of <FIG> and <FIG>, because the container rigidity can be increased to the degree that the function as the container can be sufficiently maintained even at the time of pumping. As used herein, the term "up-down direction" in the present embodiment refers to a direction in which the opening <NUM> and the bottom (an end opposite to the opening <NUM>) are connected. The term "width direction" refers to a direction orthogonal to the above-described up-down direction and a base material film layer stack direction, and is a shortside direction of the container body <NUM> in the embodiment of <FIG> and <FIG>. To further increase the container rigidity, at least one pair of (at least one pair of left and right) filler enclosed portions <NUM> extending in the up-down direction may be provided along both edge portions in the width direction of the container body <NUM> on each side of opposite sides across the containing portion of the container body <NUM> in the base material film layer stack direction.

The outer air introducing part <NUM> is formed in a boundary portion between a trunk <NUM> and a top gusset <NUM> of the container body <NUM>. For example, the outer air introducing part <NUM> is formed so that an inner container-forming sheet member <NUM> and the container body-forming sheet member <NUM> are not attached to each other in this portion, whereby the outer air introducing part <NUM> is formed. However, the outer air introducing part <NUM> may be solely owned by the container body <NUM>. In this case, the outer air introducing part <NUM> may be, for example, an opening formed in the container body <NUM>. Additionally, the sheet material container <NUM> may include a plurality of outer air introducing parts <NUM>.

As illustrated in <FIG>, the inner container <NUM> includes a top gusset <NUM> that is formed at an upper end of the inner container <NUM>, a bottom gusset <NUM> that is formed at a bottom of the inner container <NUM>, and a trunk <NUM> which is a portion between the top gusset <NUM> and the bottom gusset <NUM>. An inner space of the inner container <NUM> serves as the containing portion that accommodates the content <NUM>.

The inner container <NUM> is formed into a shape as illustrated in <FIG>, by folding the inner container-forming sheet member <NUM> illustrated in <FIG> and by attaching peripheral edge portions of the folded inner container-forming sheet member <NUM> to each other (for example, by heat sealing). Of course, the inner container <NUM> is not always necessarily formed of the sheet member, but may be formed by blow molding, for example.

The top gusset <NUM> has the opening <NUM> through which the content <NUM> in the containing portion can be discharged to outside. The top gusset <NUM> is provided with a cylinder part <NUM> of the spout <NUM> adapted to extend through the opening <NUM>, for example. Accordingly, the content <NUM> is discharged to outside through the spout <NUM> extending through the opening <NUM>. The bottom gusset <NUM> is formed at the end opposite to the opening <NUM> in the inner container <NUM>. The peripheral edge portion of the inner container <NUM> forms a sealed part <NUM> by attaching the peripheral edge portions of the inner container-forming sheet member <NUM> to each other.

The container body <NUM> is formed into a shape as illustrated in <FIG>, for example, by folding a container forming sheet <NUM> illustrated in <FIG> (a sheet member formed by layering and attaching the inner container-forming sheet member <NUM> and the container body-forming sheet member <NUM>) and by attaching the peripheral edge portions of the folded container body-forming sheet member <NUM> to each other or the peripheral edge portions of the folded inner container-forming sheet member <NUM> to each other.

The container body <NUM> includes the top gusset <NUM> that is formed at an upper end of the container body <NUM>, a bottom gusset <NUM> that is formed at a bottom of the container body <NUM>, and the trunk <NUM> which is a portion between the top gusset <NUM> and the bottom gusset <NUM>. The bottom gusset <NUM> covers a lower face side of the bottom gusset <NUM>, and is a portion that faces a placement surface when the sheet material container <NUM> is placed thereon in a self-standing manner. The top gusset <NUM> covers an upper face side of the top gusset <NUM>, and has an opening <NUM> through which the content <NUM> in the containing portion of the inner container <NUM> can be discharged. As described later, the top gusset <NUM> is provided with the cylinder part <NUM> of the spout <NUM> adapted to extend through the opening <NUM>. The trunk <NUM> surrounds the trunk <NUM>.

The peripheral edge portion of the container body <NUM> forms sealed parts <NUM> and <NUM>. In the sealed part <NUM>, the peripheral edge portions of the container body-forming sheet member <NUM> and the peripheral edge portions of the inner container-forming sheet member <NUM> are attached to each other. That is, the top gussets <NUM> and <NUM> are connected to each other, and the trunks <NUM> and <NUM> are connected to each other. Additionally, in the sealed part <NUM>, the peripheral edge portions of the inner container-forming sheet member <NUM> are attached to each other. Furthermore, in the sealed part <NUM>, the peripheral edge portions of the container body-forming sheet member <NUM> are attached to each other. Thereby, the container body <NUM> is formed into a container shape covering the entirety of the inner container <NUM>. The sheet material container <NUM> is configured to be capable of self-standing, when the bottom gusset <NUM> is placed on a horizontal placement surface.

In this way, the container body <NUM> and the inner container <NUM> are partially attached to each other. Since the inner container <NUM> is thus held by the container body <NUM>, the inner container <NUM> can be prevented from creasing even if the inner container <NUM> is made thin, and the inner container <NUM> is more easily collapsed flatly. Hence, the content <NUM> can be prevented from remaining in the inner container <NUM>.

However, the container body <NUM> and the inner container <NUM> are not necessarily attached over the entire range (the container body <NUM> and the inner container <NUM> are not attached at all). Even in this case, it is preferable that the inner container <NUM> is held inside the container body <NUM> by the container body <NUM>. For example, a configuration may be adopted in which the edge portions of the inner container-forming sheet member <NUM> are attached to each other by outer edge portions of the sealed part <NUM>, and the sealed part <NUM> is sandwiched between inner edge portions of the sealed part <NUM>.

The spout <NUM> includes a flat plate-shaped base part <NUM> that is attached to the inner surface side of the inner container <NUM>, and the cylinder part <NUM> that protrudes outside from the base part <NUM> through the opening <NUM> of the inner container <NUM> and the opening <NUM> of the container body <NUM>. An outer peripheral surface of the cylinder part <NUM> is threaded so that a pumping cap or a cap with a check valve can be installed to the spout <NUM>. It is preferable that the base part <NUM> of the spout <NUM> is attached to the sheet member of the top gusset <NUM> formed at the upper end of the inner container <NUM>. Furthermore, the base part <NUM> of the spout <NUM> may be configured to be attached to the sheet member of the top gusset <NUM> formed at the upper end of the container body <NUM>.

The filler enclosed portion <NUM> is formed continuously along the peripheral edge portion of the container body <NUM>, and the inside of the filler enclosed portion <NUM> is filled with the filler. Hereby, the rigidity as the sheet material container <NUM> can be provided to the container body <NUM>. A part of the filler enclosed portion <NUM> extends toward the peripheral edge portion of the container body <NUM> in the vicinity of the top gusset <NUM>. This part is a portion that is connected to a filler introducing part <NUM> when the filler is filled into the filler enclosed portion <NUM>.

Furthermore, it is preferable that the filler enclosed portion <NUM> is adjacent to the base part <NUM> of the spout <NUM> on at least one of both sides or preferably on each side of opposite sides across the containing portion of the container body <NUM> in the base material film lamination direction, because the container rigidity at the time of pumping can be further increased. It is further preferable that the container body <NUM> has the above-described configuration in addition to the filler enclosed portion <NUM> extending in the up-down direction. As used herein, the term "adjacent" refers to a state in which the sheet member that forms the filler enclosed portion <NUM> extending toward the upper end side of the container body <NUM> (an area on the opening <NUM> side when the container body <NUM> is divided equally into three areas in the up-down direction) is substantially in contact with the base part <NUM> of the spout <NUM>, as in the embodiment illustrated in <FIG> and <FIG>. That is, the term "adjacent" refers to the state in which the above-described sheet member forming the filler enclosed portion <NUM> is directly in contact with the base part <NUM> of the spout <NUM> or the above-described sheet member forming the filler enclosed portion <NUM> and the base part <NUM> of the spout <NUM> may be directly in contact with each other by pumping or a pressure load equivalent to the pumping in a state in which the filler is enclosed in the filler enclosed portion <NUM> (for example, only an inevitable gap caused by the formation of the container exists therebetween). <FIG> and <FIG> illustrate the embodiment in which the inner container <NUM> is not provided.

It is more preferable that on at least one of both sides or preferably on each side of opposite sides across the containing portion of the container body <NUM> in the base material film layer stack direction, at least one pair of filler enclosed portions <NUM> extending in the up-down direction of the container body <NUM> are brought into communication with each other through a filler enclosed portion <NUM> extending in the width direction of the container body <NUM> on the upper end side of the container body <NUM>, and the filler enclosed portion <NUM> extending in the width direction is adjacent to the base part <NUM>, because the filler enclosed portion <NUM> extending in the width direction can support the spout <NUM> at the time of pumping. For example, in the embodiment illustrated in <FIG> and <FIG>, the filler enclosed portion <NUM> that extends in the width direction on the upper end side of the container body <NUM> and through which the filler enclosed portions <NUM> extending in the up-down direction are brought into communication with each other is formed to be pressed to the base part <NUM> of the spout <NUM>. Furthermore, at least a part of the filler enclosed portion <NUM> extending in the width direction extends to an inner side of the container body <NUM> than an outer end of the base part <NUM> of the spout <NUM> (an end opposite to a side attached to the cylinder part <NUM>), and thereby supports the spout <NUM>. In this embodiment, a configuration may be adopted in which the inner container <NUM> is further provided.

The filler may be fluid (gas or liquid), solid (for example, particulate, resin pellet, etc.) or semi-solid (for example, foam material, etc.), and is preferably gas such as air. An internal pressure of the filler enclosed portion <NUM> may be any pressure, but it is preferably higher than the atmospheric pressure from the standpoint of providing sufficient rigidity to the container body <NUM>. The internal pressure can be set to, for example, preferably not lower than <NUM> kPa, more preferably not lower than <NUM> kPa, and not higher than <NUM> kPa, even more preferably not higher than <NUM> kPa, by gauge pressure conversion.

The container body-forming sheet member <NUM> forming the container body <NUM> is formed by layering and attaching the film layers <NUM> and <NUM> to each other (for example, by heat sealing), as illustrated in <FIG>, <FIG>, and <FIG>. Although the details will be described later, the attaching layer 121b of the film layer <NUM> is attached to the base material film 122a of the film layer <NUM>.

Here, the film layers <NUM> and <NUM> are not partially attached, whereby a non-attached portion <NUM> is formed. The non-attached portion <NUM> forms a space between the film layers <NUM> and <NUM>. When the space is filled with the filler, the filler enclosed portion <NUM> is formed. Accordingly, the non-attached portion <NUM> can be formed at any portion where the formation of the filler enclosed portion <NUM> is desired. As a method of forming the non-attached portion <NUM>, the following methods are mentioned, for example. That is, the non-attached portion <NUM> is formed by pattern-applying an attaching agent onto the base material film 121a. In this case, the non-attached portion <NUM> is in contact with both base material films 121a and 122a (that is, the filler enclosed portion <NUM> is in contact with both base material films 121a and 122a). After the attaching agent is applied to the entire surface of the base material film 121a, only a portion of the attaching layer 121b may be adapted to be attached to the base material film 122a by pattern heating or an adhesion inhibiting agent. In this case, the non-attached portion <NUM> is in contact with the base material film 122a (that is, the filler enclosed portion <NUM> is in contact with the base material film 122a). Furthermore, after the attaching agents are applied to the entire surfaces of the base material films 121a and 122a, at least portions of the attaching layer 121b may be adapted not to be attached to each other by pattern heating or an adhesion inhibiting agent. In this case, the non-attached portion <NUM> is not in contact with both base material films 121a and 122a (that is, the filler enclosed portion <NUM> is in contact with the attaching layer 121b). In the example illustrated in <FIG>, the filler enclosed portion <NUM> is in contact with both base material films 121a and 122a. In the example illustrated in <FIG>, the filler enclosed portion <NUM> is in contact with the base material film 122a. In the example illustrated in <FIG>, the filler enclosed portion <NUM> is not in contact with both base material films 121a and 122a. <FIG> illustrates, for the sake of convenience, a state in which two attaching layers 121b which are in contact with the filler enclosed portion <NUM> are separated from each other over the entire range, but these attaching layers 121b may be partially attached to each other.

Here, the filler introducing part <NUM> is formed at an end of the container body-forming sheet member <NUM>, and a non-attached portion <NUM> is also formed in the filler introducing part <NUM>. The filler introducing part <NUM> is a member that introduces the filler into the non-attached portion <NUM>.

Examples of a method of performing the pattern heating include a method of forming a recess (groove) in a portion corresponding to the non-attached portion <NUM> in a die used for heat sealing the film layers <NUM> and <NUM>, and a method of heating the film layers <NUM> and <NUM> while placing a spacer layer having no heat-sealing property in a portion corresponding to the non-attached portion <NUM> between the film layers <NUM> and <NUM>.

The adhesion inhibiting agent may be freely selectable from those capable of inhibiting attaching between the attaching layer 121b and the base material film 122a or attaching between portions of the attaching layer 121b. As the adhesion inhibiting agent, suitable employable are printing inks used for offset printing, flexographic printing and letterpress printing, medium ink, and dedicated adhesion inhibition ink, for example. Also, thermosetting or UV-curable ink can be suitably used.

As illustrated in <FIG> and <FIG>, the film layer <NUM> is formed slightly larger than the film layer <NUM> (excluding the filler introducing part <NUM>), and protrudes around the periphery of the film layer <NUM>. That is, the peripheral edge portion of the container body-forming sheet member <NUM> is formed in an offset shape, and the attaching layer 121b of the film layer <NUM> is exposed. Accordingly, when the peripheral edge portions of the container body-forming sheet member <NUM> are to be attached to each other or the peripheral edge portion of the container body-forming sheet member <NUM> and the inner container-forming sheet member <NUM> are to be attached to each other, the exposed portions of the attaching layer 121b are attached to each other, or the exposed portion of the attaching layer 121b is attached to the inner container-forming sheet member <NUM>. Of course, the film layer <NUM> and the film layer <NUM> may have the same shape. In this case, the portions of the attaching layer 122b of the film layer <NUM> are attached to each other, or the attaching layer 122b is attached to the inner container-forming sheet member <NUM>.

First, as illustrated in <FIG>, <FIG>, and <FIG>, the container body-forming sheet member <NUM> is formed by layering the film layers <NUM> and <NUM> onto each other and partially attaching (for example, heat sealing) the film layers <NUM> and <NUM>. That is, the film layers <NUM> and <NUM> are attached to each other so that a non-attached portion is partially provided between the film layers <NUM> and <NUM>, whereby the non-attached portion <NUM> is formed. Accordingly, in the container body-forming sheet member <NUM>, the film region in which the film layers <NUM> and <NUM> are attached to each other and the non-attached portion <NUM> in which the film layers <NUM> and <NUM> are not attached are formed.

Next, as illustrated in <FIG>, the container body-forming sheet member <NUM> and the inner container-forming sheet member <NUM> are layered onto each other, and are partially attached to each other. In <FIG>, an area where the container body-forming sheet member <NUM> and the inner container-forming sheet member <NUM> are attached to each other is hatched. That is, in the area corresponding to the top gussets <NUM> and <NUM> and the trunks <NUM> and <NUM>, the peripheral edge portions of the inner container-forming sheet member <NUM> and the peripheral edge portions of the container body-forming sheet member <NUM> (that is, portions where the attaching layer 121b of the film layer <NUM> is exposed) are attached (for example, by heat sealing). Here, the inner container-forming sheet member <NUM> and the container body-forming sheet member <NUM> are attached to each other so that in an introducing part-forming part 117a illustrated in <FIG>, the inner container-forming sheet member <NUM> and the container body-forming sheet member <NUM> are not partially attached. This non-attached portion corresponds to the outer air introducing part <NUM>. In this way, the container forming sheet <NUM> formed of the container body-forming sheet member <NUM> and the inner container-forming sheet member <NUM> is formed. Subsequently, the spout <NUM> is provided to the container forming sheet <NUM>. The container forming sheet <NUM> is divided into a top gusset sheet part <NUM>, a top gusset attaching part <NUM>, a main surface sheet part <NUM>, a bottom gusset sheet part <NUM>, a main surface sheet part <NUM>, and a top gusset attaching part <NUM>.

Subsequently, a sheet for container is formed by folding the container forming sheet <NUM> and by attaching the peripheral edge portions of the inner container-forming sheet member <NUM> to each other or the peripheral edge portions of the container body-forming sheet member <NUM> to each other. More specifically, the container forming sheet <NUM> is valley-folded along two folding lines <NUM> and one folding line <NUM>, and mountain-folded at the folding line <NUM> and two folding lines <NUM>.

Here, the two folding lines <NUM> are boundary lines between the bottom gusset sheet part <NUM> and the main surface sheet part <NUM> and between the bottom gusset sheet part <NUM> and the main surface sheet part <NUM>. The folding line <NUM> is a boundary line between the top gusset sheet part <NUM> and the top gusset attaching part <NUM>. The folding line <NUM> is a line passing through a center of the bottom gusset sheet part <NUM>. The folding line <NUM> is a boundary line between the main surface sheet part <NUM> and the top gusset attaching part <NUM>. The valley fold means a way of folding to make a crease protruding toward the far side in <FIG>, whereas the mountain fold means a way of folding to make a crease protruding toward the near side in <FIG>.

In this way, the top gusset sheet part <NUM> overlaps with the top gusset attaching part <NUM> and the top gusset attaching part <NUM>. The main surface sheet parts <NUM> and <NUM> (excluding respective lower end portions) overlap each other, and the lower end portions of the main surface sheet parts <NUM> and <NUM> overlap with the bottom gusset sheet part <NUM>. In this state, the peripheral edge portions are attached.

In this way, the sheet for container is formed. In the sheet for container, the sealed parts <NUM> and <NUM> are formed, and the inner container <NUM> and the container body <NUM> are formed. Subsequently, the filler is introduced into the non-attached portion <NUM> through the filler introducing part <NUM>. As a consequence, the non-attached portion <NUM> expands to form the filler enclosed portion <NUM>. The filler enclosed portion <NUM> provides the rigidity to the container body <NUM>. Then, the filler enclosed portion <NUM> is sealed by sealing a filler injection port in the filler introducing part <NUM>, and then the filler introducing part <NUM> is removed. Furthermore, the content <NUM> is filled into the inner container <NUM> through the spout <NUM>. There is no particular limitation on the temporal relationship between a step of filling the filler into the non-attached portion <NUM> and a step of filling the content <NUM> into the inner container <NUM>. These steps may be performed in any order or at the same time. The sheet material container <NUM> is manufactured through the above-described steps. The spout <NUM> of the sheet material container <NUM> can be sealed by the pumping cap, for example.

Although the sheet material container <NUM> according to the present embodiment has been described above, the sheet material container <NUM> according to the present embodiment is not limited, of course, to the above-described example. For example, the present embodiment is applicable to all of the sheet material containers having a configuration similar to the above-described configuration. Additionally, the sheet material container <NUM> need not include the inner container <NUM> (for example, <FIG> and <FIG>). The present embodiment is also applicable to such a sheet material container <NUM>.

Next, a detailed configuration of the inner container-forming sheet member <NUM> and the container body-forming sheet member <NUM> will be described based on <FIG>. The container body-forming sheet member <NUM> has a layer structure in which the film layers <NUM> and <NUM> are layered onto each other. The film layer <NUM> includes the base material film 121a, and the attaching layer 121b, and the film layer <NUM> includes the base material film 122a, and the attaching layer 122b. The attaching layer 121b attaches the base material films 121a and 122a. Accordingly, it can be also said that the container body-forming sheet member <NUM> has a structure in which a plurality of base material films 121a and 122a are layered.

The base material films 121a and 122a has strength for maintaining the rigidity of the sheet material container <NUM>. That is, as one of the measures to improve the environmental characteristics of the sheet material container <NUM>, the films 121a and 122a are made thin. However, when the base material films 121a and 122a are merely made thin, the strength of the base material films 121a and 122a is reduced, whereby there is a possibility that the rigidity of the sheet material container <NUM> becomes insufficient. As described above, in the present embodiment, the filler enclosed portion <NUM> provides the rigidity to the sheet material container <NUM>, but extremely low strength of the base material films 121a and 122a may cause insufficient rigidity of the sheet material container <NUM>.

In the present embodiment, a tensile modulus of elasticity of the base material films 121a and 122a is preferably not less than <NUM> GPa at a room temperature (= <NUM>). In this way, sufficient rigidity (for example, high compression strength) can be provided to the sheet material container <NUM>. When the tensile modulus of elasticity of the base material films 121a and 122a is not less than <NUM> GPa at the room temperature (= <NUM>), the sufficient rigidity can be provided to the sheet material container <NUM> even if the base material films 121a and 122a are made thinner. That is, the sufficient rigidity can be provided to the sheet material container <NUM> while the resin amount used for the container body-forming sheet member <NUM> is further reduced. The tensile modulus of elasticity of the base material films 121a and 122a is more preferably not less than <NUM> GPa at the room temperature, and even more preferably not less than <NUM> GPa at the room temperature. The tensile modulus of elasticity may be measured according to JIS K <NUM> (Plastics - Determination of tensile properties, Part <NUM>: Test conditions for films and sheets).

Examples of resins of the base material films 121a and 122a satisfying the above-described characteristics are polyester-type resins such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polylactic acid (PLA), and polyhydroxy alkanoate (PHA. The base material films 121a and 122a may be made from any one or more types of these resins. That is, the base material films 121a and 122a may be made from any one (single) type of resin or a blend of two or more types of resins among the resin types listed above. The resins forming the base material films 121a and 122a may contain other additives such as other polymeric materials, fillers (for example, glass, talc, or calcium carbonate), mold release agents, flame retardants, conductive agents, anti-static agents, pigments, antioxidants, impact modifiers, stabilizers, wetting agents, dyes, or any combination thereof.

Furthermore, the base material films 121a and 122a are made from the same type of resins. That is, the attributes of "-type" listed above are common between the base material films 121a and 122a. That is, the base material films 121a and 122a are similar in characteristics (for example, melting points and the like). In particular, it is more preferable that the base material films 121a and 122a are made from resins having the same (common) main skeleton, that is, a single type of resin. In the case where the base material films 121a and 122a are made from a blend of two or more types of resins or a copolymer resin, the phrase "made from the same type of resins" means that the main components are the same type of resins, that is, each base material film contains the same type of resin component or repeating unit in the resin component in an amount of more than <NUM>% by mass, preferably not less than <NUM>% by mass, more preferably not less than <NUM>% by mass, even more preferably not less than <NUM>% by mass, and still more preferably not less than <NUM>%. This enables the base material films 121a and 122a to be easily separated from the sheet material container <NUM> after use (more specifically, from the container body-forming sheet member <NUM>). This is because under an environment in which the base material film 121a can be separated from the container body-forming sheet member <NUM>, the base material film 122a can be also separated at the same time. Accordingly, the recyclability of the sheet material container <NUM> can be improved, and thus the environmental characteristics can be improved. Furthermore, in the case where the base material films 121a and 122a are made from the same and single type of resin, the separated resin is a single type of resin, and therefore becomes a high-quality recycled material. Accordingly, the recyclability of the sheet material container <NUM> is further improved. Each of the base material films 121a and 122a may have a single-layer structure of the same type of resin or a multi-layer structure formed of the same type of resins. In the case where each of the base material films 121a and 122a has a single-layer structure of the same type of resin, there is an advantage that a delamination (layer separation) may not occur in the vicinity of the filler enclosed portion <NUM>.

Printing may be provided on any one or more base material films of the base material films 121a and 122a. In the case where the base material films 121a and 122a are made from the above-described resins, the printing can be clear.

The attaching layers 121b and 122b are layers that provide the sealing property (heat-sealing property) to the container body-forming sheet member <NUM>. From the standpoint of reducing the resin amount used for the container body-forming sheet member <NUM>, it is preferable that the container body-forming sheet member <NUM> is made thinner as much as possible. From this standpoint, it is also conceivable that the film layers <NUM> and <NUM> are formed of only the base material films 121a and 122a. However, in the case where the base material films 121a and 122a have high tensile modulus of elasticity as described above, the sealing property of the base material films 121a and 122a may be insufficient. Therefore, in the present embodiment, the attaching layers 121b and 122b are provided to the film layers <NUM> and <NUM>, and therefore the film layers <NUM> and <NUM> have the sealing property.

The attaching layer 121b is a portion that attaches the portions of the container body-forming sheet member <NUM> (that is, portions of the attaching layer 121b) to each other, that attaches the film layer <NUM> and the film layer <NUM>, and that attaches the container body-forming sheet member <NUM> and the inner container-forming sheet member <NUM> (more specifically, a base material film 110a of the inner container-forming sheet member <NUM>). The filler enclosed portion <NUM> is formed between the base material films 121a and 122a. The filler enclosed portion <NUM> may be in contact with each surface of the base material films 121a and 122a as illustrated in <FIG>, and may be in contact with one base material film (in this example, the base material film 122a) as illustrated in <FIG>. As illustrated in <FIG>, the attaching layers 121b may be formed on the surfaces facing each other of the base material films 121a and 122a, respectively, and the filler enclosed portion <NUM> may be in contact with the two attaching layers 121b. In <FIG> and <FIG>, the inner container-forming sheet member <NUM> is not shown.

As described above, the attaching layer 122b is a portion that attaches the portions of the container body-forming sheet member <NUM> (that is, portions of the attaching layer 122b) to each other, and that attaches the container body-forming sheet member <NUM> and the inner container-forming sheet member <NUM>. However, in the case where the film layer <NUM> is formed slightly larger than the film layer <NUM>, the attaching layer 121b is used to attach the portions of the container body-forming sheet member <NUM> to each other and attach the container body-forming sheet member <NUM> and the inner container-forming sheet member <NUM>. Accordingly, in this case, the attaching layer 122b is not necessarily required.

Furthermore, it is preferable that the melting point of the base material films 121a and 122a is different from that of the attaching layers 121b and 122b. In this case, using the difference in melting point between the base material films 121a and 122a and the attaching layers 121b and 122b, the base material films 121a and 122a can be easily separated from the container body-forming sheet member <NUM>. The melting point of the base material films 121a and 122a is preferably higher than that of the attaching layers 121b and 122b, and the difference in melting point is preferably not less than <NUM>, and more preferably not less than <NUM>. An upper limit of the difference in melting point may be any value, but may be about <NUM>.

Examples of resins (attaching agents) of the attaching layers 121b and 122b satisfying the above-described characteristics include known adhesive compositions such as an urethane-based adhesive composition, a vinyl-based adhesive composition such as vinyl acetate, vinyl alcohol, and ethylene vinyl acetate, a modified olefin-based adhesive composition, a (meta)acrylic-based adhesive composition containing butyl acrylate, <NUM>-ethylhexyl methacrylate and the like as a main component, a polyamide-based adhesive composition, a polyester-based adhesive composition, a silicone-based adhesive composition, and a rubber-based adhesive composition containing, as main components, natural rubber and/or synthetic rubber such as isoprene rubber, butadiene-styrene-rubber, and acrylic rubber. The attaching layers 121b and 122b may be made from any one or more types of these resins. Similar to the base material films described above, the resins forming the attaching layers 121b and 122b are the same type of resins as the base material films 121a and 122a. In this case, the affinity between the attaching layers 121b and 122b and the base material films 121a and 122a are enhanced, whereby the sealing property is improved. Furthermore, even if some attaching agent remains on the base material films 121a and 122a at the time of recycling of the base material films 121a and 122a, it is unlikely to affect the quality of the recycled material. Of course, the resins forming the attaching layers 121b and 122b may be of different types.

It is preferable that the total thickness of the base material films 121a and 122a has a range of ratios with respect to the thickness of the attaching layer 121b (that is, a attaching layer attaching the base material films 121a and 122a to each other). Specifically, the ratio (B/A) of the total thickness B of the base material films 121a and 122a with respect to the thickness A of the attaching layer 121b is preferably larger than <NUM>. In this way, the thickness of the attaching layer 121b can be reduced, whereby the resin amount used can be reduced, and furthermore the resins of the base material films 121a and 122a can be easily separated from the sheet material container <NUM>. The "B/A" is more preferably not smaller than <NUM>, and even more preferably not smaller than <NUM>. An upper limit of the "B/A" may be any value. However, when the "B/A" is too high, it may cause the total thickness of the film layers <NUM> and <NUM> to be increased excessively. Therefore, the "B/A" is preferably not larger than <NUM>, more preferably not larger than <NUM>, even more preferably not larger than <NUM>, still more preferably not larger than <NUM>, and further more preferably not larger than <NUM>.

From the standpoint of improving the environmental characteristics, each thickness of the base material films 121a and 122a is preferably not more than <NUM>, more preferably not more than <NUM>, and even preferably not more than <NUM>. However, when each thickness of the base material films 121a and 122a is too small, the base material films 121a and 122a tend not to withstand the internal pressure required to sufficiently maintain the container rigidity when the filler is enclosed in the filler enclosed portion <NUM>. Therefore, the thickness is preferably not less than <NUM>, more preferably not less than <NUM>, and even preferably not less than <NUM>.

The thickness of the attaching layer 121b is preferably not more than <NUM>, and more preferably not more than <NUM>. The thickness of the attaching layer 121b is preferably not less than <NUM>. In this case, the thickness of the container body-forming sheet member <NUM> can be reduced and the recyclability of the container body-forming sheet member <NUM> can be improved, while maintaining the rigidity of the sheet material container <NUM>.

For the same reason, the thickness of the attaching layer 122b is also preferably not more than <NUM>, and more preferably not more than <NUM>. The thickness of the attaching layer 122b is preferably not less than <NUM>.

Additionally, the container body-forming sheet member <NUM> may have the multi-layer structure including three or more layers. In this case, since the base material films are formed in three or more layers, the attaching layers that attach the base material films to each other are formed in two or more layers. In this case, a value "A" in the above-described "B/A" is rephrased as the total thickness of the attaching layers that attach the base material films to each other, and the thickness of the attaching layer 121b is rephrased as the total thickness of the attaching layers that attach the base material films to each other.

Next, a detailed configuration of the inner container-forming sheet member <NUM> will be described based on <FIG>. The inner container-forming sheet member <NUM> according to the present embodiment includes the base material film 110a and an attaching layer 110b. The resin of the base material film 110a may be any resin, and may be of the same type as or different type from the base material films 121a and 122a. In the case where the resin of the base material film 110a is of the same type as the base material films 121a and 122a, a tensile modulus of elasticity of the base material film 110a is preferably not less than <NUM> GPa at a room temperature (= <NUM>). Examples of other type of resin include oriented nylon and the like.

The attaching layer 110b is a layer that provides the sealing property to the inner container-forming sheet member <NUM>. Specifically, the attaching layer 110b is used for attaching portions of the inner container-forming sheet member <NUM> to each other. The resin forming the attaching layer 110b may be any resin, and may be of the same type as or different type from the attaching layers 121b and 122b. Examples of other type of resin include linear low-density polyethylene (LLDPE) and the like.

As in the embodiment illustrated in <FIG>, in the embodiment in which the inner container-forming sheet member <NUM> (the sheet member of the top gusset <NUM>) and the base part <NUM> of the spout <NUM> are attached to each other, it is more preferable that the spout <NUM> provided with the base part <NUM> is made from the same type of resin as the base material film 110a and/or the attaching layer 110b of the inner container-forming sheet member <NUM> in a manner similar to the base material films described above, because the recyclability can be improved. Additionally, as in the embodiment illustrated in <FIG> and <FIG>, in the case of the embodiment in which the base part <NUM> of the spout <NUM> is attached to the container body-forming sheet member <NUM> (the sheet member of the top gusset <NUM>), the spout <NUM> provided with the base part <NUM> may be made from resins of the same type as one or more resins selected from the resins of the base material films 121a and 122a and the attaching layers 121b and 122b of the container body-forming sheet member <NUM>.

From the standpoint of the environmental characteristics, it is preferable that the base material film 110a is made thinner as much as possible. For example, the thickness of the base material film 110a is preferably not more than <NUM>, and more preferably not more than <NUM>. A lower limit of the thickness of the base material film 110a may be any value that can maintain the rigidity as the inner container <NUM>. For example, the thickness of the base material film 110a may be not less than <NUM>.

From the standpoint of the environmental characteristics, it is also preferable that the attaching layer 110b is made thinner as much as possible. For example, the thickness of the attaching layer 110b is preferably not more than <NUM>, and more preferably not more than <NUM>. A lower limit of the thickness of the attaching layer 110b may be any value that can maintain the rigidity and the sealing property as the inner container <NUM>. For example, the thickness of the attaching layer 110b may be not less than <NUM>.

Additionally, the layer structure of the inner container-forming sheet member <NUM> is not limited to the above-described example. For example, the inner container-forming sheet member <NUM> may have the layer structure disclosed in <CIT>. However, from the standpoint of the environmental characteristics, it is preferable that the inner container-forming sheet member <NUM> has the above-described layer structure.

As described above, according to the present embodiment, the base material films 121a and 122a are made from the same type of resins, whereby the recyclability can be improved. Furthermore, when the tensile modulus of elasticity of the base material films 121a and 122a is not less than <NUM> GPa at the room temperature, the sufficient rigidity can be provided to the sheet material container <NUM>. Therefore, according to the present embodiment, the recyclability can be further improved while maintaining a function of the sheet material container <NUM>. Additionally, when the tensile modulus of elasticity of the base material films 121a and 122a is not less than <NUM> GPa, the sufficient rigidity can be provided to the sheet material container <NUM> even if the base material films 121a and 122a are made thinner. Accordingly, since the resin amount used can be reduced, the environmental characteristics can be further improved.

In Examples <NUM> to <NUM>, PET films having thicknesses different from one another were prepared as the base material films 121a and 122a. Also, polyester-based attaching agents (manufactured by TOAGOSEI CO. ) were prepared as the attaching agents forming the attaching layers 121b and 122b. Furthermore, in Example <NUM>, nylon films were prepared as the base material films 121a and 122a, and polyethylene films (LLDPE) were prepared as the attaching layers 121b and 122b.

The environmental characteristics of Examples <NUM> to <NUM> (specifically, thickness reduction and recyclability) were evaluated by the following tests. First, in each of Examples <NUM> to <NUM>, a sheet member for test was manufactured in which the base material films 121a and 122a were attached by the above-described attaching layer 121b. The pressure and temperature at the time of attaching were common among all examples and comparative examples described later. The sheet member for test included the base material films 121a and 122a and the attaching layer 121b. The thickness of the base material films 121a and 122a and the attaching layer 121b was changed for each example. In Example <NUM>, the base material films 121a and 122a and two attaching layers 121b were attached by dry lamination, and a sheet member for test was manufactured, including the filler enclosed portion <NUM> between the two attaching layers 121b, as illustrated in <FIG>.

Next, the thickness of the sheet member for test was measured. A sheet member (PET12 / aluminum-deposited PET12 / NY15 / LLDPE70) of a commercially available pouch having no filler enclosed portion was used as a reference sample. The thickness (<NUM>) of the reference sample was regarded as <NUM>, and a ratio of the thickness of the sheet member for test in each of Examples <NUM> to <NUM> with respect to the reference sample was used as an evaluation index of thickness reduction. A ratio value of <NUM> or less is an acceptable level in view of evaluation of the thickness reduction, and the ratio value is preferably not more than <NUM>. Additionally, the "B/A" was calculated.

Furthermore, evaluation of the recyclability was performed using the sheet member for test. Specifically, the heat was applied to the entire surface of the sheet member for test at <NUM> and <NUM> MPa for <NUM> sec. , and then it was confirmed whether the base material films 121a and 122a were easily separated from the sheet member for test manually. In the case where the base material film 121a is easily separated from the sheet member for test manually, the recyclability is evaluated at a level <NUM> or higher. In the case where the base material film 121a is not easily separated from the sheet member for test, the recyclability is evaluated at a level <NUM> when the base material films 121a and 122a are made from the same type of resins, and the recyclability is evaluated at a level <NUM> when the base material films 121a and 122a are made from different (different types of) resins. The level <NUM> is regarded as unacceptable, and the level <NUM> or higher is regarded as acceptable. This is because it is preferable that the base material films 121a and 122a can be easily separated from the attaching layer 121b manually, from the standpoint of the recyclability.

With respect to the sheet members for test in which the recyclability was evaluated at the level <NUM> or higher, the following tests were further performed. First, the mass of the base material films 121a and 122a only were measured, and then the mass of the sheet members for test was measured, in which the base material films 121a and 122a were attached by the attaching layer 121b. Then, the mass of the attaching layer 121b before cleaning was calculated based on the difference between the measured masses. Subsequently, the base material films 121a and 122a were immersed in acetone (cleaning solution) and stirred for <NUM> hours. In this test, the acetone was used, but a known alkaline cleaning solution including an alkaline aqueous solution such as caustic soda or a general organic solvent such as ethanol may be used as the cleaning solution. Then, the base material films 121a and 122a were taken out of the acetone, washed with water, and dried. Subsequently, the mass of the base material films 121a and 122a after the drying was measured. The mass of remaining attaching layer 121b was calculated by subtracting, from the measured mass, the initial measured mass of the base material films 121a and 122a. The remaining ratio was calculated by the following formula: (the mass of the remaining attaching layer / the initial mass of the attaching layer) × <NUM>. When the remaining ratio is not more than <NUM>%, the recyclability is evaluated at a level <NUM>. When the remaining ratio exceeds <NUM>%, the recyclability is evaluated at a level <NUM>. Lower remaining ratio of the attaching layer 121b means that a larger amount of pure PET was able to be recovered, and therefore the recyclability is high. The sample with the evaluation level <NUM> was stirred in the acetone for further <NUM> hours, and the remaining ratio of <NUM>% or less was obtained.

The film layers <NUM> and <NUM> were manufactured using the above-described base material films 121a and 122a and attaching layers 121b and 122b. Here, the thickness of the base material films 121a and 122a and the thickness of the attaching layers 121b and 122b were the same as the thickness of the base material films 121a and 122a and the thickness of the attaching layer 121b in the sheet member for test. Furthermore, as the inner container-forming sheet member <NUM>, an inner container-forming sheet member <NUM> similar to that of Comparative Example <NUM> (which will be described later) was prepared. Then, a sheet material container <NUM> was manufactured according to the above-described manufacturing method. Here, all of the manufacturing conditions of the sheet material container <NUM> (shapes of the film layers <NUM> and <NUM>, a shape of the filler enclosed portion <NUM>, a type of the filler, an internal pressure of the filler enclosed portion, a sealing pressure, a sealing temperature, widths of the sealed parts <NUM> and <NUM>, and the like) were the same as the above-described manufacturing conditions. That is, the sheet material containers <NUM> of Examples <NUM> to <NUM> are different only in the layer structures of the film layers <NUM> and <NUM> (specifically, a thickness and a material of each layer).

Then, the manufactured sheet material container <NUM> was set to a compression tester. The compression tester includes two upper and lower compression plates, a compressor that compresses the sheet material container <NUM> using these compression plates, and a measuring device that measures a stress at the time of compression. Then, the sheet material container <NUM> was compressed using the compression plates. The compression was performed under the environment of <NUM> and <NUM>% RH. The compression speed was set to <NUM>/min. Then, the stress was read when the height of the sheet material container <NUM> was compressed to <NUM>/<NUM> of the initial height, and was compared with a stress of Comparative Example <NUM> described later. The container rigidity was evaluated according to the following evaluation criteria. A level <NUM> or lower are regarded as acceptable in view of evaluation of the container rigidity, and means that the container has an anti-compression strength enough to withstand use (pumping or the like) as a container.

First, the layer configuration of the sheet member used in each of Comparative Examples <NUM> to <NUM> will be described based on <FIG>. A container body-forming sheet member <NUM> used in each of Comparative Examples <NUM> to <NUM> includes film layers <NUM> and <NUM>. The film layer <NUM> is a layer corresponding to the film layer <NUM> of the present embodiment, and includes a base material film 221c and an attaching layer 221f. The film layer <NUM> is a layer corresponding to the film layer <NUM> of the present embodiment, and includes an attaching layer 222c, a base material film 222d and an attaching layer 222e.

It can be said that attaching layers 221f and 222c correspond to the attaching layer 121b of the present embodiment, and an attaching layer 222e corresponds to the attaching layer 122b of the present embodiment. A filler enclosed portion <NUM> is formed between the base material films 221c and 222d. An inner container-forming sheet member <NUM> includes an attaching layer 210c, a base material film 210d, and an attaching layer 210e.

In each of Comparative Examples <NUM> to <NUM>, all of the attaching layers included in the inner container-forming sheet member <NUM> and the container body-forming sheet member <NUM> are made from LLDPE. In Comparative Example <NUM>, the base material film 221c had a three-layer structure including a PET layer, a transparent vapor deposited PET layer, and a nylon layer laminated in order from the surface. In Comparative Example <NUM>, the base material film 221c had a two-layer structure including a transparent vapor deposited PET layer, and a nylon layer laminated in order from the surface. In Comparative Example <NUM>, the base material film 221c had a single-layer structure including a transparent vapor deposited PET layer from the surface. In all of Comparative Examples <NUM> to <NUM>, the base material films 222d and 210d were made from oriented nylon.

The base material film 221c in which the attaching layer 221f was formed on a surface thereof and the base material film 222d in which the attaching layer 222c was formed on a surface thereof were prepared, and the base material films 221c and 222d overlapped each other so that the respective attaching layers faced each other. The thickness of the base material films 221c and 222d and the attaching layers 221f and 222c was set to be different among Comparative Examples <NUM> to <NUM>. Then, the multilayer was pressurized at the same pressure and temperature as those of Examples <NUM> to <NUM>. In this way, a sheet member for test was manufactured. Then, the thickness reduction and the recyclability were evaluated by the tests similar to those of Examples <NUM> to <NUM>. Additionally, the "B/A" was calculated. Here, "A" refers to the total thickness of the attaching layers 221f and 222c.

A sheet material container was manufactured using the container body-forming sheet member <NUM> and the inner container-forming sheet member <NUM>. Here, the thickness of the base material films 221c and 222d and the thickness of the attaching layers 221f and 222c were the same as the thickness of the base material films 221c and 222d and the thickness of the attaching layers 221f and 222c in the sheet member for test. The thickness of the attaching layer 222e was set to <NUM>, and the thicknesses of the attaching layer 210c, the base material film 210d, and the attaching layer 210e were set to <NUM>, <NUM>, and <NUM>, respectively. Then, a sheet material container was manufactured according to the above-described manufacturing method. Here, all of the manufacturing conditions of the sheet material container were the same as those of Examples <NUM> to <NUM>. That is, the sheet material containers of Comparative Examples <NUM> to <NUM> are different only in the layer structures (specifically, a thickness of each layer and resin types) of the film layers <NUM> and <NUM> from the sheet material containers of Examples <NUM> to <NUM>. Then, the container rigidity was evaluated by the tests similar to those of Examples <NUM> to <NUM>.

The layer configurations (layer configuration of the sheet member for test) and evaluation results of Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM>, and the tensile moduluses of elasticity of the base material films 121a and 122a made from the same type of resins of Examples <NUM> to <NUM> that were measured at the room temperature (= <NUM>) according to JIS K <NUM> (Plastics - Determination of tensile properties, Part <NUM>: Test conditions for films and sheets) are summarized in Tables <NUM> to <NUM>.

In Examples <NUM> to <NUM> having the layer configuration corresponding to the container body-forming sheet member <NUM> of the present embodiment, all values of the recyclability achieved the acceptable level of <NUM> or higher. Furthermore, all value of the container rigidity also achieved the acceptable level of <NUM> or lower. Accordingly, the recyclability can be improved while maintaining a function of the sheet material container <NUM>. On the other hand, in all of Comparative Examples <NUM> to <NUM>, the results of the recyclability became inferior (the evaluation level was <NUM>). In Comparative Examples <NUM> to <NUM>, it is believed that the recyclability was reduced because the attaching layer could not be easily separated from the base material film even at the same temperature as the Examples <NUM> to <NUM>, and a component derived from the attaching layer could not be sufficiently removed even after the cleaning operation was performed.

From the results of Examples <NUM> to <NUM>, it has been found that the container rigidity and the environmental characteristics (in particular, thickness reduction) are basically in a tradeoff relationship. That is, when the thickness of the base material films 121a and 122a and the attaching layer 121b is increased, the container rigidity is increased, but the environmental characteristics tend to be reduced. However, it has been found that when the thickness of the attaching layer 121b becomes too large relative to the thickness of the base material films 121a and 122a, the container rigidity is slightly reduced. This reason is unclear, however, it is believed that since the attaching layer 121b is soft, the container body-forming sheet member <NUM> is more flexible by increasing the thickness of the attaching layer 121b relative to the base material films 121a and 122a.

Upon reviewing the results in more detail, in Examples <NUM> to <NUM>, and <NUM> in which the thickness of the attaching layer 121b is not more than <NUM>, the results of at least one of the thickness reduction and the container rigidity was further improved as compared with Examples <NUM> to <NUM> in which the thickness of the attaching layer 121b exceeds <NUM>. Accordingly, it has been found that the thickness of the attaching layer 121b is preferably not more than <NUM>.

Next, upon reviewing Examples <NUM> to <NUM> and <NUM>, it has been found that in Examples <NUM> to <NUM> in which the thickness of the attaching layer 121b is not more than <NUM>, the recyclability is further improved as compared with Examples <NUM> to <NUM> and <NUM> in which the thickness of the attaching layer 121b exceeds <NUM>. Accordingly, it has been found that the thickness of the attaching layer 121b is more preferably not more than <NUM>.

Next, upon reviewing Examples <NUM> to <NUM>, in Examples <NUM> to <NUM> in which the thickness of the attaching layer 121b is not less than <NUM> and the "B/A" is larger than <NUM>, the container rigidity was further improved and stabilized as compared with Examples <NUM> to <NUM> in which the thickness of the attaching layer 121b is less than <NUM>. That is, in Examples <NUM> to <NUM>, since the attaching layer 121b was thin, it caused variations in the results of the container rigidity. Meanwhile, in Examples <NUM> to <NUM> in which the thickness of the attaching layer 121b is not less than <NUM> and the "B/A" is larger than <NUM>, the results of the container rigidity were stably evaluated at a level <NUM> or lower. Accordingly, it has been found that the thickness of the attaching layer 121b is more preferably not less than <NUM>. Furthermore, it has been found that the "B/A" is preferably larger than <NUM>.

Claim 1:
A sheet material container (<NUM>), comprising:
a container body (<NUM>) that surrounds a containing portion for accommodating a content (<NUM>),
wherein the container body (<NUM>) is formed of a container body-forming sheet member (<NUM>) formed by layering a plurality of base material films (121a, 122a),
the container body-forming sheet member (<NUM>) includes the plurality of base material films (121a, 122a), an attaching layer (121b) by which the base material films (121a, 121b) are attached to each other, and a filler enclosed portion (<NUM>) that is formed between the plurality of base material films (121a, 122a) and into which a filler is to be filled, and
the plurality of base material films (121a, 122a) are made from the same type of resins,
the plurality of base material films (121a, 122a) and the attaching layer (121b) are made from the same type of resins, and
characterized in that
the same type of resins are polyester-type resins, and
the attaching layer (121b) is formed, to which an attaching agent is applied.