Pouch with spout, multilayer film, and manufacturing method of pouch with spout

Abstract

To provide a pouch with a spout, which is excellent in low adsorptivity, and joining strength of a seal portion between the pouch and the spout.SOLUTION: In a multilayer film used for a pouch with a spout, the multilayer film comprises a base material layer and a sealant layer disposed on one surface of the base material layer. The sealant layer includes a first polyolefin layer which is disposed on an outermost surface on a side opposite to the base material layer and contains a polyolefin-based resin as a principal component, a low-adsorption layer which is disposed on the base material layer side of the first polyolefin layer and contains a low-adsorptive resin as a principal component, and a second polyolefin layer which is disposed on the base material layer side of the low-adsorption layer and contains a polyolefin-based resin as a principal component, in which a thickness of the second polyolefin layer is larger than a thickness of the first polyolefin layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a spouted pouch, a multilayer film, and a method for manufacturing a spouted pouch. [Background technology]

[0002] Patent Document 1 discloses a multilayer film used for packaging bags such as stand-up pouches. This multilayer film includes a layer (sealing layer) on the outermost surface (the innermost surface of the packaging bag) that contains as its main component a polyolefin resin with heat sealing properties, and a layer (low adsorption layer) laminated thereon that contains as its main component a low adsorption resin. It is also described that a layer containing a polyolefin resin as a main component may be further laminated on the low adsorption layer (on the surface opposite to the seal layer).

[0003] Polyolefin resins can easily achieve high seal strength through heat sealing, but they also tend to adsorb organic compounds, etc. As a result, active ingredients contained in the contents of the packaging bag, such as vitamins, medicinal ingredients, fragrances, and coloring agents, can be adsorbed into the sealing layer, potentially causing problems such as a decrease in the content or change in composition of the active ingredients, or deterioration or discoloration of the packaging bag. By laminating a low-adsorption layer that has low adsorption of organic compounds and the like onto the sealing layer and reducing the thickness of the outermost (innermost) polyolefin layer, a multilayer film is provided that is heat-sealable yet does not easily adsorb the contents of a packaging bag.

[0004] On the other hand, pouches with spouts into which beverages, foods, medicines, shampoos, detergents, etc. are filled are known (see, for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2016 / 021682 [Patent Document 2] International Publication No. 2005 / 102855 [Patent Document 3] International Publication No. 2022 / 215625 Summary of the Invention [Problem to be solved by the invention]

[0006] It is desirable to thin the innermost seal layer in order to reduce the amount of adsorption of organic compounds, etc. However, thinning the seal layer reduces the seal strength, and in the case of spouted pouches, the seal area between the spout and the multilayer film is a joint made of materials with different properties, which makes this area particularly prone to rupture and peeling.

[0007] An object of the present invention is to provide a spouted pouch that has excellent low adsorption properties and excellent bonding strength at the seal portion with the spout. [Means for solving the problem]

[0008] The spouted pouch of the present invention comprises: A spout-equipped pouch comprising a pouch made of a multilayer film and a spout attached to the pouch, The multilayer film includes a base layer and a sealant layer provided on one surface of the base layer, The sealant layer comprises: a first polyolefin layer provided on the outermost surface opposite to the base layer and containing a polyolefin resin as a main component; a low adsorption layer provided on the base layer side of the first polyolefin layer and containing a low adsorption resin as a main component; a second polyolefin layer provided on the substrate layer side of the low adsorption layer and containing a polyolefin resin as a main component; the thickness of the second polyolefin layer is greater than the thickness of the first polyolefin layer; A resin pool is formed in the multilayer film on the edge side of the attachment portion of the spout.

[0009] The multilayer film of the present invention is a multilayer film used for a pouch with a spout, A substrate layer and a sealant layer provided on one surface of the substrate layer, The sealant layer comprises: a first polyolefin layer provided on the outermost surface opposite to the base layer and containing a polyolefin resin as a main component; a low adsorption layer provided on the base layer side of the first polyolefin layer and containing a low adsorption resin as a main component; a second polyolefin layer provided on the substrate layer side of the low adsorption layer and containing a polyolefin resin as a main component; The second polyolefin layer has a thickness greater than the thickness of the first polyolefin layer. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a spouted pouch that has excellent low adsorption properties and excellent bonding strength at the seal portion with the spout. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a multilayer film of an embodiment. [Figure 2] FIG. 1 is a perspective view showing an example of a pouch with a boat-shaped spout. [Figure 3] FIG. 3 is a side view of the pouch with a boat-shaped spout shown in FIG. 2. [Figure 4] FIG. 1 is a perspective view showing an example of a pouch with a flanged spout. [Figure 5] FIG. 5 is a cross-sectional view of the flanged spout pouch shown in FIG. 4 taken along the line AA. [Figure 6] 1A and 1B are diagrams showing the state of the portion of a pouch with a boat-shaped spout where the spout and the multilayer film are welded together before welding, where (a) is a perspective cross-sectional view and (b) is a cross-sectional view. [Figure 7]6A and 6B are longitudinal cross-sectional views showing the state of the portion of the pouch with a boat-shaped spout where the spout and the multilayer film are to be welded together before welding, where (a) is a cross-sectional view taken along the XX plane in FIG. 6 and (b) is a cross-sectional view taken along the YY plane in FIG. 6. [Figure 8] 2 is a cross-sectional perspective view (cross-sectional view and perspective view on plane XX) showing the state of the welded portion between the spout and the multilayer film in a pouch with a boat-shaped spout. FIG. [Figure 9] 8A and 8B are longitudinal cross-sectional views showing the state of the welded portion between the spout and the multilayer film in a pouch with a boat-shaped spout, where (a) is a cross-sectional view taken along the XX plane in FIG. 8 and (b) is a cross-sectional view taken along the YY plane in FIG. 8. [Figure 10] 9(b) is a longitudinal cross-sectional view (corresponding to FIG. 9(b)) showing the state after welding of the spout and the multilayer film in another example of a pouch with a boat-shaped spout. FIG. [Figure 11] 1A and 1B are diagrams showing an example of a sealing process for an example of a pouch with a flanged spout, where (a) is a cross-sectional view showing a heat-sealing process, and (b) is a cross-sectional view showing a cool-sealing process. [Figure 12] 1A and 1B are diagrams showing a modified example of the sealing process for an example of a pouch with a flanged spout, where (a) is a cross-sectional view showing the heat-sealing process, and (b) is a cross-sectional view showing the cool-sealing process. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings, in which the same or common parts are designated by the same reference numerals.

[0013] The spouted pouch 6 of this embodiment includes a pouch 61 made of the multilayer film 1, and a spout 4 attached to the pouch 61 (see FIGS. 2 to 5). Spouted pouches are used to package liquid, powder, granular, and other products such as beverages, food, medicines, shampoos, and detergents. The multilayer film 1 of this embodiment is used for a spouted pouch 6. That is, the multilayer film 1 is used as a material for the pouch 61 portion of the spouted pouch 6.

[0014] (pouch with spout) 2 to 5, examples of pouches with spouts are shown. The spouted pouch 6 is composed of a pouch 61 formed by the multilayer film 1 and a spout 4 attached to the pouch 61.

[0015] The spout-equipped pouch 6 (boat-shaped spout-equipped pouch) shown in FIGS. 2 and 3 is composed of a pouch 61 formed by the multilayer film 1 and a spout 4 attached to the pouch 61. The pouch 61 is formed by heat-sealing the peripheral edge 10 of the multilayer film 1, and has a body portion (side surface) and a bottom gusset portion. The spout 4 is composed of a mouth body 40 having a communicating hole for pouring out liquid products or the like filled in the pouch 61, and a boat-shaped (see Figure 6) or elliptical mounting portion 41 (boat-shaped mounting portion) having a communicating hole connected to the mouth body 40 and a thin cross-sectional shape (thin-walled portion 41b) formed on both ends. A screw-type cap 43 is fitted to the mouth body 40 so as to be openable and closable. The spout 4 (mouth body 40 and attachment part 41) is formed by injection molding or the like, and the attachment part 41 is formed from a polyolefin resin that can be heat-sealed with the sealing layer of the multilayer film described below. The spout 4 is attached to the pouch 61 by heat-sealing the attachment portion 41 while it is sandwiched between the multilayer films 1 that form the pouch 61 .

[0016] The spout pouch 6 (flange-type spout pouch) shown in Figs. 4 and 5 differs from the pouch with a boat-shaped spout in the shape of the attachment portion 42 (flange-type attachment portion) of the spout 4. The mounting portion 42 is a flat flange portion (flange-shaped mounting portion) that is continuously provided from the outer periphery of the mouth body 40 toward the outside.

[0017] The shape of the flange-type mounting portion (mounting portion 42) (the shape in a plan view seen from the thickness direction of the flange-type mounting portion) is, for example, circular, rectangular, polygonal, or the like. The thickness of the flange-type mounting portion is, for example, 0.5 to 2 mm. The mounting portion 42 (flange-shaped mounting portion) is formed by injection molding together with the mouth body 40, similar to the boat-shaped mounting portion described above, and is made of a polyolefin-based resin that can be heat-sealed with the sealing layer of the multi-layer film described below.

[0018] The multilayer film 1 constituting the pouch 61 is heat-sealed to one surface of the attachment portion 42 . The pouch 61 includes a top gusset portion 61 a, a body portion 61 b, and a bottom gusset portion 61 c, and the multilayer film that forms the top gusset portion 61 a is heat-sealed to the upper surface of the attachment portion 41 .

[0019] <Multilayer film> Referring to FIG. 1, a multilayer film 1 of the present embodiment includes a base layer 2 and a sealant layer 3 provided on one surface of the base layer 2. The sealant layer 3 includes a first polyolefin layer 31 , a low-adsorption layer 32 , and a second polyolefin layer 33 . The first polyolefin layer 31 (sealing layer) is provided on the outermost surface opposite to the base layer 2, and contains a polyolefin resin as a main component. The low adsorption layer 32 is provided on the base layer 2 side of the first polyolefin layer 31, and contains a low adsorption resin as a main component. The second polyolefin layer 33 is provided on the base layer 2 side of the low adsorption layer 32 of the sealant layer 3, and contains a polyolefin resin as a main component. The thickness of the second polyolefin layer 33 is greater than the thickness of the first polyolefin layer 31 .

[0020] The multilayer film 1 of the present invention has excellent low adsorption properties (i.e., the contents of the packaging bag are less likely to be adsorbed) because the first polyolefin layer 31 (sealing layer), which is the innermost layer (the layer that comes into contact with the contents of the packaging bag), is thin. Furthermore, in the multilayer film 1 of the present invention, the second polyolefin layer 33, which is laminated on the outside (outside the packaging bag) of the low adsorption layer 32, is thicker, so when the multilayer film 1 is heat-sealed to the spout 4, the resin that makes up the second polyolefin layer 33 softens or melts and flows at a larger rate, and the low adsorption layer 32 and the first polyolefin layer 31 (sealing layer) also flow in response, forming a resin puddle 3a that covers part (or all) of the edges 41a, 42a of the attachment parts 41, 42 of the spout 4 (the parts that are attached to the pouch 61) (see Figures 9 to 11). In this manner, resin pools 3a are formed in the multilayer film 1 on the side of the end edges 41a, 42a of the attachment portions 41, 42 of the spout 4.

[0021] 9 and 10 is the edge on the storage section side (content side) of pouch 61. When pouch 61 is subjected to an impact, a load is likely to be applied from the storage section side to peel the seal between the spout and the multilayer film, so the seal strength of this storage section side, strengthened by resin pool 3a, is particularly effective in preventing rupture or peeling of the seal. Resin pool 3a increases the bonding strength between spout 4 and multilayer film 1, improving the seal strength between spout 4 and multilayer film 1 and particularly improving strength against peeling due to stress from the storage section side of pouch 61, which is a likely cause of breakage. In this way, even when the thickness of the first polyolefin layer 31 is reduced, the sealing strength of the multilayer film 1 to the spout 4 can be increased.

[0022] Hereinafter, each layer constituting the multilayer film 1 of this embodiment will be described in detail.

[0023] [Base material layer] The material constituting the base layer 2 is not particularly limited, but examples thereof include resin film, cellophane, paper, paperboard, textile, aluminum foil, etc. The material constituting the surface of the base layer 2 opposite to the sealant layer 3 is preferably heat resistant. Examples of resin films include polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyolefin resins such as polypropylene resin and polyethylene resin. When a resin film is used as the base layer 2, the resin film may be stretched or unstretched. A resin film that has been stretched (stretched and then heat-set) has superior heat resistance, dimensional stability, and rigidity compared to an unstretched resin film. Examples of stretched films include biaxially stretched polyethylene terephthalate films and biaxially stretched nylon films. When a polyolefin monomaterial is required as an easily recyclable structure, a single layer or multiple layers of a film made of biaxially or uniaxially stretched polyethylene resin or polypropylene resin can also be used.

[0024] The substrate layer 2 may be a single layer or a multilayer. The multi-layer substrate layer 2 may be a substrate layer formed by laminating a barrier layer that prevents permeation of oxygen gas, water vapor, etc., a reinforcing layer, etc., on a resin film.

[0025] Examples of the barrier layer include a vapor-deposited layer of an inorganic oxide such as silicon oxide or aluminum oxide, a layer made of a film having such a vapor-deposited layer, a polyvinylidene chloride resin layer, a vinyl alcohol resin layer, an ethylene-vinyl alcohol copolymer layer, a polyacrylonitrile resin layer, a polyamide resin layer, etc. From the viewpoint of barrier performance, it is preferable to use a vapor-deposited layer of an inorganic oxide such as silicon oxide or aluminum oxide as the barrier layer.

[0026] The thickness of the base layer 2 is not particularly limited, but is preferably 10 to 100 μm, and more preferably 10 to 60 μm.

[0027] Various designs and display items may be printed on the base material layer 2. For printing, known methods such as gravure printing and flexographic printing can be used.

[0028] [Sealant layer] The sealant layer 3 includes a first polyolefin layer 31 , a low-adsorption layer 32 , and a second polyolefin layer 33 .

[0029] The sealant layer 3 and the base layer 2 may be laminated by known methods such as dry lamination, wet lamination, sand lamination, and hot melt lamination.

[0030] The sealant layer 3 and the base layer 2 may be laminated together either without or with an adhesive. Examples of adhesives used to bond the sealant layer 3 and the base layer 2 include solvent-based, solventless, and aqueous emulsion-based adhesives such as two-component curing polyurethane adhesives, epoxy adhesives, and acid-modified olefin resin adhesives. Furthermore, each layer may be appropriately subjected to a primer treatment, anchor coat treatment, or the like. When the sandwich lamination method is used as the lamination method, it is preferable to use a polyethylene resin as the extruded resin to be sandwiched, because the extruded resin softens or melts together with the polyolefin layer of the sealant layer during heat sealing.

[0031] (First polyolefin layer: sealing layer) The first polyolefin layer 31 (sealing layer) contains a polyolefin resin as a main component.

[0032] In this specification, the term "main component" refers to a component that accounts for 50% by mass or more of the total amount. The content of the main component is preferably 70% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and more preferably 98% by mass or more. Furthermore, it is preferable that the entire amount is substantially composed of only the main component. Note that components other than the main component may be contained within a range that does not impair the object of the present invention.

[0033] Examples of polyolefin resins used in the first polyolefin layer 31 include polyethylene resins, polypropylene resins, ethylene-vinyl acetate copolymers (EVA), ionomers, etc. These may be used alone or in combination of two or more. The polyolefin resin used as the main component of the first polyolefin layer 31 is a resin different from the cyclic polyolefin resin described below.

[0034] The polyolefin resin is preferably a polyethylene resin. The density of the polyethylene resin is preferably 0.880 to 0.970 g / cm 3 and more preferably 0.900 to 0.965 g / cm 3 is. Examples of polyethylene resins include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and very low-density polyethylene (VLDPE). The polyethylene resin is preferably linear low-density polyethylene (LLDPE).

[0035] As LLDPE, a copolymer of ethylene monomer as the main component and an α-olefin such as butene-1, hexene-1, octene-1, or 4-methylpentene as a comonomer, using a polymerization method using a single-site catalyst, can be preferably used. Single-site catalysts include various single-site catalysts such as metallocene catalyst systems.

[0036] Examples of the propylene-based resin include propylene homopolymer, propylene-α-olefin random copolymer, and propylene-ethylene copolymer.

[0037] (Low adsorption layer) The low-adsorption layer 32 is a layer containing a low-adsorption resin as a main component. The low-adsorption resin is a resin that does not easily adsorb active ingredients, cooling agents, and fragrances (menthol, vitamin components, etc.) contained in nutritional foods, cosmetics, and medicines, which are contents contained in the spouted pouch. The low-adsorption resin is preferably a resin that has lower adsorption properties for the contents contained in the spouted pouch than the polyolefin resin (first polyolefin layer 31) such as polyethylene resin or polypropylene resin used in the sealing layer.

[0038] As the low-adsorption resin, a cyclic polyolefin resin can be suitably used from the viewpoint of low adsorption and lamination (co-extrusion) processability with the first polyolefin layer 31 and the second polyolefin layer 33, for example.

[0039] The cyclic polyolefin resin is not particularly limited, but examples thereof include norbornene polymers, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers. Among these, norbornene polymers are preferred. Examples of norbornene polymers include ring-opening polymers (hereinafter referred to as "COP") of norbornene monomers and norbornene copolymers (hereinafter referred to as "COC") obtained by copolymerizing norbornene monomers with olefins such as ethylene. Furthermore, hydrogenated products of COP and COC are particularly preferred. The weight average molecular weight of the cyclic olefin resin is not particularly limited, but is preferably 5,000 to 500,000, and more preferably 7,000 to 300,000.

[0040] By providing a low adsorption layer 32 containing a low adsorption resin as its main component and reducing the thickness of the first polyolefin layer 31, it is possible to impart suitable low adsorption properties to the multilayer film 1 (packaging bag using the same).

[0041] The content of the low adsorption resin in the low adsorption layer 32 is preferably 70 mass% or more, more preferably 90 mass% or more, and particularly preferably 98 mass% or more, relative to the total amount of the low adsorption layer 32, and it is more preferable that the low adsorption layer 32 consists essentially of the low adsorption resin.

[0042] Commercially available cyclic polyolefin resins include, for example, "ZEONOR" manufactured by Zeon Corporation, "APEL" manufactured by Mitsui Chemicals, Inc., and "TOPAS" manufactured by Polyplastics Co., Ltd.

[0043] Examples of low-adsorption resins other than cyclic polyolefin resins include thermoplastic resins with low adsorption, such as ethylene vinyl alcohol copolymer (EVOH), polyvinyl alcohol (PVOH), polyacrylonitrile (PAN), glycol-modified polyethylene terephthalate (G-PET), amorphous polyester (A-PET), polyvinylidene chloride (PVDC), and polyxylylene adipamide (nylon MXD6).

[0044] (Second polyolefin layer) The second polyolefin layer 33 is provided on the substrate layer 2 side of the low adsorption layer 32, and contains a polyolefin resin as a main component. The polyolefin resin used as the main component of the second polyolefin layer 33 is This resin is different from the cyclic polyolefin resin.

[0045] As the polyolefin-based resin used for the second polyolefin layer 33, the same resin as the polyolefin-based resin used for the first polyolefin layer 31 can be used. It is preferable to use the same material (a material containing a polyolefin resin as a main component) for the first polyolefin layer 31 and the second polyolefin layer 33. In this case, when forming the sealant layer 3 by co-extrusion or the like, only one supply line is required for the materials used for the first polyolefin layer 31 and the second polyolefin layer 33, which can simplify the manufacturing process of the sealant layer 3 (multilayer film 1).

[0046] In the multilayer film 1 of this embodiment, the second polyolefin layer 33 is thicker than the first polyolefin layer 31 .

[0047] The ratio of the thickness of the second polyolefin layer 33 to the thickness of the first polyolefin layer 31 is preferably 1.5-40, more preferably 3-30, and even more preferably 5-30.

[0048] The thickness of the second polyolefin layer 33 is preferably 60 to 200 μm, and more preferably 100 to 160 μm.

[0049] The thickness of the first polyolefin layer 31 is preferably 5 to 40 μm, more preferably 5 to 30 μm, and even more preferably 5 to 20 μm. The thinner the first polyolefin layer 31, the better the low adsorption properties of the multilayer film 1.

[0050] The thickness of the low adsorption layer 32 is preferably 15 to 45 μm, and more preferably 15 to 30 μm. If the thickness of the low-adsorption layer 32 is too thin, components such as menthol will easily permeate, resulting in a loss of low adsorption properties.If the thickness is too thick, it will be difficult for the layer to follow the flow of the resin that constitutes the second polyolefin layer 33 during heat sealing, and it will be difficult to form a resin pool 3a that contributes to the bonding strength with the spout.

[0051] The thickness (total thickness) of the sealant layer 3 is preferably 70 to 230 μm, and more preferably 80 to 180 μm.

[0052] The thickness (total thickness) of the multilayer film 1 is preferably 90 to 300 μm, and more preferably 90 to 250 μm.

[0053] At least one of the multilayer film 1, the base layer 2, and the sealant layer 3 (first polyolefin layer 31, low adsorption layer 32, second polyolefin layer 33) may contain, as needed, components such as antifogging agents, antistatic agents, heat stabilizers, antioxidants, lubricants, antiblocking agents, release agents, UV absorbers, colorants, etc., within the scope of the present invention.

[0054] In this embodiment, the sealant layer 3 (e.g., a co-extruded film) is described as being composed of three layers: a first polyolefin layer 31, a low-adsorption layer 32, and a second polyolefin layer 33. However, the sealant layer 3 is not limited to this, and may be a sealant layer composed of four or more layers, with another resin layer laminated on the second polyolefin layer 33 (on the opposite side to the first polyolefin layer 31).

[0055] (Manufacturing method of multilayer film) The method for producing the multilayer film 1 is not particularly limited, but examples include a coextrusion method in which the resins or resin mixtures used for each layer are heated and melted in separate extruders, and then laminated in the molten state to the desired multilayer structure by a coextrusion multilayer die method, a feed block method, or the like, and then molded into a film by an inflation method, a T-die chill roll method, or the like. However, the method is not limited to this, and other methods may also be used.

[0056] The multilayer film 1 of the present invention has low adsorption properties and excellent bonding strength with the spout (bag rupture resistance), and therefore can be suitably used as a material for spout-equipped pouches for packaging liquid contents that come into contact with the inner surface of the multilayer film, including active ingredients such as food, cosmetics, and pharmaceuticals.

[0057] <Manufacturing method for spouted pouches> Using the above multilayer film 1 and spout 4, a pouch with a spout can be produced by various known methods. For example, a pouch with a spout can be produced by sandwiching the attachment portion 41 of the spout 4 between two multilayer films 1 for the side surfaces and then heat sealing the multilayer films.

[0058] (Sealing process) 6 to 12, the method for producing the spouted pouch 6 of this embodiment includes a sealing step in which a heat seal bar 51 is used to heat seal the first polyolefin layer 31 side of the multilayer film 1 while pressing it against the attachment portions 41, 42 of the spout 4 (portions to be heat sealed with the multilayer film 1).

[0059] 6 to 10 are diagrams showing the sealing process for a pouch with a boat-shaped spout. Figures 6 and 7 show the state of the spout attachment portion 41 (boat-shaped attachment portion) of a pouch with a boat-shaped spout before it is welded to the multilayer film. Figure 7(a) is a cross-sectional view of the thin end portion (thin-walled portion) of the boat-shaped attachment portion of Figure 6 taken along plane XX (an enlarged cross-sectional view of region A in Figure 6), and Figure 7(b) is a cross-sectional view of the thin end portion of Figure 6 taken along plane YY (an enlarged cross-sectional view of region B in Figure 6). As shown in Figure 6(b), the thin end portion of attachment portion 41 protruding in the vertical direction of the paper in Figure 6(b) has a tapered shape. Figures 8 to 10 show the state of the spout attachment part 41 of the pouch with a boat-shaped spout after welding to the multilayer film. Figure 9(a) is a cross-sectional view taken along plane XX in Figure 8 (an enlarged cross-sectional view of region A in Figure 8), and Figure 9(b) is a cross-sectional view taken along plane YY in Figure 8 (an enlarged cross-sectional view of region B in Figure 8).

[0060] Referring to Figures 6 to 9, when heat sealing is performed while applying pressure with heat seal bar 51, the resin that makes up spout 4 (mounting portion 41) and the resin that makes up multilayer film 1 soften or melt and are extruded toward the lower end side of mounting portion 41 of spout 4, but since the resin that makes up the outer first polyolefin layer 31 is closer to the heat seal bar and is easily heated and fluidized, part of it protrudes below mounting portion 41 of spout 4 (toward edge 41a), and a resin puddle 3a is formed at the lower end (edge ​​41a) of mounting portion 41 (see Figure 9). The resin puddle 3a also includes the low-adsorption layer 32 and the second polyolefin layer 33 that flowed together with the first polyolefin layer 31, and a part of the attachment portion 41 of the spout 4, but in the thin-walled portion 41b of the attachment portion 41 (Figures 6(b), 7(a), 8, and 9a), the part of the attachment portion 41 softens, so that the resin puddle 3a is formed in a downwardly extended state. This resin pool 3a increases the bonding area between the multilayer film 1 and the attachment portion 41 of the spout 4, and by making the bonding surface more complex, the bonding strength between the multilayer film 1 and the attachment portion 41 of the spout 4 is improved. In particular, the resin pool 3a is preferable because it is formed at the lower end (edge ​​41a) of the attachment portion 41 of the spout 4, which is prone to peeling when an impact is applied to the pouch 61.

[0061] By providing the rounded R portion 41c at the end of the mounting portion 41, the resin pool 3a can be easily attached along the surface of the R portion 41c. However, even if the R portion 41c is not provided, the resin pool 3a can be wrapped around the end of the mounting portion 41, thereby achieving the effect of improving the joining strength.

[0062] 10, when the attachment portion 41 of the spout 4 has multiple protrusions 411 extending in the width direction on the outer side (the side of the multilayer film 1), resin puddles 3b can be formed by the thick first polyolefin layer 31 so as to effectively fill the gaps between the protrusions 411. In this case, the heat seal area is smaller than when there are no protrusions 411, but the bonding strength between the multilayer film 1 and the attachment portion 41 of the spout 4 can be obtained. Here, as shown in FIG. 10, resin pools 3b may be formed on both sides of the gap between convex portions 411 in the vertical direction, or resin pools 3b may be formed on only one side of the gap between convex portions 411 in the vertical direction.

[0063] The heat sealing (thermal welding) is preferably performed by pressure bonding using a heated mold or the like as the heat seal bar 51.

[0064] However, the present invention is not limited to this, and heat sealing may be performed by ultrasonic sealing or the like. That is, heat sealing may be performed by using an ultrasonic oscillating horn as the heat seal bar 51 and pressing the ultrasonic oscillating horn against the multilayer film 1 from the side opposite the spout 4. When performing ultrasonic sealing, an anvil may be placed on the side opposite the ultrasonic oscillating horn, if necessary.

[0065] The shape of the heat seal bar 51 used for the mounting part 41 (boat-shaped mounting part) is preferably a shape having a surface (sealing surface) that follows the shape of the side surface of the mounting part 41. Using two such heat seal bars 51, the sealant layer 3 (first polyolefin layer 31) side of the multilayer film 1 is brought into contact with the mounting portion 41 of the spout 4, and the sealing surfaces of the heat seal bars 51 are pressed against both sides of the mounting portion 41, thereby heat sealing the multilayer film 1 and the mounting portion 41 of the spout 4.

[0066] It is preferable that the heat seal bar 51 has a length (i.e., a length longer than the width of the spout 4) that allows it to not only heat seal the attachment portion 41 of the spout 4 to the multilayer film 1 but also to heat seal the multilayer film 1 to each other in the direction of both ends of the attachment portion 41 (both thin portions 41b).

[0067] In a plan view of the multilayer film 1 in the thickness direction (V) during the sealing process (the state at the start of welding shown in Figure 7), it is preferable that at least a portion of the edge 51a of the heat seal bar 51 overlaps with the edge 41a of the mounting portion 41 of the spout 4 or extends beyond the edge 41a. In this case, resin pool 3a is more reliably formed at the end of mounting portion 41 of spout 4 (see FIG. 9), and therefore the bonding strength between multilayer film 1 and mounting portion 41 of spout 4 is more reliably improved. It is preferable to press the heat-softened sealed portion with a cooling seal bar (not shown) to cool and solidify it. The cooling seal bar may be one that presses over the same range as the heat seal bar 51, but it is preferable that it can press over an area that covers part or most of the resin pool 3a.

[0068] 11A and 11B are diagrams showing an example of a sealing process for an example of a pouch with a flanged spout, where (a) is a cross-sectional view showing a heat-sealing process, and (b) is a cross-sectional view showing a cool-sealing process. 11, in a plan view seen in the thickness direction (V) of the multilayer film 1 during the sealing process, the edge 51a of the heat seal bar 51 overlaps with the edge 42a of the attachment portion 42 of the spout 4 or extends outward from the edge 42a (on the side farther from the mouth body 40 in a plane perpendicular to the thickness direction of the attachment portion 42). In other words, the edge 51a of the heat seal bar 51 is positioned outward from the edge 42a of the attachment portion 42 of the spout 4. In this case, as with the pouch with the boat-shaped spout described above, a resin pool 3a is formed at the edge 42a of the attachment portion 42 of the spout 4 (see Figure 11(a)), thereby improving the bonding strength between the multilayer film 1 and the attachment portion 42 of the spout 4. It is preferable that the edge 51a of the heat seal bar 51 be positioned outside the edge 42a of the mounting portion 42 along the entire periphery, because this allows the resin pool 3a to be formed along the edge 42a of the entire periphery of the mounting portion 42. However, in cases where the flange shape of the mounting portion 42 and the shape of the heat seal bar 51 differ, part of the edge 51a of the heat seal bar 51 may be positioned outside the edge 42a of the mounting portion 42.

[0069] The attachment part 42 is provided around the mouth body 40 in a plan view seen from the thickness direction of the attachment part 42. Therefore, the shape of the attachment part 42 (the shape in a plan view seen from the thickness direction of the attachment part 42) can be said to be a shape having an opening corresponding to the mouth body 40. It is preferable that the shape of the heat seal bar 51 used for the mounting portion 42 (flange-type mounting portion) (the shape when viewed in a plan view from the thickness direction of the mounting portion 42) has an opening in the center, similar to the shape of such mounting portion 42 (flange-type mounting portion). For example, if the shape of the mounting portion 42 is a disk with a circular opening in the center (see Figure 5), it is preferable that the shape of the tip surface that becomes the sealing surface of the heat seal bar 51 is also a disk with a circular opening in the center. In this case, it is preferable that the shape of the opening of the heat seal bar 51 (the shape when viewed in a plan view from the thickness direction of the attachment portion 42) is larger than the shape of the opening of the attachment portion 42 in order to pass through the mouth body 40, which may have protrusions or the like on its outer surface.

[0070] The seal width (width of the seal bar) is, for example, 1 mm to 5 mm, and preferably 3 mm to 5 mm. Note that, for example, when the tip of the heat seal bar 51 having the sealing surface is disk-shaped with a circular opening in the center, the width of the seal bar refers to the length (width) of one radial side of the disk.

[0071] The sealing step may include a cooling step (FIG. 11(b)) in which the heat-sealed multilayer film 1 is cooled while being pressed against the attachment portion 42 of the spout 4 using a cooling seal bar 52.

[0072] 12A and 12B are diagrams showing a modified example of the sealing process for an example of a pouch with a flanged spout, where (a) is a cross-sectional view showing the heat-sealing process, and (b) is a cross-sectional view showing the cool-sealing process. 12(a), in a plan view seen from the thickness direction (V) of the multilayer film 1 during the sealing step, the edge 51a of the heat seal bar 51 is located inside the edge 42a of the attachment portion 42 of the spout 4 (the side of the attachment portion 42 closer to the mouth body 40 in the thickness direction). In other words, the edge 51a of the heat seal bar 51 is located inside the edge 42a of the attachment portion 42 of the spout 4. Note that it is preferable that the entire edge 51a of the heat seal bar 51 is located inside the edge 42a of the attachment portion 42 in order to achieve uniform sealing, but this is not necessary, and part of the edge 51a of the heat seal bar 51 may be located outside the edge 42a of the attachment portion 42. Furthermore, it is preferable that the cooling seal bar 52 can cool at least the area of ​​the heat seal bar 51 while pressing it, and it is more preferable that the cooling seal bar 52 can cool the area (the area of ​​the resin puddle 3c) that covers the outside of the edge 51a of the heat seal bar 51 while pressing it. That is, it is preferable that the edge 52a of the cooling seal bar 52 is positioned outside the position of the edge 51a of the heat seal bar 51. In this case, a puddle of resin 3c is formed above the attachment portion 42 of the spout 4 by heat sealing with the heat seal bar 51, whereby the resin puddle 3c is heated and softened to form a raised mass, and then the resin puddle 3c is cooled while being crushed by the cooling seal bar 52, and the first polyolefin layer 31 is fixed to the attachment portion 42 of the spout 4. In this way, the first polyolefin layer 31 in an increased thickness is cooled at the location of the resin puddle 3c while being pressed firmly against the attachment portion 42 of the spout 4, thereby improving the bonding strength between the multilayer film 1 and the attachment portion 42 of the spout 4. In plan view from the direction (V), the position of the edge 52a of the cooling seal bar 52 may be inside the edge 42a of the mounting portion 42 of the spout 4, overlapping it, or protruding outside it.

[0073] The present invention is not limited to the above-described embodiment, and can be modified in various ways. Two or more embodiments selected from the various embodiments described above may be combined as appropriate, or at least one configuration (part of a configuration) selected from the various embodiments described above may be replaced with part of a configuration of another embodiment.

[0074] <Summary> The following will exemplify the above-described embodiments of the present invention.

[0075] (1) A spout-equipped pouch comprising a pouch made of a multilayer film and a spout attached to the pouch, The multilayer film includes a base layer and a sealant layer provided on one surface of the base layer, The sealant layer comprises: a first polyolefin layer provided on the outermost surface opposite to the base layer and containing a polyolefin resin as a main component; a low adsorption layer provided on the base layer side of the first polyolefin layer and containing a low adsorption resin as a main component; a second polyolefin layer provided on the substrate layer side of the low adsorption layer and containing a polyolefin resin as a main component; the thickness of the second polyolefin layer is greater than the thickness of the first polyolefin layer; A spout-equipped pouch, wherein a resin pool is formed in the multilayer film on the edge side of the attachment portion of the spout.

[0076] (2) A spout-equipped pouch according to (1), wherein the resin pool is formed so as to cover a portion of the edge of the attachment portion of the spout.

[0077] (3) A multilayer film used for a spouted pouch, A substrate layer and a sealant layer provided on one surface of the substrate layer, The sealant layer comprises: a first polyolefin layer provided on the outermost surface opposite to the base layer and containing a polyolefin resin as a main component; a low adsorption layer provided on the base layer side of the first polyolefin layer and containing a low adsorption resin as a main component; a second polyolefin layer provided on the substrate layer side of the low adsorption layer and containing a polyolefin resin as a main component; A multilayer film, wherein the second polyolefin layer has a thickness greater than the thickness of the first polyolefin layer.

[0078] (4) the ratio of the thickness of the second polyolefin layer to the thickness of the first polyolefin layer is 1.5 to 40; The multilayer film according to (3), wherein the second polyolefin layer has a thickness of 60 to 200 μm, and the first polyolefin layer has a thickness of 5 to 40 μm.

[0079] (5) A sealing step is included in which the multilayer film according to (3) or (4) is heat-sealed while being pressed against the attachment portion of the spout using a heat seal bar, In a plan view seen from the thickness direction of the multilayer film in the sealing step, At least a part of the edge of the heat seal bar overlaps with or extends beyond the edge of the attachment portion of the spout. A method for manufacturing a pouch with a spout.

[0080] (6) A sealing step is included in which the multilayer film according to (3) or (4) is heat-sealed while being pressed against the attachment portion of the spout using a heat seal bar, The sealing step includes: a cooling step of cooling the heat-sealed multilayer film while pressing it against the attachment portion of the spout using a cooling seal bar; In a plan view seen from the thickness direction of the multilayer film in the sealing step, At least a part of the edge of the heat seal bar is located inside the edge of the mounting portion of the spout, The edge of the cooling seal bar is located outside the edge of the heat seal bar. A method for manufacturing a pouch with a spout. [Explanation of symbols]

[0081] 1. Multilayer film 10 Outer periphery (sealing part) 2 Base material layer 3 Sealant Layer 3a, 3b, 3c Resin pool 31 First polyolefin layer (sealing layer) 32 Low adsorption layer 33 Second polyolefin layer 4 spout 40 Mouth body 41 Mounting part (boat-shaped part) 41a edge 41b Thin wall part 41c R section 411 Convex 42 Mounting part (flange part) 42a edge 43 Cap 51 Heat seal bar 52 Cooling seal bar 6 spout pouches 61 pouches 61a Heaven Gazette Department 61b Torso 61c bottom gusset

Claims

1. A spout-equipped pouch comprising a pouch made of a multilayer film and a spout attached to the pouch, The multilayer film includes a base layer and a sealant layer provided on one surface of the base layer, The sealant layer comprises: a first polyolefin layer provided on the outermost surface opposite to the base layer and containing a polyolefin resin as a main component; a low-adsorption layer provided on the base layer side of the first polyolefin layer and containing a low-adsorption resin as a main component; a second polyolefin layer provided on the substrate layer side of the low adsorption layer and containing a polyolefin resin as a main component, the thickness of the second polyolefin layer is greater than the thickness of the first polyolefin layer; A spout-equipped pouch, wherein a resin pool is formed in the multilayer film on the edge side of the attachment portion of the spout.

2. The spout-equipped pouch according to claim 1 , wherein the resin pool is formed so as to cover a part of an edge of the attachment portion of the spout.

3. A multilayer film used for a spouted pouch, A substrate layer and a sealant layer provided on one surface of the substrate layer, The sealant layer comprises: a first polyolefin layer provided on the outermost surface opposite to the base layer and containing a polyolefin resin as a main component; a low-adsorption layer provided on the base layer side of the first polyolefin layer and containing a low-adsorption resin as a main component; a second polyolefin layer provided on the substrate layer side of the low adsorption layer and containing a polyolefin resin as a main component, A multilayer film, wherein the second polyolefin layer has a thickness greater than the thickness of the first polyolefin layer.

4. a ratio of the thickness of the second polyolefin layer to the thickness of the first polyolefin layer is 1.5 to 40; The multilayer film according to claim 3, wherein the second polyolefin layer has a thickness of 60 to 200 μm, and the first polyolefin layer has a thickness of 5 to 40 μm.

5. a sealing step of heat-sealing the multilayer film according to claim 3 while pressing it against the attachment portion of the spout using a heat seal bar; In a plan view seen from the thickness direction of the multilayer film in the sealing step, At least a part of the edge of the heat seal bar overlaps with or extends beyond the edge of the attachment portion of the spout. A method for manufacturing a pouch with a spout.

6. a sealing step of heat-sealing the multilayer film according to claim 3 while pressing it against the attachment portion of the spout using a heat seal bar; The sealing step includes: a cooling step of cooling the heat-sealed multilayer film while pressing it against the attachment portion of the spout using a cooling seal bar; In a plan view seen from the thickness direction of the multilayer film in the sealing step, At least a part of the edge of the heat seal bar is located inside the edge of the mounting portion of the spout, The edge of the cooling seal bar is located outside the edge of the heat seal bar. A method for manufacturing a pouch with a spout.

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