Odor-proof bag

Abstract

To provide odor-proof bags that offer excellent odor-blocking properties and can be manufactured inexpensively even in small batches. [Solution] The odor-proof bag 1 is formed such that the surface coat layer of the three-layer laminated sheet 10, which consists of an olefin resin sheet layer, an aluminum vapor-deposited layer, and a surface coat layer 16 laminated in this order, is the outer surface, and preferably the olefin resin sheet layer is made of polypropylene film. The odor-proof bag has an opening 11 and a closing means for keeping the opening closed after the contents are inserted.

Description

Technical Field

[0001] This invention relates to a deodorant bag.

Background Art

[0002] In the case of temporary storage in a house, a nursing facility, a hospital, etc., or when going out, bags for storing odorous wastes such as used diapers and dirt are desired to have a function of suppressing the leakage of odors to the surrounding environment from the viewpoint of preventing the diffusion of bad odors. Also, in the case of bags for storing foods with strong odors, it may be desirable to have a similar function from the viewpoint of preventing the transfer of scents and the diffusion of odors to the surroundings during temporary storage or when going out.

[0003] As bags that can have such a function, conventionally, packaging bags using multi-layer films in which various layers are laminated have been proposed (see Patent Documents 1 and 2). Patent Document 1 discloses a deodorant bag using a resin film in which an inner layer containing LLDPE, calcium hydroxide particles, and a surfactant of 1000 ppm or less, a first adhesive layer, an odor barrier layer, a second adhesive layer, and an outer layer containing LLDPE are laminated in this order. Patent Document 2 discloses a packaging bag for odor absorption using a laminated film in which a base material layer of polyethylene terephthalate, a dry lamination adhesive layer, a barrier layer of aluminum foil, a dry lamination adhesive layer, a reinforcing layer of nylon film, an odor absorption layer containing nanozeolite, and a sealant layer of LLDPE are laminated in this order.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Odor-proof bags formed using multilayer films as described in Patent Documents 1 and 2 are indeed capable of preventing odors and fragrances from leaking out of their contents. This odor-proof effect is usually attributed to the fact that these multilayer films have a multilayer structure of five or more layers, as mentioned above. However, manufacturing such multilayer films with five or more layers requires large-scale equipment, and production costs become high when attempting small-lot production. Therefore, there is room for improvement in providing various odor-proof bags that meet user needs while ensuring good odor protection and at a low cost.

[0006] Therefore, the objective of this invention is to provide an odor-proof bag that has good odor-proof properties and can be manufactured inexpensively even in small batches. [Means for solving the problem]

[0007] The inventors of this invention conducted thorough research to solve the aforementioned problems. As a result, they discovered that by using a three-layer laminated sheet in which aluminum vapor deposition is applied to one surface of an olefin resin sheet, and a surface coating layer is formed by coating the surface of the resulting aluminum vapor deposition layer, and by forming a bag with the surface coating layer as the outer surface, the bag has good odor-proof properties. Furthermore, they discovered that because this odor-proof bag has a three-layer structure, it does not require large-scale equipment, can be used for small-lot production, and can provide various odor-proof bags that meet the needs of users at a low cost. The gist of this invention relates to the following (1) to (5).

[0008] (1) A deodorizing bag formed in which an olefin resin sheet layer, an aluminum vapor-deposited layer, and a surface coating layer are laminated in this order, with the surface coating layer being the outer surface. (2) The odor-proof bag according to item (1) above, wherein the olefin resin sheet layer is made of a polypropylene film. (3) The odor-proof bag according to item (2) above, wherein the polypropylene film is an unstretched polypropylene film. (4) The odor-proof bag according to any one of paragraphs (1) to (3) above, wherein the surface coating layer is a dried and solidified product of varnish containing at least one resin selected from acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polyurethane resin, chlorinated polyolefin resin, chlorinated rubber resin, ethylene-vinyl acetate copolymer resin, and polyamide resin. (5) The odor-proof bag according to any of paragraphs (1) to (4) above, wherein the odor-proof bag has an opening and a closing means for keeping the opening closed after the contents have been inserted. [Effects of the Invention]

[0009] According to this invention, it is possible to provide an odor-proof bag that has good odor-proof properties and can be manufactured inexpensively even in small batches. [Brief explanation of the drawing]

[0010] [Figure 1] An explanatory diagram of an odor-proof bag according to an embodiment of the present invention. [Figure 2] A schematic explanatory diagram showing section II of Figure 1. [Figure 3] A schematic diagram showing the II-II section of Figure 1. [Figure 4] An explanatory diagram of an odor-proof bag according to another embodiment of the present invention. [Modes for carrying out the invention]

[0011] The odor-proof bag according to the embodiment of the present invention is formed by laminating a three-layer sheet in which an olefin resin sheet layer, an aluminum vapor-deposited layer, and a surface coating layer are laminated in that order, with the surface coating layer being the outer surface. The odor-proof bag according to the embodiment will be described below with reference to the drawings.

[0012] Figure 1 is a schematic explanatory diagram showing an odor-proof bag 1 according to a typical embodiment of the present invention. The odor-proof bag 1 is formed using a three-layer laminated sheet 10. The shape of the odor-proof bag 1 is a rectangle formed by overlapping three rectangular three-layer laminated sheets 10, with an opening 11 that is closed on three sides and open on one side. By placing the contents into the hollow part (inside) 17 of the odor-proof bag 1 through the opening 11 and closing the opening 11 in a predetermined manner, the contents can be sealed inside the odor-proof bag 1, effectively suppressing the leakage of odor or fragrance from the contents. In this embodiment, the opposite side of one side of the opening 11 is formed by a bottom portion 12 where the three-layer laminated sheets 10 are continuous, formed by folding the three-layer laminated sheets 10. The other pair of opposite sides of the rectangle is formed by a pair of side portions 13, 13 formed by joining the overlapping three-layer laminated sheets 10 together. Furthermore, the three-layer laminated sheet 10 is constructed such that the surface coating layer 16, described later, forms the outer surface and the olefin resin sheet layer 14 forms the inner surface.

[0013] As shown in Figures 2 and 3, the three-layer laminated sheet 10 has a three-layer structure in which an olefin resin sheet layer 14, an aluminum vapor-deposited layer 15, and a surface coating layer 16 are laminated in this order.

[0014] The olefin resin sheet layer 14 is formed from an olefin resin film. The olefin resin that can be used to form the film is not particularly limited, as long as it allows for aluminum deposition. Examples include polyethylene, polypropylene, polybutene-1, polymethylpentene, and norbornene resins. Of these, polyethylene and polypropylene are preferred, and polypropylene is more preferred, from the viewpoints of heat resistance, moisture resistance, heat sealability, and cost.

[0015] Polyethylene may be polyethylene alone, or it may be a copolymer of ethylene and a monomer copolymerizable with ethylene. Examples include low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), ultra-low-density polyethylene (ULDPE), ethylene-α-olefin copolymer (EOR / EAO), and ethylene-octene,hexene copolymer.

[0016] Polypropylene may be polypropylene alone, or it may be a copolymer of propylene and a monomer copolymerizable with propylene. Polypropylene (PP) can be classified into isotactic polypropylene (IPP), syndiotactic polypropylene (SPP), and atactic polypropylene (APP) based on the stereoregularity of the arrangement of methyl groups, but there are no particular limitations. Furthermore, when polypropylene is a copolymer, for example, a random copolymer containing 1% to 7% by weight of ethylene and butene-1, or a block copolymer containing 20% ​​by weight or less of ethylene-propylene copolymer (EPR) blocks can be applied.

[0017] Olefin resins may contain additives such as fillers, as needed.

[0018] The method for forming an olefin resin film is not particularly limited, and conventional forming methods can be adopted. Generally, from the perspective of productivity, extrusion molding is preferred. The outline of extrusion molding is as follows. A molten sheet with a desired thickness and width is formed from the olefin resin melted by an extruder using a T-die, and the molten sheet is cooled and solidified by the cooling roll of a casting device, and then wound by a winder to obtain an olefin resin film. Further, after cooling and solidifying the molten sheet with a casting device, it may be stretched in the length direction (vertical direction) of the sheet, and then stretched in the width direction (horizontal direction) orthogonal to the length direction and heat-treated to perform a biaxial stretching treatment for heat setting to obtain an olefin resin film. Note that a film obtained by a method that does not perform the former biaxial stretching treatment is called an unstretched olefin resin film, and a film obtained by a method that performs the latter biaxial stretching treatment is called a biaxially stretched olefin resin film.

[0019] The method for forming an olefin resin film can be appropriately selected according to the characteristics of the resin used. When the olefin resin is polypropylene, an unstretched polypropylene film is preferred from the perspective of the tear resistance of the deodorant bag.

[0020] The thickness of the olefin resin sheet layer 14 can be appropriately determined according to the application and the like. 15 to 60 μm is preferred, 20 to 60 μm is more preferred, and 20 μm is particularly preferred.

[0021] The aluminum vapor deposition layer 15 is formed on one surface of the olefin resin sheet layer 14. By having the aluminum vapor deposition layer 15, it is possible to prevent the leakage of odors and scents derived from the contents from the outer surface of the deodorant bag. Further, when the contents of the deodorant bag 1 are affected by light, the deterioration of the contents can be suppressed by the light shielding property of the aluminum vapor deposition layer 15. From these perspectives, the aluminum vapor deposition layer 15 is preferably formed on the entire one surface of the olefin resin sheet layer. Note that, if necessary, in order to enable confirmation of the contents of the deodorant bag, a portion where the aluminum vapor deposition layer 15 is not provided may be provided as a content confirmation window.

[0022] The method for forming the aluminum vapor-deposited layer 15 is not particularly limited. Examples include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) methods such as plasma chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition. Furthermore, when providing the aluminum vapor-deposited layer 15 on one surface of the olefin resin sheet layer 14, one surface of the olefin resin sheet layer 14 may be subjected to physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment, or glow discharge treatment, or chemical treatments such as oxidation treatment using chemicals, as necessary.

[0023] The thickness of the aluminum layer can be set appropriately, taking into consideration factors such as odor-blocking effect and cost.

[0024] The surface coating layer 16 is formed to cover the surface of the aluminum vapor-deposited layer 15. This prevents the aluminum vapor-deposited layer 15 from peeling off and improves the deodorizing performance.

[0025] The surface coating layer 16 contains a resin component. The resin component is not particularly limited, and various resins used in overprint varnishes can be used, for example. Specifically, at least one resin selected from acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polyurethane resin, chlorinated polyolefin resin, chlorinated rubber resin, ethylene-vinyl acetate copolymer resin, and polyamide resin is preferred.

[0026] The surface coating layer 16 can be formed as a coating film mainly composed of resin components by applying a varnish containing at least one resin selected from, for example, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polyurethane resin, chlorinated polyolefin resin, chlorinated rubber resin, ethylene-vinyl acetate copolymer resin, and polyamide resin to the surface of the aluminum vapor-deposited layer 15, drying and solidifying it. The varnish is a solution obtained by dissolving these resins in a solvent. Examples of solvents that can be used include toluene, xylene, ethyl acetate, butyl acetate, isopropyl alcohol, and butanol. Stabilizers, antioxidants, antistatic agents, etc., may be added to the varnish as needed.

[0027] The thickness of the surface coating layer 16 can be adjusted considering the effect of preventing peeling of the aluminum vapor deposition layer 15. Typically, it is 0.5 to 10 μm, and preferably 1 to 5 μm.

[0028] The surface coating layer 16 is preferably a coating film obtained by applying a varnish containing a resin component to the surface of the aluminum vapor-deposited layer 15, drying and solidifying it, as described above; in other words, it is a dried and solidified product of the aforementioned resin-containing varnish. This eliminates the need to provide an adhesive layer between the aluminum vapor-deposited layer 15 and the surface coating layer, and allows for a simple protective layer to be provided for the aluminum vapor-deposited layer 15. The concentration of the resin component in the varnish used to form the surface coating layer 15 and the application conditions can be appropriately determined considering the final thickness of the surface coating layer 16. Furthermore, the drying and solidification conditions can be determined according to standard methods.

[0029] As shown in Figures 1-3, the odor-proof bag 1 has a structure in which a single rectangular 3-layer laminated sheet 10 is folded and stacked so that the surface coating layer 16 is on the outer surface to form a rectangle, and the other pair of opposite sides of the folded 3-layer laminated sheet 10 are joined together to form the sides 13, 13 so that the opposite side of the folded portion that forms the bottom 12 opens up to form the opening 11. There are no particular limitations on the method of joining the stacked 3-layer laminated sheets 10, but heat sealing is preferred from the viewpoint of joining strength and productivity. In this embodiment, an example in which one pair of opposite sides of the rectangle is joined is shown, but two 3-layer laminated sheets 10 may be used and three sides may be joined together to make a rectangular sheet-shaped odor-proof bag 1 with an opening 11. It is also possible to join one opening of a cylindrical 3-layer laminated sheet 10 to make a bag shape. However, in this case, a complex process is required to form the aluminum vapor-deposited layer 15 over the entire outer surface of the cylindrical three-layer laminated sheet 10, resulting in lower productivity compared to the case where the three-layer laminated sheet 10 is folded and formed into a bag shape as described above.

[0030] The shape of the odor-proof bag 1, as shown in the embodiment in Figure 1, is a rectangular sheet formed by overlapping films when empty, but it is not limited to this. It may also be a triangle, a polygon with pentagons or more, or a circular, elliptical, heart-shaped, star-shaped, etc., as appropriate. From the viewpoint of productivity, a rectangular shape is particularly preferred. Furthermore, it may be in a form other than a sheet formed by overlapping films when empty, for example, a cylindrical shape or a polyhedron with 4 or more faces. From the viewpoint of productivity, a sheet shape is particularly preferred.

[0031] The size of the odor-proof bag 1 can be determined appropriately depending on the intended use. In the case of the odor-proof bag 1 according to the embodiment shown in Figure 1, for example, the dimensions can be 100-800 mm x 70-650 mm (length x width).

[0032] In the odor-proof bag according to the embodiment of the present invention, the opening provided in the odor-proof bag may have a closing mechanism to maintain the opening closed after the contents have been inserted. Figure 4 schematically shows a typical odor-proof bag 2 according to another embodiment having such a closing mechanism.

[0033] The odor-proof bag 2 according to the embodiment shown in Figure 4 is a modified version of the odor-proof bag 1 shown in Figure 1, in which a flap portion 18 is provided by extending only one sheet 10 of the stacked three-layer laminated sheet 10 from the opening 11 to the side opposite the hollow portion 17. Furthermore, an adhesive portion 19 is provided on the surface of the olefin resin sheet layer 14 of the flap portion 18, which adheres closely to the surface coating layer 16 that forms the outer surface of the odor-proof bag 2 and can fix the flap portion 18 to the surface coating layer 16. In this modified version, the flap portion 18 and the adhesive portion 19 constitute the closing means. In addition, a protective sheet may be provided on the surface of the adhesive portion 19 to cover the outer surface of the adhesive portion 19 as needed. The protective sheet can be removed when closing the opening 11. The adhesive portion 19 is not particularly limited as long as it can be bonded to the olefin resin sheet layer (polyolefin resin film) and detachably attached to the protective sheet, and a known adhesive resin composition can be used. Furthermore, if an adhesive portion 19 is provided, the surface of the olefin resin sheet layer (polyolefin resin film) may be subjected to physical or chemical treatment as described above, if necessary.

[0034] Furthermore, in the odor-proof bag 2 according to the embodiment shown in Figure 4, a flap portion 18 and an adhesive portion 19 are provided. However, the flap portion 18 may be omitted, and the adhesive portion may be provided at a desired position on the surface coating layer 16 which forms the outer surface of the odor-proof bag 1 shown in Figure 1. In addition to such a flap portion 18 and adhesive portion 19, or a closing means using only an adhesive portion, other examples of closing means include, but are not limited to, a string that is bundled around the opening 11 and then fixed in a predetermined position so as to be able to be wound around to maintain the opening 11 in a closed state, or a linear zipper with opposing male and female parts along the opening periphery of the opening 11 that can be fitted together.

[0035] As described above, the odor-proof bags 1 and 2 according to the embodiment of this invention are formed from a predetermined three-layer laminated sheet 10, which suppresses the leakage of odors and fragrances from the contents from the surface of the sheet 10, and can be manufactured efficiently even in small batches. Therefore, it is possible to provide various odor-proof bags that meet the needs of users at a low cost. [Examples]

[0036] The embodiments of the present invention will be described in more detail below based on the examples.

[0037] (Example 1) A sheet was prepared by applying a varnish containing polyamide resin and an organic solvent to the outer surface of the aluminum vapor-deposited layer of an unoriented polypropylene film, on which one surface had an aluminum vapor-deposited layer formed. After drying the varnish and removing the organic solvent, a surface coat layer formed of a dried and solidified product containing polyamide resin was created to produce a three-layer laminated sheet. The three-layer laminated sheet had a three-layer structure consisting of an unoriented polypropylene sheet layer (thickness 20-60 μm), an aluminum vapor-deposited layer, and a surface coat layer (thickness 1-4 μm).

[0038] Using the obtained three-layer laminated sheet, an odor-proof bag 1 with the structure shown in Figures 1-3 was fabricated. Specifically, the three-layer laminated sheet 10 was folded and overlapped, and heat-sealed so that the three-layer laminated sheet 10 was continuous at the bottom 12, and the sheets 10 were heat-sealed together at the sides 13, 13 to form an opening 11 on opposite sides of the bottom 12, thereby fabricating the odor-proof bag 1. The size of the odor-proof bag 1 was 230 mm x 330 mm, with an opening formed on one of the shorter sides.

[0039] (Comparative Example 1) A deodor-proof bag was prepared in the same manner as in Example 1, except that a commercially available low-density polyethylene (LDPE) film (thickness 20-30 μm) was used and an aluminum vapor deposition layer and a surface coating layer were not formed.

[0040] (evaluation) <Gas barrier properties test> Ammonia gas and trimethylamine gas were sealed into the odor-proof bags prepared in Example 1 and Comparative Example 1 at concentrations of approximately 100 ppm and 70 ppm, respectively. Next, the odor-proof bags containing each gas were placed in sample bags, and pure nitrogen gas was sealed inside. After standing at room temperature for 0 and 24 hours, the gas concentrations in the sample bags were quantitatively analyzed using the detector tube method. The results are shown in Table 1. The results in Table 1 are the average values ​​for n=3.

[0041] [Table 1]

[0042] As shown in Table 1, the odor-proof bag of Example 1 effectively prevents the leakage of ammonia and trimethylamine compared to the odor-proof bag of Comparative Example 1. Thus, by using a predetermined laminated sheet, it is possible to effectively prevent odor leakage even with a three-layer structure. Furthermore, because it is a three-layer structure, it can be easily manufactured, and odor-proof bags can be provided inexpensively even in small-lot production. [Explanation of Symbols]

[0043] 1, 2 Odor-proof bags 10 3-layer laminated sheet 11 Opening 12 Bottom 13 Side 14. Olefin-based resin sheet layer 15. Aluminum vapor-deposited layer 16. Surface coating layer 17 Hollow part (inside) 18 Flap section 19 Adhesive part

Claims

1. A deodor-proof bag formed by laminating a three-layer laminated sheet in which an olefin resin sheet layer, an aluminum vapor-deposited layer, and a surface coating layer are laminated in that order, with the surface coating layer being the outer surface.

2. The odor-proof bag according to claim 1, wherein the olefin resin sheet layer is formed of a polypropylene film.

3. The odor-proof bag according to claim 2, wherein the polypropylene film is an unstretched polypropylene film.

4. The odor-proof bag according to claim 1 or 2, wherein the surface coating layer is a dried and solidified varnish containing at least one resin selected from acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polyurethane resin, chlorinated polyolefin resin, chlorinated rubber resin, ethylene-vinyl acetate copolymer resin, and polyamide resin.

5. The odor-proof bag according to claim 1 or 2, wherein the odor-proof bag has an opening and a closing means for maintaining the opening closed after contents are inserted.

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