Ink bag

Abstract

To provide an ink bag which reduces environmental loads, and can improve sustainability.SOLUTION: An ink bag is composed of a laminate 10 in which a plurality of films are laminated, wherein the plurality of films consist solely of a polyethylene-based resin film or a polypropylene-based resin film, in the plurality of films, an innermost layer 11 contacting a content is a sealant layer, and the sealant layer consists of a polyethylene-based resin film or a polypropylene-based resin film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ink bag. [Background technology]

[0002] Inkjet printers are provided with replaceable ink cartridges that store ink to be supplied to the recording head. A known ink cartridge structure is one in which an ink bag containing ink is housed inside a hard case (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-49513 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional ink bags, a composite material made of nylon, polyester, etc. is used on the outside of the heat seal layer. When recycling ink cartridges, there is a problem that it is difficult to recycle ink bags made of composite materials.

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an ink bag that can reduce the environmental load and improve sustainability. [Means for solving the problem]

[0006] A first aspect of the present invention is an ink bag consisting of a laminate of multiple films, wherein the multiple films are made only of polyethylene-based resin film or polypropylene-based resin film, and the innermost layer of the multiple films that comes into contact with the contents is a sealant layer, and the sealant layer is made of polyethylene-based resin film or polypropylene-based resin film.

[0007] In a second embodiment, in the first embodiment, the polyethylene resin film or polypropylene resin film used for the sealant layer is a film to which no slip agent, antistatic agent, or antiblocking agent is added. A third aspect is the first or second aspect, wherein the outermost film of the plurality of films is made of a stretched polypropylene resin film.

[0008] In a fourth aspect, in any one of the first to third aspects, among the plurality of films, a film other than the sealant layer includes a vapor-deposited film. A fifth aspect is the fourth aspect, wherein the vapor-deposited film is a metal vapor-deposited film or a transparent vapor-deposited film. A sixth aspect is the fourth or fifth aspect, wherein two or more of the vapor-deposited films are laminated between the outermost film of the plurality of films and the sealant layer. In a seventh aspect, in any one of the fourth to sixth aspects, the vapor-deposited film has a vapor-deposited layer only on the surface of the resin film opposite to the sealant layer, other than the sealant layer. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an ink bag that can reduce the environmental load and improve sustainability. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a cross-sectional view showing a first example of a laminate used in an ink bag. [Figure 2] FIG. 10 is a cross-sectional view showing a second example of a laminate used in an ink bag. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described below based on preferred embodiments.

[0012] The ink bag of this embodiment is made of a laminate formed by stacking multiple films. A first example of a laminate 10 shown in Fig. 1 has multiple films, including an innermost layer 11, an outermost layer 12, and an intermediate layer 13. A second example of a laminate 20 shown in Fig. 2 has multiple films, including an innermost layer 21, an outermost layer 22, and intermediate layers 23 and 24. Although not specifically shown, the laminate may have only two layers of films, the innermost layer and the outermost layer.

[0013] The multiple films are made of only polyethylene-based resin films or polypropylene-based resin films, which allows for the construction of a mono-material ink bag, thereby reducing the environmental impact and improving sustainability.

[0014] In the laminate constituting the ink bag of this embodiment, of the multiple films, the innermost layers 11, 21 that come into contact with the contents are sealant layers, and the sealant layers are made of a polyethylene-based resin film or a polypropylene-based resin film. This allows the melting point during sealing when producing the ink bag to be lower than that of polypropylene-based resin, improving productivity. The ink that will be the content of the ink bag is in a liquid or fluid state before use in printing.

[0015] Polyethylene resin films are single-layer or multi-layer resin films made of polyethylene resins. Examples of polyethylene resins include polyethylene (PE), such as linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE). Polyethylene resins may be ethylene homopolymers or ethylene-based copolymers. The resin material of polyethylene resin films may be one type of polyethylene resin or a blend of two or more types of polyethylene resins.

[0016] A polypropylene-based resin film is a single-layer or multi-layer resin film made of a polypropylene-based resin. Examples of polypropylene-based resins include propylene homopolymers (homo PP) and propylene-ethylene copolymers. Examples of propylene-ethylene copolymers include random copolymers (random PP) and block copolymers (block PP). The resin material of the polypropylene-based resin film may be one type of polypropylene-based resin or a blend of two or more types of polypropylene-based resins.

[0017] Examples of comonomers in polyethylene-based resins include α-olefins such as propylene, 1-butene, 1-hexene, and 1-octene, and other vinyl-based monomers. Examples of comonomers in polypropylene-based resins include α-olefins such as ethylene, 1-butene, 1-hexene, and 1-octene, and other vinyl-based monomers. Examples of other vinyl-based monomers include cyclic olefins such as norbornene, vinyl acetate, vinyl chloride, and acrylic acid. In polyethylene-based resins and polypropylene-based resins, one type of comonomer may be used, or two or more types may be used.

[0018] The proportion of ethylene in the constituent monomers of the polyethylene resin is preferably 50% by weight or more, and may be, for example, 80 to 100% by weight. The ethylene or comonomer used in the polyethylene resin may be a compound derived from a fossil resource such as petroleum, or may be a compound derived from biomass such as plants. The resin contained in the polyethylene resin layer may be only a polyethylene resin.

[0019] The proportion of propylene in the constituent monomers of the polypropylene-based resin is preferably 50% by weight or more, and may be, for example, 80 to 100% by weight. The propylene or comonomer used in the polypropylene-based resin may be a compound derived from a fossil resource such as petroleum, or may be a compound derived from biomass such as plants. The resin contained in the polypropylene-based resin layer may be only a polypropylene-based resin.

[0020] The polyethylene-based resin film and the polypropylene-based resin film may contain additives other than the resin. The additives are not particularly limited, but examples thereof include antioxidants, slip agents, antiblocking agents, flame retardants, UV absorbers, light stabilizers, antistatic agents, colorants, crosslinking agents, etc. The additives may be either components that are compatible with the resin or components that are not compatible with the resin.

[0021] The sealant layer that may come into contact with the ink of the contents is preferably an additive-free polyethylene resin film or an additive-free polypropylene resin film. Here, "additive-free" means that at least a slip agent, an antistatic agent, and an antiblocking agent are not added. Furthermore, other additives may also be not added. Examples of slip agents include fatty acid amides such as erucic acid amide. Examples of antistatic agents include surfactants and electrolytes (inorganic salts, organic salts). Examples of antiblocking agents include inorganic particles such as metal oxides and organic particles such as resin particles.

[0022] By using an additive-free polyethylene-based resin film or an additive-free polypropylene-based resin film as the sealant layer of the ink bag, it is possible to prevent additives from leaching out into the ink contained therein. Unintentional impurities that are inevitably contained during the production of polyethylene-based or polypropylene-based resins may be contained in the sealant layer. Examples of unavoidable impurities include residues of catalysts used in the polymerization of polyethylene-based or polypropylene-based resins.

[0023] The sealant layer may be a single-layer resin film or a multi-layer sealant film. The sealant layer may contain one or more sealant materials. Examples of sealant materials include LDPE, LLDPE, MDPE, and PP. At least a portion of the sealant material may be an amorphous resin, an acid-modified resin, or the like.

[0024] A multilayer sealant film can be formed by laminating two or more resin layers by coextrusion or the like. The multilayer sealant film may have two or more polyethylene-based resin layers, or may have two or more polypropylene-based resin layers. Furthermore, the multilayer sealant film may include a resin layer made of ethylene-vinyl alcohol copolymer (EVOH). Examples of layer configurations of sealant films containing EVOH include PE / EVOH / PE (innermost layer), EVOH / PE (innermost layer), PP / EVOH / PP (innermost layer), and EVOH / PP (innermost layer).

[0025] EVOH can be obtained by saponifying a copolymer containing ethylene and a vinyl ester monomer to convert at least a portion of the vinyl ester units into vinyl alcohol units. Examples of the vinyl ester monomer include vinyl carboxylates such as vinyl formate, vinyl acetate, vinyl butyrate, and vinyl benzoate. The ethylene content of EVOH is, for example, 20 to 60 mol%. The degree of saponification of EVOH is not limited to 100 mol%, but is preferably, for example, 80 mol% or higher.

[0026] In the laminate constituting the ink bag, it is preferable that the films other than the sealant layer among the multiple films include a vapor-deposited film. Examples of the films other than the sealant layer include intermediate layers 13, 23, and 24 or outermost layers 12 and 22. Examples of vapor-deposited films include a configuration in which a vapor-deposited layer such as a metal vapor-deposited layer or an inorganic vapor-deposited layer is laminated on at least one side of a resin layer. Vapor-deposited materials used for the vapor-deposited layer include aluminum, silica, and alumina. When a metal such as aluminum is vapor-deposited, an opaque metal vapor-deposited film can be obtained. When a metal oxide such as silica or alumina is used, a transparent vapor-deposited film can be obtained.

[0027] Two or more vapor-deposited films may be laminated between the outermost film and the sealant layer among the multiple films. For example, in the laminate 20 shown in Fig. 2, the intermediate layers 23 and 24 may be vapor-deposited films.

[0028] The vapor-deposited film may have a vapor-deposited layer only on the surface of the resin film other than the sealant layer opposite the sealant layer. For example, in the laminate 20 shown in Fig. 2, the vapor-deposited films of the intermediate layers 23 and 24 may have a vapor-deposited layer only on the surface facing the outermost layer 22. In this case, the vapor-deposited layers laminated on the intermediate layers 23 and 24 are not laminated only via an adhesive layer, which makes it possible to suppress foaming of the adhesive layer.

[0029] In the laminate constituting the ink bag, at least the outermost film among the multiple films is preferably made of a stretched polypropylene resin film. The stretched polypropylene resin film may be any resin film made of stretched polypropylene (OPP), and may be uniaxially or biaxially stretched, with or without a vapor deposition layer. If the laminate has an intermediate layer, it is preferable that the intermediate layer also be made of a stretched polypropylene resin film.

[0030] Although not shown, an adhesive layer, a resin layer, or the like may be interposed between the layers of the multiple films. The adhesive layer can be formed from an adhesive, an anchor coating agent, an extruded resin layer, or the like. Examples of adhesives include urethane-based adhesives and polyester-based adhesives, and further include solvent-based and solventless adhesives. Examples of extruded resin layers include resin layers formed by extruding a polyethylene-based resin or a polypropylene-based resin between the layers.

[0031] The method for producing the laminate that constitutes the ink bag is not particularly limited, but examples include dry lamination, extrusion lamination, and multilayer co-extrusion, or a combination of two or more of these. The resin film other than the sealant layer may have a printed layer for displaying or designing the contents of the ink bag.

[0032] The ink bag may have any of a three-sided sealed bag, a four-sided sealed bag, a pillow bag, a gusset bag, a standing pouch, etc. The position and shape of the sealed portion can be set appropriately depending on the type of packaging bag. For example, in the case of a four-sided sealed bag, the sealed portions are arranged on the four sides of the periphery of the ink storage portion. In the case of a three-sided sealed bag, the sealed portions are arranged on three sides of the periphery of the ink storage portion, and the remaining side is formed by the fold line formed by folding the laminate in half.

[0033] The method for manufacturing an ink bag from a laminate having a sealant layer as the innermost layer is not particularly limited, but it can be produced by overlapping the laminate so that the sealant layer is on the side that contacts the ink and heat sealing it. The ink bag of this embodiment may constitute an ink cartridge by itself, or may be constructed by placing the ink bag inside a hard case. The ink bag may be a packaging bag without a pouring outlet, or may be a packaging bag with a spout-type pouring outlet.

[0034] The type of ink filled in the ink bag is not particularly limited, but examples include water-based ink, alcohol-based ink, oil-based ink, etc. The colorant of the ink may be a pigment or a dye. The use of the ink is also not particularly limited, but examples include various printing uses such as inkjet printing, letterpress printing, gravure printing (intaglio printing), and offset printing (planographic printing). [Example]

[0035] The present invention will be specifically described below with reference to examples.

[0036] A laminate was produced with the composition shown in Table 1. In the composition column, the diagonal line " / " inserted between each layer indicates that the layers are laminated with an adhesive layer or the like. The left side of the composition indicates the outermost layer, the right side indicates the innermost layer, and the space between them indicates the intermediate layer. The symbols representing the resins that make up each layer have the following meanings:

[0037] PET: Polyethylene terephthalate Ny: Nylon PE: Polyethylene (sealant layer) OPP: Oriented polypropylene CPP: Non-oriented polypropylene (sealant layer) MDOPE: Polyethylene uniaxially oriented in the machine direction (MD) BOPE: Biaxially oriented polyethylene EVOH: Ethylene-vinyl alcohol copolymer EVOH co-extruded PE: Multilayer sealant made by co-extruding EVOH with PE

[0038] In the symbols for each layer, VM stands for metal vapor deposition, and tVM stands for transparent vapor deposition (metal oxide). These symbols are connected to the symbol for resin with a horizontal line (-). When they are to the left of the symbol for resin, they represent vapor deposition on the side farther from the sealant layer, and when they are to the right of the symbol for resin, they represent vapor deposition on the side closer to the sealant layer.

[0039] [Table 1]

[0040] The recyclability shown in Table 1 was rated as "Good" when the multiple films constituting the laminate consisted only of polyethylene-based resin films or polypropylene-based resin films, and "Poor" when other films were included.

[0041] In the drop tests shown in Table 1, Test A was conducted in which 40cc of content was filled into a gusseted ink bag measuring 40mm x 100mm x 15mm. Test B was conducted in which 1.6L of content was filled into a gusseted ink bag measuring 180mm x 385mm x 45mm. In both Tests A and B, the filled ink bag was placed horizontally and dropped once from a height of 1.2m at room temperature. If the bag was not broken, it was marked as "Good", and if it was broken, it was marked as "Poor".

[0042] The additive amounts shown in Table 1 are for erucamide, an additive that may be included in the sealant layer. If the amount is less than 2 ppm by weight, it is marked as "<2." In the innermost layer column, it is marked as "No additive." If the amount of additive is greater than that, the corresponding value is also listed. The normal amount of additive is 250 ppm by weight.

[0043] The barrier properties shown in Table 1 were measured by the Mocon method (isobaric method) of JIS K7129-2 (Plastics - Films and sheets - Determination of water vapor transmission rate - Part 2: Infrared sensor method) under the conditions of a permeation cell temperature of 40°C, a low humidity chamber of 0% RH, and a high humidity chamber of 100% RH. The water vapor transmission rate (WVTR) was measured in units of g / (m 2 ·24h).

[0044] The appearance shown in Table 1 was rated as "x" when bubbles were visible to the naked eye, and "o" when bubbles were not visible to the naked eye.

[0045] The processing suitability shown in Table 1 was evaluated as "Good" when the difference between the melting point of the resin in the outermost layer of the laminate and the melting point of the resin in the innermost layer was 30°C or more, and as "Poor" when it was 29°C or less (less than 30°C).

[0046] The laminate of Example 1 uses PET and Ny for the film, which makes it difficult to recycle and places a heavy burden on the environment. The laminates of Examples 2 to 14 had good recyclability, reduced environmental impact, and improved sustainability, and furthermore, did not break in drop test A. The laminate of Example 11 had a small difference in melting point between the outermost layer and the innermost layer, and therefore had poor processability, and broke in drop test B. The laminate of Example 12 broke in drop test B because CPP, which has inferior impact resistance compared to PE, was used in the sealant layer. The laminate of Example 14 had poor processability due to the small difference in melting point between the outermost layer and the innermost layer, but did not break in Drop Test B due to the use of biaxially oriented PE. [Explanation of symbols]

[0047] 10, 20... laminate, 11, 21... innermost layer, 12, 22... outermost layer, 13, 23, 24... intermediate layer.

Claims

1. An ink bag made of a laminate of multiple films, the plurality of films are composed solely of polyethylene-based resin films or polypropylene-based resin films, The ink bag is characterized in that, among the plurality of films, the innermost layer that comes into contact with the contents is a sealant layer, and the sealant layer is made of a polyethylene-based resin film or a polypropylene-based resin film.

2. 2. The ink bag according to claim 1, wherein the polyethylene resin film or polypropylene resin film used for the sealant layer is a film containing no slip agent, antistatic agent, or antiblocking agent.

3. 2. The ink bag according to claim 1, wherein the outermost film of the plurality of films is made of a stretched polypropylene resin film.

4. 2. The ink bag according to claim 1, wherein the films other than the sealant layer among the plurality of films include a vapor-deposited film.

5. 5. The ink bag according to claim 4, wherein the vapor-deposited film is a metal vapor-deposited film or a transparent vapor-deposited film.

6. 5. The ink bag according to claim 4, wherein two or more vapor-deposited films are laminated between the outermost film of the plurality of films and the sealant layer.

7. 7. The ink bag according to claim 6, wherein the vapor-deposited film has a vapor-deposited layer only on the surface of the resin film other than the sealant layer, opposite to the sealant layer.

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