Ink storage component for writing instruments

Abstract

To provide a liquid storage member for an applicator which allows an influence on environment to be further reduced by changing a material of an intermediate layer disposed between an inner layer and an outer layer whose base materials are made of paper from conventional aluminum to silica in a paper-made refill for a writing instrument.SOLUTION: An ink storage member for a writing instrument has at least three layers including an inner layer made of a paper base material, an intermediate layer formed on an external surface of the inner layer, and an outer layer made of a paper base material and formed on an external surface of the intermediate layer. The intermediate layer has at least one of an aluminum oxide film layer, a silica film layer formed of low-molecular silane, and a silica film layer formed of polysilazane.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to an ink reservoir for a writing instrument made of paper material. [Background technology]

[0002] Traditionally, transparent or translucent plastics such as polypropylene have been used for the ink reservoirs of writing instruments such as ballpoint pens. However, in recent years, with growing momentum to address global environmental issues, including reducing the use of plastics, proposals focusing on plastic-free alternatives have been made for each component of writing instruments.

[0003] For example, Patent Document 1 discloses an ink storage member for a writing instrument that uses a multilayered ink storage tube formed by molding one or more layers of other resins inside a storage tube base molded from a biodegradable resin. According to this document, the storage tube base molded from a biodegradable resin biodegrades over time, thus contributing to reducing the amount of waste to be disposed of.

[0004] On the other hand, a writing instrument has also been proposed that uses paper as a base material, laminated with a synthetic resin or metal such as aluminum that has barrier properties, and has a barrel made by spiral molding this composite material (Patent Document 2). To improve water resistance and gas barrier properties, this barrel has a structure in which, from the outer surface of the barrel, two layers of aluminum foil label paper with a kraft paper backing and liner paper are layered, followed by a polyethylene layer on the inner surface, and then a polyester film with an aluminum vapor-deposited film on the outside. According to Patent Document 2, by using a composite material including a paper base material for the barrel, it is possible to provide a writing instrument that can achieve low pollution while maintaining durability.

[0005] Furthermore, Patent Document 3 discloses a liquid-containing member for an applicator having at least three layers: an inner layer of a paper substrate, an intermediate layer formed on the outer circumferential surface of the inner layer and being a metal layer or a silica vapor-deposited layer, and an outer layer formed on the outer circumferential surface of the intermediate layer and being made of a paper substrate. In this liquid-containing member, the paper substrate laminate and the outer layer are wound in a spiral shape in contact with each other so that their adjacent surfaces do not overlap, and ink leakage is prevented by leaving a gap of 1 mm or more and half the width of the outer layer between the joints of the outer layers and between the paper substrate laminates.

[0006] Patent Document 4 discloses an ink reservoir for a writing instrument, in which an ink reservoir tube is constructed using paper as a base material, and one end of the ink reservoir tube is connected to a connection portion formed on a writing member or an intermediate member that supports the writing member. In this ink reservoir, a locking means capable of ensuring a certain connection strength to the ink reservoir tube is provided at the connection portion of the intermediate member that supports the writing member, thereby providing a practical writing instrument. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2001-146091 [Patent Document 2] Japanese Patent Application Laid-open No. 62-70097 [Patent Document 3] Japanese Patent Publication No. 2021-16976 [Patent Document 4] Japanese Patent Publication No. 2020-172044 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, since all ink-containing materials use paper as a base material, composite materials are used in which synthetic resins or metals such as aluminum are laminated to the paper base material to impart strength, gas barrier properties, etc. For example, there are many types of aluminum alloys, and it is not easy to extract high-purity aluminum, which presents problems in terms of recyclability, and there is room for further consideration in order to reduce the environmental impact. The present invention aims to provide a liquid container for an applicator that further reduces environmental impact by replacing the material of the intermediate layer between the inner and outer layers, both of which are based on paper, from conventional aluminum to a specific silica film in a writing instrument paper refill. [Means for solving the problem]

[0009] The ink-containing member for a writing instrument of the present invention has at least three layers, comprising an inner layer of a paper substrate, an intermediate layer formed on the outer surface of the inner layer, and an outer layer of a paper substrate formed on the outer surface of the intermediate layer, wherein the intermediate layer has at least one of the following: an aluminum oxide film layer, a silica film layer formed of low molecular weight silane, and a silica film layer formed of polysilazane. The intermediate layer preferably has an aluminum oxide film layer, a silica film layer formed from low molecular weight silane, or a silica film layer formed from polysilazane on one or both sides of the paper substrate.

[0010] It is preferable that the inner layer and the intermediate layer, or the intermediate layer and the outer layer, are bonded together with an olefin-based adhesive or a silane coupling agent. Preferably, at least one of the paper substrates forming the inner and outer layers is glassine paper. [Effects of the Invention]

[0011] In this invention, by making at least one of the following intermediate layers between the inner and outer layers, both made of paper substrates: an aluminum oxide film layer, a silica film layer obtained by reacting with a low-molecular-weight silane, and a silica film layer obtained by reacting with a polysilazane, the ink-retaining member can be given higher water repellency and durability compared to conventional writing instruments that use aluminum in the intermediate layer. The silica film layer is a silica coating obtained by reacting a low-molecular-weight silane or polysilazane on the surface of the paper substrate. The intermediate layer may have a layer of aluminum oxide film or silica film on one or both sides of the paper substrate. The silica film adheres strongly to the paper substrate layer. By using a cyclic olefin polymer as an adhesive between the inner layer, intermediate layer, or outer layer, high gas barrier properties can be imparted to the ink-containing material. According to the present invention, it is possible to provide an ink storage member for writing instruments that further reduces the environmental impact. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 shows a configuration in which an ink reservoir for a writing instrument has adhesive layers between the inner layer and the intermediate layer, and between the inner layer and the outer layer. [Figure 2] Figure 2 shows an example of the configuration of a refill including the ink-containing member for a writing instrument according to the present invention. Figure 2(a) is a front view of the external appearance of the refill, and Figure 2(b) is a cross-sectional view of the refill taken along the line A-A'. [Figure 3]FIG. 3 is a diagram showing a three-layer or five-layer structure of an inner layer, an intermediate layer, and an outer layer that constitute an ink storage member for a writing instrument according to the present invention. FIG. 3(a) shows a form having an adhesive layer between a paper base material layer, a silica film layer (or an aluminum oxide film layer), and the paper base material layer in a three-layer structure, and FIG. 3(b) is a schematic cross-sectional view of the forms of Examples 1 to 4. In a five-layer structure having an inner layer made of a paper base material, an intermediate layer having silica film layers (or aluminum oxide film layers) on both surfaces of the paper base material layer, and an outer layer made of a paper base material, a form having adhesive layers between the inner layer and the intermediate layer and between the intermediate layer and the outer layer is shown.

Mode for Carrying Out the Invention

[0013] The ink storage member for a writing instrument of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a diagram showing an example of the configuration of a refill including an ink storage member 10 for a writing instrument according to the present invention. FIG. 2(a) shows a front view of the appearance of the refill, and FIG. 2(b) shows a cross-sectional view of the refill taken along the line A-A'.

[0014] In FIG. 2, for example, a refill housed in the shaft cylinder of a ballpoint pen is an ink storage member 10 for a writing instrument (hereinafter also simply referred to as "ink storage member 10") which is a long and thin cylindrical ink storage tube made of paper as a base material and storing ink not shown, a joint 11 attached to the tip of the ink storage member 10, and a ballpoint pen tip 12 attached to the tip of the joint 11 as a writing member.

[0015] Specifically, the joint 11 has a cylindrical rear end portion that joins with the ink storage member 10 and a cylindrical front end portion with an outer diameter larger than that of the rear end portion. A ballpoint pen tip 12 is attached to this front end portion. Further, an adhesive is pre-applied to the rear end portion of the joint 11 at the joint portion with the ink storage member 10 to provide a certain bonding strength. In this state, the rear end portion of the joint 11 is press-fitted into the inner part of the front end of the ink storage member 10, thereby joining the joint 11 and the ink storage member 10. As a result, the ink storage member 10 and the ballpoint pen tip 12 are connected via the joint 11 so that ink can flow through them.

[0016] The ink storage member 10 for the writing instrument of the present invention has at least three layers including an inner layer 1 of a paper base material, an intermediate layer 2 formed on the outer surface of the inner layer 1, and an outer layer 3 of a paper base material formed on the outer surface of the intermediate layer 2. Therefore, the ink storage member 10 for the writing instrument may be, for example, a four-layer structure in which an outer layer 3 is further stacked on the three-layer structure, or a six-layer structure in which the three-layer structure composed of the inner layer 1, the intermediate layer 2, and the outer layer 3 is stacked twice. FIG. 1 shows a form in which an adhesive layer 5 is provided between the inner layer 1 and the intermediate layer 2 and / or between the intermediate layer 2 and the outer layer 3 in the ink storage member 10 having a three-layer structure.

[0017] As the paper base materials constituting the inner layer 1 and the outer layer 3, various known materials such as high-quality paper, medium-quality paper, single-sided glossy paper, kraft paper, single-sided kraft paper, bleached kraft paper, cardboard, white cardboard, liner, lightly coated paper, coated paper, art paper, cast coated paper, glassine paper, and parchment paper can be used. These paper base materials may be used alone or in combination of two or more kinds.

[0018] Among these paper substrates, glassine paper, which is high-density, highly transparent, and has oil and water resistance, is preferred. Glassine paper is made by highly beating virgin pulp to form paper, then processing it under high pressure in a supercalender to compress and smooth the pulp fibers and make it dense. Its thickness is usually 20 to 50 μm. When used as the inner layer 1, the thickness of the glassine paper is preferably 20 to 60 μm, and when used as the outer layer, it is preferably 20 to 200 μm. The density of the glassine paper is 0.8 g / cm³. 3 It is preferable to keep the above in place. Furthermore, a silicone oil or the like may be applied to the inside of the inner layer 1 that comes into contact with the ink to provide water repellency.

[0019] Intermediate layer 2 is a layer having an aluminum oxide film layer or a silica film layer. The silica film layer uses polysilazane or low molecular weight silane as a precursor. Figure 3(a) schematically shows a configuration in which intermediate layer 2 between inner layer 1 and outer layer 3 is a silica film. The intermediate layer 2 may have a layer of aluminum oxide film or silica film on one or both sides of the paper substrate. Figure 3(b) is a schematic cross-sectional view of the embodiments of Examples 1 to 4, which schematically shows an embodiment in which the intermediate layer 2 between the inner layer 1 and the outer layer 3 is a layer having an aluminum oxide film layer or silica film layer including the paper substrate. The paper substrate used consists of paper substrates that make up the inner layer 1 and the outer layer 3. Polysilazanes include perhydropolysilazanes, which form inorganic coatings, and organic polysilazanes, which form inorganic-organic hybrid coatings with higher coating performance. Perhydropolysilazanes are inorganic polymers soluble in organic solvents, composed solely of Si-H, NH, and Si-N bonds. Perhydropolysilazanes react with moisture in the air to introduce silyl groups, generating ammonia, and condensing to form a highly hard amorphous silica film. Commercially available perhydropolysilazanes include, for example, Durazane 2800 (Merck) and Durazane 2200 (Merck), which are known as coating solutions dissolved in organic solvents.

[0020] Organic polysilazanes (also called organopolysilazanes) include, for example, methylpolysilazane and dimethylpolysilazane. Commercially available organic polysilazanes include, for example, Durazane 1033 (Merck) and Durazane 1500 RC (Merck). Perhydropolysilazanes and organic polysilazanes are dissolved in aromatic or cyclic aliphatic solvents, ethers, or volatile organic solvents such as halogenated hydrocarbons. A solution of these solutions is applied to the surfaces of the inner layer 1 and outer layer 3 using a dip coating method or a spin coating method, and then heat-treated at 150-180°C to form a silica film. Because the silica film formed using the polysilazane is brittle due to its high hardness, its thickness is usually preferably 300 to 1300 μm, and particularly preferably 500 to 900 μm.

[0021] Low molecular weight silanes have multiple organic functional groups and hydrolyzable alkoxy groups within their molecules, and form amorphous silica coatings by dehydration crosslinking. Because low molecular weight silanes are low molecular weight, they penetrate more easily into the fine irregularities on the surfaces of the inner layer 1 and outer layer 3 compared to polysilazanes, and adhere closely to the inner layer 1 and outer layer 3 with a strong anchoring effect. The thickness of the silica layer formed using low molecular weight silane is preferably 300 to 1000 μm, and particularly preferably 500 to 900 μm. Even when using polysilazanes and low-molecular-weight silanes, the resulting silica coating exhibits higher gas barrier properties compared to silica vapor-deposited films.

[0022] A layer made of adhesive (hereinafter referred to as "adhesive layer 5") may be present between the inner layer 1 and the intermediate layer 2, and between the intermediate layer 2 and the outer layer 3. For the adhesive, an olefin-based adhesive or a silane coupling agent is preferred. The olefin-based adhesive or silane coupling agent acts as an adhesive that bonds the inner layer 1, the intermediate layer 2, and the outer layer 3 together, and also serves to reinforce the paper substrate.

[0023] Olefin adhesives are adhesives made from polyolefin resins such as polyethylene ionomers, polyethylene elastomers, high-density polyethylene, low-density polyethylene, polypropylene ionomers, polypropylene elastomers, and cyclic olefin polymers. Polyolefin resins also include modified polyolefin resins such as maleic anhydride-modified polypropylene. Among these polyolefin resins, cyclic olefin polymers are preferred because they can impart gas barrier properties. Cyclic olefin polymers include, for example, cycloolefin polymers such as polymers obtained by ring-opening polymerization and hydrogenation of norbornene compounds, and cycloolefin copolymers such as copolymers of tetracyclododecene and olefins such as ethylene.

[0024] As the olefin-based adhesive, one or more types selected from the polyolefin resins may be used in combination. The olefin-based adhesive may be applied directly to the inner layer 1 and the outer layer 3, or it may be used in the form of a dispersion-type or emulsion-type resin liquid with a polyolefin resin as the base polymer. A silane coupling agent, as described later, may be added to the resin liquid as needed.

[0025] A silane coupling agent is a compound having both a site that reacts with organic compounds and a site that reacts with inorganic compounds. The silane coupling agent chemically bonds the interface between the paper substrate of the inner layer 1 or outer layer 3 and the silica coating of the intermediate layer 2, preventing water intrusion and improving the durability and weather resistance of the ink-containing member 10. Suitable silane coupling agents include epoxy, vinyl, styryl, methacrylic, acrylic, amino, isocyanurate, ureido, mercapto, isocyanate, and acid anhydride types. Specifically, these include vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl Examples of suitable chemicals include hydrochloride of 2-aminoethyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, tris(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, and 3-trimethoxysilylpropyl succinic anhydride.

[0026] For example, when bonding inner layer 1 and intermediate layer 2 using an olefin-based adhesive or silane coupling agent, the adhesive is applied in a raised manner near the center of either inner layer 1 or intermediate layer 2. Then, while pressing inner layer 1 and intermediate layer 2 together, the adhesive is spread over the entire bonding surface, ensuring that no air bubbles remain in the bonding area and that there are no bonding defects. After bonding inner layer 1 and intermediate layer 2 together, pressure is applied to fix them in place until the adhesive hardens. For the inner layer 1 or intermediate layer 2, the adhesive should be 5-50 g / m². 2 Degree, preferably 5-25 g / m 2 Apply in this amount.

[0027] The ratio of the thicknesses (μm) of the inner layer 1, intermediate layer 2, and outer layer 3 is typically 20-60:300-1000:20-200, and preferably 20-30:500-900:50-200. The ratio of the thickness of the paper substrate of inner layer 1 or outer layer 3 to the thickness of the layer formed by the aluminum oxide or silica coating of intermediate layer 2 is approximately 1 / 2 to 1 / 1200. For example, the combined thickness of inner layer 1 and outer layer 3 is 40 to 260 μm, and the thickness of intermediate layer 2 is 300 to 1300 μm.

[0028] The laminated paper, in which an inner layer 1, an intermediate layer 2, and an outer layer 3 are laminated in this order, is cut into strip-shaped sheets with a width of 4 to 20 mm using a bobbin slitter or the like. Next, these strip-shaped sheets are formed into a cylindrical shape by rolling them using a spiral machine or the like. Forming into a cylindrical shape means using one or more sheets of the laminated paper cut to the predetermined width, for example, 2 to 4 sheets, and winding them around a core rod to form a tube. The strip-shaped sheets are wound around a mandrel (paper tube manufacturing machine) with the inner layer 1 on the inside. There are several winding methods, such as winding the sheet around the core rod in a spiral (spiral winding) and winding the sheet perpendicular to the core rod (flat winding), but spiral winding is preferable from the viewpoint of strength. It is preferable to treat the surface of the mandrel with an appropriate lubricant beforehand to facilitate the removal of the mandrel, or to apply an appropriate amount of lubricant to the side of the inner layer 1 that is wound around the mandrel. When layering two or more sheets of laminated paper, apply adhesive to the outer layer 3, and then wrap it spirally so that the inner layer 1 of the laminated paper is on the inside.

[0029] To spirally wind the laminated paper onto the mandrel, it is preferable to use a strip-shaped sheet with a width of 5 to 15 mm. By spiral winding with such wide laminated paper, the required length of the liquid-containing member 10 can be reached without winding many times, and as a result, the number of contact surfaces between the laminated papers is reduced, which helps to suppress leakage of the ink contained in the ink-containing member 10.

[0030] As described above, in a preferred embodiment of the ink storage member 10 of the present invention, the laminated paper is wound spirally along the longitudinal direction of the ink storage member 10 so that adjacent surfaces do not overlap. Even if adjacent surfaces overlap at the contact points between the laminated paper, i.e., at the seams 4, 4', the overlap width is limited to a maximum of 1 mm. By ensuring that the seams 4, 4' do not overlap, or by limiting the overlap width to a maximum of 1 mm, ink leakage from the seams 4, 4' can be suppressed. If the overlap width at the seams 4, 4' exceeds 1 mm, a step will be created in the overlapping portion, which may cause ink leakage.

[0031] Even when wrapping another sheet of laminated paper on top of a spirally wound laminated paper, it is preferable to wrap the other laminated paper so that its adjacent surfaces are in contact with each other. However, when wrapping two or more layers of laminated paper, there is no problem of liquid leakage even if the seams of the outermost layer of laminated paper of the ink-containing member 10 overlap slightly.

[0032] The ink storage member 10 is completed by cutting a cylindrical molded body, from which a mandrel has been drawn, to the required predetermined length and drying it for several hours under appropriate temperature and humidity.

[0033] The dimensions of the ink reservoir 10 are those used in ordinary writing instruments and are not particularly limited, but are generally 1.5 to 5 mm in inner diameter, 1.8 to 10 mm in outer diameter, and 30 to 150 mm in length.

[0034] The tensile strength of the ink-containing member 10 is preferably 3.5 kN / m or more, more preferably 4.5 kN / m or more, and even more preferably 5.5 kN / m or more, from the viewpoint of obtaining excellent strength for the paper packaging as a whole. The tensile strength is measured by the tensile strength test method specified in JIS P 8113:2006.

[0035] The writing instruments of the present invention include, for example, fountain pens, ballpoint pens, marking pens, felt-tip pens, correction tools, and brush pens. In this case, the ink contained in the ink storage member 10 may be either water-based (gel) ink or oil-based ink, and depending on the type of pen, ink for ballpoint pens or marking pens may be used as appropriate. [Examples]

[0036] The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples. The ink storage member of the present invention was evaluated by the following method. (1) Bending test With a support distance of 64 mm, the center of paper tube 1 was pressed down at a speed of 100 mm / min using a bending wedge jig, and the measured value at the time of buckling was defined as the bending strength. A bending strength of 4.0 N or more was marked with ○, a bending strength exceeding 2.0 N but less than 4.0 N was marked with △, and a bending strength of 2.0 N or less was marked with ×.

[0037] (2) Tensile strength The tensile strength was measured using a horizontal tensile testing machine (manufactured by Kumagai Riki Kogyo Co., Ltd.) in accordance with the tensile strength test method specified in JIS P 8113:2006. A tensile strength of 3.5 kN / m or more was marked with ○, a value greater than 1.5 kN / m but less than 3.5 kN / m was marked with △, and a value of 1.5 kN / m or less was marked with ×.

[0038] [Example 1] A silica film was formed by coating the entire front and back surfaces of high-quality paper (Shiraoi; manufactured by Nippon Paper Industries Co., Ltd.) with a solution of 15g of tetraethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 15g of organic polysilazane (Durazane 1500RC; manufactured by Merck Co., Ltd.) dissolved in dibutyl ether, and then heat-treating the solution at 180°C. Next, an olefin-based adhesive (Chemipearl S500; manufactured by Mitsui Chemicals, Inc.) is applied to the silica film formed on both sides of the high-quality paper, and two sheets of glassine paper (25 μm thick, basis weight 25 g / m²) are formed. 2 , density 1.0g / cm 3 A laminated paper having a layered structure consisting of glassine paper, silica film, high-quality paper, silica film, and glassine paper was prepared by bonding them together in a sandwich-like manner. The thickness of the laminated paper was 791 μm, the total thickness of the silica film was 571 μm, and the total thickness of the adhesive layer was 8.5 μm. The laminating paper was cut to a width of 13 mm using a bobbin slitter. A spiral-shaped cylindrical body was created by winding strips of laminated paper around the outer surface of a mandrel in a paper tube manufacturing machine (Langston). During this process, the laminated paper strips were wound so that adjacent surfaces did not overlap, but rather butted together. The obtained spiral tube was cut to a length of 89.3 mm to obtain an ink-containing member with an inner diameter of 3.8 mm. The results are shown in Table 1. Both bending strength and tensile strength were within the range of ○.

[0039] [Example 2] Laminated paper was prepared in the same manner as in Example 1, except that 3-glycidoxypropyltrimethoxysilane (KBM-1083; manufactured by Shin-Etsu Silicone Co., Ltd.) was used as a silane coupling agent instead of the olefin-based adhesive. A spiral-shaped cylindrical body was fabricated in the same manner as in Example 1, and then cut to obtain an ink-containing member. The results are shown in Table 1. Both bending strength and tensile strength were within the range of ○.

[0040] [Example 3] In Example 1, a laminated paper was prepared in the same manner as in Example 1, except that an olefin-based adhesive (Chemipearl S500, manufactured by Mitsui Chemicals, Inc.) was used in combination with a silane coupling agent, specifically 3-methacryloxypropylmethyldimethoxysilane (KBM-502, manufactured by Shin-Etsu Silicone Co., Ltd.). A spiral-shaped cylindrical body was fabricated in the same manner as in Example 1, and then cut to obtain an ink-containing member. The results are shown in Table 1. Both bending strength and tensile strength were within the range of ○.

[0041] [Example 4] A silica film was formed by coating one side of a sheet of high-quality paper (Shiraoi; manufactured by Nippon Paper Industries Co., Ltd.) with a solution of 15g of tetraethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 15g of organic polysilazane (Durazane 1500RC; manufactured by Merck Co., Ltd.) dissolved in dibutyl ether, and then heat-treating the solution at 180°C. Next, an aluminum oxide film was formed on one side of the other high-quality paper by sputtering. A resin solution containing an olefin-based adhesive (Chemipearl S500, manufactured by Mitsui Chemicals, Inc.) and 3-methacryloxypropylmethyldimethoxysilane (KBM-502, manufactured by Shin-Etsu Silicone Co., Ltd.) is applied to the surface of a silica coating and an aluminum oxide film on high-quality paper, and two sheets of glassine paper with a thickness of 25 μm (basis weight 25 g / m²) are then used. 2, density 1.0 g / cm 3 ) were adhered so as to sandwich them, and a laminated paper having a laminated structure composed of glassine paper, silica film, high-quality paper, aluminum oxide film and glassine paper was produced. The thickness of the laminated paper was 785 μm, the thickness of the silica film was 456 μm, the thickness of the aluminum oxide film was 114 μm, and the total thickness of the adhesive layer was 8.5 μm. In the same manner as in Example 1, a spiral cylindrical body was produced and cut to obtain an ink storage member. The results are shown in Table 1. Both the bending strength and the tensile strength were ○.

[0042] [Comparative Example 1] A silica vapor deposition film with a thickness of 10 μm was formed on the entire surface and back surface of high-quality paper (Shiraoi; manufactured by Nippon Paper Industries Co., Ltd.). Next, an olefin-based adhesive (Chemipar S500 manufactured by Mitsui Chemicals, Inc.) was applied onto the silica vapor deposition layers formed on both sides of the high-quality paper, and two sheets of glassine paper with a thickness of 25 μm (basis weight 25 g / m 2 , density 1.0 g / cm 3 ) were adhered so as to sandwich them, and a laminated paper having a laminated structure composed of glassine paper, silica vapor deposition layer, high-quality paper, silica vapor deposition layer and glassine paper was produced. The total thickness of the laminated paper was 757 μm, the total thickness of the silica vapor deposition film was 610 μm, and the total thickness of the adhesive layer was 6.1 μm. The laminated paper was cut to a width of 13 mm with a bobbin slitter. In the same manner as in Example 1, a spiral cylindrical body was produced and cut to obtain an ink storage member. In the ink storage member of Comparative Example 1, since the intermediate layer 2 was a silica vapor deposition film, sufficient strength could not be obtained as compared with the ink storage members 10 of Examples 1 to 3.

[0043] [Reference Example] In Comparative Example 1, a laminated paper having a layered structure consisting of glassine paper, aluminum foil, high-quality paper, aluminum foil, and glassine paper was prepared in the same manner as in Comparative Example 1, except that a 6.5 μm thick aluminum foil was laminated to the entire front and back surfaces of high-quality paper (Shiraoi; manufactured by Nippon Paper Industries Co., Ltd.) instead of a silica vapor-deposited layer. The total thickness of the laminated paper was 732 μm, the total thickness of the aluminum foil was 602 μm, and the total thickness of the adhesive layer was 6.5 μm. The laminating paper was cut to a width of 13 mm using a bobbin slitter. A spiral-shaped cylindrical body was fabricated in the same manner as in Example 1, and then cut to obtain an ink-containing member. The reference example ink storage member, in which the intermediate layer 2 is made of aluminum foil, is equivalent in performance to the ink storage members 10 of Examples 1 to 4. However, aluminum has problems in terms of environmental impact and recyclability, so the consideration of alternative materials is a challenge.

[0044] Table 1 shows the materials and evaluation results of the ink-containing members in Examples 1-4, Comparative Example 1, and Reference Example. [Table 1]

[0045] In this embodiment, as an example, the intermediate layer 2 is configured as a single layer with a silica film layer or an aluminum oxide film layer formed on both sides of the paper substrate, but it is not limited to this. The number of layers in the intermediate layer 2 may be two or three or more, depending on the usage conditions of the writing instrument and the product specifications (material, dimensions, etc.). In this case, at least one of the layers of the intermediate layer 2 other than the outermost layer (the innermost layer and the intermediate layer) may be a paper substrate layer. Furthermore, the adhesive layer that adheres each layer of the intermediate layer 2 only needs to be able to prevent ink from leaking outside the ink storage member 10, and depending on the usage conditions of the writing instrument and the product specifications, one or more of the layers of the intermediate layer 2 other than the outermost layer (the innermost layer and the intermediate layer) may suffice. [Explanation of symbols]

[0046] 10. Ink storage component for writing instruments 11 Fittings 12 ballpoint pen tips 1, 1' Inner layer 2, 2' Mesopotamian layer 3 outer layer 4, 4' joint 5 Adhesive layer

Claims

1. It has at least three layers, consisting of an inner layer of paper substrate, an intermediate layer formed on the outer surface of the inner layer, and an outer layer of paper substrate formed on the outer surface of the intermediate layer. An ink-containing member for a writing instrument, characterized in that the intermediate layer has at least one of the following: an aluminum oxide film layer, a silica film layer formed of a low molecular weight silane with a thickness of 300 to 1000 μm, and a silica film layer formed of a polysilazane with a thickness of 300 to 1300 μm, which is the silica film layer formed of the low molecular weight silane or the silica film layer formed of the polysilazane.

2. The ink-containing member for a writing instrument according to claim 1, wherein the intermediate layer has, on one or both sides of the paper substrate, at least one of the following: the aluminum oxide film layer, the silica film layer formed of a low molecular weight silane having a thickness of 300 to 1000 μm, and the silica film layer formed of a polysilazane having a thickness of 300 to 1300 μm, which is the silica film layer formed of the low molecular weight silane or the silica film layer formed of the polysilazane.

3. The ink-containing member for a writing instrument according to claim 1 or 2, wherein the inner layer and the intermediate layer, or the intermediate layer and the outer layer, are bonded together with an olefin-based adhesive or a silane coupling agent.

4. The ink-containing member for a writing instrument according to claim 1 or 2, wherein at least one of the paper substrates forming the inner layer and the outer layer is glassine paper.

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