JP2003320783A - Ink housing tube for writing instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink housing tube for a writing instrument which has sufficient permeability resistance and moisture absorption resistance to permeability of a solvent and absorption of a moisture even in various type environments and has excellent aging storability of an ink. <P>SOLUTION: The ink housing tube for the writing instrument houses the ink containing the solvent selected from the group consisting of an alcohol or the like having 4C or more Cs in a molecule, a polyhydric alcohol or the like and a glycol monoether or the like. The containing tube has a laminated structure extrusion molded by two or more types of thermoplastic resins. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink container for a writing instrument, which is suitable for use as an ink container for a writing instrument such as an ink container for an oil-based ballpoint pen and has excellent storage stability of ink over time.

[0002]

2. Description of the Related Art Conventionally, linear inks such as polypropylene and polyethylene are usually used for ink storage tubes for writing instruments, and oil-based ballpoint pens also use ink containers made of polypropylene as ink storage tubes. is doing.

This is because the solvent of the conventional oil-based ink for ballpoint pens uses a solvent with a low vapor pressure of 0.01 mmHg or less and has a low hygroscopicity. This is because there was no point in changing the polypropylene ink containing tube, which is not so problematic and has a cost advantage.

On the other hand, a laminate having a conventional laminated structure uses an amide resin for gas barrier for preventing external oxygen, carbon dioxide and water and polyethylene or polypropylene for preventing water from the resin. . Usually, these amide resins for gas barriers and resins such as polyethylene and polypropylene do not have affinity for each other, so it is common to provide an adhesive layer to bond the two resins together. At present, there is no other method than using a metal tube.

On the other hand, the present applicant has found that the number of carbon atoms in the molecule is 4
We have developed inks for writing instruments that have excellent writing performance and dryness of writing lines, and strikethrough of handwriting, using the above alcohols, polyhydric alcohols, and solvents selected from glycol monoethers as the main solvent of the ink. .

However, when the ink containing the solvent is filled in the ink container made of polypropylene, the permeability of the solvent and the hygroscopicity of water become insufficient,
A problem arises in that the ink is poor in storability over time.
Further, as described above, an adhesive for laminating a layer of an amide resin completely different in properties from the olefin resin used to prevent external influences such as a laminate represented by a mayonnaise container. In the one provided with a layer, in the above solvent, the amide resin layer swells with water because the solvent content that has been held in the linear olefin resin greatly affects moisture absorption under high humidity, There is a problem in that the amide resin layer is deteriorated as the solvent permeates. Furthermore, if there is an adhesive layer or the like for adhering different resin layers, since there is an affinity between both layers, water and solvent components accumulate and swell, and lose transparency. There is a problem in the point.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems and the present situation, and is intended to solve the problems. Alcohols having 4 or more carbon atoms in the molecule, polyhydric alcohols, glycol mono In an ink container for a writing instrument, which contains an ink containing a solvent selected from ether, it can be sufficiently satisfied with respect to the permeability of the solvent and the hygroscopicity of water even under a wide variety of environments, and the ink can be stored for a long time. It is an object of the present invention to provide an ink storage tube for a writing instrument that is excellent in storability.

[0008]

Means for Solving the Problems As a result of extensive studies on the above-mentioned problems of the prior art, the present inventor has found that a solvent selected from alcohols having 4 or more carbon atoms in the molecule, polyhydric alcohols and glycol monoethers. It was found that the ink containing tube for a writing instrument having the above-mentioned purpose can be obtained by making the structure of the ink containing tube for a writing instrument containing the ink containing the above into a specific structure, thereby completing the present invention. The present invention resides in the following (1) to (4). (1) An ink containing tube for a writing instrument, which contains an ink containing a solvent having 4 or more carbon atoms in the molecule, a solvent selected from polyhydric alcohols and glycol monoethers, wherein the ink containing tube for the writing instrument is An ink container for a writing instrument, which is formed by extrusion molding of two or more thermoplastic resins and has a laminated structure without an adhesive layer. (2) The ink container for a writing instrument as described in (1) above, wherein the thermoplastic resin is an olefin resin. (3) The ink container for a writing instrument as described in (1) or (2) above, wherein the thermoplastic resin is an olefin resin having visibility. (4) At the rear end of the writing instrument ink storage tube, any one of the above (1) to (3), characterized in that it has an ink follower that prevents solvent evaporation and moisture absorption of the writing instrument ink. Ink storage tube for the writing instrument described.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The ink container for a writing instrument of the present invention is an ink container for a writing instrument which contains an ink containing a solvent having a carbon number in the molecule of 4 or more, a polyhydric alcohol, and a glycol monoether. It is characterized in that the ink containing tube for a writing instrument has a laminated structure excluding an adhesive layer extruded from two or more kinds of thermoplastic resins.

The ink container for a writing instrument according to the present invention comprises:
It is necessary to have a laminated structure having no adhesive layer extruded from two or more thermoplastic resins, that is, two or more thermoplastic resins having different properties. The thermoplastic resin used for the ink container for a writing instrument having a laminated structure formed by this extrusion molding is not particularly limited as long as it exhibits the effects of the present invention, and examples thereof include polypropylene (PP) and polyethylene (PE). ), Cyclic polyolefin, polymethylpentene, polyethylene terephthalate (PET), polybutylene terephthalate (PB)
T), polystyrene (PS), polycarbonate (P
C), acrylonitrile-butadiene-styrene copolymer (ABS), nylon resin (polyamide), polyethylene imide (PEI), polyphenylene sulfide (PPS), polysulfone (PSU), aliphatic polyketone, polyether sulfone (PES), Thermoplastic resins such as polyarylate (PAR), polyphenylene ether (PPE), silicone elastomers, olefin elastomers, polyvinyl chloride, polyvinylidene chloride, preferably solvent resistance, moldability, environmental resistance, transparency,
An olefin thermoplastic resin selected from polypropylene (PP), polyethylene (PE), olefin elastomers, cyclic polyolefins, polymethylpentene, etc., from the viewpoint of economic efficiency, and particularly preferably a transparent member or translucent material having excellent moisture permeation resistance. It is desirable to use a member made of an olefinic thermoplastic resin that has visibility and is made of a member.

Particularly, in order to prevent solvent volatilization and moisture absorption of the ink contained in the ink container for a writing instrument of the present invention, a linear olefin resin which is preferably filled in the rear end of the ink and is not affected by the ink follower described later. It is preferable to use polypropylene or polyethylene as described above as the inner layer (first layer), and the second layer and other layers other than that are preferably made of another system such as olefinic thermoplastic resin.

Examples of the olefin resin of another system include linear olefin resin compounded with an inorganic filler, polymethylpentene, and cyclic olefin. In particular, a cyclic olefin resin is preferable from the viewpoint of suppressing moisture absorption of the ink solvent. Examples of the cyclic olefin-based resin include a cyclic olefin copolymer that combines the performance of a polyolefin resin having excellent visibility (light transmittance of 90% or more) and an amorphous resin, specifically, A
PL (Apel) series (APL6509T, APL6
013T, APL6011T, APL6015T, AP
L8008F, APL8009T, APL5014D
P or more, manufactured by Mitsui Chemicals, Inc.), or a type of amorphous polyolefin whose main raw material is dicyclopentadiene in a C5 fraction, and a cyclic olefin resin having excellent visibility (light transmittance of 90% or more), Specific examples thereof include Zeonex and Zeonea (manufactured by Zeon Corporation).

Examples of the inorganic filler used in the above linear olefin resin compounded with an inorganic filler include scaly mica, fine titanium particles, fine silica particles, and calcium carbonate. The average particle size of these inorganic fillers is preferably 0.5 to 50 μm, from the viewpoints of improved dispersibility and steric hindrance of the permeation substance.
More preferably, the thickness is 0.5 to 30 μm. In addition, the resin layer filled with this inorganic filler may reduce transparency due to its thickness and filling amount, so care must be taken in balance with performance, and the amount of the inorganic filler blended is , In the resin layer.
It is desirable to mix it in an amount of 01 to 20% by weight.

Further, the adhesion between the layers formed of these resins can be improved without using an adhesive layer for the purpose of adhesion.
It can be formed only by the affinity of the thermoplastic resin such as the above-mentioned olefin resin. This is because, for example, in the thermoplastic resin A and the thermoplastic resin B, an interface between the resins is formed, but the thermoplastic resin A and the thermoplastic resin B can be brought into contact with each other with an affinity mainly due to Van der Waals force. Further, since the thermoplastic resin A and the thermoplastic resin A + inorganic filler are extruded by the same resin, the interface is melted and the layer of the inorganic filler is oriented. Although it is preferable that there is no interface as much as possible, the presence of an adhesive layer under high humidity conditions results in further deterioration of the layers due to the solvent used in the present invention and the moisture entering from the outside,
The transparency of the resin is lost and the phenomenon of white turbidity occurs. Also, if an adhesive layer is inserted between the resins, the cost will be worse.

In the present invention, examples of the laminated structure which does not have an adhesive layer extruded from two or more thermoplastic resins include a two-layer structure, a three-layer structure, a four-layer structure and a five-layer structure. , A two-layer structure composed of thermoplastic resins having different properties for the inner layer and the outer layer, a thermoplastic resin for the inner layer, a thermoplastic resin having different properties from the thermoplastic resin of the inner layer for the middle layer, and a thermoplastic resin having the same properties as the inner layer for the outer layer Alternatively, the outer layer has a three-layer structure composed of a thermoplastic resin having different properties from the thermoplastic resin of the inner layer and the middle layer, a four-layer structure of the first layer (inner layer) to the fourth layer (outermost layer), and adjacent layers are respectively Examples include thermoplastic resins having different characteristics. Preferably, in order to further exert the effect of the present invention, a cyclic olefin resin layer having the above characteristics, a laminated structure composed of a linear olefin resin compounded with an inorganic filler is preferable, for example, in the case of a two-layer structure Is preferably provided in the outermost layer, in the intermediate layer in the case of a three-layer structure, and in the case of four or more layers, provided in one or more between the outermost layer and the innermost layer, or in the outermost layer.

In the present invention, these resin layers are combined with the thickness (L1, L2, L3 ...) Of each resin layer in a laminated structure having no adhesive layer extruded from two or more thermoplastic resins. The total thickness (L) is the ink type
Although it varies depending on the type of thermoplastic resin used and the like, it is preferable that the total thickness (L) is 0.05 to 2.
It is preferable that the thickness (L1, L2, L3 ...) Of each of the thermoplastic resin molecular layers is 0.05 to 1.8 mm.

The main solvent of the ink for a writing instrument housed in the ink container for a writing instrument of the present invention is at least one selected from alcohols having 4 or more carbon atoms in the molecule, polyhydric alcohols and glycol monoethers. Specific examples of alcohols that can be used are aliphatic alcohols having 2 or more carbon atoms, and n-butanol, isobutanol, tert-butyl alcohol, 1-pentanol, isoamyl alcohol, sec-amyl alcohol, 3 -Pentanol, tert-amyl alcohol, n-hexanol, methylamyl alcohol, 2-ethylbutanol,
n-hebutanol, 2-hebutanol, 3-hebutanol, n-octanol, 2-octanol, 2-ethylhexanol, 3,5,5-trimethylhexanol,
Examples thereof include nonanol, n-decanol, undecanol, n-decanol, trimethylnonyl alcohol, tetradecanol, hebutadecanol, cyclohexanol, 2-methylcyclohexanol, benzyl alcohol and various other higher alcohols.

The polyhydric alcohols include, for example, diethylene glycol, 3-methyl-1,3-butanediol, triethylene glycol, dipropylene glycol, 1,3-butanediol and 1,5-pentanediol. Examples thereof include polyhydric alcohols having 2 or more carbons and 2 or more hydroxyl groups in the molecule such as xylene glycol and octylene glycol. Further, as the glycol monoether, for example, butyl ether, hexyl ether, 2-ethylhexyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-
Ethyl butyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, 3-methyl-3-methoxy-1-butanol , 3-
Methoxy-1-butanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol phenyl ether, propylene glycol tertiary butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl Examples thereof include ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, and tetrapropylene glycol monobutyl ether. Among the above-mentioned solvents, particularly preferable are solvents other than the ethylene glycol derivative from the viewpoints of safety and oral toxicity. The content of these solvents is 2 with respect to the total amount of ink.
It is 0 to 80% by weight.

The ink composition for a writing instrument to be contained in the ink container for a writing instrument of the present invention contains, in addition to the main solvent, a pigment (including a resin pigment), a coloring agent such as a dye, a resin, and an ink for a writing instrument. And optional components. As an optional component contained in the ink for writing instruments, for example,
Examples thereof include a rust preventive agent, a fungicide, a surfactant, a lubricant and a wetting agent which are compatible with each other without adversely affecting the ink. In particular, fatty acids and the like can be preferably used as the lubricant. In addition, a non-volatile solvent that is compatible with the main solvent may be contained as an additive for suppressing drying in a range that does not adversely affect the product characteristics.

When the ink composition for a writing instrument according to the present invention is used in a ballpoint pen, it is preferable to provide an ink follower at the rear end of the ballpoint pen. Since the above-mentioned solvent used in the present invention is volatile, the ink follower is used for preventing volatilization, hygroscopicity and ink leakage.
The ink follower used must have low permeability and low diffusivity with respect to the solvent used for the ink, and its base is a non-volatile or hardly volatile fluid, specifically polybutene or liquid paraffin. For example, non-silicon type oils and fats which are basically incompatible with the solvent having the above characteristics used in the present invention can be used. When the viscosity of these substances is low, it is preferable to use a thickener or a gelling agent. Specific examples thereof include metal soaps, bentonites, fatty acid amides, hydrogenated castor oils, metal fine particles containing titanium oxide, silica, alumina and the like, celluloses, elastomers and the like.

Next, a specific embodiment of the ink containing member for a writing instrument of the present invention will be described in more detail with reference to FIGS. 1 and 2. 1 (a), 1 (b) and 2 show a case where the ink container for a writing instrument of the present invention is applied to an ink container for a ballpoint pen (refill). The ink container A for writing instruments according to the present embodiment has an ink container 11 having a ball-point pen type tip 10 at its tip. In addition, 12 is an ink for a ball-point pen containing a solvent having the above-mentioned characteristics, which is filled in the ink containing tube, 13 is a joint member between the pen tip portion and the ink containing tube, and 14 is an ink follower. The ink containing tube 11 is formed by coextrusion molding, and as shown in FIG. 1B, the inner layer portion 11 made of the above-mentioned thermoplastic resin, in this embodiment, is made of PP for the inner layer and the outermost layer, respectively.
a, 11c (each having a thickness of 0.2 mm), and an intermediate layer 11b (having a thickness of 0.6 mm) 11b made of a cyclic olefin resin between the inner layer 11a and the outer layer 11c. As shown in FIG. 2, the ink containing member A for a writing instrument is attached to a ball-point pen shaft body 15 and used as a ball-point pen. In addition, 16 is a tail plug, 17 is a cap body, 1
8 is a seal rubber.

The ink container for a writing instrument according to the present invention having the above-described structure can be sufficiently satisfied with respect to the above-mentioned solvent permeability and moisture absorptivity even under various environments. The reason why the ink is excellent in storability over time is presumed to be due to the following reasons. The reason why such an effect is exhibited is that the interaction between the ink solvent used and the molding resin has a great influence. That is,
Alcohols having 4 or more carbon atoms in the molecule, polyhydric alcohols, and glycol monoethers are organic solvents having a strong hygroscopic property, and therefore have the action of plasticizing the ink containing tube material used, In this case, moisture permeation from the outside of the accommodating pipe becomes severe under high temperature and high humidity conditions. Therefore, it is necessary to select a material having a low affinity for these solvents, and as a result, a thermoplastic resin, preferably,
It has been found that olefinic resins that are not linear are preferred. Further, it must have resistance to a base oil used for an ink follower used for preventing ink volatilization and the like. Therefore, it is desirable to protect the inner layer with a thermoplastic resin, preferably a linear olefin resin, which is resistant to the base oil used for the ink follower and the like. The second and subsequent layers are laminated with a thermoplastic resin having different characteristics from that of the inner layer, preferably a compound in which a cyclic olefin or an inorganic filler is compounded to suppress the hygroscopicity of the ink solvent and to withstand the ink follower. It is possible to manufacture an ink containing tube (tube) having Further, since the thermoplastic resin made of these olefinic resins has a transparent feeling, the transparent feeling is not lost even if the laminated structure is formed by extrusion molding, and there is no inconvenience that the remaining ink amount cannot be confirmed. From these facts, by adopting the ink storage tube structure of the present invention, it is possible to obtain sufficient permeation resistance and moisture absorption resistance even with respect to solvent permeation and moisture absorption under various environments. An ink storage tube for a writing instrument that has excellent storability of ink over time is provided.

[0023]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 8 and Comparative Examples 1 to 20] (1) Ink for evaluation (4 types) having the following composition used in each of Examples and Comparative Examples (4 types): 1 to 4 were prepared, and Ink storage tube (7
Species): 1-7 were prepared. (Evaluation ink: 1) Colorant: Spiron Black GMH Special 5% (Hodogaya Chemical Co., Ltd.) Colorant: Varifast Violet # 1702 23% (Orient Chemical Co., Ltd.) Resin: Polyvinyl butyral BM-1 (Sekisui) Chemical Co., Ltd.) 4% Resin: YP90L (Yasuhara Chemical Co., Ltd.) 8% Solvent: 3-Methoxybutanol 35%: 3-Methoxy-3-methyl-1-butanol 25%

[0025] (Evaluation ink: 2) Coloring Agent: Varifast Violet # 1702 26%         (Made by Orient Chemical Industry) Resin: Polyvinyl butyral BM-1 (manufactured by Sekisui Chemical Co., Ltd.) 4%     : Hirac 110H (Hitachi Chemical Co., Ltd.) 10% Solvent: Hexylene glycol 10% Solvent: 3-methoxy-3-methyl-1-butanol 50%

[0026] (Evaluation ink: 3) Colorant: Spyron Yellow C-GNH (Hodogaya Chemical Co., Ltd.) 20% Resin: Polyvinyl butyral BM-S (manufactured by Sekisui Chemical Co., Ltd.) 8% Resin: Hirac 110H (Hitachi Chemical Co., Ltd.) 12% Solvent: ethanol 60%

[0027] (Evaluation ink: 4) Coloring agent: Spiron Yellow C-GNH (Hodogaya Chemical Co., Ltd.) 10% Resin: Becca Site 1111 (Hitachi Chemical Co., Ltd.) 30% Solvent: dipropylene glycol dimethyl ether 60%

(Preparation of Ink Storage Tube) An extrusion molding machine (multilayer extrusion die, 2 types 2 layers, 3 types 3 layers, 5 types 5 layers, etc.) is formed by using each of the thermoplastic resins described in 1 to 7 below. Was extruded into a cylindrical shape having an inner diameter of 4.0 mm and a thickness of 1.0 mm and cut into a length of 100 mm to prepare an ink containing tube having a cylindrical laminated structure or a single layer structure. 1. First layer (inner layer) / second layer (intermediate layer) / third layer (outer layer) = polypropylene (0.3 mm) / polypropylene 1% by weight filler of flake-shaped mica having an average particle size of 2 to 5 μm (0.3 mm ) / Polypropylene (0.4 mm) 2. First layer (inner layer) / second layer (outer layer) = polypropylene (0.4 mm) / cyclic olefin (Apel 8008T,
Mitsui Chemicals, 0.6 mm) 3. First layer (inner layer) / second layer (intermediate layer) / third layer (outer layer) = polypropylene (0.3 mm) / Polypropylene 1% by weight titanium fine particles with an average particle size of 0.5 to 2 μm (0. 3 mm) / polypropylene (0.4 mm) 4. First layer (inner layer) / second layer (intermediate layer) / third layer (outer layer) = polyethylene (0.2 mm) / cycloolefin (Apel 8009T, Mitsui Chemicals, 0.6 mm) / polyethylene (0.2 mm) ) 5. Polypropylene 6. ABS resin 7. First layer (inner layer) / second layer / third layer / fourth layer / fifth layer (outermost layer) = polypropylene (0.2 mm) / adhesive layer (maleic anhydride modified polyolefin, 0.2 mm) /
Nylon (Novamid 1020 Mitsubishi Chemical Co., 0.2
mm) / adhesive layer (maleic anhydride modified polyolefin,
0.2mm) / Polypropylene (0.2mm)

(2) Preparation of ink container tube for ballpoint pen)
A tip of a ball-point pen having a ball diameter of 1.0 mm was attached to the tip of each ink containing tube obtained by the above method with a joint member made of metal (brass), and the ink for evaluation of the above composition (4 types): 1 to 4 Was charged in a predetermined amount (1.0 g).
Tables 1 to 3 below show combinations of the above-described evaluation inks and ink-accommodating tubes, which are examples and comparative examples. Thereafter, a predetermined amount (0.15 g) of an ink follower having the following composition was further filled from the rear end of each ink containing tube filled with each evaluation ink to obtain an ink containing tube sample for an oil-based ballpoint pen.

(Compound composition of ink follower) Diana Process Oil PW-380 (made by Idemitsu Kosan Co., Ltd.) 100% by weight
It was used. The pen body was left still with the pen tip down so that the ink follower did not leak.

Using the samples of the ink container tubes for oil-based ballpoint pens obtained in the above Examples and Comparative Examples, the moisture absorption rate, the transmittance, and the change of the container container were evaluated by the following methods. The results of these evaluations are shown in Tables 1 to 3 below.

(Evaluation method) The film was allowed to stand for 2 weeks in an environment of a temperature of 50 ° C., a humidity of 30% and a humidity of 80%, and the moisture absorption rate and the transmittance in the ink containing tube were measured and calculated. Also, changes in appearance were observed. The moisture absorption rate is measured by measuring the amount of water in the ink with a Karl Fischer moisture meter (MKA- manufactured by Kyoto Electronics Manufacturing Co., Ltd.).
210) and the moisture content was calculated as the moisture absorption rate from the difference from the blank. Further, the transmittance was calculated by correcting the amount of change in the ink filling amount and the water content, and calculated as the ink transmittance.

(Evaluation of Moisture Absorption Rate of Ink Storage Tube) The degree of moisture absorption rate was evaluated according to the following evaluation criteria. Evaluation Criteria: A: Moisture absorption of 1.00% or less O: Moisture absorption of 1.00 to 1.50% B: Moisture absorption of 1.50 to 2.00% X: Moisture absorption of 2.00% More than

(Evaluation of transmittance of ink containing tube) The degree of transmittance was evaluated according to the following evaluation criteria. Evaluation criteria: ⊚: Transmittance of 1.00% or less ○: Transmittance of 1.00 to 1.50% Δ: Transmittance of 1.50 to 2.00% ×: Transmittance of 2.00% More than

(Evaluation of Change in Ink Storage Tube Container) 50
After being left for 2 weeks in an environment of 80 ° C. and 80 ° C., the sample was visually deteriorated, but was evaluated according to the following evaluation criteria. Evaluation criteria: ◯: The appearance did not change at all. Δ: Cracks, white turbidity, or deformation observed in the appearance (low degree). X: Cracks, white turbidity, or deformation observed on the appearance (mostly).

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

As is clear from the results shown in Tables 1 to 3, the ink containing tubes of the combinations of Examples 1 to 8 which fall within the scope of the present invention are the same as those of Comparative Examples 1 to 20 which fall outside the scope of the present invention. It was found that the solvent hygroscopicity and solvent permeability were extremely superior to the combination. In addition, each of the ink containing tubes of Examples 1 to 8 which is within the scope of the present invention does not have a crack, a cloudy state, or a deformed appearance even when left for two weeks in an environment of 50 ° C. and 80%, and has a good visibility. Also proved to be excellent.

[0040]

EFFECTS OF THE INVENTION According to the present invention, even under a wide variety of environments, it has sufficient permeation resistance and moisture absorption resistance with respect to the permeability of solvents and the moisture absorption of water. Provided is an ink storage tube for a writing instrument, which has excellent storability.

[Brief description of drawings]

FIG. 1 (a) is a vertical cross-sectional view showing, in a cross-sectional aspect, an example in which the ink containing member for a writing instrument of the present invention is applied to an ink containing tube for a ballpoint pen, and FIG. 1 (b) is a partial cross-section showing a main part thereof. It is a side view.

FIG. 2 is a vertical cross-sectional view of a ballpoint pen including the ink container tube for the ballpoint pen of FIG.

[Explanation of symbols]

11 Ink storage tube 11a thermoplastic resin layer 11b thermoplastic resin layer 11c thermoplastic resin layer

Claims (4)

[Claims] 1. An ink container for a writing instrument, containing an ink containing a solvent selected from alcohols having 4 or more carbon atoms in the molecule, polyhydric alcohols, glycol monoethers, the writing instrument. An ink container for a writing instrument, wherein the ink container for ink has a laminated structure extruded from two or more kinds of thermoplastic resins and having no adhesive layer. 2. The ink container for a writing instrument according to claim 1, wherein the thermoplastic resin is an olefin resin. 3. The thermoplastic resin is an olefin-based resin having visibility.
Ink storage tube for the writing instrument described. 4. The ink follower for preventing solvent evaporation and moisture absorption of the writing instrument ink at the rear end of the writing instrument ink storage tube. Ink storage tube for writing instruments.