JP2007076329A - Anti-backflow agent and writing instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-backflow agent which can bring about sufficient airtight stopper properties against a coating liquid using a low-polarity solvent such as a hydrocarbon-based solvent, and which can maintain sufficient anti-backflow properties over a long period of time by having excellent flow resistance and resistance to moisture absorption, while sufficiently suppressing the volatilization of the anti-backflow agent itself. <P>SOLUTION: This anti-backflow agent is used for preventing the coating liquid from flowing out of a storage vessel in which the coating liquid is stored. Characteristically, the anti-backflow agent contains a thickener, and a polyoxyalkylenealkyl glucoside which is composed of a 2C or 3C alkylenoxide and a 1C or 2C alkyl group. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a backflow preventive agent used for preventing a coating liquid from flowing out of a container in which the coating liquid is stored in a writing instrument such as a ballpoint pen, a sign pen, a marker, a correction tool, and the like. Related to writing instruments.

  As a writing instrument such as a ballpoint pen or a correction pen, a coating liquid such as ink is accommodated in a container, and in order to prevent the coating liquid from flowing out (reverse flow) from the container, Those having a configuration in which a backflow preventive agent such as grease is accommodated are widely used.

  The functions required for the above-mentioned anti-backflow agent are to prevent the flowable coating liquid from flowing out by covering with a non-flowable anti-backflow agent in the natural state (outflow prevention property) and not to dry up the coating liquid. (Seal plugging), and following the consumption of the coating solution without making a gap at the end of the coating solution, and scraping the coating solution so that the coating solution does not remain on the wall in the container (following property) Can be mentioned. In order for the backflow preventive agent to fully perform these functions, it is necessary that the backflow preventive agent does not mix with the coating liquid, and for the convenience of manufacturing the writing instrument, the viscosity of the backflow preventive agent and the coating liquid It is necessary that the specific gravity difference is appropriate.

  By the way, the backflow preventive agent is usually composed of a base oil and a thickener, and the backflow preventive agent used for ballpoint pens and the like is based on mineral oil, polybutene, silicon oil or the like. It is general (see, for example, Patent Document 1).

  Here, since mineral oil, polybutene, and silicone oil are oleophilic (hydrophobic), the backflow preventive agent using these base oils is hermetically sealed against a coating solution using a highly polar solvent such as water. Sex can be obtained. However, this anti-backflow agent prevents the base oil and the coating solution from being mixed with each other over time in coating solutions that use lipophilic solvents with low polarity such as hydrocarbon solvents. Since the solvent is volatilized through the agent, there is a problem that sufficient sealing performance cannot be obtained.

  Therefore, in order to improve such a problem, a backflow preventer using a hydrophilic substance that is incompatible with the coating solution, such as glycerin or polyalkylene glycol, as a base oil has been proposed (for example, see Patent Documents 2 and 3). ).

Utility Model Registration No. 3050699 JP 2000-343875 A JP 2002-103884 A

  According to the backflow preventive agent using the hydrophilic base oil as described in Patent Documents 2 and 3, the base oil is used for a coating solution using a low polarity solvent such as a hydrocarbon solvent. And the coating solution can be prevented from being compatible with each other, and the sealing property can be obtained. However, since hydrophilic substances such as glycerin and polyalkylene glycol absorb moisture in the air, the backflow preventive agent decreases in viscosity as the amount of moisture absorption increases, and the function of preventing the coating liquid from flowing out over time. Decreases, and a problem of leakage of the coating liquid occurs.

  Patent Document 3 discloses a configuration in which a drying prevention body is further provided to prevent the backflow preventive agent itself from drying and volatilizing. However, when a drying prevention body is further provided, it is necessary to arrange two types of greases, that is, a backflow prevention agent and a drying prevention body in order at the rear end of the coating solution. In order to arrange the coating liquid, the backflow preventive agent, and the anti-drying body in a predetermined position in the container without being mixed or replaced with each other, the specific gravity and viscosity of each are adjusted with extremely high accuracy. In addition, the process for filling the container with the anti-drying body must be increased. Under such circumstances, it is not necessary to further provide an anti-drying body, and there is a demand for the development of a backflow preventing agent having good characteristics alone.

  The present invention has been made in view of the above-mentioned problems of the prior art, and can provide a sufficient sealing property for a coating solution using a low polarity solvent such as a hydrocarbon solvent, and can prevent backflow. An object of the present invention is to provide a backflow preventive agent that has excellent flow resistance and moisture absorption resistance and can maintain sufficient outflow prevention properties for a long period of time while sufficiently suppressing volatilization of the agent itself.

  In order to achieve the above object, the present invention is a backflow preventer used for preventing the coating liquid from flowing out of the container in which the coating liquid is stored, wherein the alkylene oxide has a carbon number of Provided is a backflow prevention agent comprising a polyoxyalkylene alkyl glucoside having 2 or 3 and an alkyl group having 1 or 2 carbon atoms and a thickener.

  By using the polyoxyalkylene alkyl glucoside as a base oil, the backflow preventive agent of the present invention can exhibit a sufficient sealing performance against a coating solution using a low polarity solvent such as a hydrocarbon solvent. In addition, since it is harder to absorb moisture than the conventional anti-backflow agent using diglycerin or the like as a base oil and there is no fluidity in the natural state, sufficient outflow prevention can be maintained for a long time. In addition, according to the backflow preventive agent of the present invention, sufficient followability with the consumption of the coating liquid can be obtained, and the backflow preventive agent does not flow due to impact such as dropping, and further, as a writing instrument over a long period of time. Stable quality can be maintained.

  In the backflow preventive agent of the present invention, the polyoxyalkylene alkyl glucoside is preferably polyoxyethylene methyl glucoside. By using polyoxyethylene methyl glucoside as a base oil, the backflow preventive agent can obtain better sealing performance while maintaining sufficient moisture absorption resistance.

  In the backflow preventive agent of the present invention, the average added mole number of the alkylene oxide in the polyoxyalkylene alkyl glucoside is preferably 5 to 30 mol. By using such a polyoxyalkylene alkyl glucoside as a base oil, the backflow preventive agent can obtain more sufficient sealing performance and more sufficient moisture resistance.

  Furthermore, in the backflow preventive agent of the present invention, the content of the polyoxyalkylene alkyl glucoside is preferably 45.0 to 99.8% by mass based on the total amount of the backflow preventive agent. When the content of the polyoxyalkylene alkyl glucoside in the backflow preventive agent is within the above range, the backflow preventive agent can obtain more sufficient sealing performance and more sufficient moisture absorption resistance and flow resistance.

  The present invention also provides a coating liquid, a container that stores the coating liquid, a coating unit that is attached to one end of the container and controls the discharge of the coating liquid, and the coating liquid in the container. Provided is a writing instrument comprising, on the opposite side to the application part side, the backflow preventive of the present invention accommodated adjacent to the application liquid. The applicator of the present invention is particularly effective when the coating solution contains a hydrocarbon solvent.

  According to the writing instrument of the present invention, since the anti-backflow agent of the present invention described above is provided, even when a low-polar solvent such as a hydrocarbon solvent is used for the coating liquid, the coating liquid is sufficient. While being able to obtain a sealing plug, the anti-backflow agent exhibits excellent moisture absorption resistance and flow resistance, and can maintain sufficient anti-outflow properties for the coating liquid for a long period of time. Further, in the writing instrument of the present invention, sufficient followability of the backflow preventive agent with respect to the coating liquid can be obtained, and the backflow preventive agent does not flow due to an impact such as dropping, and the quality of the writing instrument is stabilized over a long period of time. Can be kept in.

  According to the present invention, it is possible to obtain a sufficient sealing performance with respect to a coating solution using a low-polar solvent such as a hydrocarbon solvent, and it has excellent moisture absorption resistance and sufficient outflow prevention properties. A backflow preventing agent that can be maintained for a long period of time and a writing instrument using the same can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

(Backflow prevention agent)
The backflow preventive agent of the present invention is a backflow preventive agent used for preventing the coating liquid from flowing out of the container in which the coating liquid is stored, and the alkylene oxide has 2 or 3 carbon atoms. And a polyoxyalkylene alkyl glucoside having 1 or 2 carbon atoms in the alkyl group, and a thickener. Hereinafter, each component which comprises the backflow preventive agent of this invention is demonstrated.

  Polyoxyalkylene alkyl glucoside is used as a base oil. As such polyoxyalkylene alkyl glucoside, one or two alkylene oxides selected from ethylene oxide (EO) and propylene oxide (PO) are used. Those added to alkyl glucosides can be used. Alkylene oxide, which has more carbon atoms than propylene oxide, has higher affinity with hydrocarbon solvents as the number of carbon atoms increases. Therefore, when used as a base oil for backflow preventives, hydrocarbon solvents in the coating solution Is volatilized, and sufficient sealing performance cannot be obtained.

［式（１）中、Ｘは２又は３を示し、Ｙは１又は２を示し、ａ、ｂ、ｃ及びｄはａ＋ｂ＋ｃ＋ｄが１以上となるように選ばれる０以上の整数を示す。］ The polyoxyalkylene alkyl glucoside is represented by the following general formula (1).

[In the formula (1), X represents 2 or 3, Y represents 1 or 2, and a, b, c and d represent an integer of 0 or more selected so that a + b + c + d is 1 or more. ]

  The alkylene oxide in the polyoxyalkylene alkyl glucoside needs to be ethylene oxide or propylene oxide, and is preferably ethylene oxide. Moreover, it is preferable that the average added mole number of these alkylene oxides is 5-30 mol, and it is more preferable that it is 10-20 mol.

  The alkyl group in the polyoxyalkylene alkyl glucoside needs to be a methyl group or an ethyl group, and is preferably a methyl group.

  Specifically as a polyoxyalkylene alkyl glucoside, MACBIOBIDE MG-10E, MG-20E, MG-10P, MG-20P (above, Nippon Oil & Fats Co., Ltd. product) etc. are mentioned as a commercial item.

  Among these polyoxyalkylene alkyl glucosides, polyoxyethylene methyl glucoside is particularly preferable. By using this as a base oil, the backflow preventive agent can obtain more sufficient sealing performance and moisture absorption resistance.

  In the backflow preventive agent of the present invention, the polyoxyalkylene alkyl glucoside can be used alone or in combination of two or more.

  The content of the polyoxyalkylene alkyl glucoside in the backflow preventing agent is preferably 45.0 to 99.8% by weight, more preferably 65.0 to 97.0% by weight, based on the total amount of the backflow preventing agent. Preferably, it is 85.0-95.0 mass%. When this content is less than 45.0% by mass, the sealing performance tends to be lower than when the content is within the above range, and when it exceeds 95.0% by mass, the content is within the above range. As compared with the case of the above, the viscosity becomes lower and the outflow prevention property of the coating liquid tends to be lowered.

  The backflow preventive agent of the present invention may contain the above-mentioned polyoxyalkylene alkyl glucoside alone as the base oil, but other groups other than the polyoxyalkylene alkyl glucoside as long as the effects of the present invention are not impaired. Oil may further be included. As the other base oil, a known base oil used for a conventional backflow preventive agent (grease) can be used without particular limitation. Such other base oils include polybutene, silicone oil, mineral oil, glycerin, diglycerin, polyglycerin, polyethylene glycol, polypropylene glycol, phenyl glycol, alkylene glycol alkyl ether, polyglycerin fatty acid ester, alkylene oxide adduct of glycerin. , An alkylene oxide adduct of diglycerin, an alkylene oxide adduct of polyglycerin, and the like. The content of the other base oil in the backflow preventive agent is preferably 30% by mass or less, more preferably 15% by mass or less, based on the total amount of the backflow preventive agent.

  The thickener is not particularly limited, but for example, calcium soap, calcium composite soap, sodium soap, aluminum soap, aluminum composite soap, lithium soap, lithium soap, and other metal soap thickeners, urea compounds, Examples thereof include organic thickeners such as sodium terephthalate and polytetrafluoroethylene, and organic bentonite and inorganic thickeners such as silica gel. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the thickener in the backflow preventive agent is preferably 0.1 to 50.0% by weight, more preferably 3.0 to 35.0% by weight, based on the total amount of the backflow preventive agent, It is especially preferable that it is 5.0-15.0 mass%. When the content is less than 0.1% by mass, the viscosity is lower than that when the content is within the above range, and the outflow prevention property of the coating solution tends to be reduced. When the content exceeds V, the sealing performance tends to be lower than when the content is within the above range.

  Further, the type and content of the thickener in the backflow preventive agent are such that the viscosity of the backflow preventive agent is 50,000 to 200,000 mPa · s, and the “consistency number” defined in JIS K2220 is No. 1, No. 2, It is preferable to adjust so as to be No. 3 or No. 3. Here, the viscosity of the backflow preventive agent can be measured using a Brookfield E-type viscometer under the conditions of temperature: 20 ° C. and rotation speed: 0.5 rpm. When the consistency and viscosity of the backflow preventive agent are within the above ranges, the functions required for the backflow preventive agent such as sealing ability, outflow prevention ability and followability can be achieved at a high level.

  The backflow preventive agent of the present invention further contains additives such as a structural stabilizer, an antioxidant, a surface treating agent, a colorant, a surfactant, and a thickener in addition to the above-described base oil and thickener. May be.

  The backflow preventive agent of the present invention is, for example, added to a base oil with a thickener and other additives as required, heated as necessary, mixed well, and then passed through a three-roll mill at room temperature. Can be adjusted and manufactured. The backflow preventing agent thus obtained can be used, for example, in a liquid state, a gel state, or a state in which these are impregnated in a sponge-like porous body. Moreover, you may accommodate a backflow prevention agent in a container with the solid substance which consists of plastic materials etc.

(Writing instrument)
FIG. 1 is a schematic cross-sectional view showing an embodiment of the writing instrument of the present invention. In the writing instrument 100 shown in FIG. 1, the coating liquid 12 is stored in a container 14, and an application unit 20 is attached to one end of the container 14. The application unit 20 includes a joint 22, a ball holder 24, and a ball 26, and is fixed to the container 14 by the joint 22. Moreover, the backflow preventive agent 16 of the present invention described above is accommodated in the container 14 on the side opposite to the application part 20 side of the application liquid 12 in a state adjacent to the application liquid 12. Here, the backflow preventing agent 16 is arranged so that no gap is formed between the coating solution 12 and the backflow preventing agent 16.

  Further, in the writing instrument 100, the core 10 is configured by the container 14, the coating unit 20, the coating liquid 12, and the backflow preventive agent 16, and the core 10 is attached to the main body shaft 18. A tail plug 28 having a vent hole is attached to the rear end (one end opposite to the application unit 20).

  Hereinafter, although the component of the writing instrument 100 is demonstrated, the general structure used for writing instruments, such as a ball-point pen, can be applied to structures other than the backflow prevention agent 16 in the writing instrument 100 of this invention.

  As the coating liquid 12, ink such as water-based ink, oil-based ink, and correction liquid can be used. Here, in the case where the coating liquid 12 contains a low polarity solvent such as a hydrocarbon solvent, by using the backflow preventive agent 16 of the present invention, a sufficient sealing performance can be obtained, and the backflow preventive agent 16 is Since it absorbs less moisture and has excellent flow resistance, it can maintain sufficient anti-outflow properties for a long period of time. Further, the backflow preventive agent 16 can obtain sufficient followability with respect to the coating liquid 12, and can suppress the backflow preventive agent 16 from flowing due to an impact such as a drop of the writing instrument 100, and further, for a long time. Thus, the state of the coating liquid 16 can be kept stable.

  Here, examples of the hydrocarbon solvent used in the coating liquid 12 include n-hexane, n-heptane, n-octane, isooctane, methylcyclohexane, ethylcyclohexane, decane, cyclohexane, toluene, xylene, and the like. . These hydrocarbon solvents are mainly used as solvents for correction fluids, and the effects of the present invention described above can be effectively obtained in writing instruments using such solvents. In addition, the backflow preventive agent of the present invention is not limited to the use of the backflow preventive agent for the coating solution using a low polarity solvent such as a hydrocarbon solvent, and can also be used as a backflow preventive agent for an aqueous coating solution. . At that time, it is important to adjust the viscosity of the backflow preventing agent and the specific gravity difference between the coating solution and the backflow preventing agent so that the backflow preventing agent does not settle in the coating solution.

  The container 14 corresponds to an ink tank in a ballpoint pen, and may be made of nylon, polyacetal, polycarbonate, or the like. Further, the shape of the container 14 is not particularly limited, and may be a cylindrical shape, for example.

  As the main body shaft 18 and the tail plug 28, for example, those made of a plastic material such as polypropylene can be used.

  As the joint 22, for example, a material made of nylon, polyacetal, polycarbonate, or the like can be used.

  The application unit 20 corresponds to a ballpoint pen tip in a ballpoint pen. As the joint 22, the ball holder 24, and the ball 26, those used in a normal ballpoint pen can be used.

  The writing instrument 100 of the present invention having the above-described configuration can be manufactured by a manufacturing method such as a normal ballpoint pen. That is, first, after applying the application part 20 to the container 14 and integrating them, the application liquid 12 is filled from the opening on the container 14 opposite to the application part side, and then the backflow preventive agent 16 is added. The core 10 is produced by filling. Then, the writing instrument 100 can be manufactured by mounting the obtained core 10 on the main body shaft 18 and further attaching the tail plug 28 to the main body shaft 18.

  Although one embodiment of the writing instrument of the present invention has been described above, the writing instrument of the present invention is not limited to the above. For example, the writing instrument of the present invention may not have the main body shaft 18, and the container 14 may be the main body shaft as it is. Moreover, the application part 20 is not limited to a ball-point pen tip, For example, a felt tip etc. may be sufficient. Furthermore, the writing instrument of the present invention has a pressurizing mechanism that causes the coating liquid 12 and the backflow preventive agent 16 in the container 14 to be pressurized from the rear end (one end opposite to the coating unit 20) side. It may be a thing.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

[Examples 1-6 and Comparative Examples 1-2]
The materials shown in Table 1 below were blended in the blending amounts (unit: parts by mass) shown in the same table. At this time, other materials were added to the base oil. After fully mixing the obtained compound, it was adjusted by passing through a three-roll mill, and the backflow preventives (grease) of Examples 1 to 6 and Comparative Examples 1 and 2 were obtained.

The details of each material in Table 1 are as follows.
MACBIOBRIDE MG-10E: trade name, polyoxyethylene methyl glucoside, average number of moles of EO added 10, manufactured by NOF Corporation,
MACBIOBRIDE MG-20E: trade name, polyoxyethylene methyl glucoside, average number of added moles of EO 20, manufactured by NOF Corporation,
MACBIOBRIDE MG-10P: trade name, polyoxypropylene methyl glucoside, average number of moles of PO added 10, manufactured by NOF Corporation,
MACBIOBRIDE MG-20P: trade name, polyoxypropylene methyl glucoside, average added mole number of PO 20, manufactured by NOF Corporation,
Polybutene LV-100: trade name, polybutene, weight average molecular weight 970, manufactured by Nippon Petrochemical Co., Ltd.
Aerosil 200: trade name, silica gel, manufactured by Nippon Aerosil Co., Ltd.
Unilube: Trade name, poly (oxyethylene / oxypropylene) polyol, manufactured by NOF Corporation.

[Evaluation of sealability]
A nylon cylindrical ink tank (inner diameter: 4 mm) having a ballpoint pen tip at its tip was filled with 1.5 g of an ink composition containing 50% by mass of methylcyclohexane based on the total amount of the composition. Into this ink tank, 0.23 g of the backflow preventive agent of Examples 1 to 6 and Comparative Examples 1 and 2 was filled so as to be adjacent to the ink composition, the ink composition was sealed, and a sample for evaluating the sealing performance was prepared. Produced.

  The obtained sample is allowed to stand in an environment of 50 ° C. for 2 weeks, and the amount of decrease in the mass of the sample after being left with respect to the mass of the initial sample (the mass of the entire initial sample−the mass of the entire sample after being left) is obtained. It was. The results are shown in Table 2. Here, the decrease amount mainly indicates the volatilization amount of the solvent in the ink composition, and the smaller the value, the better the sealing performance. Moreover, if the amount of reduction is 30 mg or less, it can be determined that the sealing performance is good, and if it is 20 mg or less, it can be determined that the sealing performance is particularly good. Furthermore, if the amount of reduction is 30 mg or less, it can be determined that volatilization of the backflow preventive agent itself is sufficiently suppressed.

[Evaluation of moisture absorption resistance]
A nylon cylindrical ink tank (inner diameter 4 mm) equipped with a ballpoint pen tip is filled with 0.23 g of the backflow preventive agent of Examples 1 to 6 and Comparative Examples 1 and 2, and a sample for evaluating moisture absorption resistance Was made.

The obtained sample was left for 1 month in an environment of 25 ° C. and 60% RH with the pen tip facing upward, and the flow condition of the backflow preventive agent due to moisture absorption between the initial sample and the sample after being left. The presence or absence of the change was visually confirmed and evaluated according to the following evaluation criteria. The results are shown in Table 2.
A: The state before being left is kept (the back end of the backflow preventive agent is kept straight) (no problem),
B: Although not flowing out, the back end of the backflow preventive is inclined or recessed (no problem in practical use)
C: The backflow preventive agent has flowed out a little (there may be a practical problem),
D: The backflow preventive agent has flowed out of the ink tank (this is a practical problem).

[Evaluation of following]
In the same manner as the evaluation of the sealing performance, samples for evaluation of sealing characteristics using the backflow preventive agents of Examples 1 to 6 and Comparative Examples 1 and 2 were prepared. The sample for evaluation of hermetic plug performance was attached to the ballpoint pen main body shaft as a core to produce a ballpoint pen having a pressure mechanism.

Using the obtained ballpoint pen, writing was performed by hand writing until the ink composition disappeared, and the followability of the backflow inhibitor was evaluated. The followability is determined by whether the backflow preventive agent follows the rear end surface of the ink composition, whether the laydown is not lowered, and the backflow preventive agent does not remain on the inner wall of the ink tank. The evaluation items of whether or not the composition was scraped off were visually confirmed and evaluated according to the following evaluation criteria. The results are shown in Table 2.
A: The backflow preventive agent follows the rear end surface of the ink without creating a gap (no problem).
B: The backflow preventive agent remains slightly on the wall surface of the ink tank, but follows the rear end surface of the ink without creating a gap until the end (no problem in practical use).
C: The backflow preventive agent follows the rear end surface of the ink without forming a gap, but ink adhesion remains on the wall surface of the ink tank (this may cause a problem in practice).
D: The backflow preventive agent does not follow the rear end surface of the ink, thus hindering the discharge of the ink (which is a practical problem).

[Evaluation of impact flow resistance]
Ballpoint pens using the backflow preventing agents of Examples 1 to 6 and Comparative Examples 1 and 2 were produced in the same manner as in the followability evaluation.

The obtained ballpoint pen was dropped onto a concrete surface from a height of 1 m with the pen tip facing upward, the flow of the backflow preventive agent due to a drop impact was visually confirmed, and evaluated according to the following evaluation criteria. . The results are shown in Table 2.
A: The state before dropping is maintained (no problem),
B: The back end surface of the backflow preventive agent is slightly deformed, but no outflow occurs (no problem in practical use)
C: The rear end face of the backflow preventive agent is deformed and slightly flows out when left standing (may cause a practical problem),
D: The backflow preventive agent is deformed and flows out, and the ink also flows out (this is a problem in practice).

[Evaluation of storage stability]
Ballpoint pens using the backflow preventing agents of Examples 1 to 6 and Comparative Examples 1 and 2 were produced in the same manner as in the followability evaluation.

The obtained ballpoint pen is allowed to stand in an environment of 50 ° C. for 2 months. After visually confirming that the ink composition and the backflow preventive agent have not changed, whether or not writing is possible is confirmed. Evaluated according to. The results are shown in Table 2.
A: The state before being left is maintained and can be written without any problem (no problem).
B: The volume of the ink and the backflow preventive agent is slightly reduced, but writing is possible without any problem (no problem in practical use),
C: The volume of the ink and the backflow preventive agent is slightly reduced, a separation layer / precipitation is generated at the interface between the ink and the backflow preventive agent, and the ink discharge amount is slightly reduced although writing is possible. (May be a practical problem),
D: The backflow preventive agent is not tightly sealed, the volume of the ink and the backflow preventive agent is reduced, the ink is dried, and writing cannot be performed (problem is practically problematic).

  As is clear from the results shown in Table 2, according to the backflow preventive agent (Examples 1 to 6) of the present invention, compared with the backflow preventive agent of Comparative Examples 1 and 2, a hydrocarbon solvent (methylcyclohexane). It was confirmed that a sufficient sealing property can be obtained with respect to a coating solution using a), excellent moisture absorption resistance, and sufficient anti-outflow properties can be maintained for a long period of time. Moreover, according to the backflow preventive agent (Examples 1-6) of this invention, it was confirmed that all of followability, impact fluidity, and storage stability can be achieved.

It is a schematic cross section which shows one Embodiment of the writing instrument of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Center core, 12 ... Coating liquid, 14 ... Container, 16 ... Backflow prevention agent, 18 ... Main body axis | shaft, 20 ... Application | coating part, 22 ... Joint, 24 ... Ball holder, 26 ... Ball, 28 ... Tail plug, 100 ... writing instruments.

Claims (6)

A backflow preventing agent used for preventing the coating liquid from flowing out of the container in which the coating liquid is stored,
A polyoxyalkylene alkyl glucoside in which the carbon number of the alkylene oxide is 2 or 3, and the carbon number of the alkyl group is 1 or 2,
A thickener;
An anti-refluxing agent comprising:   The backflow preventive agent according to claim 1, wherein the polyoxyalkylene alkyl glucoside is polyoxyethylene methyl glucoside.   The backflow inhibitor according to claim 1 or 2, wherein an average addition mole number of the alkylene oxide in the polyoxyalkylene alkyl glucoside is 5 to 30 moles.   The content of the polyoxyalkylene alkyl glucoside is 45.0 to 99.8 mass% based on the total amount of the backflow preventive agent, according to any one of claims 1 to 3. Anti-backflow agent. A coating solution;
A container for containing the coating liquid;
An application unit attached to one end of the container for controlling the discharge of the application liquid;
The backflow preventive agent according to any one of claims 1 to 4, which is accommodated adjacent to the application liquid on the side opposite to the application part side of the application liquid in the container,
Writing instrument characterized by comprising. 6. The writing instrument according to claim 5, wherein the coating liquid contains a hydrocarbon solvent.

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