JP6454083B2 - Writing instrument refill and writing instrument with it - Google Patents

Description

  The present invention relates to a refill for a writing instrument that does not leak ink from the rear end of the refill for a writing instrument, and a writing instrument equipped with the refill.

  Conventionally, when using a ball-point pen, there is a problem that ink flows backward due to an impact such as writing with the tip upward or dropping accidentally, and this ink reversely leaks the ink to the outside and stains clothes and the like. In addition, in a so-called electronic pen used in a technique for storing and utilizing handwritten memos as electronic data as they are, the ink leakage due to the backflow of ink as described above causes a failure of internal electronic device components and the like.

  In view of these problems, there are many writing instruments that are equipped with an ink backflow prevention plug such as a polymer porous body or a fiber converging body as a plug for preventing ink leakage due to ink backflow behind the ink for ballpoint pens. Proposed.

  As a refill for ballpoint pens characterized in that an ink backflow prevention stopper is provided behind the ink for ballpoint pens, there are the following proposals. In Japanese Utility Model Publication No. 35-26916, “Ball Pen Inner” and Japanese Utility Model Publication No. 38-8251, “Ink backflow prevention device for ink storage tube or ink storage chamber of ballpoint pen”, the ink backflow prevention stopper is made of metal or natural rubber. In the case of using synthetic rubber or the like, in Japanese Utility Model Publication No. 45-6270 “ball pen ink backflow prevention device”, a sponge or the like is impregnated with a lubricant, and in Japanese Unexamined Patent Publication No. 2004-122604 “ink backflow prevention plug” A fiber bundle core is disclosed.

In addition, as a method for disposing the ink backflow prevention plug, a method of press fitting and mounting the ink backflow prevention plug is disclosed in Japanese Patent Application Laid-Open No. 1-210398 “Method for Pressing Foam into Tube”.
“Act No. 35-26916” "Act No. 38-8251" "Act No. 45-6270" "JP 2004-122604 A" "Japanese Patent Laid-Open No. 1-210398"

  However, if the ink backflow prevention plug is made of metal, natural rubber, synthetic rubber, or the like, and the sponge is impregnated with a lubricant as in Patent Documents 1 to 3, the ink containing cylinder is sealed from the outside. As a result, the air change is hindered and the ink followability is deteriorated. As a result, the handwriting is deteriorated, the writing quality is deteriorated, and further, the writing cannot be performed.

For this reason, Patent Document 4 discloses that a backflow prevention plug is formed by a fiber bundle core in consideration of ink followability. However, just examining the types of fibers constituting the ink backflow prevention plug by the fiber bundle core is not sufficient to prevent ink leakage due to the backflow of ink, and the method for processing the fiber bundle core and bundling it. It is important to consider the type of adhesive.
In addition, as disclosed in Patent Document 5, in the case of an ink backflow prevention stopper made of a conventional polymer porous body, in order to press-fit a cube or a rectangular parallelepiped formed larger than the inner diameter of the ink containing cylinder, The polymer porous body needs to be in a compressed state. When the polymer porous body is placed in the ink containing cylinder, it is difficult to be caught by the rear end surface of the ink containing cylinder and the assemblability is complicated.

  An object of the present invention is to provide a refill for a writing instrument that is free from ink leakage due to ink backflow and has good ink followability, and a writing instrument equipped with the refill.

In order to solve the above problems, the present invention provides:
"1. A writing body is attached to the tip of the ink storage cylinder, and the ink for the writing instrument is directly filled in the ink storage cylinder, and an ink backflow prevention stopper is disposed behind the ink so as to be separated from the ink. A refill for a writing instrument containing at least a colorant, an organic solvent, and a resin composition for a writing instrument comprising a resin in the ink containing cylinder, wherein the ink backflow prevention stopper is a fiber converging body that is not treated with a surfactant. A refill for a writing instrument, wherein the ink viscosity at 20 ° C. and a shear rate of 5 sec ⁻¹ is 50000 mPa · s or less.
2. The refill for a writing instrument according to item 1, wherein the fiber converging body has a thickness of 1 to 5 denier.
3. The refill for a writing instrument according to claim 1 or 2, wherein the fiber converging body is a polyester fiber.
4). The refill for a writing instrument according to any one of claims 1 to 3, wherein the organic solvent is at least an alcohol solvent or a glycol ether solvent.
5. The refill for a writing instrument according to any one of claims 1 to 4, wherein the resin contains at least a spinnability imparting resin.
6). The refill for a writing instrument according to any one of claims 1 to 5, wherein the colorant contains at least a pigment.
7). The refill for a writing instrument according to any one of claims 1 to 6, further comprising a lubricating layer on an inner surface of the ink containing cylinder.
8). A writing instrument, wherein the refill for a writing instrument comprising any one of items 1 to 7 is mounted in a shaft tube. "
And

  The present invention can provide a refill for a writing instrument that has no ink leakage due to ink backflow, has good ink followability, and good handwriting, and a writing instrument equipped with the refill.

It is the external view which partially omitted the refill for writing instruments of Example 1 was shown. FIG. 5 is an external view in which a rear end portion of an ink backflow prevention plug is inserted in a state protruding outward from a rear end of an ink storage cylinder.

As a feature of the present invention, a writing body is attached to the tip of the ink containing cylinder, the ink for the writing instrument is directly filled in the ink containing cylinder, and an ink backflow prevention stopper is separated from the ink behind the ink. A refill for a writing instrument containing at least a colorant, an organic solvent, and a resin composition for a writing instrument comprising a resin in the ink containing cylinder, wherein the ink backflow prevention plug is a fiber that is not treated with a surfactant. This is a refill for a writing instrument which is a convergent body and has an ink viscosity of 50000 mPa · s or less at 20 ° C. and a shear rate of 5 sec ⁻¹ .

  In disposing the ink backflow prevention plug of the present invention, it is necessary to dispose the fiber converging body not treated with the surfactant apart from the writing instrument ink. This is because when the ink backflow prevention plug is in contact with the ink for the writing instrument, the fiber converging body is impregnated with the ink for the writing instrument to reduce the air flow rate and prevent the air from changing. May occur or it may become impossible to write. Therefore, the specific position of the ink backflow prevention stopper is located behind the ink for writing implements and away from the ink for writing implements, and if it is at that position, its size, shape, etc. can function as an ink backflow prevention stopper. As long as the above is not impaired, there is no particular limitation.

About the ink backflow prevention stopper used by this invention, the fiber converging body formed by converging and integrating a single fiber is used. This is because by using the fiber converging body, it is easy to improve ink leakage and ink followability by maintaining a constant air flow rate and hardness.
However, simply using a fiber converging body obtained by converging and integrating single fibers is not sufficient in preventing ink leakage due to ink backflow. The inventors of the present application have made extensive studies and found that the fiber converging body is a surfactant. It has been found that it is important to use what is not processed.

  This is because, conventionally, the fiber converging body used as an ink backflow prevention plug is made by bundling single fibers and converging and integrating them, and then processing with a surfactant to make the surface of the fiber converging body easy to slip. As a result, the ink backflow prevention stopper can be easily disposed in the ink containing cylinder, and further, the generation of static electricity is suppressed and the production efficiency is easily improved. However, on the other hand, treating the fiber converging body with a surfactant has the effect of improving the wettability of the fiber converging body. When the ink flows backward, the ink easily permeates and promotes the backward flow. Therefore, it was unsuitable for use as an ink backflow prevention stopper.

  Therefore, in the present invention, it has been found that, by not treating the fiber converging body with the surfactant, it becomes difficult to get wet, so that even if the ink flows backward, it is difficult for the ink to penetrate and the ink leakage is prevented.

Further, the ink viscosity of the in-composition for writing instruments needs to be 50000 mPa · s or less at 20 ° C. and a shear rate of 5 sec ⁻¹ . This is because if the ink viscosity exceeds 50000 mPa · s, ink followability is affected, and handwriting blurring occurs and writing quality is deteriorated. Further, if the ink viscosity is less than 10,000 mPa · s, the effect of the ink backflow prevention stopper used in the present invention may be reduced, and the ink viscosity is preferably 10,000 to 50,000 mPa · s, and if considered further, the ink viscosity is 10,000 to 30,000 mPa · s. s is preferred.
In this way, by using a fiber converging body that does not treat the ink backflow prevention plug with a surfactant and having an ink viscosity at 20 ° C. and a shear rate of 5 sec ⁻¹ of 50000 mPa · s or less, it is caused by ink backflow. There is no ink leakage, ink followability is good, and the effect of improving the handwriting is obtained.

    In addition, the thickness of the single fiber of the fiber converging body is preferably in the range of 1 to 5 denier, and if it is less than 1 denier, it is difficult to secure the air flow rate, and ink followability is easily affected, and the handwriting If it exceeds 5 denier, which tends to cause scumming, it is difficult to suppress ink leakage due to ink backflow, and in view of this, 2-3 denier is preferable.

  The fiber material of the fiber converging body includes nylon fibers such as nylon 6, nylon 6, 6, etc., acrylic fibers such as polyacrylonitrile, polyester fibers such as polyethylene terephthalate fibers and copolymer polyester fibers, polyolefin fibers such as polypropylene, Examples include synthetic fibers such as vinyl fibers, semi-synthetic fibers such as rayon, and natural fibers such as wool and cotton, which are obtained by converging and integrating crimped fibers. One type of these fibers Alternatively, two or more kinds can be mixed and used.

  Among these fiber materials, it is preferable to use a polyester fiber. This is because the ink is prevented from leaking and has elasticity even if the ink flows backward, and is disposed in the ink containing cylinder. Polyester fibers are preferably used because they are easy to obtain and have a good effect on production efficiency and are not costly. Specific examples include fibers made of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), and copolymers mainly composed of these.

  Moreover, it is preferable to use the fiber converging body formed by converging and integrating the crimped single fiber as the fiber converging body not treated with the surfactant used in the present invention. By using a fiber converging body that converges and integrates crimped single fibers, this prevents ink leakage and maintains ink followability by maintaining a constant air flow rate and hardness. It is because it is possible to make it favorable. Further, the “crimping” in this case means a process for imparting crimpability to the fiber, and generally the crimp means a state in which the fiber is shrunk and bent regularly or irregularly.

  Moreover, it is preferable that the fiber convergence body which has not been treated with the surfactant is a fiber convergence body by being converged and integrated using an adhesive. This is because when the fiber converging body is used by simply compressing the fiber, the strength as the fiber converging body may be weakened. Furthermore, in this case, when arranging the fiber converging body in the ink containing cylinder, the bundled fibers may be scattered or deformed, so that the fibers are bonded to maintain the bundled state by compressing the fibers. It is preferable to perform such processing. In particular, the fiber sizing body not treated with the surfactant is preferable because the adhesive effect of the adhesive is easily obtained as compared with the fiber sizing body treated with the surfactant. This is because it tends to occur and the adhesive strength tends to be poor.

  Examples of the adhesive include polyester-based adhesives, urethane-based adhesives, phenol-based adhesives, melamine-based adhesives, etc., but when using polyester-based fibers as in the present invention, they have the same type of chemical structure. It is preferable to use a polyester-based adhesive. This is a chemical structure of the same type, so it has high adhesive strength and is easy to adhere stably for a long period of time. Even if the fiber converging body is compressed and arranged in the ink containing cylinder, the bundled fibers are scattered. This is because the shape is difficult to collapse. In particular, even when the fiber converging body swells due to the solvent in the ink, it is preferable to use it because it is easy to maintain the adhesive effect for a long time.

  In addition, when the air flow rate of the ink backflow prevention plug used in the present invention is less than 0.5 ml / min at 20 ° C. and 10 kPa under pressure in the state where it is disposed in the ink container, the air flow rate is reduced and air replacement is performed. Since it is hindered, ink followability is poor, and there is a possibility that the handwriting may be blurred or it may become impossible to write. On the other hand, when the air flow rate exceeds 300 ml / min, it is difficult to prevent ink leakage to the outside when ink backflow occurs. Accordingly, the flow rate of air passing through the ink backflow prevention plug is preferably 0.5 ml / min or more and 300 ml / min or less, more preferably 70 ml / min or more and 150 ml / min, at 20 ° C. and 10 kPa pressure. The following is more preferable.

  The air flow rate is determined by cutting the refill provided with the ink backflow prevention stopper between the ink and the ink backflow prevention stopper, and pressurizing the part where the ink backflow prevention stopper is provided from the back end side of the refill. When air was sent, the flow rate of air passing through the backflow prevention plug to the cut portion side was measured. The laminar flow tube for detecting the air flow rate was connected to the cutting portion side, and the air that passed through the ink backflow prevention plug passed through the laminar flow tube and was released into the atmosphere as it was. The air flow rate that permeates the ink backflow prevention plug is digital flow meter (manufactured by Cosmo Keiki Co., Ltd., DF-2800 (measured under pressure of 20 ° C. and 10 kPa, unit: ml / min)), 500 ml laminar flow tube ((stock) ) Measured with Cosmo Keiki LF-104-500C).

  The shape of the ink backflow prevention plug is not particularly limited, and can be formed in a substantially conical shape, a substantially spindle shape, a substantially spherical shape, or the like. In the present invention, a substantially columnar shape that can be fitted and disposed in the ink containing cylinder is particularly preferable.

  In addition, it is preferable that the ink backflow prevention stopper that does not treat the fiber converging body used in the present invention with a surfactant is compressed and disposed behind the ink for the writing instrument. This is because it is difficult to form a minute gap between the inner wall and the surface of the ink backflow prevention stopper, and it is easy to suppress ink leakage. The ink backflow prevention plug is compressed and disposed without applying excessive pressure. This is because if the air is compressed and placed under excessive pressure, the air flow rate is reduced more than necessary, and ink followability is impaired, deformed, or damaged, causing ink leakage. Because there are things. Specifically, when the volume change rate of the ink backflow prevention plug after the compression arrangement exceeds 20% with respect to the volume of the ink backflow prevention plug before the arrangement, the above-described problem due to excessive pressure occurs. If the volume change rate of the ink backflow prevention plug after the compression placement is less than 1% with respect to the volume of the ink backflow prevention plug before the placement, the ink backflow prevention plug after the placement will have an impact, etc. The volume of the ink backflow prevention plug after the compression arrangement is arranged because there is a possibility that a slight gap may be formed between the inner wall of the ink containing cylinder and the surface of the ink backflow prevention stopper. The volume change rate with respect to the volume of the previous ink backflow prevention plug is preferably 0.1 to 20%, more preferably 0.1% to 10%, most preferably 0.3%. ~ 3%.

  The writing-in-in composition used in the present invention includes both oil-based inks and water-based inks, and is composed of at least a colorant, an organic solvent, and a resin. As the organic solvent, at least an alcohol solvent or a glycol ether solvent is used. It is preferable. This is because the fiber converging body not treated with the surfactant is swollen by an alcohol solvent or glycol ether solvent, and the voids inside the fiber converging body are easily blocked, so that ink leakage due to the backflow of ink is effectively prevented. This is because it is easy to prevent, at the same time, it is easy to suppress solvent evaporation in the ink, and it is difficult for ink followability to be inferior, and when using a fiber converging body made of the polyester fiber, an aromatic alcohol solvent or It is preferable to use an aromatic glycol ether solvent. In particular, when the fiber converging body is used as a fiber converging body formed by converging and consolidating crimped single fibers, voids inside the fiber converging body are more easily blocked, thereby improving ink leakage prevention and swelling. It is preferable because it is easy to. Further, the alcohol solvent or glycol ether solvent has an effect of dissolving and stabilizing the colorant of the oil-based ink for writing instruments, and is suitably used for the oil-based ink for writing instruments.

  Further, the swelling ratio due to solvent evaporation in the ink with respect to the ink backflow prevention stopper is preferably 105% to 150%, and if the volume ratio is less than 105%, it is difficult to suppress ink leakage due to ink backflow. If the volume ratio exceeds 150%, the air flow rate is reduced and air replacement is hindered, so that the ink followability is deteriorated. Therefore, if considering further, 125% to 140% is preferable.

  Specific examples of the alcohol solvent include aromatic alcohol solvents such as benzyl alcohol, phenylethyl alcohol, methylphenyl carbinol, and phthalyl alcohol, methanol, ethanol, 1-propanol, 2-propanol, isopropanol, isobutanol, t -Aliphatic alcohols such as butanol. Specific examples of glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol monophenyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol. Examples thereof include dimethyl ether, 3-methoxybutanol, 3-methoxy-3-methylbutanol and the like, and these organic solvents can be used alone or in combination of two or more.

  Moreover, as resin used for the in composition for writing instruments, there exist an ink viscosity modifier and a spinnability imparting resin, Specifically, polyvinyl butyral resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, polyvinylpyrrolidone resin, ketone resin Terpene resin, alkyd resin, acrylic resin, styrene resin, styrene-maleic acid resin, urethane resin, polyvinyl alcohol, polyvinylpyrrolidone, and the like, and at least a spinnability imparting resin is preferably used. By adding a spinnability-imparting resin, this increases the binding property of the ink, makes it easier to pull the ink, makes it easier to improve the ink followability, and generates excess ink (crying spots) at the tip of the chip. Since it is easy to suppress, it is preferable to contain a spinnability imparting resin. Examples of the spinnability-imparting resin include polyvinylpyrrolidone and the like, specifically, trade names manufactured by IS Japan Co., Ltd .; PVP K-15, PVP K-30, PVP K-90, and PVP K-120. Etc. You may use these individually or in mixture of 2 or more types.

  Moreover, it is preferable to use at least polyvinyl butyral resin as the resin other than the spinnability imparting resin. This is because the writing instrument ink in the ink storage cylinder is in contact with the air at the rear end of the ink storage cylinder, and the polyvinyl butyral resin tends to form a thick resin film, making it difficult to move the ink. This is because there is an effect of easily suppressing the back flow of the ink. Furthermore, even if ink backflow occurs and soaks into the ink backflow prevention plug, by using the fiber converging body, covering the gaps between the fibers with the resin film of the polyvinyl butyral resin prevents ink leakage. It is preferable because it is easy to suppress. In particular, when a polyvinyl butyral resin is used, the ink is more likely to adhere to the inner wall and the remaining amount of the ink is difficult to understand.

  The content of the polyvinyl butyral resin used in the present invention is preferably 50% or more with respect to the total resin content in the oil-based ballpoint pen composition, and is preferably used as the main resin. This is because when the content of the polyvinyl butyral resin is less than 50% of the total resin content, the formation of a resin film is hindered by other resins, making it difficult to suppress ink backflow and ink leakage. . Considering further suppression of ink backflow and ink leakage, the content of polyvinyl butyral resin is preferably 70% or more with respect to the total resin content, and further considering that tendency, it is 90% or more. preferable.

Furthermore, it is preferable that the polyvinyl butyral resin has a hydroxyl group content of 25 mol% or more. Further, when a polyvinyl butyral resin having a hydroxyl group content exceeding 40 mol% is used, the amount of moisture absorption tends to increase, and the ink aging stability is likely to be affected. Therefore, a polyvinyl butyral resin having a hydroxyl group content of 40 mol% or less is preferred. Therefore, a polyvinyl butyral resin having a hydroxyl group content of 25 to 40 mol% is preferable, and a hydroxyl group amount of 30 to 40 mol% is preferable in consideration of suppressing backflow of ink and ink leakage.
The hydroxyl content (mol%) of the polyvinyl butyral resin is the content of hydroxyl groups (mol%) with respect to the total molar amount of butyral groups (mol%), acetyl groups (mol%), and hydroxyl groups (mol%). Indicates the rate.

  As for the polyvinyl butyral resin, specifically, trade names manufactured by Sekisui Chemical Co., Ltd .; ESREC BH-3 (hydroxyl group amount: 34 mol%), BH-6 (hydroxyl group amount: 30 mol%), and BX-1 (Hydroxyl group amount: 33 ± 3 mol%), BX-5 (hydroxyl group amount: 33 ± 3 mol%), BM-1 (hydroxyl group amount: 34 mol%), BM-2 (hydroxyl group amount: 31 mol%), BM -5 (hydroxyl content: 34 mol%), BL-1 (hydroxyl content: 36 mol%), BL-1H (hydroxyl content: 30 mol%), BL-2 (hydroxyl content: 36 mol%), BL-2H (Hydroxyl group amount: 29 mol%) and BL-10 (hydroxyl group amount: 28 mol%). You may use these individually or in mixture of 2 or more types.

    Moreover, it is preferable that content of a spinnability provision resin is 0.1 to 20.0% with respect to content of all the resin in the ink composition for writing instruments. This is because when the content of the spinnability imparting resin is less than 0.1% of the total resin content, there is a tendency that it is difficult to suppress the effect of improving ink followability and the occurrence of excess ink (crying blur). If it exceeds 20%, the effect of the polyvinyl butyral resin tends to be hindered. Specifically, the formation of a resin film is hindered, making it difficult to suppress ink leakage, and forming an elastic ink layer. This is because it is difficult to obtain the effect of improving writing quality. Considering the tendency to suppress excess ink, the content of the spinnability imparting resin is preferably 1.0 to 20.0% with respect to the total resin content, and the tendency to improve ink leakage and writing quality. Is considered to be 1.0 to 10.0%, and further considering the tendency, 2.0 to 7.0% is preferable.

   The colorant used in the present invention is not particularly limited to dyes, pigments, and the like, and can be appropriately selected and used. It is most preferable to contain. Examples of pigments include inorganic, organic, and processed pigments. Specifically, carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, and selenium , Triphenylmethane, perinone, perylene, goxazine, aluminum pigment, pearl pigment, fluorescent pigment, phosphorescent pigment, complementary color pigment, microcapsule pigment, and the like. Further, colored resin particles in which the pigment is covered with a transparent or translucent resin or the like, or colored resin particles or colorless resin particles colored with a pigment or a dye can also be used. These dyes and pigments may be used alone or in combination of two or more. The content is preferably 1% by mass to 20% by mass with respect to the total amount of the ink composition.

 As for the pigment, the larger the average particle diameter, the easier it is to close the voids inside the fiber converging body. Specifically, when the average particle diameter is less than 0.01 μm, it is difficult to block the voids inside the fiber convergence body, and when the average particle diameter exceeds 10 μm, the voids inside the fiber convergence body are likely to be blocked. However, since it is difficult to suppress sedimentation of the pigment and writing performance and ink stability with time deteriorate, the average particle diameter is preferably 0.01 μm to 10 μm, and the average particle diameter is 0.1 μm to 3 μm. Is most preferred.

  Moreover, about the ink storage cylinder used by this invention, it is preferable that the inner surface of this ink storage cylinder has a lubricating layer. This is because it has a lubricating layer on the inner surface of the ink containing cylinder, making the inner surface slippery, making the ink easier to slip, and improving ink followability. This is because the production efficiency is easily improved by facilitating the arrangement in the housing cylinder.

  Furthermore, when oil-based ink is used, when the ink moves inside the ink container, the ink easily adheres to the inner wall, and it is difficult to understand the remaining amount of ink. This is preferable because the relationship in which the lubricating layer is interposed in the middle is maintained without being in direct contact with the ink, and adhesion to the inner wall of the ink containing cylinder can be prevented when the ink moves. In consideration of the slipperiness, the lubricating layer used for the inner surface treatment of the ink container may be made of a surfactant such as a silicone surfactant, an acetylene glycol surfactant, a fluorine surfactant, or a dialkylsulfosuccinate. Although it is preferable to apply to the inner surface of the storage cylinder, it is preferable to use a silicone surfactant among them because it becomes easier to slip and the fiber converging body is easily disposed in the ink storage cylinder.

  Examples of silicone surfactants include dimethyl silicone, methyl phenyl silicone, methyl hydrogen silicone, alkyl aralkyl silicone, polyether silicone, and high fatty acid ester fatty acid silicone, among which slippery, excellent adhesion prevention, Alkyl aralkyl silicones are preferred because of their reactivity, considering the stability of oil-based ink components. The most effective application method is to apply uniformly to the inner wall at the time of extrusion.

  The ink storage cylinder of the refill for writing instruments used in the present invention is not particularly limited, and examples thereof include metal and resin, and the remaining amount of ink such as polypropylene and ethylene vinyl alcohol copolymer can be visually recognized. More preferably, it is made of a transparent or translucent resin. Among them, it is preferable to use polypropylene. This is because it is easy to form a lubricating film whose inner surface is more slippery by having a lubricating layer on polypropylene, so that the ink backflow prevention plug can be easily disposed in the ink containing cylinder. , Improve production efficiency.

  Next, examples of the refill for a writing instrument of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples.

Example 1
The refill 1 for a writing instrument of Example 1 shown in FIG. 1 is formed by applying a silicone-based surfactant on the inner surface of a polypropylene ink containing cylinder to form a lubricating layer. Filled with 20000 mPa · s of oil-based ink 5 (0.2 g) at a shear rate of 5 ° C. at ¹ ° C., and a ballpoint pen tip 3 holding a ball rotatably as a writing body is attached to the tip of the ink containing cylinder 2 It is. After installing the oil-based ink and ballpoint pen tip, the air in the refill for writing instruments is discharged with a centrifuge, and the polyester fiber that has not been treated with the surfactant is separated from the rear end of the oil-based ink behind the oil-based ink. A refill 1 for a writing instrument according to the present invention is obtained by disposing an ink backflow prevention stopper 6 which is a fiber converging body obtained by converging and integrating crimped single fibers made of In addition, the refill 1 for writing instruments is attached to an oil ballpoint pen (trade name: Super Grip) manufactured by Pilot Corporation, an oil ballpoint pen is produced, and the following tests and evaluations are performed using writing paper JIS P3201 as a writing test paper. went.

  Specifically, the inner diameter of the ink storage cylinder is φ1.85 mm, and the gap M from the ink rear end to the ink backflow prevention stopper is 9 mm. Further, the ink backflow prevention plug is compressed and arranged with a substantially cylindrical shape having a length L of 6.0 mm and a diameter of 1.86 mm. The air flow rate permeating through the ink backflow prevention plug at this time was 110 ml / min at 20 ° C. and 10 kPa pressure. The volume of the ink backflow prevention plug after the compression arrangement was about 1% with respect to the volume of the ink backflow prevention plug before the arrangement.

The ink composition for oil-based ballpoint pens of Example 1 has a dye as a colorant, benzyl alcohol, ethylene glycol monophenyl ether, polyvinyl butyral resin as an organic solvent, a phosphate ester surfactant as a lubricant, and a spinnability imparting resin. Polyvinylpyrrolidone and oleic acid as a stabilizer were employed, and a predetermined amount was weighed and heated to 60 ° C., and then completely dissolved using a disper stirrer to obtain an ink composition for an oil-based ballpoint pen. Specific blending amounts are as follows.
Ink viscosity of Example 1 was measured using a viscometer RVDVII + ProCP-52 spindle manufactured by Brookfield Co., Ltd. in a 20 ° C. environment at a shear rate of 5 sec ⁻¹ (rotation speed: 2.5 rpm). As a result, the ink viscosity was 20000 mPa · s.
As for the swelling property, the volume ratio after the ink backflow stopper plug was immersed in an organic solvent (phenylglycol: benzyl alcohol = 3: 2) at 20 ° C. for 1 hour was 132%. .

Example 1 (Ink formulation)
Colorant (dye) 15.0% by mass
Organic solvent (benzyl alcohol) 54.0% by mass
Organic solvent (ethylene glycol monophenyl ether) 20.5% by mass
Polyvinyl butyral resin (ESREC BH-3, hydroxyl group amount: 34 mol%) 8.0 mass%
Lubricant (phosphate ester surfactant) 1.0% by mass
Spinnability imparting resin (polyvinylpyrrolidone resin) 0.5% by mass
Stabilizer (oleic acid) 1.0% by mass

Examples 2-6
As shown in the table, Examples 2 to 6 were carried out by changing to a plurality of ink backflow prevention plugs with different air flow rates that permeate the ink backflow prevention stopper at 20 ° C. and 10 kPa, and changing the ink composition. The refills for writing instruments of Examples 2 to 6 were prepared in the same manner as in Example 1 and mounted on an oil ballpoint pen (trade name: Super Grip) to produce an oil ballpoint pen, and the following tests and evaluations were performed. The results of evaluation are as shown in Table 1.

Comparative Examples 1-5
As shown in the table, a refill for a writing instrument of Comparative Examples 1 to 5 was prepared in the same manner as in Example 1 except that the surfactant was not changed to a non-surfactant-treated ink backflow prevention plug or another type of ink backflow prevention plug. The following tests and evaluations were performed. The results of evaluation are as shown in Table 2.

Ink Backflow Test: The ink for the writing instrument was backflowed in advance until it contacted the ink backflow prevention stopper, and then left to observe for 3 days with the tip upside down.
Ink not impregnated to the back end of the ink backflow prevention stopper
Ink is impregnated to the back end of the ink backflow prevention stopper, but there is no ink leakage ... ○
Ink leakage occurred ・ ・ ・ ×

Ink following test: The handwriting after the writing test was observed with a running tester having a load of 100 gf, a writing angle of 70 °, and 4 m / min.
Very good handwriting ... ◎
Handwriting that you don't care about in practice ・ ・ ・ ○
Ink followability is poor and the handwriting is stubborn

Arrangement workability: The assembly workability when the ink backflow prevention stopper was arranged behind the writing instrument refill was evaluated.
Good assembly workability
Those with poor assembly workability

  As shown in Examples 1 to 6, none of the ink backflow prevention stoppers of the present invention produced ink leakage, and had an effect as an ink backflow prevention stopper. This is considered that ink leakage could be prevented by using an ink backflow prevention stopper that does not treat the fiber converging body with a surfactant. The ink following test showed good ink following properties and good handwriting. This is presumably because the air was smoothly exchanged and the ink followability was good because an appropriate amount of air was supplied to the trailing edge of the ink. Further, the assembling work was also good when the ink backflow prevention stopper was disposed behind the writing instrument refill.

  In Comparative Example 1, since the ink viscosity was high, the ink followability was poor, and the handwriting was severely damaged.

  As shown in the table, in Comparative Examples 2 to 4, since the polyester fiber treated with the surfactant was used as the ink backflow prevention plug, ink leakage occurred from the rear end of the refill for writing instruments.

  In Comparative Example 5, since a polymer porous body (sponge) was used as an ink backflow prevention plug, ink leakage occurred from the rear end of the refill for writing instruments.

  In this embodiment, for the sake of convenience, the ink backflow prevention stopper is disposed in the rear end inside the ink containing cylinder at a position separated from the rear end of the writing instrument ink. However, as shown in FIG. The portion may be inserted in a state protruding outward from the rear end of the ink storage cylinder. Furthermore, although not shown in the drawings, the ink backflow prevention plug is disposed on the tail plug having an air hole communicating with the inside and outside of the ink receiving cylinder. There is no particular limitation as long as it is arranged behind the writing instrument ink and spaced from the writing instrument ink. Further, in order to further suppress ink leakage due to ink backflow, a grease-like ink follower may be used in the inside of the ink storage cylinder in front of and / or behind the ink backflow prevention stopper.

  There is no ink leakage due to ink backflow, and it can be widely used as a refill for ballpoint pens that can be used for cap-type ballpoint pens, knock-type ballpoint pens, etc., even in electronic pens with built-in electronic devices etc. In particular, it can be used effectively.

1, 11 Refill for writing instruments 2 Ink storage cylinder 3 Ballpoint pen tip 4 Ball 5 Oil-based ink for writing instruments 6, 16 Ink backflow prevention plug L 5.0 mm
M 9.0mm
N φ1.85mm

Claims (7)

A writing body is attached to the tip of the ink storage cylinder, the ink storage cylinder is directly filled with the ink for the writing instrument, and an ink backflow prevention stopper is disposed behind the ink and spaced apart from the ink. A refill for a writing instrument containing at least a colorant, an organic solvent, and a resin composition for a writing instrument composed of a resin in an ink containing cylinder, wherein the ink backflow prevention plug is a fiber converging body that is not treated with a surfactant; and The ink viscosity at 20 ° C. and a shear rate of 5 sec ⁻¹ is 10,000 to 50,000 mPa · s, and the resin contains a polyvinyl butyral resin and a spinnability imparting resin, and the content of the polyvinyl butyral resin is an oil-based ballpoint pen composition. 70% or more with respect to the total resin content, and the polyvinyl butyral resin has a hydroxyl group content of 30 to 40 mol% . The content is 0.1 to 20.0% with respect to the total resin content, and the ink backflow prevention plug is compressed and arranged behind the ink composition for writing instruments, and after the compression arrangement The refill for a writing instrument is characterized in that the volume change rate of the ink backflow prevention plug with respect to the volume of the ink backflow prevention plug before installation is 0.1 to 20% . The refill for a writing instrument according to claim 1, wherein the spinnability-imparting resin is polyvinylpyrrolidone. The refill for a writing instrument according to claim 1 or 2 , wherein the thickness of the single fiber is 1 to 5 denier. The refill for a writing instrument according to any one of claims 1 to 3 , wherein the fiber converging body is a polyester fiber. The refill for a writing instrument according to any one of claims 1 to 4 , wherein the colorant contains at least a pigment. The refill for a writing instrument according to any one of claims 1 to 5 , further comprising a lubricating layer made of a silicone-based surfactant on an inner surface of the ink containing cylinder. A writing instrument comprising a refill for a writing instrument comprising any one of claims 1 to 6 mounted in a shaft tube.

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