JPH07242094A - Drying-prevention method for writing instrument - Google Patents

Abstract

PURPOSE:To prevent happening of defective writing for a long period of time in the unused state by controlling effectively the evaporation of an ink solvent out of a writing section for the period from manufacturing a writing instrument by impregnating a writing refill with ink to the first actual writing. CONSTITUTION:One end of a writing refill 6 composed of a porous refill material is inserted into an ink storing body 7 having ink prepared by dissolving a dye into a solvent, while the other end is formed on a writing section 6a, and the writing section 6a of the writing refill 6 is coated or immersed preliminarily with a high boiling point solvent such as benzyl alcohol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing a writing tool from drying, which is used for writing with a writing core impregnated with ink.

[0002]

2. Description of the Related Art Conventionally, a writing instrument, such as a marker or a felt-tip pen, in which ink is penetrated into a writing core made of a porous core material for writing is generally used.

In the case of an oil-based ink, the above-mentioned writing instrument occludes an ink in which a dye is dissolved in an organic solvent in an ink occluding body, and one end of the writing wick is inserted into the ink occluding body, and the other end of the writing wick is inserted. The ink is made to permeate into the writing part of the so that writing can be performed.

The composition of the above oil-based ink is determined, for example, by using ethanol, normal-propyl alcohol, iso-propyl alcohol, propylene glycol monomethyl ether, benzyl alcohol, etc. as a solvent in consideration of the writing performance and the dryness of the ink after writing. A desired coloring dye is dissolved therein, and a ketone resin for fixing the dye to the writing medium is dissolved after the solvent is volatilized.

[0005]

However, when the above-mentioned writing instrument is left for a long time, there is a problem that even if it is an unused writing instrument, the writing portion is dried and a writing error occurs.

That is, in the above-described writing instrument for penetrating the ink into the writing core, the volatilization of the ink solvent from the writing part is suppressed by mounting a cap, adopting a sealing mechanism, etc.
It is designed to prevent the dry solidification of the writing part, but the solvent is volatilized by ventilating the small gap of the sealed part by leaving it for a long time, and the ink residue solidifies on the surface of the tip writing part of the writing core, It is a writing failure such as a scratched writing or a writing failure. In particular, the solvent of the oil-based ink as described above is a mixed organic solvent containing a component having high volatility, and thus writing failure will occur at an early stage.

If the cap is loose and the seal is not perfect, the unused period, that is, the time from the manufacture to the sale to the actual use by the user may not be so long. Writing defects will occur in the storage state before sales, and there is a problem that the reliability of the product is impaired.

On the other hand, when the writing instrument as described above is left in a volatile state without being written, as in the case where the tip writing section of the writing core is left open, the exposed portion of the tip of the core as described above is maintained. When the ink solvent volatilizes from the surface and the ink dries and solidifies, if the solute dye of the ink is a crystalline dye, the crystals may precipitate and grow. Specifically, depending on the volatilization conditions of the solvent or the environmental conditions to be left, the dye is deposited on the surface of the writing part of the writing core in a crystalline state as the solvent volatilizes, and the ink is sequentially supplied to the surface from the inside of the core. Then, the crystal deposited on the surface grows and the surface of the writing portion is covered with the crystal, which makes the writing impossible. Also,
When the dye in the oil-based ink is amorphous, no crystal precipitation is observed, but as described above, the tip surface of the writing core is dried and solidified along with the solvent volatilization, resulting in writing failure.

In order to suppress the volatilization of the ink from the writing portion as described above, a cap having a high airtightness is attached, and in a knock type in which the writing lead is retracted and retracted, the retractable hole is closed and closed. It is difficult to obtain a completely sealed state even if the drying prevention function such as disposing a transparent lid member is enhanced, and the components in the ink solvent may permeate depending on the type of resin that constitutes the cap. However, preventing drying for a long period of time causes an increase in cost.

In view of the above circumstances, the present invention effectively suppresses volatilization of the ink solvent from the writing part after the writing instrument is manufactured and before the first writing, thereby causing writing defects in an unused state. It is an object of the present invention to provide a method for preventing the writing instrument from drying, which is capable of preventing the writing for a long period of time.

[0011]

In order to achieve the above object, a method for preventing the writing tool from drying according to the present invention is an ink occlusion in which one end of a writing core made of a porous core material occludes an ink prepared by dissolving a dye in a solvent. Insert into the body, form the other end into the writing part,
A high boiling point solvent is applied or impregnated in advance on the writing part of the writing core.

The high-boiling solvent is preferably a solvent having a high boiling point among a plurality of solvent components in the ink, or a mixture of two or more thereof. For example, benzyl alcohol is used. is there.

Then, the high boiling point solvent is impregnated into the tip of the writing core made of a porous core material, or a writing core coated on the surface of the writing part is prepared, and the ink is assembled into a writing instrument using the writing core. In the same manner as above, with the ink penetrating or assembling a writing instrument using an untreated writing core, the high boiling point solvent is impregnated or applied to the writing part of the writing core, and the writing part The content ratio of the high boiling point solvent is increased so as to cover the surface portion of the exposed surface.

On the other hand, the dye of the ink is preferably composed mainly of an amorphous dye. Whether the dye is amorphous or crystalline can be easily determined by an X-ray diffraction spectrum or the like.

[0015]

In the method for preventing the writing tool from drying as described above, even if the ink from the ink storage material penetrates into the writing core by coating or impregnating the tip of the writing core with a high boiling point solvent, A high-boiling solvent is present at a high concentration on the surface of the writing part, and this high-boiling solvent has a slow volatilization rate and prevents the solvent of the ink penetrating inside from leaching to the writing part surface. However, by delaying the drying and solidification due to the volatilization of the ink components, it is possible to prevent the occurrence of writing defects due to the volatilization of the solvent for a long period of time. In particular, even if a completely sealed state has not been obtained, it is possible to avoid writing defects due to drying in the unused state and improve reliability, and reduce the cost by eliminating the need for a highly accurate sealed structure. Is obtained.

Further, at the start of writing, the high boiling point solvent is first derived and written. However, the writing with the oil-based ink is started after the end, and the actual writing There is no decline in the commercial value of.

On the other hand, when an ink in which an amorphous dye is dissolved is used, dye crystals are formed in the writing part as the ink solvent volatilizes even after the high-boiling solvent volatilizes or disappears by writing. No precipitation growth occurs, and writing defects are less likely to occur.

[0018]

EXAMPLES Examples of the present invention will be described below. FIG. 1 is a sectional view showing the overall configuration of a knock-type capless oil-based marker pen as a writing implement to which an embodiment of the method of the present invention is applied, and FIG. The cross section of the barrel shaft at the tip of FIG. 2 is shown in FIG.
The cutting position is rotated 90 ° with respect to the cross section.

In the knock-type writing instrument 1, an ink tank 3 is slidably fitted in a cylindrical barrel shaft 2. A pipe portion 4 is integrally connected to the tip portion of the ink tank 3, and a writing core 6 made of a porous core material such as acrylic fiber or polyester fiber is inserted into the pipe portion 4, and the tip portion thereof has a predetermined pen tip portion. It is formed in a shape and provided on the writing part 6a.

The ink tank 3 is formed in a cylindrical shape having an open rear end, and a cylindrical back plug 5 is fitted and closed at the rear end portion. The rear end portion of the back plug 5 projects from the rear end opening of the barrel shaft 2, and is movable in the barrel shaft 2 in the axial direction as a whole. A ring portion 8a of a clip 8 to be described later is rotatably interposed between the ink tank 3 and the back plug 5.

In addition, from the ink tank 3 to the inside of the back plug 5, an ink occlusion body 7 (filling pad) formed of a fibrous member in the shape of a rod is inserted, and the ink occlusion body 7 absorbs and holds the oil-based ink described later. To be done.

On the other hand, the writing core 6 fitted in the pipe portion 4 has its base end protruding from the pipe portion 4 into the ink tank 3 and in contact with the ink storage body 7 to supply the stored ink. It A writing portion 6a at the tip of the writing core 6 protruding a predetermined amount from the opening tip of the pipe portion 4 is provided so as to be able to project from the tip opening 2a of the barrel shaft 2.

The clip 8 rotatably provided on the ink tank 3 is inserted into the slit-shaped vertical groove 11 of the barrel shaft 2, and the clip 8 can be engaged with the protruding position by the shape of the vertical groove 11. Can be moved to the retracted state by pushing in the rotational direction to disengage.

Further, at the tip of the ink tank 3,
A slide ring 13 is arranged on the outer periphery of the pipe portion 4, and a cylindrical seal cap is provided inside the barrel shaft 2 in front of the slide ring 13.
14 are provided. Through hole of this seal cap 14
The pipe portion 4 and the tip writing portion 6a of the writing core 6 are slidably inserted into 14a, and the outer peripheral portion is fixed to the inner peripheral surface of the barrel shaft 2.

A lid member 15 is integrally formed on the seal cap 14 so as to be able to rise and fall, and the inner hole 14a is formed by the lid member 15.
The opening at the tip of is opened and closed. An intermediate portion of a pull thread 16 is engaged with the lid member 15, and both ends of the pull thread 16 are connected to the slide ring 13. A seal spring 17 is contracted between the slide ring 13 and the seal cap 14 to urge the ink tank 3 in the backward direction.

In the writing instrument 1 having the above structure, the ink tank 3 is retracted by the seal spring 17 and the writing portion 6a is retracted inside the seal cap 14 in the retracted state of FIG.
In this state, the slide ring 13 retracts integrally with the ink tank 3 and pulls the pull thread 16 to seal the seal cap.
The lid member 15 of 14 is closed to seal the writing portion 6a.

When the end portion of the back plug 5 is knocked into the barrel shaft 2 from the stored state, the ink tank 3 is moved forward and the pull thread 16 is loosened.
When the lid member 15 is opened, the writing portion 6a moves forward, and the tip opening portion
Writing is possible by protruding from 2a.

Next, for the oil-based ink to be occluded in the ink occluding body 7, the solvent for dissolving the dye is selected from ethanol, normal-propyl alcohol, iso-propyl alcohol, propylene glycol monomethyl ether, benzyl alcohol, etc. It is composed of a mixed solvent. The composition is determined in consideration of the writing performance and the dryness of the ink after writing. Further, a desired colored dye is dissolved in the mixed solvent, and a ketone resin for fixing the dye on the writing surface is dissolved after the solvent is volatilized. Two types of formulation examples of oil-based ink are shown below.

Formulation Example 1 Ethanol: 39.1%, Methylcellosolve: 43.9%, n-
Propanol: 6.0%, Benzyl alcohol: 3.5%,
Cyclohexane: 0.6%, Dye: 7.1% Formulation 2 Ethanol: 39.3%, Methylcellosolve: 43.9%, n-
Propanol: 6.1%, Benzyl alcohol: 3.5%,
Dye: 7.2% The writing part 6a of the writing core 6 is coated or impregnated with a high boiling point solvent in advance. As the high-boiling point solvent, one of the above-mentioned mixed solvents used for oil-based inks, which has a high boiling point, or a mixture of plural kinds thereof is used.

The boiling points of the various solvents are shown in Table 1.

[0031]

[Table 1]

The tip of the writing part 6a of the writing core 6 is impregnated beforehand with benzyl alcohol having the highest boiling point or a high-boiling solvent obtained by mixing this with propylene glycol monomethyl ether, or the surface of the writing part 6a is impregnated. It is applied to the surface of the writing portion 6a to increase the content ratio of the high boiling point solvent so as to cover the surface portion of the exposed surface of the writing portion 6a. The writing core 6 is applied or impregnated with the high-boiling point solvent in a state before the writing core 6 is incorporated into the ink tank 3 and the ink is absorbed.

After the above treatment, the oil-based ink is occluded in the ink occluding body 7, and when the ink penetrates into the writing portion 6a at the tip of the writing core 6, the oil-based ink exudes to the surface portion thereof, The high-boiling solvent (benzyl alcohol) having a high boiling point and a low volatility is present in a high concentration.

The writing core 6 is coated or impregnated with the high-boiling point solvent before the writing core 6 is incorporated into the ink tank 3 and before the writing core 6 is incorporated to absorb ink.
May be done at any time after the assembled ink has been absorbed, and the writing part 6a
It is sufficient that the high boiling point solvent is present at a high concentration so as to cover at least the surface portion of the.

Further, as the high boiling point solvent to be applied or impregnated on the writing part 6a, among the mixed solvents contained in the oil-based ink to be occluded in the ink occluding body 7 as described above,
One or more solvents with a high boiling point are mixed and used, but even if they are not contained in the ink used, a solvent with a high boiling point that has the same characteristics as the solvent in the oil-based ink is dried. It can only be used for prevention.

On the other hand, the dye of the oil-based ink with which the writing core 6 is impregnated is composed of an amorphous dye. Ink dyes used for writing instruments such as markers and felt-tip pens include crystalline dyes as well as amorphous dyes.

When the above crystalline dye is dissolved in a solvent to form an ink, when the solvent volatilizes, the dye becomes a crystalline state depending on the volatilization conditions of the solvent and the environmental conditions to be left. Precipitation occurs on the surface of the portion 6a, and the exudation of the ink from the inside to the surface is impeded to make writing impossible.
In the above point, when the amorphous dye is used, the writable state is maintained without the precipitation of crystals on the surface of the writing portion 6a even when the solvent is volatilized, but the ink dye is amorphous. The determination as to whether it is crystalline is made by an X-ray diffraction spectrum or the like.

That is, the dyes actually used have different materials for each color and often have complicated molecular structures, so it is substantially difficult to estimate the content. When a spectrum diagram is measured by, a large number of large peak points are generated in a crystalline material, so that it is easy to determine whether the material is crystalline or amorphous.

FIG. 3 shows an example of the X-ray diffraction spectrum diagram,
In the measurement of Dye Red-1 and Dye Red-2 and Dye Yellow-1 and Dye Yellow-2 shown in FIGS. 3 (A) to (D), FIGS.
Both the dye red-1 and the dye yellow-1 of No. 1 had many peaks showing a crystal structure in their spectral diagrams. On the other hand, FIG.
In the spectral diagrams of (B) and (D) Dye Red-2 and Dye Yellow-2, no peaks showing a crystal structure are found and the crystals show an amorphous state. It uses a dye.

The crystallinity can be determined by other methods than the above X-ray diffraction. Based on the above discrimination of the crystalline state,
Select and use the required dye from the amorphous dyes,
An oil-based ink of a desired color is formed and stored in the ink storage body 7.

Next, with respect to the method for preventing drying of the writing instrument of the present invention as in the above example, the result of measuring the effect of preventing drying, that is, the writability after standing (dry and solidified state) is shown in FIG. The comparative example is a writing instrument having the same structure and the same oil-based ink, which is not treated with the high boiling point solvent impregnated in the writing part 6a.

The measurement was carried out by exposing the writing part 6a of the writing core 6 in the air and leaving the writing part 6a in an open state, and determining the writing performance, that is, the time when a blur occurs or writing becomes impossible. . The dye of the oil-based ink used was Ink No. 6 described later, which was the amorphous dye red-2 and the amorphous dye yellow-.
The test is performed with a writing instrument using an oil-based ink prepared by mixing 2. The environmental conditions are room temperature and relative humidity of 25% RH.

In the case of the untreated one, the writing part was dried and solidified in a short time due to the evaporation of the solvent of the oil-based ink, the writing was faint within 1 hour, and the writing was impossible in about 6 hours.
On the other hand, in the case where the writing part 6a is impregnated with a high-boiling solvent (benzyl alcohol), the state where it can be written without the occurrence of dry solidification even after leaving it open for 24 hours is maintained, and it is faint. Good writing performance was obtained by preventing the occurrence of the unwritable state. Moreover, almost the same result was obtained even if the relative humidity of the environmental conditions was raised to 80% RH.

Further, an oil-based ink is prepared by using the crystalline dye and the amorphous dye, and the oil-based ink is occluded in the oil-based marker pen having the structure of the above-mentioned embodiment, and the writing part is exposed to be exposed to environmental conditions. If changed and left to stand in the air, the state of crystal precipitation or dry solidification changes depending on each condition. The test results are shown in FIGS. In the tests of FIGS. 5 to 7, the above-mentioned drying prevention treatment with a high boiling point solvent was not performed.

Temperature conditions are changed to room temperature and 50 ° C., humidity conditions are changed to normal humidity and saturated humidity at room temperature, and relative humidity is changed to 50 ° C.
It is changed to 25% RH and 80% RH. Generally, surface solidification and crystal precipitation tend to occur at higher temperatures, and higher humidity tends to cause crystal precipitation and growth. Is to have.

Inks No. 1 and No. 3 in FIGS. 5 and 6 are results obtained by using the inks prepared by using the crystalline dyes Red-1 and Yellow-1. With a writing instrument, crystal precipitation and growth of the dye can be seen. Particularly, in Red-1, crystals were precipitated and grown in an extremely short period under the condition of 50 ° C and 80% RH, and in Yellow-1, crystals were precipitated and grown in a short period at room temperature and saturated humidity.

In contrast, the inks No. 2 and No. 4 are the results obtained by the inks prepared by using the amorphous dyes Red-2 and Yellow-2, and the writing portion of the writing core is opened. Even if left in the state, crystal precipitation is not observed, only surface solidification occurs.

Further, the ink No. 5 in FIG. 7 is the result of the oil-based ink in which the amorphous dye red-2 and the crystalline dye yellow-1 are mixed, and in this case, the ink No. 3 is used.
As in the case of yellow-1 alone, crystal precipitation occurs and grows at room temperature and saturated humidity in a short period of time. Ink No. 6
Is the case of an oil-based ink obtained by mixing amorphous dye Red-2 and amorphous dye Yellow-2, and in this case, crystal precipitation did not occur.

From the above results, corresponding to the measurement of the X-ray diffraction spectrum, when a crystalline dye is added to the dye, crystal precipitation occurs, and an oil-based ink is prepared mainly with an amorphous dye. Thus, even after the high boiling point solvent has disappeared by writing, it is possible to prevent the crystal from precipitating and growing in the writing portion 6a. In the case where a small amount of crystalline dye is added to the amorphous dye, the amount of crystal precipitation may be small and may not be a practical problem.

Although only the knock-type writing implement is shown in the above-mentioned embodiment, a high-boiling solvent is similarly applied to the writing part in the writing implement of the type in which the sealing cap is attached and detached so as to cover the tip writing part of the writing core. It may be applied or impregnated.

[0051]

According to the method for preventing drying of the writing instrument of the present invention as described above, a high boiling point solvent is used in the writing portion of the writing core inserted into the ink storage body storing the ink having one end dissolved in the solvent. By applying or impregnating in advance,
The high boiling point solvent, which has a low volatilization rate, is present at a high concentration on the surface of the writing part, which prevents evaporation of the ink solvent penetrating inside from the surface of the writing part and delays drying. Can be prevented for a long period of time and reliability can be improved.

Further, when an ink containing an amorphous dye is used, even after the high boiling point solvent volatilizes or disappears from the writing part by writing, dye crystals do not precipitate and grow in the writing part. Furthermore, it is possible to prevent the occurrence of writing defects.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall configuration of a writing instrument to which an embodiment of the method of the present invention is applied.

FIG. 2 is a cross-sectional view of the main part of the tip of the writing instrument that is ready for writing.

FIG. 3 X-ray diffraction spectrum of various dyes

FIG. 4 is a diagram showing a measurement result of an anti-drying effect.

5 to 7 are diagrams showing results of a drying test of inks using various dyes.

[Explanation of symbols]

 1 Writing tool 2 Barrel shaft 3 Ink tank 6 Writing core 6a Writing part 7 Ink storage material

Claims (4)

[Claims] 1. A writing instrument in which one end of a writing core made of a porous core material is inserted into an ink occlusion body that has occluded ink formed by dissolving a dye in a solvent, and the other end is formed in the writing part. A method for preventing drying of a writing instrument, which comprises applying or impregnating a high-boiling-point solvent on the writing part of the lead in advance. 2. The method for preventing dryness of a writing instrument according to claim 1, wherein the high boiling point solvent is a solvent having a high boiling point among solvents of a plurality of components in the ink. 3. The method for preventing drying of a writing instrument according to claim 1, wherein the high boiling point solvent is benzyl alcohol. 4. The method for preventing dryness of a writing instrument according to claim 1, wherein the dye of the ink contains an amorphous dye as a main component.