JP3163465B2 - Water-based ink for direct liquid writing instruments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink for a writing instrument, and more particularly to a type in which a free water-based ink is stored in a shaft cylinder, and the ink is guided from the ink storage section to a pen tip via a pen core. Hereinafter, referred to as a direct liquid type).

[0002]

2. Description of the Related Art In general, a large number of thin disk bodies are arranged in parallel with a small gap (hereinafter, this gap is called a comb groove) in the pen core. running through to have ventilation grooves of large width are provided from a slit-shaped ink guide groove and the groove, the ink guiding for guiding the ink to the ink reservoir <br/> or la Paix emissions destination the axis This is the structure in which the wick is arranged, and the pen wick of this complicated structure is usually molded from a plastic material. Since the surface of the plastic material is relatively hydrophobic, the applied water-based ink contains a surfactant which imparts an affinity to the surface so as to wet the surface well.

[0003]

Generally, the addition of a surfactant to an aqueous liquid greatly reduces the surface tension of the liquid at the same time as imparting affinity to a hydrophobic surface. Ink with extremely low surface tension tends to cause ink dropping from the pen tip due to temperature changes and pressure changes inside the writing implement due to temperature changes and the attachment / detachment of the cap in the writing implement. Although the present invention exhibits a surface tension that is not extremely low, it can wet the pen core of the hydrophobic surface well, thereby making it possible for the pen core's pressure regulating action corresponding to the pressure change inside the direct liquid type writing instrument to function smoothly. It is intended to provide a water-based ink.

[0004]

The water-based ink for a direct liquid writing instrument according to the present invention has a general formula (1) as a colorant and a surfactant.
Is a polyoxyethylene polyoxypropylene alkyl ether represented in an aqueous ink comprising as essential components. As a coloring agent, eosin (CI. 45380), acid phloxine (CI. 45410), and erythrosin (CI. 45) which are usually used in aqueous inks for writing instruments are used.
430), Tartrazine (CI. 19140), Acid Violet 6B (CI. 42640), Brilliant Blue FCF (CI. 42090), Nigrosine NB (CI. 50420), and other acidic dyes, violet BB ( CI 27905), Direct Sky Blue 5B (CI. 24400), Black G (CI.
135255) and rhodamine B (C.I.
45170), Rhodamine F4G (CI. 4516)
0), Methyl Violet (C.I.42535), basic dyes such as Victoria Blue BOH (C.I.42595), fluorescent dye fees and the like are used. The colorant is used in an amount of 1 to 20% by weight, preferably 2 to 15% by weight in the ink composition.

The polyoxyethylene polyoxypropylene alkyl ether is a surfactant of a compound represented by the following general formula (1) . R—O— (C ₃ H ₆ O) _n — (C ₂ H ₄ O) _m H (1) where R is an alkyl group having 4 to 31 carbon atoms, m is a number of 1 to 30, and n is 4 To 10 respectively. The surfactant is used in an amount of 0.5 to 5% by weight in the ink composition.

Water accounts for 50% by weight or more of the ink composition. Other humectants such as ethylene glycol, diethylene glycol, propylene glycol, glycerin,
Water-soluble organic solvents such as pyrrolidone and N-vinylpyrrolidone; polyvinyl alcohol, polyvinylpyrrolidone as a fixing agent; water-soluble resins such as water-soluble salt-type polyacrylic acid and acrylic acid-styrene copolymer; preservatives; Rust agents and the like are added as needed.

[0007]

The polyoxyethylene polyoxypropylene alkyl ether generally has the above-mentioned affinity-imparting ability as compared with a polyoxyethylene derivative-based surfactant added to impart an affinity to a hydrophobic surface to an aqueous liquid. Is large,
Furthermore, unlike a polyoxyethylene-based surfactant, the addition of a small amount does not significantly lower the surface tension of the aqueous liquid. So, the aqueous ink of the present invention that the polyoxyethylene polyoxypropylene alkyl ether is added 0.5 to 5% by weight of the total amount wets well pen core made of a plastic material, the internal writing instrument due to temperature changes and the cap detachable Ink penetrates smoothly into and out of the pen-core comb groove in response to the change in air pressure, but due to the good wettability of the pen core material and the extremely low surface tension, the pen core in the capillary groove The holding function is also exhibited, and the phenomenon of ink dropping from the pen tip does not occur.

[0008]

EXAMPLES Example inks and comparative example inks having the compositions shown in Table 1 were prepared, and each of the sample inks was used as a pen body made of a resin-processed fiber bundle, and an ink guide formed of a resin-processed fiber bundle and connected to the pen body. A predetermined amount of an ABS resin pen core having a core at the center thereof is filled into a direct liquid type marking pen constituted by interposing between a pen tip and an ink storage portion of a shaft cylinder for storing free sample ink. To make a sample pen. Table 1 shows the composition and physical properties of the sample inks.

[Table 1]

The contents of the raw materials in Table 1 are described below according to the note numbers. (1) Rhodamine B (Basic basic dye, CI.
45170) (2) Rhodamine F4G (basic dye, C.I.
I. 45160) (3) Water Black R510 (acid dye, Orient Chemical Co., Ltd., CI 50420) (4) Brilliant Blue FCF (Hodogaya Chemical Co., Ltd., acid dye, CI 42090) (6) Poly Oxyethylene polyoxypropylene decyl tetradecyl ether (oxyethylene 30 mol, oxypropylene 6 mol) (7) polyoxyethylene polyoxypropylene lauryl ether (oxyethylene 12 mol, oxypropylene 8 mol) (8) polyoxyethylene polyoxy Propylene cetyl ether (oxyethylene 20 moles, oxypropylene 4 moles) (9) Polyoxyethylene lauryl ether (Daiichi Kogyo Seiyaku Co., Ltd. Neugen P) (10) Sodium dioctyl sulfosuccinate

Preparation Method of Sample Inks (1) Examples 1-4 inks and Comparative Examples 1-3 inks All components except for phenol were mixed, heated to 50-60 ° C. and dissolved by stirring. After cooling, phenol was added. And homogeneously mixed to obtain a sample ink.

The following tests were performed on the sample pens. (1) Wetability to pen core After leaving the sample pen at 0 ° C for at least 1 hour with the cap fitted, remove the cap and lower the pen tip down to an ambient temperature of 40 ° C.
The state of the ink flowing into the pen core comb groove when the ink cartridge was raised up to above and the presence or absence of ink drips from the pen tip were observed. Evaluation ○: Smooth inflow, no dripping ×: Inflow was irregular, dripping occurred (2) Ink recovery When the temperature was returned to 0 ° C after the test in the preceding paragraph, the ink storage in the pen core The state of recovery into the sample was observed. Evaluation ○: All collected well ×: Not collected, remains in pen core (3) Capability when attaching / detaching cap In / out of ink into / from pen core when cap is repeatedly attached / detached with pen tip down Was observed. Evaluation ○: Smoothly moves into the pen core at the time of detachment, and smoothly shifts to the ink storage unit at the time of fitting. The number of filled comb grooves increased, and eventually a drop from the pen tip occurred. Table 2 shows the test results.

[Table 2]

[0012]

According to the present invention as seen in the second test result table, the general
The polyoxyethylene polyoxypropylene alkyl ether represented by the formula (1) is used in the ink composition in an amount of 0.5 to 5
The water-based ink of the present invention, which contains a weight percent of the present invention, has a very low surface tension in a direct liquid writing instrument despite good wetting on the surface of the pen core made of plastic material. As a result, the ink flows smoothly into and out of the pen core comb groove, and does not cause ink dropping from the pen tip.

Claims (1)

(57) [Claims] 1. An aqueous ink for writing implements containing a dye and a surfactant, wherein the surfactant is represented by the following general formula (1).
Polyoxyethylene polyoxypropylene alkyl ethers der being is, the ink composition 0.5 to 5 wt%
Characterized by being included , through the disk in the axial direction
A slit-shaped ink guide groove and a ventilation groove wider than the groove are provided.
The ink is supplied from the ink reservoir to the pen tip at the axis.
Plastic with an ink guide wick for guiding
Ink to the pen tip through a pen core molded from
A water-based ink for direct-liquid writing instruments that is built into guiding writing instruments . R—O— (C ₃ H ₆ O) _n — (C ₂ H ₄ O) _m H (1) (where R is an alkyl group having 4 to 31 carbon atoms, and m is 1
A number from 30 to 30, and n represents a number from 4 to 10)