JPH08157765A - Oil-base ink composition for ball-point - Google Patents

Abstract

PURPOSE: To provide an oil-base ink compsn. for a ball-point which not only provides a smooth touch in writing inherent in a low-viscosity ink but also does not cause bleeding nor undesirable outflow. CONSTITUTION: The compsn. at least contains a colorant, an org. solvent, and a stringiness-imparting polymer and has a viscosity of 2,000-10,000mPa.s at 20 deg.C and a length of the ink strings of 100mm or higher at 20 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink composition for oil-based ballpoint pens, and more specifically, it has a lower writing viscosity than conventional inks for oil-based ballpoint pens, and has a smooth writing feel and performance without tearing or tearing. The present invention also relates to an ink composition for an oil-based ballpoint pen that also has the above-mentioned properties.

[0002]

2. Description of the Related Art Conventionally, inks for oil-based ballpoint pens are usually
Viscosity at 20 ° C is about 10,000-30,000 mPa
It has a high viscosity of about s. The reason is that it has a well-balanced viscosity range from the viewpoint of various performances as a ballpoint pen that is easy to write, has no bleeding (strike through), tears, spills, and ink leakage.

On the other hand, the viscosity is 10,000 mPa · s (2
Various inks for low-viscosity oil-based ballpoint pens that have been lowered to 0 ° C.) or lower have been proposed. For example, JP-A-63-309571 proposes an ink whose viscosity at 25 ° C. is adjusted to be in the range of 3,000 cPs to 5,000 cPs. Further, JP-A 1-299880 proposes an oil-based ink for a ballpoint pen, which is composed of at least a colorant, an organic solvent and a viscosity modifier, and has an ink viscosity of 50 to 2,000 cPs (25 ° C.). .

[0004]

However, the high-viscosity oil-based ballpoint pen ink has a drawback in that a smooth writing feel cannot be obtained, and the low-viscosity oil-based ballpoint pen ink can obtain a smooth writing feel. There is a problem that burrs are likely to occur.

An object of the present invention is to provide an ink composition for oil-based ballpoint pens, which has both a smooth writing quality of a low-viscosity ink and a performance without crying or blurring.

[0006]

In order to achieve the above object, the invention according to claim 1 of the present invention comprises at least a colorant, an organic solvent and a spinnability imparting polymer and is at 20 ° C.
The viscosity is 2,000 to 10,000 mPa · s, and the tow thread length at 20 ° C. is 100 mm or more.

The invention according to claim 2 of the present invention is
The spinnability imparting polymer is a polyvinylpyrrolidone resin having a weight average molecular weight of 1,000,000 or more.

The invention according to claim 3 of the present invention is
The spinnability imparting polymer is a polyvinylpyrrolidone resin having a weight average molecular weight of 2,000,000 or more.

The invention according to claim 4 of the present invention is
It is characterized by containing 5 to 50% by weight of a colorant, 0 to 40% by weight of a viscosity modifier, 30 to 90% by weight of an organic solvent, and 0.1 to 5% by weight of a spinnability imparting polymer.

As a result of studies to achieve the above object, the present inventors have found that the viscosity is 2,000 to 10,000 mPa · s.
It has been found that an oil-based ink for a ballpoint pen, which is in the range of (20 ° C) and has a tow thread length of 100 mm or more (20 ° C), is preferable. That is, the viscosity is 2,000 to 10,
It is in the range of 000 mPa · s (20 ° C.), and the yarn length imparting polymer at 20 ° C. is 100 m by adding the spinnability imparting polymer.
It was found that by making an oil-based ink of m or more and filling this ink in a ball-point pen, a smooth writing feeling can be obtained and crying and blurring can be largely prevented.

As described above, the viscosity is 10,000 mPa ·
With a low-viscosity ink lowered to s (20 ° C.) or lower, a smooth writing taste can be obtained, but tearing and burning occur. The present inventors believe that viscoelasticity of ink is important for preventing crying and swelling,
In particular, it was found that there is a strong correlation with the spinnability, and as a result of further research, a spinnability imparting polymer having a spinnability of 100 mm was used.
It was clarified that good results were obtained with the oil-based ink prepared above. If the length of this string is less than 100 mm, the elastic component of the viscoelastic element of the ink is insufficient,
Insufficient force to return excess ink from the tip of the pen to the inside of the tip is insufficient, which appears as tears and squirts when writing.

Such a tendency is most serious when an ink having a reduced ink viscosity is used without adding a spinnability imparting polymer, since the viscous element becomes stronger, and the spinnability imparting polymer is added to the spinnability. However, if the ink viscosity is less than 2,000 mPa · s (20 ° C), weeping or spilling will be ineffective and ink leakage from the pen tip will occur easily Easier to do. But,
Viscosity is 2,000 mPa · s (20 ° C) or higher, and
When an oil-based ink with a thread length of 100 mm or more is used, the elastic element is strengthened even with low-viscosity ink, and it is possible to achieve both the smooth writing quality that is characteristic of low-viscosity ink and the beautiful handwriting without crying or blurring. It will be possible. Therefore, the viscosity of the oil-based ballpoint pen ink of the present invention is in the range of 2,000 to 10,000 mPa · s at 20 ° C.,
The tow length must be greater than 100 mm at 20 ° C.

Ink viscosity is 3,000 to 10,000 m
If it is Pa · s (20 ° C.), the desired string length can be easily obtained by adding the string-imparting polymer. Further, if the length of the towing thread is 200 mm or more, the elastic element of the ink becomes stronger and the force of pulling the excess ink back into the tip, that is, the so-called ink return effect is fully exerted, so that the prevention of crying and drooling is greatly achieved. Be improved.

In the present invention, the tow length is measured as follows. At 20 ° C room temperature, use a measurement environment that is not affected by wind, and add about 10 inks to a 20 ml glass beaker.
g Weigh. Next, the glass rod having a diameter of 5 mm is set so that the tip thereof is immersed in the ink for 5 mm. Subsequently, when the glass rod was pulled up at a constant rate in the vertical direction at a pulling rate of 31 mm / sec, the length of the ink at the time when the towing thread was broken was measured, and this was taken as the towing thread length.

As the colorant, any dye or pigment conventionally used in ink compositions for oil-based ballpoint pens can be used without particular limitation. Specifically, as the dye, an alcohol-soluble dye, an oil-soluble dye, a direct dye, an acid dye, a basic dye, a metal-containing dye, and various salt-forming dyes can be used. Further, as the pigment, both organic and inorganic pigments can be used. These may be used alone or as a mixture, and are preferably 5 to 50% by weight with respect to the total amount of the ink composition.

The organic solvent is used for the purpose of dissolving or dispersing a colorant, a solvent for a resin, or preventing the ink from drying with a pen tip, and the organic solvent used in conventional ink compositions for oil-based ballpoint pens can be used. Specifically, benzyl alcohol,
Alcohol-based and glycol-based such as propylene glycol and butylene glycol, cellosolve-based such as phenyl cellosolve, carbitol-based such as phenylcarbitol, and nitrogen-containing solvent-based such as N-methylpyrrolidone can be used alone or as a mixture. Is 30 to 90% by weight based on the total amount of the ink composition.

In the present invention, examples of the spinnable polymer used for imparting spinnability to the ink include polymers having a molecular weight of 100,000 or more. Polyvinylpyrrolidone, polyethylene oxide, hydroxypropyl cellulose,
A rubber-based polymer compound or the like can be used. Among these, a polyvinylpyrrolidone resin having a weight average molecular weight of 1,000,000 or more is preferable. Most preferably the weight average molecular weight is 2
It is desirable to use a polyvinylpyrrolidone resin of at least 1,000,000. Specifically, PVP K-90 (manufactured by GAF, weight average molecular weight 1.28 million) and PVP K-120 (manufactured by GAF, weight average molecular weight 2.8 million) are 0.1% by weight or more based on the total amount of the ink. The addition can give a string length of 100 mm or more. The spinnability imparting polymer can be added up to 5% by weight.

In the present invention, the desired ink can be obtained by blending a colorant, an organic solvent and a spinnability imparting polymer, but it is preferable to add a viscosity modifier in order to obtain a desired ink viscosity. . The viscosity modifier is a ketone resin,
Examples thereof include phenol resins, amide resins, xylene resins, hydrogenated rosin resins, rosin resins, and polyvinylpyrrolidone resins having a weight average molecular weight of less than 1,000,000. These can be used alone or as a mixture, and are preferably 0 to 40% by weight based on the total amount of the ink composition.

In addition to the above components, the oil-based ballpoint pen ink composition of the present invention may optionally contain a surfactant, a dispersant, and
A rust preventive agent, an antibacterial agent, a lubricant, a pH adjuster, a dye dissolution stabilizer, a solubilizer, etc. may be appropriately selected and added.

[0020]

EXAMPLES Examples and comparative examples of the present invention will be shown below.

Example 1 Nigrosine EX 35.0% by weight (manufactured by Orient Chemical Industry Co., Ltd.) Benzyl alcohol 23.8% by weight Phenylcellosolve 35.0% by weight Oleic acid 5.0% by weight PVP K-90 1.2 % By Weight After mixing the above components, the mixture was heated and stirred at 60 ° C. to dissolve the dye and resin to obtain a black oil-based ballpoint pen ink having a viscosity of 4,000 mPa · s (20 ° C.). The towing length of this ink was 106 mm.

Example 2 Nigrosine EX 15.0% by weight Varifast Violet 1701 20.0% by weight (Orient Chemical Co., Ltd.) Hirac 111 5.0% by weight (ketone resin, Hitachi Chemical Co., Ltd.) Benzyl alcohol 21.4% by weight Phenyl cellosolve 33.0% by weight Oleic acid 5.0% by weight PVP K-90 0.6% by weight After mixing the above components, a viscosity of 6,000 was obtained in the same manner as in Example 1.
A black oil-based ink for a ballpoint pen of 0 mPa · s (20 ° C.) was obtained. The tow thread length of this ink was 120 mm.

Example 3 Nigrosine EX 15.0% by weight Varifast Violet 1701 20.0% by weight Hirac 111 4.0% by weight Benzyl alcohol 22.4% by weight Phenylcellosolve 33.0% by weight Oleic acid 5.0% by weight % PVP K-120 0.6 wt% After mixing the above ingredients, a viscosity of 7,000 was obtained in the same manner as in Example 1.
A black oil-based ink for a ballpoint pen of 0 mPa · s (20 ° C.) was obtained. The tow thread length of this ink was 290 mm.

Example 4 Spyron Blue BPNH 20.0 wt% (Hodogaya Chemical Co., Ltd.) Spyron Violet C-RH 5.0 wt% (Hodogaya Chemical Co., Ltd.) Hirac 111 19.0 wt. % Benzyl alcohol 11.0% by weight Phenylcellosolve 44.4% by weight PVP K-120 0.6% by weight After mixing the above components, a viscosity of 7,000 was obtained in the same manner as in Example 1.
A blue oil-based ink for a ballpoint pen of 0 mPa · s (20 ° C.) was obtained. The pulling length of this ink was 300 mm or more.

Example 5 SPT Orange 6 5.0 wt% (Hodogaya Chemical Co., Ltd.) Varifast Red 1320 20.0 wt% (Orient Chemical Co., Ltd.) Hirac 111 21.0 wt% Benzyl Alcohol 10.4% by weight Phenylcellosolve 43.0% by weight PVP K-90 0.6% by weight After mixing the above components, a viscosity of 8,000 was obtained in the same manner as in Example 1.
A red oil-based ink for a ballpoint pen of 0 mPa · s (20 ° C.) was obtained. The tow thread length of this ink was 160 mm.

Comparative Example 1 Nigrosine EX 35.0% by weight Phenylcellosolve 60.0% by weight Oleic acid 5.0% by weight After mixing the above components, the same procedure as in Example 1 was followed to obtain a viscosity of 3,000.
A black oil-based ink for a ballpoint pen of 0 mPa · s (20 ° C.) was obtained. The towing length of this ink was 30 mm.

Comparative Example 2 Nigrosine EX 30.0% by weight Hirac 111 12.0% by weight Phenylcellosolve 58.0% by weight After the above components were mixed, the viscosity was 22.0 as in Example 1.
A black oil-based ballpoint pen ink of 00 mPa · s (20 ° C.) was obtained. The pulling length of this ink was 95 mm or more.

Comparative Example 3 SPT Orange 6 5.0 wt% Varifast Red 1320 20.0 wt% Phenyl Cellosolve 73.0 wt% PVP K-90 2.0 wt% After mixing the above ingredients, the same as Example 1 And viscosity 1,90
A red oil-based ink for a ballpoint pen of 0 mPa · s (20 ° C.) was obtained. The tow thread length of this ink was 50 mm.

Each of the inks of Examples 1 to 4 and Comparative Examples 1 to 3 was used with a ballpoint pen (trade name "BP-S", manufactured by Pilot Co., Ltd., a stainless steel ballpoint pen tip having a 0.7 mm diameter ball. ) And tested. The results are shown in the table.

[0030]

[Table 1]

Writing taste: The smoothness of the writing feeling was judged by a handwriting sensory test. ◎: Very smooth writing quality ○: Smooth writing quality △: Slightly heavy writing quality ×: Heavy writing quality Crying: In the running test, the ink collected at the tip of the ballpoint pen tip after running 100 m is spread on a paper, spread with a spatula, and cried. Was measured. ⊚: Very small or less ○: Small Δ: Medium ×: Larger or more Vent: Four running in the running test, the number of bosses per 100 m was measured, and the average value of the four was taken. ◎: No spill ○: 1 or less △: 1 or more 5 ×: 5 or more

[0032]

As is clear from the above results, the viscosity at 20 ° C. is 2,000 to 10,000 mPa · s, 20
The ink composition for oil-based ballpoint pens of the present invention having a tow length of 100 mm or more at 0 ° C. exhibited excellent performance in all test items and was extremely useful.

Claims (4)

[Claims] 1. A composition comprising at least a colorant, an organic solvent, and a spinnability imparting polymer, and has a viscosity at 20 ° C. of 2,000.
An oil-based ink composition for a ballpoint pen, which has a length of 0 to 10,000 mPa · s and a towing thread length at 20 ° C. of 100 mm or more. 2. The ink composition for an oil-based ballpoint pen according to claim 1, wherein the spinnability imparting polymer is a polyvinylpyrrolidone resin having a weight average molecular weight of 1,000,000 or more. 3. The ink composition for an oil-based ballpoint pen according to claim 1, wherein the spinnability imparting polymer is a polyvinylpyrrolidone resin having a weight average molecular weight of 2,000,000 or more. 4. Coloring agent 5 to 50% by weight, viscosity adjusting agent 0 to
The ink composition for an oil-based ballpoint pen according to any one of claims 1 to 3, which contains 40% by weight, an organic solvent of 30 to 90% by weight, and a spinnability imparting polymer addition amount of 0.1 to 5% by weight.