JPS61200187A - Back-flow prevention aqueous ink composition for ball point pen - Google Patents

Abstract

PURPOSE:To the titled composition effecting prevention of adherence of the same on the inner surface of the ink cartridge as much as possible, by incorporating hard-volatile organic liquid as ester. CONSTITUTION:The objective composition as an aqueous ink with a viscosity 50-200CPS at 25 deg.C in cartridge, can be obtained by incorporating (A) as base agent, a hard-volatile or non-volatile organic liquid selected from hydrocarbons (e.g., liquid paraffin) with (B) a gelling agent (e.g., particulate silica) and (C) a pentaerythritol fatty acid ester (e.g., pentaerythritol laurate).

Description

Detailed Description of the Invention (Industrial Application Field) The present invention has a viscosity of 50 to 2000 CPS (at 25°C).
Regarding the improvement of the ink backflow preventer composition provided above the ink in the ink storage tube in a ballpoint pen using water-based ink, particularly an ink backflow preventer composition for a water-based ballpoint pen that prevents adhesion to the inner surface of the ink storage tube as much as possible. relating to things.

(Prior art and its problems) The oil-based ink traditionally used in oil-based ink ballpoint pens has a very high viscosity, ranging from several thousand to 10,000 CPS. If the inner diameter of the storage tube is 2.8 (mm) or less, it is not necessarily necessary to provide the ink backflow prevention composition.
When the inner diameter is 2.8 (rrrn) or more, the pen reliably advances toward the pen tip as ink is consumed by writing.

In addition, when the writing instrument is subjected to impact or placed in a high temperature environment, there is a sufficient concern that ink may leak from the rear end of the ink storage tube, so Vaseline, silicone grease, etc. that can prevent this It is known that it is necessary to provide an ink backflow preventer composition, such as silicone oil, a mixture of liquid paraffin and petrolatum, in the ink storage tube above the ink.

Due to the high viscosity of the ink in an oil-based ballpoint pen equipped with such an ink backflow prevention composition, when writing, the ink is drawn out to the pen tip in just the right amount by using atmospheric pressure or its own weight. The original purpose of the ink backflow preventive composition is to be able to follow the ink without adhering to the inner surface of the ink storage tube as the ink is consumed, thereby preventing ink from leaking from the rear end of the ink storage tube. However, it is possible to achieve this.

If such an ink backflow preventer composition is used as it is in a ballpoint pen using a water-based ink with a viscosity of about 50 to 200 OCP S, which is lower in viscosity than oil-based inks, the following problems will occur.

In other words, the amount of ink ejected from the nib of a ballpoint pen using low-viscosity water-based ink is approximately 0.2 (g/200 m), compared to approximately 0.03 (g/200 m) for general oil-based ink.
(g/200 m2), and the speed at which the ink backflow prevention composition in a water-discharging ballpoint pen follows the ink naturally becomes high. Therefore, this ink backflow preventer composition is required to promptly respond to ink consumption and reliably follow it, but in reality, this ink backflow preventer composition does not respond to the ink consumption rate. It becomes impossible to follow,
As a result, the ink tends to adhere to the inner surface of the ink storage tube relatively easily compared to oil-based ink, which not only causes ink discharge failure due to reduced pressure within the ink storage tube, but also causes gradual defects in the ink backflow preventer composition, resulting in a decrease in the amount of ink. do.

The problem is that even the object itself disappears, and it no longer serves its original purpose.

(Means for Solving the Problem) In view of the above-mentioned circumstances, the present inventors have determined that the viscosity is 50 to 200.
In order to prevent the ink backflow preventive composition from adhering to the inner surface of the ink storage tube in ballpoint pens using 0 CPS water-based ink, we have conducted intensive research on various additives, and as a result we have developed a non-volatile additive selected from hydrocarbons. It was discovered that the most suitable product is one that is based on a volatile organic liquid or a non-volatile organic liquid, to which a gelling agent and a pentaerythritol fatty acid ester are added.

This invention has finally been completed.

That is, the present invention provides an ink backflow preventive composition for a water-based ballpoint pen, the ink storage tube being filled with a water-based ink having a viscosity of 50 to 2000 CPS at 25°C, the ink backflow preventive composition containing hydrocarbons. For use in water-based ballpoint pens, the ballpoint pen is made of a non-volatile organic liquid or a non-volatile organic liquid selected from the above, and a gelling agent and one or more pentaerythritol fatty acid esters are added thereto. The gist is an ink backflow preventer composition.

Examples of the non-volatile organic liquid or non-volatile organic liquid selected from the hydrocarbon base used in the present invention include polybutene LV-100, polybutene HV-15. Same HV-3
5 (the above 2 manufactured by Nippon Oil Corporation), liquid halafine, α-olefin oligomer, spindle oil, vaseline, etc.

These can be used alone or in combination of two or more.

Also, as a gelling agent used in the present invention.

Fine particle silica such as Aerosil (manufactured by Nippon Aerosil ■), hydrogenated castor oil-based products such as Disbaron 305 (manufactured by Kusumoto Kasei ■), cellulose-based products such as Soloid and Rheovar K E (manufactured by Sansho ■), Further examples include metal soaps and bentonite. As a gelling agent 1, for example, it has a silanol group on the surface and its secondary particle size is several mμ.
If fine particle silica having a particle size of 50 mμ is used, the ink backflow preventive composition will have a transparent feel, and if the ink storage tube itself is transparent, a good-looking product can be obtained.

The blending ratio of these gelling agents is preferably 1 to 20% by weight. If it is less than 1% by weight, the gelling strength of the ink backflow preventive composition will be weak and the ink will easily flow back, and if it is more than 20% by weight, the gelling strength will be too strong and it will not follow the ink. It tends to get worse.

Next, pentaerythritol fatty acid ester, which is also a feature of the present invention, will be described.

As mentioned above, the pentaerythritol fatty acid ester as an additive is added to prevent the ink backflow preventer composition from adhering to the inner surface of the ink storage tube. , pentaerythritol stearate, pentaerythritol oleate, pentaerythritol palmitate, etc., and these can be used alone or in combination.

2. The water-based ink to which the ink backflow preventive composition of the present invention is used has a viscosity of 50 to 2 at 25°C.
000CPS is preferred. This is because the inventors of the present invention have found that the advantage of conventional oil-based ballpoint pens is that they are structurally simple, and the advantage of conventional water-based ballpoint pens that use an extremely low viscosity ink of several CPS, which is the fresh, clear handwriting. This comes from the knowledge that we came to after conducting various studies in order to create a ballpoint pen that has both of these features.

(Example) The present invention will be explained in more detail with reference to two examples below. In the examples, "part" indicates "part by weight 1."

Example 1 Poly 1 Ten HV-15 (manufactured by Nippon Oil Corporation) 94.6 parts Aerosil R972 (gelling agent 2 manufactured by Nippon Aerosil Corporation) 5.
A blend containing 0.4 parts or more of pentaerythritol stearate was placed in a kneader and heated and stirred for 2 to 3 hours to obtain an ink backflow preventer composition for a water-based ballpoint pen.

Example 2 Boridetene LV-100 (manufactured by Nippon Oil Company) 9
3 parts Aerosil Rq72 (gelling agent.

(manufactured by Nippon Aerosil ■) 6.0 parts Pentaerythritol oleate 1 part or more was mixed in the same manner as in Example 1 to obtain an ink backflow preventer composition for an aqueous ballpoint pen.

Comparative Example A comparative example was prepared in the same manner as in Example 1 except that the pentaeryth IJ)-lestearate in Example 1 was removed.

(Effect of the invention) Above are Examples 1.2. Each of the ink backflow preventer compositions obtained in the comparative examples had a viscosity of 250 ml containing the following composition.
Filled with CPS water-based ink.

Ink was filled into the upper part of an ink storage tube (material: polypropylene, inner diameter: 3.2 mm) with a nickel silver ballpoint pen tip attached to one end, writing load was 100 g, and writing angle was 7.
Bright line writing was performed under the conditions of 0° and a writing speed of 7 cm/See.

The results are shown in the table below.

(Composition of water-based ink) Water Black 187L (manufactured by Orient Chemical Industry Co., Ltd.) aO part Polyvinylpyrrolidone, 19010 parts ethylene glycol 15 parts Sasunix PP-400 (lubricant, Sanyo Chemical Co., Ltd.) 10 parts water
57
As is clear from the above description, according to the ink backflow preventer composition for water-based ballpoint pens of the present invention, when a water-based ink with a viscosity of 50 to 2000 CPS is used, the viscosity decreases as the ink consumption decreases. The ink reliably follows the ink without adhering to the inner surface of the ink storage tube, and does not cause ink discharge failure (and the ink backflow preventer composition does not disappear during the process).

It has excellent effects.

Claims (1)

[Claims] The viscosity at 25℃ in the ink storage tube is 50 to 2000.
An ink backflow preventer composition for a water-based ballpoint pen filled with a water-based ink that is CPS, wherein the ink backflow preventer composition is based on a non-volatile organic liquid or a non-volatile organic liquid selected from hydrocarbons. An ink backflow preventive composition for an aqueous ballpoint pen, characterized in that a gelling agent and one or more pentaerythritol fatty acid esters are added thereto.