JPS602946Y2 - water-based ink ballpoint pen - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a water-based ink ballpoint pen that uses water-based ink whose main component is water.

Water-based ink ballpoint pens using water-based ink have recently become popular in place of ballpoint pens or felt-tip pens that use oil-based ink.

These water-based ink ballpoint pens have the disadvantages that oil-based ink ballpoint pens had: dirt on the writing edge, resulting dirt on fingers and writing surface, inability to write due to loss of fluidity of ink in winter, and hard writing feel. etc. were solved.

The water-based ballpoint pen ink currently on the market has a viscosity of 2 to 4 CpS (at 20°C) and a surface tension of 40 dyn.
Ballpoint pens are made by impregnating ink into a cylinder containing an ink absorbing body made of fiber bundles, such as those used in felt-tip pens, or by filling a spare ink cylinder, such as those used in cartridge 2 fountain pens, with ink. Connected to guide ink to the tip.

In water-based ballpoint pens using this low viscosity ink,
When the ball rotates during writing, it is difficult for ink to adhere to the ball, and the amount of ink flowing out may be insufficient, resulting in thin writing lines.In particular, when writing at high speed, ink is likely to fade or blur.

Therefore, the higher the viscosity of the ink, the better the ink will adhere to the ball, but the flow of the ink on its way from the ink cylinder to the ball will become worse.

Furthermore, when an ink with extremely high viscosity is used, there is a slight disadvantage that the writing end becomes smudged, unlike a ballpoint pen using oil-based ink.

As a result of the inventor's research, it was found that setting the ink for water-based ballpoint pens to have a medium viscosity, that is, 10 to 70 cps (at 20 degrees Celsius) and a surface tension of 30 to 60 dyne/cm (at 20 degrees Celsius), is the best way to ink the ball. It was confirmed that the adhesion of the ink was good, and that if special settings were made to the internal structure of the ballpoint pen, the ink could flow smoothly from the ink cylinder to the ball.

The structure will be described in Examples below.

In the figure, 1 is a ballpoint pen tip made of metal or thermosetting resin such as polyacetal.
A ball fitting hole 2a for accommodating the ball 2 is bored at the tip,
Subsequently, a small diameter ink suction groove 2b and a large diameter center hole 2c are concentrically bored.

An ink guide body made of a resin-processed synthetic fiber bundle is inserted into the center hole 2c.

An ink tube 4 is connected to the inner end of the chip, and is filled with ink 5 and an ink backflow prevention agent 6 in contact with the ink.

Reference numeral 7 denotes a shaft cylinder connected to the tip 1 and fitted onto the ink tube 4.

In this invention, it is important to specify the more specific structure of the ink extractor 3 having the above structure, the physical properties of the ink 5, and the ink backflow prevention agent 6.

The ink deriving body 3 is made of polyacrylonitrile synthetic fiber, polyamide synthetic fiber, or polyester synthetic fiber with a diameter of 2 to 7 deniers and a thermosetting resin such as phenol resin, melamine resin, polyester resin, or epoxy resin. The rod is hardened to a porosity of 30 to 50% and its length is 1.0 to 3. Oo1 volume is 0.02~0
．． 1c11 is suitable.

If the diameter of the single fiber becomes large, the fibers are crimped more, or the amount of resin for curing is less, the voids become pores and the ink holding power becomes weaker.

Further, even if the porosity is large, the ink retention force becomes weak.

If the ink holding power is weak, ink may easily blow out or leak due to impact or temperature changes.

Conversely, if the diameter of the fibers becomes smaller, the crimp of the single fibers decreases, or the amount of resin for curing increases, the voids become denser and the ink holding power becomes stronger.

The same holds true when the porosity decreases; however, the amount of ink passing through during writing is limited, and blurring and fading are more likely to occur.

Generally, when the viscosity of the ink is high or the surface tension is large, the voids are adjusted to be denser and the porosity is increased. It is necessary to adjust the rate to be small,
It is difficult to find the appropriate value.

The ink used in this invention has a viscosity of 10 to 70 cps (2
0°C) surface tension of 30 to 60 dyne/crrL (2
0°C) is optimal.

However, in order to use ink with this physical property,
It has been discovered that the ink derivative described above is necessary.

The anti-backflow agent is a viscous substance that is inserted from the open end of the ink tube in contact with the ink to prevent ink from scattering from the open end of the ink tube caused by impact. 20.000cps
Specify a mixture of petrolatum, liquid paraffin, and silicone oil at (20°C).

The thickness is preferably 2 to 4 Wn.

This viscous mixture is within the temperature range for water-based ballpoint pens (
It does not volatilize at temperatures of 0.8 - 5.0'C) and is not miscible with water since its main component is paraffin.

In addition, since it contains relatively low-molecular liquid paraffin, the amount of ink decreases quickly, and even ink-free water-based ballpoint pens can more effectively follow the amount of ink than a pasty filler such as Vaseline alone. Move the tube.

Furthermore, the silicone oil can sufficiently remove ink stains adhering to the mural on the ink tube 4.

This idea identified the physical properties of the ink that are most suitable for water-based ink ballpoint pens, identified the structure of the ballpoint pen that is suitable for the specific ink, specified the composition of the ink derivative, and the ink backflow prevention agent, and identified the characteristics of the ink that are suitable for conventional water-based ink ballpoint pens. Smoothness and stability of ink spillage, prevention of stains on writing edges,
It is a useful device that exhibits excellent properties in terms of the density of written lines, smooth writing feel, and wear resistance of the tip.

For reference, Table 1 shows comparative examples with typical water-based ink ballpoint pens and oil-based ballpoint pens currently on the market.

[Brief explanation of drawings]

The figure is a longitudinal cross-sectional view of the ballpoint pen of the present invention, and the figure shows 1...a curved ballpoint pen tip, 2...a curved hole, 2c...
...Central hole, 3. Curved ink extractor, 4. Curved ink tube, 5. Ink, 6. Curved ink backflow prevention agent.

Claims (1)

[Scope of utility model registration request] A ballpoint pen in which a porous ink extractor is inserted into the center hole of a ballpoint pen tip into which a ball is fitted, and an ink tube containing ink and an ink backflow prevention agent is connected to the inner end of the tip, in which the porous ink extractor has a diameter of 2 denier to It is a rod made by curing a bundle of synthetic fibers selected from 7-denier polyacrylonitrile synthetic fibers with a thermosetting resin to a porosity of 30 to 50%, and the ink has a viscosity of 10 to 70 cps (20
) and has a surface tension of 30 to 60 dyne/cm (
A water-based ink ballpoint pen whose backflow prevention agent is a mixture of vaseline, liquid paraffin, and silicone oil.