Mitsubishi Pencil Kabushiki Kaisha

Youji Takeuchi

Kiyoshi Iwamoto

Tadashi Kamagata

Katsuhiko Shiraishi

Norio Ogura

Masaru Miyamoto

Shigeru Miyazaki

In a ballpoint pen which is formed to have an ink-consumption value per unit area of 0.64 to 1.6 mg/cm , the surface tension of the ink for the ball point pen is adjusted to a range of 16 to 32 mN/m so that blotting, line splitting and the like hardly occur, that the ink transferred onto the paper surface is ready to be dried and that fluctuation in the density and width of the written lines are less likely to occur due to a storage environment and to a writing condition.

Ink for ball-point pen and ball-point pen

In a ball pen which is formed to have an ink-consumption value per unit area of 0.64 to 1.6 mg/cm , the water content is adjusted in the range from 30.0 to 80.0 wt %, the content of a volatilization-inhibiting substance in the range from 0.1 to 10.0 wt % and the content of a hardly-volatile water-soluble liquid medium in the range from 1.0 to 40.0 wt % in the ink for a ball pen in order to achieve both the quick-drying property of the ink transferred onto the paper surface and the non-drying property of the point of the pen-tip and further a good writing feeling.

Ink for ball pen and ball pen

Dispersibility of thickener is constant for every lot and viscosity difference is little. Fine bubbles existing in the thicker in ink follower are removed. A step of homogenizing the thickener at any temperature within a range of 40&deg; C. to 130&deg; C. is included. Preferably, a step of homogenizing the thickener at any temperature within a range of 100&deg; C. to 130&deg; C. is included.

Method for manufacturing ink follower for water base ballpoint pens

This invention relates to ink follower for a water-base ballpoint pen with its bubbles removed, time-dependent stability, less oil separation, and greatly reduced lot-to-lot viscosity difference and associated performance difference, and a method for manufacturing the same. After addition of thickener, the follower is made depressurized preferably at 0.2 atm or lower. Simultaneous heating and stirring are preferable. When the ink follower is solely debubbled in advance, fine bubbles contained in particulate silica, clay thickener, etc. can be very highly removed even if the centrifugal debubbling is not so strong and there is no bad affection to the writing property of the pen. It is also possible that, after adding the thickener, a centrifugal force greater than or equal to 200-fold of the gravitational acceleration is applied to debubble.

Ink follower for water-base ballpoint pens and method of manufacturing the same

Lot-to-lot or time-dependent instability in quality of the known ink follower for water-base ballpoint pens is overcome. Particulate silica, or organic-treated clay is kneaded as thickener with base oil to prepare gel matter. The gel matter is pressurized to eliminate fine bubbles to yield ink follower for water-base ballpoint pens. The pressurization is preferably performed at 2 atm or higher. The elimination of the bubbles is more effective when the ink follower is, under pressurization, stirred and/or heated.

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Yokohama, Japan

Youji Takeuchi