JPH10893A - Water base ink-containing ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce occurrence of a skip even in case of a long term stock by incorporating water base ink containing titanium oxide, and forming an elastic member of a nitrle rubber. SOLUTION: Water base ink 3 containing titanium oxide is contained in an ink containing tube 1. The ink 3 containing the oxide contains titanium oxide, water and a thickening material as well as, as required, a pigment, a dye, a water soluble organic solvent, a dispersant, a wetting agent, an antiseptic and a lubricant. An elastic member 7 for embedding to seal a nib tip in case of mounting a cap 5 is disposed in the cap 5. The member 7 is indispensably formed of a nitrile rubber as its material to prevent growth of a bubble due to invasion of the air into a ballpoint pen tip at the time of stocking. Thus, even after a long term stock, occurrence of a skip can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen containing a water-based ink containing titanium oxide and having a cap in which an elastic member for sealing a pen tip is disposed. More specifically, the present invention relates to a ballpoint pen containing an ink containing titanium oxide, which suppresses the growth of mixed air over time by writing and causes less blurring even after long-term storage.

Hitherto, for the purpose of preventing drying of the pen tip and preventing ink from flowing out of the pen tip, there have been proposed many caps in which an elastic member is provided to come into contact with the tip of the pen tip. For example, Japanese Utility Model Publication No. 2-5994 discloses an aqueous ballpoint pen cap in which a stopper made of a soft elastic material is fixed. Also, registered utility model 3000
No. 261 also discloses a cap for a ballpoint pen in which the tip of the pen body of a ballpoint pen is embedded and sealed in a soft elastic body loaded therein. Regarding the material of the elastic member which abuts on the tip of the pen tip to seal the pen tip, for example, Japanese Patent Publication No. 64-11476 discloses soft polyvinyl chloride,
It is disclosed that a soft material such as silicone rubber or polyurethane elastomer is preferred.

[0003]

The blurring of handwriting due to bubbles grown in a ballpoint pen tip. In general, when writing on a ballpoint pen, air is easily drawn in from the tip orifice at the tip of the penpoint, and air penetrates into the ink in the ballpoint pen tip. In particular, a ball-point pen tip for water-based ink has a large clearance at the tip of the pen tip, so that it is easy to entrain air. The air that has penetrated into the ballpoint pen tip becomes bubbles in the ink. However, if air bubbles are generated by the air entrained at the time of writing, the air does not fade when writing. However, since the elastic member made of the above-mentioned material used for preventing the pen tip from drying or preventing the ink from flowing out of the pen tip has a high air permeability, air that has penetrated the elastic member and penetrated into the ball-point pen tip causes air bubbles. Grows and grows. As a result, the ink conduction hole inside the ballpoint pen tip is filled with air bubbles, which obstructs the flow of the ink, so that blurring is likely to occur. The degree of blur depends on the type of ink. In the case of using a low-viscosity aqueous ink using a general pigment such as carbon black, the degree of blurring is small because the ink has high fluidity. However, especially in the case of ink using titanium oxide, it is necessary to set the viscosity of the ink to be high in order to prevent sedimentation of titanium oxide. Therefore, the fluidity of the ink is poor, and the degree of blurring is very large.

[0004] It is an object of the present invention to provide a ballpoint pen containing a water-based ink containing titanium oxide, which minimizes the growth of air bubbles mixed by writing over time and causes little blurring even when stored for a long period of time. That is.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a ballpoint pen having a cap in which the tip of the penpoint of a ballpoint pen is buried and sealed in an elastic member disposed inside, wherein the ballpoint pen is made of an aqueous ink containing titanium oxide. Built-in,
The ballpoint pen with a built-in aqueous ink is characterized in that the elastic member is made of nitrile rubber.

Hereinafter, the present invention will be described in detail. The attached drawings show an embodiment of the ballpoint pen according to the present invention, and the present invention is not limited to this. FIG.
The ink storage tube 1 is a transparent or translucent ink storage tube made of a synthetic resin such as polyethylene or polypropylene. In order to prevent the ink from adhering to the ink storage tube, the ink storage tube 1 is water- and oil-repellent with silicone oil or the like. May be processed. A ball point pen tip 2 made of a nickel-white, stainless steel, brass, resin or the like serving as a pen tip is fixed to one end of the ink storage tube 1. As the ball, a material such as tungsten carbide or silicon carbide can be used. The shape of the ball pen tip 2 is not particularly limited, and a conventionally known shape such as a shell type or a pipe type can be used.

A water-based ink 3 containing titanium oxide is stored in the ink storage tube 1. The aqueous ink 3 containing titanium oxide was composed of titanium oxide, water, and a thickener, and contained pigments, dyes, water-soluble organic solvents, dispersants, wetting agents, preservatives, lubricants, and the like as needed. Things.

At the rear end side of the aqueous ink 3 containing titanium oxide, an ink backflow preventer 4 that is incompatible with the aqueous ink 3 containing titanium oxide is accommodated. The ink backflow preventive body 4 is composed mainly of a hardly volatile organic liquid selected from hydrocarbons, a non-volatile organic liquid, or silicone oil or silicone grease, and is made into a gel. If necessary, a surfactant or the like may be used in combination for the purpose of preventing adhesion to the ink storage tube.

The cap 5 is made of a synthetic resin such as polyethylene or polyethylene terephthalate, and is detachably attached to the shaft cylinder 6 which is a ballpoint pen body. Inside the cap, there is disposed an elastic member 7 in which the tip of the pen tip is buried and sealed when the cap 5 is attached. In this embodiment, the shape of the elastic member 7 is exemplified by the one having a substantially bale-shaped cross section, but the shape is not particularly limited, and for example, a spherical or plate-like one can be used. Further, a concave portion may be provided in the contact portion with the pen tip in order to improve the adhesion to the tip of the pen tip. The elastic member 7 is required to be made of nitrile rubber. This is to prevent the growth of bubbles due to the intrusion of air into the ballpoint pen tip during storage.

[0010]

The ballpoint pen according to the present invention uses an aqueous ink containing titanium oxide as an ink, but uses nitrile rubber as an elastic member for sealing the pen tip.
Since the nitrile rubber has low air permeability, the invasion of air from the outside is slight, and the growth of bubbles can be almost neglected.

[0011]

The present invention will be described below in more detail with reference to examples. Example 1 A ballpoint pen tip made of tungsten carbide and having a ball having a diameter of 0.8 mm and a stainless steel ballpoint pen tip 2 was made of polypropylene and had an outer diameter of 60 mm.
One end of an ink containing tube 1 having an inner diameter of 40 mm and a length of 120 mm was filled, and the ink containing tube was filled with 1.2 g of an aqueous ink 3 containing the following titanium oxide and 0.15 g of an ink backflow preventer 4. The ink storage tube 1 was inserted into a shaft cylinder 6 made of a styrene acrylonitrile copolymer and assembled to obtain a ballpoint pen body. A cap 5 made of polyethylene terephthalate, in which an elastic member 7 made of nitrile rubber was disposed so that the tip of the tip of the ball-point pen was buried when the ball-point pen was mounted, was formed into a ball-point pen body.

(Water-based ink containing titanium oxide) Kronos KR380 (manufactured by Titanium Industry Co., Ltd.) 36.0 parts by weight LUMIKOL NKW2108 (colored pigment, resin particles colored blue, solid content 53% by weight, Nippon Fluorescent Co., Ltd.) 20.0 parts by weight Joncryl J61J (ammonium salt of styrene-acrylate copolymer, manufactured by Johnson Polymer Co., Ltd.) 17.0 parts by weight Kelzan AR (Xanthan gum, Sansheng Co., Ltd.) 0.6 parts by weight Water 36.4 parts by weight Ethylene glycol 5.0 parts by weight Glycerin 5.0 parts by weight Among the above components, components other than LUMIKOL NKW2108 and Kelzan AR are mixed and dispersed in a ball mill for 24 hours. Is performed, LUMIKOL NKW210
8. Add Kelzan AR and stir for 1 hour.
000 cps (E type viscometer, st rotor, 1 rpm,
(25 ° C.) to obtain an aqueous ink containing titanium oxide.

Comparative Example 1 A ballpoint pen was prepared in the same manner as in Example 1 except that the elastic member made of nitrile rubber was made of silicon rubber.

Comparative Example 2 A ballpoint pen was prepared in the same manner as in Example 1 except that the elastic member made of nitrile rubber was made of ethylene propylene terpolymer.

Reference Example 1 Comparative Example 1 was the same as Comparative Example 1, except that the following black aqueous ink was used in place of the aqueous ink containing titanium oxide.
I made a ballpoint pen in the same way as. (Black aqueous ink) Carbon black 10.0 parts by weight Dispersant (α-methylstyrene-acrylic acid copolymer) 5.0 parts by weight Ethylene glycol 14.0 parts by weight Glycerin 5.0 parts by weight Thickener (Gar gum) 0.8 parts by weight Preservative 0.2 parts by weight 25% aqueous solution of sodium hydroxide 1.0 part by weight Water 64.0 parts by weight
After mixing and stirring for 0 minutes, the mixture is further dispersed with three rolls. Thereafter, coarse particles were removed by centrifugation, gar gum was added thereto, and the mixture was stirred for 1 hour to obtain a black ink. The viscosity of the ink is 2000 cps (25 ° C.).

As described above, Example 1, Comparative Examples 1 and 2, Reference Example 1
Using each of the ballpoint pens obtained in the above, one sheet (4
(00 characters) I wrote and confirmed that I could write without blurring. The ballpoint pen was allowed to stand for one month in a constant temperature room at 50 ° C. with the pen tip facing upward, and was then written on original paper again. Table 1 shows the results.

[0017]

[Table 1]

[0018]

As described in detail above, the ballpoint pen according to the present invention is a ballpoint pen containing a water-based ink containing titanium oxide having low fluidity, but is a nitrile rubber having low air permeability. Made of elastic member,
Since the cap disposed inside is used, the invasion of air into the pen tip can be prevented, and as a result, bubbles in the ballpoint pen tip do not grow, so that the occurrence of blurring even after long-term storage can be suppressed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink storage tube 2 Ball-point pen tip 3 Water-based ink containing titanium oxide 4 Ink backflow prevention body 5 Cap 6 Shaft cylinder 7 Elastic body

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Naoki Sato 229-1 Kamitamari, Tamari-mura, Niiji-gun, Ibaraki Prefecture Pentel Co., Ltd.

Claims (1)

[Claims] A ballpoint pen having a cap in which an end of a pen point of a ballpoint pen is embedded and sealed in an elastic member disposed inside, wherein the ballpoint pen contains a water-based ink containing titanium oxide, and the elastic member is A ballpoint pen with a built-in water-based ink, characterized by being made of nitrile rubber.