JP3267355B2 - Colored lead - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintered type color lead core, which is characterized by using fluorine-based mica as a material.

[0002]

2. Description of the Related Art Colored lead cores are classified into sintered type and non-sintered type, and the sintered type is superior in strength and writing taste.
In recent years, various methods for improving these performances have been studied. Here, the sintered type color lead core is composed of a body material and a binder as its material, and boron nitride, talc, and the like are used as the body material, and clay is typically used as the binder. . However, conventional color lead cores have not yet obtained sufficient strength and writing taste. Even if the strength is improved by increasing the binder, the writing taste and the color tone density are conversely inferior.

Attempts have been made to improve the strength by using various binders. For example, aluminum phosphate and organosilicon compounds, furthermore, boron and its compounds are nitrided, or silicon nitride or aluminum is used. The use of such nitrides is known.

[0004]

However, aluminum phosphate contains P ₂ O ₅ which is harmful to the human body, and organosilicon resin is more pure in its components than clay, but has sufficient strength and writing taste. Color lead has not been reached. As for other binders, a color lead having high strength and a good balance between writing quality and density has not yet been obtained. Although the reason for this is not clear, at the normal lead core firing temperature (around 1000 ° C.), nitrides of silicon and aluminum do not show sufficient sintering properties, and have low strength. It is presumed that, when sintering at a higher temperature in order to increase the carbon content, unlike the carbon skeleton in the black core, the skeleton itself shows the characteristics of fine ceramics, becomes hard, and deteriorates in writing taste and concentration. .

[0005]

SUMMARY OF THE INVENTION The present invention solves the problem of the conventional color lead core. By using synthetic mica as a material for the color lead core, the density can be maintained while maintaining sufficient strength. It is intended to provide a well-balanced colored lead core which is dark and has good writing characteristics, and is characterized by using a fluorine-based mica as a constitutional material and / or a binder.

The fluorine-based mica used in the present invention is obtained by replacing water of crystal (OH) in a crystal of natural mica with fluorine (F), and its general formula is X _a Y _b Z ₄ O ₁₀ ( F
₂ ). Here, a is 0.5 to 1.0 and b is 2 to 3. Further ions that can be substituted at the XYZ position are as follows. X: +1 valence ion of Na, +1 valence ion of K, Ca
+ Divalent ion of Ba + divalent ion of Sr, + divalent ion of Sr Y ... + divalent ion of Mg, + divalent ion of Fe, N
+2 valence ion of i +3 valence ion of Al, +3 valence ion of Fe, +1 of Li
Charged ions Z: +4 charged ions of Si, +4 charged ions of Ge, A
+ trivalent ion of l + trivalent ion of Fe, + trivalent ion of B

For example, as a specific example, fluorophlogopite "K
Mg_Three(AlSi_ThreeO_Four) F_TwoAnd fluorinated tetrasilicic mica
"KMg_2.5(Si_FourO_Ten) F_Two”, Teniolite“ K
Mg _TwoLi (Si_FourO_Ten) F_TwoAnd more.
Has the property of absorbing water and metal and swelling
Silicic mica "NaMg_2.5(Si_FourO_Ten) F_Two"
Or Na or Li hectorite "(Na, Li)
_1/3Mg_8/3Li_1/3(Si_FourO_Ten) F_TwoAnd N
a or Li teniolite "(Na, Li) Mg_TwoL
i (Si_FourO_Ten) F_TwoAnd the like.

These fluorinated mica are white, chemically pure, have extremely stable properties, have lubricity, are stable in heat resistance up to 1000 ° C., and exhibit sinterability. Has features.

On the other hand, natural mica, which has been conventionally used as a body material of a color lead core, has a structure containing water of crystallization in the crystals, and therefore, releases water of crystallization from about 600 ° C. and collapses. It becomes easily unstable and chemically unstable because it is a natural product. However, since it has lubricating properties, it can be used as a core material. However, since its heat resistance is low, a sintered type color lead core is not always suitable for use.

The fluorine-based mica used in the present invention has lubricity and sinterability by itself, and therefore can be used alone as a color lead core material. Here, in order to obtain a colored lead core, a method of impregnating a fluorine-based mica with a heat-resistant pigment and / or ink into pores of the obtained sintered body can be used.

Here, in addition to the above, there is also the following method for making a colored lead core. That is, as described above, some fluorine-based mica has the property of swelling by taking in water or metal between molecules, and is structurally opposed to an oxygen negatively charged surface (only 12-coordinate oxygen). ), The swelling property is exhibited when a +1 valent ion of Na or a +1 valent ion of Li is present, and when water is taken in, Na or L
At the same time as the center of the metal ion i, water molecules are hydrogen-bonded to oxygen, and a water molecule layer in the form of a hexagonal network of hydrogen bonds is formed between oxygen negatively charged surfaces. At this time, the two oxygen negatively charged surfaces are separated. From the above properties, for example, cationic dyes other than water and metal, such as Na or L
It is also possible to exchange with the metal ion of i and take in,
As a result, colored mica is obtained. Therefore, without using a heat-resistant pigment or ink as a coloring material,
This makes it possible to produce colored lead cores.

Further, the purpose of use of the fluorine-based mica can be appropriately set depending on the particle size. In other words, when the demand as a binder is strong, the smaller the particle size, the better the particle size is, for example, 1 μm or less. Also, when the use as a constitutional material is strong, the larger the particle size, the better. For example, 1 μm or more, especially 5 μm or more is considered to be good. However, the fluorinated mica of the present invention includes the properties as a binder and a body material at any particle size, and is not strictly defined by the above-described limitations. Just set it.

Next, according to the usage of the fluorine-based mica,
Conventionally known constitutional materials and binders may be added and used. By adding the filler to the fluoromica, the lubricating properties of the filler and the fluoromica itself are added, so that a very good writing quality can be obtained.By adding the binder and the fluoromica, fluorine is added. Since the lubricating property of the series mica is maintained up to a high temperature, the fluorine series mica itself also has a sintering property, so that a strong writable and strong strength can be obtained. Further, compared to clay and the like, fluorine-based mica contains no impurities, so that a pure white porous sintered body can be obtained, and as a result, a color lead core having a vivid color tone can be obtained.

Examples of the extender include boron nitride, talc, titanium oxide, silica, alumina, natural mica, calcium carbonate and the like, and these can be used alone or in combination.

Other binders include kaolinite-based, sericite-based, montmorillonite-based, bentonite-based clay, zeolite, diatomaceous earth, activated clay, silica, aluminum phosphate, silicone resin, silicone rubber, and the like. No.

Using the above materials, kneading, extrusion,
It is fired to produce a sintered body, and the obtained pores are impregnated with oil, ink, or the like to obtain a colored lead.

At this time, at the time of kneading, in addition to the above materials,
An organic polymer compound may be added. By adding, the bonding force at the time of extrusion is improved, and at the same time, by removing the resin in an oxidation treatment or an inert atmosphere at the time of firing,
A porous sintered body is obtained. Examples of the organic polymer compound include waxes, synthetic resins, natural resins, natural and synthetic rubbers, depolymerized resins, pitch, asphalt, and the like.

Further, a fibrous substance such as carbon or resin may be added at the time of kneading and removed at the time of firing to form pores. Next, examples of the present invention will be described. Here, parts are parts by weight.

[0019]

【Example】

Example 1 Fluorine-based mica (average particle diameter 0.5 μm) 40 parts (average particle diameter 10 μm) 60 parts (high-purity fluorine tetrasilicic mica) Polyvinyl alcohol 15 parts Water 100 parts The above-mentioned material was kneaded with a kneader and three rolls. Then, the water content was adjusted. This was extruded into a thin wire to produce a colored lead core extruded material. Next, the extruded material is dried at 100 ° C. for 24 hours or more, and then heated in air at a rate of 50 ° C./hr, 800 ° C.
And then calcined at 800 ° C. for 5 hours to remove carbon content and sinter the fluorine-based mica to obtain a white porous sintered body. This porous sintered body was immersed in a ballpoint pen-based red ink and left at 70 ° C. under reduced pressure for 24 hours. The sintered body impregnated with the ink was washed with alcohol to complete a red lead core having a nominal size of 0.5 mmΦ. In this colored lead, the fluorine-based mica contributed as a binder and a body material, and was composed of the fluorine-based mica and the red ink impregnated in the pores, and had a strength of 175 MPa. Also, its color tone is because the obtained porous sintered body is pure white,
It became dark and vivid.

Example 2 Fluorine-based mica (average particle size: 0.5 μm) 40 parts (high-purity fluorinated tetrasilicon mica) Boron nitride (lubricant) 60 parts Polyvinyl alcohol 15 parts Water 100 parts Using the above materials, sintering temperature 800 A colored lead was prepared in the same process as in Example 1 except that the temperature was changed to ° C. In this color lead,
Fluorine-based mica contributes as a binder, and is composed of fluorine-based mica, boron nitride, and a red ink impregnated in pores, has a strength of 169 MPa, and has a smooth writing feel. The color tone was deep and vivid because the porous sintered body was pure white.

Example 3 Fluorine-based mica (average particle size: 5 μm) 20 parts (average particle size: 0.5 μm) 20 parts (fluorphlogopite) Boron nitride (lubricant) 40 parts Clay (binder) 20 parts Polyvinyl alcohol 15 Part Water 100 parts Using the above-mentioned material, a colored lead was produced in the same process as in Example 1. In this color lead, the fluorine-based mica contributes as a constitutional material and a binder, and is composed of a fluorine-based mica, boron nitride, clay, and a red ink impregnated in pores. The taste is very smooth and good.

Comparative Example 1 In place of the fluorine-based mica of Example 2, clay was used as a binder, and a porous sintered body was formed in the same process as in Example 1.
The red ink was impregnated to produce a red colored lead core. This colored lead had a strength of 110 MPa, and the obtained porous sintered body became light brown due to a large amount of clay, and did not have a vivid color tone.

[0023]

As described above, in Example 1, a good color lead was obtained by using fluorine-based mica as a main component. In Examples 2 and 3, boron nitride as a body material and clay as a binder were added to the fluorine-based mica, respectively. In each case, the color tone was bright, dark, and had a smooth writing taste while maintaining sufficient strength. Further, the fluorine-based mica used in the present invention is white, and is pure and chemically stable as compared with ordinary natural mica, so that the obtained color lead core can obtain a clear color tone and at the same time, the quality is stable. In addition to having sinterability as a binder and lubricating properties, the writing quality is dramatically improved while maintaining the strength that can withstand writing compared to conventional ones. .

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C09D 13/00

Claims (1)

(57) [Claims] 1. A sintered color lead comprising at least a body material and a binder, wherein a fluorine-based mica is used as the body material and / or the binder.