JPH09176553A - Lead of colored pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a colored pencil lead not losing a reinforcing effect and having a good coloring property and a good writing touch. SOLUTION: This non-calcination type lead of colored pencil comprises at least a binder, an extender, a lubricant and a coloring material. Therein, the fibrous product of porous calcium carbonate is used as at least a part of the extender. In the colored pencil lead, a product obtained by adhering the coloring material to the surfaces of the fibrous product of porous calcium carbonate by a dry dispersing treatment method is used. It is estimated that the strength of the lead is strongly generated by an orientation effect due to its shape similarly to the conventional fibrous reinforcing material and further that the colorability of the lead is largely caused by the porous shape. Since the coloring material is adhered to the fibrous product of porous calcium carbonate only with a relatively weak van der Waals force, it is further estimated that the coloring material is sufficiently separated from the fibrous product and subsequently anchored to the surface of paper even with a friction force on writing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-baking type colored pencil lead containing a fibrous material as at least a part of an extender.

[0002]

2. Description of the Related Art Conventionally, a non-sintered type colored pencil lead is mixed with a binder, a coloring material, an extender, a lubricant, and other plasticizers used as necessary, kneaded and molded, and if necessary. It is manufactured by being dried. In particular, it is known to use a fibrous reinforcing material in the core material for the purpose of enhancing the orientation effect of the core body and improving the strength of the colored pencil core used in a sharp pencil having a diameter of 2 mm or less. As a typical example thereof, there is a fibrous material of potassium titanate disclosed in JP-B-62-3189.

For the purpose of reinforcement, the above-mentioned conventionally known various fibrous reinforcing materials are sufficient, but the most important thing in the color pencil lead is color developability. Although the fibrous reinforcing material can improve the strength of the colored pencil lead, the coloring property is deteriorated. This was due to poor wettability between the coloring material and the fibrous material.

In order to improve the wettability with a coloring material, Japanese Patent Laid-Open No. 56-109266 discloses a body material such as talc and mica which is treated in the same manner as the coloring material surface-treated with an organic titanate coupling agent. There is a description about a colored pencil lead using. Certainly, this method can improve the easiness of breaking the core by increasing the wettability between the coloring material and the extender material, but the extender material and the coloring material form a matrix, and therefore, when writing. Since it is fixed on the paper surface as one large coloring material, the appearance is inferior, and at the same time, the writing quality is deteriorated because a large amount of particles are worn away. Even if the fibrous reinforcing material is treated with the coupling agent, the same result will be obtained although there is a difference in the shape of the matrix to be formed.

Further, in the above-mentioned publication, as a concrete method of treating the coupling agent, the coupling agent is added to the surface of the coloring material and the extender of the powder to be treated during high-speed powder mixing by a Hensyl mixer or the like. Although there is a description of treatment, the strength of the colored pencil lead treated by replacing the extender material with the fibrous reinforcing material by this method remarkably decreases. It is presumed that this is because the fibers collide with each other or the coloring material and the fibers break, and the orientation effect during molding is lost.

[0006]

Therefore, the present invention is intended to solve various problems caused by using these conventional fibrous reinforcing materials, in which at least a part of the body material is reinforced with fibrous materials. It is an object of the present invention to provide a colored pencil lead having a good coloring property and a good writing quality without losing the reinforcing effect.

[0007]

The present invention has been made possible by solving the above problems by paying attention to a porous fibrous material of calcium carbonate, instead of the conventionally known fibrous reinforcing material. In general, in a non-fired type colored pencil lead that uses at least a binder, an extender, a lubricant and a coloring material, a colored pencil lead that uses a porous calcium carbonate fibrous material as at least a part of the extender. In the first gist, the colored pencil lead is characterized in that the coloring material is fixed to the surface of the porous fibrous material of calcium carbonate by a dry dispersion treatment. This is the summary of 2.

The method for producing the porous calcium carbonate fibrous material used in the present invention is to uniformly disperse sodium chloride in heavy calcium carbonate, and to prepare 800-1
Pores formed by volatilized sodium chloride are formed by baking at 000 ° C., the porous body is saturated with water vapor, and further dried at 350 ° C. from a relatively low temperature range.
It is obtained by dry carbonation at 750 ° C. in a carbon dioxide gas atmosphere, and its powder properties have an average fiber length of 25 to
30 μm, average fiber diameter of 0.5 to 1.0 μm, total pore specific surface area of 77.0 m 2 / g, average pore diameter of 0.13
9 μm.

In contrast to the fibrous reinforcing material of the present invention, the specific surface area of the conventional fibrous reinforcing material is less than 10 m ² / g, which is almost smooth and has poor wettability, so that the coloring material adheres to the fiber surface. Can not be done and the coloring material is attached to the paper surface while aggregating,
The color developability decreases.

On the other hand, since the porous fibrous material of calcium carbonate has a large specific surface area, it has good wettability with the coloring material even if it is simply mixed at the same time. Therefore, the fibrous material can be efficiently mixed when the coloring material is kneaded. Since it adheres to the surface and the inside, the coloring material does not aggregate in the core body, and the coloring property can be enhanced.

Further, since the structure is such that the pigment particles having an average pore size can easily enter, a general ball mill, a hensyl mixer, a crusher, etc. can be prepared before mixing the porous calcium carbonate fibrous material and the colorant. Since the particles of the coloring material fill the pores of the fiber by performing the dry dispersion treatment with the stirrer in advance,
Since the surface of the fiber is modified by the coloring material and the wettability is further improved, the strength can be further improved by maintaining the concentration more than in the case of simply mixing them at the same time.

It is important that the above-mentioned dry dispersion treatment is carried out to such an extent that the fiber shape is not destroyed.
When the treatment is performed at 18,000 rpm for about 3 minutes, the particles of the coloring material adhere to the surface and the inside of the fiber. Various coupling agents may be used during the dispersion treatment.

The amount of the porous fibrous material of calcium carbonate used depends on the particle size of the coloring material to be used, but is about 10 to 30% by weight, preferably 15% by weight based on the total amount excluding the volatile solvent content. It is preferably about 25% by weight. If the amount of the porous fibrous material of calcium carbonate used is less than 10% by weight, the orientation effect cannot be exhibited and the strength may be decreased.
When the amount used exceeds 0% by weight, the strength may be improved but the color developability may be deteriorated.

Other than the above-mentioned porous fibrous material of calcium carbonate, conventionally known materials can be used, and the binder can be synthetic or natural resin. For example, cellulose derivatives such as carboxymethyl cellulose, nitrocellulose, cellulose acetate, and cellulose nitrate, polymethyl methacrylate, polyvinyl alcohol, polyvinyl butyral, polyethylene, epoxy resin, polychlorination. Examples thereof include vinyl, vinyl chloride-vinyl acetate copolymer, polystyrene, acryl-styrene copolymer, acryl-styrene-butadiene copolymer, tragacanth gum, gum arabic, and guar gum.

As the extender, conventionally known materials can be used, but those having good crystallinity so as not to disturb the orientation effect at the time of molding are preferable, and talc is also wet-ground, and Boron nitride, graphite fluoride, Nε
-Lauroyl lysine etc. are mentioned.

As the coloring material, various inorganic and organic pigments can be used without distinction, but it is preferable to use a pigment having a size equivalent to the pore size of the surface of the porous calcium carbonate fibrous material. desirable.

As the lubricant, conventionally known lubricants can be used. For example, stearic acid, stearic acid metal salt, etc., and various aspartic acid esters, etc. can be used as the amino acid lubricant.

Other materials include paraffin wax, microcrystalline wax, zinc stearyl ketone, montan wax, polyethylene wax, carnauba wax, wood wax, beeswax and the like, natural wax, diallyl phthalate, tricresyl phosphate, Polycarbonate
Various plasticizers such as bone and solvents such as methyl ethyl ketone can be appropriately used as the compounding material.

[0019]

The strength is largely due to the orientation effect due to the shape like the conventional fibrous reinforcing material, and the color development is considered to be largely due to the porous body. This is because the coloring material and the porous fibrous material of calcium carbonate are fixed to each other only by the comparatively weak van der Waals force, so that the coloring material is sufficiently fixed on the paper surface even by the frictional force during writing. Seem. Further, the strength improvement by dry-dispersing the coloring material and the porous fibrous material of calcium carbonate is that the coloring particles are forcibly embedded in the pores of calcium carbonate, whereby the fiber surface is modified, Further, it is considered that the wettability is enhanced and the denseness of the core is improved, and it is also considered that the strength of the fiber itself is improved because the colorant particles are embedded in the pores of the fiber by the dry dispersion. It is considered that the writing quality is good because the low strength of calcium carbonate itself tends to self-disintegrate due to the frictional force during writing.

[0020]

【Example】

<Example 1> Nitrocellulose 21 parts by weight Porous calcium carbonate fibrous material (BS-P; sold by Shikoku Chemicals Co., Ltd.) 20 parts by weight Wax 3 parts by weight Nε-lauroyl lysine 30 parts by weight Aluminum steare -To 4 parts by weight Phthalocyanine blue-19 parts by weight Polycarbonate 3 parts by weight Methyl ethyl ketone 100 parts by weight After kneading the above materials while adjusting the amount of solvent with three rolls,
It was extruded into a thin wire and dried in a dryer at 80 ° C. for about 8 hours to remove the solvent, and a blue core for a sharp pencil having a nominal diameter of 0.9 was obtained.

<Example 2> Before compounding in Example 1, the porous fibrous material of calcium carbonate and the phthalocyanimble were mixed with a small crusher (SK-M10 manufactured by Kyoritsu Riko Co., Ltd.) to about 1 part.
A blue core was obtained in the same manner as in Example 1 except that a material subjected to dry dispersion treatment at 6,000 rpm for 3 minutes was used.

<Examples 3 to 8> In all of Example 1 except that the amount of porous calcium carbonate fibrous material was changed from 20 parts by weight to 5, 9, 15, 26, 33, 37 parts by weight. A blue core was obtained in the same manner as in Example 1.

<Example 9> In Example 2, the organic titanium coupling material (KENRICH PETROCHEMICAL IN was used for dry dispersion with a small crusher.
A blue core was obtained in the same manner as in Example 2, except that 0.2 part by weight of KR-TTS manufactured by Company C) was dropped and the surface-treated material was used.

Comparative Example 1 A blue core was obtained in the same manner as in Example 1 except that the fibrous material of calcium carbonate was used instead of the fibrous material of porous calcium carbonate in Example 1.

Comparative Example 2 A blue core was obtained in the same manner as in Example 1, except that the fibrous material of potassium titanate was used in place of the fibrous material of porous calcium carbonate in Example 1.

Comparative Example 3 A blue core was obtained in the same manner as in Example 2, except that the fibrous material of calcium carbonate was used instead of the fibrous material of porous calcium carbonate.

Comparative Example 4 A blue core was obtained in the same manner as in Example 9 except that the fibrous material of calcium carbonate was used instead of the fibrous material of porous calcium carbonate in Example 9.

The bending strength of the colored pencil lead obtained in each of the above examples,
Table 1 shows the test results of color developability and writing quality. Bending strength is JI
Measured according to the measurement method of S S6005 (Unit: MP
a), the color development is the same as the density of the writing line according to JIS S600.
5 densitometry was followed (unit is D). The writing quality is a numerical value of the resistance of the core to the copper plate when a holder containing a color core in the shape of a copper disk is set vertically using a dynamic friction tester and the disk is rotated with a load of 400 g. The lower the value, the better the writing.

[0029]

[Table 1]

[0030]

As shown in Table 1, the colored pencil lead of the present invention is different from the conventional fibrous reinforcing materials in that it does not deteriorate the coloring property and the writing quality due to the improvement in strength, and the colored pencil lead has further improved strength. Can be provided.

Claims (2)

[Claims] 1. In a non-fired type colored pencil lead which uses at least a binder, a body material, a lubricant and a coloring material, a porous calcium carbonate fibrous material is used as at least a part of the body material. Colored pencil lead. 2. The colored pencil lead according to claim 1, wherein a coloring material is fixed to the surface of the fibrous material of the porous calcium carbonate by a dry dispersion treatment.