JPH11310745A - Production of color pencil lead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a color pencil lead excellent in all of the properties including strength, color development, and suitability for writing. SOLUTION: There is provided a process for producing a non-baked color pencil lead, which comprises using a binder which shapes a pencil lead, a body extender, a colorant, and a lubricant as the essential components; using a fibrous material as part of the body extender; kneading these components; molding the mixture; and suitably drying the molding, wherein the fibrous material used is one precoated with a binder which is incompatible with the binder which shapes a pencil lead in molding, and the binder with which the fibrous material is precoated is removed to leave pores after drying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a colored pencil lead using at least a binder, a body material, a coloring material, and a lubricant.
In particular, the present invention relates to a method for producing a non-fired type color pencil lead suitable for use with a mechanical pencil having a fine core diameter of, for example, 2 mm or less.

[0002]

2. Description of the Related Art Heretofore, non-fired type color cores for mechanical pencils having a fine core diameter of, for example, 2 mm or less have been made of polyvinyl chloride, nitrified cotton, carboxymethyl cellulose, and the like.
Binders such as acrylic styrene, coloring materials such as inorganic and organic dyes and pigments, body materials such as talc, mica, calcium carbonate, Nε-lauroyl lysine, and fibrous materials of magnesium sulfate hydrate, titanium Fibrous materials such as potassium acid fibrous materials and titanium oxide fibrous materials; higher fatty acids such as stearic acid, various metal stearic acids, and amino acid aspartic esters; and natural materials such as carnauba wax, beeswax, and wax. Wax, paraffin wax,
It is manufactured by using at least a lubricant such as a synthetic wax such as a microcrystalline wax as a main material and kneading and molding with a plasticizer or various organic solvents as necessary.

[0003]

In order to improve the coloring properties of the conventional color pencil lead, it is sufficient to simply increase the amount of the coloring material, but the strength of the lead tends to become brittle. . Therefore, in order to improve the color developability without changing the amount of the coloring material, it is sufficient to increase the amount of wear when the core is worn by writing, and depending on the compatibility with the binder, carnauba wax, paraffin It is conventionally known that the combined use of waxes such as wax, polyethylene wax and microcrystalline wax with higher fatty acid esters such as stearic acid and metal stearic acid suppresses the strength reduction and improves the color developability. However, when the core diameter is 2 mm or less and a color core for a mechanical pencil is used, even if an attempt is made to obtain color development by using these waxes and ester compounds in combination, the core diameter is small and the strength is greatly reduced.

In order to overcome this problem, a fiber material such as potassium titanate is used in combination with a binder in addition to a binder in order to obtain further strength without deteriorating the coloring property. It is known that the strength is improved by utilizing an orientation effect in which fibers are aligned in the extrusion direction. Certainly, the use of fibrous materials can provide strength enough to withstand writing, but there is a problem that the writing quality is reduced because the fibrous materials are caught on the paper surface during writing.

When a fibrous material is worn on a paper surface by writing, unlike a plate-like crystal such as talc or mica which has a self-abrasive property, it is a needle-like crystal and thus has a low self-abrasiveness. It can be said that it is caused by low things. Therefore, a substance that allows the fibrous material to be easily detached from the core may be placed in the vicinity of the fibrous material, but substances such as various waxes and stearic acid that have a lubricating effect on the surface of the fibrous material have been used so far. Various means of encapsulation have been taken.However, it is necessary to arrange a substance having a lubricating effect in the vicinity, probably because the capsule is broken by rolls, hensyl, etc. when dispersing and kneading the materials. However, a color core with improved writing taste has not been obtained.

Therefore, the present invention differs from the conventional case where a lubricating material such as wax is coated by using a plurality of types of bonding materials and using a material in which the surface of the fibrous material is coated with one of the bonding materials in advance. In addition, since the binder resin that forms the pores strongly adheres to the surface of the fibrous material, the resin can be molded without peeling due to shear stress applied to the material during dispersion and kneading. After forming the core, removing the binder on the surface of the fibrous material, forming microscopic pores such that the core self-disintegrates due to friction during writing, and further impregnating the pores with an oily substance. Thus, at the time of writing, the fibrous material is abraded from the core body, thereby improving the writing taste and further improving the color developing property.

Conventionally, as a technique for forming pores in a color core, Japanese Patent No. 2641810 and Japanese Patent No. 272619 have been disclosed.
No. 8 is known. The former uses a water-repellent and oil-repellent substance such as boron nitride, graphite graphite, carbon fluoride, and fluororesin as a part of the composition in a non-fired type color core, and forms the core into a wet core. The pores are formed in the core body by utilizing the poor property, and the pores are impregnated with fats and oils. The latter uses a material in which at least one of the pigment and the extender is entirely or partially coated with a fluorinated aromatic compound composed of pitch fluoride and seven or less rings, and the fluorinated aromatic compound has a wettability. The pores are formed by utilizing the poor properties of the ink, and oils and fats are impregnated in the pores to provide a color core excellent in writing taste and coloring.

According to these prior arts, open pores are formed by a water-repellent and oil-repellent substance, and by impregnating oils and fats having a lubricating effect therewith, it is possible to improve color development and writing taste. Boron nitride, fluorinated graphite and carbon fluoride are expensive, and the process of preparing pigments and extenders coated with a fluorinated aromatic compound or the like becomes very complicated. The pores are formed by utilizing the poor wettability of these water-repellent and oil-repellent substances. Therefore, the mechanical strength of the core is weak, and if the core diameter does not exceed 3 mm, it tends to withstand use. Depending on the combination of binders and extenders used when molding to less than 2 mm, the water- and oil-repellent material segregates in the core, causing variations in the pore distribution, resulting in mottled handwriting. I will.

The present invention uses a resin that is not compatible with the bonding that forms the core, instead of forming pores with a water- and oil-repellent substance, and uses the resin to cover the surface of the fibrous material with the resin. After molding, the resin is removed from the surface of the fibrous material to form pores, which is different from the above-described conventional technology. Unlike those which are liable to cause segregation, pores having no variation can be formed.

[0010]

Accordingly, the present invention is particularly suitable as a color core for a mechanical pencil having a core diameter of, for example, 2 mm or less. An object of the present invention is to provide a method for producing a color pencil lead having excellent strength, color developability, and writing characteristics, in place of the conventional color lead which has reduced taste and color developability.

A conventional non-fired type color core having a core diameter of 2
The writing mechanism of the color core for mechanical pencils of mm or less is that the load applied vertically to the color core and the lateral load moving in the vertical, horizontal, and vertical writing directions are simultaneously applied to the tip, so that the end face of the core is a fiber convex part on the paper surface. At this time, the body material, such as talc or mica, which is close to a plate crystal comes into contact with the side of the crystal against the load applied vertically, but the fibrous material is a needle-shaped crystal, Crystal tip against load,
That is, they make contact at points. Due to this difference, the writing quality and color developability of the conventional color core have been reduced, and when a lateral load is applied to this, the talc or mica body material wears as the load propagates on the surface and peels off from the core. On the other hand, the fibrous material is worn away from the core. This lowers the writing taste and coloring.

The inventor of the present invention has made it clear how efficiently the coloring material and the writing taste of the color core can be separated from the core material by efficiently removing the coloring material and the needle-shaped crystalline material such as potassium titanate. As a result of extensive research on the mechanism of wear of the color core, we formed pores near the fibrous material that did not cause a decrease in strength, and further provided a lubricating effect on the pores. The present inventors have found that it is necessary to interpose a substance having the same and completed the present invention.

That is, the present invention provides a binder for forming a core,
A body material, a coloring material, and a lubricant are used at least, and a fibrous material is used as a part of the body material, and these are kneaded, molded, and dried in a non-fired type color pencil lead that is appropriately dried. As the fibrous material, a material whose surface is previously coated with a binder that forms the core and a binder that is incompatible at the time of molding is used, and after drying, the binder that is coated on the fibrous material is removed. The first aspect is a method for producing a colored pencil lead having pores formed therein. In the first aspect, a binder for shaping a lead and a binder which is incompatible with the binder at the time of molding are formed of water. The second aspect is a method for producing a colored pencil lead, which is a combination of a water-soluble resin and a water-insoluble resin. In the second aspect, the method for producing a colored pencil lead, wherein the water-soluble resin is a resin having thermoplasticity, is described in a third aspect. A binding material for shaping the core according to the first feature, A fourth aspect of the present invention is a method for producing a color pencil lead, in which a binder and a binder which are not compatible at the time of molding are a combination of water-insoluble resins. The method for producing a colored pencil lead, in which a binder and a binder incompatible at the time of molding are a combination of water-soluble resins, has a fifth aspect. In any one of the first to fifth aspects, a method for producing A sixth aspect of the present invention provides a method for producing a colored pencil lead impregnated with an oil, and a seventh aspect of the present invention provides a method for producing a colored pencil lead in which the oil is an ink.

The details will be described below. The resin as the binder used in the present invention is classified into a resin for shaping the core and a resin for coating the surface of the fibrous material. The resin used to shape the core is a resin that is not eluted by the solvent used to remove the resin that has coated the surface of the fibrous material with a solvent when forming pores after molding into the core. The resin that coats the surface of the fibrous material is a resin that is incompatible with the resin that shapes the core during molding.The resin that shapes the core and the resin that coats the surface of the fibrous material are water-soluble resins. And water-insoluble resins, combinations of water-insoluble resins, and combinations of water-soluble resins.

Examples of the water-insoluble resin include polyvinyl chloride, polyvinylidene chloride, nitrified cotton, and cellulose acetate.
Cellulose, butyrate acetate, acrylic-styrene copolymer,
Examples of resins generally used, such as thermosetting resins and thermoplastic resins, such as acryl-butadiene styrene copolymer, polycarbonate, polyacetal, polyethylene, phenol resin, and benzoguanamine resin.

On the other hand, examples of the water-soluble resin include natural polymers such as corn starch and gum arabic, semisynthetic polymers such as dextrin, carboxymethylcellulose and ethylcellulose, polyethylene oxide resins, polyvinyl alcohol, polyvinylpyrrolidone and polyester polyol resins. Synthetic polymers such as polyether polyol resins and sodium polyphosphate, inorganic polymers such as water glass, and the like, but are processed into a core, because a resin that does not decompose or volatilize at the temperature when drying is preferable, Use of a resin having thermoplasticity is more preferred.

As the combination of the water-insoluble resins,
Utilizing the difference in solubility with various solvents including organic solvents, it is only necessary to consider a combination of resins in which one of the water-insoluble resins is eluted. Examples thereof include a thermoplastic resin having a low degree of polymerization and having a one-dimensional structure, such as polyvinyl chloride, polyvinylidene chloride, and polymethyl methacrylate. In addition, examples of the resin having low solubility include those having a crystalline structure and a high degree of polymerization, and resins having a three-dimensional structure, such as polyethylene, nylon, phenolic resin, and polyacrylonitrile. No.

As the combination of the water-soluble resins, a combination of resins having different solubility among the water-soluble resins may be considered in the same manner as the combination of the non-water-soluble resins described above. Although it is a resin, it contains a functional group having a non-polar bond in its molecular structure, so that it is a resin that dissolves in some organic solvents such as alcohol, acetone and trichlene, such as polyvinylpyrrolidone and polyethylene oxide. Can be

Next, the method of coating the surface of the fibrous material with the binder depends on the type of the fibrous material to be used. Once put, a wet method such as dissolving a binder to be coated in a solvent, immersing the fibrous material in the solvent, and drying and dipping the solution is preferred.

Even under dry conditions, for fibrous materials having a Mohs' hardness of 7 or more, such as silicon nitride fibers, silicon carbide fibers, and aluminum borate fibers, the resin is self-heated by a Hensyl mixer or the like, or is melted by a heat medium. It is also possible to coat with a Mohs hardness of 7
The following fibers tend to be easily broken at the time of dispersion and tend to lower the aspect ratio. Therefore, it is necessary to pay attention to the processing conditions such as the number of rotations, temperature, and time.

One of the water-soluble resin and the water-insoluble resin described above serves as a binder for the colored pencil core, and the other serves as a resin for covering the fibrous material and forming pores. The amount of the resin used to coat the fibrous material as the pore-forming material depends on the type and specific surface area of the fibrous material serving as the base material.
The amount used is preferably such that the strength of the binder for shaping the core is not impaired, and is preferably in the range of 2 to 6% by weight based on the weight of the fibrous material.

If the amount of the resin used as the pore-forming material is less than 2% by weight, the surface of the fibrous material cannot be uniformly coated, and sufficient pores may not be formed. Also, 6
When the amount exceeds the weight%, the surface of the fibrous material is sufficiently covered, but the excess resin segregates in the core body. The porosity becomes too large and the strength decreases as a result, and the writing line tends to be mottled and blurred. It can get worse.

The amount of the fibrous material coated with the binder as the pore-forming material is determined in consideration of satisfying each of the practical strength, color developing property, and writing taste aimed at by the present invention. , About 10 to 4 with respect to the total amount excluding the volatile solvent
The use of 0% by weight is preferred.

As other materials, talc, mica,
Plate-like crystalline materials such as boron nitride, calcium carbonate, graphite fluoride, and Nε-lauroyl lysine; potassium titanate fiber, titanium oxide fiber, magnesium sulfate hydrate fiber, silicon carbide fiber, silicon nitride fiber, boric acid Needle-like crystalline fibrous materials such as aluminum fibers, coloring materials,
Natural and synthetic dyes, inorganic and organic pigments can be used arbitrarily, and examples of the lubricant include various fatty acids such as metal stearic acid and amino acid stearic acid. In addition, if necessary, tricresyl phosphate, dimethyl phthalate, diallyl phthalate, dibutyl phthalate,
A plasticizer such as dioctyl phthalate, and various solvents such as methyl ethyl ketone, ethyl acetate, and water are appropriately added to the above-mentioned materials as compounding materials.
The mixture is dispersed and kneaded with the present roll or kneader, and when a solvent is used, the mixture is molded with an extruder or the like while adjusting the solvent content, and subjected to a drying treatment or the like to obtain a core.

Next, pores are formed by leaving the binder for shaping the core and removing the binder covering the fibrous material. The method of removing the binder covering the fibrous material is as follows. When a water-soluble resin is used as the binder, the core may be immersed in water or the like to elute the water-soluble resin as the pore-forming material. In this case, the water-insoluble resin as the pore-forming material may be immersed in an organic solvent or the like to elute. At this time, heating, pressurization and decompression may be performed. However, unlike a baked core, a raw wick (non-baked wick) is used. It is desirable to process under pressure. In order to elute the resin as the pore-forming material in a short time, ultrasonic waves and the like are particularly effective.

As described above, according to the present invention, the resin whose surface is coated with a solvent such as water or an organic solvent is eluted with the solvent after the core is formed. It is necessary to pay attention to the use of a resin whose solubility changes under heating, pressurization, or reduced pressure, as well as a combination of resins that are compatible with the solvent, since the strength is significantly reduced.

The pores of the color pencil core obtained as described above may be impregnated with an oily substance. As the oily substance, conventionally known silicone oils, mineral oils and machine oils can be used as long as they are easily impregnated into the pores. Oil, liquid paraffin, various ester compounds such as phthalic acid ester, α-olefin oligomer,
It is a natural or synthetic fat or oil such as palm oil, oleic acid, olive oil, or squalane, and can be used alone or in combination of several kinds of fats and oils at room temperature, either solid or liquid. or,
Water-based, oil-based, and alcohol-based conventionally known various inks can be used, and the color-forming effect can be obtained by using only the ink. However, when used in combination with the various oils and fats described above, the color-forming property and writing taste are further improved. A colored core can be provided.
However, when the core is impregnated with the oil and the ink, attention must be paid to the combination of the oil and the fat and the ink that dissolves the binder forming the core.

[0028]

According to the present invention, a color core for a mechanical pencil having a core diameter of 2 mm or less, using a fibrous material for at least a part of a body material, improving not only strength but also coloration and writing taste. The reason why a colored core is obtained is that, in the past, the point where the fibrous material was simply peeled off from the core in contact with the paper surface during writing was formed near the fibrous material. It is considered that the pores absorbed the stress during writing, and the stress propagated and passed through the pores into the core, whereby the self-disintegration of the core was enhanced and block-like wear occurred. Further, by impregnating the pores with an oily substance, a body material such as talc or mica further promotes a lubricating effect when a lubricant such as wax or stearic acid is worn, and a pigment is applied to the paper surface with a pigment. It is presumed that the colored body material particles may be worn uniformly.

[0029]

EXAMPLES <Example 1> A: Preparation of fibrous material coated with binder 2 parts by weight of polyvinyl alcohol (water-soluble resin) was dissolved in 100 parts by weight of water in a beaker, and magnesium sulfate aqueous solution was added thereto. Japanese fibrous material (Ube Materials Co., Ltd.)
Moss heidi) is immersed therein, and the water is evaporated while stirring with a drier to obtain a fibrous material (I) of magnesium sulfate hydrate coated with polyvinyl alcohol (water-soluble resin).

B. Manufacture of color core Nitrified cotton (water-insoluble resin) 20 parts by weight Magnesium sulfate hydrate fibrous material (I) coated with polyvinyl alcohol (water-soluble resin) 25 parts by weight Stearic acid 5 parts by weight Wax 5 parts by weight Nε -Lauroyl lysine 30 parts by weight Propylene carbonate 5 parts by weight Lake red pigment 10 parts by weight Methyl ethyl ketone (solvent) 100 parts by weight

After kneading the above-mentioned materials while adjusting the amount of the solvent with a three-roll mill, extruding them into a thin line, drying them at 80 ° C. for about 8 hours in a drier to remove the solvent, and removing the obtained core into water After ultrasonic cleaning at a frequency of 37 KHZ for about 40 minutes, a red core for a mechanical pencil having a nominal diameter of 0.9 was obtained.

<Example 2> In Example 1, the obtained core was impregnated with spindle oil at 40 ° C for about 20 minutes, and the oil was thoroughly removed with a centrifuge to obtain a red core.

<Examples 3 to 7> In Example 1, the amount of polyvinyl alcohol (water-soluble resin) used was 0.5, 1.0,
A fibrous material of magnesium sulfate hydrate changed to 3.0, 3.5, and 5.0 parts by weight was used, molded into a core, and subjected to the same impregnation treatment as in Example 2 to obtain a red core. Was.

<Example 8> In Example 2, red water-based ink was impregnated for about 20 minutes instead of spindle oil, and excess ink was removed with a centrifuge to obtain a red core.

<Comparative Example 1> In Example 1, except that no polyvinyl alcohol (water-soluble resin) was used and a fibrous material of magnesium sulfate hydrate not coated with polyvinyl alcohol was used. A red core was obtained in the same manner as described above.

<Example 9> C: Preparation of fibrous material coated with binder Polyester polyol resin (water-soluble resin and thermoplastic)
2 parts by weight were put in 100 parts by weight of methanol in a beaker, dissolved while heating at 60 ° C., and potassium titanate fibrous material (Tismo D, manufactured by Otsuka Chemical Co., Ltd.)
Is placed in a drier, and methanol is evaporated with stirring to obtain a potassium titanate fibrous material (II) coated with a water-soluble resin.

D: Process for producing color core Polyvinyl chloride (water-insoluble resin) 22 parts by weight Plasticizer 13 parts by weight Potassium titanate fibrous material (II) coated with polyester polyol resin (thermoplastic resin with water-soluble resin) 20 parts by weight Stearic acid 2 parts by weight Stabilizer 2 parts by weight Talc 31 parts by weight Copper phthalocyanine blue 10 parts by weight Methyl ethyl ketone (solvent) 50 parts by weight

After kneading the above materials with a hot roll, they are pelletized and extruded into a fine wire by a screw extruder.
After drying for about 8 hours, the core obtained by removing the plasticizer is immersed in water, ultrasonically washed at a frequency of 37 KHZ for about 40 minutes, and a blue core for a mechanical pencil with a nominal diameter of 0.9 is obtained. Obtained.

Example 10 The core obtained in Example 9 was impregnated in spindle oil at 60 ° C. for about 20 minutes, and the oil was thoroughly removed with a centrifuge to obtain a blue core.

<Examples 11 to 15> In Example 9, the amounts of the polyester polyol resins used were 0.5, 1.0,
Using a fibrous material of potassium titanate changed to 3.0, 3.5, and 5.0 parts by weight, and molded into a core, the same impregnation treatment as in Example 10 was performed to obtain a blue core.

Example 16 In Example 10, a blue oil-based ink was impregnated for 20 minutes instead of the spindle oil, and the ink was removed with a centrifuge to obtain a blue core.

Comparative Example 2 The procedure of Example 9 was repeated, except that the polyester polyol resin was not used, and a potassium titanate fibrous material not coated with the polyester polyol resin was used. A core was obtained.

Example 17 E: Preparation of fibrous material coated with binder 2 parts by weight of nitrified cotton (water-insoluble resin) was placed in a beaker 1
The mixture was dissolved in 00 parts by weight of ethyl acetate, dissolved therein, and 50 parts by weight of a titanium oxide fibrous material (manufactured by Ishihara Sangyo Co., Ltd., FTL200) was immersed therein. A titanium oxide fibrous material (III) coated with a water-insoluble resin is obtained.

F: Production method of color core Carboxymethyl cellulose (water-soluble resin) 14 parts by weight Titanium oxide fibrous material (III) coated with nitrified cotton (water-insoluble resin) 19 parts by weight Aspartic acid ester 4 parts by weight Talc 50 parts by weight Parts wax 5 parts by weight lake red pigment 8 parts by weight water 100 parts by weight

The above materials were dispersed in a kneader, kneaded with three rolls, formed by an extruder, dried at 50 ° C. for about 70 hours,
The obtained core was immersed in methyl ethyl ketone and 37 KH
After ultrasonic cleaning at a frequency of Z for about 10 minutes, a red core having a nominal diameter of 2 mm was obtained.

<Example 18> In Example 17, the obtained core was immersed in spindle oil at 40 ° C for about 20 minutes, and the oil was removed with a centrifuge to obtain a red core. .

<Examples 19 to 23> In Example 17, the amounts of nitrified cotton used were 0.5, 1.0, 3.0, 3.5,
Using a titanium oxide fibrous substance changed to 5.0 parts by weight, a core was formed, and then impregnated in the same manner as in Example 18 to obtain a red core.

<Example 24> In Example 18, a red aqueous ink was impregnated for about 20 minutes instead of the spindle oil, and the ink was removed by a centrifugal separator to obtain a red core.

<Comparative Example 3> A blue core was obtained in the same manner as in Example 17, except that nitrified cotton was not used and a titanium oxide fibrous material not coated with nitrified cotton was used. Was.

<Example 25> G: Preparation of fibrous material coated with binder 2 parts by weight of cellulose acetate (water-insoluble resin) was dissolved in 100 parts by weight of methyl ethyl ketone in a beaker, and oxidized therein. Titanium fibrous material (manufactured by Ishihara Sangyo Co., Ltd.
FTL200) is immersed in 50 parts by weight, placed in a drier and stirred to evaporate methyl ethyl ketone to obtain a titanium oxide fibrous material (IV) coated with a water-insoluble resin.

H: Method for producing color core Polyethylene resin (water-insoluble resin) 20 parts by weight Titanium oxide fibrous material (IV) coated with cellulose acetate (water-insoluble resin) 15 parts by weight Aspartic acid ester 5 parts by weight Talc 35 Parts by weight wax 15 parts by weight lake red pigment 10 parts by weight methyl ethyl ketone 50 parts by weight

The above-mentioned material was dispersed and granulated using a Hensyl mixer, pelletized, formed into a fine wire shape by a continuous extruder, and the obtained core was immersed in methyl ethyl ketone.
After cleaning at 37KHZ frequency for about 30 minutes, nominal diameter 2m
m red core was obtained.

<Example 26> The core obtained in Example 25 was immersed in spindle oil at 60 ° C for about 20 minutes, and the oil was thoroughly removed with a centrifuge to obtain a red core.

<Examples 27 to 31> In Example 25, the amounts of cellulose acetate used were 0.5, 1.0, 3.0 and 3.0, respectively.
Using a titanium oxide fibrous material changed to 5, 5.0 parts by weight, the core was molded, and then impregnated in the same manner as in Example 26 to obtain a red core.

<Example 32> In Example 26, a red aqueous ink was impregnated for about 20 minutes instead of the spindle oil, and the ink was cut off with a centrifuge to obtain a red core.

<Comparative Example 4> A red core was obtained in the same manner as in Example 25 except that cellulose acetate was not used and a titanium oxide fibrous material not coated with cellulose acetate was used. .

<Example 33> I: Preparation of fibrous material coated with binder 2 parts by weight of polyvinylpyrrolidone (water-soluble resin) was dissolved in 100 parts by weight of water in a beaker, and potassium titanate was added therein. 50 parts by weight of a fibrous material (manufactured by Otsuka Chemical Co., Ltd., Tismo D) is immersed, dipped in a drier, and water is evaporated while stirring to obtain a potassium titanate fibrous material (V) coated with a water-soluble resin. obtain.

J: Preparation of color core Carboxymethylcellulose (water-soluble resin) 14 parts by weight Potassium titanate fibrous material (V) coated with polyvinylpyrrolidone (water-soluble resin) 15 parts by weight Aspartic ester 5 parts by weight Talc 48 parts by weight Parts wax 10 parts by weight lake red pigment 8 parts by weight water 100 parts by weight

The above materials were dispersed in a kneader, kneaded with three rolls, formed by an extruder, dried at 50 ° C. for about 70 hours, and the obtained core was immersed in methyl ethyl ketone.
Nominal diameter 2m after ultrasonic cleaning for about 10 minutes at KHZ frequency
m red core was obtained.

Example 34 The core obtained in Example 33 was immersed in spindle oil at 40 ° C. for about 20 minutes, and the oil was thoroughly removed with a centrifuge to obtain a red core.

<Examples 35 to 39> In Example 33, the amounts of polyvinylpyrrolidone used were 0.5, 1.0, and 3.
Using a potassium titanate fibrous material changed to 0, 3.5, or 5.0 parts by weight, the core was molded, and then impregnated in the same manner as in Example 34 to obtain a red core.

<Example 40> In Example 34, instead of spindle oil, red oil-based ink was impregnated for about 20 minutes, and the ink was removed with a centrifugal separator to obtain a red core.

Comparative Example 5 A red core was prepared in the same manner as in Example 33 except that polyvinyl pyrrolidone was not used and a potassium titanate fibrous material not coated with polyvinyl pyrrolidone was used. Obtained.

The bending strength of the color core obtained in each of the above examples and the density as a substitute property of the color developing property were measured according to the measuring method of JIS S6005. The smaller the value, the better the writing quality. Tables 1 to 4 show the results of the above measurements.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

[0068]

[Table 4]

[0069]

As shown in the above table, according to the present invention, in a color core using a fibrous material as a part of the constitutional material, the writing taste and the coloring property are sacrificed as before to obtain strength. This makes it possible to provide a colored pencil lead satisfying each characteristic without performing the above steps.

Claims (7)

[Claims] 1. A binder for shaping a core, a filler, a coloring material, and a lubricant, and at least a fibrous material is used as a part of the filler, and these are kneaded and molded. In a non-fired type color pencil lead that is appropriately dried, using the fibrous material, the surface of which is coated in advance with a binder that forms the core and a binder that is incompatible during molding,
A method for producing a colored pencil lead, in which, after drying, the binder covering the fibrous material is removed to form pores. 2. The colored pencil lead according to claim 1, wherein the binder for shaping the core and the binder incompatible with the binder at the time of molding are a combination of a water-soluble resin and a water-insoluble resin. Method. 3. The method for producing a colored pencil lead according to claim 2, wherein the water-soluble resin is a resin having thermoplasticity. 4. The method for producing a color pencil lead according to claim 1, wherein the binder forming the core and the binder incompatible with the binder at the time of molding are a combination of water-insoluble resins. 5. The method for producing a colored pencil lead according to claim 1, wherein the binder for shaping the core and the binder incompatible with the binder at the time of molding are a combination of water-soluble resins. 6. The method for producing a colored pencil lead according to claim 1, wherein an oily substance is impregnated in the pores. 7. The method according to claim 6, wherein the oily substance is an ink.