JP7365854B2 - colored pencil lead - Google Patents

Description

The present invention relates to a colored pencil lead. More specifically, the present invention relates to a colored pencil lead that has excellent color development and erasability, has a smooth writing feel, and has high physical strength.

Traditionally, colored pencil leads used in mechanical pencils and the like are mainly composed of a dielectric material such as boron nitride and a binder material such as clay, and are made by extrusion molding a kneaded material containing an organic polymer compound as necessary. A white porous core obtained by firing at a high temperature and having the pores impregnated with ink containing a coloring agent is used. In order to enhance the coloring properties of such colored pencil leads, it is conceivable to increase the amount of ink or colorant contained in the colored pencil leads.

However, if the porosity of the porous core is increased in order to increase the amount of ink to be impregnated, the strength of the core tends to decrease. Furthermore, when the concentration of the colorant in the ink is increased, the colorant may precipitate due to solvent volatilization, resulting in a change in the color tone of handwriting. Furthermore, the evaporation of the solvent tended to change the writing feel when writing.

Furthermore, depending on the type of dye or solvent contained in the ink, the material or member that holds the colored pencil lead may be denatured. Specifically, when oleic acid or the like is used as a solvent, parts such as mechanical pencils and holders that hold colored pencil leads may become corroded over time.

Japanese Unexamined Patent Publication No. 51-63744 Japanese Unexamined Patent Publication No. 61-23667 Utility Model Publication No. 61-142835 Japanese Patent Application Publication No. 07-041723

The present invention provides a colored pencil lead that has excellent writing feel and color development of handwriting during writing, and can maintain the writing feel and color development at a high level even after storage over time.

The colored pencil lead according to the present invention is
a porous core comprising a physical material and an inorganic binding material;
colored ink filled in the pores of the porous core;
It contains;
The colored ink is characterized in that it contains a colorant and a plasticizer selected from the group consisting of carboxylic acid esters of polyalkylene glycol and carboxylic acid esters of alcohol.

Furthermore, the method for producing colored pencil lead according to the present invention includes:
(a) a kneading step of preparing a mixture by kneading the extender and the inorganic binder;
(b) an extrusion step of extruding the mixture to create a linear molded product;
(c) a firing step of firing the linear molded product to create a porous core, and (d) adding a coloring agent, a carboxylic acid ester of polyalkylene glycol, and a carboxylic acid of alcohol to the porous core. an impregnating step of contacting and impregnating a colored ink containing a plasticizer selected from the group consisting of esters;
It is characterized by comprising.

The colored pencil lead according to the present invention has sufficient strength, excellent writing taste and color development. Furthermore, the colored pencil lead according to the present invention has excellent stability over time and can maintain excellent writing taste and color development even after time. At the same time, the handwriting formed by the colored pencil lead also has excellent stability over time.

<Colored pencil lead>
The colored pencil lead according to the present invention includes a porous core and a colored ink filled in the pores of the porous core. The following is an explanation of their configuration:

The porous core used in the colored pencil lead of the present invention contains an extender and an inorganic binder as main components. Extending materials include white materials such as titanium oxide, mica, talc, boron nitride, alumina, and calcium carbonate, and colored materials such as molybdenum disulfide, tungsten disulfide, and graphite. It is desirable that the colored pencil lead according to the present invention forms vivid handwriting. Furthermore, when a fluorescent coloring agent is used as a coloring agent to form fluorescent handwriting, it is preferable to use a coloring agent that does not inhibit color development. Therefore, in order to form handwriting with high brightness, it is preferable to use a white body material. In particular, it is preferable to use boron nitride because the extender does not inhibit color development and the strength of the colored pencil lead increases.

Examples of the inorganic binder include clays such as kaolinites, hallosites, montmorillonites, sericites, and bentonites, ceramics, zeolites, diatomaceous earth, activated clay, silica, and aluminum phosphate, These can be used alone or in combination.

The mixing ratio of the bulking material and the inorganic binder, which are the main components of the porous core, is not particularly limited, but it is preferably 9:1 to 7:3 in terms of mass ratio.

In the present invention, the porous core includes an extender and an inorganic binder. Generally, a pencil lead is manufactured by molding a mixture of an extender and an inorganic binder and then firing it, and the same method can be applied to the present invention. That is, it can be manufactured by firing a mixture of an extender and an inorganic binder (details will be described later).

In addition, by compressing a mixture containing a structural material, an inorganic binder, an inorganic substance, a water-soluble resin, etc. under high pressure, and then immersing it in water, a solvent, etc., to remove the inorganic substances, water-soluble resin, etc. It is also possible to produce porous cores.

Furthermore, the porosity of the porous core used in the present invention is not particularly limited, but is preferably in the range of 5 to 40%, more preferably in the range of 10 to 30%. If it is less than 5%, the amount of colored ink existing in the pores will be small, resulting in poor color development or a tendency to cause some resistance when brushing. If it is more than 40%, the strength of the resulting porous core will decrease. tends to decrease and become more likely to break. A content in the range of 5 to 40% is preferable because color development is good, writing is smooth, and the strength of the colored pencil lead can be maintained.

The porosity of the porous core used in the present invention can be measured by the following method with reference to JIS R1634 (1998). First, the dry mass (W1) of the porous core is measured. Next, the porous core is immersed in a liquid with good permeability (for example, benzyl alcohol) to absorb the liquid into the pores of the porous core until the liquid is saturated, and then the mass in the liquid (W2) is measured. Furthermore, the porous core is taken out of the liquid, and after removing the liquid adhering to its surface, the saturated liquid mass (W3) is measured. Using these measured values, the porosity is determined by the following formula (1).

Porosity = (W3-W1)/(W3-W2)×100 (1)

In the colored pencil lead according to the present invention, the pores of the above-mentioned porous core are filled with colored ink. This colored ink contains a colorant and a plasticizer as main components.

As the colorant, dyes or pigments can be used. Moreover, a colored pigment obtained by dyeing a resin with a dye can also be used. In general, when a dye is made into a solution, it easily penetrates into a porous core, which facilitates the manufacture of the pencil lead according to the present invention.

Dyes that can be used in the present invention are not particularly limited, and include general dyes and fluorescent dyes.

Examples of general dyes include oil-soluble dyes, acidic dyes, basic dyes, and metal-containing dyes. Further, salt-forming dyes of these dyes include salt-forming dyes of acidic dyes and basic dyes, salt-forming dyes of basic dyes and organic acids, salt-forming dyes of acidic dyes and organic amines, and the like. More specifically, Varifast Black 1802, Varifast Black 1805, Varifast Black 1807, Varifast Violet 1701, Varifast Violet 1704, Varifast Violet 1705, Varifast Blue 1601, Varifast Blue 1605, Varifast Blue 1613. , Varifast Blue 1621, Varifast Blue 1631, Varifast Red 1320, Varifast Red 1355, Varifast Red 1360, Varifast Yellow 1101, Varifast Yellow 1151, Nigrosine Base EXBP, Nigrosine Base EX, BASE OF BASIC DYES ROB- B, BASE OF BASIC DYES RO6G-B, BASE OF BASIC DYES VPB-B, BASE OF BASIC DYES VB-B, BASE OF BASIC DYES MVB-3 (Orient Chemical Industry Co., Ltd.), Eisenspiron Black GMH-Special, crampons Spiron Violet CRH, Eisenspiron Blue GNH, Eisenspiron Blue 2BNH, Eisenspiron Blue C-RH, Eisenspiron Red C-GH, Eisenspiron Red C-BH, Eisenspiron Yellow C-GNH, Eisenspiron Yellow C-2GH,S. P. T. Blue 111, S. P. T. Blue GLSH-Special, S. P. T. Red 533, S. P. T. Orange 6, S. B. N. Violet 510, S. B. N. Yellow 530, S. R. Examples include C-BH (Hodogaya Chemical Industry Co., Ltd.).

Examples of fluorescent dyes include Basic Yellow 1, 40, Basic Red 1, 1:1, 13, Basic Violet 1, 7, 10, 11:1, Basic Orange 22, Basic Blue 7, and Basic. Green 1, Acid Yellow 3, Acid 7, Acid Red 52, 77, 87, 92, Acid Blue 9, Disperse Yellow 121, 82, 83, Disperse Orange 11, Disperse Red 58, Disperse Blue 7, Direct Yellow 85, Direct Orange 8, Direct Red 9, Direct Blue 22, Direct Green 6, Solvent Yellow 44, Solvent Red 49, Solvent Blue 5, and Solvent Green 7.

These dyes may be used alone or in combination of two or more in order to adjust the color of handwriting within a range that does not affect the performance of the colored pencil lead. Furthermore, other dyes may be used in combination with these dyes.

Moreover, any pigment can also be used as the colorant. Further, ultrafine pigments, processed pigments, etc. can also be used.

Moreover, a colored pigment obtained by dyeing a resin with a dye can also be used. As the resin, any resin such as acrylic resin, styrene-acrylonitrile resin, styrene resin, nitrogen-containing resin, polyethylene resin, polypropylene resin, etc. can be used. Dyes to be combined with these resins can be selected from those listed above.

Considering the solubility of these resins in plasticizers, dispersibility and dispersion stability, and dyeability with dyes, it is preferable to use nitrogen-containing resins and styrene-acrylonitrile resins, and nitrogen-containing resins are preferred. More preferred. Regarding nitrogen-containing resins, melamine resins, polyamide resins, urethane resins, urea resins, benzoquanamine resins, etc. are preferably used, and from the viewpoint of dissolution stability with plasticizers, melamine resins and polyamide resins are preferable, and melamine resins are more preferable. .

Examples of color pigments include the NKS-1000 series, MPI-500 series (manufactured by Nippon Fluoro Chemical Co., Ltd.), the FNP series, and the FM series (manufactured by Shinroihi Co., Ltd.).

These coloring pigments may be used alone or in combination of two or more in order to adjust the color of handwriting within a range that does not affect the performance of the colored pencil lead. Furthermore, dyes may be used in combination with these colored pigments.

Pigmented inks also contain plasticizers. This plasticizer functions as a solvent or a dispersion medium. Generally, dyes are dissolved in plasticizers, and pigments are dispersed in plasticizers.

The plasticizers used in the present invention include (i) carboxylic acid ester of polyalkylene glycol (hereinafter sometimes referred to as ester (i)) and (ii) carboxylic acid ester of alcohol (hereinafter referred to as ester (ii)). selected from the group consisting of

(i) Carboxylic acid ester of polyalkylene glycol The polyalkylene glycol constituting the ester (i) preferably has 2 to 4 carbon atoms in the alkylene oxide unit. Specific examples include homopolymers or copolymers containing ethylene oxide, propylene oxide, and butylene oxide as units. These alkylene oxides generally have a linear structure, but may have a branched structure. Among these, polyethylene glycol, polypropylene glycol, and poly(ethylene oxide/propylene oxide) copolymer are preferred because they are easily available.

Further, the carboxylic acid constituting the ester (i) may be a monocarboxylic acid or a polycarboxylic acid, and may be an aliphatic carboxylic acid or an aromatic carboxylic acid. Among these carboxylic acids, carboxylic acids having 3 to 10 carbon atoms are preferred. Specific examples include propionic acid, butanoic acid, isobutanoic acid, n-pentanoic acid, 2-ethylbutyric acid, 2-ethylhexylic acid, decanoic acid, and the like.

Polyalkylene glycol has a plurality of hydroxyl groups at its ends, and the hydroxyl groups react with the carboxyl group of a carboxylic acid to form an ester. Generally, all hydroxyl groups of polyalkylene glycol react with carboxyl groups, but some hydroxyl groups may remain unreacted.

(ii) Carboxylic acid ester of alcohol The alcohol constituting the ester (ii) may be a monoalcohol or a polyol, but an alcohol having 2 to 14 carbon atoms is preferable. The hydrocarbon group constituting the alcohol may be saturated or unsaturated, and may contain an oxy group -O- between carbon atoms of the hydrocarbon chain. Specifically, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, n-hexyl alcohol, cyclohexyl alcohol, n-decyl alcohol, benzyl alcohol, ethoxyethyl alcohol, butoxyethyl alcohol, dibutoxyethoxyethyl alcohol. Examples include.

The carboxylic acid constituting the ester (ii) may be an aliphatic carboxylic acid or an aromatic carboxylic acid. The aliphatic carboxylic acid preferably has 3 to 10 carbon atoms. Further, the carboxylic acid is preferably a polycarboxylic acid having a plurality of carboxyl groups. Specific examples include malonic acid, fumaric acid, citric acid, acetylcitric acid, adipic acid, azelaic acid, and sebacic acid. The aromatic polycarboxylic acid preferably has 8 to 14 carbon atoms. Specific examples include phthalic acid, terephthalic acid, and trimellitic acid.

More specifically, (a) aliphatic polycarboxylic acid esters include diisodecyl adipate, di-n-octyl adipate, di-2-ethylhexyl azelaate, dibutyl sebacate, di-2-ethylhexyl sebacate, Triethyl citrate, acetyl tributyl citrate, etc. (b) Aromatic polycarboxylic acid esters include dimethyl phthalate, diethyl phthalate, dioctyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, trimethyl trimellitate, trimellitate, etc. Examples include triethyl acid, tripropyl trimellitate, tributyl trimellitate, trihexyl trimellitate, tri-n-octyl trimellitate, and the like.

Esters that can be used as plasticizers in the present invention are generally commercially available, and examples of ester (i) include Adekasizer RS-1000, RS-735, and RS-700 (all trade names, ADEKA Co., Ltd.). Examples of the ester (ii) include ADEKASIZER C-8, C-880, C-79, C810, C-9N, and C-10 (all trade names, manufactured by ADEKA Co., Ltd.). Further, among the esters (ii), examples of alcohols containing an oxy group include ADEKASIZER RS-107 (dibutoxyethoxyethyl adipate) (trade name, manufactured by ADEKA Co., Ltd.).

In the present invention, the above-mentioned esters (i) and (ii) can be used as the plasticizer, but among these, esters (i) and esters (ii) in which the alcohol contains an oxy group are Colored inks tend to have excellent solubility or stability. This is considered to be due to the high compatibility between the oxy group contained in the ester and the dye.

When using ester (i) and ester (ii) as plasticizers, from the viewpoint of solubility and dispersibility of the colorant and storage stability of colored pencil leads, it is preferable that the mass average molecular weight is 3,000 or less, and 1, 000 or less is more preferable.

Preferably, the plasticizer used in the present invention exhibits specific solubility properties. Specifically, it is preferable that the SP value is 8.0 or more and 11 or less. Here, the SP value is calculated as a mass-based weighted average of the SP values of each block constituting the plasticizer. Furthermore, when the plasticizer is a mixture of multiple types of compounds, the weighted average value of the SP values of each compound on a mass basis is taken as the SP value of the plasticizer.

In the present invention, the plasticizer is preferably one that does not easily volatilize at room temperature. By using such a plasticizer, the stability of colored pencil leads over time can be maintained at a high level. Specifically, the plasticizer is preferably a liquid that does not volatilize at temperatures below 250°C. Further, the plasticizer preferably has a low viscosity in order to facilitate impregnation into the pores of the porous core. Specifically, the viscosity of the plasticizer at 25° C. is preferably 1,000 mPa·s or less, more preferably 500 mPa·s or less, and even more preferably 100 mPa·s or less. The viscosity here is measured by a method based on JIS-K-2283.

The appropriate concentration of the colorant in the colored ink varies depending on the type of colorant, but is preferably 5 to 60% by mass, more preferably 20 to 50% by mass, and 30 to 50% by mass. It is particularly preferable that Further, the content of the colored ink relative to the total mass of the colored pencil lead varies depending on the type thereof, but is preferably 15 to 40% by mass, more preferably 20 to 30% by mass. If it is less than this range, the content of the colorant will be low and the color development will tend to be poor, and if it is more than this range, the color development will not tend to improve in accordance with the amount of colorant added. There is a risk that the stability of the solution or dispersion over time may deteriorate, such as the colorant precipitating over time.

The colored pencil lead according to the present invention may contain various additives within a range that does not affect its performance. Specific additives include surfactants, preservatives, fungicides, resins, and the like. These additives may be blended into the colored ink or the porous core.

Although the shape of the colored pencil lead according to the present invention is not particularly limited, it is generally a linear body having a circular cross section. For example, as a colored pencil lead for a mechanical pencil, the cross-sectional diameter is preferably 0.2 to 2.0 mm, and preferably 0.3 to 0.7 mm. Further, the length is preferably 30 to 100 mm, more preferably 40 to 70 mm. When applied to general colored pencils held on a support such as wood, the cross-sectional diameter is preferably 0.5 to 3.0 mm, more preferably 0.8 to 2.0 mm. . In the manufacturing process of general colored pencils, a long colored pencil lead is often sandwiched between wood or the like and then cut, so the length is not limited, but is generally 1,000 mm or less.

The colored pencil lead according to the present invention can achieve high physical strength by using a porous lead produced by firing. The bending strength of the colored pencil lead according to the present invention is preferably 120 MPa or more. More preferably, it is 180 MPa or more. Here, the bending strength can be measured by the method specified in JIS S 6005:2007.

<Production method of colored pencil lead>
The method for producing colored pencil lead according to the present invention is not particularly limited. however,
(a) a kneading step of preparing a mixture by kneading the extender and the inorganic binder;
(b) an extrusion step of extruding the mixture to create a linear molded product;
(c) a firing step of firing the linear molded product to create a porous core, and (d) adding a coloring agent, a carboxylic acid ester of polyalkylene glycol, and a carboxylic acid of alcohol to the porous core. an impregnating step of contacting and impregnating a colored ink containing a plasticizer selected from the group consisting of esters;
Preferably, it is produced by a method comprising: This method will be explained below.

(a) Kneading process First, an extender and an inorganic binder are kneaded to prepare a mixture. This mixture is the main component of the porous core. During mixing, organic solvents, plasticizers, and the like may be added as necessary. The plasticizer used here is to give fluidity to the raw material mixture and make the mixture uniform, and it is almost completely removed during the firing process, and is independent of the plasticizer used in the colored ink. This is what I did.

(b) extrusion step;
Subsequently, the formed mixture is extruded to create a linear molded article. Since the colored pencil lead according to the present invention is generally preferably formed into a linear body having a circular cross-sectional shape, it is made into a linear molded product by extrusion molding.

(c) Firing step After drying the obtained linear molded product as necessary, it is fired to create a porous core. By firing, the organic solvent contained in the mixture is removed, and the bulk material and the inorganic binder are sintered to form a porous core. The firing conditions are not particularly limited as long as the materials are sintered to form a porous core, but the maximum temperature can be, for example, 650 to 1000°C. Furthermore, in order to avoid sudden temperature changes, the temperature during firing can be raised continuously or in stages. The temperature increase rate in such a case can be, for example, 10 to 100° C./hr. Further, it is also preferable that after raising the temperature to a set temperature, baking is performed at a constant temperature for a certain period of time, for example, about 0.5 to 2 hours. Furthermore, these conditions can be arbitrarily combined depending on the purpose. For example, in an oxygen atmosphere, the temperature is raised from room temperature to 650 °C at a rate of 10 °C/hr, and then the temperature is maintained at 650 °C for 1 hour. Conditions such as firing at 1000° C. for 1 hour can be adopted.

(d) Impregnation step After cooling the formed porous core as necessary, the porous core is brought into contact with colored ink. In this step, the colored ink penetrates into the pores present in the porous core. As the impregnation method, normal pressure impregnation, reduced pressure, or pressure impregnation can be used.

If necessary, washing or the like may be further performed to obtain a colored pencil lead according to the present invention.

Examples of the present invention will be described below, but the present invention is not limited thereto.

[Examples 1 to 4, Comparative Example 1]
[Kneading process, extrusion process, and baking process]
Boron nitride: 45 parts by mass Silica: 45 parts by mass Polyvinyl alcohol: 10 parts by mass Water: 100 parts by mass The above mixture is heated and kneaded with a kneader and three rolls while evaporating water, and the obtained kneaded product is extruded to a predetermined diameter. Molding was performed to obtain a linear molded product. This linear molded product was heated to 600°C at a heating rate of 10°C/hr in an argon gas atmosphere and held for 5 hours, and then heated at 100°C/hr in an oxygen atmosphere to 900°C for 1 hour. A porous core having a porosity of 25% was obtained by firing.

The colorant and plasticizer shown in Table 1 were mixed and stirred at 60° C. until uniformly mixed to obtain a colored ink.

The porous core obtained in the firing process is immersed in each colored ink at a temperature of 60°C, held for 6 hours, and the colored ink remaining on the surface is wiped off to form colored pencil leads. I got it.

表中、
ピンク色蛍光顔料：ＭＰＩ－５０７Ｃ（商品名、日本蛍光化学株式会社製、メラミン・パラトルエンスルホンアミド・ホルマリン重縮合物（メラミン樹脂）と、ベーシックバイオレット１１：１（蛍光染料）と、ベーシックレッド １：１（蛍光染料）との混合物からなる蛍光顔料）
イエロー色蛍光顔料：ＭＰＩ－５０５Ｃ（商品名、日本蛍光化学株式会社製、メラミン・パラトルエンスルホンアミド・ホルマリン重縮合物（メラミン樹脂）と、ベーシックイエロー４０（蛍光染料）との混合物からなる蛍光顔料）
オレンジ色蛍光顔料：ＭＰＩ－５０４Ｃ（商品名、日本蛍光化学株式会社製、メラミン・パラトルエンスルホンアミド・ホルマリン重縮合物（メラミン樹脂）と、ベーシックイエロー４０（蛍光染料）と、ベーシックバイオレット１１：１（蛍光染料）と、ベーシックレッド １：１（蛍光染料）との混合物からなる蛍光顔料）

In the table,
Pink fluorescent pigment: MPI-507C (trade name, manufactured by Nippon Fluorescent Chemical Co., Ltd., melamine/paratoluenesulfonamide/formalin polycondensate (melamine resin), Basic Violet 11:1 (fluorescent dye), Basic Red 1 :1 (fluorescent pigment consisting of a mixture with fluorescent dye))
Yellow fluorescent pigment: MPI-505C (trade name, manufactured by Nippon Fluorescent Chemical Co., Ltd., a fluorescent pigment consisting of a mixture of melamine/paratoluenesulfonamide/formalin polycondensate (melamine resin) and Basic Yellow 40 (fluorescent dye) )
Orange fluorescent pigment: MPI-504C (trade name, manufactured by Nippon Fluorescent Chemical Co., Ltd., melamine/paratoluenesulfonamide/formalin polycondensate (melamine resin), Basic Yellow 40 (fluorescent dye), Basic Violet 11:1 (fluorescent pigment) consisting of a mixture of (fluorescent dye) and Basic Red (fluorescent dye) 1:1)

[evaluation]
The performance of the obtained colored pencil lead was evaluated by the following method.

[Evaluation method of initial color development (color development 1)]
Made of high-quality paper (equivalent to writing paper A specified in the old JIS P3201, made from 100% chemical pulp, weighing range 40 to 157 g/m2, whiteness 75.0% or more) using colored pencil lead. The state of color development at that time was visually evaluated.
A: Very good coloring, and the fluorescent color is clearly visible.
B: The handwriting is thin and the color development is slightly inferior, but the fluorescent color is visible.
C: The handwriting is thin, the color development is poor, and the fluorescent color is difficult to see.

[Evaluation method of initial writing taste (writing taste 1)]
Writing was performed on the above-mentioned high-quality paper using a colored pencil lead, and the writing feeling at that time was evaluated by a sensory test.
A: Can be written very smoothly.
B: Can be written smoothly.
C: The brush feel is slightly rough and heavy.

[Evaluation method of color development after time (color development 2)]
After production, the fired colored pencil lead was left in an environment of 25° C. for 4 weeks to write on the above-mentioned high-quality paper, and the state of color development at that time was visually evaluated.
A: Very good coloring, and the fluorescent color is clearly visible.
B: The handwriting is thin and the color development is slightly inferior, but the fluorescent color is visible.
C: The handwriting is thin, the color development is poor, and the fluorescent color is difficult to see.

[Method for evaluating writing taste after aging (writing taste 2)]
After production, the fired colored pencil lead was left in an environment of 25° C. for 4 weeks to write on the above-mentioned high-quality paper, and the writing feel at that time was evaluated by a sensory test.
A: Can be written very smoothly.
B: Can be written smoothly.
C: The brush feel is slightly rough and heavy.

The results obtained are as shown in Table 2.

In addition, when the colored pencil leads of Examples 1 to 4 were used in mechanical pencils that had a brass chuck and that fed out the pencil lead by moving the chuck forward, the colored pencil lead was held in the chuck in a 50°C environment. The chuck did not corrode even after being left for eight weeks.

Claims (6)

a porous core comprising a physical material and an inorganic binding material;
colored ink filled in the pores of the porous core;
It contains;
The colored ink is
Colored pigments dyed resin with dyes ,
A colored pencil lead comprising a plasticizer which is an ester of a polyalkylene glycol consisting of an alkylene oxide unit having 2 to 4 carbon atoms and a carboxylic acid having 3 to 10 carbon atoms. The colored pencil lead according to claim 1 , wherein the extender material is selected from the group consisting of titanium oxide, mica, talc, boron nitride, alumina, and calcium carbonate. The colored pencil lead according to claim 1 or 2 , wherein the inorganic binder is selected from the group consisting of clays, ceramics, zeolites, diatomaceous earth, activated clay, silica, and aluminum phosphate. The colored pencil lead according to any one of claims 1 to 3 , wherein the porous core has a porosity of 5 to 40%. The colored pencil lead according to any one of claims 1 to 4 , wherein the porous core is a fired core. (a) a kneading step of preparing a mixture by kneading the extender and the inorganic binder;
(b) an extrusion step of extruding the mixture to create a linear molded product;
(c) a firing step of firing the linear molded product to create a porous core; and (d) adding a colored pigment to the porous core with a resin dye and a carbon number of 2 to 4. an impregnation step of contacting and impregnating a colored ink comprising a polyalkylene glycol consisting of alkylene oxide units and a plasticizer which is an ester of a carboxylic acid having 3 to 10 carbon atoms;
A method for producing a colored pencil lead, the method comprising: