CN114466751A

CN114466751A - Colour burnt pencil lead

Info

Publication number: CN114466751A
Application number: CN202080069432.1A
Authority: CN
Inventors: 神林宏信; 乾太郎
Original assignee: Pilot Corp
Current assignee: Pilot Corp
Priority date: 2019-09-30
Filing date: 2020-09-25
Publication date: 2022-05-10
Anticipated expiration: 2040-09-25
Also published as: JPWO2021065724A1; CN114466751B; WO2021065724A1; TW202120633A

Abstract

The invention provides a colored pencil lead which is excellent in handwriting erasure, smooth in writing feeling and excellent in physical strength. The colored pencil lead of the present invention comprises a porous core and a nonvolatile liquid filled in pores of the porous core, wherein the porous core comprises a host material, an inorganic binder and a solid colorant.

Description

Colour burnt pencil lead

Technical Field

The invention relates to a colored pencil lead. More particularly, the present invention relates to a colored pencil lead having excellent color developability and erasability, smooth writing feeling, and high physical strength.

Background

Conventionally, a colored pencil lead used for a mechanical pencil or the like is a pencil lead which is formed by using a main component such as boron nitride and a binder such as clay as main components, extruding a kneaded product containing an organic polymer compound or the like as necessary, and then impregnating an ink containing a dye into pores of a white porous base material obtained by firing at a high temperature. When writing on paper using such a colored pencil lead, the ink impregnated into the pores penetrates into the fibers of the paper, whereby coloring components such as dyes penetrate into the paper, and therefore, when erasing the writing written on the colored pencil lead with an eraser, the erasing property of the writing may be lowered.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 51-63744

Patent document 2: japanese laid-open patent publication No. 61-23667

Patent document 3: japanese Kokai publication Sho-61-142835

Patent document 4: japanese laid-open patent publication No. H07-041723

Disclosure of Invention

Problems to be solved by the invention

The invention provides a colored pencil lead which is excellent in erasing property of handwriting, smooth in writing feeling and high in physical strength.

Means for solving the problems

The invention provides a colored pencil lead, which is characterized by comprising:

a porous core, and

a nonvolatile liquid filled in the pores of the porous core,

the porous core comprises a host material, an inorganic binding material, and a solid-state colorant.

Further, the present invention provides a method for manufacturing a colored pencil lead, comprising the steps of:

(a) a kneading step of kneading the host material and the inorganic binder to prepare a mixture;

(b) an extrusion step of extruding the mixture to produce a linear molded article;

(c) a firing step of firing the linear molded product to produce a porous base material;

(d) an impregnation step of bringing a solution or dispersion containing a colorant and a low-viscosity organic solvent into contact with the porous substrate to impregnate the porous substrate with the solution or dispersion;

(e) a drying step of heating the porous base material after the impregnation step to remove a part or all of the low-viscosity organic solvent in the pores, thereby leaving the solid colorant in the pores and forming voids to form a porous core;

(f) and a filling step of bringing a nonvolatile liquid into contact with the porous core and filling the nonvolatile liquid into the voids.

Effects of the invention

When writing is performed using the colored pencil lead of the present invention, the colorant can be prevented from penetrating into the paper, and when erasing is performed using an eraser, the colorant present on the paper surface can be easily removed, so that excellent erasing properties can be achieved. Further, the impregnation of the nonvolatile liquid gives a smooth writing feeling, and the physical strength of the colored pencil lead is increased, so that the colored pencil lead is not easily broken.

Detailed Description

< colour pencil lead >

The colored pencil lead comprises a porous core and a nonvolatile liquid filled in air holes of the porous core. These structures are explained below.

The porous core for the colored pencil lead of the present invention comprises a host material and an inorganic binder material as main components. Examples of the host material 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. The colored pencil lead of the present invention is expected to form vivid handwriting. In addition, in the case of forming a handwriting of a fluorescent color by using a fluorescent colorant as a colorant, it is preferable not to hinder the color development thereof. Therefore, in order to form a handwriting with high brightness, it is preferable to use a white host material. In particular, when boron nitride is used, the host material does not inhibit color development, and the strength of the colored pencil lead is high, which is preferable.

Examples of the inorganic binder include: clays such as kaolins, halloysites, montmorillonites, sericites, and bentonites, ceramics, zeolites, diatomaceous earth, activated clay, silica, aluminum phosphate, silicone resins, and silicone rubbers, and these materials may be used alone or in combination.

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

In the present invention, the solid colorant may be locally present in a part of the porous base material mainly composed of the host material and the inorganic binder, or may be uniformly dispersed in the entire porous base material. Specifically, the solid colorant is preferably adhered or adsorbed in the pores of the porous base material. In this way, the colorant exists in a solid state in the porous core and in a solid state in the final colored pencil lead, whereby the colorant can be inhibited from penetrating into the paper during writing, and the erasing property can be improved. Here, typically, the solid colorant forms a layer or phase within the pores. That is, the pores are usually formed in a uniform or non-uniform layer on the inner surface thereof, or attached in a block form. The solid colorant may be in a completely dried state or in a solvated state. That is, a small amount of a solvent or the like may be contained in a range where the layer or the phase does not have fluidity.

In the present invention, the porous core is composed of a host material, an inorganic binder, and a solid colorant. Generally, a pencil lead is produced by molding a mixture of a host material and a binder and then firing the molded product. That is, the porous sintered base material can be produced by sintering a mixture of the host material and the inorganic binder to adsorb or adhere the solid colorant to the porous sintered base material (details will be described later). In addition, the host material, the inorganic binder, and the colorant may be mixed and fired, but in this case, a colorant having high heat resistance is preferably used. On the other hand, in the former method, even a colorant having low heat resistance can be used.

Further, the porous core may be produced by compressing a mixture containing the host material, the inorganic binder, the inorganic substance, the water-soluble resin, and the like, and if necessary, the solid coloring material under high pressure, and then immersing the mixture in water, a solvent, or the like to remove the inorganic substance, the water-soluble resin, and the like.

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%, and more preferably in the range of 10 to 30%. When the content is less than 5%, the amount of the solid colorant and the nonvolatile liquid present in the pores tends to be small, whereby color difference tends to occur or some resistance tends to occur during pen carriage, and when the content is more than 40%, the strength of the obtained porous core tends to be reduced and the core tends to be easily broken. When the content is in the range of 5 to 40%, the color rendering property is also good, the writing feeling is smooth, and the strength of the fired colored pencil lead can be maintained, so that the content is preferable.

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 of the porous core was measured (W1). Next, the porous core is immersed in a liquid having a good permeability (for example, benzyl alcohol), and the mass in the liquid is measured after the pores of the porous core have absorbed the liquid until the liquid is saturated (W2). Further, the porous core was taken out from the liquid, and the liquid adhered to the surface thereof was removed, followed by measurement of the saturated liquid mass (W3). Using these measured values, the porosity was determined by the following numerical expression (1).

Porosity (W3-W1)/(W3-W2) × 100(1)

As the solid colorant, a dye or a pigment may be used. In addition, a colored pigment obtained by coloring a resin with a dye may be used. In general, although the heat resistance of the dye is sometimes low, the dye is likely to permeate into the porous core when made into a solution, and therefore, the pencil lead of the present invention can be easily produced. Therefore, the solid colorant is preferably a dye.

The dye that can be used in the present invention is not particularly limited, and general dyes and fluorescent dyes can be mentioned.

Examples of the general dye include oil-soluble dyes, acid dyes, basic dyes, gold-containing dyes, and the like. In addition, as salt-forming dyes and the like of these dyes, there can be mentioned: salt-forming dyes of acid dyes and basic dyes, salt-forming dyes of basic dyes and organic acids, salt-forming dyes of acid dyes and organic amines, salt-forming dyes of basic dyes and resin acids and the like. Among these dyes, a salt-forming dye is preferable from the viewpoints of color developability, permeability into a porous core when prepared into a solution, and dissolution stability when prepared into a solution. In addition, since the solution has high dissolution stability when prepared into a solution and the effect of the present invention can be more effectively exhibited, the solution is preferably selected from the group consisting of a salt-forming dye of an organic acid and a basic dye, a salt-forming dye of an acid dye and an organic amine, and a salt-forming dye of a basic dye and a resin acid, and most preferably a salt-forming dye of an organic acid and a basic dye.

More specifically, there may be mentioned: valifast Black 1802, Valifast Black 1805, Valifast Black 1807, Valifast Violet 1701, Valifast Violet 1704, Valifast Violet 1705, Valifast Blue 1601, Valifast Blue 1605, Valifast Blue 1613, Valifast Blue 1621, Valifast Blue 1631, Valifast Red 1320, Valifast Red 1355, Valifast Red 1360, Valifast Yellow 1101, Valifast Yellow 1151, Nigrostine Base EXBP, Nigrostine Base EX, BASE OF BASIC DYES ROB-B, BASE IC DYES RO6 383538-B, BASE DYE VPB-B, BASE OF VB-B, BASE VB-B, BlifASYE 3-B, BASE SAIL 3-B, BASE SAGE MIXO 3-B, BASE SAGE MIXON BRYOB-3, BASE MIXON SANYOB, BASE MIXON, BASE OF-B, BASE MIXON SAXON SALTO 3, BASE SALTO 3-B, BASE SALTO-B, BASE SALTS SALKAXON BIN 3, BASE MIXON BIN B, BASE MIXON BIN-B, BASE MIXON BIN, BASE MIXEL 3, BASE MIXON BIN-B, BASE MIXEL 3, BASE MIXEL NO 3, BASE SALTS NO 3, BASE BIN, BASE BIN, BASE B, BASE BIN, BASE BIN, BASE BIN, BASE BIN, BASE BIN, BASE BIN, BASE BIN, BASE BIN, BASE B, BASE B, and dyes such as Aizen Spilon Red C-BH, Aizen Spilon Red C-PH, Aizen Spilon Yellow C-GNH, Aizen Spilon 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.B.N.blue 570, and Spilon Red C-BH (Saturgo chemical industries, Ltd.).

Examples of fluorescent dyes include: basic yellow 1, basic yellow 40, basic red 1:1, basic red 13, basic violet 1, basic violet 7, basic violet 10, basic violet 11:1, basic orange 22, basic blue 7, basic green 1, acid yellow 3, acid yellow 7, acid red 52, acid red 77, acid red 87, acid red 92, acid blue 9, disperse yellow 121, disperse yellow 82, disperse yellow 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, solvent green 7, and the like.

These dyes may also be used alone or in combination of 2 or more in a range not affecting the performance of the colored pencil lead in order to adjust the color of handwriting and the like. In addition, other dyes may be used in combination with these dyes. In addition, a colored pigment obtained by coloring a resin with a dye may be used.

As the solid colorant, any pigment may be used. In addition, ultrafine pigments, processed pigments, or the like may also be used.

However, when a solid colorant is combined with a porous base material to form a porous core, the production is facilitated by impregnating the porous base material including a host material and an inorganic binder with a colorant solution in which the colorant is dissolved in a solvent, for example, a low-viscosity organic solvent, and then removing the solvent (details will be described later). In the present invention, the low-viscosity organic solvent means a solvent having a viscosity of 20 mPas or less at 20 ℃. Thus, the colorant used is preferably a dye, preferably a dye soluble in low viscosity organic solvents. Here, soluble means that 5g or more of the solvent is dissolved in 100g of the solvent at 20 ℃. In addition, in order to facilitate the removal of the solvent, it is preferable to use a low-viscosity organic solvent, and the boiling point of the solvent is preferably low. Specifically, a solvent that volatilizes at a temperature at which the dye does not discolor is preferable, and a solvent that volatilizes at 100 ℃ is preferable. More preferably an aliphatic alcohol having 1 to 4 carbon atoms.

The content of the solid colorant relative to the total mass of the colored pencil lead varies depending on the kind thereof, but is preferably 0.2 to 20 mass%, more preferably 0.3 to 18 mass%, and particularly preferably 0.5 to 15 mass%.

The colored pencil lead of the invention is filled with the nonvolatile liquid in the pores of the porous base material. The less volatile liquid improves the feeling of writing during writing.

In the present invention, the less volatile liquid means a liquid which is less volatile at ordinary temperature. By using such a sparingly volatile liquid, the stability of the colored pencil lead over time can be maintained at a high level. Specifically, the less volatile liquid is preferably a liquid that does not volatilize at 250 ℃ or lower. In addition, the less volatile liquid preferably has a low viscosity so as to facilitate impregnation into pores of the porous substrate.

In addition, the surface tension of the less volatile liquid is preferably 35mN/m or less, more preferably 30mN/m or less, and still more preferably 25mN/m or less, from the viewpoint of obtaining a colored pencil lead which is excellent in impregnation into the pores of the porous core, is uniform in the less volatile liquid, is uniformly impregnated into the entire porous core, and is excellent in writing feeling and erasing feeling. Here, the surface tension can be measured by the method prescribed in JIS K2241 at a temperature of 25 ℃.

Further, the dynamic viscosity of the nonvolatile liquid is preferably 10000mm²Less than s, more preferably 1000mm²A thickness of 500mm or less, preferably 500mm²The ratio of the water to the water is less than s. In addition, the dynamic viscosity of the nonvolatile liquid is preferably 1mm²More preferably 5 mm/s or more²At least s, more preferably 10mm²More than s. If the dynamic viscosity of the sparingly volatile liquid is 10000mm²When the concentration is less than s, the nonvolatile liquid is likely to be uniformly impregnated into the entire porous core without unevenness. Further, if the dynamic viscosity of the nonvolatile liquid is 1mm²When the amount of the non-volatile liquid is larger than s, the non-volatile liquid is easily filled in pores of the porous substrate. The dynamic viscosity can be determined here at a temperature of 25 ℃.

Specific examples of preferred less volatile liquids include liquids selected from the group consisting of silicone oils, fluorine-based oils, mineral oils, vegetable oils, paraffins, polyol esters, and α -olefins, and among these, silicone oils are more preferred. Since silicone oil has a small viscosity change due to temperature and is excellent in stability, use of silicone oil as a nonvolatile liquid makes it a colored pencil lead less susceptible to environmental changes and aging, and when the colored pencil lead is used for a mechanical pencil, the colored pencil lead is less susceptible to corrosion of the opening at the tip of the mechanical pencil made of a metal material, and components such as a chuck and a lead holder. The silicone oil is particularly preferably dimethyl silicone or methylphenyl silicone, and modified silicone is also preferably used. In addition, the solid colorant described above is preferably not easily dissolved. By making the solid colorant insoluble, the penetration of the solid colorant into the paper together with the nonvolatile liquid can be suppressed in the formed handwriting, and the erasing property can be improved.

The paraffin wax, the polyol ester, or the α -olefin preferably has 14 or more carbon atoms.

The content of the nonvolatile liquid is preferably 4.5 to 20 mass%, more preferably 7 to 18 mass%, and particularly preferably 9.5 to 15 mass% with respect to the total mass of the colored pencil lead.

The colored pencil lead of the present invention may also contain various additives within a range that does not affect its properties. These additives are preferably contained in the colored pencil lead in a solid state under normal temperature conditions, and more preferably additives having a high melting point. Specifically, the melting point is preferably 50 ℃ or higher, more preferably 100 ℃ or higher, and particularly preferably 200 ℃ or higher. Specific examples of the additives include phenol compounds, surfactants, preservatives, mildewcides, and resins.

Of these additives, phenol compounds are preferred because they improve the bending strength of the colored pencil lead and further have the effect of suppressing the strength from decreasing even in a high-temperature and high-humidity environment.

Examples of such a phenol compound include:

(i) phenol compounds having one phenol structure, for example:

2-hydroxy-5-methyl-1, 3-benzenedimethanol (melting point, about 128 ℃ C.), etc.,

(ii) phenol compounds having two phenol structures, for example:

bisphenol A (melting point, about 158 ℃ C.),

1, 1-bis (4-hydroxyphenyl) -ethane,

1, 1-bis (4-hydroxyphenyl) -propane,

1, 1-bis (4-hydroxyphenyl) -n-butane,

1, 1-bis (4-hydroxyphenyl) -n-pentane,

1, 1-bis (4-hydroxyphenyl) -n-hexane,

1, 1-bis (4-hydroxyphenyl) -2-ethylbutane,

1, 1-bis (4-hydroxyphenyl) -2-methylpentane,

1, 1-bis (4-hydroxyphenyl) -n-heptane,

1, 1-bis (4-hydroxyphenyl) -2, 3-dimethylpentane,

1, 1-bis (4-hydroxyphenyl) -n-octane,

1, 1-bis (4-hydroxyphenyl) -2-ethylhexane,

1, 1-bis (4-hydroxyphenyl) -n-nonane,

1, 1-bis (4-hydroxyphenyl) -n-decane,

1, 1-bis (4-hydroxyphenyl) -3, 7-dimethyloctane,

1, 1-bis (4-hydroxyphenyl) -n-undecane,

1, 1-bis (4-hydroxyphenyl) -n-dodecane,

1, 1-bis (4-hydroxyphenyl) -n-tridecane,

1, 1-bis (4-hydroxyphenyl) -n-tetradecane,

1, 1-bis (4-hydroxyphenyl) -n-pentadecane,

1, 1-bis (4-hydroxyphenyl) -n-hexadecane,

1, 1-bis (4-hydroxyphenyl) -1-methylpropane,

2, 2-bis (4' -hydroxyphenyl) -6,10, 14-trimethylpentadecane 2, 2-bis (4-hydroxyphenyl) propane,

2, 2-bis (4-hydroxyphenyl) hexafluoropropane,

4, 4' - (1-alpha-methyl-benzylidene) bisphenol,

(iii) phenol compounds having 3 phenol structures, for example:

4, 4' -ethylidenetris (2-methylphenol),

4, 4' -ethylidenetrisphenol (melting point, about 246 ℃), and,

4, 4' - (1-phenylethane-1, 1-diyl) bis (2-methylphenol),

1,1, 1-tris (4-hydroxyphenyl) ethane and the like,

(iv) phenol compounds having 4 phenol structures, for example:

4, 4' - [4- (4-hydroxyphenyl) butane-2, 2-diyl ] diphenol, and

4, 4' - [3- (4-hydroxyphenyl) -1-methylpropylidene ] bis (2-methylphenol),

4, 4' -dihydroxytetraphenylmethane, and the like.

In addition, (v) a phenol compound having 5 or more phenol structures may also be used.

In general, the more the phenol structure is, the greater the strength-improving effect of the colored pencil lead, but the phenol compound of (iii) or (iv) is easily contained in the colored pencil lead, and the bending strength-improving effect of the colored pencil lead is remarkable, so that it is preferable. Further, the phenol compound of (iii) is more preferably used, and among them, the phenol compound represented by the following formula (I) is particularly preferably used.

(in the formula (I), the compound (I),

R¹hydrogen or an alkyl group having 1 to 3 carbon atoms,

R²each independently an alkyl group having 1 to 10 carbon atoms,

n independently represents a number of 0 to 2. )

Of the phenol compounds represented by the formula (I), 4 '-ethylidenetris (2-methylphenol) or 4, 4' -ethylidenetrisphenol is most preferable.

The content of the phenol compound relative to the total mass of the colored pencil lead varies depending on the kind thereof, but is preferably 0.1 to 10 mass%, more preferably 0.2 to 5 mass%.

The shape of the colored pencil lead of the present invention is not particularly limited, and is generally a linear body having a circular cross section. The size of the colored pencil lead is, for example, 0.2 to 2.0mm, preferably 0.3 to 0.7mm in cross-sectional diameter. The length is preferably 30 to 100mm, and more preferably 40 to 70 mm. When the colored pencil is applied to a general colored pencil held by a support such as wood, the cross-sectional diameter is preferably 0.5 to 3.0mm, and more preferably 0.8 to 2.0 mm. In general, a long colored pencil lead is often cut by sandwiching it between wood or the like in the manufacturing process, and therefore the length is not limited, but is usually 1,000mm or less.

The colored pencil lead of the present invention can realize high physical strength when a porous base material produced by firing is used. This is considered to be because the solid colorant forms a uniform or non-uniform layer on the inner side of the pores, or adheres to the inner side of the pores in a lump. The bending strength of the colored pencil lead of the present invention is preferably 120MPa or more. More preferably 180MPa or more. Here, the bending strength can be determined by JIS S6005: 2007.

Method for making colour pencil lead

The method for manufacturing the colored pencil lead of the present invention is not particularly limited. However, it is preferably produced by a method including the steps of:

(d) an impregnation step of bringing a solution or dispersion containing a colorant and a low-viscosity organic solvent into contact with the porous base material to impregnate the porous base material with the solution or dispersion;

(f) and a filling step of bringing a less volatile liquid into contact with the porous core and filling the voids with the less volatile liquid.

This method will be explained below.

(a) Kneading step

First, a host material and an inorganic binder are kneaded to prepare a mixture. The mixture becomes the main component of the porous base material. In the mixing, an organic solvent, a plasticizer, and the like may be added as necessary. The organic solvent used here is a solvent that is substantially completely removed in the firing step while maintaining fluidity of the raw material mixture and making the mixture homogeneous, and is independent of the low-viscosity organic solvent and the nonvolatile liquid.

(b) Extrusion process

Subsequently, the resulting mixture was extruded to produce a linear molded article. The colored pencil lead of the present invention is preferably formed into a linear body having a generally circular cross-sectional shape, and therefore, a linear molded product is formed by extrusion molding.

(c) Firing Process

The obtained linear molded product is dried and fired as necessary to prepare a porous base material. The organic solvent contained in the mixture is removed by firing, and the host material and the inorganic binder are sintered to form a porous base material. The firing conditions are not particularly limited as long as the material is sintered to form a porous base material, and the maximum temperature may be 650 to 1000 ℃. In order to avoid a rapid temperature change, the temperature during firing may be increased continuously or stepwise. The temperature rise rate in this case may be, for example, 10 to 100 ℃/hr. Further, it is also preferable that the firing is performed at a constant temperature for a certain time, for example, about 0.5 to 2 hours after the temperature is raised to the set temperature. These conditions may be arbitrarily combined according to the purpose. For example, the temperature may be raised from room temperature to 650 ℃ at 10 ℃/hr in an oxygen atmosphere, and then the temperature may be maintained at 650 ℃ for 1 hour to perform firing; or heating from room temperature to 1000 deg.C at 100 deg.C/hr, and maintaining at 1000 deg.C for 1 hr.

(d) Impregnation step

After cooling the formed porous substrate as necessary, the porous substrate is brought into contact with a solution or dispersion containing a colorant and a low-viscosity organic solvent. In this step, the coloring agent permeates into pores present in the porous base material. As the impregnation method, a normal pressure impregnation method, a reduced pressure impregnation method, or a pressure impregnation method can be used.

The content of the colorant in the solution or dispersion is not particularly limited, but the concentration of the colorant is preferably 5 to 50% by mass, more preferably 5 to 45% by mass, and particularly preferably 10 to 40% by mass, based on the total mass of the solution or dispersion. When the amount is more than this range, the color developability tends not to be improved in accordance with the amount of the colorant added, and the stability of the solution or dispersion with time may be low, for example, the colorant may precipitate with time. In addition, when a colorant capable of providing sufficient color developability even at a low concentration is used, or when erasure is more important (for example, when the colorant is used as a chalk for a tailor), a solution or a dispersant having a lower concentration may be used. In this case, specifically, the concentration of the colorant is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass.

Additives such as phenol compounds, surfactants, preservatives, mildewcides, and resins are preferably introduced into the solution or dispersion containing the colorant because they can be efficiently contained in the colored pencil lead.

(e) Drying step

Next, the porous substrate after the impregnation step is heated to remove a part or all of the low-viscosity organic solvent contained in the solution or dispersion impregnated in the pores. As a result, the solid colorant remains, adsorbs, or adheres to the inside of the pores. Further, the porous core is formed by removing the low-viscosity organic solvent to form voids. The drying conditions are not particularly limited as long as the low-viscosity organic solvent is sufficiently removed, and for example, the drying is preferably performed at a temperature of +0 to +10 ℃ which is the boiling point of the low-viscosity organic solvent.

(f) Filling process

The formed porous core is cooled as necessary and then contacted with a less volatile liquid. Through this step, the voids formed in the porous core are filled with the nonvolatile liquid. The conditions in this case are not particularly limited, and for example, a temperature of 60 ℃ for 6 to 12 hours may be used. For filling the nonvolatile liquid, a normal pressure impregnation method, a reduced pressure impregnation method, or a pressure impregnation method can be used.

The colored pencil lead of the present invention can be obtained by further washing or the like as required.

Examples

Hereinafter, examples of the present invention will be described, but the present invention is not limited to the examples.

[ example 1]

[ kneading step, extrusion step, and firing step ]

The above-mentioned complex is heated and kneaded while evaporating water by a kneader or three rolls, and the resulting kneaded product is extruded to a predetermined diameter to obtain a linear molded product. The linear molding in argon, heating rate 10 ℃/h to 600 degrees C, and holding for 5 hours, then, set to oxygen atmosphere at 100 ℃/hr, and 900 degrees C firing for 1 hours, get the porosity of 25%, the cross section diameter is 0.55mm porous substrate.

[ impregnation step ]

70 parts by mass of ethanol

Yellow common dye 30 parts by mass

(salt-forming dye of basic dye and organic acid, manufactured by Baogu chemical industries, Ltd., trade name: Aizen Spilon Yellow C-GNH)

The above-mentioned complex was stirred at 60 ℃ until uniformly mixed to obtain a colorant solution (1).

The porous base material obtained in the firing step was immersed in the colorant solution (1) in a state of being heated to 60 ℃ and kept for 6 hours.

[ drying Process ]

The porous base material having undergone the impregnation step was held at 80 ℃ for 6 hours, and the low-viscosity organic solvent in the pores of the porous base material was evaporated to obtain a porous core.

[ filling Process ]

As the nonvolatile liquid (1), silicone oil was used. Specifically, the porous core obtained in the drying step was immersed in silicone oil (product name: KF-96-50cs, manufactured by shin-Etsu chemical Co., Ltd.) in a state of being heated to 80 ℃ and kept for 6 hours to obtain a colored pencil lead. Next, the surface of the colored pencil lead was cleaned with ethanol, and an excessive amount of a nonvolatile liquid adhering to the surface was removed to obtain a colored pencil lead impregnated with 17.5 mass% of silicone oil.

The contents of the solid colorant and the nonvolatile liquid were 7.5% and 12.5%, respectively, with respect to the total mass of the colored pencil lead thus obtained.

[ examples 2 to 17]

A colored pencil lead was obtained in the same manner as in example 1 except that the colorant solution (1) or the less volatile liquid (1) was changed to the liquid described in table 1.

Comparative example 1

A porous substrate was obtained in the same manner as in example 1.

Then, the following complex was heated to 70 ℃ and stirred to be uniformly mixed, thereby obtaining a colorant solution (5).

Diethylene glycol monobenzyl ether 70 parts by mass

Yellow common dye 30 parts by mass

Then, the porous base material was immersed in the colorant solution (5) while being heated to 60 ℃ and kept for 6 hours, thereby obtaining a colored pencil lead.

Comparative example 2

A porous substrate was obtained in the same manner as in example 1. Then, the colorant (1) was impregnated and dried in the same manner as in example 1 to obtain a porous core. Then, the colored pencil lead is prepared without a filling process. That is, the colored pencil lead of comparative example 2 was not filled with a nonvolatile liquid.

Comparative examples 3 and 4

A porous substrate was obtained in the same manner as in example 1. Then, the colorant (1) was impregnated and dried in the same manner as in example 1 to obtain a porous core. Then, diethylene glycol monobenzyl ether (comparative example 3) or isododecane (comparative example 4) was filled as a filling liquid for comparison in place of the less volatile liquid (1), to obtain a colored pencil lead.

[ evaluation ]

The properties of the obtained colored pencil leads were evaluated by the following methods.

[ evaluation method of initial handwriting Erasure (Erasure 1) ]

The erasing ability of the plastic eraser disclosed in JIS S6050-. The conventional product is an automatic pencil lead manufactured by seoul corporation "trade name: neox Color Eno (yellow) ".

A: very good.

B: is better than the existing products.

C: as with existing products.

[ evaluation method of handwriting Erasure after elapse of time (Erasure 2) ]

The erasing property at this time was evaluated by a sensory test by erasing the handwriting according to the erasing ability test of the plastic eraser disclosed in JIS S6050-. The conventional product is an automatic pencil lead manufactured by seoul corporation "trade name: neox Color Eno (yellow) ".

A: very good.

B: is better than the existing products.

C: as with existing products.

[ evaluation method of initial writing feeling (writing feeling 1) ]

Using a colored pencil lead, a high-quality paper (paper corresponding to writing paper A specified in JIS P3201. 100% chemical pulp was used as a raw material for paper making, and the basis weight was 40 to 157g/m²White degree of 75.0% or more) and the sense of writing was evaluated by a sensory test.

A: writing can be done very smoothly.

B: can write smoothly.

C: the pen feel was slightly heavier.

D: the feeling of writing is rough and heavy.

[ evaluation method of feeling of writing after elapse of time (feeling of writing 2) ]

The fired colored pencil lead was used, which was left to stand at 25 ℃ for 4 weeks after the production, and the writing was performed on the above-mentioned high-quality paper, and the feeling of writing at that time was evaluated by a sensory test.

A: writing can be done very smoothly.

B: can write smoothly.

C: the pen feel was slightly heavier.

D: the feeling of writing is rough and heavy.

[ method for evaluating flexural Strength ]

The average value of the values measured for 10 specimens at an inter-fulcrum distance of 20mm was measured by the method prescribed in JIS S6005-2007.

[ Table 1-1]

TABLE 1-1

[ tables 1-2]

Tables 1 to 2

In the table:

dye Y: aizen Spilon Yellow C-GNH (salt-forming dye of basic dye and organic acid, manufactured by Baogu chemical Co., Ltd.)

A dye R: aizen Spilon Red C-PH (salt-forming dye of basic dye and organic acid, manufactured by Baogu chemical Co., Ltd.)

Dye B1: valifast Blue 1613 (salt-forming dye of basic dye and organic acid, オリエント chemical industry Co., Ltd.)

Dye B2: S.B.N.blue 570 (salt-forming dye of acid dye and organic amine, manufactured by Baotai ケ grain industries, Ltd.)

Compound P1: 4, 4', 4 "-ethylidenetris (2-methylphenol)

Compound P2: bisphenol A

Compound P3: 2-hydroxy-5-methyl-1, 3-benzenedimethanol (product of Kyowa Kagaku Co., Ltd., trade name: DML-PC)

Compound P4: 4, 4' -ethylidene trisphenol (product of Kyowa Kagaku K.K.: TrisP HAP)

EtOH: ethanol

PrOH: isopropanol (I-propanol)

DEGMBE: diethylene glycol monobenzyl ether (boiling point: 302 ℃ C.)

SO 1: silicone oil (trade name: KF-96-50cs, manufactured by shin-Etsu chemical Co., Ltd.), Dimethicone, surface tension: 20.8N/m, dynamic viscosity: 50mm²/s)

SO 2: silicone oil (trade name: KF-50-100cs, manufactured by shin-Etsu chemical Co., Ltd.), Methylphenyl Silicone oil, surface tension: 21.8N/m, dynamic viscosity: 100mm²/s)

OO: vegetable oil (olive oil, manufactured by Nisshin オイリオグループ K.K.: BOSCO olive oil, surface tension: 32mN/m)

PE: polyol ester (manufactured by Nichii oil Co., Ltd., trade name: HR-170R)

And (3) LP: paraffin (Mobile Paraffin, product of Sansho chemical industries Co., Ltd.; trade name: No.150S)

HC: mineral oil (Petroleum hydrocarbon, product name of Standard petroleum of Kabushiki Kaisha: YUBASE 4)

TD: alpha-olefin (1-tetradecene, trade name: Linearen 14, available from shinxinko Co., Ltd.)

ID: isododecane (product of Wanshan Petroleum Co., Ltd., trade name: MARUKASOL R, boiling point: 177 ℃ C.)

Claims

1. A colored pencil lead, comprising:

a porous core, and

a nonvolatile liquid filled in the pores of the porous core,

2. The colored pencil lead of claim 1, the less volatile liquid is a liquid selected from the group consisting of silicone oil, fluorine-based oil, mineral oil, vegetable oil, paraffin wax, polyol ester and α -olefin.

3. A colored pencil lead according to claim 1 or 2, said solid-like colorant being a dye soluble in low viscosity organic solvents.

4. The colored pencil lead according to any one of claims 1 to 3, wherein the host material is selected from the group consisting of titanium oxide, mica, talc, boron nitride, aluminum oxide and calcium carbonate.

5. The colored pencil lead according to any one of claims 1 to 4, wherein the inorganic binding material is selected from the group consisting of clay, ceramics, zeolite, diatomaceous earth, activated clay, silica, aluminum phosphate, silicone resin, and silicone rubber.

6. The colored pencil lead according to any one of claims 1 to 5, wherein the porosity of the porous core is 5 to 40%.

7. A colored pencil lead according to any one of claims 1 to 6, said porous core being a fired core.

8. A colored pencil lead according to any one of claims 1 to 7, further comprising a phenolic compound.

9. A method for manufacturing a colored pencil lead is characterized by comprising the following steps:

10. The method of claim 9, the colorant does not change color at temperatures at which the low viscosity organic solvent volatilizes.