WO2022210535A1 - Color pencil lead, method for manufacturing color pencil lead, and refill product comprising color pencil lead and refill case in which same is accommodated - Google Patents

Abstract

[Problem] To provide: a color pencil lead having exceptional color development and erasability of writing, a smooth feel, and exceptional storage stability; a method for manufacturing a color pencil lead; and a refill product comprising a color pencil lead and a refill case in which the same is accommodated. [Solution] The color pencil lead according to the present invention includes: a porous lead body that contains a body material, an inorganic binder, a coloring agent, and a high-boiling-point organic solvent having a boiling point of 250°C or higher; and a refractory liquid with which the pores of the porous lead body are filled. The color pencil lead includes bringing a coloring agent solution that contains a coloring agent and a high-boiling-point organic solvent into contact with a porous lead body obtained through firing, furthermore bringing the coloring agent into contact with an insoluble refractory liquid, and filling the voids in the porous lead body with the refractory liquid. The refill product according to the present invention comprises the color pencil lead and a case.

Description

A colored pencil lead, a manufacturing method for a colored pencil lead, and a replacement lead product comprising a colored pencil lead and a replacement lead case containing the lead

The present invention relates to a colored pencil lead. More specifically, it relates to a colored pencil lead which is excellent in coloring and has a smooth writing feel.

Conventionally, colored pencil leads used in mechanical pencils and the like are mainly composed of an extender such as boron nitride and a binder such as clay. A white porous substrate obtained by firing at a high temperature is impregnated with an ink containing a dye in the pores thereof. For such colored pencil leads, it is desirable to use various materials and equipment to achieve better color development in order to express a variety of color tones. is also desired to be improved.

JP 2019-099633 A

The present invention provides a colored pencil core which is excellent in handwriting color development, has high stability over time, and provides a smooth writing feel.

The colored pencil lead according to the present invention is
body material and
an inorganic binder;
a coloring agent;
a porous core containing a high-boiling organic solvent capable of dissolving the coloring agent and having a boiling point of 250° C. or higher;
The coloring agent, the high-boiling organic solvent, and the low-volatility liquid are filled in the pores of the porous core.

Further, the method for producing a colored pencil lead according to the present invention comprises:
(a) a kneading step of kneading an extender and an inorganic binder to prepare a mixture;
(b) an extrusion step of extruding the mixture to form a linear form;
(c) a sintering step of sintering the linear molded product to create a porous substrate;
(d) an impregnation step of contacting and impregnating the porous substrate with a coloring agent solution containing a coloring agent and a high-boiling organic solvent having a boiling point of 250° C. or higher;
(e) a drying step of heating the porous substrate after the impregnation step at a temperature of 200° C. or less to form a porous core;
(f) A filling step of contacting the porous core with a refractory liquid in which the colorant cannot be dissolved, and filling the voids of the porous core with the refractory liquid. It is characterized by

By writing with the colored pencil lead according to the present invention, it is possible to form handwriting with excellent coloring. In addition, a smooth writing feeling can be obtained when writing with the core of the colored pencil according to the present invention. In addition, the colored pencil lead according to the present invention has high storage stability, and is excellent in color developability and erasability over time.

1 is a perspective view of a refill product according to the present invention; FIG. FIG. 2 is a vertical cross-sectional view of a refill case that can be used in the present invention. Fig. 2 is a cross-sectional view of a refill lead case that can be used in the present invention; FIG. 4 is a longitudinal sectional view of another refill case that can be used in the present invention. FIG. 10 is a cross-sectional view of another refill lead case that can be used in the present invention; FIG. 10 is a vertical cross-sectional view of still another refill case that can be used in the present invention. FIG. 10 is a cross-sectional view of still another extra lead case that can be used in the present invention.

<Colored pencil lead>
The configuration of the colored pencil lead according to the present invention is described below.

The porous core used for the colored pencil core of the present invention contains a filler and an inorganic binder as main components. Examples of the filler include white ones such as titanium oxide, mica, talc, boron nitride, alumina and calcium carbonate, and colored ones such as molybdenum disulfide, tungsten disulfide and graphite. It is desirable that the colored pencil lead according to the present invention forms vivid handwriting. Further, when a fluorescent colorant is used as the colorant to form a fluorescent color handwriting, it is preferable that the colorant does not hinder the color development. For this reason, it is preferable to use a white filler in order to form handwriting with high brightness. In particular, it is preferable to use boron nitride because the extender does not interfere with the 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, aluminum phosphate, silicone resins, and silicone rubbers. etc., and these can be used singly or in combination.

Although the compounding ratio of the filler and the inorganic binder, which are the main components of the porous core, is not particularly limited, it is preferably 9:1 to 7:3 in mass ratio.

In the present invention, the porous core is typically a combination of a porous base material, a coloring agent and a high boiling point organic solvent. The coloring agent may be localized in a part of the porous substrate containing an extender or an inorganic binder as a main component, or may be dispersed uniformly throughout the porous substrate. It is preferably localized in a part of the sex core. Specifically, it is preferable that the coloring agent is adhered or adsorbed in the pores of the porous substrate. At this time, the coloring agent may be in the state of fine particles or in the state of being dissolved or dispersed in a high boiling point organic solvent, which will be described later. When the coloring agent is present in the final colored pencil lead in such a state, the coloring agent is prevented from penetrating into the paper during writing, and the coloring property and erasability are improved. Here, the colorant typically forms a layer or phase within the pores. That is, it generally forms a uniform or non-uniform layer or adheres to the inner surface of the pores in a mass. In the present invention, the term "pores" means pores in a base material such as a porous base material obtained by removing an organic solvent from a pencil lead. For example, in a porous core, an organic solvent or the like may penetrate into the pores, and the pores of the porous core mean the pores after removing the organic solvent or the like from the porous core. .

In the present invention, the porous core contains a filler, an inorganic binder, a coloring agent, and a high-boiling organic solvent. A pencil lead is generally manufactured by molding a mixture of an extender and a binder and then firing the molded mixture, but the same method can be applied to the present invention. That is, it can be produced by baking a mixture of an extender and an inorganic binder, and adsorbing or adhering a coloring agent and a high boiling point organic solvent to the formed porous substrate (details will be described later). Alternatively, the filler, the inorganic binder, the coloring agent, and the high boiling point organic solvent may be mixed and baked. It is preferred to use a boiling point organic solvent. On the other hand, with the former method, even a coloring agent with low heat resistance and a high boiling point organic solvent having a boiling point lower than the firing temperature can be used.

In addition, a mixture containing an extender, an inorganic binder, an inorganic substance, a water-soluble resin, and, if necessary, a coloring agent is compressed under high pressure, and then immersed in water or a solvent to remove the inorganic substance or the water-soluble resin. A porous core can also be produced by removing the water-soluble resin or the like.

The porosity of the porous core used in the present invention is not particularly limited, but is preferably in the range of 1 to 50%, more preferably in the range of 5 to 50%, and more preferably in the range of 10 to 40%. is more preferable, and a range of 20 to 40% is particularly preferable. If the porosity is less than 1%, the amount of the coloring agent and the refractory liquid present in the pores is reduced, resulting in poor color development and a slight resistance to writing. There is a tendency that the strength of the porous core thus formed is reduced and that it is likely to break. When the porosity is in the range of 1 to 50%, the coloring property is good, the writing feeling is smooth, and the strength of the fired colored pencil core can be maintained, which is preferable.　

The porosity of the porous base material 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 substrate is measured. Next, the substrate is immersed in a highly permeable liquid (for example, benzyl alcohol) to allow the pores of the porous substrate to absorb the liquid until it is saturated, and then the weight in the liquid (W2) is measured. Further, the porous substrate is taken out of the liquid, and after removing the liquid adhering to the surface thereof, the liquid-saturated mass (W3) is measured. Using these measured values, the porosity is determined by the following formula (1).

Porosity = (W3-W1)/(W3-W2) x 100 (1)

The porosity of the colored pencil lead or porous core can also be measured by the same method. However, before applying the measuring method for the porosity of the porous substrate, it is necessary to remove the organic solvent or the like by heating or reducing the pressure. When measuring the porosity of a colored pencil lead or a porous core body, even if the solvent or the like is removed, a small amount of the organic solvent or the like may remain in the pores. Therefore, there may be a slight difference between the porosity of the porous substrate and the porosity of the colored pencil lead or the porous core. Taking such differences into account, the porosity of the porous substrate is preferably in the range of 5-50%, more preferably in the range of 10-40%, and more preferably in the range of 20-40%. It is particularly preferred to have

A dye or pigment can be used as the coloring agent. Also, a colored pigment obtained by dyeing a resin with a dye or the like can be used. In general, dyes may have low heat resistance, but they easily penetrate into porous substrates when taken as a solution, which facilitates the production of the pencil lead according to the present invention. Therefore, the coloring agent is a dye. is preferred.

The 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, acid dyes, basic dyes, and metal dyes. Salt-forming dyes of these dyes include salt-forming dyes of an acid dye and a basic dye, salt-forming dyes of a basic dye and an organic acid, salt-forming dyes of an acid dye and an organic amine, and the like. More specifically, Bali Fast Black 1802, Bali Fast Black 1805, Bali Fast Black 1807, Bali Fast Violet 1701, Bali Fast Violet 1704, Bali Fast Violet 1705, Bali Fast Blue 1601, Bali Fast Blue 1605, and Bali Fast Blue 1613. , Bali fast blue 1621, Bali fast blue 1631, Bali fast red 1320, Bali fast red 1355, Bali fast red 1360, Bali fast yellow 1101, Bali fast 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.), Eizen Spiron Black GMH-Special, Eizen Spiron violet CRH, Aizen spiron blue GNH, Aizen spiron blue 2BNH, Aizen spiron blue C-RH, Aizen spiron red C-GH, Aizen spiron red C-BH, Aizen spiron red C-PH, Aizen spiron yellow C-GNH, Aizenspiron Yellow C-2GH, S.T. P. T. Blue 111, S.I. P. T. Blue GLSH-Special, S.I. P. T. Red 533, S.I. P. T. Orange 6, S.I. B. N. Violet 510, S.I. B. N. Yellow 530, S.I. R. and 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, 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, Solvent Green 7 and the like.

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

Any pigment can also be used as the coloring agent. Ultra-fine pigments, processed pigments, and the like can also be used.

In addition, it is also possible to use colored pigments obtained by dyeing resin with dyes. Such color pigments are preferable because they can improve the color developability.

Any resin such as acrylic resin, styrene-acrylonitrile resin, styrene resin, nitrogen-containing resin, polyethylene resin, or polypropylene resin can be used as the resin constituting the coloring pigment. Dyes to be combined with these resins can be selected from those described above.

Among these resins, nitrogen-containing resins or styrene-acrylonitrile resins are preferably used in consideration of solubility in high-boiling organic solvents, dispersibility and dispersion stability, and dyeability with dyes. , nitrogen-containing resins are more preferred. Among nitrogen-containing resins, melamine resins, polyamide resins, urethane resins, urea resins, benzoquanamine resins, and the like are preferable. Furthermore, among these, melamine resins or polyamide resins are preferred, and melamine resins are more preferred, from the viewpoint of dissolution stability in high boiling point organic solvents.

Examples of coloring pigments include the NKS-1000 series, MPI-500 series (manufactured by Nihon Shokuryo Kagaku Co., Ltd.), FNP series, and FM series (manufactured by Shinroihi Co., Ltd.).

These color pigments may be used in combination of two or more, for example, for the purpose of adjusting the color of the handwriting within the range that does not impair the effects of the present invention. Furthermore, dyes may be used in combination with these color pigments.

In addition, in the present invention, it is also preferable to use a fluorescent colorant. By using such a coloring agent, it is possible to obtain a handwriting having fluorescence and to obtain a handwriting that is richer in color development. This makes it easy to use not only for simply leaving characters, but also for situations such as drawing and marking.

The content of the coloring agent in the total weight of the colored pencil core varies depending on the type, but is preferably 0.1 to 30% by mass, more preferably 0.2 to 25% by mass. It is preferably 1 to 20% by mass.

When a porous substrate is combined with a coloring agent to form a porous core, the porous substrate containing the filler and the inorganic binder is impregnated with a coloring agent solution in which the coloring agent is dissolved in a solvent, and then the necessary It can be easily produced by removing part of the solvent according to (details will be described later). For this reason, it is preferable that the solvent used in the production is capable of dissolving the colorant used.

The colored pencil lead according to the present invention contains a high-boiling organic solvent capable of dissolving the colorant contained in the colored pencil lead and having a boiling point of 250°C or higher. Such a solvent can impart excellent color developability and writing feel to the lead of the colored pencil according to the present invention. In addition, since it has a high boiling point, it is difficult to volatilize during the manufacturing process and storage, and it is possible to maintain stable performance.

Here, the expression that the high boiling point organic solvent is capable of dissolving the colorant means that the solubility of the colorant in the high boiling point organic solvent is 10 g/100 g or more at 20°C. It means that 10 g or more of the colorant dissolves in 100 g. The higher the solubility of the coloring agent, the higher the storage stability of the colored pencil lead.

Although such a solvent can be arbitrarily selected in consideration of the solubility of the coloring agent used and other properties, aromatic glycol ethers or aliphatic glycol ethers are preferable. Glycol ethers contain both an ether group and a hydroxyl group in their structure, and are generally characterized by high solubility in dyes and resins, and high affinity with other organic solvents.

Specific examples of such high-boiling organic solvents include diethylene glycol monophenyl ether (phenyldiglycol, 283° C.),
diethylene glycol monobenzyl ether, (302° C.),
triethylene glycol monobutyl ether (butyl triglycol, 271° C.),
Ethylene glycol monobenzyl ether (256°C)
etc. In addition, the numerical value in a parenthesis shows a boiling point (the same applies below).

In addition, as the high-boiling organic solvent, a carboxylic acid ester of polyalkylene glycol or a carboxylic acid ester of alcohol can be used.

Furthermore, higher fatty acids and higher alcohols with a boiling point of 250°C or higher can also be used. Specifically, carboxylic acids with 10 or more carbon atoms, such as decanoic acid (259°C) and oleic acid (360°C), and alcohols with 12 or more carbon atoms, such as dodecyl alcohol (259°C) and myristyl alcohol (292°C), ). It should be noted that higher fatty acids may corrode the lead of colored pencils used in mechanical pencils and come into contact with metal parts, so care should be taken.

It should be noted that some organic solvents, even if they are liquid at normal temperature and pressure, sublimate when heated under normal pressure conditions, or denature due to chemical reactions, making it impossible to accurately measure the boiling point. Even such an organic solvent can sometimes be employed as the high boiling point organic solvent. In such a case, for example, if the weight loss rate after 30 minutes is 10% by mass or less when held at 250°C under normal pressure, the boiling point of the high boiling point organic solvent can be 250°C or higher.

The content of the high boiling point organic solvent contained in the colored pencil lead according to the present invention is appropriately adjusted according to the purpose. It is preferably 20% by mass, more preferably 1 to 15% by mass. The content of high boiling organic solvent can be measured by any method. For example, by a method such as thermogravimetry, it can be confirmed that the colored pencil lead contains a high-boiling organic solvent.

The colored pencil lead according to the present invention can contain an organic solvent (hereinafter sometimes referred to as a low boiling point organic solvent) other than the high boiling point organic solvent. The low boiling point organic solvent referred to here is also different from the low-volatility liquid described later. Specifically, it is an organic solvent having a boiling point of less than 250° C. and capable of dissolving the coloring agent. Here, the low boiling point organic solvent capable of dissolving the colorant means that the solubility of the colorant in the low boiling point organic solvent is 10 g/100 g or more at 20°C, that is, the low boiling point organic solvent at 20°C It means that 10 g or more of the colorant dissolves in 100 g. The higher the solubility of the coloring agent, the higher the storage stability of the colored pencil lead.

Among the low boiling point organic solvents, those with relatively high boiling points, for example, those with a boiling point of 150° C. or more and less than 250° C. can generally be expected to compensate for the effects such as improved writing quality obtained with high boiling point organic solvents. . In addition, those having a relatively low boiling point, for example, those having a boiling point of less than 150° C. are generally effective in reducing the viscosity of the colorant solution when the porous substrate is impregnated with the colorant during the manufacturing process. be. However, since most or all of these relatively low boiling point materials are removed during the manufacturing process, they are often rarely included in colored pencil leads. Furthermore, the boiling point of the low boiling point solvent is preferably 100° C. or lower, more preferably 90° C. or lower, even more preferably 85° C. or lower, and even more preferably 80° C. or lower.

In addition, focusing on the difference between the boiling point _BPH of the high boiling point organic solvent and the boiling point _BPL of the low boiling point organic solvent in the present invention, the difference between _BPH and _BPL is preferably 100 degrees or more, more preferably. is greater than or equal to 150 degrees. Due to the difference in boiling points between the high boiling point organic solvent and the low boiling point organic solvent, it is possible to remove only the low boiling point organic solvent in the manufacturing process described below. As a result, a colored pencil lead having excellent color developability and writing feel brought about by the high boiling point organic solvent is obtained. In addition, the high boiling point organic solvent is difficult to volatilize during the manufacturing process and storage, and can maintain stable performance.

Examples of such low boiling point organic solvents include:
triethylene glycol monomethyl ether (249° C.),
phenylcellulose (247° C.),
propylene glycol monomethyl ether (243° C.),
benzyl alcohol (205° C.),
3-methoxy-3-methyl-1-butanol (174° C.),
xylene (139°C),
toluene (111° C.),
isopropyl alcohol (82° C.),
methyl ethyl ketone (79° C.),
ethyl alcohol (78° C.),
ethyl acetate (77° C.),
Acetone (56°C)
etc.

Of these, isopropyl alcohol, methyl ethyl ketone, ethyl alcohol, ethyl acetate, or acetone are preferably used.

In the colored pencil lead according to the present invention, the pores of the above-mentioned porous core are filled with a hardly volatile liquid. This low-volatility liquid further improves the feel of writing.

In the present invention, a low-volatility liquid is a liquid that is incapable of dissolving a coloring agent and is difficult to volatilize at room temperature. Here, "insoluble" does not mean that the colorant has zero solubility, but means that it is substantially insoluble. Here, the solubility of the coloring agent in the refractory liquid is preferably lower than the solubility in the above-described high-boiling organic solvent. More specifically, the solubility of the coloring agent in the refractory liquid at 20° C. is 10 g/100 g. preferably less than, more preferably 5 g/100 g or less

Although the boiling point of the hardly volatile liquid is not particularly limited, it is preferably a liquid that does not volatilize at 250°C or lower.

By using such a low-volatility liquid, the stability of the colored pencil core over time is maintained at a high level, and the writing feel is improved. In addition, if the replacement lead product contains an organic solvent, the replacement lead and the case may fuse together in the case of the replacement lead product, but the colored pencil lead contains a refractory liquid. This makes it possible to improve such fusion.

Such improvement in fusion is also affected by the material of the case. A remarkable improvement effect is exhibited when the SP value of the resin material to be used and a specific relationship are satisfied. Although this relationship will be described later, it is generally preferable that the SP value of the hardly volatile liquid is 6-8. Here, the Fedors solubility parameter, the Hildebrand solubility parameter, the Hansen solubility parameter, etc. are known as the SP value, but the Fedors solubility parameter is used as the solubility parameter in the present invention.

Also, the low-volatility liquid preferably has a low viscosity in order to facilitate impregnation into the pores of the porous core.

In addition, the surface tension of the refractory liquid is excellent in impregnating the pores of the porous core, and the refractory liquid is impregnated evenly throughout the porous core, resulting in excellent writing and erasability. It is preferably 35 mN/m or less, more preferably 30 mN/m or less, and even more preferably 25 mN/m or less, so that a colored pencil lead with good resistance can be obtained. Here, surface tension can be measured by the method specified in JIS K2241 under conditions of a temperature of 25°C.

Specific examples of preferred low-volatility liquids include those selected from the group consisting of silicone oil, fluorine-based oil, mineral oil, vegetable oil, and liquid paraffin, with silicone oil being more preferred. Silicone oil has a small change in viscosity due to temperature and is excellent in stability. When used in a pencil, it hardly corrodes parts such as the opening at the tip of the mechanical pencil, the chuck, and the lead housing cylinder, which are made of metal materials. As the silicone oil, dimethylsilicone and methylphenylsilicone are particularly preferred, and modified silicone is also preferred. Moreover, it is preferable that the coloring agent is difficult to dissolve. By making the coloring agent difficult to dissolve, in the formed handwriting, the coloring agent is suppressed from penetrating into the paper together with the refractory liquid, and erasability can be improved. Further, liquid paraffin preferably has 14 or more carbon atoms.

The content of the hardly volatile liquid relative to the total weight of the colored pencil lead is preferably 5-40% by mass, more preferably 8-45% by mass, and more preferably 10-35% by mass.

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, antifungal agents, resins, and the like.

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

The colored pencil lead according to the present invention can achieve high physical strength by using a porous base material produced by firing. This is presumably because the coloring agent forms a uniform or non-uniform layer or adheres to the inner surface of the pores in a lump. The bending strength of the colored pencil lead according to the present invention is preferably 120 MPa or more. It is more preferably 180 MPa or more. The bending strength can be measured by the method specified in JIS S 6005:2007.

It should be noted that the colored pencil lead according to the present invention can be configured so as not to contain an acidic component. Colored pencil leads are often used in mechanical pencils and the like, so they often come into contact with metal materials. Therefore, by adopting a structure that does not contain an acidic component, it is possible to suppress corrosion of the metal portion of the mechanical pencil. Therefore, it is preferred that the colored pencil lead according to the invention does not contain acidic materials.

<Manufacturing method of colored pencil core>
The manufacturing method of the colored pencil lead according to the present invention is not particularly limited. however,
(a) a kneading step of kneading an extender and an inorganic binder to prepare a mixture;
(b) an extrusion step of extruding the mixture to form a linear form;
(c) a sintering step of sintering the linear molded product to create a porous substrate;
(d) an impregnation step of contacting and impregnating the porous substrate with a coloring agent solution containing a coloring agent and a high-boiling organic solvent having a boiling point of 250° C. or higher;
(e) a drying step of heating the porous substrate after the impregnation step at a temperature of 200° C. or less to form a porous core;
(f) A method comprising a filling step of contacting the porous core with a refractory liquid in which the coloring agent cannot be dissolved, and filling the pores of the porous core with the refractory liquid. It is preferably manufactured by This method will be described below.

(a) Kneading step First, the filler and the inorganic binder are kneaded to prepare a mixture. This mixture is the main component of the porous substrate. At the time of mixing, an organic solvent, a plasticizer, etc. can be added as required. The organic solvent used here is intended to give fluidity to the raw material mixture and to make the mixture uniform, and is almost completely removed in the firing process. Independent of organic solvents and refractory liquids.

(b) an extrusion step;
Subsequently, the formed mixture is extruded to form linear moldings. 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 extruded into a linear molded article.

(c) Firing Step The obtained linear shaped product is dried as necessary and then fired to form a porous base material. By firing, the organic solvent contained in the mixture is removed, and the filler and the inorganic binder are sintered to form a porous substrate. The sintering conditions are not particularly limited as long as the material is sintered to form a porous base material. Also, in order to avoid sudden temperature changes, the temperature during firing can be increased continuously or stepwise. The rate of temperature increase in such a case can be, for example, 10 to 100° C./hr. It is also preferable to bake at a constant temperature for a certain period of time, for example, about 0.5 to 2 hours after raising the temperature to the set temperature. Furthermore, each of these conditions can be arbitrarily combined according to 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 and fired. Conditions such as firing at 1000° C. for one hour can be employed.

(d) Impregnation step After cooling the formed porous substrate as necessary, the porous substrate is brought into contact with a solution containing a coloring agent and a high boiling point organic solvent. In this process, the pores present in the porous substrate are penetrated by the colorant solution. As a method for impregnation, normal pressure impregnation or reduced pressure/pressure impregnation can be used.

The colorant content of the colorant solution is not particularly limited, but the concentration of the colorant is preferably 5 to 50% by mass, more preferably 5 to 45% by mass, based on the total mass of the solution. , 10 to 40% by weight is particularly preferred. If the content is less than this range, the content of the coloring agent tends to be low, resulting in poor color development. The stability of the solution over time may decrease, such as the colorant precipitating over time. A surfactant may be added to the solution in order to improve the solubility and stability of the colorant.

Further, when a mixed solvent in which a high boiling point organic solvent is combined with a low boiling point organic solvent is used as a solvent for the colorant solution, the viscosity of the colorant solution is lowered to facilitate impregnation. It becomes easier to form voids in the pores. In this case, the pores of the core are easily impregnated with the refractory liquid, and the effect obtained by impregnating the wick with the refractory liquid can be sufficiently obtained. Such a low boiling point organic solvent is preferably a solvent that evaporates at 100° C. or lower, more preferably 90° C. or lower, and still more preferably 80° C. or lower. More preferably, aliphatic alcohols having 1 to 4 carbon atoms are preferred. The blending ratio of the high boiling point organic solvent and the low boiling point organic solvent can be adjusted according to the difference in boiling points and the solubility of the colorant. is preferably 1:1 to 1:15, more preferably 1:1 to 1:12, even more preferably 1:1.5 to 1:10, 1:1.5 ~1:7 is particularly preferred.

(e) Drying Step Subsequently, the porous substrate after the impregnation step is heated to remove part of the solvent contained in the solution impregnating the pores. As a result, the colorant and the high-boiling organic solvent remain in the pores and are adsorbed or adhered. Then, by heating, part of the solvent is removed, or the impregnation of the solvent into the porous base material progresses to form voids in the pores, thereby forming the porous core. Drying is carried out at a temperature of 200° C. or less, but can be carried out at a lower temperature, for example 100° C. or less, if the colorant solution contains a solvent with a relatively low boiling point. If the drying treatment can be performed at a low temperature, energy costs can be reduced, which is preferable.

(f) Filling Step After cooling the formed porous core as necessary, it is brought into contact with a refractory liquid. Through this process, the voids formed in the porous core are filled with the low-volatility liquid. The conditions at this time are not particularly limited, but, for example, a temperature of 60° C. for 6 to 12 hours can be employed. Normal pressure impregnation, reduced pressure, and pressure impregnation can be used to fill the refractory liquid.

If necessary, further washing and the like can be performed to obtain the colored pencil lead according to the present invention.

<Replacement lead cases and replacement lead products>
A refill lead product according to the present invention is obtained by housing the above-described colored pencil lead in a refill lead case. It is preferable that a resin material having a solubility parameter different from that of the refractory liquid by 1.5 or more is disposed on a portion of the inner surface of the refill lead case that can be contacted by the pencil lead. In order to protect the colored pencil lead, the refill lead case is made of a material with relatively high hardness, but is generally made of resin from the viewpoint of ease of manufacture and cost. However, if a suitable resin is not selected, the colored pencil lead and the resin material may adhere to each other.

According to the studies of the present inventors, such adhesion is suppressed when the difference between the SP value of the non-volatile liquid contained in the colored pencil lead and the SP value of the resin constituting the lead case is sufficiently large. found to be Such adhesion naturally occurs at the part of the refill case that comes into contact with the colored pencil lead, so the SP value of the resin placed in that part of the refill case is sufficiently different from the SP value of the refractory liquid. It is good if there is Specifically, the difference between the SP value of the refractory liquid and the SP value of the resin material disposed in the portion where the colored pencil lead contacts is preferably 1.5 or more, and the difference is 2.0 or more. is more preferable, a difference of 3.0 or more is more preferable, and a difference of 5.0 or more is even more preferable.

The difference between the SP value of the refractory liquid and the SP value of the resin material is preferably 1.5 or more, but either one may be larger. Also, the SP value of the refractory liquid and the SP value of the resin material are not particularly limited as long as these relative differences are satisfied. For example, when silicone oil with an SP value of 7.2 is used as the non-volatile liquid, the SP value of the resin material must be 5.7 or less, or 8.7 or more. Examples of resin materials that meet these conditions include polystyrene (8.6 to 9.7), vinyl acetate resin (9.4), vinyl chloride (9.5 to 9.7), and polycarbonate (9.7). ), polyacetal (11.1), acrylonitrile styrene resin (12.8), acrylonitrile-butadiene-styrene copolymer synthetic resin (12.1 to 15.0). In general, the SP value of resin materials tends to be higher than the SP value of refractory liquids. The SP value of the resin material is preferably 8.5-15.

In addition, it is preferable that the refill lead product according to the present invention allows the remaining amount of stored pencil lead to be visually recognized from the outside. Therefore, it is preferable to use a transparent resin material for the case. Therefore, it is preferable to use a resin having high toughness, excellent moldability, and transparency, and it is particularly preferable to use polycarbonate (9.7) or acrylonitrile styrene resin (12.8).

In the present invention, the shape of the extra lead case is not particularly limited, and any conventionally known shape can be adopted. For example, a replacement lead case is adopted that includes a storage portion that stores a colored pencil lead, and a lid portion that temporarily seals and deforms an opening provided in the storage portion so that the colored pencil lead can be taken out. can. Here, as the lid, any object generally called a lid can be adopted. Specifically, during transportation and storage, the opening provided in the storage unit is temporarily closed to hold the colored pencil lead in the replacement lead case, and when necessary, it can be removed, moved, or rotated. By deforming, it is possible to take out the colored pencil lead from the opening of the storage part.

As the simplest shape, as shown in FIG. 1, it is composed of a cylindrical housing portion 101 with one end closed and a lid portion 102 fitted into an opening formed at one end of the housing portion. A refill lead case can be exemplified. The colored pencil lead 103 housed in the replacement lead case can be taken out from the housing portion by removing the lid portion 102 from the housing portion 101 .

Here, in the refill lead product according to the present invention, a specific resin material is arranged in part of the part of the refill lead case that can come into contact with the colored pencil lead. In the refill lead case shown in FIG. 1, all the inner surfaces of the space defined by the inner surface of the accommodating portion and the bottom surface 102a of the lid after fitting come into contact with the colored pencil lead of the refill lead case. part that can be done. In the present invention, a specific resin material is arranged in a part of the part of the refill lead case that can come into contact with the colored pencil lead.

Here, the expression that a resin material is placed in a specific portion means, for example, forming that portion with a resin material, arranging a component formed of a resin material, or coating that portion with a resin material. do. For example, in the case of a refill lead case having a shape such as that shown in FIG. 1, this can be realized by forming the entire accommodating portion from a specific resin material. Of course, the lid portion may be made of a resin material, or the inner surface of the housing portion may be covered with a resin material.

In addition, in the present invention, if a specific resin material is disposed in part of the portion of the replacement lead case that can come into contact with the colored pencil lead, it is possible to prevent the colored pencil lead from adhering to the replacement lead case. However, it is preferable that the ratio of the area where the specific resin material is arranged to the total area of the portion where the colored pencil lead and the replacement lead case can come into contact is high. Specifically, the area of the portion where the specific resin material is disposed is preferably 50% or more, preferably 80% or more, of the total area of the portion of the refill lead case that can come into contact with the colored pencil lead. is more preferred, and 90% or more is particularly preferred. Ideally, it is preferable that a specific resin material be placed on all of the parts of the refill lead case that can come into contact with the colored pencil lead. Therefore, in the refill lead case of FIG. 1, although it depends on the size, by molding the accommodating portion with a resin material having a specific SP value, adhesion of the colored pencil lead can be suppressed.

Also, a refill lead case as shown in FIGS. 2 and 3 can be adopted. This is a replacement lead case in which a lid part 202 is detachably attached to a storage part 201 capable of storing a replacement lead. In this refill lead case, the lid portion 202 is formed with an engaging piece 202a protruding from the lower end, and the accommodating portion is formed with a recessed portion 201a that matches the engaging piece 202a. By forming in this way, when the engaging piece 202a of the lid is combined with the concave portion 201a of the housing portion, the protrusion and the concave portion are engaged with each other, and the lid portion is stably attached to the housing portion. can be installed. The protruding part and the recessed part can be exchanged and formed. In such a refill lead case as well, by forming the entire accommodating portion 201 using a specific resin material, adhesion of colored pencil leads can be suppressed. Also, the inner surface of the housing portion 201 may be coated with a specific resin material.

Also, a refill lead case as shown in FIGS. 4 and 5 can be adopted. This case is also a refill lead case in which a lid part 402 is detachably attached to a storage part 401 for storing colored pencil leads. The lid portion 402 is formed with an engagement piece 402a projecting from the lower end, and the housing portion 401 is formed with a concave portion 401a that matches the engagement piece 402a. When 402a is mated with recessed portion 401a of the receptacle, the protrusion and recessed portions can be engaged with each other to stably attach the lid to the receptacle. The protruding part and the recessed part can be exchanged and formed. In such a refill lead case as well, by forming the entire accommodating portion 401 using a specific resin material, adhesion of colored pencil leads can be suppressed.

Furthermore, a refill lead case as shown in FIGS. 6 and 7 can also be adopted. This case accommodates a colored pencil lead inside an accommodating portion 601 . By rotating the lid portion 602 around the rotating shaft 602D, the colored pencil lead can be held in the storage portion and the colored pencil lead can be taken out from the lead outlet 603. Specifically, the exit 603 for the colored pencil lead can be opened by turning the lid 602 upright, and the exit 603 can be closed by laying down the lid 602 . In this replacement lead case, a non-circular mounting hole 604E is formed in the lid portion fixing member 604, and a cut groove 604F is formed in the lid portion fixing member 604 crossing the mounting hole so that the mounting hole can be expanded. It is configured. In addition, an arcuate groove is formed in the lid portion fixing member on the side opposite to the outlet, and a rotating shaft 602D having a non-circular cross section is formed in the lid portion. The end on the rotating shaft side is formed in a semicircular shape, and the rim of the semicircular end is formed with a protruding portion having an appropriate width in the back direction from the front wall, and the rotating shaft of the lid portion It is rotatably attached to the attachment hole of the fixing member. Here, when the lid is laid down to close the outlet, the rotating shaft of the lid is engaged with the mounting hole of the lid fixing member, and the protuberance forms a notch crossing the mounting hole of the lid fixing member. It is designed to cover. When the lid is erected to open the outlet, the raised portion of the lid is brought into contact with the stopper portion of the arc-shaped cut groove of the lid fixing member to stop the rotation of the lid. . In such a replacement lead case as well, by forming the entire accommodating portion 601 using a specific resin material, adhesion of colored pencil lead can be suppressed.

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

[Production Example 101]
[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 a triple roll while water is evaporated, and the resulting kneaded product is extruded to a predetermined diameter. Molding was performed to obtain a linear molding. This linear molding was heated to 600°C at a rate of 10°C/hr in argon gas and held for 5 hours, then heated at 100°C/hr in an oxygen atmosphere and held at 900°C for 1 hour. After firing, a porous substrate with a porosity of 25% and a cross-sectional diameter of 0.55 mm was obtained.

[Impregnation process]
Coloring agent (blue dye) 30 parts by mass High boiling point organic solvent (phenyldiglycol) 10 parts by mass Low boiling point organic solvent (ethyl alcohol) 50 parts by mass
Resin (ketone resin) 10 parts by mass The above formulation was stirred at 30°C until uniformly mixed to obtain a colorant solution.

The porous base material obtained in the firing process was immersed in the coloring agent solution while being heated to 30°C, and held for 6 hours.

[Drying process]
After the impregnation step, the porous substrate was held at 80° C. for 6 hours to evaporate and remove the low boiling point organic solvent in the pores of the porous substrate to obtain a porous core.

[Filling process]
The porous core obtained in the drying step was immersed in silicone oil heated to 80° C. and held for 6 hours to obtain a colored pencil core. Next, excess silicone oil adhering to the surface of the colored pencil lead was removed by shaking off with a centrifuge to obtain a colored pencil lead of Example 101 impregnated with 12.5% by mass of silicone oil. Moreover, when this colored pencil lead was subjected to thermogravimetric measurement, it was confirmed that phenyldiglycol was contained. The content was 1% by mass or more.

[Examples 102 to 110, Comparative Examples 101 to 103]
A colored pencil lead was obtained in the same manner as in Example 101, except that each component was changed to those listed in Table 1. It was confirmed from thermogravimetry and production conditions that the colored pencil leads of Examples 102 to 110 and Comparative Example 102 contained a high-boiling organic solvent. Comparative Examples 102 and 103 were not filled with the hardly volatile liquid.
[evaluation]
The performance of the obtained colored pencil lead was evaluated by the following methods.

[Evaluation method for writing feel and handwriting color development]
High-quality paper (equivalent to writing paper A specified in the old JIS P3201) is prepared using colored pencil cores. Paper is made from 100% chemical pulp, and has a weighing range of 40 to 157 g/m ² and a whiteness of 75.0% or more. ), and the writing feeling at that time was evaluated by a sensory test (writing feeling 1). Also, the coloring property of the obtained handwriting (handwriting coloring property 1).
Furthermore, after production, using the baked colored pencil core left in an environment of 25 ° C. for 4 weeks, writing is performed on the high-quality paper, and the writing taste at that time (writing taste 2) and the color development of the handwriting obtained (handwriting color development 2). was evaluated by a sensory test.
(Evaluation criteria for writing taste 1 and 2)
A: Writing is possible very smoothly.
B: Smoothly writable.
C: Writing feeling is slightly rough and heavy.
D: Writing feeling is rough and heavy.
(Evaluation Criteria for Handwriting Color Development 1 and 2)
S: Very good color development.
A: Good color development.
B: Slightly inferior in color development, but good.
C: Inferior in color development.
D: Writing is possible, but color development is very poor.
E: Unable to write, no visible handwriting.

[Evaluation method for handwriting erasability]
The handwriting was erased according to the erasability test for plastic erasers disclosed in JIS S 6050-2008, and the erasability at that time was evaluated by a sensory test (erasability 1). In addition, after writing, using the writing line left for 4 weeks in a 25 ° C. environment, the handwriting was erased in accordance with the erasability test of the plastic eraser disclosed in JIS S 6050-2008. was evaluated by a sensory test (erasability 2). In addition, the existing product refers to a mechanical pencil lead "trade name: Neox Colorino (yellow)" manufactured by Pilot Corporation.
(Evaluation criteria for erasability 1 and 2)
A: Better than existing products.
B: Equivalent to existing products.
C: Not erasable.

In the table:
Blue dye B: Oil Blue 613 (manufactured by Orient Chemical Industry Co., Ltd.)
Red dye R: Spiron Red C-PH (manufactured by Hodogaya Chemical Industry Co., Ltd.)
Pink fluorescent pigment P: NKS1007 (manufactured by Nihon Shokuryo Kagaku Co., Ltd., a mixture of polyamide resin and C.I. Basic Violet 11:1)
Yellow fluorescent pigment Y: NKS1005 (manufactured by Nippon Shokuryo Kagaku Co., Ltd., a mixture of polyamide resin and C.I. Basic Yellow 40)
Surfactant: Neugen EA-137 (Daiichi Kogyo Seiyaku Co., Ltd.)
SO1: Dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-96-50cs. Surface tension: 20.8 N/m)
SO2: Methylphenyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-96-100cs)
[Examples 201 to 202, Comparative Example 201]
A colored pencil lead of each example was obtained in the same manner as in Production Example 101, except that each component was changed to that described in Table 2. It was confirmed from thermogravimetry and production conditions that the colored pencil lead of each example contained a high-boiling organic solvent. In addition, Comparative Example 201 was not filled with the hardly volatile liquid.

[Examples 201 to 202, Comparative Example 201]
The resulting colored pencil leads were accommodated in the replacement lead cases shown in FIG. 2 to obtain replacement lead products. The resin material used for the housing portion of this replacement lead case is as shown in Table 2, and 90% or more of the area of the portion of this replacement lead case that can come into contact with the colored pencil lead is composed of the resin material. .

[Evaluation method for colored pencil lead adhesion]
Each refill lead product was held at 50° C. for 14 days with the colored pencil lead in contact with the inner surface of the housing portion of the refill lead case, and the adhesion of the lead was evaluated according to the following criteria.

(Evaluation criteria for adhesion)
A: The colored pencil core does not adhere to the container at all. B: The colored pencil core adheres slightly to the container, but is easily peeled off. C: The colored pencil core adheres to the container.

[Evaluation method for writing feel and handwriting color development]
It was evaluated by the same evaluation method as in Example 101.

Blue dye B: Oil Blue 613 (manufactured by Orient Chemical Industry Co., Ltd.)
Pink fluorescent pigment P: NKS1007 (manufactured by Nihon Shokuryo Kagaku Co., Ltd., a mixture of polyamide resin and C.I. Basic Violet 11:1)
AS: acrylonitrile styrene resin (SP value 12.8)
PC: polycarbonate (SP value: 9.7)
SO1: Dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-96-50cs, SP value: 7.3, surface tension: 20.8 N / m)

101 Housing portion 102 Lid portion 102a Bottom surface 103 of lid portion 103 Colored pencil core 201 Housing portion 201a Engaging piece 202 Lid portion 202a Recessed portion 401 Recessed portion 401a Recessed portion 402 Lid portion 402a Engaging piece 601 Receiving portion 602 Lid portion 602D Rotating shaft 603 Outlet 604 Lid fixing member 604E Mounting hole

Claims (14)

1. body material and
   an inorganic binder;
   a coloring agent;
   a porous core containing a high-boiling organic solvent capable of dissolving the coloring agent and having a boiling point of 250° C. or higher;
   A colored pencil lead, wherein the coloring agent, the high-boiling organic solvent, and the low-volatility liquid are filled in the pores of the porous core.
2. The colored pencil lead according to claim 1, wherein the low-volatility liquid is selected from the group consisting of silicone oil, fluorinated oil, mineral oil, vegetable oil, and liquid paraffin.
3. The colored pencil lead according to claim 1 or 2, wherein the high-boiling organic solvent is an aromatic glycol ether or an aliphatic glycol ether.
4. The colored pencil lead according to any one of claims 1 to 3, wherein the content of the high boiling point organic solvent is 0.5 to 20% by mass based on the total mass of the colored pencil lead.
5. The colored pencil lead according to any one of claims 1 to 4, wherein the solubility of the coloring agent in the high-boiling organic solvent at 20°C is 10 g/100 g or more.
6. The colored pencil lead according to any one of claims 1 to 5, wherein the solubility of the coloring agent in the refractory liquid at 20°C is lower than the solubility of the coloring agent in the high-boiling organic solvent at 20°C.
7. The colored pencil lead according to any one of claims 1 to 6, wherein said extender is selected from the group consisting of titanium oxide, mica, talc, boron nitride, alumina, and calcium carbonate.
8. The inorganic binder is selected from the group consisting of clays, ceramics, zeolite, diatomaceous earth, activated clay, silica, aluminum phosphate, silicone resin, and silicone rubber, according to any one of claims 1 to 7 Colored pencil lead as described.
9. The colored pencil lead according to any one of claims 1 to 8, wherein the porous core has a porosity of 1 to 50%.
10. The colored pencil lead according to any one of claims 1 to 9, wherein the porous core is a fired core.
11. (a) a kneading step of kneading an extender and an inorganic binder to prepare a mixture;
    (b) an extrusion step of extruding the mixture to form a linear form;
    (c) a sintering step of sintering the linear molded product to create a porous substrate;
    (d) an impregnation step of contacting and impregnating the porous substrate with a coloring agent solution containing a coloring agent and a high-boiling organic solvent having a boiling point of 250° C. or higher;
    (e) a drying step of heating the porous substrate after the impregnation step at a temperature of 200° C. or less to form a porous core;
    (f) A filling step of contacting the porous core with a refractory liquid in which the colorant cannot be dissolved, and filling the voids of the porous core with the refractory liquid. A method for manufacturing a colored pencil lead, characterized by:
12. The method according to claim 11, wherein the colorant solution further comprises a low-boiling organic solvent having a boiling point of less than 250°C.
13. A replacement lead product comprising the colored pencil lead according to any one of claims 1 to 10 and a replacement lead case containing it.
14. A resin material having a solubility parameter different from the solubility parameter of the refractory liquid by 1.5 or more is arranged on a part of the inner surface of the replacement lead case that can be contacted by the colored pencil lead. The refill product according to claim 13.

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