JP2009029906A - Solid drawing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple and inexpensive solid drawing material, which can draw lines of various thicknesses and depths, and be treated in the same manner as a lead close to a perfect circle. <P>SOLUTION: The solid drawing material has a deformed outer circumferential section, the outer circumferential section having R/P of 1-200, wherein R is the circumscribed core diameter of the solid drawing material, and P is the circularity by least square center method. The solid drawing material has a spirally twisted shape in the sectional direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid drawing material that can be suitably used mainly for a pencil lead for a mechanical pencil, a pencil lead for a wooden shaft, and the like.

  In a pencil lead which is a solid drawing material, important properties generally required include mechanical strength and line drawing density. For this reason, with a thin core, when the drawn line density is increased, the mechanical strength becomes weak, and sufficient strength against the writing load cannot be ensured.

As a pencil lead satisfying these conflicting properties, for example, a fired pencil lead that can be highly oriented by molding graphite at a high pressure to increase bending strength and bending elastic modulus and a method for producing the same are known. (For example, see Patent Document 1 by the present applicant).
According to this pencil lead, the strength of the pencil lead itself has increased and the writing quality per wear has improved, but there is a slight problem in that the writing quality becomes worse when wear is reduced. Currently.

  On the other hand, as a pencil lead that tried to solve the above problem from a completely different viewpoint, for example, a thin strand was formed by mixing and bonding a carbon material and a binder and other required additives, and several of these strands were combined. A pencil lead (for example, see Patent Document 2) formed by bonding with a material is known.

  However, when the technique of the above-mentioned Patent Document 2 is used, there is a possibility that the wire portion becomes irregular as in the present invention and the structure is fixed with a covering member. However, Patent Document 2 originally has an irregular outer peripheral portion. Therefore, since it is not the purpose to write a thin drawn line, the spiral structure is neither described nor suggested as in the present invention.

  In addition, as a weak point of a solid writing instrument including a pencil lead, there is a problem that the fixing property of the drawn line is low and the paper surface and hands become dirty when the drawn drawn line is rubbed.

As a pencil lead that solves the above problem, a pencil lead (for example, see Patent Document 3) in which an adhesive is impregnated in the pencil lead is known. In this invention, in order to increase the content of the adhesive, the porosity is set to 15 to 60%.
However, since the strength decreases when the porosity of the pencil lead is set large, it is difficult to increase the fixing force while maintaining a certain level of strength.

Furthermore, there is an element called a core diameter in the types of conventional pencil cores for mechanical pencils. As a feature, a core with a large core diameter has a smooth writing strength and high strength, but a drawn line is thick, and a core with a thin core diameter can draw a drawn line thinly, but the writing quality is poor and is easy to break. As a result, a diameter of 0.5 mm is used as a standard in terms of balance of strength, writing quality, and drawn line thickness.
Normally, there is only one type of core diameter that can be used with one mechanical pencil, and as a result, 0.5 mm in diameter is common even with mechanical pencils, so a thin core with a diameter of 0.3 mm or 0.4 mm, etc. Mechanical pencils with a diameter of 0.3 mm or 0.4 mm are not common even if there is a demand for the diameter, so in order to obtain a fine line, there was annoyance such as having to purchase a dedicated holder .
JP-A-8-53642 (Patent No. 3205184, Claims, Examples, etc.) JP-A-57-57696 (Claims, Examples, etc.) Japanese Patent Publication No. 5-10397 (Claims, Examples, etc.)

  The present invention is a further improvement of the above prior art in view of the current state of the art and problems, and can draw drawn lines that can change various thicknesses, writing styles, drawn line stability, and the like. An object is to provide an inexpensive solid drawing material.

  As a result of intensive studies to solve the above-described conventional problems, etc., the present inventor, as a solid drawing material having an irregular outer peripheral cross section, by setting the outer cross section of the solid drawing material to a specific structure, etc. The inventors have found that a solid drawing material for the above purpose can be obtained, and have completed the present invention.

That is, the present invention resides in the following (1) to (6).
(1) A solid drawing material having an irregular outer peripheral cross section, where R / P is 1 to 200, where R is a core diameter that circumscribes the solid drawing material, and P is a roundness in the least square center method. A solid drawing material having a certain outer peripheral cross section and spiraling in a cross-sectional direction.
(2) The solid drawing material according to the above (1), wherein the solid drawing material is a mechanical pencil lead composed of at least graphite and binder carbon.
(3) The solid drawing material according to (1) or (2) above, wherein a helical pitch in the solid drawing material is 0.5 to 20 mm.
(4) The solid drawing material according to any one of (1) to (3), wherein an outer wear surface of the solid drawing material is coated with an easily wearable material.
(5) The solid drawing material according to (4), wherein the easily wearable material in the solid drawing material is at least one selected from waxes, fats, resins, ceramics, and carbon materials.
(6) The solid drawing material according to any one of the above (1) to (5), wherein the easily wearable material has a thickness of 0.05 to 0.5 mm.
The “spiral” defined in the present invention means a deformation that appears when the upper end of a straight core is fixed and a couple of forces is applied to the lower end to rotate it by a certain angle.

According to the present invention, it is possible to draw drawn lines of various thicknesses and darknesses, and can be handled in the same manner as a core close to a perfect circle, and a simple and inexpensive solid drawing material can be obtained.
Moreover, the solid drawing material excellent also in mechanical strength (bending strength, tensile strength, compressive strength) can be obtained by covering the outer peripheral surface of the solid drawing material with an easily wearable material.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The solid drawing material of the present invention is a solid drawing material having an irregular outer peripheral cross section. When the outer diameter of the solid drawing material is R and the roundness in the least squares center method is P, R / P is 1. It has an outer peripheral cross section of ˜200 and spirals in the cross sectional direction.

FIG. 1 is a perspective view showing an example of an embodiment in which the solid drawing material of the present invention is applied to a pencil lead.
As shown in FIG. 1, the pencil lead A in the present embodiment has an equilateral triangular outer cross section, the outer diameter of the pencil lead is R, and in this embodiment, R is 0.565, which is the minimum. When the roundness in the square center method is P, it has an outer peripheral cross section where R / P is 4, and spirals in the cross-sectional direction (vertical direction).

The pencil lead A of the above embodiment has an outer peripheral cross section of a regular triangle (R / P = 4). In the present invention, R / P varies depending on the shape of the pencil lead, but it needs to be in the range of 1 to 200, preferably 1 in terms of line thickness, strength and writing feeling. .4-50 is desirable.
If this value R / P is less than 1, the thinnest part is too thin and the core becomes a brittle core as a whole. On the other hand, if it exceeds 200, a normal cylindrical core and an unchanged core become undesirable.

  Moreover, in the pencil lead A of this embodiment, the helical pitch pi is 5 mm. In the present invention, the helical pitch varies depending on the shape type of the pencil lead, but from the point of balance between gripping force when gripping with a chuck, feeding stability and stability when writing, 0.5 to 20 mm, Preferably, the thickness is 3 to 10 mm.

2A and 2B and FIGS. 3A and 3B show the pencil leads B to D, respectively.
The core B in FIG. 2 (a) is a “kushi noodle” -shaped core, and the cross section has a shape with a core of φ0.29 mm extending to a circumscribed core diameter of φ0.565 mm. The degree is 0.28 μm and the helical pitch is 5 mm.
The core C in FIG. 2B has an isosceles triangle shape in cross section, and the helical pitch is 5 mm.
The core D in FIG. 3A has a square cross section and a helical pitch of 5 mm.
The core E in FIG. 3B has a shape in which three cores having a diameter of 0.263 mm are bundled and twisted.

  These pencil cores can be made from a blended composition containing at least an extender and a shaping material. As the extender, for example, graphite conventionally used for fired cores, amorphous carbon (amorphous carbon) serving as binder carbon, boron nitride, etc. can be used, and sinterable (sintered) boron nitride. If it sinters at high temperature, it will not be specifically limited but can be used. Specifically, cubic boron nitride, hexagonal boron nitride, etc. can be used, and naturally, a mixture of these graphite, amorphous carbon (amorphous carbon), boron nitride, sintered boron nitride, etc. can also be used. It is. By using sinterable boron nitride for part or all of the extender, the mechanical strength such as bending strength is further improved without impairing the smooth writing quality.

  Examples of the shaping material include organic shaping materials such as thermoplastic resins such as vinyl chloride resin, chlorinated vinyl chloride resin, and polyvinyl alcohol, thermosetting resins such as furan resin, phenol resin, and epoxy resin, Pitches such as natural polymer substances such as lignin, cellulose and tragacanth gum, petroleum asphalt, coal tar pitch, naphtha decomposition pitch, and dry distillation pitch of synthetic resin can be used, and naturally several kinds of these mixtures can also be used.

Furthermore, water (purified water), dioctyl phthalate (DOP), dibutyl phthalate (DBP), tricresyl phosphate (TCP), adipine are used for the purpose of improving the characteristics during kneading performed by applying high shear force and improving the characteristics of extrusion molding. You may mix | blend the plasticizer of an organic shaping material, such as dioctyl acid (DOA), propylene carbonate, alcohols, ketones, esters, or 2 types or more as needed.
In addition, talc, kaolin, montmorillonite, sericite, mica, mica titanium, alumina, silica fine particles, titanium oxide, zinc oxide, zeolite, pyrophyllite, calcium carbide, barium sulfate from the viewpoint of further improvement in mechanical strength. In addition, ceramics such as halloysite can be contained.

  These blended compositions are sufficiently kneaded with a Henschel mixer, a pressure kneader, two rolls, etc., then extruded with a die having a cross-sectional shape, a single screw extruder, etc. It is fixed by spiraling so that Next, in order to fix the spiral while removing the remaining plastic material from these, after heat treatment in air, it is further fired in a non-oxidizing atmosphere such as a nitrogen atmosphere or an inert gas atmosphere such as argon gas. Thus, a fired core body can be obtained and impregnated with an α-olefin oligomer or the like to produce a spiral fired pencil core having various shapes. Further, it is also effective to form while being spiraled by a spinning extruder or the like at the time of extrusion molding.

In the fired core, a white fired core may be formed using boron nitride or the like instead of graphite, and the white fired core may be impregnated with ink to form a colored pencil core. By impregnating with ink, a pencil lead having a changed appearance can be obtained.
As the ink to be impregnated, any conventionally known color pencil lead can be used. For example, colorants such as dyes and pigments are produced by dissolving and dispersing in animal and vegetable oils, synthetic oils, alcohols, hydrocarbon oils, water, etc., or adding resins, surfactants, etc. as necessary. Commonly used printing inks, stamp inks, ballpoint pen inks, water-based writing inks, and the like are used. Further, this white fired core may be immersed in ink and impregnated with ink under conditions such as heating, decompression, and pressurization. Furthermore, you may perform the said immersion operation etc. repeatedly.
Furthermore, in the present invention, the obtained core is further improved in terms of smoothness, such as mineral oil such as engine oil, synthetic oil such as α-olefin oligomer, silicone oil, ester oil, castor oil, etc. It may contain lubricating oil such as vegetable oil.

In the above embodiment, the outer peripheral surface of the spiral-fired pencil core having each cross-sectional shape is coated with an easily wearable material so as to be close to a circular cross-sectional shape, thereby being excellent in mechanical strength (bending strength, tensile strength, compressive strength). It is good also as a solid drawing material.
Examples of easy-wear materials that can be used include waxes such as paraffin wax and castor wax, oils and fats such as castor oil, oleic acid and lard, resins such as low density polyethylene, CMC and ethyl cellulose, boron nitride, talc, kaolin, Examples thereof include at least one selected from ceramics such as sericite, and carbon materials such as graphite and amorphous carbon.
As a coating method, for example, the outer peripheral surface of a spiral-fired pencil lead having a cross-sectional shape is coated with a solution obtained by mixing and dispersing the above easy-wear material with a heating mixer or the like by dip coating, spray coating, shot coating, or the like. be able to.
The film thickness of the easily wearable material is preferably 0.05 to 0.5 mm, more preferably 0.05 to 0.2 mm from the viewpoint of strength, core diameter, writing quality, and concentration.

  The size of the solid drawing material of the present invention varies depending on uses such as a pencil lead for a mechanical pencil, a pencil lead for a wooden shaft, and a full lead pencil lead. For example, a pencil lead for a mechanical pencil has a diameter of 0. .375-1.3 mm, with a wooden core pencil lead having a diameter of 1.3-4 mm, and for a full lead, having a diameter of 4.0-20 mm.

In the present invention configured as described above, it is possible to draw drawn lines of various thicknesses and darknesses, and can be handled in the same manner as a core close to a perfect circle, and a simple and inexpensive solid drawing material can be obtained. .
In particular, by adjusting the cross-sectional shape, the thickness of the drawn line, the writing quality, the drawn line stability, and the like can be changed. In addition, since the gap is larger than that of a cylindrical core, it is possible to add value to fixability, erasability, strength, writing quality, and the like.
Furthermore, a solid drawing material excellent in mechanical strength (bending strength, tensile strength, compressive strength) can be obtained by coating the outer peripheral surface of the solid drawing material with an easily wearable material. In addition, the core diameter (diagonal length) is a spiral-fired pencil core of various shapes such as 0.3 mm and 0.4 mm, and the outer peripheral surface is coated with an easy-wear material and a 0.5 mm mechanical pencil with a circular cross section. If you use a pencil lead, etc., you can easily draw writing lines with a variety of core diameters of 0.3 mm and 0.4 mm using a general-purpose 0.5 mm mechanical pencil without using a dedicated holder. Will be able to.

  Next, the present invention will be further described with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
Natural graphite (average particle size 7μm) 40% by weight
42% by weight of vinyl chloride resin
Dioctyl phthalate 16% by weight
Oleic acid amide 2% by weight
The above blended composition was dispersed and mixed with a Henschel mixer, kneaded with a pressure kneader and two rolls, then set at an extrusion temperature of 100 ° C. with a screw type extruder, and extruded with a square cross section. The core was fixed by spiraling at a spiral pitch of 4.0 mm. In order to fix the spiral while removing the remaining plastic material from these, after heat treatment at 200 ° C. for 10 hours in air, the temperature was raised to 1000 ° C. in a nitrogen atmosphere and baked at 1000 ° C. for 1 hour. A fired core was obtained. This was impregnated with an α-olefin oligomer to obtain a helically fired pencil lead having a square cross section with a diagonal length of 0.57 mm as shown in FIG.

(Example 2)
A cross-sectional square with a diagonal length of 0.57 mm as in Example 1, except that the same composition as in Example 1 above was used and the spiral core was formed continuously by using a spinning extruder as the molding machine. A shaped spiral fired pencil lead was obtained.

(Example 3)
FIG. 5 is the same as in Example 1 except that the same composition as in Example 1 above is used, a thin die is formed using a circular die, and the three are immediately bundled and spiraled at an arbitrary spiral pitch. A spirally-fired pencil lead having a three-spinning substantially circular shape of 0.57 mm was obtained.

Example 4
The three-spinned, substantially circular 0.57 mm spirally fired pencil core of Example 3 is dip-coated with phenol resin (Resitop PL-2211 manufactured by Gunei Chemical Industry Co., Ltd.) and cured at 300 ° C. in a nitrogen atmosphere. After that, the α-olefin oligomer was impregnated again to obtain a spiral fired pencil lead having a substantially circular shape of 0.57 mm.

(Example 5)
Low-density polyethylene 30 parts by weight Paraffin wax 70 parts by weight The above materials were mixed and dispersed with a heating mixer for 1 hour to obtain Solution A.
The substantially circular 0.57 mm spiral fired pencil lead of Example 3 was dip coated with the solution A to obtain a substantially circular 0.57 mm spiral fired pencil lead.

(Example 6)
As shown in FIG. 6, the same composition as in Example 1 is used, except that it is formed into a thin line using an elliptical die and immediately spiraled at an arbitrary spiral pitch. A spiral fired pencil lead having a substantially circular shape of 0.57 mm was obtained.

(Example 7)
As shown in FIG. 7 as in Example 1, except that the same composition as in Example 1 above is used, a thin wire is formed using a substantially triangular die, and then immediately spiraled at an arbitrary spiral pitch. A substantially circular 0.57 mm spirally fired pencil lead was obtained.

(Example 8)
Using the same composition and manufacturing method as in Example 2 above, only a helical pitch of 0.5 mm and a diagonal length of 0.57 mm were obtained.

Example 9
Using the same composition and manufacturing method as in Example 2 above, only a helical pitch was set to 20 mm, and a square-shaped spiral fired pencil lead having a diagonal length of 0.57 mm was obtained.

(Example 10)
Using the same composition and production method as in Example 3, a spiral fired pencil lead having a square cross section with a diagonal length of 0.57 mm with only a helical pitch of 0.5 mm was obtained.

(Example 11)
Boron nitride (average particle size 6 μm) 39% by weight
43% by weight of vinyl chloride resin
Dioctyl phthalate 16% by weight
Oleic acid amide 1% by weight
Nanoceria (average particle size 10μm) 1% by weight
The above blended composition was dispersed and mixed with a Henschel mixer, kneaded with a pressure kneader and two rolls, then set at an extrusion temperature of 100 ° C. with a screw type extruder, and extruded with a square cross section. The core was fixed by spiraling at an arbitrary spiral pitch. In order to remove the remaining plastic material from these, after heat-treating in air at 180 ° C. for 10 hours, the temperature was raised to 1000 ° C. in a nitrogen atmosphere and baked at 1000 ° C. for 1 hour. Next, it heat-fired at 700 degreeC in air | atmosphere, the carbonized material was removed, and the white core was obtained. 100 g of this core is immersed in a container containing 150 g of a xylene solution of perhydropolysilazane (20% by weight) and then fired in nitrogen gas at 1200 ° C. for 1 hour, and the cross-sectional visual shape spiral white fired core with a diagonal length of 0.57 mm Got the body. Further, the core was immersed in red ink and left at 70 ° C. for 24 hours. The surface of the fired core body filled with this ink was washed to obtain a spiral red fired pencil lead having a square cross section with a diameter of 0.57 mm.

(Comparative Example 1)
For mechanical pencils having a diameter of 0.57 mm, drying and firing were performed under the same conditions as in Example 1, except that the die shape was made circular using the same composition as in Example 1 above. I got a wick.

(Comparative Example 2)
For mechanical pencils having a diameter of 0.47 mm, drying and firing were performed under the same conditions as in Example 1 except that the die shape was made circular using the same composition as in Example 1 above. I got a wick.

(Comparative Example 3)
For mechanical pencils having a diameter of 0.37 mm, drying and firing were performed under the same conditions as in Example 1 except that the die shape was made circular using the same formulation as in Example 1 above. I got a wick.

(Comparative Example 4)
For mechanical pencils with a diameter of 0.27 mm, drying and firing were performed under the same conditions as in Example 1 except that the die shape was made circular using the same composition as in Example 1 above. I got a wick.

(Comparative Example 5)
A mechanical pencil lead having a diagonal length of 0.57 mm was obtained in the same manner as in Example 1 except that the spiral was not formed after the above Example 1 and extrusion molding.

(Comparative Example 6)
A mechanical pencil lead having a diagonal length of 0.57 mm was obtained in the same manner as in Example 1 except that Example 6 was not spiraled after extrusion.

(Comparative Example 7)
A mechanical pencil lead having a diagonal length of 0.57 mm was obtained in the same manner as in Example 1 except that Example 7 was not used and the spiral was not formed after extrusion.

(Comparative Example 8)
Using the same formulation as in Example 11, a mechanical pencil lead having a diagonal length of 0.57 mm was obtained in the same manner as in Example 11 except that the spiral was not formed after extrusion.

(Comparative Example 9)
For mechanical pencils having a diameter of 0.57 mm, drying and firing were performed under the same conditions as in Example 11 except that the die shape was made circular using the same composition as in Example 11 above. I got a wick.

(Comparative Example 10)
A substantially circular meter spiral firing with a diagonal length of 0.57 mm in the same manner as in Example 1 except that the die shape was changed to an ellipse of R / P = 2.8 using the same composition as in Example 11 above. I got a pencil lead.

About each pencil lead, pencil lead for mechanical pencils, etc. obtained in Examples 1 to 11 and Comparative Examples 1 to 10, R / P, spiral pitch, bending strength of pencil lead, vertical load, wear, etc. Each evaluation of the amount, concentration, drawn line thickness, and sensory evaluation (drawn line fineness, smoothness, ease of breakage, and stain resistance) was performed.
These results are shown in Table 1 below.

(R / P measurement method)
Each pencil lead and pencil lead for mechanical pencil are observed with a scanning electron microscope (SEM) at a magnification of 150 times, and a circle with the smallest sum of squares of deviation is calculated for the obtained shape. The circumscribed circle and the inscribed circle were read and calculated.

(Measuring method of spiral pitch)
The cross-sectional shape of the core was measured by averaging the length of one rotation.

(Measurement method of bending strength)
The bending strength of the pencil core was measured by a three-point bending test using Tensilon (ORIENTEC RTC-1150A) in a strength test (40 mm between fulcrums, 20 mm / min) specified in JIS S 6005-2000 (n = 100). .

(Measurement method of vertical load)
Each core was fed and gripped by M5-552 manufactured by Mitsubishi Pencil Co., Ltd., and the load that caused the core slip when a load was applied vertically with the pen body fixed was measured with Tensilon (ORIENTEC RTC-1150A).

(Wear test method)
In the concentration test specified in JIS S 6005-2000 (however, writing angle 75 °, load 300 gf, writing distance 6 m), the change amount (mm) of the wear length of the core when writing was measured (n = 10). ).

(Measurement method of concentration)
It is the value which measured the drawn line of the pencil lead written in the density | concentration test prescribed | regulated to JISS6005-2000 with the densitometer (sakura DENSIMETER PDA65) (n = 10x4 places).

(Measurement method of stroke thickness)
The pencil line drawn by the density test specified in JIS S 6005-2000 (writing angle 75 °, load 300 gf, Kent paper, writing distance 6 m) was measured with a microscope.

(Evaluation method for line fineness, smoothness, ease of breakage, and ease of contamination)
We asked 10 monitors to write the word “Kai” on 500-character manuscript paper and evaluated it according to the following criteria.
The fineness of the drawn line is evaluated by 1 to 5 (the higher the numerical value, the thinner the drawn line) when Comparative Example 1 is set to “1” in a five-step evaluation.
The smoothness is evaluated by 1 to 5 (the higher the numerical value, the higher the smoothness) of the writing quality when Comparative Example 1 is set to “1” in a five-step evaluation.
The ease of folding is the average number of times of folding.
There are four levels of stain resistance. [◎: paper surface is not dirty at all, ○: paper surface is hardly dirty, Δ: dirty as much as normal 0.4-HB, ×: normal It stains as much as 0.5-HB].

  As is clear from the results in Table 1 above, the multilayer cores 1 to 13 within the scope of the present invention are compared with Comparative Examples 1 to 6 outside the scope of the present invention in terms of bending strength, wear amount, concentration, dynamic friction. It was found that the coefficient, the thickness of the drawn line, and the sensory evaluation (drawn line fineness, smoothness, avoidance of breakage, and stain resistance) were excellent.

  In the present invention, drawn lines of various thicknesses and densities can be drawn, and the mechanical strength is strong, and at the same time, drawn lines can be obtained without soiling the hand, so it is suitable for pencil pencils for mechanical pencils, wooden axes, etc. Can be used.

It is a perspective view of the pencil lead used as the solid drawing material which shows an example of embodiment of this invention. (A) And (b) is a perspective view which shows each other embodiment of a pencil lead. (A) And (b) is a perspective view which shows each other embodiment of a pencil lead. The electron micrograph figure of the cross-sectional aspect of the pencil lead of Example 1 is shown. (A) And (b) shows the electron microscope photograph figure of the side surface and cross-sectional aspect of the pencil lead of Example 3. The electron micrograph figure of the cross-sectional aspect of the pencil lead of Example 6 is shown. The electron micrograph figure of the cross-sectional aspect of the pencil lead of Example 7 is shown.

Claims (6)

  A solid drawing material having an irregular outer peripheral cross section, wherein R / P is 1 to 200, where R is a core diameter that circumscribes the solid drawing material and P is a roundness in the least square center method. And a solid drawing material that spirals in the cross-sectional direction.   The solid drawing material according to claim 1, wherein the solid drawing material is a mechanical pencil lead composed of at least graphite and binder carbon.   The solid drawing material according to claim 1, wherein a helical pitch in the solid drawing material is 0.5 to 20 mm.   The solid drawing material according to claim 1, wherein an easily wearable material is coated on an outer peripheral surface of the solid drawing material.   The solid drawing material according to claim 4, wherein the easy-wear material in the solid drawing material is at least one selected from waxes, oils and fats, resins, ceramics, and carbon materials.   The solid drawing material according to any one of claims 1 to 5, wherein the easily wearable material has a thickness of 0.05 to 0.5 mm.