Solid drawing material

Abstract

To provide a solid drawing material which has high colorability, is hardly broken and has good writing feeling.SOLUTION: The solid drawing material comprises a pigment, a wax, a molding resin, a lubricant and an inorganic filler. The inorganic filler has an aspect ratio of 2:1 or less, and the content ratio of the inorganic filler to the solid drawing material is 35 mass% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a solid drawing material. [Background technology]

[0002] Solid drawing materials are known that are not wrapped in paper and can be held in the hand for use without soiling the fingers. For example, Patent Document 1 discloses a solid drawing material that contains at least a pigment, a polar thermoplastic resin, a non-polar thermoplastic resin, a wax, and a monoglyceride of a glycerin fatty acid ester having a melting point of 35°C or higher. The solid drawing material of Patent Document 1 is obtained by blending a polar thermoplastic resin and a non-polar thermoplastic resin to form a sea-island structure of resins, resulting in a solid drawing material with good fixation and high drawing density.

[0003] Patent Document 2 discloses a hard solid drawing material containing a pigment, at least one molding resin selected from polyethylene and polypropylene, a first wax, a second wax made of a polypropylene-based polymer obtained using a metallocene catalyst, and a lubricant. Patent Document 2 discloses that a solid drawing material that is hard yet has high colorability can be obtained by using two specific types of wax in combination. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-316608 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-252134 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, there is a need for improved coloring properties for solid drawing materials that can be held in the hand and used as is without the need for wrapper paper or the like. At the same time, there is a need for solid drawing materials that are strong enough to not break even without wrapper paper or a protective material, and that have a smooth writing feel. One of the objects of the present invention is to provide a solid drawing material that has high coloring properties, is resistant to breaking, and has a good writing feel. [Means for solving the problem]

[0006] The solid drawing material according to the present disclosure includes a pigment, a wax, a molding resin, a lubricant, and an inorganic filler, the inorganic filler having an aspect ratio of 2:1 or less, and a content of the inorganic filler relative to the solid drawing material of 35% by mass or less. [Effects of the Invention]

[0007] The solid drawing material having the above-mentioned constitution has high coloring properties, is resistant to breakage, and provides a good writing feel. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a method for evaluating the breaking strength of a solid drawing material. [Figure 2] FIG. 2 is a scanning electron microscope image of the inorganic filler used in the solid drawing material of the example. [Figure 3] FIG. 3 is a scanning electron microscope image of the inorganic filler used in the solid drawing material of the comparative example. [Figure 4] FIG. 4 is a scanning electron microscope image of the inorganic filler used in the solid drawing material of the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] First, embodiments of the solid drawing material according to the present disclosure will be described. The solid drawing material according to the present disclosure includes a pigment, a wax, a molding resin, a lubricant, and an inorganic filler. The inorganic filler has an aspect ratio of 2:1 or less, and the content of the inorganic filler relative to the solid drawing material is 35% by mass or less.

[0010] Hard solid drawing materials that can be held in the hand and used for drawing have been known. These hard solid drawing materials contain pigments, molding resins, waxes, and, if necessary, lubricants, oils, etc. Hard solid drawing materials with better coloring properties are desired. Coloring properties are achieved when the drawing material disintegrates appropriately in response to pen pressure and the disintegrated material adheres to the surface of the drawing material, such as drawing paper. Hard solid drawing materials contain molding resins to maintain their shape. It was thought that the molding resins make the solid drawing materials hard and difficult to scrape, impairing coloring properties. Based on this, studies were conducted to improve coloring properties while maintaining hardness.

[0011] The solid drawing material according to the present disclosure contains an inorganic filler, and the inorganic filler has an aspect ratio of 2:1 or less. The inorganic filler content relative to the solid drawing material is 35% by mass or less. These configurations allow the solid drawing material to maintain its resistance to breakage while using less molding resin than conventional materials, and to obtain a solid drawing material with high colorability. Without being bound by any particular theory, it is believed that by using a particulate inorganic filler with a low aspect ratio as the inorganic filler, the inorganic filler normally fills the microstructure of the solid drawing material, maintaining the strength of the structure. When writing, the amount of molding resin is small, so the solid drawing material crumbles all at once, allowing more of the coloring component to adhere to the drawing surface.

[0012] In the solid drawing material, the total content of the inorganic filler and the molding resin relative to the solid drawing material may be 20% by mass or more and 50% by mass or less, which more reliably achieves the effects of the present disclosure, such as break resistance, excellent colorability, and a good drawing feel.

[0013] In the solid drawing material, the molding resin may be a polyethylene resin or a polypropylene resin. When the molding resin is a polyethylene resin or a polypropylene resin, the content of the molding resin in the solid drawing material can be reduced while maintaining hardness.

[0014] In the solid drawing material, the inorganic filler may have a cubic or plate-like shape and may not be in the form of an aggregate. By using inorganic fillers in these forms, the effects of the present disclosure can be reliably obtained.

[0015] Hereinafter, embodiments of the solid drawing material according to the present disclosure will be described in more detail. In the following description, unless otherwise noted, the expression "A to B" means "A or more, B or less."

[0016] (Solid drawing material) The external shape of the solid drawing material according to the present disclosure is not particularly limited. The shape of the solid drawing material may be cylindrical, polygonal prism such as a triangular prism or a quadrangular prism, or an elliptical cylinder with an elliptical cross section. It is also preferable that one end of the cylinder is tapered to form a pointed tip. The shape of the solid drawing material according to the present disclosure is not limited to a columnar (rod) shape, but may also be a block or lump shape such as a rectangular parallelepiped. The dimensions, length, diameter, and overall size of the solid drawing material can be determined arbitrarily depending on the application, desired ease of use, etc. As an example, the solid drawing material is preferably cylindrical with a diameter of 5 mm to 12 mm and a length of approximately 60 to 130 mm.

[0017] The solid drawing material according to the present disclosure may be provided to a user without a wrapper or protective sheet, and may be used by holding the main body of the solid drawing material directly in the hand. A protective sheet made of paper or film may be wrapped around the body of the solid drawing material.

[0018] (Composition of solid drawing materials) The solid drawing material of the embodiment described below is a hard solid drawing material also known as a plastic crayon. The solid drawing material according to the present disclosure contains a pigment, a wax, a molding resin, a lubricant, and further contains an inorganic filler. The components constituting the solid drawing material according to the present disclosure are described below.

[0019] (pigment) Pigments (colored pigments) impart a desired color (achromatic or chromatic) to solid drawing materials, causing the color to appear on the drawing surface. Pigments that have traditionally been used as colorants in hard solid drawing materials, crayons, and oil pastels can be used. Examples of pigments include organic pigments, inorganic pigments, lake pigments, composite pigments, fluorescent pigments, pearl pigments, and luster pigments, and any one or more of these can be used. Examples of pigments include, but are not limited to, white pigments such as titanium oxide and zinc sulfide, colored pigments such as phthalocyanine and quinacridone, and carbon black.

[0020] Specific examples of colored pigments include organic pigments, inorganic pigments, and metal powder pigments such as titanium oxide, zinc oxide, carbon black, iron black, aniline black, Hansa Yellow, benzidine yellow, tartrazine lake, permanent yellow toner, cadmium yellow, benzidine orange, chrome vermilion, cadmium orange, permanent orange GTR, fast orange lake, lake red C, red iron oxide, watching red, brilliant carmine 6B, permanent red F5R, permanent red 2B, permanent red FRLL, carmine lake, quinacridone red, methyl violet lake, fast violet B, quinacridone violet, indanthrene violet, ultramarine blue, phthalocyanine blue, fast sky blue, iron blue, ultramarine blue, Victoria blue lake, phthalocyanine green, marker light green lake, pigment green B, viridian, sienna, umber, aluminum powder, and bronze powder.

[0021] The amount of pigment to be added may be selected appropriately depending on the desired color. For example, the pigment may be contained in the range of 1 to 30% by mass of the solid drawing material, and preferably in the range of 1 to 20% by mass. If the pigment content is 30% by mass or less, the solid drawing material will have little loss of smoothness and good writing properties. If the pigment content is 1% by mass or more, the desired color can be obtained, although this will depend on the material.

[0022] (wax) The wax may be a component primarily composed of organic compounds that is solid at room temperature and melts when heated. It is preferable to use a wax that exhibits minimal change in strength with temperature. The wax is used to bind the various components that make up the solid drawing material together and to provide the solid drawing material with adhesion to the drawing surface. The melting point of the wax used in the solid drawing material according to the present disclosure is not particularly limited, but is, for example, 50°C or higher, preferably 55°C or higher.

[0023] Examples of waxes that can be used include animal-derived waxes such as beeswax, spermaceti, beef tallow, hardened beef tallow oil, and lard; plant-derived waxes such as carnauba wax, Japan wax, hardened castor oil, and hardened palm oil; and petroleum-derived waxes such as paraffin wax, Fischer-Tropsch wax, polyethylene wax, α-olefins, long-chain fatty acids, long-chain fatty acid esters, long-chain fatty acid amides, and ketone waxes containing long-chain aliphatic ketones. One or more waxes can be used in combination. Among these, paraffin wax and microcrystalline wax are preferred. It is also preferred to use a combination of multiple waxes with different melting points. For example, it is preferred to use a paraffin wax and a microcrystalline wax in combination. When using a combination of waxes, it is also preferred to use a wax with a melting point of approximately 50°C in combination with a wax with a melting point of approximately 85°C.

[0024] The wax content may be in the range of 10 to 60% by mass, preferably 20 to 50% by mass, and more preferably 30 to 45% by mass, of the solid painting material. If the wax content is 60% by mass or less, the color will not fade and color development will be maintained. If the wax content is 10% by mass or more, the strength and moldability of the solid painting material will be maintained, and adhesion to the painting surface will be obtained.

[0025] (molding resin) The molding resin is used to impart strength to the solid drawing material so that the drawing material formed into a thin rod shape can be held in the hand for drawing. Thermoplastic resins can be used as the molding resin, and specific examples include polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, acrylic resin, and polyvinyl acetate resin. Among these, it is preferable to use at least one molding resin selected from polyethylene resin and polypropylene resin. More preferably, polyethylene resin is used as the molding resin. The molding resin contained in the solid drawing material is more preferably polyethylene resin. The polyethylene resin may be low-density polyethylene resin or high-density polyethylene resin. More specifically, polyethylene resins having a melting point of about 100°C to 115°C and a specific gravity (density) of 0.91 to 0.93 g / cm are preferred. 3 A low density polyethylene resin may be used.

[0026] The molding resin exists as plate-like crystals in the structure of the solid drawing material, and is thought to form the skeleton of a house-of-cards structure that surrounds the colorant and oil. The solid drawing material according to the present disclosure can maintain sufficient strength by combining it with an inorganic filler having a specific shape, even if the content of the molding resin is lower than conventional ones (for example, the content of the molding resin is 25% by mass or less).

[0027] The amount of molding resin blended is not limited as long as the effects of the present disclosure are obtained, but may be in the range of 10 to 40% by mass, preferably 10 to 35% by mass, of the solid drawing material. If the molding resin is 40% by mass or less, there is little loss of coloring power and a good writing feel can be maintained. If the molding resin is 10% by mass or more, good breaking strength can be obtained as a hard solid drawing material, and a solid drawing material that does not stick to the hands can be formed.

[0028] (lubricant) Lubricants are components that impart lubricity to solid drawing materials and contribute to improving the writing feel. Metal salts of higher fatty acids can be used as lubricants. Specific examples include alkali metal salts and alkaline earth metal salts of higher fatty acids having 12 to 20 carbon atoms, such as myristic acid, palmitic acid, and stearic acid. More specific examples include metal stearates such as calcium stearate, aluminum stearate, barium stearate, lithium stearate, magnesium stearate, and sodium stearate.

[0029] The amount of lubricant blended is not limited as long as the effects of the present disclosure are obtained, but may be in the range of 5 to 30% by mass, preferably 5 to 20% by mass, of the solid drawing material. If the lubricant content is 30% by mass or less, there is little loss of coloring power and a good writing feel can be maintained. If the lubricant content is 5% by mass or more, the effect of improving the writing feel becomes clear.

[0030] (oil) The solid drawing material according to the present disclosure may contain oil. Oil is a component that is liquid at room temperature and is primarily composed of organic compounds. Oil cooperates with wax to give the solid drawing material smooth drawing properties. Transparent oils that are compatible with wax are preferably used. Specific examples of oils that can be used include animal and vegetable oils such as coconut oil and castor oil, and petroleum-derived oils such as liquid paraffin, spindle oil, silicone oil, and long-chain fatty acids. One type of oil can be used, or two or more types of oils can be used in combination. Of these, liquid paraffin is preferably used.

[0031] The amount of oil may be in the range of 1 to 10% by mass of the solid drawing material, and preferably in the range of 1 to 5% by mass. If the oil content is 10% by mass or less, the strength of the solid drawing material is maintained, there is little reduction in heat resistance, and the solid drawing material is less likely to stick to the hands. If the oil content is 1% by mass or more, the solid drawing material will have better slipperiness and can have the effect of improving adhesion to the drawing surface. Oil is not an essential component, and the solid drawing material may not contain oil.

[0032] (inorganic filler) The solid drawing material according to the present disclosure contains an inorganic filler with an aspect ratio of 2:1 or less. It has been discovered that by using an inorganic filler with an aspect ratio of 2:1 or less, a hard solid drawing material with high strength can be obtained even with a low molding resin content. The aspect ratio of the inorganic filler is a value measured by the following method.

[0033] The method for measuring the aspect ratio of an inorganic filler will be described below. First, the inorganic filler contained in the solid drawing material is extracted. The method for extracting the inorganic filler is not particularly limited, but for example, the solid drawing material is heated to decompose the organic matter, and the inorganic filler is obtained by separating, washing, and drying the residual components. Images of the extracted inorganic filler are taken using a scanning electron microscope (e.g., JSM-LT100, manufactured by JEOL Ltd.). From the obtained image, 30 inorganic filler particles are randomly selected, and the major axis length and minor axis length of each particle are measured. The number of particles measured is not limited to 30, and can be more or less than 30, as long as stable measurement results are obtained. For example, the major axis length and minor axis length of 100 inorganic filler particles can be measured. If the particles are irregular in shape, the smallest rectangle enclosing the particles is imagined, and the lengths of the long and short sides of that rectangle are measured. The length of the long side of the rectangle is the major axis, and the length of the short side is the minor axis, and the ratio of the major axis to the minor axis is calculated, and the average value is used as the measured aspect ratio. If the aspect ratio is listed in the inorganic filler catalog, you can refer to that.

[0034] When the inorganic filler is cubic, the aspect ratio is approximately 1:1. The inorganic filler used in the solid painting material according to the present disclosure is preferably cubic or plate-shaped, and is preferably not an aggregate. "Not an aggregate" means that the inorganic filler particles are not secondary particles formed by agglomeration of fine primary particles, but are composed of inseparable primary particles. The inorganic filler used in the solid painting material is preferably not a spindle-shaped or needle-shaped particle with a high aspect ratio (for example, an aspect ratio of 2.8:1 or more).

[0035] Specific examples of inorganic fillers that can be used include, for example, one or a combination of two or more of carbonates such as magnesium carbonate and calcium carbonate; sulfates such as calcium sulfate and barium sulfate; silicate compounds such as aluminum silicate, hydrous silica, and anhydrous silica; and clay minerals such as talc, clay, kaolin, and bentonite. Of these, calcium carbonate and magnesium carbonate are preferred. It is essential that the inorganic filler have an aspect ratio of 2:1 or less, and the composition is not limited as long as the effects of the present disclosure can be obtained.

[0036] The inorganic filler may be contained in an amount ranging from 10 to 35% by mass, preferably from 10 to 30% by mass, based on the solid drawing material. If the inorganic filler is 35% by mass or less, the strength of the solid drawing material is maintained by the effect of combination with the molding resin, improving colorability, and suppressing color development (white blur) of the solid drawing material. If the inorganic filler is 10% by mass or more, the effect of improving colorability is obtained and the effect of reducing the amount of molding resin can be obtained.

[0037] The solid drawing material according to the present disclosure has a lower content of molding resin than conventional solid drawing materials, while maintaining the same strength and improving colorability. The total content of inorganic filler and molding resin in the solid drawing material is not particularly limited, but may be 20% to 50% by mass, and preferably 30% to 40% by mass. When the total content is within this range, it is easy to create a solid drawing material with good color development and writing feel by appropriately blending it with other components such as wax and pigments. Furthermore, the amount of molding resin used can be reduced.

[0038] (Other ingredients) The solid pigmentation material according to the present disclosure may contain various components and additives used in conventional solid pigmentation materials, as needed. Examples of additives include antiseptics, antifungals, and antioxidants. When antioxidants are contained, examples of the antioxidants include dibutylhydroxytoluene, propyl gallate, tocopherol, butylhydroxyanisole, and nordihydroguaiaretic acid. These may be used alone or in combination.

[0039] (Manufacturing method) A manufacturing method for a solid drawing material will now be outlined. The solid drawing material according to the present disclosure can be manufactured by applying or adapting existing equipment and conditions without deviating from known manufacturing methods for solid drawing materials. The manufacturing method shown below is one example, and the manufacturing method is not limited as long as a solid drawing material having the effects according to the present disclosure can be obtained.

[0040] First, in the kneaded composition preparation process, wax, molding resin, lubricant, and oil are heated and stirred, and dispersed using, for example, a kneader. The device used for dispersion is not particularly limited as long as it is capable of heating and stirring materials, and known heating and stirring devices such as kneaders and mixers can be used. Next, pigments, inorganic fillers, and other materials are added to the resulting mixture, and the mixture is stirred while heated to obtain a kneaded composition. The resulting kneaded composition is cooled and pulverized into pellets. These pellets are molded (e.g., by injection molding or extrusion molding) to obtain a molded product of the desired shape, i.e., the solid drawing material according to the present disclosure. In addition to these processes, cutting, adjusting, measuring, inspecting, and other processes may be included to adjust the shape to the desired one.

[0041] [Examples and Comparative Examples] Solid drawing materials of Examples 1 to 6 and Comparative Examples 1 to 7, which are solid drawing materials with different compositions, were prepared. The blending ratios of the solid drawing materials of Examples 1 to 6 are shown in Table 1. The blending ratios of the solid drawing materials of Comparative Examples 1 to 7 are shown in Table 2. A blank space in each table indicates that the material was not included. The numerical values ​​in each table are in parts by mass.

[0042] [Table 1]

[0043] [Table 2]

[0044] The methods for producing the solid drawing materials of Examples 1 to 6 and Comparative Examples 1 to 7 will be described in detail below.

[0045] [Example 1] 1. Wax (paraffin wax (melting point 58.5°C) and microcrystalline wax (melting point 60-85°C)), molding resin (polyethylene, PE-LF640H, manufactured by Japan Polyethylene Corporation), lubricant (calcium stearate, SC-P, manufactured by Sakai Chemical Industry Co., Ltd.), oil (liquid paraffin, white mineral oil, manufactured by Sanko Chemical Industry Co., Ltd., specific gravity 0.861 g / mL, viscosity 41.4 m 2 The mixture was dissolved in water and stirred with a mixer. 2. Pigments (Pigment Blue 15 (Dainichiseika Color & Chemicals Mfg. Co., Ltd.) and titanium oxide (TCA-888, Sakai Chemical Industry Co., Ltd.)) and inorganic filler (calcium carbonate (aspect ratio 1.1:1), Brilliant 1500, Shiraishi Calcium Co., Ltd.) were added, and the mixture was further heated and stirred. 3. The composition was cooled, crushed and pelletized. 4. The pellets were melted under heating and poured into a cylindrical molding container, then cooled and solidified to obtain a rod-shaped solid painting material with a diameter of 8 mm and a length of 62 mm. In steps 1 and 2, the materials were added in the proportions shown in Table 1.

[0046] [Example 2] A solid drawing material was prepared in the same manner as in Example 1, except that the blending ratio of the materials was set to the blending ratio shown in Table 1.

[0047] [Example 3] A solid painting material was prepared in the same manner as in Example 1, except that calcium carbonate (aspect ratio 1.3:1, Hakuenka 0, manufactured by Shiraishi Calcium Co., Ltd.) was used as the inorganic filler.

[0048] [Example 4] A solid painting material was prepared in the same manner as in Example 1, except that calcium carbonate (aspect ratio 2.0:1, Homocal D, manufactured by Shiraishi Calcium Co., Ltd.) was used as the inorganic filler. Figure 2 shows a scanning electron microscope image of the inorganic filler used in Example 4. The image shown in Figure 2 is taken from the product catalog.

[0049] [Example 5] A solid drawing material was prepared in the same manner as in Example 4, except that the blending ratio of the materials was set to the blending ratio shown in Table 1.

[0050] [Example 6] A solid drawing material was prepared in the same manner as in Example 1, except that talc (aspect ratio 1.1:1, Nanoace D-600, manufactured by Nippon Talc Co., Ltd.) was used as the inorganic filler.

[0051] [Comparative Example 1] A solid drawing material was prepared in the same manner as in Example 1, except that no inorganic filler was used and the blending ratios shown in Table 2 were used.

[0052] Comparative Example 2 A solid drawing material was prepared in the same manner as in Example 4, except that the blending ratio of the materials was as shown in Table 2.

[0053] Comparative Example 3 A solid painting material was prepared in the same manner as in Example 1, except that calcium carbonate (aspect ratio 5.0:1, Silver W, manufactured by Shiraishi Calcium Co., Ltd.) was used as the inorganic filler.

[0054] Comparative Example 4 A solid drawing material was prepared in the same manner as in Example 1, except that calcium carbonate (aspect ratio 2.9:1, light calcium carbonate, manufactured by Ohmi Chemical Industry Co., Ltd.) was used as the inorganic filler. [Fig. 3] shows a scanning electron microscope image of the inorganic filler used in Comparative Example 4.

[0055] Comparative Example 5 A solid painting material was prepared in the same manner as in Example 1, except that calcium carbonate (aspect ratio 2.8:1, PC-700, manufactured by Shiraishi Calcium Co., Ltd.) was used as the inorganic filler.

[0056] Comparative Example 6 A solid drawing material was prepared in the same manner as in Example 1, except that calcium carbonate (aspect ratio 13.9:1, Whiscal A, manufactured by Maruo Calcium Co., Ltd.) was used as the inorganic filler. [Fig. 4] shows a scanning electron microscope image of the inorganic filler used in Comparative Example 6.

[0057] Comparative Example 7 A solid drawing material was prepared in the same manner as in Example 1, except that talc (aspect ratio 16:1, wollastonite, manufactured by Nippon Talc Co., Ltd.) was used as the inorganic filler.

[0058] [evaluation] The solid drawing materials of Examples 1 to 6 and Comparative Examples 1 to 7 were evaluated for coloring amount, amount of residue, breaking strength, and writing feel by the following methods.

[0059] (1) Evaluation of coloring amount Using a drawing tester, the solid drawing material was applied to drawing paper under the following conditions. Speed ​​2.9mm / s Width: 42mm Distance: 53 round trips Load: 700g The amount of coloration and the amount of residue were calculated using the following formulas. Amount of colorant (mg) = Weight of drawing paper after application - Weight of drawing paper before application After measuring the amount of coloring, the coated surface was brushed with a brush to remove any residue that had not adhered to the coated surface, and the weight was measured again. Amount of residue (mg) = Weight of drawing paper after application - Weight of drawing paper after removing residue

[0060] (2) Evaluation of breakage strength The solid drawing material was left in a constant temperature bath at 37±2°C for one hour. After one hour had passed, the solid drawing material 1 was supported on two supports as shown in Figure 1, and using a push-pull testing machine, it was pushed at a speed of 10 mm / s using a jig 10 with a 5R tip, and the load (kg) at breakage was measured. The distance between the supports W1 was 40 mm. The bending strength test was conducted in accordance with JIS S 6026.

[0061] (3) Evaluation of writing feel The feel of the solid drawing material when applied to drawing paper was evaluated. The evaluation criteria for the writing feel were as follows: ○: Smooth writing feel ×: Dry writing feel

[0062] The evaluation results of the solid drawing materials of Examples 1 to 6 are shown in Table 3. The evaluation results of the solid drawing materials of Comparative Examples 1 to 7 are shown in Table 4.

[0063] [Table 3]

[0064] [Table 4]

[0065] As shown in Table 3, the solid drawing materials of Examples 1 to 6 all had significantly more than twice the amount of coloring as the example not containing inorganic filler (Comparative Example 1). Furthermore, the amount of residue was 2.8 mg or less. The breaking strength was the same as the example not containing inorganic filler (Comparative Example 1). Furthermore, the writing feel was good.

[0066] As shown in Table 4, Comparative Example 1, which did not contain an inorganic filler, had a small amount of coloring. Comparative Example 2, which contained 40% by mass of inorganic filler, had low breaking strength, which was thought to be because the inorganic filler was too large and made the sheet more susceptible to breaking. Comparative Example 3, in which an inorganic filler with an aspect ratio of 5.0:1 was used as the inorganic filler, had low breaking strength. Comparative Example 4, in which an inorganic filler with an aspect ratio of 2.9:1 was used as the inorganic filler, had low breaking strength and a dry writing feel. Comparative Example 5, in which an inorganic filler with an aspect ratio of 2.8:1 was used as the inorganic filler, also had low breaking strength and a dry writing feel. Comparative Example 6, which used an inorganic filler with an aspect ratio of 13.9:1, had a high coloring amount but a large amount of residue, and although the strength was improved, the writing feel was rough. In Comparative Example 7, in which needle-shaped inorganic filler particles with an aspect ratio of 16:1 were used as the inorganic filler, the writing feel was rough although the strength was improved.

[0067] It should be understood that the embodiments and examples disclosed herein are illustrative in all respects and are not limiting in any respect. The scope of the present invention is defined not by the above description but by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0068] 1 solid drawing material, 10 jigs

Claims

1. A pigment, Wax and A molding resin; A lubricant; Inorganic filler and A solid drawing material comprising: The inorganic filler has an aspect ratio of 2:1 or less, and the content of the inorganic filler relative to the solid drawing material is 35% by mass or less. Solid drawing material.

2. the total content of the inorganic filler and the molding resin relative to the solid drawing material is 20% by mass or more and 50% by mass or less; The solid drawing material according to claim 1 .

3. The molding resin is a polyethylene resin or a polypropylene resin. The solid drawing material according to claim 1 or 2.

4. The inorganic filler has a cubic or plate-like shape and is not an aggregate. The solid drawing material according to claim 1 or 2.

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