JP7138435B2 - Solid cursive and solid cursive set using the same - Google Patents

Description

The present invention relates to solid cursive writing. Further, it relates to a solid writing body capable of forming high density handwriting and a solid writing body set using the same.

Conventionally, non-fired solid writing materials using coloring materials have been put to practical use in the form of colored pencils covered with a wooden shaft or the like. In order to impart strength to the core and obtain sufficient handwriting density, it is necessary to layer the handwriting by overcoating. At that time, the strength was maintained by applying dibasic acid derivatives and polymethacrylic acid esters, etc., because the smoothness at the time of writing was insufficient and it was difficult to layer on the handwriting that was written earlier. Techniques for imparting smoothness are applied (see Patent Documents 1 and 2, for example).

When the technology is applied to a solid writing material using a reversible thermochromic composition that can alternately store and retain the state before and after discoloration in a certain temperature range such as a normal temperature range as a coloring material, as in Patent Document 3. , Since the handwriting density is lower than that of general-purpose coloring materials, recoating may be repeated in order to obtain a sufficient handwriting color density. At that time, repeated re-coating at high speed generates frictional heat, which causes thermal decoloration, which may result in faint handwriting or discoloration.

JP 2015-209506 A JP-A-11-61026 Japanese Utility Model Laid-Open No. 7-6248

The present invention provides a solid writing material that has sufficient core strength even if it is a non-baked solid writing material, provides a smooth writing feeling during writing, is easy to be laminated on the previously written handwriting, and has excellent recoating properties. It provides cursive writing.
In addition, even when a thermochromic microcapsule pigment containing a reversible thermochromic composition is used as a coloring material, there is no color loss or color change due to frictional heat during recoating, and the amount of layered handwriting To provide a solid writing material capable of forming shading by using ink and forming high-concentration handwriting.

The solid writing material according to the present invention comprises (a) an electron-donating color-developing organic compound, (b) an electron-accepting compound, and (c) a reaction medium for controlling the color reaction of (a) and (b). A microcapsule pigment containing a reversible thermochromic composition encapsulated in microcapsules, an excipient, a filler, a binder resin, and a weight average molecular weight of 200,000 or less and ASTM D 1238: 230 ° C., load 2 and a polypropylene having a melt flow rate (MFR) of 50 to 2500 g/10 min measured at .16 kg, and the content of said polypropylene is 5% by weight or less in the total weight.
Furthermore, it is required that the softening point of the polypropylene is in the range of 80 to 125°C.
Furthermore, it is required to further include a friction member.
Furthermore, a solid longhand set comprising any of the above solid longhand bodies and a friction body is required.

According to the present invention, even a non-baked solid writing material has sufficient core strength, a smooth writing feeling is obtained during writing, and it is easy to be laminated on the previously written handwriting, and it is excellent in recoating properties. It becomes a thing. Therefore, it is possible to write or paint with a smooth writing feeling without breaking under high writing pressure, and it is possible to easily improve the density of handwriting and form shades by overcoating.
In addition, even when a thermochromic microcapsule pigment is used as a coloring material, it does not cause discoloration or color change due to frictional heat during recoating, and the formation of shades depending on the amount of layering of handwriting and high concentration. It becomes a solid cursive material that allows handwriting formation.

The solid longhand according to the present invention includes a core material component containing at least a coloring agent, an excipient, a filler, and a binder resin, and in addition, polypropylene having a weight average molecular weight of 200,000 or less is used in an amount of 5% by mass or less. It is characterized by In particular, when a thermochromic microcapsule pigment encapsulating a reversible thermochromic composition consisting of components (a), (b), and (c) is applied as a coloring material, unprecedented effects can be imparted. becomes better.

Examples of coloring materials used in the present invention include azo organic pigments such as disazo yellow AAA and pyrazolone orange; cyanine organic pigments such as phthalocyanine blue and phthalocyanine green; high-grade organic pigments such as quinacridone red; , fluorescent pigments, carbon black, iron black, red iron oxide, Prussian blue, rutile, inorganic pigments such as titanium dioxide such as atanase, and dyes.
In addition, in the present invention, since it is difficult to generate frictional heat even when recoating is performed at high speed, it is possible to use a coloring material that changes color due to frictional heat, such as a thermochromic pigment.

The coloring material that changes color due to frictional heat is selected regardless of whether it is reversible or irreversible, if the handwriting changes color (hue change, transparency, or color disappearance) when the handwriting is rubbed with a friction body or the like and heated. can be applied In addition to the coloring agent itself that changes hue, it is also possible to use a transparent (decoloring) coloring agent together with a general-purpose coloring agent to change the hue.
Examples of coloring materials that discolor by heating include reversible types disclosed in JP-A-2012-219160 and JP-A-2014-5422, and irreversible types disclosed in JP-A-2010-229332. is applicable.
In particular, by encapsulating the thermochromic composition in microcapsules, the change in handwriting can be achieved stably for a long period of time without causing a change in composition, which is suitable. As the thermochromic composition encapsulated in the microcapsules, from the viewpoint of repeated usability, accuracy of temperature change, etc., (a) an electron-donating color-developing organic compound, (b) an electron-accepting compound, (c) A reversible thermochromic composition comprising a reaction medium that determines the temperature at which the two color reactions occur is preferred.

The reversible thermochromic composition comprising the components (a), (b) and (c) is described in JP-B-51-44706, JP-B-51-44707, JP-B-1-29398, etc. The color changes before and after a predetermined temperature (color change point) as a boundary, exhibits a decoloring state in a temperature range above the high temperature side color change point, and a color development state in a temperature range below the low temperature side color change point. Of these, only one specific state exists in the normal temperature range, and the other state is maintained while the heat or cold required to express that state is applied, but the application of the heat or cold Reversible thermochromic compositions having a relatively small hysteresis width (ΔH = 1 to 7 ° C.), which returns to the state exhibited in the normal temperature range when the temperature disappears, are heat-discolored by encapsulating them in microcapsules. type microcapsule pigments can be applied.
Furthermore, relatively large hysteresis characteristics (ΔH = 8 to 50 ° C.), and exhibits large hysteresis characteristics described in JP-A-2006-137886, JP-A-2006-188660, JP-A-2008-45062, JP-A-2008-280523, etc. That is, the shape of the curve plotting the change in color density due to temperature change is greatly different when the temperature is increased from the lower temperature side than the discoloration temperature range and when the temperature is decreased from the higher temperature side than the discoloration temperature range. A reversible thermochromic composition that changes color along a path and retains color in a specific temperature range in a colored state in a low temperature range below the complete color development temperature or in a colorless state in a high temperature range above the complete color disappearance temperature. A heat-erasable microcapsule pigment containing is also applicable.
Specifically, the reversible thermochromic composition having a color memory that is applied to the present invention is a temperature at which the complete coloring temperature can be obtained only in a freezer, a cold region, or the like, that is, -50 to 0 ° C. , preferably -40 to -5 ° C., more preferably -30 to -10 ° C., and the temperature obtained from a familiar heating body such as a frictional heat by a friction body, a hair dryer, that is, 50 to 95 ° C. , preferably 50 to 90 ° C., more preferably 60 to 80 ° C., and specifying the ΔH value to 40 to 100 ° C., effectively maintaining the color exhibited in the normal state (daily life temperature range) can function.

Microencapsulation of the thermochromic composition includes interfacial polymerization method, interfacial polycondensation method, in situ polymerization method, in-liquid curing coating method, phase separation method from aqueous solution, phase separation method from organic solvent, melting dispersion cooling method, aerial suspension coating method, spray drying method, etc., which are appropriately selected according to the application. Furthermore, depending on the purpose, the surface of the microcapsule pigment may be further provided with a secondary resin film to impart durability, or the surface characteristics may be modified for practical use.
The microcapsule pigment has an average particle diameter of 0.01 to 8.0 μm, preferably 0.1 to 5.0 μm, more preferably 0.3 to 3.0 μm, in terms of writing performance and handwriting density. It is suitable from
In addition, the average particle diameter is obtained by determining the particle region using the image analysis type particle size distribution measurement software "MacView" manufactured by Mountec, and calculating the projected area circle equivalent diameter (Heywood diameter) from the area of the particle region. , is the value measured as the average particle diameter of particles equivalent to a sphere of equal volume based on that value. In addition, when the particle diameter of all or most of the particles exceeds 0.2 μm, a particle size distribution measuring device (manufactured by Beckman Coulter Co., Ltd., product name: Multisizer 4e) is used to measure equivolumetric spheres by the Coulter method. It is also possible to measure the average particle size as the average particle size of the particles of.

Various additives such as antioxidants, ultraviolet absorbers, infrared absorbers, solubilizers, preservatives and antifungal agents can be added to the microcapsule pigments as long as they do not affect their functions. In addition, by blending a non-thermochromic coloring material such as a dye or a pigment, it is also possible to adopt a configuration in which a color change between colored (1) and colored (2) occurs.

The content of these coloring materials is preferably 40% or less of the total weight of the solid longhand, from the viewpoint of the balance between coloring properties, writing feel and strength. In addition, the content of the coloring material varies depending on the use of wooden shafts, mechanical pencils, etc., and ranges from very light colors to dark colors. , may exceed 40%, and is adjusted as appropriate within a range that does not impair the effects of the present invention.

Examples of excipients that can be used include waxes, gelling agents, and clays. As the wax, any conventionally known wax may be used, and specific examples include carnauba wax, Japan wax, beeswax, microcrystalline wax, montan wax, candelilla wax, sucrose fatty acid ester, and dextrin fatty acid ester. , polyolefin wax, styrene-modified polyolefin wax, and paraffin wax. Conventionally known gelling agents can be used, such as 12-hydroxystearic acid, dibenzylidene sorbitols, tribenzylidene sorbitols, amino acid oils, alkali metal salts of higher fatty acids, and the like. Clay minerals include kaolin, bentonite, montmorillonite, and the like.
Among the excipients, it is particularly preferable to contain at least one of polyolefin wax, sucrose fatty acid ester and dextrin fatty acid ester. Specific polyolefin waxes include waxes of polyethylene, polypropylene, polybutylene, α-olefin polymers, ethylene-propylene copolymers, ethylene-butene copolymers, and the like.

In particular, among the polyolefin waxes, those having a softening point in the range of 100° C. to 130° C. and a penetration of 10 or less are preferably used because of their excellent writing feel. If the penetration exceeds 10, the solid writing material is too soft and tends to be difficult to write on. It stains blank areas on the surface, and causes color transfer and stains on other paper.
The method for measuring the softening point and penetration of the polyolefin wax is standardized in JIS K2207, and a value of 0.1 mm is represented as 1 penetration. Therefore, the smaller the number, the harder the solid writing, and the larger the number, the softer the solid writing.

Specifically, Neowax series (polyethylene manufactured by Yasuhara Chemical Co., Ltd.), Sanwax series (polyethylene manufactured by Sanyo Chemical Industries, Ltd.), Hiwax series (polyolefin manufactured by Mitsui Chemicals, Inc.), AC polyethylene (Honeywell manufactured by Polyethylene) and the like.

The mixing ratio of the excipient is preferably 0.2 to 70% by mass with respect to the total mass of the solid writing material. If the thickness is less than this range, it tends to be difficult to obtain a writable shape as a core material, and if it exceeds this range, it tends to be difficult to obtain sufficient writing density. Preferably, it is 0.5 to 40% by mass, and within this range, both the shape of the solid writing and the handwriting density can be achieved.

The filler is blended for the purpose of improving the strength of the solid writing material and adjusting the writing feel. Examples of fillers applied in the present invention include talc, clay, silica, calcium carbonate, barium sulfate, alumina, mica, boron nitride, potassium titanate, and glass flakes. In particular, talc and calcium carbonate are preferable from the viewpoint of moldability and influence on discoloration performance when microcapsule pigments are used.

The blending ratio of the filler is preferably 10 to 65% by mass with respect to the total mass of the solid longhand. If the thickness is less than this range, the strength tends to decrease.

The binder resin is blended for the purpose of improving the strength of the solid writing material, and natural resins and synthetic resins can be used. Specific examples include olefin-based resins, cellulose-based resins, vinyl alcohol-based resins, pyrrolidone-based resins, acrylic-based resins, styrene resins, amide-based resins, and basic group-containing resins. In particular, ethylene-vinyl acetate copolymer resin, ethylene-vinyl alcohol copolymer resin, and polyvinyl alcohol resin are suitable because molding stability is improved by combined use with polyester polyol resin.
The amount of the binder resin to be added is preferably in the range of 0.5 to 5% by mass based on the total amount of the solid longhand.

Further, in the solid writing material of the present invention, a low molecular weight polypropylene having a weight average molecular weight of 200,000 or less is used, and added in an amount of 5% by mass or less based on the total mass of the solid writing material.
The low molecular weight polypropylene has a weight average molecular weight (Mw) of 200,000 or less, preferably 5,000 or more, as determined by gel permeation chromatography (GPC method). Among them, those having a molecular weight distribution (Mw/Mn: measured by GPC method) of 4 or less are most excellent in recoating properties.
The production method is not particularly limited, but metallocene catalysts, Ziegler type polymerization catalysts, other transition metal compounds, organic boron compounds, and aluminoxane are polymerized by known methods using polymerization catalysts, high molecular weight polypropylene is pyrolyzed or Any substance that is oxidatively decomposed to have a low molecular weight, or a by-product that is separated by solvent extraction or the like in the production of high-molecular-weight polypropylene can be targeted. In addition, acid groups of α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid and itaconic acid or their anhydrides are introduced into the molecule by post-treatment. good too.

Among the above polypropylenes, those having a softening point in the range of 80 to 125° C. are particularly useful because they have a good performance balance when forming a solid writing object in terms of moldability, strength, and disintegration.

The melt flow rate (MFR) of the polypropylene is not particularly limited, but the MFR (ASTM D 1238: measured at 230 ° C. and a load of 2.16 kg) is 40 to 3000 g / 10 min, preferably 50 to 2500 g / 10 min. A range applies. If the MFR is less than 40 g/10 min, the melt viscosity is high during molding and the productivity is lowered. On the other hand, if it exceeds 3000 g/10 min, the melt viscosity will decrease and molding will become difficult.

Examples of the low-molecular-weight polypropylene include L-MODU series manufactured by Idemitsu Kosan Co., Ltd., Licocene PP series manufactured by Clariant Co., Ltd., Viscole series manufactured by Sanyo Chemical Co., Ltd., and the like.

The polypropylene having a weight-average molecular weight of 200,000 or less is added in an amount of 5% by mass or less, preferably 0.1% by mass or more, relative to the total mass of the solid longhand. If the amount exceeds 5% by mass, the hardness of the solid writing material becomes high, which impairs recoating properties, making it difficult to obtain high-concentration handwriting.

In addition, various additives can be added as necessary. Additives include viscosity modifiers, antifungal agents, preservatives, antibacterial agents, UV inhibitors, antioxidants, lubricants, fragrances, and the like.

The solid writing material according to the present invention can be used alone as a writing material, or can be used as an inner core and provided with an outer shell covering its outer peripheral surface (double core). Such an outer shell prevents the solid writing material inside from being damaged by physical contact, and also contributes to the improvement of the mechanical strength of the whole solid writing material. Such an outer shell may or may not contain a coloring agent that contributes to handwriting formation. often have no effect. For this reason, it is common not to add colorants to the outer shell.
Various additives can be added to the outer shell as necessary for the purpose of imparting various functions. Additives include colorants, antifungal agents, preservatives, antibacterial agents, ultraviolet absorbers, antioxidants, lubricants, perfumes, and the like. Any of these additives can be used.

As a manufacturing method of the solid longhand, it can manufacture using extrusion molding and compression molding. As a specific example of the core-sheath structure, a solid body provided with an outer shell covering the outer peripheral surface of the inner core is formed by arranging the outer shell on the outer peripheral surface of the inner core mass and compressing it with a press. You can get cursive.

Incidentally, the thickness and length of the solid cursive can be arbitrarily selected according to the purpose. For example, when considering the case of using the solid writing material according to the present invention as a pencil lead, the thickness is generally 2.0 to 5.0 mm, preferably 2.5 to 4.0 mm. The height is generally 60-300 mm, preferably 80-200 mm.
In the case of a core-sheath structure, the thickness of the inner core and the thickness of the outer shell can be arbitrarily selected. If the thickness of the outer shell is thin, the amount of exposure of the inner core is large, so it tends to be excellent in usability. The thickness of the outer shell with respect to the radial length of the inner core is preferably 10-100%, more preferably 20-50%. The solid writing material according to the present invention can also be used for uses other than pencils, such as mechanical pencil leads and crayons, and the thickness and length can be appropriately adjusted according to the use.

The solid writing material according to the present invention can be written on various writing surfaces. Furthermore, when a reversible thermochromic pigment is used as the coloring material, the handwriting can be discolored by rubbing with a finger or applying a heating tool or a cooling tool.

Examples of the heating device include an electric heating discoloring device equipped with a resistance heating element, a heating discoloring device filled with warm water, and a hair dryer. Used.

The friction member is preferably made of an elastic body such as an elastomer or a plastic foam, which is highly elastic and is capable of generating moderate friction during friction and generating frictional heat. Silicone resin, SEBS resin (styrene-ethylene-butylene-styrene block copolymer), polyester-based resin, or the like can be used as the material of the friction member. As for the friction member, a solid writing body and a separate friction body, which is a member of arbitrary shape, can be combined to obtain a solid writing body set. By providing the friction member on the exterior of the writing instrument, it becomes excellent in portability. Specifically, there is a form in which a friction member is provided in a shape such as a pencil or a crayon whose exterior is made of wood or paper.

Examples of the cooling/heating device include a cold-heat discoloring device using a Peltier element, cold water, a cold-heat discoloring device filled with a refrigerant such as ice chips, a refrigerant, and a refrigerator or a freezer.

Examples are described below, but the present invention is not limited to these examples.
The weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC method), and the melt flow rate (MFR) is a value measured according to ASTM D1238 under the conditions of 230°C and a load of 2.16 kg. is.

(Production of microcapsule pigment A)
5 parts by mass of 2-(2-chloroanilino)-6-di-n-butylaminofluorane as component (a) and 5 parts by mass of 2,2-bis(4'-hydroxyphenyl)hexafluoropropane as component (b) , 4,4′-(2-methylpropylidene)bisphenol 3.0 parts by mass, and (C) 50 parts by mass of 4-benzyloxyphenylethyl laurate as component (C). Then, a solution obtained by mixing 30.0 parts by mass of an aromatic isocyanate prepolymer as a wall film material and 40.0 parts by mass of a co-solvent was emulsified and dispersed in an 8% polyvinyl alcohol aqueous solution, followed by continuing stirring while heating. , and 2.5 parts by mass of a water-soluble aliphatic modified amine were added, and stirring was continued to obtain a reversible thermochromic microcapsule suspension. The suspension was centrifuged to isolate the reversible thermochromic microcapsules. The average particle size of the microcapsules is 2.3 μm, t ₁ : -8°C, t ₂ : -1°C, t ₃ : 52°C, t ₄ : 65°C. The color changed reversibly from black to colorless and from colorless to black.

(Production of microcapsule pigment B)
2.0 parts by mass of 3-(4-diethylamino-2-hexyloxyphenyl)-3-(1)-ethyl-2-methylindol-3-yl)-4-azaphthalide as component (a), component (b) 4.0 parts by mass of 1,1-bis(4′-hydroxyphenyl)hexafluoropropane, 4.0 parts by mass of 1,1-bis(4′-hydroxyphenyl)n-decane, and caprylic acid as component (C) A microcapsule pigment was obtained in the same manner as for microcapsule pigment A, except that a thermochromic color memory composition containing 50.0 parts by mass of 4-benzyloxyphenylethyl (melting point 57° C.) was used. The microcapsule pigment has an average particle diameter of 3.0 μm and exhibits behavior having hysteresis characteristics of t ₁ : −24° C., t ₂ : −10° C., t ₃ : 42° C., and t ₄ : 55° C. , the color changed reversibly from blue to colorless and from colorless to blue.

(Production of microcapsule pigment C)
(A) 5.0 parts by mass of 9-ethyl(3-methylbutyl)amino-spiro[12H-benzo(α)xanthene-12,1′(3′H)-isobenzofuran]-3′-one as a component, ( b) 3.0 parts by mass of 4,4'-(2-ethylhexane-1,1-diyl)diphenol and 5.0 parts of 2,2-bis(4'-hydroxyphenyl)-hexafluoropropane as components; A thermochromic color-memory composition comprising 50.0 parts by mass of 4-benzyloxyphenylethyl caprate as the component (C) was heated and dissolved, and 30.0 parts by mass of an aromatic isocyanate prepolymer as a wall film material, A solution mixed with 40.0 parts by mass of a co-solvent is emulsified and dispersed in an aqueous solution of 8% polyvinyl alcohol, and the mixture is stirred while being heated. Then, 2.5 parts by mass of a water-soluble aliphatic modified amine is added and further stirred. to obtain a thermally discolored microcapsule suspension. The suspension was centrifuged to isolate thermochromic microcapsules.
The average particle size of the microcapsules is 2.3 μm, t ₁ : -20°C, t ₂ : -10°C, t ₃ : 48°C, t ₄ : 58°C, exhibiting behavior having hysteresis characteristics, The color changed reversibly from pink to colorless and from colorless to pink.

The following table shows the compositions of the solid writing materials of Examples and Comparative Examples. In addition, the numerical value of the composition in a table|surface shows a mass part.

The content of raw materials in the table will be explained along with the note numbers.
(1) Sanyo Chemical Industries Co., Ltd., trade name: Sanwax 171-P
(2) Product name: HS Crysta 4100, manufactured by Toyokuni Oil Co., Ltd.
(3) Mitsui Chemicals, Inc., trade name: Hi-Wax 2203A
(4) Daiichi Kogyo Seiyaku Co., Ltd., trade name: Sugar Wax F-10
(5) Fuji Talc Industry Co., Ltd., trade name: FH-105
(6) Clariant, trade name: Licocene PP1502 (weight average molecular weight: 15,500, softening point: 85°C)
(7) Clariant, trade name: Licocene PP1302 (weight average molecular weight: 6,400, softening point: 90°C)
(8) Idemitsu Kosan Co., Ltd., trade name: L-MODU S400 (weight average molecular weight: 45,000, softening point: 93°C, MFR: 2000)
(9) Idemitsu Kosan Co., Ltd., trade name: L-MODU S901 (weight average molecular weight: 130,000, softening point: 120°C, MFR: 50)
(10) Japan Polypropylene Corporation, trade name: Novatec PP MA3 (weight average molecular weight: 397,000, softening point: 165°C, MFR: 11)
(11) BASF, trade name: TINUVIN770DF

(Manufacturing solid cursive)
Each of the above formulations is kneaded with a kneader, and the resulting kneaded product is compression molded with a press set to an outer diameter of φ3 mm and a length of 60 mm, cooled to −20 ° C., and returned to room temperature to solid writing. A body (pencil core) was obtained.

The following tests were performed on each solid writing material obtained in the above examples and comparative examples. In Comparative Example 4, although molding was possible, the strength was not sufficient for writing due to the presence of insoluble components, and the amount of abrasion and concentration could not be measured.
<Bending strength measurement method>
JIS S6006-2007 stipulated strength test (40 mm between fulcrums, 10 mm / min) using Rheotec Co., Ltd. (FUDOH RHEO METER RT-1003A-D PSO) to measure the bending strength of the pencil lead by a three-point bending test. was measured. Each numerical value is an average value of 10 measurements.
<Abrasion amount test method>
The change in weight (mg/m) of the core was measured when writing was performed in the density test specified in JIS S 6006-2007 (writing angle 75°, load 400 gf, writing distance 6 m). Each numerical value is an average value of three measurements.
<Method for measuring concentration>
Visually check the drawing (writing paper) of the pencil core written in the density test specified in JIS S 6006-2007 (writing angle 75 °, load 400 gf, writing distance 6 m). It was measured using a fluorescence spectrodensitometer (FD-7) manufactured by Sanyo Co., Ltd. using a filter matched to the hue of the handwriting. Each numerical value is an average value of 10 measurements.
The results of the tests are shown below.

The evaluation of the symbols in the table is as follows.
Visual observation result of density ◯: Uniform and dark handwriting is obtained.
x: The handwriting is faint, or mottled handwriting is obtained.

Production of Pencils Six pencils were obtained by storing and molding the solid writing bodies obtained in Examples 1 to 6 in a round outer barrel (wooden barrel).
When the pencil was used to write on paper, black, pink, blue, red, and ultramarine traces could be formed.
The handwritings formed by the pencils using the cores of Examples 1 to 4 were decolored (erased) by rubbing with a friction body made of SEBS resin.

Preparation of pencil with friction body A pencil with a friction body was obtained by fixing a cylindrical friction body made of SEBS resin to the rear end of the pencil using the lead of Examples 1 to 4 via a metal connecting member. .
The handwriting formed on the paper surface by using the pencil with the friction body is erased by rubbing with the friction body provided at the rear end, and the pencil with the friction body is excellent in portability and convenient. I was able to

Preparation of Solid Writing Set A solid writing set was obtained by combining the pencils using the cores of Examples 1 to 4 with a rectangular parallelepiped friction body made of SEBS resin.
The handwriting formed on the paper surface with the pencil was erased by rubbing with a friction body, and a more convenient set was obtained that facilitated writing and erasing.

Claims (4)

A reversible thermochromic composition comprising (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) a reaction medium for controlling the color reaction of (a) and (b) above. A microcapsule pigment encapsulated in microcapsules, an excipient, a filler, a binder resin, and a weight average molecular weight of 200,000 or less and ASTM D 1238: Melt flow measured at 230 ° C. and a load of 2.16 kg A solid writing material comprising polypropylene having a rate (MFR) of 50 to 2500 g/10 min, wherein the polypropylene content is 5% by mass or less in the total mass. The solid longhand material according to claim 1, wherein said polypropylene has a softening point in the range of 80 to 125°C. 3. The solid writing object according to claim 1, further comprising a friction member. A solid longhand set comprising the solid longhand according to any one of claims 1 to 3 and a friction body.