JPH11335615A - Production of baked color pencil lead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a baked color pencil lead exhibiting excellent color while keeping high mechanical strengths and smooth writing feeling by impregnating an ink into a porous rod formed from a specific compounded composition. SOLUTION: The objective color pencil lead is produced by impregnating an ink in the pores of a porous rod containing silicon nitride formed as a binder and produced by mixing and extruding a compounded composition containing at least (A) an extender material, (B) an organic excipient (preferably a depolymerizable resin such as polymethyl methacrylate) and (C) a perhydropolysriazane and heat-treating the extruded rod in nitrogen atmosphere. The component C is a ceramic precursor polymer forming silicon nitride by baking preferably at 600 deg.C in nitrogen atmosphere and unstable to water and alcohol and, accordingly, the preparation of the compounded composition is preferably carried out in a dried environment. The compounding amount of the component C is preferably 15-40 wt.% based on the extender material to be compounded.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、十分な発色性、描
線濃度をもちながら、機械的強度、即ち、曲げ強度、引
張強度、衝撃強度等に優れた、焼成芯体にインクを含浸
した焼成色鉛筆芯の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fired core obtained by impregnating a fired core with ink while having sufficient color developing properties and drawing line density and excellent mechanical strength, that is, bending strength, tensile strength and impact strength. The present invention relates to a method for producing a colored pencil lead.

【０００２】[0002]

【従来の技術】従来の焼成色鉛筆芯は、結合材として一
種及び／又は二種以上の粘土等が用いられ、これに窒化
硼素等の体質材、更に必要に応じて耐熱性の顔料、反応
促進材を添加、配合した配合組成物を混練し、この混練
物を押出成形した後、熱処理を経て多孔質焼成芯体と
し、この芯体の気孔中に染料および顔料から成るインク
等を充填させて色鉛筆芯としていた。この時、色鉛筆芯
の重要特性としては、機械的強度が強く、発色性が良
く、筆記描線の濃度が濃いものが要求されている。2. Description of the Related Art A conventional baked color pencil lead uses one or / and two or more kinds of clays as a binder, a body material such as boron nitride, a heat-resistant pigment if necessary, and a reaction accelerator. The kneaded mixture was kneaded with the added composition, and the kneaded product was extruded, and then subjected to a heat treatment to form a porous fired core, and the pores of the core were filled with an ink or the like comprising a dye and a pigment. I had a colored pencil lead. At this time, as the important characteristics of the color pencil lead, those having high mechanical strength, good coloring properties, and high density of writing lines are required.

【０００３】ところが、従来の焼成色鉛筆芯は機械的強
度が充分でなく、濃度および発色性においても充分なも
のが得られていないのが現状である。そこで、上記の要
求を達成するためには、充分な機械的強度を保持しつ
つ、気孔率を増加させることにより芯体に充填されるイ
ンク量を多くする必要がある。また、従来結合材として
用いられている粘土等による焼成芯体は、窒化硼素等の
体質材と粘土等の結合材の焼結力が弱く、粘土等自身の
強度も低いため、得られる焼成色鉛筆芯は実用強度に達
していないのが現状である。更に、粘土は不純物を含ん
でいるため、得られる焼成芯体は一般に有色となり、描
線の発色性に悪影響を与えることとなる。特に、淡色系
の描線のくすんだ色の原因となっている。[0003] However, at present, conventional baked color pencil cores do not have sufficient mechanical strength and do not have sufficient density and coloring properties. Therefore, in order to achieve the above requirements, it is necessary to increase the porosity while maintaining sufficient mechanical strength to increase the amount of ink to be filled in the core. In addition, the fired core made of clay or the like, which has been conventionally used as a binder, has a weak sintering force between the body material such as boron nitride and the binder such as clay, and the strength of the clay or the like itself is low. At present, the core has not reached practical strength. Further, since the clay contains impurities, the fired core obtained is generally colored, which has an adverse effect on the coloring of the drawn lines. In particular, it causes the dull color of the light-colored lines.

【０００４】本発明者らは、上記の課題等を解決する方
法として、少なくとも体質材と有機質の賦形材を含む配
合組成物を混練、押出成形、非酸化性雰囲気で焼成する
ことにより、該有機質の賦形材が炭化された炭化物をバ
インダーとする第１焼成芯体を形成し、該第１焼成芯体
を酸化雰囲気中で加熱して炭化物のバインダーを酸化除
去させた少なくとも体質材からなる第２焼成芯体を形成
し、該第２焼成芯体の気孔内に、ペルヒドロポリシラザ
ン含有液を含浸し、窒素雰囲気等の不活性雰囲気中又は
アンモニアガス雰囲気中での熱処理により窒化珪素を生
成させた第３焼成芯体を形成し、該第３焼成芯体の気孔
内にインクを充填させてなる焼成色鉛筆芯及びその製造
方法を提案している（特開平８−４８９３１号）。この
製造方法等は、十分な発色性、描線濃度をもちながら、
機械的強度等に優れた焼成色鉛筆芯が得られるものであ
る。As a method for solving the above-mentioned problems and the like, the present inventors knead, extrude, and bake in a non-oxidizing atmosphere a compounded composition containing at least a body material and an organic excipient. A first fired core body is formed by using a carbide obtained by carbonizing an organic excipient as a binder, and the first fired core body is heated in an oxidizing atmosphere to oxidize and remove the carbide binder. A second calcined core is formed, and the pores of the second calcined core are impregnated with a perhydropolysilazane-containing liquid, and silicon nitride is generated by heat treatment in an inert atmosphere such as a nitrogen atmosphere or an ammonia gas atmosphere. There has been proposed a fired pencil lead obtained by forming a fired third fired core and filling the pores of the third fired core with ink (JP-A-8-48931). This production method, etc., has sufficient color developability, line density,
A fired colored pencil lead excellent in mechanical strength and the like can be obtained.

【０００５】しかしながら、上記製造方法等には、以下
の(1)〜(3)について若干の課題を有している。 (1) 炭素をバインダーとする黒色の第１焼成芯体を酸化
焼成して得た白色の第２焼成芯体は非常に脆い芯体のた
め、芯の形状を崩しやすい。 (2) 焼成処理を数回繰り返さなければならない等工程が
煩雑になる。 (3) ペルヒドロポリシラザン含有液の含浸状態により最
終製品の品質のバラツキ等の影響が若干ある。However, the above-mentioned manufacturing method and the like have some problems in the following (1) to (3). (1) Since the black second fired core obtained by oxidizing and firing the black first fired core using carbon as a binder is a very brittle core, the shape of the core is easily broken. (2) The process becomes complicated, for example, the firing process must be repeated several times. (3) The quality of the final product is slightly affected by the impregnation state of the liquid containing perhydropolysilazane.

【０００６】[0006]

【発明が解決しようとする課題】本発明の目的は、上記
従来技術の課題を解決すると共に、上記発明者らの先行
技術を更に改良することであり、機械的強度と滑らかな
書き味を保持しつつ、更に優れた発色性を有する焼成色
鉛筆芯の製造方法を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to further improve the prior art of the present inventors, and to maintain mechanical strength and smooth writing taste. Another object of the present invention is to provide a method for producing a fired colored pencil lead having more excellent coloring properties.

【０００７】[0007]

【課題を解決するための手段】本発明者らは、前記課題
を解決するために鋭意研究を行った結果、多孔質芯体の
気孔中にインクを存在させてなる焼成色鉛筆芯におい
て、該多孔質焼結体を得る際に、少なくとも体質材と有
機質の賦形材を含む配合組成物と共に、ペルヒドロポリ
シラザンを配合し、これらの配合組成物を、混合、押出
成形、窒素雰囲気中等の不活性雰囲気中で加熱処理によ
り、結合材としての窒化珪素を生成させることによっ
て、上記目的の焼成色鉛筆芯の製造方法が得られること
を見い出し、本発明を完成するに至ったのである。すな
わち、本発明の焼成色鉛筆芯の製造方法は、少なくとも
体質材と有機質の賦形材とペルヒドロポリシラザンとを
含む配合組成物を、混合、押出成形、窒素雰囲気中で加
熱処理をすることにより、結合材としての窒化珪素を生
成させた多孔質芯体を形成し、該多孔質芯体の気孔内に
インクを充填させてなることを特徴とする。Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have found that a fired colored pencil lead obtained by allowing ink to exist in the pores of a porous core has a porous core. When obtaining a porous sintered body, a perhydropolysilazane is blended together with a blended composition containing at least a body material and an organic excipient, and these blended compositions are mixed, extruded, inert in a nitrogen atmosphere, or the like. The inventors have found that a method for producing a fired pencil lead having the above object can be obtained by generating silicon nitride as a binder by heat treatment in an atmosphere, thereby completing the present invention. That is, the method for producing a fired colored pencil lead of the present invention comprises mixing a composition containing at least a body material, an organic excipient and perhydropolysilazane, mixing, extrusion, and heat treatment in a nitrogen atmosphere. It is characterized in that a porous core body in which silicon nitride as a binder is generated is formed, and ink is filled in pores of the porous core body.

【０００８】[0008]

【発明の実施の形態】以下に、本発明の実施形態を詳し
く説明する。本発明の焼成色鉛筆芯の製造方法は、少な
くとも体質材と有機質の賦形材とペルヒドロポリシラザ
ンとを含む配合組成物を、混合、押出成形、窒素雰囲気
中で加熱処理をすることにより、結合材としての窒化珪
素を生成させた多孔質芯体を形成し、該多孔質芯体の気
孔内にインクを充填させてなることを特徴とするもので
ある。Embodiments of the present invention will be described below in detail. The method for producing a fired colored pencil lead of the present invention comprises the steps of: mixing, extruding, and heat-treating a blended composition containing at least a body material, an organic excipient and perhydropolysilazane in a nitrogen atmosphere; And forming a porous core body having silicon nitride formed therein, and filling ink into pores of the porous core body.

【０００９】本発明で用いる体質材としては、従来の焼
成型の色鉛筆芯に使用されているものであれば、いずれ
も使用可能である。例えば、酸化チタン、雲母、タル
ク、窒化硼素、シリカ、アルミナ、炭酸カルシウム等白
色系のものや、充填するインクの色相によっては二硫化
モリブデン、二硫化タングステン等有色系のものも使用
することができ、当然これら数種類の混合物も使用でき
る。また、必要に応じて耐熱性顔料を配合してもよい。
また、有機質の賦形材としては、充填するインクの色相
によっては、多孔質芯体中への樹脂などの有機物による
炭素等の残存により、鮮明な色相を得にくくなるため、
ポリメタクリル酸メチル、ポリスチロール、ポリエチレ
ンなどといった解重合型の樹脂が好ましい。もちろん、
ポリ塩化ビニル樹脂、塩素化ポリ塩化ビニル樹脂、ポリ
ビニルアルコールなどの熱可塑性樹脂、フラン樹脂、フ
ェノール樹脂、エポキシ樹脂などの熱硬化性樹脂、石油
アスファルト、コールタールピッチ、ナフサ分解ピッ
チ、合成樹脂の乾留ピッチなどのピッチ類等もペルヒド
ロポリシラザンを窒化珪素化させる熱処理の後に、酸化
雰囲気中の熱処理によって、残存する炭素成分を除去す
る前提であれば使用可能である。As the extender used in the present invention, any material can be used as long as it is used for a conventional firing type color pencil lead. For example, titanium oxide, mica, talc, boron nitride, silica, alumina, calcium carbonate and other white materials, and depending on the hue of the ink to be filled, molybdenum disulfide and tungsten disulfide can also be used. Of course, mixtures of these several types can also be used. Moreover, you may mix | blend a heat resistant pigment as needed.
Further, as an organic excipient, depending on the hue of the ink to be filled, it is difficult to obtain a clear hue due to the remaining carbon or the like by an organic substance such as a resin in the porous core.
Depolymerization type resins such as polymethyl methacrylate, polystyrene, and polyethylene are preferred. of course,
Thermoplastic resins such as polyvinyl chloride resin, chlorinated polyvinyl chloride resin, and polyvinyl alcohol; thermosetting resins such as furan resin, phenolic resin and epoxy resin; petroleum asphalt, coal tar pitch, naphtha cracked pitch, and dry distillation of synthetic resin Pitches such as pitch can be used as long as the remaining carbon component is removed by heat treatment in an oxidizing atmosphere after heat treatment for siliconizing perhydropolysilazane.

【００１０】本発明で用いるペルヒドロポリシラザン
は、主鎖に（−Ｓｉ−Ｎ−）構造を有し、側鎖には水素
のみが結合した熱硬化型無機高分子ポリマーで、窒素雰
囲気中で４００℃以上、好ましくは、６００℃以上の焼
成で窒化珪素を生成するセラミックス前駆体ポリマーで
ある。また、上記ペルヒドロポリシラザンは、有機溶剤
に可溶であるため、上記体質材や有機質の賦形材等の他
の配合組成物と均一混合させるために、有機溶剤で希釈
して使用することも可能である。使用する有機溶剤とし
ては、例えば、ベンゼン、トルエン、キシレン、エーテ
ル、ＴＨＦ、塩化メチレン、四塩化炭素等、芳香族炭化
水素系等の有機溶剤が挙げられる。The perhydropolysilazane used in the present invention is a thermosetting inorganic high molecular polymer having a (—Si—N—) structure in a main chain and only hydrogen bonded to a side chain. A ceramic precursor polymer that forms silicon nitride when fired at a temperature of at least 600C, preferably at least 600C. Further, since the perhydropolysilazane is soluble in an organic solvent, it may be used after being diluted with an organic solvent so as to be uniformly mixed with another compounding composition such as the above-mentioned constitutional material or organic excipient. It is possible. Examples of the organic solvent to be used include organic solvents such as benzene, toluene, xylene, ether, THF, methylene chloride, carbon tetrachloride, and aromatic hydrocarbons.

【００１１】更に、本発明おいて使用するセラミックス
前駆体ポリマーであるペルヒドロポリシラザンは、水や
アルコール等に対して、安定性が低いために、原材料と
なる体質材と有機質の賦形材等は十分に乾燥されたもの
を使用し、また、相対湿度を２０％以下に制御された低
湿度の雰囲気で上記配合組成物を調整する必要がある。
相対湿度が２０パーセントを越える雰囲気で上記配合組
成物を調整すると、得られる焼成鉛筆芯は品質のバラツ
キ等の影響が大きくなる。また、ペルヒドロポリシラザ
ンの配合量は、目的の焼成色鉛筆芯の用途などに応じて
適宜調整でき、配合する体質材に対して、１５〜４０重
量％、好ましくは、２０〜３５重量％である。Further, perhydropolysilazane, which is a ceramic precursor polymer used in the present invention, has low stability to water, alcohol, and the like. It is necessary to use a sufficiently dried one and to adjust the above-mentioned composition in a low humidity atmosphere in which the relative humidity is controlled to 20% or less.
When the above composition is adjusted in an atmosphere having a relative humidity of more than 20%, the obtained baked pencil lead is greatly affected by quality variations and the like. The amount of perhydropolysilazane can be appropriately adjusted according to the intended use of the fired colored pencil lead, and is 15 to 40% by weight, preferably 20 to 35% by weight, based on the body material to be mixed.

【００１２】これらの原材料である体質材、有機質の賦
形材、ペルヒドロポリシラザン等を十分に乾燥し、更に
は、相対湿度を２０％以下に制御された低湿度の雰囲気
中で、混合された配合組成物をヘンシェルミキサー、加
圧ニーダー、二本ロール等で十分混練した後、押出成形
機により細線状等に押出成形し、次いで、窒素雰囲気中
で４００℃、好ましくは６００℃以上で、かつ、体質材
の熱分解又は脱水等を起こす温度より低い温度で熱処理
することにより、セラミックス前駆体ポリマーであるペ
ルヒドロポリシラザンより生成した窒化珪素をバインダ
ーとする多孔質芯体が得られる。得られた多孔質芯体
は、結合材としての窒化珪素が芯体中に微細で均一に分
散して生成するものとなり、更に、体質材が高配向して
いるため少量の窒化珪素の生成で芯体の強度を発現しや
すく、筆記時の芯体の崩れも均一となる。The raw materials such as the body material, the organic excipient, perhydropolysilazane and the like are sufficiently dried and further mixed in a low humidity atmosphere in which the relative humidity is controlled to 20% or less. After sufficiently kneading the compounded composition with a Henschel mixer, a pressure kneader, a two-roll mill, and the like, extruding into a fine wire or the like with an extruder, and then at 400 ° C., preferably 600 ° C. or higher in a nitrogen atmosphere, and By performing a heat treatment at a temperature lower than the temperature at which the thermal decomposition or dehydration of the body material occurs, a porous core using silicon nitride generated from perhydropolysilazane as a ceramic precursor polymer as a binder is obtained. In the obtained porous core, silicon nitride as a binder is formed by being finely and uniformly dispersed in the core, and furthermore, since the base material is highly oriented, a small amount of silicon nitride is generated. The strength of the core body is easily developed, and the collapse of the core body during writing becomes uniform.

【００１３】本発明において、焼成色鉛筆芯は、上記で
得られた多孔質芯体の気孔内に、インクを充填させるこ
とにより得られる。多孔質芯体に含浸するインクとして
は、従来公知の色鉛筆用のものであればいずれも使用す
ることができる。例えば、染顔、顔料等の着色剤を動植
物油、合成油、アルコール類、炭化水素油、水等に溶
解、分散させ、あるいは必要に応じて樹脂、界面活性剤
等をさらに添加し製造された一般的に用いられている印
刷用インク、スタンプインク、ボールペンインク、水性
筆記用インク等が用いられる。また、多孔質芯体にイン
クを含浸する方法としては、例えば、多孔質芯体をイン
ク中に浸漬し、加熱、減圧、加圧等の条件下で気孔内に
充填させる。さらに、繰り返し含浸を行ってもよい。In the present invention, the fired pencil lead is obtained by filling the pores of the porous core obtained above with ink. As the ink for impregnating the porous core, any conventionally known ink for color pencils can be used. For example, dyeing, coloring agents such as pigments, animal and vegetable oils, synthetic oils, alcohols, hydrocarbon oils, dissolved in water or the like, dispersed or, if necessary, resins, surfactants and the like are further added and manufactured. Commonly used printing inks, stamp inks, ballpoint pen inks, aqueous writing inks and the like are used. As a method of impregnating the porous core with the ink, for example, the porous core is immersed in the ink and filled in the pores under conditions such as heating, decompression, and pressurization. Further, repeated impregnation may be performed.

【００１４】このように構成される本発明の焼成色鉛筆
芯では、ペルヒドロポリシラザンを少なくとも体質材と
有機質の賦形材と共に直接配合した配合組成物を用いる
ために、芯体を脆くするという工程を経ることなく、単
純な焼成工程で多孔質芯体が得られ、更に、単純な焼成
工程のために、品質のバラツキの少ない、高強度の多孔
質芯体が得られるものとなる。In the fired colored pencil lead of the present invention thus constituted, a step of weakening the lead is used because a blended composition in which perhydropolysilazane is directly blended with at least a body material and an organic excipient is used. Without passing through, a porous core can be obtained by a simple firing step, and a high-strength porous core with less variation in quality can be obtained by the simple firing step.

【００１５】[0015]

【実施例】次に、本発明を実施例により、更に具体的に
説明するが、本発明はこの実施例によって何等限定され
るものではない。Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

【００１６】 （実施例１） ペルヒドロポリシラザン １２重量部 キシレン ２４重量部 窒化硼素 ６０重量部 ポリエチレン ２８重量部 パラフィン ３０重量部 相対湿度を２０％以下に制御された低湿度の雰囲気中に
おいて、上記ペルヒドロポリシラザンをキシレンに溶解
させてから、他の配合物組成物をヘンシェルミキサーで
混合分散し、加圧ニーダー、二本ロールで混練した後、
細線状に押出成形し、窒素雰囲気中で６００℃にて焼成
して、直径０．５７ｍｍの白色の多孔質芯体を得た。次
に、赤色インクに上記多孔質芯体を浸し、７０℃で２４
時間放置した。この赤色インクが充填された多孔質芯体
表面をアルコールで洗浄し、直径０．５７ｍｍの赤色の
焼成色鉛筆芯を得た。Example 1 Perhydropolysilazane 12 parts by weight Xylene 24 parts by weight Boron nitride 60 parts by weight Polyethylene 28 parts by weight Paraffin 30 parts by weight In a low humidity atmosphere in which the relative humidity is controlled to 20% or less, After dissolving the hydropolysilazane in xylene, the other compound composition was mixed and dispersed with a Henschel mixer, kneaded with a pressure kneader, and two rolls.
It was extruded into a thin wire and fired at 600 ° C. in a nitrogen atmosphere to obtain a white porous core having a diameter of 0.57 mm. Next, the porous core is immersed in red ink,
Left for hours. The surface of the porous core filled with the red ink was washed with alcohol to obtain a red fired pencil lead having a diameter of 0.57 mm.

【００１７】 （比較例１） 窒化硼素 ５０重量部 塩化ビニル樹脂 ５０重量部 ジオクチルフタレート（ＤＯＰ） ２０重量部 ステアリン酸亜鉛 １重量部 上記配合組成物をヘンシェルミキサーで混合分散し、加
圧ニーダー、二本ロールで混練した後、細線状に押出成
形し、これから残留する可塑剤を除去すべく空気中で１
８０℃にて熱処理し、窒素雰囲気中にて１０００℃で焼
成し、第１焼成芯体を得た。この第１焼成芯体を酸化雰
囲気で約７００℃で加熱焼成して残留している炭素化し
た樹脂分を除去して白色の第２焼成芯体を得た。この第
２焼成芯体にペルヒドロポリシラザン含有液（２０％キ
シレン溶液）を室温で１日含浸後、窒素雰囲気中で６０
０℃で焼成して焼成芯体を得た。更にこの焼成芯体にペ
ルヒドロポリシラザン溶液を含浸せしめ、焼成工程をさ
らに１回繰り返し、直径０．５７ｍｍの白色の第３焼成
芯体を得た。次いで、赤色インクに上記多孔質芯体の第
３焼成芯体を浸し、７０℃で２４時間放置した。この赤
色インクが充填された多孔質芯体表面をアルコールで洗
浄し、直径０．５７ｍｍの赤色の焼成色鉛筆芯とした。(Comparative Example 1) Boron nitride 50 parts by weight Vinyl chloride resin 50 parts by weight Dioctyl phthalate (DOP) 20 parts by weight Zinc stearate 1 part by weight The above composition was mixed and dispersed by a Henschel mixer. After kneading with this roll, it is extruded into a fine wire and then removed in air to remove the residual plasticizer.
Heat treatment was performed at 80 ° C., and firing was performed at 1000 ° C. in a nitrogen atmosphere to obtain a first fired core. The first fired core was heated and baked at about 700 ° C. in an oxidizing atmosphere to remove the remaining carbonized resin, thereby obtaining a white second fired core. The second calcined core body was impregnated with a perhydropolysilazane-containing liquid (20% xylene solution) at room temperature for one day, and then impregnated in a nitrogen atmosphere for 60 days.
It was fired at 0 ° C. to obtain a fired core. The fired core was further impregnated with a perhydropolysilazane solution, and the firing step was repeated once more to obtain a white third fired core having a diameter of 0.57 mm. Next, the third fired core of the porous core was immersed in red ink and left at 70 ° C. for 24 hours. The surface of the porous core filled with the red ink was washed with alcohol to obtain a red fired colored pencil lead having a diameter of 0.57 mm.

【００１８】上記で得られた実施例１及び比較例１の焼
成色鉛筆芯について、ＪＩＳ−Ｓ−６００５−１９８９
に準拠して三点曲げ強度試験（ＭＰａ）、官能評価によ
る書き味、描線の発色について評価した。これらの結果
を下記表１に示す。The baked colored pencil cores of Example 1 and Comparative Example 1 obtained above were subjected to JIS-S-6005-1989.
The three-point bending strength test (MPa), the writing quality by sensory evaluation, and the coloring of the drawing line were evaluated in accordance with the above. The results are shown in Table 1 below.

【００１９】[0019]

【表１】 [Table 1]

【００２０】上記表１の結果から明らかなように、本発
明範囲の実施例１の焼成色鉛筆芯は、従来例となる比較
例１の焼成色鉛筆芯に較べて、脆い芯体にペルヒドロポ
リシラザンを含浸したり、焼成工程を繰り返す等の煩雑
な工程を経ずとも、曲げ強度が同等の焼成色鉛筆芯が得
られることが判明した。更に、比較例１は、芯の固体間
に若干の書き味のムラ、あるいは硬さのムラが感じられ
るのに対して、実施例１では、バラツキもなく極めて良
好な書き味の焼成色鉛筆芯が得られた。As is clear from the results shown in Table 1, the fired pencil lead of Example 1 in the scope of the present invention has a brittle core made of perhydropolysilazane as compared with the fired pencil lead of Comparative Example 1 which is a conventional example. It has been found that a baked colored pencil lead having the same bending strength can be obtained without performing complicated steps such as impregnation and repeating the baking step. Furthermore, in Comparative Example 1, slight unevenness of writing taste or unevenness of hardness was felt between the solids of the core, whereas in Example 1, a fired color pencil core having extremely good writing taste without variation was obtained. Obtained.

【００２１】[0021]

【発明の効果】本発明によれば、ペルヒドロポリシラザ
ンを少なくとも体質材と有機質の賦形材と共に配合し
て、窒化珪素をバインダーとした多孔質芯体を得ること
により、気孔率が大きくても機械的強度に優れ、実用上
折れ難く、更にインク充填量が多くなることにより、き
わめて優れた発色が得られ、それと同時に、良好な書き
味を有する焼成色鉛筆芯の製造方法が提供される。According to the present invention, perhydropolysilazane is blended together with at least a filler and an organic excipient to obtain a porous core using silicon nitride as a binder, so that even if the porosity is large, By providing excellent mechanical strength, practically not easily broken, and further increasing the ink filling amount, extremely excellent coloring can be obtained, and at the same time, a method for producing a fired pencil lead having good writing quality is provided.

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 少なくとも体質材と有機質の賦形材とペ
ルヒドロポリシラザンとを含む配合組成物を、混合、押
出成形、窒素雰囲気中で加熱処理をすることにより、結
合材としての窒化珪素を生成させた多孔質芯体を形成
し、該多孔質芯体の気孔内にインクを充填させてなるこ
とを特徴とする焼成色鉛筆芯の製造方法。1. A compound composition containing at least a body material, an organic excipient and perhydropolysilazane is mixed, extruded, and heat-treated in a nitrogen atmosphere to produce silicon nitride as a binder. A method for producing a fired colored pencil lead, comprising: forming a porous core body, and filling ink into pores of the porous core body.