JPH0543760B2 - - Google Patents
Info
- Publication number
- JPH0543760B2 JPH0543760B2 JP59215926A JP21592684A JPH0543760B2 JP H0543760 B2 JPH0543760 B2 JP H0543760B2 JP 59215926 A JP59215926 A JP 59215926A JP 21592684 A JP21592684 A JP 21592684A JP H0543760 B2 JPH0543760 B2 JP H0543760B2
- Authority
- JP
- Japan
- Prior art keywords
- graphite
- pencil lead
- lead
- polymerized
- strength
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 21
- 239000010439 graphite Substances 0.000 claims description 16
- 229910002804 graphite Inorganic materials 0.000 claims description 16
- 239000011230 binding agent Substances 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 6
- 238000004898 kneading Methods 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 239000003086 colorant Substances 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 125000005397 methacrylic acid ester group Chemical group 0.000 claims description 5
- 238000004040 coloring Methods 0.000 claims description 4
- 238000010304 firing Methods 0.000 claims description 4
- 239000011148 porous material Substances 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 description 4
- 239000011162 core material Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- JHPBZFOKBAGZBL-UHFFFAOYSA-N (3-hydroxy-2,2,4-trimethylpentyl) 2-methylprop-2-enoate Chemical compound CC(C)C(O)C(C)(C)COC(=O)C(C)=C JHPBZFOKBAGZBL-UHFFFAOYSA-N 0.000 description 3
- 229920005992 thermoplastic resin Polymers 0.000 description 3
- 235000021355 Stearic acid Nutrition 0.000 description 2
- 239000012752 auxiliary agent Substances 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 2
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 230000000379 polymerizing effect Effects 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 239000008117 stearic acid Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229920006243 acrylic copolymer Polymers 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000011294 coal tar pitch Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000025 natural resin Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920000193 polymethacrylate Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000010187 selection method Methods 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 239000001993 wax Substances 0.000 description 1
Landscapes
- Inks, Pencil-Leads, Or Crayons (AREA)
Description
（産業上の利用分野）
本発明は濃度、書味を損なわずに強度を向上せ
しめる鉛筆芯の製造方法に関する。
（従来の技術）
従来の鉛筆芯の一般的な製造方法は、天然樹
脂、合成樹脂、コールタールピツチ、アスフアル
ト、熱硬化性初期縮合物等の高温で焼成すると炭
素化する有機物質の単体又は混合体を黒鉛、カー
ボンブラツク等の着色材と共に混練して所望形状
に押出成形したのち高温で焼成して炭化させるも
のである。
そしてこの鉛筆芯の強度を向上させるためにこ
れまでに提示された発明の殆どは、結合材や助剤
の選択及び処理方法に関するものであり、焼成後
の炭素の残塊の多い結合材を使用するものとか、
助剤や熱処理条件により焼成後の炭素の残塊を増
加させるものとかで、炭素の残塊の増加により強
度の向上を図るものである。しかし斯る方法では
強度の向上は得られるが、反面濃度は薄くなり、
又黒鉛特有の潤滑性がこの炭素の残塊によつて包
み込まれ書味が硬く重いものになつていまう欠点
があり、極端な場合は例えば紙面を引つかいてし
まうという現象が生じた。
次に濃度や書味を向上させるものには、結合材
又は着色材と共に解重合型高分子物質を加えて熱
処理時に解重合させる方法とか、昇華性有機化合
物を加えて熱処理時に昇華させる方法とかがあ
り、これらの方法によると芯の中に微細な気孔が
形成されて濃度及び書味の向上がもたらされる
が、反面結合材と着色材の結合力は向上せず強度
の向上は望めないという欠点が存在する。
（発明が解決しようとする問題点）
本発明は上記の欠点を解消し、濃度や書味を損
なうことなく強度を向上させることができる鉛筆
芯の製造方法の提供を目的とするものである。
（問題点を解決するための手段）
本発明は、結合材と混練助剤及び結合材として
用いる熱可塑性樹脂と相溶性があり且つ熱処理時
に於て解重合するメタクリル酸エステルを表面に
重合して表面改質を行なつた着色材としての黒鉛
とを、ヘンシエルキミサー等で混合したのち加圧
ニーダー、二本ロール等で混練し、次いで芯材に
押出成形したのち、100〜200℃で熱処理して残留
する可塑剤分や熱分解物等を除去したのち窒素雰
囲気中で900〜1200℃の温度で焼成してポリメタ
クリル酸エステルを解重合させ芯の中に均一に細
孔を形成させ、次にスピンドル油中に浸漬して油
含浸させ鉛筆芯を製造するものである。
本発明に於て着色材としての黒鉛表面に重合さ
せるメタクリル酸エステルの割合は黒鉛重量の１
〜15％の範囲で望ましは５〜10％の範囲である。
又、本発明に於て使用する結合材には酢酸ビニ
ル樹脂、塩化ビニル樹脂、アクリル樹脂等の熱可
塑性樹脂及びこれらの共重合体が有効であり、又
本発明に於て使用する混練助剤にはパラフインワ
ツクス、カルナパワツクス、ステアリン酸等の滑
剤やDOP、DBP、DBS等の可塑剤を掲げること
ができる。
（作用）
本発明に於ては着色材としての黒鉛表面にメタ
クリル酸エステルを重合させることにより結合
材、混練助剤との混練時に結合材である熱可塑性
樹脂とメタクリル酸エステルが相溶して黒鉛と結
合材との密着性を向上させることになり、又焼成
時にはメタクリル酸エステルが解重合をおこして
炭素の残塊を残さないで内部に均一なミクロボア
ーを形成して吸油量を増大させることになり、よ
つて濃度、書味を損なわずに強度の向上をもたら
すものである。
（実施例）
以下に本発明の実施例とその試験結果を記す。
(1) 第１実施例
黒鉛表面に黒鉛重量の９％のメタクリル酸エス
テル（以下MMAと称す）を重合させた黒鉛55部
に対し、ポリ塩化ビニル45部、ステアリン酸0.5
部、及びDBP23部を加えてヘンシエルキミサー
で混合し加圧ニーダー、二本ロールで混練したの
ち、押出成形により芯状に成形しこれから残留す
る可塑剤分を除去すべく180℃にて10時間熱処理
して固化させ、しかるのち窒素雰囲気中にて常温
から300℃迄は10℃／hr、300℃から1000℃迄は30
℃／hrで昇華さて1000℃にて１時間焼成し、最後
にスピンドル油中に浸漬して油浸させて鉛筆芯を
得る。
(2) 第２実施例
上記の第１実施例で用いたMMAを９％重合し
た黒鉛の代りにMMAを５％重合した黒鉛を用い
又他の組成は同一にして同様の工程を経て鉛筆芯
を得る。
(3) 試験結果
上記の第１実施例及び第２実施例によつて得ら
れた鉛筆芯についてJIS−S6019に基づいて行な
つた濃度、摩擦係数及び曲げ強度についての試験
結果は次の通りである。
尚、比較の為に第１実施例に於てMMAを重合
した黒鉛の代りにMMAを重合させない黒鉛を使
用して製造した鉛筆芯についての試験結果も併記
する。
(Industrial Application Field) The present invention relates to a method for producing a pencil lead that improves strength without impairing density or writing feel. (Prior Art) The general method for manufacturing conventional pencil leads is to use organic substances that are carbonized when fired at high temperatures, such as natural resins, synthetic resins, coal tar pitch, asphalt, and thermosetting initial condensates, either singly or in combination. The body is kneaded with a colorant such as graphite or carbon black, extruded into a desired shape, and then fired at a high temperature to carbonize it. Most of the inventions proposed so far to improve the strength of pencil lead relate to the selection and processing methods of binders and auxiliary agents, and include the use of binders with a large amount of carbon residue after firing. things to do,
This method involves increasing the amount of carbon remaining after firing by using auxiliary agents and heat treatment conditions, and aims to improve the strength by increasing the amount of carbon remaining. However, although this method improves the strength, it also reduces the concentration.
In addition, the lubricity characteristic of graphite is enveloped by the residual carbon mass, resulting in a hard and heavy writing experience, and in extreme cases, for example, a phenomenon occurs in which the writing sticks to the paper surface. Next, methods to improve density and writing feel include adding a depolymerizable polymer substance together with a binder or colorant and depolymerizing it during heat treatment, or adding a sublimable organic compound and sublimating it during heat treatment. These methods form fine pores in the core, improving the density and writing quality, but on the other hand, the disadvantage is that the bonding force between the binding material and the coloring material does not improve, and no improvement in strength can be expected. exists. (Problems to be Solved by the Invention) An object of the present invention is to provide a method for producing a pencil lead that can eliminate the above-mentioned drawbacks and improve the strength without impairing the density or writing feel. (Means for Solving the Problems) The present invention is characterized by polymerizing methacrylic acid ester on the surface which is compatible with the binder, the kneading aid, and the thermoplastic resin used as the binder and which depolymerizes during heat treatment. The surface-modified coloring material, graphite, is mixed with a Henschel chimiser, etc., then kneaded with a pressure kneader, two rolls, etc., then extruded into a core material, and then heated at 100 to 200℃. After heat treatment to remove residual plasticizer and thermal decomposition products, it is fired in a nitrogen atmosphere at a temperature of 900 to 1200℃ to depolymerize the polymethacrylate ester and form pores uniformly in the core. Then, the lead is immersed in spindle oil to be impregnated with oil to produce a pencil lead. In the present invention, the proportion of methacrylic acid ester polymerized on the graphite surface as a colorant is 1% by weight of graphite.
-15%, preferably 5-10%. In addition, thermoplastic resins such as vinyl acetate resin, vinyl chloride resin, acrylic resin, and copolymers thereof are effective as the binder used in the present invention, and the kneading aid used in the present invention Examples include lubricants such as paraffin wax, carnapa wax, and stearic acid, and plasticizers such as DOP, DBP, and DBS. (Function) In the present invention, by polymerizing methacrylic ester on the surface of graphite as a coloring agent, the thermoplastic resin as a binding material and methacrylic ester are compatible with each other during kneading with a binding material and a kneading aid. This improves the adhesion between graphite and the binder, and during firing, the methacrylic acid ester depolymerizes and forms uniform microbore inside without leaving any carbon residue, increasing oil absorption. This results in improved strength without sacrificing density or writing feel. (Example) Examples of the present invention and test results thereof are described below. (1) First Example 55 parts of graphite polymerized with 9% of the weight of graphite methacrylic ester (hereinafter referred to as MMA) on the surface of graphite, 45 parts of polyvinyl chloride, and 0.5 parts of stearic acid.
and 23 parts of DBP were mixed in a Henschel chimiser, kneaded in a pressure kneader and two rolls, and then formed into a core by extrusion molding. Heat-treated for an hour to solidify, then in a nitrogen atmosphere at 10°C/hr from room temperature to 300°C, and at 30°C from 300°C to 1000°C.
It is sublimated at ℃/hr, then fired at 1000℃ for 1 hour, and finally immersed in spindle oil to obtain a pencil lead. (2) Second Example Instead of the graphite polymerized with 9% MMA used in the first example above, graphite polymerized with 5% MMA was used, other compositions were kept the same, and a pencil lead was produced through the same process. get. (3) Test results The test results for density, coefficient of friction, and bending strength of the pencil leads obtained in the first and second examples above were conducted in accordance with JIS-S6019 as follows. be. For comparison, the test results for a pencil lead produced using graphite without MMA polymerization in place of the graphite polymerized with MMA in the first example are also listed.
【表】
（発明の効果）
本発明は上記した如く着色材として表面にメタ
クリル酸エステルを重合した黒鉛を使用すること
を特徴として構成されることにより、実施例の試
験結果により明らかな通り濃度や書味（摩擦係数
が一つの書味の判定基準となる）が損なわれるこ
とがなく、然も強度を大幅に増大する鉛筆芯が得
られるものである。[Table] (Effects of the Invention) As described above, the present invention is characterized by using graphite on the surface of which methacrylic acid ester has been polymerized as a coloring material. It is possible to obtain a pencil lead that does not impair the writing feel (friction coefficient is one criterion for writing taste) and has significantly increased strength.
Claims (1)
成形したのち高温で焼成する鉛筆芯の製造方法に
於て、結合材と相容性があり且つ熱処理時に於て
一部が解重合することにより芯内部に均一な細孔
を形成せしめるメタクリル酸エステルを表面に重
合した黒鉛を着色材として使用することを特徴と
する鉛筆芯の製造方法。1. In the method for manufacturing pencil lead, which involves kneading and extruding coloring materials, binders, and kneading aids and then firing them at high temperatures, the pencil lead is compatible with the binder and partially depolymerized during heat treatment. A method for producing a pencil lead, characterized in that graphite polymerized with methacrylic acid ester on the surface, which forms uniform pores inside the lead, is used as a coloring agent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21592684A JPS6195084A (en) | 1984-10-15 | 1984-10-15 | Manufacture of pencil core |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21592684A JPS6195084A (en) | 1984-10-15 | 1984-10-15 | Manufacture of pencil core |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6195084A JPS6195084A (en) | 1986-05-13 |
| JPH0543760B2 true JPH0543760B2 (en) | 1993-07-02 |
Family
ID=16680547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21592684A Granted JPS6195084A (en) | 1984-10-15 | 1984-10-15 | Manufacture of pencil core |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6195084A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3200292B2 (en) * | 1994-08-05 | 2001-08-20 | 三菱鉛筆株式会社 | Fired colored pencil lead and method for producing the same |
| JP5162827B2 (en) * | 2005-12-27 | 2013-03-13 | ぺんてる株式会社 | Pencil lead manufacturing method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5443013A (en) * | 1977-09-12 | 1979-04-05 | Sony Corp | Sound source device of electronic musical instruments |
| JPS5840595A (en) * | 1981-04-29 | 1983-03-09 | ヘミ−ゲゼルシヤフト・グンデルンハウゼン・ミツト・ベシユレンクテル・ハフツング | Molding for absorbing and shielding sound |
-
1984
- 1984-10-15 JP JP21592684A patent/JPS6195084A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5443013A (en) * | 1977-09-12 | 1979-04-05 | Sony Corp | Sound source device of electronic musical instruments |
| JPS5840595A (en) * | 1981-04-29 | 1983-03-09 | ヘミ−ゲゼルシヤフト・グンデルンハウゼン・ミツト・ベシユレンクテル・ハフツング | Molding for absorbing and shielding sound |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6195084A (en) | 1986-05-13 |
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