JP4390340B2 - Ink composition for writing instruments - Google Patents

Description

（式中、Ｘはフェニレン基、あるいは、炭素数１〜３の範囲のアルキル基置換の、炭素数１〜３の範囲のアルコキシ基置換の、ハロゲン置換の、または、ニトロ基置換のフェニレン基であり、Ｙはフェニル基、あるいは、炭素数１〜３の範囲のアルキル基置換の、炭素数１〜３の範囲のアルコキシ基置換の、ハロゲン置換の、ニトロ基置換のフェニル基であり、Ｚは−ＳＯ₃Ｈ或いは−ＣＯＯＨである。）
【０００７】
（２）上記本発明において有機顔料が赤色顔料であることを特徴とする。
（３）有機顔料に対して（１）の構造を有する化合物の配合比率が１００：１〜４：１であることを特徴とする。
（４）有機溶媒の溶解性パラメーターであるｓｐ値が７〜１３であることを特徴とするインク組成物を提供するものである。
【０００８】
本発明で用いられる一般式（１）で示される構造の化合物は本発明のインク組成物に必須の成分であり、着色剤としての顔料の分散安定性に大きな役割を果たす。その作用メカニズムは定かではないが、以下のように考えられる。
一般式（１）で示される構造の化合物は、有機顔料の表面に疎水性相互作用等の働きにより吸着し、更に有機顔料表面に吸着した一般式（１）の化合物の分子内にある活性な官能基がカチオン性分散剤と親和力を持つことで、有機顔料は有機溶媒中に良好に分散されると考えられる。
【０００９】
【発明の実施の形態】
以下、本発明の実施の形態について詳細に説明する。
本発明で用いられる有機溶媒は請求項の範囲内にある通常筆記具に用いられる有機溶媒であれば特に限定されるものではないが、好ましくは溶解性パラメーターであるｓｐ値が７〜１３の範囲の値を示す有機溶媒が用いられる。
具体的には、アルコール類、グリコール類、グリコールエーテル類、脂肪酸エステル類、ケトン類、エーテル類、脂肪族炭化水素類、芳香族炭化水素類及びこれらの誘導体が挙げられるが、好ましくはアルコール類、グリコールエーテル類及びこれらの誘導体を挙げことが出来る。
【００１０】
アルコール類としては、例えばメタノール、エタノール。１−プロパノール、２−プロパノール、１−ブタノール、２−ブタノール、イソブチルアルコール、ｔ−ブチルアルコールを挙げることができる。グリコールエーテル類としては、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノイソプロピルエーテル、エチレングリコールモノブチルエーテル、プロピレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、プロピレングリコールモノプロピルエーテルを挙げることができる。
【００１１】
誘導体としては、酢酸メチル、酢酸エチル等のアルコール類の脂肪酸エステル誘導体やプロピノングリコールモノメチルエーテルアセテート等のグリコールエーテル類の脂肪酸エステル誘導体を挙げることができる。
溶解性パラメーターであるｓｐ値が７以下であると、溶媒の極性が非極性側になりすぎ、またｓｐ値が１３以上であると溶媒の極性が高くなりすぎる。これらの領域に位置する有機溶媒中では一般式（１）記載の化合物の溶解状態が大きく変化し、その結果要求される性能を発揮しないため好ましくない。
【００１２】
これらの有機溶媒は、それぞれ単独で用いても二種以上適宜組み合わせて用いても良い。有機溶媒の配合量は、筆記具用インク組成物１００重量部に対して、４０〜９９重量部、好ましくは５０〜９５重量部の範囲から選択される。配合量が４０重量部未満であると、添加される着色剤やその他の成分の相対的な添加量が多くなるため、分散安定性に悪影響を与えると共に、インク組成物の粘度が高くなり筆記性能を低下させるため好ましくなく、９９重量部を越えると着色剤やその他の成分が相対的に不足するために濃度の堅牢性が低下し好ましくない。
【００１３】
本発明で用いられる着色剤は本発明の筆記具用インク組成物を構成する着色成分であり、有機顔料であれば特に限定はされない。具体的にはアゾレーキ顔料、不溶性モノアゾ顔料、不溶性ジスアゾ顔料、縮合アゾ顔料、キレートアゾ顔料、フタロシアニン系顔料、ピロロピロール系顔料、アントラキノン系顔料、ペリレン系顔料、ペリノン系顔料、チオインジゴ顔料、キナクリドン系顔料、ジオキサジン系顔料、イソインドリノン系顔料、キノフタロン系顔料、染め付けレーキ顔料等が挙げられるが、好ましくはアゾ系顔料、ピロロピロール系顔料等の赤色有機顔料が用いられる。
【００１４】
赤色有機顔料の例としては、C.I.Pigment Red 1、同２、同３、同４、同５、同６、同７、同８、同９、同１０、同１２、同１４、同１５、同１７、同１８、同２２、同２３、同３１、同３７、同３８、同４１、同４２、同４８、同４９、同５０、同５２、同５３、同５４、同５７、同５８、同６０、同６３、同６４、同６５、同６６、同６７、同６８、同８１、同８３、同８８、同９０、同１１２、同１１４、同１１５、同１２３、同１３３、同１４４、同１４６、同１４７、同１４９、同１５０、同１５１、同１６６、同１６８、同１７０、同１７１、同１７２、同１７４、同１７５、同１７６、同１７７、同１７８、同１７９、同１８５、同１８７、同１８８、同１８９、同１９０、同１９３、同１９４、同２０２、同２０８、同２０９、同２１４、同２１６、同２２０、同２２１、同２２４、同２４２、同２４３、同２４５、同２４６、同２４７、同２５４等を挙げることが出来る。
【００１５】
これらの着色剤は単独で用いても二種以上を組み合わせて用いても良い。着色剤の配合量は筆記具としての濃度を確保するために必要な量を配合すれば良く、筆記具インク組成物１００重量部に対して０．５〜３０重量部、好ましくは１〜２０重量部の範囲から選択される。０．５重量部以下では筆記具としての濃度が不十分なため好ましくなく、また３０重量部以上ではインクの分散安定性に悪影響を与えると共にインクの粘度が増加し筆記性能の低下をはたすため好ましくない。
【００１６】
本発明で用いられる一般式（１）の構造式を有する化合物は、本発明のインク組成物の分散安定性を維持するために必須の成分であり、単独で用いても二種以上を組み合わせて用いても良い。配合量は着色剤としての有機顔料に対して１００：１〜４：１、好ましくは２０：１〜５：１の重量比の範囲内で用いられる。配合量が１００：１以下だと、化合物の顔料表面への吸着が不十分で、目的とする性能が得られず、また４：１以上だと、化合物がインク組成物中に過剰に存在することとなり、分散安定性に悪影響を及ぼすため好ましくない。
【００１７】
具体的には、以下に示すような物質を挙げることが出来る。
＜化合物例１＞
【化３】

＜化合物例２＞
【化４】

【００１８】
＜化合物例３＞
【化５】

＜化合物例４＞
【化６】

【００１９】
＜化合物例５＞
【化７】

＜化合物例６＞
【化８】

【００２０】
本発明で用いられるカチオン性分散剤は着色剤としての有機顔料の分散性を維持するために必須の成分であり、分散剤の分子内にカチオン性の官能基を有し、有機溶媒中でカチオン性を示すものであれば特に限定はされないが、好ましくは、有機溶媒に幅広い相溶性を示す数平均分子量１０００〜１０００００の分散剤で、分子内に第１級アミン、第２級アミン、第３級アミンを有するものが用いられる。例えば、ビッグケミー社製ＢＹＫ−１６３（ポリカルボン酸のアルキルアミン塩を有するポリマー）や、ゼネカ社製ソルスパース２４０００（ポリエチレンイミンを有するポリマー）等が挙げられる。
【００２１】
これらの分散剤は単独で用いても、二種以上を組み合わせて用いても良い。分散剤の配合量は分散性を維持するのに必要な量を適宜添加して良く、筆記具用インク組成物中の着色剤の重量に対して分散剤の成分量の重量比が２０：１〜１：１、好ましくは１０：１〜２：１の範囲で用いられる。２０：１以下だと、目的とする分散安定性が得られず、また１：１以上だと分散剤がインク組成物中に過剰に存在することになり、インクの経時安定性ら悪影響を及ぼす。また、分散性の向上を目的としてカチオン性の分散剤以外の分散剤も必要に応じて適宜添加しても良い。具体的には、顔料粒子間の立体障害効果を高めるために、例えばポリビニルブチラール等の高分子の樹脂を添加する等の手段が挙げられる。
【００２２】
本発明は着色剤としての有機顔料、一般式（１）の構造を示す化合物、カチオン性の分散剤、及び有機溶媒を必須成分とするが、これ以外の成分で通常の筆記具用インク組成物に用いられる成分も任意に用いることが出来る。
例えば、筆記具用インキ組成物の粘度を調整したり、着色剤の被筆記媒体への定着性や耐水性を向上させるために、通常使用される樹脂を用いてもよく、具体的な例として、ケトン樹脂、スルホアミド樹脂、マレイン酸樹脂、エステルガム、キシレン樹脂、アルキッド樹脂、フェノール樹脂、ロジン、ポリビニルピロリドン、ポリビニルブチラール、ポリビニルアルコール、アクリル系樹脂、メラミン系樹脂、セルロース系樹脂等の天然及び合成樹脂の１種又は２種を用いることができる。
【００２３】
また、樹脂の他、防腐剤、防黴剤、防錆剤、潤滑財、ｐＨ調整剤、粘度調整剤、沈降防止剤、溶解助剤、界面活性剤等の成分も用いることができる。
本発明の筆記具用インキ組成物は、着色剤としての有機顔料、一般式（１）の構造を示す化合物、カチオン性の分散剤、有機溶媒の他、所定の成分を公知の種々の筆記具用インキ組成物の製造方法により製造することができる。
【００２４】
例えば、混合撹拌機により各成分を均一に分散する方法や、ボールミル、ビーズミル、ロールミル、ホモミキサー、ディスパー、超音波撹拌機、高圧ホモジナイザー等の分散機を用いて各成分を分散混合する方法により製造することができる。このとき、全成分を同時に撹拌混合あるいは分散混合しても、必須成分のみを撹拌混合あるいは分散混合した後で、その他の成分を順次撹拌混合あるいは分散混合してもかまわない。また、顔料合成段階で顔料と一般式（１）で示される化合物を混合したり、顔料表面へ一般式（１）で示される化合物を表面処理した顔料を用いてもかまわない。
【００２５】
以上述べたように、本発明の筆記具用インキ組成物は着色剤としての有機顔料、一般式（１）で示される化合物、カチオン性の分散剤を有機溶媒中で筆記具用インク組成物の製造方法として、種々の公知の手段を用いて分散することにより、分散安定性の極めて高い筆記具用インク組成物を完成するに至ったというものである。なお本発明の筆記具用インキ組成物は、ボールペン、万年筆、サインペン、マーキングペン等に好適に使用できる。
【００２６】
【実施例】
以下に本発明の実施例、比較例及び試験例を挙げて本発明を更に詳細に説明するが、本発明は実施例によって何ら限定されるものではない。但し、配合の部は重量部である。
【００２７】
実施例１
下記の配合成分を混合し、ビーズミルにて分散してインキ組成物を得た。
・着色剤：クロモフタノールＤＰＰレッド
（チバスペシャリテイケミカルズ製) ５．０部
・化合物例１の構造を有する化合物 ０．５部
・分散剤：BYK163（ビックケミー社製） ５．０部
・溶媒 ：プロピレングリコールモノメチルエーテル ８９．５部
【００２８】
実施例２
下記の配合成分を混合し、ビーズミルにて分散してインキ組成物を得た。
・着色剤：Symular Fast Red 4582（ＤＩＣ製） ５．０部
・化合物例２の構造を有する化合物 ０．５部
・分散剤：Solsperse24000（ゼネカ社製） ２．５部
・溶媒 ：プロピレングリコールモノメチルエーテル ９２．０部
【００２９】
比較例１
下記の配合成分を混合し、ビーズミルにて分散してインキ組成物を得た。
・着色剤：Symular Fast Red 4582（ＤＩＣ製） ５．０部
・分散剤：Solsperse24000（ゼネカ社製） ２．５部
・溶媒 ：プロピレングリコールモノメチルエーテル ９２．０部
【００３０】
比較例２
下記の配合成分を混合し、ビーズミルにて分散してインキ組成物を得た。
・着色剤：Symular Fast Red 4582（ＤＩＣ製） ５．０部
・顔料誘導体：Solsperse22000 ０．５部
（ゼネカ社製：ジスアゾイエローの誘導体）
・分散剤：Solsperse24000（ゼネカ社製） ２．５部
・溶媒 ：プロピレングリコールモノメチルエーテル ９２．０部
【００３１】
上記した実施例１〜２及び比較例１〜２で調整した筆記具用インキ組成物の流動性を観察し、濾紙上にインクを滴下して分散状態を観察した。またインク組成物をガラス瓶に保管して１ケ月後の分散安定性を再度濾紙上で確認した。その評価結果を表１に示す。
【００３２】
【表１】

【００３３】
【発明の効果】
以上説明したように本発明の筆記具用インク組成物は、油性マーカー等の有機溶媒を用いた筆記具において、分散性と経時安定性に優れた顔料インクを出来る点に顕著な効果を奏するものである。[0001]
[Industrial application fields]
The present invention relates to a writing ink composition using an organic pigment as a colorant. More specifically, the present invention relates to an ink composition for a writing instrument that is extremely excellent in dispersibility and temporal stability of a pigment as a colorant.
[0002]
[Prior art]
In recent years, in inks for writing instruments containing organic solvents, it has been desired to reduce the harm of organic solvents, and many writing instruments that use alcohol-based or glycol-based solvents with relatively low toxicity among organic solvents have been marketed. Yes. On the other hand, pigment-based inks having excellent water resistance and light resistance have been mainly used as coloring agents for writing instruments from conventional dye systems. Many organic pigments are used as colorants for pigment-based inks. When these pigments are dispersed in an organic solvent, a dispersing agent such as a polymer or an activator is usually used. However, the surface of the organic pigment is generally inactive, and satisfactory dispersion is often not obtained.
[0003]
Actually, the pigment surface is subjected to various treatments depending on its use.
In addition to oxidation treatment, rosin treatment, and various activator treatments, the pigment surface can be treated with compounds having a structure close to that of a pigment and various functional groups introduced according to the purpose. Means for surface modification by adsorbing on the pigment surface have been studied. When selecting a pigment for writing instrument ink, it is necessary to select a pigment having a hue suitable for the writing instrument ink. Further, when the pigment ink causes pigment precipitation, the pen tip is clogged, resulting in poor writing. For this reason, it is necessary to make the pigment fine, and it is necessary to perform an appropriate surface treatment so as to have a strong affinity with the dispersant in order to make the pigment fine.
[0004]
[Problems to be solved by the invention]
However, in reality, a material that satisfies the performance required as an ink composition for writing instruments is not necessarily obtained.
This invention solves the subject of the ink for writing instruments as mentioned above, and provides the ink composition for writing instruments excellent in the dispersibility of a pigment and temporal stability.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventor has added an organic pigment and a compound having a specific structure in an organic solvent having a solubility parameter sp value in the range of 7 to 13. The present inventors have found that an ink composition dispersed by adding a cationic dispersant and a writing instrument using the ink composition solve the above problems, and have completed the present invention.
[0006]
That is, the ink composition for a writing instrument of the present invention is
(1) An ink composition for a writing instrument containing an organic pigment, a cationic dispersant, and an organic solvent contains a compound represented by the following general formula (1).
[Chemical formula 2]

(In the formula, X is a phenylene group, or an alkyl group substituted with 1 to 3 carbon atoms, an alkoxy group substituted with 1 to 3 carbon atoms, a halogen substituted or a nitro group substituted phenylene group. There, Y is a phenyl group, or alkyl group substituted ranging from 1 to 3 carbon atoms, alkoxy groups substituted in the range of 1 to 3 carbon atoms, halogen-substituted, a nitro group-substituted phenyl group, Z is is -SO ₃ H or -COOH.)
[0007]
(2) In the present invention, the organic pigment is a red pigment.
(3) The compounding ratio of the compound having the structure (1) with respect to the organic pigment is 100: 1 to 4: 1.
(4) The present invention provides an ink composition having an sp value of 7 to 13 which is a solubility parameter of an organic solvent.
[0008]
The compound having the structure represented by the general formula (1) used in the present invention is an essential component for the ink composition of the present invention, and plays a large role in the dispersion stability of the pigment as a colorant. The mechanism of action is not clear, but is considered as follows.
The compound having the structure represented by the general formula (1) is adsorbed on the surface of the organic pigment by the action of hydrophobic interaction or the like, and is further active in the molecule of the compound of the general formula (1) adsorbed on the surface of the organic pigment. It is considered that the organic pigment is well dispersed in the organic solvent because the functional group has an affinity with the cationic dispersant.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
The organic solvent used in the present invention is not particularly limited as long as it is an organic solvent used in a normal writing instrument within the scope of the claims, but preferably has a sp value of 7 to 13 as a solubility parameter. An organic solvent exhibiting a value is used.
Specific examples include alcohols, glycols, glycol ethers, fatty acid esters, ketones, ethers, aliphatic hydrocarbons, aromatic hydrocarbons and derivatives thereof, preferably alcohols, Examples thereof include glycol ethers and derivatives thereof.
[0010]
Examples of alcohols include methanol and ethanol. Examples include 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, and t-butyl alcohol. Examples of glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monopropyl ether.
[0011]
Examples of the derivatives include fatty acid ester derivatives of alcohols such as methyl acetate and ethyl acetate, and fatty acid ester derivatives of glycol ethers such as propynone glycol monomethyl ether acetate.
When the sp value, which is a solubility parameter, is 7 or less, the polarity of the solvent becomes too nonpolar, and when the sp value is 13 or more, the polarity of the solvent becomes too high. In the organic solvent located in these regions, the dissolved state of the compound described in the general formula (1) changes greatly, and as a result, the required performance is not exhibited, which is not preferable.
[0012]
These organic solvents may be used alone or in combination of two or more. The blending amount of the organic solvent is selected from the range of 40 to 99 parts by weight, preferably 50 to 95 parts by weight, with respect to 100 parts by weight of the ink composition for writing instruments. When the blending amount is less than 40 parts by weight, the relative addition amount of the colorant and other components to be added increases, so that the dispersion stability is adversely affected and the viscosity of the ink composition is increased, so that the writing performance is increased. When the amount exceeds 99 parts by weight, the colorant and other components are relatively insufficient, and the fastness of the concentration is lowered.
[0013]
The colorant used in the present invention is a coloring component constituting the ink composition for a writing instrument of the present invention, and is not particularly limited as long as it is an organic pigment. Specifically, azo lake pigments, insoluble monoazo pigments, insoluble disazo pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, pyrrolopyrrole pigments, anthraquinone pigments, perylene pigments, perinone pigments, thioindigo pigments, quinacridone pigments, Examples thereof include dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dyed lake pigments, and red organic pigments such as azo pigments and pyrrolopyrrole pigments are preferably used.
[0014]
Examples of red organic pigments include CIPigment Red 1, 2, 3, 4, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 17 , 18, 22, 23, 31, 37, 38, 41, 42, 48, 49, 50, 52, 53, 54, 57, 58, the same 60, 63, 64, 65, 66, 67, 68, 81, 83, 88, 90, 112, 114, 115, 123, 133, 144, 146, 147, 149, 150, 151, 166, 168, 170, 171, 172, 174, 175, 176, 177, 178, 179, 185 187, 188, 189, 190, 193, 194, 202, 208, 209, 2 4, the 216, the 220, the 221, the 224, the 242, the 243, the 245, the 246, the 247, can be mentioned the 254 like.
[0015]
These colorants may be used alone or in combination of two or more. The blending amount of the colorant may be an amount necessary to ensure the concentration as a writing instrument, and is 0.5 to 30 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the writing instrument ink composition. Selected from a range. Less than 0.5 parts by weight is not preferable because the concentration as a writing instrument is insufficient, and more than 30 parts by weight is not preferable because it adversely affects the dispersion stability of the ink and increases the viscosity of the ink, thereby reducing the writing performance. .
[0016]
The compound having the structural formula of the general formula (1) used in the present invention is an essential component for maintaining the dispersion stability of the ink composition of the present invention, and may be used alone or in combination of two or more. It may be used. The blending amount is 100: 1 to 4: 1, preferably 20: 1 to 5: 1 with respect to the organic pigment as the colorant. If the blending amount is 100: 1 or less, the adsorption of the compound onto the pigment surface is insufficient, and the desired performance cannot be obtained. If the blending amount is 4: 1 or more, the compound is excessively present in the ink composition. This is not preferable because it adversely affects the dispersion stability.
[0017]
Specifically, the following substances can be listed.
<Compound Example 1>
[Chemical 3]

<Compound Example 2>
[Formula 4]

[0018]
<Compound Example 3>
[Chemical formula 5]

<Compound Example 4>
[Chemical 6]

[0019]
<Compound Example 5>
[Chemical 7]

<Compound Example 6>
[Chemical 8]

[0020]
The cationic dispersant used in the present invention is an essential component for maintaining the dispersibility of the organic pigment as the colorant, has a cationic functional group in the molecule of the dispersant, and is cationic in an organic solvent. However, it is preferably a dispersant having a number average molecular weight of 1,000 to 100,000, which is widely compatible with an organic solvent, and has a primary amine, a secondary amine, a third amine in the molecule. Those having a secondary amine are used. Examples thereof include BYK-163 (polymer having an alkylamine salt of polycarboxylic acid) manufactured by Big Chemie, Solsperse 24000 (polymer having polyethyleneimine) manufactured by Zeneca.
[0021]
These dispersants may be used alone or in combination of two or more. The amount of the dispersing agent may be appropriately added to maintain the dispersibility, and the weight ratio of the component amount of the dispersing agent to the weight of the colorant in the ink composition for writing instruments is 20: 1 to 1. It is used in a range of 1: 1, preferably 10: 1 to 2: 1. If it is 20: 1 or less, the desired dispersion stability cannot be obtained, and if it is 1: 1 or more, the dispersant is excessively present in the ink composition, which adversely affects the aging stability of the ink. . Further, for the purpose of improving the dispersibility, a dispersant other than the cationic dispersant may be appropriately added as necessary. Specifically, in order to enhance the steric hindrance effect between the pigment particles, for example, means such as adding a polymer resin such as polyvinyl butyral can be used.
[0022]
In the present invention, an organic pigment as a colorant, a compound having a structure represented by the general formula (1), a cationic dispersant, and an organic solvent are essential components. The components used can also be used arbitrarily.
For example, in order to adjust the viscosity of the ink composition for writing instruments, or to improve the fixability and water resistance of the coloring agent to the writing medium, a commonly used resin may be used. As a specific example, Natural and synthetic resins such as ketone resins, sulfoamide resins, maleic resins, ester gums, xylene resins, alkyd resins, phenol resins, rosin, polyvinyl pyrrolidone, polyvinyl butyral, polyvinyl alcohol, acrylic resins, melamine resins, and cellulose resins 1 type or 2 types of can be used.
[0023]
In addition to resins, components such as preservatives, antifungal agents, rust preventives, lubricants, pH adjusters, viscosity adjusters, antisettling agents, dissolution aids, and surfactants can also be used.
The ink composition for a writing instrument according to the present invention includes various known inks for writing instruments, in addition to an organic pigment as a colorant, a compound having the structure of the general formula (1), a cationic dispersant, an organic solvent, and a predetermined component. It can manufacture with the manufacturing method of a composition.
[0024]
For example, manufactured by a method in which each component is uniformly dispersed with a mixing stirrer, or a method in which each component is dispersed and mixed using a dispersing machine such as a ball mill, a bead mill, a roll mill, a homomixer, a disper, an ultrasonic stirrer, or a high-pressure homogenizer. can do. At this time, all the components may be stirred and dispersed or mixed at the same time, or only the essential components may be stirred and mixed or dispersed, and then the other components may be stirred and mixed or dispersed. Further, a pigment and a compound represented by the general formula (1) may be mixed in the pigment synthesis stage, or a pigment obtained by surface-treating the compound represented by the general formula (1) on the pigment surface may be used.
[0025]
As described above, the ink composition for a writing instrument according to the present invention is a method for producing an ink composition for a writing instrument in an organic solvent containing an organic pigment as a colorant, a compound represented by the general formula (1), and a cationic dispersant. As described above, by dispersing using various known means, an ink composition for writing instruments having extremely high dispersion stability has been completed. In addition, the ink composition for writing instruments of this invention can be used conveniently for a ball-point pen, a fountain pen, a sign pen, a marking pen, etc.
[0026]
【Example】
EXAMPLES The present invention will be described in more detail below with reference to examples, comparative examples, and test examples of the present invention, but the present invention is not limited to the examples. However, the blending part is part by weight.
[0027]
Example 1
The following blending components were mixed and dispersed with a bead mill to obtain an ink composition.
Coloring agent: Chromophthalol DPP Red (manufactured by Ciba Specialty Chemicals) 5.0 parts Compound 0.5 having the structure of Compound Example 1 Dispersant: BYK163 (manufactured by Big Chemie) 5.0 parts Solvent: Propylene glycol monomethyl ether 89.5 parts
Example 2
The following blending components were mixed and dispersed with a bead mill to obtain an ink composition.
Colorant: Symbolic Fast Red 4582 (made by DIC) 5.0 parts Compound 0.5 having the structure of Compound Example 2 Dispersant: Solsperse 24000 (made by Zeneca) 2.5 parts Solvent: Propylene glycol monomethyl ether 92.0 parts [0029]
Comparative Example 1
The following blending components were mixed and dispersed with a bead mill to obtain an ink composition.
Coloring agent: Symular Fast Red 4582 (manufactured by DIC) 5.0 parts Dispersant: Solsperse 24000 (manufactured by Zeneca) 2.5 parts Solvent: propylene glycol monomethyl ether 92.0 parts
Comparative Example 2
The following blending components were mixed and dispersed with a bead mill to obtain an ink composition.
Colorant: Symular Fast Red 4582 (manufactured by DIC) 5.0 parts Pigment derivative: Solsperse 22000 0.5 part (manufactured by Zeneca: Disazo Yellow derivative)
Dispersant: Solsperse 24000 (manufactured by Zeneca) 2.5 parts Solvent: propylene glycol monomethyl ether 92.0 parts
The fluidity of the ink compositions for writing instruments prepared in Examples 1 and 2 and Comparative Examples 1 and 2 described above was observed, and ink was dropped on the filter paper to observe the dispersion state. The ink composition was stored in a glass bottle, and the dispersion stability after one month was confirmed again on the filter paper. The evaluation results are shown in Table 1.
[0032]
[Table 1]

[0033]
【The invention's effect】
As described above, the ink composition for a writing instrument of the present invention has a remarkable effect in that a pigment ink having excellent dispersibility and stability over time can be produced in a writing instrument using an organic solvent such as an oil marker. .

Claims (4)

An ink composition for a writing instrument comprising an organic pigment, a cationic dispersant and an organic solvent, comprising a compound represented by the following general formula (1):

(In the formula, X is a phenylene group, or an alkyl group substituted with 1 to 3 carbon atoms, an alkoxy group substituted with 1 to 3 carbon atoms, a halogen substituted or a nitro group substituted phenylene group. There, Y is a phenyl group, or alkyl group substituted ranging from 1 to 3 carbon atoms, alkoxy groups substituted in the range of 1 to 3 carbon atoms, halogen-substituted, a nitro group-substituted phenyl group, Z is is -SO ₃ H or -COOH.)   The ink composition for a writing instrument according to claim 1, wherein the organic pigment is a red pigment.   The ink composition for a writing instrument according to claim 1 or 2, wherein the compounding ratio of the compound having the structure (1) to the organic pigment is 100: 1 to 4: 1. The ink composition for a writing instrument according to any one of claims 1 to 3 , wherein the solubility parameter of the organic solvent has an sp value of 7 to 13.