JP4668388B2 - Water-based ink for inkjet printing - Google Patents

Description

【００１４】
（式中，Ｒ₁〜Ｒ₃は，Ｃ₂Ｈ₅，ＣＨ₂Ｃ₆Ｈ₅，ＣＨ₂ＣＨ₂Ｃ₆Ｈ₅，ＣＨ（ＣＨ₃）Ｃ₆Ｈ₅の中からの何れかを表し、
Ｌは、Ｈ，又はＳＯ_３Ｍを表し、
Ｍは、Ｋ，Ｎａ，ＮＨ₄，Ｈ，及び炭素数５以下のアルキル基，アルカノール基を有するアルキルアミン，アルカノールアミンの何れかを表し、
ｍは９〜３０の整数を表す。）
【００１５】
【化４】

【００１６】
（式中、Ｒ_４〜Ｒ_５はＣＨ_３，Ｃ_２Ｈ_５の中からの何れかを表し、
ｎは１〜１０の整数を表す。）
【００１７】
そして、〔２〕、前記インクジェット捺染用水性インクに対する水性染料の濃度をＸ重量％、界面活性剤の濃度をＹ重量％、およびジアルキルエーテル類の濃度をＺ重量％としたとき、
Ｙ＝ａＸ
（式中、ａは０．０１〜１を表す。）
および、
Ｚ＝ｂ／Ｙ
（式中、ｂは０．１〜０．５を表す。）
を満足する上記〔１〕のインクジェット捺染用水性インクに存する。
【００１８】
そしてまた、〔３〕、前記インクジェット捺染用水性インクに対して、水性染料が０．０１〜２０重量％である上記〔１〕〜〔２〕のインクジェット捺染用水性インクに存する。
【００１９】
そしてまた、〔４〕、前記インクジェット捺染用水性インクに対して、界面活性剤が０．０１〜５重量％である上記〔１〕〜〔３〕のインクジェット捺染用水性インクに存する。
【００２０】
そしてまた、〔５〕、前記インクジェット捺染用水性インクに対して、ジアルキルエーテル類が０．１〜５重量％である上記〔１〕〜〔４〕のインクジェット捺染用水性インクに存する。
【００２１】
そしてまた、〔６〕、前記水性染料が、酸性染料である上記〔１〕〜〔５〕記載のインクジェット捺染用水性インクに存する。
【００２２】
【発明の実施の形態】
本発明のインクは、ヘッドの圧力室内でのキャビテーションによる気泡発生を抑制する効果があり、またインクジェット印写される常温にてインク中の染料の溶解状態は変化せず、且つ布帛への浸透性も適度であり、粘度も低く安定し、加えるに表面張力、ｐＨ等の物性変化もない。
インクジェット捺染では、多様な色柄を表現するために、同一染料で濃度の異なる数種類のインクを準備して使用することが良く行われている。
特に淡色を表現する際に、高濃度インクを使用するより、低濃度インクを使用する方が、当然表現し易く、品質の満足出来る染色物を得ることが可能である。
その際、どの様な濃度段階であっても、本発明の一般式（１）で示される界面活性剤と一般式（２）で示されるジアルキルエ−テル類を併用することにより、キャビテ−ション、溶解安定性、吐出安定性、布帛への浸透性を満足させることが可能となり、極めて有効である。
【００２３】
例えば、ある水性染料を、溶解安定剤として本発明の一般式（１）で示される界面活性剤を用いて、その染料で可能な最高濃度水性インクを得たとする。
しかし、淡色を表現するために、その１／５濃度のインクが必要になったとする。
その場合、最高濃度インクを純水を使用し１／５濃度に希釈調整する。
その１／５濃度に調整されたインクは当然、染料の濃度も１／５濃度になり、キャビテ−ション防止という効果がかなり低下してしまう。
しかし、希釈調整の際に一般式（２）で示されるエチレングリコ−ルジアルキルエ−テル類の濃度を逆に高くすることにより、キャビテ−ション防止効果がより一層増加し、さらにインク粘度、表面張力や布帛への浸透性には影響が少なく、極めて有効である。
従って、長時間連続してインクジェット印写することが可能となり、且つ品質良好な染色物を得る事が出来る。
本発明の上記一般式（１）で表される界面活性剤は、公知の方法、例えば、特公昭４６ー２７７９１号公報、特開平７ー２２８６３号公報に開示される方法やそれに準ずる方法にて製造される。
【００２４】
本発明のインク、すわなわちインクジェット捺染用水性インクは、上記一般式（１）で示される界面活性剤から選ばれた単独あるいは２種以上の組み合わせで使用され、上記一般式（２）で示されるジアルキルエ−テル類と併用することで効果を発揮する。
本発明のインクジェット捺染用水性インクに対する界面活性剤の含有量は０．０１〜５重量％であり、好ましくは０．０１〜３重量％である。
界面活性剤が０．０１重量％より少ないと目的の長期保存効果が十分得られず、５重量％より多いと染料の布帛への浸透が大きくなり滲みや裏抜け等の欠点が多くなる。
【００２５】
本発明のインクジェット捺染用水性インクに対する水性染料の含有量は、０．０１〜２０重量％、望ましくは０．０１〜１０重量％である。
水性染料が０．０１重量％より少ないと溶解安定性の問題が起こりにくくなるが、逆にキャビテーションが発生しやすくなり、２０重量％より多くなると、染料の溶解限度を越えインクそのものの調製が困難となる。
【００２６】
本発明のインクジェット捺染用水性インクに対する、上記一般式（２）で示されるジアルキルエ−テル類の含有量は、０．１〜５重量％であり、好ましくは０．１〜３重量％、より好ましくは０．１〜２重量％である。
ジアルキルエ−テル類が０．１重量％より少ないと、キャビテ−ション防止効果が不十分となり、５重量％添加すれば、十分効果を得ることが可能なことから、それ以上の添加は無意味であり、コスト高となる。
本発明の一般式（２）で表されるジアルキルエーテル類は公知の方法、例えばメタノールあるいはエタノールとエチレンオキサイド等とを反応させることにより容易に製造される。
本発明で使用される水溶性染料は、特定されるものではなく、公知の反応染料、酸性染料、１：１型金属錯塩染料、１：２型金属錯塩染料、直接染料等いずれも使用できるが、インクジェット用インクを調製する場合に比較的溶解しにくく本発明により溶解安定性に対し特に優れた効果が得られる酸性染料が好ましい。
【００２７】
そして、反応染料の種類としては、ピラゾロンアゾ系、ベンゼンアゾ系、ナフタレンアゾ系、ピリドンアゾ系、Ｊ酸アゾ系、Ｈ酸アゾ系、Ｋ酸アゾ系、アントラキノン系、金属錯塩型モノアゾ系、ホルマザン系、フタロシアニン系、ジスアゾ系、アジン系、ジオキサジン系等が、また反応染料反応基別としては、ビニルスルホン型、ジクロロトリアジン型、モノクロロトリアジン型、モノフロロトリアジン型、トリクロロピリミジン型、ビニルスルホン＋モノクロロトリアジン型等が挙げられる。
【００２８】
酸性染料の種類としては、ベンゼンアゾやピラゾロンアゾといったモノアゾ系、キニザリンやブロマミンといったといったアントラキノン系の他に、ポリアゾ系、トリアリルメタン系、キサンテン系、ニトロ系が挙げられる。
その他に、クロム染料、塩基性染料、蛍光染料等も使用できる。
以上の水溶性染料は単独、あるいは２種以上の組み合わせで使用できる。
【００２９】
インクジェット捺染用水性インクに対する添加剤として、必要に応じて、湿潤剤、ｐＨ調整剤、キレート剤、電気伝導度調整剤、紫外線吸収剤、赤外線吸収剤等が添加される。
通常、添加剤の含有量は、０．１重量％〜１０重量％程度である。
【００３０】
湿潤剤としては、ヒドロキシプロピル−β−シクロデキストリン、トリメチロ−ルエタン、トリメチロ−ルプロパン、カプロラクタム、尿素等の他にペントース、ヘキトース等の単糖類、二糖類、三糖類といった多糖類、あるいはこれらの誘導体である糖アルコール、デキオシ酸といった還元誘導体、アルドン酸、ウロン酸といった酸化誘導体、脱水誘導体、アミノ酸、チオ糖類等の固体湿潤剤とエチレングリコール、ジエチレングリコール、ポリエチレングリコール、プロピレングリコール、ジプロピレングリコール、ポリプロピレングリコール、トリエチレングリコール、ヘキシレングリコール、テトラエチレングリコール、グリセリン、１，３−ブタンジオール、１，５−ペンタジオール、１，２，６−ヘキサントリオール等の高沸点低揮発性を有する多価アルコール化合物等の液体湿潤剤が挙げられる。
【００３１】
ｐＨ調整剤としては、ジエタノールアミン、トリエタノールアミン等の有機アミン、水酸化ナトリウム、水酸化カリウム、リン酸水素カリウム等の無機塩基、酒石酸、乳酸、フタル酸、酢酸、ギ酸等の有機酸や硫酸、ショウ酸等の鉱酸が挙げられる。
【００３２】
防腐剤としては、Ｏ−フェニルフェノールナトリウム、ホルマリン、ｐ−ヒドロキシ安息香酸メチル、Ｎａ−２−ピリジンチオール−１−オキシド、ヘキサヒドロ−１，３，５−トリス−ｓ−トリアジン、テトラクロルイソフタロニトリル、Ｚｎ−２−ピリジンチオール−１−オキシドの他に、５−クロル−２−メチル−４−イソチアゾリン−３−オン、２−オクチル−４−イソチアゾ−３−オン、１，２−ベンズイソチアゾリン等のイソチアゾリン系化合物等が挙げられる。
【００３３】
キレート剤としては、ＥＤＴＡ、アクリル酸系化合物、ポリカルボン酸系化合物、リン系化合物等が挙げられる。
【００３４】
本発明のインクジェット捺染用水性インクは、上記の水性染料、上記一般式（１）で示される界面活性剤、および上記一般式（２）で示されるジアルキルエ−テル類とを混合させ、通常、６０℃以上の純水を添加し３０分間攪拌した後、２５℃（室温）まで冷却しその水溶液を濾過することにより得られる。
インクジェット印字する色柄によって、低濃度インクが必要とされる場合は、上述で作成したインクを純水にて希釈調整すれば良いが、その時に上記一般式（１）で示される界面活性剤を染料濃度に比例させた量、および上記一般式（２）で示されるジアルキルエ−テル類を上記一般式（１）の界面活性剤濃度に反比例させた量を含有させることが好ましい。
本発明のインクを使ったインクジェット印写装置で使用される圧電型ヘッドは既に周知のものであり一例を図１（インク供給路Ａから、圧力室Ｃにインクを満たし、圧電素子Ｄに任意の電力を加え振動板Ｅを変形させ、圧力室Ｃの体積を縮小させ加圧することによって、ノズルＢからインクを飛翔させる）に示す。
因みに、上記ヘッドにおけるキャビテーションとは前記圧力室内の微小な気泡が、気泡周辺の圧力変化によって、膨張することである。
【００３５】
このように圧力室内に膨張した気泡が発生した場合、圧電素子に電圧を加え、振動板を変形させても気泡が収縮するために、ノズルからインクが吐出されない現象、いわゆるキャビテーションによるノズルのエア詰まりが生ずるのである。
以下、本発明について実施例を挙げて説明するが、本発明は、必ずしもその実施例に限定されるものではない。
【００３６】
【実施例】
実施例及び比較例におけるインクの各種物性の試験方法、及びその捺染された布帛の図柄の濃度、鮮明さなどの品位の評価方法は、以下の通りである。
〔使用したインク〕
〔実施例１〕〜〔実施例４〕及び〔比較例１〕〜〔比較例４〕において使用したインクの組成は、別途〔表１〕に示された通りである。
【００３７】
【表１】

【００３８】
また、〔実施例５〕〜〔実施例１０〕及び〔比較例５〕〜〔比較例１０〕において使用したインクの組成は、〔表２〕に示された通りである。
【００３９】
【表２】

【００４０】
いずれのインクも表の成分を配合し８０℃にて３０分間攪拌混合し、室温２５℃まで液温を低下させた後、フィルター（東洋濾紙Ｎｏ５Ａ）にて濾過してインクを調製した。
【００４１】
尚、表１，表２における界面活性剤は、下記の式（Ｉ）〜（ＩＶ）の通りである。
ここで、Ｒ₁はＣ₂Ｈ₅，Ｒ₂はＣＨ₂Ｃ₆Ｈ₅，Ｒ₃はＣＨ（ＣＨ₃）Ｃ₆Ｈ₅である。
【００４２】
【化５】

【００４３】
【化６】

【００４４】
【化７】

【００４５】
【化８】

【００４６】
また、表１，表２におけるジアルキルエーテル類は、下記式（Ｖ）の通りである。
【００４７】
【化９】

【００４８】
〔試験及び評価方法〕
（１）キャビテーションによる気泡発生の確認法
先述した図１のヘッドにインクを注入し、下記の印写条件を与えてインクを連続噴射した。
この連続噴射の直後、ヘッドの各ノズルから同様の印写条件で１ドットを市販のインクジェット専用紙に噴射し、キャビテーションによる気泡発生を原因とするノズル詰まりや液滴の飛翔方向不良を確認した。
尚、キャビテーションによる悪影響を見る現象として、ノズル詰まりや液滴の飛翔方向不良があり、通常、この現象を観察することによりキャビテーション状態が判断可能である。
【００４９】
印写条件；
イ）印加電圧 ： １５０（Ｖ）
ロ）パルス幅 ： １０（μｓ）
ハ）駆動周波数：５０００（Ｈｚ）
ニ）印写時間 ： ６０（ｍｉｎ）
【００５０】
ここで評価は下記４段階で評価した。
○：ノズルの詰まりや飛翔方向不良の問題がない。
△：ノズルの詰まりはないが、飛翔方向不良のノズルがある。
×：一部のノズルで詰まりがある。
××：ほとんどのノズルで詰まりがある。
【００５１】
（２）溶解安定性
調製したインク５００ｇを一週間放置した後、このインク１００ｇを吸引濾過（６００Ｔｏｒｒ）にて、フィルター〔東洋濾紙Ｎｏ．５Ａ（７ミクロン）、ワットマン社製ＧＦ−Ｆ（０．８ミクロン）〕の通過が可能かどうかを判定した。
【００５２】
評価；
ここで評価は下記３段階で評価した。
○：スムーズに通過（残査なし）
△：フィルターを通過するが、やや残査有り
×：フィルター通過不可能
【００５３】
（３）粘度
下記の装置を用いて粘度を測定した。
装置 ：ＢＬ型粘度計〔（株）東京計測器製〕
測定温度 ：２５℃
使用ロータ ：Ｎｏ．１タイプ
ロータ回転数：６０ｒｐｍ
【００５４】
（４）インクジェット印写方法及び印写された捺染布の品位の評価方法
ａ）インクジェット印写方法
オンデマンド方式シリアル走査型インクジェット印写装置を使用し、印写条件はノズル径１００μｍ、駆動電圧１０７Ｖ、周波数５ＫＨｚ、解像度３６０ｄｐｉ、４×４マトリックスとした。
【００５５】
このようなインクジェット印写装置を使って、経糸・緯糸ともにナイロン糸（３０ｄ）使用して織った試験布（タフタ）面上に、下記の図柄を印刷し、６０℃で１０分間乾燥した。
次に、これを１０２℃で２０分間湿熱処理を行って染料を発色固着した後、通常の洗浄処理、乾燥を行い捺染布を得た。
図柄は、（イ）５０×５０ｍｍの四角形、（ロ）幅０．５ｍｍ、長さ５０ｍｍの経緯方向の細線による十字形の２パターンとした。
【００５６】
ｂ）捺染布の品位の評価方法
前記ａ）で得られた捺染布を下記項目について観察評価した。
表面濃度；色差計により（イ）の図柄の表面反射率を測定し、表面濃度をＣＩＥ１９７６Ｌａｂ表色系のＬ値で示した。
にじみ；目視により（ロ）の図柄におけるにじみの程度を下記の通り評価した。
【００５７】
○ ； にじみ無し
△ ； 一部ににじみあり
× ； にじみ強い
【００５８】
以上の１）〜４）の結果を別途〔表３〕に一覧で示す。
【００５９】
【表３】

【００６０】
〔表３〕より、本発明のインクは、特定の界面活性剤およびジアルキルエーテル類が添加されたことで、キャビテーションによる気泡の発生が十分抑制されたことが解かる。
また、本発明の界面活性剤およびジアルキルエーテル類を少量添加することで、インクの溶解度が向上し、常温にまで温度低下しても安定した溶解状態を保持でき、しかも低粘度であることが解る。
従って、本発明のインクでは、キャビテーションによる気泡の発生を抑制することと、更に染料の溶解安定性をも向上させることの両方が可能である。
【００６１】
【発明の効果】
本発明のインクジェット捺染用水性インクによれば、キャビテーションによる気泡の発生を抑制できるため印写前の脱気が不要であり、且つ染料の溶解安定性が良くなる。
更にまた低粘度であるため、吐出安定性が極めて良好である。
結果的に、このようにインクジェット印写装置の生産効率が良くなった。
しかも滲みや裏抜け等の発生も無く、高品位の捺染布帛が得られる。
本発明のインクジェット捺染用水性インクは、染料として市販粉体水性染料を使用した場合、市販染料に含まれる粉塵防止を目的とした鉱物油等を乳化安定化する作用があり、長期的に良好な吐出を得ることができる。
【図面の簡単な説明】
【図１】図１は、インクジェット印写装置における圧電型のヘッドを概略的に示す図である。
【符号の説明】
Ａ…インク供給路
Ｂ…ノズル
Ｃ…圧力室
Ｄ…圧電素子
Ｅ…振動板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water-based ink for ink-jet printing for dyeing a fabric, and more specifically, it does not depend on the dye concentration of the ink, prevents the generation of bubbles due to cavitation during ink-jet printing of the fabric, and dissolves and stabilizes the dye. The present invention relates to a water-based ink for ink-jet textile printing that also improves properties.
[0002]
[Prior art]
In recent years, a printing method using ink jet printing has attracted attention as a technique for dyeing fabrics.
Since printing using ink jet printing is a method in which ink is ejected from a nozzle, it is possible to give a dense pattern to the fabric, and it does not require a large apparatus on a scale and does not pollute the environment. The utility value is extremely high.
However, on the other hand, it has many problems.
[0003]
The first problem is cavitation.
In general, cavitation is a mechanical phenomenon showing expansion and contraction of bubble nuclei generated in a liquid due to a pressure drop in a liquid at a constant temperature.
In a fabric ink jet printing apparatus, a piezoelectric head is mainly used. However, when this type of ink jet printing apparatus is used, the head is in a state of continuous jetting due to pressure change. Cavitation occurs in the pressure chamber.
Such cavitation inevitably accompanies the generation of bubbles, which causes nozzle clogging and must be eliminated as much as possible.
[0004]
In ink jet textile printing, when a light color is expressed, an ink having a low dye concentration is often used to obtain a high-quality dyed product.
In water-based inks composed of water-soluble dyes such as reactive dyes, acid dyes, and direct dyes, it is known that inks with lower dye concentrations are more susceptible to cavitation than inks with higher dye concentrations. Yes.
This is because the dissolved water-soluble dye itself has a cavitation preventing effect.
When diluting a high density ink to a low density ink, it does not depend on the dye concentration of the ink, prevents the generation of bubbles due to cavitation, has a low viscosity and does not bleed on the fabric and do not show through (or pass through). It is important to create ink.
For this reason, various cavitation countermeasures have been tried.
[0005]
In inkjet printing, as a method for suppressing the generation of bubbles due to cavitation or the like, there is a method in which ink is deaerated under reduced pressure.
That is, it is a method for preventing the generation of bubbles during printing by reducing the amount of dissolved gas in the ink as much as possible in advance.
However, this method has a drawback in that the amount of dissolved gas in the ink increases with time and returns to the original when continuously ejected for a long time.
Therefore, the usable time after performing the deaeration process is limited, and in order to prevent this, it is necessary to perform the deaeration process immediately before the injection.
[0006]
However, in ink jet printing, the deaeration process immediately before ink is practically impossible in consideration of the storage space and characteristics of the apparatus.
For this reason, inkjet printing with a piezoelectric head cannot be performed stably continuously for a long time.
As a countermeasure against the generation of bubbles other than the deaeration process, a method of storing the ink in a sealed container and preventing it from coming into contact with the outside air is conceivable, but it is not practical because the container is limited.
[0007]
On the other hand, as a chemical method, a method of adding an oxygen absorbent such as sodium sulfite, sodium bisulfite, potassium sulfite, or ammonium bisulfite to the ink has been developed. However, when an oxygen absorbent is added to the ink, the pH of the ink is increased. However, there is an adverse effect that is extremely biased to alkalinity or acidity.
For this reason, the ink adversely affects the material constituting the head, such as increasing the corrosivity.
As a result, the life of the head is shortened, the long-term storage stability of the ink is lost, and the decomposition of the dye progresses.
[0008]
Next, as a second problem, the ink dissolution stability may be poor.
The dissolution stability refers to the stability of the ink over time such that when the ink is stored, precipitates are deposited and some physical properties such as viscosity change.
As methods for improving the dissolution stability, methods in which ethylene glycol or the like is contained in the ink are known (Japanese Patent Laid-Open Nos. 9-31379, 5-78609, and 3-100080). Gazette, JP-A-57-57760, etc.).
In any case, the effect is not constant depending on the type of dye. Even if the dye can be dissolved stably at a high temperature of about 80 ° C, the high-concentration solution in a state where the temperature is lowered to room temperature is stable for long-term storage. There are many things lacking in nature.
In addition, it is accompanied by changes in ink physical properties such as increased viscosity and decreased surface tension, and the penetrating power to the fabric is excessively increased, which causes problems such as bleeding and decreased density, and it is difficult to obtain a dyed product with satisfactory quality. Become.
[0009]
As described above, a number of methods for suppressing the generation of bubbles due to cavitation or a method for improving dissolution stability have been studied. However, the method does not depend on the concentration of the dye in the ink, satisfies both of them, and discharge properties. A technology that is satisfactory and satisfactory in dyeing quality has not yet been developed.
It is extremely important to satisfy all of these requirements for inkjet inks for textile printing.
[0010]
[Problems to be solved by the invention]
The present invention has been made against the background of the above technical problems.
That is, an object of the present invention is to suppress the generation of bubbles due to cavitation in the head pressure chamber without depending on the dye concentration of the ink, and to surely improve the dissolution stability of the dye, and to obtain a dyed product with good quality. An object of the present invention is to provide a water-based ink for inkjet textile printing that can be obtained.
[0011]
[Means for Solving the Problems]
As a result of diligent research to solve the above problems, the present inventors have selected a special one from many surfactants, and that the problem can be solved by using in combination with specific dialkyl ethers. The present invention was completed based on the finding and this finding.
[0012]
That is, the present invention is a water-based ink for inkjet printing comprising [1], an aqueous dye, a surfactant represented by the following general formula (1), and a dialkyl ether represented by the following general formula (2). ,
When the water-based dye concentration relative to the water-based ink for inkjet printing is X wt%, the surfactant concentration is Y wt%, and the dialkyl ether concentration is Z wt%,
Y = aX
(In the formula, a represents 0.01 to 1.)
and,
Z = b / Y
(In the formula, b represents 0.1 to 0.6.)
Ink-jet printing ink satisfying the above.
[0013]
[Chemical 3]

[0014]
(Wherein R _{1 to} R ₃ represent any one of C ₂ H ₅ , CH ₂ C ₆ H ₅ , CH ₂ CH ₂ C ₆ H ₅ , and CH (CH ₃ ) C ₆ H ₅ ;
L represents H or SO ₃ M;
M represents K, Na, NH ₄ , H, and an alkyl group having 5 or less carbon atoms, an alkylamine having an alkanol group, or an alkanolamine;
m represents an integer of 9 to 30. )
[0015]
[Formula 4]

[0016]
(In the formula, R _{4 to} R ₅ represent any one of CH ₃ and C ₂ H ₅ ,
n represents an integer of 1 to 10. )
[0017]
[2] When the concentration of the aqueous dye relative to the water-based ink for inkjet printing is X wt%, the concentration of the surfactant is Y wt%, and the concentration of the dialkyl ether is Z wt%,
Y = aX
(In the formula, a represents 0.01 to 1.)
and,
Z = b / Y
(In the formula, b represents 0.1 to 0.5.)
The water-based ink for inkjet printing according to the above [1] satisfying the above.
[0018]
[3] The water-based ink for ink-jet printing according to the above [1] to [2], wherein the water-based dye is 0.01 to 20% by weight with respect to the water-based ink for ink-jet printing.
[0019]
[4] The water-based ink for ink-jet printing according to the above [1] to [3], wherein the surfactant is 0.01 to 5% by weight with respect to the water-based ink for ink-jet printing.
[0020]
[5] The inkjet printing water-based ink according to the above [1] to [4], wherein the dialkyl ether is 0.1 to 5% by weight with respect to the inkjet printing water-based ink.
[0021]
[6] The water-based dye for ink-jet printing according to the above [1] to [5], wherein the water-based dye is an acid dye.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
The ink of the present invention has the effect of suppressing the generation of bubbles due to cavitation in the pressure chamber of the head, and the dissolved state of the dye in the ink does not change at room temperature for ink jet printing, and the permeability to the fabric The viscosity is also low and stable, and in addition, there is no change in physical properties such as surface tension and pH.
In ink-jet textile printing, in order to express a variety of color patterns, it is often performed to prepare and use several types of inks having the same dye and different densities.
In particular, when expressing light colors, it is natural to use low-density ink rather than using high-density ink, and it is possible to obtain a dyed product that is easy to express and satisfies the quality.
At that time, by using the surfactant represented by the general formula (1) and the dialkyl ether represented by the general formula (2) in combination at any concentration step, cavitation, It is possible to satisfy dissolution stability, ejection stability, and permeability to the fabric, which is extremely effective.
[0023]
For example, it is assumed that a water-based ink having the highest concentration possible with a certain aqueous dye is obtained by using the surfactant represented by the general formula (1) of the present invention as a dissolution stabilizer.
However, in order to express a light color, it is assumed that 1/5 density ink is required.
In that case, the highest density ink is diluted and adjusted to 1/5 density using pure water.
Naturally, the ink adjusted to 1/5 density also has a dye density of 1/5, which significantly reduces the effect of preventing cavitation.
However, by increasing the concentration of the ethylene glycol dialkyl ether represented by the general formula (2) at the time of dilution adjustment, the cavitation prevention effect is further increased, and the ink viscosity, surface tension, There is little influence on the permeability to the fabric and it is extremely effective.
Therefore, ink jet printing can be performed continuously for a long time, and a dyed product with good quality can be obtained.
The surfactant represented by the above general formula (1) of the present invention can be obtained by a known method, for example, the method disclosed in Japanese Patent Publication No. 46-27791 and Japanese Patent Laid-Open No. 7-22863, or a method analogous thereto. Manufactured.
[0024]
The ink of the present invention, that is, the water-based ink for inkjet printing, is used alone or in combination of two or more selected from the surfactant represented by the general formula (1), and is represented by the general formula (2). This is effective when used in combination with dialkyl ethers.
The content of the surfactant in the water-based ink for inkjet printing of the present invention is 0.01 to 5% by weight, preferably 0.01 to 3% by weight.
If the surfactant is less than 0.01% by weight, the desired long-term storage effect cannot be obtained sufficiently. If the surfactant is more than 5% by weight, the penetration of the dye into the fabric increases, resulting in increased defects such as bleeding and back-through.
[0025]
The content of the aqueous dye in the aqueous ink for inkjet printing of the present invention is 0.01 to 20% by weight, desirably 0.01 to 10% by weight.
If the amount of water-based dye is less than 0.01% by weight, the problem of dissolution stability is less likely to occur, but conversely, cavitation tends to occur, and if it exceeds 20% by weight, the dye solubility limit is exceeded and it is difficult to prepare the ink itself. It becomes.
[0026]
The content of the dialkyl ether represented by the general formula (2) in the water-based ink for inkjet printing of the present invention is 0.1 to 5% by weight, preferably 0.1 to 3% by weight, and more preferably. Is 0.1 to 2% by weight.
If the amount of dialkyl ether is less than 0.1% by weight, the anti-cavitation effect is insufficient, and if 5% by weight is added, a sufficient effect can be obtained. Yes, the cost is high.
The dialkyl ethers represented by the general formula (2) of the present invention are easily produced by a known method, for example, by reacting methanol or ethanol with ethylene oxide or the like.
The water-soluble dye used in the present invention is not specified, and any of known reactive dyes, acidic dyes, 1: 1 type metal complex dyes, 1: 2 type metal complex dyes, and direct dyes can be used. In the case of preparing an ink jet ink, an acid dye that is relatively difficult to dissolve and can provide a particularly excellent effect on dissolution stability according to the present invention is preferred.
[0027]
The types of reactive dyes are pyrazolone azo, benzene azo, naphthalene azo, pyridone azo, J acid azo, H acid azo, K acid azo, anthraquinone, metal complex monoazo, formazan, Phthalocyanine type, disazo type, azine type, dioxazine type, etc., and reactive dye reactive groups are vinyl sulfone type, dichloro triazine type, monochloro triazine type, monofluoro triazine type, trichloro pyrimidine type, vinyl sulfone + monochloro triazine type Etc.
[0028]
Examples of the acid dye include monoazo series such as benzeneazo and pyrazolone azo, anthraquinone series such as quinizarin and bromamine, and polyazo series, triallylmethane series, xanthene series and nitro series.
In addition, chromium dyes, basic dyes, fluorescent dyes, and the like can be used.
The above water-soluble dyes can be used alone or in combination of two or more.
[0029]
As additives for a water-based ink for inkjet printing, a wetting agent, a pH adjusting agent, a chelating agent, an electrical conductivity adjusting agent, an ultraviolet absorber, an infrared absorber and the like are added as necessary.
Usually, the content of the additive is about 0.1 wt% to 10 wt%.
[0030]
As the wetting agent, in addition to hydroxypropyl-β-cyclodextrin, trimethylolethane, trimethylolpropane, caprolactam, urea, etc., monosaccharides such as pentose, hexose, polysaccharides such as disaccharides, trisaccharides, or derivatives thereof Certain sugar alcohols, reduced derivatives such as dechiocic acid, oxidized derivatives such as aldonic acid and uronic acid, dehydrated derivatives, solid wetting agents such as amino acids and thiosaccharides, and ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, High boiling point such as triethylene glycol, hexylene glycol, tetraethylene glycol, glycerin, 1,3-butanediol, 1,5-pentadiol, 1,2,6-hexanetriol Liquid wetting agents such as polyhydric alcohol compound having a volatility and the like.
[0031]
Examples of pH adjusters include organic amines such as diethanolamine and triethanolamine, inorganic bases such as sodium hydroxide, potassium hydroxide, and potassium hydrogen phosphate, organic acids such as tartaric acid, lactic acid, phthalic acid, acetic acid, and formic acid, sulfuric acid, Examples include mineral acids such as succinic acid.
[0032]
Preservatives include sodium O-phenylphenol, formalin, methyl p-hydroxybenzoate, Na-2-pyridinethiol-1-oxide, hexahydro-1,3,5-tris-s-triazine, tetrachloroisophthalonitrile In addition to Zn-2-pyridinethiol-1-oxide, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-octyl-4-isothiazo-3-one, 1,2-benzisothiazoline, etc. And the isothiazoline-based compounds.
[0033]
Examples of chelating agents include EDTA, acrylic acid compounds, polycarboxylic acid compounds, and phosphorus compounds.
[0034]
The water-based ink for inkjet printing of the present invention is a mixture of the water-based dye, the surfactant represented by the general formula (1), and the dialkyl ether represented by the general formula (2). It is obtained by adding pure water having a temperature of not lower than ° C. and stirring for 30 minutes, cooling to 25 ° C. (room temperature), and filtering the aqueous solution.
If low-concentration ink is required depending on the color pattern for inkjet printing, the ink prepared above may be diluted and adjusted with pure water. At that time, the surfactant represented by the general formula (1) is used. It is preferable to contain an amount in proportion to the dye concentration and an amount in which the dialkyl ether represented by the general formula (2) is inversely proportional to the surfactant concentration of the general formula (1).
The piezoelectric type head used in the ink jet printing apparatus using the ink of the present invention is already well known, and an example is shown in FIG. Ink is ejected from the nozzle B by applying electric power to deform the diaphragm E, reducing the volume of the pressure chamber C, and applying pressure.
Incidentally, cavitation in the head means that minute bubbles in the pressure chamber expand due to pressure change around the bubbles.
[0035]
When air bubbles are expanded in the pressure chamber in this way, a phenomenon that ink is not ejected from the nozzles due to so-called cavitation due to the air bubbles contracting even when a voltage is applied to the piezoelectric element and the diaphragm is deformed. Will occur.
EXAMPLES Hereinafter, although an Example is given and demonstrated about this invention, this invention is not necessarily limited to the Example.
[0036]
【Example】
Test methods for various physical properties of inks in Examples and Comparative Examples, and evaluation methods for quality such as pattern density and sharpness of the printed fabric are as follows.
[Used ink]
The compositions of the inks used in [Example 1] to [Example 4] and [Comparative Example 1] to [Comparative Example 4] are as shown in [Table 1].
[0037]
[Table 1]

[0038]
The compositions of the inks used in [Example 5] to [Example 10] and [Comparative Example 5] to [Comparative Example 10] are as shown in [Table 2].
[0039]
[Table 2]

[0040]
Each ink was mixed with the components shown in the table, stirred and mixed at 80 ° C. for 30 minutes, the liquid temperature was lowered to room temperature 25 ° C., and then filtered through a filter (Toyo Filter Paper No. 5A) to prepare an ink.
[0041]
The surfactants in Tables 1 and 2 are as shown in the following formulas (I) to (IV).
Here, R ₁ is C ₂ H ₅ , R ₂ is CH ₂ C ₆ H ₅ , and R ₃ is CH (CH ₃ ) C ₆ H ₅ .
[0042]
[Chemical formula 5]

[0043]
[Chemical 6]

[0044]
[Chemical 7]

[0045]
[Chemical 8]

[0046]
The dialkyl ethers in Tables 1 and 2 are as shown in the following formula (V).
[0047]
[Chemical 9]

[0048]
[Test and evaluation method]
(1) Method for confirming bubble generation by cavitation Ink was injected into the head of FIG. 1 described above, and ink was continuously ejected under the following printing conditions.
Immediately after this continuous ejection, one dot was ejected from each nozzle of the head under the same printing conditions onto a commercially available ink jet paper, and nozzle clogging due to the generation of bubbles due to cavitation and defective flight direction of the droplets were confirmed.
Note that the phenomenon of observing the adverse effects of cavitation includes nozzle clogging and droplet flight direction defects. Usually, the cavitation state can be determined by observing this phenomenon.
[0049]
Printing conditions;
A) Applied voltage: 150 (V)
B) Pulse width: 10 (μs)
C) Drive frequency: 5000 (Hz)
D) Printing time: 60 (min)
[0050]
Here, the evaluation was performed in the following four stages.
○: There is no problem of nozzle clogging or flight direction failure.
Δ: No nozzle clogging, but there are nozzles with poor flight direction.
×: Some nozzles are clogged.
XX: Most nozzles are clogged.
[0051]
(2) Dissolution stability After 500 g of the prepared ink was allowed to stand for one week, 100 g of this ink was filtered with suction filtration (600 Torr) [Toyo Filter Paper No. 5A (7 microns), Whatman GF-F (0.8 microns)] was determined.
[0052]
Evaluation;
Here, the evaluation was performed in the following three stages.
○: Pass smoothly (no residue)
Δ: Passes through the filter, but there is some residue ×: Impossible to pass through the filter [0053]
(3) Viscosity Viscosity was measured using the following apparatus.
Apparatus: BL type viscometer [manufactured by Tokyo Keiki Co., Ltd.]
Measurement temperature: 25 ° C
Rotor used: No. 1 type rotor rotation speed: 60rpm
[0054]
(4) Inkjet printing method and method for evaluating the quality of printed textiles a) Inkjet printing method An on-demand type serial scanning ink jet printing apparatus is used, and the printing conditions are a nozzle diameter of 100 μm and a driving voltage of 107 V. The frequency is 5 kHz, the resolution is 360 dpi, and the 4 × 4 matrix.
[0055]
Using such an ink jet printing apparatus, the following pattern was printed on a test cloth (taffeta) surface woven using nylon yarn (30d) for both warp and weft, and dried at 60 ° C. for 10 minutes.
Next, this was subjected to wet heat treatment at 102 ° C. for 20 minutes to fix the color of the dye, followed by ordinary washing treatment and drying to obtain a printed fabric.
The design was made into two patterns of (a) a square of 50 × 50 mm, (b) a cross with fine lines in the weft direction of width 0.5 mm and length 50 mm.
[0056]
b) Evaluation Method for Quality of Printed Fabric The printed fabric obtained in a) was observed and evaluated for the following items.
Surface density: The surface reflectance of the pattern (a) was measured with a color difference meter, and the surface density was indicated by the L value of the CIE 1976 Lab color system.
Bleeding: The degree of bleeding in the pattern (b) was visually evaluated as follows.
[0057]
○: No smearing △; Some smearing ×; Strong smearing [0058]
The results of the above 1) to 4) are separately listed in [Table 3].
[0059]
[Table 3]

[0060]
From [Table 3], it can be seen that the generation of bubbles due to cavitation was sufficiently suppressed by adding the specific surfactant and dialkyl ether to the ink of the present invention.
In addition, it can be seen that by adding a small amount of the surfactant and dialkyl ether of the present invention, the solubility of the ink is improved, a stable dissolved state can be maintained even when the temperature is lowered to room temperature, and the viscosity is low. .
Therefore, with the ink of the present invention, it is possible to both suppress the generation of bubbles due to cavitation and further improve the dissolution stability of the dye.
[0061]
【The invention's effect】
According to the water-based ink for ink-jet textile printing of the present invention, the generation of bubbles due to cavitation can be suppressed, so that deaeration before printing is unnecessary and the dissolution stability of the dye is improved.
Furthermore, since the viscosity is low, the ejection stability is very good.
As a result, the production efficiency of the ink jet printing apparatus is improved.
Moreover, there is no occurrence of bleeding or back-through, and a high-quality printed fabric can be obtained.
The water-based ink for inkjet printing of the present invention, when a commercially available aqueous powder dye is used as a dye, has the effect of emulsifying and stabilizing mineral oil and the like for the purpose of dust prevention contained in the commercially available dye, and is good for a long period of time. Discharge can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a piezoelectric head in an ink jet printing apparatus.
[Explanation of symbols]
A ... Ink supply path B ... Nozzle C ... Pressure chamber D ... Piezoelectric element E ... Vibration plate

Claims (6)

A water-based ink for inkjet printing comprising a water- based dye, a surfactant represented by the following general formula (1), and a dialkyl ether represented by the following general formula (2) :
When the water-based dye concentration relative to the water-based ink for inkjet printing is X wt%, the surfactant concentration is Y wt%, and the dialkyl ether concentration is Z wt%,
Y = aX
(In the formula, a represents 0.01 to 1.)
and,
Z = b / Y
(In the formula, b represents 0.1 to 0.6.)
An ink for inkjet textile printing characterized by satisfying

(Wherein R _{1 to} R ₃ represent any _one of C ₂ H ₅ , CH ₂ C ₆ H ₅ , CH ₂ CH ₂ C ₆ H ₅ , and CH (CH ₃ ) C ₆ H ₅ ; Represents H or SO ₃ M, M represents any of K, Na, NH ₄ , H, and an alkyl group having 5 or less carbon atoms, an alkylamine having an alkanol group, and an alkanolamine, and m represents 9 Represents an integer of ˜30.)

(Wherein R _{4 to} R ₅ represent any one of CH ₃ and C ₂ H ₅ , and n represents an integer of 1 to 10) When the water-based dye concentration relative to the water-based ink for inkjet printing is X wt%, the surfactant concentration is Y wt%, and the dialkyl ether concentration is Z wt%,
Y = aX
(In the formula, a represents 0.01 to 1.)
and,
Z = b / Y
(In the formula, b represents 0.1 to 0.5.)
The ink for ink-jet textile printing according to claim 1, wherein: The water-based dye for ink-jet printing according to claim 1 or 2, wherein the water-based dye is 0.01 to 20% by weight based on the water-based ink for ink-jet printing. The water-based ink for ink-jet printing according to claim 1, wherein the surfactant is 0.01 to 5% by weight with respect to the water-based ink for ink-jet printing. 5. The water-based ink for ink-jet printing according to claim 1, wherein the dialkyl ether is 0.1 to 5% by weight with respect to the water-based ink for ink-jet printing. 6. The water-based ink for ink-jet printing according to claim 1, wherein the water-based dye is an acid dye.

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