JP3798087B2 - Oil-based pigment ink - Google Patents

Description

【０００６】
本発明に用いられる溶剤は、式（１）で表される化合物である。
これは、グリセリンをベースにしたポリオキシエチレンオキシプロピレントリオールであって、更に詳しくは、エチレンオキサイドとプロピレンオキサイドのブロック共重合体とグリセリンの三官能基がエーテル結合したもの、または、エチレンオキサイドとプロピレンオキサイドのランダム共重合体とグリセリンの三官能基がエーテル結合したものである。本発明では、平均分子量が２００〜６２００のものが好ましく使用される。
特に、オキシエチレンの数平均重合度が１〜６０、かつ、オキシプロピレンの数平均重合度が１〜６０のものが好ましく用いられ、オキシエチレンの数平均重合度／オキシプロピレンの数平均重合度＝１〜２となるものが最も好ましい結果を与える。例えば、
オキシエチレンの数平均重合度：オキシプロピレンの数平均重合度＝６０：４５
オキシエチレンの数平均重合度：オキシプロピレンの数平均重合度＝３０：２５
オキシエチレンの数平均重合度：オキシプロピレンの数平均重合度＝１５：１５
などを挙げることができ、これらはいずれも良好な結果を与える。
なぜ、この割合のものが最も好ましい結果が得られるのかは定かではないが、親水性基であるオキシエチレン基と親油性基であるオキシプロピレン基がバランスよく共重合しているので、天然ゴム印や感光性樹脂印を侵さないといった水性溶剤の利点と吸湿・乾燥しないといった油性溶剤の利点を併せ持つことができたためと思われる。
これらの溶剤は、単独又は混合して使用でき、インキ全量に対して５０〜９５重量％を配合することができるが、特に好ましい範囲は、６０〜８０重量％である。
【０００７】
本発明に用いられる顔料は、特に制限されることなく従来公知の有機顔料及び無機顔料を単独又は混合して使用することができ、例えば、アゾ系、フタロシアニン系、キナクリドン系、アントラキノン系、ジオキサジン系、インジゴ・チオインジゴ系、ベリノン・ベリレン系、イソインドレノン系、アゾメチレンアゾ系などの有機顔料や、カーボンブラック、マイカ、チタン白、パール顔料、酸化鉄・アルミニウム粉・真鍮等金属顔料などの無機顔料を用いることができる。これらの顔料は通常、ポリアクリル酸、ポリメタクリル酸、スチレン−アクリル酸共重合体、及び、それらの金属塩・アンモニウム塩・アミン塩などや、他の公知の樹脂などに練り込んで加工顔料としておくと、溶剤と混合する際に容易に分散するので便利である。また、既に分散剤中に顔料を練り込んである市販の加工顔料を用いても良い。
これらの顔料は色合いを勘案しながら単独又は混合して使用でき、インキ全量に対し１〜３０重量％の顔料分が使用できる。特に好ましい範囲は３〜２５重量％である。
【０００８】
他に本発明には、顔料分散剤兼チキソトロピー性付与剤としてアクリル樹脂粉末、アクリル樹脂水溶液、から選ばれる少なくとも一種が用いられる。
本発明で用いることのできるアクリル樹脂粉末は、ポリアクリル酸、ポリメタクリル酸、スチレン−アクリル酸共重合体、スチレン−メタクリル酸共重合体等の樹脂、及び、それらのアルカリ金属塩・アンモニウム塩・アミン塩からなる樹脂の粉末であって、酸価８０以下、ガラス転移温度（Ｔｇ）が８０℃以下のものが特に好ましく用いられる。
本発明で用いることのできるアクリル樹脂水溶液は、前記アクリル樹脂粉末を水に溶解させて水溶液としたもの用いることができ、固形分２０〜６０％とするのが好ましい。
本発明に用いられるアクリル樹脂粉末を具体的に列挙すると、「ジョンクリルＪ−６８３・Ｊ−６８・Ｊ−５８６（以上、ジョンソン（株）製）、ウルトラホールド８・ルビマー１００Ｐ（以上、ＢＡＳＦジャパン（株）製）、レオジック８３０Ｌ・８３５Ｈ・２５０Ｈ・ジュリマーＡＣ−１０Ｐ（以上、日本純薬（株）製）」 等を挙げることができる。
これらのアクリル樹脂粉末、アクリル樹脂水溶液は、前記溶剤との相溶性に極めて優れており、例えば両者を混合攪拌後８０℃の状態で５日間放置した場合や３０℃の状態で５日間放置した場合においても、樹脂が析出することは全くなく、顔料を完全に分散させたままの状態を長期に渡って保つことができる。その上、チキソトロピー性も付与するため、通常の静止状態においてインキ粘度を１００００ｍＰａ・ｓ以上となし、顔料の沈降防止に寄与する。また、インキ粘度は印判等の押し付けの力によって、１０００〜２０００ｍＰａ・ｓ程度に低下するため、スタンプ台使用時はスタンプインキとして理想的な粘度となる。
上記アクリル樹脂粉末、アクリル樹脂水溶液は、少なくとも一種を用いればよく、もちろん複数種を混合して用いてもよく、インキ全量に対して２〜３０重量％が使用できる。
【０００９】
本発明では、上記物質以外にも押印後の印影の浸透乾燥を若干早めるため、浸透補助剤として、ジエチレングリコールモノブチルエーテル、トリエチレングリコールモノブチルエーテルなどのグリコールエーテルや、ポリオキシエチレングリコール等のポリアルキレングリコールを少量配合してもよい。
【００１０】
以上の添加物の他に、防腐防かび剤を使用することができるが、できれば使用しない、又は、使用しても極く少量にすることが好ましい。
【００１１】
【作用】
本発明の溶剤は、水性と油性の利点を併せもっており、吸湿・乾燥をしない、天然ゴム等の印材を侵しにくい、紙等の被捺印物に対して浸透力がある、といった性質があり、この溶剤に適した分散剤を配合することによって、スタンプインキとして有用なインキが得られる。
【００１２】
以下、実施例により本発明を更に具体的に説明するが、本発明はこの実施例によって限定されるものではない。
尚、単に「部」とあるのは「重量部」を示す。
【００１３】
（実施例１）
カーボンブラック ４部
スチレン−アクリル酸共重合体アンモニウム塩 １１部
オキシエチレンの数平均重合度６０、オキシプロピレンの数
平均重合度４５であるポリオキシエチレンオキシプロピレン
ブロック共重合体とグリセリンとのポリエーテルポリオール ７４部
ポリアクリル酸ソーダ粉末 ６部
トリエチレングリコールモノブチルエーテル ５部
上記のカーボンブラックと、スチレン−アクリル酸共重合体アンモニウム塩を三本ロールに投入し混合した後、これをプロペラ攪拌機にて残りの物質と混合して、１００ｒ．ｐ．ｍ．で５０００ｍＰａ・ｓ（２５℃）の黒色インキを得た。
【００１４】
（実施例２）
Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １６６ ５部
スチレン−アクリル酸共重合体アミン塩 １５部
オキシエチレンの数平均重合度３０、オキシプロピレンの数
平均重合度２５であるポリオキシエチレンオキシプロピレン
ブロック共重合体とグリセリンとのポリエーテルポリオール ７５部
ポリメタクリル酸ソーダ粉末 ５部
上記の顔料と、１５部のスチレン−アクリル酸共重合体アミン塩を三本ロールに投入し混合した後、これをプロペラ攪拌機にて残りの物質と混合して、１００ｒ．ｐ．ｍ．で４０００ｍＰａ・ｓ（２５℃）の赤色インキを得た。
【００１５】
（比較例１）
カーボンブラック ５部
ポリビニルピロリドン １４部
水 ２５部
グリセリン ５５部
ジアルキルスルホコハク酸ソーダ １部
上記成分からなる従来の水性インキ。
【００１６】
（比較例２）
カーボンブラック ５部
ポリビニルピロリドン ５部
ケトン樹脂 ５部
ジエチレングリコールモノブチルエーテル ２５部
エチレングリコール ６０部
上記成分からなる従来の揮発性油性インキ。
【００１７】
各実施例、及び、各比較例のインキをスタンプ台に含浸させ、市販の天然ゴム印、市販の感光性樹脂印（商品名：クリアソフト（旭化成社製ＡＲＰ樹脂印））をもって上質紙に押印した。その結果を以下に示す。
【００１８】
（表１）

【００１９】
（試験方法及び評価基準）
1.天然ゴム印の変化
…スタンプ台盤面に印面を接触させたまま、室温中で１０日間放置した後、上質紙に押印して、その印影を観察した。
○：全く変化なし。△：文字の周囲がややぼやけていた。
×：文字の周囲がぼやけており、細かい文字がつぶれた。
2.感光性樹脂印の変化
…スタンプ台盤面に印面を接触させたまま、室温中で１０日間放置した後、上質紙に押印して、その印影を観察した。
○：全く変化なし。△：文字の周囲がややぼやけていた。
×：文字の周囲がぼやけており、細かい文字がつぶれた。
3.印影の乾燥時間
…温度２０℃、湿度６５％の状態で、上質紙に押印後、上質紙を重ねて１Ｋｇ／ｃｍ²の力を加え、転写しなくなるまでの時間を計測した。
4.吸湿・乾燥性の試験
…湿度８０％・温度５０℃、湿度８０％・温度３０℃、湿度４０％・室温、の条件下でそれぞれ１ヶ月間放置した後、上質紙に押印して、その印影を観察した。
Ａ：鮮明。 Ｂ：べとつきがある。 Ｃ：かすれる。
【００２０】
【効果】
本発明は、インキが乾燥・吸湿しないのでスタンプ台の蓋を閉め忘れても盤面が乾燥して使用不能となったり、逆に空気中の水分を吸収してべとついてしまうことがなく、１年を通して使用状態が変化しない。また、天然ゴム製ゴム印や感光性樹脂印等を変質させることがなく、更に、紙等の吸収紙に対する浸透力が優れているので、押印後の印影の浸透乾燥が早い。更に、乾燥後の印影は耐水性を有し、水がかかってもにじまない。その上、本発明は油性インキでありながらアルコールのみならず水にも容易に溶解するので、捺印作業終了後の印面の洗浄が容易であり、所謂「色替え」もスムーズにできる。[0001]
[Industrial application fields]
The present invention relates to an oil-based pigment ink mainly used for a stamp stand.
[0002]
[Prior art]
Conventional stamp stands have an airtight container and a lid that can seal the surface in order to prevent ink drying. And, when used, the lid is opened and used immediately after use to prevent the ink from drying.
However, in a place where the frequency of use is high, such an action is not actually performed, and the lid and the cap are often left open. Even in normal use, it was often impossible to make a seal by drying the ink due to forgetting to return the lid.
Based on this, stamp stands using ink that does not volatilize are known, and water-based and oil-based ones are known.
Water-based materials are evaporated and dried with water alone, and therefore, a humectant such as glycerin is usually mixed to prevent drying. However, when the external environment is dry, the ink is faint, and when the external humidity is high, there is a disadvantage that the ink is excessively absorbed and sticky.
On the other hand, oil-based inks using a non-volatile organic solvent such as glycerin, castor oil, castor oil derivatives are known. Since glycerin has hygroscopicity as described above, there was a drawback that it was sticky due to excessive hygroscopicity when the external humidity was high. Castor oil does not absorb moisture or dry, but its viscosity is too high, and the drying speed of the imprint after imprinting is extremely slow, which has the disadvantage of soiling other documents and hands. Further, castor oil derivatives such as ricinoleic acid methyl ester swell rubber stamps made of natural rubber, and photosensitivity as disclosed in JP-A-50-41606, JP-A-50-155322, and the like. There was a disadvantage that the resinous resin mark would swell.
[0003]
[Problems to be solved by the invention]
Accordingly, the present inventor has found a novel oil-based pigment ink that does not absorb and dries the ink itself and does not alter the natural rubber rubber mark or the photosensitive resin mark, thereby completing the present invention.
[0004]
[Means for Solving the Problems]
Polyoxyethylene oxypropylene triol in which triblock functional groups of ethylene oxide and propylene oxide and glycerin are ether-bonded, or polyfunctional copolymer of random copolymers of ethylene oxide and propylene oxide and trifunctional groups of glycerin in ether linkage A pigment ink comprising oxyethyleneoxypropylene triol, a pigment, and at least one selected from an acrylic resin powder and an aqueous acrylic resin solution .
[0005]
(Chemical formula 1)

[0006]
The solvent used in the present invention is a compound represented by the formula (1).
This is a polyoxyethyleneoxypropylene triol based on glycerin, more specifically, a block copolymer of ethylene oxide and propylene oxide and a trifunctional group of glycerin ether-bonded, or ethylene oxide and propylene A random copolymer of oxide and a trifunctional group of glycerin are ether-bonded. In the present invention, those having an average molecular weight of 200 to 6200 are preferably used.
In particular, those having a number average degree of polymerization of oxyethylene of 1 to 60 and a number average degree of polymerization of oxypropylene of 1 to 60 are preferably used, and the number average degree of polymerization of oxyethylene / number average degree of polymerization of oxypropylene = Those that are 1-2 give the most favorable results. For example,
Number average degree of polymerization of oxyethylene: Number average degree of polymerization of oxypropylene = 60: 45
Number average degree of polymerization of oxyethylene: Number average degree of polymerization of oxypropylene = 30: 25
Number average degree of polymerization of oxyethylene: Number average degree of polymerization of oxypropylene = 15: 15
And all of these give good results.
It is not clear why this ratio gives the most favorable results, but the hydrophilic oxyethylene group and the lipophilic oxypropylene group are copolymerized in a well-balanced manner. This seems to be due to the combined advantages of an aqueous solvent that does not attack the photosensitive resin mark and an oily solvent that does not absorb moisture or dry.
These solvents can be used alone or in combination, and can be blended in an amount of 50 to 95% by weight based on the total amount of the ink, but a particularly preferred range is 60 to 80% by weight.
[0007]
The pigment used in the present invention is not particularly limited, and any conventionally known organic pigment and inorganic pigment can be used alone or in combination. For example, azo, phthalocyanine, quinacridone, anthraquinone, dioxazine Organic pigments such as Indigo / Thioindigo, Berinone / Berylene, Isoindolenone, Azomethyleneazo, and inorganic pigments such as carbon black, mica, titanium white, pearl pigments, metal pigments such as iron oxide, aluminum powder, and brass Can be used. These pigments are usually kneaded into polyacrylic acid, polymethacrylic acid, styrene-acrylic acid copolymers, and their metal salts, ammonium salts, amine salts, and other known resins as processed pigments. It is convenient because it is easily dispersed when mixed with a solvent. Moreover, you may use the commercially available processed pigment which has already kneaded the pigment in the dispersing agent.
These pigments can be used singly or in combination while taking the hue into consideration, and a pigment content of 1 to 30% by weight based on the total amount of ink can be used. A particularly preferred range is 3 to 25% by weight.
[0008]
In addition, in the present invention, at least one selected from an acrylic resin powder and an aqueous acrylic resin solution is used as a pigment dispersant / thixotropic agent.
The acrylic resin powder that can be used in the present invention is a resin such as polyacrylic acid, polymethacrylic acid, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and alkali metal salts / ammonium salts thereof. A resin powder comprising an amine salt having an acid value of 80 or less and a glass transition temperature (Tg) of 80 ° C. or less is particularly preferably used.
The acrylic resin aqueous solution that can be used in the present invention can be an aqueous solution obtained by dissolving the acrylic resin powder in water, and preferably has a solid content of 20 to 60%.
The acrylic resin powder used in the present invention is specifically listed as follows: “John Crill J-683 / J-68 / J-586 (above, manufactured by Johnson Co., Ltd.), Ultra Hold 8 / Rubimer 100P (above, BASF Japan) And Rheozic 830L / 835H / 250H / Durimer AC-10P (Nippon Pure Chemicals Co., Ltd.) ”and the like.
These acrylic resin powders and acrylic resin aqueous solutions are extremely excellent in compatibility with the solvent. For example, when both are mixed and stirred and left at 80 ° C. for 5 days or at 30 ° C. for 5 days However, the resin does not precipitate at all, and the state in which the pigment is completely dispersed can be maintained for a long time. In addition, since thixotropy is also imparted, the ink viscosity is 10,000 mPa · s or more in a normal stationary state, contributing to prevention of pigment settling. Further, since the ink viscosity is reduced to about 1000 to 2000 mPa · s by the pressing force of a stamp or the like, it becomes an ideal viscosity as a stamp ink when using a stamp stand.
At least one kind of the acrylic resin powder and the acrylic resin aqueous solution may be used. Of course, a plurality of kinds may be mixed and used, and 2 to 30% by weight can be used with respect to the total amount of the ink.
[0009]
In the present invention, in addition to the above substances, in order to slightly accelerate the penetrating and drying of the imprint after stamping, as a penetration aid, glycol ethers such as diethylene glycol monobutyl ether and triethylene glycol monobutyl ether, and polyalkylene glycols such as polyoxyethylene glycol May be blended in small amounts.
[0010]
In addition to the above additives, antiseptic and antifungal agents can be used, but it is preferable not to use them if possible, or to use a very small amount even if used.
[0011]
[Action]
The solvent of the present invention has the advantages of being water-based and oil-based, and does not absorb moisture or dry, has a property of not easily invading printing materials such as natural rubber, and has a penetrating power to printed objects such as paper, By blending a dispersant suitable for this solvent, an ink useful as a stamp ink can be obtained.
[0012]
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples.
Note that “part” simply means “part by weight”.
[0013]
Example 1
Carbon black 4 parts Styrene-acrylic acid copolymer ammonium salt 11 parts Polyoxypolyethyleneoxypropylene block copolymer having a number average degree of polymerization 60 of oxyethylene and a number average degree of polymerization 45 of oxypropylene and a polyether polyol of glycerin 74 parts sodium polyacrylate powder 6 parts triethylene glycol monobutyl ether 5 parts The above carbon black and styrene-acrylic acid copolymer ammonium salt were put into a three roll and mixed, and then this was mixed with a propeller stirrer. Mixed with the substance, 100 r. p. m. A black ink of 5000 mPa · s (25 ° C.) was obtained.
[0014]
(Example 2)
C. I. Pigment Red 166 5 parts Styrene-acrylic acid copolymer amine salt 15 parts Polyoxyethylene oxypropylene block copolymer having a number average degree of polymerization of 30 oxyethylene and a number average degree of polymerization of oxypropylene of 25 and a polyether of glycerin Polyol 75 parts Polymethacrylic acid soda powder 5 parts The above pigment and 15 parts styrene-acrylic acid copolymer amine salt are put into a three-roll roll and mixed, and then this is mixed with the remaining substance with a propeller stirrer. 100r. p. m. A red ink of 4000 mPa · s (25 ° C.) was obtained.
[0015]
(Comparative Example 1)
Carbon black 5 parts Polyvinylpyrrolidone 14 parts Water 25 parts Glycerin 55 parts Dialkyl sulfosuccinate 1 part Conventional water-based ink comprising the above components.
[0016]
(Comparative Example 2)
Carbon black 5 parts Polyvinylpyrrolidone 5 parts Ketone resin 5 parts Diethylene glycol monobutyl ether 25 parts Ethylene glycol 60 parts Conventional volatile oil-based ink comprising the above components.
[0017]
The ink of each example and each comparative example was impregnated into a stamp stand, and imprinted on high-quality paper with a commercially available natural rubber stamp and a commercially available photosensitive resin stamp (trade name: Clearsoft (ARP resin stamp manufactured by Asahi Kasei Co., Ltd.)). . The results are shown below.
[0018]
(Table 1)

[0019]
(Test method and evaluation criteria)
1. Change of natural rubber stamp: After leaving the stamp surface in contact with the stamp base surface for 10 days at room temperature, it was imprinted on high quality paper and the imprint was observed.
○: No change at all. Δ: The characters were slightly blurred.
X: The surroundings of the characters were blurred and the fine characters were crushed.
2. Change in photosensitive resin mark: The specimen was left at room temperature for 10 days with the stamp surface in contact with the stamp base, and then imprinted on high-quality paper, and the imprint was observed.
○: No change at all. Δ: The characters were slightly blurred.
X: The surroundings of the characters were blurred and the fine characters were crushed.
3. Imprint drying time: In a state where the temperature was 20 ° C. and the humidity was 65%, after imprinting on the high quality paper, the high quality paper was superimposed, a force of 1 kg / cm ² was applied, and the time until transfer was stopped was measured.
4. Hygroscopicity / Drying Test: After leaving for 1 month under conditions of humidity 80%, temperature 50 ° C, humidity 80%, temperature 30 ° C, humidity 40%, room temperature, and then imprinting on fine paper, The imprint was observed.
A: Clear. B: There is stickiness. C: It fades.
[0020]
【effect】
In the present invention, since the ink does not dry and absorb moisture, the board surface does not dry and becomes unusable even if the lid of the stamp stand is forgotten to be closed, and conversely, it absorbs moisture in the air and does not stick. The state of use does not change throughout the year. In addition, the rubber stamp made of natural rubber, the photosensitive resin stamp or the like is not altered, and the penetrating power to the absorbent paper such as paper is excellent. Furthermore, the imprint after drying has water resistance and does not bleed even if it is splashed with water. In addition, since the present invention is an oil-based ink, it easily dissolves in water as well as alcohol, so that it is easy to clean the stamped surface after the stamping operation and so-called “color change” can be performed smoothly.

Claims (1)

Polyoxyethylene oxypropylene triol in which triblock functional groups of ethylene oxide and propylene oxide and glycerin are ether-bonded, or polyfunctional copolymer of random copolymers of ethylene oxide and propylene oxide and trifunctional groups of glycerin in ether linkage An oil-based pigment ink comprising at least one selected from oxyethyleneoxypropylene triol, a pigment, an acrylic resin powder, and an aqueous acrylic resin solution .