JP3615075B2 - Writing / recording pigment ink, writing instrument and recording device - Google Patents

Description

（注）
筆記性
○：繊維束芯で可
△：繊維束芯で不可、スポンジ芯で可
インキジェット印刷性
○：実施例１の溶剤希釈率で良好に印刷できる。
△：実施例１の溶剤希釈率では良好に印刷できず、希釈率を高くすることで印刷できるが、濃度が不足する。
【００３２】
実施例４
α−メチルスチレン２０部、イソボルニルメタクリレート１２０部、ヒドロキシプロピルメタクリレート２００部、２−エチルヘキシルアクリレート６０部、アゾビスイソブチロニトリル１２部、エタノール２４０部、エチルシクロヘキサン１２０部、エトキシプロパノール２４０部を重合容器に仕込み、冷却管をセットして撹拌しながら８０℃で２時間重合し、アゾビスイソブチロニトリル４部を追加し、更に８０℃で８時間撹拌し、重合を完結させた。樹脂分４０％、粘度が２９０ｍＰａの樹脂液２が得られた。樹脂の数平均分子量は９，２００であった。
【００３３】
上記の樹脂液２の３００部とカーボンブラック＃１０００（三菱化学社製）６０部とジエタノールアミン０．６部、エタノール２６０部、エチルシクロヘキサン１１４部及びエトキシプロパノール２６０部とを横型メディア分散機を使用して分散させて顔料インキを得た。粘度は５．２ｍＰａであった。又、該インキを５０℃で一週間保存し、粘度を計ったところ５．３ｍＰａであり、粘度変化は少なかった。
上記のインキを繊維束の芯を有するペン体に詰めてポリエチレンフィルムに筆記したところ、良好に筆記できた。
【００３４】
比較例３
イソボルニルメタクリレートをスチレンに代える以外は実施例４と同様にして粘度が５．８ｍＰａの顔料インキを得た。このインキを５０℃で１週間保存した後粘度を測定したところ９．３ｍＰａであった。粘度上昇が大きく、筆記用具インキとして使用できなかった。
【００３５】
【発明の効果】
以上の本発明によれば、顔料インキは粘度が低く、粘度は経時的に安定しており、特に低粘度のインキを必要とする筆記具用及びインキジェット印刷機用のインキに適している。
本発明の顔料インキを筆記具に充填した筆記用具は、プラスチックフィルムや、ガラス、皮革製品、金属表面や塗装した表面、紙等に筆記でき、更に発泡スチロールや軟質塩化ビニールにも筆記でき、耐光性にも優れ、筆記具を使用している人や同じ部屋、又は環境にいる人の健康や大気汚染等の環境に対する悪影響が少ない物である。
又、本発明の顔料インキは、インキジェット印刷においてはポリエステルフィルム等に印刷しても発色が良く、耐久性の良い印刷物が得られる。[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a writing / recording pigment ink, a writing instrument, and a recording device, and more particularly, to a writing / recording pigment ink using an alcohol solvent, a writing instrument incorporating the ink, and a recording device using the ink. .
[0002]
[Prior art]
Conventionally, a marking ink used for a writing instrument using a fiber bundle core or a felt core is made of a resin, a pigment, and a solvent, and a dye is used as the pigment. As the solvent, an ester solvent or an aromatic solvent is used from the viewpoint of solubility in a resin and solubility in a dye.
[0003]
However, it is desirable not to use aromatic solvents because they adversely affect the health of workers (organic solvent poisoning) and are air pollutants. Although ink for writing is becoming water-based, solvent-based marking pens are still widely used. This is because solvent-based inks have excellent writing properties for plastic films such as polyethylene and drying properties immediately after writing on plastic films.
[0004]
Inkjet printing is digital printing controlled by a computer, and printing information and images are directly supplied from a computer through a cable, and plate making is not necessary. Therefore, it is particularly suitable for printing on a display with a small number of copies, and recent advances in ink jet printers have enabled high definition and large printing. Ink for inkjet printing must have low viscosity and excellent stability, but there are inks that use dyes in solvent systems, but inks for inkjet printing that use pigments are technically difficult Therefore, water-based ink is used in the pigment type.
However, water-based inks have very little resin as a color developing agent, and thus good color development is not obtained. There is also a problem of adhesion to a plastic film.
Under such circumstances, development of alcohol-based inks for ink jet printing with good color development using pigments is strongly desired.
[0005]
By the way, as seen in paints and the like in the prior art, a large amount of resin dispersion is expected to disperse the pigment in the resin solution. For example, styrene, butyl methacrylate, 2-ethylhexyl acrylate, etc. are included as the parent pigment component. In the case where a resin is synthesized by addition polymerization and the pigment is dispersed using this resin, and the dispersion power of the resin can only provide an insufficient pigment dispersion, a dispersant or a pigment treatment agent has been conventionally used. With ordinary paints, sufficient dispersion was obtained with conventional dispersants or pigment treatment agents.
However, the pigment ink for writing / recording has an extremely low required viscosity as compared with the paint, and the degree of pigment dispersion is extremely high. In response to such demands, the use of conventional resins, dispersants, or pigment treatment agents does not provide sufficient dispersion of the pigment, or the dispersion of the pigment dispersion liquid due to the desorption of the dispersant or the lack of affinity between the pigment and the resin. It was extremely difficult to obtain the required pigment dispersion because the viscosity changed with time.
[0006]
[Problems to be solved by the invention]
In solvent-based writing inks, if a solvent that has a high tolerance for ethyl alcohol and other organic solvent poisoning can be used as a solvent for writing inks, it will be beneficial to the health of the person using the writing instrument, the person in the same room, or the same environment. In addition, the problem of air pollution can be improved by not using an aromatic solvent, and the problems of drying and wetting on plastic films, which are disadvantages of water-based inks, are also eliminated. Moreover, alcohol is a renewable resource from nature and the use of such solvents is preferred.
[0007]
However, with a conventionally known alcohol-soluble resin, it is extremely difficult to obtain a pigment dispersion having low viscosity, high dispersion, and high stability necessary for a writing pigment ink even if a dispersant is used.
Therefore, an object of the present invention is to use a sufficient amount of an alcohol-soluble resin with respect to the pigment, have a low viscosity and good pigment dispersibility, a person using a writing instrument, the same room or the same environment. It is intended to provide a writing / recording ink and a writing instrument using a pigment as a colorant, and a jet printing ink having good coloring and adhesion, which have little influence on the health of people in the country.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have found that the object can be achieved by using a resin containing a specific addition-polymerizable monomer unit that is soluble in an alcohol solvent. The present invention has been completed.
That is, the present invention relates to a pigment ink for writing / recording comprising an organic pigment (A), a resin (B), and a solvent (C), wherein (meth) acrylic acid isoform having 1 to 80% by weight of the resin (B). Writing / recording characterized in that it is a resin containing bornyl ester units, and the solvent (C) is a solvent having at least 10% by weight of one alcoholic hydroxyl group in the molecule and a boiling point of 150 ° C. or lower. Pigment ink, and writing instruments and recording equipment using the ink.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to preferred embodiments.
The writing / recording pigment ink of the present invention uses an organic pigment as a colorant, and uses a solvent containing a solvent having one alcoholic hydroxyl group in the molecule and a boiling point of 150 ° C. or lower as the solvent. It is comprised from the resin containing (meth) acrylic-acid isobornyl ester soluble in water.
[0010]
The solvent used in the present invention is an alcohol solvent containing at least 10% by weight, preferably 50 to 100% by weight of the above solvent. Examples of the solvent include ethyl alcohol, propyl alcohol, methoxypropanol, ethoxypropanol, propyloxyethanol and the like, and these are used alone or in admixture of two or more. Solvents other than these solvents can be used in combination as long as they do not contradict the spirit of the present invention. For example, ethyl acetate, propyl acetate, cyclohexane, methylcyclohexane, ethylcyclohexane, methylethylketone, methylpropylketone, and the like can be used in combination.
[0011]
The resin used in the present invention is required to be soluble in the above alcohol solvent, and such a resin includes an addition polymerizable monomer having a carboxyl group, a hydroxyl group or an amide group, and an addition copolymer with these. It is obtained by copolymerizing a polymerizable monomer. Below, the monomer used for manufacture of the resin of this invention is demonstrated.
[0012]
Examples of the addition polymerizable monomer having a carboxyl group include acrylic acid and methacrylic acid (in the present invention, these are referred to as (meth) acrylic acid); fumaric acid, maleic acid, itaconic acid, and alkyls thereof. Monoesters, hydroxyalkyl monoesters, etc .; monoesters of hydroxyalkyl acrylates such as hydroxyethyl acrylate and hydroxypropyl acrylate and dibasic acids such as succinic anhydride, phthalic anhydride, cyclohexanedicarboxylic anhydride, etc. Can be mentioned.
[0013]
As the addition polymerizable monomer having a hydroxyl group, (meth) acrylic acid hydroxyalkyl ester, for example, (meth) acrylic acid hydroxyethyl or hydroxypropyl; the above (meth) acrylic acid hydroxyalkyl ester and dibasic acid mono Examples of the ester and dihydroxyalkyl ester include oxalic acid, phthalic acid, or cyclohexanedicarboxylic acid and monoethyl ester of hydroxyethyl (meth) acrylate or hydroxypropyl and ethylene glycol or propylene glycol.
In addition, carbon number of the alkyl group in said monomer is about 1-12.
[0014]
Examples of the addition polymerizable monomer having an amide group include (meth) acrylamide, N-substituted (meth) acrylamide, for example, (meth) acrylic acid butoxymethylamide, N-ter-butylacrylamide, N-ter- Butylmethacrylamide, diacetone acrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N-methylol (meth) acrylamide, N-alkyloxyethyl (meth) acrylamide and the like can be used.
[0015]
In order to make it possible to produce a pigment dispersion that is soluble in an alcohol solvent, has good water resistance and alkali resistance, and has low viscosity and good viscosity stability over time, a resin monomer As a component, it is necessary to use (meth) acrylic acid isobornyl ester in a range soluble in an alcohol solvent.
[0016]
By using a resin obtained by copolymerizing the above monomers, a low-viscosity pigment dispersion can be obtained. In order to further impart water resistance, flexibility, and other physical properties to the resin, as necessary. Further, a hydrophobic addition polymerizable monomer copolymerizable with the above monomer can be copolymerized within a range soluble in an alcohol solvent. Examples of such monomers include alkyl esters of (meth) acrylic acid, such as (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid butyl ester. , (Meth) acrylic acid octyl ester, (meth) acrylic acid lauryl ester, (meth) acrylic acid stearyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid benzyl ester, (meth) acrylic acid tetrafurfuryl, etc .; styrene Styrene derivatives, such as α-methylstyrene; dialkyl esters of dibasic acids, such as dialkyl esters of maleic acid, dialkyl esters of fumaric acid, dialkyl esters of itaconic acid, etc .; and vinyl acetate, (meth) acrylonitrile, etc. Available
[0017]
The resin of the present invention can be obtained by copolymerizing the above monomers. The proportion of (meth) acrylic acid isobornyl ester used is 1 in the monomer mixture (the same applies to other monomers). -80% by weight, preferably 10-60% by weight. The proportion of other monomers used is appropriately determined so as to satisfy the performance required for the resin as long as the resin obtained is soluble in the alcohol solvent, and is not particularly limited. For example, the use ratio of the carboxyl group, hydroxyl group or amide group-containing monomer is 10 to 70% by weight, preferably 20 to 60% by weight, and can be copolymerized with the above monomers. The proportion of the monomer used is 0 to 50% by weight, preferably 0 to 20% by weight.
[0018]
The method for producing the above-mentioned resin used in the present invention is not particularly limited, but conventionally known radical polymerization initiators such as organic peroxides, azo compounds and persulfates can be used, for example, suspension polymerization and the above-described methods. It can be produced by solution polymerization using an alcohol solvent or the like as a polymerization solvent.
The number average molecular weight (measured by GPC, in terms of standard polystyrene) of the resin used in the present invention is 2,000 to 100,000, preferably 2,000 to 50,000. The acid value of the resin is preferably 300 (mg KOH / g) or less, more preferably 0 to 180.
[0019]
Any conventionally known organic pigments can be used as the pigment used in the present invention. For example, azo, condensed azo, anthraquinone, perylene / perinone, indigo / thioindigo, isoindolinone, azomethine, azomethine azo, quinacridone, aniline black, phthalocyanine blue, dioxazine violet, etc. it can.
[0020]
The writing / recording ink of the present invention can be produced in the same manner as a conventional writing / recording ink production method using an organic pigment, the above-described resin and solvent, and the production method itself is not particularly limited.
The disperser that can be used in the present invention is not particularly limited, and for example, a kneader, an attritor, a ball mill, a sand mill using glass or zircon, a horizontal media disperser, a colloid mill, or the like can be used.
At that time, an organic pigment is dispersed in a solid resin (hereinafter referred to as a pigment chip), the pigment chip is dissolved in an alcohol solvent, and if necessary, a resin is further added to obtain a pigment ink. You can also.
[0021]
As a method for obtaining a pigment chip, for example, (1) a solid resin obtained by suspension polymerization or a solid resin separated from a solution of a resin obtained by solution polymerization and a treated pigment, kneader, Banbury mixer, mixing roll Or a method of kneading with a three-roll or the like alone or in combination, dispersing the pigment under heating and then crushing or cutting to obtain a chip, (2) water-soluble solvent solution of resin Then, the processed cake press cake is mixed with a kneader, heated to the softening temperature of the resin or higher to remove the water, and if necessary, further dispersed using a three roll or an extruder, and pulverized. In addition, there are a method of obtaining a pigment chip by cutting, and a method (3) of flushing a treated pigment press cake and a solid resin at a temperature higher than the softening temperature of the resin.
[0022]
In the writing / recording pigment ink of the present invention, the organic pigment is used in an amount of usually 5 to 500 parts by weight per 100 parts by weight of the resin.
The concentration of the organic pigment in the pigment ink of the present invention is usually 0.3 to 50% by weight, preferably 0.5 to 30% by weight, although it depends on the type of pigment. Further, the viscosity of the ink is usually 1 to 50 millipascals (mPa), preferably 2 to 30 mPa, but may be required to be lower than 7 mPa depending on the structure of the writing instrument. What is particularly important is that the viscosity stability over time is excellent. However, the pigment ink of the present invention exhibits excellent viscosity stability over time by using the above-mentioned resin together with an organic pigment. .
[0023]
In addition to the pigment, resin, and solvent, various additives can be added to the ink of the present invention as necessary. Examples of such additives include durability improvers such as pigment dispersants, ultraviolet absorbers and antioxidants; anti-settling materials; release agents or release improvers; fragrances, antibacterial agents; plasticizers and anti-drying agents. Etc. can be used, and if necessary, a dye can be added. Further, as the resin, resins compatible with the resin other than the resin used in the present invention can be used in combination as long as the dispersion stability of the organic pigment is not lowered.
[0024]
The pigment ink obtained above can usually be used as it is, but by removing coarse particles that may be slightly present in a centrifuge, ultracentrifuge or filter, This is preferable because the reliability of the writing / recording tool can be improved.
[0025]
The writing instrument of the present invention is obtained by filling the container having a porous core with the writing / recording pigment ink of the present invention thus obtained. The container is not particularly limited as long as it has a size and shape that allows easy writing, as with various writing tools having a conventionally known porous core. The material of the container including the lid may be metal, plastic, or composite material as long as it does not substantially permeate the solvent.
The porous core is not particularly limited in structure and material as long as the ink can move from the container to the tip of the core according to writing, but writing properties, durability, and solvent resistance are required.
For example, as fiber bundles and felt cores, synthetic fibers such as polyester, polypropylene, nylon, polyacrylonitrile, vinylon, cellulose and cellulose-based regenerated fibers, and natural fibers such as wool, silk, and cotton can be used. As the open cell foam, a hard and soft urethane resin foam, a foam of acetalized polyvinyl alcohol, and a foam of recycled fiber can be used. As the ink occlusion body, an open-cell foam of plastic such as a bundle of fibers, a felt-like article, a knitted article, or the like can be used.
[0026]
【Example】
Next, the present invention will be described more specifically with reference to examples and comparative examples. In the text, “%” or “%” is based on weight unless otherwise specified.
[0027]
Example 1
16 parts α-methylstyrene, 124 parts isobornyl methacrylate, 140 parts hydroxypropyl methacrylate, 60 parts methacryloyloxyethyl succinate, 60 parts lauryl methacrylate, 16 parts azobisisobutyronitrile, 240 parts ethanol, 120 parts ethylcyclohexane Then, 240 parts of ethoxypropanol is charged into a polymerization vessel, a condenser tube is set, polymerization is performed at 75 ° C. for 2 hours, and polymerization is further performed at 80 ° C. for 6 hours.
After cooling, the resin solution was removed from the flask. This is designated as resin liquid 1. The resin content was 40%, the viscosity was 260 mPa, and the number average molecular weight of the resin (measured by GPC, converted to standard polystyrene) was 8,800.
[0028]
350 parts of the above resin liquid 1, 50 parts of red insoluble azo pigment (PR258), 2,4-bis [anthraquinonyl (-1 ′)-amino] -6-bis [(N, N-dimethylamino) ) Propyl] imino-s-triazine (dispersant) 5 parts, ethanol 240 parts, methylcyclohexane 115 parts and ethoxypropanol 240 parts are dispersed using a horizontal media disperser, and coarse particles are removed by ultracentrifugation. Thus, a pigment ink was obtained. The average particle size was 95 nm and the viscosity was 4.2 mPa. Further, the ink was stored at 50 ° C. for one week, and the viscosity was measured and found to be 4.2 mPa. There was no change in viscosity.
[0029]
Next, when the ink described above was packed in a pen body having a fiber bundle core and written on a polyethylene film, writing was successful. When an ink obtained by adding 20 parts of ethoxypropanol to 100 parts of the ink was used for printing with an ink jet printer, a good printed matter was obtained.
[0030]
Examples 2-3 and Comparative Examples 1-2
A pigment ink was obtained in the same manner as in Example 1 except that a resin synthesized using the monomers listed in Table 1 was used, and evaluated in the same manner as in Example 1. The results are shown in Table 1 together with the results of Example 1.
[0031]
Table 1

(note)
Writability ○: Acceptable with fiber bundle core △: Not acceptable with fiber bundle core, Acceptable with sponge core
Ink jet printability : Good printing can be performed with the solvent dilution rate of Example 1.
(Triangle | delta): It cannot print favorably with the solvent dilution rate of Example 1, and it can print by making a dilution rate high, but a density | concentration is insufficient.
[0032]
Example 4
20 parts α-methylstyrene, 120 parts isobornyl methacrylate, 200 parts hydroxypropyl methacrylate, 60 parts 2-ethylhexyl acrylate, 12 parts azobisisobutyronitrile, 240 parts ethanol, 120 parts ethylcyclohexane, 240 parts ethoxypropanol The polymerization vessel was charged and polymerized at 80 ° C. for 2 hours with stirring by setting a cooling tube, and 4 parts of azobisisobutyronitrile was further added and stirred at 80 ° C. for 8 hours to complete the polymerization. Resin liquid 2 having a resin content of 40% and a viscosity of 290 mPa was obtained. The number average molecular weight of the resin was 9,200.
[0033]
Using a horizontal media disperser, 300 parts of the above resin liquid 2, 60 parts of carbon black # 1000 (Mitsubishi Chemical Corporation), 0.6 parts of diethanolamine, 260 parts of ethanol, 114 parts of ethylcyclohexane and 260 parts of ethoxypropanol were used. To obtain a pigment ink. The viscosity was 5.2 mPa. Further, the ink was stored at 50 ° C. for one week, and the viscosity was measured to be 5.3 mPa and the viscosity change was small.
When the above ink was packed in a pen body having a fiber bundle core and written on a polyethylene film, it was successfully written.
[0034]
Comparative Example 3
A pigment ink having a viscosity of 5.8 mPa was obtained in the same manner as in Example 4 except that isobornyl methacrylate was replaced with styrene. This ink was stored at 50 ° C. for 1 week, and the viscosity was measured and found to be 9.3 mPa. The viscosity increase was large and could not be used as a writing instrument ink.
[0035]
【The invention's effect】
According to the present invention described above, the pigment ink has a low viscosity and the viscosity is stable over time, and is particularly suitable for ink for writing instruments and ink jet printers that require low viscosity ink.
Writing instruments filled with the pigment ink of the present invention can be written on plastic films, glass, leather products, metal surfaces, painted surfaces, paper, etc., and also on polystyrene foam and soft vinyl chloride, making it light resistant. It is also an object that has little adverse effects on the environment such as the health and air pollution of people who are using writing instruments, the same room, or people in the environment.
In addition, the pigment ink of the present invention is good in color even when printed on a polyester film or the like in ink jet printing, and a printed matter with good durability can be obtained.

Claims (8)

In a writing / recording pigment ink composition comprising an organic pigment (A), a resin (B), and a solvent (C), the (meth) acrylic acid isobornyl ester unit is 1 to 80% by weight of the resin (B). A pigment ink for writing and recording, wherein at least 10% by weight of the solvent (C) is a solvent having one alcoholic hydroxyl group in the molecule and having a boiling point of 150 ° C. or lower. The pigment ink for writing and recording according to claim 1, wherein the pigment content is 0.5 to 30% by weight. The pigment ink for writing and recording according to claim 1, wherein the acid value of the resin (B) is 300 or less. The writing / recording pigment ink according to claim 1, wherein the solvent having an alcoholic hydroxyl group is at least one selected from ethyl alcohol, propyl alcohol, methoxypropanol, ethoxypropanol, and propyloxyethanol. The pigment ink for writing and recording according to claim 1, wherein the number average molecular weight of the resin (B) is 2,000 to 50,000. 2. The writing / recording pigment ink according to claim 1, which is a marking pen ink or an on-demand ink jet recording ink. A writing instrument comprising a writing / recording pigment ink according to claim 1, wherein the writing instrument has a porous core. A recording apparatus using an ink jet printer, wherein the recording / printing pigment ink according to claim 1 is used.