WO2001036548A1

WO2001036548A1 - Electrocoagulation printing ink and its use

Info

Publication number: WO2001036548A1
Application number: PCT/JP1999/006430
Authority: WO
Inventors: Masami Nizuma; Hideaki Kumada; Hiroyuki Kawashima
Original assignee: Toyo Ink Mfg. Co., Ltd.
Priority date: 1998-05-18
Filing date: 1999-11-18
Publication date: 2001-05-25
Also published as: EP1153993A1; EP1153993A4; AU1182500A

Abstract

An improved electrocoagulation printing ink comprising acetylene glycol-based surfactant, an electrocoagulable polymer, a coloring agent, a soluble electrolyte and a liquid medium. The printing ink is capable of being removed with ease from the surface of a positive cylindrical electrode in continuous printing and free from the occurrence of a unfavorable spot-like stain in the part having no images of a printed matter. A printed matter which is free from the lowering of quality by a spot-like stain in an unprinted part thereof, and an electrocoagulation printing method for providing such a printed matter are also disclosed.

Description

Description Electro-coagulation printing ink and its utilization Technical field

The present invention relates to improvements in the field of electrocoagulation printing. In particular, the present invention relates to an improved electrocoagulation printing ink which does not cause undesired spot-like stains on a non-image portion of a printing medium when performing continuous printing. Background art

Electrocoagulation printing is a printing method that does not require a plate at all, and can obtain prints directly from digital image signals from a computer. Therefore, unlike conventional printing methods such as offset printing, letterpress printing, screen printing, and gravure printing, there is no need for steps such as plate making and plate changing, so that printing time can be reduced. In addition, since this printing can use water-based ink, it is superior to the printing method that uses oil-based ink in terms of air pollution, fire hazard, and safety and health during work.

? For the gas coagulation printing method and apparatus, see US Patent Nos. 4,895, 629 (Registration date: January 23, 1990), 5, 538, 601 ( Registration date: July 23, 1996), No. 5, 693, 206 (registration date: February 2, 1997).

In this electrocoagulation printing method, after the anode surface is cleaned, an oily substance is applied to the anode surface, and an image is formed by electrocoagulation of a printing ink (electrocoagulation printing ink) containing a volatilizable electrolyte on the surface. A dot of coagulated ink corresponding to the ink is formed, the uncoagulated printing ink remaining on the anode surface, that is, the non-coagulated ink is removed, and the exposed coagulated ink dot is transferred to the printing medium, and Therefore, an image is printed on the printing medium.

Therefore, the electrocoagulation printing device is fixed as a rotating anode in the form of a cylinder with a passive surface, a means for cleaning the surface of the anode, a means for applying an oily substance, a means for supplying printing ink, and a fixed anode. , A plurality of cathodes spaced apart from each other by a distance, a means for removing non-coagulated ink, and a means for transferring solidified ink dots on the anode to a printing medium.

After the electrocoagulation of the printing ink, the non-coagulated ink is removed from the cylinder surface, for example, by rubbing one surface of the anode cylinder with a soft rubber squeegee. If the printing time is prolonged due to continuous printing, it becomes difficult to completely remove the non-coagulated ink from the anode surface with a soft rubber squeegee. Background stains) In particular, spot-like background stains occur in the non-image area, and there is a problem that the quality of the obtained printed matter is reduced. In order to completely remove the non-solidified ink from the anode surface in response to this problem, if the hardness of the squeegee and the pressure to press the squeegee against the anode cylinder surface are increased, the solidified ink dots themselves are removed or damaged. There was a problem that the quality of the obtained printed matter deteriorated. It was a complicated task to remove non-coagulated ink to the extent that spot-like background stains did not occur and to adjust the squeegee so that the dots of the coagulated ink were not damaged. Disclosure of the invention

It is an object of the present invention to solve the above-mentioned disadvantages which cannot be solved by existing electrocoagulation printing inks based on the prior art. That is, when performing continuous printing, an improved electrocoagulation printing ink that can be easily removed from the surface of the positive electrode cylinder and does not cause undesired spot-like background stains on the non-image area of the printing medium, It is an object of the present invention to provide a printed material that does not cause quality deterioration due to the background soiling and an electrocoagulation printing method that can produce the printed material.

The present inventors have conducted intensive studies in view of the above-mentioned situation, and as a result, the electrocoagulation printing ink containing an acetylene glycol-based surfactant can easily remove the non-coagulation ink from the anode cylinder surface. The present inventors have found that the quality of printed matter is not degraded due to spot-like background stains, and have reached the present invention.

That is, the present invention relates to an electrocoagulable printing ink containing an acetylene glycol-based surfactant, an electrocoagulable polymer, a colorant, a soluble electrolyte, and a liquid medium. The present invention also relates to a printed matter printed with the above-described electrocoagulated printing ink. Furthermore, the present invention relates to an electrocoagulation printing method using the above electrocoagulation printing ink. The expression "electrocoagulation printing method" as used herein means that an image is formed by electrocoagulation of a printing ink containing a polymer that can be electrolytically coagulated, and the image formed in this way is transferred to a printing substrate. Means the entire printing process. The whole printing process includes the following steps (a) to (f):

(a) cleaning the anode surface; (b) coating the anode surface with microdroplets of an oily substance; (c) filling the gap between the negative and positive electrodes with printing ink; (d) selection corresponding to the desired image Voltage is applied to the formed cathode to form dots of coagulated ink on the surface of the anode coated with microdroplets of oily substance. (E) Non-coagulated printing ink, t [J or non-coagulated ink A desired image is formed on the printing medium by removing from the anode surface, and (f) transferring dots of the solidified ink formed on the anode surface to the printing medium.

The expression "electrocoagulation of printing ink" as used herein applies only to step (d) of the above process and applies a voltage to the cathode to destroy the passivation film on the anode surface from the anode surface. The polyvalent metal ions are eluted, and the printing ink is solidified by the chemical bond between the polyvalent metal ions and the polymer which can be electrolytically coagulated contained in the printing ink, and a dot of the coagulated ink is formed on the positive electrode. Means that. The polyvalent metal ion eluted from the surface of the anode is, for example, trivalent iron or trivalent aluminum ion when a positive electrode made of stainless steel or aluminum is used in a gas coagulation printing method. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing an example of an electrocoagulation printing apparatus using the electrocoagulation printing ink of the present invention.

% \) \ \ Best mode for implementing

The present invention will be described in detail. In the following description, "ink" means "electrocoagulation printing ink". The acetylene glycol-based surfactant used in the ink of the present invention is a compound having at least one carbon-carbon triple bond and two hydroxyl groups, and is used alone or as a mixture of two or more. be able to. The acetylene glycol-based surfactant is preferably a nonionic acetylene glycol-based surfactant represented by the chemical formula (1), and particularly preferably, R, and R ₂ in the chemical formula (1) are CH-CI. -2,4,7,9-tetramethyl-5-decyne-4,7-diol wherein I is (CH _{: i} ) and m + n is 0.

CH ₃ CH ₃

R, — CH ₂ -C— C≡C— C— CH ₂ -R ₂ (i)

OR ₃ OR4

In the formula,, R2 is CH: There CH2 or _{CH: i} - CH _(CH: der Ri, _R: is (CH, CH20) is m-H, R ₄ is (CH2 CH2 O) n-H Der Where m + n is an integer from 0 to 50.

The nonionic acetylene glycol-based surfactant represented by the chemical formula (1) can be obtained from manufacturers such as Jur Products Japan and Kawaken Fine Chemical.

The content of the acetylene glycol-based surfactant is preferably 0.01 to 2% by weight based on the total weight of the ink. If the content is less than 0.01% by weight, the effect of preventing the occurrence of spot-like background stains is small, and it tends to be difficult to obtain excellent quality printed matter. On the other hand, when the content is more than 2% by weight, the occurrence of spot-like background stains can be prevented, but the reflection density of the non-image area of the printing medium tends to be slightly higher, and the dot of the coagulated ink is reduced. There is a problem that the transfer to the printing medium becomes difficult and the density of the printed image decreases.

The method of blending the acetylene glycol-based surfactant into the ink may be a conventionally known method. For example, it can be mixed at the time of ink production, or mixed with ink immediately before printing. The polymer capable of electrolytic coagulation used in the ink of the present invention is a polymer capable of chemically bonding to a polyvalent metal ion, and has a functional group such as an amide group, an amino group, and a carboxyl group.

有する is preferred. The weight-average molecular weight of the electrocoagulable polymer is preferably in the range of about 100,000 to about 1,000,000, more preferably 100,000 to 600,000. , 0000. The weight-average molecule j of the polymer that can be electrolytically coagulated can be determined by gel filtration chromatography (detector: light scattering meter) or the relational expression between the limiting viscosity of the polymer and the as average molecular weight. If the weight average molecular weight of the polymer that can be electrolytically coagulated is less than about 100, 000, the ink becomes difficult to coagulate and the density of the printed matter decreases. On the other hand, when the weight average molecular weight of the electrolytically coagulable polymer exceeds about 1,000, 0000, the viscosity of the ink increases, and the workability during ink production and printing tends to be poor. The skeletal structure of the polymer that can be electrolytically coagulated may be branched having a branch, but is preferably linear.

Examples of electrocoagulable bolimers include natural polymers such as albumin, gelatin, casein, and agar, as well as polyacrylic acid, modified polyacrylic acid, polyacrylamide, modified polyacrylamide, and polyacrylic acid hydrazide. Synthetic polymers can be mentioned. The electrolytically coagulable polymer can be used alone or

2% or more can be mixed and used. The electrocoagulable polymer is preferably present in an amount of about 4 to about 15% by weight, and more preferably in an amount of about 6 to about 12% by weight, based on the total path of the ink. It is. If the content of the polymer capable of electrolytic coagulation is less than about 4% by weight, the concentration of the coagulated ink transferred to the substrate tends to decrease. When the content of the electrocoagulable polymer is more than about 15% by weight, the viscosity of the ink is high, and the workability at the time of manufacturing and printing of the ink tends to be poor.

Preferred electrolytically coagulable polymers are modified polyacrylamides, including nonionic, anionic, and cationic acrylamide polymers. Modified polyacrylamide can be obtained from manufacturers such as Arakawa Chemical Industries, Mitsubishi Chemical, Inc., Lima Chemicals, Mitsui Toatsu Chemicals, Mitsui Cytec, and Sanyo Chemical. A particularly preferred polymer capable of electrolytic coagulation is a linear anionic acrylamide polymer, and specific examples include Accost Length 86 (ACC @ STRENGTH 86) available from Mitsui Cytec. Examples of the colorant used in the ink of the present invention include pigments and dyes used in general printing inks, paints, and recording agents.

As the pigment, an organic pigment or an inorganic pigment can be used.

Examples of azo pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethineazo, diketopyrrolopyrrole, and diketopyrrolopyrrole. Sondolin-based pigments are exemplified.

It is preferable to use azo pigments for ink and red ink. For example, permanent yellow (Permanen 1 Yellow) DGR or DHG, permanent rubin (available from IIOE CHST) Permanent R ubine) F6B or L6B. Copper-phthalocyanine-based pigments are suitable for indigo ink, and include, for example, Heliogen Blue (Heliogen Blue) D7072DD available from BASF.

Examples of the inorganic pigment include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, and chromium oxide. It is preferable to use carbon black as the black ink. In particular, when carbon black having an oil absorption of 65 to 120 m1 / 100 g and an average particle diameter of 35 to 100 nm is used, a printed matter having a bluish color and a high degree of blackness and density can be obtained. As a specific example of carbon black, for example, carbon black Monak 1 2 having an oil absorption of 72 m 1/100 g and an average particle diameter of 75 nm available from CABOT CORP. 0 (Carbon B lack Monarch (registered trademark) 120).

The pigments can be used alone or in combination of two or more for the purpose of adjusting the hue and concentration. The pigment may be used in the form of an aqueous slurry, or a slurry obtained by pulverizing the slurry by drying such as spray drying may be used. The pigment is contained in the ink in an amount that ensures the concentration of the dot of the coagulated ink formed by the electrocoagulation of the printing ink and the coloring power, preferably about 4 to about 20% by weight based on the total weight of the ink. included. As the dye, an acid dye, a basic dye, a direct dye, a reactive dye, a disperse dye, a gold-containing dye and the like can be used.

Pigments and dyes can be used in combination for the purpose of adjusting hue and density. However, the use of dyes may deteriorate the dispersion stability of the pigment and reduce the water and light resistance of the printed image, so the content is 40% by weight or less of the pigment, and 25% by weight or less of the pigment. Is preferable.

When the colorant used in the ink of the present invention is a pigment, a dispersant can be used to stably disperse the pigment in a liquid medium. It is also possible to stably disperse the pigment in a liquid medium using the polymer capable of electrolytic solidification. At this time, the decoagulable polymer alone can be dispersed, and a dispersing agent can be used in combination to stably disperse the pigment.

Surfactants such as anionic, nonionic, cationic and amphoteric surfactants can be used as the dispersant.

The dispersant is preferably included in the ink in an amount of about 0.05 to about 5% by weight, more preferably about 0.1 to about 2% by weight, based on the total weight of the ink. If the dispersant i is less than 0.05% by weight, the storage stability of the ink is poor, and if it is more than 5% by weight, the concentration of the solidified dot transferred to the printing material tends to decrease. .

A preferred dispersant is an alkali metal salt of a naphthalene sulfonic acid formaldehyde condensate, more preferably a compound represented by the chemical formula (2). Among them, those in which M is sodium and the n force is 5 to 12 are preferable.

Alkali metal salts of naphthalenesulfonic acid formaldehyde condensate are available from Kao, Sanyo Kasei, Sannobuco, Daiichi Kogyo, Kyoeisha, Toho Chemical, and Baume 'Filatex Canada, Inc. c.) and can be obtained from manufacturers. The compound in which M is sodium and n is 7 in chemical formula (2) is sold as an aqueous solution under the trademark of Clospersc 2500 by Baume 'Filatex' Canada and its active ingredient Is about 42% and the average molecular weight is about 2000.

Here, in the formula, M is an alkali metal, and n is an integer of 2 to 15.

The soluble electrolyte used in the ink of the present invention is used to increase the conductivity of the ink and to cause the desired breakdown of the passive film on the anode surface. Preferred soluble electrolytes are halides, especially chlorides. For example, halides of 7 alkali metals and halides of alkaline earth metals include lithium chloride, sodium chloride, potassium chloride, and calcium chloride, and ammonium chloride, nickel chloride, copper chloride, and manganese chloride. Can be used. The soluble electrolyte can be used alone or in combination of two or more.

The conductivity of the ink is preferably 1 to 20 OmS / cm (25 ° C), and if the conductivity of the ink is less than 1 mS / cm, it is transferred to the printing substrate. The anti-concentration of the solidified ink is low. Therefore, the amount of the soluble electrolyte is blended in such an amount that the conductivity of the ink becomes ^ iitl as described above, and is generally about 5 to about 10% by weight, more preferably about 10% by weight based on the total weight of the ink. It is included in the ink in an amount of about 6 to about 9% by weight. As a liquid medium for dissolving or dispersing an acetylene glycol-based surfactant, a colorant, an electrolytically coagulable polymer, and a W-soluble electrolyte to provide a desired ink, water is desirably used.

The wood ink may further include a sequestering agent that forms a complex with the polyvalent metal ion. The polyvalent metal ion is an essential component for forming a dot of the coagulated ink in the electrocoagulation printing. However, if the multivalent metal ion is present in the ink before step (d), the printing ink is converted into an electric charge in step (d). Before solidification, the electrocoagulable polymer in the ink and the polyvalent metal ions are chemically bonded, increasing the viscosity of the ink. I The viscosity of the ink increases with the concentration of the polyvalent metal ion, and when the polyvalent metal ion concentration is high, the ink gels.

Polyvalent metal ions may be contained in the raw materials used in the ink or may be mixed in during the ink manufacturing process. In addition, as the non-solidified ink removal T-stage used in step (e), the non-solidified ink is removed from the anode surface, for example, by rubbing the anode surface with a soft rubber squeegee, and returned to the printing ink supply means. In the case of microfluidization, a small amount of coagulated ink is recovered together with the non-coagulated ink, so the recycled ink contains a small amount of polyvalent metal ions eluted from the anode surface. As the electrocoagulation printing time increases, the concentration of polyvalent metal ions in the ink supplied from the printing ink supply means may increase.

When the concentration of polyvalent metal ions in the ink, for example, ferric ion exceeds about 25 ppm, the viscosity of the ink becomes too high to be suitable for normal printing, and at about 140 ppm, ink gelation occurs. . In order to prevent such an undesirable increase in the viscosity of the ink, a metal ion sequestering agent can be added to the ink.

If the content of the sequestering agent is small relative to the concentration of a polyvalent metal ion such as ferric ion in the ink, the concentration of the ion exceeds 25 ppm, and W- increases the viscosity of the ink. jl Thus, the sequestering agent complexes the polyisocyanate ion such as ferric ion in the ink so that the concentration of the ion is less than about 20 ppm, preferably less than about 15 ppm. Used in an amount to maintain the proper state.

Also, when a large amount of a sequestering agent is added to the concentration of a polyvalent metal ion such as ferric ion in the ink, the ion is almost completely complexed, but is complexed in the ink. A large amount of sequestrant that can be formed remains. The gold ion sequestering agent remaining in the ink forms a complex with the polyvalent metal ion, which is an essential component for forming solidified ink dots that elute from the anode surface due to the destruction of the passive film in step (d). It has a negative effect on the formation of a chemical bond between the polyvalent metal ion and the polymer which can be electrolytically solidified contained in the ink. If the effect is extremely large, the concentration of the solidified ink dot transferred to the printing medium may decrease, and the solidified ink dot itself may not be formed. For this reason, sequestering agents adversely affect the chemical bond between polyvalent metal ions, which occur during the electrocoagulation of printing ink, and the polymer that can be electrocoagulated. It is used in an amount that does not affect the taste.

Therefore, the content of the sequestering agent is determined by complexing a polyvalent metal ion such as ferric ion to obtain a concentration of the ion in the ink before step (d) of about 20 ppm or less, preferably More than about 15 ppm or less, which is sufficient to make a chemical bond between the polyvalent metal ion eluted from the anode surface and the polymer that can be coagulated during electrocoagulation of the printing ink. It is preferred to use less than the amount. The content depends on the type of sequestering agent used, in addition to the concentration of polyvalent metal ions in the ink, and further depends on the type and amount of the electrolytically coagulable polymer contained in the ink. Also change.

The sequestering agent used is preferably a compound capable of forming a cyclic structure incorporating a metal ion as a central metal atom. Such ring formation increases the stability of the binding of the sequestering agent. As such a sequestering agent, polyaminocarboxylic acid and salts thereof are preferable. Polyamino acids Rubonic acid includes ethylenediaminetetraacetic acid (EDTA), iminodiacetic acid (IDA), hydroxyethyliminodiacetic acid (HI DA), ethylenebis (hydroxyphenyl) glycine (EHPG), and hydroxyethylethylenediamine Acetic acid

(HEDTA), tri-triacetic acid (NTA), ethylene-bis (oxyethylene di-tri-tetra) tetrasuccinic acid (EGTA), cyclohexanediaminetetraacetic acid (CyDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetramine hexaacetic acid (T TIIA). The sequestering agents can be used alone or in combination of two or more. Particularly preferred sequestering agents are EDTA and its salts, which are inexpensive and readily available.

Preferably, the sequestering agent is included in the ink at about 0.01 to about 0.3% by weight of the total weight of the ink, more preferably about 0.01 to about 0.2 IES. It is included in the amount of%.

The method for incorporating the gold bending ion sequestering agent into the ink may be a conventionally known method. For example, it can be mixed at the time of manufacture of the ink, or mixed immediately before or during the printing operation. In the electrocoagulation printing method, as described above, when printing is performed for a long time, the amount of polyvalent metal ions in the ink may gradually increase. III It is preferable that the ink at the beginning and the ink added during the printing be an ink in which m of the sequestering agent to be mixed is changed.

Hereinafter, the ink used at the start of printing is called “starting ink”, and the ink added during printing is called “replenishing ink”. When the ink is used as a starting ink, the sequestering agent is preferably present in an amount of 0 to about 0.2 IBia%, more preferably about 0.01 to about 0, based on the total weight of the ink. It is contained in the ink at 15% by weight. On the other hand, in the case of a replenishing ink, the sequestering agent incorporated in the ink is preferably about 0% based on the total weight of the ink in consideration of complexing polyvalent metal ions that increase during printing. 0.05 to about 0.3% by weight, more preferably from about 0.1 to about 0.3% by weight in the ink.

The ink of the present invention preferably further contains an antiseptic / antifungal agent to prevent the occurrence of fungi, mold and the like. Preferred preservatives / fungicides include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, zinc pyridinthione-1-oxide, 1,2-benzisothiazoline-3-one, 1-benzisothiazoline Amine salts of -3-one. For example, the preservative and fungicide sold by GRAY PRODUCTS under the trademark PARMETOL K-50 can be used. The antiseptic / fungicide is included in the ink in an amount of preferably about 0.01 to about 2% by weight ffl, more preferably about 0.01 to about 1% by weight, based on the total weight of the ink. . The antiseptic and fungicide can be used alone or as a mixture of two or more, depending on the type of fungi, mold and the like.

In addition, the ink of the present invention may be used, if necessary, with an infrared absorber, an ultraviolet absorber, a fragrance, an antioxidant, an antifoaming agent, a silane coupling agent, a plasticizer, a flame retardant, a humectant, an organic solvent, and the like. Can also be included.

The ink of the present invention dissolves and / or dissolves these additives such as acetylene glycol-based surfactant, polymer capable of electrolytic coagulation, coloring agent, soluble electrolyte, and if necessary, sequestering agent in a liquid medium. It is manufactured by dispersing.

When a pigment is used as a coloring agent, a pigment dispersion is prepared by dispersing the pigment in a liquid medium with a dispersant and / or an electrolytically coagulable polymer in advance. Ink can be manufactured by mixing the pigment dispersion with a soluble electrolyte, an acetylene glycol-based surfactant, and, if necessary, a deflocculating polymer, a liquid medium, a sequestering agent, and a preservative. preferable. The particle size distribution of the pigment in the pigment dispersion can be adjusted by appropriately adjusting the size of the grinding media of the disperser, the filling ratio of the grinding media, the time of the dispersion process, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, and the like. Can be adjusted. As the dispersing machine, generally used, for example, a roller mill, a ball mill, a pebble mill, an attritor, a sand mill and the like can be used.

When coarse particles or bubbles are contained in the ink, it is preferable to remove the ink by filtration or defoaming in order to prevent electrocoagulation of the printing ink and reduce the quality of an image. Conventionally known filters and defoamers can be used.

The hydrogen ion concentration (P H) of the ink produced by the above method is preferably in the range of about 3 to about 8 when measured at 25 ° C. More preferably, ΔI is from about 3 to about 6. If the pH is out of this range, the concentration of the solidified ink transferred to the printing medium tends to decrease. In order to adjust the pH of the ink, a conventionally known acid such as hydrochloric acid, sulfuric acid, acetic acid, sodium hydroxide, potassium hydroxide, or ammonium hydroxide can be used for i'J !.

The viscosity of the produced ink is preferably in the range of about 100 to about 150 OmPas (cps) (30 ° C). If the viscosity of the ink is lower than 100 OmPas, the concentration of the solidified ink transferred to the printing medium will be low, and if it is higher than 150 mPa-s, the ink will be used during manufacturing and printing. It tends to be inferior. The viscosity of the ink can be adjusted by appropriately selecting the type and amount of the raw material to be supplied, for example, a volatilizer, a colorant, and a liquid medium capable of electrolytic coagulation. When a pigment is used as a coloring agent, the viscosity of the ink can be adjusted by adjusting the particle size and particle size distribution of the pigment in the ink.

Kimei's ink has a pH of about 3 to about 6 and about 0.01 to about 2% by weight, based on the total weight of the ink, of the nonionic acetylene glycol-based compound of formula (1). About 4 to about 15% by weight of anionic acrylamide polymer, about 4 to about 20% by weight pigment, about 5 to about 10% by weight alkali metal halide, 60 to about 80% by weight of water, about 0.01 to about 0.3% by weight of polyaminocarboxylic acid or salts thereof, and about 0.01 to about 2% by weight of preservative and fungicide It is preferably an aqueous liquid dispersion.

Next, a method of using the ink of the present invention will be described.

FIG. 1 shows an outline of an electrocoagulation printing apparatus 1 for performing printing using the ink of the present invention. In the electrocoagulation printing apparatus 1, a base plate 5 is arranged on a plurality of standing feet 3, and a plurality of frames 7 are erected vertically on the base plate 5. I have. Further, a pair of vertical plates 9 are provided on the upper portion of the frame 7, and each of the vertical plates 9 holds a cylindrical anode 11 rotatable by a drive motor (not shown). This anode 11 is stretched in a direction perpendicular to the paper surface in FIG. 1 and has an anode active surface having a passivation film.

Further, the electrocoagulation printing apparatus 1 includes an oily substance applying means 13 for dispersing an oily substance on the anode active surface along the anode 11 and forming microdroplets of the oily substance on the anode active surface. A printing ink supply means 15 having a temperature control means (not shown) for supplying the ink of the invention to the anode; and a plurality of dots of coagulation ink representing a desired image by electrocoagulation of the printing ink. A printing head 19 having a cathode 17 formed thereon is provided, and a non-coagulating ink removing means 21 such as a squeegee for removing non-coagulating ink from the anode active surface is provided. Then, the plurality of solidified ink dots representing the desired image on the obtained monopolar active surface are brought into contact with the printing material W, and the dots of the coloring ink are transferred from the anode active surface to the printing material. Accordingly, an impression cylinder 23 is provided as a means for printing the image on the printing medium.

In addition, below the anode 11, a temperature control means (not shown) for removing coagulated ink, non-coagulated ink, oily substance, etc. from the anode active surface by washing the solidified ink remaining on the anode active surface is provided. Anode surface cleaning means 25 is provided.

With such a configuration, after the oily substance droplets of the oily substance are applied to the anode active surface of the rotating anode 11 by the step 13, the ink is supplied to the fixed distance by the printing ink supply means 15. The ink of the present invention is supplied between the cathode 17 and the anode 11. The supplied ink is solidified by applying a voltage between the positive and negative electrodes. A dot of ink is formed, and the non-coagulated ink is removed from the anode active surface by a squeegee 21.

Next, the dots of the solidified ink formed on the anode active surface are transferred to the print medium W by contacting the print medium W with the dots of the solidified ink between the anode 11 and the impression cylinder 23. Printed.

Multicolor printing can be performed by preparing a desired number of electrocoagulation printing apparatuses 1 shown in FIG. 1 and sequentially printing the ink of the present invention having a desired hue in each electrocoagulation printing apparatus! Becomes For example, by arranging four electrocoagulation printing apparatuses 1 shown in Fig. 1 in tandem, and printing the yellow, indigo, red, and black inks of the present invention in succession with & Become.

Further, as an electrocoagulation printing apparatus that performs printing using the ink of the present invention, a sensor of the type described in the aforementioned Amerili Patent No. 5, 538, 601 (registered on July 23, 1996). An evening drum type printing device may be used. This printing method consists of a printing stage consisting of an I-pole surface cleaning means, an oily substance applying means, a printing ink supply means, a plurality of cathodes located at a fixed distance from the anode, a non-solidified ink removing means, and a transfer means. Is arranged around a single rotating cylindrical anode having a passive surface. For example, process printing can be performed by arranging four printing stages around a single anode and printing the yellow, indigo, red, and black inks of the present invention successively in each printing stage.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples at all without departing from the technical spirit of the present invention.

In the examples, ρ II is a glass electrode type hydrogen ion concentration meter manufactured by Electrochemical Instruments, conductivity is IIOR IΒ CONDUCT IVITY METER DS-12, and viscosity is Tokimec B-type viscometer. Each was measured using. The anti-density of the printed matter was measured using X-Rite (registered trademark) MOD EL 408 manufactured by X-Rite.

(¾Example 1)

Ink used as a starting ink was manufactured from the following raw materials. — “C arb on B lack Mon archl 20”

Pigment sold under the trademark 8.8% by weight

— Sold under the trademark “CL〇S PERSE 2500”

0.75% by weight of an anionic dispersant aqueous solution

-Sold under the trademark "AC C〇S TRENGTH 86"

Anionic acrylamide polymer 8 8% by weight potassium monochloride (soluble electrolyte) 8

I Sodium EDTA dihydrate (sequestering agent)

0.03% by weight

-Sold under the trademark "Surfinol 104 PA"

Acetylene glycol surfactant solution 0.1% by weight-sold under the trademark "PARMETOL K-50"

Preservatives and fungicides 0 1% by weight Water (liquid medium) 72 62% by weight

100% by weight of D S

^ First, a pigment was dispersed in water with a dispersant using a sand mill to obtain a pigment dispersion. Next, a polymer was added to the obtained pigment dispersion, and potassium chloride and an antiseptic / antifungal agent were sequentially added. Subsequently, a metal ion sequestering agent, “Safinol 104 PA” (2,4,7,9-tetramethyl-5-decyne-4,7-diol in isopropyl alcohol, available from Air Products Japan, Inc. After mixing the active ingredient (about 50% by weight), the mixture was filtered and defoamed. The ink thus obtained has a pH of about 4.1 (25 ° C), a conductivity of about 112 mS / cm (at 25) and a viscosity of about 500 mPa · s (30 ° C). there were.

The ink was used in an electrocoagulation printing apparatus as shown in FIG. 1 of the type described in US Pat. No. 5,693,206. The printing device includes a positive electrode made of stainless steel, a device for washing the anode with high-pressure water containing detergent, a device for forming micro droplets of an oily substance on the surface of the anode, a printing ink supply device, and a certain distance from the anode. Multiple cathodes with a diameter of about 50 μm are placed, non-solidified ink is soft polyurethane It consists of a device that removes from the anode surface with a stainless steel squeegee and a polyurethane impression cylinder. The ink, the cleaning liquid used in the device for cleaning the anode, and the anode cylinder were heated to 40 ° C.

The reflection density of the solidified ink transferred to the printing medium was 1.3, and no spot-like soiling occurred on the continuous printing bub for about 1 hour. The reflection density of the non-image portion of the printed matter was as low as 0.01, and the printed matter was good without any deterioration in quality due to spot-like background stains.

(Example 2)

An indigo ink used as a starting ink was produced from the following raw materials in the same manner as in the ink of Example 1.

I Under the trademark "Heliog eBlue D 7072DD"

Copper-phthalocyanine indigo pigment sold 10.5% by weight I Sold under the trademark "CLOS PERSE 2500"

4.2% by weight of an anionic dispersant solution Sold under the trademark “ACCOSTRENGTH 86”

Anionic acrylamide polymer 7% by weight Potassium monochloride (soluble electrolyte) 8.4% by weight DTPA (sequestering agent) 0.0 3% by weight One is sold under the trademark "Surfinol 104 PA"

Acetylene glycol-based surfactant solution 0.1% by weight – sold under the trademark “PARMETOL K-50”

Antiseptic, fungicide 0.1% by weight Water (liquid medium) 69.67% by weight Total 100% by weight The pH of the ink thus obtained is about 4.1 (25 ° C), conductivity Was about 105 mS / m 2 (25 ° C.) and the viscosity was about 520 mPa · s (30 ° C.).

The ink was used in the same electrocoagulation printing apparatus as in Example 1, and the quality of the obtained printed matter was evaluated in the same manner as in Example 1. Of solidified ink transferred to the substrate The reflection density was 1.3, and no spot-like soiling occurred during continuous printing for about 1 hour. The reflection density of the non-image area of the printed matter was as low as 0.01, and the printed matter was good without any deterioration in quality due to spot-like background stains.

(^ Example 3)

'In the raw materials of the ink described in Example 2 above, the pigment was 10.5% by weight of an azo red pigment sold under the trademark "Permanent Ru bin F 6B", and the gold sealing agent was used. A red ink used as a starting ink was manufactured using the same raw materials and method as in Example 2 except that EDTA was 0.03% by weight. The pH of the ink so obtained was about 4.1 (at 25), the conductivity was about 104 mS / cm (25 ° C), and the viscosity was about 52 OmPa · s (30 ° C).

The ink was used in the same electrocoagulation printing apparatus as in Example 1, and ¹ of the obtained printed matter was evaluated in the same manner as in Example 1. The anti-concentration of the solidified ink transferred to the printing medium was 1.3, and no spot-like soiling occurred during continuous printing for about one hour. The reflection density of the non-image area of the printed matter was as low as 0.01, and the printed matter was good without any deterioration in quality due to spot-like background stains.

(^ Example 4)

^ In the raw materials of the ink described in Example 1, the acetylenic alcohol-based surfactant / ¾ is represented by R i and R in the chemical formula (1) as CH _{: i} -CH (CH: and m + n is 2 A black ink used as a starting ink was produced using the same raw materials and method as in Example 1 except that the compound was 0.05% by weight and water was 72.67% by weight. The pH of the ink was about 4.1 (25 ° C), the conductivity was about 112 mS / cm (25 ° C), and the viscosity was about 51 OmPa · s (30 ° C).

Ink was used in the same electrocoagulation printing apparatus as in Example 1, and the quality of the obtained printed matter was evaluated in the same manner as in Example 1. The reflection density of the coagulated ink transferred to the printing medium was 1.3, and no spot-like background stains occurred during continuous printing for about 1 hour. The reflection density of the non-image area of the printed matter was as low as 0.01, and it was a good printed matter without quality deterioration due to spot-like background stains. (¾Example 5)

¾ 中 In the raw materials of the ink described in Example 1, except that the acetylenic alcohol-based surfactant “Surfinol 104 PA” was 0.01% by weight and water was 72.7% by weight, A black ink used as a starting ink was produced using the same raw materials and method as in Example 1. The pH of the ink thus obtained was about 4.1 (25 ° C), the conductivity was about 112 mS / cm (at 25), and the viscosity was about 49 OmPa · s (30 ° C) .

The ink was used in the same electrocoagulation printing apparatus as in Example 1, and the quality of the obtained printed matter was evaluated in the same manner as in Example 1. The reflection density of the coagulated ink transferred to the printing medium was 1.3, but undesired spot-like background stains occurred slightly in the non-image area of the printed matter about 10 minutes after the start of printing. However, the reflection density of the spots was as low as 0.02, and the prints had almost no quality deterioration due to spot-like background stains.

(Example 6)

The same procedures as in Example 1 were carried out except that the acetylene glycol-based surfactant “Sa-finol 104 PA” was 5% by weight and the water was 67.72% by weight among the raw materials for the ink described in Example 1. A black ink used as a starting ink was manufactured using the same raw materials and method. Is the pH of the ink thus obtained about 4.1 (25 ° C)? The rate was about 112 mS / cm (25 ° C) and the viscosity was about 53 OmPa · s (30).

The ink was used in the same electrocoagulation printing apparatus as in Example 1, and the quality of the obtained printed matter was evaluated in the same manner as in Example 1. The reflection density of the coagulated ink transferred to the printing medium was slightly lower at 1.2, and the reflection density of the non-image area of the printed material was 0.02, slightly higher than the other examples, but about one hour. No spotted background stains were generated during continuous printing of No. 1, and there was no quality deterioration due to the spotted background stains.

(¾Example 7) The same raw materials and methods as in Example 1 except that the sequestering agent and the antiseptic / fungicidal agent were not used in the raw materials of the ink described in Example 1, and water was 72.75% by weight. Produced black ink used as a starting ink. The pH of the ink thus obtained was about 4.1 (25 ° C), the electrical conductivity was about 112 mS / cm (25 ° C), and the viscosity was about 50 OmPa-s (30).

The ink was used in the same electrocoagulation printing apparatus as in Example 1, and the quality of the obtained printed matter was evaluated in the same manner as in Example 1. The reflection density of the coagulated ink transferred to the printing medium was 1.3, and no spot-like background stains occurred during continuous printing for about 1 hour. The reflection density of the non-image portion of the printed matter was as low as 0.01, and the printed matter was good without a decrease in the product due to spot-like background stains. The viscosity of the ink increased slightly compared to Example 1 when the printing time exceeded about 30 minutes.

(Comparative Example 1)

Starting with the same raw materials and method as in Example 1, except that the acetylene recall-based surfactant ij ij was not used and water was used at 72.72% by weight among the raw materials for the ink described in Example 1. A black ink used as a working ink was manufactured. The pH of the ink thus prepared is about 4.1 (25 ° C), the conductivity is about 112mS / cm (25 ° C), and the viscosity is about 490] 11? 3.3 (30 ° C) Met.

The ink was used in the same electrocoagulation printing apparatus as in Example 1, and the quality of the obtained printed matter was evaluated in the same manner as in Example 1. The reflection density of the coagulated ink transferred to the print medium was 1.3, but undesired spot-like background stains occurred in the non-image area of the printed matter about 10 minutes after the start of printing. The reflection density of the spots was 0.06, and the quality of the printed matter was poor.

(Comparative example 2)

The starting materials were the same as in Example 2 except that the acetylene glycol-based surfactant was not used and the water content was 69.77% by weight. Ink was used as an ink. The pH of the ink thus obtained is about 4.1 (25 ° C) and the conductivity is about 105 mS / cm (25 ° C) and the viscosity was about 49 OmPa · s (30 ° C).

The ink was used in the same electrocoagulation printing apparatus as in Example 1, and the quality of the obtained printed matter was evaluated in the same manner as in Example 1. The reflection density of the coagulated ink transferred to the print medium was 1.3, but undesired spot-like background stains occurred in the non-image area of the printed matter about 10 minutes after the start of printing. The reflection density of the spots was as high as 0.06, and the quality of the printed matter was poor.

(Comparative example 3)

The starting materials used in Example 3 were the same as in Example 3, except that the acetylene glycol surfactant was not used and the water content was 69.77% by weight. A red ink used as an ink was manufactured. The pH of the ink thus obtained was about 4.1 (25), the conductivity was about 104 mS / cm (25 ° C), and the viscosity was about 49 OmPa · s (30).

The ink was used in the same electrocoagulation printing apparatus as in Example 1, and the quality of the obtained printed matter was evaluated in the same manner as in Example 1. The reflection density of the coagulated ink transferred to the printing medium was 1.3, but undesired spot-like background stains occurred in the non-image area of the printed matter about 10 minutes after the start of printing. The reflection density of the spot portion was 0.06, and the quality of the printed matter was poor.

上の Business availability

As described above, the electrocoagulated printing ink according to the present invention is suitable for use as an ink that can easily remove non-coagulated ink from the surface of the anode cylinder. Further, the electrocoagulated printing ink of the present invention is suitable for use as an ink for obtaining a printed matter of extremely good quality without spot-like background stains even when the printing time is long.

Claims

The scope of the claims

1. An electrocoagulated printing ink containing an acetylene glycol-based surfactant, an electrocoagulable polymer, a colorant, a soluble electrolyte, and a liquid medium.

2. The electrocoagulated printing ink according to claim 1, further comprising a sequestering agent.

3. The electrocoagulated printing ink according to claim 1, wherein the acetylene glycol-based surfactant is a nonionic acetylene glycol-based surfactant represented by the chemical formula (1).

CH ₃ CH ₃

Rj— CH ₂ -C— C≡C— C— CH ₂ -R ₂ ri)

OR ₃ OR ₄

and ffl, wherein,, R2 is CH ₃ - CH or CH - CH (CH: Der is, is (CH.CH ^ O) mH, R 4 is Ri (CH2 CH2 O) n-H Der, m + n is an integer from 0 to 50.

4. The electrocoagulable printing ink according to claim 3, wherein the acetylene glycol-based surfactant is 2,4,7,9-tetramethyl-5-decyne-4,7-diol.

5. The electrocoagulated printing ink according to any one of claims 1, 2 or 4, comprising 0.01 to 2% by weight, based on the total weight of the ink, of an acetylene glycol-based surfactant.

6. The electrocoagulated printing ink according to claim 3, comprising 0.01 to 2% by weight, based on the total weight of the ink, of an acetylene glycol-based surfactant.

7. Printed matter printed by the electrocoagulation printing ink according to claim 1,.

8. An electrocoagulation printing method using the electrocoagulation printing ink according to claim 1.