JP5499370B2 - Oxidative polymerization type offset ink composition - Google Patents

Description

  The present invention relates to an offset ink composition used for printing books, books, leaflets, catalogs, and the like, and more specifically, the flowability and temporal stability of ink and the drying property during printing and on the printing press. The present invention relates to an oxidation polymerization type offset ink composition having excellent stability and low environmental load.

  Oxidation polymerization offset printing is a printing method in which vegetable oil is oxidized and solidified by oxygen in the air and dried after printing on paper. If the vegetable oil used in the ink is small, the stability of the ink on the printing press is inferior and the viscosity of the ink is increased and the fluidity is lowered. In addition, the printed matter after ink drying is inferior in friction resistance and gloss. If the vegetable oil used in the ink is large, the penetrability into the paper is inferior, causing rubbing on the printing machine, blocking after binding on the printing paper surface, etc., resulting in poor quality as a printed matter. Moreover, the temporal stability of the ink in a storage container is inferior.

  In recent years, the offset ink industry has also been challenged to reduce carbon dioxide emissions and control environmental pollution as a countermeasure against global warming, and there has been a demand for carbon neutralization by shifting from fossil resources to biological resources.

  In the past, various oxidative polymerization type offset inks have been studied from the viewpoint of environmental friendliness, and most of them are the transfer of solvent components to biological resources (Patent Documents 1 and 2).

  Patent Documents 3 and 4 propose a printing ink composition comprising rosin-modified phenolic resin and vegetable oil ester as solvent main components, significantly reducing VOC components compared to conventional inks, and having high-speed setting properties. However, the drying property is insufficient.

In Patent Document 5, rosin-modified phenolic resin, rice bran oil and fatty acid monoester are used as main raw materials, and VOC components are greatly reduced compared to conventional inks. Printing inks with stability have been proposed, but this is also insufficient with respect to drying properties.

Regarding the transition of pigment components to biological resources, the current situation is that the transition to biological resources has not progressed due to problems such as dispersibility, coloring power, hue, gloss, emulsification suitability, etc. It is common to use fossil resource-derived carbon black that has a large environmental burden but good dispersibility and coloring power. Therefore, various examinations have been made from the viewpoint of reducing the environmental load in the method for producing fossil resource-derived carbon black.

The fossil resource-derived carbon black production method includes the channel method, oil furnace method, gas furnace method, acetylene method, etc. From the viewpoint of mass productivity and high yield, the oil furnace method is used for oxidation polymerization type offset ink. Although it is the mainstream of black pigments, it is not preferable for the environment because it uses a large amount of fossil resources as raw materials because it is produced by incomplete combustion of coal-based and petroleum-based feedstock in high-temperature gas.

Patent Document 6 proposes a method for producing fossil resource-derived carbon black by a channel method that is efficient in a pollution-free environment, compared to a channel method that is problematic in terms of yield and working environment. Since there is no change in using fossil resources, it is unfavorable to the environment, and costs are increased compared to the oil furnace method, which is not practical.

Patent Document 7 proposes a method for producing fossil resource-derived carbon black in which a part of coal-based and petroleum-based feedstock used in the oil furnace method is replaced with animal or vegetable oil or a modified product thereof. Although it is effective in reducing the environmental load, it is not preferable because it causes deterioration of drying properties.

  On the other hand, cost increases due to soaring materials are also a problem, and it is desirable to replace some of the materials with biological resources from the viewpoint of cost control.

In recent years, there has been a movement to reuse thinned wood as a biomass resource from the viewpoint of reducing environmental load and preventing environmental pollution, and a part of the thinned wood is used as paper, wood board or fuel.

  However, because the application is limited, it cannot be reused due to the fact that the amount of materials used is small and it is too expensive to regenerate into materials, and a considerable amount of thinned wood is burned or discarded is the current situation. In addition, it is desirable to effectively use post-combustion materials such as bamboo ink and charcoal from the viewpoint of reducing environmental burden and preventing environmental pollution.

In addition, lignin separated in large quantities when producing pulp in paper mills and the like is said to occupy about 30% of plant components and is said to be the most abundant aromatic polymer biomass on the earth. However, at present, the advanced technology of lignin is hardly established, and it is used as a fuel for private power generation in paper mills, or only a part is used as a fragrance. Has been. In addition, there are various types of plant biomass that is not effectively utilized other than lignin, such as soybean seed coat, and more effective utilization of these will lead to reduction of environmental burden and prevention of environmental pollution. The technology is not established yet.

JP 2006-249385 A JP 2005-290084 A JP 2002-69354 A JP 2002-155227 A JP 2005-330317 A Japanese Patent Laid-Open No. 06-057170 JP 2009-024071 A

  The present invention provides an offset ink composition excellent in the fluidity and temporal stability of ink, the drying property during printing, and the stability on the printing press while taking into consideration the global environment, and a printed matter using the same. It is.

  As a result of sincere research to solve the above problems, in the offset ink composition containing fossil resource-derived carbon, binder resin, vegetable oil, and petroleum solvent, the offset ink composition containing a specific carbon black has fluidity and The inventors have found that the stability over time, the drying property during printing, and the stability on the printing press are excellent, and the present invention has been completed.

That is, the present invention relates to an oxidation polymerization type offset ink composition containing carbon having a spherical or spheroidal particle shape, carbon having a particle shape other than a spherical or spheroidal shape, a binder resin, a vegetable oil, and a petroleum solvent. In things,
Carbon having a particle shape other than a spherical or spheroid shape is obtained by dry pulverizing bamboo charcoal carbide,
Median diameter 0.5 μm to 10 μm
and
80% of the particle diameter is 15 μm or less and the total amount of carbon having a spherical or spheroid particle shape
10-30% by weight
Contains, and
Binder resin
Acid value 5-30 (mgKOH / g),
Softening point 120-300 ° C by ring and ball method
And a weight average molecular weight of 10,000 to 100,000
The present invention relates to an oxidation polymerization type offset ink composition characterized by being a rosin-modified phenol resin.

Further, the present invention provides the above oxidation polymerization offset ink composition, wherein the carbon having a particle shape other than a spherical shape or a spheroid shape has a loose apparent specific gravity of 0.03 to 0.3 g / cm ³ . It is about.

Further, the present invention is an oxidation polymerization offset ink composition further containing a petroleum solvent in the oxidation polymerization offset ink composition according to any one of the above,
Petroleum solvents
Aniline point 75-95 ° C
And boiling point 260-350 ° C
It is related with the oxidation polymerization type offset ink composition characterized by these.

Furthermore, this invention relates to the printed matter formed by printing on the base material any one of the said oxidation polymerization type offset ink compositions.

  The oxidative polymerization type offset ink composition provided by the present invention is excellent in fluidity and aging stability of ink, drying property at the time of printing and stability on a printing press in printing of books, books, leaflets, catalogs, etc. Excellent and less environmental impact.

  Next, the present invention will be described more specifically with reference to preferred embodiments.

Examples of carbon having a spherical or spheroid particle shape used in the present invention include fossil resource-derived carbon black. Examples of the production method include a channel method, an oil furnace method, a gas furnace method, an acetylene method, and the like. It is done. These are produced by incomplete combustion of coal-based and petroleum-based feedstocks in high-temperature gas, so they are unfavorable to the environment in terms of using large amounts of fossil resources as raw materials, and some of these are generated from biological resources. Replacing it with biomass carbon that has been released will lead to a reduction in environmental impact.

In general, carbon used in oxidation polymerization offset ink is primary (basic)
It is said that spherical carbon particles called particles are fused to form an agglomerated form branched into chained or irregular chains, forming an agglomerate similar to a bunch of grapes. The carbon having a spherical or spheroidal particle shape used has a ratio of the shortest diameter / longest diameter of particles (hereinafter abbreviated as true sphere ratio) of about 0.6 to 1.0 when observed with a scanning electron beam. A spheroidal particle image is obtained.

As the carbon having a spherical or spheroid particle shape used in the present invention, any carbon can be used according to the characteristics of the printing paper, but the DBP oil absorption defined in accordance with JIS K6217-4 is 50. It is preferable that it is -120cm < ³ > / 100g. Also,
The nitrogen adsorption specific surface area defined in accordance with JIS K6217-2 is preferably 60 to 130 m ² / g or less. Furthermore, the addition amount of the fossil resource-derived carbon black of the present invention is preferably 10 to 25% by weight in the printing ink.

The carbon having a particle shape other than a spherical or spheroid used in the present invention is obtained by dry-pulverizing a charcoal such as bamboo ink or charcoal, or refined as necessary, or thinned wood, plant seed coat or plant This refers to a product obtained by carbonizing the constituent lignin and collecting the obtained carbide and the soot obtained when carbonized, and if necessary, dry pulverizing and purifying. For example, it can be obtained by dry-pulverizing a thinned wood by heating it to a high temperature by a steam activation method and carbonizing it. When these are observed with a scanning electron beam, a particle image other than a spherical shape or a spheroid shape is obtained.

Carbon having a particle shape other than spherical or spheroid used in the present invention preferably has a median diameter of 0.5 μm to 10 μm and an 80% particle diameter of 15 μm or less, more preferably a median diameter of 1.0 μm. ˜8 μm, and 80% particle size is 12 μm or less,
More preferably, the median diameter is 1.0 μm to 6 μm, and the 80% particle diameter is 8 μm or less. If the median diameter is less than 0.5 μm, the load in the dry pulverization process during the production of carbon having a particle shape other than spherical or spheroid is increased, which is not preferable. The median diameter is more than 10 μm. If it is large, the load in the dispersion process during ink production increases, which is not preferable. On the other hand, if the 80% particle size is larger than 15 μm, the number of coarse particles is so large that it is difficult to disperse, resulting in deterioration of ink dispersion stability and deterioration of gloss on the printing paper surface.

In general, the loose apparent specific gravity is the specific gravity at the time of loose filling, that is, the apparent specific gravity of a granular material containing a large amount of air that is dropped by an injection method and received in a container. The loose apparent specific gravity in the present invention was measured using a powder characteristic evaluation apparatus (powder tester PT-R type). A dispersion sieve having an opening of 1700 μm was used.

The carbon having a particle shape other than a spherical or spheroid used in the present invention preferably has a loose apparent specific gravity of 0.03 to 0.3 g / cm ³ , more preferably 0.0.
5~0.25g / cm ^3, further preferably at 0.1 to 0.2 g / cm ^3. A loose apparent specific gravity of less than 0.03 g / cm ³ is not preferable because the powder is likely to fly in the preparation process at the time of ink production and the yield and the surrounding work environment deteriorate. If the loose apparent specific gravity is larger than 0.3 g / cm ³ , it is not preferable because the diffusion into the dispersion medium becomes rough and the load during the dispersion step becomes large in the step of mixing the materials charged at the time of ink production.

Further, the carbon having a particle shape other than the spherical or spheroid shape used in the present invention is preferably contained in an amount of 10 to 35% by weight, more preferably based on the carbon having a spherical or spheroid particle shape. It is desirable to contain 15 to 30% by weight, more preferably 17 to 27% by weight. Less than 10% by weight with respect to carbon having a spherical or spheroid particle shape is not preferable because the stability of the ink on the printing press is inferior, increasing the tack, increasing the viscosity of the ink, and lowering the fluidity. If it is more than 30% by weight, it is not preferable because it causes deterioration of dispersibility and fluidity.

  In the present invention, the vegetable oils include vegetable oils and compounds derived from vegetable oils. As the compound, for example, in a triglyceride of glycerin and a fatty acid, at least one fatty acid is a fatty acid having at least one carbon-carbon unsaturated bond. Examples include fatty acid monoesters obtained by ester reaction of triglycerides with saturated or unsaturated alcohols from these triglycerides, fatty acid monoesters obtained by direct ester reaction of fatty acids of vegetable oils and monoalcohols, and ethers.

  In the present invention, as required, for example, cane seed oil, linseed oil, eno oil, prickly oil, olive oil, cacao oil, kapok oil, kayak oil, mustard oil, kyounin oil, kiri oil, kukui oil, walnut oil, poppy oil , Sesame oil, safflower oil, radish seed oil, soybean oil, regenerated soybean oil, rapeseed oil, rice salad oil, garlic oil, camellia oil, corn oil, rapeseed oil, niger oil, nuka oil, palm oil, castor oil, sunflower oil , Grape seed oil, gentian oil, pine seed oil, cottonseed oil, coconut oil, peanut oil, dehydrated castor oil, etc. Can be used alone or in combination of two or more, but is preferably 20% by weight or less, more preferably 10% by weight or less, based on the total amount of the offset ink composition. It is desirable to content of. When used in an amount of 10% by weight or more, it is not preferable because the temporal stability of the ink in the storage container is inferior.

  Examples of binder resins that can be used in the present invention include phenolic resins (phenolic resins, rosins, cured rosins, rosin-modified phenolic resins using polymerized rosins, etc.), maleic acid resins (rosin-modified maleic acid, etc.). Resin, rosin ester resin and the like), alkyd resin or modified alkyd resin, petroleum resin and the like, and these can be used alone or in combination of two or more.

  In particular, the binder resin preferably used in the present invention has an acid value of 5 to 30 (mg KOH / g), a weight average molecular weight of 10,000 to 100,000, preferably 20,000 to 80,000, and a softening point by a ring and ball method of 120 to 120. A rosin-modified phenolic resin having a temperature of 300 ° C., preferably 120 to 280 ° C. is desirable. When the weight average molecular weight is 10,000 or less, the viscoelasticity of the ink is lowered, and when it is 100,000 or more, the fluidity and gloss of the ink are inferior.

The rosin-modified phenolic resin in the present invention is obtained by reacting rosin which is a resin acid, resole which is a condensate of alkylphenol and formalin, and a polyhydric alcohol, and a third component such as maleic acid is added as necessary. Sometimes. The blending ratio of rosin and resole is one of the important factors controlling the physical properties of the resin. The blending ratio of rosin in the rosin-modified phenolic resin according to the present invention is desirably 60% by weight or more and 70% by weight or less, and preferably 62% by weight or more and 67% by weight or less. If the ratio is less than 60% by weight, the resole has excessive alkyl groups. As a result, the solubility of the resin in the solvent becomes excessive, making it difficult to achieve the desired high viscosity of the ink. Since the alkyl group of the resole is reduced and the solubility of the resin in the solvent is too bad, the solvent may be separated from the ink.

  The petroleum solvent used in the present invention is a crude oil-derived solvent (petroleum solvent) having an aromatic hydrocarbon content of 1% by weight or less, and has a boiling point of 260 to 350 ° C, preferably 280 to 340 ° C. The thing in the range of ° C is good. When the boiling point of petroleum-based solvents is less than 260 ° C, the solvent evaporation of the ink on the printing machine increases, and the transferability of the ink to rollers, blankets, plates, etc. deteriorates due to the deterioration of the fluidity of the ink. It is not preferable. Further, when the boiling point of the petroleum solvent used in combination exceeds 350 ° C., the drying property of the ink is inferior. The petroleum solvent used in the present invention is desirably contained in an amount of 5 to 20% by weight, preferably 7 to 18% by weight, based on the total amount of the ink, if necessary.

  Further, an aniline point of 75 ° C to 95 ° C is suitable for the petroleum solvent. When the aniline point is less than 75 ° C., the ability to dissolve the resin is too high, the ink viscosity becomes too low, and the stain resistance is not sufficient. Also, if the aniline point exceeds 95 ° C, the ability to dissolve the resin is too low, the ink viscosity becomes too high, the ink fluidity is poor, and ink tends to accumulate on the rollers, plates, and blankets. Therefore, it is not preferable.

  Furthermore, the offset ink composition of the present invention includes a gelling agent, a pigment dispersant, a metal dryer, a drying inhibitor, an antioxidant, a friction improver, an anti-set-off agent, and a nonionic sea surface activity as required. Additives such as agents and polyhydric alcohols can be used as appropriate.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, the scope of the present invention is not limited by these Examples. In the present invention, “part” means “part by weight” and “%” means “% by weight” unless otherwise specified.

<Measurement method of viscosity>
HAAKE Rheostress 600 (Thermo ELECTRON CORP
The viscosity at 25 ° C. and the shear rate of 117 / s by ORATION was determined as the viscosity in the present invention.

(Phenolic resin production example 1)
P-octylphenol 1000 parts, 35% formalin 850 parts, 93% sodium hydroxide 60 parts and toluene 1000 parts were added to a four-necked flask equipped with a stirrer, cooler and thermometer, and reacted at 90 ° C. for 6 hours. It is dripping. Thereafter, 125 parts of 6N hydrochloric acid and 1000 parts of tap water were added, stirred and allowed to stand, and the upper layer part was taken out to obtain 2000 parts of a toluene solution of a resol type phenol resin having a nonvolatile content of 49%. Y.

(Production Example 1 of rosin-modified phenolic resin)
A four-necked flask equipped with a stirrer, a condenser with a water separator, and a thermometer was charged with 1000 parts of gum rosin, dissolved at 200 ° C. while blowing nitrogen gas, and 1360 parts of resole liquid Y was added to remove toluene. Then, after reacting at 230 ° C. for 4 hours, 100 parts of glycerin was added and esterified at 250 to 260 ° C. until the acid value was 25 or less, and a rosin having a weight average molecular weight of 28000, an acid value of 21.7 and a softening point of 170 ° C. A modified phenolic resin A (hereinafter referred to as “resin A”) was obtained.

(Production Example 2 of rosin-modified phenolic resin)
A four-necked flask equipped with a stirrer, a condenser with a water separator and a thermometer was charged with 1000 parts of gum rosin, dissolved at 200 ° C. while blowing nitrogen gas, and 1490 parts of resole liquid Y was added to remove toluene. Then, after reacting at 230 ° C. for 4 hours, 115 parts of glycerin was charged and esterified at 250 to 260 ° C. until an acid value of 25 or less, and a rosin having a weight average molecular weight of 60000, an acid value of 19.5, and a softening point of 180 ° C. Modified phenol resin B (hereinafter referred to as resin B) was obtained.

(Production Example 3 of rosin-modified phenolic resin)
A four-necked flask equipped with a stirrer, a condenser with a water separator, and a thermometer was charged with 1000 parts of gum rosin, dissolved at 200 ° C. while blowing nitrogen gas, and 1370 parts of resole liquid Y was added to remove toluene. Then, after reacting at 230 ° C. for 4 hours, 130 parts of glycerin was charged and esterified at 250 to 260 ° C. until the acid value was 25 or less, and a rosin having a weight average molecular weight of 140000, an acid value of 18.5 and a softening point of 190 ° C. A modified phenolic resin C (hereinafter referred to as “resin C”) was obtained.

(Manufacture of varnish)
Stirrer, Liebig condenser, 4-neck flask with thermometer, 44 parts of resin A (weight average molecular weight 28000, acid value 21.7, softening point 170 ° C.), 38 parts of vegetable oil, AF Solvent No. 6 (Shin Nippon Oil ( Co., Ltd.) 17 parts and ALCH (Kawaken Fine Chemical Co., Ltd. gelling agent) 1 part were charged, heated to 190 ° C., stirred at the same temperature for 1 hour, and then allowed to cool to obtain varnish 1.

Furthermore, based on the composition in Table 1, gel varnishes 2 and 3 for heat set-off wheel ink (hereinafter referred to as varnishes 2 and 3) were obtained by the same gel varnish production method as above. Table 1
The respective weight average molecular weight, acid value, and softening point are shown in the figure.

The particle size distribution of carbon 1 having a particle shape other than a spherical shape or spheroidal shape derived from bamboo ink is measured by a laser diffraction / scattering type particle size distribution measuring device (LA-920, manufactured by Horiba, Ltd .;
LY-208 dry measurement unit specification), the median diameter is 3.78 μm.
m, and the 80% particle size was 5.43 μm. Furthermore, when the apparent specific gravity of the looseness was measured using a powder tester PT-R type manufactured by Hosokawa Micron Corporation, 0.275 was obtained.
g / cm ³ . Further, an analytical scanning electron microscope (JSM-6390LA type manufactured by JEOL)
When the particle shape was measured at a magnification of 2000 times, it had a particle shape other than a spherical shape or a spheroid shape.

The same applies to carbons 2 to 7 having a particle shape other than a spherical or spheroid shape and carbon black MA11 for Mitsubishi color (manufactured by Mitsubishi Chemical Corporation, carbon having a spherical or spheroid particle shape). Table 2 shows the median diameter, 80% particle diameter, apparent specific gravity of looseness, and particle shape measured by the measurement method. Table 2 shows carbon products derived from particles having particle shapes other than spherical or spheroid shapes.

(Base ink and ink manufacturing)
Carbon black MA11 for Mitsubishi color 17 parts, carbon 1 having a shape other than spherical or spheroid, 5 parts, gel varnish 1 60 parts, total 82 parts on 3 rolls, 3 rolls at 60 ° C. When the meat was kneaded 4 times, the pigment particles were dispersed to 7.5 μm or less, and the base ink 1 was obtained.
Next, 14 parts of AF solvent 6 for base ink 1, 2 parts of anti-friction compound (New anti-friction compound made by Toyo Ink Manufacturing Co., Ltd.), 1.5 parts of metal dryer (MK dryer made by Toyo Ink Co., Ltd.) Then, 0.5 part of a drying inhibitor (Drying inhibitor CP manufactured by Toyo Ink Co., Ltd.) was added to obtain about 100 parts by weight of the ink of Example 1.

A base ink was prepared by the same base ink preparation method as described above, with the formulation shown in Table 3, and about 100 parts of inks of Examples 2 to 6 and Comparative Examples 1 to 6 were obtained. Table 3 shows the weight% of carbon, varnish, compound, and AF Solvent No. 5 having a shape other than carbon black, sphere, or spheroid contained in the inks of Examples 1 to 6 and Comparative Examples 1 to 6. Show. In addition, the weight percentage of carbon having a shape other than a sphere or spheroid with respect to carbon black and the number of times of kneading required to disperse the base ink to 7.5 μm or less are shown.
The smaller the number of beats, the better the dispersibility, and the more the number of beats, the worse the dispersibility.

(Evaluation results)
The sheet-fed inks of Examples 1 to 6 and Comparative Examples 1 to 6 were evaluated for fluidity, drying property, on-machine stability, and stability over time, and the results are shown in Table 4, respectively.

<Measurement method of fluidity>
After setting 2.1 cc of ink in a hemispherical container and allowing it to stand at 40 ° C. for 1 hour, the ink was dropped on an inclined plate inclined at 60 °, and the length of flow for 10 minutes was measured. Evaluation was performed based on the following evaluation criteria.
(Evaluation criteria)
◎: 80 mm or more ○: 70 mm or more, less than 80 mm Δ: 50 mm or more, less than 70 mm ×: less than 50 mm

<Method of measuring dryness>
The ink was developed on coated paper by using an RI tester (manufactured by Meiko Seisakusho Co., Ltd.), and sulfuric acid paper was layered on the developed surface. The drying time was the time when the ink no longer adhered to the sulfuric acid paper, and the evaluation was performed based on the following evaluation criteria.
(Evaluation criteria)
◎: Less than 6 hours ○: 6 hours or more, less than 8 hours △: 8 hours or more, less than 10 hours ×: 10 hours or more

<Measurement method of on-board stability>
After the ink was developed on a glass plate with a 75 μm applicator, the drying time was examined by finger touch every 30 minutes under conditions of 40 ° C. and humidity of 52%. The drying time was the time when the ink no longer adhered to the finger, and the evaluation was performed based on the following evaluation criteria.
(Evaluation criteria)
◎: 12 hours or more ○: 10 hours or more, less than 12 hours △: 6 hours or more, less than 10 hours ×: Less than 6 hours

<Measurement method of stability over time>
The ink viscosity (Pa · s) at 25 ° C. and a share rate of 117 / s was measured by HAAKE Rheopress 600 (manufactured by Thermo ELECTRON CORPORATION). Then, it put into the airtight container, purged with nitrogen, closed the lid | cover, and stored in 90 degreeC oven for 1 week. After one week, the ink was removed from the oven and the ink viscosity was measured again. The difference in ink viscosity before and after oven storage was determined and evaluated based on the following evaluation criteria. The smaller the amount of change in viscosity, the better the stability over time.
(Evaluation criteria)
◎: Less than 10 Pa · s ○: 10 Pa · s or more, less than 15 Pa · s Δ: 15 Pa · s or more, less than 20 Pa · s ×: 20 Pa · s or more

  From the results of Table 4, it was found that the fluidity, drying property, on-machine stability, and stability over time were all well balanced and excellent.

In addition, as a result of performing a printing test of the offset ink composition of the example under the following conditions using a Lithlon 426 sheet-fed printing press (manufactured by Komori Corporation), printing was possible without problems and good printed matter was obtained.
(Printing conditions)
Version: CTP plate for flat plate HP-F (Fuji Film Graphic Systems Co., Ltd.)
Dampening water: AQUAUNITY C 2.0% (Toyo Ink Manufacturing Co., Ltd.)
Paper: Art paper (Mitsubishi Paper)
Printing speed: 8000 sheets / hour

  The oxidation polymerization type offset ink according to the present invention is superior in the fluidity and aging stability of the ink as compared with the conventional ones, and is excellent in drying property and stability on the printing press, and has less environmental impact, such as books, flyers and catalogs. Is useful in the field of printing.

Claims (4)

In the oxidation polymerization type offset ink composition containing carbon having a spherical or spheroid particle shape, carbon having a particle shape other than spherical or spheroid shape, binder resin, vegetable oil and petroleum solvent,
Carbon having a particle shape other than a spherical or spheroid shape is obtained by dry pulverizing bamboo charcoal carbide,
Median diameter 0.5 μm to 10 μm
and
80% of the particle diameter is 15 μm or less and the total amount of carbon having a spherical or spheroid particle shape
10-30% by weight
Contains, and
Binder resin
Acid value 5-30 (mgKOH / g),
Softening point 120-300 ° C by ring and ball method
And a weight average molecular weight of 10,000 to 100,000
An oxidation polymerization type offset ink composition characterized by being a rosin-modified phenol resin.   2. The oxidation polymerization type offset ink composition according to claim 1, wherein the carbon having a particle shape other than a spherical shape or a spheroid shape has a loose apparent specific gravity of 0.03 to 0.3 g / cm <3>. An oxidation polymerization type offset ink composition further comprising a petroleum solvent in the oxidation polymerization type offset ink composition according to claim 1 or 2,
Petroleum solvents
Aniline point 75-95 ° C
And boiling point 260-350 ° C
An oxidation polymerization type offset ink composition characterized by   The printed matter formed by printing the oxidation polymerization type offset ink composition in any one of Claims 1-3 on a base material.