JP2010241866A - Lithographic printing ink and printed matter printed using the same - Google Patents

Abstract

（式中、Ｒ^１、Ｒ^２は直鎖状のアルキル基を示す。）
【選択図】なし[PROBLEMS] It relates to ink for lithographic printing. It supports high printing speed and low quality printing paper, and has good dryness, on-machine stability, paper peelability, gloss, etc., and is environmentally friendly. A lithographic printing ink is provided.
A lithographic printing ink which is an offset rotary printing ink comprising a compound represented by the general formula (1), a rosin-modified phenolic resin and a vegetable oil component, and further printing the lithographic printing ink on a substrate. To print.

(In the formula, R ¹ and R ² represent a linear alkyl group.)
[Selection figure] None

Description

  The present invention relates to a lithographic ink used for offset rotary printing.

  Conventionally, lithographic printing inks are composed of pigments, resins, petroleum-based solvents, vegetable oils, and the like. In addition, lithographic printing using lithographic printing ink is known for various drying methods such as heat-set drying used for offset rotary printing, osmotic drying and oxidation polymerization drying used for offset sheet-fed printing and newspaper printing. In particular, the heat-set type drying fixes the lithographic printing ink on the surface of the printing paper by passing the petroleum solvent in the lithographic printing ink through the dryer immediately after printing and forcibly evaporating the solvent ( Set). Heat-set type offset rotary printing is the mainstream printing method at present because the lithographic printing ink is set in a short time at a high speed by a dryer. Petroleum solvents used in lithographic printing inks are mainly AF (aroma-free) solvents with aromatic components kept to 1% or less, and heat set offset rotary printing requires appropriate evaporation speed and drying properties. Therefore, a solvent having a low boiling point range is used as compared with a solvent used for permeation type dry sheet printing or newspaper printing. For example, AF solvent 7 (manufactured by Shin Nippon Oil Co., Ltd.) having a boiling point range of 259 to 282 ° C. is often used for heat-set offset rotary ink. For sheet-fed printing inks, AF solvent 6 (manufactured by Shin Nippon Oil Co., Ltd.) having a boiling range of 296 to 317 ° C. and AF solvent 5 (manufactured by Shin Nippon Oil Co., Ltd.) having a boiling point range of 275 to 306 ° C. Is often used. Further, even an AF solvent contains at least a VOC component.

  Therefore, in heat-set offset rotary printing, the solvent is evaporated and the lithographic printing ink is dried, so that evaporation of a volatile organic compound, so-called VOC (Volatile Organic Compound) component, occurs. In sheet-fed printing, the solvent in the lithographic printing ink permeates and then gradually oxidatively polymerizes to dry and adhere. However, even when the AF solvent is used, the VOC component evaporates into the atmosphere.

  In the recent printing industry, there is a demand to reduce the environmental load by suppressing the discharge of VOC components, aromatic components, and naphthenic components contained in lithographic printing inks. Therefore, from AF solvents to vegetable oil components that do not contain VOC components There is a lithographic printing ink from which VOC components are removed by conversion. However, since the vegetable oil component has a higher viscosity than the AF solvent, the penetrability is poor and the setting property is delayed. Moreover, since the ratio of a vegetable oil component increases, since it tends to remain in printed matter, it will affect dryness. In addition, since the solvent that tends to evaporate is converted to a vegetable oil component that is difficult to evaporate, it is not possible to completely convert it to a vegetable oil component in heat-set offset rotary ink that is dried by forcibly evaporating the solvent with a dryer. However, it is realized only with a sheet-fed lithographic printing ink used for osmotic drying type offset sheet-fed printing.

  At present, at the printing site for heat-set type offset rotary printing, an exhaust gas treatment device is installed to reduce VOC emissions from the dryer to reduce the environmental load, and the dryer is used to reduce the energy required for drying. While printing is performed at a temperature as low as possible, inexpensive and low-quality printing paper is being used to increase printing speed and reduce printing costs in order to improve productivity. For this reason, it has fallen into a dilemma in which the image quality of the printed matter is reduced due to stains due to poor drying, paper peeling, blanking, gloss reduction, and the like.

  Contamination due to poor drying may occur when the drying temperature of the dryer is low or the printing speed is high, and the set of lithographic printing ink printed on printing paper is not sufficient and rubs in the dryer. It is transferred to the cooling roller and gradually accumulates and becomes dirty, or it is rubbed with a guide roller, turn bar, triangular plate, folding machine, etc. due to insufficient surface strength of the lithographic printing ink film.

  Peeling occurs when cheap and low-quality printing papers are used, and they tend to occur when the paper surface strength is weak and the tackiness of the lithographic printing ink is high, and when the printing speed is high, the lithographic printing Increasing the apparent tack of the printing ink tends to occur.

  Blanking is a phenomenon in which ink with increased adhesiveness gradually accumulates on a blanket. However, if the solubility of lithographic printing ink is high, the increase in tack over time (tack increase width ΔT) increases. It is also said that the stability is poor. Paper peeling is likely to occur due to this phenomenon.

In order to cope with higher printing speeds, high-molecular weight resins are used in lithographic printing inks. However, such resins generally have low solubility and quicker solvent detachment, so that setability is improved. Is improved, but the fluidity and gloss of the lithographic printing ink are reduced.
Further, in order to suppress rubbing stains due to poor drying, a wax may be used in the lithographic printing ink, but the compatibility between the wax and the lithographic printing ink is deteriorated, and the gloss is lowered.

  Patent Document 1 discloses a heatset type lithographic offset printing ink composition that is excellent in friction resistance by using a wax to increase the surface strength of a printing ink film after drying and has a low gloss reduction. However, in order to maintain friction resistance, the drying temperature cannot be lowered below the melting point of the wax.

  Patent Document 2 discloses an offset rotary printing ink that has an excellent balance between the evaporation and drying properties of the ink and the on-machine stability by replacing all or part of the petroleum solvent with a fatty acid ester. There is no detailed explanation about paper peeling.

  Patent Document 3 discloses a penetrating dry offset printing ink for lower paper printing which uses a vegetable oil component instead of a petroleum solvent and solves the problem of paper peeling by using an ultra-high molecular weight low-solubility resin. Although disclosed, gloss is reduced.

JP 2003-221536 A JP 2006-176754 A JP 2008-156429 A

  Patent Document 1 aims to prevent rubbing stains due to poor drying by improving the strength of the ink film with wax, but is merely an addition to conventional inks, and does not mention resins or solvents. There is no explanation. Further, when the drying temperature is lowered below the melting point of the wax, it is expected that rubbing stains will occur. Patent Document 2 aims to replace all or part of the petroleum solvent with a fatty acid ester to balance drying and machine stability. However, if the molecular weight of the fatty acid ester is increased, the boiling point is also increased. Although it is easily expected to be high and the on-machine stability is improved, the drying temperature must be high. In addition, since the fatty acid ester has high ink solubility, the viscosity of the varnish decreases, causing excessive fluidity and a decrease in yield value. In Patent Document 3, since it is an ultra-high molecular weight resin, it is necessary to reduce the amount of the resin and to add a large amount of the vegetable oil accordingly, so that the tack is lowered and the paper is effectively removed, but it is difficult to evaporate. Since a large amount of vegetable oil is used, it is limited to penetrating and drying inks for rough paper such as newsprint. In addition, it must be understood that a reduction in gloss occurs due to its low solubility.

  Therefore, the present invention is compatible with higher printing speeds and lower printing paper quality, and has excellent drying properties, on-machine stability, paper peelability, gloss, etc. It is to provide.

  In light of the problems of the prior art, the present inventors have conducted extensive research and found that the above object can be achieved by a lithographic printing ink having a specific composition, and have completed the present invention.

（式中、Ｒ^１、Ｒ^２は直鎖状のアルキル基を示す。）
（２）前記一般式（１）で表される化合物において、Ｒ^１の炭素数が８〜１２であり、かつＲ^２の炭素数が１０〜１４である上記（１）に記載の平版印刷用インキ、
（３）前記ロジン変性フェノール樹脂の軟化点が１５０〜２２０℃の範囲内で、かつ重量平均分子量が１２０，０００〜３００，０００の範囲内である上記（１）または（２）のいずれかに記載の平版印刷用インキ、
（４）前記植物油成分が、大豆油または大豆油由来の脂肪酸エステルである上記（１）〜（３）のいずれかに記載の平版印刷用インキ、
（５）平版印刷用インキが、オフセット輪転印刷用インキである上記（１）〜（４）のいずれかに記載の平版印刷用インキ、
（６）基材上に上記（１）〜（５）のいずれかに記載の平版印刷用インキを用いて印刷した印刷物、
である。 That is, the present invention
(1) A lithographic printing ink comprising a compound represented by the general formula (1), a rosin-modified phenolic resin and a vegetable oil component,

(In the formula, R ¹ and R ² represent a linear alkyl group.)
(2) In the compound represented by the general formula (1), a number of carbon atoms of ^{R 1} is 8 to 12, and for lithographic printing according to (1) the number of carbon atoms in ^{R 2} is 10 to 14 ink,
(3) The softening point of the rosin-modified phenolic resin is in the range of 150 to 220 ° C. and the weight average molecular weight is in the range of 120,000 to 300,000, either (1) or (2) Lithographic printing ink as described,
(4) The lithographic printing ink according to any one of the above (1) to (3), wherein the vegetable oil component is soybean oil or a fatty acid ester derived from soybean oil,
(5) The lithographic printing ink according to any one of the above (1) to (4), wherein the lithographic printing ink is an offset rotary printing ink,
(6) Printed matter printed on the base material using the lithographic printing ink according to any one of (1) to (5) above,
It is.

  According to the lithographic printing ink of the present invention, it is possible to improve the printability such as drying property, on-machine stability, reduction of paper peeling, etc., and by using the lithographic printing ink, high gloss image quality can be achieved. High prints can be provided. Furthermore, an environment-friendly lithographic printing ink and printed matter that can remove volatile components from the lithographic printing ink can be provided.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. Note that this embodiment is merely an embodiment for carrying out the present invention, and the present invention is not limited by this embodiment, and various modified embodiments can be made without departing from the gist of the present invention. Is possible.

  The lithographic printing ink according to the present invention comprises a compound represented by the following general formula (1), a rosin-modified phenolic resin, and a vegetable oil component. Other resins, additives, solvents and the like can be used as necessary.

（式中、Ｒ^１、Ｒ^２は直鎖状のアルキル基を示す。）

(In the formula, R ¹ and R ² represent a linear alkyl group.)

  The compound represented by the general formula (1) of the present invention is obtained by a dimerization reaction of an α-olefin (hereinafter referred to as “vinylidene olefin” in the present specification).

  As the α-olefin, those having 10 to 14 carbon atoms are preferable. For example, 1-decene, 1-dodecene, 1-tetradecene and the like can be mentioned. Of these, 1-decene having 10 carbon atoms is particularly preferable.

As the vinylidene olefin, in the general formula (1), a number of carbon atoms of ^{R 1} is 8 to 12, and the number of carbon atoms in ^{R 2} is preferably from 10 to 14. For example, 2-octyl-1-dodecene, 2-decyl-1-tetradecene, 2-dodecyl-1-hexadecene and the like can be mentioned. Among them, particularly preferred is 2-octyl-1-dodecene in which R ¹ has 8 carbon atoms and R ² has 10 carbon atoms in general formula (1). These are high-boiling, low-viscosity liquids having low-temperature fluidity, high permeability, and improved setability.

  An α-olefin having a carbon number similar to that of 2-octyl-1-dodecene, which is a vinylidene olefin having 20 carbon atoms, has a high boiling point, but is highly viscous or waxy at room temperature, so it can be used at low temperatures. Is not suitable and has a drawback of poor setability due to poor permeability.

In the general formula (1), if the carbon number of R ¹ is less than 8 and the carbon number of R ² is less than 10, the flash point is lowered, which is not appropriate. A tetramer of α-olefin (for example, 13-methyl-11,13-dioctyl-10-tricosene) or higher carbon number is produced because the molecular weight increases and the solvent viscosity increases accordingly. It is not appropriate because of poor aptitude and ink suitability.

  Furthermore, a vinylidene olefin does not contain a VOC component, an aromatic component, and a naphthene component. By not containing the VOC component, the AF solvent is replaced with vinylidene olefin, and the ink for offset rotary printing is used, so that there is no discharge or scattering of the VOC component into the atmosphere even when passing through a dryer during printing. Among them, 2-octyl-1-dodecene has a high boiling point of 330 ° C. and less solvent removal on the printing press, so that the on-board stability is improved and the tack increase width ΔT is also small. Hateful. Furthermore, it can be preferably used as an alternative to the AF solvent 6, which is often used for sheet-fed printing ink. Although the AF solvent 6 has the same boiling point, since the solvent is quickly removed from the printing press, the stability on the press is inferior and the tack increase width ΔT is increased, so that paper peeling is likely to occur. .

The definition of VOC refers to the classification of chemical substances of the World Health Organization (WHO) according to the certification standards for printing ink by the Eco Mark business of the Japan Environment Association. Volatile organic compounds classified as "organic compounds", "highly volatile organic compounds" refers to those whose boiling range is measured at <0 ° C to 50-100 ° C, and "volatile organic compounds" The boiling point range refers to that measured at 50-100 ° C to 240-260 ° C.
Further, according to the Air Pollution Control Law, it is an organic compound that is a gas when discharged or scattered in the atmosphere.
According to the Green Printing Certification System of the Japan Printing Industry Federation, VOC content of less than 1% is non-VOC ink (except for rotary ink), and is a certification standard for sheet-fed ink only.

  Since the vinylidene olefin of the present invention has a high boiling point and does not contain a VOC component, it can be used for offset rotary printing ink, and even if it is passed through a dryer during printing, the VOC component is discharged into the atmosphere and scattered. Therefore, it does not meet the above-mentioned Eco Mark certification standards and the VOC definition of the Air Pollution Control Act. In the green printing certification system, only the sheet-fed printing ink is certified, but it can also be realized with rotary ink by using the vinylidene olefin of the present invention.

  The vinylidene olefin content in the lithographic printing ink of the present invention is preferably in the range of 5 to 40% by weight. Among these, the range of 10 to 35% by weight is particularly preferable. If it is less than 5% by weight, the tackiness of the lithographic printing ink does not decrease, the paper is easily peeled off, and the stability on the machine is lowered. When it exceeds 40% by weight, the gloss and the inking property are deteriorated, and the printed matter is inferior in image quality.

  The rosin-modified phenolic resin of the present invention preferably has a softening point in the range of 150 to 220 ° C. and a weight average molecular weight in the range of 120,000 to 300,000. Among these, a softening point is particularly preferably in the range of 180 to 200 ° C., and a weight average molecular weight is in the range of 140,000 to 180,000. In particular, when the softening point is less than 150 ° C., the lithographic printing ink film in the drier at the time of printing tends to be soft, the surface strength is weakened, and rubbing stains are likely to occur. When the weight average molecular weight exceeds 300,000, the solubility decreases, and the solvent releasability becomes faster, so that the on-machine stability is inferior and paper peeling tends to occur. Moreover, since it has high elasticity, it tends to cause a decrease in pigment dispersibility, a decrease in thickness on the paper surface, and a decrease in gloss due to a decrease in leveling and fluidity. The higher the softening point, the more the film strength can be imparted. However, the higher the softening point, the higher the molecular weight. In this specification, a weight average molecular weight is a measured value by GPC method (polystyrene conversion).

  Moreover, it is preferable that the acid value of the rosin modified phenolic resin of this invention exists in the range of 0-30 mgKOH / g. Of these, 16 mgKOH / g or less is particularly preferable. Although some resins cannot measure the acid value, in this specification, such a resin is considered to have an acid value of 0 mgKOH / g. When it exceeds 30 mgKOH / g, the drying property is lowered, which may cause rubbing stains or easily emulsify.

  The content of the rosin-modified phenolic resin of the present invention in the total amount of lithographic printing ink is preferably in the range of 20 to 35% by weight. If it is less than 20% by weight, the solid content is small, so that the viscosity becomes low and it becomes difficult to obtain a desired lithographic printing ink. If it exceeds 35% by weight, the gloss tends to decrease.

  In addition to the rosin-modified phenolic resin of the present invention, for the purpose of improving the production suitability, physical properties and printability of lithographic printing inks such as adjustment of viscosity and viscoelasticity, imparting cohesive force, and reduction of change over time, A rosin-modified phenol resin, a rosin ester resin, an alkyd resin, gilsonite, and the like can be appropriately selected and used. However, selecting a highly soluble resin is not preferable because of poor setability.

  The vegetable oil component used in the lithographic printing ink of the present invention is preferably soybean oil or a fatty acid ester derived from soybean oil. Examples of other vegetable oils include linseed oil, rapeseed oil, coconut oil, olive oil, tung oil, and the like, and those obtained by regenerating them. In addition, as other fatty acid esters derived from vegetable oils, for example, fatty acids derived from dry oil or semi-dry oil such as cottonseed oil, linseed oil, safflower oil, sunflower oil, tung oil, tall oil, dehydrated castor oil, rapeseed oil, sesame oil, etc. A monoalkyl ester can be illustrated. The alcohol-derived alkyl group constituting the fatty acid monoalkyl ester preferably has 5 to 12 carbon atoms, and specific examples include pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, and 3-methyl-1-butyl. 2,4-dimethyl-3-pentyl, 2-ethyl-1-hexyl, 3,5,5-trimethyl-1-hexyl, 4-decyl, 2-isopropyl-5-methyl-1-hexyl, 2-butyl -1-octyl and the like. Of these, 2-ethyl-1-hexyl, octyl and the like are particularly preferable. The vegetable oil component has an excellent effect of improving the gloss of printed matter because of increased solubility in the resin.

  The vegetable oil component is preferably in the range of 7 to 30% by weight in the total amount of the lithographic printing ink of the present invention. Of these, the range of 10 to 25% by weight is particularly preferable. If it is less than 7% by weight, the gloss is lowered. Even if an amount exceeding 30% by weight is added, the effect of improving the gloss is not obtained, the solubility becomes high, and the increase of the tack with time increases, so the adhesiveness of the ink deposited on the blanket increases, and the after-sales The tack remains, making it easier to remove the paper.

  The ratio of the fatty acid ester derived from soybean oil and soybean oil is preferably in the range of 100/0 to 30/70 by weight. Especially, it is especially within the range of 90 / 10-50 / 50. If the fatty acid ester derived from soybean oil exceeds 70% by weight in the ratio of soybean oil to soybean oil-derived fatty acid ester, the tack becomes high and the paper is easily peeled off.

  In the lithographic printing ink of the present invention, pigments, additives, solvents, and the like that are conventionally used in known lithographic printing inks can be used in addition to vinylidene olefins, rosin-modified phenolic resins, and vegetable oil components.

  Examples of the pigment include organic pigments and inorganic pigments, such as organic pigments typified by disazo yellow, carmine 6B, phthalocyanine blue, and inorganic pigments typified by carbon black, calcium carbonate, and the like, and are not particularly limited. .

  Examples of the additive include an aluminum chelating agent, a pigment dispersant, an emulsifier, an anti-drying agent, a drying accelerator, a surface conditioner, and a lubricant for the purpose of improving the printability, physical properties, and printability of the lithographic printing ink. There is no particular limitation.

  As the solvent, for the purpose of imparting fluidity, a petroleum solvent represented by AF solvent, normal paraffin solvent, isoparaffin solvent, machine oil, cylinder oil and the like can be appropriately selected and used. If the purpose is to remove components and the like, it is preferably not used.

  If the additive used for the lithographic printing ink of the present invention is selected so that it does not contain a VOC component, a lithographic printing ink substantially free of a VOC component can be obtained.

  The lithographic printing ink of the present invention is a lithographic printing having appropriate physical properties and printability, such as offset rotary printing ink, sheet-fed offset printing ink, waterless offset rotary printing ink, waterless sheet-fed offset printing ink, etc. A lithographic printing ink can be obtained according to various uses. Especially, it is preferable to prepare as offset rotary printing ink and waterless offset rotary printing ink.

  The substrate used for printing the lithographic ink of the present invention is not particularly limited as long as it has a shape provided for lithographic printing. For example, various papers suitable for lithographic printing, plastic films, plastic sheets, woven fabrics, non-woven fabrics, wood chip sheets and those having a surface made of those materials can be mentioned. Paper), finely coated paper, coated paper, and art paper. Appropriate paper is appropriately selected according to the density, surface condition, drying temperature of the dryer, printing speed, and the like. In particular, the lithographic printing ink of the present invention is excellent in paper peeling suitability and gloss, so that it can be applied to low-quality paper, for example, reprinted paper (non-coated paper), finely coated paper, lightweight coated paper, etc. A printed matter with high image quality can be obtained.

  The drying property depends on the drying temperature when performing heat-set type offset rotary printing. As the drying temperature is higher, the drying property is improved. However, when the gloss is lowered or the substrate is paper, a phenomenon such as back cracking or blistering of the printed matter is likely to occur due to a decrease in water content. Further, the surface strength is weakened due to the softening of the film, and rubbing dirt is likely to occur. The drying temperature refers to the hot air temperature of the dryer, which is approximately 150 to 220 ° C., and the paper surface temperature near the outlet of the dryer is approximately 85 to 130 ° C.

  In the lithographic printing ink of the present invention, since vinylidene olefin has a low viscosity, it has high penetrability, improved setability, and the softening point of rosin-modified phenolic resin is relatively high. Since the solubility is high and the on-machine stability is high, even if the drying temperature is lowered, problems due to poor drying hardly occur. For example, the hot air temperature can be lowered to 150 ° C. or lower, and the paper surface temperature can be set to 75 ° C. or lower.

  The lithographic printing ink of the present invention can be produced by a conventionally known method. For example, the rosin-modified phenol resin and / or other rosin-modified phenol resin of the present invention is mixed with a material arbitrarily selected from vegetable oil components, vinylidene olefins, aluminum chelating agents and the like, and mixed and heated to dissolve to obtain a varnish. The mixture is prepared with a vegetable oil component, vinylidene olefin, an additive, a solvent, and the like in a mixture in which a pigment is dispersed in this varnish with a three-roll, bead mill or the like.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, it is not limited only to a following example etc. In Examples and the like, “parts” and “%” represent “parts by weight” and “% by weight” unless otherwise specified.

[Preparation of varnish]
(Production Example 1)
Rosin modified phenolic resin A (weight average molecular weight 140,000, softening point 187 ° C., acid value 16 mgKOH / g) 20% by weight, rosin modified phenolic resin B (weight average molecular weight 170,000, softening point 185 ° C., acid value 19 mgKOH / g) 20 wt%, 2-octyl-1-dodecene 29.7 wt%, soybean oil 15 wt%, soybean oil fatty acid 2-ethyl-1-hexyl ester 15 wt%, aluminum chelating agent (ALCH, Kawaken Fine Chemical ( Co., Ltd.) 0.3 wt% was charged into a reaction vessel, heated to 185 ° C. while blowing nitrogen gas, and stirred and mixed for 60 minutes to obtain varnish V1.

(Production Example 2)
10% by weight of rosin-modified phenolic resin A, 30% by weight of rosin-modified phenolic resin B, 29.7% by weight of 2-octyl-1-dodecene, 15% by weight of soybean oil, 15% by weight of soybean oil fatty acid 2-ethyl-1-hexyl ester, An aluminum chelating agent (ALCH, manufactured by Kawaken Fine Chemical Co., Ltd.) of 0.3 wt% was charged into a reaction vessel, heated to 185 ° C. while blowing nitrogen gas, and stirred and mixed for 60 minutes to obtain varnish V2. It was.

(Production Example 3)
Rosin modified phenolic resin A 20% by weight, rosin modified phenolic resin B 20% by weight, 2-octyl-1-dodecene 29.7% by weight, soybean oil 30% by weight, aluminum chelating agent (ALCH, manufactured by Kawaken Fine Chemical Co., Ltd.) 0.3 wt% was charged in a reaction vessel, heated to 185 ° C. while blowing nitrogen gas, and stirred and mixed for 60 minutes to obtain varnish V3.

(Production Example 4)
Varnish V4 was obtained in the same manner as in Production Example 1 except that 2-octyl-1-dodecene was replaced with 2-dodecyl-1-hexadecene.

(Production Example 5)
20% by weight of rosin-modified phenolic resin A, 20% by weight of rosin-modified phenolic resin B, 41.7% by weight of 2-octyl-1-dodecene, 13% by weight of soybean oil, 5% by weight of soybean oil fatty acid 2-ethyl-1-hexyl ester, An aluminum chelating agent (ALCH, manufactured by Kawaken Fine Chemical Co., Ltd.) of 0.3 wt% was charged into a reaction vessel, heated to 185 ° C. while blowing nitrogen gas, and stirred and mixed for 60 minutes to obtain varnish V5. It was.

(Reference Production Example 1)
Varnish U1 was obtained in the same manner as in Production Example 1 except that 2-octyl-1-dodecene was replaced with a mixture of α-olefin 1-hexadecene and 1-octadecene (Dialen 168, manufactured by Mitsubishi Chemical Corporation). It was.

(Reference Production Example 2)
Rosin modified phenolic resin A 25% by weight, rosin modified phenolic resin C (weight average molecular weight 20,000, softening point 170 ° C., acid value 25 mgKOH / g) 5% by weight, rosin modified phenolic resin D (weight average molecular weight 70,000, softening) 160 ° C., acid value 23 mg KOH / g) 10% by weight, AF solvent 7 (manufactured by Nippon Oil Co., Ltd.) 28% by weight, soybean oil 10% by weight are charged into a reaction vessel, and nitrogen gas is blown into 190 ° C. The solution was stirred and dissolved for 30 minutes, and then AF Solvent 7 (manufactured by Shin Nippon Oil Co., Ltd.) 21.40% by weight was added, and an aluminum chelating agent (ALCH, manufactured by Kawaken Fine Chemical Co., Ltd.) 0. 6 wt% was charged and stirred at 170 ° C. for 45 minutes to obtain varnish U2.

[Preparation of lithographic printing ink]
Examples 1-5, Comparative Examples 1-2
Table 1 shows the ink component compositions in Examples and Comparative Examples.
Varnish and phthalocyanine blue (Fastgen Blue GBK-19SD, manufactured by DIC Corporation) were blended according to the formulation in Table 1, and kneaded with a three-roll mill to obtain an ink base. Further, varnish, 2-octyl-1- Add and mix dodecene, 2-dodecyl-1-hexadecene, a mixture of 1-hexadecene and 1-octadecene (Dialen 168, manufactured by Mitsubishi Chemical Corporation), or AF Solvent 7 (manufactured by Nippon Oil Corporation) The lithographic printing inks of Examples 1 to 5 and Comparative Examples 1 and 2 having a viscosity of 20 to 25 Pa · s were obtained.

  The following evaluation was performed about the ink for lithographic printing obtained in Examples 1-5 and Comparative Examples 1-2. The results are shown in Table 2.

[Drying]
The lithographic printing ink obtained in each Example and Comparative Example was used for lithographic printing under the conditions of a printing pressure of 400 N and a printing speed of 10 m / sec using a Prüfbau printing aptitude tester (MZ-II, manufactured by Prüfbau Co., Ltd.). The sample piece was dried by spreading 0.2 cc of ink on coated paper and adjusting the paper surface drying temperature to 75 ° C. The dried sample piece was immediately taken out and the stickiness of the sample piece was evaluated by finger touch. The dryness is better as there is no stickiness. The degree of stickiness was evaluated in three stages: ◯: no stickiness, Δ: somewhat sticky (no problem for practical use), ×: stickiness, not practical. The Prüfbau printing aptitude tester is a tester developed at the FOGRA printing plate making laboratory in Germany and widely used for evaluation of lithographic printing inks.

[Setability]
The ink for lithographic printing obtained in each example and comparative example was developed on coated paper and fine coated paper with an RI tester (manufactured by Akira Seisakusho), and immediately an automatic ink set tester (Toyo Seiki Co., Ltd.) The degree of adhesion of the lithographic printing ink to the high-quality paper superimposed on the color development surface was visually confirmed, and the time required until no adhesion was observed was measured. The shorter this time, the better the setability.

[Applicability to remove paper]
The tack value of the lithographic printing inks obtained in each of the Examples and Comparative Examples was measured using a digital incometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a roller temperature of 32 ° C. and a roller rotation number of 800 rpm. The smaller the measured value, the better the paper peeling ability. The tack value was evaluated in three stages: ○: 5.5 or less, Δ: greater than 5.5, 6.0 or less (no problem in practical use), and x: greater than 6.0.

[Glossy]
The lithographic printing ink obtained in each Example and Comparative Example was developed on coated paper with an RI tester (manufactured by Akira Seisakusho), left in a drier kept at 120 ° C. for 10 seconds, taken out, and a printed piece was removed. Obtained. Each printed piece was measured with a gloss meter (PG-1, manufactured by Nippon Denshoku Industries Co., Ltd.). The greater this measurement, the better the gloss. The gloss value was evaluated in three stages: ○: 55 or more, Δ: less than 55, 50 or more (no problem in practical use), and x: less than 50.

[Onboard stability]
The change in tack value with time was measured for the lithographic printing ink obtained in each Example and Comparative Example using a digital incometer (manufactured by Toyo Seiki Seisakusyo Co., Ltd.) at a roller surface temperature of 42 ° C. and a roller rotation speed of 1200 rpm. Over time, the solvent in the lithographic printing ink is released and the tack is increased. However, when the solvent to be removed is lost, the tackiness is lost and the tack starts to decrease. The smaller the slope of the straight line connecting the tack value at the start of measurement and the tack value at the start of dropping (tack increase width ΔT), the better the on-machine stability. The tack increase width ΔT was evaluated in three stages: ○: ΔT ≦ 1.0, Δ: 1.0 <ΔT ≦ 1.5 (no problem in practical use), and x: 1.5 <ΔT.

  As shown in Table 2, the lithographic printing inks of Examples 1 to 5 are excellent in setability, have paper peeling suitability, and have sufficient on-machine stability, so that they are offset at a low temperature without reducing the printing speed. Since rotary printing can be performed and gloss does not deteriorate, a printed matter with high image quality can be provided. The lithographic printing ink using the α-olefin of Comparative Example 1 is inferior in paper peeling suitability. The conventional lithographic printing ink of Comparative Example 2 has poor paper peelability, on-machine stability, and low gloss.

  The lithographic printing ink of the present invention can provide printed matter with high image quality even on low-quality paper, can reduce energy required for drying, and can be applied to provide environmentally-friendly printed matter that can remove VOC components. Furthermore, it is also useful as a waterless lithographic printing ink or a sheet-fed lithographic printing ink.

Claims (6)

A lithographic printing ink comprising a compound represented by the general formula (1), a rosin-modified phenolic resin, and a vegetable oil component.

(In the formula, R ¹ and R ² represent a linear alkyl group.) The lithographic printing according to claim 1, wherein in the compound represented by the general formula (1), R ¹ has 8 to 12 carbon atoms and R ² has 10 to 14 carbon atoms. Ink.   The softening point of the rosin-modified phenolic resin is in the range of 150 to 220 ° C, and the weight average molecular weight is in the range of 120,000 to 300,000. Ink for lithographic printing.   The lithographic printing ink according to any one of claims 1 to 3, wherein the vegetable oil component is soybean oil or a fatty acid ester derived from soybean oil.   The lithographic printing ink according to any one of claims 1 to 4, wherein the lithographic printing ink is an offset rotary printing ink.   The printed matter printed on the base material using the lithographic printing ink according to any one of claims 1 to 5.