JPH0345753B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a dry lithographic printing ink. Currently, common printing methods include letterpress printing, planographic printing, intaglio printing, etc. Among planographic printing, in wet offset printing, the printing plate surface consists of a hydrophilic part and a lipophilic part, and the ink is applied to the lipophilic part. This is a method that transfers the image only to the image and obtains a line image. This printing method is characterized by the fact that images are clear, high-quality printed matter can be obtained, plate making costs are low, and plate making can be done in a short time. However, since this printing method uses dampening water along with ink during printing, it is necessary to control the dampening water as well as the ink, and the printing operation requires a high level of skill. For this reason, I have not used dampening water recently.
A printing method that allows lithographic offset printing has been proposed. In other words, it is a dry lithographic printing method, and printing with this method eliminates the problems caused by dampening water that were problems with conventional wet offset printing, such as emulsification of printing ink, poor transfer due to water loss, and occurrence of ghosting. is improved. However, if printing is continued for a long time by this dry lithographic printing method using ordinary ink, the temperature on the plate surface will rise, and the ink will easily adhere to the non-image areas, causing stains. As a means to solve this problem, a method has been proposed in which various ink materials are modified with silicon compounds. For example, silicon-modified alkyd resin (Special Publication No. 51-10124, No. 51-22405)
No.), silicone-modified phenolic resin (Special Publication No. 1989-
10042, JP-A-52-62506), silicon-modified drying oil (JP-A-52-10041, JP-A-52-10042), silicone-modified cyclopentadiene resin (JP-A-52-10041, JP-A-52-10042)
-110705, 56-110706), etc. Although these materials are effective against stains, depending on the combination, the stain resistance may still be unsatisfactory, or when the background stain resistance is improved, the gloss of the printed matter deteriorates and the quality of the printed matter deteriorates. There are some drawbacks such as. On the other hand, the problem with ink is that the ink thickens during storage, resulting in poor workability. Furthermore, compared to general ink materials, siloxane compounds are
Since it is very expensive, it has disadvantages such as increasing the price of ink. The present inventors have repeatedly researched the relationship between the ink and the plate for ink compositions that are compatible with the above-mentioned dry lithographic printing method, and have found that the ink composition has excellent printability and storage stability that can be used practically in the dry lithographic printing method. In addition, we have achieved the invention of a dry lithographic printing ink that can produce printed matter with good printing effects. general formula (In the formula, H represents a hydrogen atom, R represents an alkyl group having 1 to 3 carbon atoms, m and n are integers of 0 or 1 or more, and m+n = 6.) 100 parts by weight of a 5-membered ring compound and/or a Diels-Alder adduct of the 5-membered ring compound [A], and at least one member selected from the group consisting of a drying oil and a fatty acid [B] 5
100 parts by weight of a hydrocarbon resin [] obtained by copolymerizing ~50 parts by weight with an acid-modified resin [] made by reacting 1 to 15 parts by weight of an unsaturated carboxylic acid or its anhydride [C]. , by heating and reacting 5 to 100 parts by weight of a phenol resin [D] obtained by condensation of a phenol having an alkyl substituent having 4 to 9 carbon atoms with formalin, to 100 parts by weight of the acid-modified resin []. The present invention relates to a dry lithographic printing ink containing the obtained resin [ ] as a vehicle component. The present invention will be described in further detail below. In the present invention, a five-membered ring compound having a conjugated double bond represented by the following general formula and/or its Diels-Alder adduct is used as the raw material component [A]. formula: (Here, R represents an alkyl group having 1 to 3 carbon atoms, H represents a hydrogen atom, m and n are integers of 0 or 1 or more, and m+n = 6.) Specifically, as a 5-membered ring compound. , cyclopentadiene and methylcyclopentadiene, and their Diels-Alder adducts such as dicyclopentadiene, cyclopentadiene-methylcyclopentadiene codimer, tricyclopentadiene, and mixtures thereof are industrially preferred. Of these, cyclopentadiene, dicyclopentadiene or mixtures thereof are particularly preferred. Although it is not necessary that [A] be of high purity, it is preferable that cyclopentadiene, dicyclopentadiene, or their alkyl-substituted derivatives be present in an amount of 80% by weight or more. For example, by thermally dimerizing cyclopentadiene and methylcyclopentadiene contained in the _C5 fraction of high-temperature pyrolysis byproduct oil such as naphtha, dicyclopentadiene, dimethylcyclopentadiene, cyclopentadiene-methylcyclopentadiene, etc. After forming a mixture of codimer, cyclopentadiene-isoprene codimer, cyclopentadiene-piperylene codimer, etc., most of the _C5 components such as _C5 olefin and _C5 paraffin are removed by distillation. The resulting concentrated fraction may be used. [B] used in the present invention is at least one component selected from the group consisting of drying oils and fatty acids. Drying oils include vegetable oils and animal fats with an iodine value of 120 or more, with drying vegetable oils such as linseed oil, tung oil, soybean oil, and dehydrated castor oil being particularly preferred. Moreover, boiled oil obtained by heat-treating these can also be used. Fatty acids include saturated or unsaturated synthetic fatty acids such as myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linoleic acid and eleostearic acid, and natural fatty acids such as linseed oil fatty acid and tall oil fatty acid. It is.
Furthermore, tall oil containing fatty acids as a main component can also be used as the fatty acid. Furthermore, there is no particular problem in using a mixture of two or more of the above components as [B]. In the present invention, hydrocarbon resin [I] is produced by thermally reacting 100 parts by weight of [A] with 5 to 50 parts by weight, preferably 10 to 40 parts by weight, of [B] without a catalyst. . Hydrocarbon resin [I] can be produced by heating the mixture of [A] and [B] above at 200 to 300°C for 30 minutes to 15 hours, preferably 1 to 7 hours. If the amount of [B] is less than the above range, sufficient effect will not be observed,
On the other hand, if it exceeds the above range, the softening point of the resin will decrease, which is not preferable. In addition, in order to obtain excellent solubility of the binder resin in paraffinic solvents, in addition to the above [A] and [B], α-
Olefin, preferably having 6 to 20 carbon atoms, α
- A linear and/or branched α-olefin that does not have an alkyl group at the β-position of the olefin,
[A] By adding 5 to 100 parts by weight, preferably 10 to 50 parts by weight, to 100 parts by weight, it becomes possible to produce a binder resin that satisfies the above requirements. The final resin produced by modifying the resin obtained by the thermal reaction of [A], [B] and the above α-olefin has extremely good solubility in paraffinic solvents, and the printing suitability of ink using this resin is extremely good. will also improve further. Commercially available pure monomers can be used as α-olefins, but single monomers or mixed monomers obtained by (1) so-called ethylene oligomerization or (2) thermal decomposition of paraffin wax can be used. You can also. Hydrocarbon resin [I] obtained as described above
is reacted with an unsaturated carboxylic acid or its anhydride [C], and [C] is usually a monomer having 3 to 32 carbon atoms, preferably 3 to 15 carbon atoms, and a polyunsaturated carboxylic acid or anhydride thereof. Typical of these are acrylic acid, methacrylic acid, maleic acid, maleic anhydride, tetrahydrophthalic acid and its anhydrides, fumaric acid, citraconic acid, itaconic acid and mixtures thereof or drying oil fatty acids, e.g. These include linseed oil fatty acids. Among these, maleic acid and maleic anhydride are preferred. The amount ratio of the unsaturated carboxylic acid or its anhydride used in the present invention is 1 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the hydrocarbon resin [I]. When the amount of unsaturated carboxylic acid or its anhydride is less than the above range, the amount of polar groups in the resulting resin is small, so the characteristics as a resin having polar groups are poor, and it cannot be used as a vehicle for ink. In this case, pigment dispersibility, ink fluidity, and printing effect deteriorate, which is undesirable. Moreover, if it exceeds the above range, the amount of polar groups is too large, solubility in solvents becomes poor, and discoloration and gelation of the resin tend to occur, which is not preferable.
Furthermore, when used in ink, the solubility in hydrocarbon solvents during varnishing becomes poor, and the fluidity of the ink and the gloss of printed matter become poor, which is undesirable. In addition, the above acid denaturation reaction is carried out at 100 to 300℃.
Preferably at a temperature within the range of 150 to 250°C, without a catalyst or in the presence of a known radical initiator, such as an organic peroxide, for 30 minutes to 15 hours, preferably 1 to 8 hours.
When using an unsaturated polycarboxylic acid or its anhydride, it can be carried out without a catalyst, and when using an unsaturated monocarboxylic acid or its anhydride, it can be carried out in the presence of a catalyst. , it is preferable to carry out the reaction. The acid-modified resin of the present invention [ ] can also be produced by the following general method. That is, when thermally polymerizing a mixture of [A] and [B] at a temperature of 200 to 300°C in the presence or absence of a solvent, an unsaturated carboxylic acid or its anhydride is added to the reaction system from the beginning or during the reaction. It can also be obtained by thermal polymerization. In addition, in the present invention, in order to adjust the solubility and softening point of the acid-modified resin [] obtained above, or to adjust the molecular weight of the resin [], the acid-modified resin [] has a carbon number of 6 or more. Esterification with preferably 8 to 22, particularly preferably 12 to 15, higher monohydric alcohols is also possible. The amount of alcohol used at that time is 0 per molar equivalent of carboxyl group in the acid-modified resin [].
~0.1 molar equivalent, or 0 to 2.0 molar equivalent per molar equivalent of acid anhydride group in the resin [].
The esterification reaction is carried out by heating and melting the acid-modified resin or by adding a monohydric alcohol to the solution in a hydrocarbon solvent such as benzene, toluene, or xylene, and then heating the resin at a temperature of 150 to 250°C for 30 minutes to 10 minutes. The reaction time is preferably 1 to 5 hours. In the present invention, the desired resin [] is obtained by further reacting the acid-modified resin [] with the alkyl-substituted phenolic resin [D]. The phenolic resin used in the present invention is obtained by condensing a phenol having an alkyl substituent having 4 to 9 carbon atoms with formalin, and the phenol mentioned here specifically includes p-tert-butylphenol, sec-butylphenol, p-tert-octylphenol, and nonylphenol are preferably used industrially, and unsubstituted phenol or phenolic resin such as cresol reduces the solubility of the resulting resin in high-boiling hydrocarbons. This is not desirable because it causes Further, if a substituted phenol resin having 10 or more carbon atoms is used, the softening point of the resin [] will be significantly lowered, which is not preferable. Alternatively, instead of reacting with a phenolic resin, formaldehyde and phenols may be reacted in the presence of an acid-modified resin with an acid or alkali as a catalyst or without a catalyst to obtain the desired phenolic resin-modified resin. I can do it. The amount of phenolic resin used for modification is in the range of 5 to 100 parts by weight, more preferably 10 to 50 parts by weight, per 100 parts by weight of the acid-modified resin. If the amount of phenolic resin is less than the above range, when an ink is prepared using the obtained modified resin vehicle, the fluidity of the ink and the gloss of the printed matter will be insufficient, and if the amount exceeds the above range, the ink solvent of the resin will be insufficient. Not only does this result in poor solubility, but it is also industrially uneconomical and undesirable. For the reaction, it is sufficient to mix and melt the acid-modified resin [] and the phenolic resin and heat the mixture at 150 to 250°C for 30 minutes to 10 hours, preferably 1 to 5 hours, but if necessary, an acid catalyst such as sulfuric acid may be used. , toluenesulfonic acid, Friedel-Crafts type catalysts, etc. can also be used. The resin [] obtained as described above preferably has a softening point of 100°C or higher, particularly 130°C or higher. If the softening point is lower than 100°C, when used as a printing ink, there will be a lot of misting, the drying speed will be extremely low, and blocking will easily occur, which is undesirable. Furthermore, if the softening point is lower than 100° C., the scumming resistance in dry lithographic printing will not be satisfactory. Furthermore, the resin [] has an acid value of 5 to 70, especially 5 to 70.
A range of 50 is preferred. If the acid value is less than the above range, the pigment dispersibility will be poor, and if the acid value exceeds the above range, the solubility in paraffin solvents will decrease, resulting in deterioration of the fluidity of the ink, or the ink may deteriorate during storage. becomes thicker. The resin made in this way [] has less thickening of the ink during storage, and the gloss of printed matter is good.
It is possible to obtain an ink for dry lithographic printing that satisfies both resistance to background smearing during printing by dry lithography. The method for preparing the dry lithographic printing ink of the present invention using the thus obtained resin [ ] as a vehicle component can be carried out according to any commonly known method. In the lithographic printing ink, 100 parts by weight of the resin obtained as described above is mixed with 5 to 150 parts by weight, preferably 10 to 100 parts by weight, of a medium oil length and/or long oil length alkyd resin.
parts by weight, dissolved in 50 to 200 parts by weight of a high boiling point hydrocarbon solvent at room temperature or under heating to reduce the viscosity at room temperature to 200 parts by weight.
It is obtained by blending varnish adjusted to ~600 poise with a face balance and kneading it. Drying oils or polymeric drying oils may also be used in place of or in addition to the alkyd resin. Furthermore, if necessary, the varnish (vehicle) can be prepared by heating it at 200 to 260°C to obtain the desired solubility. As the drying oil used in ink production, the drying oil used in the synthesis of resin can be similarly used, but for example, vegetable crude oil such as tung oil, linseed oil, soybean oil, oiticica oil, etc. Boil oil, No. 0 oil, No. 1 oil, No. 3 oil, No. 4 oil, No. 5 oil,
These include polymerized linseed oil such as No. 6 oil, No. 7 oil, No. 9 oil, and extra-sized varnish, and or similarly polymerized vegetable oils such as polymerized tung oil. Furthermore, medium-oil length and long-oil length alkyd resins include linoleic acid, linolenic acid, oleic acid,
One or a mixture of unsaturated fatty acids such as licanoic acid, eleostearic acid, and ricinolenic acid, stearic acid, palmitic acid, lauric acid, and capric acid, as well as glycerides and tall oil of these fatty acids. and glycols such as ethylene glycol, diethylene glycol and neopentyl glycol, polyols such as glycerin, trimethylolethane, trimethylolpropane, trishydroxyethyl isocyanurate, pentaerythritol, diglycerin, dipentaerythritol and tripentaerythritol, and anhydrous. It consists of at least one component from each group, such as phthalic acid, isophthalic acid, trimellitic acid, adipic acid, terephthalic acid, (anhydrous) maleic acid, (anhydrous) fumaric acid, etc., and has an oil length of 50% to 90%. It is an alkyd resin. The high-boiling hydrocarbon solvent used in the present invention has a boiling point range of 200 to 300°C, preferably 250 to 330°C, and an aromatic component content of 50% by weight or less, preferably 30% by weight or less. Furthermore, in the dry lithographic printing ink of the present invention, if scumming resistance is particularly required, organopolysiloxane may be added in an amount of 0.1 part by weight and 1 to 10 parts by weight. Adding organopolysiloxane in an amount exceeding the upper limit of this range is not preferable because it has disadvantages such as deterioration of ink fluidity, thickening during ink storage, and deterioration of gloss. Additionally, additives commonly used in dry lithographic printing inks can also be used. The present invention will be explained below with reference to Examples. Synthesis example 1 Dicyclopentadiene (DCPD) with purity of 97%
850 g and 250 g of linseed oil were placed in autoclave No. 2, and heated at 260° C. for 3.5 hours under stirring in a nitrogen atmosphere. After the heating was completed, the autoclave was cooled and the contents were distilled at 210° C./2 mmHg to obtain 920 g of resin (-1). The softening point of resin (-1) is
It was 136.5℃. 150 g of this resin (-1) was heated and melted at 200°C, 4.5 g of maleic anhydride was added, and the reaction was carried out for 4 hours with stirring to obtain an acid-modified resin (-1). (
-1) had a softening point of 147.0°C and an acid value of 13.5.
Subsequently, add p- to 100 g of acid-modified resin (-1)
Resol type phenolic resin obtained by condensation reaction of tert-octylphenol and formalin
Add 17.6g and react at 200℃ for 2 hours to determine the softening point.
Resin (-1) was obtained at 169.5°C and with an acid value of 12.7. Synthesis example 2 800g of DCPD with a purity of 97% and 200g of tall oil
The mixture was charged into an autoclave, reacted at 260°C for 6 hours, and treated in the same manner as in Synthesis Example 1 to obtain 925 g of resin (-2). The softening point of (-2) is
The temperature was 138.5℃. 150 g of this resin (-2) was heated and melted at 200°C, 7.5 g of maleic anhydride was added, and the reaction was carried out for 3 hours with stirring to obtain an acid-modified resin (-2). (
-2) had a softening point of 158.0°C and an acid value of 24.2.
Subsequently, 4.2 g of decanol was added to 100 g of acid-modified resin (-2) and heated and stirred at 200°C for 1 hour, followed by a resol type phenol resin obtained by a condensation reaction between p-nonylphenol and formalin.
20.2g was added and reacted at 200°C for 3 hours to obtain a resin (-2) with a softening point of 160.5°C and an acid value of 19.4. Synthesis Example 3 800g of DCPD with a purity of 97%, 100g of linseed oil, and 100g of 1-hexene were placed in the autoclave No. 2, and reacted at 280°C for 2 hours, and treated in the same manner as Synthesis Example 1 to produce 932g of resin (-3). Obtained. (
-3) had a softening point of 146.0°C. 150 g of this resin (-3) was heated and melted at 200°C, 4.5 g of maleic anhydride was added, and the reaction was carried out for 3 hours with stirring to obtain an acid-modified resin (-3). The softening point of acid-modified resin (-3) is 155.0℃ and the acid value is
It was 13.7. Subsequently, acid modified resin (-3)
To 100 g, 17.6 g of resol type phenolic resin obtained by condensation reaction of p-tert-octylphenol and formalin was added and reacted at 200°C for 2 hours to obtain a resin (-3) with a softening point of 175.0°C and an acid value of 12.2.
I got it. Varnish preparation example 1 300 g of resin [-1], 100 g of No. 9 linseed oil, and 260 g of Nippon Oil No. 3 solvent were placed in a four-necked flask with a stirrer, and heated while blowing _N2 gas to raise the temperature to 150°C. While stirring, further raise the temperature to 180℃ and keep it warm for 30 minutes, then add No. 3 solvent.
28 g were added to obtain Varnish I with a viscosity of 540 poise at 25°C. 1,480 g of this varnish was placed in a four-necked flask with a stirrer, stirred and heated while blowing _N2 gas, and heated to 140°C using ALCH (manufactured by Kawaken Fine Chemicals).
Gelling agent; diisopropyl monoacetylacetoaluminum) 5g was added to Nippon Oil No. 5 Solvent 15.
A gelling agent solution mixed with g was added thereto, and the temperature was further raised to 190°C and stirred for 1 hour to obtain a gel varnish. Varnish preparation example 2 305 g of resin [-2], 100 g of Chinese tung oil, 200 g of Nippon Oil No. 5 solvent, and 80 g of Nippon Oil No. 0 solvent were placed in a four-necked flask with a stirrer, heated while blowing N ₂ gas, The mixture was stirred at 150°C, further raised to 180°C, kept at the temperature for 30 minutes, and 20g of No. 0 solvent was added to obtain a varnish whose viscosity at 25°C was adjusted to 480 poise. Pour 480g of varnish into a four-necked flask with a stirrer, stir and heat while blowing _N2 gas.
At 140℃, add a gelling agent solution containing 5g of ALCH dissolved in 15g of No. 0 solvent, and further raise the temperature.
The mixture was heated to 190°C and stirred for 1 hour to obtain a gel varnish. Varnish preparation example 3 Put 380g of resin [-3], 140g of Arachide 5001 (Arakawa Chemical long oil long alkyd resin), and 150g of No. 0 solvent made by Nippon Oil into a four-necked flask with a stirrer, and while blowing _N2 gas. Heat,
The mixture was stirred at 150°C, further raised to 180°C, kept at the temperature for 30 minutes, and 40g of No. 0 solvent was added to obtain a varnish whose viscosity at 25°C was adjusted to 420 poise. Pour 210g of varnish into a four-necked flask with a stirrer, stir and heat while blowing _N2 gas.
Maintain the temperature at 90℃, add 20g of a gelling agent solution made by thoroughly mixing 3g of Octope Aluminum (gelling agent manufactured by Hope Pharmaceutical) with 17g of No. 0 solvent, heat and raise the temperature.
When the temperature reached 165°C, fluidity of the gel varnish was observed, so it was pumped out to obtain gel varnish-1. Furthermore, 215 g of varnish was placed in a four-necked flask with a stirrer, and stirred while blowing in _N2 gas.
The mixture was heated to 140°C, and 8g of a gelling agent solution prepared by dissolving 2g of ALCH in 6g of No. 0 solvent was added thereto, and the temperature was further raised to 190°C and stirred for 1 hour to obtain gel varnish-2. Varnish preparation example 4 320 g of resin [-3] and 150 g of Arachide 6700 (Arakawa Chemical's medium-length alkyd resin) were placed in a 4-necked flask with a stirrer, heated while blowing _N2 gas, and the mixture was heated to 150°C and stirring started. Then, continue to raise the temperature to 240℃, heat for 3 hours at the same temperature, add 167g of No. 3 solvent, and heat to 250℃.
A varnish with a viscosity of 568 poise at °C was obtained. 290g of varnish, 2.5g of ALCH and No. 3 solvent
A gel varnish was obtained using 7.5 g in the same manner as in Varnish Preparation Example 1. Comparative varnish adjustment example 1 Tamanol 358 (Arakawa Chemical rosin phenol resin) 250g, boiled oil 120g and No. 3 solvent 240
A comparative varnish was obtained in the same manner as in Varnish Preparation Example 1. still,
The viscosity of this varnish at 25°C was 600 poise.
Furthermore, a comparative gel varnish was obtained in the same manner as in Varnish Preparation Example 1 using 1380 g of comparative varnish, 4 g of ALCH, and 12 g of No. 3 solvent. Comparative varnish adjustment example 2 Nisseki Neopolymer 150 (Nippon Oil petroleum resin)
A comparative varnish was obtained in the same manner as in Varnish Preparation Example 1 using 300 g of linseed oil, 100 g of linseed oil, and 198 g of No. 3 solvent (viscosity at 25°C: 452 poise). 330 g of comparative varnish was placed in a four-necked flask with a stirrer, and a gelling agent solution prepared by thoroughly mixing 8 g of octope aluminum with 64 g of No. 3 solvent was added.
The temperature was raised while blowing N ₂ gas, and when the gel varnish began to show fluidity at 168°C, it was pumped out to obtain a comparison gel varnish. Preparation of ink Ink was prepared by kneading the following blending ratio (weight ratio) using three rolls.

【table】

【table】

【table】

[Table] These inks were evaluated. In other words, a dry lithographic printing plate with a non-adhesive layer made of silicone rubber was attached to a printing machine that had been modified to increase the temperature of the plate surface by installing an electric heater on the plate cylinder.
Printing was carried out while increasing the plate surface temperature without supplying dampening water, and the plate surface temperature was measured when scumming occurred on the printed matter at a constant solid density. The results are shown in the table below.

【table】

【table】

【table】

【table】

Claims (1)

[Claims] 1. General formula (In the formula, H represents a hydrogen atom, R represents an alkyl group having 1 to 3 carbon atoms, m and n are integers of 0 or 1 or more, and m+n = 6.) 100 parts by weight of a 5-membered ring compound and/or a Diels-Alder adduct of the 5-membered ring compound [A], and at least one member selected from the group consisting of a drying oil and a fatty acid [B] 5
100 parts by weight of a hydrocarbon resin [] obtained by copolymerizing ~50 parts by weight with an acid-modified resin [] made by reacting 1 to 15 parts by weight of an unsaturated carboxylic acid or its anhydride [C]. , by heating and reacting 5 to 100 parts by weight of a phenol resin [D] obtained by condensation of a phenol having an alkyl substituent having 4 to 9 carbon atoms with formalin, to 100 parts by weight of the acid-modified resin []. An ink for dry planographic printing characterized by containing the obtained resin [ ] as a varnish component. 2 Resin [] 100 parts by weight, medium oil length and/or long oil length alkyd resin 5 to 150 parts by weight, aromatic compound content 50% by weight or less, and boiling point range
The dry lithographic printing ink according to claim 1, which contains a varnish consisting of 50 to 200 parts by weight of a hydrocarbon solvent having a temperature of 200 to 350°C. 3 Resin [] 100 parts by weight, drying oil or polymerized drying oil 5 to 150 parts by weight, and aromatic compound content 50 parts by weight
The dry lithographic printing ink according to claim 1, which contains a varnish consisting of 50 to 200 parts by weight of a hydrocarbon solvent having a boiling point range of 200 to 350°C. 4 Resin [] 100 parts by weight, medium oil length and/or long oil length alkyd resin 5 to 150 parts by weight, aromatic compound content 50% by weight or less, and boiling point range 200 to 200 parts by weight.
The printing ink for dry lithography according to claim 2, which contains a varnish consisting of 50 to 200 parts by weight of a hydrocarbon solvent having a temperature of 350°C and 0.1 to 10 parts by weight of an organopolysiloxane. 5 100 parts by weight of resin [], 50 to 150 parts by weight of drying oil and/or polymerized drying oil, 50 to 200 parts by weight of a hydrocarbon solvent having an aromatic content of 50% by weight or less and a boiling point range of 200 to 350°C, and organohydrogen The dry lithographic printing ink according to claim 3, which contains a varnish containing 0.1 to 10 parts by weight of polysiloxane.