JP4419256B2 - Lithographic printing ink - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lithographic printing ink (hereinafter abbreviated as ink) used for printed matter such as magazines, books, posters, etc., and particularly relates to an ink containing soybean oil as a drying oil. The present invention relates to an ink for obtaining a printed matter having good printability and high quality such as gloss, halftone dot fillability and halftone dot reproducibility.
[0002]
[Prior art]
In recent years, inks using vegetable oils, especially soybean oils, have been used for the environment. In particular, in the United States, some laws regarding government publications stipulate that ink using soybean oil be used. However, in Japan, the cost of soybean oil is higher than that of conventional petroleum-based solvents, so that there are still obstacles to the spread of soybean oil ink.
[0003]
In general, soybean oil ink means an ink that can be approved by the American Soybean Association (ASA) and can be attached with an SOY seal, and is larger than the content specified by ASA. Soybean oil must be contained, and it is generally necessary to replace part of the petroleum solvent with soybean oil. Since the content of vegetable oil is higher than that of normal ink, The emulsification of the resin tends to be promoted and sometimes causes problems such as soiling.
[0004]
In recent years, in the printing industry, demands for labor saving, labor saving, automation, and high-speed printing have been increasing. Ink for printing is desired, and ink manufacturers have made various improvements.
[0005]
In particular, off-wheel printing has a printing speed several times faster than that of sheet-fed printing, and sometimes ink and fountain solution are severely emulsified on the rollers of the printing press and the printability is impaired. Occasionally occurred. Major problems in printability include ground stains due to ink adhering to the non-image area of the plate, ink accumulation on the blanket, ink accumulation on the roller, ink scattering from the roller, etc. In some cases, the efficiency of the printing work was significantly deteriorated.
[0006]
In addition, printability problems have an effect on the quality of printed matter, and there are problems such as insufficient solid fillability, uneven dot shape, missing dots, thick dots, insufficient gloss, etc. It was easy to occur.
[0007]
To cope with these problems, the cohesive force is increased by increasing the viscoelasticity of the ink to prevent the ink from diffusing into the non-image area of the printing plate. Improvements have been made such as suppression, improvement of dispersibility of the pigment and improvement of fluidity, and the like, but they have not completely solved the problem.
[0008]
[Problems to be solved by the invention]
The present invention has been made in order to solve such problems in the prior art, and the object is to reduce the cost of ink using soybean oil and to reduce the cost of printing for a long time. It is an object of the present invention to provide an ink that is free from smudges and that can produce a good printed matter without causing problems related to emulsification with fountain solution.
[0009]
[Means for Solving the Problems]
The present invention relates to an ink comprising a pigment, a resin, a drying oil and a solvent, wherein the drying oil is a soybean crude oil having an acid value of 0.5 or more or a polymer oil thereof, and the solvent is a paraffinic solvent and / or a naphthenic solvent. It is related with the ink characterized by being.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The soybean oil conventionally used for soybean oil ink is usually soybean white oil which is a grade as an edible oil that can be used for tempura and the like. The manufacturing process of soybean white oil is as follows. That is, the crude oil obtained by extracting and extracting soybeans is subjected to a degumming step to remove lecithin to obtain soybean degummed oil. This is followed by a deoxidation step for removing free fatty acids to produce soybean deoxidized oil, which is decolorized and deodorized to obtain soybean white squeezed oil. When salad oil is used, it is dewaxed to remove components that harden at low temperatures. In the decolorization step, not only the pigment but also trace metals, residual soap and the like are removed. In the deodorizing step, not only odorous components but also volatile components such as free fatty acids and unsaponified products are removed.
[0011]
The soybean crude oil used in the present invention means the above-mentioned soybean degummed oil, which is obtained only by removing lecithin and has no acid value of 0.5 or more because free fatty acids are not removed. In the present invention, the acid value is preferably 0.5 to 3.0. Moreover, since neither decolorization nor deodorization is performed, the color is a little darker than that of soybean white oil, and a lot of soybean odor is felt.
[0012]
In the present invention, the soybean crude oil can be used without any problem even if it is a heat-polymerized oil. In order to obtain a heat-polymerized oil, heat polymerization is performed at a temperature of 275 to 340 ° C., preferably 325 to 335 ° C. in an inert gas such as nitrogen gas for 1 to several hours until the desired viscosity is obtained. Good.
[0013]
The solvent that can be used in the present invention is a petroleum solvent having an aromatic component content of 1% by weight or less, and the main component is a paraffinic solvent and / or a naphthenic solvent, which is an ester solvent. In addition, alcoholic solvents and the like may be included.
[0014]
Ink in the present invention, Pigments, 10-50 weight% resin, and is from soybean oil 40 wt% and a solvent 1 to 40% by weight. The main types of ink are sheet-fed printing press inks and offset rotary printing press inks, but are not limited thereto. The soybean crude oil content is 20% for sheet-fed printing press inks. It is preferable that it is 7% by weight or more as an ink for a rotary offset printing press because it satisfies the conditions for ASA soybean oil ink.
[0015]
Organic pigments are often used as pigments, and disazo yellow, brilliant carmine 6B, and phthalocyanine blue are representative, and carbon black for black ink and other inorganic pigments are also used.
[0016]
Examples of the resin component used in the ink of the present invention include general rosin-modified phenol resins, petroleum resins, alkyd resins, ester gums, and rosin alkyds. Of these, rosin-modified phenolic resins synthesized from rosin, alkylphenols, formaldehyde, and polyols are particularly preferable. Those using paranonylphenol (PNP) and paradodecylphenol (PDDP) as the alkylphenol component, or PNP and / or PDDP and paraoctylphenol ( A material mainly composed of a rosin-modified phenol resin combined with POP) is effective.
[0017]
As a method for producing a rosin-modified phenolic resin, for example, after reacting 100 to 100 parts by weight of rosin with 40 to 130 parts by weight of a resole-type phenolic resin at 100 to 250 ° C., A polyol prepared by adding a polyol so that the hydroxyl group is 0.5 to 1.2 equivalent and esterified at 250 to 260 ° C., or a rosin esterified with a polyol and then reacting with a resol type phenol resin. There are manufactured ones, and all commonly known ones can be used.
[0018]
Petroleum resins can also be suitably used, and any of aromatic petroleum resins and DCPD (dicyclopentadiene) petroleum resins can be used. Aromatic petroleum resins are resins obtained by cationically polymerizing these monomers with coumarone, indene, vinyltoluene and the like as the main components, and can be modified with phenol or maleic acid, and have a weight average molecular weight of about 1000 to 6000. Is common.
[0019]
Examples of DCPD petroleum resins include those obtained by polymerizing cyclopentadiene, copolymerizing with other polar monomers such as phenol, maleic acid, drying oil, etc., and esterifying with polyol. There are about 10,000 to 200,000.
[0020]
Furthermore, the ink of the present invention may contain an aliphatic diol. By adding an aliphatic diol, it is possible to improve the solubility of the resin and adjust the viscoelastic properties such as tack, flow, viscosity, and elastic modulus as an ink to an optimum state. The content of the diol according to the present invention is suitably 0.1 to 5% by weight, preferably 0.2 to 4% by weight, more preferably 0.3 to 2% by weight, most preferred. The content is in the range of 0.4 to 1% by weight. When the content is less than 0.1% by weight, the intended effect cannot be obtained. On the other hand, when the content exceeds 5% by weight, the flow as a lithographic printing ink becomes too long and the viscosity becomes low. This is not preferable because problems such as misting, background contamination, and dot thickening are likely to occur.
[0021]
The aliphatic diol according to the present invention is preferably represented by the following general formula.
(A): HO (CH ₂ ) _h OH
(B): CH ₃ (CH ₂ ) _j C (CH ₂ OH) ₂ (CH ₂ ) _k CH ₃
(C): CH ₃ (CH ₂ ) ₁ C (OH) HC (R) H (CH ₂ ) _m OH
_{(D): HOCH 2 CH (} R) (CH 2) n CH (R) CH 2 OH
(In the formula, h is an integer of 2 to 7, j, k, l, m, and n are each independently an integer of 0 to 3, and R represents a methyl group or an ethyl group.)
[0022]
As the diol according to the present invention, 1,2-ethanediol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1, 7-heptanediol, etc., while branched structures include 2,2 dimethyl 1,3 propane diol, 2,2 diethyl 1,3 propane diol, 2 butyl 2 ethyl 1,3 propane diol, 2 ethyl 1, 3 hexane diol, 2 ethyl 1,3 pentane diol, 2 methyl 1,3 hexane diol, 2 methyl 1,3 heptane diol, 2,4 diethyl 1,5 pentane diol, 2,5 dimethyl 1,6 hexane diol, etc. a diol, particularly preferably, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl 1,3 propanedioic 2 butyl 2 ethyl 1,3 propane diol, 2 ethyl 1,3 pentane diol, 2 methyl 1,3 hexane diol, 2 methyl 1,3 heptane diol, 2,4 diethyl 1,5 pentane diol, 2,5 Dimethyl 1,6-hexanediol. These diols can be used alone or in combination of two or more as required.
[0023]
Among these diols, particularly preferred are diols having a branched chain structure rather than a linear structure in terms of molecular structure, and such diol has good compatibility with the resin and can improve the fluidity of the ink. it can. In addition, the presence of a branched alkyl group is preferable because the molecule is hydrophobic and has high hydrolysis resistance and excellent stability and stability.
[0024]
In addition, the diol according to the present invention may be used in combination with higher alcohols such as tridecanol, 2 hexyl octanol, 2 hexyl decanol, 2 octyl decanol, etc. to adjust the fluidity of the ink.
[0025]
In addition, as a method of blending the diol according to the present invention into the ink, it may be blended with the solvent in the varnish, or may be blended during the ink production, and can be appropriately selected.
[0026]
【Example】
Next, the present invention will be specifically described in detail. In the following, “part” means “part by weight” and “%” means “% by weight”.
[0027]
(Phenolic resin production example 1)
A mixture of 1030 parts of paranonylphenol, 290 parts of paraformaldehyde, and 800 parts of xylene is heated and dissolved in a four-necked flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, and then 80 parts of a 48% sodium hydroxide aqueous solution is added. And allowed to react at 70-80 ° C. for 5 hours. After the reaction, 125 parts of 6N hydrochloric acid and 200 parts of tap water are added, and the mixture is left to stir. The supernatant layer is taken out and washed with water to obtain about 2100 parts of a xylene solution of a resol type phenol resin having a nonvolatile content of 62%. It was.
[0028]
(Rosin modified phenolic resin production example 1)
A four-necked flask equipped with a stirrer, a Liebig condenser, and a thermometer was charged with 600 parts of gum rosin, heated and dissolved at 200 ° C. while blowing nitrogen gas, and 890 parts of A resole solution was reacted at 120-230 ° C., and then glycerin. 67 parts was charged and esterified at 250 to 260 ° C. until the acid value was 25 or less, to obtain a rosin-modified phenolic resin 1 having a molecular weight of 107,000, a cloudiness point of 40% and a resin viscosity of 150 poise.
[0029]
The cloud point is calculated by the following formula.
Cloud point (%) = resin / {resin + solvent (Xg)} × 100
However, X is the minimum amount of normal tetradecane in which the solution becomes cloudy when cooled to 25 ° C. after adding normal tetradecane to 2 g of resin and heating and dissolving at 180 to 200 ° C.
The resin viscosity is a viscosity at 25 ° C. of a varnish obtained by heating and dissolving a mixture having a weight ratio of resin / linseed oil = 1/2 at 180 to 200 ° C. while stirring.
[0030]
(Varnish production example 1)
Rosin-modified phenolic resin 1 44.0%, soybean crude oil 11.0%, ALCH (Kawaken Fine Chemical Co., Ltd. gelling agent) 0.8%, AF Solvent 7 (Nippon Oil Co., Ltd. aromatic component) Was 14.2% or less of a petroleum solvent, and was heated and stirred at 190 ° C. for 1 hour to obtain a gel varnish A. Soybean crude oil uses soy degummed oil obtained by squeezing and extracting soybeans and then removing lecithin, and has a water content of 0.2% or less, an acid value of 2.5, and an iodine value of 135.
[0031]
(Varnish production example 2)
A gel varnish B was obtained in the same manner as in Varnish Production Example 1 except that ALCH was changed to 1.0%.
[0032]
(Varnish production example 3)
In the same manner as in Varnish Production Example 1 except that soybean polymer oil was used instead of soybean crude oil, Gel Varnish C was obtained. Soy polymerized oil is a soybean degummed oil thermally polymerized to a viscosity of 1.6 poise.
[0033]
(Varnish production example 4)
A gel varnish D was prepared in the same manner as in Varnish Production Example 1 except that soybean crude oil was changed to 11.0% soybean white oil. Soybean white oil had a water content of 0.1% or less, an acid value of 0.04, and an iodine value of 138.
[0034]
Inks were prepared by the following composition, and inks of Examples 1 to 7 and Comparative Examples 1 and 2 were used.
Example 1
Indigo pigment Lionol Blue FG7330 (manufactured by Toyo Ink Manufacturing Co., Ltd.) 17.0%, gel varnish A 72.0%, AF solvent 7 10.8%, 2,2 dimethyl 1,3-propanediol 0.8. According to a conventional method, the mixture was kneaded using a three-roll mill at a blending ratio of 2%, and the ink of Example 1 was obtained with a tack of 6.8.
[0035]
(Example 2)
According to a conventional method, the blending ratio of indigo pigment Lionol Blue FG7330 is 17.0%, gel varnish A is 72.0%, AF solvent 7 is 10.8%, and 2,4 diethyl 1,5-pentanediol is 0.2%. The mixture was kneaded using a three-roll mill, and the ink of Example 2 was obtained as tack 6.8.
[0036]
( Reference Example 3) Mixing ratio of 17.0% of indigo pigment Lionol Blue FG7330, 72.0% of gel varnish A, 10.5% of AF solvent 7 and 0.5% of 2ethyl 1,3 hexanediol In accordance with a conventional method, the mixture was kneaded using a three-roll mill, and the ink of Reference Example 3 was obtained as tack 6.8.
[0037]
( Reference Example 4) As a blending ratio of 17.0% indigo pigment lionol blue FG7330, 73.0% in gel varnish B, 9.0% in AF solvent 7, and 1.0% in 1,6 hexanediol. According to the method, the mixture was kneaded using a three-roll mill, and the ink of Reference Example 4 was obtained as tack 6.8.
[0038]
(Example 5)
Three in accordance with a conventional method with a blending ratio of 17.0% indigo pigment lionol blue FG7330, 74.0% in gel varnish B, 7.0% in AF solvent 7 and 2.0% in 2-methyl-1,3-hexanediol The mixture was kneaded using a roll mill to obtain the ink of Example 5 as tack 6.8.
[0039]
( Reference Example 6) Mixing ratio of 17.0% of indigo pigment Lionol Blue FG7330, 76.0% of gel varnish B, 3.0% of AF solvent 7 and 4.0% of 2-ethyl-1,3-hexanediol In accordance with a conventional method, the mixture was kneaded using a three-roll mill, and the ink of Reference Example 6 was obtained as tack 6.8.
[0040]
(Example 7)
According to a conventional method, the blend ratio of indigo pigment Lionol Blue FG7330 is 17.0%, Gelvarnish B is 73.0%, AF Solvent 7 is 9.0%, and 2,2dimethyl-1,3-propanediol is 1.0%. The mixture was kneaded using a three-roll mill, and the ink of Example 7 was obtained as tack 6.8.
[0041]
( Reference Example 8) 17.0% of the indigo pigment Lionol Blue FG7330, 73.0% of Gel Varnish C, 9.0% of AF Solvent 7 and 1.0% of 2-ethyl-1,3-hexanediol According to a conventional method, the mixture was kneaded using a three-roll mill, and the ink of Reference Example 8 was obtained as tack 6.8.
[0042]
(Comparative Example 1)
Indigo pigment Lionol Blue FG7330 is 17.0%, Gel Varnish D is 72.0%, AF Solvent 7 is 11.0%, and the mixture ratio is kneaded using a three-roll mill according to a conventional method to obtain tack 6.8. The ink of Comparative Example 1 was obtained.
[0043]
(Comparative Example 2)
Indigo pigment Lionol Blue FG7330 is 17.0%, Gel Varnish D is 72.0%, AF Solvent 7 is 10.0%, Tridecanol is 1.0%. The ink of Comparative Example 2 was used as tack 6.8.
[0044]
(Print test evaluation)
The inks of the examples and comparative examples were subjected to a printing test on 20,000 sheets of each ink using Mitsubishi BT2-800 NEO off-wheel printing machine with 800 rpm and NPI-coated paper of 66.5 kg (manufactured by Nippon Paper Industries Co., Ltd.). The solid inking state, glossiness, and soiling state were compared. The fountain solution is 1.5% tap water from Aqua Magic NS (Toyo Ink Mfg. Co., Ltd.), and the lower limit of the water width is used to compare the printing state near the lower limit of the water width. In addition, 20,000 sheets were printed with a water dial value 2% higher.
[0045]
The evaluation results are shown in the following table.
────────────────────────────
Ink solid inking condition Glossy dirt ────────────────────────────
Example 1 Good Good None
Example 2 Same as above Same as above Same as above
Reference Example 3 Same as above Same as above Same as above
Reference Example 4 Same as above Same as above Same as above
Example 5 Same as above Same as above Same as above
Reference Example 6 Same as above Same as above Same as above
Example 7 Same as above Same as above Same as above
Reference Example 8 Same as above Same as above Same as above
Comparative Example 1 With missing outlines Same as above None
Comparative Example 2 Same as above Same as above Same as above ───────────────────────────
[0046]
Additional passing Limi施例1,2, Reference Examples 3 and 4, Example 5, Reference Example 6, Example 7, the ink of Reference Example 8, in printing with water tolerance lower limit, the earth printed material There was no generation of dirt, and no solid outlines were lost, and a good inking state could be maintained. Comparative Example 1 contains soybean white squeezed oil as a dry oil and does not contain diols, and Comparative Example 2 contains soybean white squeezed oil as a dry oil and contains tridecanol as a long-chain alcohol. It was impossible to satisfy both the prevention of background contamination and the prevention of the chipping of the solid portion. Moreover, since the ink of an Example uses soybean degummed oil as drying oil, the cost as drying oil was lower than soybean white squeezed oil.
[0047]
【The invention's effect】
As described above, the lithographic printing ink obtained by the method of the present invention reduces the cost of ink using soybean oil, and does not cause scumming in long-time printing and can be emulsified with dampening water. This has the effect of providing an ink capable of obtaining a good printed matter without the occurrence of such problems.

Claims (1)

In lithographic printing inks consisting of pigments, resins, drying oils, aliphatic diols and solvents,
The resin is a rosin-modified phenolic resin synthesized from rosin, alkylphenol, formaldehyde and polyol,
The drying oil is soybean crude oil having an acid value of 0.5 or more or its polymer oil,
The solvent is a petroleum-based solvent having an aromatic component content of 1% by weight or less,
Aliphatic diols are 2,2 dimethyl 1,3 propane diol, 2,2 diethyl 1,3
Propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3-pentanediol, 2-methyl-1,3-hexanediol, 2-methyl-1,3-heptanediol, 2,4 diethyl-1,5-pentanediol, 2, An ink for lithographic printing, which is 5 dimethyl 1,6 hexane diol.