JP2691403B2 - Fountain solution composition for lithographic printing - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a fountain solution composition for lithographic printing, and more particularly to a fountain solution of a continuous water supply type using a Moltonless roller. It relates to a fountain solution composition. (Prior Art) Lithographic printing is a printing method in which printing is performed using a printing plate in which a portion corresponding to an image portion is made of a grease-sensitive surface and a portion corresponding to a non-image portion is made of a hydrophilic surface. That is, the ink is attached to the oil-sensitive surface, the dampening solution is attached to the hydrophilic surface, and printing is performed using the repelling properties of the ink and water. However, the ink and the fountain solution must be supplied to the plate in an appropriately balanced manner. If the dampening solution is applied too much, it causes excessive emulsification of the ink, causing water loss, and delaying the drying, resulting in the back of the ink. On the other hand, if the supply amount of the dampening solution is too small, the ink adheres to the non-image area and causes soiling or the like. The initial purpose of the dampening solution is to prevent background fouling that occurs during printing, and therefore, the use of chromates and a combination of metaphosphoric acid and gum arabic to be created by the printing technicians themselves. There were many. After that, various types of water supply devices were developed to improve print quality and print workability, and with this, dampening water has changed drastically, and various functions are required rather than simply removing dirt. At the same time, it has become something that can deal with environmental problems. Looking at the changes in the water supply system, the water supply system invented by Dahlgren in the 1960s was revolutionary, and was imported into Japan from around 1965 and replaced with IPA (isopropyl alcohol). Was used as the dampening water for the first time. Initially, about 25% of IPA was used, but it gradually decreased from 5 to 15% in terms of printability and environmental issues. By using IPA instead of water, it was recognized that water can be supplied in a thin film, and it was found that it is appropriate for improving print quality, speeding up, and automation, and there have been many cases since the patent of Dahlgren expired. Continuous water supply devices have been developed one after another by domestic and overseas printing press manufacturers. Most continuous water supply systems developed since Dahlgren are not inker watering systems that send water to an inking roller such as Dahlgren, but rather are plate surface watering systems in which water is supplied by rubber rollers independent of the inking roller.
Roller material, number of rollers,
They differ in the configuration, presence / absence of a reverse slip nip, presence / absence of a rider roller, presence / absence of a roller between an inking roller and a watering roller, and the like. And all the water supply systems were designed from the beginning of development on the assumption that IPA was used. The continuous water supply system can make full use of its characteristics by using IPA. That is, a uniform and minimum amount of dampening solution can be supplied to the plate. Because water stabilization is fast when printing
Start-up becomes quicker (reduction of print damage). As described above, the use of dampening water with IPA added to the continuous water supply device is becoming common, but recently it is also used in the Molton system and the sleeve system because water can be squeezed and good printed matter can be obtained. I often see cases. But IPA
When adding to a dampening solution for use, there are the following problems. The first is the environmental problem, and its handling is restricted by the Occupational Safety and Health Act, the Fire Service Act, the Sewerage Act, and the like. According to the Industrial Safety and Health Act (Organic solvent poisoning prevention regulations), IPA
It is stipulated that the law shall be applied when using a substance containing 5% or more, and a local exhaust device must be installed when adding 5% or more to the dampening solution. In recent years, environmental regulations have been strengthened especially by the organic solvent poisoning prevention rule, and due to the entry of labor standards supervision, the IPA concentration is 5%.
It has become obligatory to stay within. However, when the IPA concentration is within 5%, a good printing effect cannot be obtained, and a continuous water supply device developed for the purpose of responding to high speed cannot sufficiently exhibit its true value. In addition, IPA is designated as a quaternary petroleum alcohol, and it must be handled in the same manner as gasoline, and is subject to regulations under the Fire Service Law for storage and use. According to the Sewerage Law, wastewater has a hydrogen ion concentration of pH 5 or less or 9 or more, and biochemical oxygen demand (BOD) of 600 mg /
In these cases, the placement of abatement facilities is compulsory.
IPA is related to the latter, and it is necessary to control not only the pH of wastewater but also the BOD. Another major problem with using IPA is cost. The amount of IPA used and the cost of IPA, which is equipped with a continuous water supply system, are double-sided. In order to improve such problems of IPA, Japanese Patent Publication No. 61-5
Japanese Patent No. 5480 discloses a device for reducing the alcohol content to 10% by weight or less. However, simply reducing the content of IPA is not sufficient. Since the prescribed amount specified by the Organic Solvent Poisoning Prevention Regulation is 5% by weight or less, the content is too large and insufficient, and as long as IPA is contained, the problem of instability of the liquid concentration due to evaporation of IPA Is inevitable. For the volatility problem of volatile alcohols, U.S. Pat.No. 3,877, to exclude volatile alcohols,
There are also attempts to use butyl cellosolve in 372, and more complex mixtures shown in U.S. Pat. No. 4,278,467. This US patent contains a nonionic compound
A fountain solution without IPA is shown. JP-A-57-19969
The contents of the gazette No. 3 are also the same, which is a dampening water containing 2-ethyl-1,3-hexanediol and the like. However, as a problem of dampening water containing no volatile alcohol, especially when printing is performed with a dampening device of a continuous water supply type such as Dahlgren, a water squeezing roller (Metering rol) is used.
Ink adheres to the surface of the ler) and stains it, which disrupts the balance of water supply. If printing is continued for a long time, the dots in the printed image may become entangled, and dampening water The water width of the apparatus, that is, the latitude of the dampening water scale with which an appropriate printed matter can be obtained is narrow, and there is a drawback that the printing operation is difficult. Further, JP-A-58-176280 discloses a fountain solution in which an IPA substitute selected from alcohol and glycol ether ester and a water-soluble polymer are combined, but the above-mentioned water metering roller (Metering roller) Problems such as ink stains, entanglement of printed images, and narrow water width still remain, and the current situation is that we have not obtained the performance that can completely replace IPA. Also, as shown in U.S. Pat. No. 4,641,579, a fountain solution containing butyl cellosolve and a thickening agent is also disclosed, but butyl cellosolve is contained in a second type organic solvent and causes harm to the human body. It is harmful and not only easily absorbed from the skin, but also has risks such as kidney damage and neuropathy. Even if the concentration is low, long-term use is not preferable. As described above, there are many IPA substitute dampening waters disclosed so far, but there are problems in printing performance and problems to be solved, and complete IPA substitute dampening water has not been obtained. The current situation. (Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide an IPA containing no IPA.
It is to provide an alternative dampening solution. It is another object of the present invention to provide an IPA alternative dampening solution having a printing effect equal to or greater than that of an IPA-containing dampening solution when used in a continuous water supply type dampening device. Another object of the present invention is to provide a highly safe IPA for the human body.
It is to provide an alternative dampening solution. Another object of the present invention is to provide an IPA alternative fountain solution with less evaporation and less change in liquid composition. It is another object of the present invention to provide an IPA alternative dampening solution having a low odor in a state of using a dampening solution. Another object of the present invention is to provide an inexpensive IPA.
It is to provide an alternative dampening solution. (Means for Solving Problems) As a result of various analyzes of physical properties of the dampening water containing isopropyl alcohol in order to improve these problems, the present inventor has determined that 2 The present invention has been completed by finding out four points. That is, the present invention is a fountain solution composition for lithographic printing containing water, a thickener and a water-soluble organic solvent, and after formation of a new surface of the composition on the printing plate, 10 ^-1 seconds later at the latest. The composition has a dynamic surface tension of 30-45 dyne at a temperature of 15 ° C.
/ cm range, and the viscosity of the composition is at a temperature of 15 ° C.
And a fountain solution composition for lithographic printing containing no isopropyl alcohol, which is in the range of 2.0 to 7.0 centistokes. The first point in the present invention is a factor of the dynamic surface tension of the dampening solution. In order to provide printability equivalent to that of IPA-containing dampening solution, at least as long as a new surface is formed
The dynamic surface tension after 10 ^-1 seconds is 30-45 dyne / cm at a temperature of 15 ° C.
It has become clear that the fountain solution must have a liquid property in the range described above. Here, the dynamic surface tension will be briefly described. Dynamic surface tension is defined as described in the interface textbook, for example, "Surface and Colloid Science", 3, p28 (1971).
Wiley Interscience
There is a commentary on Defay et al. (R.Defay, G.Ptr). In this commentary, "when the surface of a solution is suddenly expanded and the liquid inside comes out to the surface, the composition of the newly formed surface is the same as the composition inside the solution, if this expansion is fast enough. That is, if the surface area spreads faster than the diffusion rate of the solute, the surface condition at the moment of new formation is zero age, and the surface tension at zero time is the pure dynamic surface tension. ). As the surface ages, the surface tension decreases, but this transient individual value is taken as the intermediate dynamic surface tension (in
termediate dynamic surface tension). In this way, the dynamic surface tension gradually decreases from the net dynamic surface tension value to reach an equilibrium value. This final equilibrium value is the static surface tension.
That. It is described. The above phenomenon is briefly described as shown in FIG.
That is, the value of the surface tension (γ) changes with the lapse of time t after the new surface is formed. At the moment when a new surface is formed, that is, when the aging time is zero (t = 0), γ of a surface having the same concentration as that of the internal liquid showing no adsorption is shown
_It has a value of pure dynamic surface tension of _0, but when time t ₁ has elapsed, it means that it has a dynamic surface tension of γ ₁ .
This definition applies to most other textbooks as well. As mentioned above, regarding the surface tension that has not reached equilibrium,
Considering it again, it is necessary to reconsider how the values displayed in conventional numerical tables and handbooks correspond to the states. The values given in these tables are values corresponding to the concentration and temperature at the time of measurement, and both are “static” surface tensions (γ _s ). The term "surface tension" and physical quantity found in the patent publications on dampening waters up to now are also values of γ _s . That is, the value at which the surface tension reached equilibrium, and there was discussion about "static" surface tension. Conventional surface tension measurement methods include the Du Noy ring method and Wilhelmy.
Typical examples are the plate (Wilhelmy plate) method and the capillary rise method, which all measure "static" surface tension. Generally speaking, tracking and measuring changing phenomena of moving objects is much more difficult than measuring stationary or equilibrium phenomena. In fact, there are very few studies based on the measurement of the value of d [physical quantity] / dt containing a factor of time (t) in any region. Even in surface chemistry books, the number of pages on dynamic surface tension and adsorption kinetics is very small. However, even considering only the interfacial phenomenon, it is the reality that there are more "moving" systems in the scene where it is desired to control the properties of the interfacial surface and to successfully process the interfacial phenomenon in practice. This is also true, for example, when considering the behavior of dampening water on a printing press. That is, an offset sheet-fed printing machine can print 13
In the case of 000 rpm, offset rotary press, the dampening water supply roller rotating in contact with the plate cylinder (plate cylinder) rotates at a high speed of 50,000 rpm per hour, and rotates at a higher speed than this. It will be. Therefore, the dampening water must be instantly produced with new surfaces one after another by the dampening water roller rotating at a high speed. The time required for the dampening water to form a new surface of 1 cm ² at this time is about 10 ^-3 seconds. In other words, when considering the spread of dampening water and the surface free energy, that is, the surface tension on a printing machine that rotates at high speed, "dynamic" surface tension is important, and conventional "static" surface tension cannot handle it at all. I understand. The following phenomenon is mentioned as an example which can explain the above very well. Excellent printing effect of IPA-containing dampening solution is IPA
It has heretofore been said that the addition of the compound reduces the surface tension of the dampening solution and improves the wettability. Therefore, examples of adding a surfactant as an IPA substitute in order to reduce the surface tension are often found in the patent publications so far. When the surface tension of the dampening water containing the surfactant is measured by, for example, the Du Noy ring method,
Certainly, a low surface tension value equivalent to that of the IPA-containing dampening solution can be obtained. However, when actual printing is performed by using the dampening solution with, for example, a Dahlgren type dampening solution supply device, good printing cannot be performed, and various printing troubles occur. The printing ink adheres to the water squeezing roller and the water roller (chrome roller), causing not only severe dirt but also soiling of printed matter. Therefore, in order to compare the dynamic surface tension of a dampening solution containing a surfactant and a dampening solution containing IPA, for example, CAHN (USA)
Dynamic surface tension measuring device (NOW-INSTANT WILHELMY DYNA
MIC SURFACE TENSION ACCESSORY) has revealed that there is a very large difference between the two. This CAHN dynamic surface tension measuring device is a device that can measure the dynamic surface tension after a time lapse of 10 ⁻¹ second from the generation of a new surface. As a result of the measurement, the dynamic surface tension of the dampening water containing IPA showed almost the same value as the static surface tension (measured value by the Du Noy ring method), whereas it contained the surfactant. The dynamic surface tension of the dampening water was about 71 dyne / cm, which was almost the same as the surface tension of pure water of 72.5 dyne / cm, and the function of lowering the surface tension of the surfactant was almost ineffective. It became clear that it was. Dynamic surface tension of fountain solution containing surfactant (after 10 ^-1 second)
However, that it has hardly decreased, and that printing does not work well with the surfactant-containing fountain solution as described above,
They correspond very well and are aligned. The fountain solution on the press is always in a dynamic state during printing, and 10 ^-1 to 10 ^-3 seconds after the new surface is formed by the fountain solution supply roller, until the desired surface tension is reached. It is necessary to be lowered. In this regard, in the fountain solution containing IPA, the surface tension is reduced without any problem. In the case of the fountain solution containing a surfactant, the dynamic surface tension is hardly reduced, so that it is considered that this will cause a great hindrance to practical printing. In other words, the fountain solution containing IPA has the function of lowering the surface tension in response to the high rotation speed of the printing machine, so the lithographic plate surface and rollers can be well wetted with water and contribute to an excellent printing effect. The dampening water containing the activator does not have any surface tension lowering function on a printing machine that rotates at a high speed, so that the above-mentioned printing trouble occurs. Considering how much time has passed since the generation of a new surface, the dynamic surface tension becomes a problem.
This depends on how fast the new surface forms on the press. In other words, the rotation speed of the printing press,
Although it depends on the diameter of the plate cylinder, the diameter of the dampening roller in the dampening device, etc., when calculating for printing machines of various sizes, the time from the generation of new surface is at least 10 ^-1.
After a few seconds, it becomes apparent that the surface tension needs to be reduced to the required value. In the present invention,
It is on this basis that the aging condition of the dynamic surface tension is set 10 ^-1 seconds after the new surface is formed. Next, the value of the dynamic surface tension of the present invention will be described. The value of dynamic surface tension is preferably lowered to the range of 30 dyne / cm to 45 dyne / cm. The main reasons are the prevention of floating ink stains and the improvement of the wettability of water on the lithographic plate surface. When forming an image on a lithographic printing plate while maintaining the balance between the dampening solution and the ink, if the surface tension of the water is too large compared to the surface tension of the ink, the ink becomes a thin film and the dampening solution becomes The phenomenon of diffusion to the surface occurs. Spreading coefficient is also used as a measure for predicting the spread of the oil film on the water surface. As a simple method, a dampening solution having various surface tensions is adjusted, and a well-kneaded ink is prepared. There is a method of examining the spread of the oil film by dripping on the surface of the dampening solution. When the value of the surface tension of the dampening water in which the oil film does not spread is examined by this method, it becomes 45 dyne / cm or less. The reduction of the dynamic surface tension of the dampening water can be achieved by adding an organic solvent to the water, but the limit is 30 dyne / cm due to the aqueous solution, and
Good printing effect can be obtained in the range of yne / cm to 45 dyne / cm. Examples of the water-soluble organic solvent capable of lowering the dynamic surface tension of the dampening water include alcohols, polyhydric alcohols, ethers and esters. Examples of alcohols include normal butyl alcohol, normal amyl alcohol, normal hexyl alcohol, 2-hexyl alcohol,
Methylpentanol 1, secondary hexyl alcohol, 2-
Ethyl butyl alcohol, secondary heptyl alcohol, heptanol 3, 2-ethylhexyl alcohol, benzyl alcohol and the like. As polyhydric alcohols,
For example, there are ethylene glycol, hexylene glycol, octylene glycol, diethylene glycol, and the like. Examples of the ethers include ethylene glycol monoethyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monoethyl ether, and diethylene glycol mono-normal-hexyl ether. . Examples of the esters include diethylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate. These water-soluble organic solvents, in order to impart a dynamic surface tension lowering function, because it is to be contained in the fountain solution,
Needless to say, it is preferable to add as little as possible. The present inventor studied a water-soluble organic solvent having a large dynamic surface tension lowering function by adding a small amount, and found that an organic solvent having low solubility in water can greatly reduce the dynamic surface tension by adding a small amount. I found it. 20
If the organic solvent has a solubility in water of about 0.5 to 80% by weight, preferably 0.5 to 10% by weight,
The dynamic surface tension can be greatly reduced. The use solution of the fountain solution of the present invention can contain about 0.5 to 15% by weight of these water-soluble organic solvents. Further, from the viewpoint of the printing work environment, it is preferable that the dampening water is highly safe for the human body. According to the "Organic solvent poisoning prevention rule" (hereinafter referred to as the organic rule), the organic solvent is
Safety measures are mandatory. It is said that there are several hundred kinds of organic solvents, but 54 kinds are classified by the standard that they are obviously harmful to the human body and that they are currently used in a relatively wide range. It is subject to organic regulation. From the viewpoint of safety, the organic solvent used in the present invention is preferably a water-soluble organic solvent that is not subject to the organic rules. Further, considering the printing work environment, an unpleasant odor is not preferable, and an odorless one is preferable. Furthermore, in order to stabilize the liquid composition of the dampening water, an organic solvent that is difficult to evaporate is preferable, and one having a low vapor pressure, for example, a vapor pressure at 20 ° C. of 20 mmHg or less, more preferably an organic solvent of 5 mmHg or less. It is preferably used. In addition, since the dampening water always comes into contact with the printing ink on the printing machine, the organic solvent used is preferably inert to the printing ink for lithographic printing, and the pigment, dye, etc. in the ink. It is not preferable that the additive of "cries out" in the fountain solution causes troubles in the case of long printing. From these various viewpoints, as the water-soluble organic solvent for reducing the dynamic surface tension, octylene glycol, ethylene glycol diethyl ether, ethylene glycol monophenyl ether, ethylene glycol monohexyl ether, and the like are more preferable. . The second point is a factor of the viscosity of the dampening solution, which has been revealed by analyzing the liquid properties of the dampening solution containing IPA. As IPA is added to water, its viscosity gradually increases, with a peak value of the viscosity in the region where the content of IPA is about 50%, and the viscosity further decreases when the content of IPA is further increased. This thickening phenomenon caused by adding IPA to water is presumed to be caused by hydrogen bonding between water and IPA. Next, consider why the viscosity of the dampening solution is important. In the continuous water supply method, water passes between the nips of the rollers, but one of the roll nips is a chrome roller and the other is a rubber roller, and the gap between the nips through which the water passes is a rubber layer concave. You can do it. The characteristics of this portion can be generally treated as a problem that fluid is present between curved surfaces in rolling contact. That is, since the fluid exists in the nip portion, when the fluid passes through the nip, the fluid has a certain pressure distribution, and the surface of the roller is deformed according to the pressure distribution. The fluid path changes due to this deformation, and the pressure distribution changes, so that the pressure distribution of the fluid and the roller surface deformation of the nip portion are balanced. This phenomenon is called elastohydrodynamic lubrication (EHL), but according to this EHL theory, the minimum thickness of dampening water passing through the nip part is the viscosity of dampening water, the average roller peripheral speed,
It is a function of the relative radius of curvature, the nip line pressure, the equivalent elastic modulus, and the like. That is, the thickness of the dampening solution passing through the dampening solution roller nip increases as the dampening solution viscosity increases. The dampening solution itself must have a certain viscosity or higher in order to ensure a certain amount of a stable water film when the dampening solution passes between the nips of the rubber roll and the metal roll.
Supported by L theory. Since the dampening solution containing IPA has a viscosity of 1.2 to 3 centistokes (15 ° C.) depending on the content of IPA, the dampening solution can pass between the roller nips as a constant water film. The printing effect has been obtained. It can be said that the "viscosity" of the dampening water gives the "water pumping effect" and the "water transfer effect" in the continuous water supply system. The viscosity of the dampening water is described in JP-B-61-55480 and JP-A-58-176280, and there is no contradiction with the effect of the viscosity in the present invention. However, in Japanese Patent Publication No. 61-55480, only the viscosity of the dampening water is noted, and the dampening water described in this publication is considerably inferior in printing effect as compared with the IPA-containing dampening water. all right. That is, Japanese Examined Japanese Patent Publication 61-55
It was found that the following big problems occur when the fountain solution as shown in the example of Japanese Patent No. 480 is prepared and printing is performed. Ink adheres to the surface of the water squeezing roller and becomes dirty. The ink melts in the dampening water and the dampening water itself is colored in the color of the ink. The blanket becomes more dirty than the fountain solution containing IPA, and when printing is continued for a long time, the printing paper also becomes smeared. Normal printed matter is obtained at the start of printing,
If you continue to print 1000 to 1500 sheets, "entanglement" will occur in the halftone dots of the printed image, making it impossible to print a large number of copies in a stable manner. The dot gain of the entire printed material is larger than that of the fountain solution containing IPA (mechanical dot gain). As a result of repeated experiments on the above problems, it was concluded that defining only the viscosity of dampening water cannot be a substitute for IPA-containing dampening water. In addition, IPA
As a result of earnest research to analyze the effect of contained dampening water,
It has been clarified that by controlling the two factors of dynamic surface tension and viscosity in a certain region as the physical properties of the fountain solution, a printing effect equivalent to or better than that of the IPA-containing fountain solution can be obtained. That is, it has been found that when either one of the dynamic surface tension and the viscosity is out of the predetermined range, a very insufficient printing effect can be obtained. The thickener used in the present invention, carboxymethyl cellulose, carboxyethyl cellulose, aminoethyl cellulose, ethyl cellulose, sodium alginate, propylene glycol alginate, tragacanth gum, crystal gum, hydroxyethylated starch, hydroxypropylated starch, phosphate starch,
Starch acetate, carboxymethylated starch, carboxyethylated starch, cyanoethylated starch, dialdehyde starch, cyclodextrin, branched cyclodextrin, polyvinylpyrrolidone, vinyl acetate maleic acid copolymer, vinyl acetate crotonic acid copolymer, vinyl acetate acrylic Acid copolymer, polyvinyl alcohol maleic acid copolymer, polyvinyl methyl ether, styrene maleic acid copolymer, styrene crotonic acid copolymer, polyacrylic acid, polyacrylic acid soda, polymethacrylic acid salt, and derivatives thereof. Water-soluble polymer compounds selected from can be mentioned. These may be used alone or in combination of two or more. The viscosity of dampening water containing these thickeners is of course affected by pH, addition of salts, intensity of stirring, temperature, etc., but it greatly changes depending on the molecular weight of the water-soluble polymer compound. . Therefore, the viscosity of dampening water is 2.0-7.0 at a temperature of 15 ° C.
The thickener concentration must be adjusted to be centistokes. The amount of these thickeners to be added depends on the type of the thickener, but is suitably about 0.005 to 10% by weight of the fountain solution composition. In the present invention, all the acids used in ordinary dampening water can be used for pH adjustment. For example, organic compounds such as phosphoric acid, citric acid and gluconic acid, inorganic compounds such as nitric acid, sulfuric acid and dichromic acid, and sodium salts and ammonium salts of the above acids can be used. When the pH is set to 3.0 or less, the viscosity of the aqueous solution of the water-soluble compound decreases, and the effect decreases. Further, the fountain solution composition for lithographic printing according to the present invention can be used not only in the continuous water supply system but also in the conventional system (Molton system, etc.). (Examples) Next, the present invention will be specifically described with reference to examples. %
Indicates% by weight unless otherwise specified. Example 1 The viscosity of the above dampening water is 2.56 at 15 ℃ with a B type viscometer.
It was Centistokes. The dynamic surface tension of the new surface after 10 ^-1 seconds was 43 dyne / cm. Offset printer Harris Aurelia equipped with continuous water dampening device
When a printing test was carried out with 125 (manufactured by Marubeni Harris Printing Machinery Co., Ltd.), the water squeezing roller was not stained at all, and the printed matter was not stained, and a printing effect with excellent tone reproducibility was obtained. Further, there was no bleeding of the ink in the dampening water, and even after printing 30,000 sheets, there was almost no coloring by the ink in the dampening water and it remained colorless and transparent. For the comparative test, Comparative Liquid B was used as fountain solution and printed under the same printing conditions. It was found that the solution A of the present invention exhibited almost the same performance as the comparative solution B. Contamination of the blanket was slightly better with the liquid A of the present invention. The ink used was Space Color CAPS-GN type magenta from Dainippon Ink and Co., Ltd., and the printing plate was a PS plate (FPS manufactured by Fuji Photo Film Co., Ltd.).
-II) was used after plate making. After the fountain solution composed of the composition (unit: parts by weight) as shown in <Table 1> was prepared, its liquid physical properties were measured.
The liquid property data as shown in Table 2> were obtained. Printing machine SPRI
NTL-225B (Komori Printing Machinery Co., Ltd., sheet-fed two-color machine) continuous water supply type dampening device Komorimatic (KOMORIMATIC), using these seven types of dampening water, printing practical test did. As a lithographic printing plate, offset PS plate FPD-I
I (manufactured by Fuji Photo Film Co., Ltd.) was used to make a 4-stage clear reproduction. As the printing ink, Toyo King New Bright G Hongkou (manufactured by Toyo Ink Co., Ltd.) was used. The evaluation standard of the printing performance is as follows. Also, in Table 2, "Water amount adjustment latitude of dampening device" indicates the range "water width" in which the water amount can be adjusted. The larger the number, the wider the "water width", and the easier it is to print. Become. If the amount of dampening water supplied is too large, the "water loss" phenomenon occurs. Conversely, if the amount of dampening water is too small, "ground fouling" occurs, but "water width" means "water loss" and "ground loss". The range in which "dirt" does not occur is indicated by the difference in the water amount scale of the dampening device. The printing results are shown in Table 2 and the dampening solution N of the present invention
The o.1 has better soiling on the blanket than the dampening water No.2 containing 25% by weight of IPA, and the water width of the dampening device (latitude for adjusting water volume) is also better than that of the IPA-containing dampening water No.2. It was widely confirmed that it has sufficient performance as an IPA substitute dampening solution. Comparative test liquid No. 3 is the formulation described in Japanese Patent Publication No. 61-55480, excluding IPA. No. 2 (IPA-containing fountain solution)
It can be seen that sufficient performance is not obtained as compared with. That is, in the dampening water described in Example 1 of Japanese Patent Publication No. 61-55480, the dynamic surface tension (70.5 dyne / cm) is almost the same as that of pure water, indicating that IPA cannot be made zero. ing. Next, Test Solution No. 4 was prepared by adding only a surfactant in order to reduce the surface tension of the dampening water. The stains on the heater ring and the ink on the bracket are severe, and the printed matter also has background stains.
Not practical at all. When the physical properties of the liquid were checked, the static surface tension certainly dropped to 34.5 dyne / cm, but the dynamic surface tension was almost the same as that of pure water (72.5 dyne / cm). It is clear that the activator does not have a dynamic surface tension lowering function, which is in good correspondence with the printing practice test results. Next, with the test liquid No. 5, the effect of only the thickener was examined. It can be seen from the comparison with Test Liquid No. 4 that the dirt on the water squeezing roller is reduced by increasing the viscosity. However, with Test Liquid No. 5, since the dynamic surface tension did not decrease, the oil film of the ink spreads over the water, causing a problem that the dampening water was markedly colored. Example 3 Fountain solution concentrate for aluminum plate (etching solution) The viscosity of the fountain solution of the present invention (H) is 2.
It was 13 centistokes (15 ° C). The dynamic surface tension of the new surface after 10 ^-1 seconds was 41.5 dyne / cm. On the other hand, a liquid (C) having the following composition was prepared. (A) Liquid (B) Liquid (C) Liquid (a) Liquid 99.2 g (3.5ounces) (b) Liquid 2849.2 g Water 1050 g Total 3800 g (1 gallon) (c) Liquid is the wetness shown in Example 1 of US Pat. No. 4,461,579. This is the water that has been adjusted. When the physical properties of this dampening water (solution (c)) were examined, the viscosity was 1.
7 centistokes and since the new surface was created 1
The dynamic surface tension after 0 ^-1 second was 48 dyne / cm. In order to compare this liquid (c) with the liquid of the present invention (H), a printing practical test was carried out under the same printing conditions as in Example 1. The printing effect of the liquid of the present invention (H) was good, but
With the liquid (c), there was a large amount of ink bleeding into the dampening water, and after printing 20,000 sheets, the dampening water was severely colored, and stains on the water boat and dampening water circulation pipe were also noticeable. This can be caused by
(C) It is considered that the function of lowering the dynamic surface tension of the liquid was insufficient. Furthermore, with liquid (c), 3000 from the start of printing
When the number of sheets exceeded, ink came to adhere to the mitering roller (water squeezing roller), and when printing was continued, entanglement occurred in the halftone dot portion of the printed image, causing troubles in tone reproduction. Moreover, when comparing the water widths of the dampening devices, the liquid of the present invention (H) had a latitude of 5.0, while the liquid (c) had a latitude of only 1.5. It shows that the viscosity of the liquid (c) is insufficient. In the liquid (H) of the present invention,
No trouble was found with the liquid (c), and continuous printing of 50,000 sheets could be stably performed. Example 4 The above-mentioned dampening water and the liquid of the present invention (I) have a viscosity of 2.22 centistokes (15 ° C) as measured by a B-type viscometer, and a new surface is formed.
The dynamic surface tension after ^-1 second was 35 dyne / cm. On the other hand, a fountain solution (d) liquid having the following composition was prepared. (D) Liquid However, the alcohol substitute I is composed of the following contents. Also, Prisco R855 etchant is commercially available. The liquid (d) shows Example 4 described in JP-A-58-176280. When the physical properties of this dampening water (d) were examined, the viscosity was 1.61 centistokes at 15 ° C, and the dynamic surface tension after the formation of a new surface was 49
It was dyne / cm. On the other hand, a fountain solution containing IPA was simultaneously evaluated as a blank test. The composition of this blank test solution (J) is as follows. When the liquid properties of this blank test liquid (J) were examined, the viscosity was 2.23 centistokes (15 ° C.), and the dynamic surface tension after forming new surface for 10 ⁻¹ seconds was 36.5 dyne / cm. As described above, the printing practical test was performed on the three types of dampening water under the same printing conditions as those shown in Example 2, and the results are summarized in Table 3. The evaluation criteria of ⊚, ◯, Δ and × in the table are exactly the same as those shown in <Table 2> of Example 2. From this,
The fountain solution (I) of the present invention was not only found to have a remarkably excellent printing effect as compared with the solution (d), but was also comparable to the blank test solution (J) containing isopropyl alcohol. We were able to confirm that it had better performance. The above test results show that the decrease in the dynamic surface tension of the fountain solution is 45
Dyne / cm or less and the viscosity of the dampening water of 2.0 tenti Stokes (15 ° C) or more clearly show that it is an essential condition for the IPA substitute dampening water. (Effects of the Invention) The fountain solution composition of the present invention exhibits a printing effect equivalent to or better than that of a conventional IPA-containing fountain solution, even though it does not contain IPA, and does not contain IPA. It is extremely advantageous for hygiene.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a drawing for explaining changes in surface tension with time.

   ────────────────────────────────────────────────── ─── Continuation of front page    (56) Reference JP-A-54-114302 (JP, A)                 Special table Sho 59-502097 (JP, A)                 Japanese Patent Publication Sho 61-55480 (JP, B2)

Claims (1)

(57) [Claims] In a fountain solution composition for lithographic printing containing water, a thickener and a water-soluble organic solvent, the movement of the composition at least 10 ^-1 seconds after the new surface of the composition is formed on the printing plate. Isopropyl alcohol, characterized in that its surface tension is in the range of 30-45 dyne / cm at a temperature of 15 ° C, and the viscosity of the composition is in the range of 2.0-7.0 centistokes at a temperature of 15 ° C. No fountain solution composition for lithographic printing. 2. To reduce the dynamic surface tension of the fountain solution composition,
The water-soluble organic solvent selected from alcohols, polyhydric alcohols, ethers and esters, and having a vapor pressure at 20 ° C. of 20 mmHg or less is contained in an amount of 0.5 to 15% by weight. A fountain solution composition for lithographic printing. 3. Dampening water viscosity 2.0-7.0 centistokes (15 ℃)
Thickener for adjusting to the range of carboxymethyl cellulose, carboxyethyl cellulose, aminoethyl cellulose, ethyl cellulose, sodium alginate, propylene glycol alginate, tragacanth gum, crystal gum, hydroxyethylated starch, hydroxypropylated starch, phosphate starch, acetic acid. Starch,
Carboxymethylated starch, carboxyethylated starch, cyanoethylated starch, dialdehyde starch, cyclodextrin, branched cyclodextrin, polyvinylpyrrolidone, vinyl acetate maleic acid copolymer, vinyl acetate crotonic acid copolymer, vinyl acetate acrylic acid copolymer Coalesce, polyvinyl alcohol maleic acid copolymer, polyvinyl methyl ether, styrene maleic acid copolymer, styrene crotonic acid copolymer, polyacrylic acid, sodium polyacrylate, polymethacrylate, and derivatives thereof. The fountain solution composition for lithographic printing according to claim 1, characterized in that the water-soluble polymer compound is contained in an amount of about 0.005 to 10% by weight. 4. The fountain solution composition for lithographic printing according to claim 3, wherein the thickening agent is carboxymethyl cellulose. 5. The fountain solution composition for lithographic printing according to claim 3, wherein the thickening agent is polyvinylpyrrolidone. 6. The fountain solution composition for lithographic printing according to claim 3, wherein the thickener is carboxymethylated starch. 7. The fountain solution composition for lithographic printing according to claim 2, wherein the water-soluble organic solvent is octylene glycol.