JP2008238714A - Processing method of dampening water, and processor of dampening water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing method of dampening water, and a processor of dampening water capable of removing impurities causing troubles in printing from a dampening water and holding the intrinsic effect of the dampening water in offset printing. <P>SOLUTION: The processing method of the dampening water used in the offset printing includes processing the dampening water using a filter filled with a resin having acid group subjected to salt exchange with cations of divalent or more. The processing device of the dampening water used in the offset printing includes a filter cartridge 4 processing the dampening water and characterized in that the filter cartridge 4 is the filter cartridge 4 filled with the resin having the acid group subjected to the salt exchange with the cations of divalent or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dampening water treatment method and a dampening water treatment apparatus. More specifically, a dampening water treatment method and dampening water for treating dampening water used in offset printing to stabilize the dampening water performance and maintaining the original dampening water performance. The present invention relates to a processing apparatus.

  Lithographic printing is a printing method that skillfully uses the property that water and oil do not essentially mix, and the printing plate surface consists of an area that receives water and repels oil-based ink, and an area that repels water and receives oil-based ink. Thus, the former is a non-image area and the latter is an image area. In the lithographic printing method, a non-image area is generally moistened with a fountain solution to increase the interfacial chemical difference between the image area and the non-image area. Ink receptivity is increased.

Usually, nitric acid, phosphoric acid, phosphonic acid, sulfuric acid, hydrochloric acid, or salts thereof are added to the fountain solution in order to maintain ink repellency in the non-image area of the lithographic printing plate. In particular, phosphoric acid and / or phosphate, phosphonic acid and / or phosphonate are effectively used to increase the hydrophilicity of non-image areas of the printing plate.
On the other hand, the fountain solution is usually supplied in the form of a concentrated solution, and is diluted with tap water or well water during use. The calcium ions contained in the tap water and well water react with the components in the dampening water to produce insoluble precipitates, and these precipitates adhere to the rolls of the printing press and have a negative effect on printing. May be.

Furthermore, in recent years, recycled paper, which is increasing from the viewpoint of environmental conservation, and light weight with a coating layer on the surface containing a large amount of polyvalent metal salts such as calcium carbonate to increase the whiteness of recycled paper. Recycled coated paper is increasing, and when printing using these printing papers, the result of the fountain solution dissolving calcium carbonate from the surface coat layer of the paper under long-term continuous use conditions of the fountain solution The concentration of calcium ions in the fountain solution tends to increase.
On the other hand, calcium is present as calcium ions in raw water (tap water and well water for diluting the concentrate for dampening water), and particularly when hard water with high hardness is used as raw water, there are many calcium ions. Also, printing paper may contain calcium carbonate as a filler, and ink may contain calcium carbonate as an extender pigment. In particular, red ink pigments are produced by calcium lake treatment, and therefore contain calcium, and it is known that some of these pigments are easily eluted as calcium ions into the fountain solution.

  The calcium ions in the fountain solution thus increased may react with the aforementioned phosphorus compounds such as phosphoric acid, phosphate, phosphonic acid, and phosphonate to form insoluble salts. Such insoluble salts are deposited and deposited on the image area of the printing plate, or deposited and deposited on the ink rolls of the printing press, which impairs the normal transferability of the ink, resulting in poor ink landing properties. In some cases, such problems as reduction and so-called roller strip (also called ink peeling on the ink roll, also called roller flaking) occur.

  Conventionally, various methods have been proposed as means for solving the above-mentioned problem of phosphorus compound and calcium precipitates. For example, in order to reduce calcium ions in the fountain solution, it has been proposed to use a water softening device in the raw water to make it soft, and in addition, a treatment of adding a chelating agent such as EDTA to the fountain solution as a calcium sequestering agent Proposed (see, for example, Patent Documents 1 and 2), and a method for concealing calcium without promoting calcium elution by the combined action of a chelating agent and an emulsification inhibitor has been proposed (see, for example, Patent Document 3). However, even in these methods, the occurrence of roller flaking can be slightly delayed but not prevented.

A dampening solution that does not use phosphorus compounds (phosphoric acid and / or phosphate, phosphonic acid and / or phosphonate, etc.) is proposed as a means to prevent deposits of phosphorus compound and calcium and suppress roller baldness. (For example, see Patent Document 4 and Patent Document 5).
However, even if the fountain solution does not contain a phosphorus compound, the phosphorus compound is also blended in the ink. Since accumulation proceeds in water, the fountain solution that has been used for a certain period of time may contain a significant concentration of phosphorus compounds. Even when the fountain solution does not contain a phosphorus compound in the new solution, it will contain a phosphorus compound when used for several days, so these form an insoluble salt with calcium ions in the dampening water, and the ink roller As a result, precipitation on the top occurred, and the occurrence of roller baldness could not be prevented.

  As a means for stabilizing the performance of the fountain solution and maintaining the ability at the time of the new solution, a method of removing the mixed impurities by filtration is conceivable, and the use of a fountain solution filtering device has been proposed. As a filtering device that filters and recycles the fountain solution, for example, a fountain solution filtering device that uses a plurality of filters including a Breez type filter has been proposed (see Patent Document 6). Patent Document 6 uses a pleated filter, specifically, a filter in which a filter material in which an inorganic material such as diatomaceous earth is mixed with a nonwoven fabric such as polypropylene fiber is folded into a tubular shape, and high-precision filtration is performed. A possible configuration is illustrated. By filtering the fountain solution with the filtration device having such a configuration, impurities are removed and the fountain solution is always circulated in a clean state, and can be used without being exchanged for a long period of time.

  However, the filter device can filter ink, oil, paper powder, powder, etc. mixed in the fountain solution, but removing substances dissolved in the fountain solution in an ionic state is not possible. Impossible. In the process of repeated filtration, phosphorus compounds and hardness substances (metal ions such as calcium and magnesium) that are eluted from the ink and heavy metals that are eluted from the pigment of the ink accumulate in the fountain solution, so these have a concentration. When it reaches a certain level, it reacts with the phosphorus compound to form a water-insoluble salt and precipitates on the ink roller of the printing press. Therefore, even if the filtering device is used, the problem of causing roller flaking cannot be prevented.

JP-A-11-105449 Japanese Patent Laid-Open No. 4-235096 JP 2001-105764 A JP 2004-106531 A JP 2005-53189 A JP 2001-260310 A

  An object of the present invention is to provide a dampening water treatment method and a dampening water treatment capable of removing impurities that interfere with printing from dampening water and maintaining the original effect of dampening water in offset printing. Is to provide a device. More specifically, the object of the present invention is to selectively remove a phosphorus compound mixed in the fountain solution, and a polyvalent metal such as calcium reacts with the phosphorus compound to form an insoluble salt. Dampening that prevents the precipitation of calcium salts on the image area of the printing plate or on the ink roll of the printing press, and suppresses the deterioration of ink depositing and the occurrence of roller peeling. The object is to provide a water treatment method and a dampening water treatment apparatus.

As a result of intensive research to achieve the above-mentioned problems, the present inventor can maintain the performance of the fountain solution satisfactorily by treating the fountain solution with a filter filled with a specific resin. The inventors have found that good printing can be performed over a long period of time, and have completed the present invention.
Accordingly, the present invention is a treatment method for dampening water used in offset printing, wherein the dampening water is treated using a filter filled with a resin having an acidic group that is salt-exchanged with a divalent or higher cation. This is a method for treating fountain solution.
As an embodiment of the present invention, there is a method for treating dampening water using a resin in which the acidic group is —COO ⁻ or —SO ₃ ^— . Further, there is a dampening water treatment method in which the divalent or higher cation is Fe ³⁺ or Al ³⁺ .

The resin used in the present invention can be prepared by salt exchange of a cation exchange resin having an acidic group with a divalent or higher cation. In a specific embodiment of the present invention, the cation exchange resin having an acidic group subjected to salt exchange with a divalent or higher cation is selected from structural units represented by the following general formulas (I) to (IV). A cation exchange resin having a structural unit is exemplified.

The dampening water treatment method of the present invention specifically includes a resin having an acidic group obtained by salt-exchanging dampening water discharged from a water boat of a continuous water supply type offset printing machine with a divalent or higher cation. Including passing through a filled filter.
More specifically, the dampening water treatment method of the present invention is a method of treating dampening water discharged from a water boat of a continuous water supply type offset printing machine with a cation having a valence of 2 or more through a dampening water circulation tank. It is sent to a dampening water treatment device equipped with a filter filled with a resin having a salt-exchanged acidic group, passed through a filter filled with a resin having an acidic group salt-exchanged with a divalent or higher cation, and passed through the filter. Supplying the fountain solution through the dampening water circulation tank to the water boat of the offset printing press.

The present invention is further directed to a dampening water treatment apparatus used in offset printing. The dampening water treatment apparatus includes a filter cartridge for treating dampening water, and the filter cartridge is a filter cartridge filled with a resin having an acidic group salt-exchanged with a divalent or higher cation. Examples of the resin include the above-described resins.
By treating the dampening water with a filter filled with a resin having an acidic group salt-exchanged with a divalent or higher cation as described above, phosphoric acid, phosphate, phosphonic acid, phosphonic acid in the dampening water Phosphorus compounds such as acid salts can be removed. Since the phosphorus compound in the fountain solution is removed in this way, even if the concentration of calcium in the fountain solution increases, insoluble salts do not precipitate, and roller baldness does not easily occur.

According to the fountain solution treatment method of the present invention, it is possible to sufficiently generate the occurrence of roller flaking and defective inking without depositing an insoluble salt of a phosphorus compound on an ink roll of a printing press or an image area of a printing plate. Can be suppressed.
The dampening water treatment method of the present invention does not affect the basic performance of the dampening water, and does not affect the wettability of the dampening water to the printing plate surface or the hydrophilicity of the printing plate non-image area. According to the fountain solution treated by the fountain solution treatment method of the present invention, during printing, continuous printing can be performed stably without causing problems such as printing plate stains, blinding, water loss, and ink deposit failure. The printability is good.
In addition, according to the dampening water treatment method of the present invention, it is possible to maintain the initial performance without exchanging the dampening water for a long period of time, and even if multiple copies are printed, the non-image area is stained. In this way, a high-quality printed matter can be obtained stably without causing image loss such as skipping of halftone dot highlights, and it is possible to improve printing efficiency and productivity.

Hereinafter, embodiments of the dampening water treatment method and dampening water treatment apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an outline of an embodiment of a dampening water treatment method according to the present invention.
In FIG. 1, reference numeral 20 denotes an offset printing machine, which includes a plate cylinder 21, a water boat 23 for storing dampening water, and a roller 22 for guiding dampening water in the water boat 23 to the plate cylinder 21. Prepare. In the offset printing machine 20, the dampening water in the water boat 23 is guided to the plate cylinder 21 side by the rotation of the roller 22 to wet the non-image area.

  In FIG. 1, a dampening water circulation tank 30 supplies dampening water to the water boat 23 of the offset printing machine 20. The dampening water circulation tank 30 detects the concentration, pH, water temperature and the like of dampening water and alcohol, and replenishes water, replenishes dampening water concentrate and alcohol, etc. Cool dampening water.

  In FIG. 1, 10 is a dampening water treatment apparatus. In the dampening water treatment apparatus 10, reference numeral 1 denotes a suction port, and dampening water used in the offset printing machine 20 is guided through the dampening water circulation tank 30. The pump 2 sucks and discharges dampening water in the apparatus 10. A filter cartridge 4 filled with a resin having an acidic group salt-exchanged with a divalent or higher cation is loaded into the apparatus 10. Reference numeral 5 denotes a pressure detector, which measures a differential pressure upstream and downstream of the filter cartridge. Reference numeral 7 denotes a discharge port, which returns the dampening water treated by the apparatus 10 to the dampening water circulation tank 30.

  As the pump 2 that sucks dampening water from the dampening water circulation tank 30 and circulates the inside of the dampening water treatment apparatus, it is preferable to use a turbine pump or a cascade pump having quantitativeness and pumpability. Moreover, in order not to impair the characteristics of the fountain solution, the above-mentioned pump formed of a corrosion-resistant material is used. Moreover, the pump which has 0.5 Mpa or more as a pumping capability and has the capability of 10 L / min-50 L / min as quantitative property is used. This is to provide a filtering capacity of at least 10 L / min even when the filter is clogged. Furthermore, when the filter is not clogged at all, it passes through the filter at a large flow rate and cannot be properly processed. The purpose is to prevent this.

The resin used in the present invention can be prepared by salt exchange of a cation exchange resin having an acidic group with a divalent or higher cation. As the cation exchange resin having an acidic group that is a precursor of the resin used in the present invention, a gel type cation exchange resin having a low crosslinking degree, a macroporous cation exchange resin having a macro pore, and the like can be used. Known and commercially available cation exchange resins having a diameter of 100 μm to 1000 μm can be used, and both strongly acidic resins and weakly acidic resins can be used.
As said commercially available cation exchange resin used suitably in this invention, the Mitsubishi Chemical Corporation Diaion series is mentioned, for example. Examples of the resin having the structural unit represented by the general formula (I) include Diaion SK1B, SK104, SK116, PK208, PK216, and PK228. Examples of the resin having the structural unit represented by the general formula (II) include Diaion WK10 and WK11, and examples of the resin having the structural unit represented by the general formula (III) include WK20. Moreover, Diaion CR10 is mentioned as resin which has a structural unit represented by general formula (IV).

The divalent or higher cation supported by salt exchange with respect to the above cation exchange resin having an acidic group is preferably a trivalent or higher cation. The divalent or higher cation is not particularly limited, and examples thereof include ions such as Mg, Al, Ca, Zn, Ti, Cr, Fe, Ni, Cu, and Zr. Among these, Fe ³⁺ and Al ³⁺ are particularly preferable from the viewpoints of adsorption capacity and safety of phosphorus compounds.

As a method for supporting a cation exchange resin with a cation having a valence of 2 or more, the cation exchange resin can be easily added to an aqueous solution in which a hydrochloride compound, sulfate compound, nitrate compound, etc. of the cation is dissolved and stirred. Obtainable. The aqueous solution of the divalent or higher cation salt compound preferably has a concentration of 50 to 100 g / L, and it is preferable to add a cation exchange resin in a wet state at a ratio of 100 to 200 g to 1 L of this aqueous solution and stir and mix. It is preferable that the mixing is well stirred for about 10 to 30 minutes at a liquid temperature of 15 to 25 ° C. Further, the loading of a cation having a valence of 2 or more can also be realized by passing an aqueous solution in which a salt compound of a cation having a valence of 2 or more is dissolved through a filter cartridge filled with a cation exchange resin.
The cation exchange resin carrying a divalent or higher cation is prepared by separating with a glass filter or the like and then thoroughly washing with pure water. If the amount of the divalent or higher cation supported is small, the phosphorus compound removal ability cannot be expressed. The amount of divalent or higher cation supported is preferably in the range of 30 to 90 mg, particularly preferably in the range of 50 to 80 mg, per gram of dry mass of the cation exchange resin.
In the present invention, the cation exchange resin carrying the divalent or higher cation obtained as described above, that is, a resin having an acidic group salt-exchanged with a divalent or higher cation is used by filling the filter. Can do.

Next, the operation of the fountain solution treatment apparatus 10 will be described. The dampening water used in the offset printing machine 20 is led from the water boat 23 to the suction port 1 of the dampening water treatment apparatus 10 through the dampening water circulation tank 30. The fountain solution passes through the filter cartridge 4 filled with the resin having an acidic group salt-exchanged with the above-described divalent or higher cation in the fountain solution treatment apparatus 10. This filter cartridge removes phosphorus compounds such as phosphoric acid in the dampening water.
Next, the dampening water processed by the filter cartridge 4 is returned to the dampening water circulation tank 30 from the discharge port 7. Then, the concentration, pH, water temperature and the like of the dampening water and alcohol are adjusted in the dampening water circulation tank 30, and the dampening water is supplied to the offset printing machine 20 again.

Prior to the treatment with the filter cartridge 4 filled with a resin having an acidic group salt-exchanged with a divalent or higher cation, another filter is provided to remove the ink, oil, fine particles of paper powder, etc. from the dampening water. You may go. Such a filter can be disposed upstream of the filter cartridge 4 filled with a resin having an acidic group salt-exchanged with a divalent or higher cation, that is, between the pump 2 and the filter cartridge 4. By removing fine particles such as ink, oil and paper powder from the fountain solution before passing through the resin having an acid group salt-exchanged with a divalent or higher cation, the filter cartridge 4 of the resin can remove these substances. It is preferable that the contamination is suppressed and the life is extended.
FIG. 2 shows an embodiment in which a filter 3 for particulate filtration is loaded between a pump 2 in a fountain solution treatment apparatus 10 and a filter cartridge 4 filled with a resin having an acidic group salt-exchanged with a divalent or higher cation. Represents the form.

Filters used for the purpose of removing fine particles in the fountain solution include a thread-wound filter in which fibers are wound around a porous cylindrical core material over several layers, and an inorganic material such as diatomaceous earth on a nonwoven fabric such as polypropylene fiber. A publicly known or commercially available filter such as a filter using a filter medium formed by blending materials can be used.
If the process is repeated and the filter cartridge 4 becomes clogged, the differential pressure upstream and downstream increases. The pressure detector 5 can measure the differential pressure upstream and downstream of the filter cartridge 4. This differential pressure serves as an index for judging the replacement timing of the filter cartridge.

According to the embodiment described above, since the phosphorus compound is removed by the filter cartridge 4, the fountain solution containing no phosphorus compound can be circulated, and the precipitation of calcium salt on the ink roller can be prevented. The occurrence of roller baldness can be suppressed.
The kind of the fountain solution to which the dampening water treatment method of the present invention is applied is not particularly limited, and for example, a general alcohol-substituting dampening solution or a dampening solution combined with alcohol can be used. Since the method of this invention is the process which removes a phosphorus compound, what does not contain a phosphorus compound in a fountain solution prescription is preferable.

Hereinafter, the present invention will be described in more detail based on examples. In addition, this invention is not limited to the following Example.
[Example 1]
[Production of cation exchange resin carrying Fe ³⁺ ions]
As a cation-exchange resin, an acidic resin comprised cation exchange resin (trade name Diaion SK1B) having a structural unit represented by the general formula (I), poured into an aqueous solution of FeCl _3, stirring, cationic After the Fe ³⁺ ions were saturated and adsorbed on the ion exchange groups of the exchange resin, the cation exchange resin was filtered and separated using a glass filter, and then washed thoroughly with pure water to carry the Fe ³⁺ ions. A cation exchange resin was prepared. Supported amount made by Fe ³⁺ ions carrying Fe ³⁺ ions of the cation exchange resin was dry weight 1g per 70mg of the cation exchange resin.

As an embodiment of the dampening water treatment method, the apparatus and configuration schematically shown in FIG. 2 are employed.
As the dampening water treatment apparatus 10, ECOLI-KIREI100 manufactured by Fuji Film Graphic Systems was used. A filter cartridge 4 filled with a cation exchange resin carrying Fe ³⁺ ions prepared as described above was used. A filter 3 for filtering fine particles was provided on the upstream side of the filter cartridge 4 in order to remove ink, oil, paper powder, powder and the like. As the filter 3 for filtering fine particles, a filtering material in which diatomaceous earth was blended with a nonwoven fabric made of polypropylene was loaded. The pressure detector 6 is a pressure detector for the filter 3 for particulate filtration.
Further, BC713 made by Baldwin was used for the dampening water circulation tank 30.
A printing test was performed by continuous printing while treating the fountain solution with these apparatuses and configurations.

The printing test conditions are shown below.
[Conditions for printing test]
Printing machine: Lithrone 26 2-color machine (manufactured by Komori Corporation)
Printing plate: HPF (Fuji Film)
Paper: Emine (made by Chuetsu Pulp)
Ink: High Unity SOY MZ Red, Indigo (Toyo Ink)
Printing speed: 12,000 sheets / hour Number of printed sheets: 100,000 sheets / day for 5 days

[Observation method of print stains]
The occurrence of print stains on the printed paper surface was observed.
[Observation of defective ink deposition]
The presence or absence of a decrease in the printed matter density of the halftone dot image portion having an image area ratio of 5% or less was observed.
A case where the density of the printed matter at the halftone dots was reduced by 15% or more from the density at the start of printing was regarded as occurrence of defective inking.
[How to observe roller baldness]
Printing was carried out at a water scale 20% higher than the water scale where printing stains were eliminated, and it was observed whether the ink kneading roller was normally attached with ink and no baldness was generated.

  In addition, the dampening water composition prepared by the prescription (unit: gram) described in Table 1 below as the dampening water was diluted 50 times with tap water and used for the printing test. The amount of phosphorus compound in the fountain solution collected after the printing test was measured by an ordinary method using an ICP (Inductively Coupled Plasma) emission analyzer. The results of the printing test and the amount of phosphorus compound are shown in Table 2.

[Example 2]
Performs processing using AlCl ₃ solution with respect the cation exchange resin, except for using Al ³⁺ ion bearing cation exchange resin was supported Al ³⁺ ions, the printing test carried out under the same conditions as in Example 1 It was.
[Example 3]
Performs processing using the ZnCl ₂ solution against cation exchange resin, except for using Zn ²⁺ ion bearing cation exchange resin was supported Zn ²⁺ ions, a printing test conducted under the same conditions as in Example 1 It was.
[Example 4]
It performs processing using the CaCl ₂ aqueous solution with respect to a cation exchange resin, except for using Ca ²⁺ ion bearing cation exchange resin was supported Ca ²⁺ ions was printed test under the same conditions as in Example 1 .

[Example 5]
A printing test was performed under exactly the same conditions as in Example 1 except that a cation exchange resin (trade name: Diaion WK10) having a structural unit represented by the general formula (II) was used as the cation exchange resin.
[Example 6]
A printing test was performed under exactly the same conditions as in Example 1 except that a cation exchange resin having a structural unit represented by the general formula (III) (trade name: Diaion WK20) was used as the cation exchange resin.
[Example 7]
A printing test was performed under exactly the same conditions as in Example 1 except that a cation exchange resin (trade name: Diaion CR10) having a structural unit represented by the general formula (IV) was used as the cation exchange resin.

[Comparative Example 1]
A printing test was performed under exactly the same conditions as in Example 1, except that nothing was filled in the filter cartridge 4 in the fountain solution treatment apparatus 10 and the filter cartridge 4 was used empty.

  From the results in Table 2, even in the fountain solution that does not contain the phosphorus compound in the new solution, elution of the phosphorus compound is observed after the printing test as shown in Comparative Example 1, but the divalent or higher cation is supported according to the present invention. It can be seen that when the fountain solution is treated using a filter filled with the cation exchange resin thus prepared, the concentration of the phosphorus compound is extremely low in any of the examples. In terms of printing performance, no ink burr was generated at all. Also, there was no occurrence of printing stains or ink deposit failure, and there were no problems with other printing performance.

It is the figure showing the outline of one Embodiment of the processing method of the dampening water by this invention. It is the figure showing the outline of another embodiment of the processing method of the dampening water by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Suction port 2 Pump 3 Filter for fine particle filtration 4 Filter cartridge filled with resin having acidic group salt-exchanged with divalent or higher cation 5 Pressure detector 6 Pressure detector 7 Discharge port 10 Dampening water treatment device 20 Offset printing Machine 21 Plate cylinder 22 Roller 23 Water boat 30 Dampening water circulation tank

Claims (6)

  A dampening water treatment method used in offset printing, comprising treating a dampening water with a filter filled with a resin having an acidic group salt-exchanged with a divalent or higher cation. Water treatment method. The method for treating fountain solution according to claim 1, wherein the acidic group is —COO ⁻ or —SO ₃ ^— . The method for treating dampening water according to claim 1 or 2, wherein the divalent or higher cation is Fe ³⁺ or Al ³⁺ . The resin having an acidic group to be subjected to salt exchange is a cation exchange resin having a structural unit selected from structural units represented by the following general formulas (I) to (IV). The processing method of the dampening water of 1 item | term.

  The fountain solution discharged from the water fountain of the continuous water supply type offset printing machine is passed through a filter filled with a resin having an acidic group salt-exchanged with a divalent or higher cation. The dampening water processing method of any one of Claims 1.   A dampening water treatment apparatus used in offset printing, comprising a filter cartridge for treating dampening water, the filter cartridge being filled with a resin having an acidic group salt-exchanged with a divalent or higher cation A dampening water treatment apparatus, characterized by being a filtered cartridge.

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