Treatment method and treatment device for aqueous developing waste liquid, and developing system

Abstract

A treatment method for treating an aqueous developing waste liquid generated by developing a flexographic printing original plate using an aqueous developing liquid, the treatment method comprising: a first filtration step for filtering the aqueous developing waste liquid at 5 DEG C or more and 48 DEG C or less with a fine filtration membrane to obtain a recovered liquid and a concentrated waste liquid; and a reusing step for reusing the recovered liquid for the development of the flexographic printing original plate.

Description

Technical Field

[0001] The invention relates to a method and a device for treating aqueous developing waste liquid, and a developing system. Background Art

[0002] Printing plates with photosensitive resins can be made by computer-to-plate technology (hereinafter referred to as "CTP technology"), which directly draws information processed on a computer into a printing plate shape to produce relief. Among them, flexographic printing, which is a type of relief printing, has the advantage of being applicable to various printed objects because the printing plate uses soft materials such as rubber and synthetic resin.

[0003] The printing plate (especially the flexible printing plate) based on the CTP technology is obtained by the following steps: laser drawing the infrared absorption layer on the photosensitive resin, making the photosensitive resin layer photosensitized and cured, developing the uncured part, and drying the obtained plate while post-exposure. The flexible printing plate can be obtained, for example, by implementing solvent development using a solvent developer to dissolve and develop the uncured part, or aqueous development using an aqueous developer with a surfactant to strip and develop the uncured part. However, if solvent development and aqueous development are implemented, waste liquid of the solution will be generated. CO2 will be generated when the solvent or aqueous developer is manufactured, and when these development waste liquids are treated by incineration. From the perspective of environmental protection, it is desired to reduce the amount of developer used in the development of the printing plate and the amount of development waste liquid generated.

[0004] In solvent development, the solution after development is recovered by distillation and reused. In aqueous development, a method of reusing water recovered by reduced pressure distillation is also disclosed (for example, see Patent Document 1).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2003 / 005129 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] In addition to developer components (such as surfactants), aqueous developer waste liquid also contains impurities mixed into the developer during development, namely developer residues (such as resin in the unexposed portion removed from the developed flexographic printing plate). When the aqueous developer waste liquid is reused, the developer residues need to be removed. Here, the inventors have discovered the following problem: if the aqueous developer waste liquid is filtered using a filter membrane having a pore size larger than the developer components and smaller than the developer residues, it is expected that the developer components can be completely recovered, but in fact the developer components are also removed together (that is, the concentration of the developer is reduced).

[0010] Therefore, an object of the present invention is to improve the recovery rate of developer components when filtering aqueous developer waste liquid and concentrated waste liquid.

[0011] Means used to solve problems

[0012] The present inventors have conducted intensive studies and found that the recovery rate of developer components (eg, surfactant) can be improved by filtering aqueous developer waste liquid and concentrated waste liquid under low temperature conditions.

[0013] The present invention includes the following embodiments. [1]

[0015] A method for treating aqueous development waste liquid generated by developing a flexographic printing plate using an aqueous developer,

[0016] The processing method comprises:

[0017] A first filtering step of filtering the aqueous developing waste liquid at a temperature of 5° C. to 48° C. using a microfiltration membrane to obtain a recovered liquid and a concentrated waste liquid; and

[0018] A recycling step of recycling the recovered liquid for developing a flexographic printing original plate. [2]

[0020] The treatment method according to [1] further includes, before the first filtering step, a temperature adjustment step of adjusting the temperature of the aqueous developer waste liquid to 5° C. or higher and 43° C. or lower. [3]

[0022] The treatment method according to [1] or [2], further comprising: a second filtration step of using the concentrated waste liquid as the aqueous development waste liquid and repeatedly performing the first filtration step. [4]

[0024] The treatment method according to [3], wherein during the second filtration step, the temperature of the concentrated waste liquid is controlled to be 5° C. or higher and 48° C. or lower. [5]

[0026] The processing method according to [3] or [4], wherein:

[0027] The aqueous developing waste liquid contains a surfactant,

[0028] The permeability of the surfactant in the total of the recovered liquid obtained in the first filtration step and the second filtration step is 42% or more and 95% or less. [6]

[0030] The treatment method according to [5], wherein the permeability of the surfactant is 55% or more and 95% or less. [7]

[0032] The processing method according to any one of [3] to [6], wherein during the second filtering step, when the amount of the concentrated waste liquid is lower than a predetermined reference, new aqueous developing waste liquid is added to the concentrated waste liquid. [8]

[0034] The processing method according to any one of [1] to [7], wherein

[0035] When at least one of the following (A) to (F) satisfies the prescribed criteria, the concentrated waste liquid is discarded:

[0036] (A) the total amount of the recovered liquid;

[0037] (B) the number of times the new aqueous developing waste liquid is added to the concentrated waste liquid;

[0038] (C) the total amount of the new aqueous developing waste liquid added to the concentrated waste liquid;

[0039] (D) supply pressure of the aqueous developing waste liquid or the concentrated waste liquid to the filtration membrane;

[0040] (E) an outlet pressure of the aqueous developing waste liquid or the concentrated waste liquid discharged from the filter membrane;

[0041] (F) A circulation flow rate of the aqueous developing waste liquid or the concentrated waste liquid to the filtration membrane. [9]

[0043] The treatment method according to any one of [1] to [8], further comprising: a washing step of washing the filtration membrane with an acidic aqueous solution having a pH of 3 or less.

[10]

[0045] The processing method according to [9], wherein the cleaning step comprises:

[0046] immersing the filter membrane in the acidic aqueous solution; and / or

[0047] The acidic aqueous solution is circulated in the filtration membrane.

[11]

[0049] A processing device for treating aqueous development waste liquid generated by developing a flexographic printing original plate using an aqueous developer, the processing device comprising:

[0050] A water-based developing waste liquid storage tank, which stores the water-based developing waste liquid;

[0051] A filter assembly having a precision filter membrane for filtering aqueous developer waste liquid; and

[0052] A recovery liquid storage tank stores the recovery liquid generated by the filtration.

[12]

[0054] The treatment device according to

[20] further includes a circulation tank for circulating the concentrated waste liquid generated by the filtration in the filtration component.

[13]

[0056] The processing device according to

[21] , wherein the circulation tank has a temperature regulator.

[14]

[0058] A developing system comprising:

[0059] The processing device described in any one of

[11] to

[13] ; and

[0060] A developing device that discharges the aqueous development waste liquid by developing a flexographic printing original plate using an aqueous developer.

[0061] Effects of the Invention

[0062] According to the present invention, it is possible to improve the recovery rate of developer components when filtering aqueous developer waste liquid and concentrated waste liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 A schematic diagram showing a developing system according to one embodiment of the present invention.

[0064] Figure 2 This shows the structure for adjusting the filtration pressure (filtration speed).

[0065] Figure 3 The temperature change of the waste developing liquid over time due to the presence or absence of temperature management is shown. DETAILED DESCRIPTION

[0066] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited thereto and various modifications can be made without departing from the gist of the present invention.

[0067] <Treatment method of aqueous developer waste liquid>

[0068] One embodiment of the present invention relates to a method for treating aqueous development waste liquid generated by developing a flexographic printing original plate using an aqueous developer, comprising:

[0069] A first filtering step of filtering the aqueous developing waste liquid at a temperature of 5° C. or higher and 48° C. or lower using a precision filtration membrane to obtain a recovered liquid and a concentrated waste liquid; and

[0070] In the recycling step, the recovered liquid is recycled for developing the flexographic printing plate.

[0071] In the method of this embodiment, by filtering the aqueous developer waste liquid under low temperature conditions, the amount of developer components removed during filtration can be reduced. As a result, the concentration of developer components contained in the recovered liquid (filtrate) can be maintained, and by reusing the recovered liquid for development, the amount of newly used developer can be reduced. In addition, by reusing the recovered liquid, the amount of waste liquid to be discarded can be reduced. In this way, the method of this embodiment has great advantages in terms of economy and environment.

[0072] [Aqueous developer and aqueous developer waste liquid]

[0073] In this specification, the "aqueous developer" refers to a developer containing water as a solvent.

[0074] In this specification, the "aqueous developing waste liquid" refers to an aqueous developing liquid used in developing.

[0075] In this specification, "concentrated waste liquid" means waste liquid obtained by filtering aqueous developing waste liquid.

[0076] The types of components contained in the aqueous developer (developer components) and the components contained in the aqueous developer waste liquid or concentrated waste liquid are not particularly limited, and examples thereof include surfactants, additives, pH adjusters, and defoamers. In addition to the above components, the aqueous developer waste liquid or concentrated waste liquid also contains impurities mixed into the developer during development, i.e., development residues (e.g., resin in the unexposed portion removed from the developed flexographic printing plate).

[0077] (Surfactant)

[0078] The type of surfactant is not particularly limited, but a nonionic surfactant, anionic surfactant, or a combination thereof is preferred.

[0079] The nonionic surfactant is more preferably a polyalkylene glycol represented by the following formula (B1).

[0080] Formula (B1): RO(AO) p H

[0081] (wherein, R is an alkyl group or an aryl group having 10 to 20 carbon atoms,

[0082] A is an alkylene group having 2 to 4 carbon atoms,

[0083] p is an integer from 1 to 50. )

[0084] In formula (B1),

[0085] R is preferably an alkyl group or an aryl group having 10 to 18 carbon atoms,

[0086] A is preferably an alkylene group having 2 to 4 carbon atoms,

[0087] p is preferably an integer of 6-10.

[0088] The polyalkylene glycol represented by the formula (B1) is preferably a polyoxyalkylene alkyl ether.

[0089] The polyoxyalkylene alkyl ether is preferably a compound represented by the following formula (B1-1) or (B1-2).

[0090] Formula (B1-1): R 4 O(CH2CH2O) p H

[0091] Formula (B1-2): R 4 O(CH2CH2O) p1 (CH(CH3)CH2O) p2 H

[0092] In formula (B1-1), R 4 is an alkyl group having 1 to 20 carbon atoms, and p is an integer from 1 to 50.

[0093] In formula (B1-2), R 4 It is hydrogen or an alkyl group having 1 to 20 carbon atoms, and the total of p1 and p2 is an integer of 1 to 50. -(CH2CH2O) p1 (CH(CH3)CH2O) p2 The -part may be a random polymer or a block polymer.

[0094] As the polyoxyalkylene alkyl ether, a commercially available item can be used. There are no particular restrictions on the commercially available polyoxyalkylene alkyl ether, and examples thereof include Newcol (registered trademark) NT-3, Newcol NT-5, Newcol NT-7, Newcol NT-9, Newcol NT-12, Newcol 2302, Newcol 2303, Newcol 1203, Newcol 1204, Newcol 2303-Y, Newcol 2304-YM, Newcol 2304-Y, polyoxyethylene 2-ethylhexyl ether (Newcol 1004, Newcol 1006, Newcol 1008), polyoxyethylene tridecyl ether (Newcol 1305), Newcol 2306-Y, Newcol 2306-HY, Newcol 2308-Y, Newcol 2308-LY, Newcol 708, Newcol 709, Newcol 82, Newcol 85, Newcol 1210, and Newcol 1902-Y, all manufactured by Nippon Emulsifier Co., Ltd.

[0095] The polyalkylene glycol represented by the formula (B1) is preferably a polyoxyalkylene polycyclic phenyl ether.

[0096] The polyoxyalkylene polycyclic phenyl ether is preferably a compound represented by the following formula (B1-3).

[0097] Formula (B1-3): R 4 O(CH2CH2O) p H

[0098] In formula (B1-3), R 4 is a polycyclic phenyl group, and p is an integer of 1-50.

[0099] As the polyoxyalkylene polycyclic phenyl ether, a commercially available product can be used. There are no particular limitations on the commercially available polyoxyalkylene polycyclic phenyl ether, and examples thereof include Newcol 703, Newcol 704, and Newcol 2604.

[0100] The anionic surfactant is preferably an alkyl ether sulfate, an alkyl sulfate, a fatty acid salt, a linear alkylbenzene sulfonate, or a combination thereof. As the alkyl ether sulfate, for example, sodium polyoxyethylene lauryl ether sulfate (for example, SUNNOL LMT-1430 manufactured by Lion Corporation), polyoxyethylene (C 13 ) sodium alkyl ether sulfate (for example, SUNNOL TD-3130 manufactured by Lion Corporation), alkyl ether sulfate ester salts in which the alkyl group has 8 to 18 carbon atoms (for example, Taycapol NE1230 manufactured by Tayca Corporation).

[0101] The amount of the surfactant contained in the aqueous developer waste liquid is not particularly limited. From the perspective of increasing the development speed, the lower limit is preferably 0.01% by mass, more preferably 0.1% by mass, further preferably 1.0% by mass, and particularly preferably 1.5% by mass. The upper limit is preferably 10% by mass, and more preferably 6.0% by mass. The above lower limit and upper limit can be appropriately combined to define the numerical range. For example, the amount of the surfactant contained in the aqueous developer waste liquid is preferably 0.1-10% by mass, more preferably 1.0-10% by mass, further preferably 1.0-6.0% by mass, and particularly preferably 1.5-6.0% by mass.

[0102] (additive)

[0103] The type of additive is not particularly limited, but a compound represented by the following formula (A1) or formula (A2) is preferred.

[0104] Formula (A1): R 1 O(A 1 O) n R 2

[0105] (Where,

[0106] R 1 and R 2 Each independently represents an alkyl group having 2 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, preferably an alkyl group having 2 to 6 carbon atoms, and more preferably an alkyl group having 4 carbon atoms (butyl group),

[0107] A 1 is an alkylene group having 2 to 4 carbon atoms, preferably an alkylene group having 2 or 3 carbon atoms, and more preferably an alkylene group having 2 carbon atoms (-CH2CH2-),

[0108] n is an integer of 1 to 5, preferably an integer of 1 to 3, and more preferably 2.)

[0109] Formula (A2): R 3 O(A 2 O) m H

[0110] (Where,

[0111] R 3 is an alkyl group having 3 to 8 carbon atoms or an alkenyl group having 3 to 8 carbon atoms, preferably an alkyl group having 3 to 8 carbon atoms, and more preferably an alkyl group having 6 carbon atoms (hexyl group),

[0112] A 2 It is an alkylene group having 2 to 4 carbon atoms, preferably an alkylene group having 2 or 3 carbon atoms, and more preferably an alkylene group having 2 carbon atoms (-CH2CH2-).

[0113] m is an integer of 1 to 5, preferably an integer of 1 to 3, and more preferably 2.)

[0114] The amount of the compound represented by formula (A1) contained in the aqueous developer waste liquid is not particularly limited. From the perspective of increasing the development speed, the lower limit is preferably 0.05% by mass, more preferably 0.15% by mass, and the upper limit is preferably 0.40% by mass, more preferably 0.30% by mass. The above lower limit and upper limit can be appropriately combined to define the numerical range. For example, the amount of the compound represented by formula (A1) contained in the aqueous developer waste liquid is preferably 0.05% by mass or more and 0.40% by mass or less, and more preferably 0.15% by mass or more and 0.30% by mass or less.

[0115] The amount of the compound represented by formula (A2) contained in the aqueous developer waste liquid is not particularly limited. From the viewpoint of increasing the development speed, the lower limit is preferably 0.20% by mass, more preferably 0.25% by mass, and the upper limit is preferably 0.70% by mass, more preferably 0.60% by mass. The above lower limit and upper limit can be appropriately combined to define the numerical range. For example, the amount of the compound represented by formula (A2) contained in the aqueous developer waste liquid is preferably 0.20% by mass or more and 0.70% by mass or less, and more preferably 0.25% by mass or more and 0.60% by mass or less.

[0116] (pH adjuster)

[0117] The type of pH adjuster is not particularly limited, and inorganic bases are preferred. Examples of inorganic bases include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate, cesium bicarbonate, potassium fluoride, sodium fluoride, cesium fluoride, lithium chloride, and lithium bromide.

[0118] The amount of the pH adjuster contained in the aqueous developer waste liquid is not particularly limited, but is preferably contained in an amount such that the pH of the aqueous developer waste liquid becomes 9 or more and 12 or less from the viewpoint of increasing the development speed.

[0119] (Defoaming Agent)

[0120] The type of defoamer is not particularly limited, and examples thereof include organosilicon compounds, and more specifically, compounds containing organic modified silicone, perfluoroalkyl-containing silicone, or fluorine-modified silicone. From the viewpoint of improving dispersibility in an aqueous developer, an emulsion type defoamer is preferably used. Commercially available products of emulsion type defoamers include, for example, KM-73, KM-73A, KM-73E, KM-70, KM-71, KM-75, KM-7750D, KM-85, KM-89, KM-90, KM-98, KM7752, KM-72, KM-72S, KM-72GS, KM-72F, KM-72FS, etc. manufactured by Shin-Etsu Chemical Co., Ltd.

[0121] (Development residue)

[0122] As the resin constituting the photosensitive resin layer of the flexographic printing original plate, for example, a hydrophobic resin, a hydrophilic resin and a combination thereof can be cited. When a hydrophobic resin is used, it is preferred to impart hydrophilicity to the hydrophobic resin. By imparting hydrophilicity to the hydrophobic resin, it is easy to develop the hydrophobic resin using an aqueous developer.

[0123] The main component of the resin constituting the photosensitive resin layer is preferably:

[0124] Resins obtained by modifying hydrophobic resins with carboxylic acids or their salts;

[0125] A mixture of a hydrophobic component mainly composed of a hydrophobic resin and a hydrophilic component mainly composed of a hydrophilic resin;

[0126] A resin formed by chemically bonding a hydrophobic resin to a hydrophilic resin;

[0127] A resin obtained by block copolymerizing a hydrophobic monomer serving as a raw material for a hydrophobic resin and a hydrophilic monomer serving as a raw material for a hydrophilic resin, etc.

[0128] (Other ingredients)

[0129] The aqueous developer, the aqueous developer waste liquid, or the concentrated developer waste liquid may further contain other components such as a viscosity modifier, a stabilizer, and a fragrance.

[0130] [Each step of the treatment method]

[0131] The treatment method of this embodiment preferably includes a temperature adjustment step, a first filtration step, a second filtration step, and a recycling step. Each step will be described below.

[0132] (Temperature adjustment process)

[0133] The temperature adjustment step is a step of adjusting the temperature of the aqueous developer waste liquid to 5° C. or higher and 43° C. or lower before the first filtration step described later.

[0134] From the viewpoint of increasing the development speed, the development of the flexographic printing original is usually carried out in a state where the developer is heated and the temperature of the aqueous developer waste liquid generated by the development also becomes high. In the first filtering step, in order to filter the aqueous developer waste liquid at a low temperature, it is preferred to lower the temperature of the aqueous developer waste liquid in advance through a temperature adjustment step.

[0135] In addition, the aqueous developer waste liquid is actually filtered while circulating in a predetermined device, but the temperature of the circulating aqueous developer waste liquid tends to rise due to the heat source, friction, etc. in the device. Therefore, in the temperature adjustment process, it is preferred to adjust the temperature of the aqueous developer waste liquid to a temperature lower than the temperature required in the first filtering process. Specifically, considering the temperature rise rate of the circulating aqueous developer waste liquid, it is preferred to lower the temperature of the aqueous developer waste liquid to a temperature that is 5°C or more lower than the upper temperature limit (48°C) required in the first filtering process. That is, in the temperature adjustment process, the temperature of the aqueous developer waste liquid is adjusted to be above 5°C and below 43°C, preferably above 5°C and below 35°C, and more preferably above 5°C and below 30°C. The reason for being preferably above 5°C is to prevent the freezing of the aqueous developer waste liquid.

[0136] The method for adjusting the temperature of the aqueous developer waste liquid is not particularly limited, and examples thereof include a method of placing the aqueous developer waste liquid to dissipate heat naturally, a method of performing heat exchange, and a method of direct cooling. From the viewpoint of suppressing power consumption and CO2 emission, the method of placing the aqueous developer waste liquid to dissipate heat naturally is preferred. In the case of placing the aqueous developer waste liquid to dissipate heat naturally, from the viewpoint of avoiding contamination in the circulation tank of the membrane filtration device, it is preferred to set up an aqueous developer waste liquid storage tank for temporarily storing the developer waste liquid.

[0137] (First Filtration Step)

[0138] The first filtration step is a step of filtering the aqueous developer waste liquid at a temperature of 5° C. or higher and 48° C. or lower using a microfiltration membrane (MF membrane) to obtain a recovered liquid and a concentrated waste liquid.

[0139] By filtering the aqueous developer waste liquid under low temperature conditions, the recovery rate of the developer components can be improved. Therefore, the temperature of the aqueous developer waste liquid in the first filtering step is 5°C or higher and 48°C or lower, preferably 5°C or higher and 43°C or lower, and more preferably 5°C or higher and 40°C or lower. By filtering the aqueous developer waste liquid within the above temperature range, the recovery rate of the surfactant can be improved. In addition, the lower limit of the temperature is to prevent the freezing of the aqueous developer waste liquid.

[0140] The first filtration step is preferably carried out in a cross-flow manner using a hollow fiber membrane as the filtration membrane. As commercially available hollow fiber membranes, for example, there can be mentioned Microza (registered trademark) MF modules USW-543 (nominal pore size: 0.1 μm), UMW-553 (nominal pore size: 0.2 μm), USP-343 (nominal pore size: 0.1 μm), UMP-353 (nominal pore size: 0.2 μm), ULW-348 (nominal pore size: 0.45 μm), and UTP-6443 (nominal pore size: 0.2 μm) manufactured by Asahi Kasei Corporation; <Pyuria (registered trademark)> ML MLE-7101(1210) (nominal pore size: 0.1 μm), MLE-7101H(1210) (nominal pore size: 0.1 μm) manufactured by Kuraray Co., Ltd.; Poreflon (registered trademark) modules -01B25 (nominal pore size: 0.08 μm), -11B50 (nominal pore size: 0.08 μm), -11B70 (nominal pore size: 0.08 μm), -11B110 (nominal pore size: 0.08 μm), -02B25 (nominal pore size: 0.1 μm), -12B50 (nominal pore size: 0.1 μm), -12B70 (nominal pore size: 0.1 μm), -12B100 (nominal pore size: 0.1 μm) manufactured by Sumitomo Electric Industries, Ltd. By adopting the cross-flow method, it is possible to suppress the clogging of the membrane during filtration and maintain a high filtration rate (the amount of the recovered liquid obtained per unit time).

[0141] From the viewpoint of obtaining a large amount of recovered liquid, it is preferable that the pressure on the inlet side of the filtration membrane is higher than the pressure on the outlet side. In addition, from the viewpoint of exerting the cross-flow effect, suppressing the clogging of the membrane during filtration, and maintaining a high filtration rate (the amount of the recovered liquid obtained per unit time), the circulation flow rate of the aqueous developing waste liquid to the membrane module during filtration is preferably 1.3 m / second or more.

[0142] (Second filtration step)

[0143] The second filtration step is a step of using the concentrated waste liquid obtained in the first filtration step as the aqueous developing waste liquid and repeatedly carrying out the first filtration step. It should be noted that, for example, in the case where the aqueous developing waste liquid is circulated between the circulation tank 32 and the filtration module 33 in a developing system as shown, the filtration until the same amount of the aqueous developing waste liquid as the aqueous developing waste liquid initially stored in the circulation tank 32 is filtered by the filtration module 33 is called the first filtration step, and thereafter, the filtration until the concentrated waste liquid is discarded is called the second filtration step. Figure 1 As shown, until the concentrated waste liquid is discarded is called the second filtration step.

[0144] In the second filtration step, by repeatedly filtering the concentrated waste liquid, more recovered liquid can be obtained, and the amount of the concentrated waste liquid can be reduced.

[0145] As described above, due to the heat source, friction, etc. in the device, the temperature of the concentrated waste liquid tends to rise during circulation in the device. Therefore, from the viewpoint of improving the recovery rate of the developer components, it is preferred to manage the temperature of the concentrated waste liquid to above 5°C and below 48°C (preferably above 5°C and below 43°C, more preferably above 5°C and below 40°C) during the second filtration step.

[0146] The method of temperature management is not particularly limited. For example, the temperature of the concentrated waste liquid can be directly confirmed and the temperature can be lowered as needed. The method of lowering the temperature is not particularly limited. For example, the method of placing the concentrated waste liquid to allow it to dissipate heat naturally (temporarily interrupting the filtration), the method of performing heat exchange, and the method of direct cooling can be cited. Heat exchange and direct cooling can also be implemented simultaneously with the filtration process. In addition, the temperature of the concentrated waste liquid can also be lowered by adding new aqueous developer waste liquid whose temperature has been lowered in the above-mentioned temperature adjustment process.

[0147] In addition, instead of directly checking the temperature of the concentrated waste liquid, the amount of the concentrated waste liquid may be used as an indirect indicator for temperature management. That is, when the amount of the concentrated waste liquid is lower than a predetermined reference, it is assumed that the circulating concentrated waste liquid exceeds a certain temperature and the temperature of the concentrated waste liquid is lowered.

[0148] In addition, if the amount of concentrated waste liquid decreases, its viscosity increases, and the supply flow rate of the concentrated waste liquid to the filtration membrane slows down. Therefore, the supply flow rate of the concentrated waste liquid can also be used as an indirect indicator for temperature management.

[0149] In addition, when the amount of concentrated waste liquid decreases, its viscosity increases, and the supply pressure of the concentrated waste liquid to the filtration membrane increases. Therefore, the supply pressure of the concentrated waste liquid can also be used as an indirect indicator for temperature management.

[0150] In addition, the "temperature management" of the present invention includes a method of completing the filtration before the temperature of the concentrated waste liquid exceeds the range of the present invention by increasing the filtration speed (the amount of recovered liquid obtained per unit time). That is, the temperature rise of the concentrated waste liquid is roughly proportional to the filtration time, so by shortening the filtration time, the temperature rise of the concentrated waste liquid can be suppressed.

[0151] In addition, for example, "temperature management" in this specification also includes: by sufficiently cooling the temperature of the waste liquid before filtration in the temperature adjustment process, or increasing the filtration speed, or a combination of the two, so as to complete the filtration before the waste liquid temperature exceeds the upper limit. In this case, it is not necessary to interrupt the filtration to implement temperature control such as natural heat dissipation, heat exchange, direct cooling, etc. The method of increasing the filtration speed is described later, and the filtration speed can be adjusted to a sufficient filtration speed before filtration, or the filtration speed can be appropriately adjusted according to the situation during filtration.

[0152] In addition, regarding all the above-mentioned "temperature management" methods, one or more of them can be freely combined and used.

[0153] The transmittance of the surfactant contained in the aqueous developer waste liquid is preferably 34% or more, more preferably 42% or more, and further preferably 55% or more. When the transmittance is 34% or more, the effect of reducing the amount of developer used can be obtained, and when the transmittance is 55% or more, the effect of reducing CO2 emissions can be obtained. In addition, the so-called CO2 reduction refers to a state in which the CO2 reduction amount achieved by reusing the recovered liquid (i.e., the reduction in the amount of developer used and the reduction in the amount of developer waste liquid discharged) is compared with the CO2 emissions associated with the amount of electricity consumed in the implementation of the method of this embodiment (the CO2 emissions generated during power generation), and the CO2 reduction amount exceeds the CO2 emissions.

[0154] The permeability of the surfactant is preferably 95% or less, more preferably 90% or less. If the permeability is 95% or less, the concentrated waste liquid obtained after filtration also contains sufficient surfactant, so the aggregation of resin in the concentrated waste liquid can be suppressed, avoiding failure of the membrane filtration device.

[0155] The permeability of the surfactant is preferably 42% to 95%, more preferably 55% to 95%, and even more preferably 55% to 90%.

[0156] The permeability of the surfactant was calculated by the following formula.

[0157] Transmittance = [Concentration of surfactant in recovery liquid / Concentration of surfactant in development waste liquid] × 100

[0158] The transmittance is calculated based on the total recovery liquid obtained from the start of the first filtering step to the end of the second filtering step (i.e., the multiple recovery liquids obtained in the first filtering step and the second filtering step are combined). In this case, the transmittance becomes: the ratio of the concentration of the surfactant in the total recovery liquid obtained from the start of the first filtering step to the end of the second filtering step to the concentration of the surfactant in the developer waste liquid before filtration in the first filtering step.

[0159] The transmittance is not only affected by the temperature of the developer waste liquid, but also by the clogging of the filter membrane, etc. That is, if the clogging of the filter membrane becomes larger, there is a tendency for the transmittance to decrease. Therefore, when the transmittance is lower than the above lower limit, it is preferred to implement the cleaning process described later to maintain the transmittance within the desired range.

[0160] On the other hand, in the membrane filtration method, the filtration speed is usually not increased. This is because, even in the case of a cross-flow method, if the filtration speed is too high, the clogging of the membrane by the developer residue will also increase, and as a result, the filtration speed will significantly decrease over time, and it will become impossible to use repeatedly. In addition, if the clogging of the membrane increases, the clogged developer residue will capture the developer components such as surfactants, thereby gradually reducing the transmittance of the developer components in the filtration process. As a result, when the recovery liquid is reused, a large amount of additional developer is required to adjust the concentration. That is, since the high filtration speed is in a trade-off relationship with the life of the hollow fiber membrane and the transmittance of the developer components, a method of suppressing the filtration speed is usually adopted by throttling the piping of the recovery liquid using a valve (filter valve).

[0161] The inventor invented a hollow fiber membrane cleaning technology in order to take into account high filtration speed, life of the hollow fiber membrane (blockage suppression) and transmittance of the developer component. If the cleaning method of the present invention is implemented, the hollow fiber membrane will not be blocked even if the aqueous developer waste liquid and the concentrated waste liquid are filtered at a high filtration speed, and can be repeatedly used while maintaining the high filtration speed and transmittance of the developer component. In this way, the temperature rise of the concentrated waste liquid during filtration can be suppressed, and the recovery efficiency of the developer component can be improved.

[0162] As a method for increasing the filtration speed, for example, a method of increasing the pressure (filtration pressure) of the aqueous developer waste liquid or concentrated waste liquid applied to the hollow fiber membrane can be cited (the specific adjustment method is described later). In fact, a mechanical upper limit is set for the filtration pressure and each pressure value related to the filtration pressure according to the material and shape of the membrane assembly used, so it is adjusted to be below the upper limit. As a method for suppressing clogging and maintaining a high filtration speed, in addition to the cleaning method of the hollow fiber membrane described later, the application method in the filtration process can also be studied.

[0163] As the concentrated waste liquid is repeatedly filtered in the second filtering step, the concentration of the developer residue contained in the concentrated waste liquid gradually increases, which is likely to cause clogging of the filter membrane. Therefore, it is preferred to discard the concentrated waste liquid at a predetermined time (to end the filtering step). For example, the concentrated waste liquid can be discarded when at least one of the following (A) to (F) meets the predetermined criteria.

[0164] (A) the total amount of recovered liquid,

[0165] (B) the number of times new aqueous developing waste liquid is added to the concentrated waste liquid,

[0166] (C) the total amount of new aqueous developing waste liquid added to the concentrated waste liquid,

[0167] (D) the supply pressure of the aqueous developing waste liquid or concentrated waste liquid to the filter membrane,

[0168] (E) the outlet pressure of the aqueous developing waste liquid or the concentrated waste liquid discharged from the filter membrane,

[0169] (F) Circulation flow rate of aqueous developer waste liquid or concentrated waste liquid to the filter membrane (L / min)

[0170] For example, by using the values ​​of (A) and (B) or (C), the concentration ratio to be achieved can be calculated, so the filtration process can be terminated at the target concentration ratio. In addition, when the viscosity of the concentrated waste liquid increases significantly beyond expectations due to some reason, the supply pressure (D) of the concentrated waste liquid to the filter membrane increases, the outlet pressure (E) of the filter membrane decreases, and the circulation flow rate (F) decreases before the target concentration ratio is reached. Therefore, by monitoring these and completing the filtration process when the prescribed benchmark is met, the filtration process can be terminated without excessively loading the filter membrane, and clogging can be suppressed.

[0171] When performing such an operation, it is preferred to use a system that monitors at least one of the above (A) to (F) (for example, only A, A+B, A+C, only D, only E, only F, or any combination of D to F) to determine whether the specified criteria are met.

[0172] According to the present invention, by filtering the aqueous developer waste liquid or concentrated waste liquid at a low temperature, the recovery efficiency (transmittance) of the developer components (such as surfactants) can be improved. The aqueous developer waste liquid discharged from the developing device is at a high temperature, so the filtration process can be started after cooling. As a temperature management method during filtration, at least one of the above methods can be adopted, or a combination of multiple methods can be implemented. By increasing the filtration speed, the filtration time can be shortened, and the temperature rise of the concentrated waste liquid can be suppressed. The filter membrane is clogged by developer residues due to increased filtration speed and repeated use, and the filtration speed is reduced. However, by adopting the cleaning method of the filter membrane of the present invention and the stopping method of the above filtration process, the clogging can be prevented from being aggravated, and the filter membrane can be repeatedly used at a high filtration speed. The filtration speed is not particularly limited, and is preferably 8.5L / hr·m 2 More preferably, 10 L / hr·m 2 More preferably, 11.5 L / hr·m 2 In addition, from the viewpoint of monitoring the concentration ratio reached, each pressure gauge, the circulation flow rate of the concentrated waste liquid, etc. and completing the concentration at an appropriate time, the upper limit of the filtration rate is preferably 50 L / hr·m 2 Below, more preferably 45L / hr·m 2 Below. L / hr·m 2 It is defined by the amount of recovered liquid obtained per unit area of ​​the hollow fiber membrane and per unit time of filtration.

[0173] (Recycling process)

[0174] The recycling step is a step of recycling the recovered liquid obtained in the first filtration step and / or the second filtration step for developing the flexographic printing original plate.

[0175] The concentration of the developer component contained in the recovery liquid is lower than that of the aqueous developer. Therefore, when the recovery liquid is reused for development, it is preferred to add the developer component (for example, at least one component selected from the group consisting of water, surfactants, additives and pH adjusters).

[0176] The added developer component (for example, at least one component selected from the group consisting of water, surfactants, additives and pH adjusters) may be directly added to the recovery liquid or added to the aqueous developer mixed with the recovery liquid.

[0177] (Cleaning process)

[0178] The washing step is a step of washing the filtration membrane with an acidic aqueous solution having a pH of 3 or less.

[0179] By performing the first filtering step and the second filtering step, the developing residue adheres to the filter membrane and causes clogging, so the filtering speed is reduced, so it is preferred to clean the filter membrane. The cleaning step is preferably carried out after the second filtering step is completed as needed. However, the frequency and interval of cleaning are not particularly limited, and for example, the cleaning step can be carried out when the filtering speed is observed to be reduced.

[0180] From the viewpoint of removing the developer residue, the pH of the acidic aqueous solution is 3 or less, preferably 2.5 or less, and more preferably 2 or less. When the pH is 3 or less, the absolute value of the zeta potential of the developer residue particles attached to the filter membrane becomes larger, the particles repel each other and the particle size becomes smaller, thereby the particles are removed and the clogging is eliminated.

[0181] The type of acid contained in the acidic aqueous solution is not particularly limited, and examples thereof include inorganic acids (eg, phosphoric acid, nitric acid, hydrochloric acid, sulfuric acid), organic acids (eg, acetic acid, formic acid, citric acid, oxalic acid), and mixed acids thereof.

[0182] The washing method is not particularly limited, and examples thereof include a method of immersing the filtration membrane in an acidic aqueous solution and a method of circulating the acidic aqueous solution through the filtration membrane.

[0183] In the cleaning process, the filter membrane can be backwashed with the recovery liquid. Backwashing means that the recovery liquid is made to flow in the direction opposite to the flow direction of the aqueous developer waste liquid or concentrated waste liquid in the first and second filtering processes to remove the developer residue attached to the filter membrane. In addition, backwashing can also be implemented during filtration. For example, the recovery liquid obtained can be used for backwashing in a state where the circulation of the concentrated waste liquid is temporarily stopped (the first and second filtering processes are stopped). At this time, the time interval between filtration / backwashing can be freely determined. For example, 10 minutes of filtration / 10 seconds of backwashing can be used as a cycle and the cycle can be repeated.

[0184] <Aqueous developer waste liquid treatment device and developer system>

[0185] One embodiment of the present invention relates to a treatment device for aqueous development waste liquid generated by developing a flexographic printing original plate using an aqueous developer, the treatment device comprising:

[0186] A water-based developing waste liquid storage tank, which stores the water-based developing waste liquid;

[0187] a filter assembly having a precision filter membrane for filtering the aqueous developer waste liquid; and

[0188] The recovery liquid storage tank stores the recovery liquid generated by the filtration.

[0189] The treatment device may further include a circulation tank for circulating the concentrated waste liquid produced by filtration in the filtration assembly. The circulation tank may also have a temperature regulator.

[0190] The water-based waste developer storage tank may have a temperature regulator. If the water-based waste developer storage tank does not have a temperature regulator, the water-based waste developer may be placed in the water-based waste developer storage tank to dissipate heat naturally to lower the temperature of the water-based waste developer.

[0191] One embodiment of the present invention relates to a developing system including the above-mentioned processing device and a developing device that discharges aqueous development waste liquid by developing a flexographic printing original plate using an aqueous developer.

[0192] Hereinafter, a processing apparatus and a developing system according to an embodiment of the present invention will be described with reference to the drawings, but the configurations of the processing apparatus and the developing system are not limited thereto.

[0193] Figure 1 1 shows a developing system 1. The developing system 1 includes a developing device 2 and a processing device 3.

[0194] The developing device 2 includes a developer tank 21 storing an aqueous developer and a brush 5 for rubbing the surface of the flexographic printing plate 4 .

[0195] In the developing device 2, the aqueous developer stored in the developer tank 21 is supplied to the flexible printing original plate 4 via the return pipe 210, and the surface of the flexible printing original plate 4 is rubbed by the brush 5. The development residue removed from the flexible printing original plate 4 is returned to the developer tank 21 together with the aqueous developer. Whenever a new flexible printing original plate is developed, the aqueous developer is supplied to the developer tank 21 via the delivery pipe 6 as needed, and the aqueous developer (aqueous developer waste liquid) exceeding the prescribed amount is delivered from the developer tank 21 to the aqueous developer waste liquid storage tank 31 via the delivery pipe 221.

[0196] The treatment device 3 includes: an aqueous waste developing liquid storage tank 31 for storing aqueous waste developing liquid; a filter module 33 having a precision filter membrane for filtering the aqueous waste developing liquid; and a recovery liquid storage tank 35 for storing recovery liquid generated by filtration. The details of the filter membrane are as described in the above (first filtering step) column.

[0197] The treatment device 3 may further include a circulation tank 32 for circulating the concentrated waste liquid in the filtering assembly 33 .

[0198] The processing device 3 may further include a filtrate tank 34 , which returns the recovered liquid generated by the filtration to the filtration component 33 or sends it to the recovered liquid storage tank 35 .

[0199] The processing device 3 may further include a concentrated waste liquid storage tank 36 for storing discarded concentrated waste liquid.

[0200] The processing device 3 may further include a temperature regulator 37 for regulating (lowering) the temperature of the aqueous waste developer stored in the aqueous waste developer storage tank 31. The processing device 3 may further include a temperature regulator 38 for regulating (lowering) the temperature of the concentrated waste liquid stored in the circulation tank 32. The type of the temperature regulator is not particularly limited, and examples thereof include a heat exchanger, a direct cooler, and a heat pump.

[0201] In the processing device 3, the aqueous developer waste liquid stored in the aqueous developer waste liquid storage tank 31 is temperature-controlled as needed and then sent to the circulation tank 32 via the sending pipe 311. The aqueous developer waste liquid stored in the circulation tank 32 is sent to the filter unit 33 via the sending pipe 321 and filtered.

[0202] In the filter assembly 33, recovered liquid and concentrated waste liquid are obtained, and the concentrated waste liquid is returned to the circulation tank 32 via the return pipe 330. The concentrated waste liquid returned to the circulation tank 32 is sent to the filter assembly 33 again via the delivery pipe 321, and circulates between the circulation tank 32 and the filter assembly 33. After the concentrated waste liquid is repeatedly circulated between the circulation tank 32 and the filter assembly 33, the concentrated waste liquid is sent to the concentrated waste liquid storage tank 36 via the delivery pipe 322.

[0203] By providing the processing device 3 with the aqueous waste developer storage tank 31, it is possible to avoid storing the aqueous waste developer for a long time in the entire processing device 3, and to avoid contamination in the processing device 3. The processing device 3 may include two or more (preferably two) aqueous waste developer storage tanks 31. With such a configuration, while filtering the temperature-regulated aqueous waste developer stored in one aqueous waste developer storage tank 31, the temperature of the aqueous waste developer can be regulated in another aqueous waste developer storage tank 31, so that efficient operation can be performed.

[0204] The circulation tank 32 may also have a liquid level meter (not shown). The amount of concentrated waste liquid in the circulation tank 32 is measured by the liquid level meter. When the amount is lower than a predetermined reference, new aqueous waste liquid can be supplied from the aqueous waste liquid storage tank 31 to the circulation tank 32 to reduce the temperature of the concentrated waste liquid. For example, when 200 L of aqueous waste liquid is filtered and concentrated (4 times concentrated) to 50 L, 100 L of aqueous waste liquid can be supplied to the circulation tank 32 at the beginning of filtration and then filtration can be started. When the amount of liquid in the circulation tank 32 is lower than a predetermined reference, the remaining 100 L of aqueous waste liquid can be supplied to the circulation tank 32 once or in multiple times.

[0205] The delivery pipe 321 and / or the return pipe 330 may have a pressure gauge (not shown). The pressure of the concentrated waste liquid passing through the delivery pipe 321 and / or the return pipe 330 may be measured. When the prescribed benchmark is met, it is assumed that the concentrated waste liquid is sufficiently concentrated (or the waste liquid viscosity exceeds the benchmark), the filtration process is completed, and the concentrated waste liquid is delivered to the concentrated waste liquid storage tank 36. In addition, the delivery pipe 321 and / or the return pipe 330 may also have a flow meter (not shown). The flow rate [L / min] of the concentrated waste liquid passing through the delivery pipe 321 and / or the return pipe 330 may be measured. When the prescribed benchmark is met (lower than the prescribed benchmark), it is assumed that the concentrated waste liquid is sufficiently concentrated (or the waste liquid viscosity exceeds the benchmark), the filtration process is completed, and the concentrated waste liquid is delivered to the concentrated waste liquid storage tank 36.

[0206] The recovered liquid obtained by the filter element 33 is sent to the filtrate tank 34 via the delivery pipe 331. The recovered liquid stored in the filtrate tank 34 is returned to the filter element 33 via the return pipe 340 as needed to clean (backwash) the filter element 33. In addition, the recovered liquid stored in the filtrate tank 34 is sent to the recovered liquid storage tank 35 via the delivery pipe 341.

[0207] In addition, if Figure 2As shown, the delivery pipe 321 may also have a pressure gauge 8A and a valve 9A. The return pipe 330 may also have a pressure gauge 8B and a valve 9B. The delivery pipe 331 may also have a pressure gauge 8C and a valve 9C. Here, if the supply pressure of the concentrated waste liquid to the filter assembly 33 is set to Pi (the pressure measured by the pressure gauge 8A), the outlet pressure is set to Po (the pressure measured by the pressure gauge 8B), and the discharge pressure of the recovery liquid is set to Pf (the pressure measured by the pressure gauge 8C), the filtration pressure is described as {(Pi+Po) / 2}-Pf.

[0208] For example, by opening valve 9C, Pf decreases, and the filtration pressure can be increased, and the filtration speed can be increased. In addition, by opening valve 9A, Pi rises, and the filtration pressure can be increased, and the filtration speed can be increased. And then, by closing valve 9B, Po rises, and the filtration pressure can be increased, and the filtration speed can be increased. The preferred filtration pressure is more than 0.03MPa, and more preferably more than 0.04MPa. In addition, from the viewpoint of reducing the physical load on the membrane and avoiding failure, the filtration pressure is preferably less than 0.5MPa, and more preferably less than 0.4MPa. As described above, by increasing the filtration speed, the filtration can be completed before the temperature of the concentrated waste liquid exceeds the specified benchmark.

[0209] The recovery liquid stored in the recovery liquid storage tank 35 is fed to the developing device 2 through the feeding pipe 351 to be reused after the developer component is added as needed.

[0210] Example

[0211] Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples, but the technical scope of the present invention is not limited thereto.

[0212] The apparatus used in Examples and Comparative Examples are as follows.

[0213] ·Developing device: AWP manufactured by Asahi Kasei Corporation TM -DEW4260 PLF

[0214] Filter element: Asahi Kasei Microza MF element UMP-153 (nominal pore size: 0.2 μm) or UMP-353 (nominal pore size: 0.2 μm)

[0215] The aqueous developer used in Examples and Comparative Examples contained the following components.

[0216] Developer A

[0217] Solvent (water)

[0218] Surfactant (trade name: Newcol NT-7, manufactured by Nippon Emulsifier Co., Ltd.)

[0219] Surfactant (trade name: Newcol NT-9, manufactured by Nippon Emulsifier Co., Ltd.)

[0220] Additives (Diethylene glycol dibutyl ether (DBDG))

[0221] Additives (Diethylene glycol monohexyl ether (HeDG))

[0222] pH adjuster (potassium carbonate)

[0223] Developer B

[0224] Solvent (water)

[0225] Surfactant (trade name: SUNNOL LMT-1430, manufactured by LION Corporation)

[0226] The cleaning agents (commercial products) used in Examples and Comparative Examples are as follows.

[0227] ULTRASIL75 manufactured by ECOLAB

[0228] ULTRASIL MP manufactured by ECOLAB

[0229] ULTRASIL115 manufactured by ECOLAB

[0230] <Recovery Test 1>

[0231] The aqueous developer waste liquid used in the examples and comparative examples was used to prepare the flexographic printing original (AWP) by using a developing device containing aqueous developer A. TM -DEW (1.14 mm, BL size)) was developed to obtain a total of 119 plates. Table 1 shows the concentrations of components contained in the aqueous developer waste liquid.

[0232] [Example 1]

[0233] The aqueous developer waste liquid was adjusted to 20°C, and cross-flow filtration was repeatedly performed using the filter assembly UMP-153 (implementing the above-mentioned first filtration step and second filtration step) to obtain 80% of the volume of the aqueous developer waste liquid (16L of recovered liquid and 4L of concentrated waste liquid were obtained from 20L of aqueous developer waste liquid). At this time, the supply pressure Pi of the aqueous developer waste liquid was 0.06Mpa, the outlet pressure Po was 0.04Mpa, the discharge pressure Pf was 0.01Mpa, and the circulation flow rate of the aqueous developer waste liquid was 2m / sec. The concentration, recovery rate and transmittance of the components contained in the recovered liquid are shown in Tables 1 to 3. It should be noted that the recovery rate refers to the ratio of the mass of each component contained in the recovered liquid based on the mass of each component contained in the aqueous developer waste liquid. The transmittance refers to the ratio of the concentration of each component contained in the recovered liquid based on the concentration of each component contained in the aqueous developer waste liquid. The concentration of each component was measured by sampling the aqueous developer waste liquid from the waste liquid before filtration and sampling the recovered liquid from the liquid obtained by mixing all the liquids obtained by the above filtration (the first filtration step and the second filtration step).

[0234] First, for DBDG and HeDG as additives, a membrane filter with a pore size of 0.8 μm (25CS080 AN manufactured by ADVANTEC Toyo Co., Ltd.) was used to remove the developer residue and the like to obtain a clear solution, and then the concentration was obtained by quantitative analysis by gas chromatography. In addition, for the surfactant, the developer waste liquid was weighed before and after being dried to obtain the non-volatile component, and the mass percentage concentration of the surfactant was determined. Specifically, a certain amount of developer waste liquid was first taken, filtered using a membrane filter with a pore size of 0.8 μm (25CS080AN manufactured by ADVANTEC Toyo Co., Ltd.), and after removing the developer residue, the weight W1 was measured. Next, the developer waste liquid was dried in a constant temperature tank at 40°C, and the weight W2 of the non-volatile component was measured, and (W2 / W1)×100 was calculated. For the development waste liquid and recovered liquid obtained using developer B, this value was taken as the surfactant concentration. For the development waste liquid and recovered liquid obtained using developer A, the value obtained by subtracting the DBDG and HeDG concentrations measured by the above method was taken as the surfactant concentration.

[0235] [Example 2]

[0236] The aqueous developer waste liquid was adjusted to 40°C, and other filtering conditions were set in the same manner as in Example 1. The filter assembly was used to filter and obtain 80% by volume of the aqueous developer waste liquid. The concentrations, recovery rates, and transmittances of the components contained in the recovered liquid are shown in Tables 1 to 3.

[0237] [Comparative Example 1]

[0238] The aqueous developer waste liquid was adjusted to 50° C. and filtered using a filter assembly to obtain a recovery liquid of 80% by volume of the aqueous developer waste liquid. The concentrations, recovery rates, and transmittances of the components contained in the recovery liquid are shown in Tables 1 to 3.

[0239] [Table 1]

[0240]

[0241] [Table 2]

[0242]

[0243] [Table 3]

[0244]

[0245] According to the results in Table 2, it is found that there is no problem in treating the relationship between temperature and recovery rate as a linear model. The temperature of the aqueous developer waste liquid is used as the explanatory variable X, and the recovery rate is used as the target variable Y. The linear regression equation is obtained, and the following mathematical formula is obtained.

[0246] Surfactant: Y = -0.6131X + 56.676

[0247] HeDG:Y=-0.5595X+65.92

[0248] DBDG:Y=-0.6755X+64.175

[0249] From the obtained mathematical formula, it can be seen that the total recovery rate of surfactants and additives (HeDG, DBDG) becomes 27% or more when the temperature of the aqueous developer waste liquid is below 48°C. In addition, it can be seen that the preferred recovery rate, i.e., 30% or more, is below 43°C, and the more preferred recovery rate, i.e., 32% or more, is below 40°C.

[0250] <Recovery Test 2>

[0251] The aqueous developer waste liquid used in the examples and comparative examples was prepared by using a developing device to which an aqueous developer B was added to form a flexographic printing original (AWP). TM -DEW (1.14 mm, BL size)) was developed for a total of 34 plates. Table 4 shows the concentrations of components contained in the aqueous developer waste liquid.

[0252] [Example 3]

[0253] The aqueous developer waste liquid was adjusted to 15°C, and cross-flow filtration was repeatedly performed using a filtration assembly (UMP-153) (implementing the first filtration step and the second filtration step described above) to obtain 80% of the aqueous developer waste liquid as a recovery liquid (16L of recovery liquid and 4L of concentrated waste liquid were obtained from 20L of aqueous developer waste liquid). At this time, the supply pressure Pi of the aqueous developer waste liquid was 0.06Mpa, the outlet pressure Po was 0.04Mpa, the discharge pressure Pf was 0.01Mpa, and the circulation flow rate of the aqueous developer waste liquid was 2m / sec. The concentration, recovery rate, and transmittance of the components contained in the recovery liquid are shown in Tables 4 to 6.

[0254] [Example 4]

[0255] The aqueous developer waste liquid was adjusted to 28°C, and other filtering conditions were set in the same manner as in Example 3. The filter assembly was used to filter and obtain 80% by volume of the aqueous developer waste liquid. The concentrations, recovery rates, and transmittances of the components contained in the recovered liquid are shown in Tables 4 to 6.

[0256] [Example 5]

[0257] The aqueous developer waste liquid was adjusted to 48°C and filtered using a filter assembly to obtain a recovery liquid of 80% by volume of the aqueous developer waste liquid. The concentrations, recovery rates, and transmittances of the components contained in the recovery liquid are shown in Tables 4 to 6.

[0258] [Table 4]

[0259]

[0260] [Table 5]

[0261]

[0262] [Table 6]

[0263]

[0264] <Temperature Management of Wastewater>

[0265] Next, in the tank of the developing device, the developer A was adjusted in temperature within the range of 40°C to 45°C while the flexographic printing original plate (AWP) was heated. T -DEW (1.14mm, BL size)) was used to develop a total of 125 plates. The temperature change when the developing waste liquid (120L) was cross-flow filtered using a filter assembly (UMP-353 (nominal pore size: 0.2μm) under the following conditions was confirmed. At this time, the supply pressure Pi of the aqueous developing waste liquid was 0.09Mpa, the outlet pressure Po was 0.01Mpa, the discharge pressure Pf was 0.03Mpa, and the circulation flow rate of the aqueous developing waste liquid was 2m / sec. The results are shown in Figure 3 .like Figure 3 As shown, if the temperature of the developer waste liquid is not managed, the temperature rises over time and exceeds 48°C.

[0266] (Condition A)

[0267] No temperature management (the aqueous developing waste liquid A discharged from the developing device is immediately subjected to cross-flow filtration).

[0268] (Condition B)

[0269] The aqueous developing waste liquid A discharged from the developing device was immediately subjected to cross-flow filtration. When the waste liquid temperature reached 46°C, the filtration was interrupted, and when the waste liquid temperature dropped to 43°C, the filtration was resumed.

[0270] (Condition C)

[0271] Reduce the wastewater temperature before starting filtration.

[0272] (condition D)

[0273] The waste liquid temperature was lowered before the start of filtration, and new waste liquid (20 L) of the lowered temperature was added every time 20 L of recovered liquid was obtained.

[0274] <Recycling of Development Wastewater>

[0275] The evaluation results of the reuse of the recovered liquid (75% of the recovered waste liquid) obtained by cross-flow filtration using the filter unit UMP-353 (nominal pore size: 0.2 μm) with various changes in temperature for the same developer waste liquid A and B used in the above-mentioned recovery experiment 1 and recovery experiment 2 are shown in Tables 7 and 8. During the filtration, the supply pressure Pi of the aqueous developer waste liquid was 0.09 MPa, the outlet pressure Po was 0.01 MPa, the discharge pressure Pf was 0.03 MPa, and the circulation flow rate of the aqueous developer waste liquid was 2 m / sec. In the example shown in the table where "temperature management" is "yes", it means that any one or more combinations of natural cooling of the waste liquid before the start of filtration, adjustment of the filtration speed, addition of waste liquid during the filtration process, and use of a temperature control device (set in the circulation tank 32) are implemented. In the example where "temperature management" is "no", the high-temperature waste liquid discharged from the developer is immediately subjected to cross-flow filtration, and the above-mentioned temperature management is not implemented during the filtration. The developer waste liquid is collected from the circulation tank 32 before the filtration begins, and the recovered liquid is collected from the filtrate tank 34 after the filtration is completed. The surfactant concentration is measured and the transmittance is calculated. In order to avoid clogging of the filter assembly due to over-concentration, the amount of developer waste liquid supplied to the circulation tank 32 and the total amount of recovered recovered liquid are monitored during the filtration. When the concentration ratio reaches 4 times (75% of the waste liquid is recovered), the filtration process is terminated and the concentrated waste liquid is discharged. In addition, the supply pressure Pi of the concentrated waste liquid to the filter assembly is monitored during the filtration, and it is operated in a manner not exceeding 0.15Mpa (an interlock is set to terminate the filtration if it exceeds). After adding surfactants and water to the recovered liquid to adjust the concentration, it is returned to the developing device for the development test.

[0276] "Development residue separation" indicates whether the development waste liquid can be filtered. "A" indicates that the development waste liquid can be filtered. "B" indicates that the development waste liquid cannot be filtered.

[0277] "Developer addition amount" indicates the amount of surfactant that needs to be added to the recovery liquid in order to perform development with the recovery liquid. It is defined as the ratio of the amount of surfactant added to the recovery liquid to the amount of surfactant contained in the commonly used new developer (referring to the usual developer without recovery liquid and the new liquid that has not been used for development. It refers to the new developers A and B before development in recovery experiments 1 and 2). For example, the surfactant (the total of NT-7 and NT-9, the ratio is 1:1) in 200L of the new developer A before development is 8kg (concentration: 4%). On the other hand, when 2kg of surfactant (the total of NT-7 and NT-9, the ratio is 1:1) is added to the obtained recovery liquid 160L, it is marked as 2×100 / 8=25%. After adding the surfactant, water is added in such a way that the volume of the recovery liquid becomes 200L, and then the development test is carried out. In the development test, the back of the flexible printed original plate is first exposed to cure the substrate, so that the thickness of the resin in the uncured part is 0.6 mm (relief depth). Then, the development test is carried out with the appropriate development time of the above-mentioned new developer (development time with a relief depth of 0.6 mm), and a visual inspection of the plate surface is carried out to confirm whether there are bumps (development residue). The test is carried out in the order of additional amounts of surfactant 25%, 35%, and 45%. If there are no bumps above 25%, it is recorded as "25%", if there are no bumps above 35%, it is recorded as "35%", and if there are no bumps at 45%, it is recorded as "45%". If bumps are observed even if the proportion of the additional surfactant is 45%, it is recorded as "B", and it is judged that the effect of reducing the amount of developer used cannot be obtained.

[0278] "CFP" indicates the presence or absence of a CO2 reduction effect. "A" indicates a CO2 reduction effect. "B" indicates no CO2 reduction effect. It should be noted that the presence or absence of a CO2 reduction effect is estimated by taking into account the power consumed by the operation of the filtration device, the amount of developer used, and the amount of reduction in developer waste liquid. Regarding power consumption and developer use, the CO2 emission coefficient was calculated based on the IDEA database provided by the Institute of Advanced Industrial Science and Technology. In addition, for the disposal of developer waste liquid, the CO2 emission is calculated assuming that the substances contained in the developer waste liquid are completely burned.

[0279] It is known that by suppressing the clogging of the membrane module and managing the waste liquid temperature of the first and second filtration steps to be 5°C or more and 48°C or less, it is possible to separate the developer residue and reuse the recovered liquid (reduced developer usage). In particular, when the transmittance is 42% or more and 95% or less, the developer usage can be reduced by 65%, which is preferred. Furthermore, when the transmittance is 55% or more, the developer usage can be reduced by 75%, and a CO2 reduction effect can also be obtained, which is more preferred.

[0280] [Table 7]

[0281]

[0282] [Table 8]

[0283]

[0284] <Cleaning Test 1>

[0285] ULTRASIL 75 and ULTRASIL MP were diluted in stages to prepare a cleaning solution. The cleaning solution was filled into a filter assembly (UMP-153) that had been filtered 26 times of aqueous developer waste liquid (a total of about 520 L of filtration). After standing for 3 days, the inner surface of the hollow fiber membrane was observed using a SEM. The VHX-D510 manufactured by KEYENCE was used, the acceleration voltage was set to 5 kV, and the secondary electron image was observed (magnification: 5000 times). As shown in Table 9, the cleaning result depends on the pH of the cleaning solution. When the pH is below 2.9, the developer residue can be removed and the filtration speed is restored. In contrast, when the pH is 3.7, the developer residue cannot be removed.

[0286] In addition, when alkaline ULTRASIL115 was used, the development residue could not be removed regardless of the concentration.

[0287] [Table 9]

[0288]

[0289] A: The deposits from the development residue on the film surface are removed and the pores are visible.

[0290] B: The deposits are not removed and the pores cannot be seen

[0291] <Cleaning Experiment 2>

[0292] For a flexographic printing plate (AWP) which is developed by a developing device with an aqueous developer A added thereto TM-DEW (1.14mm, BL size)) was used to perform cross-flow filtration using a filter element (UMP-153) for a total of 20 times (a total of about 400L of filtration). In one filtration experiment, 80% of the volume of the aqueous developer waste liquid was obtained as a recovery liquid (16L of recovery liquid and 4L of concentrated waste liquid were obtained from 20L of the aqueous developer waste liquid). At this time, the supply pressure Pi of the aqueous developer waste liquid was 0.06Mpa, the outlet pressure Po was 0.04Mpa, the discharge pressure Pf was 0.01Mpa, and the circulation flow rate of the aqueous developer waste liquid was 2m / sec. Compared with the first time (new product state), the appearance of the membrane of the filter element was observed at the end of the twentieth filtration, and blackening was observed, so it was judged to be a clogged state, and immersion cleaning was carried out for 3 days with ULTRASIL 751% solution. The permeability of the surfactant in each state of the above-mentioned new product, clogged, and after cleaning was investigated (Table 10). The transmittance evaluation method is the same as that of the above-mentioned developer waste liquid recycling experiment.

[0293] [Table 10]

[0294] Developer A A A First filtration process temperature 20℃ 20℃ 20℃ Second filtration process temperature 20℃ 20℃ 20℃ Temperature Management have have have Filter component status New product block After cleaning Transmittance [%] 58 42 61

[0295] As can be seen from Table 10, high transmittance can be achieved by eliminating the clogging state, which is preferred.

[0296] Description of Reference Numerals

[0297] 1…Development system

[0298] 2…Developing device

[0299] 3…Processing device

[0300] 4…Flexographic printing plate

[0301] 5…Brush

[0302] 21…Developer tank

[0303] 31…Water-based developer waste liquid storage tank

[0304] 32…Circulation tank

[0305] 33…Filter components

[0306] 34…Filtrate tank

[0307] 35…Recovery liquid storage tank

[0308] 36…Concentrated waste liquid storage tank

[0309] 37, 38…Temperature regulator

[0310] 6, 211, 311, 321, 322, 331, 341, 351… delivery pipe

[0311] 210, 330, 340…return pipe

[0312] 8A, 8B, 8C…pressure gauge

[0313] 9A, 9B, 9C…Valve

Claims

1. A method for treating aqueous development waste liquid generated by developing a flexographic printing original plate using an aqueous developer, The processing method comprises: A first filtering step of filtering the aqueous developing waste liquid at a temperature of 5° C. to 48° C. using a precision filtration membrane to obtain a recovered liquid and a concentrated waste liquid; and A recycling step of recycling the recovered liquid for developing a flexographic printing original plate.

2. The treatment method according to claim 1, further comprising before the first filtering step: The temperature adjustment step is to adjust the temperature of the aqueous developing waste liquid to 5° C. or higher and 43° C. or lower.

3. The processing method according to claim 1 or 2, further comprising: In the second filtering step, the concentrated waste liquid is used as the aqueous developing waste liquid, and the first filtering step is repeatedly performed.

4. The processing method according to claim 3, wherein: During the second filtration step, the temperature of the concentrated waste liquid is controlled to be 5° C. or higher and 48° C. or lower.

5. The processing method according to claim 3, wherein: The aqueous developing waste liquid contains a surfactant, The permeability of the surfactant in the total of the recovered liquid obtained in the first filtration step and the second filtration step is 42% or more and 95% or less.

6. The processing method according to claim 5, wherein: The surfactant has a permeability of 55% or more and 95% or less.

7. The processing method according to claim 4, wherein: The aqueous developing waste liquid contains a surfactant, The permeability of the surfactant in the total of the recovered liquid obtained in the first filtration step and the second filtration step is 42% or more and 95% or less.

8. The processing method according to claim 7, wherein: The surfactant has a permeability of 55% or more and 95% or less.

9. The processing method according to claim 3, wherein: During the second filtering step, when the amount of the concentrated waste liquid is lower than a predetermined reference, new aqueous developing waste liquid is added to the concentrated waste liquid.

10. The processing method according to claim 3, wherein: When at least one of the following (A) to (F) satisfies the prescribed criteria, the concentrated waste liquid is discarded: (A) the total amount of the recovered liquid; (B) the number of times the new aqueous developing waste liquid is added to the concentrated waste liquid; (C) the total amount of the new aqueous developing waste liquid added to the concentrated waste liquid; (D) supply pressure of the aqueous developing waste liquid or the concentrated waste liquid to the filtration membrane; (E) an outlet pressure of the aqueous developing waste liquid or the concentrated waste liquid discharged from the filter membrane; (F) A circulation flow rate of the aqueous developing waste liquid or the concentrated waste liquid to the filtration membrane.

11. The processing method according to claim 6, wherein: When at least one of the following (A) to (F) satisfies the prescribed criteria, the concentrated waste liquid is discarded: (A) the total amount of the recovered liquid; (B) the number of times the new aqueous developing waste liquid is added to the concentrated waste liquid; (C) the total amount of the new aqueous developing waste liquid added to the concentrated waste liquid; (D) supply pressure of the aqueous developing waste liquid or the concentrated waste liquid to the filtration membrane; (E) an outlet pressure of the aqueous developing waste liquid or the concentrated waste liquid discharged from the filter membrane; (F) A circulation flow rate of the aqueous developing waste liquid or the concentrated waste liquid to the filtration membrane.

12. The processing method according to claim 8, wherein: When at least one of the following (A) to (F) satisfies the prescribed criteria, the concentrated waste liquid is discarded: (A) the total amount of the recovered liquid; (B) the number of times the new aqueous developing waste liquid is added to the concentrated waste liquid; (C) the total amount of the new aqueous developing waste liquid added to the concentrated waste liquid; (D) supply pressure of the aqueous developing waste liquid or the concentrated waste liquid to the filtration membrane; (E) an outlet pressure of the aqueous developing waste liquid or the concentrated waste liquid discharged from the filter membrane; (F) A circulation flow rate of the aqueous developing waste liquid or the concentrated waste liquid to the filtration membrane.

13. The processing method according to claim 3, further comprising: The cleaning step is to clean the filtration membrane with an acidic aqueous solution having a pH of 3 or less.

14. The processing method according to claim 4, further comprising: The cleaning step is to clean the filtration membrane with an acidic aqueous solution having a pH of 3 or less.

15. The processing method according to claim 6, further comprising: The cleaning step is to clean the filtration membrane with an acidic aqueous solution having a pH of 3 or less.

16. The processing method according to claim 8, further comprising: The cleaning step is to clean the filtration membrane with an acidic aqueous solution having a pH of 3 or less.

17. The processing method according to claim 13, wherein: The cleaning process comprises: immersing the filter membrane in the acidic aqueous solution; and / or The acidic aqueous solution is circulated in the filtration membrane.

18. The processing method according to claim 15, wherein: The cleaning process comprises: immersing the filter membrane in the acidic aqueous solution; and / or The acidic aqueous solution is circulated in the filtration membrane.

19. The processing method according to claim 16, wherein: The cleaning process comprises: immersing the filter membrane in the acidic aqueous solution; and / or The acidic aqueous solution is circulated in the filtration membrane.

20. A processing device for treating aqueous development waste liquid generated by developing a flexographic printing original plate using an aqueous developer, the processing device comprising: A water-based developing waste liquid storage tank, which stores the water-based developing waste liquid; A filter assembly having a precision filter membrane for filtering aqueous developer waste liquid; and A recovery liquid storage tank stores the recovery liquid generated by the filtration.

21. The processing device according to claim 20, further comprising a circulation tank for circulating concentrated waste liquid generated by the filtration in the filtration assembly.

22. The processing device according to claim 21, wherein The circulation tank has a temperature regulator.

23. A developing system comprising: The processing device according to any one of claims 20 to 22; as well as A developing device that discharges the aqueous development waste liquid by developing a flexographic printing original plate using an aqueous developer.

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