JPH11212275A - Method for regenerating developer for photosensitive resin letterpress - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily prepare a replenisher soln. and to enable reuse without reducing developing speed by developing a photosensitive resin letterpress contg. one or more of specified ionic hydrophilic groups with a developer prepd. by dissolving developing chemicals including an inorg. alkali metallic salt and a surfactant in water. SOLUTION: A photosensitive resin letterpress contg. one or more of ionic hydrophilic groups represented by -COOM, -SO3 M, -SO4 M and (-O)3n PO(OM)n [where (n) is 1 or 2 and M is H, a monovalent metallic atom or an ammonium compd.] is developed with a developer prepd. by dissolving developing chemicals including an inorg. alkali metallic salt and a surfactant in water. The development is carried out while replenishing the developer, part of which is discarded. The concn. of alkali metallic ions from an inorg. alkali metallic salt in a developer added is <=0.3 equiv./l, preferably <=0.25 equiv./l, further preferably <=0.2 equiv./l.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a photosensitive resin relief plate, particularly a developing solution generated when developing a photosensitive resin relief plate for flexographic printing. The developing solution containing the resin generated by the method of developing with a membrane is filtered through a membrane filter,
The present invention relates to a method for reusing a filtrate obtained when a dispersed resin is removed as a developer. More specifically, a carboxylic acid group, a carboxylate group, a phosphate group as a hydrophilic group,
Ultrafiltration of a developer containing, in a dispersed state, unexposed resin generated during the development process of a photosensitive resin relief plate containing phosphate groups, sulfonic acids, sulfonates, sulfate groups, and sulfate ester groups When the filtrate obtained by cross-flow filtration using one or more kinds of filtration membranes of a membrane and a microfiltration membrane is used again as a developer, the concentration of the inorganic alkali metal salt in the additional liquid is within a certain range. Accordingly, the present invention relates to a method for processing a photosensitive resin plate developer, which enables stable development of a large number of photosensitive resin plates for a long period of time without discarding the developer.

[0002]

2. Description of the Related Art A printing plate using a photosensitive resin is excellent in operability, productivity, price, and its printing characteristics as compared with a conventional printing plate, and has recently rapidly spread in various printing fields. As a method of developing a photosensitive resin plate, a method of forming a relief by blowing off an unexposed portion using compressed air, a method of forming a relief by spraying a developing solution at a constant pressure on a plate surface, a method of forming a plate in a developing solution And a method in which the unexposed portion is rubbed in a developer with a brush or the like has been devised and put to practical use. The developing solution for washing out the photosensitive resin plate by the developing method as described above is present in a state in which the unexposed portion of the resin washed out after development is dispersed, and when a large number of photosensitive resin plates are washed out, the developing solution contains The concentration of the resin increases, and as a result, the developing speed decreases, and the dispersed resin aggregates and forms a scum to adhere to the plate or brush. It was necessary to prepare a new developer.

[0003] In order to solve these problems, several methods have been devised for removing the resin component from the used developer and reusing it as a developer. As one of the methods, there is a method in which a resin is efficiently removed from a developer by performing cross-flow filtration using a membrane filtration membrane, and the filtered developer is used again for development. However, in this method, the resin is concentrated to a high concentration and is discarded together with the developing solution. Therefore, when the filtrate is used again as a developing solution, it is necessary to replenish the discarded developing solution. Is from about 10,000 to a maximum of about 0.2 micron when expressed in terms of molecular weight cut-off with a minimum pore size. Therefore, in the case of an aqueous solution in which a surfactant and an inorganic alkali metal salt are mixed as a developer, the inorganic alkali metal salt is used. Although the surfactant passes only 100% through the membrane filter, the surfactant passes only 50% or less, and the composition ratio changes between the initial developing solution and the developing solution of the filtrate. It was necessary to make a correction and change the addition ratio of the inorganic alkali metal salt and the surfactant from that at the time of preparing the first developer. In addition, since the preparation of the developing solution when adding the replenisher is complicated, the inorganic alkali metal salt and the surfactant are mixed at a fixed ratio in advance, and the mixture is added in an amount sufficient to supplement the insufficient surfactant when the replenisher is added. The development rate decreased during repeated reuse of the filtrate.
On the other hand, in a method of reusing a lithographic developer, a method has been devised in which a developing solution is prevented from being deteriorated by adding a replenisher so that an alkali component and another developer component are added to a filtrate so as to be larger than a developer. (Japanese Patent Laid-Open No. Hei 7-23451)
6). However, when this method was used as a method for processing a developer for a photosensitive resin relief printing plate, the development speed was gradually reduced.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to find a method of treating a developer which can be reused by simply preparing a replenisher and adding the replenisher without reducing the developing speed. It is assumed that.

[0005]

Means for Solving the Problems The present inventors have intensively studied and studied to solve the above-mentioned problems, and as a result, they have found that the cause of the decrease in developability is an increase in the concentration of alkali ions in the developer. Finally, the present invention has been completed.
That is, the present invention provides the following (a) as a hydrophilic group:
(B) Developing a photosensitive resin relief plate containing at least one of the ionic hydrophilic groups shown in (c) and (d) by dissolving a developing agent containing an inorganic alkali metal salt and a surfactant in water. Developed using the liquid, the used resin-containing developer is filtered through a membrane filter showing different transmittance characteristics between the inorganic alkali metal and the surfactant, and the filtrate is returned to the developing tank and used for development. Then, the resin-containing developer concentrated by filtration is discarded, and the developer lost by discarding is separately replenished. In the processing method of the developer, the alkali metal of the inorganic alkali metal salt in the additional developer is added. A method for regenerating a developer for a photosensitive resin relief printing plate, wherein the ion concentration is 0.3 equivalent / liter or less. (A) -COOM (b) -SO 3 M (c) -SO 4 M (d) (- 0) 3-n P0 (OM) n (n is 1 or 2) (M represents a hydrogen atom, 1 Represents either a valence metal atom or an ammonium compound)

The photosensitive resin composition used in the present invention is characterized in that it contains a hydrophilic component containing an ionic hydrophilic group in order to have developability in an aqueous developer. . The photosensitivity is imparted by adding a photopolymerizable unsaturated monomer, a photosensitizer and the like to any of these. As the hydrophilic component used in the present invention, various ones can be used.
Hydrophobic components to which a hydrophilic component is added, for example, those having a hydrophobic polymer modified with an ionic hydrophilic group as a main component, those having a hydrophobic polymer as a main component and ionic A mixture mainly composed of a hydrophilic component mainly composed of a hydrophilic polymer containing a hydrophilic group,
Mainly composed of chemically bonded hydrophobic polymer and hydrophilic polymer containing ionic hydrophilic group, hydrophilic polymer containing hydrophobic monomer and ionic hydrophilic group as raw material of hydrophobic polymer And those containing, as a main component, a polymer obtained by block-copolymerizing an ionic hydrophilic group-containing hydrophilic monomer as a raw material. In the present invention, a type in which a hydrophilic component is combined with a hydrophobic component in some form to form a photosensitive resin relief plate dispersed in an aqueous developer is particularly preferred.

In the present invention, the ionic hydrophilic group is
(A) to (d), that is, -COOM,-
SO ₃ M, -SO ₄ M, (-0) _3-n P0 (OM)
_n is a group represented by _n (n represents 1 or 2), and M represents any one of a hydrogen atom, a monovalent metal atom, and an ammonium compound. Examples of the monovalent metal atom include alkali metals such as sodium, potassium, and lithium.

Examples of the hydrophobic polymers mentioned here include 1,4-polybutadiene, 1,2-polybutadiene, acrylonitrile rubber, butadiene acrylonitrile rubber, chloroprene rubber, polyurethane rubber, butadiene styrene copolymer, styrene-butadiene-styrene block. Copolymer, styrene-isoprene-styrene block copolymer, polyamide resin, unsaturated polyester resin, butadiene- (meth) acrylic acid copolymer, butadiene- (meth) acrylic acid-acrylic ester copolymer, silicone rubber, polyoxypropylene glycol, polyoxytetra Polymers such as methylene glycol that give rubber elasticity to plates, polymethyl (meth) acrylate, polyethyl (meth) acrylate, polyisopropyl (Meth) acrylates, poly n-
Acrylic resin such as butyl (meth) acrylate, polystyrene, polypropylene, polyethylene, chlorinated polyethylene, polyacrylonitrile, polyvinyl chloride, polyvinyl acetate and copolymers thereof, polyurethane resin, polyester resin, polyamide resin, epoxy resin, etc. Such a plate may be provided with a polymer that imparts hardness and stability to the plate, and these may be used alone or in combination as necessary. These resins can also be modified so that they can react with a monomer or a crosslinking agent or between polymers.

Examples of the hydrophilic polymer include poly (meth) acrylic acid or a salt thereof, (meth) acrylic acid or a salt thereof-alkyl (meth) acrylate copolymer, (meth) acrylic acid or a salt thereof- Styrene copolymer, (meth) acrylic acid or salts thereof-vinyl acetate copolymer, (meth) acrylic acid or salts thereof-
Acrylonitrile copolymers, -COOM group or -SO ₃ M
Polyacrylates (the n 1 or 2) groups or -SO ₄ M groups and _{(-O) 3-n PO (} OM) n containing group, polyvinyl compounds, polyurethanes, polyurea urethanes, polyesters, epoxy compounds, polyamide and their And derivatives thereof. Similarly, a plurality of hydrophilic components can be used in combination, and may be modified as needed.

[0010] In addition to the raw materials for the photosensitive resin composition, a radical polymerizable monomer, a crosslinking agent, a photoreaction initiator,
An oxidation stabilizer, a polymerization inhibitor and the like may be added to the above-mentioned polymers as needed. Examples of the radical polymerizable monomer include styrene, vinyl toluene, chlorostyrene, t-butylstyrene, α-methylstyrene, acrylonitrile, acrylic acid, methacrylic acid,
Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, se
c-butyl (meth) acrylate, t-butyl (meth)
Acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, n-decyl (meth) acrylate, lauryl (meth) acrylate, n
-Tridecyl (meth) acrylate, stearyl (meth) acrylate, ethylene glycol mono (meth) acrylate, propylene glycol mono (meth) acrylate, diethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) ) Acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol monomethyl ether mono (meth) acrylate, polypropylene glycol monomethyl ether mono (meth) acrylate, polyethylene glycol monoethyl ether mono (meth) acrylate, polypropylene glycol monoethyl ether mono ( (Meth) acrylate, n-butoxyethyl (meth) acrylate, pheno Shiechiru (meth) acrylate, 2-phenoxypropyl (meth) acrylate,
Cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, glycidyl (meth) acrylate, allyl (meth) acrylate, benzyl (meth) acrylate, tribromophenyl (meth) acrylate, 2,3-dichloropropyl (meth) acrylate , 3-chloro-2-hydroxypropyl (meth)
Acrylate, N, N-diethylaminoethyl (meth)
Acrylate, N, N-dimethylaminoethyl (meth)
Acrylate, Nt-butylaminoethyl (meth) acrylate, acrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide and the like can be mentioned.

Examples of the crosslinking agent include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, Polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate,
Neopentyl glycol di (meth) acrylate, 1,
6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, glycerol allyloxydi (meth)
Acrylate, 1,1,1-trishydroxymethylethanedi (meth) acrylate, 1,1,1-trishydroxymethylethanetri (meth) acrylate, 1,
1,1-trishydroxymethylpropane di (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl terephthalate, diallyl 1 such as phthalate, divinylbenzene, polyurethane (meth) acrylate, polyester (meth) acrylate, etc.
Compounds having two or more radically polymerizable ethylene groups in the molecule include, but in addition, ethylene groups in one molecule,
Compounds having a plurality of reactive functional groups such as an epoxy group, an isocyanate group, an amino group, a hydroxyl group, and a carboxyl group are also included.

A preferred structure of such a photosensitive resin composition includes a structure in which a hydrophobic component (polymer) is a particulate dispersed phase and a hydrophilic component (polymer) is surrounded therearound to form a continuous phase. A core-shell particle in which the hydrophilic component (polymer) is a core and the hydrophilic component (polymer) is a shell, and a structure in which another hydrophobic component (polymer) is a continuous phase;
A structure in which the hydrophilic component (polymer) becomes a particulate dispersed phase and the hydrophobic component (polymer) becomes a continuous phase. Both the hydrophobic component (polymer) and the hydrophilic component (polymer) are entangled with each other in the continuous phase. A mosaic structure, a structure in which a hydrophobic component (polymer) and a hydrophilic component (polymer) are uniformly compatible, and the like can be given. In these cases, it is necessary that the continuous phase is not crosslinked in an uncured state, but the particulate hydrophobic component may be crosslinked in an uncured state or not.

The photosensitive resin composition is produced by mixing the components of the dispersed phase obtained by emulsion polymerization or suspension polymerization or by grinding the polymer alone or together with the components of the continuous phase in a kneader or an extruder. A method of molding, a method of kneading a hydrophobic component and a hydrophilic component in a lump state with a kneader or an extruder, and separating and dispersing the phases, followed by molding.A method of kneading or extruding a hydrophobic component and a hydrophilic component in a lump. Various methods are used, such as a method of kneading with a kneader and uniformly dissolving and then molding.

By appropriately selecting these raw materials and methods as needed, a photosensitive resin composition can be produced in accordance with the physical properties and performance required of the plate. For example, physical properties required for printing plates include JIS A
It is desirable in terms of printing characteristics that the hardness is 30 to 80 degrees and the rebound resilience is 20% or more. Such a photosensitive resin composition is cured by ultraviolet rays. The ultraviolet light used for curing has a wavelength of 150 to 500 nm, especially 300 to 4 nm.
A light source having a wavelength of 00 nm is effective, and the light source used is preferably a low-pressure mercury lamp, high-pressure mercury lamp, carbon arc lamp, ultraviolet fluorescent lamp, chemical lamp, xenon lamp, or zirconium lamp.

Next, in the present invention, the photosensitive resin plate is exposed to ultraviolet light by irradiating a negative film having a transparent image under the above-mentioned light source and exposing it to an image, and then removing the non-exposed non-image portion using a developing solution. By doing so, a relief image is obtained, while the uncured photosensitive resin dissolved and removed remains in the developing tank as an emulsion or suspension. Here, a developing solution containing water as a main component is used. The developer containing water as a main component is a solution obtained by adding a surfactant, an inorganic or organic alkali, an acid or a salt, and other compounds soluble in water to water. What added a metal salt and a surfactant is used.

As the surfactant, a wide variety of surfactants such as anionic surfactants, cationic surfactants, nonionic surfactants and amphoteric surfactants can be used. Aliphatic carboxylic acid salts such as sodium laurate, sodium stearate and sodium oleate, resin soaps such as sodium abietic acid and sodium rosinate, and primary and secondary alkyls such as sodium lauryl sulfate and triethanolamine lauryl sulfate Sulfates, primary and secondary polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate and triethanolamine sulfate, and alkylbenzenes such as sodium lauryl benzene sulfonate and sodium stearyl benzene sulfonate. Sulfone Salts, alkyl naphthalene sulfonates such as sodium propyl naphthalene sulfonate and butyl naphthalene sulfonate, polyoxyethylene alkyl phenyl ether sulfonates such as sodium polyoxyethylene lauryl phenyl ether sulfonate, sulfated castor oil and sulfated cattle oil Oils, sulfated fatty acid esters such as sulfated butyl oleate, alkyl sulfosuccinates such as sodium dioctyl sulfosuccinate, α-olefin sulfonates, hydroxyalkane sulfonates, N- Methyl-N-alkyl taurine salts, N-alkyl sulfosuccinic acid monoamide salts, fatty acid monoglyceride sulfate salts, alkyl diphenyl ether disulfonate salts, lauryl alcohol phosphate monoester disoda salt and lau Salts of alkyl phosphates such as sodium salt of dialkyl alcohol phosphate diester, salts of polyoxyethylene alkyl phosphate such as polyoxyethylene lauryl ether phosphate monoester disoda salt and polyoxyethylene lauryl ether phosphate diester soda salt, and naphthalene sulfonate formalin condensation And salts of partially saponified styrene-maleic anhydride copolymers and salts of partially saponified olefin-maleic anhydride copolymers. In addition, although a sodium salt was mainly mentioned as a specific example, a potassium salt, an ammonium salt, a magnesium salt, a calcium salt, etc. are also possible, and are not particularly limited to these.

Examples of the cationic surfactant include primary, secondary and tertiary amine salts such as monostearyl ammonium chloride, distearyl ammonium chloride and tristearyl ammonium chloride, stearyl trimethyl ammonium chloride, distearyl dimethyl ammonium chloride, stearyl. Quaternary ammonium salts such as dimethylbenzylammonium chloride, alkylpyridinium salts such as N-cetylpyridinium chloride and N-stearylpyridinium chloride, N, N-dialkylmorpholinium salts, fatty acid amide salts of polyethylenepolyamine, aminoethylethanolamine and stearin Acetates of urea compounds of amides with acids, 2-alkyl-1-alkyl-1-hydroxyethylimidazoli Umukuroraido, and the like. Although chloride is mainly mentioned as a specific example, bromide, alkyl sulfate, acetate and the like are also possible, and are not particularly limited to these.

Examples of the nonionic surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether and polyoxyethylene lauryl ether, and polyoxyethylene alkyl such as polyoxyethylene nonyl phenyl ether and polyoxyethylene octyl phenyl ether. Mono- and diesters of fatty acids such as phenyl ethers, polyoxyethylene polyoxypropylene glycols, polyethylene glycol monostearate, polyethylene glycol monooleate and polyethylene glycol dilaurate with polyethylene glycol, sorbitan monolaurate and sorbitan monooleate Esters of fatty acids and sorbitan, polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbita Esters of polyoxyethylene adducts of sorbitan such as monostearate and polyoxyethylene sorbitan trilaurate with fatty acids, esters of fatty acids with sorbite such as sorbit monopartitate and sorbit dilaurate, polyoxyethylene sorbit mono Esters of fatty acids such as stearates and polyoxyethylene sorbitdiolates with polyoxyethylene adducts of sorbitol and fatty acids, esters of fatty acids such as pentaerythritol monostearate with pentaerythritol, fatty acids such as glycerin monolaurate and glycerin Esters of fatty acids, fatty acid esters of sugar and sucrose, aliphatic alkanolamides such as lauric acid diethanolamide and lauric acid monoethanolamide, lauryl dimethylamine oxide Amine oxides such as id, aliphatic alkanol amines such as stearyl diethanolamine, polyoxyethylene alkylamine, triethanolamine fatty acid esters and the like.

Examples of the amphoteric surfactant include amino acid-type surfactants such as sodium laurylaminopropionate, carboxybetaine-type surfactants such as lauryl dimethyl betaine and lauryl dihydroxyethyl betaine, and stearyl dimethyl sulfoethylene ammonium ethylene. Examples include sulfobetaine-type amphoteric surfactants such as ammonium betaine, imidazolinium betaine-type amphoteric surfactants, and lecithin. Inorganic alkali metal salts include sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium tripolyphosphate, potassium tripolyphosphate, sodium pyrophosphate, potassium pyrophosphate, sodium silicate, potassium silicate, sodium borate, potassium borate, etc. And a salt compound exhibiting alkalinity.

Further, various additives such as salts, alkali compounds, viscosity modifiers, dispersion stabilizers, flocculants, zeolites and the like can be added to the developing solution of the present invention, if necessary. . Although it is an aqueous developer,
If necessary, other water-soluble organic solvents such as ethanol, isopropanol, cellosolve, glycerin, polyethylene glycol, dimethylformamide, dimethylacetamide, and acetone can be mixed. The pH of the developer is not particularly limited, but is preferably in the range of 3-12 from the viewpoint of safety in operation.
The temperature during development is preferably from 10 to 50 ° C.

According to the present invention, the developer containing the unexposed portion of the resin in a dispersed state, which is generated when the photosensitive resin plate is developed in this manner, is treated with an inorganic alkali metal and a surfactant having different transmittance characteristics. The developer in which the resin is dispersed is subjected to cross-flow filtration using a membrane filter showing the following to remove the resin in the developer, and the filtrate is reused as the developer. Examples of the material of the membrane filter include organic films such as polysulfone resin, polyimide resin, polyacrylonitrile resin, cellulose acetate, ethyl cellulose, and nitrocellulose, and ceramic films and alloys mainly containing alumina, silica, titanium oxide, zirconia, and the like. A sintered metal film,
And the like are not particularly limited.

As the form of the module, a hollow fiber or a tubular type is preferably used for an organic film, and a tubular type or a multi-lumen type is preferably used for a ceramic film or a metal film. As the filtration method in the present invention, a cross-flow method is preferably used in which the undiluted solution is circulated and passed through a filter membrane module, and a part of the solution is taken out as a filtrate. The flow rate of the stock solution through the filtration membrane module is desirably such that the flow rate of the raw water with respect to the filtration membrane is 0.2 m / sec or more.
If it is less than this, the filtration membrane is clogged or the filtration flow rate is significantly reduced. The pressure of the raw water applied to the filtration membrane varies depending on the type of the membrane, but is preferably 0.2 kg / cm ² or more. Further, in order to prevent a decrease in filtration flow rate due to blockage, the filtration membrane module may be provided with a mechanism for applying pressure from the filtrate side at regular intervals to perform backwashing.

In the present invention, the membrane filter having different transmittance characteristics between the inorganic alkali metal and the surfactant means that the transmittance y is represented by (concentration of solute in filtrate) / (concentration of solute in stock solution). In this case, the filter has different values of the transmittance ym of the inorganic alkali metal salt and the transmittance ys of the surfactant. In general, in a membrane filter, 100% of the inorganic alkali metal salt passes through other than the reverse osmosis membrane. However, since the surfactant takes a micelle structure in water, it does not pass 100% unless the pore size is 0.5 μm or more. Therefore, the minimum pore size range of the membrane filter used in the present invention is 1,000 or more in terms of the molecular weight cut-off, and the maximum is 0.2 μm or less in pore size. Also,
In order to secure a large filtration flow rate, the molecular weight cut-off
0000 or more, more preferably 50,000 or more,
Particularly, 100,000 or more is desirable.

From the filtrate thus obtained, the dispersed photosensitive resin has been removed, and the filtrate is returned to the developing tank as a developer and can be used again as a developer. on the other hand,
The concentrated solution containing a high-concentration resin generated by cross-flow filtration is discarded after removing the resin by a known method such as coagulation treatment, centrifugal separation, filtration treatment, drying under normal pressure or reduced pressure, or is subjected to water absorption. It can be discarded after solidification by the material, or incinerated and discarded as it is. In this case, in the present invention, since the liquid is concentrated to a high concentration and the amount of the liquid is small, the disposal thereof can be easily performed at a low cost.

Further, the filtrate is reused as a developer again, but since the developer is discarded together with the resin as a concentrated waste solution, the total amount of the developer is smaller than the initial amount after the processing.
Therefore, in order to regenerate the developer for a long period of time and perform stable development, it is necessary to add the developer. In the present invention, the concentration of the inorganic alkali metal salt in the developer to be added is important, and the concentration of the alkali metal ion in the developer is 0.3 equivalent /
It must be less than a liter. Preferably, 0.25
It is desirably equal to or less than equivalent / liter, particularly preferably equal to or less than 0.2 equivalent / liter. If it exceeds 0.3 equivalent / liter, the concentration of the inorganic alkali metal salt becomes too high, and the developing property is undesirably reduced. The concentration of the inorganic alkali metal salt of the developer to be added is 0.5 to 3 times, preferably 0.5 to 2.5 times, particularly 0.8 to 2.0 times the concentration of the inorganic alkali metal salt of the first developer. It is desirable that the concentration be twice as high as 0.5.
If the ratio is less than 2 times, the concentration of the inorganic alkali metal salt in the developer will be insufficient and the developability will be reduced. In the present invention, it is confused that the concentration of the inorganic alkali metal salt in the additional developer is the same as that of the initial developer, when the developer is first prepared and when the additional developer is prepared. Is most preferable because there is no possibility of occurrence.

In the present invention, the alkali metal ion concentration refers to the amount per unit volume of all the alkali metal ions contained in the developer, and includes those derived from inorganic alkali metal salts, those derived from surfactants, It is derived from other additives, and is the total of all existing as an ionic state in the developer. Further, the developer of the present invention also contains a surfactant, and may further contain other chemicals. Therefore, when a developer is added, these chemicals are also added at the same time. However, the compounding ratio of the inorganic alkali metal salt of the developing solution to be added and each of these chemicals is the same as the compounding ratio of the initial developing solution. It is particularly preferred because there is no risk of confusion at times. The additional developer of the present invention is an amount for supplementing the developer which is discarded together with the resin, and does not include water which is insufficient due to evaporation. The evaporated water can be replenished as appropriate. Also, the concentration of the developer to be added represents the ratio of the water to be added and the developing agent,
At the time of addition, the developing agent may be dissolved in water and added, or water and the developing agent may be separately added and dissolved.

[0027]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a perspective view of an embodiment of an apparatus used for a developing method and a developing solution regenerating method of the present invention. In FIG. 1, a resin-containing developer sent from a developing tank 14 is stored in a waste liquid storage tank 1. The waste liquid is sent from the waste liquid storage tank 1 to the filtration module 3 by the circulation pump 4 and subjected to cross-flow filtration.
The cross-flow liquid exiting the filtration module 3 is returned to the waste liquid storage tank 1 through the pipe 9 and repeatedly circulates in this line. On the other hand, the filtrate discharged from the filtration module 3 is sent to the filtrate storage tank 2. When filtration proceeds to a certain amount and concentration is completed, the filtrate is returned to the developing tank 14 by the pump 5, and
A predetermined amount of water, a surfactant, an additive and the like can be added and reused as a developer. On the other hand, the concentrated liquid in the waste liquid storage tank 1 is extracted by opening the concentrated liquid extracting valve 13, and is discarded. Here, the replenishment of the water, the surfactant and the additives was performed after returning to the developing tank, but it is needless to say that the replenishment may be performed in the filtrate storage tank. In FIG. 1, the filtrate discharged from the filtration module 3 is temporarily stored in the filtrate storage tank 2, but may be directly transferred from the filtration module 3 to the developing tank via a pipe.

The above description is of a batch-type treatment method. However, a part of the developing solution is always taken out or sent at predetermined time intervals, sent to a waste liquid storage tank, and the filtrate is constantly circulated and filtered while the developing solution is removed from the developing tank. The present invention is also possible with a continuous processing method returning to the above, and the present invention is not limited to these batch and continuous methods. Although these devices are equipped with the minimum equipment required for the present invention, a pre-filter, a pressure gauge, and a flow meter for preventing a large scum from flowing through the filtration module to block the flow passage in the module are provided. Equipment such as measuring instruments such as thermometers and thermometers, piping equipment such as bypass pipes, pumps and valves, temperature controllers such as heaters and cooling devices, and equipment that automatically supplies water, surfactants, and additives are provided as necessary. I can do it.

[0029]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In addition, each measured value in an Example is a value measured by the following method. (1) Membrane permeability: concentration of surfactant or inorganic alkali metal salt (surfactant Cs1, inorganic alkali metal salt Cm1) in the washing waste liquid in the concentration tank at the start of concentration,
The concentration of the surfactant or the inorganic alkali metal salt (surfactant Cs2, inorganic alkali metal salt Cm2) in the filtrate at the start of concentration was measured and calculated by the following equation. Membrane permeability (ys) of surfactant = Cs2 / Cs1 x
100 (%) Membrane transmittance (ym) of inorganic alkali metal salt = Cm2
/ Cm1 × 100 (%) (2) Concentration of surfactant and inorganic alkali metal salt: The developer was treated with an ultracentrifuge (10000 rpm, 30 rpm).
Minutes) to separate the solid content, take about 30 g of the clarified solution in an evaporating dish (weight (a) g) (total weight of the evaporating dish and the clarified solution (b) g), dry at 80 ° C. for 8 hours, and further add 120 1 in ° C
It was dried with a vacuum dryer at 30 mmHg for 5 hours (total weight of evaporating dish and nonvolatile components (c) g). Further, about 50 ml of ethanol was added to the evaporating dish, and the mixture was stirred at room temperature with a magnetic stirrer for 2 hours. Then, the ethanol solution was filtered through a Teflon membrane filter having a pore size of 5 microns together with the solid content remaining in the evaporating dish. The solid content on the evaporating dish and the filter was washed off, and then the solid content was dried together with the membrane filter at 60 ° C. for 5 hours. The solid content is weighed together with the membrane filter, and the weight (d) of the solid content is obtained by subtracting the weight of the previously weighed membrane filter. The concentration of the surfactant and the concentration of the inorganic alkali metal salt are as follows. I asked. Concentration of surfactant = (cad) / (ba) × 10
0 (%) Concentration of inorganic alkali metal salt = d / (ba) × 100
(%) (3) Concentration of inorganic alkali metal ion: 0.1 ml of the clarified solution of the developer subjected to ultracentrifugation in the same manner as above was weighed into a platinum crucible, and evaporated to dryness.
Ashing treatment for 0 hour, and adding 1.2m diluted hydrochloric acid 10m
1 was added. The diluted hydrochloric acid solution was measured with an atomic absorption spectrometer (AA-640-12, manufactured by Shimadzu Corporation) to quantify alkali metal ions.

Examples 1 to 7 A photosensitive flexographic printing plate (manufactured by Toyobo Co., Ltd., Cosmolite, CLH thickness 1.7 mm) was cut into A2 size, and a suitable negative having a thin line or a solid portion of each line width was cut. The film (50% exposed portion) was brought into close contact with the film, and irradiated with a mercury lamp having an illuminance of 25 W / m ² for 5 minutes to print a pattern. After removing the negative film, development was performed by rubbing with a nylon brush in various developing solutions at 40 ° C. so as to have a relief depth of about 1 mm. As described above, the developer after the development of a total of 10 photosensitive resin plates was processed according to the process shown in FIG. That is, the developer was transferred to the waste liquid storage tank 1, sent to the filtration module 3 by the circulation pump 4, and circulated between the filtration module 3 and the waste liquid storage tank 1 for cross-flow filtration. The filtrate was stored in the filtrate storage tank 2. When the amount of the concentrated liquid reached 5 liters, the filtration was stopped. The filtrate was returned to the developing tank by the pump 15, to which water and a developing agent were added and reused as a developing solution. This development and regeneration treatment was repeated three times a day for a total of 30 times. The developing agent used was a mixture of an inorganic alkali metal salt and a surfactant in advance. In addition, three types of hollow fiber type filter modules indicated by A, B, and C below were used. Table 1 shows the results. A: molecular weight cut-off 50,000 (HF5-43-PM50-PB manufactured by Coach Membrane System) B: molecular weight cut-off 500,000 (HF5-43-PM500-P)
B Same as above) C: 0.1 μm pore size (HF5-43-PMF0.1-PB
Ibid.)

[0031]

[Table 1]

COMPARATIVE EXAMPLES 1-6 Exposure and development were performed 10 times in the same manner as in Examples 1-7, and a regenerating process was performed. The concentration of the developing solution to be added was as follows: Was determined, and this amount was set as an amount that could be replenished. The developing agent used was the same as in Examples 1 to 7, in which an inorganic alkali metal salt and a surfactant were mixed in advance. Table 2 shows the results. C = C0 (X) r C: Surfactant concentration in waste concentrate C0: Surfactant concentration before concentration X: Concentration magnification (amount of developer before concentration / amount of concentrated developer) r: Surface activity The rejection of the agent (1-permeability of surfactant / 1)
00)

[0033]

[Table 2] As is clear from Table 2, when the concentration of the inorganic alkali metal ion in the additional developer exceeds 0.3 equivalent / liter, the developing speed is reduced to almost half.

[0034]

As described above, by adopting the method of the present invention having such a constitution, the developing operation of a large number of photosensitive resin plates can be stably performed for a long period without a decrease in the developing speed. Since the amount of the liquid waste liquid is small, the work such as the coagulation treatment is easy, the amount of the chemical used is small, and the cost is advantageous. Furthermore, since the total amount discharged as wastewater is small, it can greatly contribute to low pollution and local environmental conservation, and greatly contribute to the industry.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of an apparatus used for a method of regenerating a developer according to the present invention.

[Description of Signs] 1: Waste liquid storage tank 2: Filtrate storage tank 3: Filtration module 4: Circulation pump 5: Filtrate return pump 6: Piping from washing tank to waste liquid storage tank 7, 8, 9: Piping (waste liquid storage tank) 10: Piping from the filtration module to the filtrate storage tank 11, 12: Piping from the filtrate storage tank to the washing tank 13: Condensate extraction valve 14: Washing tank 15: Washing tank to waste liquid storage tank Pump 16 to liquid: Pressure gauge

Claims (1)

[Claims] (1) The following (a), (b), and
A photosensitive resin relief plate containing at least one of the ionic hydrophilic groups represented by (c) and (d) is prepared by using a developer obtained by dissolving a developing agent containing an inorganic alkali metal salt and a surfactant in water. After developing, the used resin-containing developer is filtered through a membrane filter showing different transmittance characteristics between the inorganic alkali metal and the surfactant, and the filtrate is returned to the developing tank and used for development again. The concentrated resin-containing developer is discarded, and the developer lost by the disposal is separately replenished. In a developer processing method in which development is performed, the alkali metal ion concentration of the inorganic alkali metal salt in the additional developer is reduced to 0. 3. A method for regenerating a developing solution for a photosensitive resin relief printing plate, wherein the amount is not more than 3 equivalents / liter. (A) -COOM (b) -SO 3 M (c) -SO 4 M (d) (- 0) 3-n P0 (OM) n (n is 1 or 2) (M represents a hydrogen atom, 1 Represents either a valence metal atom or an ammonium compound)