JP2008080229A - Method for treating waste developing solution of water-developable photosensitive resin developer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method for developer wastewater which is a disposal method of developer wastewater generated in the manufacturing processes of a printing plate using a water-developable photosensitive resin composition and is free from burning and sticking in a concentration kettle as well as easy in operation of wastewater treatment, and enables discarding or recycling of the developer wastewater at a low running cost. <P>SOLUTION: In a waste liquid treatment method where waste developing solution is vacuum evaporated at 2-5 kPa and at <30°C to be separated into an unexposed resin component and a condensate, the residual moisture content in the waste developer after the evaporation is concentrated to 10-20%, and then taken out to be discarded as fluid waste. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for disposing of a development waste liquid generated during the production of a printing plate using a photosensitive resin composition used for a relief plate for printing, more specifically, in a production process of a printing plate using a water-developable photosensitive resin composition. The present invention relates to a method for discarding generated developer wastewater.

  The water-developable photosensitive resin composition used for the relief plate for printing generally contains a water-soluble polymer, a photopolymerizable unsaturated group-containing monomer and a photopolymerization initiator as essential components, and if necessary, a stabilizer, Additives such as plasticizers are blended.

  The water-developable photosensitive resin composition is irradiated with actinic rays through a negative film (or positive film) having a transparent image portion to cure the exposed portion of the photosensitive layer, and then the non-exposed portion of the photosensitive layer with water. It is widely known to produce relief plates for printing by dissolving and removing.

When making a relief for printing using the above water-developable photosensitive resin composition, developer drainage is always generated, but the developer drainage cannot be discarded as it is, and it is disposed in accordance with legal regulations. There is a need. In response to recent environmental problems, there has been a demand for a waste liquid treatment method for reducing waste as much as possible in the process of creating a printing relief by a user.
Conventional techniques for solving the above problems include (1) a method of solidifying and discarding a developing waste solution with a flocculant (Patent Document 1), (2) filtering a hydrophobic and hydrophobic photosensitive resin in a developing wastewater, and the like. After separating and removing by a method, a method of recycling and recycling as a developer (Patent Document 2), (3) a method of burning wastewater in an incinerator, (4) a method of concentrating a developer after separating water by a concentration method Examples include a method of adding and solidifying and then taking out and discarding (Patent Document 3).
However, (1) is not preferable because a large amount of waste water is discharged, and (2) and (3) are complicated to separate and coagulate by adding a flocculant. Removal was not enough. On the other hand, (3) is not common because the method of burning in an incinerator requires a combustion facility, and (4) is expensive due to the addition of a flocculant, and it is burned in the condensing kettle. The problem is that the operability of taking out solid waste from the waste liquid treatment apparatus is poor.
JP 2001-47060 A JP 2003-057842 A WO2003-005129

  The present invention seeks to solve the above problems. The purpose is a method of disposing of development wastewater generated in the printing plate manufacturing process using the water-developable photosensitive resin composition used for the relief plate for printing. It is an object of the present invention to provide a processing method for developing waste water that is simple in operation and can be disposed of or reused at low running cost.

  As a result of intensive investigations to solve this problem, the inventors of the present invention have reduced the amount of waste resin by controlling the residual water content in the developer wastewater within a specific range using a concentration method, and processing. The present inventors have found that it is possible to satisfy the subsequent work of taking out waste, and have completed the invention.

That is, the present invention is as follows.
(1) After exposing the photosensitive resin plate capable of being developed in water, the developing waste solution generated when developing by removing the unexposed portion with a developer mainly composed of water is evaporated to obtain the resin component in the unexposed portion A waste liquid processing method for separating into a condensate, wherein the residual water content in the development waste liquid is concentrated between 10 and 20%, and then taken out and discarded as a fluid waste. (1) The photosensitive resin according to (1), characterized in that the waste liquid treatment method, (2) the development waste liquid separation method is a vacuum evaporation method with an atmospheric pressure of 2 to 5 kPa, and the temperature during concentration is less than 30 ° C. (3) A method for treating a photosensitive resin plate developing waste liquid according to (1) or (2), wherein the soluble polymer in the photosensitive resin composition used for the photosensitive resin plate is a hydrophilic polyamide, (4) Soluble in photosensitive resin composition used for photosensitive resin plate Polymer is a processing method of the photosensitive resin plate development waste of a partially saponified vinyl acetate (1) or (2).

    As is clear from the above description, according to the method for treating a water-developable photosensitive resin developing waste solution of the present invention, it is possible to reuse the treated development wastewater and reduce waste, and further, waste after concentration. Because of its excellent handleability, it contributes greatly to the industry.

    In the present invention, the water-developable photosensitive resin development waste liquid is a photosensitive resin using a water-developable photosensitive resin composition containing a soluble polymer compound, a photopolymerizable unsaturated group-containing monomer, and a photopolymerization initiator. It is a developer drainage obtained by developing the plate with water, and an optional development aid such as a surfactant or a lower aliphatic alcohol may be added. Specific examples of the water-developable photosensitive resin development waste liquid include soluble polymer compounds (for example, polyvinyl alcohol, polyamide, polyether ester amide, polyether amide, polyurethane, etc.), photopolymerizable or photocrosslinkable monomers (for example, Polyhydric alcohol acrylate, polyhydric alcohol epoxy acrylate, N-methylolacrylamide, etc.), photopolymerization initiator (eg, benzyl dimethyl ketal, benzoin dimethyl ether, etc.), heat stabilizer, plasticizer, surfactant, dye if necessary 1 is a developer drainage in which a photosensitive resin plate using a photosensitive resin composition containing an ultraviolet absorber or the like is dissolved in an unexposed portion for relief formation.

  The solid content concentration of the photosensitive resin composition in the developer wastewater is 10% by weight or less, particularly preferably 5% by weight or less, although there is no problem if the developer wastewater has fluidity. If the solid content concentration of the photosensitive resin composition exceeds 10% by weight, the fluidity of the developer drainage is poor, and piping clogging causes trouble in operation, which is not preferable.

In this invention, 10-20 weight% is preferable and, as for the water content rate in the concentration waste liquid after concentration, Most preferably, it is 10-15 weight%. If the water content in the concentrated waste liquid is less than 10% by weight, the fluidity required for removal is poor, and solidification after standing for 24 hours is incomplete, so the addition of a superabsorbent resin is necessary. On the other hand, when the water content in the concentrated waste liquid exceeds 20% by weight, the fluidity of the concentrated waste liquid is excellent, but since no solidification occurs after 24 hours of standing, it is necessary to add a superabsorbent resin. It is.
Therefore, this invention can satisfy the removal workability after concentration and solidification after standing for 24 hours by keeping the water content in the concentrated waste liquid after concentration between 10 to 20% by weight.

  In the present invention, as a method for removing water so that the residual water content in the developing waste liquid is in the range of 10 to 20% by weight, a heat concentration method may be mentioned. Examples of the heating concentration method include an atmospheric pressure heating concentration method and a reduced pressure heating concentration method, but a reduced pressure heating concentration method in which the boiling point in the concentration kettle can be lowered from the prevention of scorching of the photosensitive resin during concentration is preferable. The temperature in the concentration kettle is less than 30 ° C., preferably 20 ° C. or more and less than 30 ° C., because of the prevention of scorching on the wall surface of the photosensitive resin. If the temperature in the concentrating kettle exceeds 30 ° C, the photosensitive resin will be burnt on the wall of the condensing kettle, and less than 20 ° C is not preferred because the vacuum concentration efficiency is poor.

  In the present invention, as a method for efficiently concentrating the developer, it is preferable to perform the concentration with stirring. What is necessary is just to optimize the stirring method and stirring conditions according to a developing solution viscosity or a concentration apparatus.

    In the present invention, an antifoaming agent may be added to the developing solution when the developing solution aggregates. Examples of the antifoaming agent include higher alcohols, fats and oils, fatty acids, fatty acid esters, phosphate esters, mineral oils, silicones, and the like, but silicones are preferred in view of antifoaming properties. The antifoam additive is preferably added in an amount of 1 wt% or less to the developing waste solution from the economical aspect.

  Hereinafter, the present invention will be described in more detail with reference to examples. The part in an Example means a weight. The moisture content was measured by drying the obtained photosensitive resin developing waste liquid under reduced pressure, and comparing the weight after drying with the weight before drying to obtain the moisture content (% by weight).

Example 1
After 62 parts of ε-caprolactam, 38 parts of a nylon salt of N- (2-aminoethyl) piperazine and adipic acid and 100 parts of water were placed in a stainless steel autoclave, the air inside was replaced with nitrogen gas five times, and then 180 parts. Heated at 0 ° C. for 1 hour. Next, while the reaction temperature was raised to 240 ° C. over 45 minutes, the distilled water was gradually removed, and further heated for 2 hours while flowing nitrogen gas at a flow rate of 20 ml / min to obtain polyamide-1.

  55.0 parts of polyamide-1, 7.7 parts of N-ethyltoluenesulfonic acid amide, 0.02 part of 1,4-naphthoquinone, 0.03 part of 2,4-diaminoazobenzene, 50.0 parts of methanol and water 10 After mixing the polymer in a heated kettle with stirring for 2 hours at 60 ° C. to completely dissolve the polymer, 30.1 parts of acrylic acid adduct of diglycidyl ether of bisphenol A (chlorine content: 0.3 wt. %), 3.1 parts of methacrylic acid, 0.1 part of itaconic acid, 0.1 part of hydroquinone monomethyl ether, 13 parts of ammonium sulfite and 1.0 part of benzyl dimethyl ketal were dissolved for 30 minutes. Next, the temperature was gradually raised to distill methanol and water, and the mixture was concentrated until the temperature in the kettle reached 110 ° C. At this stage, a fluid and viscous photosensitive resin composition was obtained.

  Thickness having a coating of 15 μm in thickness comprising a reaction product of copolymerized polyester (Byron RV-300SS, manufactured by Toyobo Co., Ltd.), polyfunctional isocyanate (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) and brown dye. A 180 μm polyester film was used as a support, and the photosensitive resin composition was cast on the film-forming surface of the support to form a photosensitive layer. A polyester film having a thickness of 125 μm having a coating of 2 μm thick polyvinyl alcohol (AH-24, manufactured by Nippon Synthetic Chemical Co., Ltd.) is exposed to light using a laminator so that the coating side is in contact with the photosensitive layer. Laminated on the layer, a sheet-like laminate having a total thickness of 1080 μm was obtained. This laminate was solidified into a hard plate at room temperature. After 24 hours, this laminate was heated at 103 ° C. for 3 minutes to obtain a photosensitive resin original plate (raw plate).

  After this raw plate is stored for 7 days or more, the 125 μm polyester film is peeled off, and the test negative film (gray scale negative film for sensitivity measurement and image negative image for image reproducibility evaluation) is brought into vacuum contact with an ultrahigh pressure mercury lamp. For 40 seconds. Next, tap water is used as a developing solution, 20 liters of tap water is put in a brush-type washer (100 μmφ nylon brush, A3 size washer manufactured by GM Giken Co., Ltd.), and developed at 23 ° C. for 2 minutes to obtain an A3 size raw plate. Ten sheets were developed and a relief image could be obtained. The resulting developer had a solid content concentration of 5%. The result of evaluating the obtained relief plate was a photosensitive resin printing plate material having a fine line of 30 μm, an independent point of 200 μm, and a 150 line of 2%.

  20 liters of the obtained developer waste liquid is put into a 50 liter concentrating kettle that can be depressurized and heated to 100 ° C., and the residual water content is maintained at a vacuum degree of 4 kPa while maintaining the developer temperature in the inner kettle from 23 ° C. to 27 ° C. The vacuum distillation concentration treatment was performed for 8 hours until the rate reached 20%, and 1.2 kg of concentrated waste liquid was obtained. The concentrated waste liquid remaining in the kettle was fluid, and could be easily recovered by opening the valve at the bottom of the kettle. The recovered water recovered by distillation under reduced pressure had impurities of less than 1 wt% and could be reused as a developer. On the other hand, there was no scorching of the resin in the concentration kettle, and the handleability was excellent and it was not necessary to clean.

18.8 liters of the recovered water is returned to the developing machine, and a deficient amount of water is added to develop the A3 size plate, and the work of 20 liters of the obtained developing waste liquid is similarly concentrated by distillation under reduced pressure. I went twice. As a result of performing vacuum distillation concentration processing five times in total, the concentrated waste liquid remaining in the kettle is fluid and can be easily recovered by opening the valve at the bottom of the kettle, with excellent repeatability. there were. Further, the recovered water recovered by distillation under reduced pressure had impurities of less than 1 wt% and could be reused as a developer. On the other hand, the inside of the concentrating kettle was excellent in repetitive workability without the need for cleaning because the resin was not burnt in spite of repeated vacuum concentration 5 times.
Further, the obtained concentrated waste liquid was solidified by putting it in a transparent bag made of resin and allowed to stand for 24 hours, and it was not necessary to solidify by adding a superabsorbent resin. After solidification, it could be discarded as a plastic together with a resin bag.

Example 2
20 liters of developer waste solution obtained in the same manner as in Example 1 was put into a 50 liter concentrating kettle that can be depressurized and heated to 100 ° C., and while maintaining the developer temperature in the inner kettle from 23 ° C. to 27 ° C., vacuum The vacuum distillation concentration treatment was performed for 11 hours until the residual water content became 10% under the condition of 4 kPa, and 1.1 kg of concentrated waste liquid was obtained. The concentrated waste liquid remaining in the kettle was fluid, and could be easily recovered by opening the valve at the bottom of the kettle. The recovered water recovered by distillation under reduced pressure had impurities of less than 1 wt% and could be reused as a developer. On the other hand, there was no scorching of the resin in the concentration kettle, and the handleability was excellent and it was not necessary to clean.
Further, the obtained concentrated waste liquid was solidified by being left for 24 hours, and it was not necessary to solidify by adding a superabsorbent resin.

The recovered water (18.9 liters) is returned to the developing machine, and a deficient amount of water is added to develop the A3 size plate. I went twice. As a result of performing vacuum distillation concentration processing five times in total, the concentrated waste liquid remaining in the kettle is fluid and can be easily recovered by opening the valve at the bottom of the kettle, with excellent repeatability. there were. Further, the recovered water recovered by distillation under reduced pressure had impurities of less than 1 wt% and could be reused as a developer. On the other hand, there was no burning of the resin in the concentrating kettle despite repeated repeated vacuum concentration 5 times, and the repetitive workability was excellent without the need for cleaning.
Further, the obtained concentrated waste liquid was solidified by putting it in a transparent bag made of resin and allowed to stand for 24 hours, and it was not necessary to solidify by adding a superabsorbent resin. After solidification, it could be discarded as a plastic together with a resin bag.

Example 3
As polyvinyl alcohol, 100 parts by weight of partially saponified polyvinyl acetate having a polymerization degree of 650 and a saponification degree of 75% was dissolved at 80 ° C. in 200 parts by weight of a mixed solvent of ethanol / water = 30/70 (weight ratio). In this solution, 20 parts of the polyamide of Synthesis Example 1 was added and dissolved as the component (B). Thereafter, as component (C), 20 parts by weight of an unsaturated epoxy ester compound obtained by addition reaction of 1 mol of propylene glycol diglycidyl ether and 2 mol of acrylic acid, and addition reaction product 30 of 1 mol of glycidyl methacrylate and 1 mol of acrylic acid. Further, 3.0 parts by weight of dimethylbenzyl ketal as a photopolymerization initiator as component (D), 25 parts by weight of glycerin as a compatibilizer, and 0.05 hydroquinone monomethyl ether as a thermal polymerization inhibitor are added. Part by weight was added and stirred well.

  The photosensitive resin solution thus obtained was cast on a polyester film having a thickness of 200 μm previously coated with a polyester adhesive so that the film thickness after drying was 500 μm, and hot air at 60 ° C. The solvent was removed by placing in an oven for 5 hours.

On the photosensitive layer of the photosensitive resin sheet thus obtained, a water / ethanol = 50/50 solution is thinly applied, and an anti-adhesive layer of a polyvinyl alcohol polymer on a matted 100 μm polyester film. A cover film having a cover was attached by pressure bonding.

  After storing this photosensitive resin plate for printing in a dark place for 10 days, the cover film is peeled off, and the gray scale negative film for sensitivity measurement and the negative film for image reproducibility evaluation are brought into vacuum contact, and exposed to an ultrahigh pressure mercury lamp for 1 minute. did. Next, tap water is used as a developing solution, 20 liters of tap water is put in a brush-type washer (100 μm φ nylon brush, A3 size washer manufactured by GM Giken Co., Ltd.), developed at 23 ° C. for 2 minutes, and A3 size raw Ten plates were developed and a relief image could be obtained. The resulting developer had a solid content concentration of 5%. The result of evaluating the obtained relief plate was a photosensitive resin printing plate material having a fine line of 30 μm, an independent point of 200 μm and a 150 line of 3%.

20 liters of developer waste solution obtained in the same manner as in Example 1 was put into a 50 liter concentrating kettle that can be depressurized and heated to 100 ° C., and while maintaining the developer temperature in the inner kettle from 23 ° C. to 27 ° C., vacuum The vacuum distillation concentration treatment was performed for 11 hours until the residual water content became 10% under the condition of 4 kPa, and 1.1 kg of concentrated waste liquid was obtained. The concentrated waste liquid remaining in the kettle was fluid, and could be easily recovered by opening the valve at the bottom of the kettle. The recovered water recovered by distillation under reduced pressure had impurities of less than 1 wt% and could be reused as a developer. On the other hand, there was no scorching of the resin in the concentration kettle, and the handleability was excellent and it was not necessary to clean.
Further, the obtained concentrated waste liquid was solidified by being left for 24 hours, and it was not necessary to solidify by adding a superabsorbent resin.

The recovered water (18.9 liters) is returned to the developing machine, and a deficient amount of water is added to develop the A3 size plate. I went twice. As a result of performing vacuum distillation concentration processing five times in total, the concentrated waste liquid remaining in the kettle is fluid and can be easily recovered by opening the valve at the bottom of the kettle, with excellent repeatability. there were. Further, the recovered water recovered by distillation under reduced pressure had impurities of less than 1 wt% and could be reused as a developer. On the other hand, there was no burning of the resin in the concentrating kettle despite repeated repeated vacuum concentration 5 times, and the repetitive workability was excellent without the need for cleaning.
Further, the obtained concentrated waste liquid was solidified by putting it in a transparent bag made of resin and allowed to stand for 24 hours, and it was not necessary to solidify by adding a superabsorbent resin. After solidification, it could be discarded as a plastic together with a resin bag.

Comparative Example 1
20 liters of developer waste solution obtained in the same manner as in Example 1 was put into a 50 liter concentrating kettle that can be depressurized and heated to 100 ° C., and while maintaining the developer temperature in the inner kettle from 23 ° C. to 27 ° C., vacuum A vacuum distillation concentration treatment was performed for 11 hours until the residual water content became 5% under the condition of 4 kPa, and 1.05 kg of concentrated waste liquid was obtained. The concentrated waste liquid remaining in the kettle had no fluidity and could not be recovered even when the valve at the bottom of the kettle was opened. On the other hand, there was no scorching of the resin in the concentrating kettle, but the resin had to be removed because of the lump of resin adhering to the wall surface, and the handleability was poor.

Comparative Example 2
20 liters of developer waste liquid obtained in the same manner as in Example 1 was put into a 50 liter concentrating kettle that can be depressurized and heated to 100 ° C., and the developer temperature in the inner kettle was kept at 23 ° C. to 27 ° C. The vacuum distillation concentration treatment was performed for 11 hours until the residual water content became 30% under the condition of 4 kPa, and 1.3 kg of concentrated waste liquid was obtained. The concentrated waste liquid remaining in the kettle was fluid, and could be easily recovered by opening the valve at the bottom of the kettle. On the other hand, the resin in the concentration kettle was good without scorching of the resin, but the obtained concentrated development waste liquid was not allowed to solidify for 24 hours, but it was necessary to solidify by adding a superabsorbent resin. .

Comparative Example 3
20 liters of developer waste solution obtained in the same manner as in Example 1 was put into a 50 liter concentrating kettle that can be depressurized and heated to 100 ° C., and remained under the conditions of an inner kettle developer temperature of 125 ° C. and a vacuum degree of 4 kPa. The vacuum distillation concentration treatment was performed for 5 hours until the moisture content became 30%, and 1.3 kg of concentrated waste liquid was obtained. The concentrated waste liquid remaining in the kettle was fluid, and could be easily recovered by opening the valve at the bottom of the kettle. On the other hand, there was scorching of the resin in the concentration kettle, and it was necessary to remove the resin adhering to the wall surface, which was inferior in handleability.

  As described above, the development waste liquid treatment method of the present invention is excellent in removal workability and disposal workability, and further, the recovered water can be reused as a development liquid. Therefore, it can be advantageously used as a development waste liquid treatment method for photosensitive resin plates. it can.

Claims (4)

  After exposing the photosensitive resin plate that can be developed in water, the undeveloped portion is removed with a developer containing water as a main component, and the developing waste liquid generated during development is evaporated to obtain a resin component and a condensate in the unexposed portion. A method for treating a photosensitive resin plate developing waste liquid, characterized in that the residual water content in the developing waste liquid is concentrated to 10 to 20% and then taken out and discarded as waste.   The method for treating a photosensitive resin plate developing waste liquid according to claim 1, wherein the developing waste liquid is separated under reduced pressure by adjusting the pressure to 2 to 5 kPa, and the temperature during concentration is less than 30 ° C.   The method for treating a photosensitive resin plate developing waste liquid according to claim 1 or 2, wherein the soluble polymer in the photosensitive resin composition used for the photosensitive resin plate is a hydrophilic polyamide. The method for processing a photosensitive resin plate developing waste liquid according to claim 1 or 2, wherein the soluble polymer in the photosensitive resin composition used for the photosensitive resin plate is partially saponified vinyl acetate.