JPS60140239A - Method for stabilizing waste developer - Google Patents

Abstract

PURPOSE:To stabilize a waste developer by dissolving a specified percentage of Na2SO3 in the developer produced in a stage for washing out the unexposed part of a photosensitive resin composition so as to prevent the formation of a precipitate and the clogging of a nozzle even when the developer is stored for a long term. CONSTITUTION:Na2SO3 is dissolved in a waste developer produced in a stage for washing out a photosensitive resin composition contg. >=10wt% compound having polymerizable unsatd. double bonds such as unsatd. polyurethane or unsatd. polyester. The amount of the Na2SO3 added is 0.005-1.5wt%, and the compound may be used in the form of any of anhydrous and hydrated salts. The compound is added before the waste developer is stored. If may be added during the preparation of a fresh developer. When the waste developer is stored for a long term until exchange for a fresh developer or treatment in bulk is carried out, the formation of a precipitate and the clogging of a nozzle are prevented in an apparatus provided with a cast iron or galvanized iron vessel or pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for stabilizing waste liquid, and more specifically, the storage stability of the waste liquid is achieved by dissolving sodium sulfite in the developing waste liquid generated by washing out the non-exposed areas of a photosensitive resin. The present invention relates to a method for improving properties and preventing the occurrence of precipitation, etc.

Generally, development of the photosensitive resin composition after exposure is carried out using water, an aqueous surfactant solution, an aqueous alkaline solution, etc., depending on the composition of the photosensitive resin composition.

Such a developer is used until it has sufficiently dissolved the photosensitive resin and has no developing ability, and is then replaced with a new developer.The period until it is replaced with a new developer depends on the frequency of development. However, it usually lasts from one day to one week, but in some cases it can last for a month.Furthermore, if waste developer solution is treated in bulk and stored in a container such as a drum can, it may take an even longer period of time. There is.

In such cases, if the developing device or waste solution storage container is made of materials such as iron or zinc, the reactive elution components from the photosensitive resin contained in the developing solution may harden and separate, forming a precipitate, or causing damage to the device wall. It can stick to surfaces such as pipes and cause clogging of pipes, so periodic disassembly and cleaning is a must. Further, in an apparatus in which development is performed by spraying from a nozzle, there are problems such as the nozzle becoming clogged again and causing poor development.

In addition, when using a method of exposing from the support side in addition to image exposure, a large amount of biocured photosensitive resin components are dissolved in the developer, so separation is likely to occur, which is a particularly serious problem. Ta.

To prevent such problems from occurring, install f-? There is also a method of changing the material of the container to plastic such as PVC or stainless steel, but the former has problems with mechanical strength and it is difficult to replace the entire equipment material, and the latter has problems in terms of economy due to its high price. was there.

As a result of repeated studies to solve these problems that occur in developer waste, the present inventors have found that by dissolving and containing sodium sulfite in developer waste, precipitation does not occur even during long-term storage. This discovery led to the completion of the present invention.

That is, the present invention provides for developing waste liquid generated by washing out unexposed areas of a photosensitive resin that has been subjected to image forming exposure processing.
The object of the present invention is to provide a method for preventing the separation of dissolved photosensitive resin and the occurrence of precipitation by dissolving and containing sodium sulfite in a range of 0.005 to 1.5% by weight.

The sodium sulfite used in the method of the present invention may be anhydrous or a hydrated salt.

Sodium sulfite may be dissolved when preparing the developing solution, or it may be added and dissolved in the developing waste solution before storage, but it completely prevents precipitation in the developing device and nozzle clogging, etc. Therefore, it is preferable to add it when preparing a new solution. Further, the amount added is from o, o o s to 1.5% by weight. If the amount added is less than o, oosXIk%, sufficient effects cannot be obtained, and if it is more than 1.5%, the unmelted photosensitive resin composition will separate, which is not preferable. Further, from the viewpoint of eliminating the need for pH adjustment when treating waste liquid, the amount added is preferably 0.3% by weight or less.

According to the method of the present invention, even if the waste liquid comes into contact with metals such as iron and zinc, the generation of precipitates resulting from curing of the photosensitive resin composition can be prevented.

The developing waste solution to which the method of the present invention can be applied is a photosensitive resin composition containing 10% by weight or more of a compound having a polymerizable double bond, such as the one disclosed in Japanese Patent Publication No. 50-34964 1.
% Publication No. 52-7761, Special Publication No. 54-34930
Unsaturated polyurethane photosensitive resin composition as described in JP-A-56-120718, %
Publication No. H43-19t25, % Publication No. 50-3376
A photosensitive resin assembly product consisting of an unsaturated polyester photosensitive resin composition as described in Publication No. 7, water-soluble polyamide or partially saponified polyvinyl acetate, and a compound having a polymerizable double bond. It also contains the following. Among these, the larger the molecular weight of the compound containing double bonds, the more likely precipitation will occur, and therefore the method of the present invention is effective for photosensitive resin compositions containing such compounds.

Further, the developer may contain a known surfactant or alkaline compound suitable for the volatiles of the photosensitive resin composition to be eluted.

Hereinafter, the present invention will be explained with reference to Examples.

Example 1 1 mol of polypropylene glycol (molecular weight 2000), 1 mol of polypropylene glycol adibate diol (molecule i 2000), and 2.35 mol of toluylene diisocyanate were reacted to obtain a polyurethane having both ends inocyanate. This was reacted with polypropylene glycol monomethacrylate to obtain a polyurethane modified with methacrylate at both ends. 2 parts of polypropylene glycol monomethacrylate for 100 parts of polyurethane
5y-, lauryl methacrylate 15V-, tetraethylene glycol dimethacrylate) 107,2.2-dimethoxyphenylacetophenone 1.5? , 0.2 t of 2,6-di-t-butyl-p-cresol were mixed and dissolved to prepare a photosensitive resin composition.

This photosensitive resin composition was dissolved and dispersed in a 2% surfactant aqueous solution at a concentration of 3%. This liquid was divided into two beakers each containing 500 cc, and each piece of cast iron and galvanized iron pipe was immersed in the liquid. 0.2% by weight of sodium sulfite was added to one, and the other was stored without addition at 50° C. for 4 days, and the amount of precipitate and solidified deposits on the metal was examined. The results are shown in Table-1.

Table 1 Example 2 An A2 size negative film was placed on a horizontally placed glass plate, a 22 μm thick polypropylene film was placed on top of it, and the photosensitive resin composition used in Example 1 was placed on top of it. - Coated in thickness using a doctor knife. The surface of the photosensitive resin composition coated with T- was covered with a 100 μm thick polyester film. The polyester film was irradiated for 2 minutes from the side and for 5 minutes from the negative film side using a light beam lined with 10 20W ultraviolet fluorescent lamps. Next, the 22μ polyprohylene film was peeled off and developed by spraying a 2% surfactant aqueous solution (40°C) containing 0.2% sub-EW soda for 2 minutes at a pressure of 1,000 lbs. I did it. The material of the developer spraying device was cast iron and galvanized iron pipe.

After performing the plate development described above 20 times, the heating of the developer was stopped and the developer was left at room temperature for one week, but no precipitate was formed in the developing device, and the spraying operation of the developer σ was carried out for 30 minutes. However, the nozzle did not become clogged.

Comparative Example 1 The same experiment as in Example 2 was conducted except that a developer containing no sodium sulfite was used, and when the developer was sprayed after being left for one week, the nozzle immediately became clogged.

Example 3 0.3 mol of fumaric acid, 0.4 mol of adipine, 3 mol of isophthal rRo, 0.8 mol of diethylene glycol,
0.2 mol of propylene glycol was subjected to a dehydration condensation reaction to obtain an unsaturated polyester having an acid value of 27 [~KOVt].

This unsaturated polyester 100 f, tetraethylene glycol dimethacrylate) 30? , diethylene glycol dimethacrylate 10F, 2-hydroxyethyl methacrylate 20t, benzoin in butyl ether 5i, 2.6-di-t-butyl-p-cresol 0
．． 2t were mixed and dissolved to obtain a photosensitive resin composition.

This photosensitive resin composition was mixed and dispersed at a concentration of 2% in a developer containing 1% of sodium borate and 0.5% of a nonionic surfactant dissolved in water. This solution was examined in the same manner as in Example 1 for the amount of precipitate and assimilated deposits on metals. The results are shown in Table-2.

Table-2

Claims (1)

[Claims] A method for stabilizing a developer waste solution, which comprises dissolving 0.005 to 5% by weight of sodium sulfite in the developer waste solution generated by washing out the non-exposed areas of a photosensitive resin composition.