JP2003057852A - Method and system for treatment of stripped piece of resist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and system for treatment of stripped pieces of resist which reduces danger during recovery of the stripped pieces of the resist and makes a contribution to cost effectiveness and environmental protectiveness by reducing the moisture content of wastes to <=1/5 that hitherto known. SOLUTION: A remover is acted on the object for cleaning stuck with the stripped pieces of the resist to be stripped to separate the stripped pieces and an acid is acted on the separated stripped pieces of the resist to lower the pH of the stripped pieces and to make the characteristic of the stripped pieces plastic and thereafter, the stripped pieces are transferred to the ensuring stroke. In acting the acid to the stripped pieces, the pH may be once lowered down to about <=6 and then the pH may be regulated to about 7 by subjecting the stripped pieces to dilution by rising. The action of the acid and the rising to the stripped pieces may be carried out in the same fixed vessel and the operation to pour the cleaning water after discharging of the treated water may be repeated a plurality of times. The moisture content may be lowered down to <=100% by acting the acid to the stripped pieces to lower the pH thereof and to make the characteristic plastic then subjecting the stripped pieces to dewatering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of treating unnecessary substances generated in a printed board manufacturing process,
And an apparatus for implementing the method. In particular, the present invention relates to a method and an apparatus for collecting and processing an alkaline peeling piece generated when the resist is peeled off.

[0002]

2. Description of the Related Art Although a substrate manufacturing process using a photosensitive resin is the most popular technique at present, a large amount of unnecessary resist strips are generated in the resist stripping step after the photosensitization process. There is no effective means for separating and collecting the resist stripped pieces, and conventionally, separation by a method of separating on a mesh conveyor or a wire netting basket, or separation by a rotary backwashing method has been performed.

In these separation systems, the removal of the strong alkaline stripping solution having a pH of 11 or more, which remains on the resist strip, is performed.
It was difficult to do enough. Moreover, since the resist stripping pieces containing a large amount of stripping solution may be in the form of gel or sol and are not easy to handle, they were manually bagged without being neutralized and discarded as waste. . In the work, since a strong alkali deposit is handled, it is necessary to wear a protective suit such as a mask and a feather, and from the viewpoint of safety, the burden on the worker is very large. Further, since the waste becomes an environmental pollutant, the treatment cost is high, which is not preferable from the viewpoint of environmental protection.

Under these circumstances, the present inventor has studied a method of washing and neutralizing with a centrifugal dehydrator. However, since the stripping piece is Na-releasing, it takes a long time to process, and the mere washing neutralization causes a decrease in Na in the stripping piece and the washing water enters the stripping male piece. Difficult to fit. Therefore, in order to reduce the water content to 100% or less, a separate process such as drying is required.

[0005]

Therefore, the present invention reduces the risk at the time of collecting the resist strips and reduces the water content of the waste to ⅕ or less of the conventional one, thereby improving the economical efficiency. An object of the present invention is to provide a method for treating a resist strip, which also contributes to environmental protection, and an apparatus for carrying out the method.

[0006]

In order to solve the above problems, a method and apparatus for treating resist strips according to the present invention has the following constitution. That is, the stripping liquid acts on the purification target to which the resist stripping piece to be stripped adheres to separate the resist stripping strip, and the separated resist stripping strip is treated with an acid to adjust the pH of the resist stripping strip. Is lowered and the property of the resist strip is made plastic, and then the process is moved to the next step.

Here, when an acid acts on the resist strip, the pH of the strip is temporarily lowered to about 6 or less,
Then, dilute by washing with water to remove p from the resist strip.
H may be adjusted to about 7 to contribute to improving the action efficiency of the acid.

The action of the acid on the resist strip and the washing on the resist strip are performed in the same fixing tank,
The operation of injecting the cleaning water after discharging the treated water may be repeated a plurality of times to contribute to the simplification of the work and the apparatus.

Acid may be applied to the stripped resist to lower its pH, and its properties may be plasticized, followed by dehydration to reduce the water content to 100% or less, thereby contributing to the convenience of disposal.

In order to carry out such a method for treating resist stripping pieces, an apparatus for treating alkaline stripping pieces produced when stripping a resist, wherein the resist stripping pieces to be stripped are adhered On the other hand, a stripping means that acts a stripping solution to strip the resist stripping piece, and a fixing tank having a basket-like separating device for separating the resist stripping piece and the treated water are provided, and the action of the acid on the resist stripping piece An apparatus equipped with a neutralizing means for washing with water and a dehydrating means for reducing the water content of the resist strips is suitable.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the examples shown in the drawings. The embodiment of the present invention is not limited to this, and can be modified as appropriate. Figure 1
FIG. 3 shows an explanatory view of the apparatus for treating resist stripped pieces according to the present invention. In a printed circuit board manufacturing process using a dry resist film which is a photosensitive resin, a circuit pattern is printed on a substrate by exposure to light and developed, and then unnecessary resist is peeled off. This figure shows from the peeling step to the step of carrying out the resist peeled pieces after the treatment.

First, in the stripping machine (10), a strongly alkaline stripping solution is sprayed onto the developed printed circuit board, which is an object to be cleaned, from a spray pipe (10a) installed above the stripping machine (10). . Then, the unnecessary cured resist on the printed board is peeled off by the spray pressure. The necessary circuit pattern remains on the printed circuit board,
Since the peeling liquid is attached to the surface, the peeling liquid is transferred to the water washing machine by the conveyor for washing. In the washing machine, fresh water is sprayed from the spray nozzle to wash the printed circuit board. After that, the printed circuit board proceeds to a process such as drying.

In the stripping machine (10), the stripped resist strips fall in a state of being mixed with the stripping solution, and the mixed solution (L1) is temporarily stored in the lower part of the tank. Here, the mixed solution (L
In 1), the resist stripping piece which is a resin contains a large amount of water and softens, and is present in a gel or sol state which is very difficult to handle. Conventionally, this mixture is filtered,
The resist strips were collected and discarded with the high water content. However, this process is dangerous and at the same time deteriorates the production efficiency and causes a large amount of waste.
Therefore, in the present invention, a solid-liquid separation device (20) and
Various devices such as a neutralization device (30) and a dehydration device (60) are provided to automate the process.

Liquid mixture (L1) produced by the peeling machine (10)
Flows into the solid-liquid separation device (20) by the pump (12) via the service tank (11). The solid-liquid separation device (20) is a device for pressure filtration, and reduces the water content of the mixed liquid as the first step. In this step, the stripping solution is removed as a preparatory step for the next step, rather than strict solid-liquid separation. The stripping liquid (L2) separated here is sent to the stripping liquid supply tank (21). The stripper (L
2) is the peeling machine (10) again by the pump (24)
Returned to and used cyclically.

On the other hand, in the solid-liquid separation device (20), resist stripped pieces with a reduced water content remain. The solid-liquid separator (20) is automatically backwashed with water (L) at predetermined intervals.
3) is supplied from the backwash water supply port (s1). The remaining resist strips are discharged from the solid-liquid separation device (20) by the backwash water (L3) and face a resist strip transport conveyor (22) equipped with a rotary basket. The basket of the resist stripping piece conveying conveyor (22) is provided with a mechanism for dropping the resist stripping piece onto the conveyor, and the resist stripping piece conveyed by the conveyor is automatically put into the stripping piece supply tank (23).

A liquid level gauge and a controller (23a) for controlling the liquid level are installed in the stripping piece supply tank (23), and a purified water supply port (s2) is provided for pumping the received resist stripping piece. The dilution water is put in through the automatic valve (26). In this device, in order to stabilize the operation during acid supply and neutralization even when the equipment is made compact, the resist stripping piece is transferred while grasping the input amount by the liquid level controller (23a), and the input amount Injecting acid and dilution water that are suitable for. The peeling piece supply tank (23) is provided with a stirrer (23b) for diluting and stirring the resist peeling pieces to facilitate transfer.

The resist strips are stored in the strip strip supply tank (2
From (3), it is sent into the tank of the neutralizer (30) via the pump (25). Here, an acid such as sulfuric acid is supplied from the acid tank (40). For the resist strip, a strong alkaline solution (pH 11 to 11) containing ca. 4% of caustic soda as a stripping agent is used.
13) is included. In the resist strip,
Since Na is bound in the molecule, Na is difficult to elute by repeating normal washing with water and neutralization with water. About 1.2 mol of Na per 1 kg of dry weight is bonded to the peeled pieces of a typical resist film, and the cleaning efficiency is very low due to the sustained release property. In the case of washing with water, as the amount of Na decreases, the gel absorbs water and swells, so that the weight becomes larger than that before washing, and an auxiliary equipment such as a dehydrator is necessary for reducing the weight. However, dehydration of the gel-like resist strips is not easy, and there is a drawback that the equipment for drying equipment is large and energy cost is high.

Therefore, in the present invention, in order to solve such a problem, first, an acid acts on a resist stripping piece containing a strong alkaline solution to neutralize it. When an acid acts on the resist strip, the pH of the strip is once lowered to about 6 or less. If the pH is lowered to 4 or less, the neutralizing action will be saturated, so when considering the subsequent washing process, p
It is optimal to process H4 to H5. Since this acid treatment is a neutralization reaction, it terminates very quickly, and the water content after treatment depends on the pH at the time of neutralization, but it can be easily dried by performing centrifugal dehydration after neutralizing at pH 4 or less. A water content of about 60 to 100% by weight is obtained. Looking at the appearance of the stripped resist, it looks like a white slime when it contains a strong alkaline solution, and it remains in a slime just by washing with water, which makes it difficult to handle. However, with the decrease in pH due to the acid treatment, it rapidly changes to a blue base color.
Because of the discoloration and plasticization, the properties change from a slime shape to a resin fragment shape. This change is irreversible, and the property does not change even when contacted with water. This property is very convenient for treating with acid, washing with water to neutralize and discharging.

Inside the tank of the neutralization device (30), a basket (30
a) is provided. The basket (30a) is for efficient neutralization, and if necessary, cloth, paper,
A plastic net or the like is attached, and the resist stripping piece is designed to be left inside the basket (30a) and the cleaning water is discharged to the outside of the basket (30a). Neutralizer (30)
Is equipped with a stirrer (30b), and the resist stripping pieces are floated by neutralizing while stirring to enhance the neutralization efficiency and the water washing effect.

Acids such as sulfuric acid and hydrochloric acid are measured from the acid tank (40) via the pump (41) while neutralizing the neutralizer (3).
0). The pH adjustment (4
It is automatically performed by gradually narrowing the injection amount using 2). After the acid treatment for a certain period of time, waste water is dropped into the lower waste water tank (50) and new water is injected from the supply port (s2). Fresh water is injected by using the integrating flow meter (31) and the controller (32), and at the end of water injection, a PH controller is used to stably reduce the amount of water.
An automatic valve (33) for high-speed water injection is provided in the fresh water supply passage.
And a shutoff valve (34) for neutralization is provided.

The neutralization after the acid treatment employs a batch operation in which the neutralized water is discharged to the waste water tank (50) and the neutralization operation is repeated 2-3 times in order to save the amount of water. . 1
The pH is lowered by about 1 by one neutralization operation. Wastewater tank (5
0) is a resin or a corrosion resistant metal, and is a liquid level controller (50
By the control signal of a) or the customer's acid treatment equipment, the extraction valve (51) leading to the drainage port, the valve (52) leading to the wastewater treatment equipment, and the pump (53) are automatically operated.

The resist strips are fed into the tank of the dehydrator (60) via the suction pipe (61) and the pump (62). During the injection of the resist strip, auxiliary water is injected from the supply port (s3) through the automatic valve (63). The illustrated dehydrator (60) is a centrifugal dehydrator, and
Dehydration is effectively performed by a centrifugal action of about 00G. A spinning basket (60) for centrifugal rotation is provided in the tank of the dehydrator (60).
a) is installed. The rotation is performed by appropriately controlling the number of rotations at the time of injection or scraping. The rotation of the drive motor (60f) is controlled by an inverter or the like.

A cake (L4) of a resist stripping piece is attached to the periphery and bottom of the rotating basket. A pneumatic scraping device (60b) is provided to scrape the cake. The pneumatic scraping device (60b) has a supply port (s
4) Compressed air flows from the driver (60c) and the automatic valve (6).
0d). The tank of the dehydrator (60) is
It is a bottom extraction type and the cake outlet (60
e) is provided. A slide receiver (64) is installed below the cake discharge port (60e) so as to be openable and closable by an automatic valve (65) in order to prevent splash at the time of injecting the resist peeling pieces.

The resist stripping pieces (L
5) is dropped onto the conveyor (70) and the box (7)
1) It is packed in a PP bag set inside. When the collection bag is full, a new bag is automatically supplied by the conveyor.

In this embodiment, the centrifugal type dehydrator was mentioned, but the dehydrator is not limited to the centrifugal type, and a mesh conveyer and a vacuum suction are used as long as the residual moisture content is acceptable. A method, a method using a hot air dryer, a spray dryer, or a method using a cyclone method is also possible.

[0026]

The present invention has the following effects by having the above configuration. That is, since the neutralization treatment is performed with an acid,
The resist strips are made plastic, and the volume can be easily reduced to 1/5 or less by performing dehydration. Therefore, the environmental load is reduced by volume reduction,
Waste disposal costs can also be suppressed. Further, by making it plastic, the resist stripping piece changes from a difficult-to-handle slime shape to a plastic piece shape, and the subsequent handling becomes easy. The plasticized waste can be used as a reducing material for the blast furnace or can be used as another heavy-duty material. Since the processing of the resist strips is performed under automatic control, there is no danger as in the prior art, and the burden and labor of the operator is reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an outline of a processing device for a resist stripping piece.

[Explanation of symbols]

10 peeling machine 20 Solid-liquid separator 30 Neutralizer 30a basket 30b stirrer 31 Integrated flow meter 32 controller 33 Automatic valve for high-speed water injection 34 Neutralization shut-off valve 40 acid tank 41 pumps 42 pH adjuster 50 drainage tank 60 dehydrator s2 Fresh water supply port

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Haruhiro Yamashita             Asahi Kasei Co., Ltd. 1 No. 2 Samejima, Fuji City, Shizuoka Prefecture             In the company (72) Inventor Tadao Sano             Asahi Kasei Co., Ltd. 1 No. 2 Samejima, Fuji City, Shizuoka Prefecture             In the company F-term (reference) 2H096 AA25 AA26 LA25                 4F301 BF02 BF27 BF31 BG44 BG50                       CA09 CA61 CA63 CA64 CA68                 5F046 MA02 MA10

Claims (5)

[Claims] 1. A method for treating an alkaline stripping piece generated when stripping a resist, wherein a stripping solution is applied to a cleaning object to which the resist stripping piece to be stripped adheres to remove the resist stripping piece. Acid is applied to the separated resist strips to lower the pH of the resist strips, the properties of the resist strips are made plastic, and the process is moved to the next step. . 2. When an acid acts on the resist strip, the pH of the strip is once lowered to about 6 or less, and then diluted with water to adjust the pH of the strip to about 7. The method for treating a resist stripped piece according to claim 1. 3. The action of an acid on the resist strip and the washing of the resist strip in the same fixing tank, and after the treated water is discharged, the operation of injecting the wash water is repeated a plurality of times. The method for treating a resist stripped piece according to. 4. The resist stripping piece according to claim 1, wherein the resist stripping strip is acidified to lower the pH, plasticize its properties, and then dehydrated to reduce the water content to 100% or less. Processing method. 5. An apparatus for treating an alkaline stripping piece generated when stripping a resist, wherein a stripping solution is applied to an object to be purified to which the stripping target resist stripping is adhered to remove the resist stripping piece. A stripping means for stripping, a fixing tank having a basket-shaped separating device for separating the resist stripping piece and the treated water, a neutralizing means for effecting acid action on the resist stripping piece and washing with water, and a resist stripping piece An apparatus for treating stripped resist, comprising: dehydrating means for reducing the water content.