JPH05138131A - Degreasing washing method - Google Patents

Abstract

PURPOSE:To facilitate waste water treatment and to effectively wash mold release agents without leaving unwashed parts even if the mold release agents stuck on the wash differ in solubility by using pure water having the prescribed values of resistivity and temperature as washing liquid and constituting a washing process by an ultrasonic washing process and a spray washing process. CONSTITUTION:A washing process use pure water of >=10MOMEGA.cm resistivity and >=50 deg.C as washing liquid and is constituted by an ultrasonic washing process and a spray washing process. The washing liquid is fed to a spray nozzle 27 from multiple effect water purifying equipment 11 through a pure water feeding pipe 31 and sprayed from the nozzle 27. The washing water sprayed is collected in the bottom part of a spray chamber 26 and transferred to the bottom part of an ultrasonic washing tank 23 through a sprayed washing liquid recovery pipe 29. The washing liquid flows upward in the tank 23 from the bottom part and overflows the tank 23 to be collected in a trough 24 and is returned to the multiple effect water purifying equipment 11 through an overflow washing liquid recovery pipe 25 for reuse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, plastic molded products, and other materials such as glass for liquid crystals, plastic lenses, glass lenses, photomasks and disks.
The present invention relates to a degreasing and cleaning method for degreasing paraffin-based or soap-based release agents attached to articles such as ceramic substrates, crystals, heads, CCD glass, and precision machine parts.

[0002]

2. Description of the Related Art FIG. 4 shows an apparatus used in a conventional method. This device includes a mist room 41 and a shower room 42. The degreased cleaning object W is hung from the ceilings of the mist room 41 and the shower room 42. The cleaning object W to be degreased is an automobile bumper. The cleaning liquid L is stored in the mist room 41. Cleaning liquid L
Is an organic solvent such as trichloroethane. The cleaning liquid L is heated by the heater 43. The cleaning liquid that has been heated to become mist rises, is cooled by the cooler 44 and condenses,
It adheres to the article to be degreased W. Shower heads 45 are arranged at appropriate places in the shower room 42, and these heads are arranged.
From 45, a cleaning liquid consisting of the same organic solvent as described above is applied to the object W to be degreased. The article W to be degreased discharged from the shower room 42 is sent to the coating step of the next step.

As another method, there is known a method in which city water is added with an acid or an alkali as a cleaning liquid, and the cleaning liquid is sprayed on the object to be degreased.

[0004]

In the above method, the use of the organic solvent as the cleaning liquid is being restricted due to the problem of environmental pollution of the organic solvent, and the development of a method to replace it is awaited.

On the other hand, in the method of using city water to which acid or alkali is added as the cleaning liquid, a large amount of the cleaning liquid is used, so that a large amount of waste water is produced and the treatment thereof is a problem. An object of the present invention is to provide a degreasing cleaning method that solves the above problems.

[0006]

According to the degreasing cleaning method of the present invention, in the cleaning step, the resistivity is 10 MΩ · cm or more,
It is characterized in that pure water having a temperature of 50 ° C. or higher is used as a cleaning liquid, and the cleaning step includes an ultrasonic cleaning step and a spray cleaning step.

[0007]

In the degreasing cleaning method according to the present invention, since pure water is used as the cleaning liquid in the cleaning step, there is no problem of environmental pollution such as an organic solvent, and it is not necessary to use acid or alkali.

Pure water has a resistivity of 10 MΩ · cm or more,
Since the temperature is 50 ° C. or higher, impurities remaining on the object to be cleaned are suppressed to a minimum.

Further, since the cleaning process includes the ultrasonic cleaning process and the spray cleaning process, the release agent attached to the object to be cleaned has a different solubility like a paraffin type or soap type release agent. Even with a mold material, no cleaning residue occurs.

[0010]

Embodiments of the present invention will be described below with reference to FIG.

The device used in the method according to the invention is
As shown in FIG. 1, a multi-effect pure water producing apparatus 11, an ultrasonic cleaning apparatus 12, a spray cleaning apparatus 13 and a dryer 14 are provided. A city water (industrial water) supply pipe 21 and a drain pipe 22 are connected to the multi-effect pure water producing device 11. The multi-effect pure water producing apparatus 11 produces pure water having a resistivity of 10 MΩ · cm or more, a temperature of 50 ° C. or more, and a pressure of 8 kg / cm ² or more.
This pure water was obtained by passing city water through a reverse osmosis membrane and then passing a mixed type ion exchange resin through two stages, and its soluble solid content was 0.02 ppm.

The ultrasonic cleaning device 12 has an ultrasonic cleaning tank 23 equipped with an ultrasonic oscillator (not shown). An annular overflow cleaning liquid recovery gutter 24 is provided near the upper end of the outer surface of the ultrasonic cleaning tank 23 so as to surround the outer surface. One end of an overflow cleaning liquid recovery pipe 25 is connected to the overflow cleaning liquid recovery gutter 24, and the other end is connected to the pure water producing apparatus 11.

The spray cleaning device 13 is a spray chamber.
26 and a number of spray nozzles 27 arranged in place in the spray chamber 26. An inlet 26a and an outlet 26b are provided on both end walls of the spray chamber 26. A drainer 28 is provided at the outlet 26b.
At the bottom of the spray chamber 26 is a spray cleaning liquid recovery pipe 29.
Is connected to one end, and the other end penetrates into the ultrasonic cleaning tank 23 and reaches the vicinity thereof. In the spray nozzle 27,
One end of the pure water supply pipe 31 is connected, and the other end is connected to the multi-effect pure water producing device 11.

The dryer 14 has a suction chamber 32. An inlet 32a and an outlet 32b are provided on both end walls of the suction chamber 32. Further, a large number of suction ports 33 are provided at appropriate positions of the suction chamber 32, and a suction pipe 34 is connected to these.
Further, the suction chamber 34 has a clean air supply pipe 35.
Are connected.

Instead of the dryer 14, a hot air or cold air dryer, a far infrared ray dryer, a vacuum dryer or the like may be used.

Pure water supply pipe 31 from the multi-effect pure water production device 11
The cleaning liquid is supplied to the spray nozzle 27 through the spray nozzle 27, and the supplied cleaning liquid is sprayed from the nozzle 27. The sprayed cleaning liquid is collected at the bottom of the spray chamber 26 and sent to the bottom of the ultrasonic cleaning tank 23 by the spray cleaning liquid recovery pipe 29. The cleaning liquid sent to the ultrasonic cleaning tank 23 flows upward from the bottom of the tank and overflows. The overflowed cleaning liquid is collected in the gutter 24, is returned to the multi-effect pure water producing apparatus 11 in the overflow cleaning liquid recovery pipe 25, and is reused.

In the multi-effect pure water producing device 11, the collected pure water is concentrated and discharged through the drain pipe 22. The discharged pure water is subjected to wastewater treatment if necessary.
On the other hand, city water is replenished to the multi-effect pure water producing apparatus 11 by a city water supply pipe 22 as needed.

The item to be degreased is an automobile bumper.
The bumper W is an ultrasonic cleaning tank by suitable means not shown.
From 23, it is sent to the suction chamber 32 via the spray chamber 26 and discharged from the suction chamber 32.

First, an automobile bumper is an ultrasonic cleaning device.
As a preliminary cleaning at 12, the ultrasonic cleaning tank 23 is immersed and ultrasonic cleaning is performed. The ultrasonic wave used here is 40K
HZ is sufficient, but depending on the item to be cleaned, mega HZ
You may use the ultrasonic wave of the grade. Cleaning effect by ultrasonic waves,
Due to the cleaning effect of a high temperature (50 ° C or higher) cleaning liquid,
Effectively exerts detergency especially on soap-based release agents with high solubility. In addition, hydrogen peroxide (H
It is also possible to add an oxidizing agent such as 2 O2) that does not burden the wastewater treatment to enhance the cleaning effect.

Next, finish cleaning is performed by the spray cleaning device 13. The automobile bumper W is fed into the spray chamber 26 from the inlet 26a, and while being transported in the chamber 26, the cleaning liquid sprayed from the nozzle 22 is evenly dispersed, and the release agent adhering to the damper W is removed. It When the bumper W from which the release agent has been removed exits the spray chamber 26 from the outlet 26b, the cleaning liquid attached to the bumper W is drained by the drainer 28.

The pumper W exiting the spray chamber 26
Sent to the suction chamber 32, the suction chamber 32
While passing through the inside, the cleaning liquid adhering to the bumper W is completely dried.

Next, the cleaning effect of the method according to the present invention will be described.

Regarding the cleaning method, the method 1 is a case where only the spray cleaning is performed, and the method 2 is a case where the ultrasonic cleaning and the spray cleaning are combined.

The test was conducted on a bumper to which two types of mold release agents had adhered. Sample 1 having the paraffinic mold release agent adhered thereto and having soap type mold release agent adhered thereto Was designated as Sample 2.

The cleaning effect is judged by the paint adhesion. Paint adhesion is measured by the following test. After applying paint to the washed pumper, carve it into 100 grid-shaped 1 mm x 1 mm test pieces, attach tape to them, and peel off the tape. Count the number. The judgment was "good" if the test piece had zero peeling and "bad" if there was even one peeling. The judgment results are shown in Table 1.

[0026] As is clear from Table 1, when the mold release agent is of paraffin type, only spray cleaning is required, but when the mold release agent is of soap type, spray cleaning is combined with ultrasonic cleaning. It turns out that it is preferable to do.

The reason for this is that, as shown in FIGS. 2 and 3, the paraffin-based release agent and the soap-based release agent have different solubilities.

FIG. 2 shows a paraffin-based mold release agent as shown in FIG.
Shows the measurement results of the soap-based releasing agents measured by DSC (Finger Scanning Calorimetry). The heating program is as follows. The sample was heated to increase the temperature from 35 ° C to 150 ° C by 2 ° C per minute, held at 150 ° C for 10 minutes, and then decreased to 35 ° C by 2 ° C per minute. ..

In FIG. 2, the temperature is 1 after the heating start time A1.
At time A2, when the temperature increased by 0 ° C., the sample decomposed into two layers of solid and liquid. After that, the temperature of the sample is 100
At time A3 when the temperature rises to 0 ° C., the sample is decomposed into a liquid.

In FIG. 3, the sample remains a solid from the heating start time B1 to the time B2 when the temperature of the sample approaches 100 ° C., and then the sample is decomposed into two layers of solid and liquid and approaches 110 ° C. It changed to liquid at B3.

As is clear from the above, for the paraffin-based mold release agent, if the temperature of the cleaning liquid is about 50 ° C. or more, the cleaning power is effectively exhibited, but for the soap-based mold release agent, it is 50 It is presumed that the cleaning power will not be effectively exhibited with a cleaning liquid at about ° C.

[0032]

According to the present invention, there is no problem of environmental pollution such as an organic solvent, and it is not necessary to use an acid or an alkali, so that wastewater treatment can be easily performed.

Further, since the impurities remaining in the object to be cleaned are suppressed to a minimum, the treatment in the subsequent process can be carried out without any trouble.

Further, even if the mold release agent adhered to the object to be cleaned is a mold release material having a different solubility such as a paraffin type or soap type mold release agent, no cleaning residue occurs, so that cleaning is efficiently performed. It can be performed.

[Brief description of drawings]

1 is a layout of the apparatus used in the method according to the invention.

FIG. 2 is a graph showing the heat difference between fingers of a paraffin-based release agent.

FIG. 3 is a graph showing the heat difference between fingers of a soap-based release agent.

FIG. 4 is a layout diagram of an apparatus used in a conventional method.

[Explanation of symbols]

 11 Pure water production device 12 Ultrasonic cleaning device 13 Spray cleaning device 14 Dryer 23 Ultrasonic cleaning tank 26 Spray chamber 27 Spray nozzle 32 Suction chamber

Front page continuation (72) Inventor Hidetaka Sawada 5-3 28 Nishi Kujo, Konohana-ku, Osaka City Hitachi Shipbuilding Co., Ltd. (72) Takashi Hirano 5-3-28 Nishi Kujo, Konohana-ku, Osaka Hitachi Shipbuilding Co. In-house (72) Inventor Shoichi Momose 5-3-28 Nishikujo, Konohana-ku, Osaka City Hitachi Shipbuilding Co., Ltd.

Claims (1)

[Claims] 1. A resistivity of 10 MΩ · cm in the washing step.
As described above, the degreasing cleaning method is characterized in that pure water having a temperature of 50 ° C. or higher is used as a cleaning liquid, and the cleaning step includes an ultrasonic cleaning step and a spray cleaning step.