JP2005344210A - Mold cleaning solution, mold cleaning method and mold cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold cleaning solution and a mold cleaning method suitable for cleaning an ultrafine mold to which resin dregs having oil resistance, heat resistance and wear resistance are stuck. <P>SOLUTION: A main cleaning solution for use in the electrolytic cleaning as a main cleaning comprises a strongly alkaline component containing one or more selected from sodium hydroxide, potassium hydroxide and sodium carbonate, a chelating agent comprising EDTA4-sodium salt, and oxidized material removing component comprising an organic or inorganic nitrogen, and sodium gluconate. A purified water is used for the preparation of the main cleaning solution, which results in that the present method is suitable for the cleaning of a nickel mold used for molding a fine molded article. When a pre-cleaning is carried out before the electrolytic cleaning as a main cleaning, a pre-cleaning solution comprising a nonionic, cationic or anionic surfactant, sodium metasilicate and/or sodium orthosilicate and a chelating agent is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cleaning liquid, a cleaning method, and a cleaning apparatus for cleaning and removing deposits such as resin residue, rubber residue, glass residue, and gas burns attached to a molding die such as resin, rubber, and glass, and in particular, a fine structure metal The present invention is intended to improve a cleaning liquid suitable for use in the main cleaning in which the mold cleaning is performed by electrolytic cleaning, and a pre-cleaning performed before the main cleaning and an auxiliary cleaning liquid used for post-cleaning as necessary.

In recent years, with the reform of molding materials for resin and rubber and the advancement of molding technology, parts made of metal or glass, which have been formed by conventional press processing, etc., have also been molded with molds that can be mass-produced. It is shifting to resin parts.
For example, resin products and rubber products have been considered to have poor strength, heat resistance, oil resistance, and wear resistance compared to metal products and glass products. Distributor cases that are installed in the hoods of automobiles that require heat resistance and oil resistance are also changing from metal products to resin products.
In addition, with advances in ultra-precision molding technology, TV screens and lenses are changing from glass to resin. Ultra-precision parts such as light guide plates for flat panel displays, lenses for ultra-small precision cameras for mobile phones, goggles lenses, gears, connectors, etc. are mass-produced by resin molding.

  A mold used for molding the resin, rubber, glass or the like has a resin residue, a rubber residue, or a glass residue attached to its inner surface according to the amount of molding, and a gas generated when the resin is dissolved. These deposits accumulate on the mold surface as the number of shots increases as the molding shots are repeated, and cannot be easily removed. However, if these are not reliably removed, inconveniences such as lead to molding defects occur. Therefore, the molding die must be periodically removed and washed to remove the deposits.

  In particular, molds for injection molding flat panel display light guide plates, mobile phone ultra-small precision camera lenses, goggles lenses, vehicle reflectors, etc. have a pure nickel plating layer, phosphorus or boron on the surface of iron or brass. A mold provided with a blended nickel alloy plating layer, a mold having a nickel plate or a nickel alloy plate attached to the surface, and a mold formed only of nickel or a nickel alloy (hereinafter referred to as nickel mold) And collectively referred to as a mold). In this type of nickel mold, since nickel has a characteristic of easily adsorbing a substance, metal fine particles, fine resin pieces, and foreign matters that are deposited in the electrolytic solution are likely to adhere. If these ultrafine particles remain attached to the nickel plating surface, there is a problem that the quality of the light guide plate, lens, and reflector formed by the nickel mold cannot be maintained. In particular, the light guide plate cannot cope with higher precision unless the resin that has entered the fine and precise pattern is removed or dirt such as edges of parts that easily collect gas is removed.

  Mold cleaning has been done by dipping in trichlene or hydrocarbon-based petroleum and then rubbing with a brush or cotton swab, but trichlene or hydrocarbon-based organic solvents adversely affect the human body. .

In view of the above problems, the present applicant uses a cleaning liquid in which a strong alkali component such as sodium hydroxide is blended, and as a cleaning device for a molding die in Japanese Patent Application Laid-Open No. 7-214570 (Patent Document 1). The electrolytic cleaning apparatus shown in FIG. 8 is provided.
This cleaning apparatus has an advantage that the mold can be cleaned efficiently in a short time by using both electrolytic cleaning and ultrasonic cleaning. In FIG. 8, 1 is a cleaning tank, 2 is a mold holding basket that is detachably inserted into the cleaning tank, and 3 is a positive electrode suspended in the cleaning tank, and the mold holding basket on the negative electrode side. 2 and an ultrasonic vibration is generated in the electrolytic cleaning liquid in the cleaning tank by the ultrasonic vibrator 4 attached to the bottom surface of the cleaning tank 1. And the ultrasonic cleaning are used together to clean the mold 5.

  Further, in Japanese Patent Laid-Open No. 2001-241000 (Patent Document 2), a degreasing tank 6 that performs pre-cleaning of the main cleaning tank 1 ′ that performs electrolytic cleaning shown in FIG. 9 and post-cleaning after the main cleaning by the main cleaning tank 1 ′. A mold cleaning apparatus provided with a rinsing tank 7 is provided. The mold cleaning apparatus is configured such that a degreasing tank that performs pre-cleaning and a rinse tank that performs post-cleaning are attached to the main cleaning apparatus that performs the same electrolytic cleaning as the mold cleaning apparatus of Patent Document 1. .

In Patent Document 1, an alkaline solution containing sodium hydroxide and / or potassium hydroxide, an alkali salt of EDTA, and sodium gluconate is provided as a cleaning liquid used in the main cleaning for electrolytic cleaning. Moreover, the temperature control apparatus is attached and the temperature of the washing | cleaning liquid is heated to 30-70 degreeC.
Also in Patent Document 2, as the electrolytic solution used in the main cleaning in which electrolytic cleaning is performed, the same cleaning solution made of sodium hydroxide, EDTA, a surfactant, and water is used.
In the pre-cleaning degreasing tank, an organic degreasing solvent such as ether or alcohol is used as the pre-cleaning liquid, and the pre-cleaning is performed in an open configuration in which the mold is mounted and immersed in the degreasing tank and is not sealed with a lid or the like. It has been broken.

JP 7-214570 A JP 2001-241000 A

  Since the mold cleaning apparatus of Patent Document 1 uses both electrolytic cleaning and ultrasonic cleaning, the deposit on the mold can be removed very efficiently in a short time, and the cleaning effect is excellent. However, recently, as described above, the number of ultra-precision molded parts such as light guide plates of flat panel displays has increased rapidly. In these ultra-small precision component molds, the unevenness becomes fine, and it is difficult to remove the fine recesses, particularly the resin debris attached to the corners of the recesses, and the ultrafine resin debris tends to remain. In recent years, resins having improved physical properties such as heat resistance, oil resistance, and abrasion resistance are increasing, and even in the case of molds for resin molding, it is difficult to remove the resin residue.

In order to solve the problem, it is necessary to increase the cleaning power.
However, in particular, in the resin mold having improved heat resistance, oil resistance, and wear resistance, the resin residue does not easily melt and swell even when the temperature of the cleaning liquid is increased, so that these Removal of the resin residue is difficult.
In addition, when a cleaning liquid with an increased amount of a strong alkaline substance such as sodium hydroxide is used, troubles that corrode the mold occur.
Furthermore, it is considered that the cleaning ability is physically enhanced by combining ultrasonic vibration and stirring the cleaning liquid. The lower the frequency of ultrasonic waves is, for example, from 50 KHz to 20 KHz, the stronger the force to remove dirt, but the destructive force due to ultrasonic vibration also increases proportionally, and damage to the mold will occur if the cleaning time is prolonged. . In particular, a nickel mold for forming the light guide plate of the flat panel display has a problem that the nickel layer on the surface is easily damaged by ultrasonic waves.

Further, as a method for enhancing the cleaning capability, it is described in Patent Document 2, and the pre-cleaning and post-cleaning methods performed by those skilled in the art from before the application of Patent Document 2 have been improved, so that pre-cleaning and main-cleaning are performed. Also, it is possible to adopt a method of improving the cleaning ability in the total after-cleaning.
However, even if a pre-cleaning liquid composed of an organic degreasing solvent such as ether or alcohol is used in the degreasing tank described in Patent Document 2, the enhancement of the detergency is not observed according to the applicant's additional test. It was.
In addition, washing with water in a rinsing tank after the main washing of electrolytic washing has been conventionally performed, but there is a problem that rust is likely to be generated in the mold only by washing with water.

  The present invention has been made in view of the above problems, and by improving the cleaning ability by modifying the pre-cleaning liquid used for the pre-cleaning and the main cleaning liquid used in the main cleaning for electrolytic cleaning, heat resistance, It is an object to increase the cleaning ability so that the resin residue having oil resistance and wear resistance can be reliably removed even when it adheres.

  In order to solve the above-described problems, the present invention firstly provides non-ion, cation, or anion-based pre-cleaning liquid used in pre-cleaning before main cleaning for electrolytic cleaning and post-cleaning liquid used in post-cleaning as necessary. A mold cleaning liquid characterized in that it contains a surfactant, sodium metasilicate or / and sodium orthosilicate, and a chelating agent.

As the auxiliary cleaning liquid comprising the pre-cleaning liquid and the post-cleaning liquid, the present inventor prepared cleaning liquids containing various components, and repeated experiments using the same. As a result, the pre-cleaning liquids also include surfactants, chelating agents and oxides. It is obtained by knowing that the pre-cleaning ability can be enhanced by blending the removal component and, in particular, blending metasilicate or / or orthosilicate.
Examples of the chelating agent include EDTA tetrasodium salt and carboxylic acid-containing sodium salt. Examples of the oxide removing component include organic nitrogen, or inorganic nitrogen containing nitrate or ammonium salt.

In particular, when the pre-cleaning liquid is used in a state of being heated to about 40 ° C. to 100 ° C., the cleaning ability can be enhanced.
Furthermore, at the time of the pre-cleaning, the upper opening of the pre-cleaning tank is sealed with a lid and heated. In other words, if heated in a pressure kettle, the boiling point increases and the temperature can be raised, so that the cleaning ability can be increased. In addition, since it is sealed with a lid, the safety of workers can be enhanced.
In addition, even if it wash | cleans with the pre-cleaning liquid which consists of the said component even if it seals with a lid | cover and does not boil a pre-cleaning liquid, a cleaning capability can be improved conventionally, In that case, 40 to 60 degreeC from the safety | security of an operator. It is preferable to heat to the extent.

When the pre-cleaning is performed using the auxiliary cleaning liquid before the main cleaning, the following effects can be obtained.
Heat conduction grease (for example, heat conduction grease KS-609 made by Shin-Etsu Chemical Co., Ltd.) and heat conduction paste (Japan Mold Industry Co., Ltd. Sales Infrastructure Coat IKB) to improve the heat conduction of the heater attached to the mold Is used, metal powder that causes trouble during cleaning, particularly electrolytic cleaning, is contained in the heat conductive agent. Specifically, the thermally conductive grease contains 75% zinc oxide, and the thermally conductive paste contains 30% copper, 25% graphite, and 10% aluminum.
When the metal powder contained in the heat conductive grease and heat conductive paste flows out into the cleaning liquid and adheres to the mold surface by substitution reaction or electrolytic deposition, it can be easily removed with sodium hydroxide. Cause trouble.
In addition, the thermal conductive agent contains copper and zinc oxide that easily precipitate on the surface of the iron mold due to substitution reaction, and further contains aluminum that corrodes iron when electrolyzed. Furthermore, since porous graphite that adsorbs organic matter is contained, the surfactant contained in the cleaning liquid is also adsorbed, and it has the effect of preventing the reattachment of dirt to the mold and the prevention of mist scattering that occurs during electrolysis. Disappear.
In order to prevent the trouble, EDTA4 is mainly composed of a nonionic surfactant that saponifies the thermally conductive grease or paste, sodium metasilicate, or sodium orthosilicate before electrolytic cleaning mainly containing sodium hydroxide. Pre-cleaning is performed in advance using an auxiliary cleaning liquid composed of a chelating agent such as sodium, and after removing the thermal conductive agent, an electrolytic cleaning liquid composed of a strong alkali such as sodium hydroxide is used to achieve heat resistance, oil resistance, This has the effect of shortening the main cleaning time for removing the resin having excellent wear characteristics.

The present invention secondly, as the main cleaning liquid used at the time of electrolytic cleaning,
This cleaning solution for electrolytic cleaning is a strong alkaline component containing at least one selected from sodium hydroxide, potassium hydroxide and sodium carbonate, a chelating agent consisting of EDTA tetrasodium salt, and an oxidation consisting of organic nitrogen or inorganic nitrogen There is provided a mold cleaning liquid characterized by containing a product removing component and sodium gluconate.

Using nitrate or ammonia salt as the inorganic nitrogen,
As the organic nitrogen, ethylenediamine selected from ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenebexamine,
As the chelating agent, hydroxyethyliminodiacetic acid sodium salt, nitrilotrisetecate-3sodium (NTA.3Na), dicarboxymethyl-glutamic acid tetrasodium-4sodium (GLDA.4Na) is preferably used.

  As described above, this cleaning liquid is composed of a strong alkali component containing one or more selected from sodium hydroxide, potassium hydroxide, and sodium carbonate, sodium gluconate, a chelating agent composed of tetrasodium EDTA, and organic nitrogen or inorganic. By compounding an oxide removing component to which nitrogen is added, the oxide removing performance is further enhanced as compared with the case of using the chelating agent alone.

  Further, when one or more surfactants selected from nonionic, cationic, and anionic surfactants are included, the detergency can be further enhanced and the resin residue and other molds removed from the mold can be obtained. It has a function to suppress the re-adhesion of mist and generation of mist.

Specifically, the cleaning liquid is a strong alkali component of 30 to 100 g / liter, the EDTA tetrasodium salt of 30 to 100 g / liter, sodium gluconate of 10 to 60 g / liter, removal of oxides composed of organic nitrogen or inorganic nitrogen. It is preferable to blend the components in an amount of 30 to 150 g / liter.
Moreover, when mix | blending 1 or more surfactant selected from the said nonionic, cationic, and anionic surfactant, it is preferable to mix | blend 1-3 cc / liter.
The compounding amount was discovered by the present inventors through repeated experiments.

In addition, it is preferable that the cleaning liquid is provided with a heating means and heated to 30 ° C. to 60 ° C. from the viewpoint of improving the cleaning ability.
When performing this electrolytic cleaning using this main cleaning liquid, and more preferably using ultrasonic cleaning together, it is possible to perform cleaning by covering the upper surface opening of the cleaning tank with a hood to control the temperature of the cleaning liquid and mist scattering. And is preferable from the viewpoint of preventing the diffusion of odors.

The main cleaning liquid, the pre-cleaning liquid and / or the cleaning liquid used in the post-cleaning performed after the main cleaning is mixed with water, and the water is mixed with water from which impurities have been removed through purification means. It is preferable.
As the purification means, a purification means employing distillation, ion exchange or / and filtration can be used.
This is because tap water contains foreign substances such as silica and calcium, and when the mold to be cleaned is a high-density mold such as the nickel mold, the foreign substances such as silica and calcium contained in the cleaning liquid are molds. This is because it may be attached to the surface and reduce the precision of the mold and cause molding defects. Therefore, it is preferable to remove foreign matters such as silica and calcium from the tap water by the purification means.

As a second invention, a mold cleaning method is provided, and the mold cleaning method includes:
Mold cleaning, wherein the main cleaning liquid is used during the main cleaning of the electrolytic cleaning, the pre-cleaning liquid is used when performing pre-cleaning, and the post-cleaning is performed when performing the post-cleaning liquid as necessary. Providing a way.
Depending on the mold to be cleaned, it is preferable to perform only main cleaning and only pre-cleaning → main cleaning → post-cleaning, or it is preferable to perform main cleaning and post-cleaning without pre-cleaning.

In the main cleaning, it is preferable to use ultrasonic cleaning in combination with electrolytic cleaning, and the cleaning power can be further enhanced.
The ultrasonic cleaning is preferably performed by attaching an ultrasonic generator to the bottom surface of the cleaning tank and switching the ultrasonic vibrator to two or more frequencies to generate ultrasonic waves. As described above, when the ultrasonic vibration is not changed to a constant frequency but is switched to a different frequency, for example, 34 KHz and 44 KHz, and alternating ultrasonic vibration is generated, an appropriate stirring action can be generated in the electrolytic cleaning liquid, Detergency can be increased. Instead of ultrasonic waves, a single wave of 30 KHz to 100 KHz may be used.
When the mold to be cleaned is for a controllable molded product such as a light guide plate of a flat panel display, an ultra small precision lens, an automobile reflector, etc., and the mold is a nickel mold, the frequency of the ultrasonic wave is 30 KHz to 100 KHz, A range of 40 to 70 KHz is preferable. Within this range, the metal bonding balance on the nickel plating surface is not lost, and the nickel coating layer can be cleaned without damaging it.

After the pre-cleaning using the pre-cleaning liquid, the main cleaning using the main cleaning liquid, and / or the post-cleaning using the post-cleaning liquid, the cleaning liquid is removed by any of the following methods (1) to (3). ing.
(1) Only rinse with clean water.
(2) After rinsing with clean water, rinsing with alcohol, ethanol, acetone, or a mixture of these with water is performed.
(3) Rinse washing is performed directly with alcohol, ethanol, acetone, or a mixture of these with water without washing with water.
In this way, by removing the cleaning liquid, it is possible to prevent water stain on the mold surface from occurring due to the influence of the composition and impurities contained in the water of the cleaning liquid.

In the mold cleaning, the cleaning strength is changed according to the amount of resin residue adhering to the mold, the adhesive force, the adhesion position, the type of resin, etc. (1) to (5) are preferably selected.
(1) Main cleaning → Cleaning liquid removal
(2) Main cleaning → Cleaning liquid removal → Rust prevention treatment (3) Pre cleaning → Cleaning liquid removal → Main cleaning → Cleaning liquid removal → Rust prevention treatment (4) Main cleaning → Cleaning liquid removal → Post cleaning → Cleaning liquid removal → Rust prevention treatment (5 ) Pre-cleaning → Cleaning liquid removal → Main cleaning → Cleaning liquid removal → Post-cleaning → Cleaning liquid removal → Rust prevention treatment.
In the case of a nickel mold, (1) is preferable.

  Electrolytic cleaning Before the main cleaning, the pre-cleaning using the pre-cleaning liquid and / or the post-cleaning using the post-cleaning liquid after the main cleaning, the heat resistance, oil resistance, wear resistance that adheres firmly to the mold surface Can be reliably removed.

  Regardless of which process is used, the cleaning performance can be improved by using ultrasonic cleaning in combination with electrolytic cleaning, and the cleaning time can be adjusted according to the degree of mold contamination, and the main cleaning liquid and pre-cleaning. The components of the cleaning liquid for post-cleaning are adjusted within the above range.

  The water washing may be shower washing by discharging water from a nozzle or the like, or the mold may be immersed in a washing tank in which water is stored. In the rinse cleaning, the volatile component or a mixed solution of the volatile component and water may be applied to the mold from a nozzle or the like, or the mold may be immersed in a cleaning tank in which the liquid is stored.

After the post-cleaning, it is preferable to perform a rust prevention treatment by applying a rust preventive agent to the mold surface after removing the post-cleaning liquid. The rust prevention treatment is performed by immersing the mold in a liquid tank in which a rust inhibitor is stored, but other coating methods may be used.
An aqueous rust inhibitor made of a lower amine is used as the rust inhibitor, and morpholine is particularly preferably used.
In addition, in the nickel mold for the light guide plate, the plastic lens, and the reflector, it is preferable that the rust preventive treatment is not performed because the residue tends to remain on the nickel-coated surface.

As described above, when an aqueous rust inhibitor is used, it evaporates and volatilizes at around 100 ° C., and spontaneously evaporates in 2 to 3 days without heating, and the rust inhibitor adheres to a molded product molded with a mold. Can be prevented.
On the other hand, since the water-based rust preventive agent has a relatively short rust prevention period, if there is no problem even if the rust preventive agent adheres to the surface of the molded product, it can be replaced with the water-based rust preventive agent or the water-based rust preventive agent. The oil-based rust preventive agent may be applied again on the mold surface coated with the rust preventive agent.

  The present invention includes, as a third invention, a pre-cleaning tank for performing pre-cleaning and / or a post-cleaning tank for performing post-cleaning, and a main cleaning tank for performing main cleaning with an electrolytic cleaning means. A mold cleaning apparatus is provided in which the pre-cleaning liquid is supplied and the main cleaning tank is supplied with the main cleaning liquid.

  Furthermore, it goes without saying that a shower and a washing tank for rinsing with a volatile component for rinsing off the washing liquid and a rust prevention means may be additionally provided.

In the case of pre-cleaning, the mold is immersed in the pre-cleaning tank supplied with the pre-cleaning liquid for a required time.
As a cleaning tank for main cleaning that is also performed in combination with electrolytic cleaning, preferably ultrasonic cleaning, the cleaning apparatus described in Patent Document 1 and the like previously filed by the present applicant, Japanese Patent Application No. 2004-101361. The described cleaning device or the like is preferably used.

  The mold can be transported from the pre-cleaning tank to the main cleaning tank and from the main cleaning tank to the post-cleaning by holding the mold holder with the guide rail installed at the upper side. You may hold | maintain and convey with a holder.

  In particular, the pre-cleaning tank is provided with a lid that seals the top opening of the pre-cleaning tank during cleaning, and is provided with means for heating the auxiliary cleaning tank in a state of being sealed with the lid so that the auxiliary cleaning tank is pressurized. It is preferable to have a hook configuration.

  When the mold to be cleaned is a precision mold for flat panel display light guide plates, lenses, automobile reflectors, etc., and is a nickel mold, as described above, there is no pre-cleaning in the main cleaning tank. It is most preferable to use a cleaning method in which electrolytic cleaning and ultrasonic cleaning are used in combination using the cleaning solution. When the cleaning method is used, it is possible to obtain the most demanding cleaning performance including prevention of adhesion of ultrafine particles and removal of attached ultrafine particles.

When cleaning the nickel mold, the positive electrode used for electrolytic cleaning of the main cleaning tank is platinum (platinum), palladium, rhodium, iridium, ruthenium, osmium, gold, silver noble metals, Alternatively, it is preferable to use one or a plurality of these precious metal alloys or to be plated with the metal.
Furthermore, it is preferable that the electrode on the positive electrode side is formed by plating or pasting the metal on titanium.
Furthermore, it is preferable that the voltage applied to the electrode for electrolytic cleaning of the main cleaning tank is in the range of 2 to 5V.

As described above, according to the present invention, the cleaning liquid is not a cleaning liquid containing an organic solvent, but a nonionic, cationic or anionic surface active as a pre-cleaning liquid before the main cleaning for electrolytic cleaning (preferably combined with ultrasonic cleaning). Since the pre-cleaning is performed using a cleaning liquid containing an agent, sodium metasilicate or / and sodium orthosilicate, and a chelating agent, the resin having heat resistance, oil resistance, and abrasion resistance is formed on the mold surface, particularly on the fine recesses. Even when the resin is adhered to the corner, it is possible to surely remove those that could not be removed by conventional electrolysis or / and ultrasonic mold cleaning.
Furthermore, in the case of a mold with severe dirt, the post-cleaning liquid of the same component as the pre-cleaning liquid is used, and after the main cleaning by electrolytic cleaning and ultrasonic cleaning, the post-cleaning removes the resin residue that is difficult to remove. be able to.

In addition, the main cleaning solution for electrolytic cleaning is a strong alkali component containing at least one selected from sodium hydroxide, potassium hydroxide, and sodium carbonate, a chelating agent composed of EDTA tetrasodium salt, and an oxidation composed of organic nitrogen or inorganic nitrogen. Water containing an object removing component and sodium gluconate is used, and the water is purified by a purification means to remove foreign matters such as silica and calcium contained in tap water. Therefore, when the mold to be cleaned with the electrolytic cleaning solution is a nickel mold for forming a precision part, it should be cleaned with an excellent cleaning power that does not have foreign matter attached even when observed with an electron microscope of 1000 to 10000 times. Can do.
Therefore, when cleaning a nickel mold for forming a light guide plate, a lens, an automobile reflector or the like of a flat panel display, it can be effectively used due to its high cleaning ability.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
FIG. 1 is an overall schematic view of a mold cleaning apparatus according to the first embodiment, where 10 is a pre-cleaning tank, 11 is a water-washing tank, 12 is a main cleaning tank, 13 is a rinsing tank, and 14 is a rust-proof coating tank.
The mold cleaned by the cleaning device of the first embodiment is not a nickel-coated nickel mold but a general steel mold.
Among the cleaning tanks, the pre-cleaning tank 10 and the main cleaning tank 12 include lids 16 and 17 that close the upper surface openings of the cleaning tanks 10 and 12, and are closed and cleaned with these lids 16 and 17 during cleaning. Yes.
In addition, the said lid | cover is good also as one continuous lid, without providing in each tank separately. Moreover, although it may wash | clean without sealing with a cover, it is preferable to pre-clean the pre-cleaning tank 10 with the cover 16 sealed.

The cleaning tanks 10 to 14 are arranged side by side, a guide rail 20 is mounted on the upper part of the cleaning tanks 10 to 14, and a metal holding basket 22 that holds a mold 21 for synthetic resin to be cleaned is armed. 23 is detachably attached and sequentially conveyed.
In addition, the said conveyance mechanism is not necessarily required, The operator may insert the holder which hold | maintains a metal mold | die into a washing tank sequentially.

The pre-cleaning tank 10 has a box shape with an upper surface opening, and stores a pre-cleaning liquid Q1 in the inside. As shown in FIG. 22 is immersed, and the required time (preferably 15 minutes to 30 minutes) is immersed.
The pre-cleaning liquid Q1 is obtained by blending nonionic, cationic or anionic surfactant, sodium metasilicate or / and sodium orthosilicate, and a chelating agent in water. The water is pure water obtained by purifying tap water by a purification means.
In the pre-cleaning liquid Q1 of this embodiment, 2 cc / liter of surfactant, 50 g / liter to 100 g / liter of sodium metasilicate, and 100 g / liter to 50 g / liter of a chelating agent composed of sodium EDTA are mixed, and the rest It's water.

  The pre-cleaning tank 10 is provided with a heating means 18 comprising a heater or the like in the lower part thereof, and at the time of cleaning, the upper opening of the pre-cleaning tank 10 is closed with a lid 16 to form a pressure cooker. In this state, the pre-cleaning liquid Q1 in the pre-cleaning tank 10 is boiled with the heating means 18, and the mold 21 is pre-cleaned with the pre-cleaning liquid Q1.

  After the pre-cleaning in the pre-cleaning tank 10, a water-washing tank 11 for washing the mold is provided to wash off the pre-cleaning liquid adhering to the mold surface. In this water rinsing tank 11, water is poured from a shower 15 arranged at the upper part to easily wash the mold. In addition, you may immerse in the tank which stored clean water and wash with water.

The mold washed in the water washing tank 11 is transferred to the main washing tank 12 shown in FIGS. The main cleaning tank 12 is configured to perform cleaning using both an electrolytic cleaning method and an ultrasonic cleaning method.
The main cleaning tank 12 has a box shape with an upper surface opening, and a planar heater (not shown) made of a silicon rubber heater is attached along substantially the entire outer peripheral surface of the main cleaning tank 12, and the main cleaning liquid Q2 in the main cleaning tank 12 is 30-60. Heat to ℃.

This cleaning liquid Q2 (that is, electrolytic cleaning liquid) is composed of a strong alkali component containing one or more selected from sodium hydroxide, potassium hydroxide, and sodium carbonate, a chelating agent composed of EDTA tetrasodium salt, and organic nitrogen or inorganic nitrogen. One or more surfactants selected from an oxide removal component, sodium gluconate, and nonionic, cationic, and anionic surfactants are blended in pure water obtained by purifying tap water by a purification means. .
At that time, the compounding amount is 30-100 g / liter of strong alkali component, 30-100 g / liter of EDTA tetrasodium salt, 10-60 g / liter of sodium gluconate, 30-150 g / liter of the oxide removing component, One or more surfactants selected from nonionic, cationic, and anionic surfactants are added to 1 to 3 cc / liter, and the remainder is added as pure water.

  The main cleaning liquid Q2 is stored in the main cleaning tank 12 up to a required level according to the amount of the mold 21, and is circulated from an outlet provided on the bottom wall of the main cleaning tank 12 when necessary. After being discharged into a pipe, guided into the purification tank, filtered, sucked up by a circulation pump, and introduced into the upper surface opening of the main cleaning tank 11 for circulation.

An insulating base 21 is attached to the upper surface of the outer peripheral flange portion surrounding the upper surface opening of the main cleaning tank 12, and the support arm 22 a of the holding cage 22 of the mold is suspended from the insulating base 21 to The holding basket 22 is detachably suspended and the basket 22 is prevented from contacting the bottom surface and the inner peripheral surface of the main cleaning tank 12.
The mold holding basket 22 has a support arm 22a protruding from a bottom portion 22b made of punching metal, and an upper refracting portion 22c provided on the support arm 22a is mounted on the insulating base 21. At that time, some support arms 22a are positioned and placed on a stainless steel power supply plate 23 mounted on two opposing sides of the insulating base 21. The support arm 22a of the mold holding basket 22 is provided with an insulation coating so as not to be energized by contacting the inner surface of the cleaning tank 12, and only the contact portion with the power supply plate 23 is not provided with an insulation coating.

The feeding plate 23 is fixed to the insulating base 21 with a long energizing bolt (not shown) penetrating the insulating base 21, and the lower end of the energizing bolt is connected to the negative electrode of the converter for electrolysis via a bus bar. doing.
Similarly, a similar power supply plate 27 is mounted on the other two opposite sides of the insulating base 21, and a conductive support rod 28 is pivoted between the power supply plates 27, and the power supply plate 27 is connected via a bus bar. It is connected to the positive electrode of the exchange air for electrolysis.

  The conductive support rods 28 are provided with mounting holes 28a at regular intervals in the length direction, and the lower ends of the upper longitudinal axes 29a are bifurcated in the lateral direction into the mounting holes 28a. Is bent downward, and an electrode material 29 having a circular electrode plate 29c attached to the lower end thereof so as to be swingable is attached so that the vertical length can be adjusted, and the electrode plate 29c is suspended in parallel with an interval from the conductive support rod 28. Is not in contact with the mold and the holding basket 22.

  The electrolysis converter is connected to an AC power supply, converts current from AC to DC, and supplies current to the electrode and the mold holding cage 22 for electrolytic cleaning. In this way, by connecting the electrode material 29 to the plus side of the electrolysis converter and the mold holding basket 22 to the minus side, the electrolysis cleaning is performed by energizing the main cleaning liquid Q2 made of an electrolytic cleaning liquid. I am doing so.

  Further, a vibrator (not shown) that generates ultrasonic waves for performing ultrasonic cleaning is attached to the bottom surface of the main cleaning tank 12 so as to generate ultrasonic vibrations in the main cleaning liquid Q2 in the main cleaning tank 12. I have to.

In the main cleaning tank 12, after the main cleaning liquid is heated to a required temperature, the power is supplied to the mold holding basket 22 and the electrode material 29 from the power supply plates 23 and 27, and is held in the mold holding basket 22 through the main cleaning liquid Q2. In addition to performing electrolytic cleaning of the mold 5, ultrasonic cleaning is also used to generate ultrasonic vibration.
In the main cleaning tank using both the electrolytic method and the ultrasonic cleaning method, the ultrasonic cleaning method applies vibrations to the deposits such as the resin residue from the outside of the mold 21 to destroy the deposits. The deposits are lifted from the mold 21 by the hydrogen gas generated from the metal mold surface by the cleaning method, and the deposits are peeled off from the mold 21 and removed. And in that case, since this cleaning liquid Q2 is required heating, strong cleaning power can be exhibited.

  The mold 21 that has been subjected to main cleaning in the main cleaning tank 12 is conveyed to the rinsing tank 13. This rinsing tank 13 is provided with a shower 19, and a rinse solution is applied by applying a mixed solution of ethanol and water in a state where the mold is held on the holding basket 22. In the present embodiment, rinsing is performed with a mixture of alcohol and water.

After rinsing and washing in the rinsing tank 13, it is transferred to the rust prevention treatment tank 14. An aqueous rust inhibitor Q3 made of a lower amine is stored in the rust prevention treatment tank 14, and a mold 21 held by a holding basket 22 is immersed in the rust prevention treatment tank 15, so that the surface of the mold 21 is immersed. A water-based rust preventive agent is applied.
In the present embodiment, morpholine is used as an aqueous rust inhibitor made of a lower amine.
In addition, if the resin molded product shape | molded with a metal mold | die is a product with which a rust preventive agent may adhere to the surface, it is further immersed in the 2nd rust prevention processing tank which stored the oil-based rust preventive agent.

According to the above-described embodiment, the mold to be cleaned is first cleaned with the pre-cleaning liquid Q1 in the pre-cleaning tank 10, and then the main cleaning is performed after the pre-cleaning liquid Q2 is rinsed with clean water in the water cleaning tank 11. The main cleaning is performed with the main cleaning solution Q2 in the tank 12 using both electrolytic cleaning and ultrasonic cleaning.
At that time, the resin residue adhering to the mold 21 in the pre-cleaning with the pre-cleaning liquid Q1, the electrolytic cleaning with the main cleaning liquid Q2, and the ultrasonic cleaning is a resin having heat resistance, oil resistance, and wear resistance. Even if it adheres to the corners of the fine recesses, it can be reliably removed and the cleaning ability can be enhanced.

  The mold cleaning apparatus of the present invention is not limited to the above-described embodiment, and is disclosed in Japanese Patent Application Laid-Open No. 2004-101361 according to the prior application of the present applicant as a main cleaning tank that uses both electrolytic cleaning and ultrasonic cleaning. A cleaning apparatus shown in FIG.

  Moreover, this cleaning tank is good also as a structure shown in FIG. In the main cleaning tank 35, a side plate 31 made of resin is erected in a square frame shape on a bottom plate 30 made of a conductive metal plate, and a mold 21 is directly placed on the bottom plate 30, and the mold is moved from the bottom plate 30 to the mold. Energized. The electrode 29 is suspended on the side wall 31 in the same manner as in the above embodiment. The main cleaning liquid Q2 is supplied into the cleaning tank 35 constituted by the bottom plate 30 and the side plate 31.

The first embodiment includes the steps shown in FIG. That is, it consists of pre-cleaning with pre-cleaning liquid → water cleaning with clean water → main cleaning by electrolytic cleaning and ultrasonic cleaning → rinsing cleaning with ethanol / water mixture → anti-rust coating, and post-cleaning with post-cleaning liquid is omitted. Yes.
The washing step is not limited to the above (A), and as shown in (B), after the pre-washing, after rinsing with clean water, rinse with ethanol alone to completely remove the pre-washing solution, and then perform the main washing. May be.

In the first embodiment, the post-cleaning with the post-cleaning liquid is not performed. However, in the case where the resin residue of the mold is not easily removed, as shown in FIG. After the post-cleaning liquid is filled, the post-cleaning is performed by dipping in a cleaning tank. It is preferable that the post-cleaning is heated to such an extent that the post-cleaning liquid is boiled as in the pre-cleaning. After washing with the post-cleaning liquid, washing with clean water and then rinsing with ethanol alone are performed.
In FIG. 6D, after the post-cleaning with the post-cleaning liquid, the water cleaning is omitted, and the rinse cleaning with the mixed liquid of ethanol and water is performed.

Further, as shown in FIGS. 7A and 7B, the pre-cleaning with the pre-cleaning liquid may be omitted.
In FIG. 7A, main cleaning → rinse cleaning with a mixed solution of ethanol and water → rust prevention coating is performed.
In FIG. 7B, post-cleaning with post-cleaning liquid is performed, main cleaning → washing with cleaning liquid → post-cleaning with post-cleaning liquid → water cleaning with cleaning liquid → rinse cleaning with ethanol alone → rust prevention coating.

  Further, as shown in FIG. 7C, main cleaning → water washing → rinse cleaning, and main cleaning → water washing → drying as shown in FIG. FIG. 7D is suitable for cleaning a nickel mold for molding the light guide plate and the lens.

  The second embodiment of the present invention cleans a nickel mold for forming a light guide plate of a flat display. 7D is the main cleaning → water washing → drying step, and the nickel mold is placed on the mold holding basket 22 shown in FIG. 2 in the cleaning tank 12 shown in FIGS. 3 and 4 shown in the first embodiment. It is mounted and washed. Therefore, the illustration of the cleaning device of the second embodiment is omitted, and will be described with reference to FIGS.

In the cleaning tank 12, the main cleaning liquid Q2 is supplied. The water blended in the main cleaning liquid is obtained by distilling tap water.
The electrode plate 29c attached to the lower end of the electrode material 29 suspended for electrolytic cleaning in the main cleaning tank 12 uses a titanium surface coated with platinum, and is applied between the electrode plate 29c and the mold holding basket 22. The voltage to be set is about 5V.
Further, the vibration frequency of the ultrasonic vibrator arranged on the bottom surface of the main cleaning tank 12 is set in the range of 40 to 70 KHz.

In the second embodiment, since the mold is easily damaged by the nickel mold, the mold is not transported for water washing and drying after the main cleaning, and remains immersed in the cleaning tank 12, and after the main cleaning. The main cleaning liquid is discharged, and water for washing is supplied to the cleaning tank 12 after discharging.
After the water supply for washing is repeated about twice, alcohol or acetone is sprayed on the mold under a required pressure and dried.

In the second embodiment, when the nickel mold is cleaned in the main cleaning tank 12 by using both electrolytic cleaning and ultrasonic cleaning, the surfactant contained in the cleaning liquid Q2 contains metal fine particles and resin fine particles on the nickel-coated surface. A barrier that suppresses adhesion is built up to prevent foreign particles such as metal particles from adhering.
Further, since the electrode material 29 is made of platinum, the amount of precipitation is reduced, and furthermore, the frequency of ultrasonic vibration is set to 40 to 70 KHz so as not to break the balance of metal bonding of the nickel plating layer. Damage can be prevented from occurring.
Therefore, it is most suitable for cleaning nickel molds for fine resin molded products such as light guide plates for flat panel displays, ultra-small and precise camera lenses such as mobile phones, and reflectors (light reflectors) for vehicles. .

The cleaning liquid, the cleaning method, and the cleaning apparatus according to the present invention are not limited to the synthetic resin mold described in the embodiment, and can be suitably used for cleaning molds for rubber molding, glass molding, and the like.
Further, when used for cleaning a nickel mold for forming a precision molded product such as a light guide plate of a flat display, the cleaning ability with high accuracy can be exhibited. Therefore, advanced precision products such as CD-ROM, DVD-ROM, spar multi-drive RAM, HDDVD pickup lens, Blu-ray disc pickup lens, liquid display hologram prism, digital camera liquid hologram prism, mobile phone CCD camera lens It can be suitably used for cleaning precision part molding dies for molding various light guide plates and the like.

1 is an overall schematic diagram of an embodiment of the present invention. It is a perspective view which shows the holding basket of a metal mold | die. It is a top view which shows this cleaning apparatus. FIG. 4 is a perspective view of FIG. 3. It is sectional drawing of other embodiment. (A)-(D) are drawings which show a washing process. (A)-(D) are drawings which show another washing process. It is drawing which shows a prior art example. It is drawing which shows another prior art example.

Explanation of symbols

10 Pre-cleaning tank 12 Main cleaning tank 13 Rinse tank 14 Rust prevention tank 21 Mold 22 Holding basket Q1 Pre-cleaning liquid Q2 Main cleaning liquid Q3 Water-based anti-corrosion agent

Claims (26)

  A cleaning solution used for pre-cleaning before and / or post-cleaning after electrolytic cleaning, and nonionic, cationic or anionic surfactant, sodium metasilicate or / and sodium orthosilicate, and chelating agent. A mold cleaning liquid characterized by containing.   The mold cleaning liquid according to claim 1, wherein the pre-cleaning liquid and / or the post-cleaning liquid is heated to about 40 ° C to 100 ° C.   This cleaning solution for electrolytic cleaning is a strong alkaline component containing at least one selected from sodium hydroxide, potassium hydroxide and sodium carbonate, a chelating agent consisting of EDTA tetrasodium salt, and an oxidation consisting of organic nitrogen or inorganic nitrogen The metal mold | die washing | cleaning liquid characterized by including a thing removal component and sodium gluconate. As the inorganic nitrogen, nitrate or ammonia salt is used,
As the organic nitrogen, ethylenediamine selected from ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenebexamine,
The gold according to claim 3, wherein hydroxyethyliminodiacetic acid sodium salt, nitrilotricetecate-3sodium (NTA.3Na), dicarboxymethyl-glutamic acid tetrasodium-4sodium (GLDA.4Na) is used as the chelating agent. Mold cleaning solution.   The mold cleaning liquid according to claim 3 or 4, comprising one or more surfactants selected from nonionic, cationic and anionic surfactants.   6. The gold according to any one of claims 1 to 5, wherein tap water is mixed with water from which impurities are removed through purification means in the cleaning liquid used in the main cleaning, pre-cleaning and / or post-cleaning. Mold cleaning solution.   7. The mold cleaning liquid according to claim 6, wherein a purification means employing distillation, ion exchange or / and filtration is used as the purification means.   30 to 100 g / liter of the strong alkali component, 30 to 100 g / liter of the EDTA4 sodium, 10 to 60 g / liter of sodium gluconate, and 30 to 150 g / liter of the oxide removing component composed of organic nitrogen or inorganic nitrogen. The mold cleaning liquid according to any one of claims 3 to 7.   The mold cleaning liquid according to claim 8, wherein 1 to 3 cc / liter of one or more surfactants selected from the nonionic, cationic, and anionic surfactants are blended.   The mold cleaning liquid according to any one of claims 3 to 9, wherein the cleaning liquid used for the main cleaning is heated to about 30 ° C to 60 ° C.   A mold cleaning method using the cleaning liquid according to any one of claims 3 to 10 at the time of main cleaning in electrolytic cleaning.   3. A mold cleaning method using the cleaning liquid according to claim 1 or 2 for pre-cleaning before main cleaning of electrolytic cleaning and / or post-cleaning after main cleaning of electrolytic cleaning.   The mold cleaning method according to claim 11 or 12, wherein ultrasonic cleaning is used in combination with the main cleaning.   The mold cleaning method according to claim 13, wherein a frequency of the ultrasonic cleaning is in a range of 30 KHz to 100 KHz. After the pre-cleaning using the pre-cleaning liquid, the main cleaning using the main cleaning liquid, and / or the post-cleaning using the post-cleaning liquid, the cleaning liquid is removed by any of the following methods (1) to (3). The mold cleaning method according to claim 11 to 14.
(1) Only rinse with clean water.
(2) After rinsing with clean water, rinsing with alcohol, ethanol, acetone, or a mixture of these with water is performed.
(3) Rinsing with alcohol, ethanol, acetone, or a mixture of these and water is directly performed without washing with water. The mold cleaning method according to claim 11, wherein the cleaning step is selected from the following (1) to (5).
(1) Main cleaning → Cleaning liquid removal
(2) Main cleaning → Cleaning liquid removal → Rust prevention treatment (3) Pre cleaning → Cleaning liquid removal → Main cleaning → Cleaning liquid removal → Rust prevention treatment (4) Main cleaning → Cleaning liquid removal → Post cleaning → Cleaning liquid removal → Rust prevention treatment (5 ) Pre-cleaning → Cleaning liquid removal → Main cleaning → Cleaning liquid removal → Post-cleaning → Cleaning liquid removal → Rust prevention treatment.   17. The mold cleaning method according to claim 16, wherein the rust prevention treatment is performed by applying a rust inhibitor to the mold surface, and an aqueous rust inhibitor composed of a lower amine is used as the rust inhibitor.   The mold cleaning method according to claim 17, wherein morpholine is used as the lower amine.   19. The mold cleaning method according to claim 12, wherein the cleaning tank is covered and sealed at the time of the pre-cleaning and heated to about 40 ° C. to 100 ° C. 19.   A cleaning tank for performing at least pre-cleaning and / or post-cleaning and a main cleaning tank for performing main cleaning with an electrolytic cleaning means are provided, and the cleaning tank for pre-cleaning and / or post-cleaning is defined in claim 1 or claim 2. A mold cleaning apparatus, wherein the main cleaning liquid according to any one of claims 3 to 10 is supplied to the main cleaning tank.   The said pre-cleaning tank is provided with the lid | cover which seals the upper surface opening of a pre-cleaning tank at the time of washing | cleaning, and the means to heat the said pre-cleaning tank in the state sealed with this lid | cover is provided. Mold cleaning equipment. The mold to be cleaned in this cleaning tank having at least electrolytic cleaning means and ultrasonic cleaning means is a nickel plating mold, a nickel alloy plating mold, a nickel plate surface application mold, a nickel alloy plate surface application mold or nickel. A nickel mold consisting of a mold formed of
A mold cleaning apparatus, wherein the main cleaning liquid according to any one of claims 3 to 10 is supplied to the main cleaning tank.   The mold cleaning apparatus according to claim 22, wherein the nickel mold is a mold for injection molding of a light guide plate of a flat panel display, a mold for injection molding of a lens, or a mold for injection molding of a vehicle reflector. .   The electrode on the positive electrode side used for electrolytic cleaning of the main cleaning tank is one or more of platinum (platinum), palladium, rhodium, iridium, ruthenium, osmium, gold, silver noble metals, or alloys of these noble metals. The mold cleaning apparatus according to claim 22 or 23, which is made of a seed metal or a metal plated with the metal.   The mold cleaning apparatus according to claim 24, wherein the positive electrode is made of titanium plated with the metal.   The mold cleaning apparatus according to any one of claims 22 to 25, wherein a voltage applied to an electrode for electrolytic cleaning in the main cleaning tank is in a range of 2 to 5V.

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