JPS58223471A - Cleaning method and apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for cleaning molds for plastics, particularly styrene resins.

Audio and VTR cassette cases are mainly made of styrene resin, but this product
High dimensional accuracy is required, and accordingly, the precision of molds has also become extremely high. On the other hand, in recent years, various innovations have been made to shorten the molding cycle, and the gases generated during injection molding, mainly composed of oligomers and various additives, cannot be fully released outside the mold, and mold gas vents, inserts, etc. It condenses and remains in the small gaps between mold components, causing contamination of the molded product.

In order to avoid these problems, molding companies are considering various ways to clean the molds, but conventionally, the cloth is impregnated with a solvent or activator while the mold is still in the molding machine. The common method was to wipe it by hand, or to remove the mold from the molding machine, disassemble everything, including the small inserts, and wipe it by hand in the same way.

However, the former method does not allow complete cleaning, and the latter method requires a great deal of time and effort, and both are extremely unsatisfactory.

The present invention provides a novel process in which such molds are simply disassembled into rough plate shapes, and the molds can be reliably and efficiently cleaned while still assembled, and even drying and cooling can be performed consistently. The company provides a device, the gist of which is a cleaning tank equipped with an ultrasonic oscillator, which uses a chlorinated solvent to
℃ to the -boiling point of the solvent, and then rotated in space at least 180 degrees with respect to the horizontal plane to flush out the residual solvent, and then, while the items to be washed are held in the space of the box, Suction of air inside the box/(or blowing air into the box)
A mold cleaning method characterized by completely removing the solvent remaining in the small gaps in gaseous form and cooling the object to be cleaned at the same time. It consists of a cleaning tank equipped with an ultrasonic oscillator and a liquid storage tank connected to the bottom of the cleaning tank via a valve. A device for cleaning, drying, and cooling plastic molds, characterized by being equipped with a suction/exhaust/(or air blow/exhaust) line.

In the cleaning method of the present invention, the mold to be washed is simply divided into a core side and a cavity side, and a complicated mold is divided into plate shapes, and the nested part and protruding bottle are separated. , it can be put into the cleaning tank while being fixed to the board. The cleaning liquid is a chlorinated solvent that is nonflammable and can dissolve styrene resins and the additives contained therein, especially 1,1
．． 1-) Lichloroethane or trichlorethylene is
It can be used well. The cleaning tank must be equipped with an ultrasonic oscillator in order to infiltrate the solvent into the small gaps in the mold and obtain a good cleaning effect. The properly segmented molds are cleaned in a cleaning solution at temperatures between 40° C. and the boiling point of the solvent when exposed to ultrasonic waves.

Although it is preferable for the temperature of the solvent to be high in order to remove dirt, once the solvent reaches its boiling point, the cavitation effect of the ultrasonic waves is diminished by convection of the liquid. Therefore, temperature conditions should be selected depending on the type and degree of dirt on the item to be washed.

Usually, dirt is completely removed by ultrasonic cleaning for 10 to 30 minutes. Thereafter, the items to be washed are lifted out of the solvent (or the solvent is drained from the washing tank) and held in the tank space, and the residual solvent is removed by rotating at least 180° relative to the water transport surface. This is a major feature of the present invention. This is because the mold has cold water holes for cooling.
The liquid runs in multiple directions, making it extremely difficult to remove the liquid after cleaning.
It has been discovered that the above-mentioned method can easily and reliably remove liquid. In this state, the solvent that can be discharged and removed is almost completely removed, but a small amount of adhering solvent still remains in small gaps between the inserts, gas vents, etc.

Furthermore, the mold immediately after cleaning has been heated to a temperature close to the cleaning temperature, and its dimensions have changed due to thermal expansion, so it cannot be assembled immediately. In order to remove a small amount of adhering solvent and lower the mold temperature in a short time, a blower is used to suck in air from the tank holding the mold, or blow cooling air. Molds are generally heavy and have a large heat capacity, so it is difficult to cool them in a short period of time, but in this way, the adhering solvent takes away the heat of vaporization and speeds up the cooling rate, making drying and drying very efficient. Cooling takes place at the same time.

In the present invention, in order to increase cleanliness, shower cleaning and steam cleaning are used in combination after ultrasonic cleaning.

There is no problem with that. Also, drain the liquid after washing and dry (cool)
may be carried out in the same cleaning tank or in separate tanks.

Next, the apparatus of the present invention will be explained with reference to the drawings. FIG. 1 shows an example of the integrated washing-drying-cooling apparatus of the present invention. In Fig. 1, 1 is a washing tank, 2 is a liquid storage tank, 3 is a valve that connects both tanks and the exhaust line, 4 is an ultrasonic oscillator, and 5 is a device that can rotate by gripping the object to be washed. The jig is shown.

Also, 6 is a pump that transfers the solvent from the liquid storage tank to the cleaning tank, 7 is an exhaust blower, 18 is a water separator, 9 is a heater for heating, 10.12 is a cooling coil, and 11 is a cleaning tank. 13 shows the lid of the washing machine held by the jig, and 1
4 indicates the liquid level of the solvent.

In the present invention, the jig may be a fixed type as shown in the figure, or an elevating type.

Further, a chiller or an activated carbon adsorption device can be inserted in the middle of the exhaust line to recover solvent vapor, or a heater can be inserted to circulate heated air. Although a heater is not necessarily required in the liquid storage tank 2, if the temperature of the solvent is raised in advance here, the cleaning cycle can be made shorter.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A VTR cassette case was molded using an acrylonitrile/butadiene/styrene copolymer as a raw material. After molding 150,000 shots, the mold was removed from the molding machine and disassembled into plate shapes. The part with the highest degree of contamination is the template on the core side.
This was subjected to cleaning with the guide pin, back plate, and numerous inserts still attached. The washing machine used was the one shown in Figure 1, and the solvent was I,1.1-)lichloroethane (
Chlorocene VG) manufactured by Asahi Dow Co., Ltd. was used.

First, the template was hoisted up using an electric hoist (not shown), carried into a cleaning tank containing no solvent, and fixed to a rotating jig.

Thereafter, chlorocene VG previously heated to 60°C was poured into the cleaning tank from the storage tank, and cleaning was started. The cleaning is
28 KHl,] KW's ultrasonic oscillator was operated for 15 minutes, and after completion, the solvent was transferred to a storage tank. Thereafter, the handle of the rotating jig was operated to slowly rotate it three times, and the valve 3 was operated to open the exhaust line. The blower was operated to perform drying and cooling for 30 minutes, and the template was taken out. After cleaning, the template was thoroughly cleaned, including the gaps between the inserts, and could be assembled and used immediately by simply adding a small amount of oil to the guide bottle. With conventional hand wiping or regular cleaning, it was necessary to disassemble and clean even the nesting part.
It takes a lot of time to disassemble and assemble, and only cleaning the template is enough.
However, the present invention has made it possible to significantly improve productivity.

[Brief explanation of the drawing]

The figure shows an example of the washing/drying/cooling device of the present invention. In Fig. 1, 1 is a cleaning tank, 2 is a liquid storage tank, 3 is a valve that connects both tanks and the exhaust line, 4 is an ultrasonic oscillator, and 5 is a device that can grip and rotate the items to be washed. Indicate the ingredients. Further, 6 indicates a solvent transfer line including a transfer pump, and 7 indicates a suction exhaust/(or air blow-exhaust) line including an exhaust blower. Applicant Asahi Dow Co., Ltd. Agent Yutaka 1) Yoshio Procedural Amendment (July 31, 1980 Kazuo Wakasugi, Commissioner of the Japan Patent Office) Indication of Case Patent Application No. 106688/1982 2, Method for Cleaning Name of Invention and Device 3, Person making the amendment Relationship with the case Patent applicant 1-1-2 Yurakucho, Chiyoda-ku, Tokyo (046) Asahi Dow Co., Ltd. Representative Rei Yumikura - 4, Agent 1 Yurakucho, Chiyoda-ku, Tokyo Room 204, Sanshin Building, 4-1 Chome Telephone: 501-21385, Subject of Amendment 6 Contents of Amendment 6-1 The scope of claims in the specification will be corrected as shown in the attached sheet. 6-2 Delete 1 in the range from 40°C to the boiling point of the solvent on lines 12-13 on page 3 of the specification cylinder. 6-3 Insert the following sentence after the 5th line on page 4. ``The present invention is suitably used for mold cleaning of styrene-based resins, but in the present invention, styrene-based resins include polystyrene, styrene/acrylonitrile copolymers, styrene/acrylonitrile copolymers,
Includes butadiene/acrylonitrile copolymer and the like. ” 6-4 Delete “or” on page 4, line 13. 6-5 "Methylene chloride or perchlorethylene" after "trichlorethylene" on page 4, line 13
Insert. 6-6 ``Tetara j'' on page 4, line 18
I am corrected. 6-7 Delete "Between 140°C and the boiling point of the solvent" on page 4, line 18. 6-8 Insert "at a temperature between 40°C and the boiling point of the solvent" after "1 Normal" on the third line of page 5. 6-9 Insert "Rotate the mold even during cleaning" after "To improve cleanliness" on page 6, line 7. 6-10 1 on page 6, line 9 is correct. "After the"
In particular, shower cleaning at room temperature is effective in shortening the mold cooling time. Claims (1) Cleaning using a chlorinated solvent in a cleaning tank equipped with an ultrasonic oscillator, and subsequently cleaning the articles in a space for at least 18
Rotate 0° to flush out the remaining solvent, then, while keeping the items to be washed in the space inside the box, suck the air inside the box (or blow air into the box) and fill in the small gaps. A plastic mold cleaning method characterized by completely removing residual solvent in gaseous form and cooling the object to be cleaned at the same time. (2) The cleaning method according to claim 1, wherein the plastic mold is a styrene resin mold. (3) Consists of a cleaning tank equipped with an ultrasonic oscillator and a liquid storage tank connected to the bottom of the cleaning tank via a valve.The cleaning tank is equipped with a jig that can rotate while holding the items being washed. A cleaning, drying, cooling and penetrating device for plastic molds, characterized in that a suction/exhaust/(or air blow-exhaust) line is attached. Procedural amendment August 27, 1982. Mr. Kazuo Wakasugi, Director General of the Patent Office, 1, Indication of the case, Patent Application No. 1988-106688, 2, Invention name cleaning method and device, 3, Person making the amendment, relationship with the case, and patent applicant, Yurakucho, Chiyoda-ku, Tokyo, 1. Chome 1-2 (04fl) Asahi Dow Co., Ltd. Representative Rei Yumikura -4, Agent Sanshin Building Room 204, 1-4-1 Yurakucho, Chiyoda-ku, Tokyo Telephone 501-2138 Toyota Naigai Patent Office 6° Amendment On page 2, lines 12 to 15 of the description of contents, ``The molding cycle has been shortened, and gases mainly composed of oligomers and various additives generated during injection molding cannot be fully released outside the mold.'' Cycles are becoming shorter. During injection molding,
Although the low boiling point components contained in the resin are vaporized, 1. The vaporized gas could not be completely released outside the mold,'' he corrected.

Claims (3)

[Claims] (1) Cleaning using a chlorinated solvent in a cleaning tank equipped with an ultrasonic oscillator at a temperature ranging from 40°C to the boiling point of the solvent, and then rotating the washed item at least 180° in a space to remove any residue. The solvent is poured out, and then, while the items to be washed are held in the space inside the box, the air inside the box is sucked/(or air is blown into the box) to remove the solvent remaining in the small gaps in a gaseous state. A method for cleaning plastic molds, which is characterized by completely removing the mold and cooling the object to be cleaned at the same time. (2) The cleaning method according to claim 1, wherein the plastic mold is a styrene resin mold. (3) Consists of a cleaning tank equipped with an ultrasonic oscillator and a liquid storage tank connected to the bottom of the cleaning tank via a valve. A device for cleaning, drying, cooling, and penetrating plastic molds, characterized in that it is equipped with a suction/exhaust/(or air blow-exhaust) line.