JPH0910715A - Cleaning method - Google Patents

Abstract

PURPOSE: To remove minute foreign matter and oil particles sticking to the surface of a commodity easily and in a short time. CONSTITUTION: A liquid- or gas-phase hexamethylcyclotrisiloxane is caused to adhere to the surface of a commodity, then the adhering hexamethylcyclotrisiloxane is coagulates at normal temperature and the coagulation is air-cleaned. when hexamethylcyclotrisiloxane is coagulated, the coagulation contains foreign matter sticking to the surface of a commodity as a nucleus, and can be easily blown off the surface of a commodity at the time of later air-cleaning. Hexamethylcyclotrisiloxane is coagulated in a shorter time than is water and at normal temperature, as the coagulation point of the former is at 64.5 deg.C, and also removes an oil stain, as the former is soluble in oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning method for cleanly cleaning articles in which the attachment of extremely fine foreign matter is not permitted.

[0002]

2. Description of the Prior Art For precision equipment and parts in the medical field, there are several tens of thousands.
Even if a minute foreign substance of about μm to several hundreds of μm is attached, the degree of cleaning may be insufficient, and a strict cleaning process is required. For such strict cleaning, the cleaning method described in Japanese Patent Application Laid-Open No. 5-104072 is conventionally known. In this cleaning, moisture is attached to the surface of the article, the attached moisture is frozen, and air cleaning is performed at room temperature.

[0003]

Since the above-mentioned cleaning method freezes the water, the temperature of the article is 0, which is the freezing point of water.
It is necessary to cool below ℃. Therefore, it takes time, and the process time from cleaning to drying becomes long. Further, when air cleaning is performed at room temperature, some of the ice melts, and this melting easily causes water stains on the article surface. Further, when the used water is recovered, there is a problem that a part of the ice is melted and the water is scattered to reduce the recovery rate of the ice or the water. Further, since water has no oil solubility, when insoluble oil stains are present on the surface of an article, foreign matter can be removed but oil stains cannot be sufficiently removed. .

The present invention has been made in view of the above problems of the prior art, and the object of claim 1 is to use liquid hexamethylcyclotrisiloxane to remove stains in a short time. It is another object of the present invention to provide a method for cleaning an article that can remove fine foreign matter and oil.

The object of claim 2 is to enable similar cleaning using gaseous hexamethylcyclotrisiloxane.

The object of claim 3 is, in addition to the cleaning method of claim 1 or 2, to reduce the cleaning cost by recovering the cleaning agent.

[0007]

Means for Solving the Problems and Actions In order to achieve the above object, the invention of claim 1 is characterized in that liquid hexamethylcyclotrisiloxane is adhered to the surface of an article and the adhered hexamethylcyclotrisiloxane is solidified at room temperature. After that, air cleaning is a feature. The invention of claim 2 is characterized in that gaseous hexamethylcyclotrisiloxane is adhered to the surface of the article, the adhered hexamethylcyclotrisiloxane is solidified at room temperature, and then air cleaning is performed.
The invention of claim 3 is characterized in that the solidified hexamethylcyclotrisiloxane is recovered and the hexamethylcyclotrisiloxane is regenerated and used.

According to the first aspect of the present invention, when the liquid hexamethylcyclotrisiloxane attached to the surface of the article is solidified, the foreign matter attached to the surface of the article is solidified as a nucleus, and the foreign matter is hexamethyl. It can be incorporated into the crystals of cyclotrisiloxane. The apparent size of the foreign matter at this time becomes significantly large in accordance with the growth of hexamethylcyclotrisiloxane crystals. Therefore, it can be easily blown off from the surface of the article during the subsequent air cleaning. As a result, it is possible to remove the stain without leaving it. Since the freezing point of this hexamethylcyclotrisiloxane is 64.5 ° C., it can be solidified in a shorter time than water and at room temperature. Further, since hexamethylcyclotrisiloxane has solubility in water-insoluble oil, water-insoluble oil stains remaining on the surface of the article can be dissolved and removed.

In the second aspect of the present invention, the hexamethylcyclotrisiloxane vapor is condensed on the surface of the article by introducing the article into the hexamethylcyclotrisiloxane vapor atmosphere, and the hexamethylcyclotrisiloxane is evenly distributed on the surface of the article. Trisiloxane can be attached. It is possible to further increase the probability that foreign substances are taken into the crystals of hexamethylcyclotrisiloxane during the condensation of the vapor. This is because, when the vapor of hexamethylcyclotrisiloxane is condensed, the foreign matter tends to serve as a nucleus, so that the foreign matter is surely taken into the droplet before solidifying. At this time, hexamethylcyclotrisiloxane has a flash point of 23 ° C. and thus may be inflammable. Therefore, cleaning under explosion-proof conditions is preferable.

According to the third aspect of the invention, the hexamethylcyclotrisiloxane removed during the air cleaning does not liquefy at room temperature and can be recovered using this, and the recovered hexamethylcyclotrisiloxane can be recovered. By reusing trisiloxane, it is possible to reduce the running cost of cleaning.

[0011]

[Examples] (Examples 1 to 3) As articles used for cleaning in this example,
A cylindrical sample X made of aluminum having an outer diameter of about 10 mm and a length of about 20 mm was used. Particles of 25 μm or more are attached to the sample X when stored at room temperature and normal humidity.
FIG. 1 shows a cleaning apparatus used in this example, in which 20 pieces of sample X are housed in each cleaning basket 1 of stainless steel mesh having a diameter of 1 mm and a pitch of 8 mm, and each cleaning agent is shown in the treatment steps of Table 1 in sample X. Then, the cleaning agent was solidified by the method shown in the treatment step of Table 1. After the cleaning agent solidified, clean air heated to a temperature equal to or higher than the freezing point of the cleaning liquid, which had been ionized at a pressure of about 4 atm, was supplied from above the cleaning basket 1 as indicated by an arrow A. A hood 2 is arranged below the cleaning basket 1 so that the cleaning agent removed by air is recovered in the recovery tank 3. The collected cleaning agent was circulated through a 0.2 μm filter to remove particles and regenerated.

Residual foreign matter was evaluated on the sample X from which the cleaning agent was removed by supplying clean air, and the cleaning agent recovery rate was obtained. Table 2 shows the cleaning results.

From Table 1, Examples 1 to 3 can solidify the cleaning agent at a high temperature as compared with Comparative Examples 1 to 3 and can simplify the equipment without the need for a cooling device as in the Comparative Example. It turns out that it is advantageous.

From Table 2, Examples 1 to 3 have a significantly shorter cleaning agent solidification time than Comparative Examples 1 to 3, so that the total time of the cleaning process can be shortened and the cleaning power is equivalent. It can be seen that the agent recovery rate is excellent.

Further, using the collected cleaning agent, sample X
When the same washing was carried out by the treatment steps shown in Table 1 using the above, the washing results obtained were the same as those in Table 2.
As a result, the collected cleaning agent can be recycled and used.

[0016]

[Table 1]

[0017]

[Table 2]

Incidentally, "○" in the "Residual foreign matter evaluation" column of Table 2 is 25 μm as a result of observation with a 200 × optical microscope.
It indicates that foreign matter of m or more is not recognized. In addition, the numerical value in the "cleaning agent recovery rate" column of the table is a value calculated by (weight of recovered cleaning agent) / (weight of cleaning agent attached to sample and cleaning basket) x 100.

(Examples 4 to 6) As an article used for cleaning in this example, a cylindrical sample X made of aluminum having an outer diameter of about 10 mm and a length of about 20 mm was used. On this sample X, water-insoluble cutting oil and drill powder when processed, and particles of 25 μm or more when stored at room temperature and normal humidity are attached.

As shown in FIG. 1, this sample X has a diameter of 1 m.
m, 8 mm pitch stainless steel mesh cleaning basket 1
Twenty of each of the cleaning agents were housed in the container, and each cleaning agent was attached to the sample X by the method shown in the processing step of Table 1, and then the cleaning agent was solidified by the method shown in the processing step of Table 1. In the table, Example 1 corresponds to Example 4, Example 2 corresponds to Example 5, Example 3 corresponds to Example 6, Comparative Example 1 is Comparative Example 4, and Comparative Example 2 is Comparative Example 5. Comparative Example 3 corresponds to Comparative Example 6.

After the cleaning agent is solidified, the pressure is about 4 atm.
The clean air, which was ionized and heated to a temperature equal to or higher than the freezing point of the cleaning liquid, was supplied from the upper part of the cleaning basket 1 as shown by an arrow A. A hood 2 is arranged below the cleaning basket 1 so that the cleaning agent removed by air is recovered in the recovery tank 3. 0.2μ of collected cleaning agent
It was circulated using a filter of m to remove dust and particles and regenerated.

For the sample X from which the cleaning agent had been removed by supplying clean air, residual foreign matter evaluation and residual cutting oil evaluation were performed, and the cleaning agent recovery rate was determined. Table 3 shows the cleaning results.

From Table 3, in Examples 4 to 6, not only good cleaning results are obtained even when the water-insoluble cutting oil that cannot be washed with water adheres to the sample. It can be seen that the total time of the cleaning process and the cleaning agent recovery rate are superior to those of No. 6.

Here, the number of cleaning tanks and the cleaning time when the sample is immersed in the cleaning agent are appropriately set depending on the state of the cutting oil. Further, as the cleaning means, suitable means such as ultrasonic cleaning, rocking, jetting, dipping and the like can be used in combination.

When the cutting oil adheres to the sample, the freezing point of the cleaning agent at the time of solidifying the cleaning agent adhering to the sample is lowered, so that the solidification cannot be easily performed. Therefore, removing the cutting oil of the sample by washing beforehand is
It is very effective in easily solidifying the cleaning agent.

Also in this example, when the sample X was subjected to the same cleaning process as shown in Table 1 using the recovered cleaning agent, the same cleaning results as in Table 3 were obtained. Was given. As a result, the recovered cleaning agent can be sufficiently washed even if it is regenerated and used.

[0027]

[Table 3]

The residual foreign matter evaluation and cleaning agent recovery rate in Table 3 are the same as those in Table 2, and "○" in the "Residual cutting oil evaluation" column indicates that no oil content was recognized by the carbon tetrachloride extraction method, "X" indicates that oil was found by the same method.

[0029]

According to the first aspect of the invention, liquid hexamethylcyclotrisiloxane is adhered to the surface of an article to solidify it, and then air cleaning is performed at room temperature to clean fine foreign matters on the surface of the article. It is taken into the crystal of the agent and the detergent is partially melted, and at the same time, it can be easily blown off. Hexamethylcyclotrisiloxane is also soluble in oils and fats, so oils and fats can also be removed,
The cleaning effect can be greatly improved. Furthermore, the freezing point of hexamethylcyclotrisiloxane is 64.5 ° C.
Since it is remarkably higher than the freezing point (0 ° C.) of water, the number of steps for solidifying can be shortened, and it is also advantageous in terms of equipment.

According to the second aspect of the present invention, by introducing the article into the vapor atmosphere of hexamethylcyclotrisiloxane, the detergent can be evenly adhered to the surface of the article, and foreign matters are contained in the crystal of the detergent. It is possible to increase the probability of being taken in and increase the ability to remove foreign matter.

According to the third aspect of the invention, since hexamethylcyclotrisiloxane is less likely to melt than water, it can be easily recovered as a solid and the recovery efficiency is better than that of water.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a cleaning device used in a cleaning method of the present invention.

Claims (3)

[Claims] 1. A method for cleaning an article, which comprises depositing liquid hexamethylcyclotrisiloxane on the surface of the article, solidifying the attached hexamethylcyclotrisiloxane at room temperature, and then performing air cleaning. 2. A method for cleaning an article, comprising depositing gaseous hexamethylcyclotrisiloxane on the surface of the article, coagulating the attached hexamethylcyclotrisiloxane at room temperature, and then performing air cleaning. 3. The hexamethylcyclotrisiloxane which is solidified is recovered and the hexamethylcyclotrisiloxane is regenerated and used.
The described cleaning method.