JP3569980B2 - Draining drying method - Google Patents

Description

【００４５】
【表２】

【００４６】
【発明の効果】
本発明方法は、オゾン層破壊などの環境問題を生じるおそれは少ない。さらに、物品の表面に付着した水を効率的に除去し、物品を完全に乾燥することができる。温風、赤外線ヒーター、減圧加熱等の従来の乾燥方法と較べ、時間を大幅に短縮でき、乾燥にかかる電気コストを削減することで安価に水切り乾燥を行うことができる。
【図面の簡単な説明】
【図１】本発明の水切り乾燥方法に用いる装置の一例を示す図。
【符号の説明】
１：水切り乾燥装置
２：浸漬水切り槽
３：蒸気槽
４：蒸気ゾーン
５：冷却管
６：凝縮溶剤水分離器
７：加温槽
８：水分離槽
９：循環ポンプ
１０：ヒーター
１１：超音波発振器
１２：ヒーター
１３：水
１４：混合溶剤[0001]
[Industrial applications]
The present invention relates to a draining and drying method for removing water from the surface of an article such as a lens, a liquid crystal display device component, an electronic component, and a precision machine component in the precision machine industry, the optical machine industry, the electric / electronic industry, the plastic industry, and the like.
[0002]
[Prior art]
In many cases, the above-mentioned article does not become a product if water remains attached after the washing process. Therefore, water is usually removed using an organic solvent. As an organic solvent, 1,1,2-trichloro-1,2,2-trifluoroethane (hereinafter, referred to as R113) or 1,1,1-trichloroethane (hereinafter, referred to as R140a) is widely used as a draining and drying solvent. .
[0003]
[Problems to be solved by the invention]
R113 and R140, which have been used conventionally, have various advantages, but because they are extremely stable chemically, they have a long life in the troposphere and diffuse to reach the stratosphere, where they are decomposed by ultraviolet rays to convert chlorine radicals. It is said that this chlorine radical causes a chain reaction with stratospheric ozone and destroys the ozone layer. Therefore, its use has been restricted, and R113 and R140a are to be totally abolished in 1996.
[0004]
Further, these R113 and R140a are widely used as cleaning agents. Instead of these, some methods of washing with an alkaline detergent, a detergent containing a surfactant and a hydrocarbon, or water are used. However, even when these cleaning agents are used, a rinse for washing the cleaning agent with water after the cleaning is required. Therefore, it is necessary to remove and dry water, including when washing with water.
[0005]
As a general drying method, there is a method by heating, air blowing, reduced pressure or a combination thereof, but it takes a long time to completely dry an article into small gaps. Because of the long drying time, it is also difficult to obtain high cleanliness on the surface of the article to be cleaned after drying.
[0006]
Thus, not only in the case where R113 or R140a is conventionally used as a draining and drying solvent, but also in the case where washing or rinsing with water is newly performed, efficient and safe draining and drying in place of R113 or R140a is performed. Was needed. An object of the present invention is to provide a novel draining and drying method that solves these problems.
[0007]
[Means for Solving the Problems]
The present invention is a lower Symbol methods.
[0008 ]
[0009]
On the front surface of the article water is attached, and an alcohol, 1,1-dichloro-2,2,3,3,3-pentafluoropropane and 1,3-dichloro-1,1,2,2,3 A mixed solvent with at least one halogenated hydrocarbon selected from pentafluoropropane, wherein the mixed solvent having a liquid temperature of 40 ° C. or higher is immersed in a immersion drainage tank and pulled up; Alternatively, a draining / drying method characterized in that water adhering to the article is removed by holding in an atmosphere of halogenated hydrocarbons and performing steam cleaning .
[0010]
The alcohol in the present invention is not particularly limited as long as it can separate water from the article surface in a short time and efficiently separate a mixture of water and the halogenated hydrocarbon when used in combination with the halogenated hydrocarbon. Not done. Because of such excellent separation performance, at least one selected from methanol, ethanol, n-propanol and isopropanol is preferable.
[0011]
Halogenated hydrocarbons of the present invention is preferred in terms of safety since no pull fire point. Selected from compounds below.
[0012 ]
[0013]
1,1-dichloro-2,2,3,3,3-pentafluoropropane (hereinafter abbreviated as R225ca), 1,3-dichloro-1,1,2,2,3-pentafluoropropane (hereinafter R225cb) Abbreviated ).
[0014]
[0015 ]
[0016]
Among them, at least one of R225ca and R225cb, which has low destruction ability and toxicity of the ozone layer, is easy to handle in a boiling point range of 50 to 60 ° C., is easily industrially available, is easily available, and the like. One is particularly preferred.
[0017]
The mixed solvent of an alcohol and a halogenated hydrocarbon in the present invention (hereinafter, simply referred to as a mixed solvent) preferably has a composition having no flash point. The mixing ratio of alcohols and halogenated hydrocarbons is such that alcohols / halogenated hydrocarbons = 1-20 / 80-99% (weight%, the same applies hereinafter), preferably alcohols / halogenated hydrocarbons = 1. -10 / 90-99%.
[0018]
Further, in order to easily carry out steam cleaning, the mixed solvent is preferably an azeotropic composition or an azeotropic composition showing the same behavior as the azeotropic composition in practical use. Specifically, the following azeotropic compositions or azeotropic-like compositions are particularly preferred.
[0019]
R225ca / ethanol = 97.3 / 2.7%, R225ca / methanol = 94.7 / 5.3%, R225cb / ethanol = 95.6 / 4.4%, R225cb / methanol = 93.3 / 6.7. %, R225ca / R225cb / ethanol = 94.8 / 2.7 / 2.5% or R225ca / R225cb / methanol = 89.8 / 5.6 / 4.6%.
[0020]
R225ca / ethanol = 95-98 / 2-5%, R225ca / methanol = 93-96 / 4-7%, R225cb / ethanol = 94-97 / 3-6% or R225cb / methanol = 92-97 / 3-8. % Azeotropic composition.
[0021]
Conventional R113 and R140a are widely used as cleaning agents. Instead of these, some methods of washing with an alkaline detergent, a detergent containing a surfactant and a hydrocarbon, or water are used. However, even when these cleaning agents are used, a rinse for washing the cleaning agent with water after the cleaning is required. Therefore, it is necessary to remove and dry water, including when washing with water.
[0022]
According to the method of the present invention, an article having water adhered to its surface is immersed in a mixed solvent maintained at a temperature of 40 ° C. or higher. Examples of the articles having water adhered to the surface include, but are not limited to, articles which have been adhered to water by washing with water or by washing with a detergent other than water and rinsing the detergent with water. An article to which moisture in the air adheres may be used.
[0023]
The temperature of the mixed solvent in the immersion drainage tank is 40 ° C. or higher, preferably 45 ° C. or higher, and particularly preferably 50 ° C. or higher. The upper limit of the temperature of the mixed solvent is the azeotropic temperature when the mixed solvent is an azeotropic composition, and the lowest of the boiling points of the solvents in the mixed solvent when the mixed solvent is not an azeotropic composition. Is preferred.
[0024]
In removing water adhering to the surface of the article from the surface of the article in the immersion draining tank, the time for draining can be reduced by performing ultrasonic cleaning, swing cleaning, jet cleaning, or a combination of these. If the temperature of the mixed solvent is less than 40 ° C. during the immersion draining, the water removed from the article surface is easily dispersed in the mixed solvent. Dispersion of water causes serious problems such as difficulty in separating water for circulating the mixed solvent and incomplete drying and generation of spots due to adhesion of the dispersed water to articles.
[0025]
Next, the water-removed article is held in a mixed solvent or a vapor of a halogenated hydrocarbon. The vapor of the mixed solvent or the halogenated hydrocarbon condenses on the surface of the article and drains until the surface of the article reaches the boiling point of the mixed solvent or the halogenated hydrocarbon, and simultaneously raises the temperature of the surface of the article. Rinsing for cleaning dirt on the article surface may be performed simultaneously with draining.
[0026]
Finally, the article is withdrawn from the mixed solvent or vapor of the halogenated hydrocarbons. The water adhering to the article surface is completely removed, and the article surface temperature has reached the boiling point of the mixed solvent, the mixed solvent is not taken out, and the article is sufficiently dried.
In the method of the present invention, after heating a mixed solvent containing water separated from an article by immersion drainage to 40 ° C. or higher, the water and the mixed solvent are layer-separated by a specific gravity difference, and a part of the mixed solvent is used. Alternatively, the whole may be circulated to the immersion drainage tank.
[0027]
Further, according to the present invention, the mixed solvent containing water separated from the article surface by immersion drainage is heated more than the state used for immersion drainage, and then water and the mixed solvent are layer-separated by a difference in specific gravity to separate water. Only the mixed solvent not containing can be circulated to the immersion draining tank. By heating before this layer separation, effective separation can be performed in a short time. The heating temperature is more effective as the temperature difference from the immersion drainage tank is larger, and there is no problem even if the temperature is raised to the boiling point of the mixed solvent.
[0028]
Before immersing the article in the immersion draining tank, the article is subjected to at least one operation selected from the group consisting of air blowing, hot air blowing, centrifugation, and vibration to reduce the amount of water adhering to the article surface, The amount of water brought into the immersion drainage tank can also be reduced. The reduction in the amount of adhered water can reduce the amount of alcohols distributed to the water layer during water separation and discarded together with the water, and can be more economically drained and dried.
[0029]
The drawings are shown below to further clarify the features of the present invention. In FIG. 1, which shows an example of an apparatus that can be employed in the draining / drying method of the present invention, an article is immersed in a mixed solvent placed in an immersion draining tank 2 in a draining / drying apparatus 1, and water adhering to the surface of the article is immersed therein. Is removed. The mixed solvent in the immersion drainage tank 2 is heated to 40 ° C. or higher by the heater 10 in order to improve drainage and prevent dispersion of water. In order to drain the water in a short time, ultrasonic cleaning can be performed by the ultrasonic oscillator 11.
[0030]
Next, the drained article is pulled up from the immersion draining tank 2 and steam-washed in the steam tank 3. In this steam cleaning, the mixed solvent condenses on the surface of the article until the surface temperature of the article reaches the boiling point of the mixed solvent, and the article is further rinsed by the condensed mixed solvent. Further, after the temperature of the article reaches the boiling point of the mixed solvent, the article is taken out of the steam tank 3 so that the liquid mixed solvent is not taken out. Therefore, the surface of the article is completely dried after being taken out of the steam tank 3.
[0031]
In the circulation path of the mixed solvent in FIG. 1, first, the mixed solvent turns into steam in the steam tank 3 to form a steam zone 4. This vapor condenses in the cooling pipe 5 and enters the condensed solvent water separator 6. In the condensed solvent water separator 6, water in the air mainly condensed together with the mixed solvent in the cooling pipe 5 is separated into layers.
[0032]
The mixed solvent from which water has been separated and removed is then sent to the immersion draining tank 2. In the immersion draining tank 2, water adhering to the article is mixed, and the mixed solvent and water are mixed. Next, the mixed solvent containing water is sent to the heating tank 7.
[0033]
In the heating tank 7, the heater 12 heats the temperature to a higher temperature than in the immersion draining tank. The mixed solvent containing water further heated by this is then sent to the water separation tank 8, where the upper layer is separated into two layers of water 13 and the lower layer is mixed solvent 14.
[0034]
Part of the layered mixed solvent is sent to the steam tank 3, and the rest is sent to the immersion draining tank 2 by the circulation pump 9. In the immersion draining tank 2, when the article is immersed, the water removed from the article floats. The mixed solvent sent to the immersion draining tank 2 by the circulating pump is used to send the floating water to the heating tank 7. A mixed solvent outlet from the circulation pump 9 can be devised so that a layered flow is created on the liquid surface and the floating water can be sent out efficiently.
[0035]
FIG. 1 shows an example in which the method of the present invention is used. The heating tank 7 and the water separation tank 8 may be independent devices or may be all the same device. In addition, individual immersion draining methods, steam cleaning methods, and water separation methods by layer separation are not particularly limited, and other general methods can be employed.
[0036]
【Example】
[Example 1]
A stainless steel mesh (5 cm × 5 cm), which had been well washed in advance, was immersed in water and used as an article to perform a drainage drying test. The compounds shown in Table 1 were used as the halogenated hydrocarbon. In addition, R225ca / cb means a mixture of R225ca / R225cb = 50/50%. Ethanol was used as the alcohol, and the content was 5% in the mixed solvent.
[0037]
First, the article was immersed in a mixed solvent at 45 ° C., and drained for 1 minute using ultrasonic waves. Next, steam cleaning was performed in the halogenated hydrocarbon steam zone for 30 seconds. Table 1 shows the results of observing the drying properties after steam washing, the state of the mixed solvent after immersion and drainage, and the state of water floating on the liquid surface of the mixed solvent when immersion and drainage.
[0038]
In the table, the drying properties are represented by ◎: complete drying without stains, ；: dry but slightly stained, Δ: slight water remaining, x: much water remaining. The state of the mixed solvent was represented by ◎: no turbidity, ；: slight turbidity was felt, Δ: slightly turbid, ×: strongly turbid. The state of water floating on the liquid surface was represented by ◎: quickly floating, ；: slightly floating, Δ: slowly floating, ×: extremely slow floating of water.
[0039]
[Comparative Example 1]
A drainage drying test was performed using R113 containing 5% of ethanol instead of the mixed solvent of Example 1. First, the article was immersed in R113 at 45 ° C., and drained for 1 minute using ultrasonic waves. Next, steam cleaning was performed for 30 seconds in the steam zone of R113. Table 1 shows the results of evaluation performed in the same manner as in Example 1.
[0040]
According to Table 1, the examples in the method of the present invention showed good drainage drying properties as compared with the conventionally used drainage drying of R113.
[0041]
[Example 2]
A stainless steel mesh (5 cm × 5 cm), which had been well washed in advance, was immersed in water and used as an article to perform a drainage drying test. The compounds shown in Table 2 were used as the halogenated hydrocarbon. Ethanol was used as the alcohol, and the content of each mixed solvent was adjusted to 5%.
[0042]
First, the article was immersed in a mixed solvent of 30 ° C., 35 ° C., 40 ° C., and 45 ° C., and drained for 1 minute using ultrasonic waves. Next, steam cleaning was performed in the halogenated hydrocarbon steam zone for 30 seconds. The results of the evaluation based on the same criteria as in Example 1 were obtained by observing the drying properties after steam washing, the state of the mixed solvent after immersion and drainage, and the state of water floating on the liquid surface of the mixed solvent during immersion and drainage. It is shown in FIG.
[0043]
According to Table 2, by setting the temperature of the mixed solvent at the time of immersion drainage to 40 ° C. or higher, stable and excellent drainage drying can be performed.
[0044]
[Table 1]

[0045]
[ Table 2 ]

[0046]
【The invention's effect】
The method of the present invention is less likely to cause environmental problems such as ozone layer depletion. Further, water adhering to the surface of the article can be efficiently removed, and the article can be completely dried. Compared with conventional drying methods such as hot air, infrared heaters, and reduced pressure heating, the time can be greatly reduced, and the drying cost can be reduced by reducing the electricity cost required for drying.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an apparatus used for a draining and drying method of the present invention.
[Explanation of symbols]
1: Draining / drying device 2: Immersion draining tank 3: Steam tank 4: Steam zone 5: Cooling pipe 6: Condensed solvent water separator 7: Heating tank 8: Water separation tank 9: Circulation pump 10: Heater 11: Ultrasonic Oscillator 12: Heater 13: Water 14: Mixed solvent

Claims (2)

An article having water adhered to its surface is treated with alcohols, 1,1-dichloro-2,2,3,3,3-pentafluoropropane and 1,3-dichloro-1,1,2,2,3-pentane. A mixed solvent with at least one halogenated hydrocarbon selected from fluoropropane , the temperature of which is 40 ° C. or higher; a mixed solvent containing the mixed solvent; A draining / drying method comprising removing water adhering to an article by carrying out steam cleaning while holding the vapor in halogenated hydrocarbons. The method according to claim 1, wherein the mixed solvent is an azeotropic or azeotropic-like mixed solvent.

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