JP5217697B2 - How to drain water - Google Patents

Description

  The present invention relates to a draining method for articles such as electronic parts, optical parts, precision machine parts and the like.

  Conventionally, as a method of removing moisture adhering to an article after washing with a water-soluble cleaning agent, the article is brought into contact with alcohol and then brought into contact with a fluorinated solvent having higher drying property than alcohol. A method of removing moisture and drying is widely known.

In the above method, the fluorinated solvent after contacting the article with the fluorinated solvent comprises an alcohol. If the fluorinated solvent is continuously used without removing the alcohol, the article gradually becomes difficult to dry, and there is a risk of poor cleaning such as a spot on the article.
For this reason, the method of removing alcohol by making water contact the fluorinated solvent containing alcohol and reusing a fluorinated solvent is performed. (See Patent Document 1 and Patent Document 2.)
JP 2007-27239 A (prior art) JP-A-6-210103 (background art)

  However, in such a conventional method, since there is no index for removing alcohol, the alcohol removal rate varies depending on the amount of water contact, and stable draining and drying may not be possible. Specifically, when the amount of water contact is small, the alcohol removal rate is low, so the drying property of the article is deteriorated, resulting in poor cleaning. On the other hand, when the amount of water contact is large, the alcohol removal rate is high. However, from the viewpoint of global warming, the amount of fluorinated solvent that is desired to be reduced as much as possible is increased in the wastewater and discharged, and it is necessary to replenish the discharged fluorinated solvent more. Arise.

  An object of the present invention is to provide a method for draining an article, which can sufficiently remove alcohol from a fluorinated ether which is a kind of a fluorinated solvent and can reduce the fluorinated ether discharged as waste water.

The present invention provides an alcohol contact step of contacting an article with alcohol,
An ether substitution step in which the article is brought into contact with the fluorine-containing ether represented by Formula 1;
An extraction step of taking out the fluorinated ether containing alcohol from the ether substitution step,
A water extraction step in which 0.2 to 2 times the amount of water is brought into contact with the fluorine-containing ether containing the alcohol extracted in the extraction step with respect to the mass of the fluorine-containing ether;
A water separation step for separating fluorine-containing ether and alcohol-containing water;
Provided is a method for draining an article comprising a step of returning fluorine-containing ether separated from water to the ether substitution step.

R ^f —O—R Formula 1
In Formula 1, R ^f is a perfluoroalkyl group having 3 to 6 carbon atoms, R is an alkyl group having 1 to 3 carbon atoms, and the total number of carbon atoms contained in R ^f and R is 4-9.

According to the present invention, a predetermined amount of water is brought into contact with the fluorinated ether represented by the formula 1 containing alcohol, thereby sufficiently removing the alcohol from the fluorinated ether and reducing the discharge amount of the fluorinated ether. Can be reduced.
A fluorine-containing solvent containing a fluorine-containing ether is a compound that is desired to reduce the released amount as much as possible from the viewpoint of global warming. Since wastewater containing this must be treated appropriately, it is very advantageous to be able to reduce this discharge.

<Fluorine-containing ether>
The fluorine-containing ether in the present invention is a compound represented by Formula 1. R ^f is a perfluoroalkyl group having 3 to 6 carbon atoms, R is an alkyl group having 1 to 3 carbon atoms, and the total number of carbon atoms contained in R ^f and R is 4 to 9 is there.
R ^f —O—R Formula 1
R ^f may be linear or branched.

Since the article having alcohol on the surface is brought into contact with the fluorinated ether and the surface of the article is replaced with the fluorinated ether and dried, it is preferable to use a fluorinated ether having a boiling point of 30 to 100 ° C., From this viewpoint, a fluorine-containing ether in which the total number of carbon atoms contained in R ^f and R is 5 is more preferable.
A fluorine-containing ether may be used by 1 type, and 2 or more types may be mixed and used for it.

Specific examples of the fluorine-containing ether represented by Formula 1 include the following compounds.
1-methoxy-1,1,2,2,3,3,3-heptafluoropropane, 1-ethoxy-1,1,2,2,3,3,3-heptafluoropropane, 1-methoxy-2- Trifluoromethyl-1,1,2,3,3,3-hexafluoropropane, 1-methoxy-1,1,2,2,3,3,4,4,4-nonafluorobutane, 1-ethoxy- 2-trifluoromethyl-1,1,2,2,3,3,3-hexafluoropropane, 1-ethoxy-1,1,2,2,3,3,4,4,4-nonafluorobutane, 1-Methoxy-1-pentafluoroethyl-2-trifluoromethyl-1,2,3,3,3-pentafluoropropane Among them, an object to be cleaned substituted with a fluorine-containing ether is easily dried and taken out. Boiling point that can be easily handled later 1-methoxy-2-trifluoromethyl-1,1,2,3,3,3-hexafluoropropane, 1-methoxy-1,1,2,2 , 3,3,4,4,4-nonafluorobutane, 1-ethoxy-2-trifluoromethyl-1,1,2,2,3,3,3-hexafluoropropane, 1-ethoxy-1,1 2,2,3,3,4,4,4-nonafluorobutane is preferred.

  Moreover, since the above-mentioned fluorine-containing ether may be used not only as a single component but also as a mixture of two or more types, as a mixture of two or more types, 1-methoxy-3-trifluoromethyl-1,1, A mixture of 2,3,3,3-hexafluoropropane and 1-methoxy-1,1,2,2,3,3,4,4,4-nonafluorobutane (boiling point 61 ° C.), 1-ethoxy-3 A mixture of trifluoromethyl-1,1,2,3,3,3-hexafluoropropane and 1-ethoxy-1,1,2,2,3,3,4,4,4-nonafluorobutane (boiling point) 76 ° C.) is preferred.

<Alcohol>
The alcohol used in the present invention is easily available and preferably soluble in the fluorinated ether represented by Formula 1. Methanol and ethanol having a boiling point of 60 to 90 ° C. from the viewpoint of high solubility in water and, as a result, easy extraction from the fluorinated ether containing the alcohol and easy reuse of the fluorinated ether. 2-propanol.

<Article>
The present invention, for example, removes water adhering to a part after washing the cutting oil / working oil and cutting / polishing waste adhering to the part subjected to cutting / polishing with a water-soluble detergent such as a detergent. Parts that have been subjected to the drying process, the optical parts such as the lens after processing and before the surface treatment are removed by washing with water-soluble cleaning agents such as detergents and then dried, and the parts that have been plated It can be applied to a process of removing the water adhering to the part after washing the plating solution adhering to the substrate and drying it.

  That is, as an article to which the draining method of the present invention can be applied, electronic parts such as printed circuit boards, hoop agents, liquid crystal displays, magnetic recording parts, semiconductor materials, piezoelectric element materials, magnetic recording parts, photoelectric conversion parts, and motor parts Machine parts such as ticket issuing parts, money inspection parts, precision machine parts such as bearings and watches, optical parts such as optical lenses, prisms, crystals, polygon mirrors and optical filters, and precision machines for processing such as carbide chips. There are various articles such as parts.

The materials of the base materials constituting these articles include metals such as iron, stainless steel, magnesium, aluminum, zinc, silver, copper, copper alloys, tin, alumite sulfate, and copper, zinc, nickel, chromium, and gold. Plastic materials such as plated metal, vinyl chloride resin, polyethylene resin, polypropylene, polystyrene, polycarbonate, polyacetal, polyphenylene oxide, phenol resin, ABS resin, nylon 6, nylon 66, PTFE resin, PCTFE resin, epoxy resin , Polyphenylene sulfide, polybutylene terephthalate, polycondensate of ethylene terephthalate and parahydroxybenzoic acid, polycondensate of phenol and phthalic acid and parahydroxybenzoic acid, 2,6-hydroxynaphthoic acid and parahydride Polymeric materials polycondensate with carboxy acid, and glass.
The fluorine-containing ether in the present invention is preferable from the viewpoint of not affecting these substrates.

<Alcohol contact process>
For example, the alcohol contact process removes water adhering to the parts after washing the cutting oil / working oil and cutting / polishing waste adhering to the parts subjected to cutting / polishing with a water-soluble detergent such as detergent. And drying, removing the water adhering to the lens after washing the lens and other optical parts with a water-soluble detergent such as detergent, and the plating solution adhering to the plated parts. In the process of removing the water adhering to the parts after washing and drying, the water adhering to the article to be cleaned is removed by dissolving it in alcohol. As a method of bringing the alcohol into contact with the article, any of a method of spraying alcohol with a spray method, a method of contacting with alcohol vapor, a method of immersing in an alcohol liquid, or a combination of these methods may be used. Good.

<Ether substitution step>
In the ether substitution step, the method of bringing the article into contact with the fluorinated ether includes immersing the article in a fluorinated ether liquid, spraying the article with the fluorinated ether in a spray manner, and contacting the article with the vapor of the fluorinated ether. And the like.

  Further, in order to increase the efficiency of replacing the alcohol adhering to the article with the fluorinated ether, the same contact method may be repeated or different contact methods may be combined. In particular, when the method of immersing or spraying the article in the fluorinated ether and the method of bringing the article into contact with steam are combined, the effect of replacing the alcohol adhering to the article with the fluorinated ether is enhanced. In this case, it is preferable that the article is immersed in the fluorine-containing ether or sprayed, and then rinsed by exposure to steam.

  In addition, in the method of immersing the article in the fluorinated ether, a method of irradiating ultrasonic waves during immersion, a method of moving the article up and down in the immersion liquid, a method of rotating the article in the immersion liquid, or an article from the immersion liquid By adopting a method of taking in and out the vapor area above the liquid, the effect of replacing alcohol with fluorine-containing ether can be improved.

  The concentration of alcohol contained in the fluorinated ether that hangs down from the article in this step depends on the shape of the article. When the shape of the article is smooth and has no unevenness, the alcohol concentration of the condensate is 0.01% to 10% by weight. However, when the shape of the article is complex and rich in unevenness, the alcohol concentration of the condensate is as high as 30% by weight. Become. In addition, the concentration of alcohol contained in the fluorine-containing ether that hangs down from the article is more greatly affected by the shape of the instrument on which the article is mounted, and has a complicated shape with fine mesh and small gaps. In such a case, the alcohol concentration of the condensate may be as high as 50% by mass.

<Removal process>
In the extraction step, the fluorinated ether containing alcohol adhering to the surface of the article is sent to the water extraction step.

  As a specific method, as described in the background art (Patent Document 2), the article is brought into contact with fluorine-containing ether vapor, the fluorine-containing ether condensed on the surface is collected in a tray, and the fluorine-containing ether sprayed on the article There are a method of collecting the liquid in a receiving pan, a method of collecting the liquid in a tank in which the article is immersed, a method of collecting a liquid in a tank (hereinafter referred to as a steam tank) that generates a vapor of fluorine-containing ether.

<Water extraction process>
In the water extraction step, the fluorine-containing ether containing alcohol is added to the fluorine-containing ether in a mass of 0. Contact with water more than 4 times, and extract alcohol with water.
0. When four times or more of water is added, the alcohol in the fluorinated ether can be sufficiently removed. Therefore, even when the fluorinated ether ether from which the alcohol has been removed is returned to the substitution step and operated, the surface of the article is removed. The water draining and drying can be operated stably without causing any defects such as water .

On the other hand, when the amount of water to be contacted is too large, a large amount of fluorine-containing ether may be taken into water and discharged as waste water. And less than 1 times.

  Examples of the method for bringing the fluorine-containing ether into contact with water include the following methods. Utilizing the difference in specific gravity between water and fluorine-containing ether, water is supplied from the bottom of the contact tank, fluorine-containing ether is supplied from the top, and both are continuously contacted. And a layer comprising a fluorine-containing ether, and a method of pumping the fluorine-containing ether layer with a pump and flowing it from above a contact tank containing water.

  It is preferable that the fluorine-containing ether containing alcohol is brought into contact with water in the form of droplets as fine as possible. In order to make fine droplets, when water is supplied from the lower part of the contact tank and fluorine-containing ether is supplied from the upper part, the parts to be flowed out may be made into a mesh or pores, respectively. When mixing an aqueous layer and a layer made of fluorine-containing ether in a batch, a method of stirring using a stirrer or a method of sealing a contact tank and shaking using a shaker or the like can be applied.

<Water separation step, step for returning to the ether substitution step>
After the water extraction step, the fluorine-containing ether layer and the aqueous layer are separated into two upper and lower layers by, for example, standing still. Since the lower layer separated into two layers is a fluorine-containing ether, the lower layer separated in this step is returned to the ether substitution step. Moreover, since the upper layer is an aqueous layer containing alcohol, it is treated as waste water.

  Hereinafter, examples and comparative examples of the present invention will be described with reference to FIG. Examples 4 to 9 and 12 are examples, and examples 1 to 3 and 10 to 11 are comparative examples.

<Article>
A SUS304 stainless steel plate (length 100 mm × width 100 mm × thickness 2 mm) that had been thoroughly cleaned in advance was prepared.

(Cleaning test 1) Examples 1 to 11
The article was immersed in a cutting oil (Daphnicut AS-40H: manufactured by Idemitsu Kosan Co., Ltd.) for 10 seconds, pulled up, and left for 5 minutes. Then, it was immersed for 1 minute in 2L detergent (Power Cleaner: manufactured by Kao Corporation) filled in a 3L beaker, and then immersed for 1 minute in 2L detergent (Power Cleaner) filled in another 3L beaker (aqueous cleaning) Step 1). Then, it was immersed in 2 L of tap water filled in a 3 L beaker for 1 minute, and further immersed in 2 L of tap water filled in another 3 L beaker for 1 minute. Subsequently, it was immersed in 2 L of distilled water filled in a 3 L beaker for 1 minute, and further immersed in 2 L of distilled water filled in another 3 L beaker (rinsing step 2).

  Then, it was immersed in 2 L of ethanol filled in a 3 L beaker and held for 1 minute. Further, it was immersed in 2 L of ethanol filled in another 3 L beaker and held for 1 minute. All were performed in the state which irradiated the ultrasonic wave of 40kHz at 40 degreeC (alcohol contact process 3).

The article is taken out from ethanol, and then HFE-7100 (product name of Sumitomo 3M, CF ₃ CF ₂ CF ₂ CF ₂ —O—CH ₃ and CF ₃ CF (CF ₃ ) CF ₂ —O—CH, which is a fluorine-containing ether. ₃ ), boiling point 61 ° C.) for 3 minutes, the article was taken out, and ethanol was replaced with fluorine-containing ether. As a steam generator, a 3 L glass beaker equipped with a cooling coil was used, 200 ml of fluorine-containing ether was added, and this was heated to 61 ° C. to generate steam (ether replacement step 4).

  In the ether substitution step 4 in which the article is brought into contact with the fluorinated ether, the fluorinated ether that condenses and hangs down on the surface of the article is sampled and collected by providing a container at the bottom of the article. In the ether substitution step, the mass of the fluorinated ether condensed on the surface of the article was 10 g, and the ethanol concentration of the condensate was 5 mass%.

  The taken-out fluorine-containing ether is put into a 100 ml glass container, water is added at a rate shown in Table 1, and sealed, and shaken and mixed at 25 ° C. for 5 minutes at a speed of 1 reciprocation per second with a shaker. Contacted (water extraction step 6).

  After contacting the fluorine-containing ether with water, the mixture is left to stand to separate the fluorine-containing ether and water into two layers to separate the fluorine-containing ether and water (water separation step 7), and the fluorine-containing ether is converted to the fluorine-containing ether. Returned to steam generator.

  After the processing oil is attached to the article, it is washed with an aqueous cleaning agent, brought into contact with alcohol, then brought into contact with a fluorinated ether, and the collected condensate is brought into contact with water and returned to the washing tank. The above operation was continuously repeated for 5 days at 30 times / day. In addition, each liquid of the water-system washing | cleaning process 1, the rinsing process 2, and the alcohol contact process 3 was replaced | exchanged for the new liquid once a day.

(Cleaning test 2) Example 12
A washing test was conducted in the same manner as in Example 7 except that 2-propanol was used as the alcohol instead of ethanol.

<Evaluation method>
(1) Ethanol removal rate After completion of the test, the ethanol content in the fluorine-containing ether after the water extraction step and the ethanol content in the condensate generated in the ether substitution step were measured using an Agilent gas chromatograph (Agilent 6890GC). System) and the percentage of ethanol removed was calculated.

(2) Evaluation of detergency and dryness The dry state of the stainless steel plate surface at the end of the operation after 5 days was visually confirmed.

(3) Loss rate of fluorinated ether Further, the concentration of the fluorinated ether contained in the aqueous layer after the water extraction step was measured by a gas chromatograph (Agilent 6890GC system) manufactured by Agilent. The ratio of the amount of the fluorinated ether contained in the aqueous layer to the charged amount of the initial fluorinated ether was calculated as the loss rate of the fluorinated ether.

<Evaluation results>
The evaluation results of Examples 1 to 11 are shown in 1.
The ethanol removal rate was expressed as ◯: 90% or more, Δ: ethanol removal rate 80% to 90%, and x: ethanol removal rate less than 80%.
In addition, the detergency and dryness were expressed as ◯: the solvent was quickly evaporated, Δ: the solvent was slowly evaporated, and X: the spot was not evaporated.
The loss rate of fluorine-containing ether is as follows: ○: fluorine-containing ether loss rate of less than 0.02%, Δ: fluorine-containing ether loss rate of 0.02 to 0.05%, ×: fluorine-containing ether loss rate of 0.05% or more, Expressed as:

The evaluation results of Example 12 are shown in Table 2.
In Table 2, the 2-propanol removal rate is ◯: 90% or more, Δ: 2-propanol removal rate 80% to 90%, and x: 2-propanol removal rate less than 80%. The meanings of ○, ×, and Δ relating to the detergency, drying property, and loss rate of the fluorine-containing ether are the same as in Table 1.

  The present invention can be applied to cleaning and drying of articles such as electronic parts, optical parts, and cutting parts.

The flowchart of the draining method of this invention.

Explanation of symbols

A: Flow for washing and drying B: Flow for removing alcohol in fluorine-containing ether 1: Water-based washing step 2: Rinsing step 3: Alcohol contact step 4: Ether substitution step for contacting with fluorine-containing ether 5: Fluorine-containing ether removal step 6: Water extraction process 7: Water separation process 8: Separated water

Claims (6)

An alcohol contact process in which an article with water or an aqueous solution attached is brought into contact with alcohol;
An ether substitution step in which the article is brought into contact with the fluorine-containing ether represented by the formula 1,
An extraction step of taking out the fluorinated ether containing alcohol from the ether substitution step,
With respect to the mass of the fluorinated ether, the fluorinated ether containing the alcohol extracted from the extraction step has a ratio of 0. A water extraction step for contacting 4 to 1 times the amount of water;
A water separation step for separating fluorine-containing ether and alcohol-containing water;
A method for draining an article, comprising a step of returning the fluorine-containing ether separated from water to the ether substitution step.
R ^f —O—R Formula 1
In Formula 1, R ^f is a perfluoroalkyl group having 3 to 6 carbon atoms, R is an alkyl group having 1 to 3 carbon atoms, and the total number of carbon atoms contained in R ^f and R is 4-9.   The fluorine-containing ether is 1-methoxy-2-trifluoromethyl-1,1,2,3,3,3-hexafluoropropane and 1-methoxy-1,1,2,2,3,3,4,4. The draining method according to claim 1, wherein the draining method is at least one selected from 1,4-nonafluorobutane.   The draining method according to claim 1 or 2, wherein the alcohol is methanol, ethanol or 2-propanol.   The draining method according to claim 1, 2 or 3, wherein the article is brought into contact with the vapor of the fluorinated ether in the ether substitution step.   5. The draining method according to claim 4, wherein, in the ether substitution step, the article is immersed in a fluorine-containing ether liquid and then brought into contact with the fluorine-containing ether vapor.   The draining method according to any one of claims 1 to 5, wherein in the water extraction step, water is supplied from the lower part of the contact tank, fluorine-containing ether is supplied from the upper part of the contact tank, and both are continuously brought into contact with each other.

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