WO2021048757A1

WO2021048757A1 - Regeneration method for alcohol-containing fluorinated liquid and regeneration system using the method

Info

Publication number: WO2021048757A1
Application number: PCT/IB2020/058377
Authority: WO
Inventors: Yusuke Saito
Original assignee: 3M Innovative Properties Company
Priority date: 2019-09-10
Filing date: 2020-09-09
Publication date: 2021-03-18
Also published as: JP2021041337A

Abstract

A regeneration method for an alcohol-containing fluorinated liquid according to one embodiment of the present disclosure includes: step A of supplying, from an effluent tank or an effluent line, effluent containing an alcohol-containing fluorinated liquid mixed with water into a first mixing tank and bringing the effluent into contact with water to prepare a first mixed liquid; step B of filtering the first mixed liquid with a first oil-water separator to separate the first mixed liquid into a first upper layer liquid and a first lower layer liquid; step C of supplying the first upper layer liquid to a waste liquid tank directly or via the first mixing tank and allowing it to stand and separating the first upper layer liquid into a second upper layer liquid and a second lower layer liquid; step D of supplying the second lower layer liquid from the waste liquid tank to the effluent tank or the effluent line; step E of discharging the second upper layer liquid from the waste liquid tank; and step F of adding an alcohol to the fluorinated liquid obtained from the first lower layer liquid.

Description

REGENERATION METHOD FOR ALCOHOL-CONTAINING FLUORINATED LIQUID AND REGENERATION SYSTEM USING THE METHOD

Technical Field

The present disclosure relates to a regeneration method for an alcohol-containing fluorinated liquid, and a regeneration system using the regeneration method.

Background

For example, a method for making an organic EL display includes a step of evaporating RGB three colors of dye on a substrate such as glass via a metal mask to form an organic light-emitting layer. Since the metal mask is an expensive member, the metal mask is reused after the metal mask is cleaned with a cleaning agent such as N-methyl-2- pyrrolidone; an acidic solution; an alkaline solution; or the like, followed by a rinsing step with water; and a dewatering step with an alcohol.

Compositions containing hydrochlorofluorocarbon or the like and an alcohol are used as dewatering agent for articles with water on the surface.

Patent Document 1 (JP 2007-188728 A) discloses a regeneration method for a mask, which has a portion composed of silicon and is used for depositing at least one kind of fluorides of an alkali metal, an alkaline earth metal, or a lanthanoid metal by a vapor deposition method, by removing the attached fluoride after use, the regeneration method for a mask including: a first step of removing the fluoride by contacting it with a removing solution having a pH of 7 or lower; a second step of cleaning the mask with a cleaning solution having a pH of higher than 7 and at least 2 higher than the pH of the removing solution; and a third step of drying the mask using i-propanol or the like.

Patent Document 2 (WO 2005/079943 A) describes a dewatering method including: an immersion step of immersing an article with water on its surface in a solvent composition containing at least one selected from hydrochlorofluorocarbons, hydrofluorocarbons, and hydrofluoroethers; and an alcohols as essential components, thus dewatering the article; a specific gravity separation step of separating water from the solvent composition containing water separated from the article by a specific gravity separation method; and a filtration step of filtering the solvent composition, from which water has been separated in the specific gravity separation step, with a coalescer filter to further separate the water remaining in the solvent composition. Citation List Patent Documents

Patent Document 1: JP 2007-188728 A Patent Document 2: WO 2005/079943

Summary Technical Problem

For example, water attached to the metal mask in the cleaning step may adversely affect the vacuum degree in the sputtering step in which the metal mask is used. Therefore, the mask attached with water is generally immersed in an alcohol such as isopropyl alcohol for dewatering. However, water diffused in alcohol is difficult to remove, such that the alcohol that contains a lot of water and has poor dewatering capacity needs to be replaced. However, the alcohol used for such dewatering is generally flammable and is dangerous during replacement work thus difficult to handle. In addition, since flammable alcohol is regulated in some countries, it cannot be used in some cases.

For example, an alcohol-containing fluorinated liquid that can be used as a dewatering agent is generally nonflammable and has excellent handleability, but the fluorinated liquid is a solvent that is more expensive than alcohol. Therefore, if the alcohol-containing fluorinated liquid containing a large amount of water and is no longer suitable for dewatering is replaced in the same manner as the alcohol, the cost can be significantly increased.

When separating a fluorinated liquid from an alcohol-containing fluorinated liquid mixed with water, for example, an oil-water separation filter may be used. However, such a filter is generally designed with a focus on purifying the oil phase at the expense of oil phase yield (yield ratio). Therefore, since the fluorinated liquid is partially contained in the separated aqueous phase, it is difficult to efficiently collect the fluorinated liquid.

The present disclosure provides a method for efficiently recovering a fluorinated liquid from an alcohol-containing fluorinated liquid mixed with water and regenerating it into an alcohol-containing fluorinated liquid that can function as a dewatering agent or the like; and a regeneration system using this regeneration method.

Solution to Problem

One embodiment of the present disclosure provides a regeneration method for an alcohol-containing fluorinated liquid according to one embodiment of the present disclosure includes: step A of supplying, from an effluent tank or an effluent line, effluent containing an alcohol-containing fluorinated liquid mixed with water into a first mixing tank and bringing the effluent into contact with water to prepare a first mixed liquid; step B of filtering the first mixed liquid with a first oil-water separator to separate the first mixed liquid into a first upper layer liquid and a first lower layer liquid; step C of supplying the first upper layer liquid to a waste liquid tank directly or via the first mixing tank and allowing it to stand and separating the first upper layer liquid into a second upper layer liquid and a second lower layer liquid; step D of supplying the second lower layer liquid from the waste liquid tank to the effluent tank or the effluent line; step E of discharging the second upper layer liquid from the waste liquid tank; and step F of adding an alcohol to the fluorinated liquid obtained from the first lower layer liquid.

Another embodiment of the present disclosure provides a method of using an alcohol-containing fluorinated liquid regenerated by using the above-described regeneration method as a dewatering agent for a member used in an organic EL display manufacturing apparatus.

Yet another embodiment of the present disclosure provides a regeneration system for an alcohol-containing fluorinated liquid, including: means A of supplying, from an effluent tank or an effluent line, effluent containing an alcohol-containing fluorinated liquid mixed with water into a first mixing tank and bringing the effluent into contact with water to prepare a first mixed liquid; means B of filtering the first mixed liquid with a first oil-water separator to separate the first mixed liquid into a first upper layer liquid and a first lower layer liquid; means C of supplying the first upper layer liquid to a waste liquid tank directly or via the first mixing tank and allowing it to stand and separating the first upper layer liquid into the second upper layer liquid and the second lower layer liquid; means D of supplying the second lower layer liquid from the waste liquid tank to the effluent tank or the effluent line; means E of discharging the second upper layer liquid from the waste liquid tank; and means F of adding an alcohol to the fluorinated liquid obtained from the first lower layer liquid.

Advantageous Effects of Invention

According to the present disclosure, a method for efficiently recovering a fluorinated liquid from an alcohol-containing fluorinated liquid mixed with water and regenerating it into an alcohol-containing fluorinated liquid that can function as a dewatering agent or the like; and a regeneration system using this regeneration method are provided.

The above descriptions should not be construed as that all aspects of the present disclosure and all advantages of the present disclosure are disclosed.

Brief Description of The Drawings

FIG. l is a flow diagram of a regeneration method for an alcohol-containing fluorinated liquid according to one embodiment of the present disclosure.

FIG. 2 is a flow diagram of a regeneration method for an alcohol-containing fluorinated liquid according to another embodiment of the present disclosure.

Detailed Description

Although representative embodiments of the present invention will now be described in greater detail for the purpose of illustration with reference to the drawings, the present invention is not limited to these embodiments.

In the present disclosure, “effluent” means an alcohol-containing fluorinated liquid in a state of being mixed with water, in which the performance originally possessed by the alcohol-containing fluorinated liquid, such as the dewatering performance, is reduced or eliminated.

The regeneration method for an alcohol-containing fluorinated liquid according to the present disclosure includes step A of supplying, from an effluent tank or an effluent line, effluent containing an alcohol-containing fluorinated liquid mixed with water into a first mixing tank and bringing the effluent into contact with water to prepare a first mixed liquid. Since alcohol is more likely to be mixed with water than fluorinated liquid, when the effluent is brought into contact with water, the alcohol component in the effluent is easily transferred to the contacted water. That is, step A has the effect of reducing the alcohol component in the fluorinated liquid. Therefore, the alcohol-containing fluorinated liquid mixed with water can be separated into a component composed mainly of water and an alcohol; and a component composed of substantially fluorinated liquid containing almost no water and an alcohol.

The water supplied to the mixing tank, is not particularly limited, and for example, tap water, distilled water, ion exchanged water, ultrapure water, and the like can be used.

The effluent generated in a step upstream of the step A, for example, in the dewatering step of the metal mask, may be collected in the effluent tank before being supplied into the first mixing tank or may be supplied directly into the first mixing tank through the effluent line.

The method of supplying water into the first mixing tank is not particularly limited. For example, the water may be supplied directly to the first mixing tank, or if there is another mixing tank to which water is supplied, the water may be supplied from that mixing tank to the first mixing tank.

In some embodiments, an upper layer liquid containing water generated in the filtration step by the oil-water separator can be reused as water used in the mixing tank. Therefore, as described below in step b, the upper layer liquid may be supplied directly to the first mixing tank or, if present, via another mixing tank. If the water supply is insufficient, for example, water may be newly supplied directly into the first mixing tank, or if present, the water may be newly supplied via another mixing tank.

The ratio of the effluent supplied into the first mixing tank and the water in the first mixing tank is not particularly limited and may be appropriately adjusted depending on the size of the first mixing tank to be used and the like. For example, the ratio of the effluent supplied into the first mixing tank to the water in the first mixing tank may be from 1 :5 to 5:1, preferably from 1:3 to 3:1, more preferably from 1:2 to 2:1, and particularly preferably 1 : 1 from the viewpoint of the purification efficiency of the fluorinated liquid.

The method of contacting effluent with water is not particularly limited, and for example, the methods of (1) to (6) below can be employed alone or in combination of two or more thereof and can be performed by combining some of the methods of (1) to (6) as appropriate. For example, a physical stirring method using vibration, a stirring blade, or the like; a stirring method using air; a stirring method using ultrasonic waves; or the like, which are described in (3), (5), or (6), may be applied to the method (1) or (2).

(1) A method of dropping or spraying effluent from above the first mixing tank containing water.

(2) A method of adding water from the lower side of the first mixing tank containing effluent.

(3) A method of physically stirring the first mixing tank containing effluent and water by vibration or using a stirring bar or stirring blades.

(4) A method of connecting a lower part and an upper part of the first mixing tank with a pipe or the like in the first mixing tank containing effluent and water; and moving a mixed liquid composed of the effluent and water in the first mixing tank from the lower part to the upper part or from the upper part to the lower part by a pump or the like.

(5) A method of mixing a mixed liquid by blowing gas such as air into the first mixing tank containing effluent and water for bubbling.

(6) A method of mixing a mixed liquid by applying ultrasonic waves into the first mixing tank containing effluent and water.

The regeneration method of the present disclosure includes step B of filtering the first mixed liquid with a first oil-water separator to separate the first mixed liquid into a first upper layer liquid (may be referred to as “first waste liquid”) and a first lower layer liquid (may be referred to as “purified liquid”). The mixed liquid obtained through the step A has a form like a cloudy water-in-oil emulsion in which water droplets (aqueous phase) are dispersed in a fluorinated liquid (oil phase). By filtering the first mixed liquid in such a state with the first oil-water separator, it can be separated into the first upper layer liquid (first waste liquid) to be an aqueous phase and the first lower layer liquid (purified liquid) to be an oil phase). Here, the separation speed of the aqueous phase and the oil phase by the oil-water separator is higher than that of stationary separation operation. However, the oil-water separator is, for example, designed to focus on oil phase purification at the expense of oil phase yield or may be insufficient for separation operation such as centrifugation; therefore the first upper layer liquid (first waste liquid) contains a small amount of the fluorinated liquid in an emulsified state in water.

The oil-water separator is not particularly limited as long as it is a device capable of separating a fluorinated liquid and water and may be, for example, a coalescer filter or a centrifugal oil-water separator. Among them, the coalescer filter is advantageous from the viewpoint of productivity. The coalescer filter is a filter that separates water droplets captured by an ultrafme fiber filter into oil and water by aggregating and coarsening them.

In some embodiments, the regeneration method of the present disclosure may further include step b, in which the first upper layer liquid is returned into the first mixing tank, following step B. The first upper layer liquid obtained through step B contains not only water but also an alcohol component and a fluorinated liquid component. When the ratio of these components, especially the ratio of the alcohol component, is low, the water in the first upper layer liquid can exhibit the ability to transfer the alcohol component from the effluent. Therefore, such a first upper layer liquid may be returned to the first mixing tank without being supplied to a waste liquid tank and reused as water for transferring the alcohol component from the effluent. The number of times the first upper layer liquid is reused is not particularly limited and may be appropriately set in consideration of the performance of transferring the alcohol component from the effluent.

The regeneration method of the present disclosure includes step C of supplying the first upper layer liquid (first waste liquid) to the waste liquid tank directly or via the first mixing tank and allowing it to stand and separating the first upper layer liquid into a second upper layer liquid (may be referred to as “final waste liquid”) and a second lower layer liquid (may be referred to as “recovered liquid from the first waste liquid”). The first upper layer liquid (first waste liquid) obtained through step B may be directly supplied to the waste liquid tank. Alternatively, as described above, since the first upper layer liquid may be reused as water for transferring the alcohol component from the effluent in the first mixing tank, the first upper layer liquid (first waste liquid) determined not suitable for reuse may be supplied to the waste liquid tank via the first mixing tank.

As described above, the first upper layer liquid (first waste liquid) obtained through the filtration step of step B contains a small amount of fluorinated liquid. By storing and allowing such a first upper layer liquid (first waste liquid) to stand in the waste liquid tank, it can be separated into the second upper layer liquid (final waste liquid) and the second lower layer liquid (recovered liquid from the first waste liquid). The stationary separation has a slower separation speed than the above-described oil-water separator, but is excellent in the separation performance between the aqueous phase and the oil phase. This stationary operation can contribute to the reduction or suppression of the disposal rate of the expensive fluorinated liquid.

The stationary time may be, for example, 1 hour or longer, 6 hours or longer, 12 hours or longer, or 1 day or longer. The upper limit of the stationary time is not particularly limited and may be, for example, 1 week or less, 5 days or less, or 3 days or less.

The stationary operation may be typically carried out at room temperature, but it may be carried out while cooling to about 0 to 15°C to promote separation.

The regeneration method of the present disclosure includes step D of supplying the second lower layer liquid (recovered liquid from the first waste liquid) from the waste liquid tank to the effluent tank or the effluent line. The second lower layer liquid (recovered liquid from the first waste liquid) obtained through the stationary operation in step C contains a high amount of fluorinated liquid. The second lower layer liquid (recovered liquid from the first waste liquid) may be supplied again to a fluorinated liquid purification line by, for example, supplying the second lower layer liquid to the effluent tank or the effluent line from the bottom of the waste liquid tank by using gravity or a pump; or by suctioning the second lower layer liquid with a pipe extending from above the waste liquid tank to near the bottom of the waste liquid tank and supplying it to the effluent tank or the effluent line. Therefore, the disposal rate of expensive fluorinated liquid can be reduced or suppressed. In other words, the yield of expensive fluorinated liquid can be improved.

All the waste liquid supplied to the waste liquid tank had been discarded.

However, the regeneration method of the present disclosure allows high level of recovery of the expensive fluorinated liquid contained in the waste liquid and thus can contribute to: reduction of manufacturing cost of organic EL displays and other articles manufactured using a fluorinated liquid; and reduction of environmental pollution.

In some embodiments, the waste liquid tank may include a sensor for detecting the interface between the aqueous phase containing water and an alcohol corresponding to the second upper layer liquid (final waste liquid) and the oil phase containing the fluorinated liquid corresponding to the second lower layer liquid (recovered liquid from the first waste liquid). The sensor is not particularly limited and, for example, may be a float liquid level sensor or an inductive level sensor.

The sensor may be installed at a position where the interface level between the aqueous phase and the oil phase in the waste liquid tank can be grasped. The sensor may be set such that, for example, when the oil phase interface rises to a predetermined level, a valve attached to a pipe extending from the bottom of the waste liquid tank is opened by a signal from the sensor, the pump is operated to supply the oil phase to the effluent tank or the effluent line, and the pump is stopped by a signal from the sensor when the oil phase interface drops to a predetermined level, whereby the valve is closed. For example, when a discharge port for discharging the second upper layer liquid (final waste liquid) is provided on the lower side surface of the waste liquid tank, the vicinity of the lower side of the discharge port may be set as the predetermined rising level of the oil phase interface. For example, the detection limit of the interface level of the aqueous phase and the oil phase in the waste liquid tank may be set as the predetermined lowering level of the oil phase interface.

The regeneration method of the present disclosure includes step E of discharging the second upper layer liquid (final waste liquid) from the waste liquid tank. The second upper layer liquid (final waste liquid) may be discharged from the waste liquid tank by sucking the second upper layer liquid (final waste liquid) from the waste liquid tank using a pump or the like. However, from the viewpoint of efficiency, it is advantageous to provide a discharge port for discharging the aqueous phase on the lower side surface of the waste liquid tank and to discharge the second upper layer liquid (final waste liquid) through the discharge port using gravity or a pump.

The regeneration method of the present disclosure includes step F of adding an alcohol to the fluorinated liquid obtained from the first lower layer liquid (purified liquid). The “fluorinated liquid obtained from the first lower layer liquid (purified liquid)” may be the fluorinated liquid itself of the first lower layer liquid (purified liquid) or means a fluorinated liquid of the lower layer liquid produced by further filtering the first lower layer liquid (purified liquid) with, for example, an additional oil-water separator installed downstream of filtration step B. Both mean fluorinated liquids in a dry state, which may permit slight amounts of water and an alcohol component. The fluorinated liquid may be defined by, for example, the amount of water measured using a Karl Fischer moisture meter and the purity by a gas chromatography method.

The water amount in the obtained fluorinated liquid may be, for example, 200 ppm or less, 150 ppm or less, 100 ppm or less, or 80 ppm or less. The lower limit of the water amount is not particularly limited, but may be, for example, 0 ppm or more, 5 ppm or more, or 10 ppm or more.

The purity of the obtained fluorinated liquid may be 95% or higher, 97% or higher, or 98% or higher and may be 100% or lower or lower than 100%.

In addition, the fluorinated liquid obtained from the first lower layer liquid (purified liquid) may also be defined by mixing the liquid with the same weight of ultrapure water to extract impurities in the fluorinated liquid into the ultrapure water; and measuring the pH and fluorine ion concentration of the extract. The pH may be 4.5 or higher, 4.7 or higher, or 5.0 or higher and may be 6.0 or lower, 5.8 or lower, or 5.6 or lower. The fluorine ion concentration may be 1.0 ppm or lower, 0.5 ppm or lower, 0.3 ppm or lower, or 0.1 ppm or lower and may be 0 ppm or higher or higher than 0 ppm.

The fluorinated liquid obtained from the first lower layer liquid (purified liquid) has a much lower water amount than that in the effluent and is in a dry state, so that a dry alcohol-containing fluorinated liquid that can function as a dewatering agent or the like can be regenerated by adding an alcohol to the fluorinated liquid. The water amount of the regenerated alcohol-containing fluorinated liquid may also be measured using a Karl Fischer moisture meter. The water amount may be, for example, 500 ppm or less, 300 ppm or less, 200 ppm or less, or 150 ppm or less. The lower limit of the water amount is not particularly limited, but may be, for example, 10 ppm or greater, 30 ppm or greater, or 50 ppm or greater.

In some embodiments, step F may be performed by supplying the first lower layer liquid into a second mixing tank and bringing the first lower layer liquid into contact with water to prepare a second mixed liquid; filtering the second mixed liquid with a second oil-water separator to separate the second mixed liquid into a third upper layer liquid and a third lower layer liquid; and adding an alcohol to the fluorinated liquid. When the water amount and the purity of the fluorinated liquid of the third lower layer liquid do not fall within the ranges described above, mixing operation with the mixing tank and subsequent filtering operation with the oil-water separator may be further added once or more. Here, the mixing operation with the mixing tank and the filtering operation with the oil-water separator may be performed in the same manner as the above-described step A and step B.

The fluorinated liquid of the first lower layer liquid (purified liquid) obtained by filtering with the first oil-water separator is a transparent liquid, such that it does not contain large water droplets. However, the transparent fluorinated liquid may contain dissolved water molecules. In this case, even if a dry alcohol is added, the alcohol molecules are associated with the dissolved water molecules, and the fluorinated liquid may not sufficiently function as a dewatering agent. In such cases, it is advantageous to perform the mixing operation and the filtering operation twice or more, because the dissolved water and an alcohol component in the fluorinated liquid can be further reduced or removed.

In a case where the mixing operation and the filtering operation are to be performed only once, the amount of water to be charged into the first mixing tank needs to be relatively large, and thus the mixing tank also needs to be large. On the other hand, when the mixing operation and the filtering operation are performed twice or more, the total amount of water used in the mixing tank can be lower and the tank can be smaller than the case where the mixing operation and the filtering operation are performed only once, which has environmental and facility design advantages.

The upper layer liquid (aqueous phase) generated in the second and subsequent filtering operations may be supplied to a mixing tank located upstream of the filtration step and reused as water for transferring the alcohol component from the fluorinated liquid. For example, the third upper layer liquid generated from the second oil-water separator may be supplied to the second mixing tank to be reused or may be supplied directly or via the second mixing tank to the first mixing tank to be reused. When the amount of water supplied to the mixing tank is insufficient for reuse, water may be newly supplied into the mixing tank. The upper layer liquid determined not to be suitable for reuse may be supplied to the waste liquid tank directly or via the first mixing tank.

The above-described steps may be appropriately connected, for example, through a pipe or the like, and a valve or a pump that operates manually or automatically may be appropriately installed in each pipe.

The effluent that can be regenerated by the regeneration method of the present disclosure is an alcohol-containing fluorinated liquid mixed with water. Examples of the usable fluorinated liquid include hydrofluoroethers, hydrofluoroolefms, and mixtures thereof. The fluorinated liquid may contain other fluorinated liquids (for example, hydrochlorofluorocarbons, hydrofluorocarbons, and the like) in addition to the fluorinated liquid described above, but preferably does not contain other fluorinated liquid from the viewpoint of purification efficiency and the like.

Among the fluorinated liquids described above, from the perspective of separation performance and purification efficiency of a phase containing an aqueous phase and a fluorinated liquid, the use of hydrofluoroether is preferable. The hydrofluoroether is a compound containing an oxygen atom that is ether bondable between carbon atoms of hydrofluorocarbon. The number of ether bondable oxygen atoms contained in one molecule of the hydrofluoroether may be one or may be two or more, but is preferably one or two, and more preferably one from the viewpoint of ease of use as a dewatering agent and stability. A molecular structure of the hydrofluoroether only needs to be a chain and may be a straight chain or a branched chain, but from the perspective of purification efficiency and the like, a straight chain is preferable.

Examples of the hydrofluoroether include segregate-type hydrofluoroethers such as C4F9OCH3, C4F9OCH2CH3 C5F11OCH3, C5F11OCH2CH3, C6F13OCH3, C6F13OCH2CH3, C7F15OCH3, C7F15OCH2CH3, CsFnOCft, C8F17OCH2CH3, C9F19OCH3, C9F19OCH2CH3, C10F21OCH3, and C10F21OCH2CH3; and hydrofluoroethers such as CF3CH2OCF2CF2H, CF3CHFOCH2CF3, CF3CH2OCF2CFHCF3, CHF2CF2CH2OCF2CF2H, C3F7OC3F6OCFHCF3, CF₃CF(CF3)CF(0CH3)CF₂CF3, CF3CF(CF3)CF(0C2H₅)CF₂CF3, CF2(0CH₂CF3)CF₂H, CF₂(OCH₂CF3)CFHCF3, CF₂(OCH2CF2CF2H)CF₂H, and CF2(OCH2CF2CF2H)CFHCF_3. Such hydrofluoroethers can be used alone or in combination of two or more thereof.

Among them, segregate-type hydrofluoroether has low solubility in water, and in a case of being brought into contact with water, the proportion dissolved in the aqueous phase can be reduced as compared with other hydrofluoroethers or hydrofluoroolefins, and thus it is easy to separate the aqueous phase from the phase containing the fluorinated liquid. Among the segregate-type hydrofluoroethers, C4F9OCH3 or C4F9OCH2CH3 is more preferable. Here, the “segregate-type” refers to a structure in which one side is completely fluorinated and the other side is composed of carbon and hydrogen with an ether bond interposed therebetween.

The hydrofluoroolefin is intended to be a compound in which one or more hydrogen atoms in the olefin are substituted with a fluorine atom. The number of fluorine atoms contained in the hydrofluoroolefin is not particularly limited and may be one or more or two or more; and ten or less or six or less. The hydrofluoroolefin may be either type E (trans type) or type Z (cis type). The hydrofluoroolefin may be hydrochlorofluoroolefm. The hydrochlorofluoroolefm is intended to be a compound in which one or two or more hydrogen atoms in the olefin are substituted with fluorine atoms, and one or two or more other hydrogen atoms in the olefin are substituted with chlorine atoms. The number of chlorine atoms in the hydrochlorofluoroolefm is not particularly limited, and can be one or more, and five or less or three or less.

Examples of the hydrofluoroolefin having no chlorine atom include CF3-CH=CH2, CF₃-CF=CH₂, CHF₂-CH=CHF, CHF₂-CF=CH₂, CH₂F-CH=CF₂, CH₂F-CF=CHF, CH3- CF=CF₂, CF3-CH=CH-CF₃, CF3-CH=CF-CH₃, CF3-CF=CH-CH₃, CF₃-CH=CH-CH₂F, CHF₂-CF=CF-CH₃, CHF₂-CF=CH-CH₂F, CHF₂-CH=CF-CH₂F, CHF₂-CH=CH-CHF₂, CH₂F-CF=CF-CH₂F, CH₂F-CH=CH-CF₃, CH₂F-CF=CH-CHF₂, CF₃-CH₂-CF=CH₂, CF₃- CHF-CH=CH₂, CF₃-CH₂-CH=CHF, CHF₂-CF₂-CH=CH₂, CHF₂-CHF-CF=CH₂, CHF₂- CHF-CH=CHF, CH₂F-CF₂-CF=CH₂, CH₂F-CF₂-CH=CHF, CH₂F-CHF-CF=CHF, CHZF- CHF-CF=CF₂, CH₂F-CH₂-CF=CF₂, CH₃-CF₂-CF=CHF, and CH₃-CF₂-CH=CF₂. Examples of the hydrofluoroolefm having a chlorine atom (that is, hydrochlorofluoroolefm) include

CF₃-CH=CHC1, CHF₂-CF=CHCI, CHF₂-CH=CFCI, CHF₂-CCI=CHF, CH₂F-CC1=CF₂, CHFC1-CF=CHF, CH₂C1-CF=CF₂, and CF₃-CC1=CH₂. A particularly preferable hydrofluoroolefm having a chlorine atom is CF₃-CH=CHC1. Hydrofluoroolefms (including hydrochlorofluoroolefms) may be used alone or in combination of two or more of them.

Examples of usable alcohols include alcohols having 1 to 4 carbon atoms, specifically, methanol, ethanol, isopropyl alcohol and butanol. These may be used alone or in combination of two or more of them.

From the viewpoint of purification efficiency and dewatering performance, a combination of hydrofluoroether as the fluorinated liquid and isopropyl alcohol as the alcohol is preferable.

The amount of the alcohol added to the fluorinated liquid purified in the process of the regeneration method of the present disclosure is not particularly limited and may be appropriately adjusted depending on the intended use and the like of the alcohol- containing fluorinated liquid. For example, when preparing an alcohol-containing fluorinated liquid having nonflammability and dewatering performance, the amount of alcohol added with reference to the total amount of the alcohol-containing fluorinated liquid may be 10% by mass or less, 7% by mass or less, or 5% by mass or less and may be 1% by mass or greater, 2% by mass or greater, or 3% by mass or greater.

The regeneration system for an alcohol-containing fluorinated liquid according to one embodiment of the present disclosure includes: means A of supplying, from an effluent tank or an effluent line, effluent containing an alcohol-containing fluorinated liquid mixed with water into a first mixing tank and bringing the effluent into contact with water to prepare the first mixed liquid; means B of filtering the first mixed liquid with a first oil-water separator to separate the first mixed liquid into a first upper layer liquid (first waste liquid) and a first lower layer liquid (purified liquid); means C of supplying the first upper layer liquid (first waste liquid) to a waste liquid tank directly or via the first mixing tank and allowing it to stand and separating the first upper layer liquid into the second upper layer liquid (final waste liquid) and the second lower layer liquid (recovered liquid from the first waste liquid); means D of supplying the second lower layer liquid (recovered liquid from the first waste liquid) from the waste liquid tank to the effluent tank or the effluent line; means E of discharging the second upper layer liquid (final waste liquid) from the waste liquid tank; and means F of adding an alcohol to the fluorinated liquid obtained from the first lower layer liquid (purified liquid). Examples of the fluorinated liquid, alcohol, and water usable in the regeneration system include the same ones as those in the above-described regeneration method. The regeneration system of the present disclosure can similarly exhibit the effects and the like described in the above- described regeneration method.

Means A to F in the regeneration system of the present disclosure correspond to steps A to F in the regeneration method, and any means described later, such as means b also corresponds to any step (for example, step b) in the regeneration method. Therefore, the matters relating to each step in the above-described regeneration method can be similarly applied to each means in the regeneration system. Each means in the regeneration system of the present disclosure is not particularly limited as long as it is a means capable of performing each of these steps.

In some embodiments, the regeneration system of the present disclosure may further include, following means B, means b for returning the first upper layer liquid into the first mixing tank.

In some embodiments, means F in the regeneration system of the present disclosure may be performed by supplying the first lower layer liquid (purified liquid) into the second mixing tank to bring it into contact with water to prepare the second mixed liquid, filtering the second mixed liquid with the second oil-water separator to separate the second mixed liquid into the third upper layer liquid and the third lower layer liquid, and adding an alcohol to the fluorinated liquid obtained from the third lower layer liquid.

In some embodiments, the third upper layer liquid may be supplied to the second mixing tank or may be supplied to the first mixing tank directly or via the second mixing tank. In some embodiments, the waste liquid tank in the regeneration system of the present disclosure may include a sensor for detecting the interface between an aqueous phase containing water and an alcohol corresponding to the second upper layer liquid (final waste liquid) and an oil phase containing the fluorinated liquid corresponding to the second lower layer liquid (recovered liquid from the first waste liquid).

For example, the material, volume, shape, quantity, and location of the effluent tank, the mixing tank, the waste liquid tank, and the container for storing the oil-water separator used in each means of the regeneration system of the present disclosure may be appropriately selected according to the intended use of the regeneration system, the use environment, and the like.

The regeneration method and regeneration system for an alcohol-containing fluorinated liquid of the present disclosure can be appropriately used, for example, online or offline in various production lines.

When the regeneration method and the regeneration system of the present disclosure are used online, these may be appropriately configured so that the regenerated alcohol-containing fluorinated liquid can be charged again in, for example, the dewatering step.

When the regeneration method and regeneration system of the present disclosure are used offline, the effluent of an alcohol-containing fluorinated liquid mixed with water generated in, for example, a dewatering step in an organic EL display manufacturing line is regenerated to a dry alcohol-containing fluorinated liquid in another line, and then it can be reused in the dewatering step of the organic EL display production line. On the other hand, the regenerated alcohol-containing fluorinated liquid may also be used as a cleaning agent, a rinse liquid, a dewatering agent, or the like for purposes other than the organic EL display. Alternatively, the fluorinated liquid before addition of alcohol, which is purified by the regeneration method and the regeneration system of the present disclosure, may also be used as a cleaning agent, a rinse liquid or the like in various applications.

The alcohol-containing fluorinated liquid regenerated using the regeneration method or the regeneration system of the present disclosure is useful as, but not limited to, a cleaning agent, a rinse liquid, and a dewatering agent used in various applications such as organic EL displays, electronic parts, precision parts, metal parts, and printed wiring boards. In some embodiments, the alcohol-containing fluorinated liquid regenerated using the regeneration method or the regeneration system of the present disclosure is used in an organic EL display manufacturing apparatus and is useful as a dewatering agent for various members such as metal masks and deposition-proof plates exposed to cleaning work, rinsing work, dewatering work, and the like. Here, the “deposition-proof plate” refers to a member disposed inside a vacuum chamber of a vacuum evaporation apparatus used in the manufacture of an organic EL display and is a member that can be removed and cleaned to prevent contamination of the vacuum chamber from the three colors of red (R), green (G), and blue (B), which are evaporation sources.

Examples

Specific embodiments of the present invention will be exemplified in the following examples, but the present invention is not limited to these embodiments.

Products and the like used in the examples are shown in Table 1 below.

[Table 1]

The physical properties of various liquids were evaluated using the following methods.

(pH test)

After placing the evaluation sample in a clean plastic bottle, the same weight of ultrapure water was further added and shaken for 2 hours using a shaker. Then, the pH of the aqueous phase (upper layer) was measured. The pH was measured with a 920A pH meter manufactured by Orion Research Inc. The ultrapure water was produced with an ultrapure water production machine (ELIX ESSENTIAL 10, available from Merck KGaA).

(Fluoride ion concentration test)

After placing the evaluation sample in a clean plastic bottle, the same weight of ultrapure water was further added and shaken for 2 hours using a shaker. Then, the fluorine ion concentration of the aqueous phase (upper layer) was measured. The fluorine ion concentration was measured with a 920A pH meter manufactured by Orion Research Inc. The ultrapure water was produced with an ultrapure water production machine (ELIX ESSENTIAL 10, available from Merck KGaA).

(Water amount test)

The water amount in the sample was measured using a Karl Fischer moisture meter CA-21 manufactured by Mitsubishi Chemical Corporation.

(Appearance evaluation test)

The appearance of the evaluation sample was visually observed.

(Component ratio evaluation test)

The content ratio of each component of the evaluation sample (IPA component, fluorinated liquid component, and high-boiling point solvent component) was evaluated by gas chromatography using 7890A manufactured by Agilent Technologies. The measurement conditions of the gas chromatography method are as follows. Here, the high- boiling point solvent component means, for example, a high-boiling point component having a boiling point of 150°C or higher such as cyclohexanone, N-methylpyrrolidone, and decane:

Column Type: HP-1301

Column length: 60 m

Column Temperature: 260°C

Type of carrier gas: Helium gas

Flow rate of carrier gas: 205 mL/min

Sample injection volume: 1 pL Example 1

A regeneration system was constructed according to the flow chart shown in FIG.

2. NOVEC (™) 71IPA, to which distilled water had been added for pseudo-contamination, was used as effluent 1 charged into an effluent tank 2, EUTEC (™) FS manufactured by Asahi Kasei Corporation, which is a coalescer filter, was used as a first oil-water separator 4 and a second oil-water separator 7, and Float Switch HL-MR manufactured by Watty Corporation, which is a float liquid level sensor, was used as a detection sensor 11 installed in a waste liquid tank 8.

An amount of 90 liters of the effluent 1 was charged into the effluent tank 2. An amount of 10 liters of distilled water 5 was charged into a second mixing tank 6, 10 liters of this distilled water was charged into a first mixing tank 3 through the second mixing tank 6, and then 10 liters of distilled water was further charged into the second mixing tank 6.

An amount of 10 liters of effluent from the effluent tank 2 was sprayed to the first mixing tank 3 with a spraying nozzle to mix the effluent with distilled water, thus preparing a first mixed liquid. The obtained first mixed liquid was filtered by the first oil- water separator 4 to be separated into an aqueous phase containing water and IPA and an oil phase containing a fluorinated liquid containing a small amount of IPA.

Subsequently, the separated aqueous phase was returned to the first mixing tank 3 to be reused, and the oil phase was sprayed to the second mixing tank 6 with a spraying nozzle to mix the oil phase and distilled water, thus preparing a second mixed liquid. The obtained second mixed liquid was filtered by the second oil-water separator 7 to be separated into an aqueous phase containing water and a small amount of IPA and an oil phase containing a fluorinated liquid, and a purified fluorinated liquid was collected. The separated aqueous phase was returned to the second mixing tank 6 and reused.

From this state, 10 litter of effluent was further charged from the effluent tank 2 into the first mixing tank 3, and the purified fluorinated liquid was collected in the same manner as above. This series of operations was performed up to three times, and when the purified fluorinated liquid for three times was collected, the cloudy aqueous phase returned to the first mixing tank 3 was discharged to the waste liquid tank 8. Subsequently, the aqueous phase returned to the second mixing tank 6 was charged into the first mixing tank 3, and 10 liters of the distilled water 5 was newly charged into the second mixing tank. The series of operations up to this point was repeated until the effluent in the effluent tank 2 was exhausted.

The aqueous phase discharged into the waste liquid tank 8 was allowed to stand for one day. When the detection sensor 11 detected the separation into the aqueous phase containing water and IPA and the oil phase containing the fluorinated liquid, a valve 9 was automatically opened and a pump 10 was automatically operated to return the oil phase containing the fluorinated liquid to the effluent tank 2. When the oil phase could not be confirmed by the detection sensor 11, the pump 10 was automatically stopped and the valve 9 was automatically closed. Next, the aqueous phase containing water and IPA was discharged from the discharge port of the waste liquid tank 8.

Table 2 summarizes the amounts of effluent charged into this system, purified fluorinated liquid, discharged waste liquid (water and IPA), and fluorinated liquid returned to the effluent tank. Table 3 shows the physical property evaluation results of the effluent, the purified fluorinated liquid, and the IPA-containing fluorinated liquid regenerated by adding 5% by mass of IPA (Tokuso IPA (™), available from Tokuyama Corporation) to the purified fluorinated liquid; and, as reference examples, the physical property evaluation results of commercially available NOVEC (™) 71 IPA without pseudo contamination and commercially available NOVEC (™) 7100 that is free from IPA and constitutes NOVEC (™) 71IPA. In Table 3, the purified fluorinated liquid is referred to as “purified fluorinated liquid”, and the IPA-containing fluorinated liquid regenerated by adding 5% by mass of IPA to the purified fluorinated liquid is referred to as “regenerated IPA-containing fluorinated liquid”.

[Table 2]

[Table 3]

It will be apparent to those skilled in the art that various modifications can be made to the embodiments and the examples described above without departing from the basic principles of the present invention. In addition, it will be apparent to those skilled in the art that various improvements and modifications of the present invention can be carried out without departing from the spirit and the scope of the present invention.

Reference Signs List

1 Effluent

2 Effluent tank

3 First mixing tank

4 First oil-water separator

5 Distilled water

6 Second mixing tank

7 Second oil-water separator

8 Waste liquid tank

9 Valve

10 Pump

11 Detection sensor

Claims

What is claimed is:

1. A regeneration method for an alcohol-containing fluorinated liquid comprising: step A of supplying, from an effluent tank or an effluent line, effluent containing an alcohol-containing fluorinated liquid mixed with water into a first mixing tank and bringing the effluent into contact with water to prepare a first mixed liquid; step B of filtering the first mixed liquid with a first oil-water separator to separate the first mixed liquid into a first upper layer liquid and a first lower layer liquid; step C of supplying the first upper layer liquid to a waste liquid tank directly or via the first mixing tank and allowing it to stand and separating the first upper layer liquid into a second upper layer liquid and a second lower layer liquid; step D of supplying the second lower layer liquid from the waste liquid tank to the effluent tank or the effluent line; step E of discharging the second upper layer liquid from the waste liquid tank; and step F of adding an alcohol to the fluorinated liquid obtained from the first lower layer liquid.

2. The regeneration method according to claim 1, further comprising step b of returning the first upper layer liquid into the first mixing tank, following the step B.

3. The regeneration method according to claim 1 or 2, wherein the step F is performed by supplying the first lower layer liquid into a second mixing tank and bringing the first lower layer liquid into contact with water to prepare a second mixed liquid, filtering the second mixed liquid with a second oil-water separator, separating the second mixed liquid into a third upper layer liquid and a third lower layer liquid, and adding an alcohol to the fluorinated liquid obtained from the third lower layer liquid.

4. The regeneration method according to claim 3, wherein the third upper layer liquid is supplied to the second mixing tank or is supplied directly or via the second mixing tank to the first mixing tank.

5. The regeneration method according to any one of claims 1 to 4, wherein the waste liquid tank comprises a sensor that detects an interface between the second upper layer liquid and the second lower layer liquid.

6. The regeneration method according to any one of claims 1 to 5, wherein the oil- water separator is a coalescer filter.

7. The regeneration method according to any one of claims 1 to 6, wherein the fluorinated liquid is hydrofluoroether, and the alcohol is isopropyl alcohol.

8. A method of using the alcohol-containing fluorinated liquid regenerated by the regeneration method described in any one of claims 1 to 7 as a dewatering agent for a member used in an organic EL display manufacturing apparatus.

9. The method according to claim 8, wherein the member is a metal mask or a deposition-proof plate.

10. A regeneration system for an alcohol-containing fluorinated liquid, comprising: means A of supplying, from an effluent tank or an effluent line, effluent containing an alcohol-containing fluorinated liquid mixed with water into a first mixing tank and bringing the effluent into contact with water to prepare a first mixed liquid; means B of filtering the first mixed liquid with a first oil-water separator to separate the first mixed liquid into a first upper layer liquid and a first lower layer liquid; means C of supplying the first upper layer liquid to a waste liquid tank directly or via the first mixing tank and allowing it to stand and separating the first upper layer liquid into the second upper layer liquid and the second lower layer liquid; means D of supplying the second lower layer liquid from the waste liquid tank to the effluent tank or the effluent line; means E of discharging the second upper layer liquid from the waste liquid tank; and means F of adding an alcohol to the fluorinated liquid obtained from the first lower layer liquid.

11. The regeneration system according to claim 10, further comprising means b for returning the first upper layer liquid into the first mixing tank, following the means B.

12. The regeneration system according to claim 10 or 11, wherein the means F is performed by supplying the first lower layer liquid into a second mixing tank and bringing the first lower layer liquid into contact with water to prepare a second mixed liquid, filtering the second mixed liquid with a second oil-water separator, separating the second mixed liquid into a third upper layer liquid and a third lower layer liquid, and adding an alcohol to the fluorinated liquid obtained from the third lower layer liquid.

13. regeneration system according to claim 12, wherein the third upper layer liquid is supplied to the second mixing tank or is supplied directly or via the second mixing tank to the first mixing tank.

14. The regeneration system according to any one of claims 10 to 13, wherein the waste liquid tank comprises a sensor that detects an interface between the second upper layer liquid and the second lower layer liquid.