JP2610062B2 - Steam drying method and its apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention is effectively applied to, for example, drying of liquid crystal substrates, printed wiring boards, semiconductor wafers, precision electronic components such as electronic components, lenses and the like after water washing. A method of removing moisture from a moisture-containing steam by a steam compressor and a gas separation membrane module to obtain a reusable dried lower alcohol vapor, and steam-drying an object to be dried with the dried steam; and The present invention relates to a steam drying apparatus capable of performing the steam drying method.

[Description of Prior Art]

Conventionally, a steam drying method of arranging an object to be dried in steam generated by heating a solvent such as isopropanol and drying the object to be dried only with steam from the solvent is disclosed in Japanese Patent Application Laid-Open No. 56-1680.
Japanese Patent Application Laid-Open No. 58-207638 discloses a related device.

Further, the apparatus for steam drying is a processing apparatus provided with a steam generating section for a processing liquid such as lower alcohol, a processing space and a collecting section for a treated water-containing processing liquid after the processing. In order to regenerate the water-containing treatment liquid in the collection unit, a purification unit having a water removal unit and a distillation unit is provided, and the purified treatment liquid can be introduced into the steam generation unit. A steam drying device is disclosed in
No. 106630, and in the known document, using the steam drying apparatus, a processing solution containing water generated by steam drying of a semiconductor wafer or the like is treated with a water removing means and a distillation means. It is disclosed that the regenerated processing solution is regenerated by a refining means and the regenerated processing liquid is circulated and used in a steam generation unit (steam drying tank).

However, the above-mentioned known steam drying apparatus is not specifically disclosed as a means for removing water from the water-containing treatment liquid, and a means for removing water from the liquid water-containing treatment liquid may be a desiccant or the like. However, its processing capacity is limited, and in that case, regeneration of the desiccant is necessary.

Further, in the above-described known steam drying apparatus, the processing liquid such as lower alcohol stored in the bottom of the steam processing tank gradually increases the water concentration, and finally, the steam in the steam processing tank is increased at a high rate. Due to the inclusion, there is a problem in that it is not possible to generate a high-concentration lower alcohol vapor which can effectively dry the object to be dried.

[Problems to be solved]

The present invention provides, in a steam drying method, a method for easily producing a dried lower alcohol vapor by removing water from a water-containing vapor extracted from a steam treatment tank with low energy and a high removal rate, and drying the lower alcohol. It is an object of the present invention to provide a new steam drying method capable of efficiently performing steam drying by directly spraying steam on an object to be dried in a steam processing tank, and to provide a steam drying apparatus therefor.

[Means to solve the problem]

The first invention of this application is as follows: (A) A wet object to be dried is placed inside a steam treatment tank having a lower alcohol reservoir at the bottom thereof;
The object to be dried is brought into contact with the lower alcohol vapor generated from the liquid reservoir and a non-permeate vapor described later and the object to be dried, and the object to be dried is steam-dried. (B) The water-containing steam in the steam treatment tank is extracted. After pressurizing to 0.1 to 10 kg / cm ² G by a steam compressor, the pressurized steam is supplied to a gas separation membrane module. (C) In the gas separation membrane module, the mixed pressurized steam is combined with a gas separation membrane. (D) removing the permeated vapor from the permeate side of the gas separation membrane and taking out the dried non-permeate vapor from the supply side of the gas separation membrane; To a steam drying method characterized by spraying water.

Further, a second invention provides: (a) a steam treatment tank in which a liquid reservoir for lower alcohol is formed at a bottom portion; and (b) a steam compressor for pressurizing moisture-containing steam extracted from the steam treatment tank. (C) a gas separation membrane module for separating and removing moisture from the pressurized steam; (d) a pipe for supplying dried non-permeated steam taken out from the gas separation membrane module into a steam treatment tank; The present invention relates to a steam drying apparatus comprising a nozzle provided at a tip of a pipe for spraying on a material to be dried.

Hereinafter, each invention of this application will be described in more detail with reference to the drawings.

FIG. 1 and FIG. 2 are flowcharts each schematically showing an example of an apparatus for carrying out the present invention.

In the steam drying method of the present invention, as shown in FIGS. 1 and 2, a steam treatment tank 1 in which a lower alcohol liquid reservoir 2 is formed at the bottom and a heater 3 is provided outside the lower reservoir 2 is used. Is done. In the present invention, as shown in FIG. 2, the vapor processing tank 1 is provided with a collecting section 5 for collecting a condensed liquid in which the vapor of the lower alcohol comes into contact with the material 4 to be dried and is condensed. Good.

In the steam drying method of the present invention, as shown in FIG. 1, first, in the steam processing tank 1, the object 4 to be dried placed inside the steam processing tank 1 by the holder 6 for holding the object 4 to be dried. Is brought into contact with steam generated from the lower alcohol liquid (treatment liquid) in the liquid reservoir and "dry lower alcohol vapor (unpermeated vapor)" taken out from the gas separation membrane module 30 and sprayed to perform steam drying. You do it.

In the steam drying method of the present invention, in FIG. 2, the water-containing condensed processing liquid condensed on the surface of the object 4 to be dried in the steam processing tank 1 and collected by the collection unit 5 is used as a liquid storage unit. Or may be drawn out of the steam treatment tank 1 via the pipe 9.

In the steam drying method of the present invention, as shown in FIGS. 1 and 2, moisture-containing steam is extracted from the inside of the steam treatment tank 1 via a pipe 22 while performing the above-described steam drying, and the steam compressor 20 is used. Pressurized steam, and the pressurized steam is
Via a gas separation membrane module 30 having a built-in gas separation membrane for selectively allowing moisture to pass therethrough, and in the gas separation membrane module 30, the permeate side of the gas separation membrane was sufficiently depressurized by a vacuum pump 40. In the state, the vapor is brought into contact with the gas separation membrane on the supply side of the gas separation membrane, and the permeated vapor “steam containing a large amount of water” is discharged from the permeation side of the gas separation membrane through the extraction pipe 32 and The unremoved vapor from which moisture has been removed from the supply side of the gas separation membrane, the dried permeate vapor “dry lower alcohol vapor” is taken out via the extraction pipe 31, and finally, the dried lower alcohol vapor is taken out via the extraction pipe 31. The material to be dried 4 in the steam processing tank 1 is sprayed through the pipe 35 and the nozzle 36 to be reused for steam drying.

The gas separation membrane described above has a sufficiently high “permeation rate (PH ₂ O)” of water vapor (H ₂ O) of 1.0 × 10 ⁻⁴ cm ³ (STP) / cm ² · sec · cmHg or more. , Which indicates the gas separation performance that water vapor can be selectively permeated from a mixed vapor of water (H ₂ O) and lower alcohol (ROH) [The separation degree (PH ₂ O / PROH) is about 100 to 10,000] , Especially 500-8000
And the operating temperature of the film is 50 ~ 300 ℃
The temperature is preferably in a wide temperature range (especially a high temperature of 80 to 250 ° C.). For example, an asymmetric gas separation membrane (particularly an asymmetric gas separation hollow) made of a heat-resistant polymer such as aromatic polyimide, aromatic polyamide, and polysulfone. Thread membrane) is preferred.

In the steam drying method of the present invention, the above-described steam compressor 20 is used.
When supplying pressurized steam pressurized in the gas separation membrane module 30, the pressurized steam is at a high temperature (preferably 60 to
250 ° C., especially 80-200 ° C.), and the pressure of the pressurized steam is 0.1-10 kg / cm ² G,
Preferably, it is about 0.2 to 5 kg / cm ² G.

Further, it is preferable that the pressure on the permeation side of the gas separation membrane of the gas separation membrane module 30 is reduced to 500 torr or less, particularly 200 torr or less.

In the steam drying method of the present invention, unpermeated steam (dry lower alcohol vapor from which moisture has been removed) of the gas separation membrane module 30 is sprayed on the material 4 to be dried in the steam treatment tank 1. The temperature of the alcohol vapor is preferably equal to or higher than the boiling point of the lower alcohol, and when the lower alcohol is isopropanol, the temperature is preferably 82 to 90 ° C.

Further, the permeated vapor (vapor containing a high percentage of moisture) of the gas separation membrane module 30 may be cooled by the cooler 33, extracted from the trap 34, and discharged out of the system.

In the steam drying method of the present invention, new lower alcohol is replenished from the lower alcohol tank 50 to the bottom (liquid reservoir 2) of the steam treatment tank 1 via the pipe 51 and the pump 52 at a temperature of about 0 to 50 ° C. Preferably it is supplied. The new lower alcohol to be replenished has a water content of 2% by weight or less,
In particular, it is preferably a low-alcohol liquid having a high purity of 1% by weight or less (particularly 98% by weight or more).

The lower alcohol used in the steam drying method of the present invention has 2 to 2 carbon atoms such as ethanol, n-propanol, isopropanol, n-butanol and isobutanol.
Preferred are lower alcohols having four, of which isopropanol is most preferred.

The apparatus for steam drying of the present invention generally comprises (a) a steam treatment tank 1, (b) a steam compressor 20, (c) a gas separation membrane module 30, and, as shown in FIG. 1 and FIG. ,
(D) A steam drying apparatus having a pipe 35 for supplying a lower alcohol vapor to the steam processing tank 1 and a nozzle 36.

For example, as shown in FIG. 1, the steam processing tank 1 is provided with a means for arranging a holder 6 that can hold the object 4 to be dried and move it above the collection unit 5. In addition, a liquid reservoir 2 and a heater 3 on the outer side thereof, a pipe 35 and a nozzle 36 for supplying and spraying a dry lower alcohol vapor are provided, and a cooling pipe 7 is provided on a side wall. Further, it is preferable to have a pipe 8 for taking out the liquid from the liquid reservoir, and as shown in FIG. 2, the vapor processing tank 1 in FIG. It is preferable to have a collecting part 5 and a pipe 9 for taking out the condensate from the collecting part 5.

The above-mentioned steam compressor 20 preferably has a pressure regulating valve 21.

The gas separation membrane module 30 is for gas separation and removal of water vapor from the steam, and incorporates the above-described gas separation membrane (such as a hollow fiber membrane). From the gas separation membrane, and if necessary, connected to a vacuum pump 40 for reducing the permeate side of the gas separation membrane to a reduced pressure state. A pipe 32, a cooler 33 for cooling the permeated steam, and a trap 34 for the coolant are provided so that the coolant of the permeated steam containing a high percentage of water can be discharged. Is also good.

INDUSTRIAL APPLICABILITY The steam drying method and apparatus of the present invention can be effectively applied to, for example, drying of electronic materials such as printed wiring boards, semiconductor wafers, precision electronic components, liquid crystal substrates, and lenses after washing with water.

〔Example〕

Hereinafter, the present invention will be described in more detail by way of examples.

Example 1 A steam drying apparatus having a flow as shown in FIG. 1 was used, and a gas separation hollow fiber membrane made of aromatic polyimide manufactured by Ube Industries, Ltd. (trade name: UBE polyimide) was used as a gas separation membrane module. Using a gas separation membrane module (membrane area: 2.79 m ² ) with a built-in membrane (type D), a lens (diameter: 40 mm, approximately 6
(10,000 sheets) were continuously steam-dried for about one week with steam of a treatment solution of isopropanol (IPA).

Table 1 shows the pressures and temperatures of the respective fluids at the points (1) to (3) shown in the flow of FIG. 1 and the average values of the compositions and the flow rates of those fluids.

Example 2 A steam drying apparatus having a flow as shown in FIG. 2 was used, and a gas separation hollow fiber membrane made of aromatic polyimide manufactured by Ube Industries, Ltd. (trade name: UBE polyimide) was used as a gas separation membrane module. Using a gas separation membrane module (membrane area: 1.0 m ² ) with a built-in membrane (type D), for a lens (diameter: 40 mm, about 60,000 pieces) that is sufficiently wet as a material to be dried, Steam drying was performed continuously for about one week with steam of a treatment liquid of isopropanol (IPA).

Table 2 shows the pressures and temperatures of the respective fluids at the points (1) to (3) shown in the flow of FIG. 2 and the average values of the compositions and the flow rates of those fluids.

As a result of each of the above embodiments, the wet lens or semiconductor wafer in the steam processing tank has been substantially free of attached water, has been sufficiently dried, and has a liquid at the bottom of the steam processing tank. The isopropanol in the reservoir is
There was substantially no increase in the water concentration, and the isopropanol concentration was stably maintained at 97.0% by weight or more.

(Operation and effect of the present invention)

According to the steam drying method and the apparatus of the present invention, in the steam drying of the object to be dried with high precision, the wet lens,
It is possible to stably and continuously perform low-energy, low-cost, stable, and long-term steam drying operations on objects to be dried such as semiconductor wafers and wiring boards.

Further, the concentration of the processing liquid in the liquid storage section of the steam processing tank can be stably maintained at a high level for a long time.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are flowcharts each schematically showing an example of an apparatus for carrying out the present invention. 1; steam treatment tank, 20; steam compressor, 30; gas separation membrane module, 33; cooler, 34; trap, 35; piping, 36; nozzle,
40; vacuum pump.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yu Umeda 4-2-16-1 Nihonbashi Muromachi, Chuo-ku, Tokyo Headquarters of Watanabe Shoko Co., Ltd. (72) Inventor Motosuro Yamaya 4-2-2 Nihonbashi Muromachi, Chuo-ku, Tokyo No. 16 Watanabe Shogyo Co., Ltd. (56) References JP-A-62-106630 (JP, A) JP-A-1-155928 (JP, A) JP-A-63-182818 (JP, A) JP-A-62 -260324 (JP, A)

Claims (2)

(57) [Claims] (A) A wet object to be dried is placed inside a steam treatment tank having a lower alcohol reservoir at the bottom, and a lower alcohol vapor generated from the reservoir is provided. The non-permeated steam described below is brought into contact with the object to be dried, and the object to be dried is steam-dried. (B) The water-containing steam in the steam treatment tank is extracted, and 0.1 to 10 kg / cm ² G by a steam compressor. Then, the pressurized steam is supplied to the gas separation membrane module. (C) In the gas separation membrane module, the mixed pressurized steam is brought into contact with the gas separation membrane, and A vapor drying method, comprising discharging permeated vapor and extracting dried non-permeated vapor from a supply side of the gas separation membrane; and (D) spraying the non-permeated vapor onto a material to be dried in the steam treatment tank. . (A) a steam treatment tank having a lower alcohol reservoir at the bottom thereof; (b) a steam compressor for pressurizing moisture-containing steam extracted from the steam treatment tank; A) a gas separation membrane module for gas separation and removal of water from the pressurized steam; (d) a pipe for supplying the dried non-permeated steam taken out of the gas separation membrane module into a steam treatment tank, and a tip of the pipe. A steam drying apparatus comprising a nozzle for spraying an object to be dried provided in the apparatus.