KR20100081480A - Air conditioning system of clean room for producing iodine-type polarizing film - Google Patents

Abstract

PURPOSE: An air conditioning system of a clean room for producing an iodine type Polaroid film is provided to make the environment of a clean room clean and safe by lowering the concentration of iodine. CONSTITUTION: An air conditioning system of a clean room for producing an iodine type Polaroid film comprises an air conditioner, an air inlet, a circulating gas discharging part, and an iodine filtering unit(100). The air conditioner is installed the outside a clean room and circulates gas in the clean room. The circulating gas discharging part discharges a part of circulating gas to air. The iodine filtering unit is installed inside the air conditioner and eliminates iodine from the circulating gas.

Description

Air Conditioning System of Clean Room for Producing Iodine―type Polarizing Film}

The present invention relates to an air conditioning system of a clean room for producing a polarizing film, and more particularly, in an air conditioning system of a clean room for producing an iodine type polarizing film including a dye bath, a drawing bath and a water bath. An air conditioner installed outside the clean room for circulating gas in the room; An air inlet for introducing external air onto the circulating gas flow path directed to the clean room; A circulating gas discharge part for discharging some circulating gas into the atmosphere on a circulating gas flow path from the clean room to an air conditioner; And an iodine filtering device installed on a circulating gas flow path to remove iodine in the circulating gas, wherein the air circulation from the outside and the discharge of some circulating gas are performed, thereby circulating gas and circulating gas in a clean room. An air conditioning system, characterized in that the removal of iodine from

Polarizing sheet (Polarizing Sheet) or polarizing film (Polarizing Film) generally has a function to convert the natural light into polarized light, this polarizing function is implemented by a material that is dyed to the polarizing plate. Generally, the iodine type polarizing film in which iodine was salted is used as a polarizing material for a liquid crystal display.

The iodine type polarizing film is manufactured by dyeing a polyvinyl alcohol (PVA) -based film using dichroic iodine or a dichroic dye and orientating it in a fixed direction by a method such as uniaxial stretching. do. For example, the unstretched PVA film is uniaxially stretched in an aqueous solution and then immersed in a solution containing iodine and potassium iodide, or the unstretched PVA film is immersed in a solution containing iodine and potassium iodide and then uniaxially stretched. Alternatively, the unstretched PVA film is uniaxially stretched in a solution containing iodine and potassium iodide, or the unstretched PVA film is uniaxially stretched in a dry state and then immersed in a solution containing iodine and potassium iodide to prepare a polarizing film. .

The PVA film having iodine adsorbed and oriented is post-treated by a method such as water washing or drying to obtain a polarizing film, and a polarizing plate is obtained by laminating a protective film on at least one side of the obtained polarizing film.

The manufacturing process of the polarizing plate as described above is performed in a clean room, in which a temperature and humidity are controlled and a space controlled to maintain a harmful gas in the air below a predetermined range. In the case of the polarizing plate, it is necessary to maintain the temperature and humidity of the manufacturing site at a constant level, and to keep harmful gases contained in the air at a predetermined range or less, so that product defects do not occur in the manufacturing process, and thus a good quality product can be produced. .

On the other hand, since the iodine dyed in the PVA film is relatively high at a normal temperature (25 ° C.) as about 0.31 mmHg, the iodine is easily sublimed into the air of a clean room for producing a polarizing plate. The sublimed iodine is present in air above a certain concentration and diffuses through the air conditioning system throughout the clean room to produce the polarizer.

According to the Journal of Nuclear Materials 265 (1999) 161-177, iodine is reactive with iron, as shown in the following equation, to corrode various instruments and devices made of stainless steel.

Fe + I ₂ → FeI ₂

FeI ₂ + y / 2O ₂ → FeI _x O _y + (1-x / 2) I ₂

In addition, when the concentration of iodine in the air in the clean room exceeds the allowable concentration, it is harmful to the human body, especially when prolonged exposure may cause serious damage to the human body. Therefore, in order to prevent corrosion of the apparatus used for a polarizing plate manufacturing process and to ensure the environmental stability of a polarizing plate manufacturing process, it is necessary to remove iodine contained in the air in a clean room.

The use of adsorbents as a method for removing iodine contained in air or gas phase has been used in the field for removing radioactive iodine in nuclear power plants. For example, the invention relates to an iodine adsorbent using activated carbon or zeolite carrying silver or an amine compound, and an iodine adsorbent using zeolite which can be used at high temperatures. Specifically, U.S. Patent No. 3,658,467 proposes X-type zeolite or mordenite loaded with silver, and U.S. Patent No. 4,036,940 suggests alumina impregnated with copper and chromium. Proposed. In addition, US Pat. No. 4,312,647 proposes a carrier in which silver sulfate or silver sulfite is deposited as a film as a radioactive iodine adsorbent, and US Pat. No. 4,735,786 supports silver. Pentasil zeolite has been proposed.

As such, although many technologies for removing radioactive iodine generated in a nuclear power plant have been developed, no effective iodine removal method or system has been developed in the polarizer field in consideration of manufacturing process characteristics in the art.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

The inventors of the present application, through in-depth study, polarized by a specific configuration of air conditioning system which performs iodine removal from the circulating gas together with the gas circulation to the clean room while the inflow of air from the outside and the discharge of some circulating gas are made. The inventors of the present invention have found that the iodine generated in the polarizing plate manufacturing process can be efficiently and safely removed while improving the efficiency of the film manufacturing process.

Accordingly, the air conditioning system according to the present invention is an air conditioning system of a clean room for manufacturing an iodine type polarizing film including a dye bath, a stretching bath and a water cutting bath, and an air conditioner installed outside the clean room to circulate gas in the clean room. ; An air inlet for introducing external air onto the circulating gas flow path directed to the clean room; A circulating gas discharge part for discharging some circulating gas into the atmosphere on a circulating gas flow path from the clean room to an air conditioner; And an iodine filtering device installed on a circulating gas flow path to remove iodine in the circulating gas, wherein the air circulation from the outside and the discharge of some circulating gas are performed, thereby circulating gas and circulating gas in a clean room. It consists of performing iodine removal from.

That is, the air conditioning system of the clean room for manufacturing the iodine type polarizing film according to the present invention, according to the specific configuration as described above, while the inflow of air from the outside and the discharge of some circulating gas and the gas circulation for the clean room and By removing iodine from the circulating gas, by effectively removing iodine while improving the efficiency of the polarizing film manufacturing process, it is possible to minimize the occurrence of product defects and to extend the life of the device.

As described above, the preparation of the iodine type polarizing film is performed in a clean room, which includes a dye bath, a drawing bath and a water bath. A process of dyeing iodine on the PVA film used as a substrate of the polarizing film in the dyeing bath is performed, a process of stretching the iodine-dyed PVA film in the drawing tank is performed, the PVA stretched in the water tank The process of washing and drying the film is carried out.

In the air conditioning system of the present invention, the air inlet may be an external air conditioner connected to an air conditioner to introduce external air into the air conditioner as a member for introducing external air onto the circulating gas flow path to the clean room.

The air conditioner connected to the air inlet unit is installed outside the clean room to circulate the gas in the clean room, and purifies a certain amount of outside air through the air inlet unit to enter the system.

The circulating gas discharge part may be a member for discharging a portion of the circulating gas into the atmosphere on the circulating gas flow path from the clean room toward the air conditioner, and may include a fan or blower that sucks the circulating gas and discharges it into the atmosphere.

In addition, the circulating gas discharge unit may have a structure that further includes an iodine absorbing device for absorbing and removing iodine in order to prevent iodine from being discharged to the outside atmosphere even in a small amount.

Such an iodine absorber may be, for example, an iodine absorbing tower or an iodine absorbing tank.

The iodine absorption tower or the iodine absorption tank removes iodine remaining in the circulation gas by bubbling the circulation gas in the iodine absorption solution. The bubbling may be bottom bubbling or top bubbling, and the bubbling may be performed by supplying a gas to the liquid to increase the contact area between the molecules constituting the liquid and the gas molecules. Do. Therefore, iodine present in the circulating gas can be effectively removed by bubbling the iodine absorbing solution.

When the circulating gas discharge unit further includes an iodine absorbing device, the iodine absorbing device may be installed in front of the fan or blower of the circulating gas discharge unit or may be installed at the rear.

The iodine absorbing solution used in the iodine absorbing device is not particularly limited as long as it is a liquid substance containing a substance capable of absorbing iodine. For example, in view of ease of handling and economical efficiency of the compound, sodium hydroxide, hydroxide An aqueous solution composed of at least one selected from the group consisting of potassium, sodium carbonate, potassium carbonate, calcium hydroxide and barium hydroxide can be used, and in particular, an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution can be preferably used.

As a result, the circulating gas containing iodine may be bubbled in an aqueous solution of sodium hydroxide solution or potassium hydroxide, and then removed in the form of an iodine salt such as sodium iodide or potassium iodide through a reaction.

The amount of external air introduced into the air conditioning system through the air inlet and the amount of air discharged into the atmosphere through the circulating gas outlet may be determined by various factors such as the size of the air conditioning system, the density of the circulating gas, and the density of the containing material. It is preferable that it is 5 to 30% of the amount of circulating gas.

The flow rate of the circulating gas is preferably 0.1 to 1 m / s. If the flow rate of the circulating gas is too slow, the iodine concentration in the air conditioning system may be high, which may cause product defects and corrosion of the device. A high flow rate of is not desirable, because the increase in energy for circulation can greatly increase, leading to an increase in the cost of the product.

The iodine filtering device is not particularly limited as long as it is on a circulating gas flow path, and may be preferably installed inside the air conditioner. In some cases, it can be installed together in any position on the inside of the air conditioner and other circulation gas flow path.

Preferred examples of such iodine filtering device,

(a) a pre-filter for removing foreign matter from the incoming gas;

(b) an iodine adsorption filter for selectively adsorbing and removing iodine from the gas passing through the prefilter;

(c) a medium filter for removing fine particles in the gas passing through the iodine adsorption filter; And

(d) an iodine sampler that collects gases for analysis of iodine content;

The structure containing the can be mentioned.

Such iodine filtering devices are themselves new in the art.

The differential pressure applied to the iodine filtering device is preferably 15 to 30 mmAq.

The pre-filter and the medium filter are physical filters for removing foreign matters or fine particles in the inlet gas. The pre-filter is composed of relatively large pores, and the medium filter is composed of relatively small pores.

The iodine filtering device as described above has the advantage of reducing the operating cost of the iodine filtering device by reducing the replacement cycle of the entire filter by replacing the pre-filter, which is relatively inexpensive and has large pores, with a relatively high frequency. Specifically, the pre-filter is installed in front of the medium filter, the dust having a large particle size is filtered by the pre-filter can further extend the replacement cycle of the medium filter.

The material of the prefilter and the medium filter is not particularly limited as long as the material has a plurality of pores through which gas can penetrate within a condition range as defined above, and may be, for example, in the form of a nonwoven fabric.

The iodine adsorption filter mounted between the prefilter and the medium filter contains an iodine adsorbent to selectively adsorb and remove iodine.

Examples of the iodine adsorbent include activated carbon, activated carbon fiber, zeolite, silica (SiO ₂ ), titania (TiO ₂ ), alumina (Al ₂ O ₃ ), and the like. Can be used. Zeolite may be specifically X-type zeolite (X-type zeolite), mordenite (mordenite), pentasil zeolite (pentasil zeolite) and the like can be used. When the adsorbent is loaded with at least one member selected from the group consisting of amine, silver, silver sulfate, silver sulfite, silver nitrate, It is more preferable for increasing iodine adsorption removal performance. However, the adsorbent, the supported component, and the like are not limited to the above illustrated materials.

The iodine sampler may be installed, for example, in front of and / or behind the iodine adsorption filter, and in one preferred example, a sampling valve installed near the prefilter or media filter, which collects the detection gas from the sampling valve. And an iodine sampling vacuum pump for inhaling gas into the sampling valve.

Preferably, the iodine sampler may be installed in front of the prefilter and behind the medium filter, respectively, so that the iodine in the circulating gas is collected through the iodine sampler before and after passing through the iodine filtering device, and then their concentrations. By measuring by an analytical method such as ion chromatography (ion chromatography) can be confirmed the amount of iodine removal through the iodine filtering device. Based on this, it is possible to determine the process control of the system as a whole, whether to replace the parts of the filtering device.

In one preferred example, the gas of the dye bath may be a structure including a local gas outlet for exiting to the atmosphere in a state isolated from the rest of the clean room.

As a result of measuring the iodine concentration contained in the air near the salt bath, the stretching bath and the water tank in the clean room, as shown in Table 1 below, the concentration of iodine shows the maximum at the outlet of the salt bath.

TABLE 1

The relative iodine concentration is a value obtained by dividing the iodine concentration at the iodine sampling position by the iodine concentration at the inlet of the salt bath. Therefore, the local isolation of the dye bath with the highest iodine concentration and the local discharge of the air from the dye bath can lower the iodine concentration circulated through the air conditioning system and reduce the load of the iodine filtering device installed in the air conditioning system. There is this.

Preferably, the iodine absorber may be further installed at the local gas outlet. The iodine absorber is as mentioned above.

As another preferred example, if a salt bath is locally isolated inside the clean room and there is still a process zone with a high iodine concentration in the clean room, even if the air of the salt bath is discharged locally, an iodine filter is present in that area. An air purifier equipped with an additional can be installed. An air purifier equipped with an iodine filter has the advantage of lowering the iodine concentration in a process zone with a high iodine concentration to maintain a more comfortable and safe environment in a clean room, and reduce the load of an iodine removal device installed in an air conditioning system.

Hereinafter, the present invention will be further described with reference to the drawings and the like, but the scope of the present invention is not limited thereto.

1 schematically shows an iodine filtering device according to an embodiment of the present invention.

Referring to FIG. 1, the iodine filtering device 100 according to the present invention selectively adsorbs and removes iodine from a gas passing through the prefilter 210 and the prefilter 210 to remove foreign substances from an inflowing gas. The iodine adsorption filter 220, the medium filter 230 for removing fine particles in the gas passing through the iodine adsorption filter 220, and the iodine sampler 300 for collecting the gas.

The iodine filtering device 100 is installed in the air conditioning pipe 110 of the air conditioning system, for example, to remove iodine in the circulating gas. Therefore, the circulating gas introduced through the air conditioning tube 110 is removed with foreign particles having large particles while passing through the pre-filter 210 for removing the foreign substances, and the iodine present in the circulating gas through the iodine adsorption filter 220. Is selectively adsorbed and removed. The iodine adsorption filter 220 includes an iodine adsorbent and can selectively adsorb only iodine in the circulating gas. As the circulating gas passing through the iodine adsorption filter 220 passes through the medium filter 230, fine particles such as dust present in the circulating gas are removed. Therefore, it is possible to satisfy the conditions of the clean room where all foreign substances such as dust contained in the air required in the polarizing film production process are removed.

The iodine filtering device 100 is provided with an iodine sampler 300 for collecting the gas to analyze the concentration of iodine. The iodine sampler 300 is provided with a sampling valve 310 that can be adjusted to pass a portion of the circulating gas, and when the sampling valve 310 is opened and the iodine sampling vacuum pump 330 is operated, the detection gas is collected. The circulating gas is introduced into the iodine sampling detector 320. The iodine sampler 300 is installed at each of the previous part and the subsequent part of the iodine adsorption filter 220 to collect gases therefrom, and thus the concentration of iodine and the iodine filtering device 100 from the collected gas. The amount of iodine removed through can be measured.

2 to 4 schematically illustrate the configuration of air conditioning systems of a clean room for manufacturing an iodine type polarizing film according to various embodiments of the present disclosure.

First, referring to FIG. 2, a clean room 10 in which a manufacturing process of a polarizing film is performed includes a dye bath 11, a stretching bath 12, and a water cut bath 13, and an air conditioning system 200. Air is circulated.

The air conditioning system 200 includes an external air conditioner 22 for introducing external air, an air conditioner 21 for circulating air introduced from the external air conditioner 22, and some circulating gas into the clean room 10, and the clean room 10. A discharge section 23 comprising a fan or blower for discharging some of the circulating gas on the circulating gas flow path from the air to the air conditioner 21, to remove iodine in the air and some circulating gas introduced from the outside It is composed of an iodine filtering device 100 installed in the air conditioner (21).

The air in the atmosphere is introduced into the air conditioner 21 installed outside the clean room 10 through the external air conditioner 22 to circulate the gas in the clean room 10.

Iodine contained in the circulating gas is removed from the iodine filtering device 100 installed in the air conditioner 21.

Some circulating gas is discharged to the outside through the discharge unit 23, the other is circulated back to the clean room 10 through the air conditioner (21).

An iodine absorber (not shown) may be additionally installed in the discharge portion 23 of the circulating gas, and the iodine absorbing device may be an iodine absorbing tower or an iodine absorbing tank, and the circulating gas may be an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution. It is bubbled into the iodine absorption solution of iodine is removed.

In the air conditioning system 201 of FIG. 3, the dyeing tank 12 having the highest concentration of iodine is locally isolated in the clean room 10, and a local gas for locally discharging the air of the dyeing tank 12. The discharge part 24 is characterized in that it is installed in the air conditioning system of the clean room 10.

The local gas discharge part 24 may be further provided with an iodine absorber (not shown) such as an iodine absorption tower or an iodine absorbing tank, as in the discharge part 23 of the circulating gas. The iodine can be removed more effectively by locally isolating the dye bath 12 having the highest concentration of iodine in the c) and performing intensive iodine removal.

The air conditioning system 202 of FIG. 4 is characterized in that, when there is a process zone having a high iodine concentration in the clean room 10, an air cleaner 30 equipped with an iodine filter is installed in the zone. to be. The air purifier 30 equipped with the iodine filter can keep the environment in the clean room more pleasant and safe by lowering the iodine concentration in the process zone having a high iodine concentration, and loads such as an apparatus for removing iodine from the air conditioning system 202. Can be reduced.

In the air conditioning system 201 of FIG. 3 and the air conditioning system 202 of FIG. 4, other configurations, gas circulation, and discharge are the same as those of the air conditioning system 200 of FIG. 2, and thus description thereof is omitted.

In Example 1 below, in order to evaluate the performance of the iodine filtering device according to the present invention, after collecting the iodine in the air passing through the filter unit using an iodine sampler, the concentration was measured by chromatography.

Example 1

An iodine filtering device composed of a pre-filter, an iodine adsorption filter, a medium filter, and an iodine sampler capable of collecting iodine contained in air, was installed inside the air conditioner in the air conditioning system as shown in FIG. The air flow rate of the air conditioning system equipped with the iodine filtering device was 10,000 m ³ / hr (0.5 m / s based on the flow rate), the temperature was adjusted to 20 ° C., and the humidity of the air was 60%. In addition, the differential pressures applied to the prefilter, the iodine adsorption filter, and the medium filter were 5 mmAq, 9 mmAq, and 13 mmAq, respectively.

In order to evaluate the performance of the apparatus, iodine in the air passing through the apparatus was taken three times at intervals of 14 to 60 days using an iodine sampler, and the concentration of iodine was measured using ion chromatography.

In addition, the iodine removal rate was defined as follows, and the iodine removal rate according to the iodine adsorption filter operation days was specified. The results are shown in Table 2 and FIG. 5.

Iodine Removal Rate (%) = (Cin-Cout) / Cin × 100

Where Cin is the iodine concentration at the adsorbent inlet,

Cout is the iodine concentration at the adsorbent outlet.

TABLE 2

As shown in Table 2 and FIG. 5, the iodine concentration in the air passing through the iodine adsorption filter was reduced by about 94 to 98%, and the iodine removal efficiency was not reduced even after the air conditioning system was operated for a long time. Removal rate was maintained. This demonstrates not only good iodine removal effect but also long-term maintenance in the system and apparatus according to the present invention.

As described above, the air conditioning system of the clean room for manufacturing the iodine type polarizing film according to the present invention is the circulating gas and the iodine from the gas circulation to the clean room while the inflow of air from the outside and the discharge of some circulating gas By eliminating efficiencies of iodine while improving the efficiency of the polarizing film manufacturing process, it is possible to minimize the occurrence of product defects and to prolong the life of devices and the like. In particular, by further including an air cleaner equipped with a local gas outlet and an iodine filter, iodine removal efficiency can be greatly improved.

Those skilled in the art to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above contents.

1 is a schematic configuration diagram of an iodine filtering device according to an embodiment of the present invention;

2 to 4 are schematic configuration diagrams of air conditioning systems of a clean room for manufacturing an iodine type polarizing film according to embodiments of the present invention;

5 is a graph showing iodine removal efficiency in an embodiment of the present invention.

Claims (18)

An air conditioning system of a clean room for producing an iodine type polarizing film including a dyeing bath, a drawing bath, and a cutting bath, An air conditioner installed outside the clean room for circulating gas in the clean room; An air inlet for introducing external air onto the circulating gas flow path directed to the clean room; A circulating gas discharge part for discharging some circulating gas into the atmosphere on a circulating gas flow path from the clean room to an air conditioner; And An iodine filtering device installed inside an air conditioner to remove iodine in the circulating gas; The air conditioning system comprising a gas circulation for the clean room and iodine removal from the circulating gas while the air inflow from the outside and the discharge of some circulating gas are made. The air conditioning system according to claim 1, wherein the air inlet is an external air conditioner connected to the air conditioner to introduce atmospheric air into the air conditioner. The air conditioning system according to claim 1, wherein the circulating gas discharge part includes a fan or a blower which sucks the circulating gas and discharges it to the atmosphere. The air conditioning system of claim 1, wherein the circulating gas discharge part further comprises an iodine absorber. The air conditioning system according to claim 1, wherein the iodine absorbing device is an iodine absorbing tower or an iodine absorbing tank. 6. The air conditioning system according to claim 5, wherein the iodine absorber comprises an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution. The air conditioning system according to claim 1, wherein the amount of external air introduced through the air inlet and the amount of air discharged into the atmosphere through the circulating gas outlet are 5 to 30% of the amount of circulating gas per second, respectively. The air conditioning system according to claim 1, wherein the circulating gas flow rate is 0.1 to 1 m / s. The air conditioning system according to claim 1, wherein the iodine filtering device is installed on a circulating gas flow path between the clean room or the circulating gas discharge part. The air conditioning system according to claim 1, wherein the gas of the dye bath includes a local gas outlet for exhausting to the atmosphere in isolation from the rest of the clean room. 11. An air conditioning system according to claim 10, wherein said local gas outlet is provided with an iodine filtering device and / or an iodine absorber. The air conditioning system according to claim 1, wherein an air purifier equipped with an iodine filter is further installed in the clean room. An iodine filtering device used in an air conditioning system of a clean room for manufacturing an iodine type polarizing film, (a) a pre-filter for removing foreign matter from the incoming gas; (b) an iodine adsorption filter for selectively adsorbing and removing iodine from the gas passing through the prefilter; (c) a medium filter for removing fine particles in the gas passing through the iodine adsorption filter; And (d) an iodine sampler that collects gases for analysis of iodine content; Iodine filtering device comprising a. The iodine filtering device of claim 13, wherein the differential pressure applied to the iodine filtering device is 15 to 30 mmAq. The method of claim 13, wherein the iodine adsorption filter is activated carbon, activated carbon fiber, X-type zeolite, mordenite, pentasil zeolite, An iodine filtering device comprising at least one iodine adsorbent selected from the group consisting of silica (SiO ₂ ), titania (TiO ₂ ) and alumina (Al ₂ O ₃ ). The iodine adsorption filter according to claim 13, wherein the iodine adsorption filter comprises at least one carrier selected from the group consisting of activated carbon, activated carbon fiber, X-type zeolite, mordenite, pentasil zeolite, silica, titania and alumina. Iodine filtering, characterized in that it comprises an iodine adsorbent carrying at least one member selected from the group consisting of silver, silver sulfate, silver sulfite and silver nitrate. Device. The iodine filtering device according to claim 13, wherein the iodine sampler is provided at the front of the prefilter and the rear of the medium filter, respectively. 18. The iodine sampling device according to claim 17, wherein the iodine sampler is a sampling valve installed near a prefilter or a media filter, an iodine sampling detector for collecting detection gas from the sampling valve, and an iodine sampling vacuum pump for inhaling gas into the sampling valve. An iodine filtering device, characterized in that configured to include.

Images