JP2006192388A - Gas adsorbing filter medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas adsorbing filter medium having excellent removal performance of poisonous gas in the air, less re-releasing of trace out-gas or the like, and flame retardancy. <P>SOLUTION: The gas adsorbing filter medium supports a humectant such as lithium bromide, which absorbs moisture in the air and holds it on the surface of a substrate, on the surface of the substrate such as polypropylene. With the water retention performance, which makes water-soluble (polar) gas to be easily drawn and held, the filter medium supports an adsorbent such as zinc sulfate, calcium carbonate, or iodine for adsorbing a predetermined gas such as an acidic gas or a basic gas. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gas adsorption filter medium.

Conventionally, a gas adsorption filter has been devised in which an adsorbent such as phosphoric acid or calcium carbonate is added to a filter base material containing activated carbon or zeolite to adsorb acid gas or basic gas. When this type of gas adsorption filter is applied to building equipment such as a clean room, flame retardancy is required. Therefore, in order to impart flame retardancy to the filter, a hardly soluble flame retardant (for example, a phosphorus flame retardant such as aluminum metaphosphate, melamine phosphate, magnesium phosphate, condensed phosphate amide, aluminum hydroxide, water) It has been proposed to add an inorganic flame retardant such as magnesium oxide (for example, see Patent Document 1).
JP 2002-079083 A

  However, since the porous materials such as activated carbon and zeolite described above mainly consist of fine pores and have a large specific surface area and physically adsorb the gas to be adsorbed, fluctuations in the upstream concentration and temperature fluctuations of the gas to be adsorbed As a result, the adsorbed gas is re-released, and so-called outgas is generated.

  Therefore, in view of the above problems, an object of the present invention is to provide a gas-adsorbing filter medium that has little re-emission of a minute amount of outgas, etc., has flame retardancy, and is excellent in the performance of removing harmful gases in the air. is there.

  In order to achieve this object, the characteristic configuration of the gas-adsorbing filter medium according to the present invention is that, as described in claim 1, an adsorbent that adsorbs a predetermined gas and moisture in the air are absorbed on the substrate surface. And a moisturizing agent that retains moisture on the surface of the substrate.

In the above feature configuration, as described in claim 2, the humectant is lithium bromide (Li ₂ Br), lithium chloride (LiCl), lithium hydroxide (LiOH), lithium nitrate (LiNO ₃ ), It preferably contains at least one component selected from the group consisting of lithium chlorate (LiClO ₃ .1 / 2H ₂ O) and lithium perchlorate (LiClO ₄ ),
The adsorbent is selected from the group consisting of zinc sulfate (ZnSO ₄ ), zinc nitrate (Zn (NO ₃ ) ₂ .6H ₂ O) and zinc iodide (ZnI ₂ ). Preferably at least one acidic substance,
As described in claim 4, the adsorbent is calcium carbonate (CaCO ₃ ), potassium carbonate (K ₂ CO ₃ ), sodium carbonate (Na ₂ (CO ₃ )), potassium hydroxide (KOH) water. Selected from the group consisting of calcium oxide (Ca (OH) ₂ ), sodium hydroxide (NaOH), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), aluminum nitrate (Al (NO ₃ ) ₃ ), and hydrates thereof Preferably at least one basic substance,
As described in claim 5, the adsorbent is iodine (I ₂ ), potassium iodide (KI), calcium iodide (CaI ₂ ), sodium iodide (NaI), potassium iodate (KIO _3). ), At least one reducing agent selected from the group consisting of calcium iodate (Ca (IO ₃ ) ₂ ) and sodium iodate (NaIO ₃ ),
As described in claim 6, the support containing the adsorbent and the humectant is supported at a ratio of more than 5 wt% and not more than 300 wt% with respect to the weight of the base material. Preferably
As described in claim 7, it is preferable that the support containing the adsorbent and the humectant is supported on the surface of the base material at a rate of 1 to 600 g / m ² .
As described in claim 8, the base material is polypropylene, polyacetal, polyarylate, polyamide, polyimide, polycarbonate, polyethylene, polyester, polyethylene terephthalate, polyether ether ketone, polyether sulfone, polyphenylene sulfide, carbon. It is preferably at least one substance selected from the group consisting of fiber, silicon carbide, phenol resin, glass, silica / alumina, liquid crystal polymer, natural cellulose, rock wool, wool, cotton, hemp and silk,

  Moreover, the characteristic configuration of the gas adsorption filter of the present invention to achieve this object is that, as described in claim 9, the gas adsorption filter medium according to any one of claims 1 to 8 is formed into a predetermined shape. It is in the point which was formed into.

  In the above characteristic configuration, as described in claim 10, the shape of the base material is preferably a paper shape, a honeycomb shape, a mini-pleat shape, a felt shape, or a finely packed shape.

  Further, the characteristic configuration of the fan / filter composite unit of the present invention for achieving this object is as described in claim 11, and the gas adsorption filter medium according to any one of claims 9 or 10, It is in the point provided with the ventilation means and the dust removal filter.

  According to the first aspect of the present invention, when the gas adsorption filter medium is constructed, the adsorption of the gas is carried out by supporting an adsorbent that adsorbs a predetermined gas on the surface of the substrate according to the type of gas to be removed. Removal is performed. Here, when a moisture retaining agent that absorbs moisture in the air and retains moisture on the substrate surface is supported on the substrate surface, a region containing a large amount of moisture is formed on the substrate surface due to the water retention effect. The The presence of this region makes it easier for water-soluble (polar) gas to be attracted and stagnant, thereby improving the adsorption removal performance of this type of gas. In addition, since a sufficient amount of water-soluble (polar) adsorbent can be held in this region, the amount of gas chemical adsorption can be further increased. These effects will be particularly effective when the gas to be removed is present at a low concentration and contact with the adsorbent is unlikely to occur. Furthermore, since the gas removal can be performed mainly by chemical adsorption, there is no outgassing as in the case of physical adsorption using a conventional porous body. Moreover, a flame retardance is provided to a filter medium by forming the area | region which contains much moisture on the base-material surface.

As described in claim 2, the humectant is lithium bromide (Li ₂ Br), lithium chloride (LiCl), lithium hydroxide (LiOH), lithium nitrate (LiNO ₃ ), lithium chlorate (LiClO). ₃ · H ₂ O) and at least one component selected from the group consisting of lithium perchlorate (LiClO ₄ ), the water retention on the substrate surface is large, and the volatility is low and stable. So good.

The adsorbent is selected from the group consisting of zinc sulfate (ZnSO ₄ ), zinc nitrate (Zn (NO ₃ ) ₂ .6H ₂ O) and zinc iodide (ZnI ₂ ). The at least one acidic substance is suitable for adsorbing and removing basic gas (especially ammonia).

As described in claim 4, the adsorbent is calcium carbonate (CaCO ₃ ), potassium carbonate (K ₂ CO ₃ ), sodium carbonate (Na ₂ (CO ₃ )), potassium hydroxide (KOH) water. Selected from the group consisting of calcium oxide (Ca (OH) ₂ ), sodium hydroxide (NaOH), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), aluminum nitrate (Al (NO ₃ ) ₃ ), and hydrates thereof The at least one basic substance is suitable for adsorbing and removing acidic gas (especially SO _x , NO _x ).

As described in claim 5, the adsorbent is iodine (I ₂ ), potassium iodide (KI), calcium iodide (CaI ₂ ), sodium iodide (NaI), potassium iodate (KIO _3). ), At least one reducing agent selected from the group consisting of calcium iodate (Ca (IO ₃ ) ₂ ) and sodium iodate (NaIO ₃ ), adsorbs and removes (decomposes) ozone (O ₃ ) gas. Suitable for

  As described in claim 6, in order to exert the effect of the support containing the adsorbent and the humectant, the support is supported at a ratio of 5% by weight or more with respect to the weight of the base material. It is necessary to Even if the support is supported on the surface of the substrate in an amount of more than 300% by weight, the effect is not changed. Here, the abundance ratio (weight basis) between the adsorbent and the humectant in the support is preferably adsorbent: humectant = 100: 1 to 100: 30.

As described in claim 7, in order for the support containing the adsorbent and the humectant to exert its effect, it is supported on the surface of the substrate at a rate of 1 g / m ² or more. There is a need. Even if the support is supported on the surface of the substrate in an amount of more than 600 g / m ² , the effect is not changed. Here, in order for the adsorbent to fully exhibit its function, it is preferable that the adsorbent is present on the surface of the substrate in an amount of 1 to 600 g / m ² , more preferably 50 to 500 g / m ² . Moreover, in order for a moisturizer to fully exhibit the function, it is preferable that 1-100 g / m < ² > of moisturizer exists in the surface of the said base material.

  As described in claim 8, the base material is polypropylene, polyacetal, polyarylate, polyamide, polyimide, polycarbonate, polyethylene, polyester, polyethylene terephthalate, polyether ether ketone, polyether sulfone, polyphenylene sulfide, carbon. Relatively wet when it is at least one substance selected from the group consisting of fiber, silicon carbide, phenolic resin, glass, silica / alumina, liquid crystal polymer, natural cellulose, rock wool, wool, cotton, hemp and silk Since the property is good, the familiarity between the support and the substrate is good.

  In addition, as described in claim 9, by molding the gas adsorption filter medium according to any one of claims 1 to 8 into a predetermined shape, it is excellent in the performance of removing harmful gases in the air, It is possible to provide a gas adsorption filter having a small amount of re-emission of outgas etc. and having flame retardancy.

  As described in claim 10, by forming the base material of the gas adsorption filter in the form of paper, honeycomb, mini-pleats, felt or fine packing, the surface area is large and the pressure loss is small. A filter can be provided.

  In addition, as described in claim 11, the fan / filter combined unit including the gas adsorption filter medium according to any one of claims 9 and 10, the ventilation means, and the dust filter is provided in air. It is excellent in the performance of removing harmful gases, has little re-release of a small amount of outgas, etc., and has flame retardancy. Such a fan / filter composite unit is suitable for installation in a clean room for semiconductor manufacturing which is also affected by a small amount of outgas.

Embodiments of the present invention will be described below with reference to the drawings.
The present invention relates to a gas adsorption filter medium, a gas adsorption filter using the same, and a fan / filter unit. These are used, for example, in clean rooms, air purifiers, and the like.

The gas-adsorbing filter medium according to the present invention includes an adsorbent that adsorbs a predetermined gas on a substrate surface composed of fibers, and a humectant that absorbs moisture in the air and retains moisture on the substrate surface. It is supported. The fiber is not particularly limited as long as it has wettability that allows the adsorbent and the humectant to be held on the surface thereof. If a porous material is used as a base material, outgassing due to physical adsorption / desorption may occur. Therefore, it is not porous, for example, nitrogen adsorption BET specific surface area is 300 m ² / base material (g) or less. It is preferable to employ the substrate. Considering wettability, specific surface area, etc., for example, polypropylene, polyacetal, polyarylate, polyamide, polyimide, polycarbonate, polyethylene, polyester, polyethylene terephthalate, polyether ether ketone, polyether sulfone, polyphenylene sulfide, carbon fiber, silicon carbide Phenol resin, glass, silica / alumina, liquid crystal polymer, natural cellulose, rock wool, wool, cotton, hemp or silk, or a mixed material thereof is preferable. The shape of these fibers may be a normal columnar shape, or a deformed fiber may be employed. As an example of the gas adsorption filter medium, a nonwoven fabric composed of these fibers is used as a sheet-like gas adsorption filter medium. The shape of the gas-adsorbing filter medium is not limited to a sheet shape, and may take other shapes.

As the moisturizing material, a material having low volatility and high water retention is preferable. This absorbs the surrounding moisture, so that moisture is retained on the surface of the base material, and a region rich in moisture is formed. For example, lithium bromide (Li ₂ Br), lithium chloride (LiCl), lithium hydroxide (LiOH), lithium nitrate (LiNO ₃ ), lithium chlorate (LiClO ₃ 1 / 2H ₂ O) and lithium perchlorate ( LiClO ₄ ). About each moisturizing agent, it is preferable to carry | support in 1-180g per base-material (m < ² >), for example, Preferably it is 1-100g, Most preferably, it is 5-100g.

As the adsorbent, an acidic substance, a basic substance, a reducing agent, an oxidizing agent, and the like can be appropriately selected according to the gas species to be adsorbed. Preferably, a water-soluble (polar) compound that is easily retained in a water-rich region formed around the humectant is suitable for the adsorbent used in the present invention. For example, in order to adsorb basic gases such as ammonia and trimethylamine, acidic gases such as zinc sulfate (ZnSO ₄ ), zinc nitrate (Zn (NO ₃ ) ₂ .6H ₂ O), and zinc iodide (ZnI ₂ ) are used. A substance is selected as the adsorbent. In particular, although zinc sulfate is easy to dry and peel off from the surface of the base material, the peeling is suppressed in the state where the humectant coexists. In order to adsorb acidic gases such as hydrogen sulfide, methyl mercaptan, nitrogen oxide (NO _x ), sulfur oxide (SO _x ), calcium carbonate (CaCO ₃ ), potassium carbonate (K ₂ CO ₃ ), sodium carbonate ( Na ₂ (CO ₃ )), potassium hydroxide (KOH), calcium hydroxide (Ca (OH) ₂ ), sodium hydroxide (NaOH), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), aluminum nitrate (Al ( Basic materials such as NO ₃ ) ₃ ) and their hydrates are selected as adsorbents. In order to adsorb ozone gas and particularly sulfur-based acidic gas, iodine (I ₂ ), potassium iodide (KI), calcium iodide (CaI ₂ ), sodium iodide (NaI), potassium iodate (KIO ₃ ), iodine Reducing agents such as calcium acid (Ca (IO ₃ ) ₂ ) and sodium iodate (NaIO ₃ ) are selected as adsorbents. Living odor mainly contains ammonia and trimethylamine derived from the human body, and tobacco odor contains ammonia, aldehydes and acetic acid. In order to remove these, the adsorbents described above may be used in appropriate combination.

  If necessary, an adsorbent having both flame retardancy such as phosphoric acid, trichlorophosphoric acid, ammonium phosphate, tricotine phosphoric acid, antimony trioxide, tetrabromobisphenol A, hexabromocyclodecane, zirconium hydroxide and the like is added. The flame retardancy of the gas adsorption filter medium is further improved.

The amount of the supported material containing the adsorbent and the humectant is such that the function is sufficiently exerted, and the range in which peeling / dropping hardly occurs, for example, exceeds 1% by weight with respect to the weight of the substrate. It can be 400% by weight or less. Preferably it is 5-300 weight%, Most preferably, it is 50-250 weight%. Alternatively, the support containing the adsorbent and the humectant can be supported on the surface of the base material at a rate of 0.1 to 800 g / m ² , preferably 1 to 600 g / m ² , Particularly preferably, it can be supported at a rate of 50 to 500 g / m ² .

  The gas adsorption filter medium can be formed into an arbitrary predetermined shape to form a gas adsorption filter. For example, when the above-mentioned sheet-like gas adsorption filter medium is formed into a honeycomb, corrugated honeycomb, or mini-pleat shape, a gas adsorption filter having a large contact area of passing air and a small pressure loss is obtained. Alternatively, the gas adsorption filter medium can be formed into a felt shape, or a fine gas adsorption filter medium having a predetermined shape (for example, spherical shape or chip shape) can be closely packed to form a gas adsorption filter.

  The gas-adsorbing filter medium according to the present invention can be obtained, for example, by impregnating the base material with the above-described solution containing the humectant and the adsorbent, and drying it in a dryer for several hours. Alternatively, it can be obtained by spraying the solution onto a substrate and drying, but is not limited thereto.

  Next, the structure of the gas adsorption filter using the gas adsorption filter medium of the present invention will be described below based on the drawings. In FIGS. 1 to 3, the arrow indicates the direction in which the air to be purified flows.

  FIG. 1 is a perspective view showing an example of a chemical filter (gas adsorption filter) 3 formed by laminating gas adsorption filter media according to the present invention. This chemical filter 3 is formed by laminating a sheet-like gas-adsorbing filter medium into a fine corrugated honeycomb shape. As shown in FIG. 1, a gas containing a gas to be removed passes through the voids of the honeycomb. In addition, in order for the filter (filter medium) according to the present invention to exert its effect sufficiently, it should be used in an environment where the moisture can be brought into contact with the moisturizing agent (for example, relative humidity of 35% or more). preferable. In addition, it may be preferable to maintain a certain humidity (for example, 10% or more) even during storage.

  FIG. 2 shows an example in which the chemical filter 3 described above is used in a fan / filter composite unit 9 and a clean room system used for semiconductor manufacturing and the like. As shown in FIG. 2, the outside air introduction hole (not shown) provided in the ceiling portion side wall of the clean room (working area) 4 passes outside air through the air conditioner 2 and the outside air conditioner 1 provided on the outside thereof. It is provided in the clean room 4 so that it can be introduced. Clean room 4 The chemical filter 3 and a high efficiency particulate air (HEPA) filter as a dust collection filter 7 sandwich the fan 8 in the vicinity of the ceiling of the clean room 4 on the passage path of the outside air introduced from the outside air introduction hole. The fan / filter composite unit 9 is provided in a stack. The fan / filter combined unit 9 may be formed by laminating the chemical filter 3, the dust collection filter 7, and the fan 8 in this order from the upstream side in the order of passage of air. In addition, a HEPA filter is given as a representative example of the dust collection filter 7. However, the filter is not limited to this as long as the filter has a dust collection function. For example, ULPA (Ultra Low Penetration Air) having a high dust collection capability for finer particles. ) A filter may be employed.

  Further, a semiconductor manufacturing apparatus that is a local clean booth 5 is installed inside the clean room 4, and a chemical filter 3 is disposed on a passage path of air introduced into the semiconductor manufacturing apparatus 5. The air discharged from the floor of the clean room 4 moves to the maintenance zone 6 where it is further filtered by the chemical filter 3.

  The outside air introduced into the clean room 4 is first purified by passing through the external air conditioner 1 to which the chemical filter 3 is attached, and is sent to the air conditioner 2. Enter 4 Next, the chemical filter 3 constituting the fan / filter composite unit 9 absorbs and filters most of a trace amount of harmful gas contained in the air. Next, other particulate impurities are filtered by the stacked HEPA filters 7 and then supplied from the ceiling into the clean room 4. A part of the air supplied into the clean room 4 is introduced into the semiconductor manufacturing apparatus 5. At this time, the remaining trace amount of harmful gas is further removed by the chemical filter 3 provided separately before being introduced into the semiconductor manufacturing apparatus 5. The air introduced into the clean room 4 is then discharged to the maintenance zone 6 through an exhaust hole (not shown) under the floor. In the maintenance zone 6, air is further removed by the chemical filter 3 to remove the remaining trace amount of harmful gas, and then a part thereof is released to the outside. The remaining air is again introduced into the air conditioner 2, passes through the chemical filter 3 provided therein, removes the remaining trace amount of harmful gas, passes through the fan / filter combined unit 9, and is clean room 4. Will be returned within.

  Thus, in the clean room system provided with the chemical filter 3 according to the present invention everywhere, the outgas emission from the filter medium itself is greatly suppressed and the ability to collect a trace amount of harmful gas is excellent. Very clean air circulates inside it, which is very suitable for applications such as semiconductor manufacturing and precision machine manufacturing.

  As an application of the clean room system of the gas adsorption filter medium according to the present invention, for example, a gas purification device can be mentioned. The gas purification apparatus may be configured as a local clean booth such as the semiconductor manufacturing apparatus 5 on which the above-described chemical filter 3 is mounted, and is externally attached to the outside of the clean room 4 as shown as the external air conditioner 1. It may be configured as a conditioner. Alternatively, for example, the gas adsorbing filter medium, the gas adsorbing filter, or the fan / filter combined unit according to the present invention may be mounted inside an air purifier or an air conditioner. These also have high removal performance for trace gases such as ammonia, trimethylamine, methyl mercaptan, hydrogen sulfide, SOx, NOx, ozone, etc. contained in the air, have a long service life and little outgassing. A clean space can be realized.

[Create gas adsorption filter]
The base material was created as follows. A corrugator (corrugated plate) was used to corrugate (corrugate plate) a flat sheet made of pulp fiber having a basis weight of about 150 g / m ² and a thickness of 0.3 mm to obtain a corrugated plate. The corrugated honeycomb structure was obtained by stacking 50 corrugated sheets. Regarding the corrugated waveform, considering the ventilation resistance and adsorption efficiency, the distance between the crests on one side of the corrugated plate is 4.8 mm, and the height from the flat plate to the crest is 2.0 mm. It was. The number of cells in the honeycomb was 80 / in 2.

  The base material is immersed in an aqueous solution in which a moisturizing material and an adsorbent are blended at a predetermined ratio, and dried to obtain a corrugated honeycomb-like gas adsorption filter carrying the moisturizing material and the adsorbent at a predetermined ratio. It was. The types of humectants and adsorbents and the loadings thereof are individually shown below.

[Experimental Example 1]
A gas adsorption filter in which zinc sulfate as an adsorbent was supported at a ratio of 120 g / base material (m ² ) and lithium chloride as a moisturizing material at a ratio of 28 g / base material (m ² ) was obtained. When the pressure loss of this gas adsorption filter was measured by the method prescribed in JIS B 9901, it was Δp = 8 mmAq under the condition of a linear velocity of 3.0 mm / sec.

[Experimental example 2]
The gas adsorption filter which carry | supported the potassium iodide as an adsorbent in the ratio of 105 g / base material (m < ² >) and the lithium chloride as a moisturizing material in the ratio of 12 g / base material (m < ² >) was obtained on the said base material. When the pressure loss of this gas adsorption filter was measured by the method prescribed in JIS B 9901, it was Δp = 1.7 mmAq under the condition of a linear velocity of 1.7 mm / sec.

[Experimental Example 3]
Ratio of potassium iodide as adsorbent to 75 g / base material (m ² ) and potassium carbonate 263 g / base material (m ² ), lithium chloride as moisturizer 30 g / base material (m ² ) A gas adsorption filter supported by the above was obtained. When the pressure loss of this gas adsorption filter was measured by the method prescribed in JIS B 9901, it was Δp = 0.7 mmAq under the condition of a linear velocity of 0.7 mm / second.

[Comparative Example 1]
A gas adsorption filter in which zinc sulfate as an adsorbent was supported at a ratio of 120 g / base material (m ² ) without supporting the moisturizing material on the base material was obtained.

[Comparative Example 2]
A gas in which citric acid as an adsorbent is supported at a rate of 72 g / base material (m ² ) and phosphoric acid as a flame retardant is supported at a rate of 18 g / base material (m ² ) without supporting a moisturizing material on the base material. An adsorption filter was obtained.

[Comparative Example 3]
A gas adsorption filter was obtained in which the moisturizing material was not supported on the base material, and potassium iodide as an adsorbent was supported at a rate of 105 g / base material (m ² ).

[Low concentration basic gas removal performance evaluation method]
Using ammonia gas as a representative index of basic gas, the low concentration gas removal performance of the gas adsorption filter was evaluated as follows.
That is, the gas adsorption filter (150 mm square, 140 mm thick test piece) of Experimental Example 1 according to the present invention is attached to the one-pass removal performance test apparatus, and the room air (test air containing the above trace gas: temperature 23 ° C.) , Relative humidity 50%) was introduced into the gas adsorption filter at a linear velocity of 3.0 m / sec. Air was collected wet at the inlet and outlet sides of the gas adsorption filter at regular intervals, and the ammonia concentration in the air (inlet ammonia concentration, outlet ammonia concentration, unit: ppb) was measured. In the wet collection, a gas absorption bottle containing an absorption liquid and a mini pump were set as one set, and sampled air was sampled in the absorption liquid by bubbling and concentrated collection was performed. As the absorbing solution, 100 mL of ultrapure water having a specific resistivity of 18.0 MΩ to 18.3 MΩ was used, and the sampling condition was 360 L suction sampling at a suction flow rate of 2 L per minute. The collected solution was analyzed with an ion exchange chromatography analyzer, and the ammonia removal rate of the gas-adsorbing filter medium was calculated from the obtained ammonia ion concentration using the following formula (Equation 1). The analysis conditions for ion exchange chromatography are shown in Table 1. Wet collection (sampling) was performed three times for about 60 minutes each about 50 hours after the start of aeration, and the average data was obtained as the inlet ammonia concentration and the outlet ammonia concentration, and the removal rate (%) was calculated.

  The gas adsorption filter of Comparative Example 1 (150 mm square, 140 mm thick test piece) and the gas adsorption filter of Comparative Example 2 (150 mm square, 140 mm thick test piece) were also evaluated in the same manner.

As a result of the one-pass removal performance test, in the gas adsorption filter of Experimental Example 1, the inlet ammonia concentration was 8.36 ppb, whereas the outlet ammonia concentration was 0.16 ppb, and the removal rate was 98.1%. there were.
In contrast, in the gas adsorption filter of Comparative Example 1, the inlet ammonia concentration was 19.8 ppb, whereas the outlet ammonia concentration was 7.2 ppb, and the removal rate was 63.6%.
In the gas adsorption filter of Comparative Example 2, the inlet ammonia concentration was 12.4 ppb, whereas the outlet ammonia concentration was 0.41 ppb, and the removal rate was 96.7%. However, it deteriorated by the acid carried by the base material mainly composed of cellulose, discolored and generated odor.

  From the above evaluation, the gas collection rate (removal rate) of the filter varies greatly depending on the presence or absence of lithium moisturizing material, and when other compounds are loaded, the base material deteriorates and outgassing occurs. Became clear. Thus, it can be seen that the gas adsorption filter medium and the filter according to the present invention achieve both the high adsorption ability and the suppression of outgas generation, and are extremely superior to the conventional one.

[Low concentration oxidant gas removal performance evaluation method]
Using ozone gas as a representative index of the oxidant, the low concentration oxidant gas removal performance of the gas adsorption filter was evaluated.
That is, the gas adsorption filter (150 mm square, 80 mm thickness test piece) of Experimental Example 2 according to the present invention is attached to a one-pass removal performance test apparatus, and indoor air (test air containing the above trace gas: temperature 23 ° C., (Relative humidity 50%) was introduced into the gas adsorption filter at a linear velocity of 1.7 m / sec. Air was introduced into an ozone automatic analyzer (compact digital ozone analyzer A21-ZX: manufactured by MK Scientific) at regular time intervals on the inlet side and outlet side of the gas adsorption filter, and the ozone concentration was measured.

  The gas adsorption filter of Comparative Example 2 (150 mm square, 80 mm thick test piece) was similarly evaluated.

As a result of the one-pass test, in the gas adsorption filter of Experimental Example 2, the inlet ozone concentration was 5.0 ppb, whereas the outlet ozone concentration was 0.75 ppb, and the removal rate was 85.0%. .
In contrast, in the gas adsorption filter of Comparative Example 3, the inlet ozone concentration was 5.0 ppb, whereas the outlet ozone concentration was 2.55 ppb, and the removal rate was 49.0%.

  From the above evaluation, the gas collection rate (removal rate) of the filter greatly changes depending on the presence or absence of lithium chloride as a moisturizing material, and the gas adsorption filter medium and filter according to the present invention have high ozone gas adsorption ability, It turns out that it is a very superior thing compared to the thing.

[Low concentration acid gas removal performance evaluation method]
Using sulfurous acid gas (SO ₂ ) as a representative index of acid gas, except for the conditions shown in Table 2, the experiment example 2 (150 mm square, 80 mm thickness test) was performed in the same manner as the low concentration basic gas removal performance evaluation method described above. Piece) and Experimental Example 3 (150 mm square, 25 mm thick test piece) gas adsorption filters were evaluated for low concentration acidic gas removal performance.

  As a result of the one-pass removal performance test, in the gas adsorption filter of Experimental Example 2, the inlet sulfurous acid concentration was 4.03 ppb, whereas the outlet sulfurous acid concentration was 0.03 ppb, and the removal rate was 99.3%. there were. Similarly, in the gas adsorption filter of Experimental Example 3, the inlet sulfite concentration was 11.4 ppb, whereas the outlet sulfite concentration was 0.50 ppb, and the removal rate was 95.6%.

  From the above evaluation, by adding lithium chloride as a moisturizing material, the filter according to the present invention maintains a high acid gas collection rate while suppressing the generation of outgas, as in the basic gas removal performance test. Became clear.

[Self-flame retardant evaluation]
In accordance with the UL94 standard, the self-flame retardant properties of the gas adsorption filters of Experimental Examples 1 to 3 and Comparative Example 1 were evaluated (the average value of the results of testing five samples for each sample was used as the evaluation). The length of the blue flame of the gas burner (burner caliber: 9.5 mm, burner length: 102 mm) was adjusted to 19 mm, and this was tested (lower end width: 12.7 mm, length: 127.0 mm, thickness: 3). .1 mm) for 10 seconds, the specimen was moved away from the flame, and the self-extinguishing time at this time was defined as s1 (seconds). Subsequently, after a flame was applied to the center of the lower end of the specimen for 10 seconds, the specimen was moved away from the flame, and the self-extinguishing time at this time was defined as s2 (seconds). After this, the time until the smolder accompanied by smoke generation was settled was defined as s3 (seconds).

The gas adsorption filter of Experimental Example 1 exhibited excellent self-extinguishing properties such as s1 = 0 seconds, s2 = 0 seconds, and s3 = 5.2 seconds. There was no melting drop (drip) of the specimen.
The gas adsorption filter of Experimental Example 2 showed excellent self-extinguishing properties such as s1 = 0 seconds, s2 = 0 seconds, and s3 = 8.8 seconds. There was no melting drop (drip) of the specimen.
The gas adsorption filter of Experimental Example 3 showed excellent self-extinguishing properties such as s1 = 0 seconds, s2 = 0 seconds, and s3 = 8.8 seconds. There was no melting drop (drip) of the specimen.
In addition, the result of the gas adsorption filter of the comparative example 1 was inferior to the result of Experimental example 1-3, and was inferior to self-extinguishing property.

  As a gas-adsorbing filter medium that has little re-emission of a small amount of outgas and the like, has flame retardancy, and is excellent in the performance of removing harmful gases in the air, it can be used for a fan / filter combined unit constituting a clean room.

The perspective view of the gas adsorption filter medium which concerns on this invention Schematic diagram of a clean room using a gas adsorption filter medium according to the present invention

Explanation of symbols

1 External air conditioner 2 Air conditioner 3 Gas adsorption filter medium 4 Clean room 5 Semiconductor manufacturing equipment (local clean booth)
6 Maintenance zone 7 HEPA filter (dust collection filter)
8 Fan 9 Fan / filter combined unit

Claims (11)

  A gas-adsorbing filter medium carrying an adsorbent that adsorbs a predetermined gas on a substrate surface and a humectant that absorbs moisture in the air and retains moisture on the substrate surface.   The gas adsorption filter medium according to claim 1, wherein the humectant contains at least one component selected from the group consisting of lithium bromide, lithium chloride, lithium hydroxide, lithium nitrate, lithium chlorate and lithium perchlorate.   The gas adsorption filter medium according to claim 1 or 2, wherein the adsorbent is at least one acidic substance selected from the group consisting of zinc sulfate, zinc nitrate, and zinc iodide.   The adsorbent is at least one basic substance selected from the group consisting of calcium carbonate, potassium carbonate, sodium carbonate, potassium hydroxide, calcium hydroxide, sodium hydroxide, aluminum sulfate and aluminum nitrate, and hydrates thereof. The gas adsorption filter medium according to claim 1 or 2.   The adsorbent is at least one reducing agent selected from the group consisting of iodine, potassium iodide, calcium iodide, sodium iodide, potassium iodate, calcium iodate and sodium iodate. Gas adsorption filter media.   The loaded material containing the adsorbent and the humectant is loaded at a ratio of more than 5% by weight and 300% by weight or less with respect to the weight of the base material. Gas adsorption filter media. The carrier containing said humectant with the adsorbent on the surface of the substrate, any one gas adsorption medium according to claim 6 carrying at a rate of 1~600g / m ^2.   The base material is polypropylene, polyacetal, polyarylate, polyamide, polyimide, polycarbonate, polyethylene, polyester, polyethylene terephthalate, polyether ether ketone, polyether sulfone, polyphenylene sulfide, carbon fiber, silicon carbide, phenol resin, glass, silica The gas adsorption filter medium according to any one of claims 1 to 7, which is at least one substance selected from the group consisting of alumina, liquid crystal polymer, natural cellulose, rock wool, wool, cotton, hemp and silk.   The gas adsorption filter which shape | molded the gas adsorption filter material of any one of Claims 1-8 in the predetermined shape.   The gas adsorption filter according to claim 9, wherein the predetermined shape is a paper shape, a honeycomb shape, a mini-pleat shape, a felt shape, or a finely packed shape.   11. A fan / filter combined unit comprising the gas adsorption filter according to claim 9, a ventilation means, and a dust removal filter.

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