JPWO2019151283A1 - Manufacturing method of gas adsorbent, deodorant fiber sheet and gas adsorbent - Google Patents

Abstract

In the present invention, a gas having excellent adsorption performance for low boiling point aldehydes and also having excellent performance for suppressing desorption of low boiling point aldehydes and low polar gases once adsorbed by this gas adsorbent from the gas adsorbent. An object of the present invention is to provide an adsorbent. The solution is to contain a proton-type Y-zeolite and a water-soluble acid hydrazide compound, the proton-type Y-zeolite contains SiO2 and Al2O3, and the SiO2 and Al2O3 in the proton-type Y-zeolite. It is a gas adsorbent having a molar ratio of (SiO2 content / Al2O3 content molar) of 2 or more and 20 or less.

Description

The present invention relates to a gas adsorbent and a deodorant fiber sheet using the gas adsorbent.

In recent years, with the growing desire to improve the living environment, it is required that the filter medium, which is a deodorant fiber sheet, can remove volatile organic compounds (VOCs) in addition to dust existing in the air to purify the air. .. In particular, in a vehicle such as an automobile, since many parts using binders and paints are present in a narrow space, VOCs are likely to be present at a high concentration, and efficient removal of VOCs by a filter medium is required.

Recently, development has been promoted in order to suppress the amount of VOCs generated from automobile parts, and the amount of organic solvents such as toluene and xylene generated has been suppressed to below the guideline value of the Ministry of Health, Labor and Welfare. It is difficult to take measures against low boiling point aldehydes such as formaldehyde and acetaldehyde depending on the source, and a filter medium capable of removing low boiling point aldehydes is required.

Until now, as a filter medium having a VOC removing ability, a filter medium containing activated carbon as an adsorbent has been widely known. However, among VOCs, acetaldehyde and formaldehyde have a low boiling point and high polarity, so that they are difficult to remove with activated carbon. Therefore, it is necessary to use a large amount of activated carbon, so that the filter medium has high aeration resistance. Further, in the filter medium using this technique, activated carbon is based on the physical adsorption ability, and substances other than acetaldehyde to be removed are also adsorbed and further concentrated. Since these odorous components are not trapped by chemical bonds, the concentrated odorous components are released at once due to environmental factors such as changes in temperature and humidity. In that case, it is also known that the odorous component, which was not a problem at the original concentration, is recognized as a bad odor.

Therefore, in recent years, filter media using silica gel or zeolite carrying an acid hydrazide compound have been used, and these are excellent in adsorption performance of low boiling point aldehydes. The fiber sheet described in Patent Document 1 is excellent in adsorption performance of low boiling point aldehydes, and can remove low boiling point aldehydes with a small amount of adsorbent. In addition, the amount of low-boiling aldehydes and low-polarity gases such as toluene and xylene once adsorbed on the adsorbent in the fiber sheet can be reduced from the adsorbent as compared with the filter medium using a large amount of activated carbon. There is.

In addition, Patent Document 2 discloses an adsorbent in which acid hydrazide is added to A-type zeolite or X-type zeolite. Patent Document 3 discloses an adsorbent in which an amine compound is added to zeolite.

JP-A-2007-167632 Japanese Unexamined Patent Publication No. 2011-83756 Japanese Unexamined Patent Publication No. 08-280781

However, in the filter medium having the form of the fiber sheet of Patent Document 1, an adsorbent having a wide pore size distribution centered on the mesopores was used. Therefore, when the amount of chemical adsorption of low boiling point aldehydes by the acid hydrazide compound is saturated, secondary odor occurs due to the desorption of gas components with low odor thresholds such as once adsorbed low boiling point aldehydes and low polar gases. Was still there. Further, the adsorbents described in Patent Documents 2 and 3 have a problem that the adsorption performance of low boiling point aldehydes is insufficient under dynamic conditions such as an air filter in which air is flowing.

The present invention is intended to solve the above problems, has excellent adsorption performance of low boiling point aldehydes under dynamic conditions such as an air filter in which air is flowing, and is once adsorbed by an adsorbent. An object of the present invention is to provide a gas adsorbent having excellent performance of suppressing desorption of low boiling point aldehydes and low polar gases from the adsorbent.

The present invention for solving the above problems is characterized in that it has any of the following configurations.
(1) The proton-type Y-zeolite contains a water-soluble acid hydrazide compound, and the proton-type Y-zeolite contains SiO ₂ and Al ₂ O ₃ , and the SiO in the proton-type Y-zeolite _A gas adsorbent having a molar ratio of ₂ to Al ₂ O ₃ (moll of SiO ₂ / molar of Al ₂ O ₃ ) of 2 or more and 20 or less.
(2) The gas adsorbent of (1) further containing activated carbon.
(3) The gas adsorbent of (2), wherein the activated carbon has a specific surface area of 900 to 1300 m ² / g.
(4) The gas adsorbent according to (2) or (3), wherein the content mass ratio of the activated carbon to the Y-type zeolite (the content mass of the activated carbon / the content mass of the Y-type zeolite) is 0.05 to 0.50. ..
(5) A deodorant fiber sheet having the gas adsorbent according to any one of (1) to (4).
(6) The deodorant fiber sheet of (5), wherein the content of the gas adsorbent per unit area is 10 to 100 g / m ² .
(7) An air filter unit including the deodorant fiber sheet of (5) or (6).
(8) After mixing sodium aluminate and sodium silicate to obtain a mixture, the mixture is heated at 90 to 120 ° C. to obtain a zeolite, and the zeolite is treated with an ammonium nitrate solution at 100 to 120 ° C. A method for producing a gas adsorbent, which comprises a step, a step of calcining the zeolite with superheated steam at 500 to 800 ° C., and a step of impregnating the zeolite with a water-soluble acid hydrazide compound in this order.

It has excellent adsorption performance of low boiling point aldehydes under dynamic conditions such as an air filter, and gas adsorption of low boiling point aldehydes and low polar gases once adsorbed by the gas adsorbent. It is possible to provide a gas adsorbent having excellent performance of suppressing desorption from the agent.

The gas adsorbent of the present invention contains a proton-type Y-zeolite (hereinafter, may be simply referred to as “Y-type zeolite”) and a water-soluble acid hydrazide compound. Here, the proton-type zeolite refers to a zeolite whose cation exchange site is a proton (H ⁺ ).

Then, Y-type zeolite of proton type, containing SiO ₂ and _Al 2 _{O 3,} molar / Al of molar ratio (SiO ₂ with SiO ₂ and _Al 2 _{O 3} in the Y-type zeolite of proton type _The molar content of ₂ O ₃ ) is 2 or more and 20 or less. This gas adsorbent has excellent adsorption performance of low boiling aldehydes (hereinafter, may be referred to as "dynamic adsorption performance") under dynamic conditions such as an air filter in which air is flowing. , It is excellent in the ability to suppress the desorption of low boiling aldehydes and low polar gases once adsorbed on the gas adsorbent from the gas adsorbent (hereinafter, may be referred to as "desorption suppression performance").

It is important that the zeolite contained in the gas adsorbent of the present invention is a Y-type zeolite. The Y-type zeolite has a bottleneck-type pore structure with a pore diameter of 7.4 Å at the entrance of the pores. Since the inlet pore diameter is larger than that of the A-type zeolite, the water-soluble acid hydrazide compound can be easily attached, and the amount of the attachment can be increased. As a result, the dynamic adsorption performance can be improved. Further, since the Y-type zeolite has a structure in which the pore inlet is larger than that of the A-type zeolite, it is possible to promote the entry of low boiling point aldehydes to be removed into the zeolite pores, and as a result, the dynamic adsorption performance. Can be enhanced. On the other hand, since Y-type zeolite does not have mesopores like porous silica, it is possible to inhibit the entry of high boiling point aldehydes and low polar gases into the pores and suppress the accumulated amount. .. As a result, the desorption suppressing performance of the gas adsorbent becomes excellent.

In addition, the chemical reaction between low boiling point aldehydes and water-soluble acid hydrazide compounds is a multi-step reaction. Acetaldehyde, which is a representative component of low boiling point aldehydes, will be described as an example. The chemical reaction between the acid hydrazide compound and acetaldehyde is a multi-step reaction in which the intermediate product carbinolamine is desorbed from water. The multi-step reaction is characterized in that the progress is promoted in the presence of an acid catalyst. Here, the proton-type Y-type zeolite exhibits stronger activity as an acid catalyst than the X-type zeolite. Therefore, the dynamic adsorption performance of the gas adsorbent of the present invention containing the proton-type Y-zeolite and the water-soluble acid hydrazide compound becomes excellent. Although details will be described later, the proton-type Y-type zeolite can be obtained, for example, by subjecting the Y-type zeolite to a dealuminum treatment.

Then, Y-type zeolite proton type employed in the present invention contains SiO ₂ and _Al 2 _{O 3,} molar ratio of SiO ₂ and _Al 2 _{O 3} in the Y-type zeolite of proton type (SiO ₂ (Mole containing / Al ₂ O ₃ ) is 2 or more and 20 or less. Proton-type Y-type zeolite zeolite has a three-dimensional skeleton structure that is a crystalline aluminosilicate, but by adjusting the mixing ratio of the raw material for silica and the raw material for alumina during synthesis, The composition ratio of silicon and aluminum can be controlled.

Here, as the molar ratio of SiO ₂ / Al ₂ O ₃ in the proton-type Y-zeolite increases, the ratio of metal cations present in the crystal lattice decreases. As a result, the affinity for polar substances such as water is weakened, and it has the characteristic of adsorbing non-polar substances more. Therefore, by setting the molar ratio of SiO ₂ / Al ₂ O ₃ of the proton-type Y-zeolite to 20 or less, the decrease in hydrophilicity of the proton-type Y-zeolite is suppressed, and the porous structure is formed. Since the water-soluble acid hydrazide compound can be attached to the inner surface of the pores of the Y-zeolite, the dynamic adsorption performance of the gas adsorbent of the present invention is excellent.

In addition to the above effects, it is possible to suppress the physical adsorption of non-polar or low-polarity gases to the proton-type Y-zeolite. That is, non-polar or low-polarity gases are unlikely to accumulate in the proton-type Y-zeolite. It suppresses the release of large amounts of accumulated non-polar or low-polarity gases, which tend to be other types of zeolites, for some reason. That is, the desorption suppressing performance of the gas adsorbent of the present invention is excellent.

Further, when the above-mentioned molar content ratio is low, the hydrophilicity of the zeolite is increased, and water tends to accumulate in the pores of the zeolite. In that case, it becomes difficult for the aldehyde gas to enter the pores. Therefore, by setting the molar content ratio to 2 or more, it is possible to facilitate the entry of low boiling point aldehydes into the pores of the zeolite even when the air filter provided with the gas adsorbent of the present invention is used, and the gas of the present invention is used. The dynamic adsorption performance of the adsorbent is excellent.

Next, the average particle size of the proton-type Y-zeolite is preferably 0.5 to 1000.0 μm. The smaller the average particle size of the proton-type Y-zeolite, the faster the adsorption rate of low-boiling aldehydes of the gas adsorbent. On the other hand, the proton-type Y-zeolite tends to scatter easily, and the handleability and processability of the proton-type Y-zeolite tend to decrease. Therefore, the average particle size of the proton-type Y-zeolite is preferably 0.5 μm or more, and more preferably 1.0 μm or more. Further, if the average particle size of the proton-type Y-zeolite is large, it may be difficult to produce a proton-type Y-zeolite having such a particle size, and the strength is also fragile. The type zeolite is easily damaged, and on the contrary, dust tends to be generated. The average particle size of the proton-type Y-zeolite is preferably 1000.0 μm or less, and more preferably 700.0 μm or less.

A proton-type Y-zeolite having an average particle size of 100.0 μm or more can be obtained by granulating a powdered proton-type Y-zeolite together with a binder such as silica sol or alumina sol. In particular, in order to maintain the pore characteristics of the proton-type Y-zeolite, it is preferable to adopt a wet granulation method such as a high-speed mixer method or a spray-dry method.

The average particle size referred to here is calculated by the following method. The particle size is expressed as a cumulative weight percentage by measuring the rate of passage through the openings according to the method described in JIS K1474 (2014). Then, the particle size of the integrated value of 50% is defined as the "average particle size". However, if the average particle size is about several μm, the sieve may be clogged. Therefore, proton-type Y-type zeolite is dispersed in a liquid such as water, and diffracted light or scattered light is used. The particle size can be measured.

The BET specific surface area of the proton-type Y-zeolite by the 77K nitrogen adsorption method is preferably 100 m ² / g or more in terms of the BET specific surface area. By setting the specific surface area to 100 m ² / g or more, the effective area as a reaction field of the water-soluble acid hydrazide compound supported by the Y-zeolite is increased. As the area becomes larger, the reaction rate between the gas adsorbent and the low boiling point aldehydes to be removed is further improved, and the dynamic adsorption performance of the gas adsorbent of the present invention becomes excellent. For the above reasons, the BET specific surface area of the proton-type Y-zeolite is more preferably 200 m ² / g or more. The upper limit of the BET specific surface area is not particularly limited, but the BET specific surface area of the proton-type Y-zeolite is preferably 1000 m ² / g or less. This is because if it exceeds this range, there is a disadvantage that the production becomes very difficult, and the handleability is lowered due to the decrease in mechanical strength.

The average pore diameter of the proton-type Y-zeolite means the peak diameter obtained by the MP method, and more specifically, it is obtained by using the adsorption side isotherm obtained by the nitrogen adsorption method at 77 Kelvin (temperature of liquid nitrogen). Be done. The range of the average pore diameter of the preferred proton-type Y-zeolite is 7.0 to 30.0 Å, and more preferably 7.5 to 20.0 Å. Proton-type Y-zeolite has a uniform pore size peak in the range of an average pore size of 7.0 to 10.0 Å, but macropores may be formed in the process of producing secondary particles in the granulation step. To the above range is preferable.

When the average pore diameter is 7.0 Å or more, the acid hydrazide compound easily permeates into the pores of the proton-type Y-zeolite, and the reactivity with low boiling point aldehydes can be enhanced. As a result, the dynamic adsorption performance of the gas adsorbent becomes better. On the other hand, when the average pore diameter of the Y-type zeolite is 30.0 Å or less, it inhibits the entry of high boiling point aldehydes and low polar gases into the pores, which may cause a problem of deodorization, and is used as a gas adsorbent. It is possible to suppress the accumulated amount of these gases. As a result, the desorption suppressing performance of the gas adsorbent becomes excellent.

In the gas adsorbent of the present invention, it is preferable that a water-soluble acid hydrazide compound is attached to the proton-type Y-zeolite in order to adsorb low boiling point aldehydes contained in the VOC gas.

Here, the water-soluble property in the present invention means that it dissolves in 0.5% by mass or more (5 g / L or more) of neutral water at 25 ° C.

The water-soluble acid hydrazide compound is a compound having an acid hydrazide group represented by -CO-NHNH ₂ derived from a carboxylic acid and hydrazine. A nitrogen atom having an unshared electron pair is further bonded to the α-position at the terminal of the hydrazide, which significantly improves the nucleophilic reactivity. This unshared electron pair nucleophilically attacks and reacts with the carbonyl carbon atom of low boiling point aldehydes, and immobilizes the low boiling point aldehydes as hydrazine derivatives, thereby exhibiting the adsorption performance of low boiling point aldehydes. Conceivable.

Among the low boiling point aldehydes, acetaldehyde has an electron-donating alkyl group at the α-position of the carbonyl carbon, so that the carbonyl carbon has a low electrophilicity and is not easily chemically adsorbed. However, since the water-soluble acid hydrazide compound used in the gas adsorbent used in the present invention has high nucleophilic reactivity as described above, it exhibits good chemisorption performance even for acetaldehyde.

Examples of the water-soluble acid hydrazide compound include those containing one or more selected from the group consisting of carbodihydrazide, glutamic acid dihydrazide, succinic acid dihydrazide, and adipic acid dihydrazide. Among these, adipic acid dihydrazide is particularly preferable because it has excellent adsorption performance for low boiling point aldehydes. Further, it is more preferable to use adipic acid dihydrazide and succinate dihydrazide in combination for the purpose of improving the adsorption performance of low boiling point aldehydes.

The content of the water-soluble acid hydrazide compound in the gas adsorbent of the present invention is preferably 0.5 to 20.0 parts by mass with respect to 100.0 parts by mass of the Y-zeolite. By setting the content of the water-soluble acid hydrazide compound to 0.5 parts by mass or more, the adsorption performance of low boiling point aldehydes of the gas adsorbent can be further improved, and the dynamic adsorption performance of the gas adsorbent can be further improved. It can be excellent. For this reason, the content of the water-soluble acid hydrazide compound is more preferably 1.0 part by mass or more. By setting the content of the water-soluble acid hydrazide compound to 20.0 parts by mass or less, the crystallization of the water-soluble acid hydrazide compound adhering to the Y-type zeolite can be suppressed, and the crystallized water-soluble acid hydrazide compound can be suppressed. It is possible to prevent the acid hydrazide compound of the above from blocking the pores of the Y-type zeolite. As a result, the dynamic adsorption performance of low boiling point aldehydes of the gas adsorbent can be improved, and the desorption suppressing performance of the gas adsorbent of the present invention can also be excellent.

The pH of the Y-type zeolite to which the water-soluble acid hydrazide compound used in the present invention is attached is preferably in the range of 4.0 to 7.5 when 5 g is dispersed in 100 g of water at 25 ° C. When the pH is 7.5 or less, the intermediate generated from the reaction of the unshared electron pair of the water-soluble acid hydrazide compound by the nucleophilic attack on the carbonyl carbon atom of the low boiling aldehyde is an acidic reaction field. Since it is protonated at the above, it becomes easy to dehydrate, and the immobilization reaction of the intermediate to the derivative proceeds sufficiently. For the above reasons, the pH is more preferably 7.0 or less. Further, when the pH is 4.0 or more, the unshared electron pair of the water-soluble acid hydrazide compound becomes more active in nucleophilically attacking the carbonyl carbon atom of the low boiling point aldehyde, and the gas adsorbent The dynamic adsorption performance of low boiling point aldehydes is more excellent. The pH was determined by immersing Y-type zeolite in pure water at 25 ° C. with an acid hydrazide compound attached to 5% by mass, stirring lightly, and then leaving it for 10 minutes, and measuring the pH of the solution with a pH meter. To say.

The pH of the Y-type zeolite to which the water-soluble acid hydrazide compound is attached can be adjusted by adding an organic acid. As the organic acid, it is preferable to use an organic acid that does not generate an odor by itself and has low hygroscopicity. Specific examples of the above-mentioned organic acid include adipic acid, sulfanic acid, malic acid, citric acid and the like, which may be appropriately selected depending on the acid hydrazide compound used, and adipic acid is preferably adopted. be able to. Adipic acid is preferable because it keeps the balance of the dispersion liquid stable and does not generate odor or hygroscopicity.

Examples of the method for producing the gas adsorbent of the present invention include the following. That is, a step of mixing sodium aluminate and sodium silicate to obtain a mixture and then heating the mixture at 90 to 120 ° C. to obtain a zeolite, and a step of treating the zeolite with an ammonium nitrate solution at 100 to 120 ° C. A method for producing a gas adsorbent, which comprises a step of calcining the zeolite with superheated steam at 500 to 800 ° C. and a step of imposing a water-soluble acid hydrazide compound on the zeolite in this order.

Here, the following is exemplified as a step of impregnating the zeolite with the water-soluble acid hydrazide compound.
A method of adhering a water-soluble acid hydrazide compound to a Y-type zeolite by putting Y-type zeolite into an aqueous solution in which a water-soluble acid hydrazide compound is dissolved and dispersing it.
A method in which an aqueous solution prepared by dissolving a water-soluble acid hydrazide compound in a solvent is sprayed and applied to a Y-type zeolite, and then the Y-type zeolite is dried.

As the solvent of the latter method, an appropriate solvent can be selected in consideration of the characteristics and workability of the water-soluble acid hydrazide compound. Of these, it is preferable to use an aqueous solvent from the viewpoint of excellent safety and workability, and it is more preferable to use pure water as the solvent. Further, as will be described later, the gas adsorbent may be formed directly on the fiber sheet by drying this treatment liquid on the fiber sheet. The water-soluble acid hydrazide compound is preferably attached to the Y-type zeolite, but more preferably the water-soluble acid hydrazide compound is attached to the pores of the Y-type zeolite.

Further, the gas adsorbent of the present invention preferably contains activated carbon in addition to the water-soluble acid hydrazide compound and the proton-type Y-zeolite. The gas adsorbent of the present invention can further suppress the desorption of once adsorbed VOC gas from the gas adsorbent, and further suppress the generation of secondary odor in an air filter using this gas adsorbent. It can be done. Then, when used in an automobile application in which the wind pressure of the airflow passing through the air filter tends to be strong, secondary odor due to desorption of odorous gas from the deodorant fiber sheet is remarkably generated. Since the air filter using the gas adsorbent of the present invention can suppress secondary odor, the air filter using the gas adsorbent of the present invention can be more preferably used for automobile applications.

In the embodiment of the gas adsorbent of the present invention having the proton-type Y-zeolite and activated carbon, the activated carbon is a granular material different from the above-mentioned proton-type Y-zeolite. However, in the deodorant fiber sheet having the gas adsorbent of the present invention (details of the deodorant fiber sheet will be described later), a part of each of the proton-type Y-zeolite and the activated carbon is fixed to each other by an adhesive. It may exist in a state of being.

Here, the Y-type zeolite to which the water-soluble acid hydrazide compound is attached is excellent in the adsorption performance of low boiling point aldehydes under dynamic conditions. Further, even after the amount of chemisorption to low boiling point aldehydes is saturated, the pore shape having a bottleneck-type uniform pore diameter peculiar to Y-zeolite and the molar amount of SiO ₂ / Al ₂ O ₃ in Y-zeolite. By setting the ratio to 20.0 or less, it is possible to significantly suppress the amount of physical adsorption of low boiling point aldehydes and low polar gas components, and the desorption suppressing performance is also excellent.

However, even so, as long as it has a pore structure, it is difficult to completely eliminate the amount of physical adsorption of low-polarity or non-polar gas to Y-type zeolite, and even a slight amount of physically adsorbed low boiling point. Aldehydes and low-polarity or non-polar gases may desorb from the gas adsorbent and be perceived as odorous components when the temperature and humidity change suddenly, such as when the air conditioner is operating. Therefore, when the gas adsorbent further has activated carbon, the activated carbon adsorbs low boiling point aldehydes and low polar or non-polar gases desorbed from the Y-zeolite, and the secondary odor can be further suppressed. It becomes possible (that is, the desorption suppressing performance of the gas adsorbent becomes better).

The average particle size of the activated carbon is preferably 0.5 to 1000.0 μm. The smaller the average particle size of the activated carbon, the faster the adsorption rate of VOC gas, but on the other hand, the average particle size of the activated carbon is preferably 0.5 μm or more because it tends to scatter and the handleability and workability tend to decrease. Is preferably 1.0 μm or more. On the other hand, if the average particle size of the activated carbon is large, there is a tendency that the non-woven fabric on the top of the pleats is easily torn when the air filter unit is processed. Therefore, in consideration of the pleats processability of the deodorant fiber sheet, etc. The average particle size of the activated carbon is preferably 1000.0 μm or less, and more preferably 600.0 μm or less. The particle size of the above-mentioned activated carbon refers to the mass mean diameter based on the JIS K 1474 (2014) activated carbon test method. It is possible to obtain a desired particle size by adjusting a predetermined particle size using a normal classifier. However, if the activated carbon becomes a fine powder of about several μm, the sieve may be clogged. In that case, the activated carbon is dispersed in a liquid such as water, and the particle size is adjusted by using diffracted light or scattered light. Can be measured.

As a raw material for activated carbon, coconut shells, wood-based, coal-based, pitch-based and the like are known, but coconut shells are preferable. The pores of coconut shell activated carbon have a large proportion of small pores as compared with other raw materials, and the ash content as an impurity is also small. That is, since the coconut shell activated carbon has small pores, an intermolecular force with the pore wall effectively acts on the adsorbed odor molecules, and it is difficult to desorb the adsorbed odor molecules, that is, secondary odor is generated. There is a feature that can suppress.

Next, the specific surface area of the activated carbon used in the present invention is preferably 900 to 1300 m ² / g in terms of BET specific surface area. By setting the specific surface area of the activated carbon to 900 m ² / g or more, it is possible to obtain an effective reaction rate as a reaction field with low boiling point aldehydes. Further, by setting the specific surface area of the activated carbon to 1300 m ² / g or less, it is possible to suppress unintentional adsorption of odors leading to secondary odor.

A drug may be carried on the activated carbon. Of these, amine compounds are preferably carried for the purpose of removing low boiling point aldehydes, and among them, primary amine compounds having an amino group are preferable, and acid hydrazide compounds are more preferable.

These amine compounds are adsorbed on the activated carbon or are intercalated while partially reacting with functional groups such as hydroxyl groups and alkali metals remaining on the surface of the activated carbon to obtain activated carbon carrying the amine compounds. be able to.

The amount of the amine compound carried on the activated carbon is preferably 0.5 to 20.0 parts by mass, more preferably 1.0 to 10.0 parts by mass with respect to 100.0 parts by mass of the activated carbon. Adsorption performance of low boiling point aldehydes By setting the content to 0.5 parts by mass or more, the effect of improving the adsorption performance can be obtained. If an excess amount of the amine compound is added, it will crystallize and block the pores of the activated carbon, which may cause powder to fall off. Therefore, the supported amount is preferably 20.0 parts by mass or less.

The mass ratio of activated carbon to Y-type zeolite to which a water-soluble acid hydrazide compound is attached (mass content of activated carbon / mass of Y-type zeolite to which a water-soluble acid hydrazide compound is attached) is in the range of 0.05 to 0.50. Is preferable.

By setting this content mass ratio to 0.05 or more, when the low-boiling aldehydes that the Y-type zeolite unintentionally adsorbs due to the physical adsorption phenomenon are desorbed, these low-boiling aldehydes are placed in the vicinity of the Y-type zeolite. By adsorbing the existing activated carbon, the desorption suppressing performance of the gas adsorbent becomes more excellent. On the other hand, when this content mass ratio is 0.50 or less, the content mass ratio of Y-type zeolite increases, the adsorption performance of low boiling aldehydes becomes better, and the dynamic adsorption performance of the gas adsorbent becomes higher. In addition to being excellent, the gas adsorbent has more excellent desorption suppressing performance because the mass ratio of activated carbon, which is once adsorbed, is easy to desorb low boiling aldehydes.

A deodorant fiber sheet can be obtained by using the gas adsorbent of the present invention. Examples of the method for producing such a deodorant fiber sheet include the following.
(1) A sheet forming method obtained by dispersing gas adsorbent particles in water, adhering to a fiber sheet, and then dehydrating the particles.
(2) An air-laid method obtained by forming a fiber sheet and dispersing gas adsorbent particles together with the fibers in the air.
(3) A method of filling a gas adsorbent between two or more layers of a non-woven fabric or woven fabric, a net-like material, a film, and a film by thermal adhesion.
(4) A method in which a gas adsorbent is bonded and supported on a breathable material such as a non-woven fabric, a woven fabric, or urethane foam by using an emulsion adhesive or a solvent-based adhesive.
(5) A method in which a gas adsorbent is bonded and supported on a breathable material such as a non-woven fabric, a woven fabric, or urethane foam by utilizing the thermoplasticity of a base material or a hot melt adhesive.
(6) A method of mixing and integrating by kneading a gas adsorbent into a fiber or a resin.

An appropriate method can be used depending on the application, but since it is possible to prevent pore clogging of the Y-zeolite itself, the processing methods (1), (2), (3), or (5) can be used. It is preferable to use it.

A specific manufacturing method of the processing method (1) will be described. A method in which a liquid obtained by mixing and dispersing a Y-type zeolite, a water-soluble acid hydrazide compound and a binder resin is applied to the fiber and further dried, or an aqueous solution in which a Y-type zeolite and a water-soluble acid hydrazide compound are mixed is used as a base fiber. The sheet may be further dried after being applied by a coating treatment, or may be further dried after being sprayed by a spray treatment.

Further, the Y-type zeolite and the binder resin may be first fixed to the surface of the fiber sheet, and then an aqueous solution mixed with the acid hydrazide compound may be attached by a dipping treatment or a spray treatment.

The binder resin is not particularly limited, and any kind of resin can be used. For example, acrylic resin, methacrylic resin, urethane resin, ester resin, polyvinyl alcohol resin, silicon resin and the like can be mentioned. Two or more kinds of resins may be mixed. The mass ratio of Y-zeolite to binder resin (mass of Y-zeolite: mass of binder resin) should be in the range of 10: 1 to 1: 1. Adsorption of Y-zeolite and water-soluble acid hydrazide compound and gas. It is preferable in terms of adsorption performance.

At the time of preparation, it is preferable to first disperse the water-soluble acid hydrazide compound and the Y-type zeolite in the solvent, and then disperse the binder resin, because the dispersion can be more uniform.

In the deodorant fiber sheet using the gas adsorbent of the present invention, it is also preferable to further laminate a sheet having a different fiber composition on the fiber sheet on which the Y-type zeolite and the water-soluble acid hydrazide compound are supported as described above. For example, in use as a direct flow type filter, if a bulky and coarse non-woven fabric sheet is laminated on the upstream side, the amount of dust retained can be improved and the service life can be extended. Further, if a non-woven fabric sheet made of ultrafine fibers is laminated on the downstream side, high collection efficiency can be improved.

Further, it is more preferable that the non-woven fabric sheet made of the ultrafine fibers is subjected to an electret treatment. The electret treatment makes it possible to collect submicron-sized and nano-sized fine dust, which is normally difficult to remove, by electrostatic force.

Next, a specific manufacturing method of the processing method (3) will be described. A deodorant fiber sheet can be obtained by integrating a thermoplastic resin as a gas adsorbent and a binder of the present invention arranged between two layers of non-woven fabric by thermal adhesion. First, the deodorant fiber sheet is sufficiently mixed on one of the non-woven fabrics. The stirred gas adsorbent and the thermoplastic resin are sprayed and heat-treated to melt the thermoplastic resin. A heating furnace can be used as the heating method. The heat-treated material can be overlaid with the other non-woven fabric, pressed, and integrated.

Examples thereof include a heat pressing method between rolls, which is often used for finally heat pressing and sheet production, and a flat bed laminating method in which the heat belt conveyors are sandwiched between flat heat belt conveyors.

Examples of the material of the thermoplastic resin include thermoplastic resins such as polyester, polyolefin, polyamide, polyurethane, ethylene-acrylic copolymer, polyacrylate, polyacrylic, polydiene, ethylene-vinyl acetate, polyvinyl chloride, and polystyrene. Of these, polyester and polyolefin are preferable as materials that generate less odor during heating.

The shape of the thermoplastic resin is not particularly specified as long as it is in the form of powder, but examples thereof include spherical, crushed, and fibrous forms.

The melting point of the thermoplastic resin is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, in consideration of the environmental temperature in the room of a mobile vehicle or the like.

The content of the thermoplastic resin is preferably 5 to 40% by mass, more preferably 10 to 35% by mass, based on the content of the gas adsorbent of the present invention. Within such a range, the adhesive strength with the non-woven fabric is further improved, and the ventilation resistance and deodorizing performance of the deodorant fiber sheet are further improved.

As the fibers forming the above-mentioned non-woven fabric, natural fibers, synthetic fibers, inorganic fibers such as glass fibers and metal fibers can be used, and among them, synthetic fibers of thermoplastic resin capable of melt spinning are preferable. Examples of the thermoplastic resin forming the synthetic fiber include polyester, polyamide, polyolefin, acrylic, vinylon, polystyrene, polyvinyl chloride, polyvinylidene chloride, polylactic acid, and the like, which can be selected according to the intended use. Further, a plurality of types may be used in combination.

As the fibers constituting the non-woven fabric, not only those having a circular cross section but also those having a modified cross section and those having a large number of holes and slits on the fiber surface are preferably used. With such a shape, the surface area of the fiber can be increased, and the supportability of the gas adsorbent can be improved in the deodorant fiber sheet using the gas adsorbent of the present invention. The atypical cross-sectional shape referred to here refers to a cross-sectional shape other than a circle, and examples thereof include a flat shape, a substantially polygonal shape, and a wedge shape. Fibers having such an irregular cross-sectional shape can be obtained by spinning using a base having a non-circular hole. Further, a fiber having a large number of holes or slits on the fiber surface can be obtained by alloying and spinning two or more kinds of polymers having different solubility in a solvent, and dissolving and removing the polymer having higher solubility with a solvent. Can be done.

As a method for producing the non-woven fabric, a dry method, a wet method, a spunbond method, a thermal bond method, a chemical bond method, a spunlace method (water flow entanglement method), a spunbond non-woven fabric, and a melt blow non-woven fabric can be used. Since at least one of the two non-woven fabrics can have a uniform basis weight and thickness, a wet non-woven fabric produced by a papermaking method is preferable.

The fiber diameter of the fibers constituting the non-woven fabric may be selected according to the target air permeability and dust collecting performance in the application used as a deodorant fiber sheet. It is preferably 1 to 2000 μm. By setting the fiber diameter to 1 μm or more, more preferably 2 μm or more, it is possible to prevent the gas adsorbent from clogging the surface of the fiber structure and prevent the air permeability from being lowered. Further, by setting the fiber diameter to 2000 μm or less, more preferably 100 μm or less, it is possible to prevent a decrease in the carrying capacity of the gas adsorbent and a decrease in contact efficiency with the treated air due to a decrease in the fiber surface area.

The basis weight of the non-woven fabric is preferably 10 to 500 g / m ² . By setting the basis weight to 10 g / m ² or more, sufficient strength to withstand the processing for supporting the gas adsorbent can be obtained, and the rigidity required to maintain the filter structure when air is aerated can be obtained. .. Further, by setting the texture to 500 g / m ² or less, more preferably 200 g / m ² or less, the gas adsorbent can be uniformly supported even inside the non-woven fabric, and the deodorant fiber sheet has a pleated shape or a honeycomb shape. It is also excellent in handleability during secondary processing.

The thickness of the non-woven fabric is preferably 0.10 mm to 0.60 mm. If it is thin, the gas adsorbent particles may pop out and break the non-woven fabric, and if it is thick, the handleability may be deteriorated.

It is preferable that at least one non-woven fabric is electret-treated. Due to the electret treatment, submicron size and nano size fine dust, which is normally difficult to remove, can be collected by electrostatic force.

Materials constituting the electrette-treated non-woven fabric include polyolefin resins such as polypropylene, polyethylene, polystyrene, polybutylene terephthalate and polytetrafluoroethylene, aromatic polyester resins such as polyethylene terephthalate, and high electricity such as polycarbonate resins. A material having a resistance is preferable.

Further, the non-woven fabric may be composed of components having ancillary functions such as an antibacterial agent, an antifungal agent, an antiallergen agent, an antiviral agent, a vitamin agent, and a flame retardant. These components may be kneaded into fibers or non-woven fabric, or may be attached and supported by post-processing. For example, a non-woven fabric can be obtained by preparing a non-woven fabric by an arbitrary method, preparing an aqueous solution containing a flame retardant and a resin binder, impregnating and drying the non-woven fabric, and fixing the flame retardant.

The content of the gas adsorbent of the present invention in the deodorant fiber sheet is preferably 10 to 100 g / m ² in total of the proton-type Y-zeolite and the water-soluble acid hydrazide compound. By setting the content to 10 g / m ² or more, more preferably 15 g / m ² or more, it is possible to obtain the actual gas adsorption performance of low boiling point aldehydes. Further, by setting the content to 100 g / m ² or less, it is possible to suppress the occurrence of clogging of the deodorant fiber sheet, thereby suppressing the decrease in the air permeability of the deodorant fiber sheet. it can.

An air filter can be constructed using a deodorant fiber sheet. The shape of the deodorant fiber sheet in the air filter may be used as it is in a flat shape, but a pleated type or a honeycomb type should be adopted in order to accommodate more deodorant fiber sheets within the limited dimensions. Is preferable. When the pleated type is used as a direct flow type air filter and the honeycomb type is used as a parallel flow type filter, the contact area of the treated air is increased to improve the collection efficiency and reduce the low voltage at the same time. Can be done.

The pleating method includes a reciprocating method and a rotary method, and any method may be used as long as it is processed in a mountain valley shape. Further, it is desirable to perform separator processing in order to maintain the pleated shape, and from the viewpoint of production efficiency, a method of melt processing a thermoplastic resin such as bead processing or ribbon processing is desirable. Here, it is preferable to use a polyolefin resin having a melting point of 90 ° C. or higher. Since it is expected that the temperature of the air conditioner system in the interior of an automobile will rise to around 80 ° C in summer, a polyolefin resin having a melting point of 90 ° C or higher will be used to provide an air filter that can maintain a pleated shape at low cost. It becomes possible.

The distance between the fold peaks of the air filter using the deodorant fiber sheet provided with the gas adsorbent of the present invention is preferably 2 to 30 mm. If it is less than 2 mm, the folds are too close to each other and there is a lot of dead space, which makes it impossible to use the sheet efficiently, which is not preferable. On the other hand, if it exceeds 30 mm, the folding area of the deodorant fiber sheet becomes small, and the removal effect according to the thickness of the air filter cannot be obtained, which is not preferable.

Further, it is preferable that the air filter using the gas adsorbent of the present invention is used by being housed in a frame from the viewpoint of air processing efficiency and handleability.

Hereinafter, the present invention will be specifically described with reference to Examples. The evaluation method of each characteristic of the deodorant fiber sheet according to this embodiment is described below.

[Measuring method]
(1) Average particle size (μm)
For zeolite and activated carbon, the average particle size is 50% mass average diameter measured based on the activated carbon test method of JIS K 1474 (2014).

(2) Metsuke (g / m ² )
The mass of the measurement sample cut into 25 cm x 25 cm was measured for 4 sheets using a mass meter (FY-300 manufactured by A & D Co., Ltd.), and the average value was converted to the mass per 1 m ² and the number after the decimal point was changed. Round off the second place to make a basis weight. The basis weight of the deodorant fiber sheet is also measured by the same method as the above-mentioned measuring method.

(3) Thickness (mm)
For the measurement sample cut into 10 cm x 10 cm, 10 points were randomly measured using a thickness gauge (manufactured by Daiei Kagaku Seiki Co., Ltd., model FS-60DS, stylus area 2500 mm ² , measurement load 0.5 KPa), and the average value was calculated. And the thickness. The thickness of the deodorant fiber sheet is also measured by the same method as the above-mentioned measuring method.

(4) the molar ratio of _SiO 2 / _Al 2 _{O 3} in _SiO 2 / _Al 2 _{O 3} molar ratio Y zeolite in zeolite Y, X-ray fluorescence analyzer (XRF) manufactured by Shimadzu Corporation (VF-320A ) To measure and calculate the number of elements of silicon and aluminum.

(5) BET Specific Surface Area The specific surface area of zeolite and activated carbon is measured using NOVA2200e manufactured by Yuasa Ionics Co., Ltd. according to the BET multipoint method specified in JIS R 1626-1996. As a sample, 100 mg is collected, vacuum degassed at 100 ° C. for 4 hours, N2 is used as an adsorbent, and the sample is measured by a constant volume method.

(6) Average pore diameter The average pore diameter (D) is calculated from the specific surface area (S) and pore volume (V) obtained during the BET specific surface area measurement, assuming that the shape of the zeolite pores is cylindrical. To do.

(7) Content of water-soluble acid hydrazide compound The weight of the gas adsorbent after impregnating the Y-zeolite in a solution in which the water-soluble acid hydrazide compound is dispersed or dissolved and drying the Y-zeolite, and the above. It is calculated from the difference from the weight of the Y-type zeolite before the impregnation treatment.

(8) Content of thermoplastic resin that can be a gas adsorbent or a binder After spraying a mixed powder obtained by mixing and stirring a gas adsorbent and a thermoplastic resin on a non-woven fabric, another non-woven fabric is further superposed and heat-pressed to be integrated. The total grain size is measured, and the value obtained by subtracting the grain size of the two non-woven fabrics from the total grain size is multiplied by the charge amount ratio of the gas adsorbent and the thermoplastic resin to obtain the gas adsorbent and thermoplasticity for the entire deodorant fiber sheet. Calculate the resin content.

(9) Pressure loss (Pa)
A flat deodorant fiber sheet is set in a holder with an effective frontage area of 0.1 m ² , air is passed in the vertical direction at a surface wind speed of 6.5 m / min, and the pressure difference between the upstream and downstream of the filter is measured by the digital manometer MA2 manufactured by MODUS. Measure with a -04P differential pressure gauge. The measurement is performed by arbitrarily sampling 5 points from one sample, and the average value is taken as the pressure loss of the deodorant fiber sheet.

(10) Dynamic adsorption performance and desorption suppression performance of low boiling point aldehyde Acetaldehyde was used as the low boiling point aldehydes.

A 12 cm square size flat plate deodorant fiber sheet is attached to a 10 cm square size experimental duct, and air having a temperature of 23 ° C. and a humidity of 50% RH is blown to the duct at a rate of 0.2 m / sec. From the upstream side, acetaldehyde was added to an upstream concentration of 10 ppm using a standard gas cylinder, air was sampled on the upstream and downstream sides of the deodorant fiber sheet, and each was sampled using an infrared absorption continuous monitor. The acetaldehyde concentration is measured over time, and the removal efficiency is calculated by the following formula.
Acetaldehyde removal efficiency (%) = [(C _0- C) / C ₀ ] x 100
C ₀ : Acetaldehyde concentration on the upstream side (= 10 ppm)
C: Downstream acetaldehyde concentration (ppm)
The removal efficiency 100 seconds after the start of addition of acetaldehyde is defined as the initial removal efficiency, and the removal efficiency after 100 seconds is measured over time. Further, the adsorption amount until the difference between the concentration on the upstream side and the concentration on the downstream side becomes 5% is evaluated as the adsorption capacity.

Furthermore, for the deodorant fiber sheet that was continuously distributed and the concentration was measured until the removal rate reached 5%, clean air containing no acetaldehyde at a temperature of 23 ° C. and a humidity of 50% RH was introduced at a rate of 0.2 m / sec. The odor intensity of the blown air downstream of the blown and deodorant fiber sheet is judged by a monitor of 5 people by a 6-step odor judgment method using the judgment criteria shown in Table 4, and the arithmetic of the judgment results of 5 people. The average value is used as an index for acetaldehyde desorption evaluation. It can be said that the smaller the arithmetic mean, the more highly suppressed the secondary odor of the deodorant fiber sheet.

(11) Dynamic adsorption performance and desorption suppression performance of low-polarity gas Toluene gas was used as the low-polarity gas.
A flat plate-shaped deodorant fiber sheet pretreated in a drying chamber for 2 hours at 100 ° C. was attached to an experimental column, and air at a temperature of 23 ° C. and a humidity of 50% RH was applied to the column at a rate of 0.2 m / sec. Blow. Further, from the upstream side, toluene is volatilized by a permeator and added to an upstream concentration of 80 ppm, air is sampled on the upstream side and the downstream side of the deodorant fiber sheet, and an infrared absorption type continuous monitor is used. Each toluene concentration is measured over time, and the removal efficiency is calculated by the following formula.
Toluene removal efficiency (%) = [(C _0- C) / C ₀ ] x 100
C ₀ : Concentration on the upstream side (= 80 ppm)
C: Toluene concentration on the downstream side (ppm)
The removal efficiency 3 minutes after the start of toluene addition was defined as the initial removal efficiency, and the initial removal efficiency was compared. The removal efficiency after 3 minutes is measured over time. Further, the adsorption amount until the difference between the concentration on the upstream side and the concentration on the downstream side becomes 5% is evaluated as the adsorption capacity.

Furthermore, for the deodorant fiber sheet that was continuously distributed and the concentration was measured until the removal rate reached 5%, clean air containing no toluene at a temperature of 23 ° C. and a humidity of 50% RH was introduced at a rate of 0.2 m / sec. Blow air and measure the gas concentration on the sample outlet side with an infrared absorptive continuous monitor. Since the secondary odor phenomenon is not the total volume of desorption, but whether the maximum peak value exhaled instantaneously exceeds the odor threshold is important, the evaluation of the desorption suppression performance is a test of this desorption suppression performance. The maximum gas concentration measured at times is used, and it is evaluated that the smaller the maximum gas concentration, the better the desorption suppression performance of the gas adsorbent.

In addition, the odor intensity of the blown air downstream of the sample is determined by five monitors by a six-step odor determination method using the determination criteria shown below.
5: Strong odor 4: Strong odor 3: Easy odor 2: Weak odor that you can understand what odor 1: Finally odor 0: Odorless The arithmetic mean value of the judgment results of 5 people is used as an index for toluene desorption evaluation. To do. It can be said that the smaller the arithmetic mean, the more highly suppressed the secondary odor of the deodorant fiber sheet.

(12) Desorption Judgment Comprehensive judgment on desorption odor is made from the arithmetic mean value of acetaldehyde gas and toluene gas by the 6-step odor judgment method and the maximum concentration of toluene desorption. The comprehensive judgment was made in four stages of A (particularly excellent), B (excellent), C (having improvement), and D (undesirable). The judgment criteria are as follows.
A: When the maximum concentration of toluene desorbed is 1.5 ppm or less and the 6-step odor determination method is 0.6 or less for both acetaldehyde gas and toluene gas.
B: When the maximum concentration of toluene desorbed is in the range of 1.5 ppm or more and 2.0 ppm or less, and the 6-step odor determination method is 0.6 or more and 1.0 or less for both acetaldehyde gas and toluene gas. ,
C: The maximum concentration of toluene desorbed is in the range of more than 2.0 ppm to 5.0 ppm or less, and the 6-step odor determination method is more than 1.0 and 2.5 or less for both acetaldehyde gas and toluene gas. If,
D: When the maximum concentration of toluene desorbed exceeds 5.0 ppm, and the maximum concentration of toluene desorbed exceeds 2.5 by the 6-step odor determination method for either acetaldehyde gas or toluene gas.
(13) Preparation of the gas adsorbent of the present invention and the gas adsorbent for comparison i. Preparation of gas adsorbent A (zeolite)
First, sodium aluminate and sodium silicate were mixed to obtain a mixture, and then the mixture was heated at 100 ° C. to obtain zeolite. Next, the zeolite was treated with an ammonium nitrate solution at 110 ° C., and the zeolite was further calcined with superheated steam at 750 ° C. The obtained zeolite was a proton-type Y-type zeolite. The molar ratio of SiO ₂ / Al ₂ O ₃ measured by fluorescent X-ray spectroscopy of this zeolite was 5.4, and the specific surface area measured by the nitrogen adsorption / desorption method was 690 m ² / g. Then, using this zeolite as a raw material, alumina sol was used as a binder, and a zeolite granulated to an average particle size of 230 μm by a high-speed mixer method was used. The specific surface area of the zeolite after granulation was 600 m ² / g, and the average pore diameter was 17.0 Å. The proton-type Y-zeolite refers to a Y-type zeolite whose cation exchange site is a proton (H ⁺ ).

(Water-soluble acid hydrazide compound)
Adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) having a solubility in water of 8.0% was used.

(Zeolite A)
An aqueous solution in which 8.0% by mass of the adipic acid dihydrazide was completely dissolved in 100.0% by mass of pure water was prepared. Then, the aqueous solution was sprayed onto 40.0% by mass of the granulated zeolite and adhered, and then dried at 110 ° C. for 5 hours to obtain a gas adsorbent A.

ii. Preparation of gas adsorbent B (zeolite)
First, sodium aluminate and sodium silicate were mixed to obtain a mixture, and then the mixture was heated at 100 ° C. to obtain zeolite. Next, the zeolite was treated with an ammonium nitrate solution at 110 ° C., and the zeolite was further calcined with superheated steam at 750 ° C. The obtained zeolite was a proton-type Y-type zeolite. The molar ratio of SiO ₂ / Al ₂ O ₃ measured by fluorescent X-ray spectroscopy of this zeolite was 7.2, and the specific surface area measured by the nitrogen adsorption / desorption method was 650 m ² / g. Then, using this zeolite as a raw material, alumina sol was used as a binder, and a zeolite granulated to an average particle size of 230 μm by a high-speed mixer method was used. The specific surface area of the zeolite after granulation was 580 m ² / g, and the average pore diameter was 16.5 Å.

(Water-soluble acid hydrazide compound)
Adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) having a solubility in water of 8.0% was used.

(Gas adsorbent B)
An aqueous solution in which 8.0% by mass of the adipic acid dihydrazide was completely dissolved in 100.0% by mass of pure water was prepared. Then, the aqueous solution was sprayed onto 40.0% by mass of the granulated zeolite and adhered, and then dried at 110 ° C. for 5 hours to obtain a gas adsorbent B.

iii. Preparation of gas adsorbent C (zeolite)
First, sodium aluminate and sodium silicate were mixed to obtain a mixture, and then the mixture was heated at 100 ° C. to obtain zeolite. Next, the zeolite was treated with an ammonium nitrate solution at 110 ° C., and the zeolite was further calcined with superheated steam at 750 ° C. The obtained zeolite was a proton-type Y-type zeolite. The molar ratio of SiO ₂ / Al ₂ O ₃ measured by fluorescent X-ray spectroscopy of this zeolite was 5.4, and the specific surface area measured by the nitrogen adsorption / desorption method was 690 m ² / g. Then, using this zeolite as a raw material, alumina sol was used as a binder, and a zeolite granulated to an average particle size of 230 μm by a high-speed mixer method was used. The specific surface area of the zeolite after granulation was 600 m ² / g, and the average pore diameter was 17.0 Å.

(Water-soluble acid hydrazide compound)
Dihydrazide succinate (manufactured by Japan Finechem Company, Inc.) having a solubility in water of 27.3% was used.

(Gas adsorbent C)
An aqueous solution was prepared in which 20.0% by mass of dihydrazide succinate was completely dissolved in 100.0% by mass of pure water. Then, the aqueous solution was sprayed onto 40.0% by mass of the granulated zeolite and adhered, and then dried at 110 ° C. for 5 hours to obtain a gas adsorbent C.

iv. Preparation of gas adsorbent D (zeolite)
Using commercially available ZSM-5 type zeolite with a molar ratio of SiO ₂ / Al ₂ O _{3 of} 38.0 and a specific surface area of 340 m ² / g as a raw material, and using alumina sol as a binder, averaged by a high-speed mixer method. Zeolites granulated to a particle size of 230 μm were used. The specific surface area of the zeolite after granulation was 300 m ² / g, and the average pore diameter was 18.4 Å.

(Water-soluble acid hydrazide compound)
Adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) having a solubility in water of 8.0% was used.

(Gas adsorbent D)
An aqueous solution in which 8.0% by mass of the adipic acid dihydrazide was completely dissolved in 100.0% by mass of pure water was prepared. Then, the aqueous solution was sprayed onto 40.0% by mass of the granulated zeolite and adhered, and then dried at 110 ° C. for 5 hours to obtain a gas adsorbent D.

v. Preparation of gas adsorbent E (zeolite)
First, sodium aluminate and sodium silicate were mixed to obtain a mixture, and then the mixture was heated at 100 ° C. to obtain zeolite. Next, the zeolite was treated with an ammonium nitrate solution at 110 ° C., and the zeolite was further calcined with superheated steam at 750 ° C. The obtained zeolite was a proton-type Y-type zeolite. The molar ratio of SiO ₂ / Al ₂ O ₃ measured by fluorescent X-ray spectroscopy of this zeolite was 5.4, and the specific surface area measured by the nitrogen adsorption / desorption method was 690 m ² / g.

vi. Preparation of gas adsorbent F (zeolite)
A type zeolite (sodium type A type zeolite) having a molar ratio of SiO ₂ / Al ₂ O ₃ and having an alkali metal ion Na ⁺ as a cation group was used. The A-type zeolite having an alkali metal ion Na ⁺ as a cation group (sodium-type A-type zeolite) refers to an A-type zeolite having a cation exchange site of Na ⁺ .

Preparation of vii gas adsorbent G (zeolite)
SiO ₂ / _Al 2 _{O 3} molar ratio of 25.0, was used Y-type zeolite having an ammonium ion _NH ^{4 +} is a specific surface area of 680 m ² / g. Note that the Y-type zeolite having an ammonium ion _NH ^{4 +,} a cation exchange site refers to a Y-type zeolite is a _NH ^{4 +.}

viii. Activated carbon A
A coconut shell activated carbon having an average particle size of 220 μm and a specific surface area of 1100 m ² / g according to the JIS K1474 method was used.

ix. Activated carbon B
(Activated carbon)
A coconut shell activated carbon having an average particle size of 220 μm and a specific surface area of 1200 m ² / g according to the JIS K1474 method was used.

(Adhesive drug)
Adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) having a solubility in water of 8.0% was used.

(Activated carbon B)
An aqueous solution in which 8.0% by mass of the adipic acid dihydrazide was completely dissolved in 100.0% by mass of pure water was prepared. Then, the aqueous solution was sprayed onto the activated carbon in an amount of 40.0% by mass to adhere to the activated carbon, and then dried at 110 ° C. for 5 hours to obtain activated carbon B.

x. Activated carbon C
A coconut shell activated carbon having an average particle size of 220 μm and a specific surface area of 1200 m ² / g according to the JIS K1474 method was used.

xi. Porous silica A
(Inorganic porous body)
Silica gel (manufactured by AGC SI Tech) having an average particle diameter of 200 μm, a specific surface area of 700 m ² / g, and an average pore diameter of 60 Å according to the JIS K1474 method was used.

(Acid hydrazide compound)
Adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) having a solubility in water of 8.0% was used.

(Porous Silica A)
An aqueous solution in which 8.0% by mass of the adipic acid dihydrazide was completely dissolved in 100.0% by mass of pure water was prepared. Then, the aqueous solution was sprayed onto the porous silica in an amount of 40.0% by mass to adhere to the porous silica, and then dried at 110 ° C. for 4 hours to obtain porous silica A.

xii. Porous silica B
(Inorganic porous body)
Silica gel (manufactured by AGC SI Tech) having an average particle size of 200 μm, a specific surface area of 30 m ² / g, and an average pore size of 1000 Å according to the JIS K1474 method was used.

(Acid hydrazide compound)
Adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) having a solubility in water of 8.0% was used.

(Porous Silica B)
An aqueous solution in which 8.0% by mass of the adipic acid dihydrazide was completely dissolved in 100.0% by mass of pure water was prepared. Then, the aqueous solution was sprayed onto the porous silica in an amount of 40.0% by mass to adhere to the porous silica, and then dried at 110 ° C. for 4 hours to obtain porous silica B.

(14) Example, Comparative Example [Example 1]
(Non-woven fabric a)
A fiber aggregate having a basis weight of 30 g / m ² composed of polyester fibers and vinylon fibers was produced by a wet papermaking method. The fiber aggregate was impregnated with a dispersion of a styrene acrylic polymer and melamine phosphate as a flame retardant, and then dried and heat-treated to prepare a non-woven fabric a having a texture of 50 g / m ² and a thickness of 0.42 mm.

(Non-woven fabric b)
As the thermoplastic resin, a polypropylene resin having a melting point of 163 ° C. was used, and a polypropylene resin composition to which a charge stabilizer was added was used. Melt blow nonwoven fabrics were manufactured using a device consisting of an extruder and gear pump, a melt blow cap, a compressed air generator and an air heater, a collection conveyor, and a winder.

After adjusting the injection flow rate so that the melt blow fiber flow is tilted toward the sheet traveling direction to collect the melt blow fiber flow to form a sheet, electret processing is performed by the pure water suction method, and the grain size is 30 g / m ² , average. A non-woven fabric b having a fiber diameter of 6.2 μm and a thickness of 0.20 mm was obtained.

(Deodorant fiber sheet)
The gas adsorbent A and low density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) as a hot melt adhesive were weighed at a mass ratio of 70/30 (zeolite / low density polyethylene). After stirring with a shaker, the non-woven fabric a was uniformly sprayed on the non-woven fabric a so as to have a total mass ratio of 50 g / m ^{2. With the} hot melt adhesive melted in a drying oven at 150 ° C. The deodorant fiber sheet A was prepared in this manner. Table 1 shows the composition of the gas adsorbent. Table 3 shows the physical properties and performance of the deodorant fiber sheet.

[Example 2]
(Deodorant fiber sheet)
The gas adsorbent B and low density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) as a hot melt adhesive were used as 73.7 / 26.3 (gas adsorbent B / low density polyethylene). Weighed by mass ratio, stirred with a shaker, and then uniformly sprayed on the non-woven fabric a so as to have a total amount of 95 g / m ^{2. The} hot melt adhesive was melted in a drying oven at 150 ° C. A deodorant fiber sheet B was prepared by covering with a non-woven fabric b and hot pressing. Table 1 shows the composition of the gas adsorbent and the like. Table 3 shows the physical properties and performance of the deodorant fiber sheet.

[Example 3]
(Deodorant fiber sheet)
A gas adsorbent containing the gas adsorbent A and activated carbon A, and low-density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999))) as a hot melt adhesive were added to 55.6 / 15.9 / 28. Weighed at a mass ratio of .6 (gas adsorbent A / activated carbon A / low density polyethylene), stirred with a shaker, and then uniformly sprayed on the non-woven fabric a so as to have a total amount of 63 g / m ^2. A deodorant fiber sheet C was prepared by covering the non-woven fabric b on the melted hot melt adhesive in a drying oven at ° C. and hot pressing. Table 1 shows the composition of the gas adsorbent. Table 3 shows the physical properties and performance of the fiber sheet.

[Example 4]
(Deodorant fiber sheet)
The gas adsorbent A and activated carbon B and low-density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) as a hot melt adhesive were used as 55.6 / 15.9 / 28.6 (gas adsorbent). Weighed by the mass ratio of A / activated carbon B / low density polyethylene), stirred with a shaker, and then uniformly sprayed on the non-woven fabric a so as to have a total amount of 63 g / m ² , hot in a drying oven at 150 ° C. A deodorant fiber sheet D was prepared by covering the non-woven fabric b with the melt adhesive melted and heat-pressing it. Table 1 shows the constitution and the like of the gas adsorbent. Physical properties and performance of the deodorant fiber sheet. Is shown in Table 3.

[Example 5]
(Deodorant fiber sheet)
By impregnating the non-woven fabric a in an aqueous solution in which the gas adsorbent E, adipic acid dihydrazide, and a styrene acrylic binder are uniformly dispersed in pure water so as to have a mass ratio of 43.5 / 21.7 / 34.8, and then drying. A non-woven fabric sheet c having a grain size of 73 g / m ² was obtained. Low-density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) was uniformly sprayed on the non-woven fabric c so as to have a concentration of 7 g / m ^{2. The} hot melt adhesive was melted in a drying oven at 130 ° C. A deodorant fiber sheet E was prepared by covering it with a non-woven fabric b and hot-pressing it. Table 1 shows the composition of the gas adsorbent and the like. Table 3 shows the physical properties and performance of the deodorant fiber sheet. ..

[Comparative Example 1]
(Deodorant fiber sheet)
The activated carbon B and low density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) as a hot melt adhesive are mixed at a mass ratio of 70.0 / 30.0 (activated carbon B / low density polyethylene). After weighing and stirring with a shaker, the non-woven fabric b was uniformly sprayed on the non-woven fabric a so as to have a total mass of 50 g / m ^{2. With the} hot melt adhesive melted in a drying oven at 150 ° C. A deodorant fiber sheet F was prepared by cover heat pressing. Table 2 shows the composition of the gas adsorbent. Table 3 shows the physical properties and performance of the deodorant fiber sheet.

[Comparative Example 2]
(Deodorant fiber sheet)
The activated carbon C and low density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) as a hot melt adhesive are mixed at a mass ratio of 70.0 / 30.0 (activated carbon C / low density polyethylene). After weighing and stirring with a shaker, the non-woven fabric b was uniformly sprayed on the non-woven fabric a so as to have a total mass of 265 g / m ^{2. With the} hot melt adhesive melted in a drying oven at 150 ° C. A deodorant fiber sheet G was prepared by cover heat pressing. Table 2 shows the composition of the gas adsorbent. Table 3 shows the physical properties and performance of the deodorant fiber sheet.

[Comparative Example 3]
(Deodorant fiber sheet)
Mass ratio of the porous silica A and low density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) 70.0 / 30.0 (porous silica A / low density polyethylene) as a hot melt adhesive. Weighed according to the ratio, stirred with a shaker, and then uniformly sprayed on the non-woven fabric a so as to have a total amount of 50 g / m ^{2. From} above, in a state where the hot melt adhesive was melted in a drying oven at 150 ° C. A deodorant fiber sheet H was prepared by covering with a non-woven fabric b and hot pressing. Table 2 shows the composition of the gas adsorbent and the like. Table 3 shows the physical properties and performance of the deodorant fiber sheet.

[Comparative Example 4]
(Deodorant fiber sheet)
Mass ratio of the porous silica B and low density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) 70.0 / 30.0 (porous silica B / low density polyethylene) as a hot melt adhesive. Weighed according to the ratio, stirred with a shaker, and then uniformly sprayed on the non-woven fabric a so as to have a total amount of 50 g / m ^{2. From} above, in a state where the hot melt adhesive was melted in a drying oven at 150 ° C. A deodorant fiber sheet I was prepared by covering with a non-woven fabric b and hot pressing. Table 2 shows the composition of the gas adsorbent and the like. Table 3 shows the physical properties and performance of the deodorant fiber sheet.

[Comparative Example 5]
(Deodorant fiber sheet)
55.6 / 15.9 / 28.6 of the gas adsorbent containing the porous silica A and activated carbon C and low density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999))) as a hot melt adhesive. It was weighed by the mass ratio of (porous silica A / activated carbon C / low density polyethylene), stirred with a shaker, and then uniformly sprayed on the non-woven fabric a so as to have a total amount of 63 g / m ² . A deodorant fiber sheet J was prepared by covering the non-woven fabric b with the non-woven fabric b in a state where the hot melt adhesive was melted in a drying oven and hot pressing. Table 2 shows the composition of the gas adsorbent and the like. The physical properties and performance of the above are shown in Table 3.

[Comparative Example 6]
(Deodorant fiber sheet)
The gas adsorbent D and low density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) as a hot melt adhesive were mixed with 70.0 / 30.0 (gas adsorbent D / low density polyethylene). Weighed by mass ratio, stirred with a shaker, and then uniformly sprayed on the non-woven fabric a so as to have a total amount of 50 g / m ^{2. The} hot melt adhesive was melted in a drying oven at 150 ° C. A deodorant fiber sheet K was prepared by covering with a non-woven fabric b and hot pressing. Table 2 shows the composition of the gas adsorbent and the like. Table 3 shows the physical properties and performance of the deodorant fiber sheet.

[Comparative Example 7]
(Deodorant fiber sheet)
The non-woven fabric a is impregnated in an aqueous solution in which the gas adsorbent F, adipic acid dihydrazide, and a styrene acrylic binder are uniformly dispersed in pure water so as to have a mass ratio of 43.5 / 21.7 / 34.8, and then dried. A non-woven fabric sheet d having a grain size of 73 g / m ² was obtained. Low-density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) was uniformly sprayed on the non-woven fabric d so as to have a concentration of 7 g / m ^{2. The} hot melt adhesive was melted in a drying oven at 130 ° C. A deodorant fiber sheet L was prepared by covering it with a non-woven fabric b and hot-pressing it. Table 2 shows the composition of the gas adsorbent and the like. Table 3 shows the physical properties and performance of the deodorant fiber sheet. ..

[Comparative Example 8]
(Deodorant fiber sheet)
By impregnating the non-woven fabric a in an aqueous solution in which the gas adsorbent G, adipic acid dihydrazide, and a styrene acrylic binder are uniformly dispersed in pure water so as to have a mass ratio of 43.5 / 21.7 / 34.8, and then drying. A non-woven fabric sheet e having a grain size of 73 g / m ² was obtained. Low-density polyethylene (melting point 98 ° C., MI 200 g / 10 min (JIS K7210 (1999)) was uniformly sprayed on the non-woven fabric e so as to have a concentration of 7 g / m ^{2. The} hot melt adhesive was melted in a drying oven at 130 ° C. A deodorant fiber sheet M was prepared by covering it with a non-woven fabric b and hot-pressing it. Table 2 shows the composition of the gas adsorbent and the like. Table 3 shows the physical properties and performance of the deodorant fiber sheet. ..

(15) Summary of Examples The gas adsorbents of Examples 1 and 2 had a SiO ₂ / Al ₂ O ₃ molar ratio of 2 or more and 20 or less to which adipic acid dihydrazide was attached, and had a Y-type zeolite. Compared with the gas adsorbent of Comparative Example 1 using activated carbon, the initial removal efficiency and adsorption capacity of acetaldehyde, which is a representative component of low boiling point aldehydes, were excellent. In the desorption odor evaluation after adsorption saturation, both acetaldehyde gas and toluene gas were 1.0 or less, which was a result that almost no odor was emitted.

Further, Examples 3 and 4 contain a smaller amount of activated carbon. The effect of zeolite with adipic acid dihydrazide attached was excellent in acetaldehyde removal performance, and the combined effect with activated carbon gave even better results in the deodorization odor evaluation after adsorption saturation of toluene and acetaldehyde. In Example 4, since adipic acid dihydrazide is attached to the activated carbon, the effect of improving the deodorizing odor of acetaldehyde is remarkable.

In Example 5, a fine powdery zeolite having a particle size of 5.0 μm is fixed to a non-woven fabric with a binder. However, as in Examples 1 and 2, the acetaldehyde removal performance is excellent, and the deodorized odor after adsorption saturation is evaluated. In the above, both acetaldehyde gas and toluene gas were 1.0 or less, which was a good result with almost no odor.

On the other hand, when only activated carbon was used as the gas adsorbent, the acetaldehyde removal performance was not at a satisfactory level as in Comparative Example 1. As shown in Comparative Example 2, it is possible to improve the acetaldehyde removal performance by increasing the amount of activated carbon, but as the amount of the gas adsorbent increases, the pressure loss of the deodorant fiber sheet increases and the thickness increases. As a result, the pressure loss of the air filter unit also increased significantly. By using a larger amount of activated carbon, acetaldehyde and toluene are adsorbed and concentrated by physical adsorption, and due to environmental factors such as temperature and humidity changes, the concentrated odorous components are released at once, resulting in the maximum concentration of toluene desorbed. Increased to 18.2 ppm, which was 4.0 even in the 6-step odor determination method, and the result was that the odor component, which was not a problem at the original concentration, was recognized as a bad odor.

Further, in Comparative Example 3, by adhering adipic acid dihydrazide to the porous silica, the acetaldehyde removal performance is excellent even with a small amount of gas adsorbent, but toluene is physically adsorbed on the mesopores peculiar to silica, so that toluene is obtained. The maximum desorption concentration increased to 5.8 ppm, and it was 3.0 even in the 6-step odor determination method, and the result was that the odorous component, which was not a problem at the original existing concentration, was recognized as a bad odor.

When porous silica was used as the gas adsorbent, the desorption performance was improved by adjusting the pore diameter of the mesopores as shown in Comparative Example 4, but the acetaldehyde removal performance was significantly reduced. As shown in Comparative Example 5, the desorption performance tends to be improved by mixing with activated carbon, but the result of the 6-step odor determination method of acetaldehyde exceeds 2.0, and the desorption suppression is still performed. It was a level that needed improvement.

Further, as the gas adsorbent of Comparative Example 6, by using a zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 38.0, the amount of physical adsorption of toluene increases, and the maximum desorption concentration after adsorption saturation increases. However, at 9.3 ppm, the odorous component, which was not a problem at the original concentration, was recognized as a foul odor.

In Comparative Example 7, type A zeolite is used, but since the pore diameter is small, it is difficult for the water-soluble acid hydrazide compound to enter the pores, and acetaldehyde is difficult to enter the pores. Sufficient performance was not obtained for acetaldehyde removal.

In Comparative Example 8, Y-type zeolite was used, but since the SiO ₂ / Al ₂ O ₃ molar ratio was 25.0 and the hydrophobicity was strong, the amount of physical adsorption of toluene increased and the maximum desorption concentration increased. Since the cation exchange site in the crystal structure is ammonium ion, sufficient performance for acetaldehyde removal was not obtained.

The gas adsorbent, deodorant fiber sheet and air filter according to the present invention have excellent adsorption performance of low boiling point aldehydes in VOC components, and are derived from gas adsorbents of low boiling point aldehydes and low polar gases generated from the passenger compartment. Since the amount of desorption is small, it is particularly preferably used as an air filter for purifying the air in the passenger compartment of an automobile or a railroad vehicle.

Claims (8)

Contains proton-type Y-zeolite and water-soluble acid hydrazide compound,
The proton-type Y-zeolite contains SiO ₂ and Al ₂ O _3, and contains
A gas adsorbent having a molar ratio of SiO ₂ to Al ₂ O ₃ (molar containing SiO ₂ / mole containing Al ₂ O ₃ ) of 2 or more and 20 or less in the proton-type Y-zeolite. The gas adsorbent according to claim 1, further comprising activated carbon. The gas adsorbent according to claim 2, wherein the activated carbon has a specific surface area of 900 to 1300 m ² / g. The mass ratio of the activated carbon to the proton-type Y-zeolite and the water-soluble acid hydrazide compound (sum of the mass of the activated carbon / the mass of the proton-type Y-zeolite and the water-soluble acid hydrazide compound) is 0.05 to The gas adsorbent according to claim 2 or 3, which is 0.50. A deodorant fiber sheet having the gas adsorbent according to any one of claims 1 to 4. The deodorant fiber sheet according to claim 5, wherein the content of the gas adsorbent per unit area is 10 to 100 g / m ² . An air filter unit comprising the deodorant fiber sheet according to claim 5 or 6. After mixing sodium aluminate and sodium silicate to obtain a mixture, the mixture is heated at 90 to 120 ° C. to obtain zeolite.
A step of treating the zeolite with an ammonium nitrate solution at 100 to 120 ° C.
A step of calcining the zeolite with superheated steam at 500 to 800 ° C.
A method for producing a gas adsorbent, which comprises a step of adhering a water-soluble acid hydrazide compound to the zeolite in this order.