WO2019151283A1

WO2019151283A1 - Gas adsorbent, deodorant fiber sheet, and method for preparing gas adsorbent

Info

Publication number: WO2019151283A1
Application number: PCT/JP2019/003069
Authority: WO
Inventors: 三好賢吾; 浅田康裕; 八並裕治
Original assignee: 東レ株式会社
Priority date: 2018-02-02
Filing date: 2019-01-30
Publication date: 2019-08-08
Also published as: CN111683745B; CN111683745A; JPWO2019151283A1; JP7188383B2

Abstract

The purpose of the present invention is to provide a gas adsorbent which has excellent adsorption performance for low-boiling point aldehydes and also has excellent performance for suppressing the desorption of low-boiling point aldehydes and low-polar gases from a gas adsorbent, once the low-boiling point aldehydes and the low-polar gases have been adsorbed onto the gas adsorbent. This purpose is achieved by providing a gas adsorbent containing: a proton-type Y zeolite; and a water-soluble acid hydrazide compound, wherein the proton-type Y zeolite contains SiO₂ and Al₂O₃, and the molar ratio of SiO₂ to Al₂O₃ contained (mole of SiO₂ contained/mole of Al₂O₃ contained) therein is 2-20.

Description

Gas adsorbent, deodorant fiber sheet, and method for producing gas adsorbent

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

2. Description of the Related Art In recent years, there has been a demand for the ability to clean air by removing volatile organic compounds (VOC) in addition to dust present in the air by using a filter medium that is a deodorizing fiber sheet, due to the increasing desire to improve the living environment. . Particularly in vehicles such as automobiles, since there are many parts using binders and paints in a narrow space, VOC tends to exist at a high concentration, and efficient removal of VOC by a filter medium is required.

Recently, development has been promoted to reduce the amount of VOC generated from automobile parts, and the amount of organic solvents such as toluene and xylene has been reduced below the guidelines set by the Ministry of Health, Labor and Welfare. Low-boiling aldehydes such as formaldehyde and acetaldehyde are difficult to counter by the source, and a filter medium capable of removing low-boiling aldehydes is required.

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

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

In addition, Patent Document 2 discloses an adsorbent obtained by adding acid hydrazide to A-type zeolite or X-type zeolite. Patent Document 3 discloses an adsorbent obtained by adding an amine compound to zeolite.

JP 2007-167632 A JP 2011-83756 A Japanese Patent Laid-Open No. 08-280781

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

The present invention is intended to solve the above-mentioned problems, and is excellent in the adsorption performance of low-boiling aldehydes under dynamic conditions where air such as an air filter is circulating, and once adsorbed by the adsorbent. Another object of the present invention is to provide a gas adsorbent having excellent performance for suppressing the desorption of low-boiling aldehydes and low polar gases from the adsorbent.

The present invention for solving the above-described problems is characterized by taking one of the following configurations.
(1) A proton type Y zeolite and a water-soluble acid hydrazide compound are contained, and the proton type Y zeolite contains SiO ₂ and Al ₂ O ₃ , and SiO in the proton type Y zeolite Gas adsorbent in which the content molar ratio of ₂ to Al ₂ O ₃ (the content mole of SiO ₂ / the content mole of Al ₂ O ₃ ) is 2 or more and 20 or less.
(2) The gas adsorbent according to (1), further comprising activated carbon.
(3) The gas adsorbent according to (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 mass ratio of the activated carbon to the Y-type zeolite (the mass of the activated carbon / the mass of the Y-type zeolite) is 0.05 to 0.50. .
(5) A deodorizing fiber sheet comprising the gas adsorbent according to any one of (1) to (4).
(6) The deodorized fiber sheet according to (5), wherein the content of the gas adsorbent per unit area is 10 to 100 g / m ² .
(7) An air filter unit comprising the deodorizing 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 zeolite, and the zeolite is treated with an ammonium nitrate solution at 100 to 120 ° C. A method for producing a gas adsorbent comprising a step, a step of calcining the zeolite with superheated steam at 500 to 800 ° C., and a step of attaching a water-soluble acid hydrazide compound to the zeolite in this order.

Excellent adsorption performance of low-boiling aldehydes under dynamic conditions where air such as an air filter is circulating, and gas adsorption of low-boiling aldehydes and low-polarity gases once adsorbed to the gas adsorbent It is possible to provide a gas adsorbent that is excellent in performance of suppressing desorption from the agent.

The gas adsorbent of the present invention contains a proton type Y zeolite (hereinafter sometimes 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 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 ₂ O ₃ -containing mole) is 2 or more and 20 or less. The gas adsorbent is excellent in adsorption performance of low-boiling aldehydes under dynamic conditions where air such as an air filter is circulating (hereinafter sometimes referred to as “dynamic adsorption performance”), and The low-boiling aldehydes and low-polarity gases once adsorbed on the gas adsorbent are excellent in the ability to suppress desorption from the gas adsorbent (hereinafter sometimes referred to as “desorption suppression performance”).

It is important that the zeolite contained in the gas adsorbent of the present invention is Y-type zeolite. Y-type zeolite has a bottleneck-type pore structure with an inlet pore diameter of 7.4 mm. Since this inlet pore diameter is larger than that of the A-type zeolite, it is easy to add a water-soluble acid hydrazide compound, and the amount of addition can be increased. As a result, dynamic adsorption performance can be enhanced. Y type zeolite has a structure with a larger pore inlet than A type zeolite, so it is possible to promote the entry of low-boiling aldehydes to be removed into the zeolite pores, resulting in dynamic adsorption performance. Can be increased. On the other hand, since Y-type zeolite does not have mesopores unlike porous silica, it is possible to inhibit the entry of high-boiling aldehydes and low-polarity gases into the pores, thereby suppressing the amount of accumulation. . As a result, the desorption suppression performance of the gas adsorbent is excellent.

Also, the chemical reaction between low boiling point aldehydes and water-soluble acid hydrazide compounds is a multistage reaction. Acetaldehyde, which is a representative component of low-boiling aldehydes, will be described as an example. The chemical reaction between an acid hydrazide compound and acetaldehyde is a multi-step reaction in which an intermediate product carbinolamine undergoes a reaction of eliminating water. And this multistage reaction has the characteristic that progress is accelerated | stimulated in presence of an acid catalyst. Here, the proton-type Y-type zeolite exhibits a 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 is 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 dealumination.

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 the molar of molar / _Al 2 _{O 3)} is 2 to 20. Proton type Y zeolite zeolite has a three-dimensional framework structure which is a crystalline aluminosilicate. During synthesis, the mixing ratio of the silica raw material and the alumina raw material is adjusted. The composition ratio of silicon and aluminum can be controlled.

Here, in the proton type Y-type zeolite, when the SiO ₂ / Al ₂ O ₃ content molar ratio increases, the ratio of metal cations existing in the crystal lattice decreases. As a result, the affinity for polar substances such as water is weakened, and nonpolar substances are more adsorbed. Therefore, by reducing the SiO ₂ / Al ₂ O ₃ content molar ratio of the proton type Y zeolite as low as 20 or less, the decrease in the hydrophilicity of the proton type Y zeolite is suppressed, and the porous structure is reduced. Since the water-soluble acid hydrazide compound can be adhered to the inner surface of the pores of the Y-type zeolite having, the dynamic adsorption performance of the gas adsorbent of the present invention is excellent.

In addition to the above effects, physical adsorption of non-polar or low-polarity gases to proton type Y-type zeolite can be suppressed. That is, non-polar or low-polarity gases are not easily accumulated in the proton type Y-type zeolite. It is suppressed that a large amount of accumulated non-polar or low-polarity gases, which are likely to be another type of zeolite, is released in some way. That is, the desorption suppression performance of the gas adsorbent of the present invention is excellent.

Also, when the above-mentioned molar ratio is low, the hydrophilicity of the zeolite increases, and water tends to accumulate in the pores of the zeolite. Then, it becomes difficult for aldehyde gas to enter the pores. Therefore, by setting the content molar ratio to 2 or more, even when the air filter equipped with the gas adsorbent of the present invention is used, the low-boiling aldehydes can easily enter the pores of the zeolite, and the gas of the present invention can be 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-type zeolite, the faster the adsorption rate of the low-boiling aldehydes in the gas adsorbent. On the other hand, the proton type Y zeolite is likely to be scattered, and the handleability and workability of the proton type Y zeolite tend to be lowered. Therefore, the average particle diameter of the proton type Y-type zeolite is preferably 0.5 μm or more, and more preferably 1.0 μm or more. In addition, if the average particle size of the proton type Y-type zeolite is large, it may be difficult to produce the proton type Y-type zeolite having such a particle size. The type zeolite tends to break, and conversely, dust tends to be generated. The average particle size of the proton-type Y-type zeolite is preferably 1000.0 μm or less, and more preferably 700.0 μm or less.

The proton type Y zeolite having an average particle size of 100.0 μm or more can be obtained by granulating powdery 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 proton type Y-type zeolite, it is preferable to employ a wet granulation method such as a high speed mixer method or a spray drying method.

The average particle diameter here is calculated by the following method. In accordance with the method described in JIS K1474 (2014), the particle size is measured by the ratio of passing through the openings and expressed as an integrated weight percentage. The particle size having an integrated value of 50% is defined as “average particle size”. However, if the average particle size is about several μm, the sieve may be clogged, so proton type Y 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 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, an effective area increases as a reaction field for the water-soluble acid hydrazide compound supported by the Y-type zeolite. By increasing the area, the reaction rate between the gas adsorbent and the low-boiling aldehydes to be removed is further improved, and the dynamic adsorption performance of the gas adsorbent of the present invention is 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-type zeolite is preferably 1000 m ² / g or less. This is because exceeding this range causes inconvenience 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-type zeolite means the peak diameter obtained by the MP method, and more specifically, it is determined using the adsorption side isotherm obtained by the nitrogen adsorption method at 77 Kelvin (liquid nitrogen temperature). It is done. The range of the average pore size of the proton type Y zeolite is preferably 7.0 to 30.0 mm, more preferably 7.5 to 20.0 mm. Proton Y-type zeolite has a uniform pore diameter peak in the range of 7.0 to 10.0 mm in average pore diameter, but macropores may be formed in the process of producing secondary particles in the granulation process. To the above range.

When the average pore diameter is 7.0 mm or more, the acid hydrazide compound can easily penetrate into the pores of the proton type Y-type zeolite, and the reactivity with low-boiling aldehydes can be enhanced. As a result, the dynamic adsorption performance of the gas adsorbent becomes better. On the other hand, in the gas adsorbent, the Y-type zeolite has an average pore diameter of 30.0 mm or less, which inhibits the entry of high-boiling aldehydes and low polar gases into the pores, which can be a problem of desorption odor, It is possible to suppress the accumulation amount of these gases. As a result, the desorption suppression performance of the gas adsorbent is 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-type zeolite in order to adsorb the low boiling point aldehydes contained in the VOC gas.

Here, water-soluble in the present invention means that 0.5% by mass or more (5 g / L or more) dissolves in 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 carboxylic acid and hydrazine. Further, a nitrogen atom having an unshared electron pair is bonded to the α-position of the hydrazide terminal, thereby significantly improving the nucleophilic reactivity. When this unshared electron pair reacts by nucleophilic attack on the carbonyl carbon atom of the low-boiling aldehydes, and the low-boiling aldehydes are immobilized as hydrazine derivatives, the adsorption ability of the low-boiling aldehydes can be expressed. Conceivable.

Among the low-boiling aldehydes, acetaldehyde has an electron-donating alkyl group at the α-position of the carbonyl carbon, so the carbonyl carbon has low electrophilicity and is difficult to be chemisorbed. 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 chemical adsorption performance for acetaldehyde.

Examples of the water-soluble acid hydrazide compound include those containing at least one 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 in that it has excellent adsorption performance for low-boiling aldehydes. Moreover, it is more preferable to use adipic acid dihydrazide and succinic acid dihydrazide in combination for the purpose of improving the adsorption performance of low-boiling 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-type zeolite. By setting the content of the water-soluble acid hydrazide compound to 0.5 parts by mass or more, the adsorption performance of the low-boiling aldehydes of the gas adsorbent can be further improved, and the dynamic adsorption performance of the gas adsorbent is 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. And by making content of a water-soluble acid hydrazide compound into 20.0 mass parts or less, crystallization of the water-soluble acid hydrazide compound adhering to a Y-type zeolite can be suppressed, and crystallized water-soluble It is possible to prevent the acid hydrazide compound from blocking the pores of the Y-type zeolite. As a result, the dynamic adsorption performance of the low-boiling aldehydes of the gas adsorbent can be improved, and the desorption suppression performance of the gas adsorbent of the present invention can be improved.

The pH of the Y-type zeolite attached with the water-soluble acid hydrazide compound used in the present invention 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 formed from the reaction of the water-soluble acid hydrazide compound by the nucleophilic attack on the carbonyl carbon atom of the low-boiling aldehydes of the lone pair becomes an acidic reaction field. In this case, it becomes easy to dehydrate, and the immobilization reaction of the intermediate to the derivative proceeds sufficiently. For the above reason, the pH is more preferably 7.0 or less. In addition, when the pH is 4.0 or more, the activity of the lone carbon pair of the water-soluble acid hydrazide compound to nucleophilically attack the carbonyl carbon atom of the low-boiling aldehydes becomes higher, and the gas adsorbent Thus, the dynamic adsorption performance of the low-boiling aldehydes is more excellent. The pH was a value obtained by immersing the Y-type zeolite with the acid hydrazide compound attached in pure water at 25 ° C. to 5% by mass, stirring it lightly and leaving it for 10 minutes, and measuring the pH of the liquid with a pH meter. 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 adopt an organic acid that does not generate odor and has low hygroscopicity. Specific examples of the organic acid as described above include adipic acid, sulfanilic acid, malic acid, citric acid and the like, and may be appropriately selected according to the acid hydrazide compound to be used. Among them, adipic acid is preferably employed. be able to. Adipic acid is preferable because it maintains a stable balance of the dispersion and does not cause odor generation or hygroscopicity.

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

Here, examples of the step of attaching a water-soluble acid hydrazide compound to zeolite include the following.
A method in which a water-soluble acid hydrazide compound is attached to a Y-type zeolite by introducing and dispersing the Y-type zeolite in an aqueous solution in which a water-soluble acid hydrazide compound is dissolved.
A method in which an aqueous solution in which a water-soluble acid hydrazide compound is dissolved in a solvent is sprayed and applied to a Y-type zeolite, and then the Y-type zeolite is dried.

As the solvent for the latter method, an appropriate solvent can be selected in consideration of the characteristics and workability of the water-soluble acid hydrazide compound. Among 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 directly formed on the fiber sheet by drying the 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.

In addition, the gas adsorbent of the present invention preferably has activated carbon in addition to the water-soluble acid hydrazide compound and proton type Y-type zeolite. The gas adsorbent of the present invention further suppresses the desorption of the once adsorbed VOC gas from the gas adsorbent and further suppresses the generation of secondary odor in the air filter using this gas adsorbent. It can be done. And, when used in automotive applications where the wind pressure of the airflow passing through the air filter tends to be strong, secondary odor due to odor gas desorption from the deodorant fiber sheet is noticeably generated. And since the air filter using the gas adsorbent of this invention can suppress a secondary odor, the air filter using the gas adsorbent of this invention can be used suitably for a motor vehicle use.

In the embodiment of the gas adsorbent of the present invention having proton type Y zeolite and activated carbon, the activated carbon is a granular material separate from the 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), the proton type Y zeolite and the activated carbon are partially fixed to each other by an adhesive. It may exist in the state.

Here, the Y-type zeolite to which the water-soluble acid hydrazide compound is adhered is excellent in the adsorption performance of low-boiling aldehydes under dynamic conditions. In addition, even after the amount of chemical adsorption with respect to the low-boiling aldehydes is saturated, the shape of the pores having a uniform pore diameter unique to Y-type zeolite and the moles of SiO ₂ / Al ₂ O ₃ in the Y-type zeolite By setting the ratio to 20.0 or less, it becomes possible to greatly suppress the physical adsorption amount of low-boiling aldehydes and low-polarity gas components, and excellent desorption suppression performance.

However, as long as it has a pore structure, it is difficult to completely eliminate the physical adsorption amount of low polar or non-polar gases on the Y-type zeolite. Aldehydes and low-polar or non-polar gases cause desorption from the gas adsorbent when the temperature and humidity change abruptly, such as when operating an air conditioner, and may be perceived as odor components. Therefore, when the gas adsorbent further has activated carbon, the activated carbon adsorbs low-boiling aldehydes and low polar or nonpolar gases desorbed from the Y-type zeolite, and further suppresses secondary odor generation. (That is, the desorption suppression performance of the gas adsorbent becomes better).

The average particle diameter 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 VOC gas adsorption rate. 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 for the nonwoven fabric at the top of the pleats to be easily broken when processed into an air filter unit, so considering the pleatability of the deodorant fiber sheet, The average particle diameter of the activated carbon is preferably 1000.0 μm or less, and more preferably 600.0 μm or less. The particle diameter of said activated carbon points out the mass mean diameter based on the JISK1474 (2014) activated carbon test method. A desired particle size can be obtained by adjusting the particle size using a normal classifier. However, if the activated carbon becomes a fine powder of about several μm, the sieve may become clogged. In that case, the activated carbon is dispersed in a liquid such as water, and the particle size is reduced using diffracted light or scattered light. Can be measured.

Coconut shell, wood-based, coal-based, pitch-based, and the like are known as raw materials for activated carbon, but palm shell is preferable. The fine pores of coconut shell activated carbon have a large proportion of small pores compared to other raw materials, and the amount of ash that is an impurity is also small. In other words, because the coconut shell activated carbon has small pores, the intermolecular force with the pore walls works effectively against the adsorbed odor molecules, making it difficult to desorb the adsorbed odor molecules, that is, generating secondary odor. There is a feature that can be suppressed.

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 making the specific surface area of activated carbon 900 m < ² > / g or more, it becomes possible to obtain an effective reaction rate as a reaction field with low boiling point aldehydes. Moreover, it becomes possible to suppress the unintentional adsorption | suction of the odor which leads to a secondary odor because the specific surface area of activated carbon shall be 1300 m < ² > / g or less.

The active carbon may carry a drug. Among them, for the purpose of removing low-boiling aldehydes, it is preferable that an amine compound is supported, and among them, a primary amine compound having an amino group is preferable, and an acid hydrazide compound is more preferable.

These amine compounds are adsorbed on activated carbon, or by intercalation 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 amine compounds. be able to.

The amount of the amine compound supported 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. By setting the amount to 0.5 parts by mass or more, the effect of improving the adsorption performance of the low-boiling aldehydes can be obtained. If the amine compound is added excessively, it crystallizes and closes the pores of the activated carbon, which may cause powder falling, so the supported amount is preferably 20.0 parts by mass or less.

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

By setting the content mass ratio to 0.05 or more, when low-boiling aldehydes that Y-type zeolite unintentionally adsorbs by physical adsorption phenomenon are desorbed, these low-boiling aldehydes are placed in the vicinity of Y-type zeolite. By adsorbing the activated carbon present, the desorption suppression performance of the gas adsorbent is further improved. On the other hand, when the content ratio is 0.50 or less, the content ratio of the Y-type zeolite is increased, the adsorption performance of the low-boiling aldehydes is improved, and the dynamic adsorption performance of the gas adsorbent is further improved. In addition to being excellent, once the adsorbed low-boiling aldehydes are less likely to be desorbed, the gas adsorbent has better desorption suppression performance.

A deodorant fiber sheet can be obtained using the gas adsorbent of the present invention. The following can be mentioned as a manufacturing method of such a deodorizing fiber sheet.
(1) A sheeting method obtained by dispersing gas adsorbent particles in water, adhering to a fiber sheet, and then dehydrating.
(2) An airlaid method obtained by dispersing gas adsorbent particles in the air together with fibers when a fiber sheet is formed.
(3) A method in which a gas adsorbent is filled by thermal bonding between two or more layers of nonwoven fabric or woven fabric, net-like material, film, and membrane.
(4) A method in which a gas adsorbent is bonded and supported on a breathable material such as a nonwoven fabric, a woven fabric, or urethane foam 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 nonwoven fabric, a woven fabric, or urethane foam by utilizing the thermoplasticity of a base material or a hot melt adhesive.
(6) A method in which the gas adsorbent is mixed and integrated by kneading the fiber or resin.

Although an appropriate method can be used depending on the application, since the pore blockage of the Y-type zeolite itself can be prevented, the processing method (1), (2), (3), or (5) is performed. It is preferable to use it.

Describing the specific manufacturing method of processing method (1). A method in which a solution 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 the Y-type zeolite and a water-soluble acid hydrazide compound are mixed is used as a base fiber. You may dry after apply | coating to a sheet | seat by a coating process, or after spraying by a spray process.

Alternatively, after fixing the Y-type zeolite and the binder resin on the fiber sheet surface, an aqueous solution mixed with an acid hydrazide compound may be attached by dipping or spraying.

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

In the preparation, it is preferable that the water-soluble acid hydrazide compound and the Y-type zeolite are first dispersed in a solvent, and then the binder resin is dispersed, because this allows more uniform dispersion.

In the deodorizing fiber sheet using the gas adsorbent of the present invention, it is also preferable that a sheet having a different fiber structure is further laminated on a fiber sheet carrying the above Y-type zeolite and a water-soluble acid hydrazide compound. For example, in use as a direct flow filter, if a bulky and coarse nonwoven fabric sheet is laminated on the upstream side, the amount of dust retained is improved and the life can be extended. If a nonwoven fabric sheet made of ultrafine fibers is laminated on the downstream side, high collection efficiency can be achieved.

Furthermore, it is still more preferable if the nonwoven fabric sheet which consists of this ultrafine fiber is electret-treated. By performing the electret treatment, it becomes possible to collect submicron-size and nano-size fine dust that is difficult to remove normally by electrostatic force.

Next, a specific manufacturing method of the processing method (3) will be described. Deodorized fiber sheet can be obtained by integrating thermoplastic resin as a gas adsorbent and binder of the present invention disposed between two layers of nonwoven fabric by thermal bonding. First, mix thoroughly on one nonwoven fabric. 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 a heating method. The other non-woven fabric can be covered with the heat-treated material and pressed to be integrated.

Finally, a hot press method between rolls, which is often used for producing a sheet by hot pressing, or a flat bed laminating method in which the upper and lower sides are sandwiched between flat heat belt conveyors can be used.

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

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

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 moving vehicle or the like.

Further, the content of the thermoplastic resin is preferably 5 to 40% by mass, and more preferably 10 to 35% by mass with respect to the content of the gas adsorbent of the present invention. If it exists in this range, the adhesive force with a nonwoven fabric will improve more, and also the ventilation resistance and deodorizing performance of a deodorant fiber sheet will improve more.

As the fibers forming the above-mentioned nonwoven 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 use. Moreover, you may use combining multiple types.

As the fibers constituting the nonwoven fabric, not only those having a circular cross section but also, for example, those having an irregular cross section and those having a large number of holes and slits on the fiber surface are preferably used. By setting it as such a shape, the surface area of a fiber can be enlarged and in the deodorizing fiber sheet using the gas adsorbent of this invention, the supportability of a gas adsorbent can be improved. The atypical cross-sectional shape herein 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. Such a fiber having an irregular cross-sectional shape can be obtained by spinning using a die having a non-circular hole. Also, fibers having a large number of holes and slits on the fiber surface can be obtained by alloying and spinning two or more types of polymers having different solubility in the solvent, and dissolving and removing the higher solubility polymer with the solvent. Can do.

As a method for producing a nonwoven fabric, a dry method, a wet method, a spunbond method, a thermal bond method, a chemical bond method, a spunlace method (a hydroentanglement method), a spunbond nonwoven fabric, and a melt blown nonwoven fabric can be used. Of the two nonwoven fabrics, at least one nonwoven fabric is preferably a wet nonwoven fabric produced by a papermaking method because the fabric weight and thickness can be made uniform.

The fiber diameter of the fibers constituting the nonwoven fabric may be selected according to the target air permeability and dust collection performance in the application used as the deodorant fiber sheet. The thickness is preferably 1 to 2000 μm. By setting the fiber diameter to 1 μm or more, more preferably 2 μm or more, the gas adsorbent can be prevented from being clogged on the surface of the fiber structure, and the air permeability can be prevented 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 processing air due to a decrease in the fiber surface area.

The basis weight of the nonwoven 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 necessary to maintain the filter structure when air is aerated can be obtained. . Further, by setting the basis weight to 500 g / m ² or less, more preferably 200 g / m ² or less, the gas adsorbent can be uniformly supported up to the inside of the nonwoven fabric, and the deodorized fiber sheet is formed in a pleated shape or a honeycomb shape. Excellent handleability during secondary processing.

The thickness of the nonwoven fabric is preferably 0.10 mm to 0.60 mm. If it is thin, the gas adsorbent particles may jump out and break the nonwoven fabric. If it is thick, the handleability may be deteriorated.

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

Materials that make up the electret-treated non-woven fabric include high electrical properties such as polypropylene, polyethylene, polystyrene, polybutylene terephthalate, polyolefin resins such as polytetrafluoroethylene, aromatic polyester resins such as polyethylene terephthalate, and polycarbonate resins. A material having a resistivity is preferred.

Further, the nonwoven fabric may be configured to include components having ancillary functions such as antibacterial agents, antifungal agents, antiallergen agents, antiviral agents, vitamin agents, flame retardants, and the like. These components may be kneaded into fibers or non-woven fabrics, or may be attached and supported by post-processing. For example, after producing a nonwoven fabric by an arbitrary method, an aqueous solution containing a flame retardant and a resin binder is produced, impregnated and dried, and the nonwoven fabric can be obtained by 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 performance of the low-boiling aldehyde gas adsorption performance. Moreover, by making the content 100 g / m ² or less, it is possible to suppress clogging of the deodorant fiber sheet, and thereby to suppress a decrease in air permeability of the deodorant fiber sheet. it can.

An air filter can be constructed using a deodorant fiber sheet. As the shape of the deodorant fiber sheet in the air filter, it may be used as it is, but a pleat type or a honeycomb type should be adopted in order to put more deodorant fiber sheets in a limited size. Is preferred. When using the pleat type as a direct flow type air filter, and when using the honeycomb type as a parallel flow type filter, increase the contact area of the processing air to improve the collection efficiency and simultaneously reduce the low pressure loss. Can do.

As a method of pleating, there are a reciprocating method, a rotary method, and the like, and any method may be used as long as it is a method of processing into a valley shape. Further, it is desirable to perform a separator process 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 assumed that the temperature rises to around 80 ° C in the vicinity of the air conditioner system in the automobile cabin, an air filter that can maintain a pleated shape at low cost is provided by using a polyolefin resin having a melting point of 90 ° C or higher. It becomes possible.

The distance between the apexes of the folds 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 in close contact with each other and there is a lot of dead space, which makes it impossible to use the sheet efficiently. On the other hand, if it exceeds 30 mm, the deodorized fiber sheet folding area becomes small, so that it becomes impossible to obtain the removal effect corresponding to the thickness of the air filter, which is not preferable.

In addition, it is preferable that the air filter using the gas adsorbent of the present invention is stored in a frame body in terms of air processing efficiency and handleability.

Hereinafter, the present invention will be specifically described with reference to examples. In addition, the evaluation method of each characteristic of the deodorant fiber sheet by a present Example is described below.

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

(2) Weight per unit (g / m ² )
The mass of the measurement sample cut to 25 cm x 25 cm was measured for 4 sheets using a mass meter (FY-300 manufactured by A & D Co., Ltd.), converted from the average value to the mass per 1 m ² , and after the decimal point Round the 2nd place to make the basis weight. In addition, about the fabric weight of a deodorant fiber sheet, it measures by the method similar to said measuring method.

(3) Thickness (mm)
For a measurement sample cut to 10 cm × 10 cm, 10 points are randomly measured using a thickness meter (manufactured by Daiei Kagaku Seiki Co., Ltd., model FS-60DS, probe area 2500 mm ² , measurement load 0.5 KPa), and an average value is calculated. And the thickness. The thickness of the deodorant fiber sheet is also measured by the same method as the above measurement 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 according to the BET multipoint method specified in JIS R 1626-1996 using NOVA2200e manufactured by Yuasa Ionics. 100 mg of a sample is collected, vacuum degassed at 100 ° C. for 4 hours, N2 is used as an adsorbate, and measurement is performed by a constant volume method.

(6) Average pore diameter Assuming that the pore shape of the zeolite is cylindrical, 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. To do.

(7) Content of water-soluble acid hydrazide compound The weight of the gas adsorbent after impregnating Y-type zeolite into a liquid in which the water-soluble acid hydrazide compound is dispersed or dissolved and drying the Y-type zeolite, 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 used as gas adsorbent and binder After spraying mixed powder mixed with gas adsorbent and thermoplastic resin on nonwoven fabric, another nonwoven fabric is layered and heat pressed to integrate. The total basis weight is measured, and the value obtained by subtracting the basis weight of the two nonwoven fabrics from the total basis weight is multiplied by the charged amount ratio of the gas adsorbent and the thermoplastic resin to obtain the gas adsorbent and thermoplastic for the entire deodorant fiber sheet. The resin content is calculated.

(9) Pressure loss (Pa)
Set the flat deodorizing fiber sheet to the effective frontage area 0.1 m ² holder, is passed through the air in a vertical direction at a face velocity 6.5m / min, MODUS Co. digital manometer MA2 the pressure difference of the filter upstream and downstream Measure with a -04P differential pressure gauge. The measurement is performed by sampling 5 points arbitrarily from one specimen, 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 aldehydes Acetaldehyde was used as the low-boiling aldehydes.

A 12 cm square size flat plate-like deodorant fiber sheet is attached to a 10 cm square size experimental duct, and air at a temperature of 23 ° C. and a humidity of 50% RH is blown into the duct at a speed of 0.2 m / sec. Furthermore, from the upstream side, acetaldehyde was added to the upstream concentration of 10 ppm with a standard gas cylinder, air was sampled on the upstream side and the downstream side of the deodorant fiber sheet, and each infrared absorption type continuous monitor was used. 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 ] × 100
C ₀ : upstream acetaldehyde concentration (= 10 ppm)
C: Downstream acetaldehyde concentration (ppm)
The removal efficiency after 100 seconds from the start of addition of acetaldehyde is taken as the initial removal efficiency, and the removal efficiency after 100 seconds is measured over time. Further, the amount of adsorption until the difference between the upstream concentration and the downstream concentration becomes 5% is evaluated as the adsorption capacity.

Furthermore, about the deodorant fiber sheet which continued distribution | circulation and density | concentration measurement until this removal rate became 5%, the clean air of the temperature 23 degreeC and humidity 50% RH which do not contain acetaldehyde is 0.2 m / sec. The odor intensity of the blown air that is blown and downstream of the deodorant fiber sheet is judged by a five-person monitor using a six-step odor judgment method using the judgment criteria shown in Table 4, and the arithmetic result of the judgment results of the five persons The average value is used as an index for evaluating acetaldehyde elimination. In addition, it can be said that the secondary odor of a deodorant fiber sheet is suppressed more highly, so that arithmetic mean is small.

(11) Dynamic adsorption performance and desorption suppression performance of low polarity gas Toluene gas was used as the low polarity gas.
A flat deodorant fiber sheet pretreated by heating in a drying cabinet at 100 ° C. for 2 hours was attached to the experimental column, and air at a temperature of 23 ° C. and humidity of 50% RH was applied to the column at a speed of 0.2 m / sec. Blow. Further, from the upstream side, toluene is volatilized by a permeator and added so that the upstream concentration becomes 80 ppm, air is sampled on the upstream side and downstream side of the deodorant fiber sheet, and an infrared absorption type continuous monitor is used. The respective toluene concentrations are measured over time, and the removal efficiency is calculated by the following formula.
Toluene removal efficiency (%) = [(C ₀ -C) / C ₀ ] × 100
C ₀ : upstream concentration (= 80 ppm)
C: Toluene concentration (ppm) on the downstream side
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 amount of adsorption until the difference between the upstream concentration and the downstream concentration becomes 5% is evaluated as the adsorption capacity.

Furthermore, about the deodorant fiber sheet which continued distribution | circulation and density | concentration measurement until this removal rate became 5%, clean air with a temperature of 23 degreeC and humidity 50% RH which does not contain toluene is 0.2 m / sec. Air is blown, and the gas concentration on the sample outlet side is measured with an infrared absorption type continuous monitor. The secondary odor phenomenon is not the total capacity of desorption, but it is important whether the maximum peak value instantaneously exhaled exceeds the odor threshold. The maximum gas concentration measured occasionally is used, and 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 a five-step monitor using a six-stage odor determination method using the following criteria.
5: Intense odor 4: Strong odor 3: Easy odor 2: Weak odor 1 To do. In addition, it can be said that the secondary odor of a deodorant fiber sheet is suppressed more highly, so that arithmetic mean is small.

(12) Desorption determination A comprehensive determination on desorption odor is performed from the arithmetic average value of the 6-step odor determination method of acetaldehyde gas and toluene gas and the maximum concentration of toluene desorption. The comprehensive judgment was performed in four stages: A (particularly excellent), B (excellent), C (having improvement), and D (not preferred). The judgment criteria are as follows.
A: When the maximum toluene desorption concentration is 1.5 ppm or less and the 6-step odor determination method is 0.6 or less in any of acetaldehyde gas and toluene gas,
B: When the maximum concentration of toluene desorption is in the range of 1.5 ppm to 2.0 ppm, and the 6-step odor determination method is 0.6 to 1.0 in both acetaldehyde gas and toluene gas ,
C: The maximum toluene desorption concentration is in the range of 2.0 ppm to 5.0 ppm, and the 6-step odor determination method is 1.0 to 2.5 in both acetaldehyde gas and toluene gas. If
D: The maximum concentration of toluene desorption is over 5.0 ppm, and in any gas of acetaldehyde gas and toluene gas is over 2.5 in the 6-step odor determination method.
(13) Preparation of gas adsorbent of the present invention and 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 calcined with superheated steam at 750 ° C. The obtained zeolite was a proton type Y zeolite. This zeolite had a SiO ₂ / Al ₂ O ₃ -containing molar ratio measured by fluorescent X-ray spectroscopic analysis of 5.4, and a specific surface area measured by nitrogen adsorption / desorption method was 690 m ² / g. And this zeolite was used as a raw material, alumina sol was used as a binder, and zeolite granulated to an average particle size of 230 μm by a high speed mixer method was used. The specific surface area of the granulated zeolite was 600 m ² / g and the average pore diameter was 17.0 mm. The proton-type Y-type zeolite refers to a Y-type zeolite whose cation exchange site is 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. Thereafter, the aqueous solution was sprayed on and adhered to 40.0% by mass of the zeolite after granulation 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 calcined with superheated steam at 750 ° C. The obtained zeolite was a proton type Y zeolite. This zeolite had a SiO ₂ / Al ₂ O ₃ -containing molar ratio measured by fluorescent X-ray spectroscopic analysis of 7.2, and a specific surface area measured by nitrogen adsorption / desorption method was 650 m ² / g. And this zeolite was used as a raw material, alumina sol was used as a binder, and 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 mm.

(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. Thereafter, the aqueous solution was sprayed on and adhered to 40.0% by mass of the zeolite after granulation 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 calcined with superheated steam at 750 ° C. The obtained zeolite was a proton type Y zeolite. This zeolite had a SiO ₂ / Al ₂ O ₃ -containing molar ratio measured by fluorescent X-ray spectroscopic analysis of 5.4, and a specific surface area measured by nitrogen adsorption / desorption method was 690 m ² / g. And this zeolite was used as a raw material, alumina sol was used as a binder, and zeolite granulated to an average particle size of 230 μm by a high speed mixer method was used. The specific surface area of the granulated zeolite was 600 m ² / g and the average pore diameter was 17.0 mm.

(Water-soluble acid hydrazide compound)
Succinic acid dihydrazide (manufactured by Nippon Finechem Co., Ltd.) having a solubility in water of 27.3% was used.

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

iv. Preparation of gas adsorbent D (Zeolite)
Commercially available ZSM-5 type zeolite with a SiO ₂ / Al ₂ O ₃ content molar ratio of 38.0 and specific surface area of 340 m ² / g is used as a raw material, alumina sol is used as a binder, and averaged by a high speed mixer method. Zeolite granulated to a particle size of 230 μm was used. The specific surface area of the granulated zeolite was 300 m ² / g, and the average pore diameter was 18.4 mm.

(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. Thereafter, the aqueous solution was sprayed onto 40.0% by mass of the granulated zeolite by spraying, 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 calcined with superheated steam at 750 ° C. The obtained zeolite was a proton type Y zeolite. This zeolite had a SiO ₂ / Al ₂ O ₃ -containing molar ratio measured by fluorescent X-ray spectroscopic analysis of 5.4, and a specific surface area measured by 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 SiO ₂ / Al ₂ O ₃ -containing molar ratio of 2.0 and having an alkali metal ion Na ⁺ as a cationic group was used. The A-type zeolite having the alkali metal ion Na ⁺ as a cationic group (sodium-type A-type zeolite) means an A-type zeolite having a cation exchange site of Na ⁺ .

Production of vii gas adsorbent G (Zeolite)
A Y-type zeolite having ammonium ion NH ₄ ⁺ having a SiO ₂ / Al ₂ O ₃ -containing molar ratio of 25.0 and a specific surface area of 680 m ² / g was used. The Y-type zeolite having ammonium ion NH ₄ ⁺ refers to a Y-type zeolite having a cation exchange site of NH ₄ ⁺ .

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

ix. Activated carbon B
(Activated carbon)
Coconut shell activated carbon having an average particle size of 220 μm and a specific surface area of 1200 m ² / g according to 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. Thereafter, the aqueous solution was sprayed on and adhered to 40.0% by mass of the activated carbon and dried at 110 ° C. for 5 hours to obtain activated carbon B.

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

xi. Porous silica A
(Inorganic porous material)
Silica gel (manufactured by AGC S-Tech Co., Ltd.) having an average particle size of 200 μm, a specific surface area of 700 m ² / g and an average pore size of 60 mm according to 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. Thereafter, the aqueous solution was sprayed on and adhered to 40.0% by mass of the porous silica, followed by drying at 110 ° C. for 4 hours to obtain porous silica A.

xii. Porous silica B
(Inorganic porous material)
Silica gel (manufactured by AGC S-Tech Co., Ltd.) having an average particle diameter of 200 μm, a specific surface area of 30 m ² / g and an average pore diameter of 1000 mm according to JIS K1474 method 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. Thereafter, the aqueous solution was sprayed on and adhered to the porous silica by 40.0% by mass, and dried at 110 ° C. for 4 hours to obtain porous silica B.

(14) Examples and Comparative Examples [Example 1]
(Nonwoven fabric a)
A fiber aggregate having a basis weight of 30 g / m ² composed of polyester fiber and vinylon fiber was produced by a wet papermaking method. The fiber assembly was impregnated with a dispersion of a styrene acrylic polymer and melamine phosphate as a flame retardant, and then subjected to a dry heat treatment to produce a nonwoven fabric a having a basis weight of 50 g / m ² and a thickness of 0.42 mm.

(Nonwoven fabric b)
As the thermoplastic resin, a polypropylene resin composition having a melting point of 163 ° C. and a charge stabilizer added thereto was used. The melt blown nonwoven fabric was manufactured using the apparatus which consists of an extruder and a gear pump, a melt blow nozzle, a compressed air generator and an air heater, a collection conveyor, and a winder.

After adjusting the spray flow rate so as to collect the meltblown fiber stream with respect to the collecting drum while tilting it toward the sheet traveling direction, it is electret processed by the pure water suction method, the basis weight is 30 g / m ² , and the average A nonwoven 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 in a mass ratio of 70/30 (zeolite / low density polyethylene), After stirring with a shaker, the mixture was uniformly sprayed onto the nonwoven 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., and the nonwoven fabric b was covered from the hot press. Thus, a deodorant fiber sheet A was prepared, and the composition and the like of the gas adsorbent are shown in Table 1. The physical properties and performance of the deodorant fiber sheet are shown in Table 3.

[Example 2]
(Deodorant fiber sheet)
73.7 / 26.3 (gas adsorbent B / low density polyethylene) of 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. Weighed at a mass ratio, stirred with a shaker, and then uniformly spread on the nonwoven fabric a so as to have a total amount of 95 g / m ^{2. In} a state where the hot melt adhesive was dissolved in a drying oven at 150 ° C. Then, the nonwoven fabric b was covered and heat-pressed to produce a deodorant fiber sheet B. The composition and the like of the gas adsorbent are shown in Table 1. The physical properties and performance of the deodorant fiber sheet are shown in Table 3.

[Example 3]
(Deodorant fiber sheet)
55.6 / 15.9 / 28 gas adsorbent including 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. .6 (gas adsorbent A / activated carbon A / low density polyethylene) was weighed, stirred with a shaker, and then uniformly spread on the nonwoven fabric a to a total amount of 63 g / m ^2. In a state where the hot melt adhesive was dissolved in a drying oven at 0 ° C., the non-woven fabric b was covered and hot pressed to produce a deodorant fiber sheet C. The composition of the gas adsorbent and the like are shown in Table 1. Table 3 shows the physical properties and performance of the fiber sheet.

[Example 4]
(Deodorant fiber sheet)
55.6 / 15.9 / 28.6 (gas adsorbent) of 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. (A / activated carbon B / low density polyethylene) and weighed with a shaker and sprayed uniformly on the nonwoven fabric a to a total amount of 63 g / m ^2. Hot in a drying oven at 150 ° C. In a state where the melt adhesive was dissolved, the nonwoven fabric b was covered and hot pressed to produce a deodorant fiber sheet D. The composition of the gas adsorbent, etc. are shown in Table 1. Physical properties and performance of the deodorant fiber sheet Is shown in Table 3.

[Example 5]
(Deodorant fiber sheet)
By impregnating the nonwoven fabric a in an aqueous solution in which the gas adsorbent E, adipic acid dihydrazide and 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 nonwoven fabric sheet c having a basis weight 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 be 7 g / m ^{2. The} hot melt adhesive was melted in a 130 ° C. drying oven. In this state, the nonwoven fabric b was covered and hot pressed to produce a deodorant fiber sheet E. The composition and the like of the gas adsorbent are shown in Table 1. The physical properties and performance of the deodorant fiber sheet are shown in Table 3. .

[Comparative Example 1]
(Deodorant fiber sheet)
The mass ratio of 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 is 70.0 / 30.0 (activated carbon B / low density polyethylene). After weighing and stirring with a shaker, it was uniformly sprayed on the nonwoven fabric a so as to have a total amount of 50 g / m ^{2. In} a state where the hot-melt adhesive was dissolved in a drying oven at 150 ° C., the nonwoven fabric b was coated thereon. The deodorant fiber sheet F was produced by covering with heat and the composition of the gas adsorbent is shown in Table 2. The physical properties and performance of the deodorant fiber sheet are shown in Table 3.

[Comparative Example 2]
(Deodorant fiber sheet)
The mass ratio of 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 is 70.0 / 30.0 (activated carbon C / low density polyethylene). After weighing and stirring with a shaker, it was uniformly sprayed on the non-woven fabric a so as to have a total amount of 265 g / m ^{2. A} non-woven fabric b was formed on the hot melt adhesive in a drying oven at 150 ° C. The deodorant fiber sheet G was manufactured by covering with heat and the composition of the gas adsorbent is shown in Table 2. The physical properties and performance of the deodorant fiber sheet are shown in Table 3.

[Comparative Example 3]
(Deodorant fiber sheet)
Mass 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 The mixture was weighed in a ratio and stirred with a shaker, and then uniformly spread on the nonwoven fabric a so as to have a total amount of 50 g / m ^{2. From} the state in which the hot melt adhesive was dissolved in a drying oven at 150 ° C. The nonwoven fabric b was covered and heat-pressed to produce a deodorant fiber sheet H. The composition and the like of the gas adsorbent are shown in Table 2. The physical properties and performance of the deodorant fiber sheet are shown in Table 3.

[Comparative Example 4]
(Deodorant fiber sheet)
Mass of 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 with the porous silica B The mixture was weighed in a ratio and stirred with a shaker, and then uniformly spread on the nonwoven fabric a so as to have a total amount of 50 g / m ^{2. From} the state in which the hot melt adhesive was dissolved in a drying oven at 150 ° C. The nonwoven fabric b was covered and heat pressed to produce a deodorant fiber sheet I. The composition of the gas adsorbent, etc. are shown in Table 2. The physical properties and performance of the deodorant fiber sheet are shown in Table 3.

[Comparative Example 5]
(Deodorant fiber sheet)
A 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)) 55.6 / 15.9 / 28.6 as a hot melt adhesive. Weighed at a mass ratio of (porous silica A / activated carbon C / low density polyethylene), stirred with a shaker, and then uniformly spread on the nonwoven fabric a so that the total amount was 63 g / m ² . In a state where the hot-melt adhesive was dissolved in a drying oven, the nonwoven fabric b was covered and hot pressed to produce a deodorant fiber sheet J. The composition of the gas adsorbent, etc. are shown in Table 2. The deodorant fiber sheet. Table 3 shows the physical properties and performance.

[Comparative Example 6]
(Deodorant fiber sheet)
70.0 / 30.0 (gas adsorbent D / low density polyethylene) of 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. Weighed at a mass ratio, stirred with a shaker, and then uniformly spread on the nonwoven fabric a so as to have a total amount of 50 g / m ^{2. In} a state where the hot melt adhesive was dissolved in a drying oven at 150 ° C. Then, the nonwoven fabric b was covered and heat-pressed to produce a deodorant fiber sheet K. The composition of the gas adsorbent and the like are shown in Table 2. The physical properties and performance of the deodorant fiber sheet are shown in Table 3.

[Comparative Example 7]
(Deodorant fiber sheet)
Impregnating the nonwoven fabric a in an aqueous solution in which the gas adsorbent F, adipic acid dihydrazide and 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 nonwoven fabric sheet d having a basis weight 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 nonwoven fabric d so as to be 7 g / m ^{2. The} hot melt adhesive was melted in a 130 ° C. drying oven. In this state, the nonwoven fabric b was covered and heat pressed to produce a deodorant fiber sheet L. The composition of the gas adsorbent, etc. are shown in Table 2. The physical properties and performance of the deodorant fiber sheet are shown in Table 3. .

[Comparative Example 8]
(Deodorant fiber sheet)
By impregnating the nonwoven fabric a into an aqueous solution in which the gas adsorbent G, adipic acid dihydrazide and 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 nonwoven fabric sheet e having a basis weight 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 nonwoven fabric e so as to be 7 g / m ^{2. The} hot melt adhesive was melted in a 130 ° C. drying oven. In this state, the nonwoven fabric b was covered and hot pressed to produce a deodorant fiber sheet M. The composition of the gas adsorbent and the like are shown in Table 2. The physical properties and performance of the deodorant fiber sheet are shown in Table 3. .

(15) Summary of Examples The gas adsorbents of Examples 1 and 2 had a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 2 to 20 to which adipic acid dihydrazide was adhered, and had 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 aldehydes, were excellent. In the evaluation of desorption odor after adsorption saturation, both acetaldehyde gas and toluene gas were 1.0 or less, and almost no odor was generated.

Furthermore, Example 3 and Example 4 contain a smaller amount of activated carbon. Due to the effect of zeolite with adipic acid dihydrazide attached, it was excellent in acetaldehyde removal performance, and due to the combined effect with activated carbon, more excellent results were obtained in the evaluation of desorption odor after adsorption saturation of toluene and acetaldehyde. In Example 4, since the adipic acid dihydrazide was adhered to the activated carbon, the effect of improving the acetaldehyde desorption odor appeared remarkably.

In Example 5, a fine powdery zeolite having a particle size of 5.0 μm is fixed to a nonwoven fabric with a binder, but as in Examples 1 and 2, it has excellent acetaldehyde removal performance and evaluates desorption odor after adsorption saturation. In Fig. 1, both acetaldehyde gas and toluene gas were 1.0 or less, and good results with almost no odor were obtained.

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

In Comparative Example 3, adipic acid dihydrazide is adhered to porous silica, so that acetaldehyde removal performance is excellent even with a small amount of gas adsorbent. However, toluene is physically adsorbed in mesopores peculiar to silica. The maximum desorption concentration increased to 5.8 ppm, and it was 3.0 even in the 6-step odor determination method. As a result, an odor component that was not a problem at the original 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 greatly reduced. As shown in Comparative Example 5, the desorption performance tends to be improved by mixing with activated carbon, but the result of the acetaldehyde 6-step odor determination method exceeds 2.0. The level needed improvement.

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

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

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

The gas adsorbent, deodorant fiber sheet and air filter according to the present invention are excellent in adsorption performance of low-boiling aldehydes in VOC components, and from low-boiling aldehydes and low-polarity gas adsorbents generated from the passenger compartment. In particular, it is preferably used as an air filter for purifying the air in the passenger compartment of automobiles and railway vehicles.

Claims

Containing a proton type Y zeolite and a water-soluble acid hydrazide compound,
The proton type Y-type zeolite contains SiO 2 and Al 2 O 3 ,
A gas adsorbent in which the molar ratio of SiO 2 to Al 2 O 3 in the proton-type Y-type zeolite (containing mole of SiO 2 / containing mole of Al 2 O 3 ) is 2 or more and 20 or less.
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 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 comprising 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 deodorizing fiber sheet according to claim 5 or 6.
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;
Treating the zeolite with an ammonium nitrate solution at 100-120 ° C .;
Calcining the zeolite with superheated steam at 500 to 800 ° C .;
A method for producing a gas adsorbent, comprising the step of adhering a water-soluble acid hydrazide compound to the zeolite in this order.