JP6942460B2 - Adsorbent for odorous substances - Google Patents

Description

The present invention relates to an adsorbent for odorous substances.

In recent years, there is an increasing need for deodorization by consumers. Among them, aldehyde compounds such as formaldehyde and acetaldehyde are considered to be causative substances of sick house syndrome and are difficult to be adsorbed by an adsorbent, so that there is a high demand for deodorization. As an adsorbent for such an odorous substance, for example, a hydrazine compound is known.

Among them, adipic acid dihydrazide has good aldehyde adsorption performance. In addition, adipic acid dihydrazide has high storage stability in the neutral region and has heat resistance of 200 ° C or higher (decomposition temperature in TG-DTA is about 230 to 275 ° C).

As described above, although high adsorption performance can be obtained by using the hydrazine compound, there is still a growing need for further improvement in adsorption performance and adsorption rate. For example, by mixing a hydrazine compound and silica, heat resistance is imparted and adsorption performance is enhanced.

However, hydrazine compounds have reduced storage stability under acidic or basic conditions. Since silica has properties as a solid acid, it is very difficult to commercialize an adsorbent containing the hydrazine compound and silica because the storage stability is usually lowered when the hydrazine compound and silica are mixed. rice field. In particular, storage stability may not be a problem at room temperature, but storage stability is particularly low at high temperatures in midsummer, aldehyde compounds cannot be sufficiently adsorbed, and the problem of unpleasant odor may not be solved. .. It is also known that coloring occurs as the storage stability of the hydrazine compound decreases. For example, Patent Document 1 describes that the dihydrazide compound is decomposed by the catalytic action of the pore surface of an _{inorganic powder (SiO 2 or the like), but the details have not yet been clarified.} .. In Patent Document 1, this problem is solved by heating the deodorant composition at a specific temperature so that the amount of water increases, but the decomposition of the hydrazine compound is not suppressed, and the decomposition is not suppressed. Since it is kept to a minimum, the effect of improving storage stability is insufficient.

International Publication No. 2013/118714

As described above, the current situation is that the decomposition of the hydrazine compound cannot be suppressed when the hydrazine compound and silica are mixed. Coloring occurs as the storage stability of the hydrazine compound decreases. It is essential to improve the storage stability of the hydrazine compound also in order to avoid coloring.

Therefore, an object of the present invention is to provide an adsorbent for an odorous substance (aldehyde compound or the like) that can improve storage stability and avoid coloring even when a hydrazine compound and silica are mixed. do.

As a result of intensive research to achieve the above object, the present inventors have ^{adopted silica having a surface silanol group density of 5.0 elements / nm 2} or less when the hydrazine compound and silica are mixed. However, it was found that the storage stability can be improved and coloring can be avoided. Based on such findings, the present inventors have further studied and completed the present invention. That is, the present invention includes the following configurations.
Item 1. Contains acid hydrazide compound and silica, and
The silica is an adsorbent for odorous substances having a surface silanol group density of 5.0 elements / nm ^{2 or less.}
Item 2. Item 2. The adsorbent for an odorous substance having a water content of 5.0% by mass or less.
Item 3. Item 2. The adsorbent according to Item 1 or 2, wherein the silica is at least one selected from the group consisting of wet silica, dry silica and molten silica.
Item 4. Item 1-3, wherein the acid hydrazide compound is at least one selected from the group consisting of carbodihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebatic acid dihydrazide, dodecandioic acid dihydrazide, and isophthalate dihydrazide. The adsorbent according to any one of.
Item 5. Item 2. The adsorbent according to any one of Items 1 to 4, wherein the silica has a specific surface area of 100 to 1000 m ^{2 / g.}
Item 6. Item 2. The adsorbent according to any one of Items 1 to 5, wherein the odorous substance is an aldehyde compound.
Item 7. Item 2. The method for producing an adsorbent according to any one of Items 1 to 6.
(II) A production method comprising a step of mixing the acid hydrazide compound and the silica.
Item 8. Before step (II)
(I) The production method according to Item 7, further comprising a step of heating silica at 300 ° C. or higher.
Item 9. Item 8. The production method according to Item 7 or 8, which does not include a step of heating after the step (II).
Item 10. An industrial product containing the adsorbent according to any one of Items 1 to 6.
Item 11. It is a method of adsorbing an odorous substance to an adsorbent by bringing a gas containing an aldehyde compound into contact with the adsorbent.
A method in which the adsorbent contains an acid hydrazide compound and silica, and the silica has a surface silanol group density of 5.0 elements / nm ² or less.

Since the adsorbent of the present invention contains an acid hydrazide compound and ^{silica having a surface silanol group density of 5.0 elements / nm 2} or less, storage stability can be improved and coloring can be avoided. Can be done.

1. 1. Adsorbent The adsorbent of the present invention contains an acid hydrazide compound and silica, and the silica is an adsorbent for an odorous substance having a ^{surface silanol group density of 5.0 elements / nm 2 or less.}

Since the adsorbent of the present invention uses silica having a surface silanol group density of 5.0 elements / nm ² or less, it has excellent storage stability despite containing an acid hydrazide compound and silica. Silica can also be avoided.

(1-1) Acid Hydrazide Compound The acid hydrazide compound is not particularly limited, and a conventionally known compound can be used. For example, use an acid monohydrazide compound having one hydrazide group in the molecule, an acid dihydrazide compound having two hydrazide groups in the molecule, an acid trihydrazide compound having three hydrazide groups in the molecule, and the like. Can be done. Of these, acid dihydrazide compounds or acid trihydrazide compounds are preferable from the viewpoints of adsorption performance of odorous substances (aldehyde compounds and the like), storage stability of adsorbents, color suppression and the like. Among them, the acid dihydrazide compound is preferably a general-purpose compound. This acid hydrazide compound is a compound having an action of adsorbing an odorous substance (aldehyde compound or the like).

From the viewpoint of adsorption performance and adsorption rate, the molecular weight of the acid hydrazide compound is, for example, preferably 30 or more, more preferably 60 or more, and even more preferably 90 or more. The molecular weight of the acid hydrazide compound is, for example, preferably 300 or less, more preferably 280 or less, and even more preferably 260 or less, from the viewpoint of adsorption performance and adsorption rate. Further, the molecular weight of the acid hydrazide compound is preferably 100 or more, more preferably 130 or more, for example, from the viewpoint of heat resistance and storage stability as additional performance. The molecular weight of the acid hydrazide compound is preferably 300 or less, more preferably 270 or less, for example, from the viewpoint of heat resistance and storage stability as additional performance.

Specific examples of such acid hydrazide compounds include carbodihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipate dihydrazide, sebatic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, trihydrazide citrate, and pyromellitic acid. Examples thereof include trihydrazide, 1,2,4-benzenetricarboxylic acid trihydrazide, nitrilotriacetic acid trihydrazide, and 1,3,5-cyclohexanetricarboxylic acid trihydrazide. Of these, adipic acid dihydrazide and succinic acid dihydrazide are preferable from the viewpoint of excellent balance between safety, adsorption performance, adsorption rate, color suppression, heat resistance and storage stability. These acid hydrazide compounds can be used alone or in combination of two or more.

The content of the acid hydrazide compound is preferably, for example, 2 parts by mass or more with respect to 100 parts by mass of silica, which will be described later, from the viewpoint of further improving adsorption performance, adsorption rate, color suppression, heat resistance and storage stability. More than parts by mass is more preferable, and more than 5 parts by mass is further preferable. The content of the acid hydrazide compound is preferably 80 parts by mass or less, preferably 40 parts by mass or less, with respect to 100 parts by mass of silica described later, from the viewpoint of further improving adsorption performance, adsorption rate, heat resistance and storage stability. More preferably, it is 20 parts by mass or less, and further preferably 20 parts by mass or less.

The content of the acid hydrazide compound in the adsorbent of the present invention is not particularly limited, and the total amount of the adsorbent is 100% by mass from the viewpoint of further improving adsorption performance, adsorption rate, color suppression, heat resistance and storage stability. For example, 0.1% by mass or more is preferable, 1.0% by mass or more is more preferable, and 3.0% by mass or more is further preferable. The content of the acid hydrazide compound in the adsorbent of the present invention is not particularly limited, and the total amount of the adsorbent is set to 100% by mass from the viewpoint of further improving the adsorption performance, adsorption rate, heat resistance and storage stability. For example, 90.0% by mass or less is preferable, 50.0% by mass or less is more preferable, and 20.0% by mass or less is further preferable.

(1-2) Silica The silica contained in the adsorbent of the present invention has a surface silanol group density of 5.0 elements / nm ² or less.

The silanol group density is calculated from the specific surface area of silica particles measured by the BET method using nitrogen gas and the number of silanol groups measured in accordance with JIS K 1150-1994, per ^{1 nm 2 surface area of silica particles.} When this silanol group density is high, the acid hydrazide compound becomes unstable when mixed with the acid hydrazide compound, so that the storage stability of the obtained adsorbent becomes poor and it becomes easy to color. .. From this point of view, the silanol group density on the silica surface is 5.0 elements / nm ² or less, preferably 4.8 ^{elements / nm 2} or less, and more preferably 4.5 elements / nm ² or less. On the other hand, the lower limit of the silanol group density on the silica surface is not particularly limited, and is usually 0.1 pieces / nm ² or more, preferably 1.4 pieces / nm ² or more, and more preferably 2.6 pieces / nm ² or more.

The silica used in the present invention has a 1050 ° C. ignition loss of 4.0% by mass measured in accordance with JIS K 1150-1994 from the viewpoint of further improving adsorption performance, adsorption rate, color suppression, heat resistance and storage stability. It is preferably less than or equal to, more preferably 3.7% by mass or less, and further preferably 3.0% by mass or less. The lower limit of the 1050 ° C. ignition loss measured in accordance with JIS K 1150-1994 of the silica used in the present invention is not particularly limited, and is usually preferably 0.2% by mass or more, preferably 0.5% by mass. The above is more preferable, and 0.8% by mass or more is further preferable. The 1050 ° C ignition loss of silica is measured in accordance with JIS K 1150-1994.

^{The silica used in the present invention preferably has a specific surface area of 1000 m 2} / g or less, preferably 600 m ² / g or less, from the viewpoint of further improving adsorption performance, color suppression, adsorption rate, heat resistance and storage stability. More preferably, it is more preferably 570 m ² / g or less. ^{The lower limit of the specific surface area of silica used in the present invention is preferably 100 m 2} / g or more, preferably 200 m, from the viewpoint of further improving adsorption performance, color suppression, adsorption rate, heat resistance and storage stability. more preferably ² / g or more, further preferably 300 meters ² / g or more. The specific surface area of silica is measured by the BET method using nitrogen gas.

The silica used in the present invention preferably has an average particle size of 3.0 μm or more, more preferably 5.0 μm or more, from the viewpoint of further improving adsorption performance, color suppression, adsorption rate, heat resistance, and storage stability. Further, the silica used in the present invention preferably has an average particle size of 20.0 μm or less, more preferably 15.0 μm or less, from the viewpoint of further improving adsorption performance, color suppression, adsorption rate, heat resistance and storage stability. In the present invention, D50 measured by the laser method is defined as the average particle size of silica.

Examples of such silica include wet silica (precipitated silica, gel silica, etc.), dry silica, fused silica, and the like. In particular, it is preferable to use wet silica (precipitated silica, gel silica, etc.) because the silanol group density can be easily controlled. In particular, by heating these silicas under the conditions described below, the silanol group density can be further reduced, the hydrazine compound can be further stabilized, and coloring can be further suppressed.

The content of silica in the adsorbent of the present invention is not particularly limited, and the total amount of the adsorbent is set to 100% by mass from the viewpoint of further improving adsorption performance, adsorption rate, color suppression, heat resistance and storage stability. For example, 10.0% by mass or more is preferable, 50.0% by mass or more is more preferable, and 80.0% by mass or more is further preferable. The content of silica in the adsorbent of the present invention is not particularly limited, and the total amount of the adsorbent is 100% by mass from the viewpoint of further improving adsorption performance, adsorption rate, color suppression, heat resistance and storage stability. For example, 99.9% by mass or less is preferable, 99.0% by mass or less is more preferable, and 97.0% by mass or less is further preferable.

(1-3) Adsorbent supported on carrier
In the present invention, since the silica functions as a carrier for the acid hydrazide compound, a silica on which the acid hydrazide compound is supported (impregnated) can be used as an adsorbent (hereinafter, referred to as "supported adsorbent"). Sometimes). A carrier other than silica can also be used.

When a porous carrier other than silica is used, the porous carrier is not particularly limited, and generally known carriers can be widely used. For example, zeolite, alumina, ceramic, diatomaceous earth, activated charcoal, clay, talc, etc. Calcium carbonate and the like can be mentioned. These porous carriers can be used alone or in combination of two or more.

The adsorbent of the present invention preferably has a water content of 5.0% by mass or less, more preferably 4.4% by mass or less, from the viewpoint of further improving storage stability, adsorption performance, adsorption rate, and further suppressing coloring. It is preferably 3.0% by mass or less, and more preferably 3.0% by mass or less. The lower limit of the water content of the adsorbent of the present invention is not particularly limited, and is usually preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and preferably 0.3% by mass or more. More preferred. The water content of the adsorbent of the present invention is measured by the volatile content after heating at 105 ° C. for 2 hours.

In order to produce the adsorbent of the present invention having such conditions, it is preferable to use silica having ^{a surface silanol group density of 5.0 elements / nm 2 or less as described above.} The hygroscopicity of such silica is controlled, whereby the water content of the adsorbent of the present invention can be adjusted (reduced).

(1-4) Suspension Adsorbent, Powder Adsorbent or Pellet Adsorbent In the present invention, after producing the above-mentioned supported adsorbent, it is dispersed in a solvent to form a suspension agent, which is used as an adsorbent. You can also. It can also be mixed with powder and used as a powder. It can also be used as pellets.

Examples of the solvent include water, lower alcohols, polyhydric alcohols, ketones, ethers, esters, aromatic solvents, halogenated hydrocarbon solvents, polar organic solvents and the like.

Examples of the lower alcohol include alcohols having a linear or branched alkyl group having 1 to 4 carbon atoms. Specific examples thereof include methanol, ethanol, n-propanol, isopropanol, n-butanol and the like.

Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and ethylene glycol monomethyl. Examples thereof include ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether.

Examples of the ketone include acetone, methyl ethyl ketone, methyl isobutyl ketone, propylene carbonate and the like.

Examples of the ether include dioxane, tetrahydrofuran, diethyl ether and the like.

Examples of the ester include ethyl acetate, butyl acetate, isobutyl acetate, 3-methyl-3-methoxybutyl acetate, γ-butyrolactone, dimethyl adipate, dimethyl glutarate, dimethyl succinate and the like.

Examples of the aromatic solvent include benzene, toluene, xylene, methylnaphthalene, dimethylnaphthalene, isopropylnaphthalene, diisopropylnaphthalene, ethylbiphenyl, diethylbiphenyl, solvent naphtha and the like.

Examples of the halogenated hydrocarbon solvent include carbon tetrachloride, chloroform, methylene chloride and the like.

Examples of the polar organic solvent include dimethylformamide, dimethylacetamide, dimethyl sulfoxide, acetonitrile, N-methylpyrrolidone and the like.

Among these, at least one selected from the group consisting of water, lower alcohols and polyhydric alcohols is preferable, and water is more preferable, from the viewpoint of further improving the adsorption performance and the adsorption rate. These solvents can be used alone or in combination of two or more.

The various adsorbents of the present invention are widely and generally formulated with known additives such as non-volatile acids and chelating agents, as well as antioxidants and light stabilizers, depending on the purpose and use thereof. Various additives used in the above can be blended.

Preferred non-volatile acids include succinic acid, fumaric acid, maleic acid, boric acid and the like, and salts thereof can also be used. These non-volatile acids can be used alone or in combination of two or more. By blending such a non-volatile acid, the storage stability of the adsorbent can be further improved.

When a non-volatile acid is used, its content is not particularly limited, and is preferably about 1 to 10% by weight, with the total amount of the adsorbent being 100% by weight.

Examples of the chelating agent include ethylenediaminetetraacetic acid, glycol etherdiaminetetraacetic acid, oxalic acid, citric acid and the like, and salts thereof can also be used. These chelating agents may be used alone or in combination of two or more. By blending such a chelating agent, the storage stability of the adsorbent can be further improved.

When a chelating agent is used, its content is not particularly limited, and is preferably about 1 to 10% by weight, with the total amount of the adsorbent being 100% by weight.

Examples of the antioxidant include a phenol-based antioxidant, an amine-based antioxidant and the like. Specific examples of the phenolic antioxidant include 2,6-di-tert-butyl-4-methylphenol and 2,2'-methylenebis (4-methyl-6-tert-butylphenol). Specific examples of the amine-based antioxidant include alkyldiphenylamine, N, N'-di-sec-butyl-p-phenylenediamine and the like. These antioxidants may be used alone or in combination of two or more.

When an antioxidant is used, its content is not particularly limited, and is preferably about 1 to 10% by weight, with the total amount of the adsorbent being 100% by weight.

Examples of the light stabilizer include hindered amine-based light stabilizers such as bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate. These light stabilizers can be used alone or in combination of two or more.

When a light stabilizer is used, its content is not particularly limited, but is preferably about 1 to 10% by weight, with the total amount of the adsorbent being 100% by weight.

These additives can be used alone or in combination according to the purpose.

The above-mentioned various adsorbents of the present invention may be prepared under cooling, at room temperature, or under heating, but are preferably performed at 5 to 40 ° C.

(1-5) Method for Producing Adsorbent The adsorbent of the present invention as described above is, for example,
(II) It can be produced by a method comprising a step of mixing the acid hydrazide compound and the silica.

As the mixing method, a usual method can be adopted, for example, a ball mill, a rod mill, a bead mill, a nauta mixer, a ribbon mixer, a V-type mixer, a locking mixer, a high speed mixer, a Henschel mixer, a super mixer, a jet mill, an atomizer, and the like. It can be mixed by a hammer mill, a screw feeder, an agitator, a dancing agitator, a double cone mixer, or the like.

This mixing can be either a wet blend (wet mixing) or a dry blend (dry mixing). In the wet blending method, even when silica having a silanol group density of 5.0 or less is used, the silanol group density may become 5.0 or more by contacting with water once, so that it is particularly preferable to dry. A blend (dry mixing) can be adopted. In this case, the decrease in storage stability due to the influence of moisture can be further suppressed, the storage stability can be further improved not only at room temperature but also at high temperature, and coloring can be further suppressed while maintaining adsorption performance. can do.

In addition, the production method of the present invention is described before the above step (II).
(I) It is preferable to include a step of heating silica at 300 ° C. or higher. This makes it possible to more reliably obtain silica having a surface silanol group density of 5.0 elements / nm ^{2 or less.}

By heating at 300 ° C or higher, the silanol group density on the surface can be further reduced, the 1050 ° C ignition loss measured in accordance with JIS K 1150-1994 can be further reduced, and the silanol group weight can be further reduced. .. Moreover, the water content of the obtained adsorbent can be further reduced. The heating temperature adjusts the silanol group density on the surface of silica, ignition loss at 1050 ° C, silanol group weight, specific surface area, etc. more appropriately, further improves the storage stability of the adsorbent of the present invention, and further improves the storage stability of the adsorbent of the present invention, and odorous substances (aldehydes). From the viewpoint of further improving the adsorption performance of (compounds, etc.), 350 ° C. or higher is preferable, and 400 ° C. or higher is more preferable. The upper limit of the heating temperature is not particularly limited, but is usually preferably 1000 ° C. or lower, more preferably 900 ° C. or lower, and even more preferably 800 ° C. or lower. The heating time is preferably a time during which the silanol group density on the surface can be sufficiently reduced, and is preferably 5 minutes or more, for example. The heating method is not particularly limited, and can be performed by a conventionally known method such as a standing method or a flow method. In particular, from the viewpoint of productivity, continuous kiln heating by the flow method is preferable.

Examples of the silica used in the step of heating at 300 ° C. or higher include wet silica (precipitation silica, gel silica, etc.), dry silica, molten silica, etc., and the silanol group density in the above range and / or Wet method silica is preferable from the viewpoint that silica having a specific surface area can be easily adjusted.

As a method for obtaining silica having a surface silanol group density of 5.0 elements / nm ² or less, in addition to the method of heating at 300 ° C. or higher, a method of reacting a silanol group on the silica surface with a compound of a silane coupling agent (chemical modification). Law) is also mentioned. Examples of silica that can be used in this chemical modification method include wet silica (precipitated silica, gel silica, etc.), dry silica, molten silica, and the like.

As a method for obtaining silica having a surface silanol group density of 5.0 elements / nm ² or less, a method of heating at 300 ° C. or higher from the viewpoint of changes in silica surface physical properties due to a chemical modification method and the problem of residual chemical substances used for modification. Is preferable.

(1-6) Odorous Substances The above-mentioned adsorbent of the present invention can efficiently and quickly adsorb odorous substances (particularly aldehyde compounds). In particular, since the adsorbent of the present invention is excellent in storage stability, the adsorption performance of odorous substances (particularly aldehyde compounds) can be maintained for a long period of time not only at room temperature but also at high temperature. The adsorbent of the present invention is effective against the above-mentioned odorous substance of one kind or a combination of two or more kinds.

The adsorbed substance to be adsorbed by the adsorbent of the present invention is not particularly limited, and examples thereof include aldehyde-based odorous substances (aldehyde compounds). Specific examples thereof include formaldehyde, acetaldehyde, propionaldehyde, achlorine, and the like. Aldehyde-based odorous substances (aldehyde compounds) such as n-butylaldehyde, isobutylaldehyde, 3-methyl-butylaldehyde, and crotonaldehyde; alcohols such as pentanal, hexanal, heptanal, octanal, nonanal, and decanal; and alic acid and the like. Among them, the adsorbent of the present invention is particularly effective for adsorbing formaldehyde and / or acetaldehyde.

2. Industrial Products Containing Adsorbents The adsorbents of the present invention can be used by being included (blended) in industrial products. The industrial product includes the present invention (industrial product of the present invention).

The industrial products refer to industrial products and industrial raw materials that are widely known in the past. Specifically, paints, adhesives, inks, sealants, paper products, binders, resin emulsions, pulp, wood materials, wood products, plastic products, films, wallpaper, building materials (interior materials, ceiling materials, floor materials, etc.) , Textile products, filters, etc.

In the industrial product of the present invention, the content of the adsorbent of the present invention is not particularly limited and can be appropriately set depending on the industrial product and its intended use.

3. 3. Method for Adsorbing Odorous Substances Using Adsorbent In the method for adsorbing odorous substances of the present invention, a gas containing an aldehyde compound is brought into contact with the adsorbent of the present invention to adsorb the odorous substance to the adsorbent of the present invention. .. According to the above-mentioned adsorption method, since the adsorbent of the present invention efficiently and quickly adsorbs an odorous substance (particularly an aldehyde compound), the above-mentioned odorous substance (particularly an aldehyde compound) can be removed efficiently and quickly. Further, since the adsorbent of the present invention is excellent in storage stability not only at room temperature but also at high temperature, the adsorption performance of odorous substances (aldehyde compounds and the like) can be further maintained. In the adsorption method of the present invention, the above-mentioned industrial product of the present invention containing the adsorbent of the present invention is brought into contact with a gas containing an odorous substance (particularly an aldehyde compound), whereby the adsorbent and the above-mentioned odorous substance (particularly an aldehyde compound) are brought into contact with each other. ), And as a result, the above-mentioned odorous substance can be efficiently adsorbed and removed.

Further, by filling an adsorption device such as a fixed bed, a moving bed, or a fluidized bed and ventilating a gas containing an odorous substance (particularly an aldehyde compound), the odorous substance can be efficiently, quickly, and lengthened. It can be adsorbed and removed over time.

Hereinafter, the present invention will be specifically described with reference to Examples. However, it goes without saying that the present invention is not limited to the aspects of the following examples.

Each parameter of silica used in Examples and Comparative Examples was measured by the following method.

Silanol radix
The number of silanol groups in 1 g of silica was calculated according to JIS K 1150-1994.

Specific Surface Area The specific surface area of silica was measured by the BET method using nitrogen gas using TriStar3000 manufactured by Micromeritics.

Silanol group density The silanol group density (silanol group number / specific surface area) was calculated from the number of silanol groups and the specific surface area.

1050 ℃ Ignition loss
The loss on ignition of silica at 1050 ° C was measured in accordance with JIS K 1150-1994.

Silanol group weight
The silanol group weight (mass%) was calculated from the loss on ignition at 1050 ° C by the following formula.

(34/18) × (Ignition loss at 1050 ° C)
Bulk density
Bulk density was measured in accordance with JIS K 6220-1: 2015 7.8.2.

Average particle size _{D 50} was measured by the laser method using a Malvern master sizer S and used as the average particle size.

Comparative example 1
10 parts by mass of adipic acid dihydrazide and 100 parts by mass of silica (gel method silica manufactured by Mizusawa Industrial Chemicals Co., Ltd .; Mizukasil P-758C) were dry-mixed with a dancing agitator to prepare an adsorbent of Comparative Example 1. The silica used had a silanol group weight of 8.9 mass%, a specific surface area of 572 m ² / g, a silanol group density of 5.5 pieces / nm ² , a strong heat loss of 4.7 mass% at 1050 ° C, a bulk density of 0.31 g / cm ³ , and an average grain size. The diameter was 5.7 μm.

Comparative example 2
Instead of adipic acid dihydrazide, 50 parts by mass of a 20% aqueous solution of adipic acid dihydrazide (the content of adipic acid dihydrazide is 10 parts by mass) was used, and the comparison was performed in the same manner as in Comparative Example 1 except that the mixture was wet-mixed with a dancing agitator. The adsorbent of Example 2 was obtained.

Example 1
Silica (gel method silica manufactured by Mizusawa Industrial Chemicals Co., Ltd .; Mizukasil P-758C) was heated at 400 ° C. for 1 hour under an atmospheric atmosphere. As the silica, the adsorbent of Example 1 was obtained in the same manner as in Comparative Example 1 except that the silica heated at 400 ° C. was used as the silica. The silica used had a silanol group weight of 7.0% by mass, a specific surface area of 570 m ² / g, a silanol group density of 4.3 pieces / nm ² , a strong heat loss of 3.7 mass% at 1050 ° C, a bulk density of 0.32 g / cm ³ , and an average grain size. The diameter was 5.9 μm.

Example 2
Silica (gel method silica manufactured by Mizusawa Industrial Chemicals Co., Ltd .; Mizukasil P-758C) was heated at 600 ° C. for 1 hour under an atmospheric atmosphere. As the silica, the adsorbent of Example 2 was obtained in the same manner as in Comparative Example 1 except that the silica heated at 600 ° C. was used as the silica. The silica used was silanol group weight 4.0% by mass, specific surface area 555 m ² / g, silanol group density 2.5 pieces / nm ² , 1050 ° C strong heat loss 2.1% by mass, bulk density 0.33 g / cm ³ , average grain. The diameter was 5.7 μm.

Example 3
Silica (gel method silica manufactured by Mizusawa Industrial Chemicals Co., Ltd .; Mizukasil P-758C) was heated at 800 ° C. for 1 hour under an atmospheric atmosphere. As the silica, the adsorbent of Example 3 was obtained in the same manner as in Comparative Example 1 except that the silica heated at 800 ° C. was used as the silica. The silica used had a silanol group weight of 1.9% by mass, a specific surface area of 504 m ² / g, a silanol group density of 1.3 pieces / nm ² , a strong heat loss of 1.0 mass% at 1050 ° C, a bulk density of 0.35 g / cm ³ , and an average grain size. The diameter was 5.5 μm.

Comparative example 3
As the silica, the adsorbent of Comparative Example 3 was obtained in the same manner as in Comparative Example 1 except that the gel method silica manufactured by Mizusawa Industrial Chemicals Co., Ltd .; Mizuka Sorb C-1 was used instead of Mizukasil P-758C. The silica used had a silanol group weight of 6.2% by mass, a specific surface area of 370 m ² / g, a silanol group density of 6.0 pieces / nm ² , a strong heat loss of 3.3% by mass at 1050 ° C, a bulk density of 0.22 g / cm ³ , and an average grain size. The diameter was 10.6 μm.

Example 4
Silica (gel method silica manufactured by Mizusawa Industrial Chemicals Co., Ltd .; Mizuka Sorb C-1) was heated at 400 ° C. for 1 hour under an atmospheric atmosphere. As the silica, the adsorbent of Example 4 was obtained in the same manner as in Comparative Example 1 except that the silica heated at 400 ° C. was used in this manner. The silica used was silanol group weight 4.3% by mass, specific surface area 370 m ² / g, silanol group density 4.2 pieces / nm ² , 1050 ° C strong heat loss 2.3% by mass, bulk density 0.23 g / cm ³ , average grain. The diameter was 10.6 μm.

Example 5
Silica (gel method silica manufactured by Mizusawa Industrial Chemicals Co., Ltd .; Mizuka Sorb C-1) was heated at 600 ° C. for 1 hour in an air atmosphere. As the silica, the adsorbent of Example 5 was obtained in the same manner as in Comparative Example 1 except that the silica heated at 600 ° C. was used as the silica. The silica used was silanol group weight 2.5% by mass, specific surface area 377 m ² / g, silanol group density 2.3 pieces / nm ² , 1050 ° C strong heat loss 1.3% by mass, bulk density 0.24 g / cm ³ , average grain. The diameter was 10.6 μm.

Example 6
Silica (gel method silica manufactured by Mizusawa Industrial Chemicals Co., Ltd .; Mizuka Sorb C-1) was heated (calcined) at 800 ° C. for 1 hour in an air atmosphere. As the silica, the adsorbent of Example 6 was obtained in the same manner as in Comparative Example 1 except that the silica heated at 800 ° C. was used in this manner. The silica used was silanol group weight 1.5% by mass, specific surface area 350 m ² / g, silanol group density 1.5 pieces / nm ² , 1050 ° C strong heat loss 0.8% by mass, bulk density 0.24 g / cm ³ , average grain. The diameter was 10.2 μm.

Example 7
As the silica, the adsorbent of Example 7 was obtained in the same manner as in Comparative Example 1 except that the gel method silica manufactured by Mizusawa Industrial Chemicals Co., Ltd .; Mizuka Sorb C-6 was used instead of Mizukasil P-758C. The silica used was silanol group weight 3.2% by mass, specific surface area 366 m ² / g, silanol group density 3.1 pieces / nm ² , 1050 ° C strong heat loss 1.7% by mass, bulk density 0.23 g / cm ³ , average grain. The diameter was 10.5 μm.

Test example (moisture)
The volatile residue when the adsorbent was heated at 105 ° C. for 2 hours was measured and used as water.

Test Example (Storage Stability (Adipic Acid Dihydrazide Residual Rate))
The adsorbents obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were kept at 60 ° C. for 2 weeks. Then, the amount of adipic acid dihydrazide remaining in the adsorbent was determined by the HPLC method.

Table 1 shows the silica and its physical properties used in each Example and Comparative Example, the mixing ratio of silica and adipic acid dihydrazide, the water content of each adsorbent, and the residual ratio of adipic acid dihydrazide. In Table 1, ADH represents adipic acid dihydrazide.

Test example (coloring)
Approximately 5 g of the test piece was packed in Unipack D-8 manufactured by Japan, and the color tone (L *, a *, b *) of the test piece was measured with the color measurement system CM-3500d manufactured by Konica Minolta. The color difference E * was calculated from the color tone before and after the application at 60 ° C for 2 weeks. The results are shown in Table 2.

Test example (acetaldehyde adsorption performance)
77 mg of the adsorbents of Examples 1 to 3 and Comparative Example 1 were sampled in an aluminum petri dish, sealed in a 1 L tedler bag, and then 1 L of 1000 ppm aldehyde gas was added. Starting from the time of gas injection, the gas concentration was measured over time after 0.5 hours, 1.0 hours, 2.0 hours, 6.0 hours and 24.0 hours. The results are shown in Table 3.

Tables 2 and 3 show the coloring test of each adsorbent and the test results of acetaldehyde adsorption performance. In Tables 2 and 3, ADH represents adipic acid dihydrazide.

As described above, in Comparative Examples 1 to 3 using silica having a surface silanol group density of more than 5.0 elements / nm ^{2, the} residual rate of adipic acid dihydrazide was inferior when kept at 60 ° C. for 2 weeks. For this reason, the adsorbents of Comparative Examples 1 to 3 maintain the adsorption performance of odorous substances (aldehyde compounds, etc.) for a long period of time because adipic acid dihydrazide, which has the adsorption performance of odorous substances (aldehyde compounds, etc.), does not easily remain. It is suggested that this is difficult. Moreover, the adsorbent of Comparative Example 1 could not suppress coloring. On the other hand, in Examples 1 to 7 using silica having a surface silanol group density of 5.0 elements / nm ² or less, adipic acid dihydrazide was retained at 89% or more even after being maintained at 60 ° C. for 2 weeks. Therefore, although the adsorbents of Examples 1 to 7 use silica, which is reported to easily decompose adipic acid dihydrazide, the adsorbent has the ability to adsorb odorous substances (aldehyde compounds, etc.). Since dihydrazide tends to remain, it is suggested that the adsorption performance of odorous substances (aldehyde compounds, etc.) can be maintained for a long period of time. Moreover, the adsorbents of Examples 1 to 3 were able to suppress coloring. Therefore, in the adsorbent of the present invention, it is possible to prevent the decomposition of adipic acid dihydrazide, maintain the adsorption performance of odorous substances (aldehyde compounds, etc.) for a long period of time, suppress coloring, and use silica. It is also possible to further impart the intended properties such as heat resistance.

Claims (11)

Contains acid hydrazide compound and silica, and
The silica is an adsorbent for odorous substances having a surface silanol group density of 5.0 elements / nm ^{2 or less.} The adsorbent for an odorous substance according to claim 1, wherein the water content is 5.0% by mass or less. The adsorbent according to claim 1 or 2, wherein the silica is at least one selected from the group consisting of wet silica, dry silica and molten silica. The acid hydrazide compound is at least one selected from the group consisting of carbodihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebatic acid dihydrazide, dodecanedioic acid dihydrazide, and isophthalic acid dihydrazide, claims 1 to 1. The adsorbent according to any one of 3. The adsorbent according to any one of claims 1 to 4, wherein the specific surface area of the silica is 100 to 1000 m ^{2 / g.} The adsorbent according to any one of claims 1 to 5, wherein the odorous substance is an aldehyde compound. The method for producing an adsorbent according to any one of claims 1 to 6.
(II) A production method comprising a step of mixing the acid hydrazide compound and the silica. Before step (II)
(I) The production method according to claim 7, further comprising a step of heating silica at 300 ° C. or higher. The production method according to claim 7 or 8, which does not include a step of heating after the step (II). An industrial product comprising the adsorbent according to any one of claims 1 to 6. It is a method of adsorbing an odorous substance to an adsorbent by bringing a gas containing an aldehyde compound into contact with the adsorbent.
A method in which the adsorbent contains an acid hydrazide compound and silica, and the silica has a surface silanol group density of 5.0 elements / nm ² or less.