TWI697357B - Chemical filter - Google Patents

Abstract

The invention provides a chemical filter material for removing siloxane compounds, which can efficiently remove siloxane compounds in a low-concentration environment and can be easily prepared.

The chemical filter material for removing siloxane compounds of the present invention is characterized in that an inorganic silica-based porous material is used as an adsorbent, and a mixed solution when the inorganic silica-based porous material is mixed with pure water (content ratio: 5wt%) pH is 7 or less.

Description

Chemical filter

The present invention relates to a chemical filter material for removing silicone compounds from fluids (especially in air). In addition, the present invention relates to a fluid purification method using the chemical filter material, and a gas sensor equipped with the chemical filter material.

In the living environment, siloxane compounds exist in all environments. For example, silicone compounds are used in filling parts or sealing materials in buildings such as general homes and clean rooms, and adhesives, shampoos, cosmetics, etc. used in construction sites. All substances.

In the exposure step of the semiconductor process, disilazane compounds such as hexamethyldisilazane (HMDS) are known to be used as photoresist adhesion agents. HMDS, for example, is sprayed on the surface of the wafer by being made into a gas to replace the hydroxyl groups on the surface of the wafer with trimethylsilanol groups to make the surface of the wafer hydrophobic and make the surface of the wafer and the photoresist Improved adhesion. However, in the presence of siloxane compounds in the air, if the siloxane compounds adhere to the surface of the wafer, it will cause the characteristics of the semiconductor to change. Even low concentrations may reduce the product yield.

In order to remove siloxane compounds, activated carbon is usually used As a chemical filter material for adsorbent. As an adsorbent using activated carbon, for example, activated carbon for siloxane removal having two types of activated carbons with different average pore diameters is known (refer to Patent Document 1).

In addition to activated carbon, resins or porous materials into which acidic functional groups such as sulfonic acid groups are introduced are also used as adsorbents for silicone compounds. As such adsorbents, for example, a silicone remover containing a resin having a sulfonic acid group (see Patent Document 2), and a porous material in which a sulfonic acid group modified metal oxide sol is added to a porous material are known. (Refer to Patent Documents 3 and 4), a silicone remover containing an acidic compound with a dissociation constant of 2.2 or less and a molecular weight of 1000 or less in an inorganic porous body with an average pore diameter of 3-20 nm (see Patent Document 5) Wait. It is described that if such a resin or porous material into which an acidic functional group is introduced is used as an adsorbent, silicones can be selectively removed efficiently.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2005-177737

[Patent Document 2] JP 2011-212565 A

[Patent Document 3] JP 2013-103153 A

[Patent Document 4] JP 2013-103154 A

[Patent Document 5] Japanese Patent Application Publication No. 2015-44175

However, as in the aforementioned patent document 1, activated carbon is used as In the case of adsorbents, the siloxanes that were once adsorbed will be separated.

In addition, siloxane compounds often exist in the atmosphere together with other gas components such as organic gas components in a normal environment. Therefore, in the presence of a large number of other gas components, as described in Patent Document 1, the use of activated carbon adsorbents, because the removal of siloxane compounds and the removal of other gas components will become a competitive relationship, the removal of siloxane compounds The efficiency (removal performance, or removal capacity) will vary with the presence of other gas components. Moreover, the amount of other gas components present in the atmosphere varies from day to day. Therefore, because the amount of siloxane compounds and other gas components removed by activated carbon changes every day, it is difficult to predict the residual life of the adsorbent using activated carbon or the filter material using the adsorbent.

Patent Document 2 uses a strong acid type ion exchange resin. However, resins with sulfonic acid groups generally have a low adsorption capacity for silicone compounds. Regardless of whether they are supported by a porous support or not, there is a problem that they cannot sufficiently remove silicone gases. Furthermore, because of the high molecular weight of the resin, there is often resin near the sulfonic acid group, but the aforementioned resin has a low silicone compound adsorption capacity, and the reaction between the sulfonic acid group and the silicone compound slows down. The issue of separation.

In addition, in Patent Document 2, cyclic silicones are polymerized and adsorbed by a strong acid type ion exchange resin. The adsorbed silicone gases in Patent Document 5 are activated by acidic compounds, and the non-activated silicon Oxyane gas reacts and adsorbs. In this way, it is described in Cited Documents 2 and 5 that siloxane compounds are reacted with each other and adsorbed. However, when the concentration of the siloxane compound in the air is extremely low, the removal efficiency of this method cannot be said to be sufficient because the siloxane compounds do not easily react with each other.

In Patent Documents 3 and 4, a material in which a sulfonic acid group modified metal oxide sol is added to a porous material is used. However, in order to obtain such a sulfonic acid group modified metal oxide sol, it must be produced in a cumbersome process, and it is impossible to easily obtain an adsorbent or a chemical filter material that can efficiently remove siloxane compounds.

Therefore, there is a need for a chemical filter material that can efficiently remove siloxane compounds in a low-concentration environment and can be easily prepared.

Therefore, the object of the present invention is to provide a chemical filter material for the removal of siloxane compounds, which can efficiently remove siloxane compounds in a low-concentration environment and can be easily prepared. In addition, another object of the present invention is to further provide a chemical filter material for removing siloxane compounds that can selectively remove siloxane compounds.

The inventors of the present invention, as a result of intensive research in order to achieve the above purpose, found that if an inorganic silica-based porous material with a pH of 7 or less in a water mixture with pure water is used as an adsorbent, it can be removed extremely efficiently. Silicone compounds in fluids (especially in air), and completed the present invention.

That is, the present invention provides a chemical filter material for removing siloxane compounds, which uses an inorganic silica-based porous material with a pH of 7 or less in a water mixture (content ratio: 5 wt%) obtained by mixing with pure water. Adsorbent.

In the chemical filter material for removing siloxane compounds, the inorganic silica-based porous material may be selected from the group consisting of zeolite, silica gel, alumina silica, aluminum silicate, porous glass, diatomaceous earth, and hydration Magnesium silicate clay minerals, allophane (allophane), silk At least one of the group of bauxite, acid clay, activated clay, activated bentonite, mesoporous silica, aluminosilicate, and fumed silica Or two or more inorganic silica-based porous materials.

In the chemical filter material for removing siloxane compounds, as the adsorbent, an inorganic silica-based porous material with a pH of 7 or less of the water mixture (content ratio: 5 wt%) and other adsorbents may be used together.

The chemical filter material for removing silicone compounds may also contain at least 10% by weight relative to the total weight of the adsorbent, selected from the group consisting of synthetic zeolite, diatomaceous earth, silica gel, and activated clay As the aforementioned inorganic silica-based porous material.

The chemical filter material for removing siloxane compounds includes synthetic zeolite as the inorganic silica-based porous material, and the ratio of SiO ₂ to Al ₂ O ₃ (mole ratio) in the synthetic zeolite [SiO ₂ /Al ₂ O ₃ ] can be 4~2000.

The chemical filter material for removing siloxane compounds includes synthetic zeolite as the inorganic silica-based porous material, and the synthetic zeolite may be selected from ferrierite, MCM-22, ZSM-5, ZSM- 11. A synthetic zeolite with a framework structure of at least one of the group of mordenite, Beta type, X type, Y type, and potassium zeolite.

The aforementioned inorganic silica-based porous material may be an inorganic silica-based porous material whose ignition loss (ignition loss) obtained by the following formula (1) is 7.0% or less.

Loss on ignition I(%)=(W ₁ -W ₂ )/W ₁ ×100. . . (1)

W ₁ ：The mass of the sample after drying

W ₂ ：The mass of sample after burning

[In formula (1), the mass of the sample after drying (W ₁ ) is the inorganic silica-based porous material heated at about 170°C in air or 150°C in vacuum for 2 hours The quality of the material. The mass of the sample after ignition (W ₂ ) is the mass of the inorganic silica-based porous material obtained by burning the inorganic silica-based porous material of the dried sample at 1000℃±50℃ for 2 hours ].

The chemical filter material may be a chemical filter material in which the adsorbent is attached to the filter material base material by a binder.

In the aforementioned chemical filter material for removing silicone compounds, the aforementioned binder may be a binder having a pH of 7 or less in a water mixture (content ratio: 5 wt%) obtained by mixing with pure water.

In the aforementioned chemical filter material for removing silicone compounds, the aforementioned binder may be an inorganic binder.

In the aforementioned chemical filter material for removing silicone compounds, the aforementioned binder may be colloidal inorganic oxide particles.

The structure of the aforementioned chemical filter material may have at least one structure selected from the group consisting of a honeycomb structure, a pleats structure, a three-dimensional mesh structure, a sheet packaging structure, and a sheet structure.

The aforementioned honeycomb structure may be a honeycomb structure, or a cross-section of a lattice, circular, wavy, polygonal, indefinite shape, or a shape with all or part of a curved surface, which is a structure through which fluid (especially air) can pass. The structure of the element's cell.

The chemical filter material for removing siloxane compounds mentioned above can include The pelletized chemical filter material of the aforementioned adsorbent.

In the aforementioned pelletizing, a binder having a pH of 7 or less of a water mixture (content ratio: 5 wt%) obtained by mixing with pure water can be used.

The structure of the filter material containing the aforementioned pelletized adsorbent may have at least one structure selected from the group consisting of a pleated structure, a pellet filling structure, a three-dimensional mesh structure, a sheet packaging structure, and a sheet structure.

The aforementioned chemical filter material for removing silicone compounds may be a chemical filter material manufactured by a papermaking method.

The aforementioned chemical filter material for siloxane compound removal may be a ceramic type chemical filter material.

The aforementioned chemical filter material for removing siloxane compounds may be a chemical filter material in which the adsorbent is attached to the filter material base material without using a binder.

The present invention further provides a gas sensor including the aforementioned chemical filter material for removing siloxane compounds.

The present invention further provides a resin composition, which is the resin composition used in the chemical filter medium for removing silicone compounds, and includes the inorganic silica-based porous material and resin.

According to the chemical filter material of the present invention, since the siloxane compound once adsorbed will not be separated again, the removal effect is longer than that of activated carbon. In addition, since it is not necessary to react the siloxane compounds with each other when removing the siloxane compounds, it can be removed efficiently even in a low-concentration environment. In addition, the preparation of adsorbents and chemical filter materials does not require complicated steps, so they can be easily obtained. Furthermore, the chemical filter material according to the present invention can selectively remove siloxane compounds. Therefore, namely The siloxane compound can be efficiently removed in an environment where the siloxane compound and other gas components exist together. In addition, it becomes easier to predict the remaining life of the chemical filter medium.

Furthermore, according to the chemical filter material of the present invention, especially because it can remove siloxane compounds in the air extremely efficiently, the amount of adsorbent used can be reduced to a very small amount, and the amount of the filter material substrate can be reduced. It can save energy, low cost and space.

1‧‧‧Pipe string

2‧‧‧Pipe

3‧‧‧Flowmeter

4‧‧‧Flow adjustment valve

5‧‧‧Pump

6‧‧‧Non-woven fabric

7‧‧‧Test sample (adsorbent)

Figure 1 is a schematic diagram of the ventilation test device used in the examples.

Figure 2 is a partial schematic cross-sectional view of the ventilation test device used in the examples.

Figure 3 is a graph showing the results of the ventilation test of Example 1 (the relationship between the pH of the water mixture of zeolite and the removal efficiency).

Figure 4 is a graph showing the results of the ventilation test of Example 1 (the relationship between the pH of the water mixture of silica gel, acid clay, activated clay, and diatomaceous earth and the removal efficiency).

Figure 5 is a graph showing the results of the ventilation test of Example 4 (the relationship between the pH of the water mixture of zeolite and diatomaceous earth and the removal efficiency).

[The form of implementing the invention]

[Chemical Filter Material]

The chemical filter material for removing silicone compounds of the present invention is an inorganic silica-based porous material with a pH of 7 or less in a water mixture (content ratio: 5 wt%) obtained by mixing with pure water. Silicon is used as an adsorbent Oxane Chemical filter media for compound removal. In addition, in this specification, the "chemical filter medium for removing siloxane compounds of the present invention" may be simply referred to as the "chemical filter medium of the present invention". In addition, in this specification, an adsorbent using an inorganic silica-based porous material having a pH of 7 or less with a water mixture obtained by mixing with pure water (content ratio: 5 wt%) is called "the adsorbent of the present invention "The situation. In addition, in this specification, the "pH of the water mixture" refers to the "pH of the water mixture (content ratio: 5 wt%)" unless otherwise specified.

(Adsorbent of the present invention)

The chemical filter material of the present invention uses an inorganic silica-based porous material as an essential adsorbent. The above-mentioned inorganic silica-based porous material may be used only one type or two or more types.

In the chemical filter material of the present invention, the above-mentioned inorganic silica-based porous material has a pH of 7 or less (for example, 3 to 7) of a water mixture (content ratio: 5 wt%) obtained by mixing it with pure water, preferably less than 7 (for example, 3 or more and less than 7), more preferably 3 to 6.5, still more preferably 4 to 6. With the above pH being 7 or less, siloxane compounds can be removed with high efficiency.

In this specification, the so-called pH of the water mixture (content ratio: 5 wt%) obtained by mixing with pure water refers to the content ratio of the substance (target substance) mixed in the water mixture relative to the entire water mixture The pH measured under the condition of 5wt%. For example, the pH of an inorganic silica-based porous material mixed with pure water (content ratio: 5wt%) is measured under the condition that the inorganic silica-based porous material content is 5wt% The pH at the time. The pH of the water mixture can be measured with a pH measuring device, for example. Also, using the above inorganic When an additive or the like is added to the silica-based porous material as the adsorbent of the present invention, the above-mentioned "pH of the water mixture (content ratio: 5wt%) obtained by mixing with pure water" means the addition of The pH of the water mixture (content ratio: 5wt%) obtained by mixing the inorganic silica-based porous material with pure water in the state before the agent, etc. (that is, the state without adding the additive, etc.).

In this specification, the water mixture (content ratio: 5wt%) can be produced, for example, according to the following "method of making water mixture (content ratio: 5wt%)".

Water mixture (content ratio: 5wt%) production method

The above-mentioned water mixture (content ratio: 5wt%), for example, a sample (also referred to as the "target sample") that is the pH measurement target of the water mixture can be mixed with pure water so that the content ratio becomes 5wt%, and then thoroughly stirred Made by standing still. In the preparation of the above water mixture, pure water is used, but a mixed solvent of an organic solvent and pure water may also be used. However, when an organic solvent is used, the acid dissociation constant varies greatly with the type and concentration of the organic solvent. Therefore, it is generally a water-soluble organic solvent such as alcohol, and is set to a range that does not significantly affect the pH. concentration. Among them, the above-mentioned "wt%" has the same meaning as "wt%". In order to prepare a water mixture with a content of 5 wt%, specifically, 5 g of a target sample can be weighed, for example, using a weighing scale, and pure water is further added to make the whole mixture 100 g, and the solution can be fully stirred. For example, an inorganic silica-based porous material water mixture (content ratio: 5 wt%) can be produced using the inorganic silica-based porous material as the target sample.

The above-mentioned inorganic silica-based porous material used in the chemical filter medium of the present invention is not particularly limited, but the specific surface area (BET specific surface area) may be 10 m ² /g or more (for example, 10 to 800 m ² /g). It is preferably 50 m ² /g or more (for example, 50 to 750 m ² /g), and more preferably 100 m ² /g or more (for example, 100 to 700 m ² /g).

The above-mentioned inorganic silica-based porous material is not particularly limited, but the content of SiO ₂ in the porous material can be 5% by weight or more (for example, 5-100% by weight), preferably 50% by weight Above, more preferably 65% by weight or more, and still more preferably 75% by weight or more of inorganic silica-based porous materials.

The inorganic silica-based porous material is not particularly limited, but examples include zeolite (for example, synthetic zeolite, natural zeolite, etc.), silica gel, alumina silica, aluminum silicate, porous glass, diatomaceous earth, Hydrated magnesium silicate clay minerals (for example, talc), allophane, filamentous bauxite, acid clay, activated clay, activated bentonite, mesoporous silica, aluminosilicate, fumed silica, etc. . By using the above-mentioned inorganic silica-based porous material as an adsorbent, siloxane compounds can be removed with high efficiency. Among them, zeolite, diatomaceous earth, silica gel, and activated clay are preferred, and synthetic zeolite, diatomaceous earth, silica gel, and activated clay are more preferred. If zeolite (especially synthetic zeolite), diatomaceous earth, silica gel, or activated clay is used as the adsorbent, the siloxane compounds can be removed continuously and efficiently over a longer period of time. Among them, in the case of using zeolite (especially synthetic zeolite) and silica gel as the inorganic silica-based porous material, there are two types of siloxane compounds, linear siloxane compounds and cyclic siloxane compounds, with remarkable removal efficiency. The tendency to ascend. In addition, when silica gel and diatomaceous earth are used as inorganic silica-based porous materials, they can be removed more selectively The tendency of the silicone compound. The above-mentioned inorganic silica-based porous material may be used only one type or two or more types. Wherein, the above-mentioned synthetic zeolite refers to including artificial zeolite. In addition, only one type of the above-mentioned zeolite may be used, or two or more types may be used.

The above-mentioned zeolite is a porous material having a skeleton mainly composed of silicon element (Si), aluminum element (Al), and oxygen element (O). However, part or all of the aluminum element (Al) in the skeleton may be Replaced with trivalent metal elements such as iron element (Fe), boron element (B), and gallium element (Ga); divalent metal elements such as zinc element (Zn).

The pore structure of the above-mentioned zeolite is not particularly limited. The number of ring members of the zeolite is not particularly limited, but is, for example, 4-20, preferably 8-20, and more preferably 10-12. Here, the number of ring members of the zeolite is represented by the number of O atoms in the structure of the largest pore ring among the pore rings contained in the zeolite. Furthermore, the pore channel system of the zeolite is not particularly limited, but it is preferably 1 to 3 dimensions, more preferably 2 to 3 dimensions, and still more preferably 3 dimensions. Particularly preferred is a zeolite (especially a synthetic zeolite) having a pore structure with a ring number of 12 and a three-dimensional pore channel system. If the number of ring members and/or the pore channel system of the zeolite is within the above range, the removal efficiency of the siloxane compound tends to be higher.

The synthetic zeolite mentioned above is not particularly limited, but examples thereof include type A, ferrierite, MCM-22, ZSM-5, ZSM-11, SAPO-11, mordenite, Beta type, X type, Y type, Synthetic zeolite with framework structure such as L-type, chabazite, potassium zeolite, etc. The above-mentioned framework structure is preferably ferrierite, MCM-22, ZSM-5, ZSM-11, mordenite, Beta type, X type, Y type, and potassium zeolite. In addition, the above-mentioned synthetic zeolite may use one type of zeolite with a framework structure, or a combination of two or more types Zeolite is used.

As the artificial zeolite, for example, generally, zeolite produced from waste containing silicon or aluminum such as coal ash discharged from coal-fired power plants or paper sludge incineration ash discharged from paper mills. The artificial zeolite mentioned above may be used alone or in combination of two or more kinds.

The above-mentioned natural zeolite is not particularly limited, but for example, clinoptilolite, mordenite, chabazite, sodium zeolite, cellulose zeolite, barium zeolite, analcime, leucite, aluminum calcium zeolite, Water calcium zeolite, Pauling zeolite, phillipsite zeolite, zeolite, erionite, faujasite, ferrierite, mutinaite, tshernichite, heulandite, stilbite, blade zeolite, aluminosilicate, Phosphate sodium beryllium silicate (beryllosilicate) (roggianite (roggianite), fluorosilicate beryllium lithium monetite, etc.), zinc silicate (zinc-sodalite), etc. The above-mentioned natural zeolite may be used alone or in combination of two or more kinds.

The pH of the water mixture (content ratio: 5 wt%) obtained by mixing the above zeolite with pure water is 7 or less (for example, 3 to 7), preferably less than 7 (for example, 3 or more and less than 7), more preferably 3~6.8, more preferably 3.5~6.7, particularly preferably 4~6.5. Among them, the water mixture of zeolite (content ratio: 5wt%) can be produced by using the above-mentioned "Method for preparing water mixture (content ratio: 5wt%)", using zeolite as the target sample.

The ratio of SiO ₂ to Al ₂ O ₃ (molar ratio) [SiO ₂ /Al ₂ O ₃ ] in the above synthetic zeolite is not particularly limited, but from the viewpoint of the removal efficiency of siloxane compounds, it can be 4~ 2000, preferably 5 to 1500, more preferably 10 to 1000, still more preferably 12 to 600. The above-mentioned [SiO ₂ /Al ₂ O ₃ ] is considered to be an index showing the hydrophilicity or hydrophobicity of zeolite. If [SiO ₂ /Al ₂ O ₃ ] is high (that is, the ratio of silica is high and the ratio of alumina is low), the hydrophobicity tends to become high. On the other hand, if [SiO ₂ /Al ₂ O ₃ ] is low (that is, the ratio of silica is low and the ratio of alumina is high), the hydrophilicity tends to become high. If the hydrophilicity is too high (that is, the hydrophobicity is too low), the surface of the framework will be covered with water molecules, and it will become difficult for the hydrophobic silicone compound to approach the adsorption site (adsorption site). If the hydrophilicity is too low (that is, the hydrophobicity is too high), the acid points in the zeolite decrease, and the removal efficiency of the siloxane compound tends to be low. Therefore, for example, by setting [SiO ₂ /Al ₂ O ₃ ] within the above range, the hydrophilicity or hydrophobicity of the zeolite can be appropriately adjusted, and the removal efficiency of the siloxane compound can be more excellent. Among them, when the siloxane compound is a cyclic siloxane compound, the above-mentioned synthetic zeolite is preferably highly hydrophobic, and preferably [SiO ₂ /Al ₂ O ₃ ] is high.

The above-mentioned zeolite is not particularly limited, but may contain cations in the framework structure. The cation is not particularly limited, but for example, hydrogen ion (H ⁺ ); ammonium ion (NH ₄ ⁺ ); alkyl-substituted ammonium ion (for example, methylammonium ion ((CH ₃ )H ₃ N ⁺ ) , Dimethylammonium ion ((CH ₃ ) ₂ H ₂ N ⁺ ), trimethylammonium ion ((CH ₃ ) ₃ HN ⁺ ), tetramethylammonium ion ((CH ₃ ) ₄ N ⁺ ), etc.); aryl or aromatic Alkyl-substituted ammonium ions; lithium ions (Li ⁺ ), sodium ions (Na ⁺ ), potassium ions (K ⁺ ) and other alkali metal ions; magnesium ions (Mg ²⁺ ), calcium ions (Ca ²⁺ ), barium Alkaline earth metal ions such as ions (Ba ²⁺ ); zinc ions (Zn ²⁺ ), tin ions (Sn ²⁺ , Sn ⁴⁺ ), iron ions (Fe ²⁺ , Fe ³⁺ ), platinum ions (Pt ^{2 +} ), palladium ion (Pd ²⁺ ), titanium ion (Ti ³⁺ ), silver ion (Ag ⁺ ), copper ion (Cu ⁺ , Cu ²⁺ ), manganese ion (Mn ²⁺ , Mn ⁴⁺ ), cobalt Transition metal ions such as ions (Co ²⁺ ); gallium ions (Ga ⁺ ), etc. The said cation may contain only 1 type, and may contain 2 or more types. The content of the cation in the zeolite is not particularly limited.

However, the specific surface area (BET specific surface area), average particle diameter, average pore diameter (diameter), total pore volume, and the like of the zeolite are not particularly limited. In addition, only one type of the above-mentioned zeolite may be used, or two or more types may be used.

As the above-mentioned zeolite, an acid-treated product obtained by acid treatment of natural zeolite or synthetic zeolite, a hydrothermal treatment product obtained by hydrothermal treatment of natural zeolite or synthetic zeolite, and ammonium obtained by firing treatment of ammonium zeolite can be used. Processed product, proton type zeolite. Among them, the acid used in the above-mentioned acid treatment can be the acid used in the well-known or commonly used acid treatment, and examples thereof include hydrochloric acid, nitric acid, and citric acid. In addition, the type of acid used in the acid treatment, the acid concentration of the acid aqueous solution used in the acid treatment, the acid treatment time, and the like are not particularly limited.

The above-mentioned acid-treated product and the above-mentioned hydrothermal treatment product are presumably because the acid in the acid treatment or the heating steam in the hydrothermal treatment removes the cations from the aluminum element in the zeolite and increases the silanol groups in the zeolite, but When the pH of the mixture becomes 7 or less, the removal efficiency of the siloxane compound becomes higher.

Examples of the proton-type zeolite include those in which at least a part of all cations (for example, metal ions, ammonium ions, etc.) other than hydrogen ions in natural zeolite or synthetic zeolite are replaced with hydrogen ions to contain a large amount of hydrogen ions. Synthetic zeolite produced by the same method. In addition, the proton-type zeolite can also be produced by ion-exchanging cations such as sodium ions in natural zeolite or synthetic zeolite into ammonium ions, and then calcining them. Also, generally speaking, zeolite obtained by substituting hydrogen ions for cations in zeolite is called proton For the proton-type zeolite, it is sufficient to substitute at least a part of the cations in the zeolite with hydrogen ions, and it is not limited to substitute all the cations in the zeolite with hydrogen ions.

Although proton-type zeolite is used as a catalyst, it is generally not used as an adsorbent. In addition, even if it is considered that zeolite may be used as an adsorbent, the zeolite used as an adsorbent is alkaline, that is, almost always the pH of the water mixture is greater than 7. As a specific aspect of zeolite used as an adsorbent, for example, the well-known molecular sieve, but the substance removed by the molecular sieve is water, which is the molecular sieve function of zeolite, and is mainly coordinated to the Na ions in the zeolite by water. Metal ions are removed. In the case of using Na ions in zeolite like this, the pH of the water mixture of the zeolite used is greater than 7. Furthermore, there are very few examples of solid acid zeolite being used as an adsorbent. For example, there are those that utilize the acid and ion exchange capacity of solid acid zeolite to remove basic compounds such as ammonia through a neutralization reaction. However, the current situation is that the object of removal is limited to inorganic compounds or basic compounds. In other words, there has been no example of using zeolite with a water mixture pH of 7 or less for the removal of siloxane compounds of organic compounds.

The acid clay is not particularly limited, and it can be used for acid clay produced in various places. Examples include acid clay produced in Niigata Prefecture, Japan, and acid clay produced in Yamagata Prefecture, Japan. The above-mentioned acid clay may be used only one type or two or more types.

The above-mentioned activated clay is obtained by acid treatment of the above-mentioned acidic clay, for example, the above-mentioned acidic clay is subjected to acid treatment with an inorganic acid such as sulfuric acid so as not to completely destroy the basic structure of the montmorillonite. And dissolve out metal oxides such as Mg or Fe oxides , Increase the specific surface area and pore volume, etc. Only one kind of the above-mentioned activated clay may be used, or two or more kinds may be used.

The pH of the water mixture (content ratio: 5 wt%) obtained by mixing the acid clay and the activated clay with pure water is 7 or less (for example, 3 to 7), preferably less than 7 (for example, 3 or more and less than 7) ), more preferably 3~6.5, still more preferably 3.2~5, particularly preferably 3.5~4.7. In addition, the water mixture (content ratio: 5wt%) of acid clay and the water mixture (content ratio: 5wt%) of activated clay can be converted into acid clay by the above-mentioned "method of making water mixture (content ratio: 5wt%)" Or the activated clay is made as the object sample.

The above-mentioned diatomaceous earth is not particularly limited, and diatomaceous earth produced in various places can be used. It can be, for example, diatomaceous earth (diatomaceous shale) produced in Wakkanai, Hokkaido, Japan, diatomaceous earth produced in Akita Prefecture, Japan, diatomaceous earth produced in Garrison, Okayama Prefecture, Japan, diatomaceous earth produced in Kokonoe, Oita Prefecture, Japan, Ishikawa, Japan Any diatomaceous earth such as diatomaceous earth (diatom mudstone) produced in Noto Prefecture. Among them, diatomaceous earth produced in Wakkanai, Hokkaido, Japan is preferred. The above-mentioned diatomaceous earth may use only one type, or two or more types.

The pH of the water mixture (content ratio: 5 wt%) obtained by mixing the diatomaceous earth with pure water is 7 or less (for example, 3 to 7), preferably less than 7 (for example, 3 or more and less than 7), and more Preferably it is 3 to 6.7, further preferably 3.2 to 6.5, particularly preferably 3.5 to 6.2. In addition, the water mixture (content ratio: 5wt%) of diatomaceous earth can be produced by using the diatomaceous earth as a target sample by the above-mentioned "method for preparing water mixture (content ratio: 5wt%)".

As the above-mentioned silicone gel, an acid-treated product obtained by subjecting the silicone gel to acid treatment and then washing off the acid used in the treatment with water, etc. can be used . Among them, the acid used in the above-mentioned acid treatment may be the acid used in the well-known or commonly used acid treatment, and examples thereof include hydrochloric acid, nitric acid, and citric acid. In addition, the type of acid used in the acid treatment, the acid concentration of the acid aqueous solution used in the acid treatment, the acid treatment time, and the like are not particularly limited.

Inorganic silica-based porous materials other than synthetic zeolite, acid clay, activated clay, and diatomaceous earth (also called "other inorganic silica-based porous materials") are mixed with pure water to obtain a water mixture ( Content ratio: 5wt%) The pH is 7 or less (for example, 3~7), preferably less than 7 (for example, 3 or more and less than 7), more preferably 3 to 6.5, still more preferably 3.5 to 6.3, especially preferred For 4~6. In addition, the water mixture (content ratio: 5wt%) of other inorganic silica-based porous materials can be converted into other inorganic silica-based porous materials by the above-mentioned "method for preparing water mixture (content ratio: 5wt%)" The water mixture of the material was prepared as the target sample.

In inorganic silica-based porous materials other than synthetic zeolite, the content of SiO ₂ is not particularly limited, but may be 50% by weight or more relative to the total weight (100% by weight) of the inorganic silica-based porous materials (for example , 50-100% by weight), preferably 60% by weight or more, more preferably 70% by weight or more.

The aforementioned inorganic silica-based porous material is not particularly limited, but the loss on ignition is preferably 7.0% or less (for example, 2.5 to 7.0%), more preferably 3.0 to 6.0%, and still more preferably 3.5 to 4.5%. If activated clay with a water mixture pH of 7 or less and the aforementioned loss on ignition within the aforementioned range is used as the inorganic silica-based porous material, the removal performance of the silicone compound tends to be more excellent. Especially, about activated clay, diatomaceous earth, silicon The glue preferably has a loss on ignition within the above range. Furthermore, in the case of silicone, the loss on ignition is more preferably 3.0~7.0%, and still more preferably 3.5~6.0%.

The above-mentioned loss on ignition can be determined with reference to JIS K1150 (1994), for example. Specifically, the aforementioned loss on ignition is obtained by the following formula (1).

Loss on ignition I(%)=(W ₁ -W ₂ )/W ₁ ×100. . . (1)

W ₁ ：The mass of the sample after drying

W ₂ ：The mass of sample after burning

The mass (W ₁ ) of the sample after drying is the mass of the inorganic silica-based porous material after heating the inorganic silica-based porous material at about 170° C. in the air or at about 150° C. under vacuum for 2 hours. On the other hand, the mass of the sample after combustion (W ₂ ) is the inorganic silica-based porous material of the dried sample, which is obtained by burning at 1000℃±50℃ for 2 hours The quality of the material. The mass of the sample after drying (W ₁ ) and the mass of the sample after combustion (W ₂ ) can be measured with a scale or thermogravimetry (TG). For more detailed conditions for obtaining the above-mentioned loss on ignition, refer to JIS K1150 (1994).

The above-mentioned loss on ignition is considered to be an index showing the hydrophilicity or hydrophobicity of the inorganic silica-based porous material. If the ignition loss is high, the number of silanol groups in the inorganic silica-based porous material is large, and the hydrophilicity tends to increase. If the hydrophilicity is too high (that is, the hydrophobicity is too low), the surface of the inorganic silica-based porous material will be covered with water molecules, and the hydrophobic siloxane compound will become difficult to approach the adsorption site (adsorption site). However, the removal performance of silicone compounds tends to be low. On the other hand, if the ignition loss is low, the silanol in the inorganic silica-based porous material The number of groups is small, and the hydrophobicity tends to increase. If the hydrophobicity is too high (that is, the hydrophilicity is too low), the number of silanol groups is small, and the removal performance of the gas siloxane compound tends to decrease. Therefore, by setting the loss on ignition within the above range, the hydrophilicity or hydrophobicity of the inorganic silica-based porous material can be appropriately adjusted, and the removal efficiency of the silicone compound can be more excellent. In addition, the number of silanol groups described above can be expressed by the "number of silanol groups" defined in JIS K1150 (1994), and can be obtained from the loss on ignition.

The above-mentioned inorganic silica-based porous material is not particularly limited, but it is preferable that no additives or the like are added. That is, it is preferable that the inorganic silica-based porous material does not contain an inorganic silica-based porous material to which an additive or the like is added. Examples of the above-mentioned additives include acidic substances or alkaline substances. If an acidic substance is added, the skeleton of the inorganic silica-based porous material may change, or the pores may be filled with the acidic substance.

The adsorbent of the present invention is not particularly limited, but if necessary, it may contain adsorbents (other adsorbents) other than the inorganic silica-based porous material whose pH of the water mixture is 7 or less. That is, as the adsorbent of the present invention, an inorganic silica-based porous material having a pH of 7 or less of the above-mentioned water mixture can be used together with other adsorbents. Examples of the other adsorbents include porous materials other than inorganic silica-based porous materials whose pH of the water mixture is 7 or less, other silica, clay minerals, activated carbon, alumina, and glass. By using the above-mentioned other adsorbents together as adsorbents, it is possible to produce a chemical filter material that has the effects of other adsorbents in addition to the effects of the present invention.

The above-mentioned water mixture in the adsorbent of the present invention (in the full adsorbent) The content of the inorganic silica-based porous material with a compound pH of 7 or less is not particularly limited, but from the viewpoint of the removal efficiency of the siloxane compound, relative to the total weight (100% by weight) of the adsorbent, It is preferably 10% by weight or more (for example, 10 to 100% by weight), more preferably 30% by weight or more, still more preferably 50% by weight or more, and particularly preferably 70% by weight or more.

In the adsorbent of the present invention, the inorganic silica-based porous material having a pH of 7 or less as a water mixture preferably contains 10% by weight or more relative to the total weight (100% by weight) of the adsorbent (for example, 10-100% by weight, preferably 50% by weight or more, more preferably 70% by weight or more) of zeolite (especially synthetic zeolite), diatomaceous earth, silica gel, or activated clay. In addition, when the inorganic silica-based porous material includes two or more of zeolite (especially synthetic zeolite), diatomaceous earth, silica gel, and activated clay, the above content is the total of the two or more materials. content.

The chemical filter medium of the present invention is not particularly limited as long as it uses an inorganic silica-based porous material with a pH of 7 or less in a water mixture (content ratio: 5 wt%) as an adsorbent. As the above-mentioned chemical filter medium, for example, a chemical filter medium in which the adsorbent of the present invention is attached (fixed) to a filter medium base material. In addition, when the adsorbent of the present invention functions as a binder, the adsorbent can be attached to the filter material base without using a binder, but it is preferable to use a binder to allow the adsorbent of the present invention to adhere to the filter material base. material. That is, the above-mentioned chemical filter material may be a chemical filter material in which the adsorbent of the present invention is attached (or only the adsorbent of the present invention is attached) to the filter material substrate without using an adhesive, but it is preferable to use an adhesive to attach the present invention The adsorbent is attached to the chemical filter material of the filter material base material.

The adsorbent of the present invention is not particularly limited, but can be pelletized. That is, the adsorbent of the present invention may be a pelletized adsorbent. That is, the chemical filter material of the present invention may include the adsorbent of the present invention that has been pelletized. For the above-mentioned pelletization, for example, the powder of the adsorbent of the present invention can be granulated using the above-mentioned adhesive.

In addition, the adsorbent of the present invention can be mixed with resin and used as a resin composition. Examples of the resin composition include resin pellets and sheets (for example, a sheet produced using the above-mentioned resin pellets). Examples of the aforementioned sheet include films and fibrous substrates (woven fabrics, non-woven fabrics, etc.).

As the resin in the above-mentioned resin composition, well-known or commonly used thermoplastic resins can be used. Examples of the above resins include olefin resins such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polypropylene (PP), etc.; ionomers; ethylene-acrylic acid copolymers (EAA) , Ethylene-methacrylic acid copolymer (EMAA), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene-methacrylic acid Copolymers such as methyl ester copolymer (EMMA).

The above-mentioned resin is preferably a resin having a high melt flow rate (MFR) (for example, 10 g/10 min or more), a low melting point (low softening point), and excellent low-temperature draw down properties. If it is a resin with a high MFR, even when the MFR is reduced by adding the adsorbent of the present invention, it is easy to ensure a certain level of flow characteristics. In addition, if it has a low melting point, the extrudability at low temperature improves due to the resin softening at low temperature, and there is a tendency that it becomes difficult to foam. If it is a resin with excellent low-temperature stretchability, the extrusion moldability when the adsorbent of the present invention is added tends to improve.

The content of the adsorbent of the present invention in the above-mentioned resin composition is preferably as large as possible within the possible range of the target shape from the viewpoint of further improving the removal efficiency of the silicone compound. For example, in the case where the above-mentioned resin composition is a sheet, it is preferably as large as possible within the range where the sheet can be formed. The content of the adsorbent of the present invention in the above resin composition is not particularly limited, but relative to the total weight of the resin (100 parts by weight), it is preferably 1 to 200 parts by weight, more preferably 5 to 150 parts by weight, and More preferably, it is 10 to 120 parts by weight. When the inorganic silica-based porous material in the adsorbent of the present invention is zeolite, diatomaceous earth, or activated clay, the above content is preferably 50 to 200 parts by weight, more preferably 70 to 120 parts by weight.

(Filter material base material)

The filter medium base material is not particularly limited, and a filter medium base material generally used as a chemical filter medium can be used. Examples of the aforementioned filter material substrate include fibrous substrates (woven or non-woven fabrics) composed of fibers such as organic fibers or inorganic fibers, paper, foams composed of polyurethane foam, etc. Body, use refractory metal oxide or refractory inorganic substance (for example, aluminum and other metals, ceramics, etc.) filter material base material. The shape of the woven fabric of the fibrous base material is not particularly limited, and examples thereof include those in which fibers are knitted into a mesh shape. Among them, as the aforementioned filter material base material, a fibrous base material is preferred.

Examples of the fibers in the fibrous base material include alumina silica fibers, silica fibers, alumina fibers, mullite fibers, glass fibers, rock wool fibers, and carbon fibers. Inorganic fibers such as polyethylene fiber, polypropylene fiber, nylon fiber, polyester fiber (for example, polyethylene terephthalate fiber Etc.), organic fibers such as polytetrafluoroethylene fiber, polyvinyl alcohol fiber, amide fiber, pulp fiber, rayon fiber, etc. Among the above, from the viewpoint of increasing the strength of the chemical filter medium and from the viewpoint of less pollution caused by exhaust gas from the fiber, the inorganic fiber is preferable, and the glass fiber is more preferable. That is, as the aforementioned filter material base material, a fibrous base material (glass fabric (glass cloth)) using glass fibers is preferred. These fibers may be used alone or in combination of two or more kinds. In addition, the shapes of the inorganic fibers and the organic fibers are not particularly limited.

(Binder)

The above-mentioned binder can promote the adhesion of the adsorbent to the filter material base material, or be used for pelletizing the adsorbent. The above-mentioned binder is not particularly limited, and known or commonly used binders for filter media (for example, for air filter media, chemical filter media, etc.) can be used. As the above-mentioned binding agent, it may be an organic binding agent or an inorganic binding agent. The above-mentioned binder is not particularly limited, but it is preferably an inorganic binder. Only one kind of the above-mentioned binder may be used, or two or more kinds may be used.

The aforementioned binder may be acidic or alkaline, but is preferably acidic. If the aforementioned binder is acidic, the removal efficiency of the silicone compound tends to increase. The acidic binder, the pH of the water mixture (content ratio: 5 wt%) obtained by mixing in pure water is 7 or less (for example, 3 to 7), preferably less than 7 (for example, 3 or more and less than 7), More preferably, it is 3 to 6.8, still more preferably is 3.5 to 6.7, particularly preferably is 4 to 6.5. In addition, the water mixture (content ratio: 5wt%) of the binder can be produced by using the above-mentioned "Method for Producing Water Mixture (content ratio: 5wt%)" using the binder as the target sample. In addition, the above-mentioned bonding agent is a bonding agent containing a solvent such as colloidal silica In the case of the above-mentioned content ratio is relative to the content ratio of the solid content in the binder of the water mixture.

Examples of the above-mentioned organic binder include: polyethylene resins, polypropylene resins, acrylic resins such as methyl methacrylate, ABS resins, polyester resins such as PET, phenol resins, epoxy resins, and amines. Cellulose such as carbamate resin, vinyl acetate resin, polyvinyl alcohol, carboxymethyl cellulose, gum arabic, etc. As for the said organic binder, only 1 type may be used, and 2 or more types may be used.

As the above-mentioned inorganic binder, it is preferable to be in the form of particles that does not completely cover the surface of the above-mentioned inorganic silica-based porous material. Examples thereof include sodium silicate, silica sol, alumina sol, colloidal silica, Inorganic oxide particles such as colloidal alumina, colloidal tin oxide, colloidal titanium oxide, etc., among which colloidal silica, colloidal alumina, colloidal tin oxide, colloidal titanium oxide, etc. are preferred The inorganic oxide particles and so on. Among them, colloidal silica is preferred. As for the said inorganic binder, only 1 type may be used, and 2 or more types may be used.

The average particle diameter (primary particle diameter), specific surface area (BET specific surface area), average pore diameter (diameter), total pore volume, and the like of the inorganic binder are not particularly limited.

(Structure of chemical filter material)

The structure of the chemical filter material of the present invention is not particularly limited, and examples include honeycomb structure, pleated structure, pellet filling structure, three-dimensional mesh structure, sheet packaging structure, sheet structure, and the like. Among these, a honeycomb structure, a pleated structure, and a three-dimensional mesh structure are preferred, and from the viewpoint of suppressing pressure loss, a honeycomb structure is particularly preferred. Adsorption by pelletizing The use of the agent (pellet) as the adsorbent of the present invention is not particularly limited, but it is preferably a folded structure, a pellet filling structure, or a three-dimensional mesh structure. The chemical filter material of the present invention may have only one structure, or a combination of two or more structures.

The honeycomb structure mentioned above, in addition to the so-called honeycomb structure, also includes all fluids (especially air) whose cross-sections are lattice-shaped, circular, wavy, polygonal, indefinite, or shapes with curved surfaces in whole or in part can pass The structure of the nest that becomes the element of the structure.

The honeycomb structure includes, for example, a structure obtained by alternately laminating a corrugated sheet formed by corrugated processing and a flat sheet (corrugated honeycomb structure), a pleated sheet and a flat sheet. The structure formed by the sheet material is a structure formed by sequentially stacking folded sheets and flat sheets at right angles to the ventilation direction.

As the chemical filter material of the present invention having a honeycomb structure, for example, a fibrous substrate is used as the filter material base material, and the filter material base material has a chemical filter material having a wavy honeycomb structure; the filter material base material is a fibrous base material, and the filter material base The chemical filter material has a honeycomb structure; the metal filter material base material such as aluminum has a honeycomb structure.

The above-mentioned folding structure, for example, for the purpose of efficiently expanding the filtering area in a limited space, may include a structure having a bellows shape processed in a continuous manner in a wave or V shape.

The above-mentioned pellet filling structure may include, for example, a structure in which the above-mentioned pelletized adsorbent is filled in a housing with a structure in which fluid (especially gas) can pass through. In addition, the particle size of the adsorbent powder may not be pelletized if it has a particle size that can be retained in the shell. Granulation is made into a structure that directly fills the shell with powder as it is to replace the above-mentioned pellet filling structure.

The above-mentioned three-dimensional network structure may preferably include, for example, foams composed of the above-mentioned polyurethane foams, glass fibers (glass wool, etc.) or rock wool fibers, or those having the above-mentioned fibrous base material The structure of the filter material base material of the mesh structure produced by three-dimensional processing of fibers, or needle-like fiberized polytetrafluoroethylene, etc.

The above-mentioned sheet packaging structure includes, for example, a structure in which an air-ventilated sheet such as non-woven fabric or PTFE is formed into a bag of any size, and an adsorbent is filled inside. In addition, the particle size of the adsorbent may be such that the particles of the adsorbent are pelletized so as not to leak to the outside of the sheet, but it may be used as a powder depending on the photograph.

The sheet-like structure may include: a sheet of the resin composition (composition containing the adsorbent and resin of the present invention) formed into a bag-like structure of any size (bag body), or attached to the inner wall of the container On the structure (wallpaper), etc. In this case, the inside of the bag or container may be filled with an adsorbent or not. In the case of the sheet structure, for example, products (semiconductors, etc.) that need to be protected from contamination caused by siloxane compounds can be used as the chemical filter material of the present invention by putting them in a bag or container.

(The manufacturing method of the chemical filter material of the present invention)

The manufacturing method of the chemical filter medium of the present invention is not particularly limited, and a well-known or commonly used method for manufacturing a chemical filter medium with an adsorbent can be used. The chemical filter material of the present invention is not particularly limited, but, for example, it has at least the step of attaching the adsorbent of the present invention to the filter material base material (adhesion of adsorbent step). The manufacturing method of the chemical filter medium of the present invention is not particularly limited, but it may have steps (other steps) other than the adsorbent attachment step described above. In addition, the aforementioned filter medium base material can be purchased as a commercially available filter medium base material and used as it is.

In the adsorbent attaching step, the adsorbent of the present invention can be attached, for example, by immersing the filter substrate in a suspension containing the adsorbent of the present invention, a solvent (such as water, etc.), and if necessary the above-mentioned binder After the medium, it was taken out from the suspension and dried. The above-mentioned suspension may contain an anti-settling agent within a range that does not impair the effects of the present invention.

The attachment of the adsorbent of the present invention can also be achieved by immersing the filter material base material in a suspension containing the solvent and, if necessary, the binder, then taking it out of the suspension and drying, and then making the adsorbent of the present invention Disperse and adhere to the surface of the filter substrate.

The attachment of the adsorbent of the present invention can also be carried out by applying a mixed solution containing the adsorbent of the present invention, the above-mentioned solvent, and, if necessary, the above-mentioned binder, using a sprayer, etc., to apply and adhere to the above-mentioned filter substrate (especially non-woven fabric). ) And proceed.

The adhesion of the adsorbent of the present invention can also be such that pellets produced by granulating the powder of the adsorbent of the present invention can be attached to the filter material substrate with an adhesive or the like, or filled inside the filter material substrate. get on. When granulating the powder of the adsorbent of the present invention, the above-mentioned binder may be mixed as necessary. If the powder of the adsorbent of the present invention, the above-mentioned binder, and the solvent (preferably water) are mixed in a state that contains an appropriate amount of the adsorbent of the present invention, it will exhibit clay-like viscosity and plasticity and become capable of granulation.

The adhesion of the adsorbent of the present invention can also be used after The needle-shaped fiberized polytetrafluoroethylene resin is carried out by the needle-shaped fibers capturing and supporting the adsorbent of the present invention.

The adsorbent of the present invention can also be attached in a state where the adsorbent of the present invention is contained in nanofibers. As the aforementioned nanofibers, well-known or commonly used nanofibers can be used. In addition, the above-mentioned nanofibers can also be produced by well-known or commonly used nanofiber manufacturing methods. Examples of methods for producing the aforementioned nanofibers include electrospinning (ES) method (Electrospinning), meltblown method, composite melt spinning method, and the like. The above-mentioned ES method is performed by applying high voltage to a suspension of the adsorbent of the present invention dispersed in a polymer solution, and spraying it on a grounded surface (for example, a filter substrate (for example, non-woven fabric, etc.) with a surface of zero potential). In the above ES method, when the suspension is sprayed at a high voltage, nanofibers containing the adsorbent of the present invention are formed.

In addition, in the case of using a chemical filter medium for a filter medium base material (for example, a metal filter medium base material, etc.) to which an adsorbent is not easy to adhere, the adsorbent of the present invention can be attached to the filter medium base material using an adhesive.

In addition, in the chemical filter material of the above-mentioned pleated structure, the adhesion of the adsorbent of the present invention can also be carried out by, for example, using an adhesive, etc., to sandwich the powder or pelletized adsorbent of the adsorbent of the present invention. Between the non-woven filter material base material.

As the above-mentioned other steps, for example, a step of processing a filter medium base material (filter medium base material processing step) and the like. The order of the filter substrate processing step and the adsorbent attaching step is not particularly limited, but from the viewpoint of operability, the order of the filter substrate processing step and the adsorbent attaching step is preferred.

Examples of the processing step of the filter material base material include a step of applying wave processing to the filter material base material as described above, a step of forming a honeycomb structure, and a step of providing fine holes in the filter material base material. The above-mentioned filter material substrate processing steps can be performed one step at a time, or two or more steps of the same or different steps. In the case where the above-mentioned filter material substrate processing step is performed in two or more steps, the order is not particularly limited.

In addition, the chemical filter material of the present invention may also be a chemical filter material manufactured by a papermaking method. The chemical filter material produced by the above-mentioned papermaking method is, for example, a chemical filter material having at least a fibrous base material and the adsorbent of the present invention. The substance (floc) produced by adding a flocculant to the suspension is obtained by heat treatment after being thinned by wet papermaking.

Furthermore, the chemical filter material of the present invention may also be a ceramic type chemical filter material. The above-mentioned ceramic-type chemical filter material can be produced by a well-known or even commonly used ceramic material processing method. For example, the adsorbent of the present invention can be formed and fired together with ceramic raw materials to be manufactured. Specifically, for example, after weighing the adsorbent of the present invention, the above-mentioned binder, the pore-forming material, and other ceramic raw materials as necessary, and kneading to produce a clay, it is mixed by an extruder such as a screw extruder This clay is extruded to produce a shaped body. The obtained molded body is dried and fired to obtain a porous ceramic type chemical filter material. The ceramic-type chemical filter material is not particularly limited, but it is preferably a ceramic-type chemical filter material with a honeycomb structure. The above-mentioned ceramic-type chemical filter material can also be processed to a predetermined length with abrasive tools such as diamond cutters and diamond saws.

Among the above, the chemical filter material of the present invention is particularly preferably A chemical filter material with a honeycomb structure, wherein the honeycomb structure is formed by laminating a plurality of corrugated sheets with thin sheets interposed therebetween, and the corrugated sheets are formed by attaching the adsorbent of the present invention to the surface by an inorganic binder.

Although not particularly limited, in the chemical filter medium of the present invention, it is preferable that the adsorbent does not include an acidic substance-added additive. That is, in the chemical filter medium of the present invention, it is preferable not to use an adsorbent having an acidic substance-added additive.

(Framed)

The chemical filter material of the present invention is preferably used as a framed chemical filter material (framed chemical filter material). The above-mentioned framed chemical filter material is obtained by loading the chemical filter material (filtering material) of the present invention with the adsorbent of the present invention attached to the filter material base material into a frame. As the above-mentioned framed chemical filter material, for example, a panel type filter material, a cell type filter material, a chemical filter material for piping, etc. are mentioned. Among them, both the aforementioned filtering material and the aforementioned framed chemical filtering material correspond to the chemical filtering material of the present invention.

As the panel-type filter material, for example, a chemical filter material in which the edge of a plate-shaped filter material is fitted into the frame like a picture frame. The above-mentioned panel-type filter material is generally used in such a way that the fluid containing the silicone compound passes through the thickness direction of the plate-shaped filter material. The shape of the frame is not particularly limited, and can be appropriately selected according to the usage. Examples of the shape of the frame include: polygonal (for example, triangular, quadrangular, hexagonal, framed, etc.), round, elliptical, and polygonal shapes in which part or all of the corners are rounded, and these shapes Combination of shapes, etc. In addition, the above-mentioned plate-shaped filtering material may be used only in one piece, or a plurality of filtering materials may be stacked and used.

As the above-mentioned cell-type filter material, for example, a hexahedron-shaped (cube, rectangular parallelepiped, etc.) cell inside the cell, the fluid containing siloxane compound passes through the filter material, and the filter material is arranged . As the aforementioned cell-type filter medium, for example, a chemical filter medium in which the filter material has a series of bent portions so as to become a continuous V-shape, and the bent portions are arranged so as to face the ventilation direction. In addition, the cell-shaped filter material may be a chemical filter material arranged in a screen shape in a state where the respective bent portions are cut, that is, a plurality of filter materials have a V-shaped structure. In addition, in the cell-type filter material in which the filter material is arranged in a V-shaped structure, it is arranged so that the fluid containing the siloxane compound passes through the thickness direction of the filter material arranged in the V-shaped structure.

Examples of the above-mentioned chemical filter medium for piping include a chemical filter medium in which at least a part of the inside of a pipe having a cylindrical shape (for example, a cylindrical shape, a square cylindrical shape, etc.) is filled with a filtering material. In addition, in the portion filled with the filtering material, it is preferable to fill the entire section of the cylindrical pipe with the filtering material so that the fluid containing the silicone compound passes through the filtering material. The above-mentioned chemical filter material for piping can be preferably used for pressure piping.

The method of using the chemical filter material of the present invention includes, for example, the use of power such as a ventilation fan to forcibly introduce the air containing the target substance to the inside of the device equipped with the chemical filter material, in addition to the ventilation method for removing the target substance; There is a static method that does not use power to introduce air into a device equipped with a chemical filter, but only uses natural diffusion or natural convection contact to remove the target substance. That is, the chemical filter material of the present invention can be used in either the ventilation method or the static method use. As the above-mentioned ventilation method, for example, a unit that uses a ventilation fan (for example, a device for extracting air, a device for discharging air, etc.) integrated with the chemical filter material of the present invention (also called "Fan Filter Unit (Fan Filter Unit, FFU)”) method. In addition, the above-mentioned FFU can be installed on the ceiling or clean booth, or installed in the middle of the pipeline.

(Use environment of the chemical filter material of the present invention)

The chemical filter material of the present invention can be used in various environments where the chemical filter material can be used. For example, the chemical filter material of the present invention can be used even in environments such as high temperature environments where activated carbon cannot be used, various concentration environments, and humidity environments.

The chemical filter material of the present invention can be used in a wide range of temperature environments (for example, 0 to 500° C.). Chemical filter materials that use activated carbon as an adsorbent cannot be used because activated carbon will slowly oxidize in a high-temperature environment, thereby causing activation and expanding pores, reducing the removal performance. In addition, adsorbents that use organic substances such as resins cannot be used in high-temperature environments because the resin melts and catches fire in a high-temperature environment, or deteriorates in an environment exceeding 40°C. In contrast, since the chemical filter medium of the present invention does not need to use activated carbon as an adsorbent, it can be used in a wide temperature environment including a high temperature environment. The environmental temperature for using the chemical filter material of the present invention is not particularly limited, but is preferably 10 to 300°C, more preferably 15 to 100°C, and still more preferably 15 to 50°C.

Furthermore, chemical filter materials that use activated carbon as an adsorbent are estimated to have a tendency to decrease the removal efficiency of the silicone compounds due to activation of the molecular motion of the silicone compounds in a high-temperature environment. In contrast, the adsorbent of the present invention is mainly used to remove silicone compounds by chemical adsorption. So it can efficiently remove siloxane compounds even in high temperature environment.

The chemical filter material of the present invention can be used in a wide range of humidity environments (for example, in an environment with a relative humidity of 0 to 99% RH) within the range of no condensation. Therefore, the chemical filter material of the present invention can effectively remove siloxane compounds in the dry air. The relative humidity of the chemical filter material of the present invention is not particularly limited, but is preferably 10-95%RH, more preferably 30-90%RH, and still more preferably 35-70%RH.

In addition, when a zeolite with a pH of 7 or less is used as an inorganic silica-based porous material with a pH of 7 or less in the water mixture, the amount of hydrogen ions in the zeolite is large, and the amount of other cations is relatively small. It has relatively high performance, so it is not easy to absorb the moisture in the fluid even in a high humidity environment, and it is not easily affected by humidity. Therefore, siloxane compounds can be efficiently removed even in a high-humidity environment.

The chemical filter material of the present invention can be used in a wide range of pressure environments (for example, under an environment of 10 ^-11 ~ 100 MPa). The chemical filter material using activated carbon as the adsorbent increases the removal efficiency due to the higher concentration of the target substance under a high pressure environment. However, when the pressure returns to normal pressure, the excessively adhered substance tends to escape due to pressure. In contrast, the chemical filter material of the present invention strongly adheres to and removes the silicone compound, so it does not detach even when it returns to normal pressure after being used in a high-pressure environment. Therefore, the chemical filter material of the present invention can be used in a wide pressure environment including a high pressure environment. The environmental pressure in which the chemical filter material of the present invention is used is not particularly limited, but is preferably 10 ^-7 to 1 MPa, more preferably 10 ^-4 to 1 MPa, and still more preferably 0.05 to 1 MPa. Therefore, the chemical filter medium of the present invention can be preferably used even in a pressure pipe.

The chemical filter material of the present invention can be preferably used even in a wide range of siloxane compound concentration environments (for example, 0.001ppb~10ppm). In addition, the chemical filter medium of the present invention can efficiently remove the silicone compound even in an environment where the concentration of the silicone compound in the fluid is extremely low (for example, a single digit ppb or less). In particular, the chemical filter material of the present invention can be preferably used in an environment where the concentration of siloxane compounds in fluids (especially in the air) is 100 ppb or less (preferably 50 ppb or less, more preferably 10 ppb or less). under. In addition, although not particularly limited, the concentration of the siloxane compound in the fluid is preferably 0.001 ppb or more.

In addition, when the chemical filter material of the present invention is used in an environment where the concentration of the silicone compound in the fluid is extremely low, the temperature of the environment is not particularly limited, but is preferably 0 to 500°C, more preferably 15 to 50 ℃.

The chemical filter material of the present invention can be used in environments with various wind speeds (for example, the filter wind speed is 0-5 m/s). Especially, it can be used even in a high wind speed environment (for example, an environment where the filter wind speed is 1~5m/s). For chemical filter materials that use activated carbon as an adsorbent, the faster the wind speed of the passing air, the lower the removal efficiency. In contrast, the chemical filter material of the present invention can efficiently remove siloxane compounds even in a high wind speed environment. The wind speed of the environment in which the chemical filter material of the present invention is used is not particularly limited, but the filter wind speed is preferably 0~5m/s, more preferably the filter wind speed is 0~3m/s, and even more preferably the filter wind speed is 0~1m/s s.

In addition, the chemical filter medium of the present invention can be used even in an environment where the content of gases other than siloxane compounds is low (in a low gas environment) or in an environment where the air concentration is thin (for example, in a vacuum environment). Again, this hair Mingzhi chemical filter media does not need to use activated carbon as an adsorbent, so it can be better used in environments where flame retardancy is required.

The chemical filter material of the present invention is a chemical filter material used to remove silicone compounds. The siloxane compound is a compound having at least a Si-O-Si skeleton in the molecule. The silicone compound includes, for example, cyclic silicone compounds (for example, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, etc. D3~D20 Cyclic siloxane compounds, etc.), linear siloxane compounds (for example, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, etc.), the number of silicon atoms is 2 ~20 linear siloxane compounds, etc.), branched chain siloxane compounds, etc. Among them, cyclic siloxane compounds and linear siloxane compounds are preferred. In addition, the silicone compound is preferably one having volatility.

The chemical filter material of the present invention uses, as an adsorbent, an inorganic silica-based porous material whose water mixture has a pH of 7 or less. Therefore, in the chemical filter medium of the present invention, since the silanol group (-Si-OH) is present in the inorganic silica-based porous material acting as a solid acid, it is estimated that the solid acid will hydrolyze the siloxane compound , And make the compound form a silanol group. From this, it is speculated that the silanol group (-Si-OH) in the inorganic silica-based porous material and the silanol group produced by the hydrolysis of the siloxane compound in the fluid (especially in the air) undergo dehydration condensation. The Si-O-Si bond is formed, but the siloxane compound is strongly adsorbed and removed by chemical adsorption, and the once adsorbed siloxane compound becomes difficult to detach. In addition, compared to the case of using activated carbon, the bonding force between the inorganic silica-based porous material and the adsorbed siloxane compound is significantly stronger.

Like this, the chemical filter material of the present invention is mixed with water The inorganic silica-based porous material with a compound pH of 7 or less is used as an adsorbent to remove siloxane compounds. Therefore, unlike the case of using an adsorbent such as activated carbon, the siloxane compound once adsorbed will not be separated. Therefore, it is easier to estimate the adsorption capacity and easier to analyze the lifetime than the chemical filter material using activated carbon as the adsorbent. Also, as described above, since it is not easy to detach when returning from high pressure to normal pressure, it is also useful as a pressure piping.

In addition, the aforementioned Patent Documents 2 to 5 disclose the use of resins or porous materials into which acidic functional groups have been introduced to remove cyclic siloxane compounds. However, the sulfonic acid-based protic acid as the acidic functional group is completely different from the solid acid in inorganic silica-based porous materials such as zeolite. This is the same in the removal of siloxane compounds. In Patent Documents 2 to 5, the acidic functional group has a role of reacting siloxane compounds with each other. In contrast, in the present invention, as described above, the silanol group (-Si-OH) in the inorganic silica-based porous material and the silanol group produced by the hydrolysis of the siloxane compound are used for dehydration and condensation. Adsorption. In this way, the adsorption mechanism of the porous material into which the acidic functional group is introduced is completely different from that of the adsorbent of the present invention. In addition, in the case of using the chemical filter material of the present invention, since the reaction of siloxane compounds with each other is not required, even in an environment where the concentration of siloxane compounds in the fluid is extremely low, silicon can be removed efficiently Oxyane compounds.

In addition, in the aforementioned Patent Documents 2 to 5, resins or porous materials into which acidic functional groups are introduced are used. Therefore, in Patent Documents 2 to 5, a step of introducing acidic functional groups is necessary when producing chemical filter media. In particular, the steps of producing acidic compounds used in Patent Documents 3 and 4 Extremely complicated. In contrast, as the adsorbent of the present invention, it is not necessary to use resin or porous material into which acidic functional groups are introduced. Therefore, the chemical filter medium of the present invention does not need to be provided with a step of adding an acidic compound to a resin or porous material, a step of producing an acidic compound, and the like, and can be easily produced.

Furthermore, the chemical filter material that uses activated carbon as an adsorbent, in addition to siloxane compounds, there are other gas components such as organic gas components in the fluid. The removal of siloxane compounds is in a competitive relationship with the removal of the above organic gas components. . Therefore, the removal efficiency of the siloxane compound decreases. In contrast, as described above, the adsorbent of the present invention mainly removes siloxane compounds by the silanol group in the inorganic silica-based porous material, so it does not compete with the removal of the organic gas components. Relationship, can selectively and efficiently remove siloxane compounds.

[Fluid purification method]

In addition, by using the chemical filter material of the present invention to remove silicone compounds in the fluid, the fluid can be purified. In this way, the method of using the chemical filter material of the present invention to remove siloxane compounds in the fluid and purifying the fluid is also referred to as the "fluid purification method of the present invention". Therefore, the chemical filter material of the present invention can be used in appropriate places to remove siloxane compounds in fluids (such as air). For example, the chemical filter material of the present invention is particularly suitable for use as a chemical filter material in buildings such as general households and clean rooms, chemical filter materials in construction sites, chemical filters in sewage treatment plants, chemical filters in landfills, etc. It is required to remove siloxane compounds. As a chemical filter material in a clean room, it is particularly preferred as the internal chemical filter material of an exposure device , Coating the internal chemical filter material of the developing device, the chemical filter material surrounding the cutting process of the semiconductor wafer, and the chemical filter material surrounding the semiconductor manufacturing step.

In the above-mentioned clean room (for example, a clean room where gaseous pollutants are controlled, especially a clean room of a semiconductor manufacturing plant, etc.), there are various gaseous organic compounds such as siloxane compounds. Silicone compounds will adsorb on the surface of semiconductor silicon wafers and liquid crystal glass substrates, causing defects in these products. In addition, in the above-mentioned sewage treatment plant, the digested gas generated from the digestion tank contains a trace amount of siloxane compounds originating from the silicone oil contained in shampoo or cosmetics. Furthermore, in the above-mentioned landfills, siloxane compounds and silanol compounds contained in the biogas used in the buried soil (activated sludge, etc.) cause problems. Therefore, the chemical filter material of the present invention can be particularly preferably used in air purification for this purpose.

In addition, it can also be preferably used in gas sensors, reaction catalysts, etc., which need to avoid poisoning caused by siloxane compounds. It can also be used in the periphery of various analysis devices, gas supply lines, cell regeneration processing, micropore processing, and nuclear power plants. In addition, since the siloxane compound may lower the electromotive force of the fuel cell, it can also be preferably used in the manufacturing process of the fuel cell. Furthermore, siloxane compounds may accumulate in gas turbines, boiler burners, heat exchangers, etc., which may reduce efficiency, become a major cause of abnormalities or failures, and can therefore be used in such places.

In the case that the chemical filter material of the present invention can selectively remove siloxane compounds, the chemical filter material of the present invention, among the above, is particularly It is best used for gas sensor applications. In general households, etc., gas sensors are used as sensors (detectors) for detecting propane and butane. In this type of gas sensor, it is known that if a silicone compound adheres to the surface of the detection part, the sensitivity of the sensor is reduced, which will affect the detection capability. In order to prevent silicone compounds from adhering to protect the sensor, a filter material for adsorbing silicone compounds is installed on the gas sensor. Activated carbon is generally used as the adsorbent in the above-mentioned filter material, but the filter material using this kind of adsorbent adsorbs even the gas that must be detected by gas sensors such as propane and butane, and the gas sensor may be difficult to operate. . In contrast, the above-mentioned chemical filter material of the present invention can selectively remove siloxane compounds with high efficiency. Therefore, the chemical filter material of the present invention is particularly preferably used as a gas sensor application (preferably for an application installed on the upstream side of the detector in the gas sensor).

When the chemical filter material of the present invention is a chemical filter material for gas sensors, the chemical filter material of the present invention can be used in places where gas sensors can be used, such as general households, restaurants, kitchens, etc., among propane, butane, etc. Places where hydrocarbon gas may exist. More specifically, the chemical filter material of the present invention is preferably used by being installed directly in front of the gas detection part of the gas sensor. Other examples include a static method, in which the chemical filter material of the present invention is installed in the space where the gas sensor is installed, and the siloxane compound to be removed is removed only by the contact of natural diffusion and natural convection.

[Gas Sensor]

The chemical filter material of the present invention can be made into a gas sensor by being used inside a gas sensor. Gas equipped with the chemical filter material of the present invention The body sensor is also called "the gas sensor of the present invention". The gas sensor of the present invention is equipped with the chemical filter material of the present invention inside. In particular, the gas sensor of the present invention is preferably provided directly in front of the gas detection part. According to the gas sensor of the present invention, as the internal chemical filter material, the inorganic silica-based porous material with the pH of the water mixture below 7 is used as the adsorbent of the chemical filter material of the present invention. The gas sensor used as a chemical filter material for gas sensors in the past that uses activated carbon as an adsorbent can more efficiently remove siloxane compounds in the air. In particular, the removal efficiency of the siloxane compound will not be reduced in a short time, and the siloxane compound will not be released like activated carbon. Therefore, it is possible to significantly suppress the deterioration of the gas detection function of the gas sensor caused by the siloxane compound in the air. In addition, the adsorptivity of hydrocarbon gases such as propane and butane is low and does not hinder the operation of the gas sensor. Furthermore, since the siloxane compound is not separated from the adsorbent and the sensitivity of the sensor in the gas sensor is reduced, the malfunction of the sensor caused by the siloxane compound in the air can be significantly suppressed.

[Example]

Examples are given below to illustrate the present invention more specifically. However, the present invention is not limited in any way by these examples. Among them, "ppb" is based on weight unless otherwise specified.

Example 1

Use the ventilation test device shown in Figure 1 to measure the gas removal efficiency of the adsorbent. In Example 1, 6 sets of two acrylic cylindrical test pipe columns (inner diameter 50mm, length 30cm) 1 are connected in series and arranged in parallel, and the gas supply pipe 2 is installed Upstream of the string Install the flow meter 3, the flow adjustment valve 4, and the pump 5 on the downstream side of the pipe string in this order. A non-woven fabric 6 is sandwiched between the two pipe columns connected in series, and a 5 mm thick test sample (adsorbent) 7 is laid on the non-woven fabric 6, and the flow rate is adjusted so that the filter wind speed of the test sample becomes 5 cm/s to allow air to circulate. The air circulating in the column is used by mixing 200ppb octamethylcyclotetrasiloxane in the air adjusted to a temperature of 23°C and a humidity of 50% by a constant temperature and humidity tank. A schematic cross-sectional view (1 set) of the above-mentioned ventilation test device is shown in Fig. 2.

As the test sample (adsorbent), the water mixture shown in Table 1 (content ratio: 5wt%) has a plurality of zeolites with different pH, and the water mixture shown in Table 2 (content ratio: 5wt%) has a different pH Multiple types of silica gel, acid clay, activated clay and diatomaceous earth. The removal efficiency of 6 test samples is measured each time, and the 6 test samples to be measured are respectively used in each column 1 arranged in 6 groups in parallel. In addition, natural zeolite B is a citric acid treatment product of natural zeolite A. In addition, Silicone D is a hydrochloric acid treatment of Silicone A.

On the third day after the start of the ventilation test, the air on the upstream and downstream sides of the column was collected by the adsorption tube, and the adsorption tube with the collected air was delivered to ATD (thermal desorption device)-GC/MS for gas analysis and determination of octamethyl The gas concentration of cyclotetrasiloxane. From the measured gas concentration of octamethylcyclotetrasiloxane on the upstream and downstream sides of the column, the removal efficiency of octamethylcyclotetrasiloxane was calculated according to the following formula, and the pH and pH of the water mixture of the test sample Diagram of the relationship between removal efficiency.

Removal efficiency (%)={(gas concentration on the upstream side-gas concentration on the downstream side)/gas concentration on the upstream side)×100

The results are shown in Table 1, Table 2, Figure 3 (zeolite), and Figure 4 (silicone , Acid clay, diatomaceous earth). In Figure 4, the square (□) represents the data of silica gel, the triangle (△) represents the data of acid clay, the circle (○) represents the data of activated clay, and the cross (×) represents the data of diatomaceous earth. The horizontal axis of the graph is the pH of the water mixture of the test sample, and the vertical axis is the removal efficiency (%).

[Determination of Loss on Ignition]

In addition, the loss on ignition (%) in Table 2 was obtained by the following method.

First, the sample (inorganic silica-based porous material) to be evaluated is spread out thinly in a petri dish and placed in a constant temperature and humidity chamber for 1 day. The mass of the subsequent sample is measured and set as the "sample quality". Then, for the inorganic silica-based porous material that has been allowed to stand for one day, a differential thermal/thermogravimetry simultaneous measurement device (trade name "TG/DTA 6200", manufactured by Hitachi High-Tech Science Co., Ltd.) is used. Thermogravimetry (TG) was performed to measure the mass after keeping at 170°C for 2 hours and the mass after keeping at 1000°C for 2 hours. The above-mentioned mass after keeping at 170°C for 2 hours is referred to as the "sample mass after drying", and the above-mentioned mass after keeping at 1000°C for 2 hours is referred to as "the sample mass after burning".

Then, using the obtained mass of the sample after drying and the mass of the sample after combustion, the loss on ignition is calculated according to the above formula (1). Table 3 shows the results of the mass of the sample after drying, the mass of the sample after combustion, and the loss on ignition.

As shown in Table 1, Table 2, Figure 3, and Figure 4, inorganic silica-based porous materials such as zeolite, silica gel, activated clay, and diatomaceous earth whose water mixture has a pH of 7 or less are compared to The inorganic silica-based porous material with the pH of the water mixture greater than 7, the removal of octamethylcyclotetrasiloxane The removal efficiency is significantly greater.

Comparative example 1

Except for using an acidic ion exchange resin (containing a sulfonic acid group) as a test sample (adsorbent), the same procedure as in Example 1 was carried out, and the gas removal efficiency of the adsorbent was measured using the ventilation test device shown in Fig. 1.

On the third day after the start of the ventilation test, the air on the upstream and downstream sides of the column was collected by the adsorption tube, and the adsorption tube with the collected air was delivered to ATD (thermal desorption device)-GC/MS for gas analysis and determination of octamethyl The gas concentration of cyclotetrasiloxane. From the measured gas concentration of octamethylcyclotetrasiloxane on the upstream and downstream sides of the column, the removal efficiency of octamethylcyclotetrasiloxane was calculated according to the following formula.

Removal efficiency (%)={(gas concentration on the upstream side-gas concentration on the downstream side)/gas concentration on the upstream side)×100

As a result, the removal efficiency of octamethylcyclotetrasiloxane in the case of using acidic ion exchange resin was 0%.

Example 2

For some test samples after the ventilation test of Example 1, an extraction test with acetone was performed. A part of the above-mentioned test samples were put into 30 ml of acetone solvent and shaken for 2 hours. After that, the supernatant was delivered to GC-FID for analysis. Table 4 shows the area value of octamethylcyclotetrasiloxane measured by GC-FID. In addition, as a comparison object, coconut shell activated carbon (manufactured by FUTAMURA CHEMICAL CO., LTD., trade name "Taihe CB", pH of water mixture: 10.17), and acid-added activated carbon (the coconut shell activated carbon is added with For potassium bisulfate, the additive amount relative to activated carbon: 6 wt%, pH of water mixture: 2.61), chemical activation activity Carbon (chemical-activated carbon) (manufactured by FUTAMURA CHEMICAL CO., LTD., trade name "Taihe S", pH of water mixture: 4.48) was used as the adsorbent, and the same ventilation test as in Example 1 was carried out. Similarly, the area value of octamethylcyclotetrasiloxane measured by GC-FID is shown in Table 4. In addition, the area value shown in Table 4 is a value when the area value of coconut shell activated carbon is set to 100 (calculated by volume).

As shown in Table 4, although in the case of coconut shell activated carbon, acid-added activated carbon, and chemically activated activated carbon, the adsorbed octamethylcyclotetrasiloxane will be extracted by acetone, but the pH of the water mixture In the case of inorganic silica-based porous materials such as zeolite, silica gel, activated clay, and diatomaceous earth below 7, the adsorbed octamethylcyclotetrasiloxane will not be extracted by acetone. It can be seen that, compared to activated carbon, octamethylcyclotetrasiloxane is an inorganic silica-based porous material with a pH of 7 or less that is very strongly adsorbed to a water mixture.

Example 3

A part of the test samples (zeolite D, zeolite I, silica gel B, activated clay A, and diatomaceous earth A) after the completion of the ventilation test of Example 1 were respectively subjected to gel permeation chromatography analysis. 0.5 g of the above test sample and 1 g of tetrahydrofuran (THF) were mixed and subjected to elution treatment, and after filtration, the molecular weight was measured by gel permeation chromatography. In other words, a column filled with filler (showdex KE-806M 804 802, Showdex KE-806M 804 802, Showdex KE-806M 804 802, Showdex KE-806M 804 802, Showdex KE-806M 804 802, manufactured by Tosoh Co., Ltd.) Manufacture), using THF (THF without stabilizer, manufactured by Wako Pure Chemical Industries, Ltd.) as the eluent, and the measurement was performed at 1.0 mL/min at a column temperature of 40°C. As a result, although a peak with a weight average molecular weight of several hundreds was detected, a peak with a weight average molecular weight of several hundreds of thousands which was larger than this was not detected.

From the results, it can be seen that the adsorbent of the present invention does not polymerize and adsorb siloxane compounds as in the inventions described in Patent Documents 2 and 5, but makes inorganic silica-based porous materials and siloxane compounds directly React and remove.

Example 4

The same procedure as in Example 1 was carried out except that 60 ppb of decamethyltetrasiloxane air mixed with air adjusted to a temperature of 23°C and a humidity of 50% in a constant temperature and humidity tank was used as the air circulating in the column. , Use the ventilation test device shown in Figure 1 to measure the gas removal efficiency of the adsorbent. In addition, as the test sample (adsorbent), plural zeolite and diatomaceous earth having different pHs of the water mixture (content ratio: 5 wt%) shown in Table 5 were used.

On the third day after the start of the ventilation test, the air on the upstream and downstream sides of the column was collected by the adsorption tube, and the adsorption tube that collected the air was delivered to ATD (Thermal Desorption Device)-GC/MS for gas analysis to determine the decamethyl group The gas concentration of tetrasiloxane. From the measured gas concentration of decamethyltetrasiloxane on the upstream and downstream sides of the column, the removal efficiency of decamethyltetrasiloxane is calculated by the following formula, and the relationship between the pH of the water mixture and the removal efficiency of the test sample The chart.

Removal efficiency (%)={(gas concentration on the upstream side-gas concentration on the downstream side)/gas concentration on the upstream side)×100

The results are shown in Table 5 and Figure 5. In Figure 5, the diamond shape (◇) represents zeolite The cross (×) indicates the data of diatomaceous earth. The horizontal axis of the graph is the pH of the water mixture of the test sample, and the vertical axis is the removal efficiency (%).

As shown in Table 5 and Figure 5, inorganic silica-based porous materials such as zeolite and diatomaceous earth with a pH of 7 or less in the water mixture are compared to inorganic silica-based porous materials with a pH of more than 7 in the water mixture. The removal efficiency of decamethyltetrasiloxane is obviously greater.

Example 5

The same procedure as in Example 1 was performed except that air mixed with 100 ppb of n-hexane and 100 ppb of toluene in air adjusted to a temperature of 23°C and a humidity of 50% in a constant temperature and humidity tank was used as the air circulating in the column. Use the ventilation test device shown in Figure 1 to measure the gas removal efficiency of the adsorbent. In addition, as the test sample (adsorbent), a plurality of inorganic silica-based porous materials with different pHs of the water mixture (content ratio: 5 wt%) shown in Table 6 were used.

On the third day after the start of the ventilation test, the air on the upstream and downstream sides of the column was collected by the adsorption tube, and the adsorption tube that collected the air was delivered to the ATD (thermal desorption device)-GC/MS for gas analysis, and the n-hexane and The respective gas concentration of toluene. From the measured gas concentrations of n-hexane and toluene on the upstream and downstream sides of the column, the removal of individual gas components is calculated by the following formula Efficiency, make a graph of the relationship between the pH of the water mixture of the test sample and the removal efficiency.

Removal efficiency (%)={(gas concentration on the upstream side-gas concentration on the downstream side)/gas concentration on the upstream side)×100

The results are shown in Table 6.

As shown in Table 6, when an inorganic silica-based porous material with a water mixture pH of 7 or less is used, the removal efficiency of organic compounds such as n-hexane and toluene is relatively low. Therefore, siloxane compounds can be selectively removed.

Example 6

(Manufacturing of chemical filter material for sheet packaging structure)

100 parts by weight of the olefin-based thermoplastic resin was put into a metal container set on a hot plate set at 150°C, and the adsorbent was put little by little while stirring the resin put in the container. After putting all the adsorbent in the container, stirring was continued for about 5 minutes to obtain a resin composition in which the resin and the adsorbent were uniformly mixed (kneaded). Then, in a petri dish of Φ65 mm, the obtained resin composition is stretched thinly so that the weight of the resin becomes 5 g to form a sheet. In addition, diatomaceous earth A (100 parts by weight), synthetic zeolite I (100 parts by weight), and silica gel B (20 parts by weight) were used as adsorbents to produce three types of sheets.

(Evaluation of adsorption capacity)

Without removing the three kinds of sheets obtained above from the petri dish, put the three petri dishes and the petri dish containing 1.5 g of octamethylcyclotetrasiloxane into a metal airtight container. Let stand for 3 days in an environment of ℃. Then, the weight of the petri dish before and after the standing was measured, and the difference was set as the adsorption amount of octamethylcyclotetrasiloxane. The result is shown below.

Diatomaceous earth A: 0.072g

Synthetic zeolite I: 0.067g

Silicone B: 0.091g

[Industrial availability]

The chemical filter material of the present invention can be used in appropriate places to remove siloxane compounds in fluids (for example, air). For example, the chemical filter material of the present invention can be particularly preferably used as a chemical filter material in buildings such as general households and clean rooms, chemical filter materials in construction sites, chemical filter materials in sewage treatment plants, chemical filters in landfills, etc. It is required to remove siloxane compounds. As the chemical filter material in the clean room, particularly preferred are the internal chemical filter material of the exposure device, the internal chemical filter material of the coating and developing device, the chemical filter material surrounding the cutting process of semiconductor wafers, and the chemical filter material surrounding the semiconductor manufacturing process.

Claims (21)

A chemical filter material for the removal of siloxane compounds, which uses an inorganic silica-based porous material as an adsorbent. The inorganic silica-based porous material is mixed with pure water without adding an additive to obtain a water mixture The pH (content ratio: 5 wt%) is 7 or less. For example, the chemical filter material for the removal of silicone compounds in claim 1, wherein the inorganic silica-based porous material is selected from the group consisting of zeolite, silica gel, alumina silica, aluminum silicate, porous glass, and diatom Soil, hydrated magnesium silicate clay minerals, allophane, filiform bauxite, acid clay, activated clay, activated bentonite, mesoporous silica, aluminum silicate (aluminosilicate) , And at least one or more inorganic silica-based porous materials from the group of fumed silica. For example, the chemical filter material for the removal of silicone compounds in claim 1, in which as the adsorbent, an inorganic silica-based porous material with a pH of 7 or less of the water mixture (content ratio: 5wt%) and other adsorbents are used at the same time . The chemical filter material for the removal of siloxane compounds according to claim 1, wherein the inorganic silica-based porous material contains at least 10% by weight relative to the total weight of the adsorbent, selected from synthetic zeolite and diatomaceous earth One or more of the group of, silicone, and activated clay. For example, the chemical filter material for removing siloxane compounds in claim 1, which contains synthetic zeolite as the inorganic silica-based porous material, and the ratio of SiO ₂ to Al ₂ O ₃ in the synthetic zeolite (mole ratio) [ SiO ₂ /Al ₂ O ₃ ] is 4~2000. For example, the chemical filter material for the removal of siloxane compounds in claim 1, wherein the inorganic silica-based porous material contains synthetic zeolite with a ring number of 10-12. For example, the chemical filter material for the removal of siloxane compounds in claim 1, wherein the inorganic silica-based porous material includes a synthetic zeolite with a 2- to 3-dimensional pore channel system. For example, the chemical filter material for the removal of silicone compounds in claim 1, which contains synthetic zeolite as the inorganic silica-based porous material, and the synthetic zeolite is selected from ferrierite, MCM-22, ZSM-5, ZSM -11. At least one framework structure of the group of mordenite, Beta type, X type, Y type, and potassium zeolite. For example, the chemical filter material for removing siloxane compounds of claim 1, wherein the inorganic silica-based porous material is an inorganic silica-based porous material with a loss on ignition of 7.0% or less obtained by the following formula (1) , Loss on ignition I(%)=(W ₁ -W ₂ )/W ₁ ×100. . . (1) W ₁ : The mass of the sample after drying W ₂ : The mass of the sample after combustion [Equation (1), the mass of the sample after drying (W ₁ ) is the inorganic silica-based porous material in the air about 170 The mass of the inorganic silica-based porous material after heating for 2 hours at ℃ or under vacuum at about 150°C; the mass of the sample after combustion (W ₂ ) is the inorganic silica-based porous material of the dried sample Mass of inorganic silica-based porous material obtained by burning at 1000℃±50℃ for 2 hours]. The chemical filter material for removing silicone compounds according to any one of claims 1 to 9, wherein the chemical filter material is attached to the adsorbent by a binder For the filter substrate. The chemical filter material for removing silicone compounds according to claim 10, wherein the binder is a binder having a pH of 7 or less in a water mixture (content ratio: 5 wt%) obtained by mixing with pure water. Such as the chemical filter material for the removal of silicone compounds in claim 10, wherein the binder is colloidal inorganic oxide particles. The chemical filter material for removing silicone compounds according to any one of claims 1 to 9, wherein the structure of the chemical filter material has a structure selected from the group consisting of a honeycomb structure, a pleated structure, a three-dimensional mesh structure, a sheet packaging structure, and a sheet structure The structure of at least one of the groups. The chemical filter material for removing silicone compounds according to any one of claims 1 to 9, wherein the chemical filter material for removing silicone compounds comprises the adsorbent that has been pelletized. The chemical filter material for removing silicone compounds according to claim 14, wherein in the pelletizing, a binder with a pH of 7 or less of a water mixture (content ratio: 5 wt%) obtained by mixing with pure water is used. The chemical filter material for removing silicone compounds according to any one of claims 1 to 9, wherein the chemical filter material for removing silicone compounds does not use a binder and attaches the adsorbent to the filter material base material. A resin composition, which is a resin composition used in the chemical filter material for removing siloxane compounds according to any one of claims 1 to 9, comprising the inorganic silica-based porous material and resin. For example, the chemical filter material for removing silicone compounds of claim 3, which is a chemical filter material that attaches the adsorbent to the filter material substrate by a binder, and has a structure selected from the group consisting of honeycomb structure, pleated structure, three-dimensional mesh structure, and sheet The structure of at least one of the group of material packaging structure and sheet structure, as the inorganic silica-based porous material, includes the ratio of SiO ₂ to Al ₂ O ₃ (mole ratio) [SiO ₂ /Al ₂ O ₃ ] is 4~2000 having at least one skeleton selected from the group consisting of ferrierite, MCM-22, ZSM-5, ZSM-11, mordenite, Beta type, X type, Y type, and potassium zeolite The structure of synthetic zeolite, the binder is colloidal inorganic oxide particles, and the water mixture (content ratio: 5wt%) obtained by mixing with pure water has a pH of 7 or less. The chemical filter material for removing siloxane compounds according to claim 3, wherein the inorganic silica-based porous material contains at least 10% by weight relative to the total weight of the adsorbent, which is obtained by the following formula (1) One or more selected from the group consisting of synthetic zeolite, diatomaceous earth, silica gel, and activated clay with a loss on ignition of 7.0% or less, loss on ignition 1(%)=(W ₁ -W ₂ )/W ₁ ×100 . . . (1) W ₁ : The mass of the sample after drying W ₂ : The mass of the sample after combustion [Equation (1), the mass of the sample after drying (W ₁ ) is the inorganic silica-based porous material in the air about 170 The mass of the inorganic silica-based porous material after heating for 2 hours at ℃ or under vacuum at about 150°C; the mass of the sample after combustion (W ₂ ) is the inorganic silica-based porous material of the dried sample Mass of inorganic silica-based porous material obtained by burning at 1000°C±50°C for 2 hours]. The chemical filter material for removing silicone compounds according to claim 19, wherein the structure of the chemical filter material has a structure selected from the group consisting of a honeycomb structure, a pleated structure, a three-dimensional mesh structure, a sheet packaging structure, and a sheet structure At least one structure. A resin composition, which is the resin composition used in the chemical filter material for removing silicone compounds according to claim 20, and includes the inorganic silica-based porous material and resin.

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