JP2003088759A - Low temperature oxidation catalyst filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect the activity of a catalyst from contaminants contained in a binder poisoning a low-temperature oxidation catalyst or an additive during processing, and maintain the activity of the catalyst in a high state for a long time. It is an object of the present invention to provide a low-temperature oxidation catalyst, a low-temperature oxidation catalyst sheet, and a low-temperature oxidation catalyst filter having a function of performing the following. The metal adsorbent is selected from a metal oxidation catalyst comprising 0.1 to 20% of a metal used as an oxidation catalyst in a porous adsorbent at a low temperature, and a hydroxide or carbonate of an alkali metal or an alkaline earth metal. A low-temperature oxidation catalyst containing one kind, a low-temperature oxidation catalyst filter carrying the same on a substrate, and a low-temperature oxidation catalyst filter formed by pleating or honeycomb processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low temperature oxidation catalyst for decomposing and removing malodorous components, and in particular, by combining a metal oxidation catalyst and an alkaline substance, attachment of contaminants such as binders exposed during filter processing. The present invention relates to a deodorizing filter that can be used for a long period of time while suppressing a decrease in catalyst activity due to

[0002]

2. Description of the Related Art Malodorous gas components that have been present in the living environment such as refrigerators, houses, and automobiles are amines and mercaptans derived from foods and people, ammonia contained in cigarette smoke, lower aldehydes, Known are lower carboxylic acids, SO ₂ , NO _x , hydrocarbons, etc., which are derived from the exhaust gas of combustion engines.

Against these bad odors, since the bad odor prevention law was promulgated in 1972, the administrative measures against bad odors have been in full swing, and the deodorizing technology has been advanced accordingly. In recent years, deodorizers for refrigerators have become widespread, and deodorizers and deodorants for toilets and entrances have come to appear in order to make living spaces comfortable, and it seems that air conditioners such as air conditioners will also be equipped with deodorizers. Became.

Known deodorizing methods include a chemical absorption method, a direct combustion method, a catalytic oxidation method, an ozone oxidation method, a masking method and an adsorption deodorization method. Of these, the adsorption deodorization method is the most widely used method.

However, in the conventional adsorptive deodorization method, when an odorous substance is adsorbed on the adsorbent, it reaches saturated adsorption relatively early, and therefore it is very difficult to maintain the deodorizing ability of the adsorbent for a long time. There were challenges. For example, when activated carbon or the like is used alone as an adsorbent, the performance life is short and it is difficult to remove all malodorous components. Further, if an acidic substance or an alkaline substance is impregnated and carried on activated carbon or the like, the range of the malodorous components that can be removed is expanded, but it is not effective for all malodorous components, and if these are impregnated and carried, There is also a problem that the life of the adsorbent is shortened.

Under such circumstances, when a semiconductor such as a metal oxide or a metal sulfide called a photocatalyst is irradiated with light, electrons having a strong reducing action and holes having a strong oxidizing action are generated. A method of regenerating the deodorant by adding a photocatalyst to the adsorbent, which decomposes molecules contacting the semiconductor, is disclosed in JP-A-1-234729 and JP-A-1-23.
It is disclosed in Japanese Patent No. 1926 and Japanese Patent Laid-Open No. 9-75434.

[0007] In the conventional method, the adsorbent is regenerated by completely oxidizing and decomposing the adsorbed malodorous component using a photocatalyst. However, general adsorbents (eg, activated carbon, zeolite,
(Silica gel, silica gel, etc.) with a catalyst attached or supported, there is a problem that the decomposition rate is very slow with respect to the adsorption rate.

Under the above circumstances, a catalyst for oxidizing and decomposing malodorous molecules in the space by utilizing a catalyst having an oxidative decomposition activity at a low temperature such as a noble metal is disclosed in Japanese Patent Laid-Open No. 2000-3127.
It was disclosed in Japanese Patent No. However, when using these catalysts as air purification parts, contact between the oxidation catalyst and organic contaminants such as binders is unavoidable, and the catalyst is poisoned before being processed into a filter shape. There was a problem that it would end up.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the catalyst which is oxidatively decomposed at a low temperature. Therefore, the low temperature oxidation catalyst has been poisoned so far when it is processed into honeycomb or pleats. A low-temperature oxidation catalyst that has effective deodorizing performance by protecting the catalytic activity from contaminants contained in binders and additives and by producing a catalyst that has higher initial properties as a material carrier than before. A low temperature oxidation catalyst sheet and a low temperature catalyst filter are provided.

[0010]

As a result of intensive studies to solve the above problems, the present inventor has invented a low temperature oxidation catalyst, a low temperature oxidation catalyst sheet using the same, and a low temperature oxidation catalyst filter. .

(1) A metal oxidation catalyst containing 0.1 to 20% by mass of a metal used as an oxidation catalyst at room temperature in a porous adsorbent, and a hydroxide or carbonate of an alkali metal or an alkaline earth metal. And a low temperature oxidation catalyst containing at least one thereof.

(2) A low temperature oxidation catalyst sheet in which the low temperature oxidation catalyst according to claim 1 is supported on a substrate.

(3) A low temperature oxidation catalyst filter in which the low temperature oxidation catalyst sheet of claim 2 has a honeycomb structure or a pleated structure.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The constituent elements of the external deodorizing filter for an air conditioner of the present invention will be described. First, the structure of the low temperature oxidation catalyst according to the first aspect of the present invention will be described in detail.

A typical example of the porous adsorbent according to the present invention is activated carbon. This is because activated carbon is porous and exhibits high adsorption performance, and it is easy to control activation of the average maximum radius and the specific surface area, and the production cost is low. Here, as a raw material of the activated carbon, a palm shell or a carbide of wood is preferable. Examples of the activation method include a steam activation method, an activation method performed at high temperature with carbon dioxide gas, and a chemical activation method using zinc chloride or phosphoric acid. As the raw material of the porous adsorbent, activated carbon is optimal as described above, but it is also possible to use zeolite, silica gel, activated alumina and activated clay.

The activated carbon preferably has an adsorbed amount of benzene per mass of 25 to 60% by mass. This is because if it is less than 25% by mass, sufficient adsorption force cannot be secured, and if it exceeds 60% by mass, the malodorous component may be released again.

Examples of the metal used as the oxidation catalyst at room temperature according to the present invention include platinum, palladium, rhodium, ruthenium, iridium, osmium, and any mixture thereof. Since these odorous components can be oxidatively decomposed at room temperature, they do not require a light source like a photocatalyst and are said to be maintenance-free and maintain their effects. The example shown here is an example, and the catalyst is not particularly limited to the above substances as long as it is a catalyst capable of performing a redox reaction in a room temperature range. Here, room temperature is approximately -30 ° C.
It refers to up to -50 ° C, which is a temperature range that can be obtained without using temperature control. As a matter of course, the case of maintaining and setting within the temperature range by using a temperature control device is included in the meaning of normal temperature.

A method for incorporating a metal used as an oxidation catalyst at room temperature into a porous adsorbent will be described. In the present invention, the metal is impregnated or supported by 0.1 to 20 mass% with respect to the porous adsorbent. If it is less than 0.1% by mass, the amount of the metal supported is too small to expect the desired activity, and if it exceeds 20% by mass, the area covering the surface of the adsorbent becomes large and high catalytic activity cannot be expected. Many of the metals to be supported are generally called noble metals, and it is economically disadvantageous to have a high content, so the activity itself is effective within the above range, but preferably 0. A content of 1-5% is good. The distribution of the metal in the porous adsorbent is preferably uniform over the entire surface including pores, but it may be localized or may be a mixture.

Examples of the alkali metal or alkaline earth metal hydroxide or carbonate according to the present invention include sodium hydrogen carbonate, sodium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide and the like. However, the present invention is not particularly limited to these, and all substances capable of obtaining the effect of maintaining the activity of the low temperature oxidation catalyst filter of the present invention are included here.

The content of the above-mentioned alkali metal or alkaline earth metal hydroxide or carbonate is preferably in the range of 1% by mass to 20% by mass with respect to the total mass of the low temperature oxidation catalyst. If the amount is less than 1% by mass, the effect of preventing poisoning of the low temperature oxidation catalyst becomes low, and if it exceeds 20% by mass, the area covering the surface of the adsorbent becomes large and a high adsorption capacity cannot be obtained, and the crystal is not formed. This is because it causes precipitation and causes problems such as powder falling from the filter.

Although there are low-temperature catalysts which do not contain hydroxides or carbonates of alkali metals or alkaline earth metals, when this material is used as a deodorizing filter, various low-temperature catalysts used during processing into filters are used. There is a problem that the catalyst surface is poisoned by the additive and the performance actually obtained at the single material level cannot be obtained,
The fact is that the performance of most filters with a low-temperature oxidation catalyst has been deactivated by the time they reach the hands of ordinary consumers.

By blending the above-mentioned alkali metal or alkaline earth metal hydroxide or carbonate in the above-mentioned use amount range, not only the degradation of the decomposition activity of the low-temperature oxidation catalyst can be suppressed but also the low-temperature oxidation catalyst itself can be suppressed. Since the rate of functional deterioration is also reduced, it has become possible to adjust the catalyst for long-term use. The reason why these effects are obtained is considered to be, in addition to the ion exchange action of the above substances, a washing effect of the organic intermediate product which is oxidatively decomposed and attached / accumulated on the surface of the low temperature oxidation catalyst.

In order to bring out the effect of maintaining the catalytic activity of the present invention to a greater extent, the shape of the porous adsorbent is preferably a particle having a diameter of 1 mm or less. It may be difficult to contain, and it may be difficult to obtain high activity. Further, it is preferable that the alkali metal or alkaline earth metal hydroxide or carbonate is uniformly used on the entire surface including the pores of the metal oxidation catalyst, but it is locally used as a part of the metal oxidation catalyst. It may be liquefied or a mixture.

Next, the low temperature oxidation catalyst sheet according to the second aspect of the present invention will be described in detail.

Examples of the base material according to the present invention include woven cloth, non-woven cloth, net, urethane foam, sponge, polyethylene film, polypropylene film,
In addition, a general-purpose thermoplastic film such as a polyester film, a thin plate and the like can be mentioned. Among these, a sheet having poor air permeability such as a film or a thin plate may have fine holes to improve air permeability. Among them, especially when a non-woven fabric or the like is used, not only is it possible to ensure a relatively uniform air permeability, but also encapsulation processing is easy, so that it is used predominantly. Further, if the catalyst is applied to a metal plate or the like and is used under a condition where it can be overheated, the activity of the catalyst is further increased, which is effective.

The non-woven fabric includes polyamide fiber, polyester fiber, polyalkylene paraoxybenzoate fiber, polyurethane fiber, polyvinyl alcohol fiber, polyvinylidene chloride fiber, polyvinyl chloride fiber, polyacrylonitrile fiber, polyolefin fiber. , Synthetic fiber such as phenolic fiber, glass fiber, metal fiber, alumina fiber, inorganic fiber such as activated carbon fiber,
It is produced by various methods using natural fibers such as wood pulp, hemp pulp, cotton linter pulp, regenerated fibers, or fibers obtained by imparting hydrophilicity or flame retardancy to these fibers.

The method for producing the nonwoven fabric is not particularly limited, and the web obtained by a dry method, a wet papermaking method, a melt blow method, a spunbond method or the like can be hydroentangled, needle punched or stitched depending on the purpose and application. Physical methods such as the bonding method, thermal bonding methods such as the thermal bonding method,
It can be manufactured by appropriately combining the methods of expressing strength by an adhesive method such as a resin bond.

When a low temperature oxidation catalyst is internally added to a base material such as a non-woven fabric as one of the methods for supporting on a sheet, for example, it is produced by adding the low temperature oxidation catalyst together with the material of the base material when manufacturing the base material. As a result, the filter agent used in the low temperature oxidation catalyst filter of the present invention can be manufactured. At this time, a cationic polymer flocculant such as a cationic polyacrylic amide or polyaluminum chloride, or an anionic polymer flocculant such as an anionic polyacrylic amide that forms a complex with the flocculant and strengthens the aggregation. It is preferable to form an aggregate by using an anionic inorganic fine particle such as an agent, colloidal silica or bentonite. Alternatively, it is possible to further improve the mechanical strength of the aggregate by including the fine fibers in the aggregate.

On the other hand, when a low temperature oxidation catalyst is applied to a substrate such as a non-woven fabric, as a binder for fixing the low temperature oxidation catalyst to the substrate, an aqueous emulsion of a thermoplastic resin, a film-forming inorganic substance, Metal oxide composite thermoplastic polymer emulsions, etc., individually or in combination as required, are mixed with a low temperature oxidation catalyst to produce various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, short dwell coaters. , Die coater, comma coater, reverse roll coater, kiss coater, dip coater, curtain coater, extrusion coater, microgravure coater, size press, etc. Can make oxidation catalyst filter Kill.

Here, the aqueous emulsion of the thermoplastic resin refers to a thermoplastic polymer dispersed in water, and the polymer component includes an acrylic resin, a styrene-acrylic copolymer and a styrene-butadiene copolymer. , Ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl chloride copolymer,
Examples thereof include polypropylene, polyester, phenoxy resin, phenol resin, butyral resin and the like.

Here, the metal oxide composite thermoplastic polymer emulsion has a shape in which the surface of the thermoplastic polymer emulsion is covered with a metal oxide, and the polymer component and the metal oxide are formed even after the film is formed. It has the property that the components are separated to maintain the sea-island structure.

Examples of the metal oxide include colloidal silica and colloidal alumina. Metal oxide composite thermoplastic polymer emulsions, such as colloidal silica composite thermoplastic polymer emulsions, are disclosed in JP-A-59 / 1999.
As disclosed in JP-A-71316 and JP-A-60-127371, a copolymerizable monomer, a monomer having a polymerizable unsaturated double bond and an alkoxysilane group in the molecule, or vinylsilane. , A colloidal silica is mixed and the polymer component is emulsion-polymerized to be produced, and the silica component is fixed on the emulsion surface. As the method, for example, International
al Symposiumon Polymeric
Microspheres Prints, 1991,
181, a method of depositing and fixing a silica component on the surface of an emulsion previously formed using a water-insoluble hydrolyzable alkoxysilane such as ethyl orthosilicate.

In addition to the addition and fixing of the low-temperature oxidation catalyst to the above-mentioned base material by coating or coating, it is suitable within the range not impairing the flexibility required for the low-temperature oxidation catalyst filter of the present invention. Wet methods such as plating and sol-gel methods, resistance heating vacuum deposition methods, electron beam heating vacuum deposition methods, ion plating methods, vacuum deposition methods such as sputtering methods, and anodic oxidation methods on various substrates. The low temperature oxidation catalyst may be supported and fixed by a known method. Furthermore,
In order to further improve the deodorizing performance, it may be attached to the porous adsorbent. For example, in order to adsorb an aldehyde gas, an adsorbent having an amino group is used, or in order to adsorb a basic gas, an adsorbent in which a hydroxyl group is distributed on the surface of the porous adsorbent is considered, By carrying out these treatments, a synergistic effect with the catalytic activity can be expected.

Next, the low temperature oxidation catalyst filter according to the third aspect of the present invention will be described in detail.

The honeycomb according to the present invention is a structure composed of cell walls having openings, is excellent in air permeability, can increase the surface area per unit volume, and is a preferable structure for the low temperature oxidation catalyst filter of the present invention. Is. Specific examples of such a honeycomb include a corrugated honeycomb formed by stacking single-faced corrugated board manufactured according to “exterior corrugated board” described in JIS-Z-1516, a hexagonal honeycomb including hexagonal cells, and a square cell. And a honeycomb formed of triangular cells, a honeycomb formed by assembling hollow cylindrical cells, and the like. Here, the cell shape such as a hexagon or a square is not a formal polygon but may be an irregular shape with rounded corners or curved sides.

The corrugated honeycomb corrugated shape is
Generally, it is a sine wave or a pseudo sine wave, but is not particularly limited, and may be a wave such as a sea wave, a triangular wave, a square wave, a semicircle or a fan-shaped wave. Further, without departing from the spirit of the present invention, the step height of the middle shin may not be constant, and at least a part of the top of the middle shin may be out of contact with the liner.

The honeycomb according to the present invention is disclosed in JP-A-11-
As disclosed in Japanese Patent No. 244708, corrugated blocks are produced by stacking and adhering single-sided corrugated board,
A corrugated honeycomb in which the liner surface has an oblique angle with respect to the opening surface of the cell, which is manufactured by obliquely cutting the liner surface of the corrugated block at a constant angle, may be used. The diagonal angle is not particularly limited,
30-60 degree is preferable.

The pleating process according to the present invention is a ridge-valley fold process, and the area of the filter substrate can be increased for a given ventilation area. The shape of the pleats is not particularly limited, and may be appropriately set according to the area and thickness of the base material used, but the height (H) of the ridges and the pitch (P ) And H / P = 2 to 20
It is preferable to satisfy the relationship of. If H / P is less than 2, the increase in the area of the base material is small. On the other hand, if H / P is greater than 20, the surfaces of the adjacent base materials are too close to each other, which may impair the air permeability.

Although the constituent elements of the present invention have been described in detail above, regarding the low temperature oxidation catalyst sheet and the low temperature oxidation catalyst filter of the second and third inventions of the present invention, the low temperature oxidation catalyst is not necessarily uniform on the sheet. Does not need to be distributed in the sheet, and may be locally present in a part of the sheet or the filter as long as the effect of the present invention can be obtained.

[0040]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these as long as the gist thereof is not exceeded.

Preparation Example 1 of Metal Oxidation Catalyst 1 As a porous adsorbent, 10 g of coconut shell activated carbon was mixed with 400 ml of absolute ethanol and 0.2 mol of hexachloroplatinum (IV).
Stir well with 10 ml of acid solution and add 1m at room temperature.
50 ml of aqueous sodium borohydride solution is added.
After a few minutes, 40 ml of a 6 mol hydrochloric acid solution was added to decompose excess sodium borohydride to obtain a metal oxidation catalyst A.
At this time, the amount of platinum supported on the metal oxidation catalyst A was 5% by mass.

Preparation Example 2 of Metal Oxidation Catalyst 2 1% palladium chloride solution and water (50 ml) were added to 10 g of alumina as a porous adsorbent and boiled for 15 minutes, and 20 ml of formalin and 0.05N sodium carbonate 1
5 ml was added, and the mixture was boiled for another 15 minutes, then allowed to cool, the catalyst was separated by centrifugation, washed with water, and then dried at 50 ° C. to obtain a metal oxidation catalyst B. At this time, the amount of palladium supported on the metal oxidation catalyst was 5% by mass.

Preparation Example 1 of Substrate 50% by mass of polyester fiber (fineness 3d, fiber length 38 mm), polyester fiber (fineness 6 d, fiber length 51 mm)
30% by mass and viscose rayon fiber (3d, 51 m
m) 20% by mass and mixed to form a web by a dry method, and then impregnated in acrylic latex which is a thermoplastic binder and dried to obtain a highly breathable dry nonwoven fabric substrate A. It was made.

Preparation Example 2 of Base Material Core-sheath type heat-fusible polyester fiber (fineness 2d, fiber length 5)
mm) 50% by mass, polyester fiber (fineness 0.5d,
Fiber length 5 mm) 45% by mass, softwood bleached kraft pulp (Canadian standard freeness 480 ml) 5% by mass was added and mixed in water, and basis weight 100 g / m ² using a cylinder paper machine.
A base material B of the wet non-woven fabric was prepared.

Example 1 After stirring 9.8 g of the metal oxidation catalyst A and 0.2 g of sodium hydrogen carbonate in 100 g of water in the above preparation example, the catalyst was separated by centrifugation and dried at 50 ° C. It was used as a low temperature oxidation catalyst.

Example 2 After stirring 9.8 g of the metal oxidation catalyst B and 0.2 g of sodium carbonate in 100 g of water in the above preparation example, the catalyst was separated by centrifugation and dried at 50 ° C. It was used as a low temperature oxidation catalyst.

Example 3 70% by mass of the low temperature oxidation catalyst of Example 1 and 30% by mass (in terms of active ingredient) of a vinyl acetate-ethylene-acrylic emulsion (Sumitomo Chemical Industries, Ltd., Sumikaflex-900) were added. To adjust the coating liquid, 30g of this coating liquid
The low temperature oxidation catalyst sheet of Example 3 was obtained by impregnating and coating the base material A in the above preparation example with a dry coating mass of / m ² .

Example 4 70% by mass of the low temperature oxidation catalyst of Example 2 and 30% by mass (in terms of active ingredient) of a vinyl acetate-ethylene-acrylic emulsion (Sumitomo Chemical Co., Ltd., Sumikaflex-900) were added. To adjust the coating liquid, 30g of this coating liquid
The low-temperature oxidation catalyst sheet of Example 4 was obtained by impregnating and coating the base material B in the above-mentioned preparation example with a dry coating weight of / m ² .

Example 5 The low temperature oxidation catalyst sheet of Example 3 was applied to 120 mm × 120 m
A low temperature oxidation catalyst filter of Example 5 was obtained by pleating with a size of m × 10 mm and a pitch of 3 mm.

Example 6 The low temperature oxidation catalyst sheet of Example 4 was applied to 120 mm × 120 m
A low temperature oxidation catalyst filter of Example 6 was obtained by processing a corrugated honeycomb with a size of m × 10 mm at 50 cells / inch.

Examples 7 and 8 In the low temperature oxidation catalyst filter of Example 5, the metal oxidation catalyst A of the above-mentioned preparation example was used in which the amount of platinum supported was 0.1%, and the amount of platinum supported was 20%. Was used as the low temperature oxidation catalyst filter of Example 8.

Comparative Example 1 The deoxidizing catalyst of Comparative Example 1 was used as the metal oxidation catalyst A in the above Preparation Example.

Comparative Example 2 9.8 g of activated carbon in a palm shell and 0.2 g of sodium hydrogen carbonate
After stirring in 100 g of water, the catalyst was separated by centrifugation and dried at 50 ° C. to obtain the deodorizing catalyst of Comparative Example 2.

Comparative Example 3 The deoxidizing catalyst of Comparative Example 3 was used as the metal oxidation catalyst B in the above Preparation Example.

Comparative Example 4 9.8 g of alumina and 0.1 g of sodium hydroxide were added to 10 parts of water.
After stirring in 0 g, the catalyst was separated by centrifugation and
It was dried at 0 ° C. to obtain a deodorizing catalyst of Comparative Example 4.

Comparative Example 5 70% by mass of the deodorizing catalyst of Comparative Example 1 and 30% by mass (in terms of active ingredient) of a vinyl acetate-ethylene-acrylic emulsion (Sumitomo Chemical Co., Ltd., Sumikaflex-900) were added. To prepare a coating liquid, and the coating liquid was impregnated and coated on the base material A in the above-mentioned preparation example at a dry coating weight of 30 g / m ² to obtain a deodorizing catalyst sheet of Comparative Example 5.

Comparative Example 6 70% by mass of the deodorizing catalyst of Comparative Example 2 and 30% by mass (converted into active ingredient) of a vinyl acetate-ethylene-acrylic emulsion (Sumitomo Chemical Co., Ltd., Sumikaflex-900) were added. To prepare a coating solution, and the coating solution was impregnated and coated on the base material A in the above-mentioned preparation example at a dry coating weight of 30 g / m ² to obtain a deodorizing catalyst sheet of Comparative Example 6.

Comparative Example 7 The deodorizing catalyst sheet of Comparative Example 5 was 120 mm × 120 mm ×
A deodorizing catalyst filter of Comparative Example 7 was obtained by pleating with a size of 10 mm and a pitch of 3 mm.

Comparative Example 8 The deodorizing catalyst sheet of Comparative Example 6 was 120 mm × 120 mm ×
A deodorizing catalyst filter of Comparative Example 8 was obtained by processing a corrugated honeycomb with a size of 10 mm and 50 cells / inch.

Comparative Examples 9 and 10 Comparative Example 9 in which the platinum loading amount of the metal oxidation catalyst A of the above-mentioned preparation example was 0.03% in the low temperature oxidation catalyst filter of Example 5 and the loading amount of platinum was 25%. Was used as the low temperature oxidation catalyst filter of Comparative Example 10.

Next, the performance of the filters of Examples and Comparative Examples will be described. In addition, when performing the test of the filters, the conditions were adjusted so that the total amount of the low-temperature oxidation catalyst or the deodorizing catalyst contained in the sample was 3 g, and then the evaluation was performed.

[Deodorization Performance Test] Formaldehyde as a malodorous gas component is injected into a 1 m ³ stainless steel chamber with a gas tight syringe and adjusted to 15 ppm. After confirming that the concentration of the system became steady, the sample was brought into contact with a gas to perform a deodorization test, and the concentration was measured 3 hours after the start of the test to obtain the removal rate.

[Durability Performance Test] After carrying out the above deodorization test, the sample was left in clean air for 48 hours, and again subjected to the deodorization test in a 1 m ³ stainless steel chamber. The test was continuously performed 5 times, and the removal rate was calculated from the concentration 3 hours after the start of the 5th test, and the result was taken as the durability performance.

[0064]

[Table 1]

From the results shown in Table 1, the low temperature oxidation catalyst filter using a hydroxide or carbonate of an alkali metal or an alkaline earth metal as a metal oxidation catalyst as in the samples of Examples has not only initial deodorizing performance but also durability. The performance continues to be effective. Since the samples of Comparative Examples 1, 3, 5, 7, 9, and 10 did not use the alkali metal or alkaline earth metal hydroxide or carbonate, which is the feature of the present invention, in addition to the metal oxidation catalyst, The activity is lower than that of the samples of Examples. Among these, sheet processing (Comparative Example 5), pleats, corrugated honeycomb processing (Comparative Examples 7, 9 and 10)
The performance of the sample subjected to the above test was further deteriorated, and the deodorization performance had already disappeared at the initial performance stage. From this result, by using a hydroxide or carbonate of an alkali metal or an alkaline earth metal in the constitution of the present invention, the activity sustaining effect of the low temperature oxidation catalyst is expressed, and when not used, the performance is remarkably improved during the filter processing. However, it is considered that the same level of performance as before processing was obtained. On the other hand, the deodorizing catalyst filters of Comparative Examples 2, 4, 6, and 8 use a porous adsorbent and an alkali metal or alkaline earth metal hydroxide or carbonate, but the porous adsorbent has a catalyst. Formaldehyde was significantly lower than the samples of the examples due to the initial deodorizing performance, since the sulphate was not supported. Furthermore, in Comparative Example 9, the activity was not obtained because the amount of the metal used as the oxidation catalyst was too small, and in Comparative Example 10, since the amount of the catalyst supported was too large, the surface area was rather reduced to reduce the activity. It was observed. To summarize the above results, in the low temperature oxidation catalyst filter of the present invention, a metal oxidation catalyst is used in combination with an alkali metal or alkaline earth metal hydroxide or carbonate to activate the catalyst surface and A filter having a function of improving deodorizing performance and a function of protecting a catalytically active site from a substance which is easily poisoned such as an organic binder which is exposed during filter processing and having a function of maintaining a long-term effect can be produced. .

[0066]

INDUSTRIAL APPLICABILITY The low temperature oxidation catalyst filter of the present invention has a higher activity in a room temperature environment by containing a metal-supporting porous adsorbent with an alkali metal or alkaline earth metal hydroxide or carbonate. In addition, a long-life catalyst function can be imparted.

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Claims (3)

[Claims] 1. A metal oxidation catalyst comprising a porous adsorbent containing 0.1 to 20 mass% of a metal used as an oxidation catalyst at room temperature, and an alkali metal or alkaline earth metal hydroxide or carbonate. A low-temperature oxidation catalyst containing at least one kind. 2. A low temperature oxidation catalyst sheet in which the low temperature oxidation catalyst according to claim 1 is supported on a base material. 3. A low temperature oxidation catalyst filter in which the low temperature oxidation catalyst sheet according to claim 2 has a honeycomb structure or a pleated structure.