JPH10137329A - Air purifying film and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the decomposing activity of an odor component adsorbed to a coating film surface and suppress the desorption of aldehyde having low adsorptive performance by providing a lower film containing an adsorbent, or an optical catalyst and the adsorbent, and an upper film covering the lower film and containing the optical catalyst in a quantity larger to the adsorbent than the lower film. SOLUTION: An air purifying film is formed of a bed film 2 formed on the surface of a base 1, and an overcoat film 3 formed on the surface thereof. Each of the films 3, 2 contains an adsorbent 4, an optical catalyst 5 and a binder 6, and the optical catalyst 5 of the overcoat film 3 is contained in a quantity larger than the optical catalyst 5 of the bed film 2. Thus, the decomposing performance by the optical catalyst 5 in the overcoat film 3 surface and the critical surface between the film 3 and the bed film 2 is enhanced to raise the decomposing performance of the adsorbed component and the regenerating performance of the adsorbent 4, so that the adsorptive performance can be kept for a long time. Since the odor component adsorbed by the bed film 2 is necessarily passed through the overcoat film 3 even if desorpted from the adsorbent 4, the odor can be efficiently decomposed by ultraviolet rays.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane for purifying odors contained in air, and more particularly, to a membrane containing NOx as an odor component.
And air containing organic compounds and the like.

[0002]

2. Description of the Related Art As a conventional deodorizing apparatus using a photocatalyst, a composite of activated carbon and a photocatalyst has been proposed as disclosed in JP-A-5-293165, which is shown in FIG. Show.

In FIG. 12, a filter 102 for blocking light from a light source and an ultraviolet lamp 1 for exciting a photocatalyst are shown.
03, adsorption activated carbon 104 with photocatalyst, and blowing means 105
Are arranged in series in this order. After operating the blower 105 for a predetermined time, the blower 105 is stopped, the light source is turned on for a predetermined time, the activated activated carbon 104 with photocatalyst is reactivated, and then the power supply is automatically cut off.

With the above structure, the ultraviolet light lamp 103 is used to excite the photocatalyst on the surface of the activated carbon with photocatalyst 104, and the photocatalyst decomposes the odor component adsorbed by the activated carbon with photocatalyst 104.

[0005]

However, in the above-mentioned conventional air purification coating film, the adsorption activated carbon 104 with a photocatalyst is used.
If a film consisting only of a photocatalyst is formed on the surface of an adsorbent such as, the adsorption performance of the photocatalyst for odor components differs depending on the type of photocatalyst. Particularly, titanium dioxide decomposes aldehydes as intermediate products when decomposing odor components. Is generated,
There has been a problem that aldehydes desorb from the surface of titanium oxide and are released into the air.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to improve the activity of decomposing odor components adsorbed on the surface of a coating film by a photocatalyst, and at the same time, to suppress the desorption of aldehydes having a low adsorption performance with a photocatalyst. It is intended to provide a purification membrane.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an adsorbent or a base film (lower film) in which a photocatalyst and an adsorbent are combined to form a photocatalyst at a lower mixing ratio than the lower film. This is a multi-layer air purification film on which a large overcoat film (upper film) is formed. First, the coating liquid for the base film is applied to a sheet of various materials serving as a base material or a gas-permeable carrier such as a honeycomb, and dried and baked to form a base film. Further, a coating solution for an overcoat film using high silica synthetic zeolite H-type ZSM5, which has been subjected to a copper ion exchange treatment as an adsorbent, is applied to the base film, dried and baked to form a multilayer air purification coating film. . The dirt component of the air that comes into contact with this film is adsorbed, and the film is irradiated with ultraviolet light to excite the photocatalyst and decompose the adsorbed component.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the air purification membrane of the present invention will be described with reference to the drawings. In the embodiment of the air purification film of the present invention, an overcoat film (upper film) is formed on the surface of a base film (lower film).

In order to determine an appropriate mixing ratio of the photocatalyst and the adsorbent in the overcoat film of the air purification film of the present invention,
Various layers were formed by changing the mixing ratio of the photocatalyst and the adsorbent. As a photocatalyst, titanium oxide ST-01 manufactured by Ishihara Sangyo Co., Ltd. is used. As an adsorbent, high silica synthetic zeolite H type ZSM5 subjected to a copper ion exchange treatment is used. Binder, Bettac No 970GD
Kai (product name) was used.

The solid content ratio (weight ratio) of the binder is set to 50%, and the solid content ratio of the sum of the photocatalyst and the adsorbent is set to 50%.
And the ratio between the photocatalyst and the adsorbent was within a range of 50%.
Are variously changed as shown in FIG.
m) aluminum corrugated honeycomb (200 cells / inc)
Samples A to D were prepared by applying 200 (g / l) to the surface of h ² ) and baking at 380 ° C. for 1 hour.

[0011]

[Table 1]

After placing these samples in a 1 (m ³ ) box and purging dry clean air to remove odors and the like, five mild sevens were simultaneously burned in the box, and the air flow was 0.94 (m ³ ). m ³ / min), the sample was irradiated with ultraviolet light 3.4 (mW / cm) while performing air purification.
² ), and the deodorizing performance of liacetaldehyde (shown in FIG. 1) and NOx (shown in FIG. 2) was measured by a gas detector tube.

As shown in FIG. 1, the residual ratio of acetaldehyde was reduced most rapidly in sample B, and then the residual ratio of acetaldehyde was kept low in samples A and C, but in sample D, the adsorbent was not used. Since it did not contain, acetaldehyde generated from the photocatalyst by decomposition of the odor was separated from the catalyst film. This indicated that Sample D without adsorbent was unsuitable. In addition, as shown in FIG. 2, the larger the ratio of the photocatalyst to the adsorbent, the faster the residual rate of nitric oxide decreased. However, sample A
The sample A was found to be unsuitable because about 10% of nitric oxide remained even after 100 minutes. From the results shown in FIGS. 1 and 2, the ratio of the photocatalyst to the adsorbent suitable for the overcoat film is 1: 9 to 1:49.
It turned out to be.

Summarizing the above results, the deodorizing performance of acetaldehyde is low with the photocatalyst alone, and if acetaldehyde is generated as an intermediate during decomposition of the odor component, the acetaldehyde is released from the photocatalyst.
However, as shown in FIG. 1, by adding an adsorbent to the photocatalyst (samples A to C), the release of acetaldehyde into the air can be suppressed, and the ratio of the adsorbent to the photocatalyst is 1: 1. (Sample A) contains nitric oxide (NO
Since the deodorizing performance of x) is low, the deodorizing performance of NOx can be improved and the residual ratio of acetaldehyde can be reduced by adjusting the mixing ratio of the photocatalyst and the adsorbent to 1: 9 to 1:49.

Hereinafter, an embodiment of the air purification film of the present invention in which an overcoat film (upper film) is formed on the surface of a base film (lower film) based on the data of the ratio between the photocatalyst and the adsorbent will be described. explain.

The same photocatalyst, adsorbent and binder are used as described above. First, a coating solution for a base film was prepared in which the solid content ratio (weight ratio) of the photocatalyst was 25%, the solid content ratio of the adsorbent was 25%, and the solid content ratio of the binder was 50%. Is applied to the surface of the aluminum corrugated honeycomb to be 200 (g / l) to be 380
The substrate was baked at 1 ° C. for 1 hour to form a base film.

Furthermore, the solid content ratio of the photocatalyst is 49%, the solid content ratio of the adsorbent is 1%, and the solid content ratio of the binder is 50% (that is, the solid content ratio is 50%).
A coating solution for the overcoat film of sample C) is prepared, and the coating solution is overcoated on the surface of the undercoat film and baked at 380 ° C. for 1 hour to form an air composed of the overcoat film and the undercoat film. Purification membrane samples EG were prepared.
Samples E to G were obtained by changing the weight ratio of the overcoat film to the base film as shown in Table 2.

[0018]

[Table 2]

FIG. 3 shows a film structure of an air purification film in which an overcoat film is formed on the surface of a base film. In FIG.
The structure of the air purification film is such that a base film 2 is formed on the surface of a base material 1 and an overcoat film 3 is formed on the surface of the base film 2. The overcoat film 3 and the base film 2 include the adsorbent 4, the photocatalyst 5, and the binder 6, respectively. The photocatalyst 5 included in the overcoat film 3 is more than the photocatalyst 5 included in the base film 2. Many are included.

The above-mentioned samples EG were placed in a box of 1 (m ³ ), and after purging dry clean air,
Simultaneously burn five mild sevens, air volume 0.94
Each sample was irradiated with ultraviolet light 3.4 (mW / cm ² ) while purifying air at (m ³ / min), and acetaldehyde (FIG. 4), NOx (FIG. 5), carbon monoxide ( FIG. 6), styrene (FIG. 7), acetic acid (FIG. 8),
The deodorizing performance (decomposition performance) of ammonia (FIG. 9) and pyridine (FIG. 10) was measured.

As shown in FIG. 4, the residual ratio of acetaldehyde in Samples E and F decreased with time, but in Sample G, the residual ratio of acetaldehyde became constant over time. As shown in FIG.
Samples E and F showed good values of the residual ratio of nitric oxide representative of Ox, but in Sample G, 30% or more of nitric oxide remained even at 100 minutes.

As shown in FIG. 6, the residual ratio of carbon monoxide was not significantly different in any of Samples E, F and G. FIG.
As shown in Table 2, the residual ratio of styrene decreased with time in Samples E and F, but in Sample G, the residual ratio of styrene became constant over time. As shown in FIGS. 8, 9, and 10, the residual ratios of acetic acid, ammonia, and pyridine did not differ significantly among samples E, F, and G, respectively.

From the above results, the carrying ratio (weight ratio) of Samples E and F, that is, the overcoat film and the base film.
When the ratio was 1: 2 to 1: 4, various odors could be adsorbed and decomposed.

As shown in FIG. 11, the selection of the adsorbent was made on the assumption that the adsorbent had a high adsorption performance for acetaldehyde having a low decomposition efficiency by the photocatalyst, and the high silica synthetic zeolite H-type ZSM5 was subjected to a copper ion exchange treatment. ZS
M5 was used.

[0025]

According to the first aspect of the present invention, the air purifying film of the present invention has the above-mentioned structure, so that the photocatalytic decomposition performance at the surface of the upper film and at the interface between the upper film and the lower film is enhanced, and the adsorption is improved. The ability to decompose the components and regenerate the adsorbent is increased, and the adsorption performance can be maintained for a long time. Further, the odor component adsorbed on the lower film always passes through the upper film even if it is desorbed from the adsorbent, so that the odor can be efficiently decomposed by ultraviolet rays.

According to the second aspect, by controlling the ratio of the photocatalyst to the adsorbent in the upper film, the adsorption performance of the aldehyde components having low adsorption performance by the photocatalyst alone can be enhanced in the lower film. To prevent desorption from the air purification membrane. In addition, the photocatalyst contained in the upper film makes it possible to deodorize NOx, which was difficult to deodorize with the adsorbent alone.

According to the third aspect, by controlling the weight ratio between the upper film and the lower film, the amount of adsorption on the lower film is increased.

According to the fourth aspect, since the adsorption performance of aldehydes having low adsorption performance with the photocatalyst alone is improved, the mixing ratio of the photocatalyst to the adsorbent can be increased, and the decomposition efficiency can be improved.

According to the fifth aspect, an air purification membrane capable of adsorbing and decomposing various odors can be manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing acetaldehyde purification performance by a single layer film in which the ratio between a photocatalyst and an adsorbent is changed for the present invention.

FIG. 2 is an explanatory view showing a nitrogen oxide purification performance by a single layer of FIG. 1;

FIG. 3 is a sectional view showing a film structure of an embodiment of the air purification film of the present invention.

FIG. 4 is an explanatory view showing acetaldehyde purification performance according to an embodiment of the air purification membrane of the present invention.

FIG. 5 is an explanatory diagram showing nitric oxide purification performance according to an embodiment of the air purification membrane of the present invention.

FIG. 6 is an explanatory diagram showing carbon monoxide purification performance according to an embodiment of the air purification membrane of the present invention.

FIG. 7 is an explanatory diagram showing styrene purification performance according to an embodiment of the air purification membrane of the present invention.

FIG. 8 is an explanatory diagram showing acetic acid purification performance according to an embodiment of the air purification membrane of the present invention.

FIG. 9 is an explanatory diagram showing ammonia purification performance according to an embodiment of the air purification film of the present invention.

FIG. 10 is an explanatory diagram showing pyridine purification performance according to an embodiment of the air purification membrane of the present invention.

FIG. 11 is an explanatory diagram showing a comparison of acetaldehyde adsorption performance in a dry state of the air purification membrane of the present invention.

FIG. 12 is a configuration diagram showing a conventional deodorizing apparatus using a photocatalyst.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Undercoat film 3 Overcoat film 4 Adsorbent 5 Photocatalyst 6 Binder

Claims (5)

[Claims] 1. An adsorbent or a lower film containing a photocatalyst and an adsorbent, and an upper film covering the surface of the lower film and containing a photocatalyst larger than the lower film with respect to the adsorbent. An air purification membrane characterized by the following. 2. The air purification membrane according to claim 1, wherein the upper membrane has a weight ratio of the adsorbent to the photocatalyst of 1: 9 to 1:49. 3. The weight ratio of the lower film and the upper film is 1:
The air purification membrane according to claim 1, wherein the ratio is 2 to 1: 4. 4. The air purification membrane according to claim 1, wherein the adsorbent is obtained by subjecting zeolite to a copper ion exchange treatment. 5. A coating solution containing an adsorbent or a photocatalyst and an adsorbent is applied to a substrate, and heated to form a lower film. On the surface of the lower film, the lower film reacts with the adsorbent. A method for producing an air purification film, which comprises applying a coating liquid containing a large amount of a photocatalyst and then heating to form an upper film.