Air purifying film and its manufacture

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a membrane that purifies an odor contained in air, and particularly purifies air containing NOx, an organic compound, or the like as an odor component.

【0002】

[Conventional technology]

As a conventional deodorizing device using a photocatalyst, as disclosed in Japanese Patent Application Laid-Open No. 5-293165, a composite of activated carbon and a photocatalyst has been proposed, and this is shown in FIG.

【0003】

In FIG. 12, a filter 102 that blocks light from a light source, an ultraviolet lamp 103 that excites a photocatalyst, an adsorption activated carbon 104 with a photocatalyst, and a blower 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 adsorption activated carbon 104 with a photocatalyst is reactivated, and then the power supply is automatically cut off.

【0004】

With the above configuration, the photocatalyst on the surface of the adsorbed activated carbon 104 with a photocatalyst is excited by using the ultraviolet lamp 103, and the odor component adsorbed by the adsorbed activated carbon 104 with a photocatalyst is decomposed by the photocatalyst.

【0005】

[Problems to be Solved by the Invention]

However, in the above-mentioned conventional air purification coating film, if a film containing only a photocatalyst is formed on the surface of an adsorbent such as an adsorption activated carbon 104 with a photocatalyst, the adsorption performance of the photocatalyst for odorous components differs depending on the type of photocatalyst. In particular, in titanium oxide, when aldehydes are generated as intermediate products when decomposing odorous components, there is a problem that the aldehydes are desorbed from the surface of titanium oxide and released into the air.

【0006】

The present invention solves the above problems, and provides an air purification film that improves the decomposition activity of odorous components adsorbed on the surface of a coating film by a photocatalyst and at the same time suppresses the desorption of aldehydes having low adsorption performance by a photocatalyst. The purpose is to provide.

【0007】

[Means for solving problems]

In order to solve the above problems, in the present invention, an overcoat film (upper film) having a larger compounding ratio of the photocatalyst than the lower film is provided on the surface of the adsorbent or the base film (lower film) in which the photocatalyst and the adsorbent are combined. It is a formed multi-membrane air purification film. First, the coating liquid of the base film is applied to a sheet of various materials as a base material or a breathable carrier such as a honeycomb, and dried and baked to prepare a base film. Furthermore, an overcoat film coating solution using high silica synthetic zeolite H-type ZSM5 that has been subjected to copper ion exchange treatment as an adsorbent is applied onto the undercoat film, dried, and baked to form a multi-layer air purification coating film. .. The pollutant component of the air that comes into contact with the film is adsorbed, and the film is irradiated with ultraviolet rays to excite the photocatalyst and decompose the adsorbed component.

【0008】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments relating to 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 the undercoat film (lower film).

【0009】

In order to obtain an appropriate compounding ratio of the photocatalyst and the adsorbent in the overcoat film of the air purification film of the present invention, the compounding ratio of the photocatalyst and the adsorbent was variously changed to form a single layer film. Titanium oxide ST-01 manufactured by Ishihara Sangyo Co., Ltd. is used as the photocatalyst, high silica synthetic zeolite H-type ZSM5 subjected to copper ion exchange treatment is used as the adsorbent, and colloidal silica-based manufactured by Ternic Kogyo Co., Ltd. as the binder. Binder, Betac No970GD Kai (trade name) was used.

【0010】

In addition, the solid content ratio (weight ratio) of the binder is 50%, the solid content ratio of the sum of the photocatalyst and the adsorbent is 50%, and the ratio of the photocatalyst and the adsorbent is within the range of 50%, as shown in Table 1. 200 x 90 x t20 (mm) aluminum corrugated honeycomb (200 cells / inch) with various changes as shown² ) Was applied to the surface at 200 (g / l) and baked at 380 ° C for 1 hour to prepare samples A to D.

【0011】

[table 1]

<img file="JPH10137329A_D0001.tif" />【0012】

1 (m) of these samples³ ), After purging dry clean air to remove odors, burn 5 Mild Seven at the same time in the box, and the air volume is 0.94 (m).³ With / min), UV light 3.4 (mW / cm) is applied to the sample while purifying the air.² ) Was irradiated, and the deodorizing performance of lyacetaldehyde (shown in Fig. 1) and NOx (shown in Fig. 2) was measured with a gas detector tube.

【0013】

As shown in FIG. 1, the residual rate of acetaldehyde decreased fastest in sample B, and then samples A and C kept the residual rate of acetaldehyde low, but sample D did not contain an adsorbent. , Acetaldehyde generated from the photocatalyst due to the decomposition of odor was released from the catalyst membrane. From this, it was found that the sample D containing no adsorbent was inappropriate. Further, 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, it was found that sample A was inappropriate because about 10% of nitric oxide remained in sample A even after 100 minutes had passed. From the results shown in FIGS. 1 and 2, it was found that the ratio of the photocatalyst to the adsorbent suitable for the overcoat film was 1: 9 to 1:49.

【0014】

Summarizing the above results, since the deodorizing performance of acetaldehyde is low with the photocatalyst alone, if acetaldehyde is produced as an intermediate product during the decomposition of the odorous component, the acetaldehyde is separated 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. Since the deodorizing performance of nitric oxide (NOx) is low in (Sample A), the deodorizing performance of NOx can be improved and the residual acetaldehyde remains by adjusting the mixing ratio of the photocatalyst and the adsorbent to 1: 9 to 1:49. I was able to reduce the rate.

【0015】

Hereinafter, embodiments of the air purification film of the present invention in which an overcoat film (upper film) is formed on the surface of the undercoat film (lower film) will be described based on the above-mentioned data on the ratio of the photocatalyst and the adsorbent.

【0016】

The same photocatalyst, adsorbent, and binder as described above are used. First, a coating liquid for an undercoat 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%, and this coating liquid was used as a base material. It was applied to the surface of the aluminum corrugated honeycomb to be 200 (g / l) and baked at 380 ° C for 1 hour to form a base film.

【0017】

Further, a coating solution for an overcoat film having a photocatalyst solid content ratio of 49%, an adsorbent solid content ratio of 1%, and a binder solid content ratio of 50% (that is, sample C) was prepared, and this coating solution was used as an undercoat film. The surface was overcoated and baked at 380 ° C for 1 hour to prepare samples E to G of an air purification film composed of an overcoat film and an undercoat film. In Samples E to G, the weight ratio of the overcoat film to the base film was variously changed as shown in Table 2.

【0018】

[Table 2]

<img file="JPH10137329A_D0002.tif" />【0019】

Fig. 3 shows the membrane structure of the air purification membrane in which an overcoat membrane is formed on the surface of the base membrane. In FIG. 3, the structure of the air purification film is such that the base film 2 is formed on the surface of the base material 1, and the overcoat film 3 is further formed on the surface of the base film 2. Further, the overcoat film 3 and the undercoat film 2 contain an adsorbent 4, a photocatalyst 5, and a binder 6, respectively, and the photocatalyst 5 contained in the overcoat film 3 is larger than the photocatalyst 5 contained in the undercoat film 2. Many are included.

【0020】

1 (m) of the above samples E to G³ ), After purging the dry clean air, burn 5 mild sevens at the same time, and the air volume is 0.94 (m).³Ultraviolet rays 3.4 (mW / cm) for each sample while purifying the air with / min)² ), Acetaldehyde (Fig. 4), NOx (Fig. 5), carbon monoxide (Fig. 6), styrene (Fig. 7), acetic acid (Fig. 8), ammonia (Fig. 9) and pyridine (Fig. 9). The deodorizing performance (decomposition performance) in Fig. 10) was measured.

【0021】

As shown in FIG. 4, the residual rate of acetaldehyde decreased with time in Samples E and F, but in Sample G, the residual rate of acetaldehyde became a constant value with the passage of time. As shown in Fig. 5, the residual ratio of nitric oxide, which is typical of NOx, was good in samples E and F, but in sample G, 30% or more of nitric oxide remained even at 100 minutes. ..

【0022】

As shown in FIG. 6, the residual ratio of carbon monoxide was not significantly different between the samples E, F, and G. As shown in FIG. 7, the residual rate of styrene decreased with time in Samples E and F, but the residual rate of styrene in Sample G became a constant value with the passage of time. As shown in FIGS. 8, 9, and 10, the residual rates of acetic acid, ammonia, and pyridine were not significantly different among the samples E, F, and G, respectively.

【0023】

Based on the above results, various odors can be adsorbed and decomposed when the loading ratio (weight ratio) of the samples E and F, that is, the overcoat film and the base film is 1: 2 to 1: 4. ..

【0024】

As shown in FIG. 11, the adsorbent was selected from Cu-ZSM5, which is a high silica synthetic zeolite H-type ZSM5 subjected to copper ion exchange treatment, as having high adsorption performance for acetaldehyde, which has low decomposition efficiency by a photocatalyst. There was.

【0025】

[Effect of the invention]

Since the air purification membrane of the present invention has the above-mentioned structure, according to claim 1, the decomposition performance by the photocatalyst at the surface of the upper membrane and the interface between the upper membrane and the lower membrane is enhanced, and the adsorbed components are decomposed and decomposed. The ability to regenerate the adsorbent is increased, and the adsorption performance can be maintained for a long time. Further, since the odorous component adsorbed on the lower film always passes through the upper film even if it is desorbed from the adsorbent, the odor can be efficiently decomposed by ultraviolet rays.

【0026】

According to claim 2, by manipulating the ratio of the photocatalyst to the adsorbent in the upper film, the adsorption performance of aldehyde components, which have low adsorption performance by the photocatalyst alone, can be enhanced in the lower film, and the air of aldehydes can be improved. Suppresses detachment from the purifying membrane. In addition, the photocatalyst contained in the upper membrane makes it possible to deodorize NOx, which was difficult to deodorize with the adsorbent alone.

【0027】

According to claim 3, the amount of adsorption on the lower membrane is increased by manipulating the weight ratio between the upper membrane and the lower membrane.

【0028】

According to claim 4, since the adsorption performance for aldehydes having low adsorption performance is improved only by the photocatalyst, the compounding ratio of the photocatalyst to the adsorbent can be increased, and the decomposition efficiency can be improved.

【0029】

According to claim 5, an air purification membrane capable of adsorbing and decomposing various odors can be produced.

[Simple explanation of drawings]

[Figure 1]

It is explanatory drawing which shows the acetaldehyde purification performance by the layer film which changed the ratio of a photocatalyst and an adsorbent for this invention.

[Figure 2]

It is explanatory drawing which shows the nitrogen oxide purification performance by one layer membrane of FIG.

[Fig. 3]

It is sectional drawing which shows the membrane structure of the embodiment of the air purification membrane of this invention.

[Fig. 4]

It is explanatory drawing which shows the acetaldehyde purification performance by embodiment of the air purification membrane of this invention.

[Fig. 5]

It is explanatory drawing which shows the nitric oxide purification performance by embodiment of the air purification membrane of this invention.

[Fig. 6]

It is explanatory drawing which shows the carbon monoxide purification performance by embodiment of the air purification membrane of this invention.

[Fig. 7]

It is explanatory drawing which shows the styrene purification performance by embodiment of the air purification membrane of this invention.

[Fig. 8]

It is explanatory drawing which shows the acetic acid purification performance by embodiment of the air purification membrane of this invention.

[Fig. 9]

It is explanatory drawing which shows the ammonia purification performance by embodiment of the air purification membrane of this invention.

[Fig. 10]

It is explanatory drawing which shows the pyridine purification performance by embodiment of the air purification membrane of this invention.

[Fig. 11]

It is explanatory drawing which shows the acetaldehyde adsorption performance comparison in the dry state of the air purification membrane of this invention.

[Fig. 12]

It is a block diagram which shows the deodorizing apparatus using a conventional photocatalyst.

[Explanation of symbols]

1 base material 2 Undercoat 3 Overcoat film 4 Adsorbent 5 Photocatalyst 6 binder