JP2003236391A - Photocatalytic paper material and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photocatalytic paper material excellent in photocatalytic effect and durability, and to provide a method for producing the same. <P>SOLUTION: The photocatalytic paper material is produced by previously carrying a photocatalyst optionally mixed with an adsorbent on inorganic fibers and feeding the fibers to a paper making process and exhibits effects of decomposing and removing harmful substances such as sick house syndrome inducing substances and effects of improving the living environment such as antibacterial, mildew-proof and anti-tick properties by the photocatalyst without deteriorating the base fibers. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst paper-like material obtained by mixing inorganic fiber supporting a photocatalyst or an adsorbent or both with a base fiber and a method for producing the same, and more specifically to an organic fiber as the base fiber. A photocatalyst paper material that does not cause deterioration of the base material due to photocatalyst even when used, and exhibits the effect of decomposing and removing harmful substances such as sick house syndrome-inducing substances and the effect of improving the living environment such as antibacterial property, antifungal property and anti-mite property. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, various environmental pollution problems such as air pollution, water environment pollution and soil pollution have become serious. Among them, living environment pollution caused by chemical substance hypersensitivity-inducing substances that cause sick house syndrome and the like have a great influence on our daily lives. Therefore, it is indispensable to strengthen the regulations on the use of the above-mentioned causative substances and to take measures to purify the indoor environment which is already contaminated with various kinds of harmful substances.

As one of the measures for improvement thereof, there is adsorption removal using a porous material such as activated carbon, which is used for removing harmful substances by supporting it in a column shape or a filter. However, in this method, the adsorption ability gradually decreases with the adsorption of the harmful substance, and the removal effect disappears after the saturated adsorption. Therefore, it is necessary to frequently replace it in practical use.

Therefore, recently, a photocatalyst which exhibits a high redox power by irradiation with ultraviolet rays or visible rays has been attracting attention. In particular, titanium oxide is widely used because of its high photocatalytic activity, safety, and stability. Further, in addition to the ability to decompose and remove harmful substances and the deodorizing effect, it is also effective against biological factors such as antibacterial properties, antifungal properties, and anti-mite properties that deteriorate the living environment. However, since titanium oxide is a fine powder, some kind of immobilization is necessary for practical use, but since the photocatalytic reaction occurs on the surface of the titanium oxide particles, the immobilization method for coating the surface significantly lowers the photocatalytic activity. Further, when the carrier is an organic substance, there is a big drawback that the base fiber itself is decomposed and deteriorated by a photocatalytic reaction.

Therefore, inorganic resins, metals, ceramics, etc. are used as the photocatalyst-supporting substrate.
Paper and paper-like materials made of pulp fibers and synthetic organic fibers are
Due to the above drawbacks, it is difficult to use. However, paper and paper products are very familiar household items, and they are light and have good processability, and if photocatalytic activity can be given to them, the complex polluted environment in the living enclosed space will be greatly improved.

Recently, in order to utilize organic fibers as a substrate, compounding with a photocatalytically inactive substance such as an inorganic binder or hydroxyapatite has been studied. However, the coating of the photocatalytic functional surface or the immobilization layer is used. There are problems such as desorption of the photocatalyst, and it has not been put to practical use. Further, these methods have a problem that the manufacturing cost is high because the photocatalyst is supported by post-treatment such as coating after the paper is manufactured. Usually, paper and paper-like materials are produced by forming wet paper by dehydration of fiber suspension, squeezing and drying,
There is also a demand for a method of manufacturing a photocatalytic paper-like material by directly using this manufacturing process.

[0007]

As described above,
In order to use the photocatalyst as a daily life item,
Supporting organic fibers such as paper and paper products is effective, and there is a need for a molding method that does not cover the photocatalytic function surface, prevention of deterioration of organic base fibers, and development of a supporting method that can use the existing paper manufacturing process. Has been done.

In order to solve the above-mentioned conventional problems, the present invention provides a photocatalyst alone or in admixture with an adsorbent, which is preliminarily supported on an inorganic fiber, and then provided to a furnish as in the conventional papermaking additive. So, without deteriorating the organic fiber that is the base material, the effect of decomposing and removing harmful substances by photocatalyst and antibacterial property,
It is an object of the present invention to provide a photocatalyst paper-like product characterized by exhibiting a living environment improving effect such as antifungal property and anti-mite property, and a method for producing the same.

[0009]

Therefore, the photocatalyst paper-like material of the present invention is prepared by adding a cationic flocculant such as polydiallyldimethylammonium chloride to an inorganic fiber such as a ceramic fiber, and then adding a photocatalyst, and further adding an anionic property. The method is characterized in that after the photocatalyst is supported on the inorganic fibers by adding an anionic flocculant such as polyacrylamide, the base fibers such as wood pulp are added and the photocatalyst is manufactured by a wet method.

This makes it possible to suppress the deterioration of the base fiber by minimizing the contact between the photocatalyst and the base fiber, and to exert the effect of decomposing and removing harmful substances and improving the living environment by the photocatalyst. Become.

The photocatalyst paper-like material of the present invention is characterized in that the effect of decomposing and removing harmful substances is improved by supporting an adsorbent on inorganic fibers or base fibers.

As a result, it is possible to improve the effect of decomposing and removing harmful substances by the photocatalyst due to the effect of trapping harmful substances and the effect of concentrating harmful substances by the adsorbent.

Further, the photocatalyst paper-like material of the present invention is obtained by internally adding one or more ionic coagulants to the inorganic fiber suspension so that the photocatalyst or the adsorbent added to the suspension or both of them. Is carried on an inorganic fiber, and then mixed with a base fiber to make a paper.

This makes it possible to manufacture the photocatalytic paper-like material by using the existing paper manufacturing process as it is.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The constituent elements of the photocatalyst paper-like material of the present invention and the method for producing the same are described in detail below.

Examples of the photocatalyst used in the present invention include titanium oxide, zinc oxide, cerium oxide, metal oxide photocatalysts, inorganic photocatalysts, organic photocatalysts, and composites thereof, and the like, in view of stability, safety and photocatalytic activity. The excellent titanium oxide is advantageously used.

Examples of the adsorbent used in the present invention include zeolite, silica, alumina, sepiolite, halosite, activated carbon, activated clay, metal oxides, porous inorganic substances or porous organic substances, and composites thereof. Zeolite can be advantageously used as an adsorbent because its pore size can be adjusted to maximize the adsorption efficiency according to various harmful substances.

Examples of the inorganic fibers used in the present invention include ceramic fibers, glass fibers, slag fibers, asbestos, etc., and ceramic fibers excellent in stability, safety and strength are advantageously used.

Examples of the base fiber used in the present invention include fibrous substances such as wood pulp, linter pulp, synthetic pulp, synthetic organic fiber, and natural pulp which is inexpensive and has a wide range of applications is advantageously used.

For the production of the photocatalyst paper-like material, a handmade machine such as Japanese paper, a cylinder paper machine, a Fourdrinier paper machine, a twin wire paper machine and the like can be used. Without special post-treatment such as coating treatment in conventional photocatalytic paper manufacturing,
The photocatalytic paper-like material can be obtained only by heating and drying the wet paper after dehydration.

[0021]

The photocatalyst paper-like material of the present invention will be specifically described below with reference to the effects of decomposing and removing formaldehyde, which is a typical sick house causative substance, and tensile strength, which is a typical paper strength characteristic. However, the present invention is not limited to these examples. In addition, "part" and "%" in the following examples show the ratio on a weight basis.

[Example 1] 0.12% of ceramic fiber
To 10 parts of an aqueous suspension, 1 part of a 0.012% aqueous solution of polydiallyldimethylammonium chloride was added to obtain 600r.
Stir at pm, and after 3 minutes, titanium oxide (made by Ishihara Sangyo Co., Ltd., S
10 parts of 0.15% water suspension of T-01) was added, and 3
After a minute, an anionic flocculant (HH-35 manufactured by Kurita Water Industries Ltd.)
1 part of 0.012% aqueous solution of 1) was added, and after 3 minutes, 80 parts of 0.15% water suspension of wood pulp beaten to 450 ml of Canadian Standard Freeness was added,
After 5 minutes, a sheet was prepared according to JIS P 8209. This is 3.5kP using a handmade paper press
a, it was pressed for 5 minutes, dried at 105 ° C. for 10 minutes by blowing air, and the obtained photocatalyst paper sheet having a basis weight of 60 g / m ² was used as Example 1.

[Example 2] In Example 1, a 0.15% aqueous suspension of titanium oxide was added to 7 parts, and the zeolite (Y
Type, manufactured by Tosoh Corporation, HSZ-320NAA) 0.15%
Except that 3 parts of the water suspension was added, the same treatment as in Example 1 was carried out, and the result was Example 2.

[Example 3] In Example 1, 5 parts of a 0.15% aqueous suspension of titanium oxide was added to prepare a 0.10% suspension of titanium oxide.
Example 1 except that 5 parts of a 15% water suspension was added.
Example 3 was carried out by performing exactly the same treatment as described above.

[Example 4] In Example 1, 3 parts of a 0.15% aqueous suspension of titanium oxide was added, and zeolite of 0.15% was added.
Example 1 except that 7 parts of a 15% water suspension was added.
The same treatment as the above was carried out to obtain Example 4.

Example 5 In Example 1, 0.1 part of a 0.15% aqueous suspension of titanium oxide was added to 0 part, and zeolite of 0.
Except that 10 parts of a 15% aqueous suspension was added, the same treatment as in Example 1 was carried out in all to give Example 5.

Comparative Example 1 Comparative Example 1 was carried out in the same manner as in Example 1, except that the 0.12% aqueous suspension of the ceramic fiber was changed to 0 part.

Comparative Example 2 Comparative Example 2 was carried out in the same manner as in Example 2 except that the 0.12% aqueous suspension of the ceramic fiber was changed to 0 part.

[Comparative Example 3] Comparative Example 3 was carried out in the same manner as in Example 3, except that the 0.12% aqueous suspension of the ceramic fiber was changed to 0 part.

Comparative Example 4 Comparative Example 4 was carried out in the same manner as in Example 4 except that the 0.12% aqueous suspension of the ceramic fiber was changed to 0 part.

[Comparative Example 5] Comparative Example 5 was carried out in the same manner as in Example 5 except that the 0.12% aqueous suspension of the ceramic fiber was changed to 0 part.

Comparative Example 6 In Example 1, 0.12% aqueous suspension of ceramic fibers was made into 0 part, 0.012% aqueous solution of polydiallyldimethylammonium chloride was made into 0 part, and titanium dioxide was added at 0. Comparative Example 6 was carried out in the same manner as in Example 1 except that 30 parts of a 15% aqueous suspension and 0 part of a 0.012% aqueous solution of an anionic flocculant were used.

COMPARATIVE EXAMPLE 7 In Example 1, 0.12% aqueous suspension of ceramic fiber was used as 0 part, 0.012% aqueous solution of polydiallyldimethylammonium chloride was used as 0 part, and titanium oxide of 0.12% was added. Comparative Example 7 was carried out in the same manner as in Example 1 except that the amount of the 15% aqueous suspension was changed to 0 part and the anionic flocculant 0.012% aqueous solution was changed to 0 part.

As described above, the photocatalyst paper-like material obtained in the example and the paper-like material of the comparative example were subjected to a formaldehyde adsorption decomposition test and a paper strength test.

[Formaldehyde Adsorption Decomposition Test] After placing the paper-like materials of Examples and Comparative Examples of 25 mm × 25 mm in a stainless steel reaction container having a quartz cover and a volume of 200 cc, the reaction container has a content of 25 ppm. Formaldehyde was injected with a microsyringe.
Under UV irradiation (wavelength 365 nm, 0.3 mW / cm ² ).
In, the formaldehyde concentration in the reaction vessel was measured every predetermined time. A gas chromatograph was used to quantify formaldehyde.

[Paper Strength Test] The paper strength test is JIS
Dry tensile strength is measured according to P 8113, and initial tensile strength and ultraviolet irradiation (wavelength 365 nm, 2.1 mW /
cm ² ) was carried out for 240 hours, and then the tensile strength was measured.
The results are shown in (Table).

[0037]

【table】

According to the table, as in Examples 1 to 5 and Comparative Examples 1 to 5, the formaldehyde decomposition and removal efficiency shows the same tendency regardless of the presence or absence of the inorganic fiber, but titanium oxide was supported by the aggregating agent. In Example 1 and Comparative Example 1, as compared with Comparative Example 6 in which titanium oxide was forcibly retained by a physical filtration effect without using a coagulant, even if the amount of titanium oxide was the same, the initial decomposition of formaldehyde was performed. The amount is slightly small, and the apparent specific surface area is reduced due to the aggregation of the inorganic powder, and the photocatalytic performance is slightly reduced. However, Examples 2-5 and Comparative Example 2-
By complexing with zeolite, which is an adsorbent, as in 5, the formaldehyde is adsorbed and removed, and the initial removal efficiency is improved. However, as the titanium oxide content decreases and the zeolite content increases, formaldehyde is detected even after 60 minutes of UV irradiation as in Examples 3 to 5 and Comparative Examples 3 to 5, and the photocatalytic effect is insufficient. Therefore, the final decomposition and removal ability of formaldehyde is lowered. In addition, the paper-like material of Comparative Example 7 prepared from only pulp fibers does not have the effect of decomposing and removing formaldehyde.

Regarding paper strength, Examples 1 to 5 in which titanium oxide and zeolite are supported on inorganic fibers exhibit paper strength substantially the same as that of the paper of Comparative Example 7 prepared from only pulp fibers. However, in Comparative Examples 1 to 5 in which the pulp fiber is directly supported on the pulp fiber and Comparative Example 6 in which titanium oxide is forcibly retained by the physical filtration effect without using the flocculant, the paper strength is Markedly reduced. In Comparative Examples 1 to 6, the inorganic component directly supported on the pulp fibers inhibits the bonding between the pulp fibers, whereas in Examples 1 to 5, the inorganic components are supported on the inorganic fibers to cause the inter-pulp fiber bonding. Most of the bonds are retained. Also, regarding the paper strength after 240 hours of ultraviolet irradiation, in Comparative Examples 1 to 4, the decrease in paper strength becomes remarkable with an increase in the amount of titanium oxide, and in Comparative Example 6, the decrease in paper strength is remarkable. As can be seen, Examples 1 to 1
In No. 4, the initial paper strength is maintained. Examples 1 to 4
Then, since the amount of titanium oxide in contact with the pulp fiber is small, there is almost no deterioration of the base material due to ultraviolet irradiation, and in Comparative Examples 1 to 4 and Comparative Example 6, the titanium oxide is in direct contact with the pulp fiber. However, the deterioration of the base material due to the photocatalytic action is severe. In particular, in Comparative Example 6 in which no aggregating agent is used, the deterioration effect is extremely large and it cannot be put to practical use. In addition, in Example 5, which does not contain titanium oxide, Comparative Example 5 and Comparative Example 7, there was no effect of ultraviolet irradiation on the paper strength.

As described above, in the photocatalyst paper-like material of the present invention, the weight ratio of titanium oxide and zeolite in the sheet is 7: 3 based on the total weight of titanium oxide and zeolite. 2 is the most effective. In addition,
When the amount of titanium oxide is used as a reference, the initial adsorption amount increases as the amount of zeolite increases, and the removal efficiency improves.

[0040]

As described above, according to the first aspect of the present invention.
The photocatalyst paper-like material described in 1. is a photocatalyst paper-like material in which the inorganic fiber supporting the photocatalyst is mixed with the base material fiber, and therefore the deterioration of the base material is caused by minimizing the contact between the photocatalyst and the base material fiber. The effect of decomposing and removing harmful substances by the photocatalyst and improving the living environment can be exhibited.

In the photocatalyst paper-like material according to the second aspect, by using an adsorbent in combination, a harmful substance capturing effect and a harmful substance concentrating effect are imparted, and the photocatalyst decomposing and removing effect of the harmful substances can be improved.

In the method for producing a photocatalyst paper-like material according to a third aspect of the present invention, the photocatalyst added to the suspension by internally adding one or more ionic flocculants to the inorganic fiber suspension. Alternatively, by adsorbing an adsorbent or both on an inorganic fiber and then mixing with a base fiber, the deterioration of the base material is suppressed by minimizing the contact between the photocatalyst and the base fiber, and the harmful substance is decomposed by the photocatalyst. It is possible to produce a photocatalyst paper-like material that can exhibit a removing effect and a living environment improving effect.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) B01J 21/06 B01D 53/36 J 35/06 ZABG (72) Inventor Hiroo Tanaka Nishishin, Sawara-ku, Fukuoka-shi, Fukuoka 2-chome No. 21-33 F term (reference) 4C080 AA05 AA07 BB02 BB05 BB08 HH05 JJ03 JJ06 KK08 LL02 LL03 LL10 MM02 MM03 MM04 MM05 MM06 MM11 NN01 NN02 NN22 NN22 NN24 4D048 AA19 AB03 BA08B08A08B04A01 BA03 BA07X BA11X BA48A CA01 CA10 CA11 DA06 EA10 FA01 FA03 FB04 FB15 FB68 FC03 ZA04B

Claims (3)

[Claims] 1. A photocatalyst paper material in which inorganic fibers supporting a photocatalyst are mixed with a base fiber to suppress the deterioration of the base material by minimizing the contact between the photocatalyst and the base fiber, Further, a photocatalyst paper-like material characterized by exhibiting the effect of decomposing and removing harmful substances by a photocatalyst and improving the living environment. 2. The photocatalyst paper material according to claim 1, wherein the effect of decomposing and removing harmful substances is improved by using an adsorbent together. 3. A photocatalyst or an adsorbent or both added to the suspension is supported on the inorganic fiber by internally adding one or more ionic coagulants to the inorganic fiber suspension.
The method for producing a photocatalyst paper-like material according to claim 1 or 2, wherein the paper is mixed with the base fiber after that.