JPH10237794A - Paper and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a functional substance to the surface of paper in excellent processability and durability without losing the activity of the functional material and without deteriorating paper, by forming a silica film containing powder of the functional substance on the surface of paper. SOLUTION: Powder having function such as photocatalyst, deodorizing and antimicrobial properties is uniformly fixed to a silica film. The powder is fixed through the silica film to the surface of the paper. A silica film containing a functional substance can be formed on the surface of paper by a method for coating the surface of paper with a coating material obtained by dispersing powder of a functional substance into silicic acid ester, water and/or an organic solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to paper useful for decomposing, removing and sterilizing various odorous gases and harmful gases generated in daily life, harmful compounds in water, etc. And a paper having on its surface a silica film containing a photocatalytically active substance such as titanium dioxide, zinc oxide, iron oxide or the like, which exhibits an effect of decomposing inorganic substances, and a deodorant. The silica film on the surface of the obtained paper is
It has the feature of being excellent in workability and weather resistance.

[0002]

2. Description of the Related Art It is widely known that when a photocatalyst such as titanium dioxide is irradiated with ultraviolet rays, electrons are transferred from a valence band to a conduction band by photoexcitation to form an n-type semiconductor, which exhibits the decomposition and sterilization effects of various compounds. Decomposition of underwater organic matter ("Water and wastewater" vol.30 No.10 (1988)
p943-948), decomposition of organic matter, deodorization, sterilization ("Surface" vol. 25 No. 8 (1987) p477-49)
5, "Ceramics" 21 (1986) No. 4, p3
26-333).
However, if the photocatalytic activity is actually used for the purpose of decomposing and removing and sterilizing harmful gases in exhaust gas, odorous gases such as tobacco and toilets, harmful substances such as pesticides, environmental pollutants, etc. Supported on some substrate,
It is necessary to fix. In addition, powders of various functional substances, such as deodorants, which have been recently developed, are rarely used in the form of powder.

Conventionally, when a powder of a functional substance such as titanium dioxide is used for paper, the powder is carried inside the paper, and a paint having the powder of the functional substance is applied to the surface of the paper to apply it to the surface of the paper. No functional substance powder was present in the powder. This is because when the functional substance powder and the resin are mixed and applied to the surface of paper, the surface of the functional substance powder is covered with the resin, and the effect cannot be exhibited. As a method of adding titanium dioxide for photocatalyst to paper, a method of forming titanium dioxide particles into an aggregate, a method of supporting titanium dioxide particles on inorganic particles such as activated carbon, and a method of coating titanium dioxide particles with an inorganic material such as silica or alumina A method was proposed. These methods attempt to improve the decomposition of paper fibers by reducing the contact points between the titanium dioxide particles and the paper.However, the decomposition proceeds at the contact points between the paper and the titanium dioxide particles, and the formation by the contact reaction occurs. Object, such as NOx
It does not prevent the degradation due to nitric acid resulting from the reaction. In addition, there is a problem that the activity of the titanium dioxide particles is greatly reduced by the coating, and a great deal of labor is required for performing these treatments and processing.

The above problems are common to all highly active substances such as photocatalysts other than titanium dioxide, and furthermore, adsorbents and bactericides. When these highly active substances are put into practical use, their activity is not reduced. A fixing method that is excellent in strength, inexpensive, and easy to handle has been desired. The present inventors, a substrate, a resin layer formed on the substrate surface, a silica film fixed on the resin layer, and an article having a silica film containing a functional substance powder fixed on the silica film, JP 9
-613. This article is excellent in deodorizing performance, photocatalytic performance, processability and weather resistance, but when the substrate is a metal material, glass, ceramics, etc.
To fix the substrate and the silica film, it was necessary to provide a resin layer on the substrate.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a deodorizing effect of a deodorizing agent, a bactericidal effect of an antibacterial agent, a photocatalytic activity of titanium dioxide, etc. , NO _X , S
O _X, maintaining hydrocarbon, harmful gases formalin harmful substances pesticides, decomposition removal and sterilization of environmental pollutants, fungicidal, algicidal effect, etc., the activity capacity of the functional material itself,
Another object of the present invention is to provide a paper having a functional film excellent in processability, durability, and weather resistance, and a paper product using the paper, for example, an antibacterial agent and a deodorant.

The inventors of the present invention have conducted intensive studies on a simpler method for immobilizing a functional substance on a substrate. As a result, surprisingly, when the substrate is paper, a resin layer is required. By providing a silica film containing functional substance powder directly on the surface of the paper, unlike the case of using other resins, the characteristics of the functional substance are not lost, the deodorizing effect of the deodorant, Odorous gases such as aldehydes and mercaptans, NO
Demonstrates photocatalytic effects such as decomposition and removal of harmful gases such as x, harmful substances such as pesticides, environmental pollutants, and the like, and the applied paint has good adhesion, processability, and weather resistance without heating. The inventors have found that the present invention is excellent, and completed the present invention.

That is, the present invention relates to a paper having on its surface a silica film containing a functional substance powder. Any paper may be used as long as the paper, which is the substrate, is permeable to water and / or an organic solvent containing silica sol on the surface thereof and can form a silica film by drying. For example, securities paper, book paper, newsprint,
Printing paper such as imitation paper, book paper, writing paper such as stationery paper, Kent paper, drawing paper such as watercolor paper, wrapping paper such as wrapping paper, sack paper, absorbent paper such as blotter paper, filter paper, copy paper, towel paper, etc. , Mount, pattern, box, architectural paperboard, art paper,
Examples include Western paper and various types of Japanese paper, such as photographic paper, carbon paper, and paraffin paper, and these can be used alone or in combination depending on the purpose of use.

The functional substance powder used in the present invention refers to a powder having functions such as photocatalyst, deodorization and antibacterial. Titanium dioxide and iron oxide having a photocatalyst function, and powder having a deodorization function. Titanium dioxide, iron oxide, zinc oxide, and compounds having an antibacterial function include compounds such as silver, copper, and zinc. Further, a porous body carrying these, a microcapsule containing a drug, and the like are also included. Although these have high activity, the surface is easily covered during fixation or loses their function easily by heating, and when fixed by coating with a resin or the like, the resin is deteriorated and peels off. There are many problems.

The fixation with the silica film of the present invention deteriorates the paper by fixing these highly active substances uniformly in the silica film at a relatively low temperature and further fixing the highly active substance on the paper surface via the silica film. Without fear, the silica layer is used as a strong binder to enable fixing to paper. When the substrate is paper, the reason why the silica film is firmly fixed without the resin layer is not clear, but in the production of the paper of the present invention, the silica sol containing the functional substance powder is sufficiently contained in the paper fibers. The inventors presume that the silica film and the paper formed after drying may be integrated at the interface because of the permeation of the silica film.

The particle size of the functional substance powder is preferably 5 μm or less for the strength of the coating film, more preferably 0.5 μm.
m or less, and most preferably 0.1 μm or less.
As an example of the functional substance powder, titanium dioxide for a photocatalyst is preferably an anatase type, and the specific surface area is preferably 20 m ² / g or more, more preferably 50 m ² / g or more. Also, titanium dioxide includes W, Sn, Mo, V, Mn and Zn.
It is also preferable to include a metal oxide for improving the catalytic activity such as the above. In addition to the functional substance powder, a pigment or the like can be added to the silica film.

In the paper of the present invention, when titanium dioxide for a photocatalyst is used as the functional substance powder, the surface layer absorbs ultraviolet energy as compared with paper in which general titanium dioxide is internally added as a white pigment. Is formed, so that the light resistance of the paper is improved. The paper of the invention can be processed into any shape. For example, if it is fixed to a metal material, glass, ceramic, resin, building material, or the like by sticking or crimping, it can be applied to not only general household wallpaper but also anything that can be used indoors. In the prepared silica film containing the functional substance powder, excess silica is absorbed by the paper, and the functional substance powder is exposed on the film surface to easily obtain high activity. May be exfoliated.
In this case, in addition to adjusting the compounding ratio of the coating material, a method in which a silica sol containing no functional substance powder is applied in advance and the coating material of the present invention is applied thereon is also possible. By adjusting the mixing ratio of the undercoat and the paint, the coating thickness becomes 10
The thickness may be at least 00 μm, but is preferably 5 to 200 μm from the viewpoint of film strength, activity, handling and the like.

In this specification, the expression "film" is used, but this includes a film attached in the form of an island and particles, and does not necessarily mean that the entire surface of the paper is covered. . The ratio of the functional substance powder in the silica film containing the functional substance powder is 10 to 10 from the balance between the film strength and the activity.
It is preferably 90% by weight, more preferably 20-85% by weight, most preferably 40-80% by weight. In the silica film containing the functional substance powder of the present invention, after solidifying the film, the remaining acid is removed by immersing the film in water having a pH of 6 to 14, thereby improving the durability of the paper. preferable. At the same time, removing the organic solvent, the attached matter, etc. cleans the surface of the functional substance and improves the activity, which is preferable.

The present invention further provides a method for producing the above article, wherein the paper surface is coated with a coating material in which a functional substance powder is dispersed in a silicate ester, water and / or an organic solvent. Any known silicate ester can be used, but methyl silicate, ethyl silicate, and butyl silicate are preferred, and ethyl silicate is most preferred.

[0014] Typical examples of the solvent include alcohols such as cellosolves and carbitol. Among the cellosolves, those having an alkyl group are preferable, and butyl cellosolve having a butyl group is particularly preferable. Among carbitols, carbitol and carbitol acetate are preferred. Among alcohols, ethanol and butanol are preferable. Water is added to the paint to hydrolyze the silicate ester, but in order to increase the dispersibility of the functional substance powder in the paint and the strength of the coating film, the paint pH is preferably acidic, and pH 4 or less is more preferable. A pH of 2 or less is particularly preferred. In order to lower the paint pH, a small amount of acid may be added, and any of hydrochloric acid, sulfuric acid, nitric acid and the like can be used. Further, the pH of the mixed liquid which is a raw material of the silica film not containing the functional substance powder is preferably acidic. The silica film in the present invention becomes porous due to dehydration and evaporation of alcohol from silica sol generated by hydrolysis of silicate ester, and evaporation of organic solvent, and the contained functional substance powder particles contain atmospheric gas, water, and bacteria. It is thought that they can easily react with these because they easily come into contact with surface adsorbed substances such as.

The proportion of the coating material for preparing the silica film containing the functional substance powder is such that when ethyl silicate is used as the silicate ester per 100 parts by weight of the functional substance powder, To 3200 parts by weight, preferably 60 to 1400 parts by weight, more preferably 80 to 5 parts by weight.
20 parts by weight, and when methyl silicate and butyl silicate are used as the silicate ester, the preferable amount is a coefficient corresponding to the ratio of the respective molecular weights, and 0.73 and 1.54 are converted into numerical values in ethyl silicate. Multiplied value. Solvent 0-1
000 parts by weight, preferably 0 to 500 parts by weight, and water is 10 to 1100 parts by weight, preferably 20 to 500 parts by weight. When the amount of the functional substance powder is less than the above-mentioned mixing ratio, the activity as a film is lowered. When the amount is more than the above-mentioned mixing ratio, the adhesion and strength of the silica film are not preferable.

The paper according to the present invention is suitably used as a deodorant or an antibacterial agent. That is, the present invention provides, as one embodiment, a paper and a deodorant and an antibacterial agent containing a functional substance powder and having a silica film fixed on the paper. Among the functional substances, titanium dioxide and the like having photocatalytic activity include aldehydes, mercaptans and other deodorizing effects, as well as NOx, ammonia, inorganic gases such as hydrogen sulfide, harmful substances such as agricultural chemicals, and environmental pollutants. Decomposition and removal and sterilization and removal of fungi and algae are known as photocatalytic effects, and when a deodorizing effect is obtained, it is clear that other effects known as photocatalytic effects can be obtained at the same time. Examples are given below,
Although the contents of the present invention will be described in more detail, these examples are merely examples, and the scope of the present invention is not limited thereto.

Example 1 9 g of ethyl silicate, 3 g of water to which 0.5 mol of hydrochloric acid was added, and 6 g of butyl cellosolve were mixed.
No. 3022, 6 g of a deodorant (specific surface area: 220 m ² / g, average particle size: 0.4 μm) composed of tightly bound particles of titanium dioxide and zinc oxide prepared according to the procedure of Example 5, and 60 g of 3 mm glass beads The mixture was charged into a 120 ml mayonnaise bottle, dispersed and mixed with a paint conditioner manufactured by Red Devil Co. for 10 minutes to obtain a paint containing a deodorant and silica sol. The above paint was applied to the paper with a 2 mil doctor blade. After drying at 120 ° C. for 1 hour, the substrate was washed with pure water at 90 ° C. to remove residual chlorine ions, butyl cellosolve, and the like. From observation with a scanning electron microscope, it is considered that a layer of deodorant particles is formed on the paper surface to a thickness of about 10 μm, and the particles are fixed by silica. This film did not peel off even when washed with pure water and hot water at 90 ° C., and there was no powder adhesion even when the coated surface was rubbed by hand. Cut the coating surface 5cm x 1cm, put it in a 120ml glass bottle, and acetaldehyde gas concentration of 100p in the bottle
pm, and the mixture was allowed to stand at room temperature for 1 hour. The air in the bottle was measured with a gas chromatograph G3800 (detector FID) manufactured by Yanagimoto Seisakusho. The acetaldehyde concentration was 0 ppm. When the same experiment was performed for other gases, the following results were obtained. Acetic acid 50ppm
Was 0 ppm after 1 hour. Trimethylamine 10
0 ppm was 0 ppm after 1 hour. 100 ppm of ethyl mercaptan was 0 ppm after 1 hour. Dimethyl sulfide 50 ppm was 0 ppm after 1 hour.

Example 2 Titanium dioxide (anatase type, specific surface area: 120 m ² /
g, average particle size 0.1 μm), 6 g of ethyl silicate, 3 g of water to which 0.5 mol of hydrochloric acid was added, and 6 g of butyl cellosolve together with 90 g of 3 mm glass beads in 120 ml.
In a mayonnaise bottle, and dispersed and mixed for 10 minutes with a paint conditioner manufactured by Red Devil Co., Ltd. to obtain a paint containing titanium dioxide and silica sol. The above paint was applied to the paper with a 2 mil doctor blade. After drying at 120 ° C. for 1 hour, it was immersed in a caustic soda solution of pH 10 for 5 seconds and washed with pure water at 90 ° C. It was dried again at 170 ° C. for 1 hour. According to the scanning electron microscope observation, a layer of deodorant particles was formed to a thickness of about 10 μm on the paper surface. This film did not peel off even when washed with hot water at 90 ° C., and no powder adhered even when the coated surface was rubbed with a hand. The coating film cut into 5 cm × 1 cm is put into a 120 ml glass bottle, acetaldehyde is injected in an amount such that the gas concentration in the bottle becomes 1000 ppm, and ultraviolet light having a wavelength of 350 nm is applied from outside the bottle to 4.0-4.4.
After irradiating for 1 hour at mW / cm ² , the air in the bottle was gas chromatographed by Yanagimoto Seisakusho G3800 (detector FID).
As a result, the concentration of acetaldehyde was 0 ppm. When the same experiment was performed for other gases, the following results were obtained. Acetic acid 50 ppm became 0 ppm by ultraviolet irradiation for 1 hour. Trimethylamine 1
00 ppm was reduced to 0 ppm by irradiation for one hour with ultraviolet light. Ethyl mercaptan 100 ppm became 60 ppm by ultraviolet irradiation for 1 hour. Dimethyl sulfide 50
The ppm became 0 ppm by one-hour ultraviolet irradiation.

Further, a slurry obtained by dispersing 10 mg (approximately the same amount as contained in a 5 cm × 1 cm surface) of the titanium dioxide powder for a catalyst used in Example 1 in pure water was used to obtain a 5 cm × 1 cm slurry.
When the acetaldehyde decomposition test was performed in the same manner on the aluminum plate coated and dried, the reduction rate of the concentration was almost the same. Further, the coating film was irradiated with ultraviolet rays for 50 hours using a Dew panel light control weather meter manufactured by Suga Test Instruments Co., Ltd., but no discoloration of the coating film and paper and no peeling of the coating film occurred.

Example 3 In Example 2, the paint was iron oxide (acicular hematite,
Specific surface area 40 m ² / g, major axis / minor axis ratio 5) 6 g, 9 g of ethyl silicate, 3 g of water to which 0.5 mol of nitric acid was added, and 6 g of butyl cellosolve were charged into a 120 ml mayonnaise bottle together with 90 g of 3 mm glass beads. A silica film containing iron oxide was prepared on a substrate in the same manner except that the silica film was prepared by dispersing and mixing with a paint conditioner manufactured by the company for 10 minutes.

Comparative Example 1 A coating obtained by mixing titanium dioxide, ethyl silicate, water containing 0.5 mol of hydrochloric acid and butyl cellosolve in Example 1 was applied to an aluminum plate with a 2 mil doctor blade. After drying at 120 ° C. for 1 hour, a layer of titanium dioxide particles was formed to a thickness of about 20 μm on the aluminum plate surface by scanning electron microscope observation. pH1
When immersed in a caustic soda solution of 0, the titanium dioxide peeled off.

Comparative Example 2 A film was prepared by kneading 20 wt% of a deodorant consisting of a mixture of titanium dioxide and zinc oxide into a vinyl chloride resin, and using a Suga Test Instruments Co., Ltd. Dew Panel Light Control Weather Meter. When the film was irradiated with ultraviolet rays for 50 hours, the film turned brown.

Comparative Example 3 A paper in which titanium dioxide was dispersed in an acrylic resin by 80 wt% was applied to paper. A coating film cut into 5 cm × 1 cm is put into a 120 ml glass bottle, acetaldehyde is injected in an amount such that the gas concentration in the bottle becomes 1000 ppm, and ultraviolet light having a wavelength of 350 nm is applied from outside the bottle to 4.0-4.4 mW / c.
After irradiation for 1 hour at m ² , the air in the bottle was measured with a gas chromatograph G3800 (detector FID) manufactured by Yanagimoto Seisakusho, and the acetaldehyde concentration was unchanged at 1000 ppm. When the same experiment was performed for other gases, the following results were obtained. Acetic acid 50 ppm is 1
It became 40 ppm by ultraviolet irradiation for a long time. 100 ppm of trimethylamine is 85 ppm by UV irradiation for 1 hour
It became. Ethyl mercaptan 100 ppm was not changed to 100 ppm by ultraviolet irradiation for 1 hour. Dimethyl sulfide 50 ppm is 50
ppm. The acrylic resin film was peeled off by UV irradiation for 50 hours using a Dew Panel Light Control Weather Meter manufactured by Suga Test Instruments Co., Ltd.

COMPARATIVE EXAMPLE 4 A paper in which 80% by weight of titanium dioxide was dispersed in a urethane resin was applied to paper. A coating film cut into 5 cm × 1 cm is put into a 120 ml glass bottle, acetaldehyde is injected in an amount such that the gas concentration in the bottle becomes 1000 ppm, and ultraviolet light having a wavelength of 350 nm is applied from outside the bottle to 4.0-4.4 mW / c.
After irradiation for 1 hour at m ² , the air in the bottle was measured with a gas chromatograph G3800 (detector FID) manufactured by Yanagimoto Seisakusho, and the acetaldehyde concentration was unchanged at 1000 ppm. When the same experiment was performed for other gases, the following results were obtained. Acetic acid 50 ppm is 1
It became 45 ppm by ultraviolet irradiation for a long time. Trimethylamine 100ppm is 90ppm by UV irradiation for 1 hour
It became. Ethyl mercaptan 100 ppm was not changed to 100 ppm by ultraviolet irradiation for 1 hour. Dimethyl sulfide 50 ppm is 50
ppm. The urethane resin film was peeled off by ultraviolet irradiation for 50 hours using a Dew Panel light control weather meter manufactured by Suga Test Instruments Co., Ltd.

Comparative Example 5 100 g of the titanium dioxide particles of Example 2 was added to 500 ml of pure water.
The slurry was applied to paper with a 2 mil doctor blade and dried at 120 ° C. for 1 hour. This is pH
When immersed in a caustic soda solution of No. 10, the titanium dioxide particles peeled off.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Tatsuo Saito 25 Titan Kogyo Co., Ltd. at 1978 Kogushi, Ube City, Yamaguchi Prefecture

Claims (6)

[Claims] 1. A paper having on its surface a silica film containing a functional substance powder. 2. The paper according to claim 1, wherein the functional substance powder is selected from titanium dioxide, zinc oxide and iron oxide, or a combination thereof. 3. The method for producing paper according to claim 1, comprising applying a coating material in which a functional substance powder is dispersed in a silicate ester and water and / or an organic solvent to the paper surface. 4. The coating material contains 20 to 5000 parts by weight of a silicate ester and 100 parts by weight of water based on 100 parts by weight of a functional substance powder.
The production method according to claim 3, wherein the coating is a coating mixed and dispersed at a ratio of 0 to 1100 parts by weight and 0 to 1000 parts by weight of an organic solvent. 5. A deodorant comprising the paper according to claim 1 or 2. 6. An antibacterial agent comprising the paper according to claim 1.