JP2000248199A - Titanium oxide paint composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous titanium oxide paint composition having excellent stock stability and photodecomposition property. SOLUTION: An aqueous titanium oxide paint composition comprises a titanium oxide fine particle and a binder. The binder comprises an inorganic binder selected from a silica sol and an alumina sol and a organic polymer binder. The blending ratio of the titanium oxide fine particle and the inorganic binder is 5:1-1:5 in weight. The blending ratio of the organic polymer binder is 3-25 wt.% against the whole solid content of the paint composition. The viscocity of the paint composition at 20 deg.C by a B type rotation viscometer is 200-1,500 cps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water-based titanium oxide coating composition, and more particularly to a water-based titanium oxide coating composition having excellent storage stability and photodegradability.

[0002]

2. Description of the Related Art With increasing interest in the living environment, there has been an increasing demand for the removal of harmful substances in daily life such as odors, and the development of air purifiers incorporating odor removal devices and the like has been actively carried out. I have. In these apparatuses, a filter mainly containing activated carbon is used, and a method of adsorbing malodorous substances on activated carbon has been adopted. However,
Activated carbon has an adsorbing effect but has no decomposition ability, so it becomes saturated when a certain amount of malodorous substance is absorbed, and the filter must be replaced periodically.

In recent years, as a solution to such a problem, a composite material in which activated carbon and a catalyst for decomposing harmful substances are combined has been developed. For example, JP-A-1-234729 describes an air conditioner incorporating a photoreactive semiconductor composite in which titanium oxide is supported on honeycomb activated carbon. In this case, a part of the malodor component to be adsorbed is decomposed by OH radicals generated in the photoreactive semiconductor, so that the adsorption ability of the activated carbon can be maintained for a relatively long time.
However, this method requires activated carbon having a special honeycomb structure in order to support the photoreactive semiconductor and enhance the photoreaction efficiency, and requires a special process for retaining titanium oxide on the surface and inside the honeycomb. Was needed.

[0004] Japanese Patent Application Laid-Open No. 2-252241 describes a photocatalytic device in which a hollow cylindrical honeycomb structure made of a metal oxide catalyst is provided around an ultraviolet irradiation lamp.

Further, a method for removing harmful substances in a gas phase using photocatalytic titanium oxide is disclosed. For example, JP-A-2-253848 describes an ozone decomposition catalyst in which an anatase type titanium oxide is supported on an inorganic fibrous carrier. In Japanese Patent Application Laid-Open No. 3-233100, a mixture of titanium dioxide and activated carbon and a mixture having a wavelength of 300 n
It describes a ventilating facility consisting of a light source that emits light of m or more. JP-A-4-256755 discloses that titanium dioxide can be used as a deodorant and deodorant for home use by supporting it on granular pulp. Further, Kusunaga et al. Carried out photodecomposition of organic halogen compounds by holding titanium dioxide on ceramic paper (Journal of the Electrochemical Society, vol. 60, p. 107, 1992).
Year).

[0006] The photocatalytic decomposition of gas-phase harmful substances by the photocatalytic titanium oxide includes the approach of the gas-phase harmful substances to the titanium oxide photocatalyst, adsorption, photodecomposition by near-ultraviolet light, and elimination of by-products generated on the titanium oxide photocatalyst surface. It has been confirmed that the process will proceed.

On the other hand, the ability of titanium oxide to decompose harmful substances greatly varies depending on the type of titanium oxide. For example, conventionally, for the purpose of improving whiteness and opacity, titanium oxide has been widely used as an internal pigment for papermaking.The internal titanium oxide for papermaking has a large particle diameter of 0.1 to 0.2 microns. Therefore, the specific surface area was as low as about 10 m ² / g, and it was recognized that the photocatalytic decomposition ability of high-concentration gas-phase harmful substances was low.

Therefore, the present inventor has conducted a detailed investigation on the photocatalytic decomposition ability of internally added titanium oxide powder for papermaking, and
It has been found that, if it is a gas phase harmful substance of m order or less, the titanium oxide powder for papermaking has the ability to decompose gas phase harmful substance efficiently by near-ultraviolet light irradiation.

However, titanium oxide internally added for papermaking is used together with a binder such as polyvinyl alcohol and latex.
Coating on paper, plastic, non-woven fabric, etc.
In the case of a sheet, the binder fixes the titanium oxide fine particles to the base material, but also covers the surface of the titanium oxide fine particles at the same time, so that the gas phase harmful substance can not be adsorbed on the surface of the titanium oxide fine particles, It was confirmed that the photocatalytic decomposition ability was not sufficiently exhibited.

In order to improve the photocatalytic decomposition ability, the average particle diameter is 0.002 to 0.05 μm and the specific surface area is 100 to
Ultrafine titanium oxide of 350 m ² / g has been developed and is being put to practical use. However, ultrafine titanium oxide has a very high photocatalytic decomposition ability and decomposes organic compounds that come into contact with it, so it is coated on paper, plastic, nonwoven fabric, and other base materials together with binders such as polyvinyl alcohol and latex. When formed into a sheet, the binder and the base material are decomposed in a short time, so that it has been difficult to keep the ultrafine titanium oxide fixed on the base material.

Japanese Patent Application Laid-Open No. 9-31335 describes a resin composition in which a mixture of a titanium oxide photocatalyst coated with a porous inorganic substance and an inorganic deodorizing adsorbent is mixed with an organic resin. However, in this method, when coating the titanium oxide photocatalyst with the porous inorganic substance, 550
A calcination step of heat treatment at 1 ° C. for 1 hour was required, and the titanium oxide photocatalyst coated with a porous inorganic substance was taken out as a powder and then blended with an organic resin, which was complicated.

Further, JP-A-9-234375 discloses a photoreactive harmful substance remover comprising a photoreactive semiconductor, colloidal silica, and a thermoplastic polymer emulsion. However, in general, a film formed from a thermoplastic polymer emulsion has a thickness of 400 nm, which is effective for photocatalytic ability.
The photocatalytic effect cannot be sufficiently exhibited due to the low transmittance to the following near ultraviolet rays. Also, when the colloidal silica solution and the thermoplastic polymer emulsion are mixed, gelation occurs, the light is reflected, and the amount of light reaching the titanium oxide surface through the composite film of the colloidal silica and the thermoplastic polymer emulsion is reduced. As a result, it was found that the titanium oxide fine particles had a disadvantage that the photocatalytic function was reduced. Further, in this publication, a detailed description of an appropriate mixing ratio of the photoreactive semiconductor and colloidal silica, an appropriate addition ratio of the thermoplastic polymer emulsion to the photoreactive semiconductor and colloidal silica mixture, and an order of addition thereof are given. Absent. However, as a result of the inventor's intense research, it has been found that for a mixture of titanium oxide fine particles and an inorganic binder made of silica or alumina sol, there is an appropriate addition ratio and an addition order of the organic polymer binder. Was confirmed.

[0013]

The titanium oxide fine particles having an average particle diameter of about several microns exist in a suspended state in the aqueous titanium oxide coating composition. The fine particles aggregate and settle, forming a hard sediment. Agglomerates remain in the aqueous titanium oxide coating composition even if this is re-stirred.Therefore, when such a coating composition is applied and dried on a sheet such as paper, non-woven fabric, plastic film, etc. Agglomerates remain. For this reason, a titanium oxide coated paper having excellent smoothness cannot be obtained, and a problem occurs when a printing process is performed.

[0014] In view of such circumstances, an object of the present invention is to:
An object of the present invention is to provide a water-based titanium oxide coating composition having excellent storage stability and photodegradability.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to provide a water-based titanium oxide coating composition comprising fine powder of titanium oxide and a binder, wherein the binder is selected from silica sol and alumina sol. A titanium oxide fine powder and the inorganic binder in a weight ratio of 5: 1 to 1: 5, and a compounding ratio of the organic polymer binder. Is 3 to 25% by weight based on the total solid content of the water-based titanium oxide coating composition, and the viscosity of the water-based titanium oxide coating composition at 20 ° C measured by a B-type rotational viscometer is 200 to 150%.
The problem was solved by adjusting to be 0 cps.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The titanium oxide used in the present invention is a titanium oxide obtained by a method of purifying from a mineral or a method of chemically synthesizing one that can exist alone by interacting with water. Including. Specifically, titanium oxide or hydroxide, which is called hydrous titanium oxide, hydrated titanium oxide, metatitanic acid, orthotitanic acid, and titanium hydroxide, particularly those having many hydroxyl groups on the surface are preferable . The titanium oxide used in the present invention can be produced by the following method. For example, a method (hydrolysis method) of hydrolyzing titanyl sulfate, titanium chloride, an organic titanium compound, and the like, if necessary, in the presence of seeds for nucleation,
A method in which an alkali agent is added to titanyl sulfate, titanium chloride, an organic titanium compound, etc. to neutralize them (neutralization method) while coexisting with seeds for nucleation as necessary. A phase oxidation method (gas phase oxidation method), a method of firing titanium oxide obtained by a hydrolysis method and a neutralization method (a firing method), and the like can be given. In addition, pure titanium oxide particles obtained by chemically modifying the surface of pure titanium oxide may be used as long as the photocatalytic function is activated by appropriate radiation.

One of the important factors which determine the photodegradability, which is the object of the present invention, is that titanium oxide fine powder and titanium oxide composite particles formed from silica or alumina sol during the drying process of the titanium oxide-containing paint. And in the delicate bond balance between the titanium oxide composite particles and the organic polymer binder, the resolution is improved by more contact of the titanium oxide fine particles with the decomposed substance. The larger the specific surface area, the better. The specific surface area of the titanium oxide according to the present invention can be easily measured with a BET surface area measuring device. However, in consideration of practical resolution, the preferable specific surface area of the fine titanium oxide powder according to the present invention is 10 to 350 m ² / g. It is. Also, most titanium oxides do not have porosity and can be simply filled with a small particle size. The preferred particle size of the primary X-ray particles of the titanium oxide fine powder according to the present invention is 2
The diameter of the secondary particles formed by agglomeration of the primary particles is preferably 0.1 to 5 microns.

In the present invention, the mixing ratio of the titanium oxide fine powder and the silica sol or alumina sol is one of the important factors which determine the effect of the present invention. That is, the mixing ratio determines the structure and function of the titanium oxide composite particles formed in the drying step. The mixing ratio of the titanium oxide fine powder and the silica sol or alumina sol needs to be 5: 1 to 1: 5 by weight.

As the organic polymer binder added to the titanium oxide-containing layer according to the present invention, a water-soluble organic polymer compound, a thermoplastic polymer emulsion, or a mixture thereof is used. Examples of the water-soluble organic polymer compound include starch, modified starch, polyvinyl alcohol, modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, polyacrylamide, cluster dextrin, chitosan, alginate, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose. . In order to increase the transmittance, it is preferable that the reflection, scattering and absorption be as small as possible. In that respect, polyvinyl alcohol and polyacrylamide which are completely dissolved in water are preferable. As the thermoplastic polymer emulsion, acrylic resin, styrene-acryl copolymer, styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, polypropylene and the like can be used.

The addition ratio of the organic polymer binder to the mixture of the titanium oxide fine particles and the inorganic binder selected from silica or alumina sol must be 2 to 25% by weight based on the total solid content of the paint. If it is less than 2% by weight, the binding between the titanium oxide fine particles and the titanium oxide composite particles formed from silica or alumina sol and the fixation to the support are insufficient. When the content exceeds 25% by weight, the binding power increases, but the transmitting power of the active radiation decreases, and the photodecomposition ability decreases.

In the aqueous titanium oxide coating composition of the present invention, a fine powder of titanium oxide is dispersed in water together with a dispersant, and then a colloidal solution of silica or alumina is added at a fixed ratio to titanium oxide and stirred for several hours. Then, an organic polymer binder having a certain concentration and viscosity is added and stirred, and the viscosity of the finally obtained water-based titanium oxide coating composition obtained at 20 ° C. by a B-type rotational viscometer is 200. ~ 1500
Adjust the viscosity to be cps. The viscosity of the aqueous titanium oxide coating composition at 20 ° C. measured by a B-type rotational viscometer is 200.
If it is less than cps, the titanium oxide fine particles will coagulate and precipitate during long-term storage to form a hard deposit. On the other hand, when it exceeds 1500 cps, an interaction between colloidal silica or colloidal alumina in the coating composition and the organic polymer binder is apt to occur, whereby the fluidity of the coating decreases and gelation occurs.

Radiation that activates the photocatalytic function is usually
Ultraviolet light of 400 nm or less.

The water-based titanium oxide coating composition according to the present invention is applied as a titanium oxide-containing layer on a support. Alternatively, a titanium oxide-containing layer may be provided on both sides of the support. The photocatalytic efficiency can be maximized. When the coating amount of the support of the titanium oxide-containing layer is to consider transmission efficiency of ultraviolet is desirably 0.1 to 10 g / m ² on one side, most preferred is 1 to 5 g / m ^2. If desired, an under layer may be provided between the support and the titanium oxide-containing layer to improve the adhesiveness.

The aqueous titanium oxide coating composition of the present invention can be applied to a support by a method of impregnating with a conventional size press, a gate roll size press, a film transfer type size press, a roll coater, a rod ( Bar) Coating method using a coater such as a coater, a blade coater, a spray coater, an air doctor (knife) coater, and a curtain coater in the same manner as in a general coating process, together with a small amount of other appropriate binder if desired. Is mentioned. In particular, in the impregnation method, the support may be wetted in advance.

The support according to the present invention is not particularly limited as long as the aqueous titanium oxide coating composition of the present invention can be applied thereto, but is mainly made of paper composed of vegetable fibers and mainly synthetic resin (fiber). A structured nonwoven fabric, plastic film, or the like is used. As the plant fiber used for the support material according to the present invention, wood such as chemical pulp such as kraft pulp, sulfite pulp, and alkali pulp from softwood and hardwood, semi-chemical pulp, semi-mechanical pulp, and mechanical pulp Fiber, mulberry, mitsumata,
In addition to vegetable non-wood fibers such as straw, kenaf, bamboo, linter, bagasse, and espart, regenerated fibers such as rayon and processed natural fibers such as cellulose derivative fibers may be used.

Further, olefin resins such as polyethylene and polypropylene, polyester resins such as declon, polyvinyl acetate, ethylene-vinyl acetate copolymer resin, polyamide resins such as nylon, polyacrylonitrile, acrylan, auron, dynel, Thermoplastic synthetic resin fibers made of acrylic resin such as Berel, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl ether, polyvinyl ketone, polyether, polyvinyl alcohol resin, diene resin, polyurethane resin, etc., phenol resin In addition to thermosetting synthetic resin fibers such as furan resin, urea resin, melamine resin, aniline resin, unsaturated polyester resin, alkyd resin, and epoxy resin, silicone-based fibers, fluorine-based fibers, and gold such as stainless steel wool. Fibers, various glass fibers. The fiber group used in the present invention may be of a single type or a combination of two or more types.

Further, flame retardancy can be imparted by adding a flame retardant to the support. Examples of the flame retardant include guanidine sulfamate, guanidine phosphate, guanidine tetraborate, ammonium sulfamate, ammonium phosphate, melamine phosphate, tetrabromobisphenol A, antimony trioxide, aluminum hydroxide, and magnesium hydroxide. Can be As a method of impregnating the flame retardant, the impregnation may be carried out by a size press in a paper making process, or may be added in advance in a stock preparation step to make a paper.

In processing the above-mentioned plant fiber raw material into the support according to the present invention, rosin and its modified product, if desired,
Emulsions of vegetable wax or maleic anhydride, α-olefin, and styrene / acrylate synthetic resins, sizing agents such as alkyl ketene dimer, alkenyl succinic anhydride and stearic anhydride, starch and modified products thereof, guar gum And denatured products thereof, dextrin, carboxymethylcellulose, polyvinyl alcohol, polyethylene oxide, polyethyleneimine, polyacrylamide, polyamide epichlorohydrin, various emulsions (including latex), urea formalin resin, melamine formalin resin, and other paper strength enhancers and binders. Besides, various additives such as a retention aid, a surfactant, an antifoaming agent, a dye, a fluorescent brightener, an antioxidant, and a slime control agent may be added or paper-made. For the paper making of the support, a combination paper machine such as a round net paper machine, a fourdrinier paper machine, a Yankee paper machine, a twin wire paper machine, a hybrid former and a top former can be used.

Further, as the plant fiber used for the support according to the present invention, a water-soluble inorganic substance is allowed to act on the plant fiber before forming into a sheet, and then the inorganic substance-supporting fiber obtained by insolubilizing the inorganic substance with water is supported. May be used. As a method for insolubilizing and supporting a water-soluble inorganic substance on plant fiber (pulp), JP-A-3-146766, JP-A-3-152295, JP-A-4-18193, JP-A-4-24299 , And JP
There is a method described in JP-A-4-57964. That is, the hydrophilic fiber material is impregnated with an aqueous solution containing a water-soluble inorganic compound that reacts with a specific gas or aqueous solution to generate a water-insoluble inorganic substance, and then is contacted with a gas or an aqueous solution that makes these inorganic substances water-insoluble. By doing so, a water-insoluble inorganic substance can be carried inside the fiber material.

The non-woven fabric used for the support according to the present invention may be prepared by suspending the above synthetic resin fibers in water to form a sheet by a papermaking method, resin bonding by resin bonding, needle punching using crossing with needles, The so-called dry method such as stitch bond knitted by yarn or thermal bond bonding by heat, water entanglement method in which high-pressure water is sprayed from a nozzle to entangle the fibers, spun bond to form a sheet while spinning directly, direct spinning In this case, it can be manufactured by a melt blow method or the like in which a sheet is formed while producing fine fibers by applying the principle of spraying. The thickness of the nonwoven fabric,
The porosity, the shape of the void, the degree of porosity, the flexibility, the elasticity, the fluff, the texture, and the like can be adjusted by selecting the above-described production method. Further, in the present invention, since the aqueous treatment is performed, the nonwoven fabric needs to have a certain degree of water wettability, and a web made of hydrophilic fibers is preferable. Further, it is preferable to process the nonwoven fabric by a spun bond or spun lace method from the viewpoint of sheet strength.

[0031]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. The parts by weight described below indicate parts by weight of dry solids.

Example 1 <Preparation of Titanium Oxide Paint Composition> 100 parts by weight of titanium oxide fine powder for papermaking (trade name: Taipaque W-10, manufactured by Ishihara Sangyo) and sodium polycarboxylate (trade name: ARON T) -4
0, manufactured by Toa Gosei Co., Ltd.) was mixed with water, and the mixture was stirred at high speed with a laboratory mixer for 1 hour to disperse fine titanium oxide powder. Next, silica sol (trade name: Snowtex ST-4)
0, Nissan Chemical Co., Ltd.) (160 parts by weight) was added to this dispersion, followed by high-speed stirring for 1 hour to prepare a titanium oxide / silica sol dispersion having a solid content of 52.3%. Further, 34 parts by weight of polyvinyl alcohol (trade name: PVA-117, 16% aqueous solution, made by Kuraray) as a water-soluble organic polymer compound is added to the titanium oxide / silica sol dispersion liquid, and slowly added so as not to form bubbles. The mixture was stirred for 30 minutes to prepare a titanium oxide coating composition. At this time, the compounding ratio of the organic polymer binder was 11.5% by weight based on the total solid content of the coating composition, and the concentration of the coating composition was 3%.
Viscosity at 8.8%, 20 ° C, measured by a B-type rotational viscometer (Tokyo Keiki B-type viscometer, using the same measuring device as below) is 1500 cp.
s. The coating composition was allowed to stand at 20 ° C. for 30 days. Thirty days later, when the coating composition was observed, no precipitate of titanium oxide was observed at all.

[Example 2] <Preparation of titanium oxide coating composition> Ultrafine titanium oxide fine powder (trade name: FINNTI S-150, manufactured by KEMIRA) 1
00 parts by weight and sodium polycarboxylate (trade name: ARON T-
40, manufactured by Toa Gosei Co., Ltd.) was mixed with water, and the mixture was stirred at high speed with a laboratory mixer for 1 hour to disperse the fine titanium oxide powder.
Next, silica sol (trade name: Snowtex ST-4)
0, Nissan Chemical Co., Ltd.) (160 parts by weight) was added to this dispersion, followed by high-speed stirring for 1 hour to prepare a titanium oxide / silica sol dispersion having a solid content of 52.3%. Further, 34 parts by weight of polyvinyl alcohol (trade name: PVA-117, 16% aqueous solution, manufactured by Kuraray) as a water-soluble organic polymer compound is added to the titanium oxide / silica sol dispersion liquid, and slowly added so as not to form bubbles. The mixture was stirred for 30 minutes to prepare a titanium oxide coating composition. At this time, the compounding ratio of the organic polymer binder was 11.5% by weight based on the total solid content of the coating composition, and the concentration of the coating composition was 3%.
8.8%, viscosity at 20 ° C by B-type rotational viscometer is 1000c
ps. The coating composition was allowed to stand at 20 ° C. for 30 days. Thirty days later, when the coating composition was observed, no precipitate of titanium oxide was observed at all.

[Example 3] <Preparation of titanium oxide coating composition> Ultrafine titanium oxide fine powder (trade name: FINNTI S-150, manufactured by KEMIRA) 1
00 parts by weight and sodium polycarboxylate (trade name: ARON T-
40, manufactured by Toa Gosei Co., Ltd.) was mixed with water, and the mixture was stirred at high speed with a laboratory mixer for 1 hour to disperse fine titanium oxide powder.
Next, silica sol (trade name: Snowtex ST-4)
0, Nissan Chemical Co., Ltd.) (160 parts by weight) was added to this dispersion, followed by high-speed stirring for 1 hour to prepare a titanium oxide / silica sol dispersion having a solid content of 52.3%. Furthermore, polyvinyl alcohol (trade name: PVA-117, 16% aqueous solution, water-soluble organic polymer compound) was added to the titanium oxide / silica sol dispersion.
25 parts by weight of Kuraray Co., Ltd., a styrene-butadiene copolymer (trade name: LX407) as a thermoplastic polymer emulsion
9 parts by weight of S-1 (48%, manufactured by Zeon Corporation) were added, and the mixture was stirred slowly for 30 minutes without foaming to prepare a titanium oxide coating composition. At this time, the compounding ratio of the organic polymer binder was 11.5% by weight with respect to the total solid content of the coating composition, the concentration of the coating composition was 43.5%, and the viscosity at 20 ° C measured by a B-type rotational viscometer was 650 cps. Met. The coating composition was allowed to stand at 20 ° C. for 30 days. Thirty days later, when the coating composition was observed, no precipitate of titanium oxide was observed at all.

Example 4 <Preparation of Titanium Oxide Paint Composition> Ultrafine titanium oxide fine powder (trade name: FINNTI S-150, manufactured by KEMIRA) 1
00 parts by weight and sodium polycarboxylate (trade name: ARON T-
40, manufactured by Toa Gosei Co., Ltd.), and 2 parts by weight of water were mixed with water, and the mixture was stirred at high speed with a laboratory mixer for 1 hour to disperse fine titanium oxide powder.
Next, 160 parts by weight of alumina sol (trade name: alumina sol 520, manufactured by Nissan Chemical Industries, Ltd.) was added to the dispersion, and the mixture was stirred at high speed for 1 hour to prepare a titanium oxide / alumina sol dispersion having a solid content of 52.3%. Further, 34 parts by weight of polyvinyl alcohol (trade name: PVA-217, 16% aqueous solution, manufactured by Kuraray) as a water-soluble organic polymer compound is added to the titanium oxide / alumina sol dispersion liquid, and slowly added so as not to form bubbles. The mixture was stirred for 30 minutes to prepare a titanium oxide coating composition. At this time, the compounding ratio of the organic polymer binder was 11.5% by weight based on the total solid content of the coating composition, and the concentration of the coating composition was 38.8%.
%, Viscosity at 20 ° C with a B-type rotational viscometer is 200 cps
Met. The coating composition was allowed to stand at 20 ° C. for 30 days. Thirty days later, when the coating composition was observed, no precipitate of titanium oxide was observed at all.

[Comparative Example 1] <Preparation of titanium oxide coating composition> Ultrafine titanium oxide fine powder (trade name: FINNTI S-150, manufactured by KEMIRA) 1
00 parts by weight and sodium polycarboxylate (trade name: ARON T-
40, manufactured by Toa Gosei Co., Ltd.) was mixed with water, and the mixture was stirred at high speed with a laboratory mixer for 1 hour to disperse fine titanium oxide powder.
Next, silica sol (trade name: Snowtex ST-4)
0, Nissan Chemical) 160 parts by weight to this dispersion
The mixture was stirred at high speed for a time to prepare a titanium oxide / silica sol dispersion having a solid content of 52.3%. Further, a polyvinyl alcohol (trade name: PVA-117, 11% aqueous solution,
34 parts by weight (made by Kuraray Co., Ltd.) were added, and the mixture was slowly stirred for 30 minutes without foaming to prepare a titanium oxide coating composition.
At this time, the compounding ratio of the organic polymer binder was 11.5% by weight based on the total solid content of the coating composition, and the concentration of the coating composition was
36.3%, viscosity at 20 ° C measured by B-type rotary viscometer is 150c
ps. The coating composition was allowed to stand at 20 ° C. for 30 days. Thirty days later, when the coating composition was observed, titanium oxide fine particles were aggregated and settled, and solid deposits were recognized. When this coating composition was re-mixed, applied to high quality paper and dried,
Countless aggregates were found on the sheet surface.

Comparative Example 2 <Preparation of Titanium Oxide Paint Composition> Ultrafine titanium oxide fine powder (trade name: FINNTI S-150, manufactured by KEMIRA) 1
00 parts by weight and sodium polycarboxylate (trade name: ARON T-
(40, Toa Gosei) 2 parts by weight were mixed with water, and the mixture was stirred at a high speed with a laboratory mixer for 1 hour to disperse fine titanium oxide powder. Next, silica sol (trade name: Snowtex ST-4)
0, Nissan Chemical) 160 parts by weight to this dispersion
The mixture was stirred at high speed for a time to prepare a titanium oxide / silica sol dispersion having a solid content of 52.3%. Further, a polyvinyl alcohol (trade name: PVA-117, an 18% aqueous solution,
34 parts by weight (made by Kuraray Co., Ltd.) were added, and the mixture was stirred slowly for 30 minutes without foaming to prepare a titanium oxide coating composition. At this time, the compounding ratio of the organic polymer binder was 11.5% by weight based on the total solid content of the coating composition, and the concentration of the coating composition was 4%.
2.6%, viscosity at 20 ° C by B-type rotational viscometer is 1600c
ps. The coating composition was allowed to stand at 20 ° C. for 30 days. Thirty days later, when the coating composition was observed, no sedimentation of the titanium oxide fine particles was observed, but an interaction occurred between colloidal silica in the coating composition and polyvinyl alcohol as the organic polymer binder, The paint lost its fluidity and gelled.

[0038]

The effects of the present invention will be described below. 1) The titanium oxide coating composition is composed of titanium oxide fine particles, silica or alumina sol, and an appropriate ratio of an organic polymer binder, and the B-type rotational viscosity at 20 ° C. of the finally obtained titanium oxide coating composition is obtained. 200 to 1500c
Since it is adjusted to be ps, an aqueous titanium oxide coating composition having excellent long-term storage stability can be obtained. 2) In the drying step after the application of the titanium oxide coating composition to the support, the composite of titanium oxide fine particles and silica or alumina composed of ultrafine particles having a particle diameter on the order of millimicrons occurs preferentially and the titanium oxide composite Particles are formed,
Subsequently, the binding between the titanium oxide composite particles and the fixation to the support by the organic polymer binder occur, so that the titanium oxide fine powder does not decompose the binder and the support. 3) While the photocatalytic function of the titanium oxide coating composition is high,
Since there is no decomposition of the binder and the support in the titanium oxide-containing layer, paper, a plastic film, a nonwoven fabric,
It can be used for planar materials such as wood, plywood and iron plate, and can also be processed as structures such as corrugates and honeycombs.

Continued on front page F-term (reference) 4G047 CA01 CA02 CC01 CD03 4J038 AA011 EA011 HA211 HA216 HA441 KA20 MA08 MA10 MA15 NA26

Claims (1)

[Claims] An aqueous titanium oxide coating composition comprising at least titanium oxide fine powder and a binder, wherein the binder comprises an inorganic binder selected from silica sol or alumina sol and an organic polymer binder, The compounding ratio of the titanium oxide fine powder and the inorganic binder is 5: 1 to 1: 5 by weight, and the compounding ratio of the organic polymer binder is based on the total solid content of the water-based oxide coating composition. Aqueous titanium oxide coating composition wherein the viscosity of the titanium oxide coating composition measured at 20 ° C. with a B-type rotational viscometer is 200 to 1500 cps.