Coating agent

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a coating agent.

【0002】

[Conventional technology]

Various coating agents containing titanium oxide as a photocatalyst have been conventionally provided, and the form thereof is a low-concentration titanium oxide sol type that is neutral and does not contain an inorganic binder. It is becoming mainstream. This is because the titanium oxide sol type coating agent is excellent in coatability and texture at the time of finishing regardless of the base material.

【0003】

However, these conventional coating agents have problems in terms of fixing property of the coating agent, weather resistance and hardness of the coating film when actually applied outdoors, and it is difficult to ensure sufficient application quality. there were.

【0004】

When coating an organic base material, titanium oxide usually attacks the organic material of the base material when it is active and peels off from the base material. Therefore, an inorganic layer as a spacer is provided between the base material and titanium oxide. Need to form. Also, when coating a non-ferrous metal base material, metal ions eluted from the base material react with titanium oxide, so a spacer is formed between the base material and titanium oxide to prevent the reaction. There is a need.

【0005】

Therefore, in actual construction, it is necessary to form a two-layer coat with an inorganic spacer undercoat layer and a titanium oxide layer.

【0006】

As such an undercoating agent for spacers, a titanium peroxide solution (amorphous titanium oxide solution) that is inorganic and has good compatibility with titanium oxide and does not cause photocatalytic activity at room temperature is generally used.

【0007】

However, due to the binding force of titanium peroxide or titanium oxide itself, the fixing to the base material is slow and the degree of adhesion to the base material is weak, so that the construction efficiency is poor in actual construction, and in an outdoor environment. The durability of the coating film was also low in terms of weather resistance and film hardness. In particular, it was difficult to construct in reality because the fixing was further delayed at low temperatures.

【0008】

Therefore, some conventional coating agents are prepared by blending a small amount of an organic fixing agent to improve the fixability and adhesion between titanium oxide and the base material so that the coating can be performed at room temperature.

【0009】

In addition, some undercoat agents for spacers are also blended with an organic fixing agent to improve the fixability and adhesion to the substrate.

【0010】

Further, as an improved coating agent using titanium oxide, a coating agent mixed with lithium silicate is disclosed in Japanese Patent Application Laid-Open No. 10-237354. Such a coating agent has a molar ratio of titanium oxide to lithium silicate (SiO).₂/ Li₂Lithium silicate having O) of 3.5 is used as a binder, and titanium oxide powder and water are directly mixed with the binder to form a slurry.

【0011】

[Problems to be Solved by the Invention]

However, when a two-layer coating of a spacer undercoat layer and a titanium oxide layer using titanium peroxide is applied, the weather resistance is low in an outdoor environment, and the degree of adhesion is lowered and the coating film is deteriorated over time. Titanium oxide peeled off from the base material even if the surface was touched with a finger, so that the construction quality could not be maintained for a long period of time.

【0012】

In addition, when an organic fixing agent is added to the coating agent, the organic content deteriorates due to the influence of ultraviolet rays and acid rain, and titanium oxide decomposes the organic content when the photocatalyst is activated, thereby achieving the degree of adhesion of titanium oxide. However, the coating film deteriorated over time, and it was not possible to maintain the quality of the sprinkling work for a long period of time.

【0013】

Further, even when an organic fixing agent is blended with the spacer undercoat agent, the organic content is deteriorated due to the influence of ultraviolet rays and acid rain, and the adhesion of titanium oxide is unstable.

【0014】

Further, at low temperature, even when the organic fixing agent is blended in the coating agent or the organic fixing agent is blended in the spacer undercoating agent, the fixability is significantly lowered and the construction is difficult.

【0015】

Further, the coating agent disclosed in JP-A No. 10-237354 has a molar ratio of titanium oxide to lithium silicate (SiO).₂/ Li₂Lithium silicate with O) of 3.5 is used as a binder, and titanium oxide powder and water are directly mixed and made into a slurry. Therefore, titanium oxide is not stable in a dispersed state, and titanium oxide is not stable. Tends to settle, it is difficult to form a uniform coating film, and it is not easy to use.

【0016】

Moreover, since the above-mentioned coating agent has a titanium oxide content of 20% by weight or more, the transparency of the coating film is lacking, the coated surface becomes cloudy, and the appearance is impaired.

【0017】

Further, the coating agent has a rough coating surface unless it penetrates into the inside of the base material, and has low fixability. Therefore, as the base material, the coating material must penetrate into the inside, which is versatile. Was low.

【0018】

Further, the above-mentioned coating agent required more than 12 hours at room temperature for fixing, and was poor in workability.

【0019】

[Means for solving problems]

Therefore, the present invention provides a coating agent containing a mixture of anatase-type titanium oxide dispersion and titanium peroxide as a main component.

【0020】

Further, the coating agent provided with a silicic acid compound added as a bond curing agent or an alcohol added as a dispersion medium is provided.

【0021】

BEST MODE FOR CARRYING OUT THE INVENTION

The coating agent according to the present invention contains a mixture of anatase-type titanium oxide dispersion and titanium peroxide as a main component.

【0022】

Specifically, it is the same as the peroxotitanate aqueous solution (PTA aqueous solution) of titanium peroxide obtained by dropping titanium tetrachloride with aqueous ammonia to precipitate titanium hydroxide and then adding aqueous hydrogen peroxide solution. It is a mixture with anatase-type titanium oxide dispersion (PA sol) obtained by heating an aqueous solution of peroxotitanate. The method for producing the anatase-type titanium oxide dispersion or the titanium peroxide solution is not limited to the above method.

【0023】

A coating agent containing a mixture of anatase-type titanium oxide dispersion and titanium peroxide as a main component can satisfactorily activate the photocatalyst when applied to a substrate, and has a good finish. It can be used as a coating agent.

【0024】

In addition, the coating agent is a mixture of an anatase-type titanium oxide dispersion and a peroxotitanic acid aqueous solution having a titanium content of 0.85 to 1.70% by weight, so that the total titanium content is as low as 1.70% by weight or less. I am trying to do it.

【0025】

This is because when the titanium content of the coating agent is 1.70% by weight or more, the viscosity of the coating agent increases with time, so that it is difficult to apply to the base material and the finish feeling when applied to the base material is reduced. This is because there is a risk, and by setting the titanium content of the coating agent to 1.70% by weight or less, dispersion with a dispersion medium can be performed well, and it becomes easy to apply to the base material, and moreover, it is applied to the base material. It is possible to improve the feeling of finish when this is done.

【0026】

A silicic acid compound may be added to the coating agent as a bond curing agent, and in that case, the fixability to the substrate, the degree of adhesion, and the film hardness can be improved.

【0027】

As the silicic acid compound, inorganic sodium silicate, potassium silicate, and lithium silicate are effective, and lithium silicate is particularly preferable.

【0028】

Further, alcohol may be added to the coating agent as a dispersion medium, and in that case, the finished feeling when applied to the base material can be improved.

【0029】

As the alcohol, ethanol, isopropanol and methanol are effective, and ethanol and isopropanol are particularly preferable.

【0030】

Then, by applying the coating agent to a base material, it is possible to form a highly active, high hardness, high quality inorganic coating film having excellent weather resistance, and various building materials used outdoors and existing coating materials can be formed. It has the versatility to add a photocatalytic function to a building and has the same quick-drying property as general paints, so it can be easily constructed at any time of the year regardless of weather conditions. Moreover, since the photocatalyst activity can be maintained for a long period of time even in a harsh outdoor environment, it is possible to improve the quality and efficiency of the photocatalyst construction and to purify the environment.

【0031】

In particular, the coating agent is mainly composed of a mixture of anatase-type titanium oxide dispersion and titanium peroxide solution, and 3% of lithium silicate having a molar ratio of 7.5 is added as a bond hardening agent, and the entire coating agent is used as a dispersion medium. The best performance is achieved by mixing ethanol so that the alcohol concentration in the volume is 25 vol%.

【0032】

[Example]

Specific examples of the present invention will be described below.

【0033】

(Example 1) The same as the peroxotitanic acid aqueous solution (PTA aqueous solution) of titanium peroxide obtained by dropping titanium tetrachloride with aqueous ammonia to precipitate titanium hydroxide and then adding aqueous hydrogen peroxide solution. A coating agent containing a mixture of anatase-type titanium oxide dispersion and titanium peroxide solution as the main component by mixing with anatase-type titanium oxide dispersion (PA sol) obtained by heating an aqueous peroxotitanic acid solution. Manufactured. The method for producing the peroxotitanic acid aqueous solution and the anatase-type titanium oxide dispersion is not limited to the above method.

【0034】

When a coating agent containing a mixture of anatase-type titanium oxide dispersion and titanium peroxide as a main component was applied to the base material, the photocatalyst could be satisfactorily activated on the surface of the base material, and the finish was completed. It was confirmed that the feeling was good.

【0035】

In particular, when a PTA aqueous solution having a titanium content of 0.85 to 1.70% by weight and a PA sol are mixed so that the total titanium content becomes a low concentration of 1.70% by weight or less, dispersion with a dispersion medium is used. It was confirmed that the above was performed well, the application to the base material became easy, and the finished feeling when applied to the base material was good.

【0036】

(Example 2) A silicic acid compound was added as a bond curing agent to the coating agent of Example 1. As the silicic acid compound, inorganic sodium silicate, potassium silicate, and lithium silicate were used.

【0037】

And the sodium silicate is anhydrous silicic acid (SiO).₂) Content is 24%, anhydrous silicic acid and sodium oxide (N a)₂Molar ratio to O) (SiO₂/ Na₂The one with O) set to 3.8 was used.

【0038】

In addition, potassium silicate is anhydrous silicic acid (SiO).₂) Content is 20%, silicic acid anhydride and potassium oxide (K)₂Molar ratio to 0) (SiO₂/ K₂The one with 0) set to 3.5 was used.

【0039】

Lithium silicate is anhydrous silicic acid (SiO).₂) Content is 20%, anhydrous silicic acid and lithium oxide (Li)₂Molar ratio to 0) (SiO₂/ Li₂The ones with 0) set to 3.5 and 7.5 were used.

【0040】

Then, a silicic acid compound in the same amount as the titanium oxide content of the coating agent is mixed in the coating agent, and each is applied to the base material, and the fixability, adhesion, film hardness, activity, and finish of each are applied. I compared the feelings. A 10 cm square tile was used as the base material, a two-layer coating method was adopted as the coating method, and a peroxotitanic acid aqueous solution was applied as the undercoating agent for the spacer, and 50 to 100 g / m.²The coating amount was applied to the surface of the base material and dried at room temperature to form a coating film on the surface of the base material.

【0041】

That is, the following five types were compared. (Subject Example 1) An anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight were mixed at a ratio of 3: 7. (Comparative Example 1) To Example 1, the same amount of sodium silicate as the titanium content of 0.85% by weight was added. (Comparative Example 2) Potassium silicate in the same amount as 0.85% by weight of titanium content was added to Target Example 1. (Comparative Example 3) Lithium silicate having a molar ratio of 3.5, which is the same amount as the titanium content of 0.85% by weight, was added to Target Example 1. (Comparative Example 4) Lithium silicate having a molar ratio of 7.5, which is the same amount as the titanium content of 0.85% by weight, was added to Target Example 1.

【0042】

Table 1 shows the results of comparison of the above five types of coating agents.

【0043】

[table 1]

<img file="JP2003138162A_D0001.tif" />【0044】

Here, the fixability is evaluated by the time required until titanium oxide cannot be removed from the surface of the base material even if the coating film is touched indoors at 20 ° C. Those in which titanium oxide cannot be removed within an hour are indicated by Δ, and those in which titanium oxide cannot be removed in 24 hours or more are indicated by ×.

【0045】

In addition, the degree of adhesion is evaluated by a peeling test (JISX cut tape method) with an adhesive tape 24 hours after application, and the coating film is visually observed with a loupe, and no change is observed in the coating film. Those with Yes are indicated by Yes, and those with even a slight film breakage are indicated by ×.

【0046】

The film hardness is evaluated by a pencil scratch test (JIS hand-scraping method) 24 hours after application. Pencil hardness of 5H or more is 0, 2-4H is , and 2H or less. Things are represented by x.

【0047】

In addition, the activity is determined by irradiating the coated surface with ultraviolet rays in advance using an ultraviolet irradiation device (1 mW / cm).²), Then apply the test solution methylene blue diluted to 10 mg / liter (anhydrous weight standard) with distilled water, and irradiate with ultraviolet rays again after drying (1 mW / cm).²), And it is evaluated by the fading reaction at that time, and according to the standard of the Photocatalyst Council, if methylene blue is not visually colored after 1 hour, methylene blue is observed even after 1 hour or more. Things are represented by x.

【0048】

In addition, the feeling of finish is evaluated visually and by touch based on target example 1. Those equivalent to target example 1 are Yes, and those inferior to target example 1 but not causing a finish problem are . , Those that are inferior to Target Example 1 and cause problems in finish are indicated by x.

【0049】

When the above five types of coating agents were compared, it was found that the surface of Target Example 1 was scratched by the touch of a finger even after 24 hours had passed, but in Comparative Examples 1 to 4, the surface was scratched. It was found that it had the same quick-drying property as general quick-drying paint.

【0050】

Regarding the degree of adhesion, it was observed that the coating film was peeled off in Target Example 1, and that some of the coating film was peeled off in Comparative Example 3, but it was completely coated in Comparative Examples 1, 2, and 4. It was confirmed that the film did not peel off. It is considered that this is because in Comparative Example 3, the film becomes brittle as the coating film itself becomes hard due to the bond curing agent.

【0051】

Regarding the film hardness, it was confirmed that the pencil hardness was 1H or less in Target Example 1, but it was confirmed that a hard coating film having a pencil hardness of 5H or more was formed in Comparative Examples 1 to 4. Was done.

【0052】

Regarding the activity, in Target Example 1, no coloring of methylene blue was observed within 1 hour, and it was confirmed that the photocatalyst was well activated, and in Comparative Example 4, methylene blue was also observed within 1 hour. It was confirmed that the photocatalyst was well activated, but in Comparative Examples 1 to 3, methylene blue was colored even after 1 hour, and the photocatalyst was activated. Was found to be decreasing.

【0053】

Regarding the finished feeling, in Comparative Examples 1 to 3, it was observed that the coating film was uneven and rough, and in Comparative Example 4, although it was inferior to the finished feeling of Target Example 1, there was no problem in practical use. It was recognized that there was.

【0054】

From the above, when comparing the above five types of coating agents, it is recognized that Comparative Example 4 has quick-drying property, is excellent in activity, and can form a coating film having high adhesion and high hardness. Was done.

【0055】

That is, it was found that lithium silicate having a molar ratio of 7.5 is suitable as the bond curing agent for the coating agent.

【0056】

(Example 3) Next, a product in which the amount of lithium silicate having a molar ratio of 7.5 added to the coating agent was changed was produced, and each was applied to a base material to obtain the fixability, adhesion, film hardness, and the like. The activity and finish were compared. As in Example 2, a 10 cm square tile was used as the base material, a two-layer coating method was adopted as the coating method, and a peroxotitanic acid aqueous solution was applied as the undercoating agent for the spacer, and 50 to 100 g. / m²The coating amount was applied to the surface of the base material and dried at room temperature to form a coating film on the surface of the base material. Lithium silicate is anhydrous silicic acid (SiO).₂) Content is 20%, anhydrous silicic acid and lithium oxide (Li)₂Molar ratio to 0) (SiO₂/ Li₂The one with 0) set to 7.5 was used.

【0057】

That is, the following five types were compared. (Subject Example 1) An anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight were mixed at a ratio of 3: 7. (Comparative Example 5) 2% (0.45% by weight) of lithium silicate having a molar ratio of 7.5 was added to Target Example 1. (Comparative Example 6) 3% (0.68% by weight) of lithium silicate having a molar ratio of 7.5 was added to Target Example 1. (Comparative Example 7) 4% (0.91% by weight) of lithium silicate having a molar ratio of 7.5 was added to Target Example 1. (Comparative Example 8) 5% (1.10% by weight) of lithium silicate having a molar ratio of 7.5 was added to Target Example 1.

【0058】

Table 2 shows the results of comparison of the above five types of coating agents.

【0059】

[Table 2]

<img file="JP2003138162A_D0002.tif" />【0060】

When the above five types of coating agents were compared, it was found that the surface of Target Example 1 was scratched by the touch of a finger even after 24 hours had passed, and that of Comparative Example 5 was scratched by the touch of a finger. It was found that it took about 2 hours to disappear, but in Comparative Examples 6 to 8, it was found that the paint had a quick-drying property equivalent to that of a general quick-drying paint.

【0061】

Regarding the degree of adhesion, it was confirmed that the coating film was peeled off in Target Example 1, but the coating film was not peeled off at all in Comparative Examples 5 to 8.

【0062】

Regarding the film hardness, it was found that the pencil hardness was 1H or less in Target Example 1 and the pencil hardness was about 4H in Comparative Example 5, but the pencils in Comparative Examples 6 to 8 It was confirmed that a hard coating film having a hardness of 5H or more was formed.

【0063】

Regarding the activity, methylene blue was not colored within 1 hour in Target Example 1, and it was confirmed that the photocatalyst was well activated, and Comparative Examples 5 to 8 also had 1 No coloring of methylene blue was observed within an hour, and it was confirmed that the photocatalyst was well activated. However, it was found that the activity decreased in proportion to the amount of lithium silicate added.

【0064】

In addition, regarding the finished feeling, it was recognized that there is no problem in practical use in Comparative Examples 5 to 8 although it is inferior to the finished feeling of Target Example 1. However, it was found that the coating film had spots in proportion to the amount of lithium silicate added.

【0065】

From the above, when comparing the above five types of coating agents, even in Comparative Example 5, the function as a coating agent can be sufficiently exhibited, but Comparative Examples 6 and 7 have good fixability, activity, and finish feeling. Was recognized.

【0066】

That is, it can be seen that the amount of lithium silicate having a molar ratio of 7.5 added as a bond curing agent for the coating agent is preferably in the range of 3% (0.68% by weight) to 4% (0.91% by weight). When this is expressed by the content ratio of lithium silicate to the titanium content of the coating agent, it is in the range of 0.8 to 1.1.

【0067】

(Example 4) Next, a coating agent to which various alcohols were added was produced, and each was applied to a base material, and the activity and finish feeling of each were compared. A 10 cm square tile is used as the base material, and a one-layer coating method is used as the coating method, and 50 to 100 g / m.²The coating amount was applied to the surface of the base material and dried at room temperature to form a coating film on the surface of the base material. Further, as the alcohol, ethanol, isopropanol and methanol were used.

【0068】

That is, the following four types were compared. (Subject Example 1) An anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight were mixed at a ratio of 3: 7. (Comparative Example 9) A peroxotitanic acid aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of a 50 vol% aqueous solution of ethanol diluted with purified water of an ion exchange resin. And were mixed in a ratio of 3: 7. In this case, the alcohol concentration in the total volume of the coating agent is 25 vol%. (Comparative Example 10) A peroxotitanium aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of 50 vol% aqueous solutions of isopropanol diluted with purified water of an ion exchange resin. And were mixed in a ratio of 3: 7. In this case, the alcohol concentration in the total volume of the coating agent is 25 vol%. (Comparative Example 11) A peroxotitanic acid aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of a 50 vol% aqueous solution of methanol diluted with purified water of an ion exchange resin. And were mixed in a ratio of 3: 7. In this case, the alcohol concentration in the total volume of the coating agent is 25 vol%.

【0069】

Table 3 shows the results of comparison of the above four types of coating agents.

【0070】

[Table 3]

<img file="JP2003138162A_D0003.tif" />【0071】

When the above four types of coating agents were compared, it was confirmed that in the subject example 1, methylene blue was not colored within 1 hour, and the photocatalyst was well activated. In Comparative Examples 9 to 11, methylene blue was not colored within 1 hour, and it was confirmed that the photocatalyst was well activated.

【0072】

In addition, regarding the finished feeling, it was confirmed that in Comparative Examples 9 and 10, the coating film became smoother than in Target Example 1, but in Comparative Example 11, the coating film became slightly cloudy.

【0073】

From the above, when the above four types of coating agents were compared, it was confirmed that Comparative Examples 9 and 10 had good activity and a feeling of finish.

【0074】

That is, it can be seen that ethanol and isopropanol are preferable as the dispersion medium of the coating agent. Considering the odor of alcohol, ethanol is more preferable.

【0075】

(Example 5) Next, an alcohol aqueous solution in which the concentration of alcohol to be mixed with the coating agent was changed was produced, and the respective states were observed. As the alcohol, ethanol and isopropanol were used.

【0076】

That is, the states of the following two types were observed at various concentrations. (Comparative example 12) 5% of lithium silicate having a molar ratio of 7.5 was added to an aqueous ethanol solution diluted with ion exchange resin purified water to various concentrations. In this case, the alcohol concentration in the total volume of the alcohol aqueous solution was set to 20 vol% to 80 vol%. (Comparative Example 13) 5% of lithium silicate having a molar ratio of 7.5 was added to an isopropanol aqueous solution diluted with ion exchange resin purified water to various concentrations. In this case, the alcohol concentration in the total volume of the alcohol aqueous solution was set to 20 vol% to 80 vol%.

【0077】

Table 4 shows the results of observations regarding the above alcohol aqueous solution.

【0078】

[Table 4]

<img file="JP2003138162A_D0004.tif" />【0079】

When the above alcohol aqueous solution was observed, when the alcohol aqueous solution concentration was 30 vol% or less in both Comparative Example 12 and Comparative Example 13, lithium silicate was dispersed without condensation and maintained a stable state, whereby lithium silicate was observed. It was confirmed that the function as a bond hardening agent was not impaired.

【0080】

That is, it can be seen that ethanol and isopropanol to be mixed as a dispersion medium of the coating agent are preferably mixed so that the alcohol concentration is 30 vol% or less with respect to the total volume of the coating agent in order not to condense lithium silicate.

【0081】

(Example 6) Next, those having an alcohol concentration of 30 vol% or less based on the total volume of the coating agent were produced, and each was applied to a base material, and the dispersibility of each was compared. A 10 cm square tile was used as the base material, a two-layer coating method was adopted as the coating method, and a peroxotitanic acid aqueous solution was applied as the undercoating agent for the spacer, and 50 to 100 g / m.²The coating amount was applied to the surface of the base material and dried at room temperature to form a coating film on the surface of the base material. Further, as the alcohol, ethanol was used.

【0082】

That is, the states of each of the following five types were observed. (Comparative Example 14) A peroxotitanic acid aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of a 60 vol% aqueous solution having an ethanol content diluted with ion exchange resin purified water. And were mixed at a ratio of 3: 7, and 3% of lithium silicate having a molar ratio of 7.5 was added. In this case, the alcohol concentration in the total volume of the coating agent is 30 vol%. (Comparative Example 15) A peroxotitanic acid aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of a 50 vol% aqueous solution of ethanol diluted with purified water of an ion exchange resin. And were mixed at a ratio of 3: 7, and 3% of lithium silicate having a molar ratio of 7.5 was added. In this case, the alcohol concentration in the total volume of the coating agent is 25 vol%. (Comparative Example 16) A peroxotitanic acid aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of a 40 vol% aqueous solution having an ethanol content diluted with ion exchange resin purified water. And were mixed at a ratio of 3: 7, and 3% of lithium silicate having a molar ratio of 7.5 was added. In this case, the alcohol concentration in the total volume of the coating agent is 20 vol%. (Comparative Example 17) A peroxotitanic acid aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of a 30 vol% aqueous solution having an ethanol content diluted with ion exchange resin purified water. And were mixed at a ratio of 3: 7, and 3% of lithium silicate having a molar ratio of 7.5 was added. In this case, the alcohol concentration in the total volume of the coating agent is 15 vol%. (Comparative Example 18) A peroxotitanic acid aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of a 20 vol% aqueous solution having an ethanol content diluted with ion exchange resin purified water. And were mixed at a ratio of 3: 7, and 3% of lithium silicate having a molar ratio of 7.5 was added. In this case, the alcohol concentration in the total volume of the coating agent is 10 vol%.

【0083】

Table 5 shows the results of comparison of the above five types of coating agents.

【0084】

[Table 5]

<img file="JP2003138162A_D0005.tif" />【0085】

Here, the dispersibility is evaluated by visually observing the coating film with a loupe, and those without spots are represented by Yes, those with slight spots are represented by Δ, and those with spots are represented by ×. ing.

【0086】

When the above five types of coating agents were compared, it was found that no spots were observed in Comparative Examples 14 to 17, but slight spots were observed in Comparative Example 18.

【0087】

That is, it can be seen that the alcohol to be mixed as the dispersion medium of the coating agent is preferably mixed so that the alcohol concentration is 15 vol% to 30 vol% with respect to the total volume of the coating agent. Considering the dispersion stability of lithium silicate as a bond curing agent, the alcohol to be mixed as the dispersion medium of the coating agent should be mixed so that the alcohol concentration is 15 vol% to 25 vol% with respect to the total volume of the coating agent. Is preferable.

【0088】

(Example 7) Next, 3% (0.68% by weight) or 4% (0.91% by weight) of lithium silicate having a molar ratio of 7.5 was added to the coating agent as a binding curing agent, and the alcohol concentration was 25 vol% as a dispersion medium. A mixture of ethanol was produced so as to be, and each was applied to a base material, and the fixability, adhesion, film hardness, activity, finish feeling, and durability of each were confirmed. A 10 cm square tile was used as the base material, a two-layer coating method was adopted as the coating method, and a peroxotitanic acid aqueous solution was applied as the undercoating agent for the spacer, and 50 to 100 g / m.²The coating amount was applied to the surface of the base material and dried at room temperature to form a coating film on the surface of the base material.

【0089】

That is, the following three types were confirmed. (Subject Example 1) An anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight were mixed at a ratio of 3: 7. (Comparative Example 19) A peroxotitanic acid aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of a 50 vol% aqueous solution of ethanol diluted with purified water of an ion exchange resin. And were mixed at a ratio of 3: 7, and 3% of lithium silicate having a molar ratio of 7.5 was added. In this case, the alcohol concentration in the total volume of the coating agent is 25 vol%. (Comparative Example 20) A peroxotitanic acid aqueous solution having a titanium content of 0.85% by weight and an anatase-type titanium oxide dispersion having a titanium content of 0.85% by weight, each of which is a mixture of a 50 vol% aqueous solution having an ethanol content diluted with ion exchange resin purified water. And were mixed at a ratio of 3: 7, and 4% of lithium silicate having a molar ratio of 7.5 was added. In this case, the alcohol concentration in the total volume of the coating agent is 25 vol%.

【0090】

The results of confirmation for the above three types of coating agents are shown in Tables 6 and 7.

【0091】

[Table 6]

<img file="JP2003138162A_D0006.tif" />【0092】

[Table 7]

<img file="JP2003138162A_D0007.tif" />【0093】

Here, the durability is evaluated by conducting an accelerated weather resistance test with a sunshine weather meter for a total of 1000 hours, and before 1000 hours have passed, changes can be seen on the surface of the coating film by visual inspection with a loupe and touch. Those that cannot be displayed are indicated by Yes, those that show peeling of the coating film or chalking phenomenon are indicated by ×, and after 1000 hours, not only by visual inspection and touch with a loupe, but also by pulling with adhesive tape. A peeling test was also carried out, and those in which no change was observed in the coating film were indicated by Yes, and those in which the coating film was peeled off or a chalking phenomenon was observed were indicated by ×.

【0094】

When the above three types of coating agents were compared, it was found that the surface of Target Example 1 was scratched by the touch of a finger even after 24 hours had passed, but in Comparative Examples 19 and 20, it was general. It was found that it had the same quick-drying property as the quick-drying paint.

【0095】

Regarding the degree of adhesion, it was confirmed that the coating film was peeled off in Target Example 1, but the coating film was not peeled off at all in Comparative Examples 19 and 20.

【0096】

Regarding the film hardness, it was confirmed that the pencil hardness was 1H or less in Target Example 1, but it was confirmed that a hard coating film having a pencil hardness of 5H or more was formed in Comparative Examples 19 and 20. ..

【0097】

Regarding the activity, methylene blue was not colored within 1 hour in Target Example 1, and it was confirmed that the photocatalyst was well activated, and in Comparative Examples 19 and 20, it was also within 1 hour. No coloring of methylene blue was observed, and it was confirmed that the photocatalyst was well activated. However, it was found that the activity of Comparative Example 19 was higher than that of Comparative Example 20.

【0098】

Regarding the feeling of finish, it was confirmed that Comparative Examples 19 and 20 had the same feeling of finish as that of Target Example 1.

【0099】

Regarding durability, it was confirmed that no change occurred on the surface of the coating film in Comparative Examples 19 and 20.

【0100】

From the above, it was confirmed that both Comparative Examples 19 and 20 exhibited excellent performance.

【0101】

That is, as the coating agent, 3% to 4% of lithium silicate having a molar ratio of 7.5 was added as a bond curing agent, and ethanol was mixed as a dispersion medium so that the alcohol concentration in the total volume of the coating agent became 25 vol%. Was found to exhibit excellent performance. When this is expressed by the content ratio of lithium silicate to the titanium content of the coating agent, it is in the range of 0.8 to 1.1.

【0102】

(Example 8) Next, 3% (0.68% by weight) of lithium silicate having a molar ratio of 7.5 was added to the coating agent as a bond hardening agent, and the alcohol concentration in the total volume of the coating agent was further increased to 25 vol% as a dispersion medium. A mixture of ethanol is manufactured so as to be, and it is applied to various substrates, and the durability of the coating film (maintenance of adhesion, maintenance of film hardness, maintenance of activity, maintenance of finished surface) by exposure test is performed for each. confirmed. As the base material, tiles, glass, acrylic plates, water-based paint (acrylic resin) coated steel plates, lacquer coated steel plates, polyurethane coated fireproof exterior wall materials, ALC concrete coated plates, and exterior wall siding, which are outdoor building materials, are used as necessary. Depending on the primer treatment, 50 to 100 g / m was applied to the undercoat agent for spacers coated with an aqueous peroxotitanic acid solution.²The coating amount was applied to the surface of the base material and dried at room temperature to form a coating film on the surface of the base material.

【0103】

Table 8 shows the results of confirmation of the above coating agents.

【0104】

[Table 8]

<img file="JP2003138162A_D0008.tif" />【0105】

As the durability of the coating film by the exposure test, each item of maintaining adhesion to the substrate, maintaining film hardness, maintaining activity, and maintaining the finished surface was confirmed.

【0106】

Here, to maintain adhesion, the adhesion of samples left outdoors is evaluated every three months for one year, and those that do not show changes are indicated by Yes, and those that show changes are indicated by ×. There is.

【0107】

To maintain the film hardness, the film hardness of the sample left outdoors is evaluated every three months for one year. Those that do not show any change are indicated by Yes, and those that show change are indicated by ×. There is.

【0108】

For activity maintenance, the activity of samples left outdoors is evaluated every 3 months for 1 year, and those with no change are indicated by Yes and those with changes are indicated by ×.

【0109】

In addition, to maintain the finished surface, the finished feeling of the sample left outdoors is evaluated every three months for one year, and those that do not show any change are indicated by Yes, and those that show change are indicated by ×. ..

【0110】

As a result of confirming the above coating agents, it was confirmed that good results were obtained for all the substrates in terms of the durability of the coating film (maintenance of adhesion, maintenance of film hardness, maintenance of activity, maintenance of finished surface) by the exposure test. .. In addition, the antifouling effect of the self-cleaning function was also recognized.

【0111】

[Effect of the invention]

The present invention is carried out in the form as described above, and has the effects described below.

【0112】

That is, in the present invention according to claim 1, since the coating agent contains a mixed solution of anatase-type titanium oxide dispersion and titanium peroxide as the main component, the photocatalyst is satisfactorily activated when applied to the substrate. Moreover, it is possible to obtain a coating agent having a good finish feeling.

【0113】

Further, in the present invention according to claim 2, since the silicic acid compound is added as the bond curing agent, the fixability to the substrate, the degree of adhesion and the film hardness can be improved.

【0114】

Further, in the present invention according to claim 3, since alcohol is added as a dispersion medium, the finished feeling when applied to the base material can be improved.