KR101136014B1 - Photocatalytic coating composition having water repellent and air-cleaning activity, containing titanium dioxide coated by hydroxy-apatite - Google Patents

Abstract

The present invention relates to a photocatalyst coating composition comprising titanium dioxide coated with hydroxyapatite, wherein the photocatalyst coating composition is 0.43 to 4.3% by weight of hydroxyapatite coated silica, 0.43 to 0.49% by weight of silica binder, and 0.043 to thickener. It is composed of 0.43% by weight, dispersant 0.043 ~ 0.43% by weight, preservative 0.043 ~ 0.43% by weight and water 93.92 ~ 99.011% by weight so that it can be used even in the absence of light by using strong adsorption power of hydroxyapatite Titanium dioxide can be completely absorbed and trapped in the environment where light is absorbed, and it can completely decompose harmful gases and harmful organic substances by photocatalytic action of titanium dioxide. To reduce the strength weakening due to water infiltration and to prevent the occurrence of bleaching .

Hydroxyapatite, titanium dioxide, polysiloxane, volatile organics

Description

Photocatalytic coating composition having water repellent and air-cleaning activity, containing titanium dioxide coated by hydroxy-apatite

The present invention relates to a photocatalyst coating composition comprising titanium dioxide coated with hydroxy apatite. More particularly, the present invention uses a strong adsorption force of hydroxy apatite to prevent harmful gases and harmful organic substances even in an environment where no light is present. Titanium dioxide can be completely decomposed by the photocatalytic action of titanium dioxide in the presence of light by adsorption, and it also gives water repellency by applying silica-based water-repellent material that is highly compatible with titanium dioxide. The present invention relates to a photocatalyst coating composition comprising titanium dioxide coated with hydroxy apatite, which reduces the strength weakening due to water penetration and makes it difficult to generate whitening phenomenon.

In the case of concrete products, various recycle materials are used as additives, and various harmful substances eluted to the surface and the debate about its harmfulness have been frequently issued, and the problem of harmfulness to the human body has been continuously raised. For this reason, many attempts have been made to apply photocatalysts to concrete products.

Photocatalyst is hydroxy radical (OH ^-) by the light is the spotlight in recent years as a functional auxiliary material as environmentally friendly materials that can be caused by the superoxide ion decomposition of various organic substances, microorganisms and so on completely indiscriminately. The Japan Photocatalytic Concrete Industry Association has published research reports that it can reduce nitrogen oxides (NO _x ) and sulfur oxides (SO _x ) by 15% by manufacturing photocatalyst-coated concrete products. After 10 years, the surface was kept in a clean state. However, the photocatalyst, which has excellent performance in decomposing organic pollutants, has a disadvantage in that it does not exhibit specific pollutant degrading performance in the absence of light, and thus has a disadvantage in that its functionality is greatly reduced when applied to actual products.

Accordingly, the present invention has been made to solve the problems of the prior art as described above, by coating the hydroxy apatite (TiO ₂ ) with hydroxy apatite excellent in adsorption capacity of contaminants, such as photocatalyst to light energy Adsorb contaminants around titanium dioxide in an environment that cannot be supplied to the environment.When light begins to be supplied, titanium dioxide decomposes the contaminants efficiently and reduces them to nature in a harmless state. The purpose of the present invention is to provide a photocatalyst coating composition comprising titanium dioxide coated with hydroxyapatite, which is applied with a strong silica-based water-repellent material to impart water repellency to reduce strength weakness due to moisture penetration and to prevent whitening phenomenon. It is done.

The photocatalyst coating composition according to the present invention is 0.43 to 4.3% by weight of hydroxyapatite-coated titanium dioxide, silica binder, 0.043 to 0.43% by weight of thickener, 0.043 to 0.43% by weight of dispersant, 0.043 to 0.43% by weight of preservative, and 93.92 to 99.011 of water. In the photocatalyst coating composition composed of weight%,

The silica binder may be silicon hydroxide (Si (OH) ₄ ) or general Si (OR) ₄ (R: C _n H _{2n + 1} , 1 ≤ n ≤ 10), characterized in that included in the range 0.43 ~ 0.49% by weight relative to the total amount of the photocatalyst coating composition.

When the hydroxyapatite-coated titanium dioxide is added at less than 0.43% by weight, it is difficult to exhibit the functionalities such as atmospheric purification and self-cleaning of the photocatalyst, and when added at more than 4.3% by weight, the photocatalyst is originally possessed. By changing the color of the surface of the concrete by the white color present, the aesthetics of the product can be reduced, and the photocatalytic particles agglomerate on the surface of the concrete product to form white agglomerates. It is preferable to add titanium dioxide in the range of 0.43-4.3 weight%.

The silica binder is excellent in miscibility with the photocatalyst, and is preferably added in an amount of 0.43 to 0.49% by weight in order to prevent agglomeration between hydroxyapatite particles and to disperse the titanium dioxide particles, and additionally, 0.043 to 0.43% by weight of a dispersant. It is preferable. It is preferable to use ethanol or methanol here as a dispersing agent.

The thickener uses Xanthan Gum as a component to impart viscosity to the reactants, and if the content is outside the range of 0.043 to 0.43% by weight, the viscosity is too low or too high, which is poor because of poor fluidity and workability. not.

The preservative uses potassium sorbate (potassium sorbate) as an ingredient added to prevent decay in distribution and storage, and if the content is outside the range of 0.043 ~ 0.43% by weight easily decay or photocatalyst performance It is not good because there is problem to degrade.

The water is preferably added 93.92 ~ 99.011% by weight in consideration of economical efficiency, titanium dioxide activity and process smoothness.

On the other hand, it is preferable that the coverage of hydroxy apatite on the titanium dioxide surface is 5 to 36%. If the coverage of the hydroxyapatite on the titanium dioxide surface is less than 5%, the adsorptivity of the contaminants by the hydroxyapatite is difficult to be exhibited. If the hydroxyapatite is more than 36%, the hydroxyapatite covers all the titanium dioxide particles, so This is because performance will be impaired.

In addition, the titanium dioxide is not only difficult to apply titanium dioxide as a paint when the average particle diameter is less than 1nm, it is difficult to use as a photocatalyst due to the reduced light-receiving ability to absorb light as a photocatalyst, titanium dioxide in water Since it is difficult to disperse | distribute particle | grains and it is difficult to make the paint which the photocatalyst is disperse | distributed uniformly, it is preferable that titanium dioxide has an average particle diameter of 1-250 nm.

On the other hand, it is preferable to coat the photocatalyst coating composition according to the present invention on the concrete surface using a spray coating method, dip coating method, roller coating method.

In addition, it is preferable to cure the concrete coated by the above coating method at a temperature range of 18 ~ 150 ℃, less than 18 ℃ has a problem that the hardness of the coated coating is weakened, in the case of more than 150 ℃ sudden This is because there is a risk of cracking of the coating film due to curing.

The concrete hardened by the above method can be concrete products such as block road block, boundary block, raft block, vegetation raft block, braille block and the like.

Hereinafter, the present invention will be described in detail.

First, it has the ability to adsorb organic substances and bacteria, and has a molecular formula of Ca _x (PO ₄ ) _y ? (0H) _z [x = 5z, y = 3z, z = 1 ~ 50]. _In order to coat hydroxyapatite with ₁₀ (PO ₄ ) ₆ (0H) ₂ on titanium dioxide, a condition of analogous liquid is formed to mix a substance subject to Ca ₁₀ (PO ₄ ) ₆ (0H) ₂ . In the composition, NaCl, NaHCO ₃ , KCl, K ₂ HPO ₄ ˜3H ₂ O, MgCl ₂ ˜6H ₂ O, 1mol / dm ³ HCl, CaCl ₂ , Na ₂ SO ₄ , H ₂ NC (CH ₂ OH) ₃ is dissolved to prepare an analogous liquid. Titanium dioxide is added and dispersed in the analog liquid to allow hydroxy apatite to settle on the surface of titanium dioxide constantly while stirring for 1 hour. Thereafter, hydroxyapatite is grown for 24 hours while stirring is stopped. Thus, a titanium dioxide coated with hydroxy apatite evenly coated on the surface can be obtained, which can be heated at 200-300 ° C. for 1 hour to obtain a more stable product. The titanium dioxide used at this time may be any of anatase type, rutile type, and brookite type, and in the present invention, the anatase type P25 type (manufactured by Degusa, Germany) can be used. Use a photocatalyst.

Methanol (CH ₃ OH) or ethanol (CH ₃ CH ₂ OH) is added as a dispersant by mixing a silica-based binder to a slurry of an aqueous solution of hydroxyapatite-coated titanium dioxide prepared by the above method and stirring at low speed. Xanthan Gum as a thickener and potassium sorbate as a preservative are added and stirred at high speed to prepare a photocatalyst coating composition comprising titanium dioxide coated with the hydroxyapatite of the present invention.

Meanwhile, the silica binder may be silicon hydroxide (Si (OH) ₄ ) or general formula Si (OR) ₄ (R: C _n H _{2n + 1} , Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) _4, etc. having 1 ≦ n ≦ 10), and the silica binder is not limited to the above materials, and is represented by -Si-O- as shown in the following molecular formula. All materials capable of forming a Si-polysiloxane bond structure are included.

The silica binder reacts with water to form a polysiloxane-based polymer to immobilize the titanium dioxide particles coated with hydroxyapatite and form a bonding structure of polysiloxane composed of -Si-O-Si-O- as shown below. It will prevent infiltration.

Since the silica binder is cyclized after the curing of the photocatalyst coating composition including the titanium dioxide coated with hydroxyapatite of the present invention, the silica and titanium dioxide are cyclized to block moisture and maintain an ideal state for passing air. It will act to prevent.

Hereinafter, as the photocatalyst coating composition of the present invention, spray coating, dip coating, roller coating method, brush coating method of concrete products such as bochado block, boundary block, rake block, vegetation relief block, braille block, etc. The manufacturing method economically using the method is demonstrated.

After coating the photocatalyst coating composition comprising the titanium dioxide coated with hydroxy apatite of the present invention prepared on the surface by spraying or impregnation on concrete products such as bochado block, boundary block, raft block, vegetation raft block, and braille block Curing the coated photocatalyst coating composition in the temperature range of 18 ~ 150 ℃ to make a functional concrete product.

By coating the surface of the concrete with a photocatalyst coating composition comprising titanium dioxide coated with hydroxyapatite of the present invention, the concrete itself can maintain a clean surface for a long time and at the same time, By preventing the absorption, it is possible to prevent the cracking, strength reduction and whitening of concrete due to moisture.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the scope of the present invention is not limited thereto.

≪ Example 1 >

The photocatalyst coating of hydroxyapatite was used by forming a condition of the analogous liquid and mixing a substance subject to Ca ₁₀ (PO ₄ ) ₆ (0H) ₂ .

Analog solution used in the present invention is NaCl, NaHCO ₃ , KCl, K ₂ HPO _{4 ~} 3H ₂ O, MgCl ₂ ^~ 6H ₂ O, 1mol / dm ³ HCl, CaCl ₂ , Na ₂ SO ₄ , H ₂ NC (CH a ₂ OH) ₃ was prepared by dissolving in distilled water.

That is, after filling 800 ml of distilled water in a 1000 ml beaker, the beaker was placed in a thermostat and the temperature was adjusted to about 36.5 ° C., and then the reagent was first placed in a beaker in which the reagents were stirred with a magnetic stirrer in the order shown in Table 1 I put it in order, checking that it was completely melted. Finally, after adjusting the pH at 36.5 ° C with Tris-Buffer Solution {H ₂ NC (CH ₂ OH) ₃ } and 1N-HNO ₃ solution, the pH of the solution in the beaker is 7.25 at 36.5 ° C. The volumetric glass flask was transferred from to a distilled water filled with a total volume of 1000 ml, and then shaken well to prepare an analogous liquid.

After adding and dispersing 2.3 g of titanium dioxide to 1000 ml of the analogous solution, the hydroxyapatite was allowed to settle on the surface of titanium dioxide constantly while stirring for 1 hour, and then hydroxyapatite was stirred for 24 hours while the stirring was stopped. Grown. Then, heat was applied at 200-300 ° C. for 1 hour to obtain a slurry of an aqueous solution of titanium dioxide photocatalyst coated with more stable hydroxyapatite.

99.441% by weight of slurry of aqueous solution of hydroxyapatite-coated titanium dioxide photocatalyst prepared by the above method was mixed with 0.43% by weight of silicon hydroxide and 0.043% by weight of methanol, 0.043% by weight of Xanthan Gum, sorbic acid After adding 0.043% by weight of potassium to stir at high speed to prepare a photocatalyst coating composition comprising titanium dioxide coated with the hydroxyapatite of the present invention, the concrete interlocking block was spray-coated at 25 ° C., followed by 24 hours at 25 ° C. It was dried to prepare a concrete interlocking block coated with a photocatalyst coating composition.

<Example 2>

99.421 wt% of the slurry in the aqueous solution of the titanium dioxide photocatalyst coated with hydroxyapatite of Example 1 was mixed with 0.45 wt% of silicon hydroxide and 0.043 wt% of methanol, 0.043 wt% of Xanthan Gum, and sorbic acid while stirring at low speed. After adding 0.043% by weight of potassium to stir at high speed to prepare a photocatalyst coating composition comprising titanium dioxide coated with the hydroxyapatite of the present invention, the concrete interlocking block was spray-coated at 25 ° C., followed by 24 hours at 25 ° C. It was dried to prepare a concrete interlocking block coated with a photocatalyst coating composition.

<Example 3>

99.401% by weight of the slurry of the aqueous phase of the titanium dioxide photocatalyst coated with hydroxyapatite of Example 1 was mixed with 0.47% by weight of silicon hydroxide, while stirring at low speed, 0.043% by weight of methanol, 0.043% by weight of Xanthan Gum, sorbic acid After adding 0.043% by weight of potassium to stir at high speed to prepare a photocatalyst coating composition comprising titanium dioxide coated with the hydroxyapatite of the present invention, the concrete interlocking block was spray-coated at 25 ° C., followed by 24 hours at 25 ° C. It was dried to prepare a concrete interlocking block coated with a photocatalyst coating composition.

<Example 4>

99.381% by weight of the slurry in the aqueous solution of the titanium dioxide photocatalyst coated with the hydroxyapatite of Example 1 was mixed with 0.49% by weight of silicon hydroxide, while stirring at low speed, 0.043% by weight of methanol, 0.043% by weight of Xanthan Gum, and sorbic acid. After adding 0.043% by weight of potassium to stir at high speed to prepare a photocatalyst coating composition comprising titanium dioxide coated with the hydroxyapatite of the present invention, the concrete interlocking block was spray-coated at 25 ° C. and then 25 ° C. at 24 ° C. Drying was performed to prepare a concrete interlocking block coated with a photocatalyst coating composition.

Comparative Example 1

99.935% by weight of the slurry of the aqueous phase of the titanium dioxide photocatalyst coated with the hydroxyapatite of Example 1 was mixed with 0.05% by weight of silicon hydroxide, while stirring at low speed, 0.005% by weight of methanol, 0.005% by weight of Xanthan Gum, and sorbic acid. After adding 0.005% by weight of potassium to stir at high speed to prepare a photocatalyst coating composition comprising titanium dioxide coated with the hydroxyapatite of the present invention, the concrete interlocking block was spray-coated at 25 ° C., followed by 24 hours at 25 ° C. It was dried to prepare a concrete interlocking block coated with a photocatalyst coating composition.

Comparative Example 2

99.74 wt% of the slurry of the aqueous solution of the titanium dioxide photocatalyst coated with the hydroxyapatite of Example 1 was mixed with 0.2 wt% of silicon hydroxide, stirred at low speed, 0.02 wt% of methanol, 0.02 wt% of Xanthan Gum, and sorbic acid. After adding 0.02% by weight of potassium to stir at high speed to prepare a photocatalyst coating composition comprising titanium dioxide coated with the hydroxyapatite of the present invention, the concrete interlocking block was spray-coated at 25 ° C. and then 24 hours at 25 ° C. It was dried to prepare a concrete interlocking block coated with a photocatalyst coating composition.

&Lt; Comparative Example 3 &

99.42% by weight of the slurry of the aqueous solution of the titanium dioxide photocatalyst coated with the hydroxyapatite of Example 1 was mixed with 0.52% by weight of silicon hydroxide and stirred at a low speed of 0.02% by weight of methanol, 0.02% by weight of Xanthan Gum, and sorbic acid. After adding 0.02% by weight of potassium to stir at high speed to prepare a photocatalyst coating composition comprising titanium dioxide coated with the hydroxyapatite of the present invention, the concrete interlocking block was spray-coated at 25 ° C., followed by 24 hours at 25 ° C. It was dried to prepare a concrete interlocking block coated with a photocatalyst coating composition.

<Comparative Example 4>

99.14 wt% of the slurry in the aqueous solution of the titanium dioxide photocatalyst coated with hydroxyapatite of Example 1 was mixed with 0.8 wt% of silicon hydroxide, 0.02 wt% of methanol, 0.02 wt% of Xanthan Gum, and sorbic acid while stirring at low speed. After adding 0.02% by weight of potassium to stir at high speed to prepare a photocatalyst coating composition comprising titanium dioxide coated with the hydroxyapatite of the present invention, the concrete interlocking block was spray-coated at 25 ° C., followed by 24 hours at 25 ° C. It was dried to prepare a concrete interlocking block coated with a photocatalyst coating composition.

&Lt; Test Example 1 >

Photocatalytic Performance Evaluation

In order to evaluate the photocatalytic performance of the concrete interlocking blocks of Examples 1 to 4 and Comparative Examples 1 to 4, the photocatalytic performance evaluation test-gas bag B method proposed by the Korean Photocatalyst Association was performed.

The results are shown in Table 2.

As can be seen in Table 2, Example 1 (0.43% by weight of silica binder), Example 2 (0.45% by weight of silica binder), Example 3 when the content of the silica binder is in the range 0.43-0.49% by weight Silica binder 0.47 wt%) and Example 4 (0.49 wt% silica binder) showed that acetaldehyde decomposition efficiency was superior to 60% or more.

In addition, it was also found that the acetaldehyde decomposition efficiency was superior to 60% or more in Comparative Example 1 (0.05 wt% silica binder) and Comparative Example 2 (0.2 wt% silica binder) when the content of silica binder was less than 0.43 wt%. .

However, in Comparative Example 3 (0.52 wt% silica binder) and Comparative Example 4 (0.8 wt% silica binder), where the silica binder content was more than 0.49 wt%, the silica-condensed silica on the surface of the titanium dioxide photocatalyst As the functionalities were rapidly reduced by blocking, the acetaldehyde decomposition efficiency was low as 30% and 10%, respectively.

&Lt; Test Example 2 &

Water repellent performance evaluation

In order to evaluate the water-repellent performance of the concrete interlocking blocks of Examples 1 to 4 and Comparative Examples 1 to 4 were tested by applying the KS F 2609 method.

That is, after cutting so that the surface area of the upper surface of the concrete interlocking blocks of Examples 1 to 4 and Comparative Examples 1 to 4 to 100cm ² and sealing the side surface using a silicone sealing agent (sealing) and dried for more than 24 hours only Water was absorbed only to the upper surface of the concrete interlocking block, soaked in water of 1cm depth and the water repellency was measured by measuring the water repellency with time.

The results are shown in Table 3.

As can be seen in Table 3, Example 1 (0.43% by weight of silica binder), Example 2 (0.45% by weight of silica binder), Example 3 when the content of the silica binder is in the range 0.43-0.49% by weight. (0.47 wt% of silica binder) and Example 4 (0.49 wt% of silica binder) showed that the water absorption coefficient was less than 1000 and the water repellency was excellent.

In addition, in Comparative Example 3 (0.52 wt% silica binder) and Comparative Example 4 (0.8 wt% silica binder), wherein the silica binder content was more than 0.49 wt%, the water absorption coefficient was 0.49 wt%. It was confirmed that there is no significant difference compared with that of the addition of more silica binder was found to be meaningless.

However, in Comparative Example 1 (0.05 wt% silica binder) and Comparative Example 2 (0.2 wt% silica binder), where the silica binder content was less than 0.43 wt%, the water absorption coefficient was greatly increased to 1000 or more, so that the water repellency rapidly decreased. I could see that.

In summary, the results of the above Experimental Examples 1 and 2, First, Example 1 (silica binder 0.43% by weight), Example 2 (silica binder 0.45) when the content of silica binder is in the range of 0.43 ~ 0.49% by weight. % By weight), Example 3 (0.47% by weight of silica binder) and Example 4 (0.49% by weight of silica binder) showed that ① the acetaldehyde decomposition efficiency was more than 60% and the photocatalyst performance was excellent, and ② the water absorption coefficient was 1000. Water repellency was also excellent below. Therefore, it was confirmed that the photocatalytic performance and the water repellent performance were excellent within 0.43-0.49 wt% of the binder content of silica.

Secondly, in Comparative Example 1 (0.05 wt% silica binder) and Comparative Example 2 (0.2 wt% silica binder) having a silica binder content of less than 0.43% by weight, the photocatalytic performance was excellent, with the acetaldehyde decomposition efficiency of 60% or more. , ② The water absorption coefficient is 1750g / m ² h ^0.5 , 1010 g / m ² h ^0.5 was shown, while in Example 1 (0.43 wt% silica binder) the water absorption coefficient was 320 g / m ² h ^0.5 and in Example 2 (0.45 wt% silica binder) the water absorption coefficient was 140 g / m ^It was found that the water absorption coefficient was more than 1000 before and after the silica binder content of 0.43 wt% at ² h ^0.5 , indicating a significant difference in water repellency.

Ii) In Comparative Example 3 (0.52 wt% silica binder) and Comparative Example 4 (0.8 wt% silica binder) where the content of silica binder was more than 0.49 wt%, the acetaldehyde removal rate was 30% and 10%, respectively. In Example 3 (0.47% by weight of silica binder) and Example 4 (0.49% by weight of silica binder), both showed a significant difference in photocatalytic performance, with the content of 0.49% by weight of silica binder being around 70%. The water absorption coefficient was confirmed that there is no significant difference compared to the case where the content of the silica binder is 0.49% by weight, it can be seen that the addition of more silica binder is not meaningful.

Accordingly, the photocatalytic performance and the water repellency performance of the silica binder in the range of 0.43% to 0.49% by weight based on 0.43% by weight and 0.49% by weight of the silica binder, respectively It can be seen that there is a difference in effectiveness.

Claims (3)

Photocatalyst coating composition consisting of 0.43 to 4.3% by weight of titanium dioxide coated with hydroxyapatite, silica binder, 0.043 to 0.43% by weight of thickener, 0.043 to 0.43% by weight of dispersant, 0.043 to 0.43% by weight of preservative, and 93.92 to 99.1% by weight of water. To The silica binder may be silicon hydroxide (Si (OH) ₄ ) or general Si (OR) ₄ (R: C _n H _{2n + 1} , 1≤n≤10), the photocatalyst coating composition, characterized in that included in the range 0.43 ~ 0.49% by weight based on the total amount of the photocatalyst coating composition. The method of claim 1, The coverage of the hydroxy apatite on the titanium dioxide surface is 5 to 36%, the photocatalyst coating composition. The method of claim 1, The photocatalyst coating composition of claim 1, wherein the hydroxyapatite-coated titanium dioxide has an average particle diameter of 1 to 250 nm.