KR102286861B1 - Surface coating cement composition for air-purifying Type - Google Patents

Abstract

The present invention relates to an air purification type surface coating cement composition for surface coating of architectural/civil structures, and more particularly, to an air purification type surface coating cement composition for increasing the specific surface area of photocatalyst (TiO_2) particles exposed to the atmosphere by non-uniformly forming the surface of a coating surface using cement with low fitness processed through particle size modification, thereby maximizing air purification performance. The present invention provides 「an air purification type surface coating cement composition comprising modified cement that is usually processed with Portland cement, has a fineness of 2,200-3,000 cm^2/g, and contains 30 wt% or more of fine powder with a particle size of 44 ㎛ or more and titanium dioxide (TiO_2) powder added in an amount of 0.1 to 20 parts by weight relative to 100 parts by weight of the modified cement」.

Description

Air-purifying type surface coating cement composition {Surface coating cement composition for air-purifying Type}

The present invention relates to an air purification type surface coating cement composition for surface coating of architectural/civil structures, and more particularly, the surface of the coating surface is formed non-uniformly by using cement with low fineness processed through particle size modification. Thus, it relates to an air purification type surface coating cement composition formulated to maximize air purification performance by increasing the specific surface area of the photocatalyst (TiO _{2 ) particles exposed to the atmosphere.}

The interior and exterior of the building/civil engineering structure are finished by plastering with cement mortar or by applying cement paste after grinding the wall surface.

Plastering is a work of applying or spraying materials such as mortar, plaster, soil, etc. By smoothing marks or dents, it is used to facilitate subsequent paint work or final finishing material treatment.

The finished surface of the building/civil structure is the part exposed to light in contact with the external environment, and methods of constructing the finished surface in contact with the outside air with a finishing material applied with a photocatalyst have been continuously studied.

Photocatalyst is a catalyst that does not change before and after the reaction itself, but changes the reaction rate or improves the reaction by absorbing light. Be in the spotlight. In particular, the photocatalyst itself does not change even when exposed to light, so it can be used semi-permanently, has a higher oxidizing power than chlorine or ozone, so it has excellent sterilization power, and can decompose all organic substances into carbon dioxide and water. Accordingly, it has excellent abilities in air purification, antifouling function, hydrophilic function, water purification, deodorization, and antibacterial function.

Among them, the application of photocatalysts, which is receiving the highest expectations, is in the field of air purification, which not only decomposes various volatile organic compounds (VOCs, Volatile Organic Compounds) through photocatalytic reactions, but also removes nitrogen oxides (NOx) and sulfur oxides (SOx). It is also reported to show excellent effects. A representative material used as a double photocatalyst is titanium dioxide (TiO ₂ ). Titanium dioxide (TiO ₂ ) is abundant in resources, so it is inexpensive, and as a photocatalyst, it has excellent durability and abrasion resistance.

As described above, various studies are being conducted on the application of photocatalysts to construction materials, and research on a method for immobilizing a photocatalyst in a solid powder state to construction materials should be preceded.

The method of immobilizing the photocatalyst on the construction material can be divided into a method of substituting a part of cement with a photocatalyst, a method of infiltrating the photocatalyst into the surface of the finished surface using a surface penetrant, and a method of coating the photocatalyst on the surface of the finished surface.

Hereinafter, some prior art for finishing cement and construction materials using a photocatalyst will be introduced.

1. Registered Patent No.1960886 "Method for manufacturing high-strength gait block with fine dust reduction and air purification function"

Registered Patent No.1960886 relates to a method for manufacturing a high-strength porosity block having an air purification function by reducing fine dust in the atmosphere. It relates to a method for manufacturing a high-strength tolerance block having a fine dust reduction and air purification function, which has the effect of reducing fine dust and air purification by removing it.

Specifically, "a first step of preparing a base layer composition by mixing coarse aggregate, fine aggregate, cement, water and an admixture; After the base layer composition is put into a mold provided on the top of the vibrating lower plate, the vibrating upper plate is lowered into the mold, and the base layer composition is vibrated by the vibrating upper plate and the vibrating lower plate and press-molded to manufacture the base layer part. ; A third step of preparing a surface layer composition by mixing fine aggregate, cement, water and a photocatalyst material; wherein, in the third step, the fine aggregate, cement and photocatalyst material are dry mixed, and the photocatalytic material is TiO2, ZrO2, 50% by weight of fly ash is mixed with 50% by weight of one or two or more photocatalysts selected from the group consisting of V2O3, WO3, CuO, and SrTiO3, and the surface layer composition is subjected to pressure molding while vibrating by the vibrating upper plate and the vibrating lower plate. The fourth step of manufacturing; and the prepared surface layer part has a porosity of 6 to 10%, so that it is possible to maximize the photocatalytic properties by facilitating the movement of the photocatalytic material to the surface of the surface layer part during vibration and pressure It provides a method for manufacturing high-strength tolerance block with features of fine dust reduction and air purification functions.”

2. Registered Patent No. 0949945 "Road paving method using cement-based mortar"

Registered Patent No. 0949945 relates to a road paving method using a cement-based mortar. To explain this in more detail, a surface layer is applied to the top of the base layer composed of cement concrete, asphalt concrete, etc. It relates to a road pavement method using cement-based mortar, which is easy to construct and economical because it does not require the entire pavement to be made of functional concrete as various functions such as air purification function, insulation function, slip resistance function, and color road pavement are expressed.

Specifically, "Based on the step of constructing a base layer using cement concrete or asphalt concrete and 100 parts by weight of cement, 3 to 20 parts by weight of polymer, 50 to 400 parts by weight of fine aggregate having a particle size of 0.25 to 2 mm, and aluminum silicate as an insulating material. Construct the surface layer by laying cement-based mortar formulated with 5 to 20 parts by weight of fine powder, 30 to 100 parts by weight of water, 3 to 20 parts by weight of photocatalyst, 1 part by weight or less of thickener (more than 0 parts by weight), and 3 to 20 parts by weight of pigment. However, it provides a road paving method using a cement-based mortar, characterized in that it comprises the step of installing the surface layer to a thickness of 3 to 10 mm.”

3. Registered Patent No. 1728445 "Environment-friendly cosmetic additive with antibacterial and deodorizing function, plastering cement and mortar using the same"

Registered Patent No. 1728445 relates to an eco-friendly cosmetic additive having antibacterial and deodorizing functions, and plastering cement and mortar using the same. An eco-friendly cosmetic additive with antibacterial and deodorizing functions that can build an eco-friendly residential space by adsorbing and removing various harmful gases generated from cement as well as using it as an interior and exterior material for construction with antifungal, antibacterial and air purifying properties, It relates to cement and mortar for plastering using the same.

Specifically, "including sericite, activated carbon, loess, clay, gypsum, photocatalyst, pyrethroid-based insect repellent powder, zeolite and gelite, wherein the sericite is powdered after heat treatment within the range of 1200 to 1300 ° C., The photocatalyst is formed of a mixed powder in which titanium dioxide (TiO2), silicon dioxide (SiO2) and nano-silver powder are mixed, and as the pyrethroid insect repellent powder, bifenthrin is used, the sericite is 50 to 100 parts by weight, and the activated carbon is 5 to 5 parts by weight. 15 parts by weight, the ocher is 10 to 20 parts by weight, the white clay is 3 to 5 parts by weight, the gypsum is 60 to 100 parts by weight, the photocatalyst is 2 to 5 parts by weight, the bifenthrin is 0.01 to 0.02 parts by weight, the It provides an eco-friendly cosmetic additive having antibacterial and deodorizing functions, characterized in that the zeolite is prepared by mixing 10 to 20 parts by weight and the gel light is mixed in a weight ratio of 5 to 15 parts by weight.”

4. Registered Patent No. 1205491 "Non-fired cement permeable block with photocatalytic coating and manufacturing method thereof"

Registered Patent No. 1205491 relates to a non-fired cement permeable block provided with a photocatalytic coating, and more specifically, a photocatalyst is coated on the non-fired cement permeable block to provide a purifying function as well as improved substructure to improve water permeability. It relates to an improved, unfired cement permeable block provided with a photocatalytic coating and a method for manufacturing the same.

Specifically, it provides "a method of manufacturing a water permeable block, characterized in that the curing-dried upper surface of the water permeable block is coated with a photocatalyst to a thickness of 0.3 to 100 mm".

The above prior art provides various methods for immobilizing a photocatalyst to a construction material. Conventional methods for immobilizing photocatalysts have the following characteristics.

The method of using a photocatalyst by substituting a part of cement can distribute the photocatalyst evenly over the entire finishing layer, so there is little risk of performance degradation due to abrasion of the finishing layer. However, in the case of Prior Art Document 1, the photocatalyst is replaced with a part of cement to form the surface layer of the block, and the photocatalyst is mixed into the composition of the surface layer of the block to form the block, so the amount of photocatalyst is increased, and the amount of photocatalyst is increased. Since the photocatalytic reaction occurs only on the surface, the photocatalyst mixed inside cannot exhibit air purification performance, and thus economic efficiency and efficiency are lowered. Even in the case of the prior art document 3, the amount of the photocatalyst is increased and the photocatalyst mixed in the unseen surface has disadvantages in that the air purification performance is lowered.

The method of penetrating the photocatalyst into the concrete surface using a surface penetrant is a method of fixing the photocatalyst by penetrating it to the inside of the concrete or asphalt surface using a surface penetrating agent. There are advantages. However, there are problems in that it is difficult to penetrate the photocatalyst to an appropriate depth depending on the characteristics of the concrete structure or the penetrant, or it promotes deterioration of the concrete, thereby causing loss of the photocatalytic effect and damage to the concrete.

In the method of coating the photocatalyst on the concrete surface, the concrete is made into a double structure so that the inner side that is not exposed to the air is made of concrete without photocatalyst, and the photocatalyst is used on the surface exposed to the air and pollutants using an inorganic or organic adhesive. It is a method of fixing by coating the surface part. In particular, in the process of manufacturing secondary cement products such as blocks, a method of curing by attaching a mortar layer mixed with a photocatalyst to the surface of the product is generally used. is generally applied. This method was actively applied and tested on asphalt roads, and it was installed on some sections of Seoul inner road and Gyeongbu Expressway by spraying an aqueous solution mixed with a photocatalyst on the pavement. However, when the photocatalyst powder is mixed with an organic adhesive (acrylic, epoxy, etc.) and fixed, the organic adhesive is decomposed by the chemical reaction of the photocatalyst and the photocatalyst powder is gradually separated and lost, resulting in reduced durability, and inorganic adhesive (cement, etc.) In the case of mixing and fixing, the photocatalyst is buried in an inorganic adhesive that does not transmit light, so there is a problem in that the activity of the photocatalytic reaction is lowered. In the case of prior art documents 2 and 4, countermeasures to the above problems are not presented.

As described above, various techniques for imparting air purification performance to concrete of structures using a photocatalyst have been proposed, but research is mainly focused on a technique for adding a photocatalyst to concrete. The above technology usually presents a composition in which a photocatalyst is partially substituted in Portland cement-based cement mortar, its manufacturing method, and construction method. Basically, cement, mortar, and concrete are materials that do not transmit light. Most of the photocatalysts, except for the photocatalysts on the surface of the finishing material, are not exposed to light, so the air purification performance is deteriorated.

In order to overcome the performance degradation, a method of increasing the amount of photocatalyst is mainly used. In this case, the adhesion and tensile strength of the cement mortar decreases, cracks occur, and the manufacturing cost increases.

In order to solve the above problems, it is required to develop a technology for a cement composition and a construction method that can improve the workability and durability of the finished part while increasing the specific surface area of the photocatalyst in contact with the outside air.

1. Registered Patent No.1960886 "Method for manufacturing high-strength block diagram of fine dust reduction and air purification function", 2019. 03. 21. Announcement 2. Registered Patent No. 0949945 "Road paving method using cement-based mortar", 2010. 03. 30. Announcement 3. Registered Patent No. 1728445 "An eco-friendly cosmetic additive with antibacterial and deodorizing function, plastering cement and mortar using the same", 2017. 04. 24. Announcement 4. Registered Patent No. 1205491 "Non-fired cement permeable block with photocatalytic coating and manufacturing method thereof" 2012. 11. 27. Announcement

The present invention fixes a photocatalyst to the finished surface of a building/civil engineering structure, increases the specific surface area of photocatalyst particles exposed to the outside air, and is easy to construct on the surface of the existing structure as well as the plastering surface of the new structure, adhesion and An object of the present invention is to provide an air purification type surface coating cement composition capable of improving durability.

In order to solve the above problems, the present invention is "normally processed Portland cement, having a fineness of 2,200 ~ 3,000 cm / g, and containing 30 wt% or more of fine powder with a particle size of 44 μm or more, and 100 weight of the modified cement Provided is an air purifying surface coating cement composition comprising _{titanium dioxide (TiO 2} ) powder added in an amount of 0.1 to 20 parts by weight.

In addition, the present invention is an air purifying surface coating, characterized in that "a powdery thickener composed of either a cellulose-based or an amide-based thickener is further incorporated in an amount of 1.5 parts by weight or less (excluding 0 parts by weight) relative to 100 parts by weight of the modified cement. cement composition".

In addition, the present invention is "a powder resin consisting of any one of vinyl acetate-based, vinyl acetate ethylene-based, vinyl acetate vinyl versatate, and styrene-acrylic type, 0.05 to 3.0 parts by weight of the modified cement, compared to 100 parts by weight of the modified cement. An air purifying surface coating cement composition, characterized in that it is provided together.

In addition, the present invention provides "the _{air purification type surface coating cement composition, characterized in that the titanium dioxide (TiO 2} ) powder contains fine powder with a particle size of 20 μm or more not exceeding 20 wt %".

According to the present invention, the following effects can be expected.

1. Photocatalytic Portland cement particle size modified to the conditions set out in the claims (TiO ₂₎ powder and mixed by coating the surface of the structure, since the surface of the coated side to form the uneven photocatalyst is exposed to the outside air (TiO ₂₎ Air purification performance can be improved and material usage can be reduced by increasing the specific surface area of

2. As the powder thickener that increases viscosity is incorporated into the air purifying surface coating cement composition of the present invention, material separation stability is increased to prevent bleeding. It has the effect of reducing the initial plastic shrinkage cracking by increasing the water retention of the cement paste and improving the overall workability.

3. By mixing the powder resin into the air purification type surface coating cement composition of the present invention, the adhesion strength of the coated surface is improved.

4. The air purifying surface coating cement composition of the present invention in which modified cement, photocatalyst powder, thickener and powdered resin are mixed in powder form can be used immediately by pouring only water at the work site, thus greatly shortening the working time.

5. The air purifying surface coating cement composition of the present invention can be coated on the surface of existing structures as well as new structures by adding a thickener and powder resin that improve adhesion strength and workability.

6. The air purifying surface coating cement composition of the present invention is advantageous as a base surface when applying paint, etc. on top of the surface because the whiteness increases as the exposed specific surface area of the photocatalyst increases.

The present invention relates to "normally processed Portland cement, having a fineness of 2,200 to 3,000 cm2/g, containing 30 wt% or more of fine powder with a particle diameter of 44 μm or more, and 0.1 to 20 parts by weight compared to 100 parts by weight of the modified cement. Provided is an air-purifying surface coating cement composition comprising the added titanium dioxide (TiO _{2 ) powder.”}

Materials that can be used as materials for the photocatalyst include TiO ₂ , ZrO ₂ , V2O ₃ , WO ₃ , CuO, _{SrTiO 3 ,} ZnO etc exist. In the present invention, it can be used semi-permanently because it does not change itself even when exposed to light, has a higher oxidizing power than chlorine or ozone, so it has excellent sterilization power, can decompose all organic substances into carbon dioxide and water, and is inexpensive because it is abundant in resources, and photocatalyst Provided is an air-purifying surface coating cement composition in which _{titanium dioxide (TiO 2} ) is used as a photocatalyst, which has excellent durability and abrasion resistance and is a safe/non-toxic material that has no concern about secondary pollution even when discarded.

Titanium dioxide (TiO ₂ ) There are three crystalline forms of anatase, rutile, and brookite in the crystal structure.

In the present invention, any of the above crystal types may be applied, but among them, titanium dioxide (TiO ₂ ) having a crystal structure of an anatase type is preferably used as a photocatalyst. The anatase type is unstable to heat, and the octahedron is very badly twisted, so the symmetry is significantly lower than that of the rutile type orthorhombic system. The crystal structure is unstable and it exhibits excellent photocatalytic activity. In addition, the anatase type has high optical activity and has a higher band gap than the rutile type and the brookite type, so that electrons and holes recombine (electron-). The probability of hole recombination is very low, and the photocatalytic activity by strong oxidizing power is significantly superior to that of the rutile type and the brookite type. Therefore, when titanium dioxide (TiO ₂ ) having an anatase-type crystal structure is used as a photocatalyst, a better effect can be expressed with less material than other crystal-type titanium dioxide (TiO _{2 ).}

The fineness of the ready-made ordinary Portland cement is 3,400-3,800 cm2/g, and the Portland cement of the present invention processed through particle size modification has a fineness of 2,200-3,000 cm2/g, so the particle size-modified cement is usually Portland cement and quality control are markedly different. The processed Portland cement of the present invention has a lower fineness than a general normal Portland cement, so that the surface of the coated surface is formed non-uniformly.

_{Therefore, when the air purifying surface coating cement composition prepared by mixing titanium dioxide (TiO 2} ) powder in the cement modified to a fineness of 2,200~3,000cm2/g is coated on the surface of the structure, the coating surface is unevenly formed _{The titanium dioxide (TiO 2} ) powder uniformly dispersed on the coating surface can maximize the exposed area in contact with the outside air.

In addition, the present invention is an air purifying surface coating, characterized in that "a powdery thickener composed of either a cellulose-based or an amide-based thickener is further incorporated in an amount of 1.5 parts by weight or less (excluding 0 parts by weight) relative to 100 parts by weight of the modified cement. cement composition". When the above-mentioned key agent is added, material separation stability is increased to prevent bleeding, and the initial plastic shrinkage cracking is reduced by increasing the water retention of the cement paste, thereby improving overall workability.

The present invention is a surface coating cement composition that is widely coated on a wall surface by a spreading method or a spraying method, and a certain level of viscosity (plastic viscosity and yield value) and workability are required together in a paste state. Accordingly, the surface coating cement provided by the present invention may be configured by further incorporating a powdery thickener composed of either a cellulose-based or an amide-based thickener that increases viscosity. In order to secure construction performance, it is preferable that methylcellulose-based and polysaccharide-based components are the main components, and polysaccharides and starches are included as auxiliary components. The plastic viscosity may be adjusted according to the mixing ratio of the cellulose-based or amide-based mixture.

In addition, the present invention is "a powder resin consisting of any one of vinyl acetate-based, vinyl acetate ethylene-based, vinyl acetate vinyl versatate, and styrene-acrylic type, 0.05 to 3.0 parts by weight of the modified cement, compared to 100 parts by weight of the modified cement. An air purifying surface coating cement composition, characterized in that it is provided together.

By mixing the powder resin, the adhesion strength of the air-purifying surface coating cement composition is increased, so that the coating operation can be performed on the wall surface of the existing concrete structure. When the photocatalyst is fixed by the surface coating method by mixing the photocatalyst with the cement paste, as the adhesion is increased by mixing the powder resin, the titanium dioxide (TiO ₂ ) powder due to deterioration of the paste has an effect of preventing the falling off.

In addition, the titanium dioxide (TiO ₂ ) powder of the present invention is characterized in that the fine powder with a particle diameter of 20 μm or more is included so as not to exceed 20 wt%. The smaller the particle size of the titanium dioxide (TiO ₂ ) powder, the more the exposed area increases when the same weight is used. As the exposed area increases, the air purification performance of _{the titanium dioxide (TiO 2 ) powder increases.} However, the smaller the surface area of the particle diameter of fine powder particles per unit weight 20㎛, titanium dioxide (TiO ₂₎ powder, based on the weight of the whole particle size 20㎛ The higher the weight ratio of the fine powder is included more than the titanium dioxide (TiO ₂₎ the air purifying performance of the powder This is not fully expressed. Therefore, the titanium dioxide (TiO ₂ ) powder is preferably limited so that the content of the fine powder with a particle diameter of 20 μm or more does not exceed 20 wt%.

Hereinafter, the present invention will be described in detail along with specific experimental results.

1. Comparative experiment on photocatalyst particle exposure and air purification performance

_{[Table 1] below shows the experimental results comparing the exposure of titanium dioxide (TiO 2} ) particles and air purification performance by comparing the particle size modified cement according to the present invention (Example) and the existing Portland cement (Comparative Example).

The present invention is a particle size-modified of ordinary Portland cement, has a fineness of 2,200 to 3,000 cm2/g, and contains 30 wt% or more of fine powder with a particle size of 44 μm or less, and 0.1 to 20 parts by weight compared to 100 parts by weight of the modified cement. It relates to an air-purifying surface coating cement composition comprising _{titanium dioxide (TiO 2} ) powder added in parts by weight. It is classified as a comparative example that does not belong to the fineness and mixing ratio of the invention.

During the experiment, the _{weight ratio of titanium dioxide (TiO 2} ) powder and the water-cement ratio (W/C) were kept constant at 5 wt% and 50%, respectively.

[Table 1] below shows the test results in the case of using the existing Portland cement but having a fineness of 3,600 cm 2 / g (Comparative Example 1) and a case of 3,200 cm 2 / g of powder (Comparative Example 2). In addition, when the particle size modified cement was used, but the powder was 2,800 cm2/g (Example 1), the powder was 2,400 cm2/g (Example 2), and the powder was 2,000 cm2/g (Comparative Example 3). separated. Comparative Example 3 uses modified cement, but is not included in the claims of the present invention. In addition, the particle size characteristics of the cement were measured by the weight ratio of the fine powder remaining after passing through a 44㎛ (standard sieve #325) sieve. Therefore, it is confirmed that the powderiness and the weight ratio of the fine powder having a particle size of 44 μm or more are inversely proportional.

The whiteness (L) is a numerical value of the whiteness of the surface, measured using a colorimeter, and expressed as the L value of the Hunter Lab color space. The higher the L value, the higher the whiteness.

The surface roughness (Rz) is a value measured by confirming the degree of uniformity of the surface with an optical microscope using the difference in height of the surface. The higher the Rz value, the more heterogeneous the surface is, and the area exposed to air per unit area increases.

The removal rates of nitrogen monoxide (NO) and nitrogen oxides (NOx) were measured according to ISO 22197-1 (2016) test method for air purification performance of photocatalytic materials.

division portland cement Grain-modified cement Comparative Example 1 Comparative Example 2 Example 1 Example 2 Comparative Example 3 Cement fineness (cm ² /g) 3,600 3,200 2,800 2,400 2,000 Weight ratio of fine powder with a particle size of 44㎛ or more in cement (wt%) 8.9 17.1 32.1 52.5 58.7 adherence Good error Photocatalyst TiO ₂ Content (wt%) 5 Whiteness (L*) 78.1 79.2 83.4 90.0 92.4 Surface roughness (Rz) 25.4 25.0 35.2 41.2 43.5 NO removal rate (vol%) 6.4 6.6 9.4 12.1 12.3 NOx removal rate (vol%) 3.4 3.5 6.8 7.5 7.5 Portland Cement(3,600)
Ratio of air purification performance (%) 100.0 102.9 200.0 220.6 220.6

It can be seen that Comparative Examples 1 and 2 using conventional Portland cement have lower whiteness and surface roughness compared to Examples 1 and 2 and Comparative Example 3 using modified cement, and the lower the fineness of the cement, the lower the whiteness and surface It can be seen that the roughness increases. The increase in surface roughness means that the air exposure area per unit area increases, and the air purification performance can be maximized by increasing the air exposure area of _{the titanium dioxide (TiO 2 ) powder contained in cement. Addition to cement as a photocatalyst} The titanium dioxide (TiO ₂ ) powder has a high whiteness, so the whiteness of the plastering surface increases as the exposure degree of _{the titanium dioxide (TiO 2 ) powder increases.} Also, in general, when cement with a low fineness is used, the roughness of the surface of the plastering part increases, and as the roughness of the surface increases, the whiteness decreases due to non-uniform light reflection. It is confirmed that the whiteness increases as the roughness of the surface increases. Therefore, it can be confirmed that the exposure of _{titanium dioxide (TiO 2} ) powder is increased when the particle size-modified cement having a low fineness is used compared to the case of using the existing Portland cement.

In addition, as for the removal rates of nitrogen monoxide (NO) and nitrogen oxides (NOx), the particle size-modified cement shows more than twice the removal rate compared to the existing Portland cement. On the other hand, it can be seen that the particle size-modified cement with a fineness of 2,800 cm2/g shows twice the removal rate, and as the fineness of the cement decreases, the removal rate of nitrogen monoxide (NO) and nitrogen oxides (NOx) increases. On average, it is confirmed that the nitrogen monoxide (NO) and nitrogen oxides (NOx) removal rates of the modified cement according to the present invention are increased by about 2.2 times compared to the existing Portland cement.

In Comparative Example 3, it was confirmed that 58.7 wt% of fine powder having a particle diameter of 44 μm or more was included when the fineness of cement was 2,000 cm 2 /g, and the air purification performance was superior to that of general Portland cement, but it was confirmed that the adhesion was rapidly reduced. do. It is preferable to limit the fineness of the modified cement to the range of 2,200 to 3,000 cm2/g in order to express the air purifying performance within the range in which the adhesion is not reduced and the decrease in adhesion is confirmed from the fineness of less than 2,200 cm 2 /g.

[Reference 1]

The [Reference Fig. 1] is a photograph of the applied coating surface. The left side is cured by coating the existing Portland cement on the surface, and the right side is cured by coating the particle size modified cement on the surface. When observed with the naked eye, it can be seen that the left side has a smoother surface compared to the right side, and the right side has a rougher surface than the left side, but it can be confirmed that the whiteness is higher due to the high exposure of the _{titanium dioxide (TiO 2 ) powder.}

[Reference Figure 2]

[Reference Fig. 2] is a graph comparing the surface roughness (Rz) of the applied coating surface. The box plot in the upper left of the graph shows the range of Rz value of the particle size modified cement with a fineness of 2,400 cm2/g, and the box in the lower right The figure shows the range of Rz value of the existing Portland cement with a fineness of 3,600cm2/g, and it can be seen that the surface roughness (Rz) of the modified cement is significantly increased compared to the existing Portland cement.

of existing Portland cement.
coated surface of Portland Cement
Surface roughness 3D image of existing Portland cement.
Surface Roughness 3D Contour

of grain-modified cement
coated surface of grain-modified cement
Surface roughness 3D image of grain-modified cement
Surface Roughness 3D Contour

[Table 2] is a photograph of the surface of the applied coating surface analyzed with an optical microscope and digital analysis equipment. The upper side is a photograph of the coated surface using the existing Portland cement, and the lower side is a photograph of the coated surface using the particle size modified cement. As can be seen from the above photo, it can be seen that the surface coated using the particle size modified cement is more heterogeneously formed compared to the coated surface using the existing Portland cement, and the degree of surface roughness is increased. The 3D contour line of the surface roughness on the right connects the same points according to the height of the surface in order to intuitively compare the surface roughness. . Therefore, the modified cement increases the surface area of the applied coating surface, thereby increasing the air exposure area.

2. photocatalyst powder( TiO ₂ ) Comparative experiment on air purification performance by content

[Table 3] below shows the experimental results comparing the air purification performance according to the amount of _{titanium dioxide (TiO 2 ) powder added to the particle size modified cement.}

[Table 3] below shows the case of using the existing Portland cement, but having a fineness of 3,600cm2/g and _{adding 5 parts by weight of titanium dioxide (TiO 2} ) powder (Comparative Example 4) and a particle size modified cement with a fineness of 2,400cm2/g However, when 0.1 parts by weight of titanium dioxide (TiO ₂ ) powder is added (Example 3), _{when 1 part by weight of titanium dioxide (TiO 2} ) powder is added (Example 4), titanium dioxide (TiO ₂ ) powder When 5 parts by weight of was added (Example 5) and _{when 10 parts by weight of titanium dioxide (TiO 2} ) powder was added (Example 6), _{when 20 parts by weight of titanium dioxide (TiO 2} ) powder was added (Example) 7). Parts by weight of the titanium dioxide (TiO ₂ ) powder are parts by weight added based on 100 parts by weight of each cement.

In the above experiment, the cement paste of the experimental example was maintained at a constant water-cement ratio (W/C) of 50%, and applied to the surface of a concrete test plate (acrylic plate surface) of the same shape and size to KS L ISO 22197-1 Fine Ceramics - The experiment was conducted based on the method of measuring the air purification performance of the semiconducting photocatalyst material.

division Portland
cement
(Powder degree 3,600cm ² /g) Grain size modified cement (powder 2,400cm ² /g) Comparative Example 4 Example 3 Example 4 Example 5 Example 6 Example 7 adherence Good relatively good Photocatalyst TiO ₂ Content (parts by weight) 5 0.1 One 5 10 20 Whiteness (L*) 78.1 80.1 80.2 90.0 94.5 95.4 NO removal rate (vol%) 6.4 0.2 2.0 12.1 30.2 45.2 NOx removal rate (vol%) 3.4 0.1 1.0 7.5 17.2 26.0 Portland Cement(3,600)
Ratio of air purification performance (%) 100.0 2.94 29.4 220.6 505.9 764.7

Although there is a difference in the amount of titanium dioxide (TiO ₂ ) added, when 0.1 parts by weight is added, a significant level of air purification performance (about 1.5 times the performance of normal Portland cement) is expressed, and more specifically, titanium dioxide (TiO) ₂ ) When 0.1 parts by weight of powder is added, the NOx removal rate is 0.2 vol%, which can be measured as clearly photoactive reaction occurs. In addition, as in Example 7, _{when 20 parts by weight of titanium dioxide (TiO 2} ) powder is added, the state of the finished surface is good, but when it is added in excess of 20 parts by weight, microcracks estimated as drying shrinkage occur. It was confirmed that when the titanium dioxide (TiO ₂ ) powder is added in excess of 20 parts by weight, it was confirmed that there is a risk of lowering the durability. When the titanium dioxide (TiO ₂ ) powder is added in excess of 20 parts by weight, the air purification performance is increased compared to other examples, but it is confirmed that the occurrence of microcracks increases and the durability decreases. If the adhesive force is reduced, the cement paste may be separated from the coating surface, causing cracks, and surface peeling and peeling may occur, resulting in a decrease in the strength of the coating surface. _{Therefore, it is preferable to limit the addition ratio of titanium dioxide (TiO 2} ) powder to the particle size-modified cement in the range of 0.1 to 20 parts by weight relative to 100 parts by weight of the cement.

In addition, in the table above, Comparative Example 4 was added for comparison with the existing Portland cement, and when _{the addition ratio of the titanium dioxide (TiO 2} ) powder of Comparative Example 4 was matched to 1 part by weight as in Example 3, the air purification performance ratio was It is expected to be 20%, which is 1/5 level. It can be seen that Example 3 has an air purification performance of about 30%, which is 29.4%, which is 1.5 times higher than that of the existing Portland cement, thereby exhibiting a significant level of air purification performance. _{Therefore, when the particle size modified cement is used, it is confirmed that the amount of titanium dioxide (TiO 2} ) powder can be reduced even with a small amount of titanium dioxide (TiO 2 ) powder compared to the existing Portland cement, and thus the amount of material used can be reduced.

3. thickener in the mixing ratio Construction performance comparison experiment

Cement for coating to spread widely on the wall surface requires a certain level of viscosity and workability in the paste state.

[Table 4] below is a summary of plastering properties, trowel finish, and surface dryness when a thickener is added to the particle size-modified cement to which a photocatalyst is added to secure construction performance.

The thickener according to the present invention is composed of either a cellulose-based or an amide-based thickener, and the thickener used for the experiment below contains 60 to 90 wt% of methylcellulose and polysaccharide as main components, and 5 to 20 wt% of polysaccharides and starches % mixtures can be used. The thickener was mixed with the cement of each of Comparative Examples and Examples to evaluate the construction performance according to the thickener addition ratio. During the experiment, the water-cement ratio (W/C) was kept constant at 50%, the surface coating cement with the thickener added to the concrete wall was spread thinly, and the construction performance was evaluated at this time.

For the constructability evaluation, important work performance factors (keywords) were selected for surface coating work, and the plastering properties, trowel finish, and surface roughness were selected and evaluated. In this case, it was judged whether the application could be performed smoothly without any resistance to the wrist during the application, and evaluation scores were given based on the ease of the application. For the trowel finish, the degree of occurrence of pores or scratches on the surface of the trowel was evaluated when the cement paste was applied, and evaluation scores were given by visually observing the remaining paste on the trowel. For surface dryness, evaluation scores were given by visually observing whether or not surface dryness occurred when the plastering work was completed. If the surface dryness occurs, additional repair work is required, resulting in poor workability. The work performance factors were given evaluation scores as very bad (1), bad (2), average (3), good (4), and very good (5). The experiment was performed directly on the concrete wall as shown in [Reference Fig. 3] below, and the applied surface of each experimental group was observed and compared as shown in [Reference Fig. 4].

[Reference 3]

[Reference 4]

division W/B (%) thickener
(parts by weight) Evaluation items cosmetic cleanliness trowel finish surface roughness Comparative Example 5 OPC-0 50 - 2 3 2 Comparative Example 6 development-0 50 - One 3 2 Example 8 Development - 0.3 50 0.3 4 4 4 Example 9 Development - 0.5 50 0.5 5 5 5 Example 10 Development - 1.5 50 1.5 3 4 5 Comparative Example 7 Development-3.0 50 3.0 0 One 5

[Table 4] shows that the conventional ordinary Portland cement was used, but a thickener was not added (Comparative Example 5), a particle size-modified cement with a photocatalyst was used, but a thickener was not added (Comparative Example 6), When 0.3 parts by weight of the thickener is incorporated (Example 8), when 0.5 parts by weight of the thickener is mixed (Example 9), when 1.5 parts by weight of the thickener is mixed (Example 10), and when 3.0 parts by weight of the thickener is incorporated (Comparative Example 7). The units of Comparative Examples and Examples are expressed in parts by weight relative to 100 parts by weight of each cement. When the thickener is added, the viscosity of the cement paste increases, and the workability is highest at 0.5 parts by weight, and when the thickener exceeds 1.5 parts by weight, it is confirmed that the workability decreases due to the increase in viscosity. In addition, as the thickener is added, the effect of preventing the occurrence of surface dryness also increases proportionally. As in Comparative Example 7, when 3.0 parts by weight of a thickener is added, it can be seen that the workability is lowered to such an extent that it is difficult to proceed with the plastering operation with 0 plastering. Therefore, when the thickener is added in excess of 1.5 parts by weight, the occurrence of surface dryness is suppressed, but the plastering properties and trowel finish are lowered, resulting in poor workability. It is preferable to further incorporate 1.5 parts by weight or less (excluding 0 parts by weight) compared to 100 parts by weight of the modified cement.

4. powdered resin in the mixing ratio Adhesive strength comparison test

The air purifying surface coating cement composition according to the present invention may add a powder resin to prevent deterioration of air purification performance due to separation of the _{added titanium dioxide (TiO 2 ) powder and to reinforce the durability of the coating part.} The powder resin is composed of any one of vinyl acetate, vinyl acetate ethylene, vinyl acetate, vinyl versatate, and styrene-acrylic, and has an effect of increasing adhesion.

When powdered resin is added, as the adhesion strength is increased, the photocatalyst particles are firmly fixed to the coating surface to be constructed, and the deterioration of the surface is prevented, and cracks caused by shrinkage are suppressed. In addition, the watertightness of the coating surface for construction increases, preventing the penetration of chloride or moisture in environments that are directly affected by external air such as roads, outdoors, beaches, and construction sites, and has strong frost resistance to prevent denaturation or damage of photocatalyst particles. play a role

[Table 6] below shows the air purification type surface coating cement paste on the upper surface of the 0×30×5mm (width×length×thickness) block using an iron trowel to flatten the top surface to a thickness of 2mm, and then the age of 14 days The experimental results of measuring the adhesion strength at this elapsed point are shown.

As shown in [Reference Fig. 5] and [Table 5] below, the measurement experiment of the adhesion strength was performed in accordance with KS F 4716 (cement-based plastering material) on the upper surface of the sample application surface with an upper tension jig (40 × 40 mm, horizontal × lengthwise, steel) was adhered using an adhesive, and a tensile force was applied in a direction perpendicular to the sample surface to obtain the maximum tensile load.

[Reference 5]

Adhesive strength Sample cutting and attachment Tester (Measuring Instrument, Jig, Connector) Adhesive strength measurement

division constituent material Adhesive strength
(MPa) cement
(wt%) TiO ₂
(wt%) thickener
(Additional parts compared to cement composition, parts by weight) powdered resin
(Additional parts compared to cement composition, parts by weight) comparative example Plain Ordinary Portland Cement
95 5 0.5 - 0.10 Example 11 VA-0.05 particle size modified cement
95 5 0.5 0.05 0.17 Example 12 VA-0.5 5 0.5 0.5 0.25 Example 13 VA-1.0 5 0.5 1.0 0.28 Example 14 VA-2.0 5 0.5 2.0 0.51 Example 15 VA-3.0 5 0.5 3.0 0.70

* The Table 6 Cement 95wt%, titanium dioxide (TiO ₂₎ the weight ratio of powder 5wt% in the experiment of the cement is less than 100 parts by weight compared to the titanium dioxide (TiO ₂₎ powder 5.26 is converted parts by weight charge of the scope of the present invention. The [Table 6] shows that the ratio of the particle size-modified cement of Comparative Examples and Examples is 95 wt%, the ratio of titanium dioxide (TiO ₂ ) powder is 5 wt%, and the ratio of the thickener is 0.5 parts by weight relative to 100 parts by weight of the cement composition. , and the powder resin was tested while adjusting the mixing weight part relative to 100 parts by weight of the cement composition. A polymer powder resin (vinyl acetylene) was used as the powder resin at this time.

In [Table 6], it can be seen that the adhesion strength increases proportionally with the increase in the amount of powdered resin added. The minimum value of the powder resin addition ratio, which significantly increases the adhesion strength, is 0.05 parts by weight, and when the addition ratio of the powder resin exceeds 3.0 parts by weight, the durability of the coated surface is deteriorated. When the addition ratio of the powdered resin exceeds 3.0 parts by weight, it is confirmed that the mixability of the cement paste is lowered and durability is lowered. Therefore, it is preferable to limit the addition ratio of the powdered resin to the particle size-modified cement in the range of 0.05 to 3.0 parts by weight based on 100 parts by weight of the cement composition.

The titanium dioxide (TiO ₂ ) powder of the present invention is preferably included so that the fine powder with a particle size of 20 μm or more does not exceed 20 wt%. The smaller the particle size of the titanium dioxide powder (the larger the degree of powder), the greater the exposure area based on the same weight. Therefore, as the inclusion ratio of the fine powder having a particle size of 20 μm or more increases, the exposed area of the titanium dioxide (TiO ₂ ) powder decreases.

Therefore, it is preferable to include fine powder having a particle size of 20 μm or more so as not to exceed 20 wt % by weight to express the optimal air purification performance.

As described above, the air purifying surface coating cement composition according to the present invention is processed through particle size modification, and titanium dioxide (TiO ₂ ) powder, which is a photocatalyst, is added to cement having a low fineness to expose the titanium dioxide (TiO ₂ ) powder to the atmosphere. It improves air purification performance by increasing the area, and by incorporating a thickener that increases viscosity, it has the effect of securing water retention and preventing bleeding and improving workability. . Therefore, the present invention provides a composition that can prevent separation of the photocatalyst and increase the strength of the coated surface while increasing the performance of the photocatalyst. Compared to the materials applied to this method, the air purification performance is excellent and the existing shortcomings can be supplemented. This provides a fixing method differentiated from the existing methods of fixing photocatalysts to construction materials. Table 5 below compares the strengths and weaknesses of the existing methods for fixing the construction material to the photocatalyst and the composition according to the present invention.

division substitution method Penetration method coating method the present invention Fixing method Part of cement is replaced with photocatalyst Penetrates the photocatalyst into the finished surface by mixing the surface penetrant Coating on the surface using an inorganic or organic adhesive Coating on the surface by mixing photocatalyst with particle size modification cement Advantages Able to distribute photocatalyst evenly
Low abrasion of the finish layer Increase of photocatalytic reaction
Reduction of risk due to wear ●Simple construction method
●Affordable price ●Simple construction method
●Material reduction
Increase the efficiency of photocatalyst
Prevention of damage due to deterioration of paste by adding powdered resin disadvantage Decreased efficiency of photocatalytic reaction
Increase in photocatalyst usage
●Increase in cost Difficult to penetrate photocatalyst
Fear of damage to the coating surface due to accelerated deterioration of the paste The organic adhesive is decomposed by the chemical reaction of the photocatalyst.
When inorganic adhesives are used, photocatalytic activity decreases

As shown in [Table 7], the present invention is partially similar to the coating method or the substitution method, but by adding a thickener and powder resin to the particle size modified cement, the disadvantages of the coating method or the substitution method are supplemented, and the performance of the photocatalyst while saving materials can be efficiently increased.

The photocatalyst fixing methods are in the process of research on technological development while repeating improvements in composition and construction method, respectively. The overcatalyst fixing method using the air-purifying surface coating cement composition in the present invention is a method in which a part of cement is replaced and coated on the surface, and is partially similar to the replacement method and the coating method, but is surface coated using cement having a low fineness It is differentiated from the existing methods in a way that the roughness of the surface increases and thus the reactivity of the photocatalyst is improved. Even if it is thinly coated on the coated surface, high air purification performance can be expressed, and it has excellent adhesion and strength so that it can faithfully perform the function as a finishing material for the structure. there is. Since the cement having different fineness has different effects and construction methods from other fixing methods, the photocatalytic fixing method using the composition of the present invention may be called a 'cement coating method'. [Reference Figure 6] below schematically shows the technological development direction of the photocatalyst fixing method according to the present invention, which can be referred to as the conventional photocatalyst fixing method and the cement coating method with reference to the above. As can be seen from the reference diagram below, there is a big difference between the conventional photocatalyst fixing method and the cement coating method according to the present invention in the method of fixing the photocatalyst, so each method cannot be technically substituted or substituted for each other, and technological development has been made independently. will be lost

[Reference Figure 6]

Therefore, the air purification type surface coating cement composition is preferably coated on the wall to be constructed to a thickness of 1 to 5 mm. Since the photocatalytic reaction occurs only on the surface in contact with the outside air, the photocatalyst mixed inside through which light is not transmitted is inefficient because the activity of the photocatalytic reaction is lowered. Therefore, when the surface of the wall to be constructed is coated with a thickness of 1 to 5 mm, it is economical and efficient because the reaction area of the photocatalyst is maximized while reducing the amount of photocatalyst mixed in.

The optimal construction method for coating the air purifying surface coating cement composition on the surface of the wall to be constructed is as follows.

(a) Modified cement, which is usually processed with Portland cement, has a fineness of 2,200~3,000cm2/g, and contains 30wt% or more of fine powder with a particle size of 44㎛ or more; and 0.1 to 20 parts by weight of the modified cement relative to 100 parts by weight of titanium dioxide (TiO ₂ ) powder; Preparing an air-purifying surface coating cement composition comprising a;

(b) preparing a surface coating material in which water is mixed with the air purification type surface coating cement composition;

(c) applying the surface coating material to the wall to be constructed to create a plastered surface;

The air purification type surface coating cement composition is prepared through step (a). It can also be provided in the form of a powder that is mixed on-site or pre-formulated at the factory. A paste-type surface coating material is prepared by mixing water with the powder-type air-purifying surface coating cement composition. Since the surface coating material is applied by a spraying method using a trowel or a spraying method using a spraying mechanism, the amount of water mixed in order to secure workability (viscosity, fluidity) can be adjusted.

In the application method of step (c), the spreading method applies a surface coating material mixed with water to the air purification type surface coating cement composition, but the spraying method may use a surface coating material further mixed with sand in addition to water. In the spraying method, the spraying mechanism mainly uses a spray gun, and the spray gun sprays the cement paste mixed with water in the form of a mist by the power of compressed air to coat the wall surface to be constructed. When spraying with a spray gun, the coating surface is formed as a thin film, so spraying is performed several times to form a coating surface with a thickness of 1 to 5 mm. The spraying method can further increase the amount of water compared to the spreading method using a trowel to secure fluidity. In case of spraying with cement paste only, the cement paste coated on the wall to be constructed may flow down due to gravity or the coating surface may sag. Therefore, in the spraying method, sand is mixed with the cement paste to increase the strength of the coating surface, thereby preventing sagging or dripping due to gravity.

In addition, the sand has a particle size distribution with a particle diameter of 0.075 to 4.5 mm and is characterized in that 100 to 800 parts by weight of the air purifying surface coating cement composition is mixed with 100 parts by weight compared to 100 parts by weight of the air purifying surface coating cement composition. Sand mixed to increase the amount of sand mixed in at least 100 parts by weight relative to 100 parts by weight of the surface coating cement composition can prevent dripping or sagging. There is a possibility that the coating surface may be damaged due to the increased weight. Therefore, it is preferable that 100 to 800 parts by weight of sand to be incorporated into the air purifying surface coating cement composition is mixed with respect to 100 parts by weight of the surface coating cement composition.

If the particle size is less than 0.075mm in the particle size distribution range of the sand, the unit quantity for securing workability increases and the durability deteriorates. There are problems in that the exposure of the photocatalyst is lowered, the durability of the coating surface is lowered, and the nozzle of the spray gun is blocked, so that the spray is not performed smoothly. Accordingly, the sand preferably has a particle size distribution of 0.075 to 4.5 mm in diameter.

In addition, in step (c), it is possible to create a plastered surface with a thickness of 1 to 5 mm. Since the photocatalytic reaction occurs only on the surface of the coating surface, when the coating surface is thick, the photocatalytic powder fixed to the inner side of the coated surface through which light is not transmitted is inefficient because the photocatalytic reaction does not occur. Therefore, it is preferable to limit the thickness of the coating surface to a thickness of 1 to 5 mm, which is an optimal thickness for securing coating strength and efficiently generating a photocatalytic reaction.

As described above, the plaster surface is created with a thickness of 1 to 5 mm, so that it can be applied to new buildings as well as existing buildings for which finishing materials work has been completed. If additional coating work is carried out in a building where the finishing material construction has been completed, there is a possibility that the finished surface may fall off or peel off due to an additional load applied by the coating material. However, when a beautiful scene is created by the construction method according to the present invention, the burden on the material load can be reduced, and the ratio of the photocatalyst powder buried therein can be lowered to increase the utilization of the photocatalyst and reduce the amount of material used.

The air purifying surface coating cement composition of step (a) is characterized in that 1.5 parts by weight or less (excluding 0 parts by weight) is further incorporated relative to 100 parts by weight of the modified cement. It provides an air purification type surface coating material plastering method. The composition ratio of the air purifying surface coating cement composition is the same as described above.

The air-purifying surface coating cement composition of step (a) contains a powder resin composed of any one of vinyl acetate-based, vinyl acetate ethylene-based, vinyl acetate vinyl versatate, and styrene-acrylic based 0.05 to 100 parts by weight of the modified cement. It provides an air purifying surface coating material plastering method, characterized in that 3.0 parts by weight is further incorporated. The composition ratio of the air purifying surface coating cement composition is the same as described above.

The titanium dioxide (TiO ₂ ) powder of step (a) provides an air purifying surface coating material plastering method, characterized in that the fine powder with a particle size of 20 μm or more does not exceed 20 wt %. The composition ratio of the air purifying surface coating cement composition is the same as described above.

Step (b) is a step of preparing a cement paste by mixing water with the air-purifying surface coating cement composition. Modified cement, photocatalyst powder, thickener, and powder resin are blended in an appropriate ratio within the provided ratio of the present invention. (powder composition). Because it can be used simply by mixing and mixing only water at the work site, the working time is greatly reduced. In addition, as described above, when applying by spraying method, it may be manufactured in the form of a mortar in which more sand is added.

Step (c) is a step of applying the surface coating material to the wall to be constructed to create a plastered surface. Since the thickness of the plastered surface is formed thin, after performing step (b), (b-1) It may further include the step of planarizing treatment. By removing the irregularities of the concrete wall surface and smoothing the bubble marks or dent marks, the follow-up work can be done smoothly.

At this time, the titanium dioxide (TiO ₂ ) powder is a white powder and does not significantly affect the color expression of the coated surface. The coating surface formed thinly with a thickness of 1 to 5 mm _{increases the specific surface area of the titanium dioxide (TiO 2} ) powder to improve reactivity. Accordingly, the contaminated air hitting the coating surface _{is adsorbed to the titanium dioxide (TiO 2} ) exposed on the surface of the coating surface, and nitrogen oxide (NOx) contained in the contaminated air as it receives light in this state and It chemically decomposes sulfur oxides (SOx) to release carbon dioxide and water.

Although the present invention has been described in relation to the preferred embodiment as mentioned above, various modifications and variations are possible without departing from the gist of the present invention, and can be used in various fields. Accordingly, the claims of the present invention include modifications and variations that fall within the true scope of the preceding invention.

Claims (4)

A cement composition for use as a surface coating material for coating construction on the finished surface of building/civil structures,
Modified cement that is usually processed by Portland cement, has a fineness of 2,200~3,000cm2/g, and contains 30wt% or more of fine powder with a particle size of 44㎛ or more; and
_{0.1-20 parts by weight of titanium dioxide (TiO 2} ) powder added relative to 100 parts by weight of the modified cement; An air purifying surface coating cement composition formulated to increase the specific surface area of _{titanium dioxide (TiO 2} ) particles exposed to the atmosphere by non-uniformly forming the surface of the coating surface, including
In claim 1,
A powdery thickener composed of any one of cellulose-based or amide-based thickeners,
An air purifying surface coating cement composition, characterized in that it is further incorporated in an amount of 1.5 parts by weight or less (excluding 0 parts by weight) relative to 100 parts by weight of the modified cement.
In claim 1,
A powder resin composed of any one of vinyl acetate, vinyl acetate ethylene, vinyl acetate, vinyl versatate, and styrene-acrylic,
An air purifying surface coating cement composition, characterized in that 0.05 to 3.0 parts by weight is further mixed with respect to 100 parts by weight of the modified cement.
According to any one of claims 1 to 3,
The titanium dioxide (TiO ₂ ) powder,
An air purifying surface coating cement composition comprising fine powder having a particle size of 20 μm or more not to exceed 20 wt %.