Cement-based photocatalytic material, preparation method and self-cleaning outer wall decorative panel based on the material

Abstract

The application discloses a cement-based photocatalytic material, a preparation method and a self-cleaning outer wall decorative plate based on the material. The photocatalytic material comprises Portland cement and a photocatalytic dispersion liquid. The photocatalytic dispersion liquid comprises surfactants, nano metal oxides, a modifier and deionized water in parts by weight. In the preparation, part of the surfactants, the nano metal oxides and the deionized water are mixed to prepare an A-component dispersion liquid, the modifier and the remaining surfactants are mixed to prepare a B-component dispersion liquid, then the B-component dispersion liquid is added dropwise into the A-component dispersion liquid to prepare the photocatalytic dispersion liquid, and finally the Portland cement and the photocatalytic dispersion liquid are uniformly mixed to prepare the cement-based photocatalytic material. The cement-based photocatalytic slurry can form a super-flat cement-based photocatalytic layer on the surface of the self-cleaning outer wall decorative plate, and the surface is free of pores, has good aesthetic appearance and strong hydrophobicity.

Description

Technical Field

[0001] This invention belongs to the field of self-cleaning exterior wall decorative panels, and particularly relates to a cement-based photocatalytic material and its preparation method, and a self-cleaning exterior wall decorative panel based on this material. Background Technology

[0002] In 1967, Japanese scholar Akira Fujishima discovered the photocatalytic effect of semiconductors. Later, researchers utilized this effect to prepare self-cleaning glass. Self-cleaning glass can clean itself and also degrade organic pollutants and oxidize pollutants such as NOx and SOx in the air. Cement concrete is the most widely used material; if concrete could possess photocatalytic and self-cleaning functions, it would be of great significance in reducing air pollution and preventing urban smog.

[0003] At the beginning of this century, scholars both domestically and internationally studied a series of photocatalytic concrete projects. Two existing technical approaches exist: one involves attaching a layer of photocatalyst to the aggregate surface to prepare exposed aggregate concrete, utilizing the photocatalyst on the aggregate surface for photocatalytic effects; the other involves incorporating the photocatalyst into the concrete matrix to prepare photocatalytic concrete. Both methods produce concrete with rough surfaces that trap dirt and grime, failing to achieve self-cleaning effects. Furthermore, the second method requires a large amount of water, has high porosity, and requires a large amount of photocatalyst, while only the surface portion exerts the photocatalytic effect, resulting in high costs, significant waste, and poor performance. Summary of the Invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a cement-based photocatalytic slurry and its preparation method. The cement-based photocatalytic slurry can form an ultra-flat cement-based photocatalytic layer with no pores and strong hydrophobicity on the surface of self-cleaning exterior wall decorative panels.

[0005] Technical solution: The cement-based photocatalytic material of the present invention comprises silicate cement and photocatalytic dispersion in a mass ratio of 45-55:1; wherein, the photocatalytic dispersion comprises, by weight, 4.5-7 parts of surfactant, 2-5 parts of nano-metal oxide, 40-50 parts of modifier and 25-40 parts of deionized water;

[0006] The surfactant includes at least one of sodium stearate, Span80, TMN-3 or TMN-10; the modifier is octyltriethoxysilane, dodecyltriethoxysilane or isobutyltriethoxysilane.

[0007] The cement-based photocatalytic material of this invention is prepared by compounding silicate cement with a photocatalytic dispersion, and combining surfactants, modifiers, and nano-metal oxides to obtain the photocatalytic dispersion. This effectively solves the problem of uneven air bubbles on the surface caused by incomplete adhesion to the template during casting when the cement-based photocatalytic material is mixed with a water-reducing agent and water to form a slurry. Specifically, this invention prepares a photocatalytic dispersion by combining surfactants, modifiers, and nano-metal oxides, and then mixes this dispersion with silicate cement. The cement hydration product, calcium silicate hydrate (CSH), forms an ultra-flat surface on the ultra-flat template. Simultaneously, the addition of surfactants and modifiers reduces the surface tension of the air bubbles generated in the slurry, causing the bubbles to burst. This ultimately forms a non-porous photocatalytic thin film layer on the ultra-flat template, improving the aesthetics of the final self-cleaning exterior wall panel. Furthermore, the addition of surfactants and modifiers improves the hydrophobic properties of the prepared self-cleaning exterior wall panel.

[0008] Furthermore, the nano-metal oxides used in this cement-based photocatalytic material include at least one of nano-TiO2, nano-Fe3O4, or nano-WO3.

[0009] The method for preparing the above-mentioned cement-based photocatalytic material according to the present invention includes the following steps:

[0010] (1) Mix 2.5-4.0 parts of surfactant, nano metal oxide and deionized water, heat and stir for 15-30 minutes to fully blend and obtain the dispersion of group A;

[0011] (2) Mix the modifier with the remaining surfactant, heat and stir for 8-12 minutes to obtain the dispersion of group B;

[0012] (3) Add the B group dispersion dropwise to the A group dispersion while stirring, and cool to room temperature to obtain the photocatalytic dispersion;

[0013] (4) The silicate cement is uniformly mixed with the above photocatalytic dispersion to obtain the cement-based photocatalytic material.

[0014] This invention employs a stepwise method to prepare photocatalytic materials. First, a dispersion is prepared using a portion of surfactant, nano-metal oxide, and deionized water. Then, a modifier is mixed with the remaining surfactant to prepare a dispersion. Finally, the two dispersions are mixed to obtain a photocatalytic dispersion. This allows the modifier and surfactant to spread evenly in the cement-based photocatalytic slurry, facilitating demolding (without the need for a release agent) and simultaneously breaking up any uneven bubbles generated in the slurry.

[0015] Furthermore, in steps (1) and (3) of the method for preparing cement-based photocatalytic materials, the stirring speed is 300-400 rpm.

[0016] This invention relates to a self-cleaning exterior wall decorative panel based on the above-mentioned cement-based photocatalytic material. The self-cleaning exterior wall decorative panel is prepared by the following steps:

[0017] (1) Prepare cement paste by mixing cement-based photocatalytic material with water, add 0.5-2.5% polycarboxylate superplasticizer by mass of cement-based photocatalytic material, and stir to obtain cement-based photocatalytic slurry;

[0018] (2) A layer of cement-based photocatalytic slurry is poured on the ultra-flat template, and then the blank material is placed on it. After curing, the self-cleaning exterior wall decoration board is obtained.

[0019] Furthermore, the blank used for the self-cleaning exterior wall decorative panel is mortar or self-compacting concrete, and the installation method is casting or pressing.

[0020] Furthermore, the thickness of the cement-based photocatalytic slurry used in the self-cleaning exterior wall decorative panels is 0.5-2mm.

[0021] Beneficial effects: Compared with the prior art, the significant advantages of the present invention are: the cement-based photocatalytic slurry can form an ultra-flat cement-based photocatalytic layer on the surface of self-cleaning exterior wall decorative panels, and the thickness of the cement-based photocatalytic layer is only 0.5-2mm, which greatly improves the photocatalyst efficiency and significantly reduces the cost;

[0022] Furthermore, the concrete exterior wall decoration material prepared in this way, as a hanging panel, curtain wall panel or decorative exterior wall brick, can exert its photocatalytic effect, reduce air pollutants and degrade organic pollutants, while its surface is non-porous, has good aesthetics and strong hydrophobicity. Attached Figure Description

[0023] Figure 1 This is a product image of the self-cleaning exterior wall decorative panel prepared according to Example 1 of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0025] It should be noted that the mortar or self-compacting concrete blank material used in this invention can be purchased directly from commercial sources. The thickness of the blank can be flexibly adjusted according to the actual application, and this invention does not impose specific limitations.

[0026] The ultra-flat template used in this invention can be an ultra-flat acrylic board, reinforced glass, or a smooth stainless steel template, or a standard template lined with a smooth hard plastic board.

[0027] Example 1

[0028] The composition of the cement-based photocatalytic material in Example 1 is shown in Table 1 below, and the composition of the photocatalytic dispersion is shown in Table 2 below.

[0029] Table 1. Components of cement-based photocatalytic materials in Example 1

[0030] Serial Number raw material Content / serving 1 Silicate cement 50 2 Photocatalytic dispersion 1

[0031] Table 2. Components of the photocatalytic dispersion in Example 1

[0032]

[0033]

[0034] The preparation method of the cement-based photocatalytic material in Example 1 includes the following steps:

[0035] (1) Mix 2.5 parts of sodium stearate, nano TiO2 and deionized water, heat and stir on a magnetic stirrer for 20 min at a stirring speed of 350 rpm, and then mix them thoroughly to obtain the dispersion of group A.

[0036] (2) Mix octyltriethoxysilane with the remaining 1.5 parts of sodium stearate, heat and stir in a sealed environment on a magnetic stirrer for 10 minutes to obtain the dispersion of group B;

[0037] (3) Add the B group dispersion to the A group dispersion by a peristaltic pump for 50 minutes, stirring while adding at a speed of 350 rpm. After adding, cool to room temperature to obtain the C group dispersion.

[0038] (4) The ordinary silicate cement and the dispersion of group C are mixed evenly to obtain the cement-based photocatalytic material.

[0039] The preparation method of the self-cleaning exterior wall decorative panel based on the above-mentioned cement-based photocatalytic material includes the following steps:

[0040] (1) Cement-based photocatalytic material is mixed with water to prepare cement paste, and polycarboxylate superplasticizer accounting for 1.5% of the mass of the cement-based photocatalytic material is added and stirred to obtain cement-based photocatalytic slurry;

[0041] (2) Pour a layer of cement-based photocatalytic slurry on the ultra-flat template, with a thickness of 0.5-2mm, completely covering but not piling up; pour wet plastic mortar or fine stone concrete into the mold and vibrate to compact it; or lay dry hard mortar or fine stone concrete into the mold and compact it; cure for 2-10 days until a smooth surface that can be seen through is formed, and then the self-cleaning exterior wall decoration board is obtained.

[0042] The decorative panels prepared in this embodiment are as follows: Figure 1 As shown, its surface is so smooth it reflects light like a mirror and has no pores.

[0043] Example 2

[0044] The composition of the cement-based photocatalytic material in Example 2 is shown in Table 3 below, and the composition of the photocatalytic dispersion is shown in Table 4 below.

[0045] Table 3. Components of cement-based photocatalytic materials in Example 2

[0046] Serial Number raw material Content / serving 1 Silicate cement 45 2 Photocatalytic dispersion 1

[0047] Table 4. Components of the photocatalytic dispersion in Example 2

[0048] Serial Number raw material Content / serving 1 TMN-3 4 2 <![CDATA[Nano Fe3O4]]> 2 3 Octyltriethoxysilane 40 4 Deionized water 40

[0049] The preparation method of the cement-based photocatalytic material in Example 2 includes the following steps:

[0050] (1) Mix 2.5 parts of TMN-3, nano Fe3O4 and deionized water, heat and stir on a magnetic stirrer for 25 min at a stirring speed of 300 rpm, and then mix them thoroughly to obtain the dispersion of group A.

[0051] (2) Mix octyltriethoxysilane with the remaining 1.5 parts of TMN-3, heat and stir in a sealed manner on a magnetic stirrer for 8 minutes to obtain the dispersion of group B;

[0052] (3) Add the B group dispersion to the A group dispersion by a peristaltic pump for 50 minutes, stirring while adding at a speed of 300 rpm. After adding, cool to room temperature to obtain the photocatalytic dispersion.

[0053] (4) The ordinary silicate cement and the photocatalytic dispersion are mixed evenly to obtain the cement-based photocatalytic material.

[0054] The preparation method of the self-cleaning exterior wall decorative panel based on the above-mentioned cement-based photocatalytic material includes the following steps:

[0055] (1) Cement-based photocatalytic material is mixed with water to prepare cement paste, and polycarboxylate superplasticizer accounting for 2% of the mass of the cement-based photocatalytic material is added and stirred to obtain cement-based photocatalytic slurry;

[0056] (2) Pour a layer of cement-based photocatalytic slurry on the ultra-flat template, with a thickness of 0.5-2mm, completely covering but not piling up; pour wet plastic mortar or fine stone concrete into the mold and vibrate to compact it; or lay dry hard mortar or fine stone concrete into the mold and compact it; cure for 2-10 days until a smooth surface that can be seen through is formed, and then the self-cleaning exterior wall decoration board is obtained.

[0057] Example 3

[0058] The composition of the cement-based photocatalytic material in Example 3 is shown in Table 5 below, and the composition of the photocatalytic dispersion is shown in Table 6 below.

[0059] Table 5. Components of cement-based photocatalytic materials in Example 3

[0060]

[0061]

[0062] Table 6. Components of the photocatalytic dispersion in Example 3

[0063]

[0064] The preparation method of the cement-based photocatalytic material in Example 3 includes the following steps:

[0065] (1) Mix 4 parts of composite surfactant, nano WO3 and deionized water, heat and stir on a magnetic stirrer for 15 min at a stirring speed of 400 rpm, and then mix them thoroughly to obtain the dispersion of group A.

[0066] (2) Mix dodecyltriethoxysilane with the remaining 2 parts of the composite surfactant, and heat and stir in a sealed environment on a magnetic stirrer for 12 minutes to obtain the dispersion of group B.

[0067] (3) Add the B group dispersion to the A group dispersion by a peristaltic pump for 50 minutes, stirring while adding at a speed of 400 rpm. After adding, cool to room temperature to obtain the photocatalytic dispersion.

[0068] (4) The ordinary silicate cement photocatalytic dispersion is uniformly mixed to obtain the cement-based photocatalytic material.

[0069] The preparation method of the self-cleaning exterior wall decorative panel based on the above-mentioned cement-based photocatalytic material includes the following steps:

[0070] (1) Cement-based photocatalytic material is mixed with water to prepare cement paste, and polycarboxylate superplasticizer accounting for 0.5% of the mass of the cement-based photocatalytic material is added and stirred to obtain cement-based photocatalytic slurry;

[0071] (2) Pour a layer of cement-based photocatalytic slurry on the ultra-flat template, with a thickness of 0.5-2mm, completely covering but not piling up; pour wet plastic mortar or fine stone concrete into the mold and vibrate to compact it; or lay dry hard mortar or fine stone concrete into the mold and compact it; cure for 2-10 days until a smooth surface that can be seen through is formed, and then the self-cleaning exterior wall decoration board is obtained.

[0072] Example 4

[0073] The composition of the cement-based photocatalytic material in Example 4 is shown in Table 7 below, and the composition of the photocatalytic dispersion is shown in Table 8 below.

[0074] Table 7. Components of cement-based photocatalytic materials in Example 4

[0075] Serial Number raw material Content / serving 1 Silicate cement 55 2 Photocatalytic dispersion 1

[0076] Table 8. Components of the photocatalytic dispersion in Example 4

[0077]

[0078] The preparation method of the cement-based photocatalytic material in Example 4 includes the following steps:

[0079] (1) Mix 4 parts of composite surfactant, compound nano metal oxide and deionized water, heat and stir on a magnetic stirrer for 30 min at a stirring speed of 400 rpm, and then fully mix them to obtain the dispersion of group A.

[0080] (2) Mix isobutyltriethoxysilane with the remaining 2 parts of composite surfactant, and heat and stir in a sealed environment on a magnetic stirrer for 10 min to obtain the dispersion of group B.

[0081] (3) Add the B group dispersion to the A group dispersion by a peristaltic pump for 50 minutes, stirring while adding at a speed of 400 rpm. After adding, cool to room temperature to obtain the photocatalytic dispersion.

[0082] (4) The ordinary silicate cement and the photocatalytic dispersion are mixed evenly to obtain the cement-based photocatalytic material.

[0083] The preparation method of the self-cleaning exterior wall decorative panel based on the above-mentioned cement-based photocatalytic material includes the following steps:

[0084] (1) Cement-based photocatalytic material is mixed with water to prepare cement paste, and polycarboxylate superplasticizer accounting for 2.5% of the mass of the cement-based photocatalytic material is added and stirred to obtain cement-based photocatalytic slurry;

[0085] (2) Pour a layer of cement-based photocatalytic slurry on the ultra-flat template, with a thickness of 0.5-2mm, completely covering but not piling up; pour wet plastic mortar or fine stone concrete into the mold and vibrate to compact it; or lay dry hard mortar or fine stone concrete into the mold and compact it; cure for 2-10 days until a smooth surface that can be seen through is formed, and then the self-cleaning exterior wall decoration board is obtained.

[0086] Comparative Example 1

[0087] (1) Mix 50 parts silicate cement, 2.5 parts nano TiO2, 0.75 parts water-reducing agent and appropriate amount of water to form a flowing slurry. Apply the slurry to the super-flat surface with a thickness of 0.5-2mm, completely covering it but not piling it up.

[0088] (2) Pour wet plastic mortar or fine stone concrete into the mold and vibrate to compact it; or lay dry hard mortar or fine stone concrete into the mold and compact it to form it.

[0089] (3) Curing in the mold for 2-10 days until a smooth, mirror-like surface is formed.

[0090] The self-cleaning exterior wall decorative panels prepared in Examples 1-4 and Comparative Example 1 were subjected to performance testing, and the results are shown in Table 9.

[0091] Table 9 Performance results of the self-cleaning exterior wall decorative panels prepared in Examples 1-4 and Comparative Example 1

[0092] Example Surface effect Water absorption ratio / % Penetration depth / mm Standard indicators Bright and non-porous ≤7.5％ ≥2.0mm Example 1 Bright and non-porous 5.50 5.2 Example 2 Bright and non-porous 6.98 4.4 Example 3 Bright and non-porous 6.59 4.7 Example 4 Bright and non-porous 6.35 4.2 Comparative Example 1 It has many air bubbles and is not smooth. 27.43 1.3

[0093] As can be seen from the table, the surface finish of each embodiment is glossy, effectively preventing the formation of air bubbles on the concrete surface and improving its workability; and the water absorption ratio is lower than the requirements in the JCT2235-2014 standard "Silica Protective Agents for Concrete". In other words, the self-cleaning exterior wall decorative panels prepared by this invention not only have a smooth surface but also a lower water absorption ratio and a significantly increased penetration depth.

[0094] Example 5

[0095] The composition of the cement-based photocatalytic material in Example 5 is shown in Table 10 below, and the composition of the photocatalytic dispersion is shown in Table 11 below.

[0096] Table 10. Components of cement-based photocatalytic materials in Example 5

[0097] Serial Number raw material Content / serving 1 Silicate cement 50 2 Photocatalytic dispersion 1

[0098] Table 8. Components of the photocatalytic dispersion in Example 4

[0099] Serial Number raw material Content / serving 1 Span80 7 2 <![CDATA[Nano-TiO2]]> 5 3 Isobutyltriethoxysilane 50 4 Deionized water 40

[0100] The preparation method of the cement-based photocatalytic material in Example 5 includes the following steps:

[0101] (1) Mix 3.5 parts of Span80, nano TiO2 and deionized water, heat and stir on a magnetic stirrer for 30 min at a stirring speed of 400 rpm to fully mix them and obtain the dispersion of group A.

[0102] (2) Mix isobutyltriethoxysilane with the remaining 3.5 parts of Span80, and heat and stir in a sealed manner on a magnetic stirrer for 10 minutes to obtain the dispersion of group B.

[0103] (3) Add the B group dispersion to the A group dispersion by a peristaltic pump for 50 minutes, stirring while adding at a speed of 400 rpm. After adding, cool to room temperature to obtain the photocatalytic dispersion.

[0104] (4) The ordinary silicate cement and the photocatalytic dispersion are mixed evenly to obtain the cement-based photocatalytic material.

[0105] The preparation method of the self-cleaning exterior wall decorative panel based on the above-mentioned cement-based photocatalytic material includes the following steps:

[0106] (1) Cement-based photocatalytic material is mixed with water to prepare cement paste, and polycarboxylate superplasticizer accounting for 1.5% of the mass of the cement-based photocatalytic material is added and stirred to obtain cement-based photocatalytic slurry;

[0107] (2) Pour a layer of cement-based photocatalytic slurry on the ultra-flat template, with a thickness of 0.5-2mm, completely covering but not piling up; pour wet plastic mortar or fine stone concrete into the mold and vibrate to compact it; or lay dry hard mortar or fine stone concrete into the mold and compact it; cure for 2-10 days until a smooth surface that can be seen through is formed, and then the self-cleaning exterior wall decoration board is obtained.

Claims

1. A cement-based photocatalytic material, characterized by: It is composed of silicate cement and photocatalytic dispersion in a mass ratio of 45-55:1; wherein, the photocatalytic dispersion is composed of 4-7 parts by weight of surfactant, 2-5 parts by weight of nano-metal oxide, 40-50 parts by weight of modifier and 25-40 parts by weight of deionized water; the nano-metal oxide includes at least one of nano-TiO2, nano-Fe3O4 or nano-WO3; The surfactant includes at least one of sodium stearate, Span80, TMN-3 or TMN-10; the modifier is octyltriethoxysilane, dodecyltriethoxysilane or isobutyltriethoxysilane. This cement-based photocatalytic material is prepared by the following steps: (1) Mix 2.5-4.0 parts of surfactant, nano metal oxide and deionized water, heat and stir for 15-30 min to fully blend and obtain the dispersion of group A; (2) Mix the modifier with the remaining surfactant, heat and stir for 8-12 min to obtain the dispersion of group B; (3) Add the B group dispersion dropwise to the A group dispersion while stirring, and cool to room temperature to obtain the photocatalytic dispersion; (4) The silicate cement is uniformly mixed with the above photocatalytic dispersion to obtain the cement-based photocatalytic material.

2. The cement-based photocatalytic material according to claim 1, characterized in that: In steps (1) and (3), the stirring speed is 300-400 rpm.

3. The self-cleaning exterior wall decorative panel based on the cement-based photocatalytic material according to claim 1, characterized in that This self-cleaning exterior wall panel is produced through the following steps: (1) Prepare cement paste by mixing cement-based photocatalytic material with water, add 0.5-2.5% polycarboxylate superplasticizer by mass of cement-based photocatalytic material, and stir to obtain cement-based photocatalytic slurry; (2) A layer of cement-based photocatalytic slurry is poured on the ultra-flat template, and then the blank material is placed on it. After curing, the self-cleaning exterior wall decorative board is obtained.

4. The self-cleaning exterior wall cladding panel according to claim 3, wherein: The blank is made of mortar or self-compacting concrete and is formed by casting or pressing.

5. The self-cleaning exterior wall cladding panel according to claim 3, wherein: The thickness of the cement-based photocatalytic slurry is 0.5-2 mm.

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