Geopolymer water-resistant coating and method for preparing the same

Abstract

The application belongs to the technical field of coating preparation, and discloses a geopolymer water-resistant coating and a preparation method thereof.The coating is prepared from the following raw materials in parts by weight: 100 parts of potassium silicate aqueous solution, 10-80 parts of filler, 0-20 parts of color paste, 0.5-2 parts of additive, 5-20 parts of organic silicon modified waterborne polyurethane emulsion, and 10-30 parts of water;the preparation process is as follows: water is mixed with the filler, the color paste, and the additive to form a colloidal mixture, then the colloidal mixture is added into the organic silicon modified waterborne polyurethane emulsion under stirring, and after uniform mixing, the potassium silicate aqueous solution is added, and the geopolymer water-resistant coating is obtained after uniform stirring.The geopolymer water-resistant coating has the characteristics of high mechanical strength, low thermal conductivity, water and stain resistance, good thermal stability, and the like, and has a simple preparation process, and has a wide prospect in the fields of the building industry and road painting.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of coating preparation, and relates to preparation of a geopolymer coating, in particular to a geopolymer water-resistant coating modified by organic silicon and a preparation method thereof. BACKGROUND

[0002] Coatings are widely used in the fields of building, automobile, ship, machinery and the like, and have a huge market value. In recent years, geopolymer functional materials have attracted market attention due to advantages such as excellent environmental protection, excellent mechanical strength, high-temperature resistance and low cost. The materials are mainly prepared by alkali activation of calcined clay, natural minerals, industrial waste, fly ash and other silicate raw materials. Compared with traditional cement, the geopolymer coating has more excellent environmental benefits, can reduce 40% of carbon dioxide gas in the building, and has a broad application prospect. However, the traditional geopolymer has poor hydrophobicity and long gel time, which seriously limits its application in the coating field. SUMMARY

[0003] In view of the deficiencies of the prior art, the purpose of the present application is to provide a geopolymer water-resistant coating. The present application uses potassium silicate water glass as a curing base, and organic silicon modified water-based polyurethane emulsion as an auxiliary adhesive and waterproof reinforcing agent to prepare a geopolymer waterproof coating. The preparation operation is simple, the cost is low and easy to obtain, the hardness is good, the durability is strong, the waterproof performance is high, and the coating is green and environmentally friendly.

[0004] The present application is achieved by the following technical solutions:

[0005] A geopolymer water-resistant coating is prepared from the following raw materials by weight:

[0006] 100 parts of potassium silicate aqueous solution, 10-80 parts of filler, 0-20 parts of color paste, 0.5-2 parts of auxiliary agent, 5-20 parts of organic silicon modified water-based polyurethane emulsion, and 10-30 parts of water;

[0007] The organic silicon modified water-based polyurethane emulsion is modified by using a new type of organic silicon modifier during preparation. The structure of the new type of organic silicon modifier is:

[0008] .

[0009] Further improved schemes of the present application are as follows:

[0010] The new type of organic silicon modifier is prepared by mixing hexanediamine and 3-glycidyloxypropyltrimethoxysilane at a molar ratio of 1:3.9-4.0.

[0011] Further, the preparation process of the organic silicon modified waterborne polyurethane emulsion is as follows: after the aliphatic diisocyanate and the oligomeric diol are stirred and mixed, the temperature is raised to 70-90 DEG C under nitrogen protection, and reaction is carried out for 0.5-1.5 hours; then a new type of organic silicon modifier is added, and stirring reaction is continuously carried out for 0.5-1.5 hours; then dimethylol butyric acid hydrophilic chain extender, organic bismuth catalyst and acetone are added, and gradual polymerization reaction is carried out at 70-90 DEG C for 0.5-1.5 hours; then the temperature is lowered to room temperature, and the system is self-emulsified and dispersed in metered water under rapid stirring; after the system becomes a semi-transparent homogeneous liquid, ethylenediamine is added for chain extension; then the temperature is raised to 50-60 DEG C, and acetone is removed under low pressure, so that the organic silicon modified waterborne polyurethane emulsion is obtained.

[0012] Further, the aliphatic diisocyanate is one or more than two kinds of mixture of isophorone diisocyanate, hexamethylene diisocyanate, 4,4-dicyclohexyl methane diisocyanate or methylcyclohexyl diisocyanate.

[0013] Further, the oligomeric diol is one or more than two kinds of mixture of polytetrahydrofuran ether diol, polyethylene glycol adipate diol or polycarbonate diol.

[0014] Further, the modulus of the potassium silicate aqueous solution is 2-5.

[0015] Further, the filler is one or more than two kinds of mixture of light calcium carbonate, metakaolin, quartz powder or rutile titanium dioxide.

[0016] Further, the auxiliary agent is composed of the following components by weight: antifreeze 0.5-1.8 parts, dispersant 0.1-0.4 parts, and defoaming agent 0.1-0.2 parts.

[0017] Further improvement of the present application is:

[0018] A preparation method of a geopolymer water-resistant coating, comprising the following steps: water is mixed with fillers, color paste and auxiliary agents to form a colloidal mixture, and then the colloidal mixture is added to the organic silicon modified waterborne polyurethane emulsion under stirring, and then potassium silicate aqueous solution is added after uniform mixing, so that the geopolymer water-resistant coating is obtained.

[0019] The present application has the following advantages:

[0020] 1. The application adopts a new type of organic silane modifier containing hydroxyl and siloxane groups; in the synthesis of water-based polyurethane emulsion, the hydroxyl groups can be polycondensed with isocyanate, and each silane molecule contains four hydroxyl groups, which can be used as crosslinking points to form a modified polyurethane polymer with a body shape; the hydrophobic siloxane groups are wrapped inside the hydrophilic polyhydric alcohol chain to form a core, effectively avoiding the hydrolysis reaction of the siloxane groups, and only when the coating is prepared and coated, due to the volatilization of water, the emulsion breaks, the siloxane groups are exposed, and the silanol is formed by hydrolysis, and then the silanol groups in the potassium silicate, sand, cement and other substrates are polycondensed, thereby obtaining a water-resistant coating with high adhesion.

[0021] 2. The new type of organic silane modifier used in the application contains a hydrophobic chain, which improves the hydrophobicity and water resistance of the coating.

[0022] 3. The application not only avoids the use of organic solvents, but also does not emit toxic gases and greenhouse gases during the production process, so that the coating well embodies the environmental protection characteristics. DETAILED DESCRIPTION

[0023] The application will be described in detail below in combination with specific examples.

[0024] Example 1: Preparation of a new type of organic silane modifier

[0025] 230g of 3-glycidyloxypropyltrimethoxysilane was placed in a three-necked flask, and 28g of hexanediamine was slowly added during stirring (mixed at a molar ratio of 1:4), and then nitrogen was introduced for protection. The mixture was continuously stirred at room temperature for 8h to obtain a new type of organic silane modifier in a viscous state.

[0026] Example 2: Preparation of an organic silicon modified water-based polyurethane emulsion

[0027] 50g of polytetrahydrofuran ether diol was placed in a three-necked flask, and then 24g of isophorone diisocyanate was added. Nitrogen was introduced for protection, and the temperature was raised to 40 o C. Mechanical stirring was performed for 1h, and then the temperature was raised to 85 o C. A bismuth organic catalyst was slowly added for step-by-step polymerization reaction for 0.5h. Then 8.2g of the organic silicon modifier prepared in Example 1 was added to the flask, and the stirring reaction was continued for 1h. Then 5.8g of a hydrophilic chain extender of dihydroxymethyl butyric acid was added, and the reaction was continued at 85 o C for 1h. An appropriate amount of acetone was added to adjust the viscosity during the reaction. Then the temperature was gradually lowered to room temperature, and the system was quickly stirred and self-emulsified in 300g of deionized water. When the system became a translucent and uniform mixed solution, 0.8g of ethylenediamine was added for chain extension, and 2g of an amide neutralizing agent was added. Finally, the temperature was raised to 50~60 o C, and the acetone was removed in a low-pressure environment to obtain an organic silicon modified water-based polyurethane emulsion.

[0028] Example 3: Preparation of geopolymeric water-resistant coating

[0029] Under the ambient temperature, 30 g of deionized water was weighed in a beaker, 18 g of metakaolin powder with a particle size of 1250 mesh was added, and stirred at 500 r / min for 15 min, then 3 g of titanium oxide was added to form a uniform white suspension; then 0.5 g of antifreeze propylene glycol, 0.2 g of polyacrylic acid dispersant, and 0.1 g of polysiloxane defoaming agent were added dropwise to form a gel-like mixture. Under the state of stirring, 6 g of the silicone-modified waterborne polyurethane emulsion obtained in Example 2 was added to the beaker. Stir at 600 r / min for 20 min, then add 60 g of potassium silicate solution with a modulus of 2.0, stir for 30 min to prepare a uniform and stable geopolymeric water-resistant coating.

[0030] Example 4: Preparation of geopolymeric water-resistant coating

[0031] Under the ambient temperature, 30 g of deionized water was weighed in a beaker, 18 g of metakaolin powder with a particle size of 1250 mesh was added, and stirred at 500 r / min for 15 min, then 3 g of titanium oxide was added to form a uniform white suspension; then 0.6 g of antifreeze propylene glycol, 0.2 g of polyacrylic acid dispersant, and 0.1 g of polysiloxane defoaming agent were added dropwise to form a gel-like mixture. Under the state of stirring, 10 g of the silicone-modified waterborne polyurethane emulsion obtained in Example 2 was added to the beaker. Stir at 600 r / min for 20 min, then add 80 g of potassium silicate solution with a modulus of 3.2, stir for 30 min to prepare a uniform and stable geopolymeric water-resistant coating.

[0032] Example 5: Preparation of geopolymeric water-resistant coating

[0033] Under the ambient temperature, 30 g of deionized water was weighed in a beaker, 18 g of metakaolin powder with a particle size of 1250 mesh was added, and stirred at 500 r / min for 15 min, then 3 g of titanium oxide was added to form a uniform white suspension; then 0.6 g of antifreeze propylene glycol, 0.2 g of polyacrylic acid dispersant, and 0.1 g of polysiloxane defoaming agent were added dropwise to form a gel-like mixture. Under the state of stirring, 18 g of the silicone-modified waterborne polyurethane emulsion obtained in Example 2 was added to the beaker. Stir at 600 r / min for 20 min, then add 80 g of potassium silicate solution with a modulus of 3.2, stir for 30 min to prepare a uniform and stable geopolymeric water-resistant coating.

[0034] Example 6: Preparation of geopolymeric water-resistant coating

[0035] At room temperature, 30 g of deionized water was weighed in a beaker, 18 g of metakaolin powder with a particle size of 1250 mesh was added, and it was stirred at 500 r / min for 15 min, then 3 g of titanium oxide was added to form a uniform white suspension; then 0.6 g of antifreezing agent propylene glycol, 0.2 g of polyacrylic acid dispersant, and 0.1 g of polysiloxane defoaming agent were added dropwise to form a gel-like mixture. Under stirring, 10 g of the organic silicon modified waterborne polyurethane emulsion obtained in Example 2 was added to the beaker. Stirring at 600 r / min for 20 min, then 80 g of potassium silicate aqueous solution with a modulus of 4.0 was added, and a uniform and stable geopolymer water-resistant coating was prepared after stirring for 30 min.

[0036] Example 7: Preparation of geopolymer water-resistant coating

[0037] At room temperature, 30 g of deionized water was weighed in a beaker, 18 g of metakaolin powder with a particle size of 1250 mesh was added, and it was stirred at 500 r / min for 15 min, then 3 g of titanium oxide was added to form a uniform white suspension; then 0.6 g of antifreezing agent propylene glycol, 0.2 g of polyacrylic acid dispersant, and 0.1 g of polysiloxane defoaming agent were added dropwise to form a gel-like mixture. Under stirring, 10 g of the organic silicon modified waterborne polyurethane emulsion obtained in Example 2 was added to the beaker. Stirring at 600 r / min for 20 min, then 60 g of potassium silicate aqueous solution with a modulus of 2.0 was added, and a uniform and stable geopolymer water-resistant coating was prepared after stirring for 30 min.

[0038] Comparative Example 1:

[0039] At room temperature, 30 g of deionized water was weighed in a beaker, 18 g of metakaolin powder with a particle size of 1250 mesh was added, and it was stirred at 500 r / min for 15 min, then 3 g of titanium oxide was added to form a uniform white suspension; then 0.6 g of antifreezing agent propylene glycol, 0.2 g of polyacrylic acid dispersant, and 0.1 g of polysiloxane defoaming agent were added dropwise to form a gel-like mixture. Under stirring, 10 g of the organic silicon modified waterborne polyurethane emulsion obtained in Example 2 was added to the beaker. Stirring at 600 r / min for 20 min, then 60 g of potassium silicate aqueous solution with a modulus of 2.0 was added, and a uniform and stable geopolymer water-resistant coating was prepared after stirring for 30 min.

[0040] Preparation of coating and performance test

[0041] The slurries of Examples 3 to 7 were taken and coated on a glass substrate with a 100 um wire bar to form a film, and then the completed sample was placed in an oven, 80 o After drying, it was taken out and cooled to room temperature, and the performance test was carried out according to the standard JGT26-2002.

[0042] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent transformation or modification made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A geopolymeric water-resistant coating, characterized in that, It is prepared from the following raw materials by weight: 100 parts of potassium silicate aqueous solution, 10-80 parts of filler, 0-20 parts of color paste, 0.5-2 parts of additive, 5-20 parts of organic silicon modified water-based polyurethane emulsion, and 10-30 parts of water; The modulus of the potassium silicate aqueous solution is 2-5; The filler is one or more than two kinds of mixture of light calcium carbonate, metakaolin, quartz powder or rutile titanium dioxide; The additive is composed of the following components by weight: 0.5-1.8 parts of antifreeze, 0.1-0.4 parts of dispersant, and 0.1-0.2 parts of defoaming agent; The organic silicon modified water-based polyurethane emulsion is modified by using an organic silicon modifier during preparation, and the structure of the organic silicon modifier is: ； Specifically, the preparation process of the organic silicon modified water-based polyurethane emulsion is as follows: after the aliphatic diisocyanate and the oligomeric diol are stirred and mixed, the temperature is raised to 70-90℃ under nitrogen protection, and the reaction is carried out for 0.5-1.5 hours; then the organic silicon modifier is added, and the stirring reaction is continued for 0.5-1.5 hours; then the dimethylol butyric acid hydrophilic chain extender, organic bismuth catalyst and acetone are added, and the step-by-step polymerization reaction is carried out at 70-90℃ for 0.5-1.5 hours; then the temperature is lowered to room temperature, and the system is self-emulsified and dispersed in the measured water under rapid stirring; after the system becomes a semi-transparent homogeneous liquid, the ethylenediamine is added for chain extension; then the temperature is raised to 50-60℃, and the acetone is removed under low pressure to obtain the organic silicon modified water-based polyurethane emulsion.

2. The geopolymeric water-resistant coating according to claim 1, characterized in that: The organic silicon modifier is prepared by mixing hexamethylene diamine and 3-glycidyloxypropyl trimethoxysilane at a molar ratio of 1:3.9-4.

0.

3. The geopolymeric water-resistant coating according to claim 1, characterized in that: The aliphatic diisocyanate is one or more than two kinds of mixture of isophorone diisocyanate, hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate or methylcyclohexyl diisocyanate.

4. The geopolymeric water-resistant coating according to claim 1, characterized in that: The oligomeric diol is one or more than two kinds of mixture of polytetrahydrofuran ether diol, polyethylene glycol adipate diol or polycarbonate diol.

5. A method for preparing a geopolymeric water-resistant coating according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: The water is mixed with the filler, color paste and additive to form a colloidal mixture, which is then added to the organic silicon modified water-based polyurethane emulsion under stirring, and then the potassium silicate aqueous solution is added after uniform mixing, to obtain the geopolymer water-resistant coating.

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