Nanosilicon crystal strong formaldehyde-free cementing material for building

Abstract

The application provides a building nanometer silicon crystal strong formaldehyde-free cementing material and belongs to the technical field of building materials. The building nanometer silicon crystal strong formaldehyde-free cementing material comprises A component and B component. The A component comprises the following raw materials in parts by weight: silicate 80-120 parts, bauxite 10-15 parts, alunite 5-8 parts and calcium aluminate 3-8 parts. The B component comprises the following raw materials in parts by weight: polyvinyl alcohol 1-5 parts, silica sol 3-50 parts, triethanolamine 0.1-2 parts and water 50-90 parts. In the application, the silica sol and the polyvinyl alcohol construct a stable organic-inorganic interpenetrating network, which can significantly improve the bonding effect of the cementing material. After 48h of water immersion treatment, the bonding strength can still be kept high, and the application is suitable for environments, such as tunnel engineering, basement and outer wall, which are in long-term contact with water.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a strong, formaldehyde-free nano-silicon crystal bonding material for building applications. Background Technology

[0002] Currently, various adhesive materials are widely used in building exterior wall insulation boards and decoration projects for bonding insulation boards to walls, laying finishing materials, and waterproofing and sealing. Existing adhesive materials mainly include cement-based bonding mortar, polymer-modified waterproof mortar, and two-component inorganic-organic composite adhesive materials.

[0003] Traditional cement-based bonding mortars primarily consist of ordinary silicate cement, quartz sand, and polymer powder, relying on cement hydration for strength and polymer powder for improved flexibility. However, these materials suffer from the following problems in practical applications: the cement hydration products have a rigid structure, resulting in weak interfacial bonding with the polymer film. Under temperature and humidity cycles and freeze-thaw cycles, interfacial debonding easily occurs, leading to a significant decrease in bond strength. Simultaneously, the hardened mortar contains numerous capillary pores with a high water absorption rate. Water intrusion followed by freeze-thaw cycles easily triggers expansion and cracking, manifesting as cracking, hollowing, and even detachment.

[0004] Patent application CN107673705A discloses a bonding mortar made by blending ordinary silicate cement and high-alumina cement, with added components such as fly ash, quartz sand, adhesive powder, and cellulose ether. While the introduction of high-alumina cement can accelerate the early hydration rate, the hydration products of the high-alumina cement and silicate cement composite system exhibit phase incompatibility, potentially leading to crystal transformation later on and resulting in strength reduction—that is, later strength lower than early strength—posing a safety hazard to the project. Furthermore, this system is extremely sensitive to curing humidity and temperature conditions, exhibiting poor adaptability to construction environments. In dry or low-temperature conditions, it is prone to incomplete hydration, surface efflorescence, and powdering.

[0005] Patent application CN112661461A discloses a high-strength waterproof and seepage-resistant nano-SiO2 mortar and its preparation method. The method involves preparing a mixed dispersion of nano-silica and polyvinyl alcohol, which is then stirred together with cement and sand. This method utilizes the filling effect and pozzolanic activity of nano-silica to promote cement hydration. However, nano-silica is a hydrophilic nanoparticle with a large specific surface area and high surface energy, making it prone to agglomeration in the high ionic strength alkaline environment of cement paste. Simply relying on physical stirring makes it difficult to achieve uniform dispersion of the nanoparticles, weakening its nano-reinforcing effect. Furthermore, the polyvinyl alcohol and nano-silica in this system lack chemical bonding and coexist only through physical blending. Under long-term water environment or humid heat aging conditions, the polyvinyl alcohol film easily absorbs water and swells, leading to a decrease in interfacial adhesion.

[0006] Currently available two-component adhesive materials (powder + liquid) have the following problems: First, the inorganic minerals in the powder hydrate rapidly upon contact with water, while the polymers in the liquid require a certain amount of time to form a film. The reaction kinetics of the two are mismatched, resulting in uncontrollable setting time and insufficient construction window. Second, there is a lack of chemical bonding between the inorganic hydration products and the organic polymer film, relying solely on physical adsorption. Under long-term load and environmental aging, the interface is prone to becoming a site of destruction. Third, the waterproofing and bonding components are mutually restrictive. Introducing hydrophobic components to improve waterproofing will reduce wettability and adhesion, while increasing hydrophilic components will lead to increased water absorption. It is difficult to achieve both simultaneously.

[0007] In summary, existing adhesive materials struggle to simultaneously meet the comprehensive requirements of high bond strength, excellent waterproofing, workability, and long-term durability. Therefore, researching a high-strength, formaldehyde-free nanocrystalline adhesive for construction is of great significance. Summary of the Invention

[0008] The purpose of this invention is to provide a strong, formaldehyde-free nano-silicon crystal adhesive for building applications, in order to solve the problems of low bonding strength and poor waterproofing of existing adhesives.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a high-strength, formaldehyde-free nano-silicon crystal adhesive for building applications, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 80-120 parts silicate, 10-15 parts bauxite, 5-8 parts alunite, and 3-8 parts calcium aluminate. Component B comprises the following raw materials in parts by weight: 1-5 parts polyvinyl alcohol, 3-50 parts silica sol, 0.1-2 parts triethanolamine, and 50-90 parts water.

[0010] Preferably, the silicate comprises one or more of calcium silicate, magnesium silicate, iron silicate, aluminum silicate, sodium silicate, and potassium silicate.

[0011] Preferably, component A comprises the following raw materials in parts by weight: 90-110 parts silicate, 11-14 parts bauxite, 6-7 parts alunite, and 5-6 parts calcium aluminate.

[0012] Preferably, component B comprises the following raw materials in parts by weight: 2-4 parts polyvinyl alcohol, 3-45 parts silica sol, 1 part triethanolamine, and 60-80 parts water.

[0013] Preferably, the weight ratio of component A to component B is 1:0.5~1.5.

[0014] Preferably, the polyvinyl alcohol has an average degree of polymerization of 1500 to 3000.

[0015] Preferably, component B further includes a chelating agent, wherein the chelating agent is ethylenediaminetetraacetic acid and / or aminoacetic acid.

[0016] Preferably, the chelating agent has a weight content of 8 to 15 parts.

[0017] The beneficial effects of this invention are: In this invention, silica sol and polyvinyl alcohol construct a stable organic-inorganic interpenetrating network, which can significantly improve the bonding effect of the adhesive material.

[0018] The adhesive material of the present invention can still maintain high bonding strength after 48 hours of immersion in water, which shows that the adhesive material of the present invention can effectively prevent water molecules from penetrating and maintain stable bonding performance in a water environment. It is suitable for environments that are in long-term contact with water, such as tunnel engineering, basements, and exterior walls.

[0019] This invention introduces ethylenediaminetetraacetic acid and / or glycine as chelating agents into the cementing material. Through their complexation with metal ions in the system, the hydration reaction rate of minerals such as calcium aluminate is effectively controlled, avoiding excessively rapid reactions that lead to structural inhomogeneity. At the same time, the chelating agent can stabilize the dispersion state of silica sol nanoparticles in the alkaline system, preventing irreversible aggregation and ensuring that the nano-silicon crystals are uniformly distributed in the organic-inorganic network, thus fully leveraging the filling and reinforcing effect.

[0020] The adhesive material of this invention not only exhibits excellent bonding strength to cement mortar substrates but also demonstrates good bonding performance to molded Class A fireproof insulation boards. Furthermore, all raw materials in this invention are free of formaldehyde and harmful volatile organic compounds, making it an environmentally friendly building adhesive material that aligns with the development direction of green building materials. Detailed Implementation

[0021] This invention provides a high-strength, formaldehyde-free nano-silicon crystal adhesive for building applications, comprising component A and component B. Component A comprises the following raw materials in parts by weight: 80-120 parts silicate, 10-15 parts bauxite, 5-8 parts alunite, and 3-8 parts calcium aluminate. Component B comprises the following raw materials in parts by weight: 1-5 parts polyvinyl alcohol, 3-50 parts silica sol, 0.1-2 parts triethanolamine, and 50-90 parts water.

[0022] In this invention, the silicate comprises one or more of calcium silicate, magnesium silicate, iron silicate, aluminum silicate, sodium silicate, and potassium silicate.

[0023] In this invention, component A comprises the following raw materials in parts by weight: 90-110 parts of silicate, 11-14 parts of bauxite, 6-7 parts of alunite, and 5-6 parts of calcium aluminate.

[0024] In this invention, component B comprises the following raw materials in parts by weight: 2-4 parts polyvinyl alcohol, 3-45 parts silica sol, 1 part triethanolamine, and 60-80 parts water.

[0025] In this invention, the weight ratio of component A to component B is 1:0.5~1.5, preferably 1:0.8~1.2, and more preferably 1:1.

[0026] In this invention, the average degree of polymerization of the polyvinyl alcohol is 1500~3000, preferably 1600~2500, and more preferably 1700~2000.

[0027] In this invention, component B further includes a chelating agent, wherein the chelating agent is ethylenediaminetetraacetic acid and / or aminoacetic acid.

[0028] In this invention, the chelating agent is present in a weight ratio of 8 to 15 parts, preferably 9 to 12 parts, and more preferably 10 to 11 parts.

[0029] In this invention, the method of using the nano-silicon crystal strong formaldehyde-free adhesive for building is as follows: polyvinyl alcohol and water are mixed, and then silica sol and triethanolamine are added to obtain component B; silicate, bauxite, alunite and calcium aluminate are mixed to obtain component A; finally, component A and component B are mixed evenly according to the weight ratio to obtain the nano-silicon crystal strong formaldehyde-free adhesive for building.

[0030] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0031] Example 1

[0032] Component A: 100 parts calcium silicate, 12 parts bauxite, 6 parts alunite, and 5 parts calcium aluminate; Component B: 3 parts polyvinyl alcohol, 30 parts silica sol, 1 part triethanolamine, and 70 parts water, wherein the degree of polymerization of polyvinyl alcohol is 1700.

[0033] First, polyvinyl alcohol and water are mixed and stirred at 80°C until the polyvinyl alcohol is completely dissolved. After cooling, silica sol and triethanolamine are added to obtain component B. Calcium silicate, bauxite, alunite and calcium aluminate are placed in a mixer and stirred evenly to obtain component A. Finally, component A and component B are mixed evenly at a weight ratio of 1:1 to obtain a strong formaldehyde-free nano-silicon crystal adhesive for building.

[0034] Example 2

[0035] Component A: 100 parts calcium silicate, 12 parts bauxite, 6 parts alunite, and 5 parts calcium aluminate; Component B: 3 parts polyvinyl alcohol, 40 parts silica sol, 1 part triethanolamine, and 70 parts water, wherein the degree of polymerization of polyvinyl alcohol is 1700.

[0036] Example 3

[0037] Component A: 100 parts calcium silicate, 12 parts bauxite, 6 parts alunite, and 5 parts calcium aluminate; Component B: 3 parts polyvinyl alcohol, 50 parts silica sol, 1 part triethanolamine, and 70 parts water, wherein the degree of polymerization of polyvinyl alcohol is 1700.

[0038] Example 4

[0039] Component A: 100 parts calcium silicate, 12 parts bauxite, 6 parts alunite, and 5 parts calcium aluminate; Component B: 3 parts polyvinyl alcohol, 40 parts silica sol, 1 part triethanolamine, 8 parts ethylenediaminetetraacetic acid, and 70 parts water, wherein the degree of polymerization of polyvinyl alcohol is 1700.

[0040] Example 5

[0041] Component A: 100 parts calcium silicate, 12 parts bauxite, 6 parts alunite, and 5 parts calcium aluminate; Component B: 3 parts polyvinyl alcohol, 40 parts silica sol, 1 part triethanolamine, 12 parts ethylenediaminetetraacetic acid, and 70 parts water, wherein the degree of polymerization of polyvinyl alcohol is 1700.

[0042] Example 6

[0043] Component A: 100 parts calcium silicate, 12 parts bauxite, 6 parts alunite, and 5 parts calcium aluminate; Component B: 3 parts polyvinyl alcohol, 40 parts silica sol, 1 part triethanolamine, 12 parts glycine, and 70 parts water, wherein the degree of polymerization of polyvinyl alcohol is 1700.

[0044] Comparative Example 1

[0045] The difference from Example 1 is that the amount of silica sol used is 20 parts by weight, while all other conditions are the same.

[0046] Comparative Example 2

[0047] The difference from Example 1 is that the amount of silica sol used is 60 parts by weight, while all other conditions are the same.

[0048] Comparative Example 3

[0049] The difference from Example 4 is that the amount of ethylenediaminetetraacetic acid used is 3 parts by weight, while all other conditions are the same.

[0050] Comparative Example 4

[0051] The difference from Example 4 is that the amount of ethylenediaminetetraacetic acid used is 20 parts by weight, while all other conditions are the same.

[0052] Performance test results of the bonding materials in Examples 1-6 and Comparative Examples 1-4

[0053] Comparing Examples 1-3 and Comparative Examples 1-2, it can be seen that the amount of silica sol affects the tensile bond strength. This may be because if the amount of silica sol is too low, a complete inorganic silicon network structure cannot be formed, and the reinforcing effect of nano-silicon crystals cannot be fully utilized. On the other hand, if the amount of silica sol is too high, it may lead to uncontrollable agglomeration and gelation, which will destroy the uniformity of the organic-inorganic interpenetrating network structure and is not conducive to improving the bond strength.

[0054] Comparing the test results of Examples 2 and 4-6, it can be seen that the introduction of chelating agents can improve the performance of the cementitious materials, resulting in excellent water resistance and bonding properties. Combined with Comparative Examples 3 and 4, it can be seen that insufficient chelating agent dosage cannot fully exert its complexing and regulating effect, while excessive chelating agent dosage may over-complex calcium ions in the system, thereby inhibiting the normal hydration reaction of minerals such as calcium aluminate, which is detrimental to improving the bonding strength.

[0055] The operable time of the nano-silicon crystal strong formaldehyde-free cementitious material for building of the present invention is 1.0~1.5h.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-strength, formaldehyde-free nanocrystalline cementitious material for construction, characterized in that, The building nano-silicon crystal high-strength formaldehyde-free adhesive material includes component A and component B; Component A comprises the following raw materials in parts by weight: 80-120 parts silicate, 10-15 parts bauxite, 5-8 parts alunite, and 3-8 parts calcium aluminate. Component B comprises the following raw materials in parts by weight: 1-5 parts polyvinyl alcohol, 3-50 parts silica sol, 0.1-2 parts triethanolamine, and 50-90 parts water.

2. The high-strength, formaldehyde-free nano-silicon crystal adhesive for building applications according to claim 1, characterized in that, The silicate comprises one or more of calcium silicate, magnesium silicate, iron silicate, aluminum silicate, sodium silicate, and potassium silicate.

3. The high-strength, formaldehyde-free nanocrystalline cementitious material for building applications according to claim 1 or 2, characterized in that, Component A comprises the following raw materials in parts by weight: 90-110 parts silicate, 11-14 parts bauxite, 6-7 parts alunite, and 5-6 parts calcium aluminate.

4. The high-strength, formaldehyde-free nano-silicon crystal adhesive for building applications according to claim 3, characterized in that, Component B comprises the following raw materials in parts by weight: 2-4 parts polyvinyl alcohol, 3-45 parts silica sol, 1 part triethanolamine, and 60-80 parts water.

5. The high-strength, formaldehyde-free nanocrystalline cementitious material for building applications according to claim 1, 2, or 4, characterized in that, The weight ratio of component A to component B is 1:0.5~1.

5.

6. The high-strength, formaldehyde-free nano-silicon crystal adhesive for building applications according to claim 5, characterized in that, The average degree of polymerization of the polyvinyl alcohol is 1500~3000.

7. The high-strength, formaldehyde-free nanocrystalline cementitious material for building applications according to claim 4 or 6, characterized in that, Component B further includes a chelating agent, wherein the chelating agent is ethylenediaminetetraacetic acid and / or aminoacetic acid.

8. The high-strength, formaldehyde-free nano-silicon crystal adhesive for building applications according to claim 7, characterized in that, The chelating agent has a weight content of 8 to 15 parts.

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