A lithium silicate-based inorganic resin, a method for synthesizing the same, and an application thereof

Abstract

The application discloses a lithium silicate-based inorganic resin and a synthesis method and application thereof. The inorganic resin comprises 30-60 parts of a lithium silicate solution, 1-5 parts of 3-urea propyl triethoxysilane, 10-30 parts of a lithium hydroxide solution, 5-20 parts of gamma-aminopropyl triethoxysilane and 5-20 parts of methyl triethoxysilane. The obtained inorganic resin has good stability and weather resistance. In the synthesis method of the lithium silicate-based inorganic resin, the lithium silicate solution is first added and stirred, then the 3-urea propyl triethoxysilane is added to perform coupling reaction, then the lithium hydroxide solution is added to adjust pH, and then the gamma-aminopropyl triethoxysilane and the methyl triethoxysilane are added to perform hydrolysis reaction. After cooling, the lithium silicate-based inorganic resin is prepared. The inorganic resin is used for preparing paint, does not cause wall surface efflorescence and whiteness, significantly improves the aesthetic effect of the wall surface, and can improve the weather resistance of the paint.

Description

Technical Field

[0001] This invention relates to the field of inorganic coating resin technology, specifically to a lithium silicate-based inorganic resin, its synthesis method, and its application. Background Technology

[0002] Lithium silicate-based inorganic coatings belong to the silicate inorganic coating category. Other silicate-based inorganic coatings include potassium silicate and sodium silicate-based coatings. Sodium silicate is rarely used in inorganic coatings due to its poor water resistance. Potassium silicate is the most widely used. However, potassium silicate also has shortcomings in water resistance. When exposed to moisture or humid air, potassium ions migrate to the surface of interior and exterior wall coatings based on potassium silicate, causing a white frost to gradually form on the wall. This affects both the appearance and the coating's performance due to ion migration, making potassium silicate-based coatings mostly suitable only for use in interior white wall coatings. Lithium silicate-based inorganic coatings exhibit excellent water resistance, overcoming the shortcomings of sodium silicate and potassium silicate-based inorganic coatings. However, inorganic coatings made from lithium silicate are brittle and prone to cracking. Furthermore, due to the weak adhesion of lithium silicate, the amount of pigments and fillers used is relatively small, resulting in low hiding power. Most importantly, lithium silicate-based inorganic coatings have poor storage stability, making it difficult to produce long-term (12-month shelf life) stable products, and their application performance is also insufficient. Therefore, there are very few lithium silicate-based inorganic coating products on the market. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, one objective of this invention is to provide a lithium silicate-based inorganic resin with advantages of high strength, high toughness, and good stability, which can also self-dry to form a film and avoid white bloom phenomenon; another objective of this invention is to provide a method for synthesizing lithium silicate-based inorganic resin, which has simple steps and mild reaction conditions; a third objective of this invention is to provide an application of lithium silicate-based inorganic resin, wherein coatings produced using this resin as a base material have excellent coating performance.

[0004] One of the objectives of this invention is achieved through the following technical solution:

[0005] A lithium silicate-based inorganic resin comprises the following raw materials in parts by weight: 30-60 parts lithium silicate solution, 1-5 parts 3-ureapropyltriethoxysilane, 10-30 parts lithium hydroxide solution, 5-20 parts γ-aminopropyltriethoxysilane, and 5-20 parts methyltriethoxysilane.

[0006] Furthermore, the concentration of the lithium silicate solution is 20-25%, and the modulus is 4-10.

[0007] Furthermore, the concentration of the lithium hydroxide solution is 5-15%.

[0008] Furthermore, the lithium silicate-based inorganic resin also includes 0.1 to 10 parts of organosilicon resin.

[0009] Furthermore, the silicone resin is a silicone resin emulsion containing methyl and phenyl groups.

[0010] Furthermore, the lithium silicate-based inorganic resin also includes 0.1 to 10 parts of silicone-acrylic emulsion.

[0011] The second objective of this invention is achieved by the following technical solution:

[0012] The above-mentioned method for synthesizing lithium silicate-based inorganic resin includes the following steps:

[0013] 1) Add lithium silicate solution to the thermostat and stir;

[0014] 2) Add 3-ureapropyltriethoxysilane, then add lithium hydroxide solution to adjust the pH to 11-12.5;

[0015] 3) Continue to add γ-aminopropyltriethoxysilane, then add methyltriethoxysilane, stir and react, and after cooling, the lithium silicate-based inorganic resin is obtained.

[0016] Furthermore, in step 1), the temperature is controlled at 50-60℃ by the constant temperature device; in step 3), after adding methyltriethoxysilane, the mixture is stirred for 1-2 hours.

[0017] Furthermore, in step 3), after adding methyltriethoxysilane and stirring to react, silicone resin and / or silicone-acrylic emulsion are added, and the reaction is stirred for 2-3 hours.

[0018] The third objective of this invention is achieved by the following technical solution:

[0019] The above-mentioned applications of lithium silicate-based inorganic resins include the preparation of coatings.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) The main component of the lithium silicate-based inorganic resin of the present invention is lithium silicate solution. Lithium ions react with CO2 dissolved in water to form lithium carbonate, which is sparingly soluble in water. Its solubility at room temperature is almost negligible. Furthermore, 3-ureapropyltriethoxysilane, γ-aminopropyltriethoxysilane, and methyltriethoxysilane are utilized. right Lithium silicate is modified, thereby greatly improving the stability of the inorganic resin of this invention. 3-Ureapropyltriethoxysilane is selected as the coupling agent; lithium hydroxide solution has good stability and is not easily volatile, and is used to adjust the pH value. γ-Aminopropyltriethoxysilane and methyltriethoxysilane are used to initiate the hydrolysis reaction, thereby improving the stability of the inorganic resin.

[0022] (2) The lithium silicate-based inorganic resin of the present invention also incorporates organosilicon resin and silicone-acrylic emulsion. Due to the physicochemical effects of the silane coupling agent and silane hydrolysate in the lithium silicate-based inorganic resin, the long-chain organosilicon resin or silicone-acrylic emulsion bonds with the inorganic resin to form a longer-chain inorganic composite resin. This resin has better toughness and adhesion to the substrate. It is precisely because of the addition of organosilicon resin or silicone-acrylic emulsion to form a longer-chain lithium silicate-based inorganic composite resin that the resin and the inorganic coatings made from it have better performance stability.

[0023] (3) In the synthesis method of the lithium silicate-based inorganic resin of the present invention, a lithium silicate solution is first added and stirred, then 3-ureapropyltriethoxysilane is added for coupling reaction, followed by the addition of lithium hydroxide solution to adjust the pH to 11-12.5, and then γ-aminopropyltriethoxysilane and methyltriethoxysilane are added sequentially for hydrolysis reaction. After cooling, the lithium silicate-based inorganic resin is obtained. Adding a silane coupling agent to the lithium silicate solution first allows the coupling agent to first couple with the lithium silicate, which increases the stability of lithium silicate under temperature and pH changes, and also allows it to bond with the hydrolysis products in time during the subsequent silane hydrolysis, forming a longer-chain inorganic resin. This long-chain inorganic resin has better toughness, higher strength, and more stable performance than lithium silicate alone. Therefore, coatings made with this synthesized lithium silicate-based inorganic resin have better stability than coatings made with lithium silicate, greatly improving the product stability of lithium silicate-based inorganic coatings.

[0024] Lithium hydroxide solution is used to adjust the pH value because it is not easily volatile and avoids the problem of potassium hydroxide and sodium hydroxide introducing potassium and sodium ions that can cause alkali return.

[0025] (4) The lithium silicate-based inorganic resin of the present invention is used to prepare coatings. Lithium ions are relatively stable and will not migrate from the interior of the coating to the surface with water. Therefore, it fundamentally avoids the drawbacks of most potassium silicate inorganic coatings, such as efflorescence, whitening, and mottled appearance of the wall surface caused by the precipitation of potassium ions, and significantly improves the aesthetic effect of the wall surface. In addition, since 3-ureapropyltriethoxysilane, γ-aminopropyltriethoxysilane, and methyltriethoxysilane are used to modify lithium silicate, the stability of the coating is greatly enhanced, thereby improving the weather resistance of the coating. It also has the excellent self-cleaning effect and stain resistance of inorganic coatings, and therefore has great application prospects in practical applications. Detailed Implementation

[0026] The present invention will now be further described in conjunction with specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0027] The specific formulations of lithium silicate-based inorganic resins in Examples 1-5 are shown in Table 1.

[0028] Table 1. Formulations (parts by weight) of lithium silicate-based inorganic resins in Examples 1-5

[0029]

[0030]

[0031] The silicone resin is a methyl and phenyl silicone resin emulsion manufactured by Wacker and model number 50E.

[0032] The synthesis methods of lithium silicate-based inorganic resins in Examples 1 and 2 include the following steps:

[0033] 1) Add lithium silicate solution into the thermostat and control the temperature at 50-60℃ while stirring;

[0034] 2) Add 3-ureapropyltriethoxysilane, then add lithium hydroxide solution to adjust the pH to 11-12.5;

[0035] 3) Continue to add γ-aminopropyltriethoxysilane, then add methyltriethoxysilane, stir and react for 2 hours, and after cooling, the lithium silicate-based inorganic resin is obtained.

[0036] The synthesis methods of lithium silicate-based inorganic resins in Examples 3 and 4 include the following steps:

[0037] 1) Add lithium silicate solution into the thermostat and control the temperature at 50-60℃ while stirring;

[0038] 2) Add 3-ureapropyltriethoxysilane, then add lithium hydroxide solution to adjust the pH to 11-12.5;

[0039] 3) Continue adding γ-aminopropyltriethoxysilane, then add methyltriethoxysilane, and stir the reaction for 2 hours;

[0040] 4) Add silicone resin and / or silicone-acrylic emulsion, stir and react for 3 hours, and then cool to obtain the lithium silicate-based inorganic resin.

[0041] Comparative Example 1

[0042] The difference between Comparative Example 1 and Example 5 is that in Comparative Example 1, the lithium silicate solution was replaced with a potassium silicate solution. The remaining components and synthesis methods are the same as in Example 5.

[0043] Comparative Example 2

[0044] The difference between Comparative Example 2 and Example 5 is that the lithium hydroxide solution in Comparative Example 2 is replaced with ammonia, while the remaining components and synthesis methods are the same as in Example 5.

[0045] Comparative Example 3

[0046] The difference between Comparative Example 3 and Example 5 is that in Comparative Example 3, the lithium hydroxide solution was replaced with potassium hydroxide solution, while the remaining components and synthesis methods were the same as in Example 5.

[0047] Comparative Example 4

[0048] The difference between Comparative Example 4 and Example 5 is that the synthesis method of Comparative Example 4 is hydrolysis followed by coupling, including the following steps:

[0049] 1) Add lithium silicate solution into the thermostat and control the temperature at 50-60℃ while stirring;

[0050] 2) Add γ-aminopropyltriethoxysilane and methyltriethoxysilane, and stir for 2 hours. In this Comparative Example 4, the resin had already gelled and solidified in step 2), so the subsequent coupling step could not be carried out. That is, hydrolysis followed by coupling cannot produce a fluid coating.

[0051] Performance testing

[0052] Take 20 parts of the inorganic resin from Examples 1-5 and Comparative Examples 1-3, and add 30 parts of deionized water, 0.1 parts of dispersant, 0.32 parts of wetting agent, 5 parts of diatomaceous earth, 10 parts of acrylic solution, 0.5 parts of film-forming aid, and 0.5 parts of leveling agent to prepare coatings. The performance of the coatings was tested, and the results are shown in Table 2. Then, take the coatings from Examples 1-5 and let them stand at room temperature (20-30℃) for 3 months, 6 months, 8 months, 12 months, and 18 months respectively, observing whether the coatings showed any clumping, agglomeration, or mold growth in the containers. The results are shown in Table 3.

[0053] Table 2 shows the performance data of the coatings used in Examples 1-5 and Comparative Examples 1-3.

[0054]

[0055]

[0056] Table 3 shows the condition of the coatings in Examples 1-5 after prolonged storage.

[0057]

[0058] As shown in Table 2, Comparative Example 1 replaced lithium silicate solution with potassium silicate solution. Potassium silicate reacts with dissolved CO2 in water to form potassium carbonate. Potassium carbonate has high solubility, so it migrates from the interior of the coating to the surface with the water, thus Comparative Example 1 fails the water resistance test. Comparative Example 2 replaced lithium hydroxide with ammonia. Ammonia is volatile, has poor heat resistance, and causes the coating to separate after evaporation. Comparative Example 3 replaced potassium hydroxide with lithium hydroxide solution, introducing potassium ions. Potassium ions are easily soluble in water, resulting in poor water resistance of the coating. Comparative Example 4 involved hydrolysis followed by coupling, which affects the stability and heat resistance of the coating. Therefore, coatings using the inorganic resins of Examples 1-5 as raw materials all exhibit good weather resistance and stability, meeting the coating standards.

[0059] As shown in Table 3, Examples 1 and 2, lacking both silicone resin and silicone-acrylic emulsion, exhibited clumping after 12 months of storage. Examples 3 and 4, each containing only one of silicone resin and silicone-acrylic emulsion, could only be stably stored for 12 months. Example 5, due to the addition of both silicone resin and silicone-acrylic emulsion, could be stably stored for 18 months, indicating that silicone resin and silicone-acrylic emulsion effectively improve the stability of the coating.

[0060] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A lithium silicate-based inorganic resin, characterized in that, It includes the following raw materials in parts by weight: 30-60 parts lithium silicate solution, 1-5 parts 3-ureapropyltriethoxysilane, 10-30 parts lithium hydroxide solution, 5-20 parts γ-aminopropyltriethoxysilane, and 5-20 parts methyltriethoxysilane; it also includes: 0.1-10 parts of organosilicon resin emulsion containing methyl and phenyl groups, and 0.1-10 parts of silicone-acrylic emulsion; The concentration of the lithium silicate solution is 20-25%, and the modulus is 4-10; The concentration of the lithium hydroxide solution is 5-15%; The pH adjuster of the lithium silicate-based inorganic resin is only lithium hydroxide solution, and the system does not contain potassium-containing alkaline compounds, sodium-containing alkaline compounds, or ammonia-like alkaline substances. The method for synthesizing the lithium silicate-based inorganic resin includes the following steps: 1) Add lithium silicate solution into the constant temperature device and stir at a constant temperature of 50~60℃; 2) First, add 3-ureapropyltriethoxysilane to carry out the coupling reaction, then add lithium hydroxide solution to adjust the pH to 11~12.5; 3) Add γ-aminopropyltriethoxysilane and methyltriethoxysilane sequentially, and carry out the hydrolysis reaction with stirring for 1-2 hours; 4) After the hydrolysis reaction is completed, add organosilicon resin emulsion containing methyl and phenyl groups and silicone-acrylic emulsion, stir and react for 2-3 hours, and after cooling, the lithium silicate-based inorganic resin is obtained.

2. The application of the lithium silicate-based inorganic resin according to claim 1, characterized in that, Lithium silicate-based inorganic resins are used to prepare coatings.

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