A laponite-based water-resistant adjuvant suitable for water-based paints and a preparation process thereof

Abstract

This invention belongs to the technical field of water-based coating water-resistant additives, specifically relating to a lithium saponite-based water-resistant additive suitable for water-based coatings and its preparation process. The additive of this invention consists of lithium saponite as the main ingredient and auxiliary ingredients, wherein the main ingredient is lithium saponite, and the auxiliary ingredients are cerium nitrate, silane coupling agent, polyacrylic acid, and deionized water. The lithium saponite-based water-resistant additive of this invention improves the water resistance of water-based coatings, increasing the water resistance time from 100 hours to 300 hours or more.

Description

Technical Field

[0001] This invention belongs to the technical field of water-resistant additives for water-based coatings, specifically a lithium saponite-based water-resistant additive suitable for water-based coatings and its preparation process. Background Technology

[0002] In recent years, my country's coatings manufacturing industry has developed rapidly, ranking first in the world in both output and consumption, with an annual output value of approximately 400 billion yuan. High-tech, low-energy-consumption, and low-pollution environmentally friendly protective coatings are increasingly attracting attention from the high-end equipment manufacturing industry. Water-based coatings represent the development trend of environmentally friendly coatings. European and American countries attach great importance to the development and application of sustainable low-VOC water-based coating additives, and have formed a complete industrial chain with a penetration rate exceeding 80%. While my country's water-based coatings industry has made significant progress in technology, with most raw materials now domestically produced, it still cannot fully replace traditional non-environmentally friendly solvent-based coating materials due to issues such as poor water resistance. The penetration rate is less than 30%, and in particular, over 70% of high-end coating materials used in high-end equipment are still monopolized by international companies. Therefore, the research and development of water-resistant technologies for water-based coatings is urgently needed.

[0003] The poor water resistance of water-based coatings is due to the hydrophilicity of the resin. To achieve dispersion, mixing, and coating in water, charged functional groups such as quaternary ammonium salts and acid radicals, or polar functional groups such as hydroxyl and carboxyl groups, are introduced into the resin molecules to prepare water-based emulsions or dispersions. Coating materials prepared with hydrophilic resins undergo swelling, deformation, and peeling under the influence of water molecules in the environment, ultimately leading to the loss of the coating's protective function. This is one of the unsolved problems worldwide. Summary of the Invention

[0004] In view of the aforementioned technical problems, the present invention provides a lithium saponite-based water-resistant additive suitable for water-based coatings and its preparation process. This additive can coat and shield the water-based components of the resin in water-based coatings, reducing the resin's hydrophilicity and thus improving the water resistance of the water-based coatings.

[0005] The technical solution of this invention is:

[0006] A lithium saponite-based water-resistant additive suitable for water-based coatings, comprising lithium saponite as the main ingredient and auxiliary ingredients; by mass parts, the main ingredient: 100 parts lithium saponite; auxiliary ingredients: 2-10 parts cerium nitrate, 5-15 parts silane coupling agent, 5-20 parts polyacrylic acid, and 100-5000 parts deionized water.

[0007] Furthermore, the lithium saponite is a powdered magnesium lithium silicate material, the cerium nitrate is chemically pure or analytically pure cerium nitrate hexahydrate, the silane coupling agent is a compound with silanoxy and amino groups on its molecule, the molecular weight of the polyacrylic acid is in the range of 2000-5000, and the conductivity of the deionized water is less than 0.5 mS / cm.

[0008] A preparation process for a lithium saponite-based water-resistant additive suitable for water-based coatings, comprising the following steps:

[0009] Step 1: Preparation of initial lithium saponite-based water-resistant additive; Step 2: Preparation of lithium saponite-based water-resistant additive; Step 3: Packaging of lithium saponite-based water-resistant additive.

[0010] Further, step 1 specifically involves: adding deionized water to a clean reactor equipped with stirring and heating functions, stirring and adding lithium saponite, and after the lithium saponite is evenly dispersed, adding cerium nitrate and stirring for 30 minutes, then adding silane coupling agent and polyacrylic acid and stirring for 30 minutes, heating to a certain temperature and stirring, and cooling to room temperature to obtain the initial lithium saponite-based water-resistant additive.

[0011] Furthermore, the heating temperature is 50-80℃, and the stirring time is 2-4 hours.

[0012] Further, step 2 specifically involves: filtering the initial lithium saponite-based water-resistant additive through a 100-300 mesh sieve to remove substances that cannot be filtered, collecting the filtered additive, and obtaining the final lithium saponite-based water-resistant additive.

[0013] Further, step 3 specifically involves injecting the final lithium soapstone-based water-resistant additive into a clean, anhydrous storage tank and sealing it for preservation.

[0014] The design concept of this invention is:

[0015] The colloidal framework of lithium saponite dispersed in deionized water ensures thorough mixing between the main ingredient, lithium saponite, and auxiliary materials such as cerium nitrate, silane coupling agent, polyacrylic acid, and deionized water, thereby maximizing the synergistic effect of the main and auxiliary materials. Cerium nitrate catalyzes the formation of a chemical bond between the main and auxiliary materials; the silane coupling agent establishes stable interfacial bonding between organic and inorganic materials; polyacrylic acid improves the compatibility of the auxiliary material with the waterborne coating resin; and deionized water provides a uniform and stable dispersion carrier for the auxiliary material. Based on these characteristics, a water-resistant additive for waterborne coatings is ultimately obtained.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0017] 1. The lithium saponite-based water-resistant additive for water-based coatings prepared by this invention has a simple preparation process, and the raw materials required for the formulation can be directly purchased from the market, resulting in low cost. The coating is suitable for various water-based coating substrates such as water-based acrylic coatings, water-based alkyd coatings, water-based epoxy coatings, water-based polyurethane coatings, and water-based amine coatings.

[0018] 2. The additive prepared by the present invention can coat and shield the water-based parts of the resin, reduce the hydrophilicity of the resin, thereby improving the water resistance of the water-based coating, increasing the water resistance time from 100 hours to 300 hours or more. Attached Figure Description

[0019] Figure 1 This is the macroscopic state of the lithium saponite-based water-resistant additive of Example 1 of the present invention.

[0020] Figure 2 The image shows the microstructure of the lithium saponite-based water-resistant additive in Example 1 of this invention.

[0021] Figure 3 The effect of lithium saponite-based water-resistant additives on the water resistance of acrylic coatings in Example 1 is shown in Figure 1 (a) Water resistance of coatings with lithium saponite-based water-resistant additives, and b) Water resistance of coatings without lithium saponite-based water-resistant additives. Detailed Implementation

[0022] The following embodiments are a further detailed description of the present invention. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] A lithium saponite-based water-resistant additive suitable for water-based coatings, comprising lithium saponite as the main ingredient and auxiliary ingredients; by mass parts, the main ingredient: 100 parts lithium saponite; auxiliary ingredients: 2-10 parts cerium nitrate, 5-15 parts silane coupling agent, 5-20 parts polyacrylic acid, and 100-5000 parts deionized water.

[0024] Furthermore, the lithium saponite is a powdered magnesium lithium silicate material, the cerium nitrate is chemically pure or analytically pure cerium nitrate hexahydrate, the silane coupling agent is a compound with silanoxy and amino groups on its molecule, the molecular weight of the polyacrylic acid is in the range of 2000-5000, and the conductivity of the deionized water is less than 0.5 mS / cm.

[0025] A preparation process for a lithium saponite-based water-resistant additive suitable for water-based coatings, comprising the following steps:

[0026] Step 1: Preparation of initial lithium saponite-based water-resistant additive: Add deionized water to a clean reactor equipped with stirring and heating functions, start stirring and add lithium saponite. After the lithium saponite is evenly dispersed, add cerium nitrate and stir for 30 minutes. Then add silane coupling agent and polyacrylic acid and stir for 30 minutes. Heat to 50-80℃ and stir for 2-4 hours. Cool to room temperature to obtain the initial lithium saponite-based water-resistant additive.

[0027] Step 2, Preparation of lithium saponite-based water-resistant additive: The initial lithium saponite-based water-resistant additive is filtered through a 100-300 mesh sieve to remove substances that cannot be filtered. The filtered additive is collected to obtain the final lithium saponite-based water-resistant additive.

[0028] Step 3, Packaging of lithium soapstone-based water-resistant additive: Pour the final lithium soapstone-based water-resistant additive into a clean, anhydrous storage container and seal it for storage; the storage container can be made of stainless steel, tinplate, fluoroplastic or glass, etc.

[0029] Example 1.

[0030] Step 1: Add 5000 kg of deionized water to a clean reactor equipped with stirring and heating functions, start stirring and add 100 kg of lithium soapstone. After the lithium soapstone is evenly dispersed, add 10 kg of chemically pure cerium nitrate and stir for 30 minutes. Add 15 kg of silane coupling agent 3-aminopropylmethyldimethoxysilane and 20 kg of polyacrylic acid with a molecular weight of 5000 and stir for 30 minutes. Heat to 80°C and stir for 4 hours. Cool to room temperature to obtain the initial lithium soapstone-based water-resistant material.

[0031] Step 2: The initial lithium saponite-based water-resistant additive is filtered through a 300-mesh sieve to remove substances that cannot be filtered. The filtered additive is collected to obtain the final lithium saponite-based water-resistant additive.

[0032] Step 3: Pour the final lithium soapstone-based water-resistant additive into a clean, anhydrous stainless steel storage tank and seal it for storage.

[0033] The lithium saponite-based water-resistant additive obtained in Example 1 was added to the waterborne acrylic coating. The waterborne acrylic coating without the additive from Example 1 was used as a blank sample. The water resistance of the waterborne acrylic coating sample was tested according to GB / T1733 "Test Method for Water Resistance of Coating Film".

[0034] like Figure 1 As shown, the prepared lithium saponite-based water-resistant additive suitable for water-based coatings has a macroscopic morphology of a milky white dispersion.

[0035] like Figure 2 The microstructure of the prepared lithium saponite-based water-resistant additive suitable for water-based coatings is shown in the figure, with auxiliary materials distributed on the main material lithium saponite.

[0036] like Figure 3 As shown, the addition of a lithium saponite-based water-resistant additive suitable for water-based coatings increases the water resistance time of acrylic coatings from 100 hours to 300 hours.

[0037] Example 2.

[0038] Step 1: Add 100 kg of deionized water to a clean reactor equipped with stirring and heating functions, start stirring and add 100 kg of lithium soapstone. After the lithium soapstone is evenly dispersed, add 2 kg of chemically pure cerium nitrate and stir for 30 minutes. Add 15 kg of silane coupling agent 3-aminopropylmethyldiethoxysilane and 20 kg of polyacrylic acid with a molecular weight of 2000 and stir for 30 minutes. Heat to 50°C and stir for 2 hours. Cool to room temperature to obtain the initial lithium soapstone-based water-resistant material.

[0039] Step 2: Filter the slurry through a 100-mesh sieve to remove substances that cannot be filtered out. Collect the filtered slurry to obtain the final lithium soapstone-based water-resistant additive.

[0040] Step 3: Pour the final lithium soapstone-based water-resistant additive into a clean, anhydrous tinplate storage container and seal it for storage.

[0041] The lithium saponite-based water-resistant additive obtained in Example 2 was added to the waterborne acrylic coating. The waterborne acrylic coating without the additive from Example 2 was used as a blank sample. The water resistance of the waterborne acrylic coating sample was tested according to GB / T1733 "Test Method for Water Resistance of Coating Film".

[0042] The addition of lithium saponite-based water-resistant additives suitable for water-based coatings improves the water resistance of acrylic coatings by 300 hours.

[0043] Example 3.

[0044] Step 1: Add 1000 kg of deionized water to a clean reactor equipped with stirring and heating functions, start stirring and add 100 kg of lithium soapstone. After the lithium soapstone is evenly dispersed, add 5 kg of analytical grade cerium nitrate and stir for 30 minutes. Add 10 kg of silane coupling agent 3-aminopropyltrimethoxysilane and 20 kg of polyacrylic acid with a molecular weight of 4000 and stir for 30 minutes. Heat to 60°C and stir for 3 hours. Cool to room temperature to obtain the initial lithium soapstone-based water-resistant material.

[0045] Step 2: The final lithium soapstone-based water-resistant additive is filtered through a 200-mesh sieve to remove substances that cannot be filtered. The filtered slurry is then collected to obtain the filtered slurry.

[0046] Step 3: Pour the final lithium soapstone-based water-resistant additive into a clean, anhydrous glass storage container and seal it for storage.

[0047] The lithium saponite-based water-resistant additive obtained in Example 3 was added to the waterborne acrylic coating. The waterborne acrylic coating without the additive from Example 3 was used as a blank sample. The water resistance of the waterborne acrylic coating sample was tested according to GB / T1733 "Test Method for Water Resistance of Coating Film".

[0048] The addition of lithium saponite-based water-resistant additives suitable for water-based coatings improves the water resistance of acrylic coatings by 300 hours.

[0049] Example 4.

[0050] Step 1: Add 2000 kg of deionized water to a clean reactor equipped with stirring and heating functions, start stirring and add 100 kg of lithium soapstone. After the lithium soapstone is evenly dispersed, add 8 kg of chemically pure cerium nitrate and stir for 30 minutes. Add 8 kg of silane coupling agent 3-aminopropyltriethoxysilane and 20 kg of polyacrylic acid with a molecular weight of 3000 and stir for 30 minutes. Heat to 60°C and stir for 3 hours. Cool to room temperature to obtain the initial lithium soapstone-based water-resistant material.

[0051] Step 2: The final lithium soapstone-based water-resistant additive is filtered through a 250-mesh sieve to remove substances that cannot be filtered. The filtered slurry is then collected to obtain the filtered slurry.

[0052] Step 3: Pour the final lithium soapstone-based water-resistant additive into a clean, anhydrous fluoroplastic storage container and seal it for storage.

[0053] The lithium saponite-based water-resistant additive obtained in Example 4 was added to the waterborne acrylic coating. The waterborne acrylic coating without the additive from Example 4 was used as a blank sample. The water resistance of the waterborne acrylic coating sample was tested according to GB / T1733 "Test Method for Water Resistance of Coating Film".

[0054] The addition of lithium saponite-based water-resistant additives suitable for water-based coatings improves the water resistance of acrylic coatings by 300 hours.

[0055] Example 5.

[0056] Step 1: Add 2200 kg of deionized water to a clean reactor equipped with stirring and heating functions, start stirring and add 100 kg of lithium soapstone. After the lithium soapstone is evenly dispersed, add 12 kg of analytical grade cerium nitrate and stir for 30 minutes. Add 10 kg of silane coupling agent N-2-aminoethyl-3-aminopropylmethyldiethoxysilane and 20 kg of polyacrylic acid with a molecular weight of 5000 and stir for 30 minutes. Heat to 80°C and stir for 3 hours. Cool to room temperature to obtain the initial lithium soapstone-based water-resistant material.

[0057] Step 2: The final lithium soapstone-based water-resistant additive is filtered through a 300-mesh sieve to remove substances that cannot be filtered. The filtered slurry is then collected to obtain the filtered slurry.

[0058] Step 3: Pour the final lithium soapstone-based water-resistant additive into a clean, anhydrous fluoroplastic storage container and seal it for storage.

[0059] The lithium saponite-based water-resistant additive obtained in Example 5 was added to the waterborne acrylic coating. The waterborne acrylic coating without the additive from Example 5 was used as a blank sample. The water resistance of the waterborne acrylic coating sample was tested according to GB / T1733 "Test Method for Water Resistance of Coating Film".

[0060] The addition of lithium saponite-based water-resistant additives suitable for water-based coatings improves the water resistance of acrylic coatings by 300 hours.

[0061] Example 6.

[0062] Step 1: Add 3000 kg of deionized water to a clean reactor equipped with stirring and heating functions, start stirring and add 100 kg of lithium soapstone. After the lithium soapstone is evenly dispersed, add 11 kg of chemically pure cerium nitrate and stir for 30 minutes. Add 9 kg of silane coupling agent 3-diethylenetriaminepropyltrimethoxysilane and 20 kg of polyacrylic acid with a molecular weight of 3000 and stir for 30 minutes. Heat to 60°C and stir for 2 hours. Cool to room temperature to obtain the initial lithium soapstone-based water-resistant material.

[0063] Step 2: Filter the slurry through a 200-mesh sieve to remove substances that cannot be filtered out. Collect the filtered slurry to obtain the final lithium soapstone-based water-resistant additive.

[0064] Step 3: Pour the final lithium soapstone-based water-resistant additive into a clean, anhydrous stainless steel storage tank and seal it for storage.

[0065] The lithium saponite-based water-resistant additive obtained in Example 6 was added to the waterborne acrylic coating. The waterborne acrylic coating without the additive from Example 6 was used as a blank sample. The water resistance of the waterborne acrylic coating sample was tested according to GB / T1733 "Test Method for Water Resistance of Coating Film".

[0066] The addition of lithium saponite-based water-resistant additives suitable for water-based coatings improves the water resistance of acrylic coatings by 300 hours.

Claims

1. A lithium saponite-based water-resistant additive suitable for water-based coatings, characterized in that, The additive includes the main ingredient lithium saponite and auxiliary materials; by mass parts, the main ingredient is 100 parts lithium saponite; the auxiliary materials are 2-10 parts cerium nitrate, 5-15 parts silane coupling agent, 5-20 parts polyacrylic acid, and 100-5000 parts deionized water. The preparation process of the lithium saponite-based water-resistant additive suitable for water-based coatings includes the following preparation steps: Step 1: Preparation of initial lithium saponite-based water-resistant additive: Add deionized water to a clean reactor equipped with stirring and heating functions, start stirring and add lithium saponite. After the lithium saponite is evenly dispersed, add cerium nitrate and stir for 30 minutes. Then add silane coupling agent and polyacrylic acid and stir for 30 minutes. Heat to a certain temperature and stir. Cool to room temperature to obtain the initial lithium saponite-based water-resistant additive. Step 2: Preparation of lithium saponite-based water-resistant additive; Step 3: Packing of lithium soapstone-based water-resistant additives.

2. The lithium saponite-based water-resistant additive for water-based coatings according to claim 1, characterized in that, Lithium saponite is a powdered magnesium lithium silicate material; cerium nitrate is chemically pure or analytically pure cerium nitrate hexahydrate; silane coupling agent is a compound with silanoxy and amino groups on its molecule; the molecular weight range of polyacrylic acid is 2000-5000; and the conductivity of deionized water is less than 0.5 mS / cm.

3. A lithium saponite-based water-resistant additive suitable for water-based coatings according to claim 1, characterized in that, The heating temperature is 50-80℃, and the stirring time is 2-4 hours.

4. A lithium saponite-based water-resistant additive suitable for water-based coatings according to claim 1, characterized in that, Step 2 specifically involves filtering the initial lithium saponite-based water-resistant additive through a 100-300 mesh sieve to remove substances that cannot be filtered out, collecting the filtered additive, and obtaining the final lithium saponite-based water-resistant additive.

5. A lithium saponite-based water-resistant additive suitable for water-based coatings according to claim 1, characterized in that, Step 3 specifically involves injecting the final lithium soapstone-based water-resistant additive into a clean, anhydrous storage tank and sealing it for preservation.

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