Ultrafine flaky talcum powder for water-based coatings and preparation method thereof

Abstract

The invention discloses an ultrafine flaky talc powder for water-based coatings and a preparation method thereof. The talc powder is prepared from talc, a silicon-based grinding aid modifier and triethanolamine, wherein the amount of the silicon-based grinding aid modifier and triethanolamine is calculated based on the silicon dioxide content of the talc and the final fineness of the talc powder, the silicon-based grinding aid modifier is 0.1-0.3 wt%, and the triethanolamine is 0.5-1.0 wt%. The ultrafine flaky talc powder for water-based coatings has high purity, controllable fineness, good hydrophilicity, can be quickly dispersed in the water phase without external force, and the dispersed aqueous solution has low viscosity, good fluidity, strong suspension, and high sedimentation volume; after being applied to water-based coatings, the system solves the problems of many bubbles and pinholes, and at the same time improves the construction solid content and storage stability of the coating; plays a good barrier and shielding role, improves weather resistance and light aging resistance; avoids the dusting of ultrafine talc powder, and improves the production environment of water-based coating enterprises.

Description

Technical Field

[0001] The invention relates to the field of water-based coatings, and in particular to ultrafine flaky talcum powder for water-based coatings and a preparation method thereof. Background Art

[0002] With the continuous improvement of people's living standards and environmental awareness, as well as the country's strict restrictions on VOC emissions from coatings, the development and use of pollution-free green coatings is crucial, and the "oil-to-water" coating industry has become inevitable. For example, water-based interior and exterior wall coatings, water-based wood coatings, water-based steel structure coatings, water-based automotive coatings, and water-based anti-corrosion coatings have developed greatly in recent decades.

[0003] Talc is a common filler and modifier in the chemical industry and is widely used in rubber, plastic, coatings and other fields. However, since natural talc has strong hydrophobicity, and the higher the purity and the finer the fineness, the stronger the hydrophobicity, this affects the application effect and filling ratio of talc in water-based coatings.

[0004] Although adding wetting agents, dispersants and other coating additives can improve the compatibility of talcum powder with water, it takes a long time to disperse and consumes a lot of energy. After dispersion, the system has high viscosity and many bubbles, which makes it easy to have problems such as pinholes. In addition, dust is flying around at the production site, which seriously pollutes the production environment. This also limits the application of talcum powder in water-based coatings.

[0005] The research on hydrophilic modification of talc is mainly focused on papermaking and related applications, such as:

[0006] Japanese invention patent application number JP01-131018 discloses a method for treating hydrophobic talc powder with a phosphoric acid series agent. The method is to heat the talc powder at 70°C to 250°C, treat it with phosphoric acid or phosphate, then immediately centrifuge it, wash it with about 20 times the volume of water, and then dry it at 105°C. The hydrophilic talc powder prepared by this method is not hydrophilic enough, and the process is cumbersome, the product cost is high, and it is not suitable for industrial production.

[0007] The Chinese invention patent "A hydrophilic talc and its preparation method" with application number 96106261.4 discloses a method for modifying hydrophobic talc into hydrophilic talc and a hydrophilic talc with small particle size and high hydrophilicity. The technical key points are: placing talc powder in a stirring type pulverizer containing a filling medium, and pulverizing for 4-12 hours. This method directly modifies the hydrophobic talc into hydrophilic talc during the pulverization of talc powder, thereby simplifying the modification process of talc and effectively reducing the cost of hydrophilic talc, but the pulverization and grinding time is long and the production efficiency is low.

[0008] The Chinese invention patent with application number 201210496667.6, "A modified talc for paper coating and its preparation method", discloses a modified talc for paper coating, the main components of which are: natural talc in the form of flake particles with a mass percentage of ≥60%, anionic polyacrylic acid-acrylate-sulfonate copolymer with a mass percentage of 0.3-0.8%, sodium carboxymethyl cellulose with a mass percentage of 0.2-0.5%, industrial grade NaOH with a mass percentage of 0.02-0.1%, and water with a mass percentage of 5.0-10.0%. The modified talc product obtained by the preparation method of the invention has strong hydrophilicity and is easy to disperse in water phase. At the same time, the dispersion of pigments and fillers has low viscosity, good fluidity, stable suspension, and is not easy to precipitate, which can effectively improve the quality of paper. However, the modified talc obtained by this method is actually pre-mixed with water and then pressurized to make talc particles, so that the talc powder achieves a hydrophilic effect, but the application process needs to be crushed into powder by grinding or other mechanical forces, which not only increases the cost but also easily causes agglomeration problems; in addition, the addition of water affects the purity of the talc itself, limits its scope of application, and makes packaging, storage and transportation more difficult.

[0009] The Chinese invention patent "A method for preparing a network gel-modified talcum powder for papermaking" with application number 201510976167.6 discloses a method for preparing a network gel-modified talcum powder for papermaking. It is characterized by a nano-talcum powder with softness formed by interlacing talcum powder, surface modifier and three-dimensional polymer network gel in a weight ratio of 100:1-5:10-20. The modified talcum powder uses extrusion and puffing technology to make the surface modifier penetrate into the layered structure of talcum powder, improve the hydrophilicity and surface activity of talcum powder, and polymerize with flexible monomers under the action of cross-linking agents to form a three-dimensional network polymer gel. The network gel is interlaced in the layered structure of the modified talcum powder, increasing the strength and toughness of the talcum powder, while increasing the active groups on the surface of the modified talcum powder, improving the flexibility and dispersibility of the modified talcum powder, and increasing the binding force between the modified talcum powder and plant fibers. When the modified talc powder of the invention is used in papermaking, it can significantly improve the flexibility of paper, making the paper feel good, light and easy to print. The preparation process of network gel modified talc powder is complicated, the amount of additives is large, the cost is high, and the main purpose is to increase the strength and toughness of talc powder in the papermaking application process, thereby improving the flexibility of paper. It is not suitable for industrial production, and the coating industry is also difficult to accept its high cost.

[0010] Chinese patent application CN109111808A a solar heat-absorbing coating and its preparation method (CN109054474A a special anti-corrosion paint for distribution cabinet shell and its preparation method; CN108912438A a corrosion-resistant flame-retardant cable material and its preparation method; CN108706939A a special insulation material for heating system and its preparation method; CN108530738A a special cable material for computer and its preparation method; CN108485419A a special insulation coating for building exterior wall and its preparation method...) talcum powder, triethanolamine and vinyl tri(β-methoxyethoxy) silane are used to prepare the coating, but it is used to prepare the coating. It is not to modify talcum powder. Talc powder, bentonite, jade powder and boron mud are weighed in a weight ratio of 6:3:2:1 and mixed evenly. 1.5% of triethanolamine, 2% of sodium polyacrylate, 1.5% of calcium lignin sulfonate and 0.6% of vinyl tri(β-methoxyethoxy) silane are added. The mixture is ground at 2000rpm for 15min, dried, crushed and sieved through a 400-mesh sieve. Then, an appropriate amount of water is added to make a slurry with a concentration of 45%. 2% of sodium dodecylbenzene sulfonate, 4% of polyvinyl pyrrolidone, 6% of silicone-acrylic emulsion, 0.5% of diethylene glycol butyl ether and 1.5% of dodecyl alcohol are added. The mixture is stirred for 1.5h, filtered, dried, crushed and sieved through a 400-mesh sieve. The purpose of adding triethanolamine in the coating preparation process is to adjust the pH and prevent acid regurgitation; while silane coupling agents such as vinyl tri(β-methoxyethoxy) silane are used as adhesion promoters (adhesion promoters) for mineral-filled polymers. In the preparation process of water-based coatings, silicon-based grinding aids and triethanolamine are premixed, and then talcum powder is added. The talcum powder and the aqueous solution are in a stratified state, and the talcum powder cannot be wetted by water without external force and dispersed in water, and the slurry viscosity cannot be reduced. Figure 1 shown.

[0011] Therefore, the current existing technology is complicated, the product cost is high, and it is difficult to promote industrial applications; there are many types of agents and a large proportion of additions, which not only has high costs, but also reduces the purity of talcum powder and has a high error rate. Summary of the invention

[0012] The object of the present invention is to provide an ultrafine flaky talc powder for water-based coatings. Through surface coating modification technology and grinding process, the affinity of ultrafine flaky talc powder with water is improved, the compatibility, wettability and dispersibility are improved, the viscosity of the water-based coating system is reduced, the construction solid content and storage stability are increased, and the problems of many bubbles, pinholes and large dust in the preparation and construction process of water-based coatings are solved. At the same time, the flaky talc powder with a large diameter-to-thickness ratio has a good barrier shielding effect, improves the weather resistance and light aging resistance of the coating, and greatly enhances the application value of talc powder in the water-based coating industry.

[0013] To achieve the above-mentioned purpose, the present invention provides an ultrafine flaky talcum powder for water-based coatings, characterized in that it is prepared from three components: talc, a silicon-based grinding aid modifier and triethanolamine, wherein the amounts of the silicon-based grinding aid modifier and the triethanolamine are calculated based on the silicon dioxide content of the talc and the final fineness of the talc, the mass amount of the silicon-based grinding aid modifier is 0.1-0.3%, and the mass amount of the triethanolamine is 0.5-1.0%.

[0014] Furthermore, the mesh size of the talcum powder is 1000 to 3000 meshes.

[0015] Furthermore, the SiO2% content of the talc block is 40-60wt%.

[0016] Furthermore, the silicon-based grinding aid modifier is GR-Z101.

[0017] Further, the method comprises the following preparation steps:

[0018] S1. The raw material talc is crushed so that the diameter of the talc fragments after the initial crushing should be ≤8mm; the crushed material enters the conveyor belt, and enters the soaking tank filled with sodium hydroxide solution through the conveyor belt and soaks for more than 1min. The concentration of the sodium hydroxide solution in the soaking tank is 0.1 to 0.4 mol / L; preferably, the initial crushing is performed by using a jaw crusher, a hammer crusher or a roller crusher to crush the talc powder;

[0019] S2. The soaked material is continuously conveyed by a conveyor belt, and during the conveying process, a silicon-based grinding aid modifier having a mass ratio of 0.1 to 0.3% of talc fragments is sprayed;

[0020] S3 is then transported to a vertical mill with a grading system and ground into 500 to 1000 mesh talc coarse powder;

[0021] S4 is then transported to a peeling airflow grinding bin with a grading system; during the transportation process, 0.5-1.0% triethanolamine of talc coarse powder is sprayed;

[0022] S5 peeling jet mill with grading system continues to grind and classify 1000-3000 mesh ultra-fine talc powder, which is transported to the finished product warehouse;

[0023] S6. Finally, weigh and package to obtain the ultra-fine flaky talc product for water-based coatings.

[0024] The diameter φ of the talc fragments after primary crushing by the jaw crusher (or hammer crusher or roller crusher) of the present invention should be ≤8mm. When the diameter φ of the talc fragments after primary crushing is ≤8mm, the soaking effect in the soaking tank will be better.

[0025] The concentration of the sodium hydroxide solution in the soaking tank of the present invention should be controlled at 0.1-0.4 mol / L, and the residence time of the talc fragments in the soaking tank should be ≥1 min. The purpose of this step is to perform hydroxylation pretreatment on the surface of the talc so that the surface of the talc has more reactive groups to prepare for subsequent surface modification. The difficulty lies in the control of the concentration of the sodium hydroxide solution and the soaking time. The sodium hydroxide solution in the soaking tank should be replenished in real time, and the concentration should be detected every 0.5 h to ensure that it is controlled at 0.1-0.4 mol / L. Too high will affect the pH value of talc, and too low will not be effective.

[0026] The mass ratio of the silicon-based grinding aid modifier GR-Z101 sprayed by the spray device of the present invention should be controlled at 0.1-0.3% of the talc fragments according to the final fineness of the talc powder. The silicon-based grinding aid modifier GR-Z101 can effectively improve the grinding efficiency and reduce the production energy consumption. At the same time, the talc powder modified by the additive has a certain hydrophilicity. The proportion of the additive should be determined according to the final fineness of the talc powder. The finer the powder, the higher the proportion of the additive. Specifically, when the talc powder is 1000 mesh, the amount of the silicon-based grinding aid modifier is 0.1%, when the talc powder is 1250 mesh-1500 mesh, the amount of the silicon-based grinding aid modifier is 0.15%, when the talc powder is 2000 mesh, the amount of the silicon-based grinding aid modifier is 0.2%, when the talc powder is 2500 mesh, the amount of the silicon-based grinding aid modifier is 0.25%, and when the talc powder is 3000 mesh, the amount of the silicon-based grinding aid modifier is 0.3%. In addition, the additives with grinding aid effect are selected here. Compared with conventional surface modifiers, one surface modification equipment can be reduced in the process, the process is simplified, and the cost is further reduced.

[0027] The mass ratio of triethanolamine sprayed by the spray device of the present invention should be controlled to be 0.5-1.0% of the coarse talc powder according to the silicon dioxide content of the talc block and the final fineness of the talc powder. The addition ratio of triethanolamine should be determined according to the silicon dioxide content of the talc block and the final fineness of the talc powder. The higher the silicon dioxide content of the talc block, the higher the addition ratio of triethanolamine; the finer the final fineness of the talc powder, the higher the addition ratio of triethanolamine.

[0028] Specifically, when the silicon dioxide content of the talc block is 40-45%, if the final fineness of the talc powder is between 1000 and 1250 meshes, the addition ratio of triethanolamine is 0.50% of the coarse talc powder; if the final fineness of the talc powder is 1500 meshes, the addition ratio of triethanolamine is 0.60% of the coarse talc powder; if the final fineness of the talc powder is 2000 meshes, the addition ratio of triethanolamine is 0.65% of the coarse talc powder; if the final fineness of the talc powder is 2500 meshes, the addition ratio of triethanolamine is 0.75% of the coarse talc powder; if the final fineness of the talc powder is 3000 meshes, the addition ratio of triethanolamine is 0.80% of the coarse talc powder.

[0029] When the silicon dioxide content of the talc block is 48-53%, if the final fineness of the talc powder is between 1000 and 1250 meshes, the addition ratio of triethanolamine is 0.60% of the coarse talc powder; when the final fineness of the talc powder is 1500 meshes, the addition ratio of triethanolamine is 0.70% of the coarse talc powder; when the final fineness of the talc powder is 2000 meshes, the addition ratio of triethanolamine is 0.75% of the coarse talc powder; when the final fineness of the talc powder is 2500 meshes, the addition ratio of triethanolamine is 0.85% of the coarse talc powder; when the final fineness of the talc powder is 3000 meshes, the addition ratio of triethanolamine is 0.90% of the coarse talc powder.

[0030] When the silicon dioxide content of the talc block is 55-60%, if the final fineness of the talc powder is between 1000 and 1250 meshes, the addition ratio of triethanolamine is 0.70% of the coarse talc powder; when the final fineness of the talc powder is 1500 meshes, the addition ratio of triethanolamine is 0.80% of the coarse talc powder; when the final fineness of the talc powder is 2000 meshes, the addition ratio of triethanolamine is 0.85% of the coarse talc powder; when the final fineness of the talc powder is 2500 meshes, the addition ratio of triethanolamine is 0.95% of the coarse talc powder; when the final fineness of the talc powder is 3000 meshes, the addition ratio of triethanolamine is 1.00% of the coarse talc powder.

[0031] The talc powder ground by the combined action of the flaking jet mill and the secondary classifier of the present invention can be specified to any fineness within the range of 1000-3000 meshes; the flaking jet mill can retain the flaky structure of the talc powder itself to the maximum extent, so that it has a larger diameter-thickness ratio, and can play a good barrier and shielding role in water-based coatings such as steel structure paint and automobile paint, and improve weather resistance and light aging resistance. The flaking jet mill can retain the flaky structure of the talc powder itself to the maximum extent, so that the talc powder has a larger diameter-thickness ratio, paves the way for subsequent applications, and improves the added value of the talc powder.

[0032] The traditional processing technology of multi-pass modification of the present invention requires multiple powder surface modification equipment, which has many equipment, complex process, low efficiency, high energy consumption and high processing cost. The present invention sets a soaking tank and a spray device during the conveying process between the jaw crusher (or hammer crusher or roller crusher) and the vertical mill, and sets a spray device during the conveying process between the vertical mill and the flaking airflow mill, thereby reducing the processing energy consumption many times.

[0033] The present invention improves the hydrophilicity of talcum powder through surface coating modification technology, further solves the problems of poor compatibility and dispersibility, high viscosity, many bubbles, pinholes and the like in the application process of talcum powder in water-based paint, and can also improve the construction solid content and storage stability of the paint, avoid the dusting of ultrafine talcum powder, and improve the production environment of water-based paint enterprises.

[0034] At the same time, the present invention retains the flaky structure of talcum powder to the maximum extent through a special grinding process, so that it has a larger diameter-to-thickness ratio, can play a good barrier and shielding role in coatings such as steel structure paint and automobile paint, and improves weather resistance and light aging resistance.

[0035] Compared with the prior art, the preparation method of the present invention obtains ultrafine flaky talcum powder suitable for water-based coatings. The talcum powder has high purity, controllable fineness, and good hydrophilicity. It can be quickly dispersed in the water phase without the action of external force, and the dispersed aqueous solution has low viscosity, good fluidity, strong suspension, and high sedimentation volume. After being applied to water-based coatings, the problems of many bubbles and pinholes in the system are solved, and at the same time, the construction solid content and storage stability of the coating are improved, and it can also play a good barrier and shielding role, improve weather resistance and light aging resistance; in addition, the dusting of ultrafine talcum powder is avoided, and the production environment of water-based coating enterprises is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a comparison chart of background technology.

[0037] Figure 2 This is a process flow chart for preparing ultrafine flaky talc powder for water-based coatings.

[0038] Figure 3 2 are contact angle diagrams of talcum powder products and water, wherein the left one is the contact angle diagram of the ultrafine flaky talcum powder product for water-based coatings in Example 1 and water, and the right one is the contact angle diagram of the talcum powder of the comparative example and water.

[0039] Figure 4 This is a rendering of the ultrafine flaky talc powder product for water-based coatings in Example 1 being directly wetted and dispersed in water without external force.

[0040] Figure 5 Scanning electron micrograph of ultrafine flaky talc used in waterborne coatings.

[0041] Figure 6 Infrared absorption spectrum of ultrafine flaky talc used in water-based coatings. DETAILED DESCRIPTION

[0042] Embodiments of the present invention are described in detail below, and the examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by reference to the accompanying drawings are exemplary, are intended to be used to explain the present invention, and are not to be construed as limitations of the present invention. Those who do not indicate specific techniques or conditions in the embodiments are carried out according to the techniques or conditions described in the documents in this area or according to the product specification. Those who do not indicate the manufacturer of reagents or instruments used are all conventional products that can be obtained commercially.

[0043] Contact angle θ: The contact angle refers to the angle between the solid-liquid interface through the liquid interior to the gas-liquid interface at the junction of solid, liquid and gas phases.

[0044] If θ is less than 90°, the solid surface is hydrophilic, that is, the liquid can wet the solid more easily, and the smaller the angle is, the better the wettability is; if θ is greater than 90°, the solid surface is hydrophobic, that is, the liquid cannot wet the solid easily and can move easily on the surface.

[0045] ①When θ=0°, complete wetting;

[0046] ②When θ<90°, partial wetting or wetting;

[0047] ③When θ=90°, it is the dividing line between wetting and non-wetting;

[0048] ④When θ>90°, no wetting;

[0049] ⑤When θ=180°, there is no wetting at all.

[0050] The silicon-based grinding aid modifier GR-Z101 added in the present invention can not only transform the surface of the talc coarse powder from hydrophobic to hydrophilic, but also play a steric hindrance role, eliminate the secondary agglomeration of the powder from the source kinetic energy, and achieve the purpose of grinding aid and energy saving;

[0051] The invention grinds the talc coarse powder after spraying triethanolamine into talc powder with a specified fineness under the combined action of a flaking airflow mill and a secondary classifier; during the grinding process, the surface energy of the talc powder is the strongest, and at this time, the triethanolamine can be evenly coated on the surface of the talc powder to achieve the purpose of surface coating modification; at the same time, the flaking airflow mill can retain the flaky structure of the talc powder itself to the maximum extent.

[0052] Embodiment 1:

[0053] Combination Figure 2 The process flow chart of preparing ultrafine flaky talc powder for water-based coatings is presented.

[0054] Raw materials: blocky talc with complete flake structure and 58-60% silica content.

[0055] step:

[0056] S1. First, the blocky talc raw material is crushed by a jaw or hammer crusher to a diameter of φ≤8mm, and the crushed material enters a conveyor belt, and then enters a soaking tank filled with sodium hydroxide solution through the conveyor belt and soaks for more than 1 minute. The concentration of the sodium hydroxide solution in the soaking tank is 0.1-0.4 mol / L;

[0057] S2. The soaked material is continuously conveyed by a conveyor belt, and during the conveying process, a silicon-based grinding aid modifier GR-Z101 with a mass ratio of 0.15% of talc fragments is sprayed;

[0058] S3 is then transported to a vertical mill with a grading system and ground into a 600 mesh talc powder;

[0059] S4 is then transported to a peeling airflow grinding bin with a grading system; during the transportation process, 0.75% triethanolamine of talc coarse powder is sprayed;

[0060] S5 peeling jet mill with grading system continues grinding and grades out 1250 mesh ultra-fine talc powder, which is transported to the finished product warehouse;

[0061] S6. Finally, weigh and package to obtain the ultra-fine flaky talc product for water-based coatings.

[0062] The whiteness of the ultra-fine flaky talc powder product used for water-based coatings was measured to be 91.80°, the hue L value was 81.10, the a value was -0.16, the b value was 4.43, and the median particle size D 50 The diameter of the ultrafine flaky talc powder used in water-based coatings is 6.393 μm, the ignition loss is 7.22%, the pH value is 9.46, and the contact angles of the ultrafine flaky talc powder products with water are: the left contact angle is 67.36°, the right contact angle is 76.93°, and the average contact angle is 72.15°. For details, see Figure 3 A, contact angle 0<90°, that is, when the ultrafine flaky talc powder of water-based paint comes into contact with water, it can be wetted and dispersed in the water, thus solving the dust problem of ultrafine talc powder in the processing of water-based paint. The ultrafine flaky talc powder product used for water-based paint has a T-4 cup gravity viscosity of 21s when the solid content in the aqueous phase dispersion is 40%, and a Stormo viscosity of 69.1KU when the filling ratio of water-based steel structure primer is 20%, and the rotational viscosity is 1201mPa·s. It is diluted to the construction viscosity with 15% water, and the gravity viscosity is 33s. The ultrafine flaky talc powder of water-based paint is directly wetted and dispersed in water without external force, achieving the effect of dust-free coating industry, such as Figure 4 The scanning electron microscope image of ultrafine flaky talc powder used in water-based coatings is shown in Figure 5 , infrared absorption spectrum is shown in Figure 6 It can be seen that the ultrafine flaky talc powder of the water-based coating prepared in this embodiment of the present invention is composed of three substances: talc, silicon-based grinding aid modifier, and triethanolamine.

[0063] Embodiment 2:

[0064] Combination Figure 2 The process flow chart of preparing ultrafine flaky talc powder for water-based coatings is presented.

[0065] Raw materials: blocky talc with complete flake structure and silicon dioxide content of 40-42%.

[0066] step:

[0067] S1. First, the blocky talc raw material is crushed into a diameter of φ≤8mm by a jaw or hammer crusher. The crushed material enters a conveyor belt and then enters a soaking pool filled with sodium hydroxide solution through the conveyor belt for soaking for more than 1 minute. The concentration of the sodium hydroxide solution in the soaking pool is 0.1-0.4 mol / L.

[0068] S2. The soaked material is continuously conveyed by the conveyor belt, and during the conveying process, the silicon-based grinding aid modifier GR-Z101 with a mass ratio of 0.15% of talc fragments is sprayed.

[0069] S3. Then transport it to a vertical mill with a grading system and grind it into 600 mesh talc coarse powder.

[0070] S4 is then transported to a peeling airflow grinding bin with a grading system; during the transportation process, 0.5% triethanolamine with a mass ratio of talc coarse powder is sprayed.

[0071] The S5 flaking jet mill with a grading system continues to grind and classify the 1250 mesh ultra-fine talc powder, which is transported to the finished product warehouse.

[0072] S6. Finally, weigh and package to obtain the ultra-fine flaky talc product for water-based coatings.

[0073] The whiteness of the ultra-fine flaky talc powder product used for water-based coatings was measured to be 90.62°, the hue L value was 80.23, the a value was -0.08, the b value was 4.47, and the median particle size D 50 The particle size is 6.285μm, the ignition loss is 21.79%, the pH value is 9.52, and the contact angles of the ultrafine flaky talc products used in water-based coatings with water are: left contact angle 65.26°, right contact angle 72.37°, and average contact angle 68.82°. The T-4 cup gravity viscosity of the ultrafine flaky talc products used in water-based coatings is 19s when the solid content in the aqueous phase dispersion is 40%, and the Stormo viscosity is 63.4KU when the filling ratio of the water-based steel structure primer is 20%, the rotation viscosity is 1078mPa·s, and the gravity viscosity is 30s when diluted to the construction viscosity with 15% water.

[0074] Embodiment 3:

[0075] Combination Figure 2 The process flow chart of preparing ultrafine flaky talc powder for water-based coatings is presented.

[0076] Raw materials: blocky talc with complete flake structure and silica content of 49-51%.

[0077] step:

[0078] S1. First, the blocky talc raw material is crushed into a diameter of φ≤8mm by a jaw or hammer crusher. The crushed material enters a conveyor belt and then enters a soaking pool filled with sodium hydroxide solution through the conveyor belt for soaking for more than 1 minute. The concentration of the sodium hydroxide solution in the soaking pool is 0.1-0.4 mol / L.

[0079] S2. The soaked material is continuously conveyed by the conveyor belt, and during the conveying process, the silicon-based grinding aid modifier GR-Z101 with a mass ratio of 0.15% of talc fragments is sprayed.

[0080] S3. Then transport it to a vertical mill with a grading system and grind it into 600 mesh talc coarse powder.

[0081] S4 is then transported to a peeling airflow grinding bin with a grading system; during the transportation process, 0.6% triethanolamine with a mass ratio of talc coarse powder is sprayed.

[0082] The S5 flaking jet mill with a grading system continues to grind and classify the 1250 mesh ultra-fine talc powder, which is transported to the finished product warehouse.

[0083] S6. Finally, weigh and package to obtain the ultra-fine flaky talc product for water-based coatings.

[0084] The whiteness of the ultra-fine flaky talc powder product used for water-based coatings was measured to be 91.27°, the hue L value was 80.86, the a value was -0.22, the b value was 4.38, and the median particle size D 50 The particle size is 6.277μm, the ignition loss is 15.33%, the pH value is 9.46, and the contact angles of the ultrafine flaky talc products used for water-based coatings with water are: left contact angle 66.42°, right contact angle 74.28°, and average contact angle 70.35°. The T-4 cup gravity viscosity of the ultrafine flaky talc products used for water-based coatings is 20s when the solid content in the aqueous phase dispersion is 40%, and the Stormo viscosity is 67.6KU when the filling ratio of the water-based steel structure primer is 20%, the rotation viscosity is 1172mPa·s, and the gravity viscosity is 32s when diluted to the construction viscosity with 15% water.

[0085] Embodiment 4:

[0086] Combination Figure 2 The process flow chart of preparing ultrafine flaky talc powder for water-based coatings is presented.

[0087] Raw materials: blocky talc with complete flake structure and 58-60% silica content.

[0088] step:

[0089] S1. First, the blocky talc raw material is crushed by a jaw or hammer crusher to a diameter of φ≤8mm, and the crushed material enters a conveyor belt, and then enters a soaking tank filled with sodium hydroxide solution through the conveyor belt and soaks for more than 1 minute. The concentration of the sodium hydroxide solution in the soaking tank is 0.1-0.4 mol / L;

[0090] S2. The soaked material is continuously conveyed by a conveyor belt, and during the conveying process, a silicon-based grinding aid modifier GR-Z101 with a mass ratio of 0.10% of talc fragments is sprayed;

[0091] S3 is then transported to a vertical mill with a grading system and ground into a 600 mesh talc powder;

[0092] S4 is then transported to a peeling airflow grinding bin with a grading system; during the transportation process, 0.7% triethanolamine of talc coarse powder is sprayed;

[0093] S5 peeling jet mill with grading system continues to grind and classify 1000 mesh ultra-fine talc powder, which is transported to the finished product warehouse;

[0094] S6. Finally, weigh and package to obtain the ultra-fine flaky talc product for water-based coatings.

[0095] The whiteness of the ultrafine flaky talc powder product used for water-based coatings was measured to be 91.64°, the hue L value was 81.04, the a value was -0.16, the b value was 4.36, and the median particle size D 50 The particle size is 7.682μm, the ignition loss is 7.25%, the pH value is 9.40, and the contact angles of the ultrafine flaky talc products used for water-based coatings with water are: left contact angle 66.28°, right contact angle 72.33°, and average contact angle 69.31°. The T-4 cup gravity viscosity of the ultrafine flaky talc products used for water-based coatings is 20s when the solid content in the aqueous phase dispersion is 40%, and the Stormo viscosity is 66.9KU when the filling ratio of the water-based steel structure primer is 20%, the rotation viscosity is 1141mPa·s, and the gravity viscosity is 31s when diluted to the construction viscosity with 15% water.

[0096] Embodiment 5:

[0097] Combination Figure 2 The process flow chart of preparing ultrafine flaky talc powder for water-based coatings is presented.

[0098] Raw materials: blocky talc with complete flake structure and 58-60% silica content.

[0099] step:

[0100] S1. First, the blocky talc raw material is crushed into a diameter of φ≤8mm by a jaw or hammer crusher. The crushed material enters a conveyor belt and then enters a soaking pool filled with sodium hydroxide solution through the conveyor belt for soaking for more than 1 minute. The concentration of the sodium hydroxide solution in the soaking pool is 0.1-0.4 mol / L.

[0101] S2. The soaked material is continuously conveyed by the conveyor belt, and during the conveying process, the silicon-based grinding aid modifier GR-Z101 with a mass ratio of 0.30% of talc fragments is sprayed.

[0102] S3. Then transport it to a vertical mill with a grading system and grind it into 1000 mesh talc coarse powder.

[0103] S4 is then transported to a peeling airflow grinding bin with a grading system; during the transportation process, 1.0% triethanolamine with a mass ratio of talc coarse powder is sprayed.

[0104] S5 peeling jet mill with grading system continues to grind and classify 3000 mesh ultra-fine talc powder, which is transported to the finished product warehouse.

[0105] S6. Finally, weigh and package to obtain the ultra-fine flaky talc product for water-based coatings.

[0106] The whiteness of the ultrafine flaky talc powder used in water-based coatings was 93.61°, the hue L value was 82.90, the a value was 0.07, the b value was 4.62, and the median particle size D 50 The particle size is 4.146μm, the ignition loss is 7.15%, the pH value is 9.54, and the contact angles of the ultra-fine flaky talc products used in water-based coatings with water are: left contact angle 71.66°, right contact angle 78.24°, and average contact angle 74.95°. The T-4 cup gravity viscosity of the ultra-fine flaky talc products used in water-based coatings is 52s when the solid content in the aqueous phase dispersion is 40%, and the Stormo viscosity is 74.6KU when the filling ratio of the water-based steel structure primer is 20%, the rotation viscosity is 1309mPa·s, and the gravity viscosity is 38s when diluted to the construction viscosity with 15% water.

[0107] Comparative Example 1 (without sodium hydroxide solution immersion and spraying of silicon-based grinding aid modifier GR-Z101 and triethanolamine):

[0108] Raw materials: Same as Example 1. Block talc with complete flake structure and 58-60% silicon dioxide content.

[0109] step:

[0110] S1. First, crush the blocky talc raw material into a diameter of φ≤8mm by a jaw or hammer crusher.

[0111] S2. Then it is transported to a vertical mill with a grading system and ground into 600 mesh talc coarse powder.

[0112] Then it is transported to the peeling airflow mill with a grading system for further grinding, and 1250 mesh ultra-fine talcum powder is graded and transported to the finished product warehouse.

[0113] S6. Finally, weigh and package to obtain the talcum powder product.

[0114] The whiteness of the talcum powder product was measured to be 91.77°, the hue L value was 81.16, the a value was -0.14, the b value was 4.15, and the median particle size was D 50 The contact angle of talcum powder product with water is 6.291μm, the loss on ignition is 6.47%, and the pH value is 9.26. The contact angle of talcum powder product with water is: left contact angle 116.44°, right contact angle 124.56°, and the average contact angle is 120.50°. Figure 3 B. The T-4 cup gravity viscosity of the talcum powder product in the aqueous dispersion with a solid content of 40% is 36s, the Stormo viscosity is 81.2KU when the filling ratio of the water-based steel structure primer is 20%, the rotation viscosity is 1661mPa·s, and the gravity viscosity is 52s when diluted with 15% water to the construction viscosity.

[0115] Comparative Example 2:

[0116] Raw materials: Same as Example 2. Block talc with complete flake structure and 40-42% silicon dioxide content.

[0117] step:

[0118] S1. First, crush the blocky talc raw material into a diameter of φ≤8mm by a jaw or hammer crusher.

[0119] S2. Then it is transported to a vertical mill with a grading system and ground into 600 mesh talc coarse powder.

[0120] Then it is transported to the peeling airflow mill with a grading system for further grinding, and 1250 mesh ultra-fine talcum powder is graded and transported to the finished product warehouse.

[0121] S6. Finally, weigh and package to obtain the talcum powder product.

[0122] The whiteness of the talcum powder product was measured to be 90.87°, the hue L value was 80.16, the a value was 0.11, the b value was 4.28, and the median particle size D 5oThe diameter of the talc powder product is 6.276μm, the ignition loss is 20.67%, and the pH value is 9.17. The contact angles of the talc powder product with water are: the left contact angle is 112.61°, the right contact angle is 119.55°, and the average contact angle is 116.08°. The T-4 cup gravity viscosity of the talc powder product in the aqueous dispersion is 31s when the solid content is 40%, the Stormo viscosity is 74.3KU when the filling ratio of the water-based steel structure primer is 20%, the rotation viscosity is 1462mPa·s, and the gravity viscosity is 42s when diluted with 15% water to the construction viscosity.

[0123] Comparative Example 3:

[0124] Raw materials: Same as in Example 3. Block talc with complete flake structure and 49-51% silicon dioxide content.

[0125] step:

[0126] S1. First, crush the blocky talc raw material into a diameter of φ≤8mm by a jaw or hammer crusher.

[0127] S2. Then it is transported to a vertical mill with a grading system and ground into 600 mesh talc coarse powder.

[0128] Then it is transported to the peeling airflow mill with a grading system for further grinding, and 1250 mesh ultra-fine talcum powder is graded and transported to the finished product warehouse.

[0129] S6. Finally, weigh and package to obtain the talcum powder product.

[0130] The whiteness of the talcum powder product was measured to be 91.58°, the hue L value was 81.11, the a value was -0.22, the b value was 4.43, and the median particle size was D 50 The diameter of the talc powder product is 6.258μm, the ignition loss is 14.85%, and the pH value is 9.23. The contact angles of the talc powder product with water are: the left contact angle is 115.17°, the right contact angle is 123.32°, and the average contact angle is 119.25°. The T-4 cup gravity viscosity of the talc powder product in the aqueous dispersion is 34s when the solid content is 40%, the Stormo viscosity is 78.8KU when the filling ratio of the water-based steel structure primer is 20%, the rotational viscosity is 1583mPa·s, and the gravity viscosity is 49s when diluted with 15% water to the construction viscosity.

[0131] Comparative Example 4:

[0132] Raw materials: Same as Example 4. Block talc with complete flake structure and 58-60% silicon dioxide content.

[0133] step:

[0134] S1. First, crush the blocky talc raw material into a diameter of φ≤8mm by a jaw or hammer crusher.

[0135] S2. Then it is transported to a vertical mill with a grading system and ground into 600 mesh talc coarse powder.

[0136] Then it is transported to the peeling airflow mill with a grading system for further grinding, and 1000 mesh ultra-fine talcum powder is graded and transported to the finished product warehouse.

[0137] S6. Finally, weigh and package to obtain the talcum powder product.

[0138] The whiteness of the talcum powder product was measured to be 91.71°, the hue L value was 81.12, the a value was -0.16, the b value was 4.23, and the median particle size D 5o The diameter of the talc powder product is 7.706μm, the ignition loss is 6.67%, and the pH value is 9.20. The contact angles of the talc powder product with water are: the left contact angle is 113.78°, the right contact angle is 122.33°, and the average contact angle is 118.06°. The T-4 cup gravity viscosity of the talc powder product in the aqueous dispersion is 34s when the solid content is 40%, the Stormo viscosity is 78.9KU when the filling ratio of the water-based steel structure primer is 20%, the rotation viscosity is 1592mPa·s, and the gravity viscosity is 50s when diluted with 15% water to the construction viscosity.

[0139] Comparative Example 5:

[0140] Raw materials: Same as Example 5. Block talc with complete flake structure and 58-60% silicon dioxide content.

[0141] step:

[0142] S1. First, crush the blocky talc raw material into a diameter of φ≤8mm by a jaw or hammer crusher.

[0143] S2. Then it is transported to a vertical mill with a grading system and ground into 1000 mesh talc coarse powder.

[0144] Then it is transported to the peeling airflow mill with a grading system for further grinding, and 3000 mesh ultra-fine talcum powder is graded and transported to the finished product warehouse.

[0145] S6. Finally, weigh and package to obtain the talcum powder product.

[0146] The whiteness of the talcum powder product was measured to be 94.07°, the hue L value was 83.26, the a value was 0.25, the b value was 4.38, and the median particle size D 50The surface roughness is 4.060μm, the ignition loss is 6.72%, and the pH value is 9.30. The contact angles of talcum powder products with water are: left contact angle 131.11°, right contact angle 128.67°, and average contact angle 129.89°. The T-4 cup gravity viscosity of talcum powder products in the aqueous dispersion with a solid content of 40% is 96s, the Stormo viscosity is 92.5KU when the filling ratio of water-based steel structure primer is 20%, the rotational viscosity is 1874mPa·s, and the gravity viscosity is 62s when diluted to the construction viscosity with 15% water.

[0147] By comparing Example 1 with Comparative Example 1, Example 2 with Comparative Example 2, Example 3 with Comparative Example 3, and Example 4 with Comparative Example 4, it can be seen that the ultrafine flaky talc products for water-based coatings prepared by the method of the present invention and the method of the comparative example have no difference in whiteness, hue, and fineness. The pH value and loss on ignition of the ultrafine flaky talc products for water-based coatings prepared by the method of the present invention are slightly higher than those of the products prepared in the comparative example; the contact angles are very different, indicating that the ultrafine flaky talc for water-based coatings prepared by the present invention are significantly improved in water compatibility, wettability, and dispersibility; at the same time, the ultrafine flaky talc for water-based coatings prepared by the present invention has a large viscosity reduction in water and water-based coatings, which can reduce the amount of additives such as wetting agents, dispersants, and defoaming agents added, while effectively increasing the construction solid content, and the suspension stability is also greatly improved, having good economic value, and also solving the problem of ultrafine talc dusting, and improving the production environment of coating companies.

[0148] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. An ultrafine flaky talcum powder for water-based coatings, characterized in that: The invention is prepared from three ingredients: talc, silicon-based grinding aid modifier and triethanolamine, and comprises the following preparation steps: S1. The raw material talc is crushed so that the diameter of the talc fragments after the initial crushing should be ≤8mm, and the silicon dioxide content of the talc is 40 wt% to 60 wt%; the crushed material enters the conveyor belt, and enters the soaking tank filled with sodium hydroxide solution through the conveyor belt and soaks for more than 1 minute. The concentration of the sodium hydroxide solution in the soaking tank is 0.1 to 0.4 mol / L; S2. The soaked material is continuously conveyed by a conveyor belt, and during the conveying process, a silicon-based grinding aid modifier having a mass ratio of 0.1% to 0.3% of talc fragments is sprayed, wherein the silicon-based grinding aid modifier model is GR-Z101; S3 is then transported to a vertical mill with a grading system and ground into 500 to 1000 mesh talc coarse powder; S4 is then transported to a peeling airflow grinding bin with a grading system; during the transportation process, 0.5% to 1.0% triethanolamine of the mass ratio of talc coarse powder is sprayed; S5 The peeling jet mill with a grading system continues to grind and classify the ultra-fine talc powder of 1000-3000 mesh and transport it to the finished product warehouse; S6. Finally, the ultrafine flaky talc product for water-based coatings can be obtained by weighing and packaging; Among them, the amount of silicon-based grinding aid modifier and triethanolamine is calculated as follows: When the talc powder is 1000 mesh, the amount of silicon-based grinding aid modifier is 0.1%, when it is 1250-1500 mesh, the amount of silicon-based grinding aid modifier is 0.15%, when it is 2000 mesh, the amount of silicon-based grinding aid modifier is 0.2%, when it is 2500 mesh, the amount of silicon-based grinding aid modifier is 0.25%, when it is 3000 mesh, the amount of silicon-based grinding aid modifier is 0.3%; When the silicon dioxide content of the talc block is 40wt%-45wt%, if the final fineness of the talc powder is 1000-1250 mesh, the addition ratio of triethanolamine is 0.50% of the talc coarse powder; the final fineness of the talc powder is 1500 mesh, the addition ratio of triethanolamine is 0.60% of the talc coarse powder; the final fineness of the talc powder is 2000 mesh, the addition ratio of triethanolamine is 0.65% of the talc coarse powder; the final fineness of the talc powder is 2500 mesh, the addition ratio of triethanolamine is 0.75% of the talc coarse powder; the final fineness of the talc powder is 3000 mesh, and the addition ratio of triethanolamine is 0.80% of the talc coarse powder; When the silicon dioxide content of the talc block is 48wt%-53wt%, if the final fineness of the talc powder is 1000-1250 mesh, the addition ratio of triethanolamine is 0.60% of the talc coarse powder; the final fineness of the talc powder is 1500 mesh, the addition ratio of triethanolamine is 0.70% of the talc coarse powder; the final fineness of the talc powder is 2000 mesh, the addition ratio of triethanolamine is 0.75% of the talc coarse powder; the final fineness of the talc powder is 2500 mesh, the addition ratio of triethanolamine is 0.85% of the talc coarse powder; the final fineness of the talc powder is 3000 mesh, and the addition ratio of triethanolamine is 0.90% of the talc coarse powder; When the silicon dioxide content of the talc block is 55wt%-60wt%, if the final fineness of the talc powder is between 1000 and 1250 meshes, the addition ratio of triethanolamine is 0.70% of the talc coarse powder; the final fineness of the talc powder is 1500 meshes, the addition ratio of triethanolamine is 0.80% of the talc coarse powder; the final fineness of the talc powder is 2000 meshes, the addition ratio of triethanolamine is 0.85% of the talc coarse powder; the final fineness of the talc powder is 2500 meshes, the addition ratio of triethanolamine is 0.95% of the talc coarse powder; the final fineness of the talc powder is 3000 meshes, and the addition ratio of triethanolamine is 1.00% of the talc coarse powder.

2. The ultrafine flaky talcum powder for water-based coatings according to claim 1, characterized in that: The primary crushing is to use a jaw crusher, a hammer crusher or a roller crusher to crush the talc blocks.

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