Difunctional filler, preparation method thereof and coating compound system

Abstract

The invention belongs to the technical field of paint pigments and fillers, and particularly discloses a difunctional filler for improving corrosion resistance and wear resistance of a paint and a preparation method of the difunctional filler. The filler takes silicon carbide particles as a core body, and the surface of the core body is coated with a zinc phosphate compound to form a core-shell structure. The preparation method comprises the following steps: mixing and dispersing a soluble zinc salt solution and silicon carbide particles, and reacting with phosphate to generate the zinc phosphate coating layer. The difunctional filler is suitable for cathode electrophoretic paint, industrial anticorrosive paint and other systems, overcomes the defect of single filler function in the prior art, can significantly improve the wear resistance and corrosion resistance of a coating, and has important application prospects in the field of super-wear-resistant and heavy-duty anticorrosive paint.

Description

Technical Field

[0001] This invention belongs to the field of coating pigments and fillers technology, and specifically relates to a functional filler for coatings. Background Technology

[0002] In the automotive manufacturing and construction machinery industries, the requirements for the surface protection performance of metal components are increasingly stringent. Cathodic electrophoretic coatings are widely used in the primer field due to their advantages such as good uniformity and excellent corrosion resistance. However, with increasing pressure to control costs, more and more companies are seeking a "one-coating process," that is, achieving multiple properties such as corrosion resistance, weather resistance, and wear resistance with only one electrophoretic coating.

[0003] The inventors discovered that traditional methods for improving the overall performance of coatings mainly fall into two categories: First, chemical modification of the resin matrix, such as introducing fluorine-containing functional groups or flexible rubber segments. These methods often suffer from complex reaction conditions, high costs, and poor compatibility between resin synthesis and coating formulation. Second, adding functional inorganic fillers, such as talc, zinc oxide, and calcium carbonate. This method offers advantages such as simple processes and low costs, making it suitable for large-scale industrial applications. However, currently widely used inorganic fillers are mostly single-function, making it difficult to achieve comprehensive performance improvements. Directly blending different types of fillers can easily lead to performance degradation due to agglomeration and interfacial incompatibility. Therefore, developing a composite inorganic filler with synergistic structure and both corrosion resistance and wear resistance is crucial for improving the overall performance of electrophoretic coatings. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a bifunctional filler that improves the corrosion resistance and wear resistance of coatings. The method uses silicon carbide particles as the wear-resistant core and loads zinc phosphate on the surface to provide corrosion resistance. The process is simple and the raw materials are inexpensive and readily available.

[0005] This invention uses silicon carbide particles as the core material and coats their surface with a zinc-phosphorus compound through a wet deposition reaction to form a core-shell structure. This composite structure combines the high hardness of silicon carbide with the corrosion-inhibiting properties of zinc-phosphorus compounds, significantly improving the wear resistance and corrosion resistance of the electrophoretic coating.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of this invention provides a method for preparing a bifunctional filler that improves the corrosion resistance and wear resistance of coatings, comprising the following steps:

[0008] S1. Add soluble zinc salt to deionized water and stir until completely dissolved; then add silicon carbide particles, and after crushing and stirring, disperse the particles evenly.

[0009] S2. Add a soluble phosphate aqueous solution to the suspension system obtained in step S1, and allow it to react completely under stirring.

[0010] S3. After separating, washing and drying the mixture obtained in step S2, a bifunctional filler that improves the anti-corrosion and wear resistance of the coating is obtained.

[0011] The molar concentration of the soluble zinc salt is 0.1~1 mol / L;

[0012] The mass ratio of the silicon carbide particles to the soluble zinc salt is 1~10:1;

[0013] The molar ratio of the soluble phosphate to the soluble zinc salt is 0.5 to 2:1.

[0014] The soluble zinc salt is one or more of ZnCl2, ZnSO4, or Zn(NO3)2; the soluble phosphate is one or more of Na3PO4, K3PO4, or (NH4)3PO4.

[0015] The silicon carbide particles have a particle size of 0.05~10μm.

[0016] In step S1, the crushing and stirring process specifically involves sequentially subjecting the material to an ultrasonic crusher for 10-60 minutes and then to magnetic stirring for 0.5-3 hours.

[0017] In step S2, the reaction time is 2 to 48 hours.

[0018] Step S3 specifically involves placing the mixture obtained in step S2 into a centrifuge and centrifuging it at a speed of 5000~12000 r / min for 5~10 min, discarding the supernatant; washing the precipitate with water 3~8 times, centrifuging it at the same speed after each wash and discarding the supernatant; and finally drying the washed product in an oven.

[0019] In step S3, the drying conditions are: time 4~12h, temperature 50~100℃.

[0020] Another aspect of the present invention provides a bifunctional filler for improving the anti-corrosion and wear resistance properties of coatings, which is prepared by the above-described preparation method.

[0021] Another aspect of the present invention provides a bifunctional filler for improving the corrosion resistance and wear resistance of coatings, comprising a silicon carbide core and a zinc phosphate compound coated on the surface; wherein the silicon carbide core is encapsulated within the zinc phosphate compound to form a core-shell structure. This filler can simultaneously improve the corrosion resistance (cathodic protection of zinc phosphate) and wear resistance (high hardness of silicon carbide) of coatings, and is suitable for systems such as cathodic electrophoretic paints and industrial anti-corrosion paints.

[0022] The process of zinc phosphate coating silicon carbide to form a core-shell structure is essentially a heterogeneous nucleation-directional growth process driven by interfacial chemical bonding. The reaction involves the following steps: 1) Surface activation: Ultrasonic crushing causes hydrolysis of the silicon carbide surface, generating Si-OH groups; 2) Ion anchoring: Zn 2+ 3) Oriented coating: PO4 is added dropwise to the negatively charged SiC surface via electrostatic bonding (forming Si-O-Zn bonds); 3- Afterwards, adsorbed Zn 2+ The filler preferentially reacts with phosphate ions at the interface to form nuclei, and then grows epitaxially along the silicon carbide surface to form a continuous zinc phosphate shell, ultimately achieving molecular-level coating through chemical bonds (Si-O-Zn / Zn-OP). This process avoids homogeneous precipitation, forming a dense core-shell structure, allowing the filler to simultaneously function as a wear-resistant framework of silicon carbide and a passivating and corrosion-resistant layer of zinc phosphate.

[0023] Another aspect of the present invention provides a coating compounding system comprising the above-mentioned bifunctional filler, wherein the amount of bifunctional filler added is 1-10 wt% of the total weight of the coating.

[0024] The bifunctional filler prepared by this invention has a reasonable structure and can be stably dispersed in electrophoretic coatings, improving the density and overall performance of the coating film. It can be widely used in cathodic electrophoretic coatings and industrial anti-corrosion paints.

[0025] The bifunctional filler provided by this invention, which enhances the corrosion resistance and wear resistance of coatings, offers the following benefits: the silicon carbide particle core has extremely high hardness, effectively resisting wear caused by friction and impact; its surface, uniformly coated with zinc phosphate, ensures even distribution within the coating, reducing voids and defects and further improving coating density and wear resistance. Simultaneously, the zinc phosphate shell releases corrosion-inhibiting ions upon contact with water, forming a dense passivation film on the metal substrate surface to block corrosion. Therefore, this functional filler achieves a synergistic improvement in both corrosion resistance and wear resistance, meeting the comprehensive high-performance requirements of coatings in the automotive and construction machinery industries. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the preparation process of the bifunctional filler proposed in this invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0029] Unless otherwise specified, the test methods or experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are obtained from conventional commercial sources or prepared by conventional methods.

[0030] Example 1

[0031] 1.363 g of ZnCl2 was added to 100 mL of deionized water and stirred until completely dissolved. 10 g of silicon carbide particles (0.1 μm in diameter) were added, and the mixture was first ultrasonically destroyed for 30 min, then magnetically stirred for 2 h to ensure uniform particle dispersion. 100 mL of 0.1 mol / L Na3PO4 solution was added dropwise to the suspension, and the reaction was carried out for 4 h with stirring. After the reaction was complete, the product was centrifuged at 5000 r / min for 10 min, and the supernatant was discarded. The precipitate was washed five times with water, centrifuged at the same speed after each wash, and the supernatant was discarded. Finally, the washed product was dried in an oven at 80 °C for 12 h to obtain the bifunctional filler.

[0032] Example 2

[0033] 1.61 g ZnSO4 was added to 100 mL of deionized water and stirred until completely dissolved. 10 g of silicon carbide particles (0.1 μm in diameter) were added, and the mixture was first ultrasonically destroyed for 30 min, then magnetically stirred for 2 h to ensure uniform particle dispersion. 100 mL of 0.1 mol / L Na3PO4 solution was added dropwise to the suspension, and the reaction was carried out for 4 h with stirring. After the reaction, the product was centrifuged at 8000 r / min for 8 min, and the supernatant was discarded. The precipitate was washed five times with water, centrifuged at the same speed after each wash, and the supernatant was discarded. Finally, the washed product was dried in an oven at 80 °C for 12 h to obtain the bifunctional filler.

[0034] Example 3

[0035] 8.05 g ZnCl2 was added to 100 mL of deionized water and stirred until completely dissolved. 10 g of silicon carbide particles (0.1 μm in diameter) were added, and the mixture was first ultrasonically destroyed for 30 min, then magnetically stirred for 2 h to ensure uniform particle dispersion. 100 mL of 0.5 mol / L Na3PO4 solution was added dropwise to the suspension, and the reaction was carried out for 4 h with stirring. After the reaction was complete, the product was centrifuged at 12000 r / min for 5 min, and the supernatant was discarded. The precipitate was washed five times with water, centrifuged at the same speed after each wash, and the supernatant was discarded. Finally, the washed product was dried in an oven at 80 °C for 12 h to obtain the bifunctional filler.

[0036] Example 4

[0037] 1.61 g ZnSO4 was added to 100 mL of deionized water and stirred until completely dissolved. 10 g of silicon carbide particles (5 μm in diameter) were added, and the mixture was first ultrasonically destroyed for 30 min, then magnetically stirred for 2 h to ensure uniform particle dispersion. 100 mL of 0.1 mol / L Na3PO4 solution was added dropwise to the suspension, and the reaction was carried out for 4 h with stirring. After the reaction was complete, the product was centrifuged at 5000 r / min for 10 min, and the supernatant was discarded. The precipitate was washed five times with water, centrifuged at the same speed after each wash, and the supernatant was discarded. Finally, the washed product was dried in an oven at 80 °C for 12 h to obtain the bifunctional filler.

[0038] Example 5

[0039] 1.89 g of Zn(NO3)2 was added to 100 mL of deionized water and stirred until completely dissolved. 10 g of silicon carbide particles (0.1 μm in diameter) were added, and the mixture was first ultrasonically destroyed for 30 min, then magnetically stirred for 2 h to ensure uniform particle dispersion. 100 mL of 0.1 mol / L Na3PO4 solution was added dropwise to the suspension, and the reaction was carried out for 4 h with stirring. After the reaction, the product was centrifuged at 5000 r / min for 10 min, and the supernatant was discarded. The precipitate was washed five times with water, centrifuged at the same speed after each wash, and the supernatant was discarded. Finally, the washed product was dried in an oven at 80 °C for 12 h to obtain the bifunctional filler.

[0040] Example 6

[0041] 1.61 g ZnSO4 was added to 100 mL of deionized water and stirred until completely dissolved. 10 g of silicon carbide particles (0.1 μm in diameter) were added, and the mixture was first ultrasonically destroyed for 30 min, then magnetically stirred for 2 h to ensure uniform particle dispersion. 100 mL of 0.1 mol / L (NH4)3PO4 solution was added dropwise to the suspension, and the reaction was carried out for 4 h with stirring. After the reaction was complete, the product was centrifuged at 5000 r / min for 10 min, and the supernatant was discarded. The precipitate was washed five times with water, centrifuged at the same speed after each wash, and the supernatant was discarded. Finally, the washed product was dried in an oven at 80 °C for 12 h to obtain the bifunctional filler.

[0042] Example 7

[0043] 1.61 g ZnSO4 was added to 100 mL of deionized water and stirred until completely dissolved. 10 g of silicon carbide particles (0.1 μm in diameter) were added, and the mixture was first ultrasonically destroyed for 30 min, then magnetically stirred for 2 h to ensure uniform particle dispersion. 100 mL of 0.1 mol / L Na3PO4 solution was added dropwise to the suspension, and the reaction was carried out for 12 h with stirring. After the reaction, the product was centrifuged at 5000 r / min for 10 min, and the supernatant was discarded. The precipitate was washed five times with water, centrifuged at the same speed after each wash, and the supernatant was discarded. Finally, the washed product was dried in an oven at 80 °C for 12 h to obtain the bifunctional filler.

[0044] Example 8

[0045] 1.61 g ZnSO4 was added to 100 mL of deionized water and stirred until completely dissolved. 10 g of silicon carbide particles (5 μm in diameter) were added, and the mixture was first ultrasonically destroyed for 30 min, then magnetically stirred for 2 h to ensure uniform particle dispersion. 100 mL of 0.1 mol / L K3PO4 solution was added dropwise to the suspension, and the reaction was carried out for 4 h with stirring. After the reaction was complete, the product was centrifuged at 5000 r / min for 10 min, and the supernatant was discarded. The precipitate was washed five times with water, centrifuged at the same speed after each wash, and the supernatant was discarded. Finally, the washed product was dried in an oven at 80 °C for 12 h to obtain the bifunctional filler.

[0046] The effectiveness of the bifunctional fillers prepared in Examples 1-8 in improving the coating film performance was verified through experiments. The experimental procedures are as follows:

[0047] 1. Adding it to cathodic electrophoresis. 25g of bifunctional filler was added to 475g of cationic resin (epoxy acrylic type, produced by Swan Coatings Co., Ltd.), and ground in a ball mill for 5 hours to ensure uniform dispersion of the filler in the resin. 500g of deionized water was added dropwise at a rate of 85r / min under stirring to rapidly emulsify, obtaining a functional filler / cationic resin composite emulsion. The functional filler / cationic resin composite emulsion was diluted with deionized water at a 1:1 ratio, stirred evenly, and then, under the influence of an electric field using a DC power supply, a dense coating was formed on the steel plate surface. The surface paint was then rinsed with deionized water to remove any loose paint, and cured in an oven at 160℃ for 30 minutes to obtain the corresponding electrophoretic coating film. Its performance was then evaluated. For comparison, an electrophoretic coating film without the bifunctional filler was also prepared using the same cathodic electrophoresis process. Table 1 lists the performance of different samples, fully demonstrating that the bifunctional filler proposed in this invention can effectively improve the corrosion resistance and wear resistance of the coating film.

[0048] 2. Adding it to water-based axle paint slurry. Add 25g of bifunctional filler to 475g of TE240 water-based axle paint slurry, stir evenly, and then grind in a ball mill for 2 hours to achieve a fineness of less than 25μm. Mix the prepared slurry with water-based epoxy ester resin at a 1:1 ratio to prepare a water-based axle anti-corrosion paint. Spray the mixture onto a 75*150mm cold-rolled steel plate substrate, achieving a film thickness of 50-60μm. Curing is performed in an oven at 80℃ for 30 minutes to obtain the corresponding paint film. Performance is evaluated after 7 days of room temperature curing. For comparison, a water-based axle anti-corrosion paint film without the bifunctional filler was also prepared using the same process. Table 2 lists the performance of different samples, fully demonstrating that the bifunctional filler proposed in this invention can effectively improve the anti-corrosion and wear-resistant properties of the paint film.

[0049] Table 1. Comparison of technical specifications of cathodic electrophoretic coatings containing different bifunctional fillers

[0050]

[0051] Table 2 Comparison of technical specifications of water-based anti-corrosion paints for vehicle axles containing different dual-functional fillers

[0052]

[0053] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a bifunctional filler to improve the corrosion resistance and wear resistance of coatings, characterized in that: It includes the following steps: S1. Add soluble zinc salt to deionized water and stir until completely dissolved; then add silicon carbide particles, and after crushing and stirring, disperse the particles evenly. S2. Add a soluble phosphate aqueous solution to the suspension system obtained in step S1, and allow it to react completely under stirring. S3. After separating, washing and drying the mixture obtained in step S2, a bifunctional filler that improves the anti-corrosion and wear resistance of the coating is obtained.

2. The method for preparing the bifunctional filler for improving the corrosion resistance and wear resistance of coatings according to claim 1, characterized in that: The molar concentration of the soluble zinc salt is 0.1~1 mol / L; The mass ratio of the silicon carbide particles to the soluble zinc salt is 1~10:1; The molar ratio of the soluble phosphate to the soluble zinc salt is 0.5 to 2:

1.

3. The method for preparing the bifunctional filler for improving the corrosion resistance and wear resistance of coatings according to claim 1, characterized in that: The soluble zinc salt is one or more of ZnCl2, ZnSO4, or Zn(NO3)2; the soluble phosphate is one or more of Na3PO4, K3PO4, or (NH4)3PO4.

4. The method for preparing the bifunctional filler for improving the corrosion resistance and wear resistance of coatings according to claim 1, characterized in that: The silicon carbide particles have a particle size of 0.05~10μm.

5. The method for preparing the bifunctional filler for improving the corrosion resistance and wear resistance of coatings according to claim 1, characterized in that: In step S1, the crushing and stirring process specifically involves sequentially subjecting the material to an ultrasonic crusher for 10-60 minutes and then to magnetic stirring for 0.5-3 hours. In step S2, the reaction time is 2 to 48 hours.

6. The method for preparing the bifunctional filler for improving the corrosion resistance and wear resistance of coatings according to claim 1, characterized in that: Step S3 specifically involves placing the mixture obtained in step S2 into a centrifuge and centrifuging it at a speed of 5000~12000 r / min for 5~10 min, then discarding the supernatant. Wash the precipitate with water 3 to 8 times. After each wash, centrifuge at the same speed and discard the supernatant. Finally, the washed product is placed in an oven to dry.

7. The method for preparing the bifunctional filler for improving the corrosion resistance and wear resistance of coatings according to claim 6, characterized in that: In step S3, the drying conditions are: time 4~12h, temperature 50~100℃.

8. A bifunctional filler for improving the corrosion resistance and wear resistance of coatings, characterized in that: It is prepared by the preparation method according to any one of claims 1-7.

9. A bifunctional filler for improving the corrosion resistance and wear resistance of coatings, characterized in that: It consists of a silicon carbide core and a zinc phosphate compound coating on its surface; wherein the silicon carbide core is encapsulated within the zinc phosphate compound to form a core-shell structure.

10. A coating compounding system, characterized in that: It contains the bifunctional filler as described in claim 8 or 9, wherein the amount of bifunctional filler added is 1-10 wt% of the total weight of the coating.

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