TWI764677B - Lubricant additive for coating with oxidation resistance at high temperature and method of using same - Google Patents

Abstract

The present invention relates to a lubricant additive for a coating with oxidation resistance at a high temperature and a method of using same. The lubricant additive is at liquid state and a mass ratio with the lubricant additive to the coating with oxidation resistance at a high temperature is controlled, such that coating compositions with oxidation resistance at a high temperature containing the lubricant additive have a good stability. Further, a lubricant with a high-temperature resistance (A) in the lubricant additive contains a flake composition and/or a spherical composition, such that a coating film formed by the coating compositions has good adhesion and oxidation resistant at a high temperature, thereby enhancing a hot-stamping formability of a film-coated steel plate.

Description

Lubricating additive for high temperature oxidation resistant paint and method of using the same

The present invention relates to a lubricating additive for high temperature oxidation resistant coatings and a method of using the same, in particular to a lubricating additive for high temperature oxidation resistant coatings that can improve the hot stamping formability of steel sheets and a method of using the same.

Hot stamping is commonly used to make lightweight and high-strength automotive workpieces. In the hot stamping process of the hot stamping method, the boron steel is first heated to a temperature of not less than 900°C to carry out the ironization of the iron. Then quickly transfer the boron steel to the stamping die for high-speed stamping. Then, in the mold, pressure-hold quenching is performed on the boron steel at a cooling rate greater than 27° C./s to obtain an ultra-high-strength (for example, tensile strength greater than 1470MPa) steel workpiece with a uniform matian phase structure. Since the exposed surface of boron steel is easily oxidized to scale at high temperature, it must be heat treated in a protective gas environment.

However, in the process of transferring boron steel to the mold, oxidation and decarburization cannot be avoided, so it must be processed by Sand Blasting or Shot Peening (for example, using Shot Ball) to prevent Maintain the surface properties of the steel sheet (eg surface smoothness). The aforementioned decarburization will reduce the strength of the steel surface, while oxidation will produce scale (i.e. oxide scale), which will increase the friction coefficient between the steel plate and the mold, and reduce the life of the mold and the production efficiency of the workpiece.

A method to avoid oxidation is to form an aluminum-silicon coating and a high-temperature oxidation-resistant coating on the surface of the steel plate. Because of its high-temperature oxidation resistance, bead-strike processing is not required, and the process time is saved. In addition, the aluminum-silicon coating and the high-temperature oxidation resistant coating have good corrosion resistance, and are gradually widely used in the industry.

However, since both the aluminum-silicon coating and the high-temperature oxidation resistant coating have an aluminum-rich surface, the high temperature of hot stamping will reduce the adhesion of the two to the steel plate, causing them to fall off the surface of the steel plate and stick to the mold. Therefore, the friction coefficient of the interface between the steel plate and the mold is increased, thereby reducing the hot stamping formability of the steel plate. After continuous production, the increased friction coefficient will wear out the mold and scratch the formed workpiece. Therefore, additional production has to be stopped to clean the surface of the mold after sticking, thus reducing the production efficiency. In addition, the scratched parts of the workpiece are prone to oxidation and rust, which affects the uniformity of subsequent coating.

In other words, it is possible to apply a high temperature oxidation resistant coating on the surface of the steel sheet to form a high temperature oxidation resistant coating film and obtain a coated steel sheet (ie, a steel sheet with a coating film on the surface). However, when the high temperature oxidation resistant coating is prepared, the solid lubricating additive is directly added to the coating, which tends to thicken the coating and reduce its stability. Furthermore, if the lubricating additive is excessively added, the electrical conductivity of the steel sheet is lowered, and it becomes a defect in the welding of workpieces.

Another method to improve the stability of the coating is to coat the surface of the mold and spray it with lubricating coatings or lubricant additives during stamping to maintain the lubricity of the interface between the steel plate and the mold. However, in a high temperature environment, when continuous stamping is performed, the coated mold will still be gradually worn out with the increase of the number of uses, and it is difficult to re-coat the film. In addition, problems such as the amount of lubricating paint sprayed and its subsequent cleaning also reduce the production efficiency of hot stamping workpieces.

In view of this, there is an urgent need to develop a new lubricant additive for high temperature oxidation resistant coatings and a method of using the same, so as to improve the above-mentioned shortcomings of the conventional high temperature oxidation resistant coatings and coatings.

In view of the above problems, one aspect of the present invention is to provide a lubricant additive for high temperature oxidation resistant coatings. Since the lubricating additive is liquid and its mass ratio to the high temperature oxidation resistant coating is controlled, the high temperature oxidation resistant coating composition containing it has good stability. Further, the high temperature resistant lubricant (A) in the lubricating additive contains flake and/or spherical composition, so the coating film formed by the coating composition has good adhesion and high temperature oxidation resistance, thereby improving the coating film Hot stamping formability of steel sheets.

Another aspect of the present invention is to provide a method of using a lubricant additive for high temperature oxidation resistant coatings. This method of use uses the aforementioned lubricant additive in liquid state, and controls the mass ratio of the aforementioned lubricant additive to the anti-oxidative high temperature paint, thereby improving the hot stamping formability of the coated steel sheet.

According to an aspect of the present invention, a lubricating additive for high temperature oxidation resistant coatings is provided. The lubricating additive comprises a high temperature lubricant (A), a metal oxide (B), a self-lubricating compound (C), a dispersant (D) and a solvent (E). This lubricant additive is a liquid lubricant. Based on the weight of the lubricant additive being 100% by weight, the content of the high temperature resistant lubricant (A) is 10% to 35% by weight, the content of the metal oxide (B) is 10% to 25% by weight, the self-lubricating compound ( The content of C) is 5 to 20 wt%, the content of dispersant (D) is 0.5 to 10 wt%, and the content of solvent (E) is 20 to 40 wt%.

According to an embodiment of the present invention, the ratio of the thickness to the length of the sheet-like composition is 1:3 to 1:100.

According to another embodiment of the present invention, the particle size (D ₅₀ ) of the spherical composition is 0.5 μm to 20 μm.

According to another embodiment of the present invention, the particle size (D ₅₀ ) of the metal oxide (B) is 10 nm to 5 μm.

According to yet another embodiment of the present invention, the melting point of the self-lubricating compound (C) is 50°C to 400°C.

According to yet another embodiment of the present invention, the density of the self-lubricating compound (C) is 0.5 g/cm ³ to 3.0 g/cm ³ .

According to another embodiment of the present invention, the pyrolysis temperature of the self-lubricating compound (C) is not less than 300°C.

According to another embodiment of the present invention, the content ratio of the high temperature resistant lubricant (A), the metal oxide (B) and the self-lubricating compound (C) is 3:1:1 to 1:1:1.

According to another embodiment of the present invention, the boiling point of the solvent (E) is greater than 100°C.

Another aspect of the present invention provides a method of using a lubricant additive for high temperature oxidation resistant coatings. The using method includes adding the aforementioned lubricant additive for high temperature oxidation resistant coating to the high temperature oxidation resistant coating to obtain the high temperature oxidation resistant coating composition. The mass ratio of lubricating additive for high temperature oxidation resistant paint to high temperature oxidation resistant paint is 0.2 to 0.6.

Applying the lubricating additive for high temperature oxidation resistant paint and using method of the present invention, wherein the lubricating additive is liquid, and the mass ratio of the lubricating additive to the high temperature oxidation resistant paint is controlled, and the high temperature oxidation resistant paint composition containing it has good stability. Further, the high temperature resistant lubricant (A) in the lubricating additive contains a flake composition and/or a spherical composition, and the coating film formed by the coating composition has both good adhesion and high temperature oxidation resistance, thereby improving the coating film. Hot stamping formability of steel sheets.

The manufacture and use of embodiments of the present invention are discussed in detail below. It should be appreciated, however, that the embodiments provide many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are provided for illustration only, and are not intended to limit the scope of the invention.

The lubricating additive for high-temperature oxidation-resistant paint of the present invention is added to the high-temperature oxidation-resistant paint to obtain a high-temperature oxidation-resistant paint composition. In detail, the mass ratio of the lubricating additive to the high temperature oxidation resistant coating can be adjusted according to the needs of the appearance of the molded workpiece, and the lubricating additive can be added to the high temperature oxidation resistant coatings of different solution systems without reducing the stability of the coating composition. sex. Furthermore, the coating film formed by the coating composition has good adhesion and high temperature oxidation resistance, thereby improving the hot stamping formability of the coated steel sheet.

The aforementioned lubricating additives for high temperature oxidation resistant coatings include high temperature resistant lubricants (A), metal oxides (B), self-lubricating compounds (C), dispersants (D) and solvents (E). This lubricant additive is a liquid additive. When the lubricating additive is not in a liquid state, the lubricating additive added to the high temperature oxidation resistant coating tends to thicken the coating and reduce the stability of the coating composition.

The high temperature resistant lubricant (A) has high temperature resistant properties, which means that the high temperature resistant lubricant (A) will not melt at the highest temperature during hot stamping. In some embodiments, this maximum temperature may be no greater than 950°C. When the temperature is not higher than 950°C, the high temperature lubricant (A) will not melt, but can effectively prevent the coating film from adhering to the mold during hot stamping, and can reduce the friction between the steel and the mold, thereby improving the coating film. The adhesion and hot stamping formability of the coated steel sheet.

The high temperature resistant lubricant (A) includes a flake and/or spherical composition, wherein the flake and spherical refer to the shape of the high temperature lubricant (A). Preferably, the high temperature resistant lubricant (A) is a chemically inert solid material. When the high temperature resistant lubricant (A) does not contain a flake composition or a spherical composition, the high temperature resistant lubricant (A) cannot be arranged in an overlapping form with the metal filler in the high temperature oxidation resistant coating, which increases the penetration of oxygen to the The probability of steel plate, and then reduce the high temperature oxidation resistance of the coating. Preferably, the morphology of the high temperature resistant lubricant (A) can be powder or paste.

In some specific examples, the ratio of the thickness to the length of the sheet-like composition of the high temperature resistant lubricant (A) is 1:3 to 1:100, and preferably 1:3 to 1:50. When the ratio of the thickness to the length of the flake composition is 1:3 to 1:100, the flake composition helps the stacking of micron-sized metal flakes in the coating film and improves its high temperature oxidation resistance. In some embodiments, specific examples of the flake composition of the high temperature resistant lubricant (A) may include talc, mica, borax, graphite, graphite fluoride, titanium ionide, cerium fluoride, flake molybdenum compound and flake The tungsten compound is preferably titanium ionide.

In other specific examples, the particle size (D ₅₀ ) of the spherical composition of the high temperature resistant lubricant (A) may be 0.5 μm to 20 μm, and preferably 1 μm to 10 μm. When the particle size (D ₅₀ ) of the spherical composition is 0.5 μm to 20 μm, the coating film has good lubricity to improve its high temperature oxidation resistance, and the dispersion of the high temperature resistant lubricant (A) is good, so the lubricant additive Has a suitable viscosity and improves the stability of the coating. In some embodiments, specific examples of the spherical composition of the high temperature resistant lubricant (A) may include borax, carbon black, spherical molybdenum compound and spherical tungsten compound, and carbon black is preferred.

In some embodiments, the content of the high temperature resistant lubricant (A) is 10 to 35 wt %, preferably 20 wt %, based on 100 wt. Weight percent to 30 weight percent. When the content of the high temperature resistant lubricant (A) is less than 10 wt%, it is difficult for the coating film to provide sufficient buffering at the interface between the mold and the steel plate during hot stamping, thereby increasing the probability of scratching the mold. When the content of the high temperature resistant lubricant (A) is more than 35 weight percent, the stability of the lubricating additive is reduced.

The metal oxide (B) can react with the binder in the high temperature oxidation resistant coating to form a denser coating film and increase its hardness, thereby improving its wear resistance and hot stamping formability.

In some embodiments, the metal oxide (B) may be granular, and its particle size (D ₅₀ ) is 10 nm to 5 μm, and preferably 30 nm to 500 nm. When the particle size (D ₅₀ ) of the metal oxide (B) is 10 nm to 5 μm, the dispersibility of the metal oxide (B) is good, and the stacking of micron-sized metal flakes in the high-temperature oxidation coating is promoted, thus improving the coating film. Corrosion resistance. In some specific examples, the particle size (D ₉₀ ) of the metal oxide (B) may be less than 10 μm, preferably 500 nm to 5 μm. When the particle size (D ₉₀ ) of the metal oxide (B) is less than 10 μm, the metal oxide (B) is not easy to agglomerate, thus reducing the surface roughness of the coating film and improving its hot stamping formability. In some embodiments, the metal oxide (B) may comprise alumina, magnesia, calcia, zirconia, zinc oxide and titania, and preferably may be particles of alumina and titania.

In some embodiments, the content of the metal oxide (B) is 10 to 25% by weight, preferably 10 to 18% by weight, based on 100% by weight of the lubricating additive for high temperature oxidation resistant coatings . When the content of the metal oxide (B) is less than 10 wt%, the thickness of the coating film becomes thinner, and it is difficult to resist the shear force from the mold, which leads to the cracking of the coating film and reduces its lubricity and hot stamping formability. On the contrary, when the content of metal oxide (B) is more than 25% by weight, metal oxide (B) tends to aggregate into large particles, thus increasing the surface roughness of the coating film and reducing its lubricity and hot stamping of the coated steel sheet. Formability.

In some specific examples, the surface of the metal oxide (B) has reactive functional groups, and these reactive functional groups can make the structure of the coating film formed by the coating composition more compact and increase its hardness, thereby effectively reducing the workpiece during molding. The degree of scratching is improved, and the hot stamping formability of the coated steel sheet is improved. For example, reactive functional groups may include amine groups, carboxyl groups, cycloethoxy groups, alkenyl groups, and alcohol groups.

The self-lubricating compound (C) refers to an organic substance having lubricating properties, and this lubricating property can be determined by at least one of a specific melting point, density and cracking temperature. Due to the lubricating properties of the self-lubricating compound (C) itself, the lubricity of the coating film can be improved, thereby improving the hot stamping formability of the coated steel sheet.

In some embodiments, the self-lubricating compound (C) has a suitable melting point and low density, which may be 50°C to 400°C and 0.5 g/cm ³ to 3.0 g/cm ³ , respectively. Preferably, the melting point may be 125°C to 350°C, and the density may be 1.0 g/cm ³ to 2.5 g/cm ³ . When the melting point and density of the self-lubricating compound (C) are within the aforementioned ranges, during the heating process of hot stamping, the self-lubricating compound (C) gradually migrates to the surface of the coating film, thereby increasing the lubricity and wear resistance of the coated steel sheet , thereby improving its hot stamping formability.

In some embodiments, the pyrolysis temperature of the self-lubricating compound (C) is not less than 300°C, and preferably 300°C to 550°C. Although the self-lubricating compound (C) starts to crack at above 300°C, due to the short heat treatment time of the hot stamping process (for example: 5 minutes to 10 minutes), some self-lubricating compounds ( C), so the self-lubricating compound (C) can continue to exert its lubricating effect. In addition, during the heating process, the self-lubricating compound (C) reacts with oxygen and is burned off to protect the metal filler in the high temperature oxidation resistant coating and keep it from being oxidized, thereby ensuring that the coating composition remains stable after hot stamping. maintain sufficient conductivity.

In some embodiments, the self-lubricating compound (C) may comprise stearates, solid organic waxes, polymers, organic resins, and any mixtures thereof. In other words, specific examples of stearate can be, but not limited to, sodium stearate, barium stearate and zinc stearate. Furthermore, specific examples of the solid organic wax may be, but not limited to, paraffin wax and microcrystalline wax.

For example, but not limited thereto, specific examples of the polymer can be polyethylene, polypropylene, polyamide, polysiloxane and polytetrafluoroethylene, and polypropylene and polytetrafluoroethylene are preferred . In addition, specific examples of the organic resin may be, but not limited to, epoxy resin, phenolic resin and polyester resin. The aforementioned various self-lubricating compounds (C) may be used alone or in combination, and the mixing ratio is not limited.

In some embodiments, the content of the self-lubricating compound (C) is 5 to 20 wt %, preferably 5 to 15 wt %, based on 100 wt % of the lubricating additive for high temperature oxidation resistant coatings . When the content of the self-lubricating compound (C) is less than 5% by weight, the lubricity of the coating film decreases. On the contrary, when the content of the self-lubricating compound (C) is greater than 20 weight percent, the self-lubricating compound (C) will remain too much carbide after hot stamping, causing pollution.

In some embodiments, the high temperature resistant lubricant (A), the metal oxide (B) and the self-lubricating compound (C) may act synergistically to improve the lubricity of the coating film. In some specific examples, the content ratio of the high temperature resistant lubricant (A), the metal oxide (B) and the self-lubricating compound (C) is 3:1:1 to 1:1:1, and preferably 2:1: 0.5:1 to 2:1:1. When the content ratio of the three is within the aforementioned range, the lubricity of the coating film and the hot stamping formability of the coated steel sheet can be improved, thereby reducing the loss of the die.

The dispersant (D) can help disperse insoluble substances such as the high temperature resistant lubricant (A) and the metal oxide (B) in the solvent. In some embodiments, the dispersant (D) may comprise a polymeric, anionic, cationic or nonionic dispersant. In other embodiments, the anionic and cationic types are not present at the same time, and other dispersants may be used in combination.

For example, specific examples of the polymer-type dispersant (D) can include polyesters, polyurethanes, and polyacrylates. Specific examples of the anionic dispersant (D) may contain a sulfonate compound. Specific examples of the cationic dispersant (D) may contain amine salt compounds and quaternary ammonium salt compounds. Specific examples of the nonionic dispersant (D) may contain an oleic acid compound and a polycaprolactone polyol (Polycaprolactone Diol). The aforementioned oleic acid compound may include oleic acid, ricinoleic acid and butyl oleate. The dispersing agent (D) in this case is not limited to these dispersing agents, but is for the purpose of helping to disperse insoluble substances such as the high temperature lubricant (A) and the metal oxide (B) in the solvent.

In some embodiments, the content of the dispersant (D) is 0.5 to 10 wt %, preferably 0.5 to 5 wt %, based on 100 wt % of the lubricating additive for high temperature oxidation resistant coatings. When the content of the dispersant (D) is less than 0.5 weight percent, the dispersant (D) cannot help the insoluble substances such as the high temperature lubricant (A) and the metal oxide (B) to be dispersed in the solvent, thereby reducing the stability of the coating composition sex. When the content of dispersant (D) is more than 10 wt%, excessive amount of dispersant (D) is likely to leave too much carbide after hot stamping, which will cause pollution, thus reducing the hot stamping formability of the coated steel sheet.

In some embodiments, the solvent (E) may comprise water or an organic solvent, depending on the solution system of the high temperature oxidation resistant coating. For example, if the high temperature oxidation resistant coating is an aqueous system, the solvent (E) contains water. The aforementioned organic solvents may include, but are not limited to, esters, aromatics, alcohols, ketones, alcohol ethers and aliphatic solvents.

The aforementioned solvents can be used alone or in combination, and the mixing ratio is not particularly limited, except that they can be uniformly mixed with each other to form a homogeneous state and can dissolve or disperse the high temperature resistant lubricant (A), metal oxide (B) , self-lubricating compound (C) and dispersant (D) for the purpose of making the lubricating additive present in a homogeneous liquid state. For example, specific examples of the solvent (E) may include water, acetone, isopropanol, n-butanol, isobutanol, xylene, ethylene glycol monobutyl ether and diethylene glycol methyl ether, and preferably For ethylene glycol monobutyl ether.

In some embodiments, the boiling point of solvent (E) is greater than 100°C, and preferably may be 120°C to 200°C. After the coating composition is coated on the steel plate, a coating film is formed after baking. If the solvent (E) is slowly dried during the baking process, no holes and/or air bubbles will be generated in the coating film, and It can improve the film-forming property of the coating film, thereby improving its lubricity and the hot stamping formability of the coated steel sheet.

In some embodiments, the content of the solvent (E) is 20 to 40 wt %, preferably 25 to 35 wt %, based on 100 wt % of the lubricating additive for high temperature oxidation resistant coatings. When the content of the solvent (E) is less than 20 weight percent, it is difficult for the solvent (E) to completely disperse all the components in the lubricating additive for high temperature oxidation resistant coatings, thereby reducing the stability of the coating composition. When the content of the solvent (E) is more than 40 wt%, the solvent (E) tends to generate bubbles and/or holes when the coating film is dried, thereby reducing its formability and lubricity, thus reducing the hot stamping formability of the coated steel sheet.

Another object of the present invention is to provide a method of using a lubricant additive for high temperature oxidation resistant coatings. The using method includes an adding step for adding the aforementioned lubricating additive for high temperature oxidation resistant paint into the high temperature oxidation resistant paint, so as to obtain the high temperature oxidation resistant paint composition.

In some embodiments, the high temperature oxidation resistant coating includes a binder and a plurality of micron-sized metal flakes. In some embodiments, the material of the micron-sized metal sheet may include, but not limited to, zinc, bismuth, or aluminum. Preferably, the high temperature oxidation resistant coating can be a high temperature oxidation resistant coating formulated according to the high temperature oxidation resistant coating formulations set forth in Patent Publication No. I488925 of the Republic of China and Patent Application No. 202043380 of the Republic of China.

The mass ratio of the added amount of the lubricating additive to the high temperature oxidation resistant coating is 0.2 to 0.6, and preferably 0.2 to 0.3. When the mass ratio of the two is less than 0.2, the scratch degree of the hot stamping workpiece cannot be significantly improved, and the hot stamping formability of the coated steel sheet is reduced. When the mass ratio of the two is greater than 0.6, although the degree of scratching of the hot stamping workpiece can be improved, the stability of the coating composition is reduced, and the formability and adhesion of the formed coating film are reduced, so the coated steel sheet is reduced. The hot stamping formability.

In some embodiments, this method of use may eliminate the step of spraying the high temperature oxidation resistant coating composition onto the mold surface prior to stamping the workpiece. In other words, compared with the traditional lubricant additives, this lubricant additive can be directly added to the high temperature oxidation resistant coating without spraying on the surface of the mold before the workpiece is stamped, so it will not cause additional pollution during stamping.

Accordingly, the method of using the lubricating additive for high temperature oxidation resistant paint of the present invention can reduce the friction coefficient of the interface between the steel sheet and the film, and improve the hot stamping formability of the coated steel sheet. In addition, since the procedure of cleaning the mold and the installation time and cost of the lubricating additive spraying equipment are reduced, the use method can greatly improve the production efficiency of the hot stamping workpiece.

In some embodiments, before adding the lubricating additive to the coating, the method of use may optionally include a pre-stirring step to uniformly mix the lubricating additive with the coating. The pre-stirring step can be performed by means of equipment and methods commonly used by those skilled in the art to which the present invention pertains. For example, a mechanical stirrer can be used and the stirring time can be about 30 minutes.

In some embodiments, before adding the lubricating additive to the coating, the method of use can selectively perform a viscosity measurement step on the coating composition to ensure that the viscosity of the coating composition is within a predetermined range, so as to ensure the viscosity of the coating composition. formability. In some embodiments, the step of measuring the viscosity of the coating composition is performed between the pre-stirring step and the adding step.

There are no specific limitations on the way in which the viscosity of the coating composition can be measured. In some specific examples, the viscosity of the coating composition can be measured using a No. 4 Ford cup, and the measured value is 10 seconds to 50 seconds, and preferably 10 seconds to 40 seconds. When the measured value of the viscosity of the coating composition is within the aforementioned range, it is favorable for the coating to be coated on the steel sheet, thereby improving the formability of the coating film, thereby improving the hot stamping formability of the coated steel sheet.

In some specific examples, the thickness of the coating film formed by the high temperature oxidation resistant coating composition is not more than 10 μm, and preferably can be 0.5 μm to 5 μm. When the thickness of the coating film is not more than 10 μm, the coating film has an appropriate thickness and can resist the shear force generated by the mold, so the lubricity of the coating film is improved.

The following examples are used to illustrate the application of the present invention, but it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention.

Preparation of Lubricant Additives (F)

Example 1

The lubricant additive (F) of Example 1 is in accordance with the composition formula shown in Table 1, and the high temperature resistant lubricant (A) and the solvent (E) are added into a flask equipped with a stirrer and a thermometer. At room temperature, stir for 30 minutes to uniformly mix, and then gradually add metal oxide (B), self-lubricating compound (C) and dispersant (D) to the aforementioned mixture, and continue at a temperature of less than 40 ° C. After stirring for 1 hour, the lubricant additive (F) of Example 1 was obtained, and the viscosity was measured according to the evaluation method described later. The evaluation results are shown in Table 1.

Examples 2 to 8

Examples 2 to 8 were all prepared in the same manner as in Example 1 to prepare lubricant additives. The difference is that Examples 2 to 8 change the types and contents of the compositions, and the specific conditions and evaluation results are shown in Table 1.

Application of Lubricant Additives

Application example 1

In Application Example 1, the lubricant additive (F) of Example 1 was stirred at room temperature for 30 minutes, and then mixed according to the mass ratio of the lubricant additive (F) and the high temperature oxidation resistant coating shown in Table 2. The mixture was stirred at room temperature for 1 hour, and then the mixture was filtered through a 300-mesh screen to obtain the coating composition of Application Example 1. Coat the coating composition on the steel plate, and dry it at 300°C to obtain the coating film of Application Example 1 with a thickness of 3 μm, and obtain the coated steel plate of Application Example 1 containing this coating film, and then use the following Evaluation method The coating composition, coating film and coated steel sheet of Application Example 1 were tested, and the results are listed in Table 2 in detail.

Application Examples 2 to 12 and Comparative Application Examples 1 to 2

Application Examples 2 to 12 were all produced in the same manner as Application Example 1 to manufacture coating compositions. The difference is that Application Examples 2 to 12 change the lubricating additives and high temperature oxidation resistant coatings, and the specific conditions and evaluation results are shown in Table 2.

Evaluation method

1. Viscosity test of coating composition

The viscosity test of the coating composition is to measure the viscosity of the lubricating additives in each example with a No. 4 Ford cup, and the unit of the measured value is seconds.

2. Coating composition and coating stability test

The coating composition and the stability test of the coating were used to measure the viscosity of the coating composition of each application example and the coating of each comparative application example with a No. 4 Ford cup, and stirred (rotation speed: 300 rpm) for 24 hours in the open cup state. Store these paint compositions and paints in a cool place for one month. After stirring for 2 hours, measure the viscosity of these coating compositions and coatings, and evaluate the stability based on the difference in viscosity before and after storage. The specific evaluation criteria are as follows: ◎: The difference in viscosity is less than 5 seconds. ○: The viscosity difference is 5 seconds to 10 seconds. ╳: The viscosity difference is greater than 10 seconds.

3. Coating adhesion test

The adhesion test of the coating film was carried out by a 100-grid test, in which a 100-grid knife was used to draw lines on the coating films of each application example and each comparative application example, and the cut coating films were pasted with tape, and then the tape was removed. Based on the original complete area of the coating film being 100%, calculate the percentage of the area of the coating film that has been peeled off by the tape, and use this percentage to indicate the degree of peeling of the coating film and evaluate its adhesion. The specific evaluation criteria are as follows: ⊚: The coating film was intact and did not fall off, and the peeling area was 0%. ○: The coating film is slightly peeled off, and the peeling area is less than 5%. Δ: The coating film is moderately peeled off, and its peeling area is 5% to 10%. ╳: The coating film is seriously peeled off, and the peeling area is more than 10%.

4. High temperature oxidation resistance test of coating film

In the high temperature oxidation resistance test, the coated steel sheets of each application example and each comparative application example were heated at 930°C for 5 minutes, and then subjected to hot stamping. After the tape was attached to the surface of the formed workpiece, the tape was removed. The high temperature oxidation resistance is evaluated by the degree of coating film peeling off, and the specific evaluation criteria are as follows: ⊚: The coating film was intact, and there was no peeling of the coating film remaining on the tape. ○: The coating film is slightly peeled off, and the tape has a small amount of peeling of the coating film. Δ: The coating film is moderately peeled off, and the tape has a small amount of peeling of the coating film. ╳: The coating film is seriously peeled off, the tape has a lot of peeling off of the coating film, and the coated steel plate produces oxide scale visible to the naked eye.

5. Hot stamping formability test of coated steel sheet

The hot stamping formability test of the coated steel sheet is to heat the coated steel sheet of each application example and each comparative application example at 930 ° C for 5 minutes, then quickly transfer it to the mold, and perform high-speed hot stamping on it. The appearance of the workpiece and the coating film after forming, and the hot stamping formability of the coated steel sheet is evaluated by the number of scratches. The specific evaluation criteria are as follows: ⊚: The coating film is complete, and the number of scratches is less than 2. ○: The coating film is slightly peeled off, and 2≦the number of scratches<5. Δ: The coating film is moderately peeled off, and 5≦the number of scratches<10. ╳: The coating film is seriously peeled off, and 10≦the number of scratches.

6. Corrosion resistance test of coated steel sheet

The corrosion resistance test of the coated steel sheet is in accordance with the Japanese industrial standards (JIS) No. Z-2371 standard method, and the coated steel sheet of each application example and each comparative application example is subjected to a salt spray test, and is observed with the naked eye. 5 The surface rusted area of these coated steel sheets after hours. Based on the complete surface area of the coated steel sheet being 100%, calculate the percentage of the rusted area, and use this percentage to evaluate the corrosion resistance of the coated steel sheet. The specific evaluation criteria are as follows: ◎: Corrosion area <10%. ○: 10%≦corrosion area＜30%. Δ: 30%≦corrosion area<50%. ╳: 50%≦corrosion area.

Table 1 Lubricant Additives (F) Composition (wt.%) (A), (B) and (C) ratio nature High temperature lubricant (A) Metal oxide (B) Self-lubricating compound (C) Dispersant (D) Solvent (E) Viscosity (sec) A1 A2 B1 B2 C1 C2 D1 E1 Example 1 30 0 10 0 15 0 3 40 2:0.7:1 30 2 30 0 0 10 0 15 3 40 2:0.7:1 30 3 0 30 10 0 15 0 3 40 2:0.7:1 40 4 0 30 10 0 0 15 3 40 2:0.7:1 40 5 30 0 10 2.5 15 0 4 40 2:0.8:1 33 6 10 10 5 13 15 0 5 40 2:1.2:1 18 7 0 10 0 10 0 5 0.5 20 2:2:1 10 8 15 10 10 0 15 0 4 30 1.7:0.7:1 25 A1 is (flaky) titanium ionide, and the ratio of its thickness to its length is 1:20. A2 is carbon black, and the particle size (D ₅₀ ) is 1 μm. B1 is a titanium dioxide particle, the particle size (D ₅₀ ) is 200 nm, the particle size (D ₉₀ ) is 700 nm, and the surface has an amine functional group. B2 is alumina particles, the particle size (D ₅₀ ) is 100 nm, the particle size (D ₉₀ ) is 500 nm, and the surface has an alcohol group functional group. C1 is polypropylene with a melting point of 150°C, a density of 0.9 g/cm ³ , and a cracking temperature of 410°C. C2 is polytetrafluoroethylene with a melting point of 327°C, a density of 2.2 g/cm ³ , and a cracking temperature of 350°C. D1 is an acid group-containing copolymer solution manufactured by BYK, and its product code is BYK-110. E1 is ethylene glycol monobutyl ether with a boiling point of 171°C.

Table 2 paint composition or coating coating film Coated steel plate composition nature adhesion High temperature oxidation resistance Hot stamping formability Corrosion resistance Lubricant Additives (F) High temperature oxidation resistant coating mass ratio stability Application example 1 Example 1 G1 0.3 ◎ ◎ ◎ ○ ○ 2 Example 2 G1 0.3 ○ ○ ◎ ○ ○ 3 Example 3 G1 0.2 ◎ ◎ ◎ ◎ ○ 4 Example 4 G1 0.2 ◎ ◎ ◎ ◎ ○ 5 Example 1 G2 0.3 ◎ ◎ ◎ ○ ○ 6 Example 2 G2 0.2 ○ ○ ◎ ○ ○ 7 Example 3 G2 0.2 ◎ ◎ ◎ ◎ ○ 8 Example 4 G2 0.3 ◎ ◎ ◎ ◎ ○ 9 Example 5 G1 0.4 ◎ ◎ ◎ ◎ ○ 10 Example 6 G1 0.5 ◎ ◎ ◎ ○ ○ 11 Example 7 G1 0.6 ○ ◎ ◎ ○ ○ 12 Example 8 G2 0.5 ◎ ○ ○ ○ ○ Comparative application example 1 none G1 N/A ◎ Δ ◎ Δ ○ 2 none G2 N/A ◎ ○ Δ ╳ ○ The mass ratio is the mass ratio of the lubricating additive to the high temperature oxidation resistant coating. N/A means no lubricating additive is used, and the mass ratio cannot be calculated. G1 is a high temperature oxidation resistant coating formulated in accordance with the high temperature oxidation resistant coating formulation contained in Patent Publication No. I488925 of the Republic of China. G2 is a high temperature oxidation resistant coating formulated in accordance with the high temperature oxidation resistant coating formulation contained in Patent Application No. 202043380 of the Republic of China.

Please refer to Tables 1 and 2. According to the results of viscosity and stability, the measured viscosity of the lubricating additives of each embodiment is 10 seconds to 40 seconds. The coating composition of each application example is prepared by mixing the lubricating additive of the previous embodiment and the high temperature oxidation resistant coating, and the mass ratio of the two is 0.2 to 0.6. The addition of additives will not reduce the stability of high temperature oxidation resistant coatings, but can still maintain good stability.

Secondly, according to the results of adhesion and high temperature oxidation resistance, the coating films of each application example can have good or better adhesion and high temperature oxidation resistance at the same time compared to the coating films of each comparative application example without adding lubricating additives Therefore, the coated steel sheet of each application example has better hot stamping formability. In other words, adding lubricating additives to the high-temperature oxidation resistant coating according to the aforementioned mass ratio will improve the hot stamping formability of the coated steel sheet.

On the contrary, compared with the coating films of each application example, the coating film of Comparative Application Example 1 had poor adhesion, and lowered its high temperature oxidation resistance and hot stamping formability. In addition, compared with the coating films of each application example, the coating film of Comparative Application Example 2 has poorer high temperature oxidation resistance, which reduces its hot stamping formability. It can be seen that the lubricating additive can make the coating film have both good or better adhesion and high temperature oxidation resistance, thereby improving the hot stamping formability of the coated steel sheet.

To sum up, the lubricating additive for high temperature oxidation resistant paint of the present invention is a liquid additive, and the mass ratio of it to the high temperature oxidation resistant paint is controlled, so the high temperature oxidation resistant paint composition containing it has good stability. Further, the high temperature resistant lubricant (A) containing the flake composition and/or the spherical composition can be arranged in an overlapping form with the metal filler in the high temperature oxidation resistant coating to improve the high temperature oxidation resistance of the coating film. In addition, the high temperature resistant lubricant (A) will not melt during hot stamping to prevent the coating film from adhering to the mold, thereby improving the adhesion and high temperature oxidation resistance of the coating film, as well as the hot stamping formability of the coated steel sheet.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the appended patent application.

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Claims (10)

A lubricating additive for high temperature oxidation resistant coatings, comprising: A high temperature resistant lubricant (A), comprising a sheet-like composition and/or a spherical composition; a metal oxide (B); a self-lubricating compound (C); a dispersant (D); and a solvent (E); Wherein the lubricating additive for high temperature oxidation resistant paint is a liquid lubricant, and based on a weight of the lubricating additive for high temperature oxidation resistant paint is 100 weight percent, a content of the high temperature resistant lubricant (A) is 10 weight percent to 35 weight percent Weight percent, a content of the metal oxide (B) is 10 weight percent to 25 weight percent, a content of the self-lubricating compound (C) is 5 weight percent to 20 weight percent, a content of the dispersant (D) The content of one of the solvents (E) is 20 to 40 percent by weight. The lubricating additive for high temperature oxidation resistant coatings as claimed in claim 1, wherein a ratio of a thickness to a length of the sheet-like composition is 1:3 to 1:100. The lubricating additive for high temperature oxidation resistant coatings according to claim 1, wherein one particle size (D ₅₀ ) of the spherical composition is 0.5 μm to 20 μm. The lubricating additive for high temperature oxidation resistant coatings according to claim 1, wherein a particle size (D ₅₀ ) of the metal oxide (B) is 10 nm to 5 μm. The lubricating additive for high temperature oxidation resistant coatings according to claim 1, wherein one of the melting points of the self-lubricating compound (C) is 50°C to 400°C. The lubricating additive for high temperature oxidation resistant coatings according to claim 1, wherein a density of the self-lubricating compound (C) is 0.5 g/cm ³ to 3.0 g/cm ³ . The lubricating additive for high temperature oxidation resistant coatings according to claim 1, wherein one of the cracking temperatures of the self-lubricating compound (C) is not less than 300°C. The lubricating additive for high temperature oxidation resistant coatings as claimed in claim 1, wherein a content ratio of the high temperature resistant lubricant (A), the metal oxide (B) and the self-lubricating compound (C) is 3:1:1 to 1:1:1. The lubricating additive for high temperature oxidation resistant coatings according to claim 1, wherein one of the boiling points of the solvent (E) is greater than 100°C. A method for using a lubricating additive for high temperature oxidation resistant coatings, comprising: Add the lubricating additive for the high temperature oxidation resistant coating as described in any one of claims 1 to 9 to the high temperature oxidation resistant coating to obtain a high temperature oxidation resistant coating composition, Wherein a mass ratio of the lubricating additive for high temperature oxidation resistant paint to the high temperature oxidation resistant paint is 0.2 to 0.6.