A production process for low-temperature baking color plates

Abstract

The present application discloses a production process for low-temperature baked color plates, comprising the following steps: (1) spraying and cleaning a metal plate with a degreasing solution, coating the surface of the metal plate with a passivating agent, and baking to obtain a treated metal plate; (2) coating the treated metal plate with a primer, drying and curing the metal plate to obtain a metal plate with a surface cured primer layer, wherein the primer components include epoxy resin, rutile titanium dioxide, modified talc, leveling agent, silicone oil defoaming agent, n-butanol, and butylated melamine resin; (3) spraying the treated metal plate with color paint, and then drying and curing the metal plate at a temperature of 110-115°C to obtain a low-temperature baked color plate; wherein the color paint components include polyester resin, propylene glycol methyl ether acetate, unsaturated polyvalent fatty amine dispersant, pigment, ceramic powder, leveling agent, and antibacterial composition. The color plates prepared in the present application have excellent antibacterial properties, mechanical properties, and adhesion.

Description

Technical Field

[0001] The present application relates to the technical field of boards, and in particular to a production process for low-temperature baking color boards. Background Art

[0002] Color plate refers to color-coated steel plate, which is a product made by continuous roller coating, baking and cooling after a series of surface treatment processes such as degreasing, cleaning, chemical conversion, etc. It is widely used in the walls and roofs of large public buildings, mobile houses, public factories and integrated houses, and is also used in the shells of home appliances such as refrigerators, washing machines, and air conditioners.

[0003] As people's living standards improve, their requirements for color plates are getting higher and higher. Color plates are decorated on the outside of buildings or home appliances and are often touched, which easily leads to the residue of bacteria. In the existing technology, an antibacterial layer, a primer layer, an antibacterial layer and a topcoat layer are sequentially coated on the surface of the steel plate. Since the antibacterial layer is located below the topcoat layer, when the surface of the steel plate is touched, bacteria will still remain on the topcoat layer, resulting in poor antibacterial effect. Summary of the Invention

[0004] In order to improve the problem that the antibacterial layer of the steel plate is located below the topcoat layer, resulting in poor antibacterial effect of the steel plate, the present application provides a production process for low-temperature baking color plates.

[0005] This application provides a production process for low-temperature baking color plates, which adopts the following technical solutions:

[0006] A production process for low-temperature baking color plates, comprising the following steps:

[0007] (1) using a degreasing solution to spray clean the metal plate at a temperature of 60-65°C for 1-2 minutes, then coating the surface of the metal plate with a passivating agent, and baking at a temperature of 140-145°C for 20-25 seconds to obtain a treated metal plate;

[0008] (2) coating the metal plate treated in step (1) with a primer, and then drying and curing the metal plate at a temperature of 120-125° C. to obtain a metal plate with a surface-cured primer layer, wherein the primer components include epoxy resin, rutile titanium dioxide, modified talc, leveling agent, silicone oil defoamer, n-butanol, and butylated melamine resin;

[0009] (3) spraying the metal plate treated in step (2) with colored paint, and then drying and curing it at a temperature of 110-115° C. to obtain a low-temperature baked colored plate;

[0010] The color paint components include polyester resin, propylene glycol methyl ether acetate, unsaturated polyvalent fatty amine dispersant, pigment, ceramic powder, leveling agent and antibacterial composition.

[0011] By adopting the above technical solution, the degreasing solution is used to clean the grease and dirt on the surface of the metal plate, and the passivation agent can form a stable chemical film on the surface of the metal plate to protect the surface of the metal plate from environmental corrosion, and then the primer and topcoat are applied in sequence.

[0012] In the primer, epoxy resin provides good adhesion, forming a strong bond with the surface of the metal plate, so that the subsequent colored paint can be firmly attached to the metal plate; rutile titanium dioxide has good hiding power, which can improve the chemical stability of the primer system, thereby enhancing the mechanical strength, corrosion resistance, adhesion, light resistance and weather resistance of the primer system; modified talc has good dispersibility and can act as a skeleton to improve the whiteness, water resistance and impermeability of the primer system; leveling agent can significantly reduce surface tension and eliminate the surface tension gradient of the wet film; n-butanol acts as a solvent to disperse the resin in the primer and adjust the viscosity and rheology of the system; butylated melamine resin has low viscosity and high cross-linking activity, and is used as a cross-linking agent to improve the mechanical properties, chemical stability and service life of the primer.

[0013] In the paint, polyester resin has good film-forming properties, chemical corrosion resistance, plump paint film, thick layer and hard surface; propylene glycol methyl ether acetate is used as a diluent to help improve the transparency, flexibility and durability of the paint; unsaturated polyvalent fatty amine dispersants reduce the interfacial tension between solid-liquid and liquid-liquid, increase the dispersion of each component in the paint, and improve the stability and rheological properties of the paint layer; pigments give the paint color and decorative properties; ceramic powder increases the adsorption, weather resistance, durability, and corrosion resistance of the paint, and changes the mechanical properties, transparency and wear resistance of the paint; the antibacterial composition can inhibit bacterial growth, prevent fungal growth, and provide a long-lasting antibacterial effect, so that the paint has good antibacterial properties, thereby improving the antibacterial properties of the metal plate.

[0014] Preferably, the primer components include, by weight, 30-50 parts of epoxy resin, 15-25 parts of rutile titanium dioxide, 5-12 parts of modified talc, 2-5 parts of leveling agent, 1-3 parts of silicone oil defoamer, 18-25 parts of n-butanol, and 6-9 parts of butylated melamine resin.

[0015] By adopting the above technical solution, the content of each component in the primer is further limited, and a primer composition with good mechanical properties, good water resistance and long service life is obtained. The various components cooperate with each other to jointly improve the comprehensive performance of the primer. The epoxy resin enhances the adhesion of the primer, making the primer bonded more tightly to the metal plate, and at the same time making the primer bonded more firmly to the color paint. The titanium dioxide and talcum powder are combined to improve the hiding power of the primer, and at the same time improve other properties of the primer such as the mechanical strength.

[0016] Preferably, the paint components include, by weight, 40-50 parts of polyester resin, 10-20 parts of propylene glycol methyl ether acetate, 5-10 parts of unsaturated polyvalent fatty amine dispersant, 10-15 parts of pigment, 9-13 parts of ceramic powder, 1-2 parts of leveling agent, and 12-18 parts of antibacterial composition.

[0017] By adopting the above technical solution, the content of each component in the colored paint is further limited, and a colored paint composition with good film-forming properties, chemical corrosion resistance and durability is obtained. The various components cooperate with each other to jointly improve the comprehensive performance of the colored paint. The polyester resin has good film-forming properties, and the ceramic powder improves the mechanical properties, durability and corrosion resistance of the colored paint. The antibacterial composition in the colored paint can inhibit bacterial growth, prevent fungal growth, and provide a long-lasting antibacterial effect, so that the colored paint has good antibacterial properties, thereby improving the antibacterial properties of the metal plate.

[0018] Preferably, the method for preparing the antibacterial composition comprises the following steps:

[0019] (1) The bamboo fibers were dispersed in citric acid and soaked for 20-30 min, washed with water, and then dispersed in anhydrous ethanol and ultrasonicated for 1-2 h to obtain a mixture 1;

[0020] (2) dispersing nanosilver in the extract of Camphor Tree Vine, stirring at a temperature of 60-70° C. for 1-2 h, and then adding it to the mixture 1 obtained in step (1), and continuing to stir for 2-4 h to obtain a mixture 2;

[0021] (3) Dispersing chitosan in acetic acid solution, then adding it to the mixture obtained in step (2), stirring at a temperature of 80-85° C. for 1-2 hours, filtering, and drying to obtain an antibacterial composition.

[0022] By adopting the above technical solution, the bamboo fiber is highly hollow, has a strong capillary effect, can absorb and evaporate moisture extremely quickly, can regulate the humidity of the subsequent metal plate, and also has the effects of thermal insulation, sound absorption, and reduction of indoor noise; citric acid erodes the surface of the bamboo fiber to a certain extent, making the surface of the bamboo fiber rough, increasing the specific surface area of the bamboo fiber, and further improving the adsorption performance of the bamboo fiber, which is conducive to subsequent mixing with other components.

[0023] Nanosilver has excellent antibacterial properties, a large specific surface area and high activity. It can react with bacteria, viruses and other microorganisms, destroy their cell membrane structure, inhibit their growth and reproduction, and thus achieve an antibacterial effect; the extract of Camphor Tree Vine has broad-spectrum and high-efficiency antibacterial activity, and also has good dispersion properties. Nanosilver is dispersed in the extract of Camphor Tree Vine, further improving the overall antibacterial properties; bamboo fiber is dispersed in mixture two, and nanosilver is loaded on the surface of the bamboo fiber, increasing the specific surface area and mechanical properties of the bamboo fiber. Chitosan has good film-forming properties. Chitosan and Camphor Tree Vine extract can be coated on the surface of the bamboo fiber, increasing the adhesion between the bamboo fiber and nanosilver, thereby improving the mechanical properties, antibacterial and chemical stability of the bamboo fiber. In the subsequent application in colored paint, it not only increases the mechanical properties, adhesion and antibacterial properties of the colored paint, but also increases the antibacterial durability of the colored paint.

[0024] Preferably, the mass ratio of the bamboo fiber, nanosilver and chitosan is 0.3-0.6:1:0.07-0.09.

[0025] By adopting the above technical solution, the mass ratio of bamboo fiber, nanosilver and chitosan is further limited within a certain range, and modified bamboo fiber with good antibacterial properties, excellent mechanical properties and good adhesion is obtained. There is a synergistic effect between bamboo fiber, nanosilver and chitosan. Nanosilver is loaded on the surface of bamboo fiber, and chitosan can increase the adhesion between nanosilver and bamboo fiber, thereby improving the comprehensive properties of bamboo fiber such as mechanical properties, adhesion and antibacterial properties.

[0026] Preferably, the preparation method of the modified talc powder comprises the following steps:

[0027] (1) Grinding talc to obtain a powder with a particle size of 20-30 nm, dispersing the powder in anhydrous ethanol, and stirring for 1-2 h to obtain a mixture 1;

[0028] (2) adding γ-cyclodextrin to the mixture 1 obtained in step (1), and ultrasonicating at a temperature of 60-65° C. for 30-45 minutes to obtain a mixture 2;

[0029] (3) Adding hydroxypropyl methylcellulose to the mixture obtained in step (2), ultrasonically treating the mixture at a temperature of 80-85° C. for 20-25 minutes to obtain modified talc.

[0030] By adopting the above technical solution, talcum powder is ground to obtain a powder with uniform particle size, which is conducive to subsequent dispersion. γ-cyclodextrin has good chemical stability, antioxidant effect and bactericidal properties. When mixed with talcum powder, it can improve the solubility and stability of talcum powder and help to evenly disperse the powder. Hydroxypropyl methylcellulose has thickening, bonding, dispersing, emulsifying and film-forming properties, so that talcum powder and γ-cyclodextrin are not only evenly mixed, but also can coat the talcum powder. When the talcum powder is subsequently used in the primer, it can increase the film-forming property of the primer components and make the components evenly mixed.

[0031] Preferably, the mass ratio of talc, γ-cyclodextrin and hydroxypropyl methylcellulose is 1:0.1-0.3:0.02-0.04.

[0032] By adopting the above technical solution, the mass ratio of talc, γ-cyclodextrin and hydroxypropyl methylcellulose is further limited within a certain range, and modified talc with excellent mechanical properties and good viscosity is obtained. γ-cyclodextrin not only increases the mechanical properties and adhesion of talc, but also increases the antibacterial properties of talc. Hydroxypropyl methylcellulose further makes the talc and γ-cyclodextrin mixed evenly, and increases the adhesion between talc and γ-cyclodextrin, which helps to change the antibacterial properties, mechanical properties and adhesion of talc. In the subsequent application in primer, it improves the adhesion between the primer and the metal plate, and between the primer and the color paint, and also helps to improve the comprehensive properties of the primer, such as the antibacterial properties.

[0033] Preferably, the pigment is one or more of an organic pigment, a transparent pigment, a pearlescent pigment, a multi-angle effect pigment and a metallic pigment.

[0034] By adopting the above technical solution, the pigment can give the paint color and decorativeness, increase the strength and adhesion of the paint film, reduce the shrinkage of the paint, enhance the adhesion, corrosion resistance, light resistance and weather resistance of the paint, and help to make the paint and primer bond tightly.

[0035] Preferably, the leveling agent is one or a combination of silicone leveling agent, polyacrylate leveling agent, and fluorosurfactant.

[0036] By adopting the above technical solution, the leveling agent can promote the primer and topcoat to form a flat, smooth and uniform coating film during the drying and film-forming process, effectively reduce the surface tension of the coating liquid, improve its leveling and uniformity, improve the permeability of the coating liquid, reduce the possibility of spots and marks during use, increase coverage, and make the film formation uniform and natural.

[0037] Preferably, the metal plate is selected from one of an aluminum plate, an aluminum alloy plate, a tinplate plate, a hot-dip galvanized plate, an electro-galvanized plate, a stainless steel plate and a cold-rolled steel plate.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. In this application, a degreasing solution is used to clean the grease and dirt on the surface of the metal plate. The passivating agent can form a stable chemical film on the surface of the metal plate to protect the surface of the metal plate from environmental corrosion, and then the primer and topcoat are applied in sequence.

[0040] 2. The epoxy resin in this application provides good adhesion and forms a strong bond with the surface of the metal plate, so that the subsequent colored paint can be firmly attached to the metal plate; rutile titanium dioxide has good hiding power and can improve the chemical stability of the primer system, thereby enhancing the mechanical strength, corrosion resistance, adhesion, light resistance and weather resistance of the primer system; modified talc has good dispersibility and can act as a skeleton to improve the whiteness, water resistance and anti-permeability of the primer system.

[0041] 3. The polyester resin in this application has good film-forming properties, chemical corrosion resistance, plump paint film, thick layer and hard surface; propylene glycol methyl ether acetate is used as a diluent to help improve the transparency, flexibility and durability of the paint; unsaturated polyvalent fatty amine dispersants reduce the interfacial tension between solid-liquid and liquid-liquid, increase the dispersion of each component in the paint, and improve the stability and rheological properties of the paint layer; the antibacterial composition can inhibit bacterial growth, prevent fungal growth, and provide a long-lasting antibacterial effect, so that the paint has good antibacterial properties, thereby improving the antibacterial properties of the metal plate. DETAILED DESCRIPTION

[0042] The present application is further described in detail below with reference to the embodiments.

[0043] The raw materials used in the examples and comparative examples can all be obtained commercially.

[0044] Preparation example of antibacterial composition

[0045] Preparation Example 1-1

[0046] The preparation method of the antibacterial composition comprises the following steps:

[0047] (1) 1.2 kg of bamboo fiber was dispersed in 2 L of 12% citric acid and soaked for 25 min, washed with water, and then dispersed in 3 L of anhydrous ethanol and ultrasonicated for 2 h to obtain a mixture 1;

[0048] (2) Dispersing nanosilver in 1 L of Camphor Tree extract, stirring at 65° C. for 2 h, then adding the mixture to the mixture 1 obtained in step (1), and continuing stirring for 3 h to obtain mixture 2; the Camphor Tree extract is obtained by dissolving 0.3 kg of Camphor Tree powder in 1 L of water.

[0049] (3) Dispersing chitosan in 1.5 L of 18% acetic acid solution, then adding it to the mixture obtained in step (2), stirring at 85° C. for 2 h, filtering, and drying to obtain an antibacterial composition.

[0050] Among them, the mass ratio of bamboo fiber, nanosilver and chitosan is 0.3:1:0.07.

[0051] Preparation Example 1-2

[0052] The difference from Preparation Example 1-1 is that no nanosilver is added.

[0053] Preparation Examples 1-3

[0054] The difference from Preparation Example 1-1 is that the Cynanchum oxyphylla extract is not added.

[0055] Preparation Examples 1-4

[0056] The difference from Preparation Example 1-1 is that chitosan is not added.

[0057] Preparation Examples 1-5

[0058] The difference from Preparation Example 1-1 is that the mass ratio of bamboo fiber, nanosilver and chitosan is 0.6:1:0.09.

[0059] Preparation Examples 1-6

[0060] The difference from Preparation Example 1-1 is that the mass ratio of bamboo fiber, nanosilver and chitosan is 0.9:1:0.02.

[0061] Preparation example of modified talc

[0062] Preparation Example 2-1

[0063] The preparation method of modified talcum powder comprises the following steps:

[0064] (1) Grind 0.5 kg of talc powder to obtain a powder with a particle size of 20-30 nm, disperse the powder in 2 L of anhydrous ethanol, and stir for 2 h to obtain a mixture 1;

[0065] (2) adding γ-cyclodextrin to the mixture 1 obtained in step (1), and ultrasonicating at a temperature of 65° C. for 45 minutes to obtain a mixture 2;

[0066] (3) Adding hydroxypropyl methylcellulose to the mixture obtained in step (2), ultrasonically treating the mixture at 85° C. for 25 min to obtain modified talc.

[0067] Among them, the mass ratio of talc, γ-cyclodextrin and hydroxypropyl methylcellulose is 1:0.3:0.02.

[0068] Preparation Example 2-2

[0069] The difference from Preparation Example 2-1 is that γ-cyclodextrin was not added.

[0070] Preparation Example 2-3

[0071] The difference from Preparation Example 2-1 is that hydroxypropyl methylcellulose is not added.

[0072] Preparation Example 2-4

[0073] The difference from Preparation Example 2-1 is that the mass ratio of talc, γ-cyclodextrin and hydroxypropyl methylcellulose is 1:0.1:0.04.

[0074] Preparation Example 2-5

[0075] The difference from Preparation Example 2-1 is that the mass ratio of talc, γ-cyclodextrin and hydroxypropyl methylcellulose is 1:0.6:0.01.

[0076] Example

[0077] Example 1

[0078] A production process for low-temperature baking color plates, comprising the following steps:

[0079] (1) The metal plate was spray-cleaned with a degreasing solution at 65°C for 2 minutes, and then the surface of the metal plate was coated with a passivating agent and baked at 140°C for 25 seconds to obtain a treated metal plate;

[0080] (2) coating the metal plate treated in step (1) with a primer, and then drying and curing the metal plate at a temperature of 125° C. to obtain a metal plate with a surface-cured primer layer, wherein the primer components include, by weight, 40 kg of epoxy resin, 20 kg of rutile titanium dioxide, 8 kg of modified talc, 3 kg of leveling agent, 2 kg of silicone oil defoamer, 22 kg of n-butanol, and 7 kg of butylated melamine resin;

[0081] (3) spraying the metal plate treated in step (2) with colored paint, and then drying and curing it at a temperature of 115° C. to obtain a low-temperature baked colored plate;

[0082] By weight, the paint components include 45 kg of polyester resin, 15 kg of propylene glycol methyl ether acetate, 7 kg of unsaturated polyvalent fatty amine dispersant, 13 kg of pigment, 11 kg of ceramic powder, 2 kg of leveling agent, and 15 kg of antibacterial composition.

[0083] The pigment is titanium dioxide, the leveling agent is an organic silicon leveling agent, and the metal plate is an aluminum plate.

[0084] The degreasing solution is 0.2 kg of degreasing agent dissolved in water, and the mass ratio of degreasing agent to water is 1:3.

[0085] The passivator is 0.5 kg of passivator dissolved in water, and the mass ratio of the passivator to water is 1:4.

[0086] The unsaturated polyvalent fatty amine dispersant is a BYK dispersant.

[0087] The antibacterial composition was prepared according to Preparation Example 1-1; and the modified talc was prepared according to Preparation Example 2-1.

[0088] Example 2

[0089] A production process for low-temperature baking color plates, which differs from Example 1 in that, by weight, the primer components include 30 kg of epoxy resin, 15 kg of rutile titanium dioxide, 5 kg of modified talc, 2 kg of leveling agent, 1 kg of silicone oil defoamer, 25 kg of n-butanol, and 9 kg of butylated melamine resin;

[0090] By weight, the paint components include 40 kg of polyester resin, 10 kg of propylene glycol methyl ether acetate, 10 kg of unsaturated polyvalent fatty amine dispersant, 10 kg of pigment, 9 kg of ceramic powder, 1 kg of leveling agent, and 18 kg of antibacterial composition.

[0091] Example 3

[0092] A production process for low-temperature baking color plates, which differs from Example 1 in that, by weight, the primer components include 50 kg of epoxy resin, 25 kg of rutile titanium dioxide, 12 kg of modified talc, 5 kg of leveling agent, 3 kg of silicone oil defoamer, 18 kg of n-butanol, and 6 kg of butylated melamine resin;

[0093] By weight, the paint components include 50 kg of polyester resin, 20 kg of propylene glycol methyl ether acetate, 5 kg of unsaturated polyvalent fatty amine dispersant, 15 kg of pigment, 13 kg of ceramic powder, 2 kg of leveling agent, and 12 kg of antibacterial composition.

[0094] Example 4

[0095] A production process for low-temperature baking color plates, which differs from Example 1 in that the antibacterial composition is prepared according to Preparation Example 1-2.

[0096] Example 5

[0097] A production process for low-temperature baking color plates, which differs from Example 1 in that the antibacterial composition is prepared according to Preparation Examples 1-3.

[0098] Example 6

[0099] A production process for low-temperature baking color plates, which differs from Example 1 in that the antibacterial composition is prepared according to Preparation Examples 1-4.

[0100] Example 7

[0101] A production process for low-temperature baking color plates, which differs from Example 1 in that the antibacterial composition is prepared according to Preparation Examples 1-5.

[0102] Example 8

[0103] A production process for low-temperature baking color plates, which differs from Example 1 in that the antibacterial composition is prepared according to Preparation Examples 1-6.

[0104] Example 9

[0105] A production process for low-temperature baking color plates, which differs from Example 1 in that the modified talc powder is prepared according to Preparation Example 2-2.

[0106] Example 10

[0107] A production process for low-temperature baking color plates, which differs from Example 1 in that the modified talc powder is prepared according to Preparation Example 2-3.

[0108] Example 11

[0109] A production process for low-temperature baking color plates, which differs from Example 1 in that the modified talc powder is prepared according to Preparation Examples 2-4.

[0110] Example 12

[0111] A production process for low-temperature baking color plates, which differs from Example 1 in that the modified talc powder is prepared according to Preparation Examples 2-5.

[0112] Comparative Example

[0113] Comparative Example 1

[0114] A production process for low-temperature baking color plates, which differs from Example 1 in that, by weight, the primer components include 25 kg of epoxy resin, 10 kg of rutile titanium dioxide, 2 kg of modified talc, 1 kg of leveling agent, 0.5 kg of silicone oil defoamer, 12 kg of n-butanol, and 3 kg of butylated melamine resin;

[0115] By weight, the paint components include 35 kg of polyester resin, 4 kg of propylene glycol methyl ether acetate, 2 kg of unsaturated polyvalent fatty amine dispersant, 8 kg of pigment, 7 kg of ceramic powder, 0.5 kg of leveling agent, and 10 kg of antibacterial composition.

[0116] Comparative Example 2

[0117] A production process for low-temperature baking color plates, which differs from Example 1 in that, by weight, the primer components include 55 kg of epoxy resin, 30 kg of rutile titanium dioxide, 15 kg of modified talc, 8 kg of leveling agent, 6 kg of silicone oil defoamer, 28 kg of n-butanol, and 12 kg of butylated melamine resin;

[0118] By weight, the paint components include 55 kg of polyester resin, 25 kg of propylene glycol methyl ether acetate, 13 kg of unsaturated polyvalent fatty amine dispersant, 18 kg of pigment, 15 kg of ceramic powder, 3 kg of leveling agent, and 20 kg of antibacterial composition.

[0119] Comparative Example 3

[0120] A production process for low-temperature baking color plates, which differs from Example 1 in that modified talc is not added.

[0121] Comparative Example 4

[0122] A production process for low-temperature baking color plates, which differs from Example 1 in that an equal amount of talcum powder is used instead of modified talcum powder.

[0123] Comparative Example 5

[0124] A production process for low-temperature baking color plates, which differs from Example 1 in that no antibacterial composition is added.

[0125] Performance testing

[0126] The low-temperature baked color plates prepared in Examples 1-12 and Comparative Examples 1-5 were subjected to performance tests;

[0127] Antibacterial effect: The antibacterial performance test was carried out according to the antibacterial performance method in Appendix A of HG / T3950-2007 "Antibacterial Coatings". The inoculated bacteria were selected at a concentration of 1.7×10 6 CFU / mL of Escherichia coli (ATCC8739) and a concentration of 1.1×10 6 The inoculation volume was 0.1 mL for Staphylococcus aureus (ATCC6538P) with CFU / mL, and the colony count was detected after the topcoat layer was in contact with the test bacteria for 24 hours.

[0128] Adhesion: Tested according to GB / T1720-1989 "Determination of adhesion of paint films". Adhesion is divided into seven levels, with level one being the best and level seven being the worst.

[0129] Bending performance: Test according to GB / T232-2010 "Metallic Materials Bending Test Method", bend the specimen at an angle of 180°, and observe whether there is peeling or cracking in the horizontal and vertical directions.

[0130] Impact resistance: Tested in accordance with GB / T1732-2020 "Determination of impact resistance of paint films"; test results are shown in Table 1.

[0131] Table 1 Tests of Examples and Comparative Examples

[0132]

[0133]

[0134] The low-temperature baked color plates prepared in Examples 1-3, 7, and 11 of the present application have good antibacterial and antimicrobial effects and mechanical properties. Among them, the antibacterial effect of Example 1 on Escherichia coli is 0.08 CFU / cm 2 The antibacterial effect on Staphylococcus aureus is 0.05 CFU / cm 2 The adhesion reaches level 1, the bending performance is good, there is no peeling or cracking in the horizontal and vertical directions, the impact resistance is 82.8cm, and it has good impact resistance. The various raw material components cooperate with each other to improve the adhesion performance, mechanical strength and antibacterial properties of the color board.

[0135] In the preparation method of the antibacterial composition of Example 4, nanosilver is not added. As shown in Table 1, the adhesion, bending performance and impact strength of the color plate do not change significantly, but the antibacterial performance of the color plate changes significantly, and the antibacterial effect on Escherichia coli is 0.95 CFU / cm 2 The antibacterial effect on Staphylococcus aureus is 0.88 CFU / cm 2 , indicating that nanosilver has excellent antibacterial properties, a large specific surface area and high activity. It can interact with bacteria, viruses and other microorganisms, destroy their cell membrane structure, inhibit their growth and reproduction, and thus achieve an antibacterial effect.

[0136] In the preparation method of the antibacterial composition of Example 5, no extract of Camphor Tree Vine was added. As shown in Table 1, the adhesion, bending performance and impact strength of the color plate changed slightly, but the changes were not significant. However, the antibacterial performance of the color plate changed greatly, and the antibacterial effect on Escherichia coli was 0.74 CFU / cm 2 The antibacterial effect on Staphylococcus aureus is 0.60 CFU / cm 2 , indicating that the extract of Cynanchum wilfordii has broad-spectrum and high-efficiency antibacterial activity, and at the same time has good dispersion properties, which can improve the overall antibacterial properties and the dispersion properties of each component, thereby improving the comprehensive performance of the components.

[0137] In the preparation method of the antibacterial composition of Example 6, chitosan is not added. As shown in Table 1, the adhesion and bending properties of the color plate do not change much, but the antibacterial properties and impact resistance of the color plate change greatly. The antibacterial effect of Escherichia coli is 0.63 CFU / cm 2The antibacterial effect on Staphylococcus aureus is 0.51 CFU / cm 2 , the impact resistance is 72.3cm, indicating that chitosan has good film-forming properties. Chitosan and Camphor Tree Vine extract can be coated on the surface of bamboo fiber, increasing the adhesion between bamboo fiber and nano-silver, thereby improving the mechanical properties, antibacterial properties and chemical stability of bamboo fiber, which in turn helps to improve the corresponding properties of colored paint.

[0138] Example 8 changes the mass ratio of bamboo fiber, nanosilver and chitosan. As can be seen from Table 1, each test performance is better than Example 4 and Example 6, but worse than Examples 1-3 and Example 7, indicating that there is a synergistic effect between bamboo fiber, nanosilver and chitosan. Nanosilver is loaded on the surface of bamboo fiber, and chitosan can increase the adhesion between nanosilver and bamboo fiber, thereby improving the comprehensive properties of bamboo fiber such as mechanical properties, adhesion and antibacterial properties, thereby improving the corresponding properties of the color board.

[0139] In the preparation method of modified talc powder in Example 9, γ-cyclodextrin is not added. As shown in Table 1, the adhesion and bending properties of the color plate do not change much, but the antibacterial properties and impact resistance of the color plate change greatly. The antibacterial effect of Escherichia coli is 0.65 CFU / cm 2 The antibacterial effect on Staphylococcus aureus is 0.53 CFU / cm 2 , and the impact resistance is 70.1cm, indicating that γ-cyclodextrin has good chemical stability, antioxidant and bactericidal properties. Mixing with talc can improve the solubility and stability of talc, help to disperse the powder evenly, and thus improve the corresponding performance of subsequent primers.

[0140] In the preparation method of modified talc powder in Example 10, hydroxypropyl methylcellulose is not added. As shown in Table 1, the adhesion and bending properties of the color plate do not change much, but the antibacterial properties and impact resistance of the color plate change greatly. The antibacterial effect of Escherichia coli is 0.67 CFU / cm 2 The antibacterial effect on Staphylococcus aureus is 0.55 CFU / cm 2 , and the impact resistance is 71.2cm, indicating that hydroxypropyl methylcellulose has thickening, bonding, dispersing, emulsifying and film-forming properties, so that talc and γ-cyclodextrin are not only mixed evenly, but can also coat talc. In the subsequent application of talc in primer, it can increase the film-forming property of the primer components and make the components mixed evenly.

[0141] Example 12 changes the mass ratio of talc, γ-cyclodextrin and hydroxypropyl methylcellulose. As can be seen from Table 1, each test performance is better than Examples 9-10, but worse than Examples 1-3 and Example 11, indicating that there is a synergistic effect between talc, γ-cyclodextrin and hydroxypropyl methylcellulose. γ-cyclodextrin increases the mechanical properties, adhesion and antibacterial properties of talc. Hydroxypropyl methylcellulose makes talc and γ-cyclodextrin mix evenly, increases the adhesion between talc and γ-cyclodextrin, and helps to change the antibacterial properties, mechanical properties and adhesion of talc, thereby improving the corresponding performance of the color plate.

[0142] Comparative Example 1-2 changes the raw material ratio of the primer component and the raw material ratio of the color paint component. As shown in Table 1, the antibacterial effect on Escherichia coli is about 1.52 CFU / cm 2 The antibacterial effect on Staphylococcus aureus is about 1.48 CFU / cm 2 , the adhesion reaches level 2, in the bending performance, there is no peeling or cracking in the horizontal and vertical directions, and the impact resistance is 60.2cm. It can be seen that the antibacterial performance, adhesion, bending performance and impact resistance of the color board are significantly deteriorated, indicating that the raw material components cooperate with each other, and the proportion of each raw material component is within a certain range, which can achieve better comprehensive performance.

[0143] In comparative example 3, modified talc was not added to the primer. As shown in Table 1, the antibacterial effect on Escherichia coli was 2.67 CFU / cm 2 The antibacterial effect on Staphylococcus aureus is 2.63 CFU / cm 2 The adhesion reaches level 2. In the bending performance, there is peeling and cracking in the horizontal and vertical directions. The impact resistance is 50.1cm, which shows that the modified talc powder has good dispersibility and can play a skeleton role, improving the adhesion, antibacterial properties, mechanical properties and mechanical strength of the primer system, thereby improving the corresponding performance of the primer.

[0144] In the comparative example 4, an equal amount of talcum powder was used instead of modified talcum powder in the primer. As shown in Table 1, the antibacterial effect on Escherichia coli was 1.84 CFU / cm 2 The antibacterial effect on Staphylococcus aureus is 1.82 CFU / cm 2 The adhesion reaches level 2. In the bending performance, there is peeling and cracking in the horizontal and vertical directions. The impact resistance is 55.6cm, indicating that the modified talc powder prepared in this application has better comprehensive properties such as antibacterial properties, adhesion and mechanical properties, thereby improving the corresponding performance of the primer.

[0145] In comparative example 5, no antibacterial composition was added to the paint. As shown in Table 1, the antibacterial effect on Escherichia coli was 3.21 CFU / cm 2 The antibacterial effect on Staphylococcus aureus is 3.16 CFU / cm 2The adhesion reaches level 2. In the bending performance, there is peeling and cracking in the horizontal and vertical directions. The impact resistance is 52.7 cm, which shows that the antibacterial composition can not only inhibit the growth of bacteria, prevent the growth of fungi, and provide a lasting antibacterial effect, so that the color paint has better antibacterial properties, thereby improving the antibacterial properties of the metal plate, but also improve the mechanical properties and adhesion of the color paint, which is conducive to better bonding between the color paint and the primer.

[0146] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A production process for low-temperature baking color plates, characterized in that: The steps include: (1) Use a degreasing solution to spray clean the metal plate at a temperature of 60-65°C for 1-2 minutes, then use a passivating agent to coat the surface of the metal plate, and bake it at a temperature of 140-145°C for 20-25 seconds to obtain a treated metal plate; (2) coating the metal plate treated in step (1) with a primer, and then drying and curing the metal plate at a temperature of 120-125° C. to obtain a metal plate with a surface-cured primer layer, wherein the primer components include epoxy resin, rutile titanium dioxide, modified talc, leveling agent, silicone oil defoamer, n-butanol, and butylated melamine resin; (3) spraying the metal plate treated in step (2) with colored paint, and then drying and curing it at a temperature of 110-115°C to obtain a low-temperature baked colored plate; The paint components include polyester resin, propylene glycol methyl ether acetate, unsaturated polyvalent fatty amine dispersant, pigment, ceramic powder, leveling agent, and antibacterial composition; The primer components include, by weight, 30-50 parts of epoxy resin, 15-25 parts of rutile titanium dioxide, 5-12 parts of modified talc, 2-5 parts of leveling agent, 1-3 parts of silicone oil defoamer, 18-25 parts of n-butanol, and 6-9 parts of butylated melamine resin; The paint components include, by weight, 40-50 parts of polyester resin, 10-20 parts of propylene glycol methyl ether acetate, 5-10 parts of unsaturated polyvalent fatty amine dispersant, 10-15 parts of pigment, 9-13 parts of ceramic powder, 1-2 parts of leveling agent, and 12-18 parts of antibacterial composition; The preparation method of the antibacterial composition comprises the following steps: (1) The bamboo fibers were dispersed in citric acid and soaked for 20-30 min, washed with water, and then dispersed in anhydrous ethanol and ultrasonicated for 1-2 h to obtain a mixture 1; (2) dispersing nanosilver in the extract of Camphor Tree Vine, stirring at a temperature of 60-70°C for 1-2 hours, and then adding it to the mixture 1 obtained in step (1), and continuing to stir for 2-4 hours to obtain the mixture 2; (3) Dispersing chitosan in acetic acid solution, then adding the mixture to the second mixture obtained in step (2), stirring at a temperature of 80-85°C for 1-2 hours, filtering, and drying to obtain an antibacterial composition; The mass ratio of the bamboo fiber, nanosilver and chitosan is 0.3-0.6:1:0.07-0.09; The preparation method of the modified talc powder comprises the following steps: (1) Grind talc powder to obtain a powder with a particle size of 20-30 nm, disperse the powder in anhydrous ethanol, and stir for 1-2 hours to obtain a mixture 1; (2) adding γ-cyclodextrin to the mixture 1 obtained in step (1), and ultrasonicating at a temperature of 60-65° C. for 30-45 minutes to obtain a mixture 2; (3) adding hydroxypropyl methylcellulose to the mixture obtained in step (2), and ultrasonically treating the mixture at a temperature of 80-85°C for 20-25 minutes to obtain modified talc; The mass ratio of the talc powder, gamma-cyclodextrin and hydroxypropyl methylcellulose is 1:0.1-0.3:0.02-0.

04.

2. The production process of a low-temperature baking color plate according to claim 1, characterized in that: The pigment is one or more of an organic pigment, a transparent pigment, a pearlescent pigment, a multi-angle effect pigment and a metallic pigment.

3. The production process of a low-temperature baking color plate according to claim 1, characterized in that: The leveling agent is one or a combination of organic silicon leveling agent, polyacrylate leveling agent and fluorine surfactant.

4. The production process of a low-temperature baking color plate according to claim 1, characterized in that: The metal plate is selected from one of an aluminum plate, an aluminum alloy plate, a tinplate plate, a hot-dip galvanized plate, an electro-galvanized plate, a stainless steel plate and a cold-rolled steel plate.

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