Acid-resistant animal husbandry color-coated plate and manufacturing method thereof

Abstract

The present invention belongs to the technical field of color-coated steel sheets, and specifically relates to an acid-resistant color-coated sheet for animal husbandry and a manufacturing method thereof. The color-coated sheet comprises a color-coated substrate, a passivation layer, a front coating, and a back coating. The coating of the color-coated substrate is a hot-dip galvanized aluminum-magnesium coating containing 4.5-15% Al, 0.1-1.6% Si, 1.0-2.3% Mg, and the remainder being Zn and unavoidable impurities; the coating weight is 60-275g / m 2 The passivation layer is a chromate passivation layer with a single-side weight of 15-35 mg / m 2 The primer resin contains 10%-15% epoxy resin E-03, 30%-35% epoxy resin E-20, and 20%-25% blocked isocyanate; the topcoat resin contains 25%-30% polyester resin, 30%-35% high-methyl etherified imino resin, and 0.8%-1.5% butylated melamine resin. This invention improves the livestock color-coated plate's resistance to C4 and C5 corrosion environments.

Description

Technical Field

[0001] The invention belongs to the technical field of color-coated steel plates, and in particular relates to an acid-resistant animal husbandry color-coated plate and a manufacturing method thereof. Background Art

[0002] Livestock coated steel plate is a new type of steel plate specifically designed for modern farms (such as those for pigs, cattle, and poultry), feed processing plants, and slaughterhouses. With the continuous development of the livestock industry, the demand for livestock farming facilities is increasing, placing higher demands on the performance of steel plates. Due to the unique operating environment of livestock farms, livestock coated steel plates must possess excellent corrosion and chemical resistance. In livestock farms, animal excretions are highly acidic or alkaline, volatile, and corrosive. Intensive farming also requires rigorous disinfection of the environment. For example, piggery lanes require strict disinfection with high-concentration disinfectant sprays. The livestock farming environment is highly oxidizing and corrosive. Therefore, livestock color-coated steel plates must effectively resist these corrosive factors during long-term use, ensuring that the surface coating does not blister, peel, or rust, thereby extending the service life of livestock pens and ensuring the stability and safety of livestock farming facilities.

[0003] Currently, the traditional livestock industry primarily uses standard architectural color-coated steel sheets, but their performance indicators fail to meet the actual needs of the livestock industry. In terms of corrosion resistance, the best SST cross-scratch corrosion spread distance for existing architectural color-coated steel sheets after 250 hours is 3.5mm, and after 500 hours, the SST cross-scratch corrosion spread distance is over 12mm, far below the requirements for livestock color-coated steel sheets: a corrosion spread distance of ≤2mm after 250 hours and ≤3mm after 500 hours. In terms of chemical resistance, such as sulfuric acid resistance, the coating on standard architectural color-coated steel sheets typically begins to blister or peel after 48 hours, while the chemical resistance required for livestock color-coated steel sheets is at least 300 hours, resulting in a significant performance gap. These issues seriously impact the service life of livestock pens and the stability of breeding facilities. Therefore, there is an urgent need for high-quality, specialized livestock color-coated steel sheets that possess both excellent corrosion resistance and chemical resistance to meet the development needs of the modern livestock industry. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides an acid-resistant animal husbandry color-coated plate and a manufacturing method thereof, targeting the acidic environment of pig farms, so as to meet the requirements of use in the acidic environment of pig farms.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0006] The present invention provides an acid-resistant animal husbandry color-coated steel plate, comprising a color-coated substrate, a passivation layer, a front coating and a back coating, wherein the front coating is composed of a primer combined with a topcoat layer, and the back coating is composed of a single primer layer or a primer layer combined with a topcoat layer. The invention is characterized in that the coating of the color-coated substrate is a hot-dip galvanized aluminum-magnesium coating, which comprises, by mass percentage, 4.5%-15% Al, 0.1%-1.6% Si, 1.0%-2.3% Mg, and the remainder being Zn and unavoidable impurities; the coating weight is 60 g / m 2 -275g / m 2 ;

[0007] The passivation layer is a chromate passivation layer with a single-side weight of 15 mg / m 2 -35 mg / m 2 ;

[0008] The primer of the front coating or back coating includes a primer resin, a diluent, and a pigment and filler. The primer resin includes epoxy resin E-03, epoxy resin E-20, and blocked isocyanate. In terms of mass percentage, the epoxy resin E-03 is 10%-15%, the epoxy resin E-20 is 30%-35%, the blocked isocyanate is 20%-25%, and the rest is the diluent and pigment and filler.

[0009] The topcoat of the front coating or the back coating includes a topcoat resin, a diluent and pigments and fillers. The topcoat resin includes a polyester resin, a high-methylated imino resin and a butylated melamine resin. In terms of mass percentage, the polyester resin is 20%-25%, the high-methylated imino resin is 30%-35%, the butylated melamine resin is 0.8%-1.5%, and the rest are diluents and pigments and fillers.

[0010] In the above technical solution, further, the coating weight is 100 g / m 2 -150g / m 2 .

[0011] In the above technical solution, further, the components of the chromate passivation layer include Na2CrO4 and water-based silicone resin.

[0012] In the above technical solution, further, the preparation process of the acid-resistant animal husbandry color coated steel plate includes: pre-treatment of the color coated substrate, passivation, primer and topcoat coating and baking;

[0013] In the primer and topcoat coating process, the particle size of the pigment and filler of the primer is 1 μm-1.5 μm; the particle size of the pigment and filler of the topcoat is 1 μm-2 μm.

[0014] In the above technical solution, further, the thickness of the primer film is 5μm-6μm, the thickness of the topcoat film is 18μm-25μm; the viscosity of the primer is 50s-70s, and the viscosity of the topcoat is 60s-80s.

[0015] In the above technical solution, further, in the passivation process, a water-based chromate passivation liquid is coated on the surface of the color-coated substrate, the drying temperature is 170-190°C, and the temperature is cooled to below 40°C.

[0016] In the above technical solution, further, in the baking process, the baking temperature is 216°C-232°C.

[0017] The present invention also provides the use of the aforementioned acid-resistant animal husbandry color-coated steel plate as a building panel material for pig farms.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention adopts a low-aluminum-zinc-aluminum-magnesium coating substrate and a specific magnesium content range, so that the color-coated plate forms a dense protective film (white rust) composed of zinc hydroxide, alkaline zinc chloride and magnesium hydroxide during the corrosion process, gradually covering the exposed incision metal, separating the external corrosive medium from the exposed metal substrate, thereby preventing further corrosion of the exposed incision; and on this basis, by selecting an epoxy modified primer and a high-density polyester topcoat, the corrosion resistance and chemical resistance of the color-coated plate coating are significantly improved; the above-mentioned two are tightly combined through a passivation layer of a specific thickness (weight), thereby maximizing the corrosion resistance of the livestock color-coated plate to C4 and C5 (pig farm) corrosion environments.

[0020] The color-coated plate of the present invention meets the requirement of ≤3mm in the SST corrosion spreading distance after 500 hours, and under acidic conditions, such as 10% H2SO4, 10% HAc, there is no blistering or falling off after 400 hours; and there is no change or blistering under 10% sodium hypochlorite for 400 hours. DETAILED DESCRIPTION

[0021] The present invention is further described below with reference to specific examples, but is not intended to limit the present invention in any way.

[0022] During the color plate manufacturing process, the degreasing and surface conditioning of the substrate are all carried out under the same conditions, and then the parameters specified in the following examples are controlled to produce livestock color plates, and finally the performance is tested.

[0023] The preparation process of the color-coated steel plate in the following embodiment includes the following steps:

[0024] (1) Pretreatment: The hot-dip galvanized aluminum-magnesium steel plate is used as the substrate, and the coating alloy composition is Al 10%, Si 1.2%, Mg1.0-2.3%, and the rest is Zn and inevitable impurities. The strip is fed through the uncoiler and sent to the pretreatment section through the tensioner. The surface of the strip is pretreated to improve the adhesion of the plate surface. The surface pretreatment is degreasing and cleaning;

[0025] (2) Passivation: After pretreatment, the strip enters the chemical coating machine, where a layer of water-based chromate passivation solution (containing Na2CrO4 and water-based silicone resin, the passivation solution is purchased directly from commercial sources) is coated on the surface of the strip. After exiting the chemical coating machine, it enters the drying furnace for drying at 180°C. The strip is cooled to below 40°C to form a passivation layer.

[0026] (3) Paint coating: After passivation, the strip is primed on the front side. The grinding particle size of the pigment filler of the primer is controlled at 1.5 microns, and the paint film thickness is 6 microns. The grinding particle size of the pigment filler of the front side topcoat is controlled at 2 microns, and the paint film thickness is 20 microns. The back side is coated with epoxy primer, and the paint film thickness is 6 microns. The second coating is consistent with the front side topcoat. The diluent used in the primer or topcoat can be a conventional diluent such as methylbenzene or isophorone to control the viscosity of the primer to 60s and the viscosity of the topcoat to 70s.

[0027] (4) Baking: The baking plate temperature is controlled at 224℃. The strip steel after being taken out of the oven enters the water quenching tank for cooling and then is dried. Finally, the strip steel passes through the inspection table and the exit shear, and is cut into the required coil weight to obtain the acid-resistant color plate for livestock breeding.

[0028] The polyester resin used in the following examples is 385 saturated polyester resin. Epoxy resin E-03, epoxy resin E-20, blocked isocyanate, high-methylated imino resin, butylated melamine resin, and 385 saturated polyester resin are all commercially available. The following examples all utilize the above-described preparation process to produce color-coated steel sheets with varying coating magnesium content, coating weight, passivation layer weight per side, and primer and topcoat resin ratios, and their performance is tested.

[0029] Example 1:

[0030] The coating has a magnesium content of 1.2% and a weight of 150g / m 2 ; Passivation layer single side weight 15mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 15%, 35% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 25%, 30% and 1.0% respectively.

[0031] Example 2:

[0032] The coating has a magnesium content of 1.5% and a weight of 120g / m 2 ; Passivation layer single side weight 25mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 12%, 35% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 25%, 35% and 1.2% respectively.

[0033] Example 3:

[0034] The coating has a magnesium content of 1.7% and a weight of 200g / m 2 ; Passivation layer single side weight 15mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 10%, 30% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 25%, 30% and 0.8% respectively.

[0035] Example 4:

[0036] The coating has a magnesium content of 1.8% and a weight of 150g / m 2 ; Passivation layer single side weight 30mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 13%, 30% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 30%, 30% and 1.2% respectively.

[0037] Example 5:

[0038] The coating has a magnesium content of 2.0% and a weight of 150g / m 2 ; Passivation layer single side weight 25mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 15%, 30% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 25%, 30% and 0.8% respectively.

[0039] Comparative Example 1

[0040] The coating has a magnesium content of 2.6% and a weight of 150g / m 2 ; Passivation layer single side weight 30mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 13%, 30% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 30%, 30% and 1.2% respectively.

[0041] Comparative Example 2

[0042] The coating has a magnesium content of 1.0% and a weight of 150g / m 2 ; Passivation film weight 12mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 13%, 30% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 30%, 30% and 1.2% respectively.

[0043] Comparative Example 3

[0044] The coating has a magnesium content of 1.8% and a weight of 150g / m 2 ; Passivation film weight 12mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 13%, 30% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 30%, 30% and 1.2% respectively.

[0045] Comparative Example 4

[0046] The coating has a magnesium content of 1.0% and a weight of 150g / m 2 ; Passivation film weight 30mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 13%, 30% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 30%, 30% and 1.2% respectively.

[0047] Comparative Example 5

[0048] The coating has a magnesium content of 1.8% and a weight of 150g / m 2 ; Passivation film weight 30mg / m 2 The mass percentages of primer resins E-03, E-20 and blocked isocyanate are 13%, 30% and 20% respectively; the mass percentages of topcoat resin polyester resin plus high methyl etherified imino resin and butyl etherified melamine resin are 35%, 25% and 1.8% respectively.

[0049] The performance of the above examples and comparative examples are shown in Table 1.

[0050] Table 1

[0051]

[0052] The color-coated sheet prepared in Example 4 exhibited the best impact, T-bend, salt spray corrosion resistance, and chemical resistance. However, in Comparative Example 1, increasing the magnesium content in the coating did not significantly improve corrosion resistance. In Comparative Example 2, reducing the magnesium content and the weight of the passivation layer significantly affected the corrosion resistance of the color-coated sheet. In Comparative Example 5, the coating's toughness decreased, and cracks and paint peeling occurred easily during bending, resulting in poor overall performance.

[0053] Anyone skilled in the art will be able to utilize the above-disclosed technical content to make many possible changes and modifications to the technical solution of the present invention, or to modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention that do not depart from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An acid-resistant color-coated plate for animal husbandry, comprising a color-coated substrate, a passivation layer, a front coating, and a back coating, wherein the front coating is composed of a primer combined with a topcoat layer, and the back coating is a single primer layer or a primer layer combined with a topcoat layer, characterized in that: The coating of the color-coated substrate is a hot-dip galvanized aluminum-magnesium coating, which includes, by mass percentage, 4.5%-15% Al, 0.1%-1.6% Si, 1.8% Mg, and the rest is Zn and unavoidable impurities; the coating weight is 60g / m 2 -275g / m 2 ; The passivation layer is a chromate passivation layer with a single-side weight of 30 mg / m 2 ; The primer of the front coating or back coating includes a primer resin, a diluent, and a pigment and filler. The primer resin includes epoxy resin E-03, epoxy resin E-20, and blocked isocyanate. In terms of mass percentage, the epoxy resin E-03 comprises 10%-15%, the epoxy resin E-20 comprises 30%-35%, the blocked isocyanate comprises 20%-25%, and the rest comprises diluent and pigment and filler. The topcoat of the front coating or the back coating includes a topcoat resin, a diluent and pigments and fillers. The topcoat resin includes a polyester resin, a high-methylated imino resin and a butylated melamine resin. In terms of mass percentage, the polyester resin is 25%-30%, the high-methylated imino resin is 30%-35%, the butylated melamine resin is 0.8%-1.5%, and the rest are diluents and pigments and fillers.

2. The acid-resistant animal husbandry color-coated plate according to claim 1, characterized in that: The components of the chromate passivation layer include Na2CrO4 and water-based silicone resin.

3. The acid-resistant animal husbandry color-coated plate according to claim 1, characterized in that: The preparation process of acid-resistant livestock color-coated steel plate includes: pre-treatment of color-coated substrate, passivation, primer and topcoat coating and baking; In the primer and topcoat coating process, the particle size of the pigment and filler of the primer is 1 μm-1.5 μm; the particle size of the pigment and filler of the topcoat is 1-2 μm.

4. The acid-resistant animal husbandry color-coated plate according to claim 3, characterized in that: The thickness of the primer film is 5 μm-6 μm, and the thickness of the topcoat film is 18 μm-25 μm; The viscosity of the primer is 50s-70s, and the viscosity of the topcoat is 60s-80s.

5. The acid-resistant animal husbandry color-coated plate according to claim 3, characterized in that: In the passivation process, a water-based chromate passivation solution is applied to the surface of the color-coated substrate, dried at a temperature of 170°C-190°C, and cooled to below 40°C.

6. The acid-resistant animal husbandry color-coated plate according to claim 3, characterized in that: During the baking process, the baking temperature is 216°C-232°C.

7. Use of the acid-resistant animal husbandry color-coated plate according to any one of claims 1 to 6 as a building panel material for pig farms.

Images