Application of thermal insulation coating in color steel production line

Abstract

The invention belongs to the technical field of color steel production, and discloses an application method of a thermal insulation coating in a color steel production line. By optimizing the formulas of the primer, the back paint and the finish paint, adding the diatomite, the aerogel and other environment-friendly thermal insulation materials and adapting to the technological parameters of a color coating production line, efficient thermal insulation of the color steel base plate is achieved. The primer is mainly composed of epoxy-polyester resin and contains anti-rust raw materials; the back paint adopts epoxy-polyester resin and aerogel to synergistically enhance the thermal insulation performance; and the finishing paint realizes ultraviolet reflection cooling through polyester resin and a reflecting material (such as nano titanium dioxide). The total thickness of the coating is controllable (primer and back paint are larger than or equal to 150 microns, and finish paint is 10-50 microns), the hardness is larger than or equal to 3H, 3T bending resistance is achieved, ultraviolet aging resistance is larger than or equal to 500 hours, and salt spray resistance is achieved. The production line does not need to be transformed, environment friendliness (no harmful volatile matter) and economical efficiency are achieved, plant energy consumption is remarkably reduced, and the method is suitable for color steel products in the high-temperature southern environment, the severe-cold northern environment and the industrial corrosion environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of color steel production, and particularly relates to application of a heat-insulating and heat-preserving coating in a color steel production line, and more particularly to a technology for realizing heat-insulating and heat-preserving functions of a color steel substrate through optimization of a coating formula and adjustment of a production process. BACKGROUND

[0002] Color steel is a metal plate widely used in the fields of industry and construction, and is often used in scenes such as workshops and fences due to its light weight, high strength and easy processing characteristics. However, traditional color steel takes a metal substrate as a base material, and only realizes protection and decoration functions through coating of conventional coatings, and does not have significant heat-insulating and heat-preserving properties itself, which leads to obvious defects in actual use: in high-temperature southern regions or industrial workshops requiring constant temperature control, ordinary color steel is prone to cause indoor temperature to rise significantly due to its strong metal heat conduction, fast surface heat absorption and slow heat dissipation, thereby increasing air conditioning energy consumption; in northern winters, water vapor is prone to condense on the surface of color steel due to low temperature, and long-term use may cause rust or coating peeling, thereby affecting structural stability.

[0003] To solve the above problems, the prior art attempts to improve the performance of color steel by adding heat-insulating materials, but generally has the following deficiencies: first, traditional heat-insulating materials (such as ordinary fillers) have poor compatibility with coating systems, which easily leads to coating delamination and adhesion loss; second, the production process is complex, and cannot adapt to the high-speed production requirements of existing color coating production lines (such as production line speed needs to be stabilized at 100-170 meters / minute, and oven temperature needs to be controlled at 160-250 DEG C to realize rapid curing); and third, the existing improvement scheme does not fully consider the synergistic optimization of the coating formula and process parameters, and it is difficult to maintain the mechanical properties (such as hardness, bending resistance) and weather resistance (such as ultraviolet aging resistance, water and salt mist resistance) of color steel while ensuring the heat-insulating and heat-preserving effect. Therefore, it is urgent to develop a coating application technology that can adapt to the high-speed production of existing color coating production lines and realize efficient heat-insulating and heat-preserving through compounding of environmentally friendly materials. SUMMARY

[0004] The application belongs to the technical field of color steel production, and particularly relates to application of a heat-insulating and heat-preserving coating in a color steel production line, and more particularly to a technology for realizing heat-insulating and heat-preserving functions of a color steel substrate through optimization of a coating formula and adjustment of a production process.

[0005] In order to achieve the above object, the application is realized by the following technical scheme: application of a heat insulation coating to a color steel production line, comprising the following steps: adjusting the formula of the primer, back paint and topcoat for the color steel production line, adding an environmentally friendly thermal insulation material (such as diatomite, aerogel), and adapting the process parameters of the production line (production line speed 100-170 m / min, oven temperature 160-250 DEG C), so that the color steel substrate forms a composite coating with a total thickness of ≥ 150 μm (primer + back paint ≥ 150 μm, topcoat 10-50 μm, total thickness up to 110-300 μm), while meeting the comprehensive performance requirements of hardness ≥ 3H, 3T bending resistance, UV aging resistance ≥ 500 hours (preferably 800 hours), water resistance and salt spray resistance in line with national standards, thereby imparting the color steel substrate with efficient heat insulation and thermal insulation functions.

[0006] The core logic of the application is to achieve the heat insulation and thermal insulation function through the four-step synergy of "formula adjustment + process adaptation + thickness control + performance enhancement", covering the whole process from material selection to final performance verification.

[0007] As the core protection range of the patent, the overall technical scheme of the application is defined, emphasizing the combination of "adjusting the process parameters of the existing production line" and "adding environmentally friendly thermal insulation materials", highlighting the innovation point of "upgrading the function without modifying the production line".

[0008] Compatible with the high-speed production requirements (speed 100-170 m / min) of the existing color coating production line, reducing the cost of enterprise equipment modification; through the synergy of multi-layer coating (primer rust prevention + back paint thermal insulation + topcoat reflection), realizing the systematic improvement of the heat insulation and thermal insulation function; clearly defining the performance indicators (hardness, weather resistance, etc.), ensuring the balance of function and processing adaptability, durability.

[0009] Further, the primer is mainly composed of epoxy-polyester type environmentally friendly resin, adding rust-proof raw materials (such as zinc powder, phosphate) and diatomite; the back paint is mainly composed of epoxy-polyester type environmentally friendly resin; the topcoat is mainly composed of polyester type environmentally friendly resin, adding reflective thermal insulation materials (such as nano titanium dioxide, zinc oxide).

[0010] Refine the specific formula composition of each coating, clearly define the main resin type (epoxy-polyester, polyester), auxiliary ingredients (rust-proof raw materials, reflective materials) and environmental protection properties (no harmful volatile substances).

[0011] Limit the core material system of each coating to solve the technical problems of "insufficient adhesion of coating to color steel substrate" and "poor dispersibility of thermal insulation materials", ensuring the stability of the adhesion of the coating to the substrate and the thermal insulation performance.

[0012] The epoxy-polyester resin in the primer cooperates with zinc powder / phosphate to enhance the anti-rust performance (the pain point of traditional color steel prone to rust); the epoxy-polyester resin in the back paint cooperates with aerogel and diatomite to improve the heat insulation efficiency by utilizing the porous structure (thermal conductivity ≤0.02 W / (m·K)) of aerogel and the microporous adsorption of diatomite; the polyester resin in the topcoat combines with nano-sized reflective materials (particle size ≤50 nm) to reduce the surface temperature (measured temperature reduction of 5-8°C) by reflecting sunlight and ultraviolet rays (wavelength 280-400 nm), thereby achieving active heat insulation.

[0013] Further, the coating formulation adjustment method is to reduce the proportion of filling pigments (such as barium sulfate and kaolin) in the existing mature color coating formulation (from the conventional 30-40% to 10-15%), and replace part of the fillers with diatomite and reflective materials (replacement proportion ≥20%) to adapt to the existing production line process (such as controlling the coating viscosity at 2000-4000 mPa·s to avoid sagging or missing coating during roll coating).

[0014] The specific strategy of formulation adjustment is to balance the flowability and functionality of the coating by "reducing filling + increasing functional materials", and to determine the replacement proportion and process adaptation target (viscosity range).

[0015] The technical obstacle of "adding thermal insulation materials leading to high viscosity of the coating and being unable to adapt to the existing production line" is solved to ensure uniform film formation of the coating during high-speed roll coating.

[0016] Reducing the proportion of filling pigments can reduce the cost of the coating (the unit price of barium sulfate and kaolin is higher than that of diatomite); after replacing part of the fillers, the viscosity of the coating is maintained at 2000-4000 mPa·s (the conventional color coating viscosity range), avoiding uneven coating or equipment blockage caused by high viscosity; the addition of diatomite can improve the thixotropy (shear thinning property) of the coating, further optimizing the stability of the roll coating process.

[0017] Further, the production line process parameters include: production line speed 100-170 meters / minute (preferably 120-150 meters / minute), oven temperature 160-250°C (primer curing section 180-200°C, back paint curing section 210-230°C) to ensure rapid curing of the coating (surface dry time of single layer paint film ≤15 seconds, complete curing time ≤30 seconds, single layer paint film thickness ≤50 μm).

[0018] The specific subsection of process parameters (difference in curing temperature of primer / back paint) and curing effect (surface dry / complete curing time, single layer thickness limit) are determined.

[0019] The problem of "prolonged curing time of the coating after adding functional materials, which cannot match the high-speed production line" is solved to ensure continuous operation of the production line.

[0020] The primer curing section has a low temperature (180-200℃) to avoid damage and destruction of the microporous structure of diatomite (high temperature can cause the pores to collapse, reducing the thermal insulation performance); the back coating curing section has a high temperature (210-230℃) to promote the cross-linking reaction of the epoxy-polyester type environmentally friendly resin and aerogel and improve the compactness of the coating; and the single-layer coating thickness is ≤50μm to avoid "internal stress concentration" caused by an excessively thick coating and reduce the risk of coating cracking.

[0021] Further, the total thickness of the paint film of the color steel base plate should satisfy: primer (5-20μm) + back coating (50-100μm) ≥ 150μm, top coating (10-50μm), and the total thickness can reach 300μm (when special scenarios require enhanced thermal insulation, the total thickness can be increased to 200-300μm).

[0022] The thickness range of each coating and the scenario adaptability of the total thickness (regular scenarios and special scenarios) are refined.

[0023] The thickness is controlled to balance the thermal insulation efficiency and processing performance (such as the flexibility of the coating during punching and bending), to avoid poor thermal insulation due to insufficient thickness or processing difficulties due to excessive thickness.

[0024] The primer is 5-20μm, taking into account rust prevention and cost (excessive thinness can easily rust, and excessive thickness increases cost); the back coating is 50-100μm, utilizing the porous structure of aerogel and diatomite to form a "static air thermal insulation layer" (the thermal conductivity of air is 0.026W / (m·K), which is much lower than the thermal conductivity of the metal base plate); the top coating is 10-50μm, and the reflective material needs to be uniformly dispersed in the coating, and an excessively thin coating cannot effectively reflect ultraviolet light, and an excessively thick coating can increase the brittleness of the coating; and the total thickness of special scenarios is 200-300μm, which is suitable for use in cold northern regions or high-temperature and high-humidity workshops to further improve the thermal insulation performance.

[0025] Further, the paint film formed after the paint is cured should satisfy a hardness ≥ 3H (pencil hardness test) and a 3T bending performance (bending a steel rod with a radius of 3mm by 180° without cracks).

[0026] The specific test methods (pencil hardness, bending test) and standards (3H hardness, 3T bending without cracks) of the mechanical performance indicators are specified.

[0027] The problem of "functional coating falling off due to high brittleness during processing" is solved to ensure the integrity of the coating during subsequent processing such as punching and bending of the color steel.

[0028] Hardness ≥ 3H: Prevents the coating from falling off due to slight scratches (the hardness of traditional color steel coatings is mostly 2H-3H); 3T bending resistance: Meets the processing requirements of color steel in scenes such as building enclosures and factory ceilings (such as curling and overlapping); Balance of mechanical properties and thermal insulation properties: Through flexible filling of diatomaceous earth (particle size distribution 5-20μm) and elastic modification of polyester resin, the toughness of the coating is improved.

[0029] Furthermore, the paint film formed after the coating is cured must meet the requirements of UV aging resistance of ≥ 500 hours (ISO 4892-2 standard, irradiance 0.89W / (m 2 )·nm), preferably ≥800 hours (under accelerated aging conditions).

[0030] The international standard (ISO 4892-2) is quoted to clarify the test conditions and classification requirements for UV aging resistance (500 hours as the basis, 800 hours as the preferred).

[0031] Solve the problem of "outdoor color steel coating causing powdering and fading due to ultraviolet radiation" and extend the service life of color steel.

[0032] 500-hour aging resistance: meets the outdoor use needs of the southern region for 3-5 years (annual average UV exposure is about 100-200 hours); 800-hour aging resistance: suitable for areas with strong UV rays such as the northwest and plateau, extending the maintenance cycle of color-coated steel; synergistic effect of reflective materials: nano-scale reflective materials can reduce the surface temperature of the coating (≤60°C) and slow down the aging rate of the resin (the aging rate doubles for every 10°C increase in temperature).

[0033] Furthermore, the paint film formed after the coating is cured must meet water resistance (no blistering or falling off after immersion for 24 hours) and salt spray resistance (neutral salt spray test ≥1000 hours, GB / T10125-2021).

[0034] The national standard (GB / T 10125) is cited to clarify the salt spray resistance test conditions and indicators (≥1000 hours), and the specific requirements for water resistance are supplemented (no abnormalities after immersion for 24 hours).

[0035] Solve the problem of "coating failure of color-coated steel in industrial plants and coastal areas due to moisture and salt spray corrosion" and improve the weather resistance of the coating.

[0036] Water-resistant for 24 hours without abnormalities: prevents bulging of the coating caused by condensation water during the rainy season in the south or in humid workshops; salt spray resistance for 1000 hours: suitable for coastal industrial plants (such as shipyards and docks), the coating life is extended to more than 10 years in salt spray environment; auxiliary role of aerogel: the porous structure of aerogel can absorb a small amount of water vapor, reduce direct contact between water and metal substrate, and reduce the risk of electrochemical corrosion.

[0037] Further, the aerogel (particle size 10-50 μm, porosity ≥ 90%) in the back paint and the diatomite (particle size 5-20 μm, specific surface area ≥ 60 m 2 / g) synergistically work together to form a "double-effect thermal insulation layer" by the low thermal conductivity (≤0.02 W / (m·K)) of the aerogel and the microporous adsorption (volume expansion ≤5% after adsorbing water vapor) of the diatomite, thereby enhancing the thermal insulation performance (thermal conductivity ≤0.1 W / (m·K), reduced by 60-80% compared with traditional color steel) and the anti-dripping function (condensed water diffuses along the microporous structure after contacting the back paint, reducing dripping).

[0038] The specific parameters (particle size, porosity, specific surface area) of the aerogel and diatomite and the synergistic mechanism (low thermal conductivity + adsorption diffusion) are determined.

[0039] The problems of "limited thermal insulation effect of single insulation material" and "condensed water dripping leading to humid factory" are solved, and the dual functions of passive thermal insulation and active anti-dripping are realized.

[0040] The nanoscale pores (≤50 nm) of the aerogel can block air convection (gas thermal conductivity accounts for 80%), significantly reducing the thermal conductivity; the micropores (2-20 nm) of the diatomite can adsorb water vapor, reducing the surface humidity (relative humidity ≤60%), and reducing the generation of condensed water; after synergistic effect, the surface temperature of the back paint layer is reduced by 10-15°C (tested at noon in summer) compared with traditional color steel, and the indoor temperature of the factory is reduced by 3-5°C.

[0041] Further, the reflective thermal insulation material (such as nano-titanium dioxide with a particle size of 20-50 nm) in the topcoat can reduce heat absorption (surface heat flux density reduced by 40-60%) by reflecting sunlight ultraviolet rays (reflectivity ≥85%, wavelength 280-400 nm) and part of visible light (reflectivity ≥70%, wavelength 400-700 nm), thereby improving the thermal insulation efficiency of the color steel (surface temperature reduced by 8-12°C compared with color steel without reflective layer).

[0042] The specific type (nano-titanium dioxide), particle size range, and reflection performance index (ultraviolet reflectivity ≥85%, visible light ≥70%) of the reflective material are determined, and the improvement effect of the thermal insulation efficiency is quantified.

[0043] The problem of "passive insulation material cannot offset the heat input of solar radiation" is solved, and the heat absorption of the color steel surface is reduced by active reflection, realizing "double-directional thermal insulation".

[0044] Nanometer particle size (20-50nm) can be uniformly dispersed in polyester resin, avoid the uneven coating caused by agglomeration; UV reflectivity ≥85%: the proportion of ultraviolet rays in solar radiation is 5%, but the energy accounts for about 46%, which can greatly reduce the energy accumulation in the coating after reflection; Surface temperature reduction of 8-12℃: the measured data shows that the surface temperature of the coated color steel is 8-12℃ lower than that of ordinary color steel during 10:00-15:00 in summer, which significantly reduces the heat transfer to the room.

[0045] The advantages of the present application: the present application directly applies the heat insulation coating to the color steel production line by optimizing the coating formula and adapting the process parameters of the production line, which has the following remarkable advantages:

[0046] Functional integration: by adjusting the formula of primer, back paint and topcoat (adding diatomite, aerogel and other environmentally friendly thermal insulation materials, combined with reflective thermal insulation materials), the color steel substrate has multiple functions such as rust prevention, heat insulation, reflection and cooling, solving the single problem of traditional color steel relying on metal substrate protection.

[0047] Process adaptability: based on existing mature coating formula, reduce the proportion of filling pigment (such as barium sulfate, kaolin), replace part of the filler with diatomite and reflective material, without the need to greatly modify the production line equipment or add additional process steps (such as special curing link), which can directly adapt to the high-speed production demand of existing color coating production line (production line speed 100-170m / min, oven temperature 160-250℃), single layer paint film thickness ≤50μm can be quickly cured.

[0048] High efficiency of heat insulation: by controlling the total thickness of the paint film (primer + back paint ≥150μm, topcoat 10-50μm, total thickness up to 300μm), combined with the low thermal conductivity of diatomite and the porous heat preservation structure of aerogel, the heat transfer is effectively blocked; at the same time, the reflective thermal insulation material in the topcoat can reflect the ultraviolet rays of sunlight, realize surface cooling, further improve the heat insulation efficiency, and is suitable for multiple scene demands such as heat resistance in south and heat preservation in north.

[0049] Excellent mechanical properties: the hardness of the paint film formed after curing is ≥3H, and it can pass the 3T bending test, ensuring that the coating does not fall off or crack during punching, bending and other processing of color steel, balancing functionality and processing adaptability.

[0050] Outstanding weather resistance: the paint film can resist ultraviolet aging for ≥500 hours (preferably 800 hours), and the water and salt spray resistance meet the national standards, which can resist moisture, salt spray corrosion and sunlight for a long time in industrial environment, prolonging the service life of color steel.

[0051] Environmental safety: The coating system uses epoxy-polyester, epoxy-amino and polyester environmentally friendly resins. The added diatomite, aerogel and reflective materials are all environmentally friendly raw materials, without harmful volatile substances, meeting the green production requirements and reducing the impact on the environment and human health.

[0052] Synergistic effect: The aerogel and diatomite in the primer work synergistically to enhance the thermal insulation performance and reduce water droplet condensation through the porous structure. The reflective material in the topcoat combines with the polyester resin to achieve a balance between heat reflection and coating film formation, further improving the thermal insulation efficiency and coating stability. DETAILED DESCRIPTION

[0053] Example 1: Application of color steel thermal insulation in southern high-temperature factory buildings

[0054] Application scenario: Color steel roof of factory buildings in southern high-temperature areas during summer (environmental temperature ≥ 35℃, ultraviolet intensity ≥ 800μW / cm 2 ).

[0055] Implementation steps:

[0056] Coating formula adjustment:

[0057] Primer: Epoxy-polyester resin (60%) + zinc powder (15%) + (10%) + diatomite (10%) + anti-rust agent (5%).

[0058] Backcoat: Epoxy-polyester resin (55%) + aerogel (20%) + diatomite (15%).

[0059] Topcoat: Polyester resin (65%) + nano-titanium dioxide (15%) + zinc oxide (10%) + leveling agent (5%).

[0060] Process parameters: Production line speed: 150 meters / minute; Oven temperature: primer section 185℃, backcoat section 220℃. Single-layer paint film thickness: primer 15μm, backcoat 80μm, topcoat 30μm (total thickness 125μm).

[0061] Performance verification:

[0062] Thermal insulation effect: Surface temperature reduced by 12℃ compared to ordinary color steel, indoor temperature reduced by 4.5℃ (actual measurement data); Weather resistance: resistant to ultraviolet aging for 800 hours (ISO 4892-2), no powdering or discoloration.

[0063] Mechanical properties: hardness 3H, resistant to 3T bending without cracking.

[0064] Innovation: Through the synergistic effect of high-proportion aerogel (backcoat) and nano-titanium dioxide (topcoat), high-efficiency thermal insulation and reflective cooling are achieved, suitable for high-speed production lines.

[0065] Example 2: Color Steel Heat Preservation Application in Northern Cold Regions

[0066] Application Scenario: Low-temperature factory building in northern winter (ambient temperature ≤ -10℃, humidity ≥ 80% RH).

[0067] Implementation Steps:

[0068] Coating Formulation Adjustment:

[0069] Primer: Epoxy-polyester resin (55%) + rust inhibitor (20%) + diatomite (15%) + (10%).

[0070] Backcoat: Epoxy-polyester resin (50%) + aerogel (25%) + diatomite (15%).

[0071] Topcoat: Polyester resin (70%) + reflective material (10%) + hydrophobic agent (5%).

[0072] Process Parameters: Production line speed: 120 meters / minute; Oven temperature: primer section 190℃, backcoat section 215℃; Single-layer paint film thickness: primer 10μm, backcoat 100μm, topcoat 20μm (total thickness 130μm).

[0073] Performance Verification: Heat Preservation Performance: Thermal conductivity coefficient ≤ 0.08 W / (m·K), 75% lower than traditional color steel; Condensation water prevention: backcoat microporous structure adsorbs water vapor, condensation water contact angle ≥ 150°, reducing dripping; Salt spray resistance: passes GB / T 10125-2021 standard (1000 hours without rust) ; Innovation: Aerogel and diatomite synergistically form a static air layer, combined with a hydrophobic agent, solving the condensation water problem in northern low-temperature and high-humidity environments.

[0074] Example 3: Color Steel Rust Prevention and Heat Insulation Integration Application for Industrial Fences

[0075] Application Scenario: Metal fence in chemical plant area (requires acid mist corrosion prevention and mechanical processing resistance).

[0076] Implementation Steps:

[0077] Coating Formulation Adjustment:

[0078] Primer: Epoxy-polyester resin (60%) + zinc phosphate (15%) + (10%) + diatomite (10%) + rust inhibitor (5%).

[0079] Backcoat: Epoxy-polyester resin (50%) + aerogel (20%) + diatomite (15%).

[0080] Topcoat: Polyester resin (65%) + nano zinc oxide (15%) + wear-resistant agent (5%).

[0081] Process parameters: production line speed: 100 m / min; oven temperature: primer section 180°C, back paint section 210°C; single-layer paint film thickness: primer 20 μm, back paint 50 μm, topcoat 30 μm (total thickness 100 μm).

[0082] Performance verification: rust prevention: salt spray resistance 1200 hours (GB / T 10125), no blistering or peeling; wear resistance: resistant to 3T bending + sandpaper friction (500 cycles) without coating peeling; thermal insulation: surface temperature reduction 8°C, indoor temperature fluctuation ≤2°C; innovation: combining high adhesion primer (zinc phosphate) with wear-resistant topcoat to meet the rust prevention and mechanical processing needs of industrial fences.

[0083] Example 4: Application of color steel tile renovation thermal insulation system

[0084] Application scenario: renovation of old color steel tile factory (requires rapid construction).

[0085] Implementation steps:

[0086] Pre-treatment:

[0087] Surface treatment: sandblasting and rust removal (Sa2.5 level), application of rust conversion agent (to form a phosphating layer).

[0088] Coating formulation:

[0089] Renovation topcoat: polyester resin (70%) + aerogel (15%) + diatomite (10%) + reflective material (5%).

[0090] Process parameters: coating method: high-pressure airless spraying (film thickness control 50-80 μm); curing conditions: room temperature curing (25°C, 24h) or low-temperature baking (80°C, 1h).

[0091] Performance verification: construction efficiency: single spraying coverage ≥12 m² / kg, construction period shortened by 50%; thermal insulation performance: thermal conductivity coefficient ≤0.12 W / (m·K), energy consumption reduced by 40%; environmental friendliness: VOC content ≤50 g / L, meeting GB 30981-2020 standard; innovation: renovation topcoat integrates aerogel and reflective material, without the need to remove old coating, achieving rapid renovation and thermal insulation upgrade.

[0092] Example 5: Color steel corrosion prevention application in high-humidity coastal factory

[0093] Application scenario: color steel workshop in coastal shipyard (humidity ≥90%, high salt spray concentration).

[0094] Implementation steps:

[0095] Coating formulation adjustment:

[0096] Primer: Epoxy-polyester resin (50%) + zinc powder (25%) + (15%) + diatomite (10%).

[0097] Back-coat: Epoxy-polyester resin (45%) + aerogel (30%) + diatomite (15%).

[0098] Top-coat: Polyester resin (60%) + nano-titanium dioxide (20%) + mildewcide (5%).

[0099] Process parameters: Line speed: 130 m / min; Oven temperature: Primer section 185°C, back-coat section 220°C; Single-layer film thickness: Primer 15 μm, back-coat 70 μm, top-coat 25 μm (total thickness 110 μm).

[0100] Performance verification: Salt spray resistance: passed GB / T 10125-2021 (1000 hours without rust) ; Mildew resistance: mold growth grade ≤ 1 grade (GB / T 1741-2007); Thermal insulation: surface temperature reduced by 10°C, indoor humidity reduced to 55% RH; Innovation point: high proportion of aerogel (back-coat) and mildewcide synergies, solving the corrosion and mildew problem in high humidity and high salt environment.

[0101] Summary table of examples

[0102]

[0103]

[0104] Common innovation:

[0105] Environmental-friendly material compounding: Environmental-friendly materials such as diatomite and aerogel replace traditional fillers to reduce VOC emissions.

[0106] Process adaptability: By adjusting the viscosity of the coating (2000-4000 mPa·s) and the oven temperature (180-230°C), it is compatible with existing color coating production lines.

[0107] Functional synergy: The synergistic design of primer rust prevention, back-coat thermal insulation, and top-coat reflection realizes the integration of thermal insulation, rust prevention, and weather resistance.

[0108] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. Application of a thermal insulation coating in a color steel production line, characterized by: The following steps are involved: By adjusting the formula of primer, back paint and top paint used in the color steel production line, adding environmentally friendly thermal insulation materials (such as diatomaceous earth and aerogel), and adapting the production line process parameters, the color steel substrate can be given thermal insulation functions.

2. The application of a heat-insulating coating in a color-coated steel production line according to claim 1 is characterized in that: The primer is mainly made of epoxy-polyester environmentally friendly resin, with anti-rust raw materials, diatomaceous earth and aerogel added; the back paint is mainly made of epoxy-polyester environmentally friendly resin; the top paint is mainly made of polyester environmentally friendly resin, with reflective heat insulation material added.

3. The application of a heat-insulating coating in a color-coated steel production line according to claim 1 is characterized in that: The coating formula adjustment method is: reducing the proportion of filler pigments (such as barium sulfate and kaolin) in the existing mature formula, replacing part of the fillers with diatomaceous earth and reflective materials to adapt to the existing production line process.

4. The application of a heat-insulating coating in a color-coated steel production line according to claim 1 is characterized in that: The production line process parameters include: production line speed of 100-170 m / min, oven temperature of 160-250° C., to ensure rapid curing of the coating (single-layer paint film thickness ≤ 50 μm).

5. The application of a heat-insulating coating in a color-coated steel production line according to claim 1 is characterized in that: The total thickness of the paint film of the color steel substrate must meet the following requirements: primer + back paint ≥ 100 μm, top paint 10-50 μm, and the total thickness can reach 110-300 μm to achieve thermal insulation effect.

6. The application of a heat-insulating coating in a color-coated steel production line according to claim 1 is characterized in that: The paint film formed after the paint is cured must meet the requirements of hardness ≥ 3H and 3T bending resistance.

7. The application of a heat-insulating coating in a color-coated steel production line according to claim 1 is characterized in that: The paint film formed after the coating is cured must meet the requirement of UV aging resistance of ≥500 hours (preferably 800 hours).

8. The application of a heat-insulating coating in a color-coated steel production line according to claim 1 is characterized in that: The paint film formed after the coating is cured must meet the water resistance and salt spray resistance requirements of national standards.

9. The application of a heat-insulating coating in a color-coated steel production line according to claim 2, characterized in that: The aerogel in the back paint works synergistically with the diatomaceous earth to enhance the heat insulation and anti-drip functions.

10. The application of a heat-insulating coating in a color-coated steel production line according to claim 2, characterized in that: The reflective heat-insulating material in the topcoat achieves surface cooling by reflecting ultraviolet rays from the sun, thereby improving the heat-insulating efficiency of the color-coated steel.

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