Color-coated steel coil: a new force in coated steel with both functional and decorative properties

Color-coated coil (color-coated steel coil) refers to a coil product made of metal coil (such as cold-rolled steel plate, galvanized steel plate, aluminum-zinc alloy plate, etc.) as the substrate, after surface pretreatment (degreasing, phosphating, passivation), coated with one or more layers of organic coating (such as polyester, fluorocarbon, etc.), and then baked and cured. It combines the strength of metal with the decorativeness and corrosion resistance of coatings. With the advantage of "one material for multiple uses", it has become the preferred material in the fields of construction, home appliances, transportation, etc.
1. Classification and core characteristics of color-coated coils
The performance difference of color-coated coils is mainly determined by the type of substrate and the coating system, and different categories are suitable for different scenarios.
1. Classification by substrate type
The substrate is the "skeleton" of the color-coated coil, which directly affects its mechanical properties and basic corrosion resistance:

Cold-rolled substrate color-coated coil: With cold-rolled steel plate as the substrate, it has a smooth surface and high dimensional accuracy, but its corrosion resistance depends on coating protection. It is suitable for indoor environments (such as home appliance housings and furniture panels) and should not be exposed to outdoor humid or highly corrosive environments for a long time.
Hot-dip galvanized substrate color-coated coil: The substrate is a hot-dip galvanized steel plate (the zinc layer thickness is usually 50-275g/m²). The zinc layer and the coating form a "double protection", and the corrosion resistance is significantly improved. It is suitable for outdoor buildings (such as factory walls and roofs), light steel structures, etc., especially in rainy and humid areas.
Aluminum-zinc alloy substrate color-coated coil: The substrate contains aluminum (55%), zinc (43.4%) and a small amount of silicon (1.6%), forming a dense oxide layer. The corrosion resistance is better than that of hot-dip galvanized substrate (the service life can reach 2-3 times that of hot-dip galvanizing), and the reflectivity is high (energy saving), which is suitable for high-end buildings (such as commercial complex roofs, landmark building exterior walls) and high corrosion environments (such as coastal areas).
2. Classification by coating system
The coating is the "outer coat" of the color-coated coil, which determines its decorativeness, weather resistance and functionality:

Polyester (PE) coated color-coated coil: high cost performance, good gloss, rich colors (customizable matte, high gloss, metallic colors, etc.), medium weather resistance (outdoor life 5-10 years), suitable for general indoor and outdoor scenes (such as ordinary factory walls, home appliance shells).
Fluorocarbon (PVDF) coated color-coated coil: with fluorocarbon resin as the main component, it has excellent UV resistance, acid and alkali resistance, and aging resistance (outdoor life of more than 20 years), strong color stability, suitable for high-end buildings (such as airports, office building exterior walls), coastal areas or areas with severe industrial pollution.
Silicon modified polyester (SMP) coated color-coated coil: between PE and PVDF, better weather resistance than PE (outdoor life 10-15 years), lower cost than PVDF, suitable for scenes with certain requirements for weather resistance but limited budget (such as roofs and walls of schools and hospitals).
Special functional coating color coated coils: such as antibacterial coatings (adding antibacterial agents, used in food factories and hospital walls), self-cleaning coatings (surface hydrophobic and antifouling, reducing maintenance), thermal insulation coatings (reflecting heat and reducing building energy consumption), etc., to meet the needs of subdivided fields.
Summary of core features
Decorative: more than a thousand colors and textures (wood grain, stone grain, metal brushing, etc.) can be customized to replace traditional decorative materials (such as tiles, wood) to enhance the appearance texture.
Corrosion resistance: The coating and the substrate work together to resist corrosion from the atmosphere, rain, acid and alkali, etc., and reduce maintenance costs.
Processability: It can be cut, bent, stamped, and welded to meet complex modeling requirements (such as special-shaped roofs of buildings and curved shells of home appliances).
Lightweight: lighter than stone and concrete, reducing the load on building structures and shortening the construction period.
2. Production technology and innovation direction of color coated coils
The production of color coated coils is a combination of "metal processing" and "coating chemicals". The core technology lies in the adhesion and performance stability of the coating. In recent years, innovation has focused on "environmental protection" and "high performance".
1. Core production process
Substrate pretreatment: Degreasing to remove oil stains, phosphating to form a conversion film (enhancing coating adhesion), and passivation to further improve corrosion resistance are key links to ensure coating quality (poor pretreatment will cause coating shedding and blistering).
Coating: The mainstream adopts roller coating process (high efficiency and uniform coating), and 1-2 layers are applied according to demand (primer improves adhesion, topcoat determines decorativeness and weather resistance). Some high-end products will add back paint (to prevent back corrosion).
Baking and curing: Baking in a 200-300℃ oven to cross-link and cure the coating to form a hard coating. The curing temperature and time directly affect the coating hardness, scratch resistance and other properties.
Post-processing: Cooling, trimming, coiling, and some products will be coated (to protect the surface from scratches).
2. Technological innovation trends
Environmentally friendly paint replacement: Traditional solvent-based paints contain VOC (volatile organic compounds), which pollute the environment. In recent years, the proportion of water-based paints (using water as a solvent, VOC emissions are reduced by more than 80%) and powder coatings (solvent-free, recyclable) has increased, especially in the EU, China and other regions with strict environmental regulations.
Coating performance upgrade: By adding nanomaterials (such as titanium dioxide and graphene), the coating's UV resistance and scratch resistance are improved (for example, after adding graphene to fluorocarbon coatings, the weathering life can be extended to more than 30 years); develop "self-healing" coatings (tiny scratches can heal automatically) to reduce maintenance costs.
Intelligent production: The coating thickness and color difference are monitored in real time through an online spectrometer, and the AI ​​algorithm adjusts the coating parameters to ensure consistent performance of each meter of coil; the digital twin technology is used to simulate the coating aging process under different environments and optimize the formula design.
III. Typical application areas of color-coated coils
Color-coated coils have penetrated into multiple industries with their dual attributes of "function + decoration" and have become an important choice to replace traditional materials.
1. Construction (accounting for more than 60%)
Roofs and walls: roofs and exterior walls of industrial plants, storage and logistics parks, and commercial complexes. For example, large warehouses use light-colored color-coated coils (high reflectivity) to reduce indoor temperature and air conditioning energy consumption; landmark buildings use customized color-coated coils to create a unique appearance (such as a science and technology park in Shanghai that uses gradient color-coated coil walls to become a city check-in point).
Fences and partitions: municipal engineering fences and building partitions are light and easy to install, and can be printed with promotional patterns, with both protection and advertising functions.
Modular buildings: walls and roofs of container-type houses and prefabricated houses. The weather resistance of color-coated coils can adapt to the changing outdoor environment, and they are light in weight and easy to transport and assemble.
2. Home appliances and home appliances
Home appliance shells: the side and back shells of refrigerators, washing machines, and air conditioners use electrogalvanized substrate color-coated coils (smooth surface), which are matched with matte coatings to enhance the texture, and are moisture-resistant (kitchen environment) and easy to clean.
Furniture and kitchenware: wardrobe door panels, dining table tops, cabinet panels, imitation wood grain color coated coils can replace solid wood, reducing costs by more than 30%, and are formaldehyde-free, moisture-resistant and moth-proof.
3. Transportation field
Containers and carriages: freight container side panels and refrigerated truck carriages use highly weather-resistant color coated coils (such as PVDF coatings) to resist the sun and rain during long-distance transportation; refrigerated trucks use heat-insulating color coated coils to reduce cold loss.
Auto parts: battery shells and interior decorative panels of new energy vehicles, lightweight color coated coils can reduce vehicle weight and increase driving range.
4. Special scenarios
Agriculture and animal husbandry: roofs of breeding greenhouses (corrosion resistance, light transmission adjustment), grain storage warehouse walls (moisture-proof, rat-proof).
Billboards and signs: large outdoor billboards, traffic signs, UV-resistant coatings ensure long-term clarity of patterns, and are wind-resistant and pressure-resistant (more durable than traditional acrylic).
IV. Market trends and industry challenges
1. Development momentum
Growing demand in emerging markets: Urbanization in Southeast Asia and Africa is accelerating, and industrial plants and residential construction are driving demand for color-coated coils (the global market size is expected to exceed 300 billion yuan in 2025).
Renovation of old buildings: A large number of old buildings in Europe and the United States are renovating their exterior walls, and color-coated coils are the preferred choice because of their convenient construction (no need to dismantle the original structure).
Material substitution bonus: There is a clear trend of replacing tiles (reducing construction waste), wood (protecting forest resources), and stone (reducing transportation costs), and policies support the application of green building materials.
2. Core challenges
Raw material fluctuations: The prices of substrates (steel plates, zinc ingots) and coatings (resins, pigments) are greatly affected by international bulk commodities, and companies are under great pressure to control costs (for example, the price of zinc will rise by 15% in 2024, driving the price of hot-dip galvanized substrate color-coated coils to rise by 8%).
Rising environmental protection costs: Environmental protection processes such as water-based coatings and chromium-free passivation have high initial investments (30% higher than traditional processes), and small and medium-sized enterprises are under great pressure to transform.
Homogeneous competition: There is overcapacity in low-end and mid-end products (such as ordinary PE coatings), and the price war is fierce, so it is necessary to transform to high-end (fluorocarbon, customization).
3. Future direction
High-end and customization: Focus on high weather resistance (more than 30 years) and functional (thermal insulation, antibacterial) products to meet the needs of high-end buildings and special industries; provide "color + texture + performance" fully customized services (such as customizing metal texture color-coated coils for luxury stores).
Circular economy: Develop recyclable color-coated coils (coatings and substrates are easy to separate), establish a recycling-recoating and reuse system for old coils, and reduce resource consumption.
Cross-border integration: Combined with the photovoltaic industry, develop "color-coated coils + solar panels" integrated roofs (power generation + waterproofing) to adapt to the trend of new energy buildings.

The development of color-coated coils from simple "anti-corrosion steel" to "multifunctional materials" not only reflects the refinement level of the steel industry, but also reflects the direction of change in the field of materials: "green, intelligent, and scenario-based". In the future, driven by both policies and technologies, color-coated steel sheets will continue to replace traditional materials and become the "face value" and "performance backbone" of modern industry and construction.