Physical and chemical architecture and the technological genesis of the Printech coating
To fully understand the reasons for the extreme durability and phenomenal market popularity of this building material, it is necessary to detail its complex multilayer morphology. The decorative polymer coating is by no means created by a primitive single-layer painting or sticking a regular film. This is an extremely complex multi-stage process of sequentially applying functional chemical layers, each of which performs a strictly defined physical, chemical, or optical role. The total thickness of the decorative and protective complex is about 30-35 microns (µm), which forms a reliable shield over the steel core.
The technological cycle of coil sheet production according to the Printech standard includes the following high-precision stages and corresponding structural layers, applied under strict temperature control conditions at metallurgical plants.
The base load-bearing element is a high-quality cold-rolled steel sheet (mostly of the international DX51D grade), the thickness of which varies from 0.38 to 0.5 millimeters. The cold rolling process provides the metal with the necessary structural homogeneity and plasticity, which is a critically important parameter for subsequent mechanical profiling. This plasticity ensures that when bending the metal into corrugated board or facade panels like metal siding, microcracks, which could become centers of corrosion, will not occur in the crystal lattice of the steel.
On this steel core, the first critically important anti-corrosion metal layer is applied — a zinc or innovative aluzinc coating. Depending on the manufacturer, the geography of the metal’s origin, and the product class, the zinc content can vary significantly in the range from 40 to 275 grams per square meter. For example, premium South Korean Dongbu Steel is often supplied with a galvanizing rate of 225-275 g/m² (or a modern highly resistant magnesium-zinc alloy of 120/275 g/m²), which provides maximum cathodic protection for the steel, capable of performing without signs of through corrosion for many decades. At the same time, budget analogs, mainly of Chinese or Indian production, may have a much lower zinc content at the level of 40-140 g/m², which proportionally reduces their durability in a humid climate.
After thorough degreasing and chemical passivation (chromating) of the galvanized surface, a primer layer not less than 5 microns thick is applied to it. This microscopic but fundamentally important polymer interlayer provides ultra-high adhesion between the metal base and the subsequent colored polymer masses. In addition, the primer acts as an additional chemical barrier sealing the zinc layer from the impact of oxygen and moisture.
Next, a base coating approximately 15-20 microns thick is applied. This is a colored substrate serving as an even background for the future pattern. It determines the overall color temperature (warmth or coolness of the shade) of the finished product and has high adhesive properties for securely fixing the paints.
The key stage that directly forms the unique appearance of the product is the application of the decorative pattern. This process is carried out using the photo-offset (gravure) printing method. The surface of real natural materials — a cut of an oak board, masonry, or brick — is pre-photographed at ultra-high resolution, after which, using special high-precision printing rollers, this image is transferred to the base polymer coating.
Alternatively, to achieve unprecedented texture depth, a related vacuum sublimation technology is used. The principle of sublimation on metal consists of transferring an image from a decorative film to the working surface during the intensive evaporation of pigments. A special film with a pattern is superimposed on the metal, after which the air is pumped out from the gap between the film and the material, providing a perfectly tight fit. Under the influence of thermal treatment, the dye particles transition into a gaseous state, deeply penetrating into the structure of the paint base. Both of these methods — classic offset printing and vacuum sublimation — guarantee the photographic accuracy of imitating natural textures with a quality unattainable by traditional painting methods.
The final, finishing stage is the application of an outer transparent film that seals and protects the pigment from the destructive effects of ultraviolet radiation, abrasive wear, chemical reagents, and micro-scratches. Most often, a specialized polyester (PE) or high-tech polyvinylidene fluoride (PVDF / PDVF) is used for this purpose. A polymer coating made of PVDF up to 35 microns thick (which is 10 microns more than standard polyester) is considered the most modern and durable solution in today’s metallurgical market, capable of withstanding extreme climate loads without losing its optical properties.
Table 1. Typical microscopic structure of a steel sheet using Printech technology
| Layer number | Chemical component / Name | Approximate thickness / mass | Fundamental function in the system |
| 1 | Steel core (mostly DX51D) | 0.38 – 0.50 millimeters | Providing absolute mechanical strength, necessary spatial rigidity, and the capacity for cold profiling. |
| 2 | Zinc (or aluzinc) layer | 40 – 275 g/m² (double-sided) | Sacrificial (cathodic) anti-corrosion protection capable of self-healing in places of microscopic scratches or cuts. |
| 3 | Passivating and primer layer | ~ 5 microns (µm) | Neutralization of oxidation and providing cohesive strength between the metal crystal lattice and organic polymers. |
| 4 | Base polymer coating | 15 – 20 microns (µm) | Formation of a base background color and preparation of a perfectly flat surface for uniform paint absorption. |
| 5 | Offset or sublimation printing | Micron pigment layer | Creating a photorealistic texture that ensures identical visual characteristics to natural wood or stone. |
| 6 | Protective clear polymer (PE / PVDF) | 10 – 35 microns (µm) | Protection of the pattern from degradation under the influence of UV radiation, prevention of abrasive wear, and matrix waterproofing. |
Thanks to such an engineeringly complex, multilayer architecture, steel with a premium Printech coating becomes a full-fledged composite material that combines the load-bearing capacity of steel and the chemical inertness of modern polymers. The service life of such a material in real conditions often exceeds 35 years, and leading global manufacturers provide an official warranty from 10 years (for base polyester) to over 20 years (for PVDF coating).