In the field of architectural decoration, the ability to recreate the surface of a material directly affects the efficiency of spatial iteration. Traditionally, PVC wallboards are considered "unprocessable" materials due to the surface coating process, but in fact, their substrates have unique coating compatibility.
Based on ASTM D7234 "Standard for Adhesion Test of Coatings on Rigid PVC Substrates", combined with the interface theory of polymer materials, this article systematically deconstructs the feasibility and technical points of coated PVC wallboards.
Polyvinyl chloride resin powder (50-60%): provides the main skeleton of the molecular chain and determines the rigidity of the material
Calcium carbonate (25-35%): functional filler, adjusts the coefficient of thermal expansion (CTE≤6×10⁻⁵/℃)
Stabilizer (3-5%): organic tin complex, inhibits thermal decomposition during processing
Plasticizer (DOP, 5-8%): reduces glass transition temperature (Tg≈80℃)
Processing aid (ACR, 1-2%): improves melt fluidity
Surface energy: 34-38mN/m (need to be confirmed by dyne pen test)
Polarity value: SP value is about 9.6 (cal/cm³)¹/²
Micromorphology: SEM observation shows 5-15μm concave and convex structures
Hot-press the decorative film to the substrate at 160-180℃, 0.1-0.3mm dense protective layer
Surface closed-pore rate>95%, coating strength reduced to level 0 (GB/T 9286 grid method)
Use cold pasting technology to composite 0.5mm thick PVC film (including UV coating)
Surface contact angle>110°, coating penetration<3%
The surface porosity of the untreated substrate is about 12%, which is suitable for paint penetration and anchoring
After plasma treatment, the surface energy can be increased to 52mN/m
Substrate status | Paintability | Technical requirements |
Thermal transfer processing board | No | Mechanical grinding to the substrate layer is required |
PVC coated board | No | Peeling off the coating will damage the structural integrity |
Base material | Yes | Direct surface pretreatment |
Alkaline washing: 5% NaOH solution scrubbing to remove release agent
Physical roughening: 240 mesh sandpaper polishing (surface roughness Ra = 2.5-3.2μm)
Plasma activation: 40kHz high-frequency treatment to improve surface polarity
Chloroether modified primer (solid content ≥ 45%, special for PVC)
Film thickness control: 15-20μm (too thick can easily lead to stress cracking ）
Drying conditions: forced drying in an oven at 60℃ for 30 minutes
Two-component polyurethane topcoat (NCO: OH=1.1:1)
Cross-spraying method (gun distance 25cm, air pressure 0.4MPa)
Total film thickness 80-100μm, film formation in 3 times
Stage 1: 25℃ surface drying for 30 minutes
Stage 2: 70℃ heating curing for 2 hours
Stage 3: Natural curing for 72 hours (RH≤60%)
Achieve special effects such as gradient and metallic texture (not possible with traditional laminating processes)
Support any Pantone color-matching on-site
Local repair costs reduced by 80% (compared with replacement of the entire board)
Renovation cycle shortened from 5 years to 2 years
Water-based paint replaces solvent-based lamination, reducing VOC emissions by 70%
Repainting old boards, extending material life by 200%
Experimental data show (refer to ISO 2409 standard) that the coating adhesion of the exposed PVC board substrate after scientific treatment can reach level 1 (cross-cut method) and the abrasion resistance is >5000 times (Taber abrasion tester). It is recommended to give priority to the coating scheme in the following scenarios:
Art installation wall: special texture expression is required
Historical building renovation: matching the original decorative color
Commercial space pop-up store: high-frequency visual update
Special note: The weather resistance of the PVC wall panel after painting will be restricted by the performance of the coating. It is recommended to test the coating yellowing index (ΔE≤3) every year and carry out maintenance and painting on time.
