Water-Based Transparent Friction-Control Topcoat
With global environmental regulations tightening — for example, the EU’s ban on PFOA-containing fluoropolymers (traditional friction-control materials) combined with domestic requirements for zero heavy-metal emissions — the coatings industry is shifting toward green, water-based technologies. At the same time, fastener applications (especially in the automotive industry) demand “precise and stable” friction coefficients. Under Germany’s VDA standard, screw friction coefficients must remain between 0.09 and 0.16 to suit automated tightening. Traditional coatings often fail to meet these criteria, showing wide friction variability, high baking energy consumption, and insufficient strength when paired with zinc-aluminum basecoats.
Against this backdrop, leveraging continuous innovation in water-based technology, Junhe developed a new transparent water-based topcoat that combines low baking temperature (energy savings), enhanced surface hardness and salt-spray resistance, and precise friction control. This formulation addresses the shortcomings of conventional products while enabling more efficient and environmentally friendly production in the fastener industry.
Zincover®9131
Water-Based Transparent Friction-Control Topcoat
Developed in-house by Junhe Technology, Zincover®9131 is a versatile water-based functional topcoat compatible with various basecoats and pretreatments, including Dacromet, Cr(VI)-free zinc-aluminum, and hot-dip galvanizing. It is widely used on fasteners and hardware components.
Key Advantages:
- Works with basecoats to resolve the low-strength issue of zinc-aluminum coatings (Dacromet/Cr-free zinc-aluminum).
- Simultaneously enhances surface hardness and salt-spray resistance.
- Provides stable, precisely controlled friction coefficients.
- Operates at ultra-low baking temperatures, reducing energy costs while boosting performance and lowering total cost.
Main Features
- High hardness and strength – excellent scratch, impact, and chip resistance.
- High penetration and dense sealing – effectively improves salt-spray performance; enhances corrosion protection when combined with basecoats.
- Controlled friction coefficient – 0.09–0.15 range.
- Excellent application properties – suitable for dip or spray coating; 1–3 µm dry-film thickness with low material usage and low operating cost.
Technical Parameters
| pH | 10±1 | Specific Gravity (25 °C) | 1.0±0.03g/ml |
| Solid Content (180 °C / 20 min) | 16±2% | Viscosity (Ford Cup #2) | Approx. 15 s |
Application Areas
- Coating of fasteners, hardware parts, wind-power components, photovoltaic components, and automotive parts.
- Can be applied together with zinc-aluminum micro-coatings, Dacromet basecoats, hot-dip galvanizing, electroplating, blackening, or directly on metal substrates.
Recommended Application Processes
Spray Coating:
Adjust dilution ratio according to the customer’s on-site conditions.
Dip Coating:
Recommended dilution ≥30%; spinning speed 210–270 rpm, immersion/spin time 10–20 s.
Curing/Baking Conditions:
80 °C for 15 min (part temperature) or room temperature for more than 2 hours.
Maintenance & Management
- Bath Replenishment:Prepare the coating at the required solids content; replenish if liquid level is low.
- If solids content is too high after analysis, dilute with water to the target concentration.
- If solids content is too low after analysis, add original solution to reach the target concentration.
- Filtration:Zinc powder or other impurities carried in by fasteners may cause surface defects. Filter regularly using a 50–100 mesh screen.
- pH Control:Maintain pH at 9–10. Deviations may cause precipitation and reduce bath life. Ensure parts are properly rinsed to avoid contamination of the coating bath.
Post time: Sep-16-2025