KW-8073 SCA-Modified Polyester Resin
KW-8073 is an "anti-sag modified polyester resin." By introducing a "sag control agent" (SCA), it gives the resin new performance characteristics — improving rheology and anti-sag resistance, and enhancing both film performance and appearance. It is widely used in high-performance coatings, particularly suited for metallic flake coatings in automotive OEM and refinish paints. It has good compatibility with CAB, promotes directional alignment of aluminum/silver flakes, and enhances the metallic effect.
Especially recommended for metallic flake coatings, helping to:
- Improve interlayer adhesion
- Assist flake alignment
- Prevent flake settling
- Improve storage stability
Silver Base Formulation:
| Raw Material | Amount | Description |
|---|---|---|
| YZ-H304 | 24 | Low-hydroxyl acrylic resin |
| KW-8073 or competitor product | 10 | SCA-modified saturated polyester |
| 20% CAB531-1 | 15 | CAB solution in BAC |
| 15% CAB381-20 | 20 | CAB solution in BAC |
| SN-9461 | 13 | EVA wax paste, for flake alignment |
| SN-9021 | 4 | Polyethylene wax paste, anti-settling |
| BCS | 4 | Solvent |
| BAC | 9.6 | Solvent |
| 10% SN-4323 | 0.3 | Leveling agent |
| SN-6241 | 0.1 | Defoamer |
| Total | 100 |
Silver Metallic Paint Formulation:
| Raw Material | Amount | Description |
|---|---|---|
| Aluminum/silver paste | 8.5 | |
| BAC | 8.5 | Solvent |
| SN-2311 | 0.1 | Wetting/dispersing agent |
| Note: the above portion is for soaking the silver paste | ||
| Silver base | 82.9 | |
| Total | 100 | |
Test performance: Interlayer adhesion comparison between silver metallic base and clear coat
Test substrate: Tinplate
Silver metallic paint sprayed, air-dried for 20 minutes, then clear coat applied, baked at 80°C for 30 minutes, cross-hatch adhesion test:
Test results:
- With pure low-hydroxyl acrylic + CAB silver paste: large-area peeling of the top clear coat, indicating interlayer adhesion problems
- With competitor product: interlayer adhesion between silver base and clear coat is acceptable
- With KW-8073: interlayer adhesion between silver base and clear coat is excellent
Test focus: Whiteness test (higher whiteness indicates better flake alignment)
Test substrate: Test card & tinplate
Draw-down application:
Test results: Whiteness KW-8073 ≥ competitor > pure low-hydroxyl acrylic + CAB silver paste
Spray application (silver base + clear top coat):
Test results: Whiteness KW-8073 ≥ competitor
Test focus: Mottling/flooding effect (observed from the side); better flake alignment results in lighter or no mottling on the panel.
Test substrate: Tinplate
Spray application of silver metallic paint + clear top coat:
Test results: Viewed from the side, panels with pure low-hydroxyl acrylic + CAB silver paint show severe mottling; competitor panels show slight mottling; KW-8073 panels show almost no mottling.
Test focus: Discoloration (darkening) after heat storage and draw-down
Test substrate: Test card
Comparison of freshly prepared silver paint vs. paint heat-stored at 50°C for 14 days, draw-down comparison:
Test results: Silver paint prepared with pure low-hydroxyl acrylic + CAB shows significant darkening after heat storage; competitor product shows slight darkening; KW-8073 shows no darkening at all, demonstrating excellent heat storage stability.
KW-8073 SCA-modified polyester resin is especially suitable for metallic flake coatings. With good CAB compatibility, it improves interlayer adhesion, promotes directional alignment of aluminum/silver flakes, prevents flake settling, and delivers excellent storage stability.