PMT-Stable Performance Through 230–240°C Baking Windows
Coil lacquer production demands matting agents that survive peak metal temperatures without colour shift or efficiency drop. GMATT 270 (d50 7–7.5 µm, wax-treated) is thermally stable through the full PMT 220–240°C baking window typical of NCCA polyester and PVDF lines. Batch-to-batch gloss repeatability is within ±1 GU at equivalent loading, allowing coil paint manufacturers to maintain strict colour and gloss specifications across production campaigns without reformulation.
Wax Treatment for Scratch Resistance at Recoiling Speed
High-speed recoiling on NCCA lines subjects the cured coil film to continuous tribological stress. The organic wax modification on GMATT 270 particles forms a boundary lubricant layer at the film surface, redistributing contact shear and eliminating micro-ploughing at particle edges. Compared to untreated silica grades, GMATT 270 delivers measurably higher scratch resistance — assessed by pencil hardness (H–2H) and Clemen scratch test — at the same 2.5–4.5 wt% loading, with no sacrifice of T-bend flexibility.
T-Bend Flexibility Without Micro-Cracking
The d50 7–7.5 µm particle size of GMATT 270 is selected to avoid stress concentrations within the 35–50 µm coil film matrix. Polyester coil topcoats formulated with GMATT 270 at standard loading pass T-1 to T-2 bend tests without cracking or delamination, fully supporting downstream post-forming, roll forming, and trapezoidal profile bending operations on pre-painted steel and aluminium.
FCL Supply with NCCA-Compatible Quality Documentation
Coil paint OEMs require supply chain reliability above all else. SEMITECH delivers FCL quantities (20 MT) of GMATT 270 with locked specification windows (d50, oil absorption, moisture, pH) and complete NCCA-compatible documentation per shipment: CoA, SDS, REACH compliance letter, and batch-traceable QC report. Private-label packaging is available. For OEM bulk rebrand of the same performance profile, see HMMAT 200 Series.
When to Use GMATT 270 for Coil Coatings
GMATT 270's balance of medium particle size, wax surface treatment, and thermal stability makes it the reference grade for polyester and PVDF coil topcoats in the 35–50 µm DFT range on NCCA lines.
| Scenario | Recommended Grade | Target DFT | Loading |
|---|---|---|---|
| Standard polyester coil topcoat | GMATT 270 | 35–50 µm | 2.5–4.5 wt% |
| PVDF architectural facade panel | GMATT 270 | 25–40 µm | 2.0–3.5 wt% |
| Thin-film PE coil, high clarity | GMATT 255 / 260 | 15–25 µm | 2.0–3.0 wt% |
| Heavy polyester coil primer | GMATT 285 / 290 | 40–60 µm | 3.5–5.5 wt% |
Technical FAQ
Coil coating formulation specifics for GMATT 270 and the GMATT 200 Series.
+Which GMATT grade is recommended for PVDF coil coating at PMT 230°C?
GMATT 270 (d50 7–7.5 µm, wax-treated) is the primary grade for PVDF and polyester coil coatings baked at PMT 220–240°C. Its wax surface remains thermally stable through the full baking window, delivering consistent 60° gloss targets of 15–35 GU without yellowing or efficiency loss. Loading is typically 2.5–4.5 wt% in 35–50 µm DFT coil topcoats.
+How does GMATT 270 wax treatment improve scratch resistance on NCCA recoiling lines?
The organic wax coating on GMATT 270 particles acts as a boundary lubricant at the cured film surface. During high-speed recoiling on NCCA lines, continuous metal-to-coating contact generates shear stress; the wax layer redistributes this stress and prevents micro-ploughing of the silica particle edges into the film matrix. This provides measurably higher scratch resistance versus untreated grades at equivalent loadings.
+What T-bend performance is achievable with GMATT 270 in coil polyester systems?
Coil polyester lacquers formulated with GMATT 270 at 2.5–4.5 wt% routinely pass T-1 to T-2 bend tests without film cracking or delamination. The d50 7–7.5 µm particle size avoids stress concentrations in the 35–50 µm film matrix, preserving elasticity needed for post-forming operations including roll forming and trapezoidal profile bending.
+Does GMATT 270 comply with NCCA standard documentation requirements?
Yes. SEMITECH provides full NCCA-compatible documentation with each shipment: Certificate of Analysis (CoA) with d50, oil absorption, and moisture content; Safety Data Sheet (SDS); REACH registration letter; and batch-traceable QC report. For PVDF architectural facade panel specifications, additional fluoropolymer compatibility test data is available on request.
+What is the gloss target range achievable with GMATT 270 in polyester coil topcoat?
With GMATT 270 at 2.0–4.5 wt% in polyester coil topcoat at 35–50 µm DFT, formulators can reliably achieve 60° gloss targets from 15 GU (deep matte) to 40 GU (satin), depending on loading and binder-to-pigment ratio. Gloss uniformity across a production run is within ±2 GU when particle size is held to d50 7.0 ±0.5 µm.
Recommended Solution
For polyester and PVDF coil coating lines running at PMT 220–240°C, specify GMATT 200 Series — wax-treated silica with proven thermal stability, T-bend flexibility, and NCCA-compatible supply documentation.
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