Product Overview
Molecular weight is what separates it from SILZ-701: the long backbone builds coherent films and higher char on pyrolysis, converting toward SiCNO/SiCN or silica ceramics. Si-H sites remain available for hydrosilylation, and Si-N/Si-H bonds react with hydroxyl compounds for curing-agent and modification duty in phenolic, epoxy, alkyd and acrylic systems.
Cured coatings serve continuously at 350 °C (500 °C instantaneous); compounded with heat-resistant nanofillers they withstand direct flame and high-temperature airflow — thin-film protection measured in a 10 µm class.
Key Benefits
Film-grade molecular weight
>8×10⁴ backbone forms coherent, defect-tolerant thin films that low-MW silazanes cannot deliver.
350 °C continuous service
Cured films hold at 350 °C with 500 °C excursions; nanofiller-compounded systems resist direct flame erosion.
≥6H at ~10 µm
Hard, adherent (Grade 0) protection from a film thin enough for precision parts, springs and mesh.
Same Si-H toolbox
Hydrosilylation sites and hydroxyl reactivity carry over — one feedstock for coating, curing-agent and precursor work.
Typical Applications
- Si-C-N ceramic precursor
- Amine curing agent
- Heat/weather-resistance modifier for phenolic, epoxy, alkyd, acrylic resins
Solution guides: Ceramic Precursors & Advanced CeramicsResin, Rubber & Composite Modification
Technical Data
| Test Item | Performance Indicator | Test Method |
|---|---|---|
| Color & Appearance | Pale yellow to colorless transparent liquid | GB/T 1721-79 |
| Viscosity (Ford Cup 4) | 35–50 s | GB/T 1723-1993 |
| Purity | ≥95% | Q/YX 10-2023 |
| Solid Content (120 ± 2°C) | >98% | GB/T 1725-2007 |
| Density | 1.05 ± 0.01 g/mL | GB/T 6750-2007 |
| Relative Molecular Mass | >8×10⁴ | GB/T 27843-2011 |
| Pencil Hardness | ≥6H | GB/T 6739-2006 |
| Adhesion | Grade 0 | GB/T 9286-1998 |
| Salt Spray Resistance | >500 h | GB/T 10125-2021 |
| Reactive Groups | Si-H (methylhydrosilazane, high-MW) |
| Dilution | High viscosity — 50% dilution recommended before application |
| Theoretical Coverage | 12–28 m²/kg |
| Curing Temperature | 180–250 °C |
| Curing Time | 1 h |
| Dry Film Thickness | 10 ± 5 µm (keep ≤15 µm) |
| Working Time (after opening) | 24 h |
| Recommended Operating Temperature | -30 to 300 °C (continuous 350 °C, max 500 °C) |
| Thinner | Aromatics, esters, ethers |
| Flash Point | <22 °C (solvent) |
| Storage Temperature | 0–30 °C |
Values from the SILZ-702 technical data sheet. Complete TDS with test conditions available on request.
Curing & Processing Guidance
The varnish is supplied at 35–50 s (Ford Cup 4); dilute about 50% with aromatic, ester or ether solvents before spraying. Substrate preparation follows Sa 2.5 (minimum St 3, no mill scale), degreased and dry.
Apply one coat at 10 ± 5 µm dry film and keep it at or below 15 µm — over-thick precursor films crack as they densify. Diluted coverage runs 12–28 m²/kg.
Cure at 180–250 °C for about 1 hour. Opened material remains usable for 24 hours. For pyrolysis beyond cure — ceramic conversion work — atmosphere and ramp are application-specific; ask for our starting schedules.
Substrate Compatibility
Carbon steel, stainless steel, cast iron, aluminum alloy, titanium alloy, high-temperature alloy steel, glass-ceramics, ceramics and cement. Formulations are adjusted to substrate and thermal-cycling conditions — describe the part and duty cycle for a confirmed system.
SILZ-702 — Purchasing & Application FAQ
Where does SILZ-702 fit versus SILZ-350?
The two share molecular weight class, film data and cure window. SILZ-350 adds vinyl groups beside Si-H for self-contained crosslinking; SILZ-702 is pure methylhydrosilazane — the cleaner choice when your formulation supplies its own unsaturation or when straightforward Si-H chemistry is wanted.
Why is dilution recommended before spraying?
SILZ-702 ships as a high-viscosity varnish to maximize usable polymer content. Cutting roughly 50% with aromatic, ester or ether solvent brings it to spray viscosity and helps hold the thin 10 µm-class film that performs best.
Can SILZ-702 coatings take direct flame?
Neat films serve to 350 °C continuous / 500 °C instantaneous. For direct flame or high-temperature airflow erosion, use nanofiller-compounded systems built on SILZ-702 — we support the compounding design.
TDS / SDS / COA & Samples
Technical Data Sheet, Safety Data Sheet and batch Certificate of Analysis are available for SILZ-702, and a COA accompanies every shipment. Evaluation samples ship with starting-parameter guidance.
Packaging: Available in 1 kg, 2 kg, 5 kg and 25 kg pails. Store at 0–30 °C in the original sealed container.
SDS & batch COA on request · Reply within 1 business day.