Clear protection is the hardest coating brief: the film must defend the surface — scratches, weather, graffiti, grime — while pretending not to exist. Organic clearcoats yellow and chalk outdoors; hard inorganic treatments need furnace cures; wax-class repellents sacrifice themselves in months.
Room-temperature polysilazane clears close the gap. Covalent bonding to glass, metal and ceramic substrates carries pencil hardness from 4H to beyond 8H in an optically clean film that does not yellow — while hydrophobic surface chemistry (contact angles from 105° past 120°) makes water, grime, marker and spray paint release instead of grip.
Four grades ladder the trade-offs between hardness, repellency, endurance and cost — from maintenance-duty RT6 to the fluoro-modified anti-graffiti specialist RT8 — all curing ambient, all serviceable outdoors for years.
Service Conditions Covered
| Surface requirement | Optical transparency, non-yellowing outdoors; hardness 4H → >8H by grade; contact angle 105° → ≥120° |
| Temperature range | Continuous service from <150 °C (RT6) to 500 °C non-yellowing (RT7); cold rating to -50 °C (AAPSZ) |
| Substrates | Glass, metals, ceramics, glass-ceramics, PV glass, coated masonry and architectural surfaces |
| Film build | 20–200 µm single-coat windows by grade; one-pass application (cured surfaces repel recoats) |
| Curing options | Full ambient cure (hours to handling, days to full properties) or 150–180 °C accelerated schedules of 20–30 min |
Recommended Products & Why
| Grade | Format | Curing | Service Temp. | Why this grade |
|---|---|---|---|---|
| SILZ-RT7 | — | Surface dry 2 h · full cure >5 d | Non-yellowing to 500 °C long-term; short-term to 800 °C (substrate-dependent) | The hardness flagship: ≥8H, >110° repellency and 500 °C non-yellowing clarity — the ceiling of ambient-cured clear protection. |
| SILZ-RT8 | — | >24 h full cure (surface dry ~1.5 h) | -30 to 400 °C (500 °C instantaneous) | The anti-graffiti specialist: fluoro-modified ≥120° surface releases marker, paint and adhesives through repeated cleaning cycles at ≥6H. |
| SILZ-AAPSZ | One-component | Room temperature >24 h, or 150 °C <0.5 h | -50 to 280 °C (400 °C instantaneous) | The endurance clear: >2000 h salt spray, -50 °C cold rating and PV-glass pedigree — for marine, cold-climate and solar-adjacent duty. |
| SILZ-RT6 | — | Surface dry 2 h · full cure >5 d | <150 °C continuous; short-term to 800 °C (substrate-dependent) | The maintenance workhorse: ≥4H at the friendliest cost and the widest film window — repair, refurbishment and general outdoor protection. |
Format, curing and temperature values from each product's TDS.
Formulators building proprietary clear systems start from the SILZ-150 resin series — the same room-temperature polysilazane chemistry as neat feedstock (≥6H–7H capability, non-yellowing). See Organopolysilazane Resins; the coatings above are the ready-to-use expressions of that platform.
Surface Preparation & Application Principles
On glass and ceramics, preparation is cleaning discipline: fully degrease, remove silicone residues (they defeat wetting), and dry. On metals, the standard Sa 2.5 / St 3 profile applies before any clear system.
Plan one campaign per surface: cured films are hydrophobic and oleophobic by design, so they repel their own recoats. Reach target film in the single specified pass; for later repairs, abrade the repair zone to re-expose a bondable surface.
For anti-graffiti programs, define the cleaning protocol with the coating: solvent wipes matched to the film chemistry remove marker and paint without consuming the surface. Test-patch protocols and cleaner pairings ship with the TDS.
Applicability Boundaries & What We Confirm
- Hardness and repellency peak in different grades — no single clear maximizes both. Rank your spec before choosing (hardness → RT7; release → RT8; endurance/cold → AAPSZ).
- Transparent films show what they protect: substrate defects and corrosion staining remain visible. Surface quality going in defines appearance coming out.
- Anti-graffiti performance is intrinsic but not absolute: aged, deeply porous or previously painted masonry needs a validated test patch first.
- Optical applications (PV output, display glass) require transmittance validation on your specific substrate and film build — sample panels provided.
- What we confirm: leading surface property, substrate and its preparation state, outdoor exposure class, cleaning regime, and required film life.
Discuss your project with an engineer
Send your substrate, service conditions and current coating problem — we reply with a concrete system proposal within 1 business day.