PU Adhesive for Fire Doors
Single-component, moisture-cure polyurethane adhesive (MPU-20) for laminating fire-door skins to fire-resistant cores — bonding steel, stainless and wood facings to perlite, rock wool, magnesium and calcium-silicate boards with a strong, fire-rated, formaldehyde-free bond.
A fire-rated adhesive built for the door line
PUGLUE MPU-20 is a single-component, moisture-cure polyurethane that bonds fire-door skins to fire-resistant cores with ≥15 MPa metal-to-metal strength — on board cores the substrate fails before the bond. It is surface-dry in under 1 hour, cures in 4–8 h, resists high and low temperatures, and carries GB 8624 fire, low-flame-spread, toluene-free and formaldehyde-free certification. After curing the glue line is insoluble and non-melting.
Bonds Every Door Skin to Every Core
One polyurethane adhesive laminates fire-door face sheets to the full range of fire-resistant cores — for steel, wooden and stainless fire doors.
Face / skin materials
- Galvanized & color steel plate
- Stainless steel sheet
- Steel-wood & wooden skins
- Aluminum alloy & copper
Core materials
- Expanded perlite board
- Rock wool & mineral wool
- Magnesium & calcium-silicate board
- Vermiculite slab, paper honeycomb, gypsum
Door types
- Steel fire doors
- Wooden fire doors
- Security / anti-theft doors
- Stainless & household doors
Types of Fire-Door Adhesive — and Which to Choose
Fire doors are assembled with several adhesive chemistries. PUGLUE’s single-component MPU-20 polyurethane is the choice for fire-rated, structural skin-to-core bonds.
| Adhesive type | Components | Best for | Notes |
|---|---|---|---|
| 1K PU (MPU-20) | Single-component | Fire-door skin-to-core lamination | Moisture-cure, ≥15 MPa, GB 8624 fire-rated, formaldehyde-free. PUGLUE core product. |
| Two-component PU | A + B | High-volume structural panels | Chemical cure, humidity-independent; needs metering. Available on request. |
| Neoprene / solvent contact | 1K | Quick tack, low-spec doors | Solvent-based; lower heat / aging resistance and higher VOC — not ideal for fire-rated cores. |
| Hot-melt (EVA) | 1K | Edge / trim bonding | Softens and re-melts with heat — not for fire-rated structural cores. |
For fire-rated skin-to-core bonds, plants run the single-component MPU-20 — tell us your skin and core and we’ll confirm the grade.
Where PUGLUE Fire-Door Adhesive Is Used
From steel fire-door lines to decorative fireproof board, MPU-20 bonds skins to cores across the fire-rated building-products industry.
Engineered Performance
Strong, fire-rated and clean — the profile fire-door lines require.
High bond ≥15 MPa
Metal-to-metal tensile strength ≥15 MPa; on board cores the core fails before the glue line.
Fire-rated
GB 8624-2006 type-tested, low-flame-spread report and smoke toxicity grade ZA1 (GB/T 20285-2006).
Toluene & formaldehyde-free
Certified free of added toluene and formaldehyde — suited to indoor air and green building.
Insoluble & heat-stable
Once moisture-cured the glue line is insoluble and non-melting, with high and low-temperature resistance.
How to Apply MPU-20
A simple single-component workflow — no mixing, cured by ambient moisture.
Clean the surface
Remove oil and dust from the skin and core surfaces to be bonded.
Apply single-side
Spread evenly with a toothed scraper, or single-side coat with a roll coater, at 120–160 g/m².
Composite & press
Lay up skin and core and press. To speed cure, spray a little water mist on the glue line first.
Cure
Surface-dry in ≤1 h, full cure in 4–8 h (adjustable). Clean tools with ethyl acetate.
Technical Parameters
Single-component MPU-20 polyurethane — datasheet values, customizable to your line.
| Property | Value |
|---|---|
| Type | MPU-20 single-component polyurethane (moisture-cure) |
| Appearance | Dark brown / tan viscous liquid |
| Density | 1.15 ± 0.05 g/cm³ |
| Viscosity | 8000–9000 mPa·s (adjustable) |
| Solid content | 94% |
| Coating weight | 120–160 g/m² |
| Surface-dry time | ≤1 h |
| Cure time | 4–8 h (adjustable) |
| Bond strength | Metal–metal ≥15 MPa; metal–non-metal: substrate fails first |
| Dilution / cleanup | Ethyl acetate |
| Packaging | 25 kg plastic drum / 200 kg iron drum |
Curing principle: single-component, cured by moisture in the air and on the bonded surface.
Coverage, Cure & Storage
Practical figures to plan your fire-door lamination run.
Coverage
Single glue line; tune to core porosity. Too little weakens the bond.
Surface dry
Handleable quickly; a light water mist on the glue line speeds cure.
Cure time
Full cure, adjustable to your line speed and press cycle.
Packaging
25 kg plastic drum and 200 kg iron drum. Keep sealed against moisture.
Certifications & Compliance
MPU-20 is type-tested to Chinese national fire and indoor-air standards — documentation available for export.
Fire performance
GB 8624-2006 type test (nine indicators meet the national standard) and a low-flame-spread test report.
Smoke toxicity
Smoke toxicity grade ZA1 to GB/T 20285-2006 — suitable for fire-safe doors.
Indoor-air safety
National coating-quality reports certify no added toluene and no added formaldehyde.
Cold-storage tested
Tested by the Ministry of Agriculture cold-storage & refrigeration equipment quality centre.
Structural strength
Metal-to-metal bond ≥15 MPa; on board cores the core fails before the bond.
Export documentation
TDS, certificates and test reports supplied for overseas fire-door plants.
A Manufacturer You Can Build On
A dedicated polyurethane adhesive manufacturer — not a trading reseller — supplying fire-door plants worldwide since 2010.
Consistent, tested quality
In-house QC on every lot so viscosity, cure speed and bond strength stay repeatable.
Full technical support
TDS, certificates, free trial samples and engineer support to match your skin, core and line speed.
OEM & private label
Manufacturer-direct pricing, your branding and stable supply for continuous production — no middleman.
Packaging, Samples & OEM Supply
Manufacturer-direct supply built around fire-door-plant procurement.
Packaging
25 kg plastic drum and 200 kg iron drum — trial quantities on request.
Free trial sample
Trial samples with full TDS so you can validate bond and cure before committing.
OEM / private label
Your brand, your spec — manufacturer-friendly MOQ and repeatable batches.
Global export
Export-ready documentation, certificates and logistics support.
Frequently Asked Questions
Fire-door adhesive (MPU-20) — technical answers for door manufacturers.
What adhesive is used to make fire doors?
A single-component moisture-cure polyurethane — PUGLUE MPU-20. It laminates steel, stainless and wood door skins to fire-resistant cores (perlite, rock wool, magnesium, calcium-silicate, vermiculite), with ≥15 MPa metal-to-metal strength and a fire-rated, formaldehyde-free glue line.
Is the adhesive fire-rated?
Yes. MPU-20 is type-tested to GB 8624-2006, carries a low-flame-spread report, and reaches smoke toxicity grade ZA1 under GB/T 20285-2006 — suitable for fire doors.
What door skins and cores does it bond?
Skins: galvanized / color steel, stainless steel, aluminum alloy, copper, and steel-wood / wooden facings. Cores: expanded perlite, rock wool, magnesium and calcium-silicate board, vermiculite slab, paper honeycomb and gypsum board.
Is it formaldehyde-free and toluene-free?
Yes — national coating-quality reports certify no added formaldehyde and no added toluene, so it suits indoor-air and green-building requirements.
How strong is the bond?
Metal-to-metal tensile strength is ≥15 MPa. On non-metal cores such as perlite or gypsum board, the core itself fails before the glue line.
How much adhesive do I need (coverage)?
Coating weight is 120–160 g/m² on a single side, tuned to core porosity. Too little weakens the bond; too much extends cure time.
How long is the surface-dry and full cure time?
Surface-dry in ≤1 hour and full cure in 4–8 hours (adjustable). A light water mist on the glue line accelerates the moisture cure.
How is it applied?
Clean off oil and dust, spread the glue single-side with a toothed scraper or roll coater, composite the skin and core and press. Tools clean up with ethyl acetate.
What is the shelf life and how should it be stored?
Store in an ordinary indoor warehouse. Because it is moisture-cure, reseal drums after use and keep them away from humidity; nitrogen-blanket for long-term storage.
Do you offer samples, TDS, certificates, MOQ and OEM?
Yes. We provide a full TDS, fire and indoor-air certificates, free samples, and OEM / private-label supply with manufacturer-friendly MOQs. Contact us for a quote matched to your door build.
The PUGLUE Grade for This Application
The matched adhesive grade for fire-door cores & facings.
PU Liquid Foam Adhesive for Fire Doors
Polyurethane liquid foam adhesive for bonding fire-door cores to steel, stainless, wood or aluminium facings — the matched grade for fire-door assembly.
View Product Details →Related Adhesives & Guides
Matched polyurethane adhesives and technical resources for door and panel plants.