Direct Factory Supply · Model PU-40

PU-40 UV Resistant Polyurethane Roof & Facade Sealant

High-elasticity, low-modulus polyurethane sealant formulated specifically for exterior joints exposed to severe sunlight, thermal expansion, and weather cycling. Over-paintable, non-staining, and permanently flexible.

35 ± 5 A
Shore A Hardness

≤ 0.40 MPa
Tensile Modulus

±25%
Joint Movement

100%
Over-Paintable

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PU-40 Technical Data Sheet (Verified Parameters)

Laboratory tested physical properties and performance standards in strict accordance with ASTM C920 & ISO 8339 testing methodologies.

Technical Property	Standard / Test Method	CHEMPU PU-40 Verified Value	Engineering Significance
Chemical Base	Moisture-curing Polyurethane	1-Component PU Prepolymer	No on-site mixing required; cures with atmospheric moisture
Hardness (Shore A)	ISO 868 / ASTM D2240	35 ± 5 A	Medium-low hardness, absorbs vibration & thermal joint movement
Tensile Modulus (at 100%)	ISO 8339 / ASTM C1135	≤ 0.40 MPa	Low stress on joint edges; prevents substrate spalling
Tack-Free Time (23℃, 50% RH)	ASTM C679	≤ 180 min (approx. 2-3 hours)	Allows adequate tooling window without collecting dust
Curing Speed (23℃, 50% RH)	Internal Lab Standard	3 – 5 mm / 24 hours	Deep-curing formulation for 12-25mm joint depths
Elongation at Break	ISO 8339	≥ 500%	Exceptional stretch recovery under cyclic building expansion
Joint Movement Capability	ASTM C920 Class 25	± 25%	Meets international standard for exterior expansion joints
Service Temperature	Thermal Chamber Cycling	-40℃ to +80℃	Withstands frozen winter conditions and hot summer roofs
Standard Colors	Visual / Colorimeter	White, Grey, Black (Custom RAL matched)	Matches precast concrete, metal panels, and roofs

UV and Weather Resistance: Built for Direct Sunlight

Standard polyurethane sealants easily chalk and crack under solar UV radiation. PU-40 incorporates a specialized UV-stabilizer package to protect elongation and bond integrity.

Why Standard Polyurethane Fails Outdoors:

Surface Chalking & Micro-Cracks:

Generic PU breaks down under solar UV rays, forming micro-cracks that allow water intrusion.

✓

CHEMPU PU-40 Stabilized Formula:

Fortified with hindered amine light stabilizers (HALS). Retains >85% tensile elasticity in accelerated weathering tests.

✓

Zero Plasticizer Bleeding (Non-Staining):

Will not leach oils onto coated metal roof sheets or surrounding architectural stone panels.

PU-40 polyurethane sealant tensile elongation and recovery laboratory test

Laboratory Tensile Elongation & Weathering Chamber Inspection

Engineered for 4 Demanding Joint Scenarios

Specifically formulated for building envelopes where high cyclic movement and solar UV attack coincide.

Metal Roof Lap Joints

Seals corrugated metal laps, ridge caps, and flashings. Absorbs heavy thermal shifts without popping fastener seals.

Precast Facade Panel Seams

0.40 MPa low modulus cushions expansion seams between precast concrete panels without causing edge spalling.

Window Perimeter Sealing

Weatherproof exterior perimeter joints between aluminum frames and masonry with high tooling smoothness.

Exterior Expansion Joints

High elasticity for building expansion gaps that require subsequent over-painting to blend in seamlessly with walls.

Core Advantage vs Silicone

100% Paintable Without Surface Priming

Unlike silicone sealants, which completely reject architectural paints, CHEMPU PU-40 allows water-based acrylics and exterior masonry coatings to adhere directly onto the cured sealant bead.

🎨 Seamless Aesthetics: Paint over cured joint to match exact wall paint.
🛡️ Extra Protection: Paint coating acts as a sacrificial barrier against UV.
⏱️ Fast Recoat: Ready for over-coating after skin formation (approx. 24 hours).

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PU-40 concrete wall panel vertical joint caulking with paintable surface

Packaging, MOQ & 20GP Container Loading

Export-standard pallets, moisture-barrier shrink wrap, and full private label OEM capabilities for international distributors.

Package Format	Units / Carton	20GP Container Capacity
600 ml Foil Sausage (Standard)	20 pcs / ctn	1,200 cartons (24,000 pcs)
310 ml Aluminum Cartridge	24 pcs / ctn	1,800 cartons (43,200 pcs)
200 L Industrial Drum	1 drum / pallet	80 drums (16,000 kg)

🏷️ OEM & Private Label: Custom brand logo & foil printing supported (MOQ 3,000 pcs).

⏱️ Lead Time: Standard stock dispatch in 5-7 days; custom OEM in 15-20 days.

🚢 Ports: FOB Shanghai Port or Ningbo Port, China.

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PU-40 polyurethane sealant export pallets loaded for international sea freight

Fumigated Export Pallets with Moisture-Shrink Film Protection