Two-Component Polyurethane Sealant

Standard: JC/T 482-2022 ｜ Grades: N20LM and N25LM (low modulus); N20HM and N25HM (high modulus)

Key points

Standard: JC/T 482-2022; graded and tested by an accredited third-party laboratory.
Grades: N20LM and N25LM (low modulus); N20HM and N25HM (high modulus).
Price: RMB 4.5–12 per kg, depending on modulus, movement capability and tensile performance. MOQ: 1 drum minimum; orders up to 10 t ship in 1 day.
Inspection commitment: pre-purchase sampling, third-party re-testing, full refund if a test fails.

Overview

Two-component polyurethane sealant is a paste supplied in parts A and B, cured at room temperature into an elastic seal. It serves municipal bridges, utility tunnels, underground garages, roofs, concrete expansion and settlement joints, airport runways and sewage basins, sealing joints subject to thermal movement and foundation settlement.

Technical data

Measured values from the third-party test report for N20LM two-component polyurethane sealant, assessed to JC/T 482-2022.
Property	Measured	Requirement
Appearance	Smooth uniform paste, free of bubbles and skinning	Conforms
Density	1.52 g/cm³	Nominal ±0.1 g/cm³
Flow / sag	0 mm	≤3 mm
Skin formation time	5 h	≤24 h
Tooling life	3 h	≥0.5 h
Elastic recovery at 100% extension	85 %	≥70 %
Adhesion at 100% extension	No failure	No failure
Adhesion at constant extension after immersion	No failure	No failure
Adhesion after cold draw / hot press	No failure	No failure
Mass loss	1.90 %	≤5 %
Tensile modulus at 23 °C	0.35 MPa	≤0.4 MPa
Tensile modulus at -20 °C	0.51 MPa	≤0.6 MPa

Advantages

Excellent adhesion to concrete, stone and metal substrates.
High elasticity and strong movement accommodation; tear- and ageing-resistant, non-sag after cure and low shrinkage.
Good weather resistance — no yellowing outdoors — and no cracking at -40 °C, which suits roofs and other exposed locations.
Passed GB/T 17219 hygiene assessment for drinking-water contact materials.
Pre-purchase sampling, third-party re-testing, full refund if a test fails.

Applications

Bridge expansion joints (deck underside, box girder joints)
Metro lining joints and tunnel secondary lining settlement joints
Utility tunnel expansion joints
Roof expansion and division joints
Airport runways, underground garages and sewage basins

Installation

Prepare the substrate: dry or damp is acceptable, but standing water must be drained first.
Place foam backer rod and masking tape, inject with a caulking gun, then tool and press the bead against the joint faces.
Mix components A and B mechanically for 2–5 minutes until the colour is uniform with no pale streaks.
Match the grade to the joint: low modulus for movement joints, high modulus for rigid joints.
Use the mixed sealant within its tooling life (3 hours measured on our test batch); protect from rain during early cure.

FAQ

What ratio should A and B be mixed at, and what goes wrong if mixing is incomplete?

The usual ratio is A:B = 10:1 by weight, with error kept within ±1–5%; follow the datasheet. Mix mechanically for 2–5 minutes until uniform with no pale streaks. Too little B leaves the sealant soft and uncured; too much makes it brittle, inelastic and prone to cracking.

How long before the surface can take traffic?

At 25 °C skin formation takes about 1–4 hours (5 hours measured on our test batch); after 24 hours it can be touched lightly. Full cure takes about 7 days to reach tensile strength and waterproofing performance, after which it can take traffic, be backfilled and be hydrostatically tested. At around 5 °C in winter the cycle extends to 10–14 days.

Low modulus or high modulus?

Low modulus (N20LM, N25LM) for joints with large or frequent movement — the bead is softer and follows displacement better. High modulus (N20HM, N25HM) for rigid joints and load-bearing locations requiring higher strength and compression resistance.

How does it compare with polysulfide sealant?

By duty: polysulfide for permanent immersion (reservoirs, basins, dams); polyurethane for pavement saw cuts, car parks and industrial floors where abrasion, tear resistance and large movement matter. Neither suits continuous service above 80 °C or strong acid and alkali.

Price and delivery

Reference price	RMB 4.5–12 per kg, depending on modulus, movement capability and tensile performance
MOQ and lead time	1 drum minimum; orders up to 10 t ship in 1 day
Packaging	Palletised drums, woven bags or cartons; LCL and FCL shipping available.

Contact

Company: Hebei Hualing Rubber Co., Ltd.
Address: No.97, Xifantun Village, Wuqiang Town, Wuqiang County, Hengshui City, Hebei Province, China
Contact: Mr. Hou (Sales Manager)
Tel: +86 13081809758
Email: mifengjiaochang@163.com