XMC® 7119 Two-Component Graphene Foaming Adhesive: Let the Package Meter the Ratio, Let the Chemistry Set the Clock

In building services installations, every cable penetration through a wall or slab, every pipe sleeve and every gap between wall and curtain wall ends up with a seal. It is rarely visible, yet it is exactly what gets examined at fire inspection, during maintenance rounds and after an incident.

Choosing the sealant has long been a trade-off.

One-component foam is easy to apply, but it expands a great deal and the expansion is hard to control; thick sections cure from ambient moisture and may take a day to set through. Whether it resists flame depends on how much flame retardant the formulation carries, and adding enough usually means giving up something else. Two-component products start from a better position on flame resistance and strength, but once the ratio is handed to on-site hand weighing, a new variable enters — a few percentage points off and cure speed, expansion and final strength all shift with it.

1. Two components, 1:1, one mixing nozzle: fewer variables, steadier results

XMC® 7119 is a reactive polyurethane foaming material supplied as two components in a fixed 1:1 pack: Component A is a polyether polyol and Component B is MDI, each in a 200 ml cartridge. On site, the original plugs are replaced with a dedicated two-component mixing nozzle and the cartridges are used with a two-component gun. A and B meet inside the nozzle and the mixed material is injected straight into the gap or cavity — no weighing, no stirring, and no open-mixing pot life to manage.

The 1:1 ratio is not just convenient arithmetic. Two-component polyurethane cures by chemical reaction, and the A/B ratio governs crosslink density: too much A leaves the foam under-cured and soft, with poor strength; too much B makes the reaction run hot, producing a brittle foam that cracks easily. Packaging in a fixed 1:1 ratio reduces metering error to the accuracy of the filling line, leaving temperature and operator pace as the only remaining variables on site.

2. 20–30 seconds of working time, 8–10 minutes to set

The TDS gives the timing: at 25°C, working time is 20–30 seconds, foaming time is 20–30 seconds, and full cure takes 8–10 minutes, affected by temperature.

Those numbers translate directly into a site rhythm. After dispensing, the material must be delivered into the hole or cavity within 20–30 seconds. Past that window the foam has begun to rise and thicken, and forcing it in afterwards leaves voids and cold joints. Once it is in place, however, the next trade can move in after 8–10 minutes — backfilling, rendering and cover plates follow the seal without a waiting day in between.

Against the day-long full cure typical of one-component moisture-curing foams, that difference is directly calculable in electrical and fire-stopping sequences under schedule pressure.

3. 8–12 times expansion, closed-cell structure

Expansion ratio is 8–12 times by volume, and cured density is 50–70 kg/m³. Compared with the 40-times-plus expansion of a one-component gun foam, 7119 expands far more moderately.

For sealing work that is a benefit, not a compromise. A penetration needs to be filled, dense and crack-free — not maximally expanded. Over-expansion pushes sleeves off line, cracks lightweight blockwork and loosens cable bundles already installed, and the rework costs far more than the material.

The cured foam is closed-cell. The TDS describes it as combining adhesion, sealing, sound insulation and thermal insulation — a closed-cell structure limits moisture transfer between cells, which is why the same product serves both waterproof sealing and insulation filling.

4. Flame resistance: two mechanisms in one formulation

The MSDS composition table sets out the skeleton of the formulation: MDI 50%, polyether polyol 10–30%, expanded graphite 5–10%, TCPP (tris(2-chloroisopropyl) phosphate) 5–10%, dibutyltin dilaurate 0.2–0.5%, water 1–2% and chlorinated paraffin 2–5%.

That is a combined condensed-phase and gas-phase approach: the graphitic carbon material promotes char formation under heat and builds an insulating, oxygen-starving char layer, while the phosphorus- and halogen-bearing components scavenge free radicals in the gas phase and interrupt the combustion chain. The MSDS characterises the product as extremely difficult to burn and self-extinguishing when removed from the flame, with an ignition temperature of at least 800°C.

The MSDS field for main use is more specific still: fire-retardant sealing for cable and wire penetrations. That explains the product's positioning — it is not a general-purpose gap filler, but a seal built for penetrations that have to pass a fire inspection.

Note: the TDS does not state a flame-retardant rating or a fire-resistance period, and no such claim is made here. Where a project requires a classification, the corresponding test report should be referenced.

5. It has to hold before it can seal

A seal usually fails by detaching or cracking before it fails by burning through. XMC® 7119 reaches ≥2.5 MPa adhesion to metal (TDS data) and serves from -40°C to +120°C after curing, covering the conditions typical of riser shafts, roofs and equipment cavities. A low-density closed-cell foam with that level of adhesion can carry vibration and structural movement on its own rather than relying on external support to stay in place.

6. Beyond construction: four applications already in use

Applications listed in the TDS:

• Construction: gap filling, pipe sealing, wall insulation and sealing of cable trenches;
• Automotive manufacturing: cavity filling, sound insulation and vibration damping, lightweight structures;
• Electronics and electrical appliances: component fixing and waterproof sealing;
• Industrial maintenance: rapid repair and mould filling.

Automotive cavities and electronic potting are precisely where a fast-curing two-component foam fits: short takt times, one-shot forming, and no tolerance for long curing waits. The same logic of a 1:1 pack and a mixing nozzle works on a production line and on a building site alike.

7. Typical physical properties

8. Packaging, storage and transport

9. Application notes

1. Surface preparation: the substrate must be clean, free of oil, grease and dust. On porous or dusty substrates, run a small trial patch first to confirm adhesion.
2. Nozzle: remove the original plugs and fit the dedicated two-component mixing nozzle; use with a two-component gun.
3. Dispensing and injection: A and B are mixed in the nozzle and injected directly into the gap or cavity, and injection must be completed within the 20–30 second working time.
4. Curing: allow to cure naturally at 25°C; higher temperature and humidity accelerate the reaction.
5. Key restriction: the mixed material must be kept away from moisture, which causes premature curing — this is stated explicitly in the TDS precautions.
6. Environment: recommended application temperature 10–35°C, relative humidity ≤80%.
7. Before large-scale work, run a small trial batch to confirm material compatibility and actual consumption.

About XMC

Shanghai XMC New Material Technology Co., Ltd. was founded in 2004 and specializes in the research, development and manufacturing of sealants and adhesive products for construction and industrial applications. With more than two decades of industry experience, XMC has built a modern production system integrating product development, manufacturing and international trade, with a plant area of approximately 80,000 m², annual output of approximately 60,000 t, and more than 500 containers shipped per year.

XMC's product portfolio covers silicone sealants, hybrid sealants, MS sealants, liquid nails, polyurethane foam, automotive sealants and various industrial bonding materials. The company serves global distributors, building material suppliers and project customers with stable products and customized services, backed by 20 years of OEM/ODM experience and more than 1,000 custom colours.

For more information about XMC products and cooperation opportunities, please visit: https://www.xmcsil.com