Infusion Epoxy Resin is a low-viscosity, two-component matrix system engineered to wet reinforcing fibres under vacuum infusion, RTM or RTM Light processing. Marjan Polymer Industries supplies application-matched infusion systems in Pakistan for structural composite parts, moulds and industrial development programmes.
What Makes an Epoxy Suitable for Infusion?
An infusion resin must remain sufficiently fluid for the complete fill distance while maintaining controlled reactivity, reliable air release and strong fibre wet-out. A general laminating or casting epoxy may gel too early, remain too viscous or develop properties that are not qualified for the intended laminate. Selection therefore begins with the mould, reinforcement, flow path, temperature and required service performance.
Available Engineering Routes
- General structural infusion: low-viscosity systems for glass- and carbon-fibre components.
- Long open-time infusion: hardener options for large parts, complex flow paths and warm workshops.
- High-temperature tooling: post-curable systems for precision moulds and prepreg tooling.
- Infusion and injection: grades compatible with RTM and RTM Light where documented.
- Biobased alternatives: available for projects with defined renewable-carbon or sustainability requirements.
Reference Grade Families
| Published reference system | Typical selection direction | Manufacturer-published indicators |
|---|---|---|
| Resoltech 1500 with 1502/1504 hardener | Structural parts and high-accuracy infusion tooling | Mixed viscosity about 250 mPa·s at 23°C; long gel time; post-curable Tg around 141°C, depending on approved cycle |
| Resoltech 1800 with 1803/1805/1807/1808 hardener | Structural parts, large marine structures, wind-energy components and tooling | Mixed viscosity about 190–325 mPa·s; gel-time range about 18 minutes to 7 hours; Tg up to about 120°C depending on hardener and cure |
| Other qualified systems | Room-temperature, high-Tg, clear, flame-retardant or biobased requirements | Specified from the selected manufacturer’s current technical data sheet |
These are comparison references, not interchangeable specifications. The quoted resin/hardener pair and its current data sheet control mix ratio, processing time, cure and final properties.
Parameters Confirmed Before Selection
- part dimensions, laminate thickness and longest resin-flow distance;
- carbon, glass, aramid or natural-fibre architecture and target fibre fraction;
- mould temperature, resin temperature and ambient workshop range;
- vacuum level, leak rate, feed and vent strategy and planned infusion time;
- required gel time, demould time, post-cure capability and production cycle;
- mechanical, thermal, chemical, fire/smoke or appearance requirements;
- applicable test standards, traceability and approval documentation.
Compatible Processes
- vacuum-assisted resin infusion (VARI/VARTM);
- resin transfer moulding and RTM Light where the grade is approved;
- large composite mould and tooling manufacture;
- selected vacuum-bag and closed-mould development routes.
Wet lay-up or filament winding suitability must be confirmed separately. Some very low-viscosity infusion hardeners are moisture-sensitive or designed only for a closed-mould process.
Recommended Process Workflow
- Engineer the flow: confirm reinforcement permeability, feed spacing, vent position and expected fill time using trials or process simulation.
- Prepare the mould: apply the qualified release system and place dry reinforcement, core, peel ply, distribution media and vacuum materials.
- Leak-test: stabilize full vacuum and verify the agreed leak-rate limit before mixing resin.
- Condition and meter: bring components to the approved temperature and measure the exact resin/hardener ratio.
- Mix and degas: mix thoroughly using low-air technique; degas where required by the grade and process plan.
- Infuse: manage feed and vent lines so the flow front remains controlled and air is not trapped.
- Cure and post-cure: maintain vacuum and follow the grade-specific room-temperature, elevated-temperature and cooling cycle.
- Inspect: record process data and verify laminate quality before release.
Quality-Control Plan
Recommended controls include batch and expiry verification, resin and hardener temperature, mix ratio, mixed viscosity or gel-time checks where applicable, vacuum-drop test, fill time, cure log, laminate thickness, fibre fraction, void content, surface inspection and mechanical coupons. High-temperature tooling requires an approved post-cure and dimensional verification.
Typical Applications
- wind-energy and renewable-energy composite structures;
- marine panels, hull components and large mouldings;
- automotive, rail and transport composite parts;
- industrial enclosures, covers and structural panels;
- high-accuracy moulds and tooling for composite production;
- university and industrial composite research in Pakistan.
Storage and Safety
Store resin and hardener sealed under the conditions stated in the current technical and safety data sheets. Control humidity, contamination and component temperature. Wear suitable gloves, eye protection and protective clothing, and provide the required ventilation. Mixed epoxy can generate significant exotherm; never leave an excessive mixed mass in a deep container.
Information Required for a Quotation
Share part dimensions, reinforcement and core, laminate weight or thickness, mould and ambient temperature, target infusion time, vacuum equipment, required cure and post-cure, service temperature, mechanical or certification targets, trial or production quantity and delivery city in Pakistan. MPI will then confirm the appropriate grade family, hardener, pack size and lead time.
Frequently Asked Questions
Is infusion epoxy the same as laminating epoxy?
No. Infusion resin is selected for low viscosity, stable flow and controlled gel time through a dry reinforcement stack. A laminating grade is not automatically suitable for closed-mould infusion.
What viscosity should an infusion resin have?
There is no single universal value. The acceptable viscosity depends on fibre permeability, flow distance, temperature and fill time. Many structural infusion systems are in the low-hundreds of mPa·s at their stated test temperature.
What mixing ratio should be used?
Use only the ratio published for the exact resin and hardener combination. Ratios such as 100:30 cannot be applied generically to every infusion system.
Can I select a faster or slower hardener?
Many systems offer multiple hardeners. Selection must still provide enough time for mixing, degassing and complete mould fill before gel.
Can infusion epoxy cure at room temperature?
Some grades develop handling strength at ambient temperature, but structural or high-temperature properties may require a defined elevated-temperature post-cure.
Is the resin suitable for carbon fibre?
Qualified infusion systems can process carbon, glass and selected aramid reinforcements. The grade must be matched to fibre architecture, permeability and the required laminate properties.
Can MPI support large-part infusion in Pakistan?
Yes. MPI can review resin selection alongside vacuum equipment, feed strategy, consumables, temperature control and trial planning for large parts.
Does low viscosity guarantee a void-free laminate?
No. Voids also depend on leak control, reinforcement preparation, flow-front management, temperature, degassing and cure discipline.
Are high-temperature infusion systems available?
Yes. Post-curable structural and tooling grades are available, but required Tg and cure equipment must be confirmed before selection.
What is needed for a price and lead-time quotation?
Provide part size, reinforcement, process temperature, required gel time, performance targets, quantity and delivery location in Pakistan.
