Polyurea Classroom

Typical hot-spray polyurea uses two components, metered, heated and mixed by dedicated equipment to rapidly form a continuous elastic coating. Applications include building waterproofing, industrial floors, tanks and wastewater facilities. Selection must account for the substrate, loads and exposure media.

Practical tipFast film formation supports continuous application, but not every grade is suitable for prolonged immersion or every chemical. For corrosion protection, specify the chemical, concentration and operating temperature first.

Single-component hand-applied polyurea avoids on-site two-component proportioning and can suit detailing and local repairs. For large continuous areas or demanding schedules, consider a hot-spray system where suitable equipment is available.

Practical tipConsider the substrate, service environment, area and schedule together. Curing mechanisms and application conditions vary between single-component formulations. Confirm the requirements for the selected grade before planning the work.

Kangyuan lists KY-204 and KY-205 as single-component hand-applied polyurea. KY-204 focuses on ease of application, while KY-205 offers resistance to yellowing. Where exposed surfaces need colour retention, discuss KY-205 and a compatible finishing system.

Practical tipA product feature alone is not a complete specification. State whether the area is indoors or outdoors, the substrate, colour, immersion and abrasion requirements. Request the grade-specific instructions for thickness, consumption and curing.

Remove laitance, dust, oil, release agents and loose material from concrete, and repair voids and defects. Degrease and derust metal to the surface condition required by the coating system. Sound, clean substrates provide the basis for adhesion.

Practical tipCheck the soundness and compatibility of existing coatings before retaining them. After preparation, inspect and clean the surface, then proceed promptly to avoid contamination.

A primer provides an interface between the substrate and coating and can help seal pores. Choose a compatible primer for the substrate. Increasing coating thickness does not compensate for weak or inadequately prepared surfaces.

Practical tipTreat cracks, pipe penetrations, corners and movement joints according to the detailing design. Movement joints must retain their ability to move; simply coating across them is not a complete solution.

Check substrate moisture, air humidity, substrate temperature and dew point. Condensation can affect adhesion. A material's ability to cure under certain conditions does not mean it can be applied over standing water or condensation.

Practical tipPermitted conditions vary by grade. Check the product instructions and forecast, allowing a suitable window for application and initial curing. Reschedule if condensation, rain or temperature and humidity outside the permitted range are expected.

Check metering, component ratio, material temperature and supply against the product instructions. Carry out a trial spray to assess mixing and film formation. Hot spraying requires experienced operators; do not copy settings from another brand or grade.

Practical tipProceed to the main area only after a satisfactory trial. Monitor film condition and coverage throughout application, stopping to investigate abnormalities. Follow the safety data sheet and site requirements for protection and ventilation.

Before opening, check the grade, batch and storage condition. Follow the instructions for stirring and tool selection. Do not add water, solvent or other materials to adjust viscosity without authorisation. Control consumption, thickness per coat and recoating intervals.

Practical tipSingle-component materials cannot necessarily cure properly at any applied thickness. Confirm maximum coat thickness, recoating conditions, usable life after opening and storage of remaining material. If the recoating window is exceeded, confirm the required surface treatment.

First investigate substrate pores, moisture, contamination and intercoat adhesion to establish the repair scope. Repeatedly coating over loose, damp or blistered areas may allow the defect to recur.

Practical tipInspect representative areas, remove unsound material and restore the primer and coating as required by the repair system. Check continuity and the connection to the existing coating afterwards, recording inspections at key stages.

Touch-dry, ready to recoat and ready for service are different stages. Rapid gel formation does not mean a sprayed coating has immediately reached its final properties. Single-component systems also require the specified curing period.

Practical tipBefore service, check appearance, continuity, thickness and adhesion as specified. Confirm separate times for foot traffic, loading, water filling and chemical exposure with the manufacturer, taking actual temperature and humidity into account.