Sikafloor 21 PurCem - Heavy Duty Polyurethane Hybrid Flooring Screed
Sikafloor-21 PurCem is a multi-component, water-based coloured polyurethane hybrid screed with self-smoothing properties. It provides a smooth, matt, impervious, hard-wearing surface and is typically installed at a thickness of 3–6 mm. As a trusted Sika distributor, ProTrade Warehouse is pleased to offer this high-performance flooring solution to you with trade prices.
Uses
Sikafloor-21 PurCem is used as a scratch coat primer, basecoat, and wear coat layer in Sikafloor PurCem system build-ups. It is ideal for areas with medium to heavy loading, high chemical exposure, and abrasion. Benefit from our fast shipping Australia-wide and convenient pickup options.
Characteristics / Advantages
- Good chemical resistance
- High mechanical resistance
- High glass transition point
- Non-tainting / odourless
- VOC free
- Can be applied to substrates with high moisture content (7 days old or mature damp concrete - or 10% pbw)
Product Information
Composition: Water-based polyurethane cement hybrid
Packaging:
- Sikafloor PurCem 21: 20kg Kit (A+B+C+Pigment)
- Sikafloor PurCem 21: 80kg Mix: (A+B+C+Pigment) Made To Order: Non Stock item
Appearance and colour:
- Part A: coloured liquid after tinting
- Part A (neutral): light beige liquid
- Part B: brown liquid
- Part C: natural grey powder
- Pigment: colour pack - various colours
Standard RAL colours available include: Dusty Grey, Traffic Grey, Curtain Call, Beige Grass Green, Maize Yellow, Oxide Red, and Sky Blue.
Density: ~ 1.93 kg/l ± 0.03 (at +20 °C) for mixed Part A (pre-tinted)+B+C and Part A (neutral)+B+C+D.
Mixing Ratio: Mix full units only.
Consumption: ~ 1.93 kg/m²/mm
Layer Thickness: Scratch coat: 1–2 mm; Base- and wear coat: 3–6 mm
Ambient Air Temperature: +10 °C min. / +40 °C max.
Substrate Temperature: +10 °C min. / +40 °C max.
Substrate Moisture Content: Can be installed on substrates with higher moisture content. No ponding water. Check rising moisture. The substrate needs to be visibly dry and have adequate pull-off strength min 1.5 N/mm².
Pot Life (at various temperatures): ~ 35-40 mins (+10°C), ~ 22-25 mins (+20°C), ~ 15-18 mins (+30°C), ~ 12-15 mins (+35°C).
Waiting Time to Overcoating: Varies depending on substrate temperature (refer to datasheet for details).
Important Considerations
- Do not apply to PCC (polymer modified cement mortars) that may expand due to moisture when sealed with an impervious resin.
- Substrate outgassing: to minimize substrate outgassing Sikafloor-21 PurCem should be installed during declining temperatures. If outgassing persists, a scratch coat of Sikafloor-21 PurCem or Sikafloor PurCem 24 should be applied to completely seal the surface and reduce surface defects caused by rising temperatures or overly porous substrates. All concrete behaves differently; a trial application is recommended to determine if a scratch coat is required for broadcast systems. For smooth applications, a scratch coat is always advised.
- Always ensure good ventilation when using Sikafloor-21 PurCem in a confined space to prevent excessive ambient humidity.
- Freshly applied Sikafloor-21 PurCem must be protected from damp, condensation, and direct water contact (rain) for at least 24 hours.
- Protect the substrate during application from condensation from pipes or any overhead leaks.
- Do not apply to cracked or unsound substrates.
- Always allow a minimum of 48 hours after product application prior to placing into service in proximity with foodstuffs.
- Products of the Sikafloor PurCem product range are subject to discoloration when exposed to UV radiation. The extent depends on the colour. There are no measurable losses of any properties when this occurs, and it is a purely aesthetic matter.
- Products can be used outside provided the change in appearance is acceptable to the customer.
- In some slow curing conditions, soiling of the surface may occur when opened to foot traffic, even though mechanical properties have been achieved. It is advised to remove dirt using a dry mop or cloth. Avoid scrubbing with water for the first three days.
Application Instructions
Substrate Quality / Pre-treatment
The surface must be clean, dry, and free of all contaminants such as dirt, oil, grease, coatings, and surface treatments. All dust, loose, and friable material must be completely removed, preferably by vacuum. Pull-off strength should not be less than 1.5 N/mm². If in doubt, apply a test area first.
Mixing
Premix part A with a low-speed electric stirrer, then add part B and mix for 30 seconds. For the colour pack version, premix part A neutral with a low-speed electric stirrer and add part D to it until a uniform colour is achieved. Add part B and mix for 30 seconds.
Use a double paddle (axis) mixer and gradually add part C (aggregate) to the mixed resin. Allow part C to blend for a minimum of 2 minutes. If required, add Sikafloor PurCem Accelerator and mix for a further 1 minute to ensure complete mixing and a uniform moist mix. During mixing, scrape down the sides and bottom of the container with a flat or straight edge trowel at least once (parts A+B+C) to ensure thorough mixing.
Mixing Tools: Use a low-speed electric stirrer (300 - 400 rpm) for parts A and B. Use a double paddle mixer for the mortar mix.
Application
Broadcast Applications: For best results and long-term performance, Sikafloor 21 base coat should be applied with the addition of PurCem pigment. However, it can be installed without pigment if the client and applicator accept potential visible colour differences with deep scratches or surface damage. No noticeable difference in application is evident when used without pigment.
Smooth Applications: Scratch coat priming is required. Sikafloor 21 PurCem must be installed with the addition of Sikafloor PurCem Pigment for smooth applications.
Apply Sika floor 21 PurCem evenly at the prescribed thickness without any ridges when joining previous mixes by spreading the new mix and introducing it into the edges of the previous. Spike roll the product to release any air entrained by mixing and to assist in a final even out of the surface.
Time the application of the broadcast aggregate while the base can still receive it, generally between 2-5 minutes post-installation of the base, depending on ambient and substrate temperatures.
Take care to remove as much of the broadcast aggregate as possible before overcoating. Excess loose aggregate can result in uneven texture and colour shading in the finished floor.
Application of Sikafloor 31 or 33 PurCem finish coats must be carried out using the correct rolling equipment. Apply the product evenly and join wet edges promptly. Squeegee application followed by "laying off" with a roller is recommended for an even result. Cross "laying off" further assists this.
Cleaning of Equipment
Clean all tools and application equipment with Thinner C immediately after use. Hardened / cured material can only be mechanically removed.
ProTrade Warehouse offers Sikafloor 21 PurCem at trade prices with fast shipping Australia-wide . You can also choose to pick up from any Sika warehouse or our Silverwater store. As a leading Sika distributor, we ensure you get genuine products and excellent service.
