Sikafloor®-21 PurCem®
Self-smoothing high strength, chemical and thermal shock resistant polyurethene hybrid flooring screed with a slip resistant finish
Sikafloor®-21 PurCem® is a self-smoothing multi-component, waterbased colored polyurethane hybrid flooring screed. It has flat, high abrasion, chemical, impact and slip-resistant finish.
- Good resistance to specific chemicals
- High mechanical resistance
- Low VOC emissions
- Odourless
- Non-tainting
- Thermal expansion properties similar to concrete
- Tolerant to substrates with high moisture content
Usage
The Product is used as a scratch coat or wearing coat layer in Sikafloor® PurCem® flooring systems. Please note:- The Product may only be used by experienced professionals.
Advantages
- Good resistance to specific chemicals
- High mechanical resistance
- Low VOC emissions
- Odourless
- Non-tainting
- Thermal expansion properties similar to concrete
- Tolerant to substrates with high moisture content
Packaging
Container Part A neutral | 2.5 kg |
Container Part A | 3 kg |
Container Part B | 3 kg |
Part C | 15 kg bag |
Part D | 0.5 kg plastic pouch for substrate A neutral |
Packaging combined | 21 kg ready to mix units |
Refer to the current price list for available packaging variations.
Colour
Part A neutral | Light biege liquid |
Part A | Coloured liquid |
Part B | Brown liquid |
Part C | Natural grey powder |
Part D | colourpack as per list below for part A neutral |
Cured appearance | Matt finish |
Cured colour | Pebble Grey, Beige, Golden Yellow, Dusty Grey, Carmine Red, Agate Grey, Marine Blue, Yellow Green |
Note: When the Product is exposed to direct sunlight, there may be some discolouration and colour variation. This has no influence on the function and performance of the Product.
For colour matching: Apply colour sample and confirm selected colour under real lighting conditions.
Product Details
SUSTAINABILITY
- Environmental Product Declaration (EPD) in accordance with EN 15804. EPD independently verified by Institut für Bauen und Umwelt e.V. (IBU)
- VOC emissions AgBB, Sikafloor®-21 PurCem®, Approval No. 392-2014-00087001D
- VOC emissions AgBB, Sikafloor®-21 PurCem®, eurofins, Certificate No. G10004
- VOC emission classification of building materials RTS M1
- Conforms with LEED v4 EQ credit: Low-emitting materials
- Conforms with LEED v4 MR credit: Building product disclosure and optimization — Environmental Product Declarations (option 1)
CERTIFICATES AND TEST REPORTS
- CE marking and declaration of performance based on EN 13813:2002 Screed material and floor screeds — Screed material — Properties and requirements — Synthetic resin screed material
- Cleaning test Sikafloor®-21 PurCem, CSM Fraunhofer, Certificate No. 1403-695
- Cleanability test Sikafloor®-21 PurCem®, Fraunhofer, Report No. SI 1208-611
- Impact resistance test Sikafloor®-21 PurCem®, PRA, Report No. 75221-151
- Tainting test ISO 4120, Sikafloor®-21 PurCem®, Campden, Report No. 125424/1a
- Abrasion resistance test Sikafloor®-20 PurCem®/-21 PurCem®, Face consultants, Report No. FC/12/3850
- Fire testing EN 13501-1, APPLUS, No.21/32302953-2
Composition
Water-based polyurethane cement hybrid
Shelf life
Part A | 12 months from date of production |
Part B | 12 months from date of production |
Part C | 9 months from date of production |
Part D | 12 months from date of production |
Always refer to the best before date of the individual packaging.
Storage conditions
The Product must be stored in original, unopened and undamaged sealed packaging in dry conditions at temperatures between +5 °C and +30 °C. Always refer to packaging.
Refer to the current Safety Data Sheet for information on safe handling and storage.
Density
Mixed Product | ~1.93 kg/l at +20 °C |
Shore D Hardness
Cured 7 days at +23 °C | 85 |
Compressive strength
Cured 28 days at +23 °C | 50 N/mm² |
Flexural-strength
Cured 28 days at +23 °C | ~10 N/mm² |
Tensile adhesion strength
≥ 2.5 (2.0) N/mm² | (EN 1542) |
Reaction to fire
Class Bfl-s1 | (EN 13501-1) |
Application
Mixing ratio
Part A : Part B : Part C : Part D | 2.5 : 3.0 : 15 : 0.5 |
Part A : Part B : Part C | 3.0 : 3.0 : 15 |
Layer thickness
Scratch coat | 1–2 mm |
Wear or base coat | 3–6 mm |
Material temperature
Minimum | +10 °C |
Maximum | +35 °C |
Ambient air temperature
Minimum | +10 °C |
Maximum | +35 °C |
Relative air humidity
Maximum | 80 % |
Dew point
Beware of condensation. The substrate and uncured applied product must be at least +3 °C above dew point to reduce the risk of condensation or blooming on the surface of the applied product. Low temperatures and high humidity conditions increase the probability of blooming.
Substrate temperature
Minimum | +10 °C |
Maximum | +35 °C |
Substrate moisture content
The Product can be installed on substrates with a higher moisture content. No ponding water may be present on the surface. Check for rising moisture. The substrate must be visibly dry and must have a minimum pull-off strength of 1.5 N/mm².
Pot Life
+10 °C | ~40 minutes |
+20 °C | ~25 minutes |
+30 °C | ~18 minutes |
+35 °C | ~15 minutes |
Waiting time to overcoating
Before overcoating the Product allow:
Substrate temperature | Minimum | Maximum |
+10 °C | 24 hours | 72 hours |
+20 °C | 24 hours | 48 hours |
+30 °C | 12 hours | 24 hours |
+35 °C | 12 hours | 24 hours |
Note: Times are approximate and will be affected by changing ambient conditions, particularly temperature and relative humidity.
Note: If a primer other than a scratch coat of Sikafloor PurCem is applied, refer to the relevant PDS of the chosen product for curing times. Ensure that the primer or scratch coat is fully cured before the application of subsequent Sikafloor PurCem layers.
Consumption
~1.9 kg/m² per mm thickness
EQUIPMENT
MIXING EQUIPMENT
Electric single paddle mixer (300 to 400 rpm)
Electric double paddle mixer (>700 W, 300 to 400 rpm)
Forced action / rotating pan / double paddle or trough type mixer (300–400 rpm )
APPLICATION EQUIPMENT
Flat, round edge steel trowel
Spiked roller
Trowels, including serrated
Pin leveller
SUBSTRATE QUALITY
TREATMENT OF JOINTS AND CRACKS
IMPORTANT
Incorrect treatment of cracks
The incorrect assessment and treatment of cracks may lead to a reduced service life and reflective cracking.
Construction joints and existing static surface cracks in substrate require pre-treating before full layer application. Use Sikadur® or Sikafloor® resins.
The System can be applied on green or damp concrete with no standing water. Allow for at least 3 days for early concrete shrinkage to occur to prevent shrinkage cracks from appearing on the wearing surface.
Cementitious substrates (concrete / screed) must be structurally sound and of sufficient compressive strength (minimum 25 N/mm2) with a minimum tensile strength of 1.5 N/mm2.
Substrates must be clean, dry and free of all contaminants such as dirt, oil, grease, coatings, laitance, surface treatments and loose friable material.
SUBSTRATE PREPARATION
To prevent curling of the applied product during curing, place retaining grooves in the substrate along all exposed edges (perimeter, joints, connections, plinths, columns, covings and drains / gullies) as shown in the application details of the Sika Method Statement: Sikafloor®- PurCem®. Width and depth must be twice the thickness of the floor finish.
MIXING
IMPORTANT
Mix full units only
3 PART MIXING PROCEDURE
- Mix Part A (resin) until the coloured pigment is dispersed and a uniform colour is achieved.
- Add Part B (hardener) to Part A.
- Mix Part A + B continuously for 30 seconds until a uniformly coloured mix is achieved.
- After mixing for 30 seconds, gradually add Part C while you continue mixing.
- After combining all parts, mix for an additional 2 minutes, until a uniform mix is achieved. Note: At ambient temperatures less than +15 °C mix between 30 seconds and 1 minute longer.
- To ensure thorough mixing, pour materials into another container and mix again to achieve a smooth and uniform mix.
- During the final mixing stage, scrape down the sides and bottom of the mixing container with a flat or straight edge trowel at least once to ensure complete mixing.
4 PART MIXING PROCEDURE
- Mix Part A (resin) for ~30 seconds.
- Add Part D (colour pack) to Part A.
- Mix Part A + D continuously for 30 seconds until a uniformly coloured mix is achieved.
- After mixing for 30 seconds, gradually add Part B and continue mixing for 30 seconds.
- After mixing for 30 seconds, gradually add Part C while you continue mixing.
- After combining all parts, mix for an additional 2 minutes, until a uniform mix is achieved. Note: At ambient temperatures less than +15 °C mix between 30 seconds and 1 minute longer.
- To ensure thorough mixing, pour materials into another container and mix again to achieve a smooth and uniform mix.
- During the final mixing stage, scrape down the sides and bottom of the mixing container with a flat or straight edge trowel at least once to ensure complete mixing.
APPLICATION
IMPORTANT
Protecting the material after application
After application, protect the System from damp, condensation and direct water contact for at least 24 hours.
IMPORTANT
Protect from overhead leaks and condensation
Protect the Product during application from pipe condensation or any overhead leaks.
IMPORTANT
Ventilation in confined spaces
Always ensure good ventilation when applying the Product in a confined space.
IMPORTANT
Application on polymer modified cement mortars
Do not apply the product on polymer modified cement mortars if the mortar expands when sealed with an impervious resin.
IMPORTANT
Waiting time for foodstuff
Allow a minimum of 48 hours after application before placing foodstuff in the same area.
SCRATCH COAT
- Pour the mixed Product onto the prepared substrate.
- Scrape the Product into the prepared surface with a steel trowel to the required thickness so that the surface texture is filled.
WEARING LAYER
- Pour the mixed Product onto the substrate. Note: The consumption is specified in Application Information.
- Apply the Product evenly over the surface with a pin leveller or a trowel.
- Back roll the surface in two directions at right angles with a spike roller. Note: Maintain a "wet edge" during application to achieve a seamless finish.
CLEANING OF EQUIPMENT
Clean all tools and application equipment with Sika® Thinner C immediately after use. Hardened material can only be removed mechanically.