Sikafloor® -21N PurCem (CN) Medium Duty Self-Levelling Polyurethane Screed
发布时间：2023/05/15
Product Data Sheet
Edition 20/03/2012EN
Sikafloor® -21N PurCem (CN)
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Sikafloor® -21N PurCem (CN)
Sikafloor® -21N PurCem (CN)
Medium Duty Self-Levelling Polyurethane Screed
Product
Description
Sikafloor® -21N PurCem (CN) are self-levelling, medium to heavy duty, solid colour,
four-component, water dispersed polyurethane-based / cement and aggregate
screeds designed to provide excellent resistance to abrasion, impact, chemical
attack and other physical aggression. Sikafloor ® 21NPurcem (CN) has an
aesthetic, easy to clean, smooth aggregate texture. The systems are typically
installed at 4.5 to 6 mm thickness.
Uses
Sikafloor® -21N PurCem (CN) floors are primarily used to protect concrete
substrates, but are equally effective over most steel surfaces that have been
properly prepared and supported.
Typically used in food processing plants, wet & dry process areas, freezers &
coolers, dairies, breweries, wineries, distilleries, laboratories, chemical process
plants, pulp and paper plants, warehouses and storage areas.
Characteristics /
Advantages
Resists a very wide range of organic and inorganic acids, alkalis, amines, salts
and solvents. Consult Sika Technical Sales for full details. Refer to the Sikafloor®
PurCem Chemical Resistance Chart.
Similar coefficient of thermal expansion to concrete allowing movement with the
substrate through normal thermal cycling. It will perform and retain its physical
characteristics through a wide temperature range from -40ºC up to 120ºC.
Bond strength in excess of the tensile strength of concrete, concrete will fail first.
Non-taint, odourless.
Behaves plastically under impact / deforms but will not crack or debond.
High abrasion qualities result from its pure silica aggregate structure.
Extra Expansion joints are not necessary; simply maintain and extend existing
expansion joints up through the Sikafloor® PurCem (CN) Flooring System.
Easily maintained.
USDA acceptance for use in food plants in the U.S.A.
Canadian Food Inspection Agency acceptance for use in food plants in Canada.
British Standard Specifications (BSS) acceptance for use in the U.K.
Technical Data
Packaging
33.4 kg/set
Comp.A: 5 kg/pail, Comp.B: 5.0 kg/pail, Comp.C: 21.8kg/bag, Comp.D: 1.6 kg/pack
Colour
Seven standard colours are available (all are approximate):
Beige, Maize Yellow, Oxide Red, Grass Green, Slate Grey, Dusty Grey, Traffic
Grey
Custom colors subject to minimum orders.
Yield
Approximately 3.8 m2 per set unit at 4.5 mm
Approximately 2.8 m2 per unit at 6 mm
(These figures do not allow for surface porosity, profile or wastage)
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Sikafloor® -21N PurCem (CN)
Shelf Life
Components A and B: 1 year in original unopened packaging.
Components C and D: 6 months in original unopened packaging.
Store dry between 10 ºC - 25 ºC. Protect from freezing.
Mix Ratio
Components A:B:C:D = Mix full units only.
Properties at 23°C and
50% R.H.
Application Temperature
10ºC min. / 30ºC max.
Optimal application temperatures range : 20ºC - 25ºC
Density ASTM C 905
1.93 kg/L
Flow
300 mm
Service Temperature
-40ºC min. / 120ºC max.
Cure Time at
Usable pot life 20-25 min at 20ºC
Initial join up time 25-30 min at 20ºC / 6 mm
Cure to foot traffic 10-12 h at 20ºC / 6 mm
Cure to light traffic 14-16 h at 20ºC / 6 mm
Full cure 5 days at 20ºC / 6 mm
Softening Point
130 ºC
Compressive Strength
ASTM C579
24 h 22 MPa
7 days 37 MPa
28 days 40 MPa
Tensile Strength
ASTM C 307
6.5 MPa
Flexural Strength
ASTM C 580
14.7 MPa
Bond Strength
ASTM D 4541
> 1.75 MPa (substrate failure)
Thermal Compatibility
ASTM C 884
Pass
Hardness, Shore D
ASTM D 2240
80-85
Indentation
MIL-PRF-24613
~ 0%
Impact Resistance
ASTM D 2794
6.81 joules at 3 mm of thickness
Abrasion Resistance
ASTM D 4060
H-22/1000 cycles/1000 g
-2.26 g
Coefficient of Friction
ASTM D 1894-61T
Steel 0.3
Rubber 0.5
Coefficient of Thermal
Expansion ASTM D 696
1.6 x 10-5 mm/mm/ºC
Water Absorption ASTM
C 413
0.10%
Chemical Resistance
Consult Sika Technical Sales
How to Use
Surface Preparation
Concrete surfaces must be clean and sound. Remove all dust, dirt, existing paint
films, efflorescence, exudates, laitance, form oils, hydraulic or fuel oils, brake fluid, 3
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Sikafloor® -21N PurCem (CN)
grease, fungus, mildew, biological residues or any other contaminants which may
prohibit good bond. Prepare the surface by appropriate mechanical means,
approved by Sika to achieve (CSP 3-6). The compressive strength of the concrete
substrate should be at least 25 MPa at 28 days and a minimum of 1.5 MPa in
tension at the time of application. Repairs to cementitious substrates, filling of
blowholes, leveling of irregularities, etc. should be carried out using an appropriate
Sika profiling mortar.
Contact Sika Technical Sales for a recommendation.
Edge Terminations - All free edges of a Sikafloor® PurCem (CN), whether at the
perimeter, along gutters or at drains require extra anchorage to distribute
mechanical and thermal stresses. This is best achieved by forming or cutting
grooves in the concrete. Grooves should have a depth and width of 2 times
thickness of the Sikafloor® PurCem (CN) mortar. Refer to the edge details provided.
If necessary, protect all free edges with mechanically attached metal strips.
Never featheredge, always turn into an anchor groove.
Expansion Joints - Should be provided in the substrates at the intersection of
dissimilar materials. Isolate areas subject to thermal stresses, vibration movements
or around load-bearing columns and at vessel sealing rings. Refer to details.
Mixing
Mixing will be affected by temperature.
Condition materials for use from 18ºC to 25ºC.
Stir Component A first for approx. 15 seconds.
Add component B, and mix for approx. 30 seconds with low speed mixer.
While mixing, add simultaneously but slowly (DON’T DUMP!) component C
(powder) and Component D (pigment pack) within 15 seconds.
Further mix for 2 minutes until the mixture is homogeneous and the pigment is
uniformly dispersed.
Mix full unit only
Note: Improve flowability on cool substrates can be achieved by removing a
maximum of 1 kg of Component C (powder) per unit.
Application Sikafloor® -21N PurCem (CN)
Scratch Coat - Priming of concrete substrates is not usually required under typical
circumstances. However, due to variations in concrete quality, surface conditions,
surface preparation and ambient conditions, reference test areas are recommended
to determine whether priming is required to prevent the possibility of blisters,
debonding, pinholes and other aesthetic variations. Mix and apply a scratch coat of
Sikafloor® -21N PurCem (CN) using steel trowels to spread the materials to
approximately 1.5 mm thickness, approximately 11 m2 per unit. This application
must seal the concrete surface, fill in surface irregularities including pock marks,
non-moving control joints and cracks. Allow overnight cure (16 hours) at 20ºC
before application of the body coat.
Body Coat - Mix and pour the Sikafloor®-21N PurCem (CN) materials on the floor.
Spread to the desired thickness using a notched squeegee, trowel or screed bar.
Take care to spread newly mixed materials across the transition of previous applied
mixes before the surface begins to set. Immediately spike roll the surface to release
trapped air in the matrix. Allow a minimum 14 hour cure period at 20ºC before light
traffic.
Clean Up
Clean all tools and equipment with Sika® Equipment Cleaner/Epoxy Thinner. Wash
soiled hands and skin thoroughly in hot soapy water or use Sika® Hand Cleaner.
Once hardened, product can only be removed mechanically.
Maintenance
Sikafloor® PurCem (CN) floors are easily cleaned using a stiff brushing action and
or high-pressure water, preferably hot, and even live steam. Degreasing agents and
detergents will assist, but do not use any compounds containing Phenol as the floor
colour may be damaged. Consult the cleaning compound manufacturer’s printing
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Sikafloor® -21N PurCem (CN)
Limitations
■ Do not apply below 10ºC or above 30ºC / maximum relative humidity 85%.
■ Do not apply to un-reinforced sand cement screeds, asphaltic or bitumen
substrate, glazed tile or non-porous brick, tile and magnesite, copper, aluminium,
soft wood, or urethane composition, elastomeric membranes, fibre reinforced
polyester (FRP) composites.
■ Do not apply to wet or green concrete or polymer modified patches if the
moisture content > 10%.
■ Do not apply to concrete if air or substrate temperature is within 3ºC of dew
point.
■ Protect substrate during application from condensation from pipes or any
overhead leaks.
■ Do not apply to vertical or overhead surfaces / for vertical surfaces refer to
Sikafloor® 29N PurCem (CN)
■ Do not featheredge.
■ Do not mix Sikafloor® PurCem materials by hand / mechanical mix only.
■ Do not apply to cracked or unsound substrates.
■ Do not apply to surfaces where moisture vapour can condense and freeze.
■ Steam cleaning may lead to delamination due to thermal shock (Use Sikafloor® -
19N PurCem (CN) or Sikafloor® -20N PurCem (CN) ).
■ Colour uniformity cannot be completely guaranteed from batch to batch
(numbered). Take care when using Sikafloor® PurCem products to draw from
inventory in batch number sequence, do not mix batch numbers in a single floor
area.
■ Always allow a minimum of 48 hours after product application prior to placing
into service in proximity with food stuffs.
■ Products of the Sikafloor® - PurCem® (CN) product range are subject to yellowing
when exposed to UV radiation. There are no measurable losses of other properties
when this occurs and it is a purely aesthetical matter. Products can be used outside
provided the change in appearance is acceptable by the customer.
Caution Component A - Frequent or prolonged skin contact may cause some local short
term skin irritation. Avoid eyes contact, may cause slight transient irritation.
Component B - Harmful by inhalation. Irritating to eyes, respiratory system and
skin. May cause sensitization by inhalation and skin contact.
Component C and D- Risk of serious damage to eyes. In case of contact with
eyes, rinse immediately with plenty of water. May cause skin irritation. Avoid
breathing dusts. Respirable dusts could if inhaled over a prolonged period
constitute a health hazard.
Consult product label for additional information.
First Aid
In case of skin contact, wash thoroughly with soap and water. For eye contact, flush
immediately with plenty of water for at least 15 minutes. Contact a physician
immediately. For respiratory problems, transport victim to fresh air.
For more information, consult Sika Material Safety Data Sheet.
Value Base
All technical data stated in this Product Data Sheet are based on laboratory tests.
Actual measured data may vary due to circumstances beyond our control.
Local Restrictions Please note that as a result of specific local regulations the performance of this
product may vary from country to country. Please consult the local Product Data
Sheet for the exact description of the application fields.
Health and Safety
Information
For information and advice on the safe handling, storage and disposal of chemical
products, users shall refer to the most recent Material Safety Data Sheet containing
physical, ecological, toxicological and other safety-related data.5
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Notes:
The information, and, in particular, the recommendations relating to the application and end-use of Sika products, are given in
good faith based on Sika's current knowledge and experience of the products when properly stored, handled and applied under
normal conditions in accordance with Sika’s recommendations. In practice, the differences in materials, substrates and actual
site conditions are such that no warranty in respect of merchantability or of fitness for a particular purpose, nor any liability
arising out of any legal relationship whatsoever, can be inferred either from this information, or from any written
recommendations, or from any other advice offered. The user of the product must test the product’s suitability for the intended
application and purpose. Sika reserves the right to change the properties of its products. The proprietary rights of third parties
must be observed. All orders are accepted subject to our current terms of sale and delivery. Users must always refer to the
most recent issue of the local Product Data Sheet for the product concerned, copies of which will be supplied on request.
Sika (China) Ltd.
No.28 Jingdong Road, Suzhou Industrial Park,
JiangSu,P.R.China
Postal Code: 215121
ISO 9001: 2008 ISO 14001:2004
Certificate No.:CC3576 Certificate No.:CC3577
The product is manufactured under a HKQAA
ISO9001/ISO14001
certified quality/environmental management system.
Construction
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