Mapeflex MS 45
One-component, flexible, thixotropic, mould-resistant, quick-hardening hybrid sealant and adhesive based on sililated polymers, with a high modulus of elasticity, also suitable for damp substrates.
Supplied by SARP & LAB, the only authorised MAPEI distributor in Albania.
Where it is used
- Expansion, fillet and distribution joints on horizontal and vertical surfaces, with movements up to 20% of the average joint width
- Traditional and ventilated façades
- Civil and industrial floors, including those subject to heavy vehicular traffic
- Window and door fittings, cracks, splits and paintable joints
- Tin roofs and metalwork
- Flexible bonds at 3 mm thickness between most building materials, internally and externally, replacing or integrating mechanical fasteners
Why Mapeflex MS 45
- Completely free of silicone and isocyanates; contains no solvents
- EMICODE EC1 Plus, very low emission of volatile organic compounds
- Can be applied on substrates temporarily damp from recent rain or high atmospheric humidity
- High bond strength without primer, and rapid polymerisation
- Resistant to UV rays and to mould, and does not blister even in particularly damp conditions
- Complies with EN 15651-1, EN 15651-3 and EN 15651-4; class F20 HM to ISO 11600
How it is applied
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Prepare the surface
Surfaces must be clean, sound and free of dust, loose parts, oil, grease, wax and old paintwork. Apply masking tape along the joint edges, removing it immediately after smoothing.
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Set the depth
In joints subject to movement the sealant must bond only to the sides: insert Mapefoam closed-cell polyethylene cord. Sealant depth equals the width up to 10 mm, is 10 mm from 11 to 20 mm, and half the width above 20 mm.
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Prime where needed
Mapei Primerseal A on absorbent substrates that are permanently damp, not perfectly solid, or under high stress or prolonged contact with liquids. On non-absorbent surfaces, Mapei Actiprimer M followed by Mapei Primerseal M. On plastic, Primer P after roughening. Wait until it is completely dry.
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Apply as a sealant
Insert the cartridge in a gun, cut the tip, screw on the nozzle and cut it to the required width. Extrude in a continuous flow, avoiding entrapped air.
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Finish
Before the surface film forms, finish with a tool (e.g. Mapei Perfect Seal) moistened with UltraCare Smooth Silicone by Mapei, or smooth dry after protecting the edges with adhesive paper masking tape.
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Use as an adhesive
Small elements: single drops on the back, pressed well down. Large elements: vertical parallel beads 10-15 cm apart. Adjust within 20 minutes at +23°C. Heavy loads may need support for the first 24 hours. Layers must not exceed 3 mm.
Technical data
| Classification (EN 15651-1) | F-EXT-INT-CC, class 20 HM |
| Classification (EN 15651-3) | XS1 |
| Classification (EN 15651-4) | PW-EXT-INT-CC, class 20 HM |
| Application temperature range | from +5°C to +35°C |
| Dust dry | 35 minutes (at +23°C, 50% R.H.) |
| Complete hardening | 3 mm/24 hours, 4 mm/48 hours, 7.5 mm/7 days |
| Shore A hardness (DIN 53505) | 43 |
| Tensile strength (ISO 37 type 3), 28 days at +23°C | 1.50 N/mm² |
| Elongation at failure (ISO 37 type 3), 28 days at +23°C | 500% |
| Modulus of elasticity at +23°C (ISO 8339) | 0.75 N/mm² |
| Springback | 90% |
| Consumption (metres per 300 ml cartridge) | 5 x 5 mm: 12 · 10 x 10 mm: 3 · 15 x 10 mm: 2 · 20 x 10 mm: 1.5 · 30 x 15 mm: 0.6 |
| Packaging | 300 ml cartridges (boxes of 12), 600 ml sausages (boxes of 20); white, grey 111, grey 113, brown, black |
| Storage | up to 15 months (300 ml) and 12 months (600 ml), in original packaging, in a dry, cool place |
Source: MAPEI technical data sheet 428-7-2026; typical values. Check the current data sheet before use. Product page at MAPEI
Application precautions
- Do not apply below +5°C, or on dusty or crumbling surfaces
- Do not apply on surfaces with traces of oil, grease or stripping compound, or on bituminous surfaces with bleeding oil
- On damp surfaces or under continuous immersion, mechanical performance and adhesion may be significantly lower than in a dry environment
- For movement above 20%, use Mapeflex MS40 or Mapesil LM; for transparent sealing, use Mapeflex MS Crystal
- When bonding, do not use layers more than 3 mm thick
- Before painting, make sure the sealant is fully polymerised and compatible with the paint
Product for professional use.
Frequently asked questions
How many metres does a cartridge cover?
A 300 ml cartridge gives 12 m at 5 x 5 mm, 3 m at 10 x 10 mm, 2 m at 15 x 10 mm, 1.5 m at 20 x 10 mm, 0.9 m at 25 x 12.5 mm and 0.6 m at 30 x 15 mm. For bonding, consumption depends on the technique (spots or beads).
Can it be applied on damp substrates?
Yes, on substrates temporarily damp from recent rain or high atmospheric humidity. On damp surfaces or under continuous immersion, performance and adhesion may be significantly lower than when dry.
Can it be painted?
Yes, once fully polymerised, with a flexible paint such as Elastocolor Paint. Carry out preliminary tests for compatibility.
Which materials does it bond?
Cement-based materials, bricks, metals, painted surfaces, glass and mirrors, gypsum, wood, ceramic and klinker, insulating materials and many types of plastic.
How quickly does it harden?
At +23°C and 50% R.H. it is dust dry in 35 minutes and hardens 3 mm in 24 hours, 4 mm in 48 hours and 7.5 mm in 7 days. Light foot traffic depends on joint depth.
Is there a warranty?
If required, MAPEI can provide a warranty for each product it sells. Contact us about your case.