Soudal Silirub MPS - General Purpose Sanitary Grade Acetoxy Silicone

Health & Safety Recommendations

Before using Silirub MPS, it is essential to consult the product label and the relevant Safety Data Sheet to familiarise yourself with appropriate precautions.

The product should only be used in well-ventilated areas, and adequate airflow must be maintained throughout both the application and curing phases to avoid the accumulation of acetic vapours. Standard labour hygiene practices should always be followed, including the use of appropriate personal protective equipment (PPE).

Avoid direct contact with skin and eyes, and ensure that the product is stored safely out of the reach of children.

Substrate Suitability

Silirub MPS is designed for use on a wide range of common building materials, including glass, glazed ceramic, metals, and pre-treated timber. It demonstrates particularly strong performance on non-porous surfaces.

However, it is not suitable for use on polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE, e.g. Teflon®), polyvinyl chloride (PVC), bituminous materials, or untreated concrete.

Due to the diversity of potential substrates and coatings, a preliminary adhesion and compatibility test is recommended before proceeding with any project.

Surface Preparation

Surfaces must be structurally sound, rigid, clean, dry, and completely free from dust, grease, oils, or any contaminants that could impair adhesion. Porous substrates should be primed using Soudal Primer 150 to improve adhesion and surface stability.

Non-porous surfaces may require preparation with a suitable Soudal Cleaner and Degreaser if contamination is present. Care should be taken not to leave any residue from cleaning products, which could affect performance.

Application Method

Silirub MPS should be applied using a standard caulking gun. Once the cartridge is fitted, the product must be applied evenly into the joint, ensuring that no air inclusions are trapped within the sealant bead.

After application, the sealant should be tooled using a spatula or finishing tool dipped in a soapy solution. It is important that the finishing solution only contacts the tooling equipment and not the joint flanks, as this may cause a loss of adhesion at the interface.

For best results, avoid applying or tooling the sealant under direct sunlight, which can cause the finishing solution to evaporate too quickly.

Coverage

Coverage of Silirub MPS depends on the dimensions of the joint being sealed. As a guideline, a standard 260ml cartridge will typically yield approximately 10.4 linear metres of a 5mm x 5mm joint. Coverage rates will vary depending on joint depth and width. 

Please refer to our Guide on How To Measure The Number of Tubes Required For the Job.

Joint Dimensions

• Minimum width for joints: 5mm
  
  

• Maximum width for joints: 30mm
  
  

• Minimum depth for joints: 5mm
  
  

• Recommendation for sealing jobs: joint width = 2 x joint depth

Finishing

After tooling, the sealant will begin to skin within approximately 20 minutes at standard conditions (23°C, 50% relative humidity). Full curing occurs at a rate of around 2 mm per 24 hours.

Once cured, the product forms a flexible, mould-resistant and durable seal. If any smoothing solution is used, care must be taken to prevent it from contaminating the joint surface, as this may negatively affect adhesion.

Cleaning

Uncured product can be removed using Soudal Swipex Cleaning Wipes or a suitable surface cleaner.

Once cured, Silirub MPS can only be removed mechanically, with the aid of Soudal Silicone Remover Spray or Soudal Silicone Remover Gel. Tools should be cleaned immediately after use to prevent product buildup.

Limitations

Silirub MPS should not be used on natural stone surfaces such as marble or granite, as it may cause staining. It is not suitable for sealing applications involving continuous water immersion, such as swimming pools or permanently submerged areas.

It is also not appropriate for polycarbonate bonding (use Silirub PC) or aquarium construction (use Silirub AQ). Direct contact with the secondary sealant of insulated glazing units or the PVB layer of laminated safety glass must be avoided.

In acidic or dark environments, slight discolouration may occur, particularly with white sealants, although UV exposure typically restores the original colour.

Other Information

Silirub MPS conforms to LEED standards for Low-Emitting Materials and meets the criteria of SCAQMD Rule 1168. It is compliant with USGBC LEED 2009 Credit 4.1 regarding low-VOC adhesives and sealants.

As with all reactive sealants, where multiple products are used in the same project, ensure that previously applied sealants are fully cured before applying additional materials. Always store the product in a cool, dry place away from direct sunlight and extreme temperatures, ensuring optimal shelf life and performance.

Q) What is Soudal Silirub MPS and what is it used for?

A) Soudal Silirub MPS is a high-performance, acetoxy curing silicone sealant formulated specifically for sanitary applications in wet or humid indoor environments. Designed to create durable, waterproof, and mould-resistant seals, it is ideal for use in bathrooms, kitchens, utility rooms, and wet rooms. It adheres excellently to non-porous surfaces such as glass, ceramic tiles, enamel, treated metals, and pre-finished timber. Common uses include sealing around baths, sinks, showers, toilets, and tiled surfaces where water exposure and condensation are frequent. Its resistance to mould, combined with its flexible and elastic finish, makes it particularly well-suited to domestic and light commercial settings.

Q) Is Soudal Silirub MPS resistant to mould and mildew?

A) Yes, Soudal Silirub MPS is specifically designed with fungicidal additives to provide long-term resistance to mould and mildew, even in high-humidity environments. This makes it ideal for applications where ongoing hygiene and cleanliness are essential, such as bathrooms, kitchens, and wet rooms. The mould resistance of Silirub MPS helps to maintain a cleaner and more hygienic finish over time and reduces the frequency of maintenance and cleaning required in joints that are frequently exposed to moisture and condensation.

Q) On which materials can Soudal Silirub MPS be applied?

A) Soudal Silirub MPS adheres excellently to a wide range of non-porous substrates including glass, glazed ceramic tiles, anodised or coated metals, aluminium, enamel, and pre-treated wood. While it is particularly effective on these common surfaces, it is not suitable for use on natural stone (such as marble or granite), or on materials like polyethylene (PE), polypropylene (PP), PTFE (e.g. Teflon®), polycarbonate, or bituminous surfaces. A preliminary adhesion test is recommended on all substrates, especially those with unknown coatings or finishes.

Q) Can Soudal Silirub MPS be used in kitchens and food preparation areas?

A) Yes, Soudal Silirub MPS is suitable for sealing joints in kitchens and food preparation areas, particularly around sinks, splashbacks, countertops, and tiled walls. Its resistance to water, cleaning products, and humidity, along with its fungicidal properties, makes it an excellent choice in environments where hygiene is paramount. However, it should not come into direct contact with food or be used to bond food-grade components. Always ensure that the sealant is fully cured before allowing it to be exposed to splashes or cleaning routines.

Q) Is Soudal Silirub MPS suitable for outdoor use?

A) While Soudal Silirub MPS offers excellent UV resistance and can tolerate exposure to sunlight and temperature fluctuations, it is primarily designed for interior use in sanitary and high-humidity environments. If used externally, it should be limited to sheltered areas not subject to constant water immersion or heavy rainfall. For external glazing or facade work, a neutral cure silicone such as Silirub 2 or SMX-based sealants from the Soudal range would be more appropriate.

Q) How long does Soudal Silirub MPS take to cure?

A) Under standard conditions (23°C and 50% relative humidity), Soudal Silirub MPS will form a skin within approximately 20 minutes and cures at a rate of around 2 mm per 24 hours. Full curing times will depend on the depth of the joint and the ambient temperature and humidity. Joints should not be exposed to water, mechanical stress, or cleaning during the curing period. Proper ventilation will aid the curing process and help disperse the acetic acid vapours released during curing.

Q) Can Soudal Silirub MPS be painted over?

A) No, Soudal Silirub MPS is not paintable. Silicone sealants in general do not accept paint due to their non-stick surface and flexible nature. If paintable joints are required in non-wet areas, consider using a hybrid polymer sealant from the Soudal range, such as Fix ALL Flexi or SMX 506, which can be painted with waterborne paints. For sanitary joints where painting is not necessary, Silirub MPS remains the preferred option due to its mould resistance and durability.

Q) What is the best way to apply Soudal Silirub MPS for a neat finish?

A) Soudal Silirub MPS should be applied using a standard caulking gun. After cutting the nozzle to the desired joint size, the sealant should be applied evenly without introducing air pockets. Immediately after application, tool the sealant using a finishing tool or spatula moistened with a mild soapy water solution. It is crucial that the soapy solution only contacts the tooling instrument, not the substrate, to prevent interference with adhesion. Avoid tooling in direct sunlight, which can cause premature skin formation and affect the finish.

Q) Can Soudal Silirub MPS be used around toilets and urinals?

A) Yes, Soudal Silirub MPS is well-suited for use around toilets, urinals, bidets, and other sanitary fixtures. It provides a hygienic, flexible, and waterproof seal that prevents water ingress and inhibits the formation of mould. Its strong adhesion to glazed ceramics, enamel, and treated metals ensures long-term performance even in frequently used or professionally cleaned areas. Always ensure the surfaces are clean, dry, and free from scale or residues prior to application for best results.

Q) Is Soudal Silirub MPS safe for use in enclosed spaces?

A) Yes, once cured, Soudal Silirub MPS is completely safe for use in enclosed indoor spaces such as bathrooms and utility rooms. During application and curing, however, the product emits acetic acid vapour, which has a strong vinegar-like smell and can be mildly irritating. It is therefore important to ensure adequate ventilation during use. After full curing, there are no lingering odours, and the sealant poses no health risk under normal use.

Q) Can Soudal Silirub MPS be used in swimming pools or permanently submerged areas?

A) No, Soudal Silirub MPS is not suitable for applications involving permanent water immersion. This includes swimming pools, water tanks, fountains, or aquarium installations. For submerged or constantly wet areas, specialist silicone sealants such as Silirub AQ (for aquariums) or neutral-cure products designed specifically for underwater use should be used. Using the wrong product in submerged conditions may lead to bond failure and compromise the water seal.

Q) What cleaning agents can be used on cured Silirub MPS?

A) Once fully cured, Soudal Silirub MPS exhibits excellent resistance to commonly used domestic cleaning agents, including mild bleach solutions, bathroom cleaners, and disinfectants. Abrasive cleaners or strong solvents such as acetone or caustic soda should be avoided, as they may damage the seal or surrounding surfaces. Routine cleaning with non-abrasive, pH-neutral products will help maintain both the appearance and integrity of the seal over time.

Q) Can I use Soudal Silirub MPS on natural stone like marble?

A) No, Soudal Silirub MPS should not be used on natural stone substrates such as marble, granite, sandstone, or limestone. The acetic acid released during curing can cause staining or discolouration on these surfaces. For natural stone sealing, a neutral-cure, non-staining silicone specifically designed for use with natural stone, such as Silirub NS, should be used instead to ensure a safe and stain-free finish.

Q) Is Soudal Silirub MPS suitable for floor-to-wall junctions?

A) Yes, Silirub MPS is suitable for sealing junctions between walls and floors in bathrooms, showers, and wet rooms where water may accumulate or splash. Its flexible, water-resistant properties allow it to form an effective seal that accommodates minor movement between the wall and floor. However, care should be taken to avoid applying it in areas subjected to foot traffic, as cured silicone is not designed to withstand mechanical abrasion.

Q) How should surfaces be prepared before applying Soudal Silirub MPS?

A) All surfaces must be structurally sound, clean, dry, and free of contaminants such as dust, oil, grease, or old sealant residue. Non-porous surfaces can be cleaned using Soudal Surface Cleaner or alcohol-based degreasers. Porous surfaces should be primed using Soudal Primer 150. Avoid the use of oil-based cleaners or soaps, as they may leave residues that interfere with adhesion. For best results, conduct an adhesion test before full-scale application.

Q) Can Soudal Silirub MPS be used in cold or hot environments?

A) Yes, once cured, Soudal Silirub MPS offers excellent temperature resistance, remaining stable and elastic in conditions ranging from -60°C to +120°C. It can be applied at temperatures between +5°C and +35°C. However, the curing process will be slower in colder conditions and faster in warm, humid environments. Avoid applying the product below the minimum recommended temperature, as this may affect adhesion and final curing performance.

Q) What is the movement capability of Soudal Silirub MPS?

A) Soudal Silirub MPS is capable of accommodating joint movement of up to ±25%, in compliance with ISO 11600. This flexibility allows it to perform effectively in joints subject to minor expansion and contraction, such as those between dissimilar materials or in areas where thermal and structural shifts occur. Its elastic modulus and elongation at break values support its durability and resistance to joint fatigue in long-term use.

Q) How should I clean up uncured or excess Silirub MPS?

A) Uncured Silirub MPS can be removed using Soudal Swipex Cleaning Wipes or a suitable silicone remover. Tools should be cleaned immediately after use to prevent the sealant from curing on them. Cured sealant can only be removed mechanically using a scraper or specialist silicone removal products such as Soudal Silicone Remover Gel. Always clean surrounding surfaces promptly to avoid permanent contamination or residue.

Q) Does Soudal Silirub MPS meet low VOC or environmental standards?

A) Yes, Soudal Silirub MPS conforms to recognised environmental and indoor air quality standards, including LEED (Low Emitting Materials) and SCAQMD Rule 1168 for low-VOC adhesives and sealants. This makes it a safer choice for interior use in both residential and commercial settings. Its environmentally responsible formulation supports healthy indoor environments without compromising performance or durability.

Technical Data Sheet

Safety Data Sheet

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