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Polyurethane Sealant
Polyurethane sealants are high-performance, flexible solutions used across construction and industrial sectors to protect, seal, and bond a wide range of materials. These versatile products handle movement in joints, offer excellent weather and chemical resistance, and cure into durable finishes that stand up to abrasion and vibration. For specifiers exploring advanced sealants for challenging environments, polyurethane-based options offer a trusted and lasting solution for expansion joints, glazing systems, flooring, and more.
Cromar AlphaChem Polyurethane 25
Cromar AlphaChem Polyurethane 25 is a single component, fast curing, polyurethane based elastomeric sealant used for joints where a highly elastic strong bond is required, with excellent chemical, mechanical and weather resistance. Specially developed for bonding various building materials & sealing of expansion joints Overpaintable...
Cromar AlphaChem Polyurethane FC40
Cromar Alphachem Polyurethane FC40, formerly known as Polyflex HM, is a single component, fast curing, polyurethane based elastomeric sealant used for joints where a highly elastic strong bond is required, with excellent chemical, mechanical and weather resistance. Suitable for use with PROGRP, Flexiglass and Elastathane Extreme Roofing...
Sika SikaFlex 415
One-part polyurethane sealant. Ideal for construction joints, floor and wall joints, crack control in concrete, and general-purpose bonding in various settings. Offers excellent resistance to water, salt water, and weathering, ensuring long-term performance. Accommodates up to ±25% movement for structural flexibility. Ready-to-use...
Mapei Mapeflex PU40
Polyurethane sealant with a low modulus of elasticity, developed for sealing expansion and contraction joints in horizontal and vertical surfaces. Application examples include: Sealing internal and external expansion and distribution joints subject to movement up to 25% in: Façades on civil and industrial buildings Pre-fabricated...
Sikaflex 291i
Sikaflex 291i (available as a pack of 12 x 300cc cartridges) is a non-sag 1-part polyurethane sealant specifically developed for the marine market, which cures on exposure to atmospheric moisture and forms a durable elastomer. 1-part formulation Highly elastic Low odour Non-corrosive Can be over painted Bonds well to a wide variety of...
Mapei Mapeflex PU45 FT Sealant
Mapei Mapeflex PU45 FT Sealant is a paintable, rapid, high modulus polyurethane sealant and adhesive, specially developed for sealing expansion and distribution joints in horizontal and vertical surfaces, including those which are subject to occasional chemical attack by hydrocarbons. From the 24th August 2023, adequate training is required...
Sikaflex 221
Sikaflex 221 is a high quality multi-purpose non-sag 1 component polyurethane sealant that cures on exposure to atmospheric humidity to form a durable elastomer. 1 component formulation - Elastic - Low odour - Resistant to ageing Non-corrosive - Can be overpainted - Can be sanded Bonds well to a wide variety of substrates NSF approved...
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High-Strength Polyurethane Sealants for Construction and Industrial Use
Projects that begin with high-quality interior paint often rely on polyurethane sealants to finish joints, bond dissimilar materials, and add long-term flexibility. These sealants cure into rubber-like films that absorb movement, resist cracking, and prevent moisture ingress. Their strength and elasticity make them essential in environments where vibration, structural shifting, or repeated cleaning can break down weaker jointing materials.
Polyurethane sealants also play a vital role alongside exterior paint in outdoor applications - such as roofing, cladding, window installations, and precast concrete. Their excellent weather, UV, and chemical resistance makes them a superior choice for sealing external elements exposed to the elements. Whether for industrial flooring, curtain walling, or vehicle bodies, polyurethane formulations ensure a secure, flexible seal that performs across a wide range of conditions.
Frequently Asked Questions
Can polyurethane sealants be used on vertical joints?
Yes, polyurethane sealants are suitable for vertical joints. Their non-sag formulations are specifically designed to stay in place after application. When sealing vertical expansion joints or façade elements, the sealant will not slump or drip, allowing for neat, controlled installation. Most products bond well to concrete, brick, metal, and painted surfaces, making them highly effective for vertical applications in both new builds and refurbishments.
Can I overpaint polyurethane sealants?
In many cases, yes. Once fully cured, most polyurethane sealants can be overpainted with flexible paints. However, compatibility testing is strongly recommended, as not all paints will adhere properly. Use paints with similar elasticity and ensure the sealant is completely cured to avoid trapping solvents or causing cracking. Always check product data sheets before overcoating.
What’s the difference between 1-part and 2-part polyurethane sealants?
1-part sealants cure with moisture from the air and are ideal for general use due to their ease of application. 2-part systems require mixing and offer more control over curing speed and performance. These are often chosen for large-scale or demanding projects where faster return to service or specific strength characteristics are needed. Choose based on job size, working conditions, and project specification.