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Polyol serves as a fundamental raw material in polyurethane sealants, directly influencing key properties like flexibility, adhesion, and chemical resistance. Tailored for sealant formulations, this polyol ensures optimal reactivity with isocyanates, forming a robust polymer network that delivers durable, long-lasting seals.
As a primary reactant, polyol undergoes a cross-linking reaction with isocyanates, forming urethane bonds that constitute the sealant’s molecular framework. This reaction determines the sealant’s basic structure—short-chain polyols create a dense network for rigidity, while long-chain variants introduce flexibility, critical for accommodating substrate movement (e.g., building expansion/contraction).
Flexibility & Elasticity: The molecular weight and functionality of polyol regulate the sealant’s elongation and recovery. High-molecular-weight polyols (e.g., polyether types) enhance stretchability, ideal for dynamic joints in construction or automotive applications.
Hardness Control: Adjusting polyol hydroxyl value modulates cross-link density. Lower hydroxyl numbers reduce cross-linking, yielding softer, more malleable sealants; higher values produce firmer, load-bearing seals.
Chemical Resistance: Polyol type dictates resistance to oils, solvents, and moisture. Polyester polyols boost resistance to hydrocarbons, while polyether polyols excel in water and alkali resistance, suiting humid or industrial environments.
Weatherability: Specially formulated polyols (e.g., with UV-stabilized segments) improve the sealant's tolerance to sunlight, temperature extremes, and ozone, preventing cracking or degradation in outdoor use.
Low-viscosity polyols facilitate homogeneous mixing with fillers (e.g., calcium carbonate), pigments, and catalysts, ensuring smooth extrusion during application. Their compatibility with one-component (moisture-cured) and two-component systems simplifies manufacturing and on-site use.
Ideal for formulating polyurethane sealants used in construction (expansion joints, window glazing), automotive (body seams, glass bonding), and industrial assembly. Compatible with one-component and two-component systems, it meets strict standards for low VOC emissions and long-term durability.
