Rigid and flexible polyurethanes are two distinct categories of polyurethanes with significant differences in their properties and applications. Here is an overview of the main differences between rigid and flexible polyurethanes:
Structure and stiffness: Rigid polyurethanes have a solid and rigid structure, similar to hard plastic, while flexible polyurethanes have a soft and elastic structure. This difference in structure gives rigid polyurethanes greater rigidity and strength, while flexible polyurethanes are characterised by high flexibility and resilience.
Density: Rigid polyurethanes tend to have a higher density than flexible polyurethanes. The density of rigid polyurethanes can vary from low to high, depending on the formulation and production process, while flexible polyurethanes are generally less dense.
Applications: Rigid polyurethanes are commonly used in applications requiring structural strength, dimensional stability and stiffness. They are used in sectors such as the automotive industry (body panels, structural components), construction (thermal insulation, panels), electronics (protective coatings) and the furniture industry (rigid and resistant parts).
Flexible polyurethanes, on the other hand, are widely used in the footwear industry (soles, insoles), the automotive industry (seat padding, steering wheels), the furniture industry (upholstery for sofas, armchairs) and many other products requiring flexibility and comfort.
Resilience and shock absorption: Flexible polyurethanes have a high resilience and shock absorption capacity due to their elastic structure. This characteristic makes them suitable for applications requiring shock absorption and comfort, such as sports shoes and seat padding. Rigid polyurethanes, on the other hand, may be less resilient and have higher stiffness.
Processability: Flexible polyurethanes are generally easier to work and process than rigid polyurethanes. Their elastic structure allows for better flexibility in casting, spraying or moulding operations, allowing for greater production versatility.
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