What's the Properties of TPU 3?
Chemical Resistance
TPU exhibits excellent resistance to pure mineral oils, diesel, and greases, making it suitable for automotive and industrial applications. However, additives present in these fluids-especially aromatic compounds and alcohols in fuel blends-can cause reversible swelling or surface degradation. The extent of this swelling is directly related to the concentration of these aggressive components.
Non-polar solvents such as hexane and heptane typically have negligible impact on TPU, while polar solvents like dimethylformamide (DMF), tetrahydrofuran (THF), N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), and dimethyl sulfoxide (DMSO) can readily dissolve TPU, particularly softer grades. Ether-based TPUs tend to swell more than polyester-based ones, and softer TPUs are more prone to solvent-induced expansion than harder variants.
Abrasion Resistance
TPU is well known for its outstanding abrasion resistance, making it an ideal choice for applications such as footwear soles, rollers, belts, and industrial parts subjected to frequent wear. Its wear performance is influenced by several factors, including the friction coefficient, applied stress, and contact area.
When operating under lubricated conditions, TPU experiences significantly reduced wear rates. Lubrication lowers surface friction and prevents excessive heat buildup, which in turn slows material degradation. This makes TPU especially valuable in dynamic or rotating applications where durability is critical over long operational periods.
UV Stability
TPUs made with aromatic diisocyanates (such as MDI) tend to yellow and lose mechanical integrity when exposed to ultraviolet light over time. This degradation is due to the photochemical breakdown of urethane linkages. In contrast, TPUs based on aliphatic diisocyanates (e.g., HDI, H12MDI) offer superior UV resistance, maintaining color and mechanical properties for longer durations.
UV stabilizers such as hindered amine light stabilizers (HALS) and UV absorbers are often added to enhance UV stability. Additionally, incorporating carbon black into the compound can significantly improve resistance to sunlight-induced degradation.
Electrical Properties
Due to their slight hygroscopic nature, TPUs are not typically used in high-voltage insulation applications where high resistivity is essential. However, their flexibility, toughness, and abrasion resistance make them highly suitable as protective sheathing for electrical cables and wires, particularly in environments where mechanical durability is more important than dielectric performance.