The change in abrasion resistance of TPE flooring at low temperatures is a result of the combined effects of material properties, environmental conditions, and usage scenarios. Its core mechanism stems from the profound influence of low temperatures on molecular chain motion, surface hardness, and friction mechanisms, requiring analysis from four dimensions: material formulation, processing technology, environmental interaction, and structural design.
The inhibition of molecular chain motion by low temperatures is the foundation of changes in abrasion resistance. TPE material is composed of thermoplastic elastomers, whose molecular chains exhibit high mobility at room temperature, dispersing stress through chain segment sliding. However, when the ambient temperature decreases, the thermal motion of the molecular chains weakens, and the mobility of chain segments is restricted, leading to a significant increase in material hardness. This hardening effect prevents the floor surface from absorbing energy through elastic deformation when subjected to friction, instead forcing it to directly resist wear with rigidity, thus exacerbating surface material peeling. For example, at -20℃, the mobility of TPE molecular chains may decrease by more than 50%, directly leading to an increased mass loss rate in abrasion resistance tests.
Changes in surface hardness are a direct manifestation of the impact of low temperatures on abrasion resistance. The hardness of TPE flooring increases with decreasing temperature, a characteristic reflected in a significant increase in Shore hardness readings. However, this increase in hardness does not linearly improve wear resistance; instead, it can be counterproductive due to increased brittleness. When the hardness exceeds a certain critical value, the material is more prone to cracking during friction. These cracks propagate under repeated stress, leading to micro-scraping. This brittle wear mechanism is distinctly different from the plastic wear mechanism at room temperature, resulting in a non-linear "increase then decrease" characteristic in the wear resistance of TPE flooring at low temperatures.
The change in friction mechanism at low temperatures further complicates the change in wear resistance. At room temperature, friction on TPE flooring is primarily adhesive wear, where surface molecular chains form temporary bonding points with the wear-bearing component, and wear occurs through tearing at these bonding points. However, low temperatures reduce the mobility of surface molecular chains, weakening adhesion, and replacing it with an abrasive wear mechanism. At this temperature, hard particles in the environment (such as dust and gravel) cut into the material surface under frictional force, forming cutting marks. This shift in mechanism means that the wear rate at low temperatures is closely related to particle size, shape, and distribution, rather than simply depending on the material's inherent hardness.
Additives in the material formulation have a moderating effect on low-temperature wear resistance. Plasticizers improve flexibility by reducing intermolecular chain forces, but excessive addition may lead to precipitation at low temperatures, thus reducing wear resistance. Inorganic fillers (such as calcium carbonate) can increase hardness, but particle size must be controlled to avoid stress concentration-induced cracking. Cold-resistant agents (such as phthalates) maintain chain segment mobility below -30°C by disrupting molecular chain crystallinity, thereby slowing down the increase in hardness. For example, adding 5% cold-resistant agent can improve the wear resistance of TPE flooring by about 30% at -25°C, but this must be balanced against its conflict with mechanical properties.
The processing technology affects low-temperature wear resistance in terms of microstructure. The cooling rate during injection molding determines the grain size; rapid cooling forms fine grains, which improves low-temperature toughness; while slow cooling leads to coarse grains, which easily cause brittle fracture. Furthermore, the compatibility of SEBS and PP in the blending process directly affects low-temperature performance. Poor compatibility leads to phase separation and stress concentration points. By optimizing the screw assembly and temperature profile, the phase region size can be controlled below 1μm, significantly improving low-temperature wear resistance.
Dynamic loads in actual use scenarios exacerbate the complexity of low-temperature wear resistance. In high-traffic areas, TPE flooring needs to withstand high-frequency, low-amplitude impact friction; this load pattern is more prone to fatigue wear at low temperatures. In warehousing scenarios, high-amplitude, low-frequency friction generated by dragging heavy objects can lead to a synergistic effect of surface indentation and cracking. Therefore, optimizing TPE formulations for different scenarios, such as increasing crosslinking density to resist fatigue wear or adding lubricants to reduce indentation, is key to improving low-temperature wear resistance.
The variation in wear resistance of TPE flooring at low temperatures is essentially the result of the combined effects of restricted molecular movement, abrupt changes in surface hardness, transformation of friction mechanisms, and environmental loads. By optimizing the formulation design (such as balancing the ratio of plasticizers and cold-resistant agents), improving the processing technology (such as controlling the cooling rate and phase region size), and adapting to the application scenarios (such as adjusting the crosslinking density for dynamic loads), the wear resistance of TPE flooring under low-temperature conditions can be effectively improved, thereby expanding its application range in cold regions.
