How does automotive synthetic leather cope with performance changes in extremely high/low temperature environments

Automotive interior materials, particularly synthetic leather, face rigorous testing in diverse climates around the world. From the scorching deserts of the Middle East to the bitter cold of Siberia, automotive synthetic leather must maintain its mechanical properties, aesthetic appearance, and ride comfort in extreme high and low temperature environments. This durability and stability are core criteria for measuring the professional quality of automotive-grade synthetic leather.

Challenges of Extremely High Temperatures and Countermeasures for Polymer Materials

1. Optimizing Thermal Aging and Hydrolysis Resistance

Challenge: Polyurethane (PU) synthetic leather is highly susceptible to hydrolysis in high temperature and high humidity environments, leading to material degradation, surface stickiness, cracking, and even peeling (commonly known as "hydrolysis"). Polyvinyl chloride (PVC), on the other hand, can become hard, sticky, or brittle due to plasticizer migration.

Professional Countermeasures:

PU System: Polycarbonate diol (PCDL), with superior high temperature and hydrolysis resistance, is used instead of traditional polyester polyol as the backbone raw material for PU synthetic leather. At the same time, adding a high-efficiency anti-hydrolysis agent (such as carbodiimide) consumes moisture and acidic substances, effectively delaying main chain breakage and significantly improving hydrolysis resistance.

PVC system: Select high-performance plasticizers with high molecular weight and low volatility, such as polymer plasticizers or trimellitate plasticizers, to reduce migration at high temperatures and maintain the material's flexibility and surface dryness.

2. VOC Release and Thermal Stability

Challenge: High temperatures accelerate the release of residual solvents and low-molecular-weight substances within the material, leading to excessive concentrations of volatile organic compounds (VOCs) in the vehicle interior, impacting air quality.

Professional Countermeasures: Automotive-grade synthetic leather strictly adheres to low-VOC production processes, such as using waterborne PU or solvent-free PU technology. Furthermore, by using high-purity raw materials and optimizing the curing process, we ensure that residual monomers and oligomers in the finished product are minimal, meeting stringent automotive VOC standards such as VDA 278 and GB/T 27630.

Performance Degradation at Extremely Low Temperatures While Maintaining Flexibility

In cold regions, where temperatures drop below zero, the molecular chain mobility of synthetic leather is restricted, causing the material to become hard and brittle, impacting comfort and physical durability.

1. Low-Temperature Flexibility and Flex Resistance

Challenge: At low temperatures, synthetic leather below its glass transition temperature (Tg) rapidly loses its elasticity. When pressed, folded, or impacted, it is prone to low-temperature brittle fracture or low-temperature flex cracking.

Professional Countermeasures:

PU System: Adjust the soft segment ratio in the PU formulation, select polyethers or long-chain polyesters with excellent low-temperature flexibility as raw materials, and design a low glass transition temperature.

PVC System: Use specialized low-temperature plasticizers (such as adipates). These plasticizers effectively lower the glass transition temperature of PVC, ensuring the material maintains sufficient softness and flexural strength even at temperatures as low as −30°C or even −40°C.

2. Dimensional Stability and Thermal Stress Management

Challenge: Automotive interiors are typically laminated or molded from multiple materials, each with varying coefficients of thermal expansion. Severe high- and low-temperature cycling can generate significant thermal stress between synthetic leather and the substrate (such as plastic parts or foam layers), potentially leading to delamination or dimensional deformation.

Professional Countermeasures:

Structural Design: Use adhesives and substrates with similar coefficients of thermal expansion to achieve coordinated deformation.

Material selection: Use new environmentally friendly synthetic leather based on POE (Polyolefin Elastomer) or Si-TPV (Silicone Thermoplastic Vulcanizate). They usually have excellent thermal stability and dimensional stability in a wide temperature range, effectively avoiding interior deformation caused by thermal stress.