In the lab, we use a tensile testing machine to measure Peeling Strength. For standard bag or upholstery leather, the industry baseline is usually between 1.5kgf/cm and 2.5kgf/cm. However, for premium microfiber leather used in automotive interiors or heavy-duty footwear, peeling strength often needs to reach 4.0kgf/cm or higher. If a supplier cannot provide a recent third-party peeling strength test report, buyers should be highly cautious.
Flex Resistance Testing: Simulating Real-World Cracking Risks
Once made into shoes, sofas, or car seats, leather undergoes countless bending cycles. High-quality synthetic leather should not show surface cracking or whitening under extremely low temperatures or high-frequency flexing.
We typically use the Bally Flexometer for this inspection. The standard requirement is 50,000 continuous flexes at room temperature without damage; for high-standard clients, we test for 30,000 flexes at -20°C. Leather that easily passes the low-temperature Bally test indicates a superior and sufficient formulation of resins and plasticizers.
Base Fabric Analysis: The Invisible “Skeleton” Determines Tear Strength
Many buyers focus only on the surface color and grain, ignoring the base fabric. The base fabric is the skeleton of synthetic leather.
Take a sample and look at the back or the cross-section. High-quality base fabrics (like napped fabrics, warp/weft knitted fabrics, or microfiber bases) feature high yarn density, accurate GSM (grams per square meter), and uniform fiber distribution. If the backing looks sparse, translucent, or easily deforms without bouncing back when pulled hard, it means its Tear Strength and Tensile Strength are extremely poor. Such materials will easily cause “stitch tear” defects during the sewing process.
