Comprehensive Analysis of TPU Pellet Hardness: Parameters, Applications and Precautions for Use
TPU (Thermoplastic Polyurethane), as a high-performance elastomer material, the hardness of its pellets is a core parameter that determines the material’s performance and application scenarios. The hardness range of TPU pellets is extremely wide, usually ranging from ultra-soft 60A to ultra-hard 70D, and different hardness grades correspond to completely different physical properties. The higher the hardness, the stronger the rigidity and deformation resistance of the material, but the flexibility and elasticity will decrease accordingly; on the contrary, low-hardness TPU focuses more on softness and elastic recovery.
In terms of hardness measurement, Shore durometers are commonly used in the industry for testing. Among them, Shore A durometers are suitable for the medium and low hardness range of 60A-95A, while Shore D durometers are mostly used for high-hardness TPU above 95A. Strictly follow the standard procedures when measuring: first, inject TPU pellets into flat test pieces with a thickness of not less than 6mm, ensuring that the surface is free of defects such as bubbles and scratches; then let the test pieces stand in an environment with a temperature of 23℃±2℃ and a relative humidity of 50%±5% for 24 hours. After the test pieces are stable, press the indenter of the durometer vertically on the surface of the test piece, keep it for 3 seconds and then read the value. For each group of samples, measure at least 5 points and take the average to reduce errors.
Yantai Linghua New Material CO.,LTD. has a complete product line covering the needs of different hardness. TPU pellets of different hardness have clear divisions of labor in application fields:
- Below 60A (ultra-soft): Due to their excellent touch and elasticity, they are often used in products with extremely high requirements for softness such as baby toys, decompression grip balls, and insole linings;
- 60A-70A (soft): Balancing flexibility and wear resistance, it is an ideal material for sports shoe soles, waterproof sealing rings, infusion tubes and other products;
- 70A-80A (medium-soft): With balanced comprehensive performance, it is widely used in scenarios such as cable sheaths, automobile steering wheel covers, and medical tourniquets;
- 80A-95A (medium-hard to hard): Balancing rigidity and toughness, it is suitable for components that require a certain supporting force such as printer rollers, game controller buttons, and mobile phone cases;
- Above 95A (ultra-hard): With high strength and impact resistance, it has become the preferred material for industrial gears, mechanical shields, and heavy equipment shock pads.
When using TPU pellets, the following points should be noted:
- Chemical compatibility: TPU is sensitive to polar solvents (such as alcohol, acetone) and strong acids and alkalis. Contact with them may easily cause swelling or cracking, so it should be avoided in such environments;
- Temperature control: The long-term use temperature should not exceed 80℃. High temperature will accelerate the aging of the material. If used in high-temperature scenarios, heat-resistant additives should be used;
- Storage conditions: The material is highly hygroscopic and should be stored in a sealed, dry and ventilated place with humidity controlled at 40%-60%. Before use, it should be dried in an 80℃ oven for 4-6 hours to prevent bubbles during processing;
- Processing adaptation: TPU of different hardness needs to match specific process parameters. For example, ultra-hard TPU needs to increase the barrel temperature to 210-230℃ during injection molding, while soft TPU needs to reduce the pressure to avoid flash.
Post time: Aug-06-2025