I. What is TPU

TPU (Thermoplastic polyurethanes) is also known as thermoplastic polyurethane elastomer rubber. Mainly divided into polyester and polyether types, it has a wide hardness range (60HA-85HD), is wear-resistant, oil-resistant, transparent, and has good elasticity. It is widely used in daily necessities, sporting goods, toys, and decorative materials. Halogen-free flame-retardant TPU can also replace soft PVC to meet the increasing environmental requirements of more and more fields. (TPU crosslinking agent manufacturer)

An elastomer is a high-molecular material whose glass transition temperature is below room temperature, elongation at break is >50%, and has good recovery after removal of external force. Polyurethane elastomers are a special category of elastomers. Polyurethane elastomers have a wide hardness range and performance range, so polyurethane elastomers are a type of polymer material between rubber and plastic. (TPU crosslinking agent manufacturer)

It can be heated and plasticized. There is no or little crosslinking in the chemical structure, and its molecules are basically linear, but there is a certain amount of physical crosslinking. This type of polyurethane is called TPU. (TPU crosslinking agent)

II. Characteristics of TPU

1. Wide hardness range: By changing the ratio of various reaction components of TPU, products with different hardness can be obtained, and with the increase of hardness, the products still maintain good elasticity and wear resistance. (TPU crosslinking agent manufacturer)

2. High mechanical strength: TPU products have outstanding load-bearing capacity, impact resistance, and shock absorption performance. (TPU crosslinking agent manufacturer)

3. Outstanding cold resistance: The glass transition temperature of TPU is relatively low, and it maintains good elasticity, flexibility, and other physical properties even at -35 degrees Celsius. (TPU crosslinking agent manufacturer)

Good processing performance: TPU can be processed using common processing methods for thermoplastic materials, such as injection molding, extrusion, and calendering. At the same time, co-processing TPU with certain polymer materials can obtain polymer alloys with complementary properties. (TPU crosslinking agent manufacturer)

4. Oil resistant, water resistant, and mildew resistant.

5. Good recyclability.

TPU, as an elastomer, is a material between rubber and plastic, as can be seen from its rigidity. The rigidity of TPU can be measured by the elastic modulus. The elastic modulus of rubber is usually 1~10Mpa, TPU is 10~1000Mpa, and plastics (nylon, ABS, PC, POM) are 1000~10000Mpa. TPU has a very wide hardness range, from Shore A 60 to Shore D 80, and has high elasticity throughout the entire hardness range; TPU has flexibility in a wide temperature range of -40~120℃ without the need for plasticizers; TPU has good resistance to oils (mineral oils, animal and vegetable oils and greases, and lubricants) and many solvents; TPU also has good weather resistance and excellent resistance to high-energy radiation. Well-known wear resistance, tear resistance, and flexural strength are excellent; high tensile strength, high elongation, and low long-term compression set are all significant advantages of TPU. (TPU crosslinking agent manufacturer)

The TPU properties introduced here include three aspects: mechanical properties, physical properties, and environmental properties.

1. Mechanical properties: The mechanical properties of TPU elastomers mainly include: hardness, tensile strength, compression performance, tear strength, rebound resilience, wear resistance, flexural fatigue resistance, etc. In addition to these properties, the mechanical properties of TPU elastic plastics also include higher shear strength and impact energy. (TPU crosslinking agent manufacturer)

① Hardness: Hardness is an indicator of a material's resistance to deformation, scratching, and abrasion. TPU hardness is usually determined using Shore A and Shore D durometers. Shore A is used for relatively soft TPU, and Shore D is used for harder TPU. Hardness is mainly determined by the hard segment content in the TPU structure. The higher the hard segment content, the higher the hardness of the TPU. After the hardness increases, other properties of TPU will also change, such as increased tensile modulus and tear strength, increased rigidity and compressive stress (load-bearing capacity), decreased elongation, increased density and dynamic heat generation, and increased environmental resistance. The hardness of TPU has a certain relationship with temperature. From room temperature cooling down to the transition temperature (-4~-12℃), the hardness does not change significantly; at the transition temperature, the hardness of TPU suddenly increases and becomes very hard and loses its elasticity, which is the result of the crystallization of the soft segment. (TPU crosslinking agent manufacturer)

② Relationship between hardness, tensile stress at a certain elongation, elongation at break, and the relationship between hardness and tear strength. As the hardness of TPU increases, the tensile stress at 100% elongation and the tensile stress at 300% elongation increase rapidly, and the elongation at break decreases. This is mainly due to the increase in the hard segment content: the higher the hard segment content, the easier it is for the hard segment phase to form sub-crystals or crystalline structures, increasing the number of physical crosslinks and limiting material deformation. To deform the material, the stress must be increased, thereby increasing the tensile stress at a certain elongation, and at the same time, the elongation at break decreases. The relationship between TPU hardness and tear strength is that as the hardness increases, the tear strength increases rapidly, and the reason is the same as the explanation of the modulus. (TPU crosslinking agent manufacturer)

TPU formulations and properties can be arranged in a wide variety of combinations. However, in the actual design of formulations and industrial production, due to the limitations of raw materials (polyols, polyisocyanates, and chain extenders), the research and development of formulations that can be used in high-end applications is still very difficult. (TPU crosslinking agent manufacturer)

Guangan Ruifeng New Materials Co., Ltd., a TPU crosslinking agent manufacturer, we have mature production processes and can definitely meet your needs.