TPU (thermoplastic polyurethane) is called thermoplastic polyurethane elastomer rubber in Chinese. Plastic materials, which can be softened or changed repeatedly under certain heat, but can keep the shape unchanged at room temperature, play a supporting and protecting role, and are widely used in soles.
Second, the chemical composition of TPU plastic raw materials:
TPU plastic is a polymer material polymerized by diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), polymer polyol and chain extender.
1, MDI (diphenylmethane diisocyanate) is a white or yellowish solid at room temperature and a colorless to yellowish liquid after melting. This product can be widely used to manufacture microcellular elastomer, thermoplastic elastomer, casting elastomer, artificial leather, synthetic leather, adhesive, coating and sealant. MDI- 100 is solid at room temperature, with low vapor pressure [40℃ vapor pressure < 10-4 mmHg], and low respiratory inhalation and skin absorption toxicity; Can cause moderate eye irritation and mild skin irritation, and can cause skin allergy. The maximum allowable concentration (TLV) of MDI- 100 in the air is 0.02ppm, and MDI series products are classified as Class Ⅲ B flammable liquids in the NFPA standard manual. The so-called Class Ⅲ B combustible substances refer to substances with flash point higher than 93.3℃; According to ASTM D9 (P.M.C.C), the flash point of MDI series products is 177 ~ 227℃. Fire extinguishing medium: carbon dioxide, foam or chemical dry powder fire extinguisher can be used to extinguish the fire.
2, TDI (toluene diisocyanate), TDI is one of the most toxic diisocyanate compounds, it has a special smell, high volatility, it is insoluble in water, soluble in acetone, ethyl acetate, toluene and other organic solvents. TDI is mainly used to produce polyurethane resin and polyurethane foam, which is volatile, so some newly purchased furniture containing such substances will release TDI.
3.BDO alias: 1, 4- dihydroxybutane
Colorless oily liquid, flammable, miscible with water. Soluble in methanol, ethanol and acetone, slightly soluble in ether. The boiling point is 235℃ and the melting point is 20℃. 1℃, flash point (opening) 12 1℃, ignition point 370℃, refractive index 1.446.
Toxicity and protection: toxic. When drinking on patients or injured skin, anesthesia will first occur, causing special lesions in the liver or kidney, and then sudden death due to central nervous system paralysis. Production equipment should be sealed to prevent leakage, and operators should wear protective equipment. People with skin trauma are strictly forbidden to touch this product.
Packaging, storage and transportation: use aluminum, stainless steel, galvanized iron drums or plastic drums. Or use tank cars to store and transport flammable and toxic substances according to regulations. Under the condition of closed packaging and no heat, the storage time is not limited; Under natural conditions, it does not explode or spontaneously ignite, but it is flammable.
Third, the characteristics of TPU:
Wide hardness range: by changing the proportion of various reaction components of TPU plastic raw materials, products with different hardness can be obtained, and with the increase of hardness, their products still maintain good elasticity and wear resistance.
High mechanical strength: TPU plastic raw material products have outstanding bearing capacity, impact resistance and shock absorption performance.
Outstanding cold resistance: TPU plastic raw material has a low glass transition temperature, and still maintains good physical properties such as elasticity and flexibility at MINUS 35 degrees.
Good processability: TPU plastic raw materials can be processed by common processing methods of thermoplastic materials, such as injection molding, extrusion and calendering. At the same time, TPU can be processed with some polymer materials to obtain polymer alloys with complementary properties. Oil-resistant, waterproof and mildew-proof. Good recovery performance.