TPU is a new type of plastic. Due to its good processability, weather resistance and environmental protection, TPU is widely used in shoe material, pipe, film, roller, cable and wire and other related industries.
Thermoplastic polyurethane elastomer (TPU for short) is A (AB) N-type block linear polymer. A is A high molecular weight (1000-6000) polyester or polyether, and B is A diol containing 2-12 straight chain carbon atoms. The chemical structure between AB chain segments is linked by diisocyanate, usually MDI.
TPU is cross-linked by intermolecular hydrogen bonds or slightly cross-linked by macromolecular chains, and these two cross-linked structures are reversible as the temperature increases or decreases. In the melting state or solution state intermolecular force weakened, and after cooling or solvent volatilization there are strong intermolecular force together, restore the original solid performance.
TPU has two types of polyester type and polyether type, white irregular spherical or columnar particles, relative density 1.10-1.25, polyether type relative density is smaller than polyester type. The glass transition temperature of polyether type is 100.6-106.1℃, and the glass transition temperature of polyester type is 108.9-122.8℃. The brittleness temperature of polyether type and polyester type is lower than -62℃, and the low temperature resistance of hard ether type is worried about the polyester type.
TPU is characterized by excellent wear resistance, excellent ozone resistance, high hardness, high strength, good elasticity, low temperature resistance, good oil resistance, chemical resistance and environmental resistance, polyether ester hydrolysis stability in wet environment is far more than polyester type.
TPU is non-toxic and tasteless, soluble in methyl-ethyl compound, cyclohexanone, tetrahydrofuran, dioxane, dimethyl formamide and other solvents, but also soluble in toluene, ethyl acetate, butyl ketone, acetone with appropriate proportion of mixed solvents, showing a colorless and transparent state, has good storage stability.
PU is a general term for high polymer compounds produced by the reaction of diisocyanate or polyisocyanate with more than two hydroxyl groups. The main chain contains many repeating NHCOO groups. The commonly used diisocyanates are toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexyl diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexyl methane diisocyanate (HMDI), polymethylene polyphenyl polyisocyanate (PAPI), benzene dimethylene diisocyanate (XDI), etc.
According to the different hydroxyl components used, it can be divided into polyester type and polyether type. It can be used to manufacture plastic manufacturing products, wear-resistant synthetic rubber products, synthetic fibers, hard and soft foam products, adhesives and coatings, etc.
TPU and PU are essentially made of the same material. But when you make these two kinds of glue. They don't use the same formula. These two kinds of glue are divided into many kinds of performance. The characteristics of the glue made by different formulas are not the same. These properties refer to mechanical and physical properties.