Polyurethane has polyester type and polyether type two types, white irregular spherical or columnar particles, relative density 1.10-1.25, polyether type food hose relative density is smaller than polyester type. Polyether type glass transition temperature of 100.6-106.1 ℃, polyester type food hose glass transition temperature of 108.9-122.8 ℃. The brittleness temperature of polyether type and polyester type is lower than -62℃, and the low temperature resistance of polyether type is worried than polyester type.
Polyurethane thermoplastic elastomer outstanding features are excellent wear resistance, excellent ozone resistance, hardness, high strength, good elasticity, low temperature resistance, good oil resistance, chemical resistance and environmental performance, in the wet environment polyether type ester hydrolysis stability far more than polyester type.
TPU (thermoplastic polyurethane elastomer) is an emerging plastic species, due to TPU has good processability, weather resistance, environmental protection, is widely used in equipment, tubes (steel wire hose, industrial vacuum hose, TPU steel wire food hose, polyurethane hose), films, rollers, cables and wires and other related industries. Polyurethane thermoplastic elastomer, also known as thermoplastic polyurethane rubber, or TPU for short, is a (AB)n-block linear polymer, A is a high molecular weight polyester or polyether, B is a diol containing 2-12 straight chain carbon atoms, and the chemical structure between the AB chain segments is connected with diisocyanate, usually MDI. Thermoplastic polyurethane rubber is cross-linked by intermolecular hydrogen bonding or lightly cross-linked between macromolecular chains, and the two cross-linked structures are reversible as the temperature increases or decreases. The intermolecular forces are weakened in the molten or solution state, and strong intermolecular forces are joined together again after cooling or solvent evaporation to restore the properties of the original solid.
Polyurethane thermoplastic elastomer is non-toxic, tasteless, soluble in solvents such as methylene ethylene, cyclohexanone, tetrahydrofuran, dioxane, dimethylformamide, etc. It is also soluble in a mixture of toluene, ethyl acetate, butanone, acetone in appropriate proportions, showing a colorless and transparent state, and has good storage stability.
PU polyurethane is a general term for the polymer compound produced by the reaction of diisocyanate or polyisocyanate with compounds with more than 2 hydroxyl groups, which contains many repeating NHCOO groups on the main chain. Commonly used diisocyanates include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), polymethylene polyphenyl polyisocyanate (PAPI), benzylidene diisocyanate (XDI), etc. According to the different hydroxyl components used, they can be divided into two categories: polyester type and polyether type. It can be used in the manufacture of plastic products, wear-resistant synthetic rubber products, synthetic fibers, hard and soft foam products, adhesives and coatings, etc.
TPU and PU are essentially made up of the same material. But in making these two kinds of adhesive materials. They do not use the same formula. These two kinds of rubber are divided into many kinds of properties.
