Is polyurethane a plastic product?
The polyurethane elastomer used for roller, conveyor belts, hoses, auto parts, shoe soles, synthetic leather, artificial organs and medical cable; soft foam cushion for a vehicle, bedroom, clothing, rigid foam for insulation, sound-absorbing, packaging, insulation and low foaming synthetic wood, paint, furniture for advanced vehicles wood and metal door, pond dam and building waterproofing materials and fabric coating etc.. Adhesives have good adhesion to metals, glass, ceramics, leather, fibers, etc.. In addition, polyurethane can be made into emulsion, magnetic material and so on.
Commonly used monomers, such as toluene diisocyanate, diisocyanate, two benzene methane, etc.. Polyols can be divided into 3 categories: simple Polyols (ethylene glycol, glycerol etc.); polyester oligomer containing terminal hydroxyl groups, used in the preparation of polyester polyurethane; containing terminal hydroxyl polyether oligomer, used for the preparation of polyether polyurethane. Polymerization methods vary with material properties. Synthetic elastomer before preparation of low molecular weight diols, and aromatic isocyanate and excessive reaction, generate isocyanate terminated prepolymer, and butylene glycol chain extender, thermoplastic elastomer; if using two aromatic diamine chain extender and further crosslinked, get casting elastomer. The prepolymer obtained elastic fiber by hydrazine or two amine chain expansion; the prepolymer with too much isocyanate was mixed with catalyst and foaming agent to obtain the rigid foam. If the monomer, polyether, water, catalyst and other mixed, a step reaction can be obtained soft foam. The monomer reacts with polyols in solution to obtain paint; the adhesive mixes and reacts with polyisocyanate monomers and low molecular weight polyesters or polyethers in use.
Polyurethane material is the best thermal insulation material in the world at present. A class of polymers containing NHCOO - repeating structural units in the backbone. English abbreviation PU. Formed from the polymerization of an isocyanate (monomer) with a hydroxyl compound. Because of the strong polarity of urethane group, insoluble in non-polar group, it has good oil resistance, toughness, wear resistance, aging resistance and adhesion. Materials suitable for a wide range of temperatures (50~150 DEG C) can be prepared from different raw materials, including elastomers, thermoplastic resins, and thermosetting resins. High temperature resistant to hydrolysis, but also resistant to alkaline medium.
