Professional Polymer Technology
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Polyurethane Glueis the best performance of the interna […]
Polyurethane Glueis the best performance of the international insulation material. The backbone contains a group of polymers of -NHCOO-repeating structural units. English abbreviation PU. By the isocyanate (monomer) and hydroxyl compounds from polymerization. Because of strong polar carbamate group, insoluble in non-polar groups, has good oil resistance, toughness, wear resistance, aging resistance and adhesion. Different materials can be used to adapt to a wide temperature range (-50 ~ 150 ℃) materials, including elastomers, thermoplastic resins and thermosetting resins. Under high temperature intolerance hydrolysis, also not alkaline medium.
Commonly used monomers such as toluene diisocyanate, diphenylmethane diisocyanate and so on. Polyols in three categories: simple polyols (ethylene glycol, glycerol, etc.); terminal hydroxyl-containing polyester oligomers, for the preparation of polyester-type polyurethane; containing hydroxyl-terminated polyether oligomers, used Preparation of Polyether Polyurethane. The method of polymerization differs depending on the nature of the material. Synthesis of elastomers when the first low molecular weight glycol, and then with excess aromatic or aliphatic isocyanate reaction, the formation of isocyanate (-NCO) -based prepolymer, and then with the polyol chain extension, the thermoplastic elastomer Body; if the diamine chain extension and further cross-linked to obtain cast-type elastomer. The prepolymer is chain-extended with hydrazine or diamine to obtain elastic fiber. When the isocyanate excess prepolymer is mixed with the catalyst and the foaming agent, the rigid foam can be directly obtained. Such as monomer, polyether, water, catalyst, etc., a one-step reaction can be a flexible foam. Monomers and polyols in the solution reaction, available coatings; adhesive with polyisocyanate monomer and low molecular weight polyester or polyether in the use of mixing and reaction.
Polyurethane elastomer is used as roller, conveyor belt, hose, auto parts, sole, synthetic leather, electric wire and cable and medical artificial organ etc .; soft foam used in vehicle, room, clothing lining, rigid foam Insulation, and low foaming synthetic wood, coatings for advanced vehicles, furniture, wood and metal protection, pool dams and building anti-leakage materials, and fabric coating. Adhesive for metal, glass, ceramics, leather, fiber, etc. have a good adhesion. In addition, polyurethane can also be made into emulsion, magnetic materials.