Preparation Technology Of Solvent-Free Polyurethane: A Mini-Review

Solvent-free polyurethanes are synthesized under certain conditions via a rapid reaction between liquid prepolymers. During this process the molecular weight of the polymer is rapidly increased to produce polymeric materials containing a carbamate-based structure at a very fast rate. The organic solvents are completely avoided in the solvent-free polyurethane synthesis process, thus avoiding all the problems associated with the use of organic solvents. Solvent-free polyurethane synthetic leather is extruded directly without adding solvents in the production and processing process, which has the advantages of low VOC emission and environmentally friendly. This review brings together theoretical and experimental research on the application and synthesis and preparation of solvent-free polyurethanes to generate an understanding of the theory and synthesis and preparation techniques associated with solvent-free polyurethanes. The review includes (i) the application and development direction of solvent-free polyurethane, (ii) an overview of the technology of solvent-free polyurethane synthetic leather preparation, (iii) a study of the modification and synthesis of solvent-free polyurethane prepolymers, (iv) a summary of the technology of rapid foam forming of solvent-free polyurethane and its influencing factors, (v) a review of the technology of solvent-free polyurethane synthetic leather preparation. In addition to the review, a corresponding overview of the theoretical and experimental advances in solvent-free delayed foaming technology in recent years and a summary of the technology and experience in the preparation of solvent-free polyurethanes are also presented.