1 Development of Polyurethane Adhesives
1.1 Types of Polyurethane Adhesives
1.2 Brief History of Development of Waterborne Polyurethane Adhesives
1.3 Classification of Water-based Polyurethanes
2 Raw materials for water-based polyurethane synthesis
2.1 Polyols
2.2 Diisocyanate
2.3 Chain extender
2.4 Ionization reagents
2.5 Neutralizing agent
2.6 Crosslinking agent
2.7 Solvents
2.8 Catalyst
3 Preparation of waterborne polyurethane
3.1 Principles and Methods
3.2 Synthetic process of self-emulsifying aqueous PU
4 Modification of Waterborne Polyurethane
4.1 Modification with Acrylates - Grafting and Block Copolymerization
4.2 plus cross-linking agent
5 Products and Applications
5.1 Product Features
Table 1 lists the brands, structural characteristics, manufacturers, and main uses of some of the overseas waterborne polyurethane products. Table 2 shows the performance of Dispercoll U series polyurethane aqueous dispersions produced by Bayer. Table 3 is waterborne polyurethane adhesives reported in foreign patents.
5.2 The main application
(1) Wood Processing Adhesives Wood processing is the largest application area for adhesives. Plywood, fiberboard, particleboard commonly used adhesives are urea formaldehyde, melamine-formaldehyde, phenolic resin, etc., but requires wood moisture content within 2%. In general, the moisture content of wood is about 10%. Drying treatment is required for wood glue processing, which consumes a large amount of energy, and the bonding process produces toxic formaldehyde, causing public hazards. The urea-formaldehyde rubber currently used has poor water resistance, and the adhesive surface of the white glue has insufficient water resistance and heat resistance, and the heat-pressure is easy to penetrate the glue. The use of isocyanate emulsion can avoid the above shortcomings, use less, fast curing, and excellent product performance.
