According to the dispersion state, water-based polyurethane can be divided into water-soluble polyurethane, polyurethane dispersion and polyurethane emulsion, and its characteristics are as follows:

According to the emulsification method, water-based polyurethane can be divided into internal emulsification method and external emulsification method. The internal emulsification method refers to the method in which the polyurethane chain segment contains hydrophilic components, so that a stable emulsion can be formed without an emulsifier; the external emulsification method refers to the molecular emulsification method. The chain contains only a small amount of hydrophilic segments or groups that are not sufficient for self-emulsification, or does not contain any hydrophilic components at all. Add an emulsifier and forcefully disperse into a stable emulsion by mechanical stirring. The characteristics are as follows:

By comparison, in the emulsion prepared by the external emulsification method, due to the large amount of residual hydrophilic small molecule emulsifiers, the performance of the cured polyurethane film is affected, and the internal emulsification method eliminates this disadvantage. Therefore, the preparation of waterborne polyurethane is based on ion The internal emulsification method is the main type, and the internal emulsification method can be divided into anionic water-based polyurethane, cationic water-based polyurethane, non-ionic water-based polyurethane, etc. according to the different hydrophilic chain extenders.

According to the method of use, water-based polyurethane can generally be divided into one-component water-based polyurethane and two-component water-based polyurethane. One-component water-based polyurethane can be used directly, which is easy to operate and has a long opening time; The isocyanate curing agent is used after mixing evenly, and the mixed glue must be used up within a certain period of time.

Composition of waterborne polyurethane

Waterborne polyurethane is mainly composed of macromolecular polyols, polyisocyanates, hydrophilic chain extenders, chain extenders, salt-forming agents, catalysts, crosslinking agents and other additives.

Other additives

According to the needs of the industry and the requirements of laws and regulations, it is often necessary to add defoamers, leveling agents, thixotropic agents, light stabilizers, antioxidants, etc.

Application of waterborne polyurethane

Waterborne polyurethane has the advantages of low VOC, low odor, non-combustibility, easy modification and excellent mechanical properties, and is widely used in adhesives, inks, leather finishes, automotive paints and advanced wood paints and other industries.

Waterborne Polyurethane Adhesive

Water-based polyurethane adhesives have good bonding performance and a wide range of adjustable film properties. In addition to being used as coating adhesives for various substrates, they can also be used for bonding various substrates. At present, they have been widely used in shoe adhesives and automotive interiors. Decorative glue, vacuum suction plastic, woodworking glue, etc.

Waterborne Polyurethane Coating

As a finishing agent, water-based polyurethane has good cold resistance, solvent resistance, film-forming properties, bending resistance, wet and dry rub resistance, adhesion, etc., and has been widely used in leather finishing agents, fabric coatings, automotive varnishes, etc.

Waterborne polyurethane ink binder

As an ink binder, water-based polyurethane has excellent adhesion, color development, flexibility and wear resistance.

With the improvement of the national environmental protection control policy, the rapid development of water-based polyurethane is bound to gradually replace oil-based polyurethane. At present, water-based polyurethane leather finishing agent, water-based polyurethane shoe glue, and water-based polyurethane vacuum plastic have become the mainstream products in the industry.