Water-based technology is becoming more mature, sort out the classification and application of water-based polyurethane!

Polyurethane, or urethane, is a class of polymeric polymers containing repeated amino acid groups with excellent mechanical and chemical properties. In the past, polyurethane was mostly oil-soluble, in recent years, the trend of hydration was formed, and the hydration of polyurethane was becoming more and more mature.
★ water-based polyurethane classification ★
water-based polyurethane has many categories, generally there are several classification methods

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are classified by appearance: water-based polyurethane can be divided into polyurethane emulsion, polyurethane dispersion, polyurethane aqueous solution. The most practical applications are polyurethane emulsions and dispersants, whose appearance characteristics are shown in Table 1.
are classified by curing method. Water-based polyurethane can be divided into two groups, single-group self-drying, radiation curing three.
radiation-cured water-based polyurethanes generally contain double bonds that can be polymerized by light-triggering agents under ultraviolet light conditions.
water-based two-part system is the same as the traditional solvent-based two-part system, that is, A, B two parts need to be mixed, in order to occur cross-curing, the general use of water-based isocyanate curing agent.
single-pack water-based polyurethane can be cured at room temperature or at room temperature.
is classified by the nature of hydro-hydro-based groups.
according to whether the polyurethane molecular side chain or the main chain contains ion groups, that is, whether it belongs to the ion bond polymer, water-based polyurethane can be divided into anion type, cation type, non-ionic type. Water-based polyurethanes containing yin and cations are also known as ionized water-based polyurethanes. A non-ionized water-based polyurethane that does not contain an ion base group.
are classified as polyurethane raw materials.
according to the main low-polyp polyol type can be divided into polyether type, polyester type and polyolefin type, respectively, refers to the use of polyether polyols, polyester polyols, polybutylene glycol and other low-polyols made of water-based polyurethane. There are also polyether-polyester, polyether-polybutylene and other hybrid types. With polyurethane isocyanate raw materials, can be divided into aromatic isocyanate type, fat isocyanate type, lipid ring isocyanate type.
according to the water-based method of polyurethane is divided into self-emulsification method and outer emulsification method.
self-emulsification method, also known as internal emulsification method, refers to the polyurethane chain segment contains hydrophobic components, so that no emulsion can be used to form a stable emulsion method.
external emulsification method is also known as compulsory emulsification method, if the molecular chain contains only a small amount of not enough self-emulsification of hydro-hydroploric chain segments or substumps, or completely does not contain hydroelectrelative ingredients, at this time must be added emulsion to obtain emulsion.
comparison, in the emulsion prepared by the external emulsification legal system, due to the residual hydrophobic small molecule emulsizer, affecting the performance of polyurethane film after curing, and self-emulsification method eliminates this ill. The preparation of water-based polyurethane is mainly based on ion-type self-emulsification.
❤ applications ❤
different types of polycyanate and polyhydroxy compound reactions, can be made with different properties of coatings to meet the needs of various applications. Polyurethane coating film has a series of excellent characteristics, the most prominent advantages are wear resistance, chemical resistance, good toughness, elasticity and bonding to the substrate, can be cured at room temperature or low temperature, so polyurethane coatings in various fields have been widely used, is considered to be the best comprehensive performance of the paint varieties
Water-based polyurethane has the characteristics of wear resistance, flexibility and strong adhesion, wood paint has become an important application area of water-based polyurethane coatings, with broad prospects for development.
a wide variety of automotive paint, there are electrophoresis paint, two-way paint, paint, original paint, repair paint and so on. With the rapid development of the automobile industry, the requirements for automobile coating are getting higher and higher, from the point of view of environmental protection, water-based is the development trend of automotive coatings, automotive surface primers, medium paint, color paint, matte paint and repair paint can use water-based polyurethane. Currently used water-based polyurethane automotive coatings are mainly two-part types.
of steel and metal corrosion is very serious, especially the corrosion prevention of steel has attracted more and more attention at home and abroad. The coating of anti-rust coating is one of the main methods to prevent steel corrosion. Water-based coatings have gradually become the main development direction of coatings because they can effectively overcome the disadvantages of high solvent-based coatings and high pollution.
building coatings require light resistance, weather resistance and other properties, the use of polyurethane dispersion coatings through the adjustment of the parts can make its comprehensive performance fully meet the requirements. Polyurethane dispersive coatings because of its excellent water resistance, durability and weather resistance, the exterior decoration of buildings has outstanding advantages, as a high-grade architectural coatings in the economically developed United States, Europe, a large number of countries.
direction of development
polyurethane paint film plump, bright, with excellent corrosion resistance, adhesion, chemical resistance, weather resistance, in the field of adhesive coatings have been widely used. However, a single emulsion in stability, self-thickening, solid content and polyurethane resin coating water resistance, gloss and other aspects are not satisfactory. Acrylic resin has the advantages of high mechanical strength, anti-aging, anti-yellowing, good water resistance, but there are poor resistance to organic solvents, poor heat resistance, low softening point, poor wear resistance and other shortcomings.
polyurethanes and polyacrylates are highly complementary in performance, combining them to obtain higher-performance high-polymers. The change of polyurethane with acrylic resin in water-based system is one of the important development directions in the future.
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