In the late 1930s, Germany followed the United States in producing nylon fiber. After a lot of systematic research, polyurethane fiber was made in 1941,butIts performance is not as good as onnylon, but polyurethane was found to be availablegluedgluedagent, paint, etc. , especially used as foam plastics, it was gradually promoted and applied in the 1950s.
Polyurethane coating has a series of advantages:
（ 1) The paint film has extremely strong wear resistance and is the most outstanding among various paint types. Therefore, it is widely used as floor paint, deck paint, and yarn tube Paint etc.
（2) Some varieties of coatings (such as epoxy, chlorinated rubber, etc. ) have good protective properties but poor decorative properties; some varieties (such as nitrocellulose paint, etc.) have good decorative properties but poor protective properties. PolyurethanecoatedThe material not only has excellent protective properties, but also has beautiful decorative properties. Therefore, polyurethane coatings are often used in high-end woodware, pianos, large passenger aircraft, etc.
(3) Coating film attachedauthor力 It is strong and can be formulated into an excellent adhesive like epoxy, so the coating has excellent adhesion to a variety of surfaces (wood, metal, glass, cement, rubber, certain plastics, etc.).
（4) The elasticity of the coating film can be adjusted according to needs, and the proportion of ingredients can be adjusted from the extreme Elastic coating that adjusts from firm to extremely soft. General coatings can only be made into rigid coatings and cannot be highly elastic.
（5) coating has comprehensive chemical resistance and acid resistance , alkali, salt liquid, petroleum products, so it can be used as protective coatings in the chemical industry, lining coatings for petroleum storage tanks, etc.
（6) Coatings can be dried at high temperatures and cured at low temperatures. Among the three typical room temperature curing coatings: epoxy, polyurethane, and polyester, epoxy and polyester are in the range of 10℃The following is difficult to cure, only polyurethane coatings0℃can also be cured normally. Therefore, the construction adapts to the long season.
（7）JuAmmoniaEster paint Can be made to last 40℃Low-temperature varieties. It can also be made into high-temperature resistant insulating coatings. The high and low-temperature resistance of the coating can be adjusted according to needssection.
（8) Electromagnetic wire coated with polyurethane paint can be melted without scratching the paint Automatic tin application during soldering, especially suitable for assembly of telecommunications equipment and instruments. The insulation performance of this type of magnet wire decreases very little after being immersed in water.
（9) OK With many other resinscomplexPrepared paint. Many new varieties are made according to different needs.
Due to Due to the above-mentioned excellent properties, polyurethane coatings have been widely used in various aspects such as national defense, infrastructure, chemical anti-corrosion, electrical insulation, wood coatings, etc. The output is increasing day by day, and new varieties have emerged one after another. It is a promising variety. But it also hasonesome shortcomings.
（1) The gloss and color retention is poor. Composed of methyl diisocyanoPolyester made of acid esterAmmoniaEster coatings are not It is resistant to sunlight and is not suitable for making light-colored paint.
（2) is toxic. IsoCyanideAcid esters are harmful to the human body. Aromatic isoCyanideAcid esters are more toxic.
（3) Poor stability. IsoCyanideAcid esters are very reactive, sensitive to water and moisture, and easily absorb moisture. It will be unstable when exposed to water during storage.
（4) Construction requirements are high. Careless operation can easily cause peeling and blistering between layers. Some varieties come in multiple packages, making construction troublesome.
Too much packaging makes construction troublesome.
