The urgent need to protect surfaces against corrosion requires extensive efforts to formulate coating products with diverse properties in today’s industry. In recent years, scientists and chemical engineers have introduced innovations in the polymer industry to meet this need.
Among the most advanced of these developed polymers are modern polyurethane and polyurea coatings. Since an ideal corrosion protection system must be environmentally friendly in all stages of application, installation and service, it must have high durability and resistance to environmental conditions, mechanical damage and chemicals, as well as in terms of material costs, execution, repairs. And maintenance is cost-effective, polyurethane coatings and especially 100% solid polyurea, due to their special properties, meet all these needs.
There are many reasons to want to use 100% solid polyurethane coatings to cover transmission lines. First, the use of these materials has excellent results and these materials are famous for not being harmful. These materials are much more environmentally friendly than traditional anti-corrosion coatings. Second, due to the high cooking speed of these materials, the tube Coated dishes can be tested and buried in fine pores in a few hours. Third, these materials can be cooked at low temperatures: this is not possible with other coatings. These coatings do not require heating to be applied, they can be applied in the thickness or diameter and length of the pipe.
The nature of the reaction of isocyanate and polyol to make polyurethane is calorific. Because of this, the reaction itself provides the heat it needs. As a result, these coatings can be applied at almost any ambient temperature, so it is not uncommon to apply these coatings up to an ambient temperature of 40 ° C below zero without the use of additional heat.
In addition to the properties mentioned,
Hard 100% solid polyurethane has other very good properties which include:
1-No needle hole
2- High hardness and impact
3- Good flexibility
4- Strong adhesion to the metal surface
5- Resistant to water vapor penetration
6- Resistance to separation due to climatic factors
7- Chemical resistance
3- Types of polyurethane coating systems
Polyurethane coatings can be classified according to their type and amount of additive. Sometimes special additives are added to improve the properties of coatings. But these additives are usually added to reduce the price. Of course, it should be noted that additives that reduce the price, also reduce the quality. Adding up to a percentage of filler (especially bitumen) has an effect on reducing the price, but it has a small effect on the quality of the coating. Increasing the percentage or more drastically reduces the price. But it also greatly reduces the properties of the coating. The most common fillers used in 100% solid polyurethanes are bituminous materials. In this case, crude oil, asphalt or tar bitumen are usually used; however, it should be noted that tar bitumen is carcinogenic.