Thread Content
Introduction to the Production and Properties of Polyurethane Insulating Paints. Polyurethane (PU): Polyurethane paint was developed in Germany in the late 1940s. Originally, the temperature rating was between 105°C and 130°C; it has now been improved to Class H/180°C, with higher performance. Polyurethane enameled wire is primarily used in electronic products. As Japanese electronics have developed, polyurethane insulation coatings in Japan have, through years of use, achieved characteristics that place them at the leading level worldwide. Polyurethane paint is actually a type of paint composed of two systems: a polyisocyanate resin with chemically \"terminated\" ends, and a polyester or polyimide resin. During furnace heating, the isocyanate releases a “end-capping” agent, which then reacts with the polyester to form a thermoset polyurethane coating. The cost of the raw materials for isocyanate resins is much higher than that of polyester resins, and the ratio in which these two types of raw materials are used directly determines the price of polyurethane insulating paint. The higher the isocyanate ratio, the better the properties of the polyurethane paint in terms of application, direct welding, and pinhole formation. The advantage of polyurethane is that the coating can be directly welded, meaning it can dissolve on molten solder. As a result, components can be welded without having to remove the coating first. This is a great advantage for high-speed production. Although industrial standards specify a welding temperature of 360°C, many manufacturers prefer to complete the welding process at 320°C within just a few seconds.