The NTC thermistor manufactured by the existing technology are poorly moisture-proof and wet-resistance in wet environments. When working in a humid environment, because the epoxy material itself moisture-proof performance is not superior, water is easy to penetrate into the NTC thermistor, affecting its accurate performance, can not meet the requirements of detection, protection, control and other work. In addition, the general epoxy resin encapsulation of high temperature can only reach up to 200 ℃, long-term use generally do not allow more than 125 ℃. Only an NTC thermistor with a glass package can withstand high temperatures to 300℃. However, the glass-encapsulated NTC thermistor is not only expensive, but also easy to break its packet head, low service life and poor practicality.
In order to overcome the shortcomings of the existing technology, it is now provided with a high-temperature-resistance, moisture-proof NTC thermistor manufacturing method. The NTC thermistor has far more high temperature and moisture resistance than the existing NTC thermistor, it can work for a long time in up to 250 ℃ and humid environments, and the mechanical strength is better than the glass package thermistor, long service life, strong practicality.
As the above technology further improvement, the first packet sealing layer for high-temperature silicone layer, the second cladding for the silicone layer, the third cladding layer for high-temperature silicone layer. The high temperature resistance range of high temperature solder is 350~400℃, the temperature resistance range of the first cladding layer is 260℃~320℃, the temperature resistance range of the second cladding layer is 280℃~300℃, and the high temperature range value of the third cladding layer is 260℃~320℃.
Advantages of this manufacturing method compared to existing technologies:
(1)in turn through high-temperature solder and three layers of sealing layer for encapsulation, high-temperature solder high temperature range of 350~400℃, the second packet sealing layer used in silicone resin can withstand high temperature to 280℃~300℃, the first cladding and the third sealing layer resistant to high temperature silicone layer plus sustainable resistance to 260 ℃ high temperature, short-term temperature resistance up to 320 ℃, sufficient to ensure that the NTC thermistor is capable of 250 ℃ of high temperature;
(2)The use of high-temperature silicone layer to do the first and third encapsulation, high-temperature silica gel Not only has a good high temperature resistance, but also its moisture-proof and wet performance is very good, can effectively prevent water and steam infiltration to the NTC thermistor better protection, good moisture-proof performance;
(3) in the high temperature and humidity environment below 250 ℃, the NTC thermistor made by this method can completely replace the glass package thermistor, the practicability is strong, the application range is wide.