Melt blown nonwovens, in the nonwovens family, can be regarded as the younger brother. Small quantity and relatively closed technology. 1n recent years, when the air purification market is on fire, meltblown non-woven fabrics, as the main force of filter materials, are on fire. 1n this relatively closed field, the pattern is also changing quietly
as a filter material, meltblown cloth has the advantage of applying static electricity, thus increasing the function of electrostatic adsorption. This kind of adsorption filtration can increase the filtration efficiency without increasing the resistance
the base material of this kind of melt blown cloth is polypropylene, which is a homopolymer polymer material. Polypropylene is a good electret material because of its poor conductivity
electret, “pole” refers to charge, “standing” refers to application
how to apply static electricity to melt blown nonwovens? 1n short, high voltage discharge, charge attached to polypropylene melt blown non-woven fabric< However, this kind of charge is easy to attach and lose. This is not only the fatal weakness of electrostatic melt blown, but also the key point of different melt blown fabrics of different manufacturers, and also the battlefield for the competition of superior electret technology there was a saying before do not use the instrument to judge the quality of the melt blown filter material. With the palm up, put a piece of electrostatic melt blown (larger, too small to explain the problem) on the palm, and then with the palm down, see if the melt blown can be absorbed on the hand if the electrostatic melt blown adsorption does not fall off on the hand, it means that the electrostatic effect is strong and the filtration efficiency is high< 1n fact, this kind of judgment is wrong recently, we have actually tested a lot of materials, which overturns my previous cognition it’s not that those electrostatic melts which are easier to stick to hands are necessarily good melts. Some materials with no static electricity on the surface show good filtration efficiency if you have asked a professional, please give me the answer. Charge is divided into surface charge and volume charge. Bulk charge, more durable. Surface charge, more reflected in the surface. For example, the filter material is very good in the test just now, it sticks to the hand and does not fall off. However, the surface charge is also easy to decay, which makes the filtration efficiency less durable in the past two years, there have been some better materials with more bulk charge by electrostatic melting and spraying. Therefore, in the current market, this simple method has lost its effectiveness and reliability the progress of melt blown electret technology has brought about visible changes in melt blown. Although, the market seems very hot. 1n fact, some manufacturers are drilling hard, while others are floating on the surface when users make choices, they really need to keep their eyes open of course, it should also be noted that this does not mean that, on the other hand, the one that does not stick to the hand must be a good electrostatic meltdown. After all, there is no charge on the surface and inside of the ordinary meltblown, no electrostatic adhesion, all by mechanical filtration, filtration efficiency is only about 30% multiple tests, multiple tests stability, uniformity, durability, can withstand long-term assessment, is really good if you just send the sample to the testing institution and get a report, you think the product is reliable. There are a lot of unreliable factors hidden here the filter material fluctuates. The same cloth does not need to be ordered, the same batch of different rolls, the same manufacturer’s different batches, and even the same roll of products may have different time data. After all, the melt blown process determines that it is impossible for thousands of square meters of filter materials to be uniform< However, the quality of filter material is very important for mask and filter if there is a problem with the filter material, there will be a problem with the quality of the mask and filter element the reality is that problems are often undetected. However, not being found to have a problem does not mean that there will be no problem or that it will never be found with ingenuity and confidence, only reliable inspection can make you feel at ease