The melt blown fabric dropped to 90% in the warehouse a few days, and the dehumidifier helped to lock the static electricity without degradation. It is reported that the melt blown fabric with a filtering efficiency lower than 90% in the market is hard to sell now, even though the 90 level melt blown fabric is available everywhere, making more and more melt blown fabric manufacturers go to 95+and 99+, and improving the competitiveness of melt blown fabric products. However, many melt blown fabric manufacturers report that the newly produced melt blown fabric reaches 95+level, or even 99+level, and can fall to 92, 90, or 85 after a few days in the warehouse. What is the reason
At present, the basic requirements for meltblown fabric on the market are that the filtering effect reaches 90%, 95% or 99%, flexibility and strength, which are the most basic requirements. However, many meltblown fabric manufacturers cannot meet this basic requirement at present. They change the raw materials and the imported die head at one time, and even pay a lot of money to ask the machine master to adjust the temperature, and change the distance between the air knife and the wire nozzle, Or adding electret masterbatch, there are still many problems with the cloth that can be produced. Either the cloth becomes hard overnight, has no flexibility or strength, or the masterbatch has been added, and the filtering effect has not improved at all. More customers are crying because they say that they have done electrostatic electret treatment, and that 95+is reached on the same day. The electrostatic ions are greatly reduced the next day, and the filtering effect is reduced to 90, or even 80
If the meltblown cloth is unqualified, it is considered that the equipment and the nozzle are unqualified. Is there any more reason? How many people have seriously studied it? The process of melt blown fabric from raw materials to finished products: polypropylene → modified equipment → modified polypropylene → melt blown equipment → melt blown fabric → electret treatment → cutting into rolls; When the meltblown fabric is up to standard (90+, 95+, 99+), each link must meet the requirements. Any problem in any link will seriously affect the grade of the finished meltblown fabric. In fact, the filtration efficiency of meltblown cloth is a systematic project, which is related to the thickness and density of the wire, the polarity of PP molecules, and the power of the electrostatic generator (electric field strength). However, the filtration efficiency of the original 95 grade drops after a few days of placement, which has a lot to do with electret master batch, storage environment and electret equipment
I. Selecting permanent electret masterbatch
electret means charging. The electret melt blown cloth initially reached level 95+, but the filter effect fell off after a few days, mainly because the electrostatic field was extremely unstable and the charge attenuation caused the filter effect attenuation
At present, there are three kinds of electret masterbatches: tourmaline production, gas silicon production, and nitrogenous chemical fatty acids
The three types of electret masterbatch have their own advantages and disadvantages. The electret masterbatch produced by the gas silicon method is of high efficiency and good durability. It is basically a permanent power storage, easy to disperse, non-toxic and tasteless, and can pass the FDA certification. In general, it has more advantages
After adding electret masterbatch (2%) to the melt blown cloth and conducting corona discharge electret treatment, the sample filtration efficiency has been greatly improved. This is because the electrostatic effect of these electret materials due to electret greatly improves the electrostatic adsorption capacity of the materials. When particles pass near the electret fiber, they will be strongly adsorbed. More importantly, the melt blown cloth made by adding electret masterbatch is still effective after being stored for one year
The environmental humidity has an impact on the generation and loss of static electricity. The moisture in the air and the charge of melt blown briquette will be converted into negative ions, and the loss of charge will affect the filtering efficiency
The temperature and humidity in the workshop and warehouse should be monitored at all times, and the corresponding equipment -- air conditioner, humidifier or dehumidifier should be added to keep the temperature and humidity in the workshop within a certain range
The melt blown cloth shall be sealed in time after production, preferably vacuum packed, and stored dry without contacting with the outside wet air. Avoid moisture regain and dirt
In addition, special attention should be paid to the fact that the meltblown fabrics produced by different machines should not be put together, which will affect each other and neutralize the charge
Melt blown electret is very sensitive to environmental humidity. A customer has conducted an experiment. After being stored for 7 days under normal temperature and high humidity (relative humidity greater than 95% RH), the surface potential of positive and negative corona charged samples has decreased to 28% and 36% of the initial value respectively. At this time, because the meltblown fabric has an open structure, its specific surface area is large and its contact surface with the surrounding environment is larger, making it more sensitive to water vapor, corrosive gas, charged particles of the opposite sex in the environment. At the same time, the corona charging system can only generate low beam energy ion charges, and most of the charges injected during the charging process are deposited on the near surface layer of the fabric surface fiber
When melt blown fabric samples are stored or worked in a high humidity environment, a large amount of charges are lost due to the compensation effect of polar groups in water molecules, atmospheric ions, etc. on the high concentration surface charges on the fibers. If the static ion of the melt blown fabric is gone, it will become an ordinary non-woven fabric! Therefore, high humidity environment must be avoided during the transportation and storage of meltblown fabric. So, how to avoid high humidity environment? There is no doubt that the simplest and most effective way is to use_ Melt blown fabric warehouse dehumidifier and Parkoo series intelligent humidity control dehumidifier can scientifically and reasonably control the storage environment of melt blown fabric, which can effectively ensure that the static electricity of melt blown fabric does not disappear and the filtering efficiency
_ The melt blown cloth warehouse dehumidifier and Parkoo series intelligent humidity control dehumidifier are highly efficient, energy-saving and environment-friendly dehumidifier products manufactured by strict use of professional technology and exquisite workmanship. They have an intelligent humidity constant control system. Users can automatically control the operation and shutdown of the dehumidifier according to production needs, achieve efficient dehumidification effect through automatic control, and reduce the operating cost of the whole machine. Welcome to inquire the details of 95 meltblown cloth falling to 90 days after being put in the warehouse, and the dehumidifier helps to lock the static electricity without degradation
_ Technical parameters and model selection reference of melt blown cloth warehouse dehumidifier and Parkoo series intelligent humidity control dehumidifier:
Product model ------ dehumidification capacity ------ applicable area ------ power ------ power supply ------ circulating air volume ------ net weight
_-- 28(L/D)---30-50(㎡)----420(W)----220V/50Hz---190m ³/ h---15kg
_-- 58(L/D)---50-80(㎡)----670(W)----220V/50Hz---850m ³/ h---25kg
_--- 90(L/D)---90-120(㎡)---1700(W)---220V/50Hz---1125m ³/ h--50kg
_-- 138(L/D)--130-180(㎡)--2000(W)--220V/50Hz--1725m ³/ h--55kg
_-- 168(L/D)--180-230(㎡)--2800(W)--380V/50Hz--2100m ³/ h--120kg
_-- 240(L/D)--240-350(㎡)--4900(W)--380V/50Hz--3000m ³/ h--160kg
_-- 360(L/D)--360-450(㎡)--7000(W)--380V/50Hz--4500m ³/ h--200kg
_-- 480(L/D)--500-700(㎡)--9900(W)--380V/50Hz--6000m ³/ H-230kg
[Requirements for dehumidifier leasing] The lease starting conditions for dehumidifiers are: the number of leased dehumidifiers is ≥ 5, and the lease term is ≥ 30 days
[Dehumidifier rental charging standard] 80-150 yuan/set/day (the price can be determined according to the rental model, rental quantity and rental days)
◎ Precautions for model selection -- The dehumidification capacity and model of dehumidifier are scientifically calculated mainly according to the volume of the used environment space, the size of fresh air volume, the humidity requirements required by the space environment and other specific values. In addition, it should be noted that the relative humidity of the environment is related to the temperature of the environment. The higher the temperature is, the faster the humidity will evaporate. On the contrary, the worse the effect will be. Therefore, when configuring the dehumidifier, you need to select the type under the guidance of professionals, so that you can select the dehumidifier that is most suitable for you
3、 Electrostatic electret equipment shall use positive charge
dust, bacteria and viruses in the air to attach to particles, mainly with negative charge, and melt blown cloth with positive charge, which is easy to absorb these negatively charged particles
The electret should be positively charged, not negatively charged. Because there is a positive charge on the cloth, it can absorb the negative charge in the air. When the melt blown cloth contacts with the skin, the negative charge is easier to be consumed, and the positive charge will be consumed more slowly
There are many specifications of electrostatic electret generators on the market, usually 30KV, 50KV and 120KV. Which product do you want to choose
According to the introduction of an electrostatic equipment engineer, the test shows that 15-50KV is better, and the discharge distance is 4-8cm
If the applied voltage is too high, such as more than 50KV, it is easy to damage the molecular structure of polypropylene. If it is too close, arcing sparks will break through the melt blown cloth. If the distance is too far, the charge will escape everywhere due to scattering, which will waste a lot of charge and cannot be settled in the master batch, resulting in insufficient electrostatic field of the cloth
It should be noted that some electrostatic devices are marked as 120KV, and the actual output voltage is only more than 23 KV
To sum up, 95+melt blown cloth after electrostatic electret treatment must be stored away from moisture during production, transportation and storage to avoid contact with high humidity environment; If the standard meltblown cloth is not sold in time, the electrostatic attenuation and filtering efficiency will be reduced easily if it is not stored well, and the mask will be difficult to meet the standard. For this reason, the corresponding_ Melt blown cloth warehouse dehumidifier and Parkoo series intelligent humidity control dehumidifier are very necessary to effectively control the humidity in the warehouse, and must not be ignored! Otherwise, it will only be a waste of time! All the above news reports about 95 meltblown cloth falling to 90 in a few days in the warehouse and dehumidifier helping to lock static electricity without degradation are provided by Mashima Electric, for your reference only
