Views:5 Author:Site Editor Publish Time: 2021-01-15 Origin:Site
1. For the new machine, the die-spinneret must be installed after a while. It's similar to running in a new car.
2. If the rubber material stays at high temperature and pressure for a long time, it is easy to sinter and carbonize.
3. Small machines are generally defined by the screw diameter, and large machines are defined by the width (width) of the cloth, which is the effective width of the spinneret.
There is no molecular weight distribution data in the inspection report of Yanshan Petrochemical. Generally, the molecular weight distribution of polymerized PP is not as narrow as CR-PP.
1. The small machine needs to use materials with a lower melt index because when the small machine uses materials with a high melt index, because the material flow rate is too fast, the small machine's thermal compensation, wind compensation, and air pressure compensation are too late to keep up.
2. The reason why the meltblown cloth may not meet the standard: the spinneret is too thick and the gap is large, or the weight is not enough and it is too fluffy.
3. Nucleating agents originally have a variety of formulas, all on the market are dried with N11, which is random addition.
4. Most of the meltblown materials used are low-end nucleating agents, which will definitely become brittle. I think that the brittleness is not caused by some low-end nucleating agents, but that some nucleating agents are not effective in solving the problem of later crystallization and the unit cell becomes larger and brittle.
1. The craftsmanship of the soil gun machine is unstable, the machine is unstable, and the accessories can be used as soon as they can be used.
2. The stability of Basel 650Y comes from material stability and homogenization stability.
3. Many spinneret mold materials on the market are not standard materials. Some low-end mold steels are used instead. There will be some subtle cracks invisible to the eye during use. The aperture processing is rough and the precision is poor. It is directly directly without polishing. on board. It causes uneven spinning, poor toughness, different spinning thickness, and easy crystallization.
1. It is said that the flow rate of 32L/min is used for cloth measurement, and the flow rate of 85L/min for mask measurement? Answer: 25g cloth usually uses 32 flow rate, and 50g cloth usually uses 85 flow rate. 32 flow tests the bacterial filtration performance, 85 tests the particle filtration effect.
2. The flow rate of 2.5um depends on the BFE bacterial filtering efficiency, and the flow rate of 85 0.3um depends on the particle filtering effect, such as 909599. It has nothing to do with single and double layers, and the filtering effect largely depends on the electret.
3. What is the problem with cloth crystallization? Answer: There are particles and small holes on the cloth.
1. The sorrow of the small machine, the material is too good, the liquidity is too good. When the hot air is large, the melt is not drawn into silk, but directly blown into sections to form small liquid beads and hit the cloth surface.
2. The temperature must first be determined when adjusting the machine, not the display temperature on the machine, but the actual temperature of the barrel and mold must be confirmed. For many small devices, the sensor has not been calibrated, and the displayed temperature and actual temperature will be very different.
3. The main thing is to break this balance first. I have done a sudden increase in the screw speed. After a short period of operation, it quickly adjusts to the original set speed and slightly reduces the speed. In fact, for the material with 1500 melt index, the temperature is set to above 270, which is a bit high in itself.
1. Consider reducing the output and temperature a little, and it should be stable with the wind pressure and receiving distance.
2. Electret equipment should be purchased with positive electricity, not negative electricity. Because the cloth has a positive charge, it can absorb the negative charge in the air. Isn’t the negative charge on the cloth okay? Answer: When the meltblown cloth is in contact with the skin, the negative charge is more likely to be consumed. If it is positively charged, it will wear off slowly.
3.The better the insulation, the easier it is to generate static electricity. Static electricity can be positive or negative. The fur rubs against the rubber rod. The electrostatic charge on the rubber rod is negative, and the electrostatic charge on the fur is positive. Positive and negative exist at the same time, because: one side has more electrons (negative electricity) and more negative charges, so it shows negative electricity; one side has less electrons (negative electricity), and less negative charges, so it shows positive electricity.
The electret material not only has excellent filtering performance, but also inhibits and kills microorganisms. The researchers applied PTFE electrets with a surface potential of -300~-1500V to Staphylococcus aureus for 1~24h. The results show that electrets with different electret potentials have a killing rate of 6% to 97% against Staphylococcus aureus. The higher the surface potential of the electret, the better the antibacterial effect on Staphylococcus aureus.
P is narrow. Researchers believe that the principle of electrets inhibiting bacterial reproduction and sterilization may be that electrostatic fields and microcurrents stimulate bacteria, causing the bacteria's protein and nucleic acid to mutate, damaging the bacterial cell wall and cell membrane, destroying the bacterial surface structure, and making the cell membrane inside and outside. The biological electret state is destroyed, thereby inhibiting bacterial reproduction and killing bacteria.
The researchers selected polytetrafluoroethylene electrets with surface potentials of -300, -500 and -1000V to act on fibroblasts for 24, 48 and 72 hours, using flow cytometry and transmission electron microscopy to study the formation of negative electrets The effect of fiber cell apoptosis. The results showed that after electrets acted on fibroblasts, compared with the control group, the apoptosis rate of fibroblasts increased from 0.5% to 10% (some up to 15%); electrets acted on fibroblasts for 48 to 72 hours Later, the unique morphological characteristics of apoptosis appeared, and the researchers concluded that the negative electret has the effect of promoting the apoptosis of fibroblasts.
1. As mentioned in the previous article, dust and bacteria/viruses in the air are attached to the particles and are mainly negatively charged. My understanding of the positively charged cloth melt refers to the adsorption of these negatively charged particles.
2. Some people say that because the cloth has a positive charge, it can absorb the negative charge in the air. The cloth is negative The charge adsorption is not good, which will affect the filtering effect of the cloth.
3. The electret masterbatch has little ability to increase static electricity, mainly because it stores electric charges and decays slowly.
1. The melt index of the meltblown material can reach the standard, and the most important thing is the molecular weight distribution. However, many manufacturers have not tested the molecular weight distribution. Most of the melt finger is unstable because the selected base material is unstable, and it is amplified during the degradation process.
2. Fibers used as base materials for meltblown materials have a narrow molecular weight distribution. Answer: Not necessarily. The difference between drawing materials is big, and the fluctuation of others can reach plus or minus 30%. The powders produced by Shanghai SECCO's Zhenhai Refining & Chemical Co., Ltd. are very stable, so I don't know if they can be bought.
3. The unstable amount of degrading agent added by a small modification plant will also cause large fluctuations in the meltblown material.
1. What is the difference between powder and pellets for meltblown base materials? The pellets are more stable, right? Answer: The powder and the degrading agent are more evenly mixed, and the contact area is larger, which has more advantages. Antioxidants are generally added to the pellets, so the modification space is limited.
2. The pellets have a long storage time and the powder degrades quickly, especially in hot weather.
3. When it is not easy to buy, everything will be used, but it will degrade at a different starting point. If the base index is small, add more degrading agent, and if the base index is large, add less. Now the key is that we find a way to eliminate the impact of the instability of the base material, this is the key technology.