The influence of the anti-hydrostatic pressure value in the barrier properties of SMS non-woven fabrics

The anti-static water pressure is an important indicator to measure the barrier performance of SMS products. The higher the anti-static water pressure, the stronger the product's waterproof ability, and the less likely it is for splashed water droplets to penetrate. As long as the ratio of melt blown is controlled between 35% and 37%. Because in addition, the temperature, humidity of the external space, and the spinning of the meltblown die will also affect the hydrostatic pressure value of the product. This is a relative value and needs to be considered comprehensively. Hydrostatic pressure refers to the pressure of a static liquid acting on each unit pressure area. The hydrostatic pressure resistance of the fabric is the hydrostatic pressure that the fabric can withstand to indicate the resistance encountered by water through the fabric. It is an important indicator of the water barrier performance of the fabric. It is of great significance in medical protective equipment. As the head use time increases, the anti-hydrostatic pressure value of the product shows a downward trend. Generally, the anti-hydrostatic pressure value of similar products in the initial and final stages will differ by 10mBar~20mBar, but this is a theoretical value. In the actual production process, due to the variety of factory products , Need to make frequent process changes, use different types of polypropylene resin and a variety of masterbatch, so the final product initial and final anti-static water pressure difference of 10mBar~40mBar is allowed. No matter what kind of masterbatch, when the amount of addition increases, the viscosity of the melt will increase significantly. It affects the extrusion process of the melt from the spinneret holes, resulting in uneven spreading, lowering the hydrostatic pressure resistance, and even blocking the spinneret holes in severe cases, forming longitudinal lines on the cloth surface. After polypropylene melt is added to the color masterbatch, it will have an impact on its rheological properties, and different types of color masterbatches have different effects on the rheological properties of polypropylene. The hot wind speed is too high to make the fiber too late to cool, and fall on the mesh curtain in the molten state, and melt with the adjacent fiber, which affects the product's anti-static water pressure performance. In addition, if the hot air volume is too large, it is easy to produce flying silk, which seriously affects the appearance of the fabric. When the amount of hot air is lower than 2700mg/h, as the amount of hot air increases, the drafting of the fiber is strengthened, the fiber fineness is improved, and the hydrostatic pressure of the product shows an upward trend, which is in line with the theoretical results; but when the amount of hot air exceeds 2700mg/h , The anti-hydrostatic pressure value of the product drops instead. The above is related to the impact of the anti-hydrostatic pressure value in the barrier properties of SMS non-woven fabrics.